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
18 extern 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 */
26 static __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
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