1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * purgatory: Runs between two kernels
4 *
5 * Copyright (C) 2022 Huawei Technologies Co, Ltd.
6 *
7 * Author: Li Zhengyu (lizhengyu3@huawei.com)
8 *
9 */
10
11 #include <linux/purgatory.h>
12 #include <linux/kernel.h>
13 #include <linux/string.h>
14 #include <asm/string.h>
15
16 u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory");
17
18 struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory");
19
20 static int verify_sha256_digest(void)
21 {
22 struct kexec_sha_region *ptr, *end;
23 struct sha256_state ss;
24 u8 digest[SHA256_DIGEST_SIZE];
25
26 sha256_init(&ss);
27 end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);
28 for (ptr = purgatory_sha_regions; ptr < end; ptr++)
29 sha256_update(&ss, (uint8_t *)(ptr->start), ptr->len);
30 sha256_final(&ss, digest);
31 if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)) != 0)
32 return 1;
33 return 0;
34 }
35
36 /* workaround for a warning with -Wmissing-prototypes */
37 void purgatory(void);
38
39 void purgatory(void)
40 {
41 if (verify_sha256_digest())
42 for (;;)
43 /* loop forever */
44 ;
45 }
46
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