Big code refactor, get rid of HAL entirely

kernel/vmm/vmm.c

@@ -0,0 +1,127 @@
+#include <stddef.h>
+#include <stdint.h>
+#include "vmm/vmm.h"
+#include "bootinfo/bootinfo.h"
+#include "pmm/pmm.h"
+#include "proc/proc.h"
+#include "spinlock/spinlock.h"
+#include "std/string.h"
+#include "kprintf.h"
+
+uint64_t KERNEL_CR3 = 0;
+SpinLock spinlock;
+
+uint64_t vmm_current_cr3(void) {
+  uint64_t cr3;
+  asm volatile("mov %%cr3, %0" : "=r"(cr3));
+  return cr3;
+}
+
+PgIndex vmm_pageindex(uint64_t vaddr) {
+  PgIndex ret;
+
+  ret.pml4 = (vaddr >> 39) & 0x1ff;
+  ret.pml3 = (vaddr >> 30) & 0x1ff;
+  ret.pml2 = (vaddr >> 21) & 0x1ff;
+  ret.pml1 = (vaddr >> 12) & 0x1ff;
+
+  return ret;
+}
+
+uint64_t *vmm_nexttable(uint64_t *table, uint64_t ent, bool alloc) {
+  uint64_t entry = table[ent];
+  uint64_t phys;
+  if (entry & VMM_PG_PRESENT) {
+    phys = entry & ~0xFFFULL;
+  } else {
+    if (!alloc) {
+      return NULL;
+    }
+
+    uint8_t *newphys = pmm_alloc(1);
+    phys = (uint64_t)newphys;
+    memset(VIRT(phys), 0, VMM_PAGE_SIZE);
+    table[ent] = phys | VMM_PG_USER | VMM_PG_RW | VMM_PG_PRESENT;
+  }
+  return (uint64_t *)((uint8_t *)VIRT(phys));
+}
+
+void vmm_map_page(uint64_t cr3phys, uint64_t virtaddr, uint64_t physaddr, uint32_t flags) {
+  uint64_t *pml4 = (uint64_t *)VIRT(cr3phys);
+  PgIndex pi = vmm_pageindex(virtaddr);
+
+  uint64_t *pml3 = vmm_nexttable(pml4, pi.pml4, true);
+  uint64_t *pml2 = vmm_nexttable(pml3, pi.pml3, true);
+  uint64_t *pml1 = vmm_nexttable(pml2, pi.pml2, true);
+  uint64_t *pte = &pml1[pi.pml1];
+
+  *pte = (physaddr & ~0xFFFULL) | ((uint64_t)flags & 0x7ULL);
+}
+
+void vmm_unmap_page(uint64_t cr3phys, uint64_t virtaddr) {
+  uint64_t *pml4 = (uint64_t *)VIRT(cr3phys);
+  PgIndex pi = vmm_pageindex(virtaddr);
+  
+  uint64_t *pml3 = vmm_nexttable(pml4, pi.pml4, false);
+  uint64_t *pml2 = vmm_nexttable(pml3, pi.pml3, false);
+  uint64_t *pml1 = vmm_nexttable(pml2, pi.pml2, false);
+  uint64_t *pte = &pml1[pi.pml1];
+
+  *pte &= ~VMM_PG_PRESENT;
+}
+
+void vmm_map_range(uint64_t cr3phys, void *virtstart, void *physstart, size_t size, uint32_t flags) {
+  if (size % VMM_PAGE_SIZE != 0 || (uint64_t)virtstart % VMM_PAGE_SIZE != 0 || (uint64_t)physstart % VMM_PAGE_SIZE != 0) {
+    return;
+  }
+
+  spinlock_acquire(&spinlock);
+  uint8_t *vaddr = (uint8_t *)virtstart;
+  uint8_t *paddr = (uint8_t *)physstart;
+  uint8_t *end = (uint8_t *)virtstart + size;
+  for (; vaddr < end; vaddr += VMM_PAGE_SIZE, paddr += VMM_PAGE_SIZE) {
+    vmm_map_page(cr3phys, (uint64_t)vaddr, (uint64_t)paddr, flags);
+  }
+  spinlock_release(&spinlock);
+}
+
+void vmm_unmap_range(uint64_t cr3phys, void *virtstart, void *physstart, size_t size) {
+  if (size % VMM_PAGE_SIZE != 0 || (uint64_t)virtstart % VMM_PAGE_SIZE != 0 || (uint64_t)physstart % VMM_PAGE_SIZE != 0) {
+    return;
+  }
+
+  spinlock_acquire(&spinlock);
+  uint8_t *vaddr = (uint8_t *)virtstart;
+  uint8_t *end = vaddr + size;
+
+  for (; vaddr < end; vaddr += VMM_PAGE_SIZE) {
+    vmm_unmap_page(cr3phys, (uint64_t)vaddr);
+  }
+  spinlock_release(&spinlock);
+}
+
+void vmm_map_kern(uint64_t targetcr3) {
+  uint64_t *kcr3 = (uint64_t *)VIRT(KERNEL_CR3);
+  uint64_t *cr3 = (uint64_t *)VIRT(targetcr3);
+  for (size_t i = 0; i < 512; i++) {
+    cr3[i] = kcr3[i];
+  }
+}
+
+uint64_t vmm_userproc_pml4_phys(void) {
+  uint8_t *cr3phys = pmm_alloc(1);
+  uint64_t phys = (uint64_t)cr3phys;
+  memset(VIRT(phys), 0, VMM_PAGE_SIZE);
+
+  uint64_t *kcr3 = (uint64_t *)VIRT(KERNEL_CR3);
+  uint64_t *pml4 = (uint64_t *)VIRT(phys);
+  for (size_t i = 256; i < 512; i++) {
+    pml4[i] = kcr3[i];
+  }
+  return phys;
+}
+
+void vmm_init(void) {
+  spinlock_init(&spinlock);
+  KERNEL_CR3 = vmm_current_cr3();
+}

