1*91f16700Schasinglulu/* 2*91f16700Schasinglulu * Copyright (c) 2017, Arm Limited and Contributors. All rights reserved. 3*91f16700Schasinglulu * 4*91f16700Schasinglulu * SPDX-License-Identifier: BSD-3-Clause 5*91f16700Schasinglulu */ 6*91f16700Schasinglulu 7*91f16700Schasinglulu#include <arch.h> 8*91f16700Schasinglulu#include <asm_macros.S> 9*91f16700Schasinglulu#include <assert_macros.S> 10*91f16700Schasinglulu 11*91f16700Schasinglulu .globl update_stack_protector_canary 12*91f16700Schasinglulu 13*91f16700Schasinglulu/* ----------------------------------------------------------------------- 14*91f16700Schasinglulu * void update_stack_protector_canary(void) 15*91f16700Schasinglulu * 16*91f16700Schasinglulu * Change the value of the canary used for stack smashing attacks protection. 17*91f16700Schasinglulu * Note: This must be called when it is safe to call C code, but this cannot be 18*91f16700Schasinglulu * called by C code. Doing this will make the check fail when the calling 19*91f16700Schasinglulu * function returns. 20*91f16700Schasinglulu * ----------------------------------------------------------------------- 21*91f16700Schasinglulu */ 22*91f16700Schasinglulu 23*91f16700Schasinglulufunc update_stack_protector_canary 24*91f16700Schasinglulu /* Use x19 as it is callee-saved */ 25*91f16700Schasinglulu mov x19, x30 26*91f16700Schasinglulu bl plat_get_stack_protector_canary 27*91f16700Schasinglulu 28*91f16700Schasinglulu /* Update the canary with the returned value */ 29*91f16700Schasinglulu adrp x1, __stack_chk_guard 30*91f16700Schasinglulu str x0, [x1, #:lo12:__stack_chk_guard] 31*91f16700Schasinglulu ret x19 32*91f16700Schasingluluendfunc update_stack_protector_canary 33*91f16700Schasinglulu 34*91f16700Schasinglulu 35