1*359acf77SVarun Wadekar /* 2*359acf77SVarun Wadekar * Copyright (c) 2020, NVIDIA Corporation. All rights reserved. 3*359acf77SVarun Wadekar * 4*359acf77SVarun Wadekar * SPDX-License-Identifier: BSD-3-Clause 5*359acf77SVarun Wadekar */ 6*359acf77SVarun Wadekar 7*359acf77SVarun Wadekar #include <stdint.h> 8*359acf77SVarun Wadekar 9*359acf77SVarun Wadekar #include <arch_helpers.h> 10*359acf77SVarun Wadekar #include <lib/mmio.h> 11*359acf77SVarun Wadekar #include <plat/common/platform.h> 12*359acf77SVarun Wadekar #include <platform_def.h> 13*359acf77SVarun Wadekar plat_get_stack_protector_canary(void)14*359acf77SVarun Wadekaru_register_t plat_get_stack_protector_canary(void) 15*359acf77SVarun Wadekar { 16*359acf77SVarun Wadekar u_register_t seed; 17*359acf77SVarun Wadekar 18*359acf77SVarun Wadekar /* 19*359acf77SVarun Wadekar * Ideally, a random number should be returned instead. As the 20*359acf77SVarun Wadekar * platform does not have any random number generator, this is 21*359acf77SVarun Wadekar * better than nothing, but not really secure. 22*359acf77SVarun Wadekar */ 23*359acf77SVarun Wadekar seed = mmio_read_32(TEGRA_MISC_BASE + HARDWARE_REVISION_OFFSET); 24*359acf77SVarun Wadekar seed <<= 32; 25*359acf77SVarun Wadekar seed |= mmio_read_32(TEGRA_TMRUS_BASE); 26*359acf77SVarun Wadekar 27*359acf77SVarun Wadekar return seed ^ read_cntpct_el0(); 28*359acf77SVarun Wadekar } 29