Implement argument_ptr () syscall for handling process arguments

.clang-format

@@ -50,7 +50,7 @@ AlignOperands: false
 SortIncludes: true
 
 # Comments
-ReflowComments: false
+ReflowComments: true
 CommentPragmas: '^ IWYU pragma:'
 
 # Misc

.gdbinit

@@ -0,0 +1,2 @@
+file kernel/build/kernel.elf
+target remote :1234

.gitea/workflows/docs.yaml

@@ -0,0 +1,43 @@
+name: Build documentation
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Install software
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y doxygen make rsync
+
+      - name: Set up python3
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.10'
+
+      - name: Install mkdocs
+        run: |
+          pip install --upgrade pip
+          pip install mkdocs mkdocs-material pymdown-extensions
+
+      - name: Build
+        run: make docs
+
+      - name: Deploy
+        env:
+          SSH_KEY: ${{ secrets.DEPLOY_SSH_KEY }}
+          REMOTE_IP: ${{ vars.DEPLOY_REMOTE_IP }}
+        run: |
+          mkdir -p ~/.ssh
+          echo "$SSH_KEY" > ~/.ssh/id_rsa
+          chmod 600 ~/.ssh/id_rsa
+          ssh-keyscan -H "$REMOTE_IP" >> ~/.ssh/known_hosts
+          chmod -R 777 site
+          rsync -az --delete site/ webuser@"$REMOTE_IP":/home/webuser/mop/

.gitignore

@@ -3,3 +3,4 @@ mop3.iso
 bochs-log.txt
 bochs-com1.txt
 mop3dist.tar
+site/

Makefile

@@ -1,5 +1,7 @@
 platform ?= amd64
 
-include apps.mk
+include make/apps.mk
-include kernel.mk
+include make/kernel.mk
-include dist.mk
+include make/dist.mk
+include make/docs.mk
+include make/libmsl.mk

amd64/flags.mk

@@ -4,7 +4,8 @@ cflags += --target=x86_64-pc-none-elf \
 					-mno-avx \
 					-mno-mmx \
 					-mno-80387 \
-					-mno-red-zone
+					-mno-red-zone \
+					-mcmodel=large
 
 ldflags += --target=x86_64-pc-none-elf \
 					 -Wl,-zmax-page-size=0x1000

amd64/link.ld

@@ -6,34 +6,61 @@ PHDRS {
   text PT_LOAD;
   rodata PT_LOAD;
   data PT_LOAD;
+  bss PT_LOAD;
+  tls PT_TLS;
 }
 
 SECTIONS {
-  . = 0x0000000050000000;
+  . = 0x0000500000000000;
 
   .text : {
     *(.text .text.*)
+    *(.ltext .ltext.*)
   } :text
   
-  . = ALIGN(CONSTANT(MAXPAGESIZE));
+  . = ALIGN(0x1000);
   
   .rodata : {
     *(.rodata .rodata.*)
   } :rodata
 
-  .note.gnu.build-id : {
+  . = ALIGN(0x1000);
-    *(.note.gnu.build-id)
-  } :rodata
-  
-  . = ALIGN(CONSTANT(MAXPAGESIZE));
 
   .data : {
     *(.data .data.*)
+    *(.ldata .ldata.*)
   } :data
    
+  . = ALIGN(0x1000);
+
+  __bss_start = .;
+
   .bss : {
     *(.bss .bss.*)
-  } :data
+    *(.lbss .lbss.*)
+  } :bss
+
+  __bss_end = .;
+  
+  . = ALIGN(0x1000);
+
+  __tdata_start = .;
+
+  .tdata : {
+    *(.tdata .tdata.*)
+  } :tls
+  
+  __tdata_end = .;
+  
+  __tbss_start = .;
+
+  .tbss : {
+    *(.tbss .tbss.*)
+  } :tls
+  
+  __tbss_end = .;
+  
+  __tls_size = __tbss_end - __tdata_start;
 
   /DISCARD/ : {
     *(.eh_frame*)

aux/bochsrc.txt

@@ -1,4 +1,4 @@
-cpu: model=p4_prescott_celeron_336
+cpu: model=p4_prescott_celeron_336, ips=200000000
 
 memory: guest=4096 host=2048
 
@@ -9,6 +9,7 @@ ata0: enabled=1
 ata0-master: type=cdrom, path=mop3.iso, status=inserted
 com1: enabled=1, mode=file, dev=bochs-com1.txt
 pci: enabled=1, chipset=i440fx
+clock: sync=realtime, time0=local
 
 boot: cdrom
 

aux/devel.sh

@@ -8,6 +8,7 @@ else
   make -B all_kernel
 fi
 
+make -B all_libmsl
 make -B all_apps
 make -B all_dist
 ./aux/limine_iso_amd64.sh

aux/format.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+set -x
+
+make -B format_kernel
+make -B format_libmsl
+make -B format_apps

aux/qemu_amd64_debug.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+set -x
+
+qemu-system-x86_64 -M q35 -m 4G -serial stdio -cdrom mop3.iso -smp 4 -s -S $@

docs/building_kernel.md

@@ -0,0 +1,44 @@
+# Building the MOP3 kernel
+
+This article describes, how to build the kernel, how the build system works and prerequisites.
+
+## Preprequistes
+
+- POSIX host system (tested on Linux, may break on other systems)
+- Git
+- GNU make
+- LLVM toolchain/Clang C compiler
+- Xorriso
+
+## Build steps
+
+cd into root of MOP3 source tree.
+
+Build the kernel:
+```
+make -B all_kernel buildtype=<debug|release>
+```
+
+Build essential system applications:
+```
+make -B all_apps
+```
+
+Prepare the ramdisk:
+```
+make -B all_dist
+```
+
+Build ISO image:
+```
+./aux/limine_iso_amd64.sh
+```
+
+Now you have an ISO image, which can be run my QEMU or you can burn it onto a CD.
+
+For the convenience of the developer, there's a magic "do all" script located in `aux`:
+```
+./aux/devel.sh # optionally "./aux/devel.sh debug" for debugging
+```
+
+It does all the previous steps, just packed into a single script.

docs/index.md

@@ -0,0 +1,4 @@
+# MOP3 operating system documentation
+
+MOP3 is a hobby OS project of mine ;).
+

docs/processes_overview.md

@@ -0,0 +1,30 @@
+# Overview of processes in MOP3
+
+## What is a process?
+
+A process is a structure defined to represent an internal state of a user application's environment. This includes
+the necessary stacks, code, data and other resources. A process (usually) has it's own address, but in certain
+circumstances may share it with another process.
+
+## Only processes vs. processes-threads model
+
+### Overview
+
+MOP3 doesn't have a process-thread separation. Ususally in operating systems you'd have a "process", which consists
+of multiple worker threads. For eg. a single-threaded application is a process, which consists of one worker. In MOP3
+we do things a little differently. We only have processes, but some processes may work within the same pool of (generally speaking)
+"resources", such as a shared address space, shared memory allocations, mutexes and so on. An application then consists of
+not threads, but processes, which are loosely tied together via shared data.
+
+#### Processes-threads model diagram
+![Processes-threads model](assets/images/processes-threads.png)
+#### Only processes model diagram
+![Only processes model](assets/images/only-processes.png)
+
+## Scheduling
+
+MOP3 uses a round-robin based scheduler. For now priorities are left unimplemented, ie. every processes has
+equal priority, but this may change in the future.
+
+A good explaination of round-robin scheduling can be found on the OSDev wiki: [the article](https://wiki.osdev.org/Scheduling_Algorithms#Round_Robin)
+

generic/flags.mk

@@ -6,10 +6,16 @@ cflags += -nostdinc \
 					-pedantic \
 					-Wall \
 					-Wextra \
-					-mcmodel=kernel
+					-ffunction-sections \
+					-fdata-sections
+
+cflags += -isystem ../include
 
 ldflags += -ffreestanding \
 					 -nostdlib \
 					 -fno-builtin \
 					 -fuse-ld=lld \
-					 -static
+					 -static \
+					 -Wl,--gc-sections \
+					 -Wl,--strip-all \
+					 -flto

include/m/status.h

@@ -0,0 +1,13 @@
+#ifndef _M_STATUS_H
+#define _M_STATUS_H
+
+#define ST_OK                0
+#define ST_SYSCALL_NOT_FOUND 1
+#define ST_UNALIGNED         2
+#define ST_OOM_ERROR         3
+#define ST_NOT_FOUND         4
+#define ST_BAD_ADDRESS_SPACE 5
+#define ST_PERMISSION_ERROR  6
+#define ST_BAD_RESOURCE      7
+
+#endif // _M_STATUS_H

include/m/syscall_defs.h

@@ -0,0 +1,16 @@
+#ifndef _M_SYSCALL_DEFS_H
+#define _M_SYSCALL_DEFS_H
+
+#define SYS_QUIT          1
+#define SYS_TEST          2
+#define SYS_MAP           3
+#define SYS_UNMAP         4
+#define SYS_CLONE         5
+#define SYS_SCHED         6
+#define SYS_MUTEX_CREATE  7
+#define SYS_MUTEX_DELETE  8
+#define SYS_MUTEX_LOCK    9
+#define SYS_MUTEX_UNLOCK  10
+#define SYS_ARGUMENT_PTR  11
+
+#endif // _M_SYSCALL_DEFS_H

init/Makefile

@@ -1 +1 @@
-include ../user.mk
+include ../make/user.mk

init/init.S

@@ -1,5 +0,0 @@
-.global _start
-_start:
-  pushq $123
-  addq $8, %rsp
-  jmp _start

init/init.c

@@ -0,0 +1,46 @@
+#include <limits.h>
+#include <proc/local.h>
+#include <proc/proc.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string/string.h>
+
+#define MUTEX 2000
+
+LOCAL volatile char letter = 'c';
+
+void app_proc (void) {
+  char arg_letter = (char)(uintptr_t)argument_ptr ();
+
+  letter = arg_letter;
+
+  for (;;) {
+    mutex_lock (MUTEX);
+
+    for (int i = 0; i < 3; i++)
+      test (letter);
+
+    mutex_unlock (MUTEX);
+  }
+
+  process_quit ();
+}
+
+void app_main (void) {
+  mutex_create (MUTEX);
+
+  letter = 'a';
+
+  process_spawn (&app_proc, (void*)'a');
+  process_spawn (&app_proc, (void*)'b');
+  process_spawn (&app_proc, (void*)'c');
+
+  for (;;) {
+    mutex_lock (MUTEX);
+
+    for (int i = 0; i < 3; i++)
+      test (letter);
+
+    mutex_unlock (MUTEX);
+  }
+}

init/src.mk

@@ -1,3 +1,3 @@
-S += init.S
+c += init.c
 
 o += init.o

kernel/.gitignore

@@ -0,0 +1,2 @@
+*.json
+.cache

kernel/amd64/apic.c

@@ -4,8 +4,10 @@
 #include <amd64/msr.h>
 #include <libk/std.h>
 #include <limine/requests.h>
+#include <sync/spin_lock.h>
 #include <sys/debug.h>
 #include <sys/mm.h>
+#include <sys/spin.h>
 #include <sys/time.h>
 #include <uacpi/acpi.h>
 #include <uacpi/status.h>
@@ -15,56 +17,94 @@
 #define IOAPICS_MAX                 24
 #define INTERRUPT_SRC_OVERRIDES_MAX 24
 
-#define LAPIC_ID     0x20  /* ID                       */
+/* ID of Local APIC */
-#define LAPIC_EOI    0xB0  /* End of interrupt         */
+#define LAPIC_ID 0x20
-#define LAPIC_SIVR   0xF0  /* Spurious interrupt vector register */
+/* End of interrupt register */
-#define LAPIC_ICR    0x300 /* Interrupt command register */
+#define LAPIC_EOI 0xB0
-#define LAPIC_LVTTR  0x320 /* LVT timer register */
+/* Spurious interrupt vector register */
-#define LAPIC_TIMICT 0x380 /* Initial count register   */
+#define LAPIC_SIVR 0xF0
-#define LAPIC_TIMCCT 0x390 /* Current count register   */
+/* Interrupt command register */
-#define LAPIC_DCR    0x3E0 /* Divide config register   */
+#define LAPIC_ICR 0x300
+/* LVT timer register */
+#define LAPIC_LVTTR 0x320
+/* Timer initial count register */
+#define LAPIC_TIMICT 0x380
+/* Timer current count register */
+#define LAPIC_TIMCCT 0x390
+/* Divide config register */
+#define LAPIC_DCR 0x3E0
 
-static struct acpi_madt_ioapic apics[IOAPICS_MAX];
+#define DIVIDER_VALUE 0x0B
+
+struct ioapic {
+  struct acpi_madt_ioapic table_data;
+  spin_lock_t lock;
+  uintptr_t mmio_base;
+};
+
+/* Table of IOAPICS */
+static struct ioapic ioapics[IOAPICS_MAX];
+/* Table of interrupt source overrides */
 /* clang-format off */
 static struct acpi_madt_interrupt_source_override intr_src_overrides[INTERRUPT_SRC_OVERRIDES_MAX];
 /* clang-format on */
+/* Count of actual IOAPIC entries */
 static size_t ioapic_entries = 0;
+/* Count of actual interrupt source overrides */
 static size_t intr_src_override_entries = 0;
-static uintptr_t lapic_mmio_base = 0;
 
-extern void amd64_spin (void);
+static spin_lock_t lapic_calibration_lock = SPIN_LOCK_INIT;
 
-static uint32_t amd64_ioapic_read (uintptr_t vaddr, uint32_t reg) {
+/* Read IOAPIC */
-  *(volatile uint32_t*)vaddr = reg;
+static uint32_t amd64_ioapic_read (struct ioapic* ioapic, uint32_t reg) {
-  return *(volatile uint32_t*)(vaddr + 0x10);
+  spin_lock_ctx_t ctxioar;
+
+  spin_lock (&ioapic->lock, &ctxioar);
+  *(volatile uint32_t*)ioapic->mmio_base = reg;
+  uint32_t ret = *(volatile uint32_t*)(ioapic->mmio_base + 0x10);
+  spin_unlock (&ioapic->lock, &ctxioar);
+  return ret;
 }
 
-static void amd64_ioapic_write (uintptr_t vaddr, uint32_t reg, uint32_t value) {
+/* Write IOAPIC */
-  *(volatile uint32_t*)vaddr = reg;
+static void amd64_ioapic_write (struct ioapic* ioapic, uint32_t reg, uint32_t value) {
-  *(volatile uint32_t*)(vaddr + 0x10) = value;
+  spin_lock_ctx_t ctxioaw;
+
+  spin_lock (&ioapic->lock, &ctxioaw);
+  *(volatile uint32_t*)ioapic->mmio_base = reg;
+  *(volatile uint32_t*)(ioapic->mmio_base + 0x10) = value;
+  spin_unlock (&ioapic->lock, &ctxioaw);
 }
 
-static struct acpi_madt_ioapic* amd64_ioapic_find (uint8_t irq) {
+/* Find an IOAPIC corresposting to provided IRQ */
-  struct acpi_madt_ioapic* apic = NULL;
+static struct ioapic* amd64_ioapic_find (uint32_t irq) {
-  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+  struct ioapic* ioapic = NULL;
 
   for (size_t i = 0; i < ioapic_entries; i++) {
-    apic = &apics[i];
+    ioapic = &ioapics[i];
-    uint32_t version = amd64_ioapic_read ((uintptr_t)hhdm->offset + (uintptr_t)apic->address, 1);
+    uint32_t version = amd64_ioapic_read (ioapic, 1);
     uint32_t max = ((version >> 16) & 0xFF);
 
-    if ((irq >= apic->gsi_base) && (irq <= (apic->gsi_base + max)))
+    if ((irq >= ioapic->table_data.gsi_base) && (irq <= (ioapic->table_data.gsi_base + max)))
-      return apic;
+      return ioapic;
   }
 
   return NULL;
 }
 
-void amd64_ioapic_route_irq (uint8_t vec, uint8_t irq, uint64_t flags, uint64_t lapic_id) {
+/*
-  struct acpi_madt_ioapic* apic = NULL;
+ * Route IRQ to an IDT entry of a given Local APIC.
+ *
+ * vec - Interrupt vector number, which will be delivered to the CPU.
+ * irq -Legacy IRQ number to be routed. Can be changed by an interrupt source override
+ *  into a different GSI.
+ * flags - IOAPIC redirection flags.
+ * lapic_id - Local APIC that will receive the interrupt.
+ */
+void amd64_ioapic_route_irq (uint32_t vec, uint32_t irq, uint64_t flags, uint64_t lapic_id) {
+  struct ioapic* ioapic = NULL;
   struct acpi_madt_interrupt_source_override* override;
   bool found_override = false;
-  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
 
   for (size_t i = 0; i < intr_src_override_entries; i++) {
     override = &intr_src_overrides[i];
@@ -77,62 +117,26 @@ void amd64_ioapic_route_irq (uint8_t vec, uint8_t irq, uint64_t flags, uint64_t
   uint64_t calc_flags = (lapic_id << 56) | (flags) | (vec & 0xFF);
 
   if (found_override) {
-    uint8_t polarity = ((override->flags & 0x03) == 0x03) ? 1 : 0;
+    uint32_t polarity = ((override->flags & 0x03) == 0x03) ? 1 : 0;
-    uint8_t mode = (((override->flags >> 2) & 0x03) == 0x03) ? 1 : 0;
+    uint32_t mode = (((override->flags >> 2) & 0x03) == 0x03) ? 1 : 0;
     calc_flags |= (uint64_t)mode << 15;
     calc_flags |= (uint64_t)polarity << 13;
-
-    calc_flags |= flags;
-  } else {
-    calc_flags |= flags;
   }
 
-  apic = amd64_ioapic_find (irq);
+  uint32_t gsi = found_override ? override->gsi : irq;
 
-  if (apic == NULL)
+  ioapic = amd64_ioapic_find (gsi);
+
+  if (ioapic == NULL)
     return;
 
-  uint32_t irq_reg = ((irq - apic->gsi_base) * 2) + 0x10;
+  uint32_t irq_reg = ((gsi - ioapic->table_data.gsi_base) * 2) + 0x10;
 
-  amd64_ioapic_write ((uintptr_t)hhdm->offset + (uintptr_t)apic->address, irq_reg,
+  amd64_ioapic_write (ioapic, irq_reg + 1, (uint32_t)(calc_flags >> 32));
-                      (uint32_t)calc_flags);
+  amd64_ioapic_write (ioapic, irq_reg, (uint32_t)calc_flags);
-
-  amd64_ioapic_write ((uintptr_t)hhdm->offset + (uintptr_t)apic->address, irq_reg + 1,
-                      (uint32_t)(calc_flags >> 32));
-}
-
-void amd64_ioapic_mask (uint8_t irq) {
-  struct acpi_madt_ioapic* apic;
-  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
-
-  apic = amd64_ioapic_find (irq);
-
-  if (apic == NULL)
-    return;
-
-  uint32_t irq_reg = ((irq - apic->gsi_base) * 2) + 0x10;
-
-  uint32_t value = amd64_ioapic_read ((uintptr_t)hhdm->offset + (uintptr_t)apic->address, irq_reg);
-  amd64_ioapic_write ((uintptr_t)hhdm->offset + (uintptr_t)apic->address, irq_reg,
-                      value | (1 << 16));
-}
-
-void amd64_ioapic_unmask (uint8_t irq) {
-  struct acpi_madt_ioapic* apic;
-  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
-
-  apic = amd64_ioapic_find (irq);
-
-  if (apic == NULL)
-    return;
-
-  uint32_t irq_reg = ((irq - apic->gsi_base) * 2) + 0x10;
-
-  uint32_t value = amd64_ioapic_read ((uintptr_t)hhdm->offset + (uintptr_t)apic->address, irq_reg);
-  amd64_ioapic_write ((uintptr_t)hhdm->offset + (uintptr_t)apic->address, irq_reg,
-                      value & ~(1 << 16));
 }
 
+/* Find and initialize the IOAPIC */
 void amd64_ioapic_init (void) {
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
 
@@ -140,7 +144,7 @@ void amd64_ioapic_init (void) {
   uacpi_status status = uacpi_table_find_by_signature (ACPI_MADT_SIGNATURE, &apic_table);
   if (status != UACPI_STATUS_OK) {
     DEBUG ("Could not find MADT table!\n");
-    amd64_spin ();
+    spin ();
   }
 
   struct acpi_madt* apic = (struct acpi_madt*)apic_table.virt_addr;
@@ -153,11 +157,15 @@ void amd64_ioapic_init (void) {
 
     switch (current->type) {
     case ACPI_MADT_ENTRY_TYPE_IOAPIC: {
-      struct acpi_madt_ioapic* ioapic = (struct acpi_madt_ioapic*)current;
+      struct acpi_madt_ioapic* ioapic_table_data = (struct acpi_madt_ioapic*)current;
-      mm_map_kernel_page ((uintptr_t)ioapic->address,
+      mm_map_kernel_page ((uintptr_t)ioapic_table_data->address,
-                          (uintptr_t)hhdm->offset + (uintptr_t)ioapic->address,
+                          (uintptr_t)hhdm->offset + (uintptr_t)ioapic_table_data->address,
-                          MM_PG_PRESENT | MM_PG_RW | MM_PD_RELOAD);
+                          MM_PG_PRESENT | MM_PG_RW);
-      apics[ioapic_entries++] = *ioapic;
+      ioapics[ioapic_entries++] = (struct ioapic){
+          .lock = SPIN_LOCK_INIT,
+          .table_data = *ioapic_table_data,
+          .mmio_base = ((uintptr_t)hhdm->offset + (uintptr_t)ioapic_table_data->address),
+      };
     } break;
     case ACPI_MADT_ENTRY_TYPE_INTERRUPT_SOURCE_OVERRIDE: {
       struct acpi_madt_interrupt_source_override* override =
@@ -170,65 +178,94 @@ void amd64_ioapic_init (void) {
   }
 }
 
-static uintptr_t amd64_lapic_base (void) { return lapic_mmio_base; }
+/* Get MMIO base of Local APIC */
+static uintptr_t amd64_lapic_base (void) { return thiscpu->lapic_mmio_base; }
 
+/* Write Local APIC */
 static void amd64_lapic_write (uint32_t reg, uint32_t value) {
   *(volatile uint32_t*)(amd64_lapic_base () + reg) = value;
 }
 
+/* Read Local APIC */
 static uint32_t amd64_lapic_read (uint32_t reg) {
   return *(volatile uint32_t*)(amd64_lapic_base () + reg);
 }
 
+/* Get ID of Local APIC */
 uint32_t amd64_lapic_id (void) { return amd64_lapic_read (LAPIC_ID) >> 24; }
 
+/* Send End of interrupt command to Local APIC */
 void amd64_lapic_eoi (void) { amd64_lapic_write (LAPIC_EOI, 0); }
 
-void amd64_lapic_tick (uint32_t tick) { amd64_lapic_write (LAPIC_TIMICT, tick); }
+/*
-
+ * Calibrate Local APIC to send interrupts in a set interval.
+ *
+ * us - Period length in microseconds
+ */
 static uint32_t amd64_lapic_calibrate (uint32_t us) {
-  amd64_lapic_write (LAPIC_DCR, 0x03);
+  spin_lock_ctx_t ctxlacb;
+
+  spin_lock (&lapic_calibration_lock, &ctxlacb);
+
+  amd64_lapic_write (LAPIC_DCR, DIVIDER_VALUE);
 
   amd64_lapic_write (LAPIC_LVTTR, SCHED_PREEMPT_TIMER | (1 << 16));
-
   amd64_lapic_write (LAPIC_TIMICT, 0xFFFFFFFF);
 
   sleep_micro (us);
 
+  amd64_lapic_write (LAPIC_LVTTR, SCHED_PREEMPT_TIMER | (0 << 16));
   uint32_t ticks = 0xFFFFFFFF - amd64_lapic_read (LAPIC_TIMCCT);
+  DEBUG ("timer ticks = %u\n", ticks);
+
+  spin_unlock (&lapic_calibration_lock, &ctxlacb);
 
   return ticks;
 }
 
+/*
+ * Starts a Local APIC, configures LVT timer to send interrupts at SCHED_PREEMPT_TIMER.
+ *
+ * ticks - Initial tick count
+ */
 static void amd64_lapic_start (uint32_t ticks) {
-  amd64_lapic_write (LAPIC_DCR, 0x03);
+  amd64_lapic_write (LAPIC_DCR, DIVIDER_VALUE);
-
-  amd64_lapic_write (LAPIC_LVTTR, SCHED_PREEMPT_TIMER | (1 << 17));
-
   amd64_lapic_write (LAPIC_TIMICT, ticks);
+  amd64_lapic_write (LAPIC_LVTTR, SCHED_PREEMPT_TIMER | (1 << 17));
 }
 
-uint64_t amd64_lapic_init (uint32_t us) {
+/*
+ * Initialize Local APIC, configure to send timer interrupts at a given period. See
+ * amd64_lapic_calibrate and amd64_lapic_start.
+ */
+void amd64_lapic_init (uint32_t us) {
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
 
   amd64_wrmsr (MSR_APIC_BASE, amd64_rdmsr (MSR_APIC_BASE) | (1 << 11));
 
   uintptr_t lapic_paddr = amd64_rdmsr (MSR_APIC_BASE) & 0xFFFFF000;
-  lapic_mmio_base = lapic_paddr + (uintptr_t)hhdm->offset;
+  thiscpu->lapic_mmio_base = lapic_paddr + (uintptr_t)hhdm->offset;
 
-  mm_map_kernel_page (lapic_paddr, lapic_mmio_base,
+  mm_map_kernel_page (lapic_paddr, thiscpu->lapic_mmio_base, MM_PG_PRESENT | MM_PG_RW);
-                      MM_PG_PRESENT | MM_PG_RW | MM_PD_LOCK | MM_PD_RELOAD);
 
   amd64_lapic_write (LAPIC_SIVR, 0xFF | (1 << 8));
 
-  uint32_t ticks = amd64_lapic_calibrate (us);
+  thiscpu->lapic_ticks = amd64_lapic_calibrate (us);
-
+  amd64_lapic_start (thiscpu->lapic_ticks);
-  amd64_lapic_start (ticks);
+}
-
+
-  return ticks;
+/*
+ * Send an IPI to a given Local APIC. This till invoke an IDT stub located at vec.
+ *
+ * lapic_id - Target Local APIC
+ * vec - Interrupt vector/IDT stub, which will be invoked by the IPI.
+ */
+void amd64_lapic_ipi (uint32_t lapic_id, uint32_t vec) {
+  /* wait for previous IPI to finish */
+  while (amd64_lapic_read (LAPIC_ICR) & (1 << 12)) {
+    __asm__ volatile ("pause");
   }
 
-void amd64_lapic_ipi (uint8_t lapic_id, uint8_t vec) {
   amd64_lapic_write (LAPIC_ICR + 0x10, (lapic_id << 24));
-  amd64_lapic_write (LAPIC_ICR, vec);
+  amd64_lapic_write (LAPIC_ICR, vec | (1 << 14));
 }

kernel/amd64/apic.h

@@ -3,15 +3,12 @@
 
 #include <libk/std.h>
 
-void amd64_ioapic_route_irq (uint8_t vec, uint8_t irq, uint64_t flags, uint64_t lapic_id);
+void amd64_ioapic_route_irq (uint32_t vec, uint32_t irq, uint64_t flags, uint64_t lapic_id);
-void amd64_ioapic_mask (uint8_t irq);
-void amd64_ioapic_unmask (uint8_t irq);
 void amd64_ioapic_init (void);
 
 uint32_t amd64_lapic_id (void);
-void amd64_lapic_tick (uint32_t tick);
 void amd64_lapic_eoi (void);
-void amd64_lapic_ipi (uint8_t lapic_id, uint8_t vec);
+void amd64_lapic_ipi (uint32_t lapic_id, uint32_t vec);
-uint64_t amd64_lapic_init (uint32_t us);
+void amd64_lapic_init (uint32_t us);
 
 #endif // _KERNEL_AMD64_APIC_H

kernel/amd64/bootmain.c

@@ -3,10 +3,13 @@
 #include <amd64/hpet.h>
 #include <amd64/init.h>
 #include <amd64/intr_defs.h>
+#include <amd64/msr-index.h>
+#include <amd64/msr.h>
 #include <aux/compiler.h>
 #include <irq/irq.h>
 #include <libk/std.h>
 #include <limine/limine.h>
+#include <limine/requests.h>
 #include <mm/liballoc.h>
 #include <mm/pmm.h>
 #include <proc/proc.h>
@@ -14,6 +17,7 @@
 #include <sys/debug.h>
 #include <sys/mm.h>
 #include <sys/smp.h>
+#include <sys/syscall.h>
 #include <sys/time.h>
 #include <uacpi/uacpi.h>
 
@@ -21,11 +25,17 @@
 
 ALIGNED (16) static uint8_t uacpi_memory_buffer[UACPI_MEMORY_BUFFER_MAX];
 
