/*
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* purgatory: Runs between two kernels
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*
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* Copyright (C) 2014 Red Hat Inc.
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*
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* Author:
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* Vivek Goyal <vgoyal@redhat.com>
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include "sha256.h"
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#include "../boot/string.h"
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struct sha_region {
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unsigned long start;
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unsigned long len;
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};
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unsigned long backup_dest = 0;
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unsigned long backup_src = 0;
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unsigned long backup_sz = 0;
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u8 sha256_digest[SHA256_DIGEST_SIZE] = { 0 };
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struct sha_region sha_regions[16] = {};
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/*
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* On x86, second kernel requries first 640K of memory to boot. Copy
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* first 640K to a backup region in reserved memory range so that second
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* kernel can use first 640K.
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*/
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static int copy_backup_region(void)
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{
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if (backup_dest)
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memcpy((void *)backup_dest, (void *)backup_src, backup_sz);
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return 0;
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}
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int verify_sha256_digest(void)
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{
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struct sha_region *ptr, *end;
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u8 digest[SHA256_DIGEST_SIZE];
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struct sha256_state sctx;
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sha256_init(&sctx);
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end = &sha_regions[sizeof(sha_regions)/sizeof(sha_regions[0])];
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for (ptr = sha_regions; ptr < end; ptr++)
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sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
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sha256_final(&sctx, digest);
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if (memcmp(digest, sha256_digest, sizeof(digest)))
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return 1;
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return 0;
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}
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void purgatory(void)
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{
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int ret;
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ret = verify_sha256_digest();
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if (ret) {
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/* loop forever */
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for (;;)
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;
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}
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copy_backup_region();
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}
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