/* * 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 1 #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; 	current->stack_canary = canary;	__stack_chk_guard = current->stack_canary;} #endif	/* _ASM_STACKPROTECTOR_H */