Virtual memory and dlmalloc

kernel/vmm/vmm.c

@@ -0,0 +1,52 @@
+#include <stddef.h>
+#include <stdint.h>
+#include "bitmap/bitmap.h"
+#include "spinlock/spinlock.h"
+#include "bootinfo/bootinfo.h"
+#include "vmm.h"
+#include "kprintf.h"
+#include "util/util.h"
+#include "hal/hal.h"
+#include "pmm/pmm.h"
+#include "paging/paging.h"
+
+#define POS_ENSURE 0x40000000
+
+#define PAGE_SIZE 0x1000
+
+VirtMem VIRT_MEM;
+
+void vmm_init(void) {
+  spinlock_init(&VIRT_MEM.spinlock);
+  BitMap *bm = &VIRT_MEM.self;
+
+  size_t targetpos = _DIV_ROUNDUP(BOOT_INFO.hhdm_off - BOOT_INFO.memmap_total - POS_ENSURE, PAGE_SIZE) * PAGE_SIZE;
+  bm->init = false;
+
+  bm->mem_start = targetpos;
+  bm->nblocks = _DIV_ROUNDUP(BOOT_INFO.memmap_total, BITMAP_BLOCK_SIZE);
+  bm->nbytes = _DIV_ROUNDUP(bm->nblocks, 8);
+
+  uint64_t pagesrequired = _DIV_ROUNDUP(bm->nbytes, BITMAP_BLOCK_SIZE);
+  bm->map = (uint8_t *)vmm_alloc(pagesrequired);
+  hal_memset(bm->map, 0, bm->nbytes);
+
+  bm->init = true;
+}
+
+void *vmm_alloc(size_t pages) {
+  size_t phys = (size_t)pmm_alloc(pages);
+  uint64_t out = phys + BOOT_INFO.hhdm_off;
+  return (void *)out;
+}
+
+
+void vmm_free(void *ptr, size_t pages) {
+  size_t phys = paging_virt2phys((size_t)ptr);
+  if (!phys) {
+    ERR("vmm", "could not find phys addr for %p\n", ptr);
+    hal_hang();
+  }
+  pmm_free(phys, pages);
+}
+

kernel/vmm/vmm.h

@@ -0,0 +1,19 @@
+#ifndef VMM_VMM_H_
+#define VMM_VMM_H_
+
+#include <stddef.h>
+#include "bitmap/bitmap.h"
+#include "spinlock/spinlock.h"
+
+typedef struct {
+  SpinLock spinlock;
+  BitMap self;
+} VirtMem;
+
+extern VirtMem VIRT_MEM;
+
+void vmm_init(void);
+void *vmm_alloc(size_t pages);
+void vmm_free(void *ptr, size_t pages);
+
+#endif //  VMM_VMM_H_