+/*
+ * The kernel starts booting here. This is the entry point after Limine hands control. We set up all
+ * the necessary platform-dependent subsystems/drivers and jump into the init app.
+ */
 void bootmain (void) {
-  struct cpu* bsp_cpu = cpu_make ();
+  struct limine_mp_response* mp = limine_mp_request.response;
-  cpu_assign (bsp_cpu->id);
+
+  struct cpu* bsp_cpu = cpu_make (mp->bsp_lapic_id);
 
   amd64_init (bsp_cpu, false);
+  syscall_init ();
   amd64_debug_init ();
   pmm_init ();
   mm_init ();
@@ -39,14 +49,6 @@ void bootmain (void) {
 
   smp_init ();
 
-  /* busy wait for cpus to come online */
-  for (volatile int i = 0; i < INT_MAX; i++)
-    ;
-
-  mm_init2 ();
-
-  __asm__ volatile ("sti");
-
   proc_init ();
 
   for (;;)

kernel/amd64/debug.c

@@ -6,22 +6,40 @@
 #include <sync/spin_lock.h>
 #include <sys/debug.h>
 
+/* Port for printing to serial */
+/* TODO: Make this configurable */
 #define PORT_COM1 0x03F8
+/* debugprintf buffer size */
 #define BUFFER_SIZE 1024
+/*
+ * Lock, which ensures that prints to the serial port are atomic (ie. one debugprintf is atomic in
+ * itself).
+ */
+static spin_lock_t serial_lock = SPIN_LOCK_INIT;
 
-spin_lock_t serial_lock = SPIN_LOCK_INIT;
+static bool debug_init = false;
 
+/* Block until TX buffer is empty */
 static bool amd64_debug_serial_tx_empty (void) {
   return (bool)(amd64_io_inb (PORT_COM1 + 5) & 0x20);
 }
 
+/* Write a single character to serial */
 static void amd64_debug_serial_write (char x) {
   while (!amd64_debug_serial_tx_empty ())
     ;
   amd64_io_outb (PORT_COM1, (uint8_t)x);
 }
 
+/*
+ * Formatted printing to serial. serial_lock ensures that all prints are atomic.
+ */
 void debugprintf (const char* fmt, ...) {
+  spin_lock_ctx_t ctxdbgp;
+
+  if (!debug_init)
+    return;
+
   char buffer[BUFFER_SIZE];
   memset (buffer, 0, sizeof (buffer));
 
@@ -34,16 +52,17 @@ void debugprintf (const char* fmt, ...) {
 
   const char* p = buffer;
 
-  spin_lock (&serial_lock);
+  spin_lock (&serial_lock, &ctxdbgp);
 
   while (*p) {
     amd64_debug_serial_write (*p);
     p++;
   }
 
-  spin_unlock (&serial_lock);
+  spin_unlock (&serial_lock, &ctxdbgp);
 }
 
+/* Initialize serial */
 void amd64_debug_init (void) {
   amd64_io_outb (PORT_COM1 + 1, 0x00);
   amd64_io_outb (PORT_COM1 + 3, 0x80);
@@ -52,4 +71,6 @@ void amd64_debug_init (void) {
   amd64_io_outb (PORT_COM1 + 3, 0x03);
   amd64_io_outb (PORT_COM1 + 2, 0xC7);
   amd64_io_outb (PORT_COM1 + 4, 0x0B);
+
+  debug_init = true;
 }

kernel/amd64/flags.mk

@@ -4,7 +4,8 @@ cflags += --target=x86_64-pc-none-elf \
 					-mno-avx \
 					-mno-mmx \
 					-mno-80387 \
-					-mno-red-zone
+					-mno-red-zone \
+					-fno-omit-frame-pointer
 
 ldflags += --target=x86_64-pc-none-elf \
 					 -Wl,-zmax-page-size=0x1000

kernel/amd64/gdt.h

@@ -5,8 +5,21 @@
 #include <libk/std.h>
 #include <proc/proc.h>
 
+#define GDT_KCODE 0x08
+#define GDT_KDATA 0x10
+#define GDT_UDATA 0x18
+#define GDT_UCODE 0x20
+#define GDT_TSS   0x28
+
+/* Size of kernel stack */
 #define KSTACK_SIZE (32 * 1024)
 
+/*
+ * 64-bit GDT structure. For more info see:
+ * - https://wiki.osdev.org/Global_Descriptor_Table
+ * - https://wiki.osdev.org/GDT_Tutorial
+ */
+
 struct gdt_entry {
   uint16_t limitlow;
   uint16_t baselow;
@@ -16,11 +29,13 @@ struct gdt_entry {
   uint8_t basehigh;
 } PACKED;
 
+/* Struct that gets loaded into GDTR */
 struct gdt_ptr {
   uint16_t limit;
   uint64_t base;
 } PACKED;
 
+/* New, extended GDT (we need to extend Limine's GDT) */
 struct gdt_extended {
   struct gdt_entry old[5];
   struct gdt_entry tsslow;

kernel/amd64/hpet.c

@@ -4,95 +4,139 @@
 #include <sync/spin_lock.h>
 #include <sys/debug.h>
 #include <sys/mm.h>
+#include <sys/spin.h>
 #include <uacpi/acpi.h>
 #include <uacpi/status.h>
 #include <uacpi/tables.h>
 #include <uacpi/uacpi.h>
 
-#define HPET_MCVR  0xF0 /* Main Counter Value Register            */
+/*
-#define HPET_GCR   0x10 /* General Configuration Register         */
+ * HPET (High Precision Event Timer) driver code. See more at https://wiki.osdev.org/HPET
-#define HPET_GCIDR 0x00 /* General Capabilities and ID Register   */
+ */
 
+/* HPET Main Counter Value Register */
+#define HPET_MCVR 0xF0
+/* HPET General Configuration Register */
+#define HPET_GCR 0x10
+/* HPET General Capabilities and ID Register */
+#define HPET_GCIDR 0x00
+
+/* Set whether we sould use 32-bit or 64-bit reads/writes */
 static bool hpet_32bits = 1;
+/* Physical address for HPET MMIO */
 static uintptr_t hpet_paddr;
-static uint64_t hpet_clock_nano;
+/* HPET period in femtoseconds */
+static uint64_t hpet_period_fs;
+/* Lock, which protects concurrent access. See amd64/smp.c */
 static spin_lock_t hpet_lock = SPIN_LOCK_INIT;
 
-extern void amd64_spin (void);
+/* Read a HPET register. Assumes caller holds hpet_lock */
-
+static uint64_t amd64_hpet_read64 (uint32_t reg) {
-/* These functions assume hpet_lock is held by the caller! */
-
-static uint64_t amd64_hpet_read (uint32_t reg) {
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
   uintptr_t hpet_vaddr = hpet_paddr + (uintptr_t)hhdm->offset;
-  return (hpet_32bits ? *(volatile uint32_t*)(hpet_vaddr + reg)
+  return *(volatile uint64_t*)(hpet_vaddr + reg);
-                      : *(volatile uint64_t*)(hpet_vaddr + reg));
 }
 
-static void amd64_hpet_write (uint32_t reg, uint64_t value) {
+static uint32_t amd64_hpet_read32 (uint32_t reg) {
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+  uintptr_t hpet_vaddr = hpet_paddr + (uintptr_t)hhdm->offset;
+  return *(volatile uint32_t*)(hpet_vaddr + reg);
+}
+
+/* Write a HPET register. Assumes caller holds hpet_lock */
+static void amd64_hpet_write64 (uint32_t reg, uint64_t value) {
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
   uintptr_t hpet_vaddr = hpet_paddr + (uintptr_t)hhdm->offset;
-  if (hpet_32bits)
-    *(volatile uint32_t*)(hpet_vaddr + reg) = (value & 0xFFFFFFFF);
-  else
   *(volatile uint64_t*)(hpet_vaddr + reg) = value;
 }
 
-static uint64_t amd64_hpet_timestamp (void) { return amd64_hpet_read (HPET_MCVR); }
+static void amd64_hpet_write32 (uint32_t reg, uint32_t value) {
-
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
-uint64_t amd64_hpet_current_nano (bool lock) {
+  uintptr_t hpet_vaddr = hpet_paddr + (uintptr_t)hhdm->offset;
-  if (lock)
+  *(volatile uint32_t*)(hpet_vaddr + reg) = value;
-    spin_lock (&hpet_lock);
-
-  uint64_t t = amd64_hpet_timestamp () * hpet_clock_nano;
-
-  if (lock)
-    spin_unlock (&hpet_lock);
-
-  return t;
 }
 
+/* Read current value of HPET_MCVR register. */
+
+static uint64_t amd64_hpet_read_counter (void) {
+  uint64_t value;
+  spin_lock_ctx_t ctxhrc;
+
+  spin_lock (&hpet_lock, &ctxhrc);
+
+  if (!hpet_32bits)
+    value = amd64_hpet_read64 (HPET_MCVR);
+  else {
+    uint32_t hi1, lo, hi2;
+    do {
+      hi1 = amd64_hpet_read32 (HPET_MCVR + 4);
+      lo = amd64_hpet_read32 (HPET_MCVR + 0);
+      hi2 = amd64_hpet_read32 (HPET_MCVR + 4);
+    } while (hi1 != hi2);
+
+    value = ((uint64_t)hi1 << 32) | lo;
+  }
+
+  spin_unlock (&hpet_lock, &ctxhrc);
+
+  return value;
+}
+
+static void amd64_hpet_write_counter (uint64_t value) {
+  spin_lock_ctx_t ctxhwc;
+
+  spin_lock (&hpet_lock, &ctxhwc);
+
+  if (!hpet_32bits)
+    amd64_hpet_write64 (HPET_MCVR, value);
+  else {
+    amd64_hpet_write32 (HPET_MCVR, (uint32_t)value);
+    amd64_hpet_write32 (HPET_MCVR + 4, (uint32_t)(value >> 32));
+  }
+
+  spin_unlock (&hpet_lock, &ctxhwc);
+}
+
+/* Sleep for a given amount of microseconds. This time can last longer due to \ref hpet_lock being
+ * held. */
 void amd64_hpet_sleep_micro (uint64_t us) {
-  spin_lock (&hpet_lock);
+  if (hpet_period_fs == 0)
+    return;
+
+  uint64_t ticks_to_wait = (us * 1000ULL) / (hpet_period_fs / 1000000ULL);
+  uint64_t start = amd64_hpet_read_counter ();
+
+  for (;;) {
+    uint64_t now = amd64_hpet_read_counter ();
+
+    if ((now - start) >= ticks_to_wait)
+      break;
 
-  uint64_t start = amd64_hpet_timestamp ();
-  uint64_t conv = us * 1000;
-  while (((amd64_hpet_timestamp () - start) * hpet_clock_nano) < conv)
     __asm__ volatile ("pause" ::: "memory");
-
+  }
-  spin_unlock (&hpet_lock);
 }
 
+/* Initialize HPET */
 void amd64_hpet_init (void) {
   struct uacpi_table hpet_table;
   uacpi_status status = uacpi_table_find_by_signature (ACPI_HPET_SIGNATURE, &hpet_table);
   if (status != UACPI_STATUS_OK) {
     DEBUG ("Could not find HPET table!\n");
-    amd64_spin ();
+    spin ();
   }
 
   struct acpi_hpet* hpet = (struct acpi_hpet*)hpet_table.virt_addr;
   hpet_paddr = (uintptr_t)hpet->address.address;
 
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
-  mm_map_kernel_page (hpet_paddr, (uintptr_t)hhdm->offset + hpet_paddr,
+  mm_map_kernel_page (hpet_paddr, (uintptr_t)hhdm->offset + hpet_paddr, MM_PG_PRESENT | MM_PG_RW);
-                      MM_PG_PRESENT | MM_PG_RW | MM_PD_RELOAD);
 
-  hpet_32bits = (amd64_hpet_read (HPET_GCIDR) & (1 << 13)) ? 0 : 1;
+  uint64_t caps = amd64_hpet_read64 (HPET_GCIDR);
+  hpet_32bits = (caps & (1 << 13)) ? 0 : 1;
 
-  /* reset */
+  hpet_period_fs = (uint32_t)(caps >> 32);
-  amd64_hpet_write (HPET_GCR, 0);
-  amd64_hpet_write (HPET_MCVR, 0);
-  amd64_hpet_write (HPET_GCR, 1);
 
-  uint64_t gcidr = amd64_hpet_read (HPET_GCIDR);
+  amd64_hpet_write64 (HPET_GCR, 0);
-  if (hpet_32bits) {
+  amd64_hpet_write_counter (0);
-    uint32_t low = (uint32_t)gcidr;
+  amd64_hpet_write64 (HPET_GCR, 1);
-    uint32_t high = (uint32_t)amd64_hpet_read (HPET_GCIDR + 4);
-    gcidr = (((uint64_t)high << 32) | low);
-  }
-
-  uint64_t period_fs = (gcidr >> 32);
-
-  hpet_clock_nano = period_fs / 1000000;
 }

kernel/amd64/hpet.h

@@ -3,7 +3,6 @@
 
 #include <libk/std.h>
 
-uint64_t amd64_hpet_current_nano (bool lock);
 void amd64_hpet_sleep_micro (uint64_t us);
 void amd64_hpet_init (void);
 

kernel/amd64/init.c

@@ -1,3 +1,4 @@
+#include <amd64/gdt.h>
 #include <amd64/init.h>
 #include <amd64/intr.h>
 #include <amd64/smp.h>
@@ -5,15 +6,10 @@
 #include <libk/std.h>
 #include <libk/string.h>
 
-#define GDT_KCODE 0x08
-#define GDT_KDATA 0x10
-#define GDT_UCODE 0x18
-#define GDT_UDATA 0x20
-#define GDT_TSS   0x28
-
 #define TSS         0x80
 #define TSS_PRESENT 0x89
 
+/* Set a GDT entry */
 static void amd64_gdt_set (volatile struct gdt_entry* ent, uint32_t base, uint32_t limit,
                            uint8_t acc, uint8_t gran) {
   ent->baselow = (base & 0xFFFF);
@@ -24,6 +20,7 @@ static void amd64_gdt_set (volatile struct gdt_entry* ent, uint32_t base, uint32
   ent->access = acc;
 }
 
+/* Initialize GDT and TSS structures for a given CPU */
 static void amd64_gdt_init (struct cpu* cpu) {
   volatile struct tss* tss = &cpu->tss;
   volatile struct gdt_extended* gdt = &cpu->gdt;
@@ -42,8 +39,8 @@ static void amd64_gdt_init (struct cpu* cpu) {
   amd64_gdt_set (&gdt->old[0], 0, 0, 0, 0);
   amd64_gdt_set (&gdt->old[1], 0, 0xFFFFF, 0x9A, 0xA0);
   amd64_gdt_set (&gdt->old[2], 0, 0xFFFFF, 0x92, 0xC0);
-  amd64_gdt_set (&gdt->old[3], 0, 0xFFFFF, 0xFA, 0xA0);
+  amd64_gdt_set (&gdt->old[3], 0, 0xFFFFF, 0xF2, 0xC0);
-  amd64_gdt_set (&gdt->old[4], 0, 0xFFFFF, 0xF2, 0xC0);
+  amd64_gdt_set (&gdt->old[4], 0, 0xFFFFF, 0xFA, 0xA0);
   amd64_gdt_set (&gdt->tsslow, (tssbase & 0xFFFFFFFF), tsslimit, TSS_PRESENT | TSS, 0);
 
   uint32_t tssbasehigh = (tssbase >> 32);
@@ -54,11 +51,13 @@ static void amd64_gdt_init (struct cpu* cpu) {
   gdt->tsshigh.access = 0;
   gdt->tsshigh.gran = 0;
 
+  /* Load GDTR */
   struct gdt_ptr gdtr;
   gdtr.limit = sizeof (*gdt) - 1;
   gdtr.base = (uint64_t)gdt;
   __asm__ volatile ("lgdt %0" ::"m"(gdtr) : "memory");
 
+  /* Reload CS */
   __asm__ volatile ("pushq %[kcode]\n"
                     "lea 1f(%%rip), %%rax\n"
                     "pushq %%rax\n"
@@ -75,6 +74,12 @@ static void amd64_gdt_init (struct cpu* cpu) {
   __asm__ volatile ("ltr %0" ::"r"((uint16_t)GDT_TSS));
 }
 
+/*
+ * Initialize essentials (GDT, TSS, IDT) for a given CPU
+ *
+ * load_idt - Tell whether the IDT needs to be loaded. It only has to be loaded once on
+ *  the BSP
+ */
 void amd64_init (struct cpu* cpu, bool load_idt) {
   amd64_gdt_init (cpu);
   if (load_idt)

kernel/amd64/intr.c

@@ -1,4 +1,5 @@
 #include <amd64/apic.h>
+#include <amd64/gdt.h>
 #include <amd64/intr.h>
 #include <amd64/intr_defs.h>
 #include <amd64/io.h>
@@ -6,9 +7,12 @@
 #include <irq/irq.h>
 #include <libk/std.h>
 #include <libk/string.h>
+#include <m/syscall_defs.h>
 #include <sys/debug.h>
 #include <sys/irq.h>
 #include <sys/smp.h>
+#include <sys/spin.h>
+#include <syscall/syscall.h>
 
 /* 8259 PIC defs. */
 #define PIC1      0x20
@@ -37,6 +41,7 @@
 
 #define IDT_ENTRIES_MAX 256
 
+/* 64-bit <IDT entry structure: https://wiki.osdev.org/Interrupt_Descriptor_Table */
 struct idt_entry {
   uint16_t intrlow;
   uint16_t kernel_cs;
@@ -55,8 +60,6 @@ struct idt {
 ALIGNED (16) static volatile struct idt_entry idt_entries[IDT_ENTRIES_MAX];
 static volatile struct idt idt;
 
-extern void amd64_spin (void);
-
 /* Remaps and disables old 8259 PIC, since we'll be using APIC. */
 static void amd64_init_pic (void) {
 #define IO_OP(fn, ...)                                                                             \
@@ -82,10 +85,11 @@ static void amd64_init_pic (void) {
 #undef IO_OP
 }
 
+/* Set IDT entry */
 static void amd64_idt_set (volatile struct idt_entry* ent, uint64_t handler, uint8_t flags,
                            uint8_t ist) {
   ent->intrlow = (handler & 0xFFFF);
-  ent->kernel_cs = 0x08; // GDT_KCODE (init.c)
+  ent->kernel_cs = GDT_KCODE;
   ent->ist = ist;
   ent->attrs = flags;
   ent->intrmid = ((handler >> 16) & 0xFFFF);
@@ -93,8 +97,10 @@ static void amd64_idt_set (volatile struct idt_entry* ent, uint64_t handler, uin
   ent->resv = 0;
 }
 
+/* Load the IDT */
 void amd64_load_idt (void) { __asm__ volatile ("lidt %0" ::"m"(idt)); }
 
+/* Initialize IDT entries */
 static void amd64_idt_init (void) {
   memset ((void*)idt_entries, 0, sizeof (idt_entries));
 
@@ -117,6 +123,8 @@ static void amd64_idt_init (void) {
 
   IDT_ENTRY (SCHED_PREEMPT_TIMER, 1);
   IDT_ENTRY (TLB_SHOOTDOWN, 1);
+  IDT_ENTRY (CPU_REQUEST_SCHED, 1);
+  IDT_ENTRY (CPU_SPURIOUS, 1);
   /* clang-format on */
 #undef IDT_ENTRY
 
@@ -126,6 +134,7 @@ static void amd64_idt_init (void) {
   amd64_load_idt ();
 }
 
+/* Handle CPU exception and dump registers. If incoming CS has CPL3, kill the process. */
 static void amd64_intr_exception (struct saved_regs* regs) {
   DEBUG ("cpu exception %lu (%lu)\n", regs->trap, regs->error);
 
@@ -147,16 +156,30 @@ static void amd64_intr_exception (struct saved_regs* regs) {
                regs->error, regs->rip, regs->cs, regs->rflags, regs->rsp, regs->ss, cr2, cr3,
                regs->rbx);
 
-  if (regs->cs == (0x18 | 0x03)) {
+  if (regs->cs == (GDT_UCODE | 0x03)) {
     proc_kill (thiscpu->proc_current);
   } else {
-    amd64_spin ();
+    spin ();
   }
 }
 
+/* Handle incoming interrupt, dispatch IRQ handlers. */
 void amd64_intr_handler (void* stack_ptr) {
+  spin_lock_ctx_t ctxcpu, ctxpr;
+
+  amd64_load_kernel_cr3 ();
+
   struct saved_regs* regs = stack_ptr;
 
+  spin_lock (&thiscpu->lock, &ctxcpu);
+  struct proc* proc_current = thiscpu->proc_current;
+  spin_lock (&proc_current->lock, &ctxpr);
+
+  memcpy (&proc_current->pdata.regs, regs, sizeof (struct saved_regs));
+
+  spin_unlock (&proc_current->lock, &ctxpr);
+  spin_unlock (&thiscpu->lock, &ctxcpu);
+
   if (regs->trap <= 31) {
     amd64_intr_exception (regs);
   } else {
@@ -165,17 +188,12 @@ void amd64_intr_handler (void* stack_ptr) {
     struct irq* irq = irq_find (regs->trap);
 
     if (irq != NULL) {
-      if (!(irq->flags & IRQ_INTERRUPT_SAFE))
-        __asm__ volatile ("sti");
-
       irq->func (irq->arg, stack_ptr);
-
-      if (!(irq->flags & IRQ_INTERRUPT_SAFE))
-        __asm__ volatile ("cli");
     }
   }
 }
 
+/* Initialize interrupts */
 void amd64_intr_init (void) {
   amd64_init_pic ();
   amd64_idt_init ();
@@ -183,42 +201,21 @@ void amd64_intr_init (void) {
 
 /* Aux. */
 
+/* Save RFLAGS of the current CPU */
 static uint64_t amd64_irq_save_flags (void) {
   uint64_t rflags;
   __asm__ volatile ("pushfq; cli; popq %0" : "=r"(rflags)::"memory", "cc");
   return rflags;
 }
 
+/* Restore interrupts (IF bit) from RFLAGS */
 static void amd64_irq_restore_flags (uint64_t rflags) {
   if (rflags & (1ULL << 9))
     __asm__ volatile ("sti");
 }
 
-void irq_save (void) {
+/* Save current interrupt state */
-  /* before smp init. */
+void irq_save (spin_lock_ctx_t* ctx) { *ctx = amd64_irq_save_flags (); }
-  if (thiscpu == NULL)
-    return;
 
-  int prev = atomic_fetch_add_explicit (&thiscpu->irq_ctx.nesting, 1, memory_order_acq_rel);
+/* Restore interrupt state */
-  if (prev == 0)
+void irq_restore (spin_lock_ctx_t* ctx) { amd64_irq_restore_flags (*ctx); }
-    thiscpu->irq_ctx.rflags = amd64_irq_save_flags ();
-}
-
-void irq_restore (void) {
-  /* before smp init. */
-  if (thiscpu == NULL)
-    return;
-
-  int prev = atomic_fetch_sub_explicit (&thiscpu->irq_ctx.nesting, 1, memory_order_acq_rel);
-  if (prev == 1)
-    amd64_irq_restore_flags (thiscpu->irq_ctx.rflags);
-}
-
-uint8_t amd64_resolve_irq (uint8_t irq) {
-  static const uint8_t mappings[] = {
-      [SCHED_PREEMPT_TIMER] = 0,
-      [TLB_SHOOTDOWN] = 1,
-  };
-
-  return mappings[irq];
-}

kernel/amd64/intr.h

@@ -32,7 +32,6 @@ struct saved_regs {
 } PACKED;
 
 void amd64_load_idt (void);
-uint8_t amd64_resolve_irq (uint8_t irq);
 void amd64_intr_init (void);
 
 #endif // _KERNEL_AMD64_INTR_H

kernel/amd64/intr_defs.h

@@ -1,7 +1,12 @@
 #ifndef _KERNEL_AMD64_INTR_DEFS_H
 #define _KERNEL_AMD64_INTR_DEFS_H
 
+/* Definitions for custom, nonstandard IDT entries. They have to be remapped by amd64_resolve_irq
+ * into legacy IRQs. */
+
 #define SCHED_PREEMPT_TIMER 80
 #define TLB_SHOOTDOWN       81
+#define CPU_REQUEST_SCHED   82
+#define CPU_SPURIOUS        255
 
 #endif // _KERNEL_AMD64_INTR_DEFS_H

kernel/amd64/intr_stub.S

@@ -1,4 +1,5 @@
 #include <amd64/intr_defs.h>
+#include <amd64/regsasm.h>
 
 .extern amd64_intr_handler
 
@@ -9,56 +10,38 @@
   pushq $0;       \
   pushq $z;
 
-#define push_regs \
-  pushq %rax; \
-  pushq %rcx; \
-  pushq %rdx; \
-  pushq %rsi; \
-  pushq %rdi; \
-  pushq %rbp; \
-  pushq %rbx; \
-  pushq %r8; \
-  pushq %r9; \
-  pushq %r10; \
-  pushq %r11; \
-  pushq %r12; \
-  pushq %r13; \
-  pushq %r14; \
-  pushq %r15;
-
-#define pop_regs \
-  popq %r15; \
-  popq %r14; \
-  popq %r13; \
-  popq %r12; \
-  popq %r11; \
-  popq %r10; \
-  popq %r9; \
-  popq %r8; \
-  popq %rbx; \
-  popq %rbp; \
-  popq %rdi; \
-  popq %rsi; \
-  popq %rdx; \
-  popq %rcx; \
-  popq %rax;
-
 #define make_intr_stub(x, n)    \
   .global amd64_intr ## n;      \
   amd64_intr ## n:;             \
   x(n);                         \
   cli;                          \
+  ;                             \
   push_regs;                    \
+  ;                             \
+  movw $0x10, %ax;              \
+  movw %ax, %ds;                \
+  movw %ax, %es;                \
+  ;                             \
   cld;                          \
+  ;                             \
   movq %rsp, %rdi;              \
-  movq %rsp, %rax; \
+  ;                             \
+  movq %cr3, %rax; pushq %rax;  \
+  ;                             \
+  movq %rsp, %rbp;              \
+  ;                             \
   subq $8, %rsp;                \
-  andq $~0xF, %rsp; \
+  andq $-16, %rsp;              \
-  movq %rax, (%rsp); \
+  ;                             \
   callq amd64_intr_handler;     \
-  movq (%rsp), %rsp; \
+  ;                             \
+  movq %rbp, %rsp;              \
+  ;                             \
+  popq %rax; movq %rax, %cr3;   \
+  ;                             \
   pop_regs;                     \
   addq $16, %rsp;               \
+  ;                             \
   iretq;
   
 
@@ -113,3 +96,5 @@ make_intr_stub(no_err, 47)
 
 make_intr_stub(no_err, SCHED_PREEMPT_TIMER)
 make_intr_stub(no_err, TLB_SHOOTDOWN)
+make_intr_stub(no_err, CPU_REQUEST_SCHED)
+make_intr_stub(no_err, CPU_SPURIOUS)

kernel/amd64/io.c

@@ -1,42 +1,51 @@
 #include <amd64/io.h>
 #include <libk/std.h>
 
+/// Perform outb instruction (send 8-bit int)
 void amd64_io_outb (uint16_t port, uint8_t v) {
   __asm__ volatile ("outb %1, %0" ::"dN"(port), "a"(v));
 }
 
+/// Perform outw instruction (send 16-bit int)
 void amd64_io_outw (uint16_t port, uint16_t v) {
   __asm__ volatile ("outw %%ax, %%dx" ::"a"(v), "d"(port));
 }
 
+/// Perform outl instruction (send 32-bit int)
 void amd64_io_outl (uint16_t port, uint32_t v) {
   __asm__ volatile ("outl %%eax, %%dx" ::"d"(port), "a"(v));
 }
 
+/// Perform outsw instruction (send a string)
 void amd64_io_outsw (uint16_t port, const void* addr, int cnt) {
   __asm__ volatile ("cld; rep outsw" : "+S"(addr), "+c"(cnt) : "d"(port) : "memory", "cc");
 }
 
+/// Perform inb instruction (receive 8-bit int)
 uint8_t amd64_io_inb (uint16_t port) {
   uint8_t r;
   __asm__ volatile ("inb %1, %0" : "=a"(r) : "dN"(port));
   return r;
 }
 
+/// Perform inw instruction (receive 16-bit int)
 uint16_t amd64_io_inw (uint16_t port) {
   uint16_t r;
   __asm__ volatile ("inw %%dx, %%ax" : "=a"(r) : "d"(port));
   return r;
 }
 
+/// Perform inl instruction (receive 32-bit int)
 uint32_t amd64_io_inl (uint16_t port) {
   uint32_t r;
   __asm__ volatile ("inl %%dx, %%eax" : "=a"(r) : "d"(port));
   return r;
 }
 
