ppc64: Fix clear_user, from ppc32

include/asm-ppc64/uaccess.h

@@ -240,7 +240,11 @@ clear_user(void *addr, unsigned long size)
 {
 	if (access_ok(VERIFY_WRITE, addr, size))
 		return __clear_user(addr, size);
-	return size? -EFAULT: 0;
+	if ((unsigned long)addr < TASK_SIZE) {
+		unsigned long over = (unsigned long)addr + size - TASK_SIZE;
+		return __clear_user(addr, size - over) + over;
+	}
+	return size;
 }
 
 extern int __strncpy_from_user(char *dst, const char *src, long count);