1 files changed, 28 insertions, 0 deletions
diff --git a/plat/arm/common/aarch64/arm_pauth.c b/plat/arm/common/aarch64/arm_pauth.c
new file mode 100644
index 0000000..7cea8a0
--- /dev/null
+++ b/plat/arm/common/aarch64/arm_pauth.c
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2019, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch_helpers.h>
+#include <cdefs.h>
+#include <stdint.h>
+
+/*
+ * This is only a toy implementation to generate a seemingly random
+ * 128-bit key from sp, x30 and cntpct_el0 values.
+ * A production system must re-implement this function to generate
+ * keys from a reliable randomness source.
+ */
+uint128_t plat_init_apkey(void)
+{
+	uint64_t return_addr = (uint64_t)__builtin_return_address(0U);
+	uint64_t frame_addr = (uint64_t)__builtin_frame_address(0U);
+	uint64_t cntpct = read_cntpct_el0();
+
+	/* Generate 128-bit key */
+	uint64_t key_lo = (return_addr << 13) ^ frame_addr ^ cntpct;
+	uint64_t key_hi = (frame_addr << 15) ^ return_addr ^ cntpct;
+
+	return ((uint128_t)(key_hi) << 64) | key_lo;
+}