1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * GCC stack protector support.
4 *
5 * Stack protector works by putting predefined pattern at the start of
6 * the stack frame and verifying that it hasn't been overwritten when
7 * returning from the function. The pattern is called stack canary and
8 * on LoongArch gcc expects it to be defined by a global variable called
9 * "__stack_chk_guard".
10 */
11
12#ifndef _ASM_STACKPROTECTOR_H
13#define _ASM_STACKPROTECTOR_H
14
15#include <linux/random.h>
16#include <linux/version.h>
17
18extern unsigned long __stack_chk_guard;
19
20/*
21 * Initialize the stackprotector canary value.
22 *
23 * NOTE: this must only be called from functions that never return,
24 * and it must always be inlined.
25 */
26static __always_inline void boot_init_stack_canary(void)
27{
28	unsigned long canary;
29
30	/* Try to get a semi random initial value. */
31	get_random_bytes(&canary, sizeof(canary));
32	canary ^= LINUX_VERSION_CODE;
33
34	current->stack_canary = canary;
35	__stack_chk_guard = current->stack_canary;
36}
37
38#endif	/* _ASM_STACKPROTECTOR_H */
39