1 files changed, 30 insertions, 0 deletions
diff --git a/plat/qemu/common/qemu_stack_protector.c b/plat/qemu/common/qemu_stack_protector.c
new file mode 100644
index 0000000..d0b4a0f
--- /dev/null
+++ b/plat/qemu/common/qemu_stack_protector.c
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2021, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdint.h>
+
+#include <arch_helpers.h>
+#include <arch_features.h>
+#include <plat/common/platform.h>
+
+#define RANDOM_CANARY_VALUE ((u_register_t) 3288484550995823360ULL)
+
+u_register_t plat_get_stack_protector_canary(void)
+{
+	/* Use the RNDR instruction if the CPU supports it */
+	if (is_feat_rng_supported()) {
+		return read_rndr();
+	}
+
+	/*
+	 * Ideally, a random number should be returned above. If a random
+	 * number generator is not supported, return instead a
+	 * combination of a timer's value and a compile-time constant.
+	 * This is better than nothing but not necessarily really secure.
+	 */
+	return RANDOM_CANARY_VALUE ^ read_cntpct_el0();
+}
+