lunaix-os/kernel/mm/cow.c

   1 #include <lunaix/mm/pmm.h>
   2 #include <lunaix/mm/vmm.h>
   3
   4 #include <sys/mm/mempart.h>
   5
   6 ptr_t
   7 vmm_dup_page(pid_t pid, ptr_t pa)
   8 {
   9     ptr_t new_ppg = pmm_alloc_page(pid, 0);
  10     vmm_set_mapping(VMS_SELF, PG_MOUNT_3, new_ppg, PG_PREM_RW, VMAP_NULL);
  11     vmm_set_mapping(VMS_SELF, PG_MOUNT_4, pa, PG_PREM_RW, VMAP_NULL);
  12
  13     asm volatile("movl %1, %%edi\n"
  14                  "movl %2, %%esi\n"
  15                  "rep movsl\n" ::"c"(1024),
  16                  "r"(PG_MOUNT_3),
  17                  "r"(PG_MOUNT_4)
  18                  : "memory", "%edi", "%esi");
  19
  20     vmm_del_mapping(VMS_SELF, PG_MOUNT_3);
  21     vmm_del_mapping(VMS_SELF, PG_MOUNT_4);
  22
  23     return new_ppg;
  24 }