+/// Perform insw instruction (receive a string)
 void amd64_io_insw (uint16_t port, void* addr, int cnt) {
   __asm__ volatile ("cld; rep insw" : "+D"(addr), "+c"(cnt) : "d"(port) : "memory", "cc");
 }
 
+/// output a byte on port 0x80, which does a small IO delay
 void amd64_io_wait (void) { amd64_io_outb (0x80, 0); }

kernel/amd64/mm.c

@@ -14,25 +14,40 @@
 #define AMD64_PG_PRESENT (1 << 0)
 #define AMD64_PG_RW      (1 << 1)
 #define AMD64_PG_USER    (1 << 2)
+#define AMD64_PG_HUGE    (1 << 7)
 
+/* Auxilary struct for page directory walking */
 struct pg_index {
   uint16_t pml4, pml3, pml2, pml1;
 } PACKED;
 
-static struct pd kernel_pd = {.lock = SPIN_LOCK_INIT};
+/* Kernel page directory */
-/* This is needed to sync between map/unmap operations and TLB shootdown. */
+static struct pd kernel_pd;
-static spin_lock_t mm_lock = SPIN_LOCK_INIT;
+static spin_lock_t kernel_pd_lock;
 
+void mm_kernel_lock (spin_lock_ctx_t* ctx) { spin_lock (&kernel_pd_lock, ctx); }
+
+void mm_kernel_unlock (spin_lock_ctx_t* ctx) { spin_lock (&kernel_pd_lock, ctx); }
+
+/* Get current value of CR3 register */
 static uintptr_t amd64_current_cr3 (void) {
   uintptr_t cr3;
   __asm__ volatile ("movq %%cr3, %0" : "=r"(cr3)::"memory");
   return cr3;
 }
 
+/* Load kernel CR3 as current CR3 */
 void amd64_load_kernel_cr3 (void) {
+  uintptr_t cr3 = amd64_current_cr3 ();
+
+  if (cr3 != kernel_pd.cr3_paddr) {
     __asm__ volatile ("movq %0, %%cr3" ::"r"(kernel_pd.cr3_paddr) : "memory");
   }
+}
 
+struct pd* mm_get_kernel_pd (void) { return &kernel_pd; }
+
+/* Extract PML info from virtual address */
 static struct pg_index amd64_mm_page_index (uint64_t vaddr) {
   struct pg_index ret;
 
@@ -44,15 +59,19 @@ static struct pg_index amd64_mm_page_index (uint64_t vaddr) {
   return ret;
 }
 
+/* Walk paging tables and allocate necessary structures along the way */
 static uint64_t* amd64_mm_next_table (uint64_t* table, uint64_t entry_idx, bool alloc) {
   uint64_t entry = table[entry_idx];
   physaddr_t paddr;
 
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
 
-  if (entry & AMD64_PG_PRESENT)
+  if (entry & AMD64_PG_PRESENT) {
+    if (entry & AMD64_PG_HUGE)
+      return NULL;
+
     paddr = entry & ~0xFFFULL;
-  else {
+  } else {
     if (!alloc)
       return NULL;
 
@@ -68,6 +87,15 @@ static uint64_t* amd64_mm_next_table (uint64_t* table, uint64_t entry_idx, bool
   return (uint64_t*)((uintptr_t)hhdm->offset + (uintptr_t)paddr);
 }
 
+static bool amd64_mm_is_table_empty (uint64_t* table) {
+  for (size_t i = 0; i < 512; i++) {
+    if (table[i] & AMD64_PG_PRESENT)
+      return false;
+  }
+  return true;
+}
+
+/* Convert generic memory management subsystem flags into AMD64-specific flags */
 static uint64_t amd64_mm_resolve_flags (uint32_t generic) {
   uint64_t flags = 0;
 
@@ -78,19 +106,15 @@ static uint64_t amd64_mm_resolve_flags (uint32_t generic) {
   return flags;
 }
 
+/* Reload the current CR3 value ON A LOCAL CPU */
 static void amd64_reload_cr3 (void) {
   uint64_t cr3;
   __asm__ volatile ("movq %%cr3, %0; movq %0, %%cr3" : "=r"(cr3)::"memory");
 }
 
+/* Map physical address to virtual address with flags. TLB needs to be flushed afterwards. */
 void mm_map_page (struct pd* pd, uintptr_t paddr, uintptr_t vaddr, uint32_t flags) {
-  spin_lock (&mm_lock);
-
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
-  bool do_reload = false;
-
-  if (flags & MM_PD_LOCK)
-    spin_lock (&pd->lock);
 
   uint64_t amd64_flags = amd64_mm_resolve_flags (flags);
 
@@ -99,82 +123,77 @@ void mm_map_page (struct pd* pd, uintptr_t paddr, uintptr_t vaddr, uint32_t flag
 
   uint64_t* pml3 = amd64_mm_next_table (pml4, pg_index.pml4, true);
   if (pml3 == NULL)
-    goto done;
+    return;
 
   uint64_t* pml2 = amd64_mm_next_table (pml3, pg_index.pml3, true);
   if (pml2 == NULL)
-    goto done;
+    return;
 
   uint64_t* pml1 = amd64_mm_next_table (pml2, pg_index.pml2, true);
   if (pml1 == NULL)
-    goto done;
+    return;
 
   uint64_t* pte = &pml1[pg_index.pml1];
 
   *pte = ((paddr & ~0xFFFULL) | (amd64_flags & 0x7ULL));
-  do_reload = true;
-
-done:
-  if (do_reload && (flags & MM_PD_RELOAD))
-    amd64_reload_cr3 ();
-
-  if (flags & MM_PD_LOCK)
-    spin_unlock (&pd->lock);
-
-  spin_unlock (&mm_lock);
 }
 
+/* Map a page into kernel page directory */
 void mm_map_kernel_page (uintptr_t paddr, uintptr_t vaddr, uint32_t flags) {
   mm_map_page (&kernel_pd, paddr, vaddr, flags);
+  amd64_reload_cr3 ();
 }
 
-void mm_unmap_page (struct pd* pd, uintptr_t vaddr, uint32_t flags) {
+/* Unmap a virtual address. TLB needs to be flushed afterwards */
-  spin_lock (&mm_lock);
+void mm_unmap_page (struct pd* pd, uintptr_t vaddr) {
-
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
-  bool do_reload = false;
-
-  if (flags & MM_PD_LOCK)
-    spin_lock (&pd->lock);
 
   uint64_t* pml4 = (uint64_t*)(pd->cr3_paddr + (uintptr_t)hhdm->offset);
   struct pg_index pg_index = amd64_mm_page_index (vaddr);
 
   uint64_t* pml3 = amd64_mm_next_table (pml4, pg_index.pml4, false);
   if (pml3 == NULL)
-    goto done;
+    return;
 
   uint64_t* pml2 = amd64_mm_next_table (pml3, pg_index.pml3, false);
   if (pml2 == NULL)
-    goto done;
+    return;
 
   uint64_t* pml1 = amd64_mm_next_table (pml2, pg_index.pml2, false);
   if (pml1 == NULL)
-    goto done;
+    return;
 
   uint64_t* pte = &pml1[pg_index.pml1];
 
-  *pte &= ~AMD64_PG_PRESENT;
+  if ((*pte) & AMD64_PG_PRESENT)
-  do_reload = true;
+    *pte = 0;
 
-done:
+  if (amd64_mm_is_table_empty (pml1)) {
-  if (do_reload && (flags & MM_PD_RELOAD))
+    uintptr_t pml1_phys = pml2[pg_index.pml2] & ~0xFFFULL;
+    pmm_free (pml1_phys, 1);
+    pml2[pg_index.pml2] = 0;
+
+    if (amd64_mm_is_table_empty (pml2)) {
+      uintptr_t pml2_phys = pml3[pg_index.pml3] & ~0xFFFULL;
+      pmm_free (pml2_phys, 1);
+      pml3[pg_index.pml3] = 0;
+
+      if (amd64_mm_is_table_empty (pml3)) {
+        uintptr_t pml3_phys = pml4[pg_index.pml4] & ~0xFFFULL;
+        pmm_free (pml3_phys, 1);
+        pml4[pg_index.pml4] = 0;
+      }
+    }
+  }
+}
+
+/* Unmap a page from kernel page directory */
+void mm_unmap_kernel_page (uintptr_t vaddr) {
+  mm_unmap_page (&kernel_pd, vaddr);
   amd64_reload_cr3 ();
-
-  if (flags & MM_PD_LOCK)
-    spin_unlock (&pd->lock);
-
-  spin_unlock (&mm_lock);
 }
 
-void mm_unmap_kernel_page (uintptr_t vaddr, uint32_t flags) {
+/* Allocate a userspace-ready page directory */
-  mm_unmap_page (&kernel_pd, vaddr, flags);
-}
-
-void mm_lock_kernel (void) { spin_lock (&kernel_pd.lock); }
-
-void mm_unlock_kernel (void) { spin_unlock (&kernel_pd.lock); }
-
 uintptr_t mm_alloc_user_pd_phys (void) {
   struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
 
@@ -192,27 +211,111 @@ uintptr_t mm_alloc_user_pd_phys (void) {
   return cr3;
 }
 
-void mm_reload (void) {
+bool mm_validate (struct pd* pd, uintptr_t vaddr) {
-  spin_lock (&mm_lock);
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+  bool ret = false;
 
-  struct limine_mp_response* mp = limine_mp_request.response;
+  uint64_t* pml4 = (uint64_t*)(pd->cr3_paddr + (uintptr_t)hhdm->offset);
+  struct pg_index pg_index = amd64_mm_page_index (vaddr);
 
-  for (size_t i = 0; i < mp->cpu_count; i++) {
+  uint64_t* pml3 = amd64_mm_next_table (pml4, pg_index.pml4, false);
-    amd64_lapic_ipi (mp->cpus[i]->lapic_id, TLB_SHOOTDOWN);
+  if (pml3 == NULL)
+    goto done;
+
+  uint64_t* pml2 = amd64_mm_next_table (pml3, pg_index.pml3, false);
+  if (pml2 == NULL)
+    goto done;
+
+  uint64_t* pml1 = amd64_mm_next_table (pml2, pg_index.pml2, false);
+  if (pml1 == NULL)
+    goto done;
+
+  uint64_t pte = pml1[pg_index.pml1];
+  ret = (pte & AMD64_PG_PRESENT) != 0;
+
+done:
+  return ret;
 }
 
-  spin_unlock (&mm_lock);
+bool mm_validate_buffer (struct pd* pd, uintptr_t vaddr, size_t size) {
+  bool ok = true;
+
+  for (size_t i = 0; i < size; i++) {
+    ok = mm_validate (pd, vaddr + i);
+    if (!ok)
+      goto done;
   }
 
-static void amd64_tlb_shootdown_irq (void* arg, void* regs) {
+done:
-  (void)arg, (void)regs;
+  return ok;
-
-  amd64_reload_cr3 ();
-  DEBUG ("cpu %u TLB shootdown\n", thiscpu->id);
 }
 
-void mm_init2 (void) {
+uintptr_t mm_p2v (struct pd* pd, uintptr_t paddr) {
-  irq_attach (&amd64_tlb_shootdown_irq, NULL, TLB_SHOOTDOWN, IRQ_INTERRUPT_SAFE);
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+  uintptr_t ret = 0;
+
+  uint64_t* pml4 = (uint64_t*)(pd->cr3_paddr + (uintptr_t)hhdm->offset);
+
+  for (size_t i4 = 0; i4 < 512; i4++) {
+    if (!(pml4[i4] & AMD64_PG_PRESENT))
+      continue;
+
+    uint64_t* pml3 = (uint64_t*)((uintptr_t)hhdm->offset + (pml4[i4] & ~0xFFFULL));
+    for (size_t i3 = 0; i3 < 512; i3++) {
+      if (!(pml3[i3] & AMD64_PG_PRESENT))
+        continue;
+
+      uint64_t* pml2 = (uint64_t*)((uintptr_t)hhdm->offset + (pml3[i3] & ~0xFFFULL));
+      for (size_t i2 = 0; i2 < 512; i2++) {
+        if (!(pml2[i2] & AMD64_PG_PRESENT))
+          continue;
+
+        uint64_t* pml1 = (uint64_t*)((uintptr_t)hhdm->offset + (pml2[i2] & ~0xFFFULL));
+        for (size_t i1 = 0; i1 < 512; i1++) {
+          if ((pml1[i1] & AMD64_PG_PRESENT) && ((pml1[i1] & ~0xFFFULL) == (paddr & ~0xFFFULL))) {
+            struct pg_index idx = {i4, i3, i2, i1};
+            ret = (((uint64_t)idx.pml4 << 39) | ((uint64_t)idx.pml3 << 30) |
+                   ((uint64_t)idx.pml2 << 21) | ((uint64_t)idx.pml1 << 12) | (paddr & 0xFFFULL));
+            goto done;
+          }
+        }
+      }
+    }
   }
 
+done:
+  return ret;
+}
+
+uintptr_t mm_v2p (struct pd* pd, uintptr_t vaddr) {
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+  uintptr_t ret = 0;
+
+  uint64_t* pml4 = (uint64_t*)(pd->cr3_paddr + (uintptr_t)hhdm->offset);
+  struct pg_index pg_index = amd64_mm_page_index (vaddr);
+
+  uint64_t* pml3 = amd64_mm_next_table (pml4, pg_index.pml4, false);
+  if (pml3 == NULL)
+    goto done;
+
+  uint64_t* pml2 = amd64_mm_next_table (pml3, pg_index.pml3, false);
+  if (pml2 == NULL)
+    goto done;
+
+  uint64_t* pml1 = amd64_mm_next_table (pml2, pg_index.pml2, false);
+  if (pml1 == NULL)
+    goto done;
+
+  uint64_t pte = pml1[pg_index.pml1];
+
+  if (!(pte & AMD64_PG_PRESENT))
+    goto done;
+
+  ret = ((pte & ~0xFFFULL) | (vaddr & 0xFFFULL));
+
+done:
+  return ret;
+}
+
+/* Initialize essentials for the AMD64 memory management subsystem */
 void mm_init (void) { kernel_pd.cr3_paddr = amd64_current_cr3 (); }

kernel/amd64/mm.h

@@ -7,11 +7,9 @@
 #define PAGE_SIZE 4096
 
 struct pd {
-  spin_lock_t lock;
   uintptr_t cr3_paddr;
 };
 
 void amd64_load_kernel_cr3 (void);
-void mm_init2 (void);
 
 #endif // _KERNEL_AMD64_MM_H

kernel/amd64/msr-index.h

@@ -85,7 +85,7 @@ patent must be licensed for everyone's free use or not licensed at all.
 
   The precise terms and conditions for copying, distribution and
 modification follow.
-
+
         GNU GENERAL PUBLIC LICENSE
    TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
 
@@ -140,7 +140,7 @@ above, provided that you also meet all of these conditions:
     License.  (Exception: if the Program itself is interactive but
     does not normally print such an announcement, your work based on
     the Program is not required to print an announcement.)
-
+
 These requirements apply to the modified work as a whole.  If
 identifiable sections of that work are not derived from the Program,
 and can be reasonably considered independent and separate works in
@@ -198,7 +198,7 @@ access to copy from a designated place, then offering equivalent
 access to copy the source code from the same place counts as
 distribution of the source code, even though third parties are not
 compelled to copy the source along with the object code.
-
+
   4. You may not copy, modify, sublicense, or distribute the Program
 except as expressly provided under this License.  Any attempt
 otherwise to copy, modify, sublicense or distribute the Program is
@@ -255,7 +255,7 @@ impose that choice.
 
 This section is intended to make thoroughly clear what is believed to
 be a consequence of the rest of this License.
-
+
   8. If the distribution and/or use of the Program is restricted in
 certain countries either by patents or by copyrighted interfaces, the
 original copyright holder who places the Program under this License
@@ -308,7 +308,7 @@ PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGES.
 
          END OF TERMS AND CONDITIONS
-
+
       How to Apply These Terms to Your New Programs
 
   If you develop a new program, and you want it to be of the greatest

kernel/amd64/msr.c

@@ -1,12 +1,14 @@
 #include <amd64/msr.h>
 #include <libk/std.h>
 
+/// Read a model-specific register
 uint64_t amd64_rdmsr (uint32_t msr) {
   uint32_t low, high;
   __asm__ volatile ("rdmsr" : "=a"(low), "=d"(high) : "c"(msr));
   return ((uint64_t)high << 32 | (uint64_t)low);
 }
 
+/// Write a model-specific register
 void amd64_wrmsr (uint32_t msr, uint64_t value) {
   uint32_t low = (uint32_t)(value & 0xFFFFFFFF);
   uint32_t high = (uint32_t)(value >> 32);

kernel/amd64/msr.h

@@ -3,9 +3,6 @@
 
 #include <libk/std.h>
 
-#define MSR_FS_BASE 0xC0000100
-#define MSR_GS_BASE 0xC0000101
-
 uint64_t amd64_rdmsr (uint32_t msr);
 void amd64_wrmsr (uint32_t msr, uint64_t value);
 

kernel/amd64/proc.c

@@ -0,0 +1,138 @@
+#include <amd64/gdt.h>
+#include <amd64/proc.h>
+#include <aux/elf.h>
+#include <libk/align.h>
+#include <libk/list.h>
+#include <libk/rbtree.h>
+#include <libk/std.h>
+#include <libk/string.h>
+#include <limine/requests.h>
+#include <mm/liballoc.h>
+#include <mm/pmm.h>
+#include <proc/mutex.h>
+#include <proc/proc.h>
+#include <proc/procgroup.h>
+#include <proc/resource.h>
+#include <sync/spin_lock.h>
+#include <sys/debug.h>
+#include <sys/proc.h>
+
+static atomic_int pids = 0;
+
+struct proc* proc_from_elf (uint8_t* elf_contents) {
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+
+  struct proc* proc = malloc (sizeof (*proc));
+  if (proc == NULL)
+    return NULL;
+
+  memset (proc, 0, sizeof (*proc));
+
+  proc->lock = SPIN_LOCK_INIT;
+  atomic_store (&proc->state, PROC_READY);
+  proc->pid = atomic_fetch_add (&pids, 1);
+
+  proc->procgroup = procgroup_create ();
+  if (proc->procgroup == NULL) {
+    free (proc);
+    return NULL;
+  }
+  procgroup_attach (proc->procgroup, proc);
+
+  uintptr_t kstack_paddr = pmm_alloc (KSTACK_SIZE / PAGE_SIZE);
+  proc->pdata.kernel_stack = kstack_paddr + (uintptr_t)hhdm->offset + KSTACK_SIZE;
+
+  procgroup_map (proc->procgroup, PROC_USTACK_TOP - USTACK_SIZE, USTACK_SIZE / PAGE_SIZE,
+                 MM_PG_USER | MM_PG_PRESENT | MM_PG_RW, NULL);
+
+  proc->flags |= PROC_USTK_PREALLOC;
+
+  struct elf_aux aux = proc_load_segments (proc, elf_contents);
+
+  proc->pdata.regs.ss = GDT_UDATA | 0x03;
+  proc->pdata.regs.rsp = (uint64_t)PROC_USTACK_TOP;
+  proc->pdata.regs.rflags = 0x202;
+  proc->pdata.regs.cs = GDT_UCODE | 0x03;
+  proc->pdata.regs.rip = aux.entry;
+
+  return proc;
+}
+
+struct proc* proc_clone (struct proc* proto, uintptr_t vstack_top, uintptr_t entry,
+                         uintptr_t argument_ptr) {
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+  spin_lock_ctx_t ctxprt;
+
+  struct proc* proc = malloc (sizeof (*proc));
+  if (proc == NULL)
+    return NULL;
+
+  memset (proc, 0, sizeof (*proc));
+
+  proc->lock = SPIN_LOCK_INIT;
+  atomic_store (&proc->state, PROC_READY);
+  proc->pid = atomic_fetch_add (&pids, 1);
+
+  spin_lock (&proto->lock, &ctxprt);
+
+  proc->procgroup = proto->procgroup;
+  procgroup_attach (proc->procgroup, proc);
+
+  spin_unlock (&proto->lock, &ctxprt);
+
+  uintptr_t kstack_paddr = pmm_alloc (KSTACK_SIZE / PAGE_SIZE);
+  proc->pdata.kernel_stack = kstack_paddr + (uintptr_t)hhdm->offset + KSTACK_SIZE;
+
+  proc->pdata.regs.ss = GDT_UDATA | 0x03;
+  proc->pdata.regs.rsp = (uint64_t)vstack_top;
+  proc->pdata.regs.rflags = 0x202;
+  proc->pdata.regs.cs = GDT_UCODE | 0x03;
+  proc->pdata.regs.rip = (uint64_t)entry;
+
+  proc->uvaddr_argument = argument_ptr;
+
+  proc_init_tls (proc);
+
+  return proc;
+}
+
+void proc_cleanup (struct proc* proc) {
+  proc_sqs_cleanup (proc);
+  proc_mutexes_cleanup (proc);
+
+  pmm_free (proc->pdata.kernel_stack, KSTACK_SIZE / PAGE_SIZE);
+  procgroup_unmap (proc->procgroup, proc->pdata.tls_vaddr, proc->procgroup->tls.tls_tmpl_pages);
+
+  procgroup_detach (proc->procgroup, proc);
+
+  /* clean the process */
+  free (proc);
+}
+
+void proc_init_tls (struct proc* proc) {
+  struct limine_hhdm_response* hhdm = limine_hhdm_request.response;
+
+  if (proc->procgroup->tls.tls_tmpl == NULL)
+    return;
+
+  size_t tls_size = proc->procgroup->tls.tls_tmpl_size;
+  size_t pages = proc->procgroup->tls.tls_tmpl_pages;
+
+  uintptr_t tls_paddr;
+  uint32_t flags = MM_PG_USER | MM_PG_PRESENT | MM_PG_RW;
+
+  uintptr_t tls_vaddr = procgroup_map (proc->procgroup, 0, pages, flags, &tls_paddr);
+
+  uintptr_t k_tls_addr = (uintptr_t)hhdm->offset + tls_paddr;
+
+  memset ((void*)k_tls_addr, 0, pages * PAGE_SIZE);
+  memcpy ((void*)k_tls_addr, (void*)proc->procgroup->tls.tls_tmpl, tls_size);
+
+  uintptr_t ktcb = k_tls_addr + tls_size;
+  uintptr_t utcb = tls_vaddr + tls_size;
+
+  *(uintptr_t*)ktcb = utcb;
+
+  proc->pdata.fs_base = utcb;
+  proc->pdata.tls_vaddr = tls_vaddr;
+}

kernel/amd64/proc.h

@@ -4,14 +4,19 @@
 #include <amd64/intr.h>
 #include <libk/std.h>
 
+/* Top of userspace process' stack */
 #define PROC_USTACK_TOP 0x00007FFFFFFFF000ULL
+/* Size of userspace process' stack */
 #define USTACK_SIZE (256 * PAGE_SIZE)
+/* proc_map () base address */
+#define PROC_MAP_BASE 0x0000700000000000
 
+/* Platform-dependent process data */
 struct proc_platformdata {
   struct saved_regs regs;
-  uintptr_t syscall_stack;
+  uintptr_t kernel_stack;
-  uintptr_t user_stack;
+  uint64_t fs_base;
-  uint64_t fsbase;
+  uintptr_t tls_vaddr;
 };
 
 #endif // _KERNEL_AMD64_PROC_H

kernel/amd64/procgroup.h

@@ -0,0 +1,13 @@
+#ifndef _KERNEL_AMD64_PROCGRPUP_H
+#define _KERNEL_AMD64_PROCGRPUP_H
+
+#include <libk/std.h>
+
+struct procgroup_tls {
+  uint8_t* tls_tmpl;
+  size_t tls_tmpl_size;
+  size_t tls_tmpl_total_size;
+  size_t tls_tmpl_pages;
+};
+
+#endif // _KERNEL_AMD64_PROCGRPUP_H

kernel/amd64/regsasm.h

@@ -0,0 +1,55 @@
+#ifndef _KERNEL_AMD64_REGSASM_H
+#define _KERNEL_AMD64_REGSASM_H
+
+#define push_regs                                                                                  \
+  pushq % rax;                                                                                     \
+  pushq % rcx;                                                                                     \
+  pushq % rdx;                                                                                     \
+  pushq % rsi;                                                                                     \
+  pushq % rdi;                                                                                     \
+  pushq % rbp;                                                                                     \
+  pushq % rbx;                                                                                     \
+  pushq % r8;                                                                                      \
+  pushq % r9;                                                                                      \
+  pushq % r10;                                                                                     \
+  pushq % r11;                                                                                     \
+  pushq % r12;                                                                                     \
+  pushq % r13;                                                                                     \
+  pushq % r14;                                                                                     \
+  pushq % r15;
+
+#define pop_regs                                                                                   \
+  popq % r15;                                                                                      \
+  popq % r14;                                                                                      \
+  popq % r13;                                                                                      \
+  popq % r12;                                                                                      \
+  popq % r11;                                                                                      \
+  popq % r10;                                                                                      \
+  popq % r9;                                                                                       \
+  popq % r8;                                                                                       \
+  popq % rbx;                                                                                      \
+  popq % rbp;                                                                                      \
+  popq % rdi;                                                                                      \
+  popq % rsi;                                                                                      \
+  popq % rdx;                                                                                      \
+  popq % rcx;                                                                                      \
+  popq % rax;
+
+#define pop_regs_skip_rax                                                                          \
+  popq % r15;                                                                                      \
+  popq % r14;                                                                                      \
+  popq % r13;                                                                                      \
+  popq % r12;                                                                                      \
+  popq % r11;                                                                                      \
+  popq % r10;                                                                                      \
+  popq % r9;                                                                                       \
+  popq % r8;                                                                                       \
+  popq % rbx;                                                                                      \
+  popq % rbp;                                                                                      \
+  popq % rdi;                                                                                      \
+  popq % rsi;                                                                                      \
+  popq % rdx;                                                                                      \
+  popq % rcx;                                                                                      \
+  addq $8, % rsp
+
+#endif // _KERNEL_AMD64_REGSASM_H

kernel/amd64/sched.S

@@ -1,24 +1,9 @@
-#define pop_regs \
+#include <amd64/regsasm.h>
-  popq %r15; \
-  popq %r14; \
-  popq %r13; \
-  popq %r12; \
-  popq %r11; \
-  popq %r10; \
-  popq %r9; \
-  popq %r8; \
-  popq %rbx; \
-  popq %rbp; \
-  popq %rdi; \
-  popq %rsi; \
-  popq %rdx; \
-  popq %rcx; \
-  popq %rax;
 
 .global amd64_do_sched
 amd64_do_sched:
   movq %rsi, %cr3
   movq %rdi, %rsp
   pop_regs
-  add $16, %rsp
+  addq $16, %rsp
   iretq

kernel/amd64/sched.h

@@ -1,6 +1,7 @@
 #ifndef _KERNEL_AMD64_SCHED_H
 #define _KERNEL_AMD64_SCHED_H
 
+/// Perform process context switch
 void amd64_do_sched (void* regs, void* cr3);
 
 #endif // _KERNEL_AMD64_SCHED_H

kernel/amd64/sched1.c

@@ -1,4 +1,23 @@
+#include <amd64/msr-index.h>
+#include <amd64/msr.h>
 #include <amd64/sched.h>
+#include <libk/std.h>
+#include <proc/proc.h>
+#include <sync/spin_lock.h>
 #include <sys/mm.h>
+#include <sys/smp.h>
 
-void do_sched (void* regs, struct pd* pd) { amd64_do_sched (regs, (void*)pd->cr3_paddr); }
+void do_sched (struct proc* proc, spin_lock_t* cpu_lock, spin_lock_ctx_t* ctxcpu) {
+  spin_lock_ctx_t ctxpr;
+
+  spin_lock (&proc->lock, &ctxpr);
+
+  thiscpu->tss.rsp0 = proc->pdata.kernel_stack;
+  thiscpu->syscall_kernel_stack = proc->pdata.kernel_stack;
+  amd64_wrmsr (MSR_FS_BASE, proc->pdata.fs_base);
+
+  spin_unlock (&proc->lock, &ctxpr);
+  spin_unlock (cpu_lock, ctxcpu);
+
+  amd64_do_sched ((void*)&proc->pdata.regs, (void*)proc->procgroup->pd.cr3_paddr);
+}

kernel/amd64/smp.c

@@ -1,5 +1,6 @@
 #include <amd64/apic.h>
 #include <amd64/init.h>
+#include <amd64/intr_defs.h>
 #include <amd64/mm.h>
 #include <amd64/msr-index.h>
 #include <amd64/msr.h>
@@ -7,67 +8,107 @@
 #include <libk/string.h>
 #include <limine/requests.h>
 #include <mm/liballoc.h>
+#include <proc/proc.h>
 #include <sync/spin_lock.h>
 #include <sys/debug.h>
+#include <sys/sched.h>
 #include <sys/smp.h>
+#include <sys/syscall.h>
 
