xv6-vm.c

// Free a page table and all the physical memory pages
// in the user part.
void
freevm(pde_t *pgdir)
{
  uint i, j;
  pte_t *pt;

  if(pgdir == 0)
    panic("freevm: no pgdir");
  deallocuvm(pgdir, KERNBASE, 0);
  for(i = 0; i < NPDENTRIES; i++){
    if(pgdir[i] & PTE_P){
      pt = P2V(PTE_ADDR(pgdir[i]));
      if ( /* is under KERNBASE */) {
        for (j = 0; j < NPTENTRIES; j++) {
          if (pt[j] & PTE_P)
            kfree(P2V(PTE_ADDR(pt[j])));
        }
      }
      kfree(pt);
    }
  }
  kfree((char*)pgdir);
}