lunaix-os/kernel/mm/cow.c

   1 #include <lunaix/mm/pmm.h>
   2 #include <lunaix/mm/vmm.h>
   3
   4 ptr_t
   5 vmm_dup_page(pid_t pid, ptr_t pa)
   6 {
   7     ptr_t new_ppg = pmm_alloc_page(pid, 0);
   8     vmm_set_mapping(VMS_SELF, PG_MOUNT_3, new_ppg, PG_PREM_RW, VMAP_NULL);
   9     vmm_set_mapping(VMS_SELF, PG_MOUNT_4, pa, PG_PREM_RW, VMAP_NULL);
  10
  11     asm volatile("movl %1, %%edi\n"
  12                  "movl %2, %%esi\n"
  13                  "rep movsl\n" ::"c"(1024),
  14                  "r"(PG_MOUNT_3),
  15                  "r"(PG_MOUNT_4)
  16                  : "memory", "%edi", "%esi");
  17
  18     vmm_del_mapping(VMS_SELF, PG_MOUNT_3);
  19     vmm_del_mapping(VMS_SELF, PG_MOUNT_4);
  20
  21     return new_ppg;
  22 }