blob: 7cea8a0c93bc5bfdf14a0526307a16b74770a087 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
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;
}
|
