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