cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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purgatory.c (733B)

      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/string.h>
     12#include <crypto/sha2.h>
     13#include <asm/purgatory.h>
     14
     15int verify_sha256_digest(void)
     16{
     17	struct kexec_sha_region *ptr, *end;
     18	u8 digest[SHA256_DIGEST_SIZE];
     19	struct sha256_state sctx;
     20
     21	sha256_init(&sctx);
     22	end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);
     23
     24	for (ptr = purgatory_sha_regions; ptr < end; ptr++)
     25		sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
     26
     27	sha256_final(&sctx, digest);
     28
     29	if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)))
     30		return 1;
     31
     32	return 0;
     33}