LXR linux/arch/s390/purgatory/purgatory.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Purgatory code running between two kernels.
   4 *
   5 * Copyright IBM Corp. 2018
   6 *
   7 * Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com>
   8 */
   9
  10#include <linux/kexec.h>
  11#include <linux/sha256.h>
  12#include <linux/string.h>
  13#include <asm/purgatory.h>
  14
  15struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX];
  16u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE];
  17
  18u64 kernel_entry;
  19u64 kernel_type;
  20
  21u64 crash_start;
  22u64 crash_size;
  23
  24int 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