[linux-block.git] / arch / arm64 / include / asm / stackprotector.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * GCC stack protector support.
 *
 * Stack protector works by putting predefined pattern at the start of
 * the stack frame and verifying that it hasn't been overwritten when
 * returning from the function.  The pattern is called stack canary
 * and gcc expects it to be defined by a global variable called
 * "__stack_chk_guard" on ARM.  This unfortunately means that on SMP
 * we cannot have a different canary value per task.
 */

#ifndef __ASM_STACKPROTECTOR_H
#define __ASM_STACKPROTECTOR_H

#include <linux/random.h>
#include <linux/version.h>

extern unsigned long __stack_chk_guard;

/*
 * Initialize the stackprotector canary value.
 *
 * NOTE: this must only be called from functions that never return,
 * and it must always be inlined.
 */
static __always_inline void boot_init_stack_canary(void)
{
	unsigned long canary;

	/* Try to get a semi random initial value. */
	get_random_bytes(&canary, sizeof(canary));
	canary ^= LINUX_VERSION_CODE;
	canary &= CANARY_MASK;

	current->stack_canary = canary;
	__stack_chk_guard = current->stack_canary;
}

#endif	/* _ASM_STACKPROTECTOR_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
c0c264ae LA	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
	8	* and gcc expects it to be defined by a global variable called
	9	* "__stack_chk_guard" on ARM. This unfortunately means that on SMP
	10	* we cannot have a different canary value per task.
	11	*/
	12
	13	#ifndef __ASM_STACKPROTECTOR_H
	14	#define __ASM_STACKPROTECTOR_H
	15
	16	#include <linux/random.h>
	17	#include <linux/version.h>
	18
	19	extern unsigned long __stack_chk_guard;
	20
	21	/*
	22	* Initialize the stackprotector canary value.
	23	*
	24	* NOTE: this must only be called from functions that never return,
	25	* and it must always be inlined.
	26	*/
	27	static __always_inline void boot_init_stack_canary(void)
	28	{
	29	unsigned long canary;
	30
	31	/* Try to get a semi random initial value. */
	32	get_random_bytes(&canary, sizeof(canary));
	33	canary ^= LINUX_VERSION_CODE;
d21f5498	34	canary &= CANARY_MASK;
c0c264ae LA	35
	36	current->stack_canary = canary;
	37	__stack_chk_guard = current->stack_canary;
	38	}
	39
	40	#endif /* _ASM_STACKPROTECTOR_H */