Add pgaccess syscall

cw00h · Jan 10, 2023 · ee4d06b · ee4d06b
1 parent 2daef57
commit ee4d06b
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Showing 5 changed files with 41 additions and 7 deletions.
diff --git a/kernel/defs.h b/kernel/defs.h
@@ -104,6 +104,8 @@ void            yield(void);
 int             either_copyout(int user_dst, uint64 dst, void *src, uint64 len);
 int             either_copyin(void *dst, int user_src, uint64 src, uint64 len);
 void            procdump(void);
+int pgaccess(void *base, int len, void *mask);
+
 
 // swtch.S
 void            swtch(struct context*, struct context*);

diff --git a/kernel/proc.c b/kernel/proc.c
@@ -15,6 +15,7 @@ struct proc *initproc;
 int nextpid = 1;
 struct spinlock pid_lock;
 
+extern pte_t *walk(pagetable_t pagetable, uint64 va, int alloc);
 extern void forkret(void);
 static void freeproc(struct proc *p);
 
@@ -675,3 +676,28 @@ procdump(void)
     printf("\n");
   }
 }
+
+
+int pgaccess(void *base, int len, void *mask) {
+  struct proc *p = myproc();
+  unsigned int temp;
+  char *_base = base;
+  pte_t *pte;
+
+  if(len > 32) return -1;
+
+  for(int i = 0; i < len; i++) {
+    if((pte = walk(p->pagetable, (uint64)(_base + PGSIZE * i), 0))) {
+      if(*pte & PTE_A) {
+        *pte &= ~PTE_A;
+        temp |= (1 << i);
+      }
+    }
+    else return -1;
+  }
+
+  if(copyout(p->pagetable, (uint64)mask, (char *)&temp, sizeof(temp)) < 0) {
+    printf("copyout error\n");
+  }
+  return 0;
+}
diff --git a/kernel/riscv.h b/kernel/riscv.h
@@ -343,6 +343,7 @@ sfence_vma()
 #define PTE_W (1L << 2)
 #define PTE_X (1L << 3)
 #define PTE_U (1L << 4) // 1 -> user can access
+#define PTE_A (1L << 6)
 
 // shift a physical address to the right place for a PTE.
 #define PA2PTE(pa) ((((uint64)pa) >> 12) << 10)

diff --git a/kernel/sysproc.c b/kernel/sysproc.c
@@ -76,14 +76,16 @@ sys_sleep(void)
 }
 
 
-#ifdef LAB_PGTBL
-int
-sys_pgaccess(void)
-{
-  // lab pgtbl: your code here.
-  return 0;
+int sys_pgaccess(void) {
+  uint64 base, mask;
+  int len;
+
+  if(argaddr(0, &base) < 0) return -1;
+  if(argint(1, &len) < 0) return -1;
+  if(argaddr(2, &mask) < 0) return -1;
+
+  return pgaccess((void *)base, len, (void *)mask);
 }
-#endif
 
 uint64
 sys_kill(void)
@@ -107,3 +109,4 @@ sys_uptime(void)
   release(&tickslock);
   return xticks;
 }
+
diff --git a/user/user.h b/user/user.h
@@ -2,6 +2,8 @@ struct stat;
 struct rtcdate;
 struct sysinfo;
 
+#define LAB_PGTBL 1
+
 // system calls
 int fork(void);
 int exit(int) __attribute__((noreturn));