You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
29 lines
811 B
29 lines
811 B
/*
|
|
* 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;
|
|
}
|