task4 finished

kernel/sysproc.c

@@ -126,38 +126,40 @@ sys_uptime(void)
 
 uint64
 sys_pgaccess(void)
-{
-  uint64 va;
-  int n;
-  uint64 user_mask_addr;
-  argaddr(0, &va);
-  argint(1, &n);
-  argaddr(2, &user_mask_addr);
-  if (va < 0 || n < 0 || user_mask_addr < 0)
-    return -1;
-
-  if (n < 0 || n > 32)
-    return -1;
-
+ {
+   // lab pgtbl: your code here.
   struct proc *p = myproc();
-  uint64 mask = 0;
+  unsigned int abits=0;
 
-  for (int i = 0; i < n; i++) {
-    uint64 v = va + i * PGSIZE;
-    pte_t *pte = walk(p->pagetable, v, 0);
+  uint64 addr;
+  argaddr(0, &addr);
 
-    if (!pte || (*pte & PTE_PS))
-      continue;
+  int num;
+  argint(1,&num);
 
-    if ((*pte & PTE_V) && (*pte & PTE_A)) {
-      mask |= (1 << i);       // Set bit i in mask
-      *pte &= ~PTE_A;         // Clear the Accessed bit
+  uint64 dest;
+  argaddr(2, &dest);
+
+
+  for(int i=0;i<num;i++){
+    uint64 query_addr = addr + i * PGSIZE ;
+
+
+    pte_t * pte=walk(p->pagetable, query_addr, 0);
+    if(*pte&PTE_A)
+    {
+      abits=abits|(1<<i);
+      *pte=(*pte)&(~PTE_A);
     }
+
   }
 
-  if (copyout(p->pagetable, user_mask_addr, (char*)&mask, sizeof(mask)) < 0)
+
+
+  if(copyout(p->pagetable,dest,(char*)&abits, sizeof(abits)) < 0)
     return -1;
 
-  return 0;
-}
 
+
+   return 0;
+ }