-static uint32_t cpu_counter = 0;
+/// Cpu ID counter
-static spin_lock_t cpu_counter_lock = SPIN_LOCK_INIT;
+static atomic_uint cpu_counter = 0;
+/// The CPUs
 static struct cpu cpus[CPUS_MAX];
 
-struct cpu* cpu_make (void) {
+static atomic_int cpu_init_count;
-  spin_lock (&cpu_counter_lock);
+
-  int id = cpu_counter++;
+/// Allocate a CPU structure
-  spin_unlock (&cpu_counter_lock);
+struct cpu* cpu_make (uint64_t lapic_id) {
+  int id = atomic_fetch_add (&cpu_counter, 1);
 
   struct cpu* cpu = &cpus[id];
 
   memset (cpu, 0, sizeof (*cpu));
   cpu->lock = SPIN_LOCK_INIT;
   cpu->id = id;
+  cpu->lapic_id = lapic_id;
 
-  return cpu_get (id);
+  amd64_wrmsr (MSR_GS_BASE, (uint64_t)cpu);
+
+  return cpu;
 }
 
-struct cpu* cpu_get (uint32_t id) {
+struct cpu* cpu_get (void) {
-  if (id >= CPUS_MAX)
+  struct cpu* ptr = (struct cpu*)amd64_rdmsr (MSR_GS_BASE);
-    return NULL;
+  return ptr;
-
-  return &cpus[id];
 }
 
-uint32_t cpu_id (void) { return (uint32_t)amd64_rdmsr (MSR_GS_BASE); }
+void cpu_request_sched (struct cpu* cpu) {
+  if (cpu == thiscpu) {
+    proc_sched ();
+    return;
+  }
 
-void cpu_assign (uint32_t id) { amd64_wrmsr (MSR_GS_BASE, (uint64_t)id); }
+  amd64_lapic_ipi (cpu->lapic_id, CPU_REQUEST_SCHED);
+}
 
+struct cpu* cpu_find_lightest (void) {
+  struct cpu* cpu = &cpus[0];
+
+  int load = atomic_load (&cpu->proc_run_q_count);
+
+  for (unsigned int i = 1; i < cpu_counter; i++) {
+    struct cpu* new_cpu = &cpus[i];
+    int new_load = atomic_load (&new_cpu->proc_run_q_count);
+    if (new_load < load) {
+      load = new_load;
+      cpu = new_cpu;
+    }
+  }
+
+  return cpu;
+}
+
+/// Bootstrap code for non-BSP CPUs
 static void amd64_smp_bootstrap (struct limine_mp_info* mp_info) {
   amd64_load_kernel_cr3 ();
 
-  struct cpu* cpu = cpu_make ();
+  struct cpu* cpu = cpu_make (mp_info->lapic_id);
-  cpu_assign (cpu->id);
 
   amd64_init (cpu, true); /* gdt + idt */
+  syscall_init ();
 
-  thiscpu->lapic_ticks = amd64_lapic_init (2500);
+  amd64_lapic_init (1000);
-  amd64_lapic_tick (thiscpu->lapic_ticks);
 
   DEBUG ("CPU %u is online!\n", thiscpu->id);
 
-  __asm__ volatile ("sti");
+  atomic_fetch_sub (&cpu_init_count, 1);
 
-  for (;;)
+  struct proc* spin_proc = proc_spawn_rd ("spin.exe");
-    ;
+  proc_register (spin_proc, thiscpu);
+
+  spin_lock_ctx_t ctxcpu;
+  spin_lock (&spin_proc->cpu->lock, &ctxcpu);
+  do_sched (spin_proc, &spin_proc->cpu->lock, &ctxcpu);
 }
 
+/// Initialize SMP subsystem for AMD64. Start AP CPUs
 void smp_init (void) {
-  thiscpu->lapic_ticks = amd64_lapic_init (2500);
+  amd64_lapic_init (1000);
 
   struct limine_mp_response* mp = limine_mp_request.response;
 
+  cpu_init_count = mp->cpu_count - 1; /* Don't include BSP */
+
   for (size_t i = 0; i < mp->cpu_count; i++) {
-    if (mp->cpus[i]->lapic_id != thiscpu->id) {
+    if (mp->cpus[i]->lapic_id != thiscpu->lapic_id) {
       DEBUG ("Trying CPU %u\n", mp->cpus[i]->lapic_id);
       mp->cpus[i]->goto_address = &amd64_smp_bootstrap;
     }
   }
+
+  while (atomic_load (&cpu_init_count) > 0)
+    ;
+
+  DEBUG ("All CPUs are online\n");
 }

kernel/amd64/smp.h

@@ -2,41 +2,43 @@
 #define _KERNEL_AMD64_SMP_H
 
 #include <amd64/gdt.h>
+#include <amd64/intr.h>
 #include <amd64/tss.h>
 #include <aux/compiler.h>
+#include <libk/rbtree.h>
 #include <libk/std.h>
 #include <proc/proc.h>
+#include <sync/spin_lock.h>
 
 #define CPUS_MAX 32
 
 struct cpu {
-  uint64_t lapic_ticks;
+  /* for syscall instruction */
-  uint32_t id;
+  uintptr_t syscall_user_stack;
-
+  uintptr_t syscall_kernel_stack;
-  struct {
-    uint64_t rflags;
-    atomic_int nesting;
-  } irq_ctx;
-
-  uint8_t user_stack[USTACK_SIZE] ALIGNED (16);
-
   volatile uint8_t kernel_stack[KSTACK_SIZE] ALIGNED (16);
   volatile uint8_t except_stack[KSTACK_SIZE] ALIGNED (16);
   volatile uint8_t irq_stack[KSTACK_SIZE] ALIGNED (16);
   volatile struct gdt_extended gdt ALIGNED (16);
   volatile struct tss tss;
 
+  uintptr_t lapic_mmio_base;
+  uint64_t lapic_ticks;
+  uint64_t lapic_id;
+  uint32_t id;
+
   spin_lock_t lock;
 
-  struct proc* proc_run_q;
+  struct list_node_link* proc_run_q;
   struct proc* proc_current;
+  atomic_int proc_run_q_count;
 };
 
-struct cpu* cpu_make (void);
+struct cpu* cpu_make (uint64_t lapic_id);
-struct cpu* cpu_get (uint32_t id);
+struct cpu* cpu_get (void);
-void cpu_assign (uint32_t id);
+void cpu_request_sched (struct cpu* cpu);
-uint32_t cpu_id (void);
+struct cpu* cpu_find_lightest (void);
 
-#define thiscpu (cpu_get (cpu_id ()))
+#define thiscpu (cpu_get ())
 
 #endif // _KERNEL_AMD64_SMP_H

kernel/amd64/spin.S

@@ -1,3 +1,4 @@
 .global amd64_spin
 amd64_spin:
+  hlt
   jmp amd64_spin

kernel/amd64/spin_lock.c

@@ -1,3 +1,4 @@
 #include <sys/spin_lock.h>
 
+/// Relax the spinlock using AMD64 pause instruction
 void spin_lock_relax (void) { __asm__ volatile ("pause"); }

kernel/amd64/src.mk

@@ -1,6 +1,5 @@
 c += amd64/bootmain.c \
 		 amd64/init.c \
-		 amd64/tss.c \
 		 amd64/io.c \
 		 amd64/debug.c \
 		 amd64/spin_lock.c \
@@ -11,15 +10,17 @@ c += amd64/bootmain.c \
 		 amd64/mm.c \
 		 amd64/time.c \
 		 amd64/smp.c \
-		 amd64/sched1.c
+		 amd64/sched1.c \
+		 amd64/proc.c \
+		 amd64/syscall.c
 
 S += amd64/intr_stub.S \
 		 amd64/spin.S \
-		 amd64/sched.S
+		 amd64/sched.S \
+		 amd64/syscallentry.S
 
 o += amd64/bootmain.o \
 		 amd64/init.o \
-		 amd64/tss.o \
 		 amd64/io.o \
 		 amd64/debug.o \
 		 amd64/spin_lock.o \
@@ -33,4 +34,7 @@ o += amd64/bootmain.o \
 		 amd64/time.o \
 		 amd64/smp.o \
 		 amd64/sched.o \
-		 amd64/sched1.o
+		 amd64/sched1.o \
+		 amd64/proc.o \
+		 amd64/syscall.o \
+		 amd64/syscallentry.o

kernel/amd64/syscall.c

@@ -0,0 +1,46 @@
+#include <amd64/gdt.h>
+#include <amd64/intr.h>
+#include <amd64/mm.h>
+#include <amd64/msr-index.h>
+#include <amd64/msr.h>
+#include <libk/string.h>
+#include <m/status.h>
+#include <m/syscall_defs.h>
+#include <proc/proc.h>
+#include <sys/debug.h>
+#include <sys/smp.h>
+#include <syscall/syscall.h>
+
+extern void amd64_syscall_entry (void);
+
+uintptr_t amd64_syscall_dispatch (void* stack_ptr) {
+  spin_lock_ctx_t ctxcpu, ctxpr;
+
+  amd64_load_kernel_cr3 ();
+  struct saved_regs* regs = stack_ptr;
+
+  spin_lock (&thiscpu->lock, &ctxcpu);
+  struct proc* caller = thiscpu->proc_current;
+  spin_lock (&caller->lock, &ctxpr);
+
+  memcpy (&caller->pdata.regs, regs, sizeof (struct saved_regs));
+
+  spin_unlock (&caller->lock, &ctxpr);
+  spin_unlock (&thiscpu->lock, &ctxcpu);
+
+  int syscall_num = regs->rax;
+  syscall_handler_func_t func = syscall_find_handler (syscall_num);
+
+  if (func == NULL) {
+    return -ST_SYSCALL_NOT_FOUND;
+  }
+
+  return func (caller, regs, regs->rdi, regs->rsi, regs->rdx, regs->r10, regs->r8, regs->r9);
+}
+
+void syscall_init (void) {
+  amd64_wrmsr (MSR_STAR, ((uint64_t)GDT_KCODE << 32) | ((uint64_t)(GDT_KDATA | 0x03) << 48));
+  amd64_wrmsr (MSR_LSTAR, (uint64_t)&amd64_syscall_entry);
+  amd64_wrmsr (MSR_SYSCALL_MASK, (1ULL << 9));
+  amd64_wrmsr (MSR_EFER, amd64_rdmsr (MSR_EFER) | EFER_SCE);
+}

kernel/amd64/syscallentry.S

@@ -0,0 +1,49 @@
+#include <amd64/regsasm.h>
+
+.extern amd64_syscall_dispatch
+
+.global amd64_syscall_entry
+amd64_syscall_entry:
+  cli
+
+  movq %rsp, %gs:0
+  movq %gs:8, %rsp
+ 
+  pushq $0x1b
+  pushq %gs:0
+  pushq %r11
+  pushq $0x23
+  pushq %rcx
+  pushq $0
+  pushq $0
+
+  push_regs
+
+  movw $0x10, %ax
+  movw %ax, %ds
+  movw %ax, %es
+  movw %ax, %ss
+
+  cld
+
+  movq %rsp, %rdi
+
+  movq %cr3, %rax; pushq %rax
+
+  movq %rsp, %rbp
+
+  subq $8, %rsp
+  andq $-16, %rsp
+
+  callq amd64_syscall_dispatch
+
+  movq %rbp, %rsp
+
+  popq %rbx; movq %rbx, %cr3
+
+  pop_regs_skip_rax
+  
+  addq $56, %rsp
+  movq %gs:0, %rsp
+  
+  sysretq

kernel/amd64/time.c

@@ -2,4 +2,5 @@
 #include <libk/std.h>
 #include <sys/time.h>
 
+/// Sleep for given amount of microseconds
 void sleep_micro (size_t us) { amd64_hpet_sleep_micro (us); }

kernel/amd64/tss.c

@@ -1,7 +0,0 @@
-#include <amd64/tss.h>
-#include <aux/compiler.h>
-#include <libk/std.h>
-
-ALIGNED (16) static volatile struct tss tss;
-
-volatile struct tss* amd64_get_tss (void) { return &tss; }

kernel/amd64/tss.h

@@ -4,6 +4,7 @@
 #include <aux/compiler.h>
 #include <libk/std.h>
 
+/// 64-bit TSS structure: https://wiki.osdev.org/Task_State_Segment
 struct tss {
   uint32_t resv0;
   uint64_t rsp0;
@@ -16,6 +17,4 @@ struct tss {
   uint16_t iopb_off;
 } PACKED;
 
-volatile struct tss* amd64_get_tss (void);
-
 #endif // _KERNEL_AMD64_TSS_H

kernel/aux/compiler.h

@@ -4,5 +4,6 @@
 #define PACKED        __attribute__ ((packed))
 #define ALIGNED(N)    __attribute__ ((aligned ((N))))
 #define SECTION(name) __attribute__ ((section (name)))
+#define UNUSED        __attribute__ ((unused))
 
 #endif // _KERNEL_AUX_COMPILER_H

kernel/aux/elf.h

@@ -391,10 +391,10 @@ typedef struct {
 #define SHN_LORESERVE 0xff00 /* Start of reserved indices */
 #define SHN_LOPROC    0xff00 /* Start of processor-specific */
 #define SHN_BEFORE                                                                                 \
-  0xff00 /* Order section before all others
+  0xff00 /* Order section before all others                                                        \
              (Solaris).  */
 #define SHN_AFTER                                                                                  \
-  0xff01                     /* Order section after all others
+  0xff01                     /* Order section after all others                                     \
              (Solaris).  */
 #define SHN_HIPROC    0xff1f /* End of processor-specific */
 #define SHN_LOOS      0xff20 /* Start of OS-specific */
@@ -454,7 +454,7 @@ typedef struct {
 #define SHF_INFO_LINK  (1 << 6) /* `sh_info' contains SHT index */
 #define SHF_LINK_ORDER (1 << 7) /* Preserve order after combining */
 #define SHF_OS_NONCONFORMING                                                                       \
-  (1 << 8)                        /* Non-standard OS specific handling
+  (1 << 8)                        /* Non-standard OS specific handling                             \
              required */
 #define SHF_GROUP      (1 << 9)   /* Section is member of a group.  */
 #define SHF_TLS        (1 << 10)  /* Section hold thread-local data.  */
@@ -463,10 +463,10 @@ typedef struct {
 #define SHF_MASKPROC   0xf0000000 /* Processor-specific */
 #define SHF_GNU_RETAIN (1 << 21)  /* Not to be GCed by linker.  */
 #define SHF_ORDERED                                                                                \
-  (1 << 30) /* Special ordering requirement
+  (1 << 30) /* Special ordering requirement                                                        \
              (Solaris).  */
 #define SHF_EXCLUDE                                                                                \
-  (1U << 31) /* Section is excluded unless
+  (1U << 31) /* Section is excluded unless                                                         \
              referenced or allocated (Solaris).*/
 
 /* Section compression header.  Used when SHF_COMPRESSED is set.  */
@@ -538,7 +538,7 @@ typedef struct {
 #define SYMINFO_FLG_PASSTHRU 0x0002 /* Pass-through symbol for translator */
 #define SYMINFO_FLG_COPY     0x0004 /* Symbol is a copy-reloc */
 #define SYMINFO_FLG_LAZYLOAD                                                                       \
-  0x0008 /* Symbol bound to object to be lazy
+  0x0008 /* Symbol bound to object to be lazy                                                      \
              loaded */
 /* Syminfo version values.  */
 #define SYMINFO_NONE    0
@@ -716,7 +716,7 @@ typedef struct {
 
 #define NT_PRSTATUS 1 /* Contains copy of prstatus struct */
 #define NT_PRFPREG                                                                                 \
-  2                      /* Contains copy of fpregset
+  2                      /* Contains copy of fpregset                                              \
              struct.  */
 #define NT_FPREGSET   2  /* Contains copy of fpregset struct */
 #define NT_PRPSINFO   3  /* Contains copy of prpsinfo struct */
@@ -734,10 +734,10 @@ typedef struct {
 #define NT_LWPSINFO   17 /* Contains copy of lwpinfo struct */
 #define NT_PRFPXREG   20 /* Contains copy of fprxregset struct */
 #define NT_SIGINFO                                                                                 \
-  0x53494749 /* Contains copy of siginfo_t,
+  0x53494749 /* Contains copy of siginfo_t,                                                        \
              size might increase */
 #define NT_FILE                                                                                    \
-  0x46494c45                      /* Contains information about mapped
+  0x46494c45                      /* Contains information about mapped                             \
              files */
 #define NT_PRXFPREG    0x46e62b7f /* Contains copy of user_fxsr_struct */
 #define NT_PPC_VMX     0x100      /* PowerPC Altivec/VMX registers */
@@ -754,16 +754,16 @@ typedef struct {
 #define NT_PPC_TM_CVSX 0x10b      /* TM checkpointed VSX Registers */
 #define NT_PPC_TM_SPR  0x10c      /* TM Special Purpose Registers */
 #define NT_PPC_TM_CTAR                                                                             \
-  0x10d /* TM checkpointed Target Address
+  0x10d /* TM checkpointed Target Address                                                          \
              Register */
 #define NT_PPC_TM_CPPR                                                                             \
-  0x10e /* TM checkpointed Program Priority
+  0x10e /* TM checkpointed Program Priority                                                        \
              Register */
 #define NT_PPC_TM_CDSCR                                                                            \
-  0x10f /* TM checkpointed Data Stream Control
+  0x10f /* TM checkpointed Data Stream Control                                                     \
              Register */
 #define NT_PPC_PKEY                                                                                \
-  0x110                           /* Memory Protection Keys
+  0x110                           /* Memory Protection Keys                                        \
              registers.  */
 #define NT_PPC_DEXCR        0x111 /* PowerPC DEXCR registers.  */
 #define NT_PPC_HASHKEYR     0x112 /* PowerPC HASHKEYR register.  */
@@ -782,12 +782,12 @@ typedef struct {
 #define NT_S390_SYSTEM_CALL 0x307 /* s390 system call restart data */
 #define NT_S390_TDB         0x308 /* s390 transaction diagnostic block */
 #define NT_S390_VXRS_LOW                                                                           \
-  0x309                         /* s390 vector registers 0-15
+  0x309                         /* s390 vector registers 0-15                                      \
              upper half.  */
 #define NT_S390_VXRS_HIGH 0x30a /* s390 vector registers 16-31.  */
 #define NT_S390_GS_CB     0x30b /* s390 guarded storage registers.  */
 #define NT_S390_GS_BC                                                                              \
-  0x30c                           /* s390 guarded storage
+  0x30c                           /* s390 guarded storage                                          \
              broadcast control block.  */
 #define NT_S390_RI_CB       0x30d /* s390 runtime instrumentation.  */
 #define NT_S390_PV_CPU_DATA 0x30e /* s390 protvirt cpu dump data.  */
@@ -797,22 +797,22 @@ typedef struct {
 #define NT_ARM_HW_WATCH     0x403 /* ARM hardware watchpoint registers */
 #define NT_ARM_SYSTEM_CALL  0x404 /* ARM system call number */
 #define NT_ARM_SVE                                                                                 \
-  0x405 /* ARM Scalable Vector Extension
+  0x405 /* ARM Scalable Vector Extension                                                           \
              registers */
 #define NT_ARM_PAC_MASK                                                                            \
-  0x406 /* ARM pointer authentication
+  0x406 /* ARM pointer authentication                                                              \
              code masks.  */
 #define NT_ARM_PACA_KEYS                                                                           \
-  0x407 /* ARM pointer authentication
+  0x407 /* ARM pointer authentication                                                              \
              address keys.  */
 #define NT_ARM_PACG_KEYS                                                                           \
-  0x408 /* ARM pointer authentication
+  0x408 /* ARM pointer authentication                                                              \
              generic key.  */
 #define NT_ARM_TAGGED_ADDR_CTRL                                                                    \
-  0x409 /* AArch64 tagged address
+  0x409 /* AArch64 tagged address                                                                  \
              control.  */
 #define NT_ARM_PAC_ENABLED_KEYS                                                                    \
-  0x40a                       /* AArch64 pointer authentication
+  0x40a                       /* AArch64 pointer authentication                                    \
              enabled keys.  */
 #define NT_ARM_SSVE     0x40b /* ARM Streaming SVE registers.  */
 #define NT_ARM_ZA       0x40c /* ARM SME ZA registers.  */
@@ -827,20 +827,20 @@ typedef struct {
 #define NT_RISCV_CSR    0x900 /* RISC-V Control and Status Registers */
 #define NT_RISCV_VECTOR 0x901 /* RISC-V vector registers */
 #define NT_RISCV_TAGGED_ADDR_CTRL                                                                  \
-  0x902                           /* RISC-V tagged
+  0x902                           /* RISC-V tagged                                                 \
                address control */
 #define NT_LOONGARCH_CPUCFG 0xa00 /* LoongArch CPU config registers.  */
 #define NT_LOONGARCH_CSR                                                                           \
-  0xa01 /* LoongArch control and
+  0xa01 /* LoongArch control and                                                                   \
              status registers.  */
 #define NT_LOONGARCH_LSX                                                                           \
-  0xa02 /* LoongArch Loongson SIMD
+  0xa02 /* LoongArch Loongson SIMD                                                                 \
              Extension registers.  */
 #define NT_LOONGARCH_LASX                                                                          \
-  0xa03 /* LoongArch Loongson Advanced
+  0xa03 /* LoongArch Loongson Advanced                                                             \
              SIMD Extension registers.  */
 #define NT_LOONGARCH_LBT                                                                           \
-  0xa04                             /* LoongArch Loongson Binary
+  0xa04                             /* LoongArch Loongson Binary                                   \
              Translation registers.  */
 #define NT_LOONGARCH_HW_BREAK 0xa05 /* LoongArch hardware breakpoint registers */
 #define NT_LOONGARCH_HW_WATCH 0xa06 /* LoongArch hardware watchpoint registers */
@@ -927,7 +927,7 @@ typedef struct {
 #define DT_MOVESZ         0x6ffffdfb
 #define DT_FEATURE_1      0x6ffffdfc /* Feature selection (DTF_*).  */
 #define DT_POSFLAG_1                                                                               \
-  0x6ffffdfd                         /* Flags for DT_* entries, effecting
+  0x6ffffdfd                         /* Flags for DT_* entries, effecting                          \
              the following DT_* entry.  */
 #define DT_SYMINSZ        0x6ffffdfe /* Size of syminfo table (in bytes) */
 #define DT_SYMINENT       0x6ffffdff /* Entry size of syminfo */
@@ -966,11 +966,11 @@ typedef struct {
 /* These were chosen by Sun.  */
 #define DT_FLAGS_1 0x6ffffffb /* State flags, see DF_1_* below.  */
 #define DT_VERDEF                                                                                  \
-  0x6ffffffc                    /* Address of version definition
+  0x6ffffffc                    /* Address of version definition                                   \
              table */
 #define DT_VERDEFNUM 0x6ffffffd /* Number of version definitions */
 #define DT_VERNEED                                                                                 \
-  0x6ffffffe                                          /* Address of table with needed
+  0x6ffffffe                                          /* Address of table with needed              \
              versions */
 #define DT_VERNEEDNUM         0x6fffffff              /* Number of needed versions */
 #define DT_VERSIONTAGIDX(tag) (DT_VERNEEDNUM - (tag)) /* Reverse order! */
@@ -1031,7 +1031,7 @@ typedef struct {
 /* Flags in the DT_POSFLAG_1 entry effecting only the next DT_* entry.  */
 #define DF_P1_LAZYLOAD 0x00000001 /* Lazyload following object.  */
 #define DF_P1_GROUPPERM                                                                            \
-  0x00000002 /* Symbols from next object are not
+  0x00000002 /* Symbols from next object are not                                                   \
              generally available.  */
 
 /* Version definition sections.  */
@@ -1066,7 +1066,7 @@ typedef struct {
 /* Legal values for vd_flags (version information flags).  */
 #define VER_FLG_BASE 0x1 /* Version definition of file itself */
 #define VER_FLG_WEAK                                                                               \
-  0x2 /* Weak version identifier.  Also
+  0x2 /* Weak version identifier.  Also                                                            \
              used by vna_flags below.  */
 
 /* Versym symbol index values.  */
@@ -1187,7 +1187,7 @@ typedef struct {
 /* Some more special a_type values describing the hardware.  */
 #define AT_PLATFORM 15 /* String identifying platform.  */
 #define AT_HWCAP                                                                                   \
-  16 /* Machine-dependent hints about
+  16 /* Machine-dependent hints about                                                              \
              processor capabilities.  */
 
 /* This entry gives some information about the FPU initialization
@@ -1210,7 +1210,7 @@ typedef struct {
 #define AT_RANDOM 25 /* Address of 16 random bytes.  */
 
 #define AT_HWCAP2                                                                                  \
-  26 /* More machine-dependent hints about
+  26 /* More machine-dependent hints about                                                         \
              processor capabilities.  */
 
 #define AT_RSEQ_FEATURE_SIZE 27 /* rseq supported feature size.  */
@@ -1465,13 +1465,13 @@ typedef struct {
 #define R_68K_TLS_IE16  35 /* 16 bit GOT offset for IE */
 #define R_68K_TLS_IE8   36 /* 8 bit GOT offset for IE */
 #define R_68K_TLS_LE32                                                                             \
-  37 /* 32 bit offset relative to
+  37 /* 32 bit offset relative to                                                                  \
              static TLS block */
 #define R_68K_TLS_LE16                                                                             \
-  38 /* 16 bit offset relative to
+  38 /* 16 bit offset relative to                                                                  \
              static TLS block */
 #define R_68K_TLS_LE8                                                                              \
-  39                          /* 8 bit offset relative to
+  39                          /* 8 bit offset relative to                                          \
              static TLS block */
 #define R_68K_TLS_DTPMOD32 40 /* 32 bit module number */
 #define R_68K_TLS_DTPREL32 41 /* 32 bit module-relative offset */
@@ -1497,47 +1497,47 @@ typedef struct {
 #define R_386_32PLT     11
 #define R_386_TLS_TPOFF 14 /* Offset in static TLS block */
 #define R_386_TLS_IE                                                                               \
-  15 /* Address of GOT entry for static TLS
+  15 /* Address of GOT entry for static TLS                                                        \
              block offset */
 #define R_386_TLS_GOTIE                                                                            \
-  16 /* GOT entry for static TLS block
+  16 /* GOT entry for static TLS block                                                             \
              offset */
 #define R_386_TLS_LE                                                                               \
-  17 /* Offset relative to static TLS
+  17 /* Offset relative to static TLS                                                              \
              block */
 #define R_386_TLS_GD                                                                               \
-  18 /* Direct 32 bit for GNU version of
+  18 /* Direct 32 bit for GNU version of                                                           \
              general dynamic thread local data */
 #define R_386_TLS_LDM                                                                              \
-  19 /* Direct 32 bit for GNU version of
+  19 /* Direct 32 bit for GNU version of                                                           \
-					   local dynamic thread local data
+             local dynamic thread local data                                                       \
              in LE code */
 #define R_386_16   20
 #define R_386_PC16 21
 #define R_386_8    22
 #define R_386_PC8  23
 #define R_386_TLS_GD_32                                                                            \
-  24                         /* Direct 32 bit for general dynamic
+  24                         /* Direct 32 bit for general dynamic                                  \
              thread local data */
 #define R_386_TLS_GD_PUSH 25 /* Tag for pushl in GD TLS code */
 #define R_386_TLS_GD_CALL                                                                          \
-  26                        /* Relocation for call to
+  26                        /* Relocation for call to                                              \
              __tls_get_addr() */
 #define R_386_TLS_GD_POP 27 /* Tag for popl in GD TLS code */
 #define R_386_TLS_LDM_32                                                                           \
-  28                          /* Direct 32 bit for local dynamic
+  28                          /* Direct 32 bit for local dynamic                                   \
              thread local data in LE code */
 #define R_386_TLS_LDM_PUSH 29 /* Tag for pushl in LDM TLS code */
 #define R_386_TLS_LDM_CALL                                                                         \
-  30                         /* Relocation for call to
+  30                         /* Relocation for call to                                             \
              __tls_get_addr() in LDM code */
 #define R_386_TLS_LDM_POP 31 /* Tag for popl in LDM TLS code */
 #define R_386_TLS_LDO_32  32 /* Offset relative to TLS block */
 #define R_386_TLS_IE_32                                                                            \
-  33 /* GOT entry for negated static TLS
+  33 /* GOT entry for negated static TLS                                                           \
              block offset */
 #define R_386_TLS_LE_32                                                                            \
-  34                          /* Negated offset relative to static
+  34                          /* Negated offset relative to static                                 \
              TLS block */
 #define R_386_TLS_DTPMOD32 35 /* ID of module containing symbol */
 #define R_386_TLS_DTPOFF32 36 /* Offset in TLS block */
@@ -1545,17 +1545,17 @@ typedef struct {
 #define R_386_SIZE32       38 /* 32-bit symbol size */
 #define R_386_TLS_GOTDESC  39 /* GOT offset for TLS descriptor.  */
 #define R_386_TLS_DESC_CALL                                                                        \
-  40 /* Marker of call through TLS
+  40 /* Marker of call through TLS                                                                 \
-					   descriptor for
+             descriptor for                                                                        \
              relaxation.  */
 #define R_386_TLS_DESC                                                                             \
-  41                       /* TLS descriptor containing
+  41                       /* TLS descriptor containing                                            \
-					   pointer to code and to
+             pointer to code and to                                                       \
-					   argument, returning the TLS
+             argument, returning the TLS                                                  \
              offset for the symbol.  */
 #define R_386_IRELATIVE 42 /* Adjust indirectly by program base */
 #define R_386_GOT32X                                                                               \
-  43 /* Load from 32 bit GOT entry,
+  43 /* Load from 32 bit GOT entry,                                                                \
              relaxable. */
 /* Keep this the last entry.  */
 #define R_386_NUM 44
@@ -1698,26 +1698,26 @@ typedef struct {
 #define EF_MIPS_ABI2      32
 #define EF_MIPS_ABI_ON32  64
 #define EF_MIPS_OPTIONS_FIRST                                                                      \
-  0x00000080 /* Process the .MIPS.options
+  0x00000080 /* Process the .MIPS.options                                                          \
                 section first by ld.  */
 #define EF_MIPS_32BITMODE                                                                          \
-  0x00000100                 /* Indicates code compiled for
+  0x00000100                 /* Indicates code compiled for                                        \
-					      a 64-bit machine in 32-bit
+                a 64-bit machine in 32-bit                                                         \
-					      mode (regs are 32-bits
+                mode (regs are 32-bits                                                             \
                 wide).  */
 #define EF_MIPS_FP64    512  /* Uses FP64 (12 callee-saved).  */
 #define EF_MIPS_NAN2008 1024 /* Uses IEEE 754-2008 NaN encoding.  */
 #define EF_MIPS_ARCH_ASE                                                                           \
-  0x0f000000 /* Architectural Extensions
+  0x0f000000 /* Architectural Extensions                                                           \
                 used by this file.  */
 #define EF_MIPS_ARCH_ASE_MDMX                                                                      \
-  0x08000000 /* Use MDMX multimedia
+  0x08000000 /* Use MDMX multimedia                                                                \
                 extensions.  */
 #define EF_MIPS_ARCH_ASE_M16                                                                       \
-  0x04000000 /* Use MIPS-16 ISA
+  0x04000000 /* Use MIPS-16 ISA                                                                    \
                 extensions.  */
 #define EF_MIPS_ARCH_ASE_MICROMIPS                                                                 \
-  0x02000000                    /* Use MICROMIPS ISA
+  0x02000000                    /* Use MICROMIPS ISA                                               \
                   extensions.  */
 #define EF_MIPS_ARCH 0xf0000000 /* MIPS architecture level.  */
 
