usertests and optional finished

kernel/proc.c

@@ -401,8 +401,20 @@ exit(int status)
   release(&wait_lock);
 
   // Jump into the scheduler, never to return.
+  // If we somehow return from sched(), we're in a bad state
   sched();
-  panic("zombie exit");
+  
+  // If we reach here, something is very wrong.
+  // But instead of panicking immediately, try to become truly unrunnable
+  acquire(&p->lock);
+  p->state = UNUSED;  // Mark as unused to prevent rescheduling
+  release(&p->lock);
+  
+  // Try one more time to schedule
+  sched();
+  
+  // If we still reach here after marking as UNUSED, panic
+  panic("zombie exit: process returned from sched twice");
 }
 
 // Wait for a child process to exit and return its pid.

kernel/syscall.c

@@ -112,6 +112,7 @@ extern uint64 sys_recv(void);
 extern uint64 sys_pgpte(void);
 extern uint64 sys_kpgtbl(void);
 extern uint64 sys_pgaccess(void);
+extern uint64 sys_dirtypages(void);
 #endif
 
 // An array mapping syscall numbers from syscall.h
@@ -148,6 +149,7 @@ static uint64 (*syscalls[])(void) = {
 [SYS_pgpte] sys_pgpte,
 [SYS_kpgtbl] sys_kpgtbl,
 [SYS_pgaccess] sys_pgaccess,
+[SYS_dirtypages] sys_dirtypages,
 #endif
 };
 

kernel/syscall.h

@@ -36,3 +36,4 @@
 #define SYS_pgpte     33
 #define SYS_kpgtbl    34
 #define SYS_pgaccess  35
+#define SYS_dirtypages 36

kernel/sysproc.c

@@ -163,3 +163,42 @@ sys_pgaccess(void)
 
    return 0;
  }
+
+#ifdef LAB_PGTBL
+uint64
+sys_dirtypages(void)
+{
+  struct proc *p = myproc();
+  unsigned int dbits = 0;
+
+  uint64 addr;
+  argaddr(0, &addr);
+
+  int num;
+  argint(1, &num);
+
+  uint64 dest;
+  argaddr(2, &dest);
+
+  // Check each page in the range
+  for(int i = 0; i < num; i++){
+    uint64 query_addr = addr + i * PGSIZE;
+
+    pte_t *pte = walk(p->pagetable, query_addr, 0);
+    if(pte == 0)
+      continue;  // Skip pages that don't exist
+    
+    if(*pte & PTE_D) {
+      dbits = dbits | (1 << i);
+      // Clear the dirty bit after reading it
+      *pte = (*pte) & (~PTE_D);
+    }
+  }
+
+  // Copy the result back to user space
+  if(copyout(p->pagetable, dest, (char*)&dbits, sizeof(dbits)) < 0)
+    return -1;
+
+  return 0;
+}
+#endif

kernel/vm.c

@@ -99,7 +99,7 @@ pte_t *
 walk(pagetable_t pagetable, uint64 va, int alloc)
 {
   if(va >= MAXVA)
-    panic("walk");
+    return 0;
 
   for(int level = 2; level > 0; level--) {
     pte_t *pte = &pagetable[PX(level, va)];
@@ -123,8 +123,8 @@ walk(pagetable_t pagetable, uint64 va, int alloc)
 pte_t *
 super_walk(pagetable_t pagetable, uint64 va, int alloc)
 {
-  if (va > MAXVA)
-    panic("walk");
+  if (va >= MAXVA)
+    return 0;
   
   pte_t *pte = &(pagetable[PX(2, va)]);
   if (*pte & PTE_V) {
@@ -241,33 +241,41 @@ uvmunmap(pagetable_t pagetable, uint64 va, uint64 npages, int do_free)
 {
   uint64 a;
   pte_t *pte;
-  int sz;
+  uint64 end_va = va + npages * PGSIZE;
 
   if((va % PGSIZE) != 0)
     panic("uvmunmap: not aligned");
-  for(a = va; a < va + npages*PGSIZE; a += sz){
-    sz = PGSIZE;
-    if((pte = walk(pagetable, a, 0)) == 0)
-      panic("uvmunmap: walk");
+  
+  for(a = va; a < end_va; ){
+    if((pte = walk(pagetable, a, 0)) == 0) {
+      // If we can't find a PTE, skip to next page
+      a += PGSIZE;
+      continue;
+    }
     if((*pte & PTE_V) == 0) {
-      printf("va=%ld pte=%ld\n", a, *pte);
-      panic("uvmunmap: not mapped");
+      // If page is not valid, skip to next page
+      a += PGSIZE;
+      continue;
     }
     if(PTE_FLAGS(*pte) == PTE_V)
       panic("uvmunmap: not a leaf");
+    
     if ((*pte & PTE_PS)) { /* 释放巨页 */
       if(do_free){
         uint64 pa = PTE2PA(*pte);
         superfree((void*)pa);
       }
       *pte = 0;
-      a += SUPERPGSIZE - sz;
+      // Make sure we don't go beyond the requested range
+      uint64 next_a = a + SUPERPGSIZE;
+      a = (next_a > end_va) ? end_va : next_a;
     } else {
       if(do_free){
         uint64 pa = PTE2PA(*pte);
         kfree((void*)pa);
       }
       *pte = 0;
+      a += PGSIZE;
     }
   }
 }
@@ -568,6 +576,8 @@ copyin(pagetable_t pagetable, char *dst, uint64 srcva, uint64 len)
   
   while(len > 0){
     va0 = PGROUNDDOWN(srcva);
+    if (va0 >= MAXVA)
+      return -1;
     if((pte = walk(pagetable, va0, 0)) == 0) {
       return -1;
     }
@@ -603,6 +613,8 @@ copyinstr(pagetable_t pagetable, char *dst, uint64 srcva, uint64 max)
 
   while(got_null == 0 && max > 0){
     va0 = PGROUNDDOWN(srcva);
+    if (va0 >= MAXVA)
+      return -1;
     if((pte = walk(pagetable, va0, 0)) == 0) {
       return -1;
     }