Userspace dlmalloc port, supporting syscalls mman_map()/mman_unmap()

kernel/pmm/pmm.c

@@ -57,7 +57,7 @@ void *pmm_alloc(size_t pages) {
 
   if (!phys) {
     ERR("pmm", "phys memory ran out\n");
-    hal_hang();
+    return NULL;
   }
   return (void *)phys;
 }

kernel/proc/proc.c

@@ -169,6 +169,7 @@ Proc *proc_spawnuser(char *mountpoint, char *path) {
   proc->platformdata.trapframe.rip = aux.entry;
   proc->state = PROC_EMBRYO;
   proc->pid = pids++;
+  proc->mman_map_base = PROC_MMAN_MAP_BASE;
   spinlock_init(&proc->bcast_pipes.spinlock);
   spinlock_init(&proc->pipes_spinlock);
 

kernel/proc/proc.h

@@ -18,6 +18,8 @@
 #define PROC_VFSHANDLES_MAX   0x80
 #define PROC_PIPEHANDLES_MAX  0x20
 
+#define PROC_MMAN_MAP_BASE 0xC000000000
+
 typedef struct {
   IntrStackFrame trapframe;
   uint8_t *kstack;
@@ -51,6 +53,8 @@ typedef struct Proc {
     IpcPipe *list;
     SpinLock spinlock;
   } bcast_pipes;
+
+  uint64_t mman_map_base;
 } Proc;
 
 typedef struct {

kernel/syscall/mman.c

@@ -0,0 +1,99 @@
+#include <stdint.h>
+#include "syscall.h"
+#include "mman.h"
+#include "spinlock/spinlock.h"
+#include "proc/proc.h"
+#include "hal/hal.h"
+#include "pmm/pmm.h"
+#include "util/util.h"
+#include "errors.h"
+#include "sysdefs/mman.h"
+#include "bootinfo/bootinfo.h"
+#include "dlmalloc/malloc.h"
+
+int32_t SYSCALL5(sys_mman_map, addr1, size1, prot1, flags1, out1) {
+  uint8_t *addr = (uint8_t *)addr1;
+  size_t size = size1;
+  uint64_t prot = prot1;
+  uint64_t flags = flags1;
+  uint8_t **out = (uint8_t **)out1;
+
+  if (size % HAL_PAGE_SIZE != 0) {
+    if (out != NULL) {
+      *out = NULL;
+    }
+    return E_INVALIDARGUMENT;
+  }
+
+  size_t pages = _DIV_ROUNDUP(size, HAL_PAGE_SIZE);
+  uint8_t *phys = (uint8_t *)pmm_alloc(pages);
+  if (phys == NULL) {
+    return E_NOMEMORY;
+  }
+  hal_memset(VIRT(phys), 0, pages * HAL_PAGE_SIZE);
+  
+  spinlock_acquire(&PROCS.spinlock);
+  Proc *proc = PROCS.current;
+  spinlock_release(&PROCS.spinlock);
+
+  uint8_t *virt = NULL;
+  if (flags & MMAN_MAP_F_FIXED && addr != NULL) {
+    virt = addr;
+  } else {
+    virt = (uint8_t *)proc->mman_map_base;
+    proc->mman_map_base += size;
+  }
+
+  uint64_t pflags = HAL_PG_USER | HAL_PG_PRESENT;
+  if (prot & MMAN_MAP_PF_RW) {
+    pflags |= HAL_PG_RW;
+  }
+
+  hal_vmm_map_range(VIRT(proc->platformdata.cr3), virt, phys, size, pflags);
+  VasRange *range = dlmalloc(sizeof(*range));
+  range->virtstart = virt;
+  range->physstart = phys;
+  range->size = size * HAL_PAGE_SIZE;
+  range->pgflags = pflags;
+  LL_APPEND(proc->vas, range);
+
+  if (out != NULL) {
+    *out = virt;
+  }
+
+  return E_OK;
+}
+
+int32_t SYSCALL1(sys_mman_unmap, addr1) {
+  uint8_t *addr = (uint8_t *)addr1;
+
+  if (addr == NULL) {
+    return E_INVALIDARGUMENT;
+  }
+
+  spinlock_acquire(&PROCS.spinlock);
+  Proc *proc = PROCS.current;
+  spinlock_release(&PROCS.spinlock);
+
+  uint8_t *virt = NULL;
+  VasRange *tofree = NULL;
+
+  VasRange *range = proc->vas;
+  while (range) {
+    if (range->virtstart == addr) {
+      tofree = range;
+      break;
+    }
+    range = range->next;
+  }
+
+  if (tofree == NULL) {
+    return E_INVALIDARGUMENT;
+  }
+
+  hal_vmm_unmap_range(VIRT(proc->platformdata.cr3), tofree->virtstart, tofree->physstart, tofree->size);
+  LL_REMOVE(proc->vas, tofree);
+  pmm_free((uintptr_t)tofree->physstart, tofree->size / HAL_PAGE_SIZE);
+  dlfree(tofree);
+  return E_OK;
+}

kernel/syscall/mman.h

@@ -0,0 +1,9 @@
+#ifndef SYSCALL_MMAN_H_
+#define SYSCALL_MMAN_H_
+
+#include "syscall.h"
+
+int32_t SYSCALL5(sys_mman_map, addr1, size1, prot1, flags1, out1);
+int32_t SYSCALL1(sys_mman_unmap, addr1);
+
+#endif // SYSCALL_MMAN_H_

kernel/syscall/syscall.c

@@ -6,6 +6,7 @@
 #include "sysdefs/syscall.h"
 #include "ioctl.h"
 #include "ipcpipe.h"
+#include "mman.h"
 
 int32_t SYSCALL1(sys_debugprint, string) {
   char *p = (char *)string;
@@ -18,4 +19,6 @@ SyscallFn SYSCALL_TABLE[SYSCALLS_MAX] = {
   [SYS_PROCESSCTL] = &sys_processctl,
   [SYS_IOCTL]      = &sys_ioctl,
   [SYS_IPCPIPE]    = &sys_ipcpipe,
+  [SYS_MMAN_MAP]   = &sys_mman_map,
+  [SYS_MMAN_UNMAP] = &sys_mman_unmap,
 };