lab print a page table finished

kernel/defs.h

@@ -173,6 +173,7 @@ uint64          walkaddr(pagetable_t, uint64);
 int             copyout(pagetable_t, uint64, char *, uint64);
 int             copyin(pagetable_t, char *, uint64, uint64);
 int             copyinstr(pagetable_t, char *, uint64, uint64);
+void            vmprint(pagetable_t, int level); // for pgtbl-lab 2: Print a page table
 
 // plic.c
 void            plicinit(void);

kernel/exec.c

@@ -128,6 +128,11 @@ exec(char *path, char **argv)
   p->trapframe->sp = sp; // initial stack pointer
   proc_freepagetable(oldpagetable, oldsz);
 
+  // pgtbl-lab2: Print a page table
+  if (p->pid == 1) {
+    vmprint(p->pagetable, 0);
+  }
+
   return argc; // this ends up in a0, the first argument to main(argc, argv)
 
  bad:

kernel/vm.c

@@ -437,3 +437,29 @@ copyinstr(pagetable_t pagetable, char *dst, uint64 srcva, uint64 max)
     return -1;
   }
 }
+
+// Created for pgtbl-lab 2: Print a page table
+// Take a pagetable_t argument
+// Print the contents in the certain format
+void
+vmprint(pagetable_t pagetable, int level)
+{
+  if (!level)
+    printf("page table %p\n", pagetable);
+
+  // there are 2^9 = 512 PTEs in a page table.
+  for(int i = 0; i < 512; i++) {
+    pte_t pte = pagetable[i];
+    if (pte & PTE_V) {
+      uint64 child = PTE2PA(pte);
+      for (int j = level+1; j > 0; j--) {
+        printf(" ..");
+      }
+      printf("%d: pte %p pa %p\n", i, pte, child);
+      if ((pte & (PTE_R|PTE_W|PTE_X)) == 0) {
+        // this PTE points to a lower-level page table.
+        vmprint((pagetable_t)child, level+1);
+      }
+    }
+  }
+}