vm_map.c

#include <stdc.h>
#include <vm_pager.h>
#include <vm_object.h>
#include <vm_map.h>
#include <errno.h>

static void paging_on_demand_and_memory_protection_demo() {
  vm_map_activate(vm_map_new());

  vm_map_t *kmap = get_kernel_vm_map();
  vm_map_t *umap = get_user_vm_map();

  log("Kernel physical map : %08lx-%08lx", kmap->pmap->start, kmap->pmap->end);
  log("User physical map   : %08lx-%08lx", umap->pmap->start, umap->pmap->end);

  vm_addr_t start = 0x1001000;
  vm_addr_t end = 0x1001000 + 2 * PAGESIZE;

  vm_map_entry_t *redzone0 =
    vm_map_add_entry(umap, start - PAGESIZE, start, VM_PROT_NONE);
  vm_map_entry_t *redzone1 =
    vm_map_add_entry(umap, end, end + PAGESIZE, VM_PROT_NONE);
  vm_map_entry_t *data =
    vm_map_add_entry(umap, start, end, VM_PROT_READ | VM_PROT_WRITE);

  redzone0->object = vm_object_alloc();
  redzone1->object = vm_object_alloc();
  data->object = default_pager->pgr_alloc();

  vm_map_dump(umap);
  vm_map_dump(kmap);

  /* Start in paged on demand range, but end outside, to cause fault */
  for (int *ptr = (int *)start; ptr != (int *)end; ptr += 256) {
    log("%p", ptr);
    *ptr = 0xfeedbabe;
  }

  vm_map_dump(umap);
  vm_map_dump(kmap);

  log("Test passed.");
}

void findspace_demo() {
  vm_map_t *umap = vm_map_new();
  vm_map_activate(umap);

#define addr1 0x10000000
#define addr2 0x30000000
  vm_map_add_entry(umap, addr1, addr2, VM_PROT_NONE);
#define addr3 0x30005000
#define addr4 0x60000000
  vm_map_add_entry(umap, addr3, addr4, VM_PROT_NONE);

  vm_addr_t t;
  int n;
  n = vm_map_findspace(umap, 0x00010000, PAGESIZE, &t);
  assert(n == 0 && t == 0x00010000);

  n = vm_map_findspace(umap, addr1, PAGESIZE, &t);
  assert(n == 0 && t == addr2);

  n = vm_map_findspace(umap, addr1 + 20 * PAGESIZE, PAGESIZE, &t);
  assert(n == 0 && t == addr2);

  n = vm_map_findspace(umap, addr1, 0x6000, &t);
  assert(n == 0 && t == addr4);

  n = vm_map_findspace(umap, addr1, 0x5000, &t);
  assert(n == 0 && t == addr2);

  /* Fill the gap exactly */
  vm_map_add_entry(umap, t, t + 0x5000, VM_PROT_NONE);

  n = vm_map_findspace(umap, addr1, 0x5000, &t);
  assert(n == 0 && t == addr4);

  n = vm_map_findspace(umap, addr4, 0x6000, &t);
  assert(n == 0 && t == addr4);

  n = vm_map_findspace(umap, 0, 0x40000000, &t);
  assert(n == -ENOMEM);

  log("Test passed.");
}

int main() {
  paging_on_demand_and_memory_protection_demo();
  findspace_demo();
  return 0;
}