plat/arm/board/fvp/fvp_stack_protector.c

   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 <platform.h>
   9 #include <stdint.h>
  10
  11 #define RANDOM_CANARY_VALUE ((u_register_t) 3288484550995823360ULL)
  12
  13 u_register_t plat_get_stack_protector_canary(void)
  14 {
  15         /*
  16          * Ideally, a random number should be returned instead of the
  17          * combination of a timer's value and a compile-time constant. As the
  18          * FVP does not have any random number generator, this is better than
  19          * nothing but not necessarily really secure.
  20          */
  21         return RANDOM_CANARY_VALUE ^ read_cntpct_el0();
  22 }
  23