diff options
Diffstat (limited to 'plat/arm/common/aarch64/arm_pauth.c')
-rw-r--r-- | plat/arm/common/aarch64/arm_pauth.c | 32 |
1 files changed, 32 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 0000000000..c8471190a9 --- /dev/null +++ b/plat/arm/common/aarch64/arm_pauth.c @@ -0,0 +1,32 @@ +/* + * Copyright (c) 2019, Arm Limited. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <cdefs.h> +#include <stdint.h> + +/* + * Instruction pointer authentication key A. The low 64-bit are at [0], and the + * high bits at [1]. They are run-time constants so they are placed in the + * rodata section. They are written before MMU is turned on and the permissions + * are effective. + */ +uint64_t plat_apiakey[2] __section("rodata.apiakey"); + +/* + * This is only a toy implementation to generate a seemingly random 128-bit key + * from sp and x30 values. A production system must re-implement this function + * to generate keys from a reliable randomness source. + */ +uint64_t *plat_init_apiakey(void) +{ + uintptr_t return_addr = (uintptr_t)__builtin_return_address(0U); + uintptr_t frame_addr = (uintptr_t)__builtin_frame_address(0U); + + plat_apiakey[0] = (return_addr << 13) ^ frame_addr; + plat_apiakey[1] = (frame_addr << 15) ^ return_addr; + + return plat_apiakey; +} |