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laurenw-arm7c7b1982020-10-21 13:34:40 -05001/*
2 * Copyright (c) 2021, ARM Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7#include <stdint.h>
8
9#include <arch_helpers.h>
10#include <plat/common/platform.h>
11
12#define RANDOM_CANARY_VALUE ((u_register_t) 8092347823957523895ULL)
13
14u_register_t plat_get_stack_protector_canary(void)
15{
16 /*
17 * Ideally, a random number should be returned instead of the
18 * combination of a timer's value and a compile-time constant. As the
19 * FVP_R does not have any random number generator, this is better than
20 * nothing but not necessarily really secure.
21 */
22 return RANDOM_CANARY_VALUE ^ read_cntpct_el0();
23}
24