kernel/vmm/vmm.h

@@ -0,0 +1,65 @@
+#ifndef VMM_VMM_H_
+#define VMM_VMM_H_
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include "compiler/attr.h"
+
+#define VMM_PAGE_SIZE 0x1000
+
+#define VIRT(X) ((void *)(BOOT_INFO.hhdm_off + (uint64_t)(X)))
+
+typedef struct VasRange {
+  struct VasRange *next;
+
+  uint8_t *virtstart;
+  uint8_t *physstart;
+  size_t size;
+  uint8_t pgflags;
+} PACKED VasRange;
+
+enum {
+  VMM_PG_PRESENT = 1<<0,
+  VMM_PG_RW      = 1<<1,
+  VMM_PG_USER    = 1<<2,
+};
+
+typedef struct {
+  uint16_t pml4;
+  uint16_t pml3;
+  uint16_t pml2;
+  uint16_t pml1;
+} PACKED PgIndex;
+
+typedef struct {
+  bool present: 1;
+  bool rw: 1;
+  bool user: 1;
+  bool writethrough: 1;
+  bool cachedisabled: 1;
+  bool accessed: 1;
+  bool dirty: 1;
+  bool hugepage: 1;
+  bool global: 1;
+  uint8_t avail: 3;
+  uint64_t addr: 40;
+  uint16_t osdef: 11;
+  bool nx: 1;
+} PACKED Pte;
+
+typedef struct {
+  Pte ents[512];
+} PACKED PgTable;
+
+extern uint64_t KERNEL_CR3;
+
+void vmm_init(void);
+void vmm_unmap_page(uint64_t cr3phys, uint64_t virtaddr);
+void vmm_map_page(uint64_t cr3phys, uint64_t virtaddr, uint64_t physaddr, uint32_t flags);
+uint64_t vmm_current_cr3(void);
+void vmm_map_range(uint64_t cr3phys, void *virtstart, void *physstart, size_t size, uint32_t flags);
+void vmm_unmap_range(uint64_t cr3phys, void *virtstart, void *physstart, size_t size);
+uint64_t vmm_userproc_pml4_phys(void);
+
+#endif // VMM_VMM_H_