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>
diff --git a/plat/rockchip/common/rockchip_stack_protector.c b/plat/rockchip/common/rockchip_stack_protector.c
new file mode 100644
index 0000000..1898977
--- /dev/null
+++ b/plat/rockchip/common/rockchip_stack_protector.c
@@ -0,0 +1,24 @@
+/*
+ * 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();
+}
+