@@ -1735,11 +1735,11 @@ typedef struct {
 #define EF_MIPS_ARCH_32R6 0x90000000 /* MIPS32r6 code.  */
 #define EF_MIPS_ARCH_64R6 0xa0000000 /* MIPS64r6 code.  */
 #define EF_MIPS_ABI                                                                                \
-  0x0000F000                       /* The ABI of the file.  Also
+  0x0000F000                       /* The ABI of the file.  Also                                   \
                 see EF_MIPS_ABI2 above.  */
 #define EF_MIPS_ABI_O32 0x00001000 /* The original o32 abi.  */
 #define EF_MIPS_ABI_O64                                                                            \
-  0x00002000                             /* O32 extended to work on
+  0x00002000                             /* O32 extended to work on                                \
                 64 bit architectures.  */
 #define EF_MIPS_ABI_EABI32    0x00003000 /* EABI in 32 bit mode.  */
 #define EF_MIPS_ABI_EABI64    0x00004000 /* EABI in 64 bit mode.  */
@@ -2083,27 +2083,27 @@ typedef struct {
 #define DT_MIPS_RLD_MAP      0x70000016 /* Address of run time loader map.  */
 #define DT_MIPS_DELTA_CLASS  0x70000017 /* Delta C++ class definition.  */
 #define DT_MIPS_DELTA_CLASS_NO                                                                     \
-  0x70000018                              /* Number of entries in
+  0x70000018                              /* Number of entries in                                  \
             DT_MIPS_DELTA_CLASS.  */
 #define DT_MIPS_DELTA_INSTANCE 0x70000019 /* Delta C++ class instances.  */
 #define DT_MIPS_DELTA_INSTANCE_NO                                                                  \
-  0x7000001a                           /* Number of entries in
+  0x7000001a                           /* Number of entries in                                     \
             DT_MIPS_DELTA_INSTANCE.  */
 #define DT_MIPS_DELTA_RELOC 0x7000001b /* Delta relocations.  */
 #define DT_MIPS_DELTA_RELOC_NO                                                                     \
-  0x7000001c /* Number of entries in
+  0x7000001c /* Number of entries in                                                               \
                DT_MIPS_DELTA_RELOC.  */
 #define DT_MIPS_DELTA_SYM                                                                          \
-  0x7000001d /* Delta symbols that Delta
+  0x7000001d /* Delta symbols that Delta                                                           \
              relocations refer to.  */
 #define DT_MIPS_DELTA_SYM_NO                                                                       \
-  0x7000001e /* Number of entries in
+  0x7000001e /* Number of entries in                                                               \
              DT_MIPS_DELTA_SYM.  */
 #define DT_MIPS_DELTA_CLASSSYM                                                                     \
-  0x70000020 /* Delta symbols that hold the
+  0x70000020 /* Delta symbols that hold the                                                        \
                class declaration.  */
 #define DT_MIPS_DELTA_CLASSSYM_NO                                                                  \
-  0x70000021                                /* Number of entries in
+  0x70000021                                /* Number of entries in                                \
             DT_MIPS_DELTA_CLASSSYM.  */
 #define DT_MIPS_CXX_FLAGS        0x70000022 /* Flags indicating for C++ flavor.  */
 #define DT_MIPS_PIXIE_INIT       0x70000023
@@ -2117,10 +2117,10 @@ typedef struct {
 #define DT_MIPS_DYNSTR_ALIGN     0x7000002b
 #define DT_MIPS_INTERFACE_SIZE   0x7000002c /* Size of the .interface section. */
 #define DT_MIPS_RLD_TEXT_RESOLVE_ADDR                                                              \
-  0x7000002d /* Address of rld_text_rsolve
+  0x7000002d /* Address of rld_text_rsolve                                                         \
                 function stored in GOT.  */
 #define DT_MIPS_PERF_SUFFIX                                                                        \
-  0x7000002e                            /* Default suffix of dso to be added
+  0x7000002e                            /* Default suffix of dso to be added                       \
              by rld on dlopen() calls.  */
 #define DT_MIPS_COMPACT_SIZE 0x7000002f /* (O32)Size of compact rel section. */
 #define DT_MIPS_GP_VALUE     0x70000030 /* GP value for aux GOTs.  */
@@ -2293,7 +2293,7 @@ enum {
 #define EF_PARISC_LSB     0x00040000 /* Program expects little endian. */
 #define EF_PARISC_WIDE    0x00080000 /* Program expects wide mode.  */
 #define EF_PARISC_NO_KABP                                                                          \
-  0x00100000                          /* No kernel assisted branch
+  0x00100000                          /* No kernel assisted branch                                 \
                 prediction.  */
 #define EF_PARISC_LAZYSWAP 0x00400000 /* Allow lazy swapping.  */
 #define EF_PARISC_ARCH     0x0000ffff /* Architecture version.  */
@@ -2307,7 +2307,7 @@ enum {
 /* Additional section indices.  */
 
 #define SHN_PARISC_ANSI_COMMON                                                                     \
-  0xff00                              /* Section for tentatively declared
+  0xff00                              /* Section for tentatively declared                          \
                 symbols in ANSI C.  */
 #define SHN_PARISC_HUGE_COMMON 0xff01 /* Common blocks in huge model.  */
 
@@ -2555,7 +2555,7 @@ enum {
 /* Cygnus local bits below */
 #define EF_PPC_RELOCATABLE 0x00010000 /* PowerPC -mrelocatable flag*/
 #define EF_PPC_RELOCATABLE_LIB                                                                     \
-  0x00008000 /* PowerPC -mrelocatable-lib
+  0x00008000 /* PowerPC -mrelocatable-lib                                                          \
                flag */
 
 /* PowerPC relocations defined by the ABIs */
@@ -2877,12 +2877,12 @@ enum {
 /* ARM-specific values for sh_flags */
 #define SHF_ARM_ENTRYSECT 0x10000000 /* Section contains an entry point */
 #define SHF_ARM_COMDEF                                                                             \
-  0x80000000 /* Section may be multiply defined
+  0x80000000 /* Section may be multiply defined                                                    \
                 in the input to a link step.  */
 
 /* ARM-specific program header flags */
 #define PF_ARM_SB                                                                                  \
-  0x10000000                  /* Segment contains the location
+  0x10000000                  /* Segment contains the location                                     \
                 addressed by the static base. */
 #define PF_ARM_PI  0x20000000 /* Position-independent segment.  */
 #define PF_ARM_ABS 0x40000000 /* Absolute segment.  */
@@ -3038,7 +3038,7 @@ enum {
 
 #define R_ARM_NONE 0 /* No reloc */
 #define R_ARM_PC24                                                                                 \
-  1                      /* Deprecated PC relative 26
+  1                      /* Deprecated PC relative 26                                              \
              bit branch.  */
 #define R_ARM_ABS32    2 /* Direct 32 bit  */
 #define R_ARM_REL32    3 /* PC relative 32 bit */
@@ -3050,7 +3050,7 @@ enum {
 #define R_ARM_SBREL32  9
 #define R_ARM_THM_PC22 10 /* PC relative 24 bit (Thumb32 BL).  */
 #define R_ARM_THM_PC8                                                                              \
-  11 /* PC relative & 0x3FC
+  11 /* PC relative & 0x3FC                                                                        \
              (Thumb16 LDR, ADD, ADR).  */
 #define R_ARM_AMP_VCALL9   12
 #define R_ARM_SWI24        13 /* Obsolete static relocation.  */
@@ -3071,7 +3071,7 @@ enum {
 #define R_ARM_PLT32        27 /* Deprecated, 32 bit PLT address.  */
 #define R_ARM_CALL         28 /* PC relative 24 bit (BL, BLX).  */
 #define R_ARM_JUMP24                                                                               \
-  29                             /* PC relative 24 bit
+  29                             /* PC relative 24 bit                                             \
              (B, BL<cond>).  */
 #define R_ARM_THM_JUMP24      30 /* PC relative 24 bit (Thumb32 B.W).  */
 #define R_ARM_BASE_ABS        31 /* Adjust by program base.  */
@@ -3092,25 +3092,25 @@ enum {
 #define R_ARM_MOVT_PREL       46 /* PC relative (MOVT).  */
 #define R_ARM_THM_MOVW_ABS_NC 47 /* Direct 16 bit (Thumb32 MOVW).  */
 #define R_ARM_THM_MOVT_ABS                                                                         \
-  48 /* Direct high 16 bit
+  48 /* Direct high 16 bit                                                                         \
              (Thumb32 MOVT).  */
 #define R_ARM_THM_MOVW_PREL_NC                                                                     \
-  49 /* PC relative 16 bit
+  49 /* PC relative 16 bit                                                                         \
              (Thumb32 MOVW).  */
 #define R_ARM_THM_MOVT_PREL                                                                        \
-  50 /* PC relative high 16 bit
+  50 /* PC relative high 16 bit                                                                    \
              (Thumb32 MOVT).  */
 #define R_ARM_THM_JUMP19                                                                           \
-  51 /* PC relative 20 bit
+  51 /* PC relative 20 bit                                                                         \
              (Thumb32 B<cond>.W).  */
 #define R_ARM_THM_JUMP6                                                                            \
-  52 /* PC relative X & 0x7E
+  52 /* PC relative X & 0x7E                                                                       \
              (Thumb16 CBZ, CBNZ).  */
 #define R_ARM_THM_ALU_PREL_11_0                                                                    \
-  53 /* PC relative 12 bit
+  53 /* PC relative 12 bit                                                                         \
              (Thumb32 ADR.W).  */
 #define R_ARM_THM_PC12                                                                             \
-  54                          /* PC relative 12 bit
+  54                          /* PC relative 12 bit                                                \
              (Thumb32 LDR{D,SB,H,SH}).  */
 #define R_ARM_ABS32_NOI    55 /* Direct 32-bit.  */
 #define R_ARM_REL32_NOI    56 /* PC relative 32-bit.  */
@@ -3122,13 +3122,13 @@ enum {
 #define R_ARM_LDR_PC_G1    62 /* PC relative (LDR,STR,LDRB,STRB).  */
 #define R_ARM_LDR_PC_G2    63 /* PC relative (LDR,STR,LDRB,STRB).  */
 #define R_ARM_LDRS_PC_G0                                                                           \
-  64 /* PC relative (STR{D,H},
+  64 /* PC relative (STR{D,H},                                                                     \
              LDR{D,SB,H,SH}).  */
 #define R_ARM_LDRS_PC_G1                                                                           \
-  65 /* PC relative (STR{D,H},
+  65 /* PC relative (STR{D,H},                                                                     \
              LDR{D,SB,H,SH}).  */
 #define R_ARM_LDRS_PC_G2                                                                           \
-  66                          /* PC relative (STR{D,H},
+  66                          /* PC relative (STR{D,H},                                            \
              LDR{D,SB,H,SH}).  */
 #define R_ARM_LDC_PC_G0    67 /* PC relative (LDC, STC).  */
 #define R_ARM_LDC_PC_G1    68 /* PC relative (LDC, STC).  */
@@ -3139,43 +3139,43 @@ enum {
 #define R_ARM_ALU_SB_G1    73 /* Program base relative (ADD,SUB).  */
 #define R_ARM_ALU_SB_G2    74 /* Program base relative (ADD,SUB).  */
 #define R_ARM_LDR_SB_G0                                                                            \
-  75 /* Program base relative (LDR,
+  75 /* Program base relative (LDR,                                                                \
              STR, LDRB, STRB).  */
 #define R_ARM_LDR_SB_G1                                                                            \
-  76 /* Program base relative
+  76 /* Program base relative                                                                      \
              (LDR, STR, LDRB, STRB).  */
 #define R_ARM_LDR_SB_G2                                                                            \
-  77 /* Program base relative
+  77 /* Program base relative                                                                      \
              (LDR, STR, LDRB, STRB).  */
 #define R_ARM_LDRS_SB_G0                                                                           \
-  78 /* Program base relative
+  78 /* Program base relative                                                                      \
              (LDR, STR, LDRB, STRB).  */
 #define R_ARM_LDRS_SB_G1                                                                           \
-  79 /* Program base relative
+  79 /* Program base relative                                                                      \
              (LDR, STR, LDRB, STRB).  */
 #define R_ARM_LDRS_SB_G2                                                                           \
-  80                       /* Program base relative
+  80                       /* Program base relative                                                \
              (LDR, STR, LDRB, STRB).  */
 #define R_ARM_LDC_SB_G0 81 /* Program base relative (LDC,STC).  */
 #define R_ARM_LDC_SB_G1 82 /* Program base relative (LDC,STC).  */
 #define R_ARM_LDC_SB_G2 83 /* Program base relative (LDC,STC).  */
 #define R_ARM_MOVW_BREL_NC                                                                         \
-  84 /* Program base relative 16
+  84 /* Program base relative 16                                                                   \
              bit (MOVW).  */
 #define R_ARM_MOVT_BREL                                                                            \
-  85 /* Program base relative high
+  85 /* Program base relative high                                                                 \
              16 bit (MOVT).  */
 #define R_ARM_MOVW_BREL                                                                            \
-  86 /* Program base relative 16
+  86 /* Program base relative 16                                                                   \
              bit (MOVW).  */
 #define R_ARM_THM_MOVW_BREL_NC                                                                     \
-  87 /* Program base relative 16
+  87 /* Program base relative 16                                                                   \
              bit (Thumb32 MOVW).  */
 #define R_ARM_THM_MOVT_BREL                                                                        \
-  88 /* Program base relative high
+  88 /* Program base relative high                                                                 \
              16 bit (Thumb32 MOVT).  */
 #define R_ARM_THM_MOVW_BREL                                                                        \
-  89 /* Program base relative 16
+  89 /* Program base relative 16                                                                   \
              bit (Thumb32 MOVW).  */
 #define R_ARM_TLS_GOTDESC  90
 #define R_ARM_TLS_CALL     91
@@ -3185,48 +3185,48 @@ enum {
 #define R_ARM_GOT_ABS      95 /* GOT entry.  */
 #define R_ARM_GOT_PREL     96 /* PC relative GOT entry.  */
 #define R_ARM_GOT_BREL12                                                                           \
-  97 /* GOT entry relative to GOT
+  97 /* GOT entry relative to GOT                                                                  \
              origin (LDR).  */
 #define R_ARM_GOTOFF12                                                                             \
-  98 /* 12 bit, GOT entry relative
+  98 /* 12 bit, GOT entry relative                                                                 \
              to GOT origin (LDR, STR).  */
 #define R_ARM_GOTRELAX      99
 #define R_ARM_GNU_VTENTRY   100
 #define R_ARM_GNU_VTINHERIT 101
 #define R_ARM_THM_PC11      102 /* PC relative & 0xFFE (Thumb16 B).  */
 #define R_ARM_THM_PC9                                                                              \
-  103 /* PC relative & 0x1FE
+  103 /* PC relative & 0x1FE                                                                       \
              (Thumb16 B/B<cond>).  */
 #define R_ARM_TLS_GD32                                                                             \
-  104 /* PC-rel 32 bit for global dynamic
+  104 /* PC-rel 32 bit for global dynamic                                                          \
              thread local data */
 #define R_ARM_TLS_LDM32                                                                            \
-  105 /* PC-rel 32 bit for local dynamic
+  105 /* PC-rel 32 bit for local dynamic                                                           \
              thread local data */
 #define R_ARM_TLS_LDO32                                                                            \
-  106 /* 32 bit offset relative to TLS
+  106 /* 32 bit offset relative to TLS                                                             \
              block */
 #define R_ARM_TLS_IE32                                                                             \
-  107 /* PC-rel 32 bit for GOT entry of
+  107 /* PC-rel 32 bit for GOT entry of                                                            \
              static TLS block offset */
 #define R_ARM_TLS_LE32                                                                             \
-  108 /* 32 bit offset relative to static
+  108 /* 32 bit offset relative to static                                                          \
              TLS block */
 #define R_ARM_TLS_LDO12                                                                            \
-  109 /* 12 bit relative to TLS
+  109 /* 12 bit relative to TLS                                                                    \
              block (LDR, STR).  */
 #define R_ARM_TLS_LE12                                                                             \
-  110 /* 12 bit relative to static
+  110 /* 12 bit relative to static                                                                 \
              TLS block (LDR, STR).  */
 #define R_ARM_TLS_IE12GP                                                                           \
-  111                               /* 12 bit GOT entry relative
+  111                               /* 12 bit GOT entry relative                                   \
              to GOT origin (LDR).  */
 #define R_ARM_ME_TOO            128 /* Obsolete.  */
 #define R_ARM_THM_TLS_DESCSEQ   129
 #define R_ARM_THM_TLS_DESCSEQ16 129
 #define R_ARM_THM_TLS_DESCSEQ32 130
 #define R_ARM_THM_GOT_BREL12                                                                       \
-  131 /* GOT entry relative to GOT
+  131 /* GOT entry relative to GOT                                                                 \
              origin, 12 bit (Thumb32 LDR).  */
 #define R_ARM_IRELATIVE 160
 #define R_ARM_RXPC25    249
@@ -3540,63 +3540,63 @@ enum {
 #define R_390_PLTOFF64  36 /* 16 bit offset from GOT to PLT. */
 #define R_390_TLS_LOAD  37 /* Tag for load insn in TLS code.  */
 #define R_390_TLS_GDCALL                                                                           \
-  38 /* Tag for function call in general
+  38 /* Tag for function call in general                                                           \
              dynamic TLS code. */
 #define R_390_TLS_LDCALL                                                                           \
-  39 /* Tag for function call in local
+  39 /* Tag for function call in local                                                             \
              dynamic TLS code. */
 #define R_390_TLS_GD32                                                                             \
-  40 /* Direct 32 bit for general dynamic
+  40 /* Direct 32 bit for general dynamic                                                          \
              thread local data.  */
 #define R_390_TLS_GD64                                                                             \
-  41 /* Direct 64 bit for general dynamic
+  41 /* Direct 64 bit for general dynamic                                                          \
             thread local data.  */
 #define R_390_TLS_GOTIE12                                                                          \
-  42 /* 12 bit GOT offset for static TLS
+  42 /* 12 bit GOT offset for static TLS                                                           \
              block offset.  */
 #define R_390_TLS_GOTIE32                                                                          \
-  43 /* 32 bit GOT offset for static TLS
+  43 /* 32 bit GOT offset for static TLS                                                           \
              block offset.  */
 #define R_390_TLS_GOTIE64                                                                          \
-  44 /* 64 bit GOT offset for static TLS
+  44 /* 64 bit GOT offset for static TLS                                                           \
              block offset. */
 #define R_390_TLS_LDM32                                                                            \
-  45 /* Direct 32 bit for local dynamic
+  45 /* Direct 32 bit for local dynamic                                                            \
              thread local data in LE code.  */
 #define R_390_TLS_LDM64                                                                            \
-  46 /* Direct 64 bit for local dynamic
+  46 /* Direct 64 bit for local dynamic                                                            \
              thread local data in LE code.  */
 #define R_390_TLS_IE32                                                                             \
-  47 /* 32 bit address of GOT entry for
+  47 /* 32 bit address of GOT entry for                                                            \
              negated static TLS block offset.  */
 #define R_390_TLS_IE64                                                                             \
-  48 /* 64 bit address of GOT entry for
+  48 /* 64 bit address of GOT entry for                                                            \
              negated static TLS block offset.  */
 #define R_390_TLS_IEENT                                                                            \
-  49 /* 32 bit rel. offset to GOT entry for
+  49 /* 32 bit rel. offset to GOT entry for                                                        \
              negated static TLS block offset.  */
 #define R_390_TLS_LE32                                                                             \
-  50 /* 32 bit negated offset relative to
+  50 /* 32 bit negated offset relative to                                                          \
              static TLS block.  */
 #define R_390_TLS_LE64                                                                             \
-  51 /* 64 bit negated offset relative to
+  51 /* 64 bit negated offset relative to                                                          \
              static TLS block.  */
 #define R_390_TLS_LDO32                                                                            \
-  52 /* 32 bit offset relative to TLS
+  52 /* 32 bit offset relative to TLS                                                              \
              block.  */
 #define R_390_TLS_LDO64                                                                            \
-  53                        /* 64 bit offset relative to TLS
+  53                        /* 64 bit offset relative to TLS                                       \
              block.  */
 #define R_390_TLS_DTPMOD 54 /* ID of module containing symbol.  */
 #define R_390_TLS_DTPOFF 55 /* Offset in TLS block.	 */
 #define R_390_TLS_TPOFF                                                                            \
-  56                      /* Negated offset in static TLS
+  56                      /* Negated offset in static TLS                                          \
              block.  */
 #define R_390_20       57 /* Direct 20 bit.  */
 #define R_390_GOT20    58 /* 20 bit GOT offset.  */
 #define R_390_GOTPLT20 59 /* 20 bit offset to jump slot.  */
 #define R_390_TLS_GOTIE20                                                                          \
-  60                       /* 20 bit GOT offset for static TLS
+  60                       /* 20 bit GOT offset for static TLS                                     \
              block offset.  */
 #define R_390_IRELATIVE 61 /* STT_GNU_IFUNC relocation.  */
 /* Keep this the last entry.  */
@@ -3637,7 +3637,7 @@ enum {
 #define R_X86_64_JUMP_SLOT 7 /* Create PLT entry */
 #define R_X86_64_RELATIVE  8 /* Adjust by program base */
 #define R_X86_64_GOTPCREL                                                                          \
-  9                          /* 32 bit signed PC relative
+  9                          /* 32 bit signed PC relative                                          \
              offset to GOT */
 #define R_X86_64_32       10 /* Direct 32 bit zero extended */
 #define R_X86_64_32S      11 /* Direct 32 bit sign extended */
@@ -3649,35 +3649,35 @@ enum {
 #define R_X86_64_DTPOFF64 17 /* Offset in module's TLS block */
 #define R_X86_64_TPOFF64  18 /* Offset in initial TLS block */
 #define R_X86_64_TLSGD                                                                             \
-  19 /* 32 bit signed PC relative offset
+  19 /* 32 bit signed PC relative offset                                                           \
              to two GOT entries for GD symbol */
 #define R_X86_64_TLSLD                                                                             \
-  20                         /* 32 bit signed PC relative offset
+  20                         /* 32 bit signed PC relative offset                                   \
              to two GOT entries for LD symbol */
 #define R_X86_64_DTPOFF32 21 /* Offset in TLS block */
 #define R_X86_64_GOTTPOFF                                                                          \
-  22                         /* 32 bit signed PC relative offset
+  22                         /* 32 bit signed PC relative offset                                   \
              to GOT entry for IE symbol */
 #define R_X86_64_TPOFF32  23 /* Offset in initial TLS block */
 #define R_X86_64_PC64     24 /* PC relative 64 bit */
 #define R_X86_64_GOTOFF64 25 /* 64 bit offset to GOT */
 #define R_X86_64_GOTPC32                                                                           \
-  26                      /* 32 bit signed pc relative
+  26                      /* 32 bit signed pc relative                                             \
              offset to GOT */
 #define R_X86_64_GOT64 27 /* 64-bit GOT entry offset */
 #define R_X86_64_GOTPCREL64                                                                        \
-  28                         /* 64-bit PC relative offset
+  28                         /* 64-bit PC relative offset                                          \
              to GOT entry */
 #define R_X86_64_GOTPC64  29 /* 64-bit PC relative offset to GOT */
 #define R_X86_64_GOTPLT64 30 /* like GOT64, says PLT entry needed */
 #define R_X86_64_PLTOFF64                                                                          \
-  31                                /* 64-bit GOT relative offset
+  31                                /* 64-bit GOT relative offset                                  \
              to PLT entry */
 #define R_X86_64_SIZE32          32 /* Size of symbol plus 32-bit addend */
 #define R_X86_64_SIZE64          33 /* Size of symbol plus 64-bit addend */
 #define R_X86_64_GOTPC32_TLSDESC 34 /* GOT offset for TLS descriptor.  */
 #define R_X86_64_TLSDESC_CALL                                                                      \
-  35                           /* Marker for call through TLS
+  35                           /* Marker for call through TLS                                      \
              descriptor.  */
 #define R_X86_64_TLSDESC    36 /* TLS descriptor.  */
 #define R_X86_64_IRELATIVE  37 /* Adjust indirectly by program base */
@@ -3685,12 +3685,12 @@ enum {
                                /* 39 Reserved was R_X86_64_PC32_BND */
                                /* 40 Reserved was R_X86_64_PLT32_BND */
 #define R_X86_64_GOTPCRELX                                                                         \
-  41 /* Load from 32 bit signed pc relative
+  41 /* Load from 32 bit signed pc relative                                                        \
-					   offset to GOT entry without REX
+             offset to GOT entry without REX                                                       \
              prefix, relaxable.  */
 #define R_X86_64_REX_GOTPCRELX                                                                     \
-  42 /* Load from 32 bit signed pc relative
+  42 /* Load from 32 bit signed pc relative                                                        \
-					   offset to GOT entry with REX prefix,
+             offset to GOT entry with REX prefix,                                                  \
              relaxable.  */
 #define R_X86_64_NUM 43
 
@@ -3732,22 +3732,22 @@ enum {
 #define R_MN10300_TLS_LD        25 /* 32-bit offset for local dynamic.  */
 #define R_MN10300_TLS_LDO       26 /* Module-relative offset.  */
 #define R_MN10300_TLS_GOTIE                                                                        \
-  27 /* GOT offset for static TLS block
+  27 /* GOT offset for static TLS block                                                            \
              offset.  */
 #define R_MN10300_TLS_IE                                                                           \
-  28 /* GOT address for static TLS block
+  28 /* GOT address for static TLS block                                                           \
              offset.  */
 #define R_MN10300_TLS_LE                                                                           \
-  29                            /* Offset relative to static TLS
+  29                            /* Offset relative to static TLS                                   \
              block.  */
 #define R_MN10300_TLS_DTPMOD 30 /* ID of module containing symbol.  */
 #define R_MN10300_TLS_DTPOFF 31 /* Offset in module TLS block.  */
 #define R_MN10300_TLS_TPOFF  32 /* Offset in static TLS block.  */
 #define R_MN10300_SYM_DIFF                                                                         \
-  33 /* Adjustment for next reloc as needed
+  33 /* Adjustment for next reloc as needed                                                        \
              by linker relaxation.  */
 #define R_MN10300_ALIGN                                                                            \
-  34 /* Alignment requirement for linker
+  34 /* Alignment requirement for linker                                                           \
              relaxation.  */
 #define R_MN10300_NUM 35
 
