// SPDX-License-Identifier: GPL-2.0-only
/*
 * purgatory: Runs between two kernels
 *
 * Copyright (C) 2014 Red Hat Inc.
 *
 * Author:
 *       Vivek Goyal <vgoyal@redhat.com>
 */

#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <crypto/sha2.h>
#include <asm/purgatory.h>

#include "../boot/compressed/error.h"
#include "../boot/string.h"

u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory");

struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory");

static 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;
}

void purgatory(void)
{
        int ret;

        ret = verify_sha256_digest();
        if (ret) {
                /* loop forever */
                for (;;)
                        ;
        }
}

/*
 * Defined in order to reuse memcpy() and memset() from
 * arch/x86/boot/compressed/string.c
 */
void warn(const char *msg) {}