Tegra: enable stack protection
This patch sets ENABLE_STACK_PROTECTOR=strong and implements
the platform support to generate a stack protection canary value.
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Change-Id: Ia8afe464b5645917b1c77d49305d19c7cd01866a
diff --git a/plat/nvidia/tegra/common/tegra_common.mk b/plat/nvidia/tegra/common/tegra_common.mk
index c946a75..79cc03a 100644
--- a/plat/nvidia/tegra/common/tegra_common.mk
+++ b/plat/nvidia/tegra/common/tegra_common.mk
@@ -1,5 +1,6 @@
#
# Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2020, NVIDIA Corporation. All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause
#
@@ -32,3 +33,7 @@
${COMMON_DIR}/tegra_platform.c \
${COMMON_DIR}/tegra_pm.c \
${COMMON_DIR}/tegra_sip_calls.c
+
+ifneq ($(ENABLE_STACK_PROTECTOR), 0)
+BL31_SOURCES += ${COMMON_DIR}/tegra_stack_protector.c
+endif
diff --git a/plat/nvidia/tegra/common/tegra_stack_protector.c b/plat/nvidia/tegra/common/tegra_stack_protector.c
new file mode 100644
index 0000000..f6c459a
--- /dev/null
+++ b/plat/nvidia/tegra/common/tegra_stack_protector.c
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2020, NVIDIA Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdint.h>
+
+#include <arch_helpers.h>
+#include <lib/mmio.h>
+#include <plat/common/platform.h>
+#include <platform_def.h>
+
+u_register_t plat_get_stack_protector_canary(void)
+{
+ u_register_t seed;
+
+ /*
+ * Ideally, a random number should be returned instead. As the
+ * platform does not have any random number generator, this is
+ * better than nothing, but not really secure.
+ */
+ seed = mmio_read_32(TEGRA_MISC_BASE + HARDWARE_REVISION_OFFSET);
+ seed <<= 32;
+ seed |= mmio_read_32(TEGRA_TMRUS_BASE);
+
+ return seed ^ read_cntpct_el0();
+}