android_kernel_xiaomi_sm7250/drivers/soc/qcom/early_random.c
Reinazhard 3ea8ab7387 random: early_random: Fix races when initializing random pools
Recent random.c upstream introduced random pools init race.
As Jason A. Donenfeld suggests, update the early_random to fix this issue

Suggested-by: Jason A. Donenfeld <Jason@zx2c4.com>
Co-authored-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Reinazhard <reinazhard@gmail.com>
Change-Id: I104bbbb13e55ffbc0f85cc4fdf3cdaaadfdb76b5
2022-11-12 11:22:41 +00:00

56 lines
1.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2013-2014, 2016-2018, The Linux Foundation. All rights
*/
#include <linux/kernel.h>
#include <linux/hw_random.h>
#include <linux/random.h>
#include <linux/io.h>
#include <soc/qcom/scm.h>
#include <asm/cacheflush.h>
#define TZ_SVC_CRYPTO 10
#define PRNG_CMD_ID 0x01
struct tz_prng_data {
uint8_t *out_buf;
uint32_t out_buf_sz;
} __packed;
#define RANDOM_BUFFER_SIZE PAGE_SIZE
char random_buffer[RANDOM_BUFFER_SIZE] __aligned(PAGE_SIZE);
void __init init_random_pool(void)
{
struct tz_prng_data data;
int ret;
struct scm_desc desc;
data.out_buf = (uint8_t *) virt_to_phys(random_buffer);
desc.args[0] = (unsigned long) data.out_buf;
desc.args[1] = data.out_buf_sz = SZ_512;
desc.arginfo = SCM_ARGS(2, SCM_RW, SCM_VAL);
dmac_flush_range(random_buffer, random_buffer + RANDOM_BUFFER_SIZE);
ret = scm_call2(SCM_SIP_FNID(TZ_SVC_CRYPTO, PRNG_CMD_ID), &desc);
if (!ret) {
u64 bytes_received = desc.ret[0];
if (bytes_received != SZ_512)
pr_warn("Did not receive the expected number of bytes from PRNG: %llu\n",
bytes_received);
dmac_inv_range(random_buffer, random_buffer +
RANDOM_BUFFER_SIZE);
bytes_received = (bytes_received <= RANDOM_BUFFER_SIZE) ?
bytes_received : RANDOM_BUFFER_SIZE;
add_bootloader_randomness(random_buffer, bytes_received);
}
}