1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * purgatory: Runs between two kernels 4 * 5 * Copyright (C) 2014 Red Hat Inc. 6 * 7 * Author: 8 * Vivek Goyal <vgoyal@redhat.com> 9 */ 10 11#include <linux/bug.h> 12#include <linux/kernel.h> 13#include <linux/types.h> 14#include <crypto/sha2.h> 15#include <asm/purgatory.h> 16 17#include "../boot/compressed/error.h" 18#include "../boot/string.h" 19 20u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory"); 21 22struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory"); 23 24static int verify_sha256_digest(void) 25{ 26 struct kexec_sha_region *ptr, *end; 27 u8 digest[SHA256_DIGEST_SIZE]; 28 struct sha256_state sctx; 29 30 sha256_init(&sctx); 31 end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions); 32 33 for (ptr = purgatory_sha_regions; ptr < end; ptr++) 34 sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len); 35 36 sha256_final(&sctx, digest); 37 38 if (memcmp(digest, purgatory_sha256_digest, sizeof(digest))) 39 return 1; 40 41 return 0; 42} 43 44void purgatory(void) 45{ 46 int ret; 47 48 ret = verify_sha256_digest(); 49 if (ret) { 50 /* loop forever */ 51 for (;;) 52 ; 53 } 54} 55 56/* 57 * Defined in order to reuse memcpy() and memset() from 58 * arch/x86/boot/compressed/string.c 59 */ 60void warn(const char *msg) {} 61