1 /* 2 * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7 #include <arch_helpers.h> 8 #include <common/debug.h> 9 #include <lib/utils.h> 10 #include <platform_def.h> 11 12 #include "juno_decl.h" 13 plat_get_stack_protector_canary(void)14u_register_t plat_get_stack_protector_canary(void) 15 { 16 uint64_t entropy; 17 18 if (!juno_getentropy(&entropy)) { 19 ERROR("Not enough entropy to initialize canary value\n"); 20 panic(); 21 } 22 23 if (sizeof(entropy) == sizeof(u_register_t)) { 24 return entropy; 25 } 26 27 return (entropy & 0xffffffffULL) ^ (entropy >> 32); 28 } 29