arch/x86/include/asm/stackprotector.h

Source file repositories/reference/linux-study-clean/arch/x86/include/asm/stackprotector.h

File Facts

System
Linux kernel
Corpus path
arch/x86/include/asm/stackprotector.h
Extension
.h
Size
1599 bytes
Lines
58
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _ASM_STACKPROTECTOR_H
#define _ASM_STACKPROTECTOR_H 1

#ifdef CONFIG_STACKPROTECTOR

#include <asm/tsc.h>
#include <asm/processor.h>
#include <asm/percpu.h>
#include <asm/desc.h>

#include <linux/sched.h>

DECLARE_PER_CPU_CACHE_HOT(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.
 *
 * In addition, it should be called from a compilation unit for which
 * stack protector is disabled. Alternatively, the caller should not end
 * with a function call which gets tail-call optimized as that would
 * lead to checking a modified canary value.
 */
static __always_inline void boot_init_stack_canary(void)
{
	unsigned long canary = get_random_canary();

	current->stack_canary = canary;
	this_cpu_write(__stack_chk_guard, canary);
}

static inline void cpu_init_stack_canary(int cpu, struct task_struct *idle)
{
	per_cpu(__stack_chk_guard, cpu) = idle->stack_canary;
}

#else	/* STACKPROTECTOR */

/* dummy boot_init_stack_canary() is defined in linux/stackprotector.h */

static inline void cpu_init_stack_canary(int cpu, struct task_struct *idle)
{ }

#endif	/* STACKPROTECTOR */
#endif	/* _ASM_STACKPROTECTOR_H */

Annotation

Implementation Notes