// SPDX-License-Identifier: GPL-2.0
/*
 * Purgatory code running between two kernels.
 *
 * Copyright IBM Corp. 2018
 *
 * Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com>
 */

#include <linux/kexec.h>
#include <linux/string.h>
#include <crypto/sha2.h>
#include <asm/purgatory.h>

int verify_sha256_digest(void)
{
        struct kexec_sha_region *ptr, *end;
        u8 digest[SHA256_DIGEST_SIZE];
        struct sha256_ctx sctx;

        sha256_init(&sctx);
        end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);

        for (ptr = purgatory_sha_regions; ptr < end; ptr++)
                sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);

        sha256_final(&sctx, digest);

        if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)))
                return 1;

        return 0;
}