1 // SPDX-License-Identifier: GPL-2.0-only
3 * purgatory: Runs between two kernels
5 * Copyright (C) 2014 Red Hat Inc.
8 * Vivek Goyal <vgoyal@redhat.com>
11 #include <linux/bug.h>
12 #include <linux/sha256.h>
13 #include <asm/purgatory.h>
15 #include "../boot/string.h"
17 unsigned long purgatory_backup_dest __section(.kexec-purgatory);
18 unsigned long purgatory_backup_src __section(.kexec-purgatory);
19 unsigned long purgatory_backup_sz __section(.kexec-purgatory);
21 u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(.kexec-purgatory);
23 struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(.kexec-purgatory);
26 * On x86, second kernel requries first 640K of memory to boot. Copy
27 * first 640K to a backup region in reserved memory range so that second
28 * kernel can use first 640K.
30 static int copy_backup_region(void)
32 if (purgatory_backup_dest) {
33 memcpy((void *)purgatory_backup_dest,
34 (void *)purgatory_backup_src, purgatory_backup_sz);
39 static int verify_sha256_digest(void)
41 struct kexec_sha_region *ptr, *end;
42 u8 digest[SHA256_DIGEST_SIZE];
43 struct sha256_state sctx;
46 end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);
48 for (ptr = purgatory_sha_regions; ptr < end; ptr++)
49 sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
51 sha256_final(&sctx, digest);
53 if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)))
63 ret = verify_sha256_digest();