@@ -3789,26 +3789,26 @@ enum {
 #define R_M32R_GOTOFF    54 /* 24 bit offset to GOT */
 #define R_M32R_GOTPC24   55 /* 24 bit PC relative offset to GOT */
 #define R_M32R_GOT16_HI_ULO                                                                        \
-  56 /* High 16 bit GOT entry with unsigned
+  56 /* High 16 bit GOT entry with unsigned                                                        \
              low */
 #define R_M32R_GOT16_HI_SLO                                                                        \
-  57                       /* High 16 bit GOT entry with signed
+  57                       /* High 16 bit GOT entry with signed                                    \
              low */
 #define R_M32R_GOT16_LO 58 /* Low 16 bit GOT entry */
 #define R_M32R_GOTPC_HI_ULO                                                                        \
-  59 /* High 16 bit PC relative offset to
+  59 /* High 16 bit PC relative offset to                                                          \
              GOT with unsigned low */
 #define R_M32R_GOTPC_HI_SLO                                                                        \
-  60 /* High 16 bit PC relative offset to
+  60 /* High 16 bit PC relative offset to                                                          \
              GOT with signed low */
 #define R_M32R_GOTPC_LO                                                                            \
-  61 /* Low 16 bit PC relative offset to
+  61 /* Low 16 bit PC relative offset to                                                           \
              GOT */
 #define R_M32R_GOTOFF_HI_ULO                                                                       \
-  62 /* High 16 bit offset to GOT
+  62 /* High 16 bit offset to GOT                                                                  \
              with unsigned low */
 #define R_M32R_GOTOFF_HI_SLO                                                                       \
-  63                         /* High 16 bit offset to GOT
+  63                         /* High 16 bit offset to GOT                                          \
              with signed low */
 #define R_M32R_GOTOFF_LO 64  /* Low 16 bit offset to GOT */
 #define R_M32R_NUM       256 /* Keep this the last entry. */
@@ -3871,7 +3871,7 @@ enum {
 #define R_NIOS2_CJMP          19 /* Conditional branch.  */
 #define R_NIOS2_CALLR         20 /* Indirect call through register.  */
 #define R_NIOS2_ALIGN                                                                              \
-  21                           /* Alignment requirement for
+  21                           /* Alignment requirement for                                        \
              linker relaxation.  */
 #define R_NIOS2_GOT16       22 /* 16 bit GOT entry.  */
 #define R_NIOS2_CALL16      23 /* 16 bit GOT entry for function.  */
@@ -4195,7 +4195,7 @@ enum {
 
 /* RISC-V specific values for the st_other field.  */
 #define STO_RISCV_VARIANT_CC                                                                       \
-  0x80 /* Function uses variant calling
+  0x80 /* Function uses variant calling                                                            \
              convention */
 
 /* RISC-V specific values for the sh_type field.  */
@@ -4545,4 +4545,11 @@ enum {
 #define R_OR1K_TLS_DTPOFF    33
 #define R_OR1K_TLS_DTPMOD    34
 
+struct elf_aux {
+  uint64_t entry;
+  uint64_t phdr;
+  uint64_t phent;
+  uint64_t phnum;
+};
+
 #endif // _KERNELAUX_ELF_H

kernel/generic/flags.mk

@@ -8,7 +8,7 @@ cflags += -nostdinc \
 					-Wextra \
 					-mcmodel=kernel
 
-cflags += -isystem . -isystem c_headers/include
+cflags += -isystem . -isystem ../include
 
 cflags += -DPRINTF_INCLUDE_CONFIG_H=1 \
 					-D_ALLOC_SKIP_DEFINE

kernel/irq/irq.c

@@ -3,18 +3,20 @@
 #include <libk/std.h>
 #include <mm/liballoc.h>
 #include <sync/spin_lock.h>
+#include <sys/debug.h>
 
 #if defined(__x86_64__)
 #include <amd64/apic.h>
 #include <amd64/intr.h>
 #endif
 
-/* TODO: figure out a generic way to work with IRQs */
+struct irq* irq_table[0x100];
 
-static struct irq* irqs = NULL;
+static spin_lock_t irqs_lock = SPIN_LOCK_INIT;
-static spin_lock_t irqs_lock;
+
+bool irq_attach (void (*func) (void*, void*), void* arg, uint32_t irq_num) {
+  spin_lock_ctx_t ctxiqa;
 
-bool irq_attach (void (*func) (void*, void*), void* arg, uint32_t irq_num, uint32_t flags) {
   struct irq* irq = malloc (sizeof (*irq));
   if (irq == NULL) {
     return false;
@@ -23,44 +25,22 @@ bool irq_attach (void (*func) (void*, void*), void* arg, uint32_t irq_num, uint3
   irq->func = func;
   irq->arg = arg;
   irq->irq_num = irq_num;
-  irq->flags = flags;
 
-  spin_lock (&irqs_lock);
+  spin_lock (&irqs_lock, &ctxiqa);
-  linklist_append (struct irq*, irqs, irq);
+  irq_table[irq_num] = irq;
-  spin_unlock (&irqs_lock);
+  spin_unlock (&irqs_lock, &ctxiqa);
-
-#if defined(__x86_64__)
-  uint8_t resolution = amd64_resolve_irq (irq_num);
-  amd64_ioapic_route_irq (irq_num, resolution, 0, amd64_lapic_id ());
-#endif
 
   return true;
 }
 
-void irq_detach (void (*func) (void*, void*)) {
-  spin_lock (&irqs_lock);
-
-  struct irq *irq, *irq_tmp;
-  linklist_foreach (irqs, irq, irq_tmp) {
-    if ((uintptr_t)irq->func == (uintptr_t)func)
-      linklist_remove (struct irq*, irqs, irq);
-  }
-
-  spin_unlock (&irqs_lock);
-}
-
 struct irq* irq_find (uint32_t irq_num) {
-  spin_lock (&irqs_lock);
+  spin_lock_ctx_t ctxiqa;
+
+  spin_lock (&irqs_lock, &ctxiqa);
+
+  struct irq* irq = irq_table[irq_num];
+
+  spin_unlock (&irqs_lock, &ctxiqa);
 
-  struct irq *irq, *irq_tmp;
-  linklist_foreach (irqs, irq, irq_tmp) {
-    if (irq->irq_num == irq_num) {
-      spin_unlock (&irqs_lock);
   return irq;
 }
-  }
-
-  spin_unlock (&irqs_lock);
-
-  return NULL;
-}

kernel/irq/irq.h

@@ -1,23 +1,20 @@
 #ifndef _KERNEL_IRQ_IRQ_H
 #define _KERNEL_IRQ_IRQ_H
 
+#include <libk/list.h>
 #include <libk/std.h>
 
-#define IRQ_INTERRUPT_SAFE (1 << 0)
-
 typedef void (*irq_func_t) (void* arg, void* regs);
 
 struct irq {
-  struct irq* next;
+  struct list_node_link irqs_link;
 
   irq_func_t func;
   void* arg;
   uint32_t irq_num;
-  uint32_t flags;
 };
 
-bool irq_attach (irq_func_t, void* arg, uint32_t irq_num, uint32_t flags);
+bool irq_attach (irq_func_t, void* arg, uint32_t irq_num);
-void irq_detach (irq_func_t func);
 struct irq* irq_find (uint32_t irq_num);
 
 #endif // _KERNEL_IRQ_IRQ_H

kernel/libk/assert.h

@@ -0,0 +1,15 @@
+#ifndef _KERNEL_LIBK_ASSERT_H
+#define _KERNEL_LIBK_ASSERT_H
+
+#include <sys/spin.h>
+
+#define assert(x)                                                                                  \
+  do {                                                                                             \
+    if (!(x)) {                                                                                    \
+      DEBUG ("%s ssertion failed\n", #x);                                                          \
+      spin ();                                                                                     \
+      __builtin_unreachable ();                                                                    \
+    }                                                                                              \
+  } while (0)
+
+#endif // _KERNEL_LIBK_ASSERT_H

kernel/libk/list.h

@@ -1,12 +1,19 @@
 #ifndef _KERNEL_LIBK_LIST_H
 #define _KERNEL_LIBK_LIST_H
 
-#define dlinklist_append(type, head, new)                                                          \
+struct list_node_link {
+  struct list_node_link* next;
+  struct list_node_link* prev;
+};
+
+#define list_entry(ptr, type, member) ((type*)((char*)(ptr) - offsetof (type, member)))
+
+#define list_append(head, new)                                                                     \
   do {                                                                                             \
     if ((new) != NULL) {                                                                           \
       (new)->next = NULL;                                                                          \
       if ((head) != NULL) {                                                                        \
-        type __tmp = (head);                                                                       \
+        struct list_node_link* __tmp = (head);                                                     \
         while (__tmp->next != NULL) {                                                              \
           __tmp = __tmp->next;                                                                     \
         }                                                                                          \
@@ -19,7 +26,7 @@
     }                                                                                              \
   } while (0)
 
-#define dlinklist_prepend(head, new)                                                               \
+#define list_prepend(head, new)                                                                    \
   do {                                                                                             \
     if ((new) != NULL) {                                                                           \
       (new)->prev = NULL;                                                                          \
@@ -31,7 +38,7 @@
     }                                                                                              \
   } while (0)
 
-#define dlinklist_remove(head, ele)                                                                \
+#define list_remove(head, ele)                                                                     \
   do {                                                                                             \
     if ((ele) != NULL) {                                                                           \
       if ((ele)->prev != NULL) {                                                                   \
@@ -47,10 +54,10 @@
     }                                                                                              \
   } while (0)
 
-#define dlinklist_find(type, head, out, propname, propvalue)                                       \
+#define list_find(head, out, propname, propvalue)                                                  \
   do {                                                                                             \
     (out) = NULL;                                                                                  \
-    type __tmp = (head);                                                                           \
+    struct list_node_link* __tmp = (head);                                                         \
     while (__tmp) {                                                                                \
       if (__tmp->propname == (propvalue)) {                                                        \
         (out) = __tmp;                                                                             \
@@ -60,23 +67,23 @@
     }                                                                                              \
   } while (0)
 
-#define dlinklist_foreach(head, var, tmp)                                                          \
+#define list_foreach(head, var, tmp)                                                               \
   for (var = (head), tmp = (var ? var->next : NULL); var != NULL;                                  \
        var = tmp, tmp = (var ? var->next : NULL))
 
-#define dlinklist_foreach_index(head, var, tmp, idx)                                               \
+#define list_foreach_index(head, var, tmp, idx)                                                    \
   for ((idx) = 0, var = (head), tmp = (var ? var->next : NULL); var != NULL;                       \
        var = tmp, tmp = (var ? var->next : NULL), (idx)++)
 
-#define dlinklist_foreach_index_limit(head, var, tmp, idx, max)                                    \
+#define list_foreach_index_limit(head, var, tmp, idx, max)                                         \
   for ((idx) = 0, var = (head), tmp = (var ? var->next : NULL); var != NULL && (idx) < (max);      \
        var = tmp, tmp = (var ? var->next : NULL), (idx)++)
 
-#define dlinklist_back(type, head, out)                                                            \
+#define list_back(head, out)                                                                       \
   do {                                                                                             \
     (out) = NULL;                                                                                  \
     if ((head) != NULL) {                                                                          \
-      type __tmp = (head);                                                                         \
+      struct list_node_link* __tmp = (head);                                                       \
       while (__tmp->next != NULL) {                                                                \
         __tmp = __tmp->next;                                                                       \
       }                                                                                            \
@@ -84,11 +91,11 @@
     }                                                                                              \
   } while (0)
 
-#define dlinklist_front(type, head, out)                                                           \
+#define list_front(head, out)                                                                      \
   do {                                                                                             \
     (out) = NULL;                                                                                  \
     if ((head) != NULL) {                                                                          \
-      type __tmp = (head);                                                                         \
+      struct list_node_link* __tmp = (head);                                                       \
       while (__tmp->prev != NULL) {                                                                \
         __tmp = __tmp->prev;                                                                       \
       }                                                                                            \
@@ -96,7 +103,7 @@
     }                                                                                              \
   } while (0)
 
-#define dlinklist_insert_after(head, pos, new)                                                     \
+#define list_insert_after(head, pos, new)                                                          \
   do {                                                                                             \
     if ((pos) != NULL && (new) != NULL) {                                                          \
       (new)->prev = (pos);                                                                         \
@@ -112,7 +119,7 @@
     }                                                                                              \
   } while (0)
 
-#define dlinklist_insert_before(head, pos, new)                                                    \
+#define list_insert_before(head, pos, new)                                                         \
   do {                                                                                             \
     if ((pos) != NULL && (new) != NULL) {                                                          \
       (new)->next = (pos);                                                                         \
@@ -130,11 +137,11 @@
     }                                                                                              \
   } while (0)
 
-#define dlinklist_index_of(type, head, ele, out_idx)                                               \
+#define list_index_of(head, ele, out_idx)                                                          \
   do {                                                                                             \
     (out_idx) = -1;                                                                                \
     int __idx = 0;                                                                                 \
-    type __tmp = (head);                                                                           \
+    struct list_node_link* __tmp = (head);                                                         \
     while (__tmp != NULL) {                                                                        \
       if (__tmp == (ele)) {                                                                        \
         (out_idx) = __idx;                                                                         \
@@ -145,11 +152,11 @@
     }                                                                                              \
   } while (0)
 
-#define dlinklist_index_of_prop(type, head, propname, propvalue, out_idx)                          \
+#define list_index_of_prop(head, propname, propvalue, out_idx)                                     \
   do {                                                                                             \
     (out_idx) = -1;                                                                                \
     int __idx = 0;                                                                                 \
-    type __tmp = (head);                                                                           \
+    struct list_node_link* __tmp = (head);                                                         \
     while (__tmp != NULL) {                                                                        \
       if (__tmp->propname == (propvalue)) {                                                        \
         (out_idx) = __idx;                                                                         \
@@ -160,109 +167,4 @@
     }                                                                                              \
   } while (0)
 
-#define linklist_index_of(type, head, ele, out_idx)                                                \
-  do {                                                                                             \
-    (out_idx) = -1;                                                                                \
-    int __idx = 0;                                                                                 \
-    type __tmp = (head);                                                                           \
-    while (__tmp != NULL) {                                                                        \
-      if (__tmp == (ele)) {                                                                        \
-        (out_idx) = __idx;                                                                         \
-        break;                                                                                     \
-      }                                                                                            \
-      __tmp = __tmp->next;                                                                         \
-      __idx++;                                                                                     \
-    }                                                                                              \
-  } while (0)
-
-#define linklist_index_of_prop(type, head, propname, propvalue, out_idx)                           \
-  do {                                                                                             \
-    (out_idx) = -1;                                                                                \
-    int __idx = 0;                                                                                 \
-    type __tmp = (head);                                                                           \
-    while (__tmp != NULL) {                                                                        \
-      if (__tmp->propname == (propvalue)) {                                                        \
-        (out_idx) = __idx;                                                                         \
-        break;                                                                                     \
-      }                                                                                            \
-      __tmp = __tmp->next;                                                                         \
-      __idx++;                                                                                     \
-    }                                                                                              \
-  } while (0)
-
-#define linklist_append(type, head, new)                                                           \
-  do {                                                                                             \
-    if ((new) != NULL) {                                                                           \
-      if ((head) != NULL) {                                                                        \
-        type __tmp;                                                                                \
-        (new)->next = NULL;                                                                        \
-        __tmp = (head);                                                                            \
-        while (__tmp->next != NULL) {                                                              \
-          __tmp = __tmp->next;                                                                     \
-        }                                                                                          \
-        __tmp->next = (new);                                                                       \
-      } else {                                                                                     \
-        (new)->next = NULL;                                                                        \
-        (head) = (new);                                                                            \
-      }                                                                                            \
-    }                                                                                              \
-  } while (0)
-
-#define linklist_remove(type, head, ele)                                                           \
-  do {                                                                                             \
-    if ((head) != NULL && (ele) != NULL) {                                                         \
-      type __cur = (head);                                                                         \
-      type __prev = NULL;                                                                          \
-      while (__cur != NULL && __cur != (ele)) {                                                    \
-        __prev = __cur;                                                                            \
-        __cur = __cur->next;                                                                       \
-      }                                                                                            \
-      if (__cur == (ele)) {                                                                        \
-        if (__prev != NULL) {                                                                      \
-          __prev->next = __cur->next;                                                              \
-        } else {                                                                                   \
-          (head) = __cur->next;                                                                    \
-        }                                                                                          \
-        (ele)->next = NULL;                                                                        \
-      }                                                                                            \
-    }                                                                                              \
-  } while (0)
-
-#define linklist_find(type, head, out, propname, propvalue)                                        \
-  do {                                                                                             \
-    (out) = NULL;                                                                                  \
-    type __tmp = (head);                                                                           \
-    while (__tmp) {                                                                                \
-      if (__tmp->propname == (propvalue)) {                                                        \
-        (out) = __tmp;                                                                             \
-        break;                                                                                     \
-      }                                                                                            \
-      __tmp = __tmp->next;                                                                         \
-    }                                                                                              \
-  } while (0)
-
-#define linklist_foreach(head, var, tmp)                                                           \
-  for (var = (head), tmp = (var ? var->next : NULL); var != NULL;                                  \
-       var = tmp, tmp = (var ? var->next : NULL))
-
-#define linklist_foreach_index(head, var, tmp, idx)                                                \
-  for ((idx) = 0, var = (head), tmp = (var ? var->next : NULL); var != NULL;                       \
-       var = tmp, tmp = (var ? var->next : NULL), (idx)++)
-
-#define linklist_foreach_index_limit(head, var, tmp, idx, max)                                     \
-  for ((idx) = 0, var = (head), tmp = (var ? var->next : NULL); var != NULL && (idx) < (max);      \
-       var = tmp, tmp = (var ? var->next : NULL), (idx)++)
-
-#define linklist_back(type, head, out)                                                             \
-  do {                                                                                             \
-    (out) = NULL;                                                                                  \
-    if ((head) != NULL) {                                                                          \
-      type __tmp = (head);                                                                         \
-      while (__tmp->next != NULL) {                                                                \
-        __tmp = __tmp->next;                                                                       \
-      }                                                                                            \
-      (out) = __tmp;                                                                               \
-    }                                                                                              \
-  } while (0)
-
 #endif // _KERNEL_LIBK_LIST_H

kernel/libk/rbtree.h

@@ -0,0 +1,323 @@
+#ifndef _KERNEL_LIBK_RBTREE_H
+#define _KERNEL_LIBK_RBTREE_H
+
+struct rb_node_link {
+  struct rb_node_link* left;
+  struct rb_node_link* right;
+  struct rb_node_link* parent;
+  int color;
+};
+
+#define RBTREE_RED   0
+#define RBTREE_BLACK 1
+
+#define rbtree_parent(x) ((x)->parent)
+#define rbtree_left(x)   ((x)->left)
+#define rbtree_right(x)  ((x)->right)
+#define rbtree_color(x)  ((x)->color)
+
+#define rbtree_entry(node, type, member) ((type*)((char*)(node) - offsetof (type, member)))
+
+#define rbtree_node_color(x) ((x) ? (x)->color : RBTREE_BLACK)
+
+#define rbtree_rotate_left(root_ptr, x_node)                                                       \
+  do {                                                                                             \
+    struct rb_node_link* __x = (x_node);                                                           \
+    struct rb_node_link* __y = __x->right;                                                         \
+    __x->right = __y->left;                                                                        \
+    if (__y->left)                                                                                 \
+      __y->left->parent = __x;                                                                     \
+    __y->parent = __x->parent;                                                                     \
+    if (!__x->parent)                                                                              \
+      *(root_ptr) = __y;                                                                           \
+    else if (__x == __x->parent->left)                                                             \
+      __x->parent->left = __y;                                                                     \
+    else                                                                                           \
+      __x->parent->right = __y;                                                                    \
+    __y->left = __x;                                                                               \
+    __x->parent = __y;                                                                             \
+  } while (0)
+
+#define rbtree_rotate_right(root_ptr, y_node)                                                      \
+  do {                                                                                             \
+    struct rb_node_link* __y = (y_node);                                                           \
+    struct rb_node_link* __x = __y->left;                                                          \
+    __y->left = __x->right;                                                                        \
+    if (__x->right)                                                                                \
+      __x->right->parent = __y;                                                                    \
+    __x->parent = __y->parent;                                                                     \
+    if (!__y->parent)                                                                              \
+      *(root_ptr) = __x;                                                                           \
+    else if (__y == __y->parent->right)                                                            \
+      __y->parent->right = __x;                                                                    \
+    else                                                                                           \
+      __y->parent->left = __x;                                                                     \
+    __x->right = __y;                                                                              \
+    __y->parent = __x;                                                                             \
+  } while (0)
+
+#define rbtree_insert_fixup(root_ptr, z_node)                                                      \
+  do {                                                                                             \
+    struct rb_node_link* __z = (z_node);                                                           \
+    while (__z->parent && __z->parent->color == RBTREE_RED) {                                      \
+      if (__z->parent == __z->parent->parent->left) {                                              \
+        struct rb_node_link* __y = __z->parent->parent->right;                                     \
+        if (rbtree_node_color (__y) == RBTREE_RED) {                                               \
+          __z->parent->color = RBTREE_BLACK;                                                       \
+          __y->color = RBTREE_BLACK;                                                               \
+          __z->parent->parent->color = RBTREE_RED;                                                 \
+          __z = __z->parent->parent;                                                               \
+        } else {                                                                                   \
+          if (__z == __z->parent->right) {                                                         \
+            __z = __z->parent;                                                                     \
+            rbtree_rotate_left (root_ptr, __z);                                                    \
+          }                                                                                        \
+          __z->parent->color = RBTREE_BLACK;                                                       \
+          __z->parent->parent->color = RBTREE_RED;                                                 \
+          rbtree_rotate_right (root_ptr, __z->parent->parent);                                     \
+        }                                                                                          \
+      } else {                                                                                     \
+        struct rb_node_link* __y = __z->parent->parent->left;                                      \
+        if (rbtree_node_color (__y) == RBTREE_RED) {                                               \
+          __z->parent->color = RBTREE_BLACK;                                                       \
+          __y->color = RBTREE_BLACK;                                                               \
+          __z->parent->parent->color = RBTREE_RED;                                                 \
+          __z = __z->parent->parent;                                                               \
+        } else {                                                                                   \
+          if (__z == __z->parent->left) {                                                          \
+            __z = __z->parent;                                                                     \
+            rbtree_rotate_right (root_ptr, __z);                                                   \
+          }                                                                                        \
+          __z->parent->color = RBTREE_BLACK;                                                       \
+          __z->parent->parent->color = RBTREE_RED;                                                 \
+          rbtree_rotate_left (root_ptr, __z->parent->parent);                                      \
+        }                                                                                          \
+      }                                                                                            \
+    }                                                                                              \
+    (*(root_ptr))->color = RBTREE_BLACK;                                                           \
+  } while (0)
+
+#define rbtree_insert(type, root_ptr, node, member, keyfield)                                      \
+  do {                                                                                             \
+    struct rb_node_link** __link = (root_ptr);                                                     \
+    struct rb_node_link* __parent = NULL;                                                          \
+    struct rb_node_link* __new = (node);                                                           \
+    type* __nobj = rbtree_entry (__new, type, member);                                             \
+    while (*__link) {                                                                              \
+      __parent = *__link;                                                                          \
+      type* __xobj = rbtree_entry (*__link, type, member);                                         \
+      if (__nobj->keyfield < __xobj->keyfield)                                                     \
+        __link = &((*__link)->left);                                                               \
+      else                                                                                         \
+        __link = &((*__link)->right);                                                              \
+    }                                                                                              \
+    __new->parent = __parent;                                                                      \
+    __new->left = __new->right = NULL;                                                             \
+    __new->color = RBTREE_RED;                                                                     \
+    *__link = __new;                                                                               \
+    rbtree_insert_fixup (root_ptr, __new);                                                         \
+  } while (0)
+
+#define rbtree_find(type, root_ptr, keyval, out, member, keyfield)                                 \
+  do {                                                                                             \
+    (out) = NULL;                                                                                  \
+    struct rb_node_link* __cur = *(root_ptr);                                                      \
+    while (__cur) {                                                                                \
+      type* __obj = rbtree_entry (__cur, type, member);                                            \
+      if ((keyval) == __obj->keyfield) {                                                           \
+        (out) = rbtree_entry (__cur, type, member);                                                \
+        break;                                                                                     \
+      } else if ((keyval) < __obj->keyfield)                                                       \
+        __cur = __cur->left;                                                                       \
+      else                                                                                         \
+        __cur = __cur->right;                                                                      \
+    }                                                                                              \
+  } while (0)
+
+#define rbtree_min(node, out)                                                                      \
+  do {                                                                                             \
+    (out) = NULL;                                                                                  \
+    struct rb_node_link* __n = (node);                                                             \
+    while (__n && __n->left)                                                                       \
+      __n = __n->left;                                                                             \
+    (out) = __n;                                                                                   \
+  } while (0)
+
+#define rbtree_max(node, out)                                                                      \
+  do {                                                                                             \
+    (out) = NULL;                                                                                  \
+    struct rb_node_link* __n = (node);                                                             \
+    while (__n && __n->right)                                                                      \
+      __n = __n->right;                                                                            \
+    (out) = __n;                                                                                   \
+  } while (0)
+
+#define rbtree_first(root_ptr, out) rbtree_min (*(root_ptr), out)
+#define rbtree_last(root_ptr, out)  rbtree_max (*(root_ptr), out)
+
+#define rbtree_transplant(root_ptr, u_node, v_node)                                                \
+  do {                                                                                             \
+    struct rb_node_link* __u = (u_node);                                                           \
+    struct rb_node_link* __v = (v_node);                                                           \
+    if (!__u->parent)                                                                              \
+      *(root_ptr) = __v;                                                                           \
+    else if (__u == __u->parent->left)                                                             \
+      __u->parent->left = __v;                                                                     \
+    else                                                                                           \
+      __u->parent->right = __v;                                                                    \
+    if (__v)                                                                                       \
+      __v->parent = __u->parent;                                                                   \
+  } while (0)
+
+#define rbtree_delete_fixup(root_ptr, x_node, xparent_node)                                        \
+  do {                                                                                             \
+    struct rb_node_link* __rdf_x = (x_node);                                                       \
+    struct rb_node_link* __rdf_xp = (xparent_node);                                                \
+    while (__rdf_xp && (__rdf_x == NULL || __rdf_x->color == RBTREE_BLACK)) {                      \
+      if (__rdf_x == __rdf_xp->left) {                                                             \
+        struct rb_node_link* __w = __rdf_xp->right;                                                \
+        if (rbtree_node_color (__w) == RBTREE_RED) {                                               \
+          __w->color = RBTREE_BLACK;                                                               \
+          __rdf_xp->color = RBTREE_RED;                                                            \
+          rbtree_rotate_left (root_ptr, __rdf_xp);                                                 \
+          __w = __rdf_xp->right;                                                                   \
+        }                                                                                          \
+        if (rbtree_node_color (__w->left) == RBTREE_BLACK &&                                       \
+            rbtree_node_color (__w->right) == RBTREE_BLACK) {                                      \
+          if (__w)                                                                                 \
+            __w->color = RBTREE_RED;                                                               \
+          __rdf_x = __rdf_xp;                                                                      \
+          __rdf_xp = __rdf_x->parent;                                                              \
+        } else {                                                                                   \
+          if (rbtree_node_color (__w->right) == RBTREE_BLACK) {                                    \
+            if (__w->left)                                                                         \
+              __w->left->color = RBTREE_BLACK;                                                     \
+            __w->color = RBTREE_RED;                                                               \
+            rbtree_rotate_right (root_ptr, __w);                                                   \
+            __w = __rdf_xp->right;                                                                 \
+          }                                                                                        \
+          __w->color = __rdf_xp->color;                                                            \
+          __rdf_xp->color = RBTREE_BLACK;                                                          \
+          if (__w->right)                                                                          \
+            __w->right->color = RBTREE_BLACK;                                                      \
+          rbtree_rotate_left (root_ptr, __rdf_xp);                                                 \
+          __rdf_x = *(root_ptr);                                                                   \
+          break;                                                                                   \
+        }                                                                                          \
+      } else {                                                                                     \
+        struct rb_node_link* __w = __rdf_xp->left;                                                 \
+        if (rbtree_node_color (__w) == RBTREE_RED) {                                               \
+          __w->color = RBTREE_BLACK;                                                               \
+          __rdf_xp->color = RBTREE_RED;                                                            \
+          rbtree_rotate_right (root_ptr, __rdf_xp);                                                \
+          __w = __rdf_xp->left;                                                                    \
+        }                                                                                          \
+        if (rbtree_node_color (__w->right) == RBTREE_BLACK &&                                      \
+            rbtree_node_color (__w->left) == RBTREE_BLACK) {                                       \
+          if (__w)                                                                                 \
+            __w->color = RBTREE_RED;                                                               \
+          __rdf_x = __rdf_xp;                                                                      \
+          __rdf_xp = __rdf_x->parent;                                                              \
+        } else {                                                                                   \
+          if (rbtree_node_color (__w->left) == RBTREE_BLACK) {                                     \
+            if (__w->right)                                                                        \
+              __w->right->color = RBTREE_BLACK;                                                    \
+            __w->color = RBTREE_RED;                                                               \
+            rbtree_rotate_left (root_ptr, __w);                                                    \
+            __w = __rdf_xp->left;                                                                  \
+          }                                                                                        \
+          __w->color = __rdf_xp->color;                                                            \
+          __rdf_xp->color = RBTREE_BLACK;                                                          \
+          if (__w->left)                                                                           \
+            __w->left->color = RBTREE_BLACK;                                                       \
+          rbtree_rotate_right (root_ptr, __rdf_xp);                                                \
+          __rdf_x = *(root_ptr);                                                                   \
+          break;                                                                                   \
+        }                                                                                          \
+      }                                                                                            \
+    }                                                                                              \
+    if (__rdf_x)                                                                                   \
+      __rdf_x->color = RBTREE_BLACK;                                                               \
+  } while (0)
+
+#define rbtree_delete(root_ptr, z_node)                                                            \
+  do {                                                                                             \
+    struct rb_node_link* __rd_z = (z_node);                                                        \
+    struct rb_node_link* __rd_y = __rd_z;                                                          \
+    struct rb_node_link* __rd_x = NULL;                                                            \
+    struct rb_node_link* __rd_xp = NULL;                                                           \
+    int __rd_y_orig_color = __rd_y->color;                                                         \
+    if (!__rd_z->left) {                                                                           \
+      __rd_x = __rd_z->right;                                                                      \
+      __rd_xp = __rd_z->parent;                                                                    \
+      rbtree_transplant (root_ptr, __rd_z, __rd_z->right);                                         \
+    } else if (!__rd_z->right) {                                                                   \
+      __rd_x = __rd_z->left;                                                                       \
+      __rd_xp = __rd_z->parent;                                                                    \
+      rbtree_transplant (root_ptr, __rd_z, __rd_z->left);                                          \
+    } else {                                                                                       \
+      rbtree_min (__rd_z->right, __rd_y);                                                          \
+      __rd_y_orig_color = __rd_y->color;                                                           \
+      __rd_x = __rd_y->right;                                                                      \
+      if (__rd_y->parent == __rd_z) {                                                              \
+        __rd_xp = __rd_y;                                                                          \
+        if (__rd_x)                                                                                \
+          __rd_x->parent = __rd_y;                                                                 \
+      } else {                                                                                     \
+        __rd_xp = __rd_y->parent;                                                                  \
+        rbtree_transplant (root_ptr, __rd_y, __rd_y->right);                                       \
+        __rd_y->right = __rd_z->right;                                                             \
+        __rd_y->right->parent = __rd_y;                                                            \
+      }                                                                                            \
+      rbtree_transplant (root_ptr, __rd_z, __rd_y);                                                \
+      __rd_y->left = __rd_z->left;                                                                 \
+      __rd_y->left->parent = __rd_y;                                                               \
+      __rd_y->color = __rd_z->color;                                                               \
+    }                                                                                              \
+    if (__rd_y_orig_color == RBTREE_BLACK)                                                         \
+      rbtree_delete_fixup (root_ptr, __rd_x, __rd_xp);                                             \
+  } while (0)
+
+#define rbtree_next(node, out)                                                                     \
+  do {                                                                                             \
+    (out) = NULL;                                                                                  \
+    if (node) {                                                                                    \
+      if ((node)->right) {                                                                         \
+        struct rb_node_link* __n = (node)->right;                                                  \
+        while (__n->left)                                                                          \
+          __n = __n->left;                                                                         \
+        (out) = __n;                                                                               \
+      } else {                                                                                     \
+        struct rb_node_link* __n = (node);                                                         \
+        struct rb_node_link* __p = (node)->parent;                                                 \
+        while (__p && __n == __p->right) {                                                         \
+          __n = __p;                                                                               \
+          __p = __p->parent;                                                                       \
+        }                                                                                          \
+        (out) = __p;                                                                               \
+      }                                                                                            \
+    }                                                                                              \
+  } while (0)
+
+#define rbtree_prev(node, out)                                                                     \
+  do {                                                                                             \
+    (out) = NULL;                                                                                  \
+    if (node) {                                                                                    \
+      if ((node)->left) {                                                                          \
+        struct rb_node_link* __n = (node)->left;                                                   \
+        while (__n->right)                                                                         \
+          __n = __n->right;                                                                        \
+        (out) = __n;                                                                               \
+      } else {                                                                                     \
+        struct rb_node_link* __n = (node);                                                         \
+        struct rb_node_link* __p = (node)->parent;                                                 \
+        while (__p && __n == __p->left) {                                                          \
+          __n = __p;                                                                               \
+          __p = __p->parent;                                                                       \
+        }                                                                                          \
+        (out) = __p;                                                                               \
+      }                                                                                            \
+    }                                                                                              \
+  } while (0)
+
+#endif // _KERNEL_LIBK_RBTREE_H

