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