| Antonio Nino Diaz | 9c9f92c | 2019-03-13 13:57:39 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (c) 2019, Arm Limited. All rights reserved. |
| 3 | * |
| 4 | * SPDX-License-Identifier: BSD-3-Clause |
| 5 | */ |
| 6 | |
| 7 | #include <cdefs.h> |
| 8 | #include <stdint.h> |
| 9 | |
| 10 | /* |
| 11 | * Instruction pointer authentication key A. The low 64-bit are at [0], and the |
| 12 | * high bits at [1]. |
| 13 | */ |
| 14 | static uint64_t plat_apiakey[2]; |
| 15 | |
| 16 | /* |
| 17 | * This is only a toy implementation to generate a seemingly random 128-bit key |
| 18 | * from sp and x30 values. |
| 19 | */ |
| 20 | uint64_t *plat_init_apiakey(void) |
| 21 | { |
| 22 | uintptr_t return_addr = (uintptr_t)__builtin_return_address(0U); |
| 23 | uintptr_t frame_addr = (uintptr_t)__builtin_frame_address(0U); |
| 24 | |
| 25 | plat_apiakey[0] = (return_addr << 13) ^ frame_addr; |
| 26 | plat_apiakey[1] = (frame_addr << 15) ^ return_addr; |
| 27 | |
| 28 | return plat_apiakey; |
| 29 | } |