kernel/libk/string.h

@@ -1,6 +1,8 @@
 #ifndef _KERNEL_LIBK_STRING_H
 #define _KERNEL_LIBK_STRING_H
 
+#include <libk/std.h>
+
 size_t memset (void* dst, uint8_t b, size_t n);
 size_t memcpy (void* dst, const void* src, size_t n);
 void strncpy (char* dst, const char* src, size_t n);

kernel/limine/requests.c

@@ -20,3 +20,4 @@ DECL_REQ (memmap, MEMMAP);
 DECL_REQ (rsdp, RSDP);
 DECL_REQ (mp, MP);
 DECL_REQ (module, MODULE);
+DECL_REQ (framebuffer, FRAMEBUFFER);

kernel/limine/requests.h

@@ -10,5 +10,6 @@ EXTERN_REQ (memmap);
 EXTERN_REQ (rsdp);
 EXTERN_REQ (mp);
 EXTERN_REQ (module);
+EXTERN_REQ (framebuffer);
 
 #endif // _KERNEL_LIMINE_REQUESTS_H

kernel/mm/liballoc.c

@@ -11,13 +11,13 @@
 
 spin_lock_t _liballoc_lock = SPIN_LOCK_INIT;
 
-int liballoc_lock (void) {
+int liballoc_lock (void* ctx) {
-  spin_lock (&_liballoc_lock);
+  spin_lock (&_liballoc_lock, (spin_lock_ctx_t*)ctx);
   return 0;
 }
 
-int liballoc_unlock (void) {
+int liballoc_unlock (void* ctx) {
-  spin_unlock (&_liballoc_lock);
+  spin_unlock (&_liballoc_lock, (spin_lock_ctx_t*)ctx);
   return 0;
 }
 
@@ -243,8 +243,9 @@ void* malloc (size_t size) {
   int index;
   void* ptr;
   struct boundary_tag* tag = NULL;
+  spin_lock_ctx_t ctxliba;
 
-  liballoc_lock ();
+  liballoc_lock (&ctxliba);
 
   if (l_initialized == 0) {
     for (index = 0; index < MAXEXP; index++) {
@@ -272,7 +273,7 @@ void* malloc (size_t size) {
   // No page found. Make one.
   if (tag == NULL) {
     if ((tag = allocate_new_tag (size)) == NULL) {
-      liballoc_unlock ();
+      liballoc_unlock (&ctxliba);
       return NULL;
     }
 
@@ -305,23 +306,24 @@ void* malloc (size_t size) {
 
   ptr = (void*)((uintptr_t)tag + sizeof (struct boundary_tag));
 
-  liballoc_unlock ();
+  liballoc_unlock (&ctxliba);
   return ptr;
 }
 
 void free (void* ptr) {
   int index;
   struct boundary_tag* tag;
+  spin_lock_ctx_t ctxliba;
 
   if (ptr == NULL)
     return;
 
-  liballoc_lock ();
+  liballoc_lock (&ctxliba);
 
   tag = (struct boundary_tag*)((uintptr_t)ptr - sizeof (struct boundary_tag));
 
   if (tag->magic != LIBALLOC_MAGIC) {
-    liballoc_unlock (); // release the lock
+    liballoc_unlock (&ctxliba); // release the lock
     return;
   }
 
@@ -354,7 +356,7 @@ void free (void* ptr) {
 
       liballoc_free (tag, pages);
 
-      liballoc_unlock ();
+      liballoc_unlock (&ctxliba);
       return;
     }
 
@@ -365,7 +367,7 @@ void free (void* ptr) {
 
   insert_tag (tag, index);
 
-  liballoc_unlock ();
+  liballoc_unlock (&ctxliba);
 }
 
 void* calloc (size_t nobj, size_t size) {
@@ -385,6 +387,7 @@ void* realloc (void* p, size_t size) {
   void* ptr;
   struct boundary_tag* tag;
   int real_size;
+  spin_lock_ctx_t ctxliba;
 
   if (size == 0) {
     free (p);
@@ -394,11 +397,11 @@ void* realloc (void* p, size_t size) {
     return malloc (size);
 
   if (&liballoc_lock != NULL)
-    liballoc_lock (); // lockit
+    liballoc_lock (&ctxliba); // lockit
   tag = (struct boundary_tag*)((uintptr_t)p - sizeof (struct boundary_tag));
   real_size = tag->size;
   if (&liballoc_unlock != NULL)
-    liballoc_unlock ();
+    liballoc_unlock (&ctxliba);
 
   if ((size_t)real_size > size)
     real_size = size;

kernel/mm/liballoc.h

@@ -47,7 +47,7 @@ struct boundary_tag {
  * \return 0 if the lock was acquired successfully. Anything else is
  * failure.
  */
-extern int liballoc_lock ();
+extern int liballoc_lock (void* ctx);
 
 /** This function unlocks what was previously locked by the liballoc_lock
  * function.  If it disabled interrupts, it enables interrupts. If it
@@ -55,7 +55,7 @@ extern int liballoc_lock ();
  *
  * \return 0 if the lock was successfully released.
  */
-extern int liballoc_unlock ();
+extern int liballoc_unlock (void* ctx);
 
 /** This is the hook into the local system which allocates pages. It
  * accepts an integer parameter which is the number of pages

kernel/mm/pmm.c

@@ -38,8 +38,8 @@ void pmm_init (void) {
       struct pmm_region* pmm_region = &pmm.regions[region];
 
       /*
-       * We need to calculate sizes for the pmm region and the bitmap. The bitmap MUSTN'T include it's
+       * We need to calculate sizes for the pmm region and the bitmap. The bitmap MUSTN'T include
-       * own region within the bit range.
+       * it's own region within the bit range.
        * */
 
       size_t size = align_down (entry->length, PAGE_SIZE);
@@ -100,6 +100,8 @@ static size_t pmm_find_free_space (struct pmm_region* pmm_region, size_t nblks)
 }
 
 physaddr_t pmm_alloc (size_t nblks) {
+  spin_lock_ctx_t ctxpmmr;
+
   for (size_t region = 0; region < PMM_REGIONS_MAX; region++) {
     struct pmm_region* pmm_region = &pmm.regions[region];
 
@@ -107,7 +109,7 @@ physaddr_t pmm_alloc (size_t nblks) {
     if (!(pmm_region->flags & PMM_REGION_ACTIVE))
       continue;
 
-    spin_lock (&pmm_region->lock);
+    spin_lock (&pmm_region->lock, &ctxpmmr);
 
     /* Find starting bit of the free bit range */
     size_t bit = pmm_find_free_space (pmm_region, nblks);
@@ -116,18 +118,19 @@ physaddr_t pmm_alloc (size_t nblks) {
     if (bit != (size_t)-1) {
       /* Mark it */
       bm_set_region (&pmm_region->bm, bit, nblks);
-      spin_unlock (&pmm_region->lock);
+      spin_unlock (&pmm_region->lock, &ctxpmmr);
 
       return pmm_region->membase + bit * PAGE_SIZE;
     }
 
-    spin_unlock (&pmm_region->lock);
+    spin_unlock (&pmm_region->lock, &ctxpmmr);
   }
 
   return PMM_ALLOC_ERR;
 }
 
 void pmm_free (physaddr_t p_addr, size_t nblks) {
+  spin_lock_ctx_t ctxpmmr;
   /* Round down to nearest page boundary */
   physaddr_t aligned_p_addr = align_down (p_addr, PAGE_SIZE);
 
@@ -145,11 +148,11 @@ void pmm_free (physaddr_t p_addr, size_t nblks) {
 
       size_t bit = div_align_up (addr, PAGE_SIZE);
 
-      spin_lock (&pmm_region->lock);
+      spin_lock (&pmm_region->lock, &ctxpmmr);
 
       bm_clear_region (&pmm_region->bm, bit, nblks);
 
-      spin_unlock (&pmm_region->lock);
+      spin_unlock (&pmm_region->lock, &ctxpmmr);
 
       break;
     }

kernel/proc/locks.txt

@@ -0,0 +1,10 @@
+Lock hierarchy for process scheduling:
+
+1. proc_tree_lock
+2. cpu->lock
+3. procgroup->lock
+4. proc->lock
+5. sq->lock
+
+1. procgroup_tree_lock
+2. procgroup->lock

kernel/proc/mutex.c

@@ -0,0 +1,130 @@
+#include <libk/assert.h>
+#include <libk/rbtree.h>
+#include <libk/std.h>
+#include <libk/string.h>
+#include <mm/liballoc.h>
+#include <proc/mutex.h>
+#include <proc/proc.h>
+#include <proc/suspension_q.h>
+#include <sync/spin_lock.h>
+#include <sys/debug.h>
+#include <sys/smp.h>
+#include <sys/spin_lock.h>
+
+void proc_mutexes_cleanup (struct proc* proc) {
+  spin_lock_ctx_t ctxpg, ctxrs;
+
+  spin_lock (&proc->procgroup->lock, &ctxpg);
+
+  struct rb_node_link* rnode;
+  rbtree_first (&proc->procgroup->resource_tree, rnode);
+
+  while (rnode) {
+    struct rb_node_link* next;
+    rbtree_next (rnode, next);
+
+    struct proc_resource* resource = rbtree_entry (rnode, struct proc_resource, resource_tree_link);
+
+    rnode = next;
+
+    spin_lock (&resource->lock, &ctxrs);
+
+    if (resource->type != PR_MUTEX) {
+      spin_unlock (&resource->lock, &ctxrs);
+      continue;
+    }
+
+    if (resource->u.mutex.owner == proc && resource->u.mutex.locked) {
+      spin_unlock (&resource->lock, &ctxrs);
+
+      proc_mutex_unlock (proc, &resource->u.mutex);
+    }
+  }
+
+  spin_unlock (&proc->procgroup->lock, &ctxpg);
+}
+
+bool proc_cleanup_resource_mutex (struct proc_resource* resource) {
+  struct proc_mutex* mutex = &resource->u.mutex;
+  spin_lock_ctx_t ctxmt, ctxsq;
+
+  spin_lock (&mutex->resource->lock, &ctxmt);
+  spin_lock (&mutex->suspension_q.lock, &ctxsq);
+
+  bool reschedule = PROC_NO_RESCHEDULE;
+
+  while (mutex->suspension_q.proc_list != NULL) {
+    struct list_node_link* node = mutex->suspension_q.proc_list;
+    struct proc_sq_entry* sq_entry = list_entry (node, struct proc_sq_entry, sq_link);
+    struct proc* suspended_proc = sq_entry->proc;
+
+    /* we will relock during resume */
+    spin_unlock (&mutex->suspension_q.lock, &ctxsq);
+    spin_unlock (&mutex->resource->lock, &ctxmt);
+
+    reschedule = reschedule || proc_sq_resume (suspended_proc, sq_entry);
+
+    /* reacquire */
+    spin_lock (&mutex->resource->lock, &ctxmt);
+    spin_lock (&mutex->suspension_q.lock, &ctxsq);
+  }
+
+  mutex->locked = false;
+  mutex->owner = NULL;
+
+  spin_unlock (&mutex->suspension_q.lock, &ctxsq);
+  spin_unlock (&mutex->resource->lock, &ctxmt);
+
+  return reschedule;
+}
+
+bool proc_mutex_lock (struct proc* proc, struct proc_mutex* mutex) {
+  spin_lock_ctx_t ctxmt;
+
+  spin_lock (&mutex->resource->lock, &ctxmt);
+
+  if (!mutex->locked || mutex->owner == proc) {
+    mutex->locked = true;
+    mutex->owner = proc;
+    spin_unlock (&mutex->resource->lock, &ctxmt);
+    return PROC_NO_RESCHEDULE;
+  }
+
+  return proc_sq_suspend (proc, &mutex->suspension_q, &mutex->resource->lock, &ctxmt);
+}
+
+bool proc_mutex_unlock (struct proc* proc, struct proc_mutex* mutex) {
+  spin_lock_ctx_t ctxmt, ctxsq;
+
+  spin_lock (&mutex->resource->lock, &ctxmt);
+
+  if (mutex->owner != proc) {
+    spin_unlock (&mutex->resource->lock, &ctxmt);
+    return PROC_NO_RESCHEDULE;
+  }
+
+  spin_lock (&mutex->suspension_q.lock, &ctxsq);
+
+  struct list_node_link* node = mutex->suspension_q.proc_list;
+
+  if (node) {
+    struct proc_sq_entry* sq_entry = list_entry (node, struct proc_sq_entry, sq_link);
+    struct proc* resumed_proc = sq_entry->proc;
+
+    mutex->owner = resumed_proc;
+    mutex->locked = true;
+
+    spin_unlock (&mutex->suspension_q.lock, &ctxsq);
+    spin_unlock (&mutex->resource->lock, &ctxmt);
+
+    return proc_sq_resume (resumed_proc, sq_entry);
+  }
+
+  mutex->locked = false;
+  mutex->owner = NULL;
+
+  spin_unlock (&mutex->suspension_q.lock, &ctxsq);
+  spin_unlock (&mutex->resource->lock, &ctxmt);
+
+  return PROC_NEED_RESCHEDULE;
+}

kernel/proc/mutex.h

@@ -0,0 +1,23 @@
+#ifndef _KERNEL_PROC_MUTEX_H
+#define _KERNEL_PROC_MUTEX_H
+
+#include <libk/std.h>
+#include <proc/suspension_q.h>
+
+struct proc;
+struct proc_resource;
+
+struct proc_mutex {
+  struct proc_resource* resource;
+
+  bool locked;
+  struct proc_suspension_q suspension_q;
+  struct proc* owner;
+};
+
+bool proc_cleanup_resource_mutex (struct proc_resource* resource);
+bool proc_mutex_lock (struct proc* proc, struct proc_mutex* mutex);
+bool proc_mutex_unlock (struct proc* proc, struct proc_mutex* mutex);
+void proc_mutexes_cleanup (struct proc* proc);
+
+#endif // _KERNEL_PROC_MUTEX_H

kernel/proc/proc.c

@@ -3,32 +3,34 @@
 #include <irq/irq.h>
 #include <libk/align.h>
 #include <libk/list.h>
+#include <libk/rbtree.h>
 #include <libk/std.h>
 #include <libk/string.h>
 #include <limine/requests.h>
 #include <mm/liballoc.h>
 #include <mm/pmm.h>
 #include <proc/proc.h>
+#include <proc/procgroup.h>
+#include <proc/resource.h>
 #include <rd/rd.h>
 #include <sync/spin_lock.h>
 #include <sys/debug.h>
 #include <sys/mm.h>
+#include <sys/proc.h>
 #include <sys/sched.h>
 #include <sys/smp.h>
+#include <sys/spin.h>
 
 #if defined(__x86_64__)
 #include <amd64/intr_defs.h>
 #endif
 
-struct elf_aux {
+#define SCHED_REAP_FREQ 10
-  uint64_t entry;
-  uint64_t phdr;
-  uint64_t phent;
-  uint64_t phnum;
-};
 
-static struct procw* procs;
+static struct rb_node_link* proc_tree = NULL;
-static spin_lock_t procs_lock = SPIN_LOCK_INIT;
+static spin_lock_t proc_tree_lock = SPIN_LOCK_INIT;
+
+static atomic_int sched_cycles = 0;
 
 static bool proc_check_elf (uint8_t* elf) {
   if (!((elf[0] == 0x7F) && (elf[1] == 'E') && (elf[2] == 'L') && (elf[3] == 'F')))
@@ -36,28 +38,7 @@ static bool proc_check_elf (uint8_t* elf) {
   return true;
 }
 
-void proc_map (struct proc* proc, uintptr_t start_paddr, uintptr_t start_vaddr, size_t pages,
+struct elf_aux proc_load_segments (struct proc* proc, uint8_t* elf) {
-               uint32_t flags) {
-  struct proc_mapping* mapping = malloc (sizeof (*mapping));
-  mapping->paddr = start_paddr;
-  mapping->vaddr = start_vaddr;
-  mapping->size = pages * PAGE_SIZE;
-
-  flags &= ~MM_PD_LOCK; /* clear LOCK flag if present, because we lock manualy */
-
-  spin_lock (&proc->pd.lock);
-
-  linklist_append (struct proc_mapping*, proc->mappings, mapping);
-
-  for (uintptr_t vpage = start_vaddr, ppage = start_paddr; vpage < start_vaddr + pages * PAGE_SIZE;
-       vpage += PAGE_SIZE, ppage += PAGE_SIZE) {
-    mm_map_page (&proc->pd, ppage, vpage, flags);
-  }
-
-  spin_unlock (&proc->pd.lock);
-}
-
-static struct elf_aux proc_load_segments (struct proc* proc, uint8_t* elf) {
   struct elf_aux aux;
 
   Elf64_Ehdr* ehdr = (Elf64_Ehdr*)elf;
@@ -81,19 +62,37 @@ static struct elf_aux proc_load_segments (struct proc* proc, uint8_t* elf) {
 
       size_t blks = div_align_up (phdr->p_memsz + off, PAGE_SIZE);
 
-      uintptr_t p_addr = pmm_alloc (blks);
-      if (p_addr == PMM_ALLOC_ERR)
-        DEBUG ("pmm oom error while loading ELF segments! (tried to alloc %zu blks)\n", blks);
-
-      memset ((void*)((uintptr_t)hhdm->offset + p_addr), 0, blks * PAGE_SIZE);
-      memcpy ((void*)((uintptr_t)hhdm->offset + p_addr + off),
-              (void*)((uintptr_t)elf + phdr->p_offset), phdr->p_filesz);
-
       uint32_t pg_flags = MM_PG_USER | MM_PG_PRESENT;
       if (phdr->p_flags & PF_W)
         pg_flags |= MM_PG_RW;
 
-      proc_map (proc, p_addr, v_addr, blks, pg_flags);
+      uintptr_t p_addr;
+      procgroup_map (proc->procgroup, v_addr, blks, pg_flags, &p_addr);
+
+      memset ((void*)((uintptr_t)hhdm->offset + p_addr), 0, blks * PAGE_SIZE);
+      memcpy ((void*)((uintptr_t)hhdm->offset + p_addr + off),
+              (void*)((uintptr_t)elf + phdr->p_offset), phdr->p_filesz);
+    } break;
+    case PT_TLS: {
+#if defined(__x86_64__)
+      if (phdr->p_memsz > 0) {
+        size_t tls_align = phdr->p_align ? phdr->p_align : sizeof (uintptr_t);
+        size_t tls_size = align_up (phdr->p_memsz, tls_align);
+        size_t tls_total_needed = tls_size + sizeof (uintptr_t);
+        size_t blks = div_align_up (tls_total_needed, PAGE_SIZE);
+        proc->procgroup->tls.tls_tmpl_pages = blks;
+        proc->procgroup->tls.tls_tmpl_size = tls_size;
+        proc->procgroup->tls.tls_tmpl_total_size = tls_total_needed;
+
+        proc->procgroup->tls.tls_tmpl = malloc (blks * PAGE_SIZE);
+        memset (proc->procgroup->tls.tls_tmpl, 0, blks * PAGE_SIZE);
+
+        memcpy (proc->procgroup->tls.tls_tmpl, (void*)((uintptr_t)elf + phdr->p_offset),
+                phdr->p_filesz);
+
+        proc_init_tls (proc);
+      }
+#endif
     } break;
     }
   }
@@ -101,145 +100,184 @@ static struct elf_aux proc_load_segments (struct proc* proc, uint8_t* elf) {
   return aux;
 }
 
-static struct proc* proc_spawn_rd (char* name) {
+struct proc* proc_spawn_rd (char* name) {
   struct rd_file* rd_file = rd_get_file (name);
 
   bool ok = proc_check_elf (rd_file->content);
-  DEBUG ("ELF magic %s\n", (ok ? "OK" : "BAD"));
 
   if (!ok)
     return NULL;
 
-  struct proc* proc = malloc (sizeof (*proc));
+  return proc_from_elf (rd_file->content);
-  if (proc == NULL)
-    return NULL;
-
-  memset (proc, 0, sizeof (*proc));
-
-#if defined(__x86_64__)
-  proc->pd.lock = SPIN_LOCK_INIT;
-  proc->pd.cr3_paddr = mm_alloc_user_pd_phys ();
-  if (proc->pd.cr3_paddr == 0) {
-    free (proc);
-    return NULL;
 }
 
-  proc->pdata.syscall_stack = pmm_alloc (KSTACK_SIZE / PAGE_SIZE);
+struct proc* proc_find_pid (int pid) {
-  if (proc->pdata.syscall_stack == PMM_ALLOC_ERR) {
+  spin_lock_ctx_t ctxprtr;
-    free (proc);
+  struct proc* proc = NULL;
-    return NULL;
-  }
 
-  proc->pdata.user_stack = pmm_alloc (USTACK_SIZE / PAGE_SIZE);
+  spin_lock (&proc_tree_lock, &ctxprtr);
-  if (proc->pdata.user_stack == PMM_ALLOC_ERR) {
+  rbtree_find (struct proc, &proc_tree, pid, proc, proc_tree_link, pid);
-    free (proc);
+  spin_unlock (&proc_tree_lock, &ctxprtr);
-    pmm_free (proc->pdata.syscall_stack, USTACK_SIZE / PAGE_SIZE);
-    return NULL;
-  }
-
-  uintptr_t user_stack = proc->pdata.user_stack;
-
-  proc->pdata.syscall_stack += KSTACK_SIZE;
-  proc->pdata.user_stack += USTACK_SIZE;
-
-  proc_map (proc, user_stack, PROC_USTACK_TOP - USTACK_SIZE, USTACK_SIZE / PAGE_SIZE,
-            MM_PG_USER | MM_PG_PRESENT | MM_PG_RW);
-
-  struct elf_aux aux = proc_load_segments (proc, rd_file->content);
-
-  proc->pdata.regs.ss = 0x20 | 0x03;
-  proc->pdata.regs.rsp = (uint64_t)PROC_USTACK_TOP;
-  proc->pdata.regs.rflags = 0x202;
-  proc->pdata.regs.cs = 0x18 | 0x03;
-  proc->pdata.regs.rip = aux.entry;
-  proc->lock = SPIN_LOCK_INIT;
-#endif
 
   return proc;
 }
 
-static void proc_register (struct proc* proc) {
+void proc_register (struct proc* proc, struct cpu* cpu1) {
-  /* make available globally. */
+  spin_lock_ctx_t ctxcpu, ctxprtr;
-  struct procw* procw = malloc (sizeof (*procw));
-  if (procw == NULL)
-    return;
-  procw->proc = proc;
-  proc->procw = procw;
 
-  spin_lock (&procs_lock);
+  proc->cpu = cpu1 != NULL ? cpu1 : cpu_find_lightest ();
 
-  spin_lock (&thiscpu->lock);
+  struct cpu* cpu = proc->cpu;
 
-  linklist_append (struct procw*, procs, procw);
+  spin_lock (&proc_tree_lock, &ctxprtr);
-  linklist_append (struct proc*, thiscpu->proc_run_q, proc);
+  spin_lock (&cpu->lock, &ctxcpu);
 
-  if (thiscpu->proc_current == NULL)
+  rbtree_insert (struct proc, &proc_tree, &proc->proc_tree_link, proc_tree_link, pid);
-    thiscpu->proc_current = proc;
 
