rockchip: Add support for the stack protector

It uses the system timer as "entropy" source in the same
way as QEMU, layerscape and others.

Change-Id: Icda17b78e85255bea96109ca2ee0e091187d62ac
Signed-off-by: Christoph Müllner <christophm30@gmail.com>

plat/rockchip/common/rockchip_stack_protector.c

+/*
+ * Copyright (c) 2018-2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdint.h>
+
+#include <arch_helpers.h>
+#include <plat/common/platform.h>
+
+#define RANDOM_CANARY_VALUE ((u_register_t) 3288484550995823360ULL)
+
+u_register_t plat_get_stack_protector_canary(void)
+{
+	/*
+	 * Ideally, a random number should be returned instead of the
+	 * combination of a timer's value and a compile-time constant.
+	 * As the virt platform does not have any random number generator,
+	 * this is better than nothing but not necessarily really secure.
+	 */
+	return RANDOM_CANARY_VALUE ^ read_cntpct_el0();
+}
+

plat/rockchip/px30/platform.mk

@@ -36,6 +36,10 @@ PLAT_BL_COMMON_SOURCES	:=	lib/bl_aux_params/bl_aux_params.c		\
 				lib/xlat_tables/aarch64/xlat_tables.c		\
 				plat/common/plat_psci_common.c
 
+ifneq (${ENABLE_STACK_PROTECTOR},0)
+PLAT_BL_COMMON_SOURCES	+=	${RK_PLAT_COMMON}/rockchip_stack_protector.c
+endif
+
 BL31_SOURCES		+=	${RK_GIC_SOURCES}				\
 				common/desc_image_load.c			\
 				drivers/arm/cci/cci.c				\

plat/rockchip/rk3328/platform.mk

@@ -35,6 +35,10 @@ PLAT_BL_COMMON_SOURCES	:=	common/desc_image_load.c			\
 				plat/common/aarch64/crash_console_helpers.S	\
 				plat/common/plat_psci_common.c
 
+ifneq (${ENABLE_STACK_PROTECTOR},0)
+PLAT_BL_COMMON_SOURCES	+=	${RK_PLAT_COMMON}/rockchip_stack_protector.c
+endif
+
 BL31_SOURCES		+=	${RK_GIC_SOURCES}				\
 				drivers/arm/cci/cci.c				\
 				drivers/ti/uart/aarch64/16550_console.S		\

plat/rockchip/rk3368/platform.mk

@@ -33,6 +33,10 @@ PLAT_BL_COMMON_SOURCES	:=	common/desc_image_load.c			\
 				plat/common/aarch64/crash_console_helpers.S	\
 				plat/common/plat_psci_common.c
 
+ifneq (${ENABLE_STACK_PROTECTOR},0)
+PLAT_BL_COMMON_SOURCES	+=	${RK_PLAT_COMMON}/rockchip_stack_protector.c
+endif
+
 BL31_SOURCES		+=	${RK_GIC_SOURCES}				\
 				drivers/arm/cci/cci.c				\
 				drivers/ti/uart/aarch64/16550_console.S		\

plat/rockchip/rk3399/platform.mk

@@ -38,6 +38,10 @@ PLAT_BL_COMMON_SOURCES	:=	common/desc_image_load.c			\
 				plat/common/aarch64/crash_console_helpers.S \
 				plat/common/plat_psci_common.c
 
+ifneq (${ENABLE_STACK_PROTECTOR},0)
+PLAT_BL_COMMON_SOURCES	+=	${RK_PLAT_COMMON}/rockchip_stack_protector.c
+endif
+
 BL31_SOURCES	+=	${RK_GIC_SOURCES}				\
 			drivers/arm/cci/cci.c				\
 			drivers/ti/uart/aarch64/16550_console.S		\