-  spin_unlock (&thiscpu->lock);
+  atomic_fetch_add (&cpu->proc_run_q_count, 1);
+  list_append (cpu->proc_run_q, &proc->cpu_run_q_link);
+  if (cpu->proc_current == NULL)
+    cpu->proc_current = proc;
 
-  spin_unlock (&procs_lock);
+  spin_unlock (&proc_tree_lock, &ctxprtr);
+  spin_unlock (&cpu->lock, &ctxcpu);
+}
+
+/* caller holds cpu->lock */
+static struct proc* proc_find_sched (struct cpu* cpu) {
+  if (!cpu->proc_run_q)
+    return NULL;
+
+  struct list_node_link *current, *start;
+
+  if (cpu->proc_current)
+    current = cpu->proc_current->cpu_run_q_link.next;
+  else
+    current = cpu->proc_run_q;
+
+  if (!current)
+    current = cpu->proc_run_q;
+
+  start = current;
+
+  do {
+    struct proc* proc = list_entry (current, struct proc, cpu_run_q_link);
+
+    if (atomic_load (&proc->state) == PROC_READY)
+      return proc;
+
+    current = current->next ? current->next : cpu->proc_run_q;
+  } while (current != start);
+
+  return NULL;
+}
+
+static void proc_reap (void) {
+  struct proc* proc = NULL;
+  struct list_node_link* reap_list = NULL;
+  spin_lock_ctx_t ctxprtr;
+  spin_lock_ctx_t ctxpr;
+
+  spin_lock (&proc_tree_lock, &ctxprtr);
+
+  struct rb_node_link* node;
+  rbtree_first (&proc_tree, node);
+
+  while (node) {
+    struct rb_node_link* next;
+    rbtree_next (node, next);
+    proc = rbtree_entry (node, struct proc, proc_tree_link);
+
+    if (atomic_load (&proc->state) == PROC_DEAD) {
+      spin_lock (&proc->lock, &ctxpr);
+      rbtree_delete (&proc_tree, &proc->proc_tree_link);
+      list_append (reap_list, &proc->reap_link);
+      spin_unlock (&proc->lock, &ctxpr);
+    }
+
+    node = next;
+  }
+
+  spin_unlock (&proc_tree_lock, &ctxprtr);
+
+  struct list_node_link *reap_link, *reap_link_tmp;
+  list_foreach (reap_list, reap_link, reap_link_tmp) {
+    proc = list_entry (reap_link, struct proc, reap_link);
+
+    list_remove (reap_list, &proc->reap_link);
+    DEBUG ("cleanup PID %d\n", proc->pid);
+    proc_cleanup (proc);
+  }
 }
 
 void proc_sched (void) {
-  spin_lock (&thiscpu->lock);
+  spin_lock_ctx_t ctxcpu;
 
-  if (thiscpu->proc_run_q == NULL || thiscpu->proc_current == NULL) {
+  int s_cycles = atomic_fetch_add (&sched_cycles, 1);
-    goto done;
+
+  if (s_cycles % SCHED_REAP_FREQ == 0)
+    proc_reap ();
+
+  struct proc* next = NULL;
+  struct cpu* cpu = thiscpu;
+
+  spin_lock (&cpu->lock, &ctxcpu);
+
+  next = proc_find_sched (cpu);
+
+  if (next) {
+    cpu->proc_current = next;
+
+    do_sched (next, &cpu->lock, &ctxcpu);
+  } else {
+    cpu->proc_current = NULL;
+    spin_unlock (&cpu->lock, &ctxcpu);
+
+    spin ();
   }
-
-  thiscpu->proc_current = thiscpu->proc_current->next;
-
-  if (thiscpu->proc_current == NULL) {
-    thiscpu->proc_current = thiscpu->proc_run_q;
-  }
-
-done:
-  spin_unlock (&thiscpu->lock);
-
-  if (thiscpu->proc_current != NULL) {
-    do_sched (&thiscpu->proc_current->pdata.regs, &thiscpu->proc_current->pd);
-  }
-
-#if defined(__x86_64__)
-  extern void amd64_spin (void);
-
-  amd64_spin ();
-#endif
 }
 
 void proc_kill (struct proc* proc) {
-  spin_lock (&procs_lock);
+  spin_lock_ctx_t ctxpr, ctxcpu;
+  struct cpu* cpu = proc->cpu;
 
-  spin_lock (&thiscpu->lock);
+  spin_lock (&proc->lock, &ctxpr);
+  atomic_store (&proc->state, PROC_DEAD);
+  proc->cpu = NULL;
+  spin_unlock (&proc->lock, &ctxpr);
 
-  linklist_remove (struct procw*, procs, proc->procw);
+  spin_lock (&cpu->lock, &ctxcpu);
-  linklist_remove (struct proc*, thiscpu->proc_run_q, proc);
 
-  if (thiscpu->proc_current == proc)
+  list_remove (cpu->proc_run_q, &proc->cpu_run_q_link);
-    thiscpu->proc_current = NULL;
+  atomic_fetch_sub (&cpu->proc_run_q_count, 1);
+  if (cpu->proc_current == proc)
+    cpu->proc_current = NULL;
 
-  spin_unlock (&thiscpu->lock);
+  spin_unlock (&cpu->lock, &ctxcpu);
 
-  spin_unlock (&procs_lock);
+  DEBUG ("killed PID %d\n", proc->pid);
 
-  /* clean up */
+  cpu_request_sched (cpu);
-  free (proc->procw);
-  free (proc);
 }
 
 static void proc_irq_sched (void* arg, void* regs) {
-  (void)arg, (void)regs;
+  (void)arg;
   proc_sched ();
 }
 
 void proc_init (void) {
-  struct proc* init = proc_spawn_rd ("init.exe");
-  proc_register (init);
-
 #if defined(__x86_64__)
-  irq_attach (&proc_irq_sched, NULL, SCHED_PREEMPT_TIMER, 0);
+  irq_attach (&proc_irq_sched, NULL, SCHED_PREEMPT_TIMER);
+  irq_attach (&proc_irq_sched, NULL, CPU_REQUEST_SCHED);
 #endif
 
-  do_sched (&init->pdata.regs, &init->pd);
+  struct proc* spin_proc = proc_spawn_rd ("spin.exe");
+  proc_register (spin_proc, thiscpu);
+
+  struct proc* init = proc_spawn_rd ("init.exe");
+  proc_register (init, NULL);
+
+  spin_lock_ctx_t ctxcpu;
+  spin_lock (&spin_proc->cpu->lock, &ctxcpu);
+  do_sched (spin_proc, &spin_proc->cpu->lock, &ctxcpu);
 }

kernel/proc/proc.h

@@ -2,7 +2,13 @@
 #define _KERNEL_PROC_PROC_H
 
 #include <aux/compiler.h>
+#include <aux/elf.h>
+#include <libk/list.h>
+#include <libk/rbtree.h>
 #include <libk/std.h>
+#include <proc/procgroup.h>
+#include <proc/resource.h>
+#include <proc/suspension_q.h>
 #include <sync/spin_lock.h>
 #include <sys/mm.h>
 
@@ -11,39 +17,41 @@
 #include <amd64/proc.h> /* USTACK_SIZE */
 #endif
 
+#define PROC_NEED_RESCHEDULE true
+#define PROC_NO_RESCHEDULE   false
+
+/* process states */
+#define PROC_READY     0
+#define PROC_DEAD      1
+#define PROC_SUSPENDED 2
+
+/* process flags */
+#define PROC_USTK_PREALLOC (1 << 0)
+
 struct cpu;
 
-struct proc_mapping {
-  struct proc_mapping* next;
-  uintptr_t paddr;
-  uintptr_t vaddr;
-  size_t size;
-} PACKED;
-
-struct procw;
-
 struct proc {
-  struct proc* next;
+  int pid;
-  struct proc_mapping* mappings; /* pd.lock implicitly protects this field */
+  struct rb_node_link proc_tree_link;
+  struct rb_node_link procgroup_memb_tree_link;
+  struct list_node_link cpu_run_q_link;
+  struct list_node_link reap_link;
+  struct list_node_link* sq_entries;
+  struct procgroup* procgroup;
   struct proc_platformdata pdata;
-  struct pd pd;
+  uint32_t flags;
   spin_lock_t lock;
   struct cpu* cpu;
-  struct procw* procw; /* link to it's global struct */
+  atomic_int state;
-};
+  uintptr_t uvaddr_argument;
-
-/*
- * struct proc is a member of a CPU's proc_run_q.
- * struct procw is a process wrapper that is a member of
- * a global process list.
- */
-struct procw {
-  struct procw* next;
-  struct proc* proc;
 };
 
 void proc_sched (void);
 void proc_kill (struct proc* proc);
+struct elf_aux proc_load_segments (struct proc* proc, uint8_t* elf);
+void proc_register (struct proc* proc, struct cpu* cpu);
+struct proc* proc_find_pid (int pid);
+struct proc* proc_spawn_rd (char* name);
 void proc_init (void);
 
 #endif // _KERNEL_PROC_PROC_H

kernel/proc/procgroup.c

@@ -0,0 +1,218 @@
+#include <libk/rbtree.h>
+#include <libk/std.h>
+#include <mm/liballoc.h>
+#include <mm/pmm.h>
+#include <proc/proc.h>
+#include <proc/procgroup.h>
+#include <sync/spin_lock.h>
+#include <sys/debug.h>
+#include <sys/mm.h>
+
+static struct rb_node_link* procgroup_tree = NULL;
+static spin_lock_t procgroup_tree_lock = SPIN_LOCK_INIT;
+static atomic_int pgids = 0;
+
+uintptr_t procgroup_map (struct procgroup* procgroup, uintptr_t vaddr, size_t pages, uint32_t flags,
+                         uintptr_t* out_paddr) {
+  spin_lock_ctx_t ctxpg;
+
+  spin_lock (&procgroup->lock, &ctxpg);
+
+  vaddr = (vaddr == 0) ? procgroup->map_base : vaddr;
+
+  struct proc_mapping* mapping = malloc (sizeof (*mapping));
+
+  if (mapping == NULL) {
+    spin_unlock (&procgroup->lock, &ctxpg);
+    return 0;
+  }
+
+  uintptr_t paddr = pmm_alloc (pages);
+
+  if (paddr == PMM_ALLOC_ERR) {
+    free (mapping);
+    spin_unlock (&procgroup->lock, &ctxpg);
+    return 0;
+  }
+
+  if (out_paddr != NULL)
+    *out_paddr = paddr;
+
+  mapping->paddr = paddr;
+  mapping->vaddr = vaddr;
+  mapping->size = pages * PAGE_SIZE;
+
+  procgroup->map_base += pages * PAGE_SIZE;
+
+  list_append (procgroup->mappings, &mapping->proc_mappings_link);
+
+  for (uintptr_t vpage = vaddr, ppage = paddr; vpage < vaddr + pages * PAGE_SIZE;
+       vpage += PAGE_SIZE, ppage += PAGE_SIZE) {
+    mm_map_page (&procgroup->pd, ppage, vpage, flags);
+  }
+
+  spin_unlock (&procgroup->lock, &ctxpg);
+
+  return vaddr;
+}
+
+bool procgroup_unmap (struct procgroup* procgroup, uintptr_t start_vaddr, size_t pages) {
+  size_t unmap_size = pages * PAGE_SIZE;
+  uintptr_t end_vaddr = start_vaddr + unmap_size;
+
+  struct list_node_link *mapping_link, *mapping_link_tmp;
+
+  bool used_tail_mapping = false;
+  spin_lock_ctx_t ctxpg;
+
+  struct proc_mapping* tail_mapping = malloc (sizeof (*tail_mapping));
+  if (tail_mapping == NULL)
+    return false;
+
+  spin_lock (&procgroup->lock, &ctxpg);
+
+  list_foreach (procgroup->mappings, mapping_link, mapping_link_tmp) {
+    struct proc_mapping* mapping =
+        list_entry (mapping_link, struct proc_mapping, proc_mappings_link);
+
+    uintptr_t m_start = mapping->vaddr;
+    uintptr_t m_end = mapping->vaddr + mapping->size;
+
+    /* check overlap */
+    if ((start_vaddr < m_end) && (end_vaddr > mapping->vaddr)) {
+      uintptr_t free_vstart = (start_vaddr > m_start) ? start_vaddr : m_start;
+      uintptr_t free_vend = (end_vaddr < m_end) ? end_vaddr : m_end;
+      size_t free_size = free_vend - free_vstart;
+
+      uintptr_t ppage_to_free = mapping->paddr + (free_vstart - m_start);
+      pmm_free (ppage_to_free, free_size / PAGE_SIZE);
+
+      /* split in the middle */
+      if ((start_vaddr > m_start) && (end_vaddr < m_end)) {
+        tail_mapping->vaddr = end_vaddr;
+        tail_mapping->paddr = mapping->paddr + (end_vaddr - m_start);
+        tail_mapping->size = m_end - end_vaddr;
+
+        mapping->size = start_vaddr - m_start;
+
+        list_insert_after (procgroup->mappings, &mapping->proc_mappings_link,
+                           &tail_mapping->proc_mappings_link);
+
+        used_tail_mapping = true;
+
+        break;
+      } else if ((start_vaddr <= m_start) && (end_vaddr < m_end)) { /* shrink left */
+        size_t diff = end_vaddr - m_start;
+        mapping->vaddr += diff;
+        mapping->paddr += diff;
+        mapping->size -= diff;
+      } else if ((start_vaddr > m_start) && (end_vaddr >= m_end)) { /* shrink right */
+        mapping->size = start_vaddr - m_start;
+      } else { /* full overlap */
+        list_remove (procgroup->mappings, &mapping->proc_mappings_link);
+        free (mapping);
+      }
+    }
+  }
+
+  if (!used_tail_mapping)
+    free (tail_mapping);
+
+  for (uintptr_t vpage = start_vaddr; vpage < end_vaddr; vpage += PAGE_SIZE) {
+    mm_unmap_page (&procgroup->pd, vpage);
+  }
+
+  spin_unlock (&procgroup->lock, &ctxpg);
+
+  return true;
+}
+
+struct procgroup* procgroup_create (void) {
+  spin_lock_ctx_t ctxpgtr;
+
+  struct procgroup* procgroup = malloc (sizeof (*procgroup));
+  if (procgroup == NULL) {
+    return NULL;
+  }
+
+  procgroup->refs = 0;
+  procgroup->memb_proc_tree = NULL;
+  procgroup->lock = SPIN_LOCK_INIT;
+  procgroup->pgid = atomic_fetch_add (&pgids, 1);
+  procgroup->pd.cr3_paddr = mm_alloc_user_pd_phys ();
+  procgroup->map_base = PROC_MAP_BASE;
+
+  spin_lock (&procgroup_tree_lock, &ctxpgtr);
+  rbtree_insert (struct procgroup, &procgroup_tree, &procgroup->procgroup_tree_link,
+                 procgroup_tree_link, pgid);
+  spin_unlock (&procgroup_tree_lock, &ctxpgtr);
+
+  return procgroup;
+}
+
+void procgroup_attach (struct procgroup* procgroup, struct proc* proc) {
+  spin_lock_ctx_t ctxpg, ctxpr;
+
+  spin_lock (&procgroup->lock, &ctxpg);
+  spin_lock (&proc->lock, &ctxpr);
+
+  rbtree_insert (struct proc, &procgroup->memb_proc_tree, &proc->procgroup_memb_tree_link,
+                 procgroup_memb_tree_link, pid);
+  atomic_fetch_add (&procgroup->refs, 1);
+
+  spin_unlock (&proc->lock, &ctxpr);
+  spin_unlock (&procgroup->lock, &ctxpg);
+}
+
+void procgroup_detach (struct procgroup* procgroup, struct proc* proc) {
+  spin_lock_ctx_t ctxpg, ctxpr, ctxpgtr;
+
+  spin_lock (&procgroup->lock, &ctxpg);
+  spin_lock (&proc->lock, &ctxpr);
+
+  rbtree_delete (&procgroup->memb_proc_tree, &proc->procgroup_memb_tree_link);
+  int refs = atomic_fetch_sub (&procgroup->refs, 1);
+
+  spin_unlock (&proc->lock, &ctxpr);
+  spin_unlock (&procgroup->lock, &ctxpg);
+
+  if (refs == 1) {
+    spin_lock (&procgroup_tree_lock, &ctxpgtr);
+    spin_lock (&procgroup->lock, &ctxpg);
+
+    rbtree_delete (&procgroup_tree, &procgroup->procgroup_tree_link);
+
+    spin_unlock (&procgroup->lock, &ctxpg);
+    spin_unlock (&procgroup_tree_lock, &ctxpgtr);
+
+    /* delete resources */
+    struct rb_node_link* rnode;
+    rbtree_first (&procgroup->resource_tree, rnode);
+    while (rnode) {
+      struct rb_node_link* next;
+      rbtree_next (rnode, next);
+
+      struct proc_resource* resource =
+          rbtree_entry (rnode, struct proc_resource, resource_tree_link);
+
+      rnode = next;
+
+      proc_delete_resource (resource);
+    }
+
+    struct list_node_link *mapping_link, *mapping_link_tmp;
+    list_foreach (procgroup->mappings, mapping_link, mapping_link_tmp) {
+      struct proc_mapping* mapping =
+          list_entry (mapping_link, struct proc_mapping, proc_mappings_link);
+
+      pmm_free (mapping->paddr, mapping->size / PAGE_SIZE);
+      free (mapping);
+    }
+
+    pmm_free (procgroup->pd.cr3_paddr, 1);
+
+    free (procgroup->tls.tls_tmpl);
+
+    free (procgroup);
+  }
+}

kernel/proc/procgroup.h

@@ -0,0 +1,43 @@
+#ifndef _KERNEL_PROC_PROCGROUP_H
+#define _KERNEL_PROC_PROCGROUP_H
+
+#include <libk/list.h>
+#include <libk/rbtree.h>
+#include <libk/std.h>
+#include <proc/resource.h>
+#include <sync/spin_lock.h>
+#include <sys/mm.h>
+#include <sys/procgroup.h>
+
+struct proc;
+
+struct proc_mapping {
+  struct list_node_link proc_mappings_link;
+
+  uintptr_t paddr;
+  uintptr_t vaddr;
+  size_t size;
+};
+
+struct procgroup {
+  int pgid;
+  struct rb_node_link procgroup_tree_link;
+  struct rb_node_link* memb_proc_tree;
+  spin_lock_t lock;
+  atomic_int refs;
+  struct rb_node_link* resource_tree;
+  atomic_int sys_rids;
+  struct pd pd;
+  struct list_node_link* mappings;
+  uintptr_t map_base;
+  struct procgroup_tls tls;
+};
+
+struct procgroup* procgroup_create (void);
+void procgroup_attach (struct procgroup* procgroup, struct proc* proc);
+void procgroup_detach (struct procgroup* procgroup, struct proc* proc);
+uintptr_t procgroup_map (struct procgroup* procgroup, uintptr_t vaddr, size_t pages, uint32_t flags,
+                         uintptr_t* out_paddr);
+bool procgroup_unmap (struct procgroup* procgroup, uintptr_t start_vaddr, size_t pages);
+
+#endif // _KERNEL_PROC_PROCGROUP_H

kernel/proc/resource.c

@@ -0,0 +1,59 @@
+#include <libk/assert.h>
+#include <libk/list.h>
+#include <libk/rbtree.h>
+#include <libk/std.h>
+#include <libk/string.h>
+#include <mm/liballoc.h>
+#include <mm/pmm.h>
+#include <proc/mutex.h>
+#include <proc/proc.h>
+#include <proc/procgroup.h>
+#include <proc/resource.h>
+#include <sync/spin_lock.h>
+#include <sys/debug.h>
+
+struct proc_resource* proc_find_resource (struct procgroup* procgroup, int rid) {
+  spin_lock_ctx_t ctxpg;
+  struct proc_resource* resource = NULL;
+
+  spin_lock (&procgroup->lock, &ctxpg);
+  rbtree_find (struct proc_resource, &procgroup->resource_tree, rid, resource, resource_tree_link,
+               rid);
+  spin_unlock (&procgroup->lock, &ctxpg);
+
+  return resource;
+}
+
+struct proc_resource* proc_create_resource_mutex (struct procgroup* procgroup, int rid) {
+  spin_lock_ctx_t ctxpg;
+  struct proc_resource* resource;
+
+  resource = proc_find_resource (procgroup, rid);
+  if (resource != NULL)
+    return resource;
+
+  resource = malloc (sizeof (*resource));
+  if (resource == NULL)
+    return NULL;
+
+  memset (resource, 0, sizeof (*resource));
+  resource->lock = SPIN_LOCK_INIT;
+  resource->ops.cleanup = &proc_cleanup_resource_mutex;
+  resource->u.mutex.resource = resource;
+  resource->rid = rid;
+  resource->type = PR_MUTEX;
+
+  spin_lock (&procgroup->lock, &ctxpg);
+  rbtree_insert (struct proc_resource, &procgroup->resource_tree, &resource->resource_tree_link,
+                 resource_tree_link, rid);
+  spin_unlock (&procgroup->lock, &ctxpg);
+
+  return resource;
+}
+
+bool proc_delete_resource (struct proc_resource* resource) {
+  bool reschedule = resource->ops.cleanup (resource);
+  free (resource);
+
+  return reschedule;
+}

kernel/proc/resource.h

@@ -0,0 +1,32 @@
+#ifndef _KERNEL_PROC_RESOURCE_H
+#define _KERNEL_PROC_RESOURCE_H
+
+#include <libk/list.h>
+#include <libk/rbtree.h>
+#include <libk/std.h>
+#include <proc/mutex.h>
+#include <sync/spin_lock.h>
+
+#define PR_MUTEX 1
+
+struct proc;
+struct procgroup;
+
+struct proc_resource {
+  int type;
+  int rid;
+  spin_lock_t lock;
+  struct rb_node_link resource_tree_link;
+  union {
+    struct proc_mutex mutex;
+  } u;
+  struct {
+    bool (*cleanup) (struct proc_resource* resource);
+  } ops;
+};
+
+struct proc_resource* proc_find_resource (struct procgroup* procgroup, int rid);
+struct proc_resource* proc_create_resource_mutex (struct procgroup* procgroup, int rid);
+bool proc_delete_resource (struct proc_resource* resource);
+
+#endif // _KERNEL_PROC_RESOURCE_H

kernel/proc/src.mk

@@ -1,3 +1,11 @@
-c += proc/proc.c
+c += proc/proc.c \
+		 proc/resource.c \
+		 proc/mutex.c \
+		 proc/procgroup.c \
+		 proc/suspension_q.c
 
-o += proc/proc.o
+o += proc/proc.o \
+		 proc/resource.o \
+		 proc/mutex.o \
+		 proc/procgroup.o \
+		 proc/suspension_q.o

kernel/proc/suspension_q.c

@@ -0,0 +1,111 @@
+#include <libk/list.h>
+#include <libk/std.h>
+#include <mm/liballoc.h>
+#include <proc/proc.h>
+#include <proc/resource.h>
+#include <proc/suspension_q.h>
+#include <sync/spin_lock.h>
+#include <sys/smp.h>
+#include <sys/spin_lock.h>
+
+bool proc_sq_suspend (struct proc* proc, struct proc_suspension_q* sq, spin_lock_t* resource_lock,
+                      spin_lock_ctx_t* ctxrl) {
+  spin_lock_ctx_t ctxpr, ctxcpu, ctxsq;
+  struct cpu* cpu = proc->cpu;
+
+  struct proc_sq_entry* sq_entry = malloc (sizeof (*sq_entry));
+  if (!sq_entry) {
+    spin_unlock (resource_lock, ctxrl);
+    return PROC_NO_RESCHEDULE;
+  }
+
+  sq_entry->proc = proc;
+  sq_entry->sq = sq;
+
+  spin_lock (&cpu->lock, &ctxcpu);
+  spin_lock (&proc->lock, &ctxpr);
+  spin_lock (&sq->lock, &ctxsq);
+
+  spin_unlock (resource_lock, ctxrl);
+
+  atomic_store (&proc->state, PROC_SUSPENDED);
+
+  /* append to sq's list */
+  list_append (sq->proc_list, &sq_entry->sq_link);
+
+  /* append to proc's list */
+  list_append (proc->sq_entries, &sq_entry->proc_link);
+
+  list_remove (cpu->proc_run_q, &proc->cpu_run_q_link);
+  atomic_fetch_sub (&cpu->proc_run_q_count, 1);
+
+  if (cpu->proc_current == proc)
+    cpu->proc_current = NULL;
+
+  proc->cpu = NULL;
+
+  spin_unlock (&sq->lock, &ctxsq);
+  spin_unlock (&proc->lock, &ctxpr);
+  spin_unlock (&cpu->lock, &ctxcpu);
+
+  return PROC_NEED_RESCHEDULE;
+}
+
+bool proc_sq_resume (struct proc* proc, struct proc_sq_entry* sq_entry) {
+  spin_lock_ctx_t ctxsq, ctxpr, ctxcpu;
+  struct cpu* cpu = cpu_find_lightest ();
+  struct proc_suspension_q* sq = sq_entry->sq;
+
+  spin_lock (&cpu->lock, &ctxcpu);
+  spin_lock (&proc->lock, &ctxpr);
+  spin_lock (&sq->lock, &ctxsq);
+
+  /* remove from sq's list */
+  list_remove (sq->proc_list, &sq_entry->sq_link);
+
+  /* remove from proc's list */
+  list_remove (proc->sq_entries, &sq_entry->proc_link);
+
+  proc->cpu = cpu;
+
+  if (proc->sq_entries == NULL)
+    atomic_store (&proc->state, PROC_READY);
+
+  list_append (cpu->proc_run_q, &proc->cpu_run_q_link);
+  atomic_fetch_add (&cpu->proc_run_q_count, 1);
+
+  spin_unlock (&sq->lock, &ctxsq);
+  spin_unlock (&proc->lock, &ctxpr);
+  spin_unlock (&cpu->lock, &ctxcpu);
+
+  free (sq_entry);
+
+  return PROC_NEED_RESCHEDULE;
+}
+
+void proc_sqs_cleanup (struct proc* proc) {
+  spin_lock_ctx_t ctxsq, ctxpr;
+
+  spin_lock (&proc->lock, &ctxpr);
+
+  /* clean suspension queue entries */
+  struct list_node_link *sq_link, *sq_link_tmp;
+  list_foreach (proc->sq_entries, sq_link, sq_link_tmp) {
+    struct proc_sq_entry* sq_entry = list_entry (sq_link, struct proc_sq_entry, proc_link);
+    struct proc_suspension_q* sq = sq_entry->sq;
+
+    spin_lock (&sq->lock, &ctxsq);
+
+    /* remove from sq's list */
+    list_remove (sq->proc_list, &sq_entry->sq_link);
+
+    /* remove from proc's list */
+    list_remove (proc->sq_entries, &sq_entry->proc_link);
+
+    spin_unlock (&sq->lock, &ctxsq);
+
+    free (sq_entry);
+  }
+
+  spin_unlock (&proc->lock, &ctxpr);
+}

kernel/proc/suspension_q.h

@@ -0,0 +1,26 @@
+#ifndef _KERNEL_PROC_SUSPENTION_Q_H
+#define _KERNEL_PROC_SUSPENTION_Q_H
+
+#include <libk/list.h>
+#include <sync/spin_lock.h>
+
+struct proc;
+
+struct proc_suspension_q {
+  struct list_node_link* proc_list;
+  spin_lock_t lock;
+};
+
+struct proc_sq_entry {
+  struct list_node_link sq_link;
+  struct list_node_link proc_link;
+  struct proc* proc;
+  struct proc_suspension_q* sq;
+};
+
+void proc_sqs_cleanup (struct proc* proc);
+bool proc_sq_suspend (struct proc* proc, struct proc_suspension_q* sq, spin_lock_t* resource_lock,
+                      spin_lock_ctx_t* ctxrl);
+bool proc_sq_resume (struct proc* proc, struct proc_sq_entry* sq_entry);
+
+#endif // _KERNEL_PROC_SUSPENTION_Q_H

kernel/src.mk

@@ -7,3 +7,4 @@ include uACPI/src.mk
 include irq/src.mk
 include rd/src.mk
 include proc/src.mk
+include syscall/src.mk

kernel/sync/spin_lock.c

@@ -3,15 +3,15 @@
 #include <sys/irq.h>
 #include <sys/spin_lock.h>
 
-void spin_lock (spin_lock_t* sl) {
+void spin_lock (spin_lock_t* sl, spin_lock_ctx_t* ctx) {
-  irq_save ();
+  irq_save (ctx);
 
   while (atomic_flag_test_and_set_explicit (sl, memory_order_acquire))
     spin_lock_relax ();
 }
 
-void spin_unlock (spin_lock_t* sl) {
+void spin_unlock (spin_lock_t* sl, spin_lock_ctx_t* ctx) {
   atomic_flag_clear_explicit (sl, memory_order_release);
 
-  irq_restore ();
+  irq_restore (ctx);
 }