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Code Issues Releases Wiki Activity

Fix erasing of unaligned regions

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The erase (-E) feature is somehow a brute force method, but still, if we
are given a region to erase, we should make sure to restore surrounding
data if the erase block expands beyond the region.

Slight alteration from `master` commit: Guard free() from NULL pointers
to be regression safe even in case of broken libc.

Change-Id: I5fc35310f0b090f218cd1d660e27fb39dd05c3c5
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/c/31069
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
This commit is contained in:
Nico Huber 2019-01-23 17:07:49 +01:00 committed by Nico Huber
parent 69f96f6029
commit a3db7ed513
1 changed files with 68 additions and 3 deletions
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71
flashrom.c
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@ -1690,17 +1690,82 @@ static int erase_block(struct flashctx *const flashctx,
const struct walk_info *const info, const erasefn_t erasefn) const struct walk_info *const info, const erasefn_t erasefn)
{ {
const unsigned int erase_len = info->erase_end + 1 - info->erase_start; const unsigned int erase_len = info->erase_end + 1 - info->erase_start;
const bool region_unaligned = info->region_start > info->erase_start ||
info->erase_end > info->region_end;
uint8_t *backup_contents = NULL, *erased_contents = NULL;
int ret = 2;
/*
* If the region is not erase-block aligned, merge current flash con-
* tents into a new buffer `backup_contents`.
*/
if (region_unaligned) {
backup_contents = malloc(erase_len);
erased_contents = malloc(erase_len);
if (!backup_contents || !erased_contents) {
msg_cerr("Out of memory!\n");
ret = 1;
goto _free_ret;
}
memset(backup_contents, 0xff, erase_len);
memset(erased_contents, 0xff, erase_len);
msg_cdbg("R");
/* Merge data preceding the current region. */
if (info->region_start > info->erase_start) {
const chipoff_t start = info->erase_start;
const chipsize_t len = info->region_start - info->erase_start;
if (flashctx->chip->read(flashctx, backup_contents, start, len)) {
msg_cerr("Can't read! Aborting.\n");
goto _free_ret;
}
}
/* Merge data following the current region. */
if (info->erase_end > info->region_end) {
const chipoff_t start = info->region_end + 1;
const chipoff_t rel_start = start - info->erase_start; /* within this erase block */
const chipsize_t len = info->erase_end - info->region_end;
if (flashctx->chip->read(flashctx, backup_contents + rel_start, start, len)) {
msg_cerr("Can't read! Aborting.\n");
goto _free_ret;
}
}
}
ret = 1;
all_skipped = false; all_skipped = false;
msg_cdbg("E"); msg_cdbg("E");
if (erasefn(flashctx, info->erase_start, erase_len)) if (erasefn(flashctx, info->erase_start, erase_len))
return 1; goto _free_ret;
if (check_erased_range(flashctx, info->erase_start, erase_len)) { if (check_erased_range(flashctx, info->erase_start, erase_len)) {
msg_cerr("ERASE FAILED!\n"); msg_cerr("ERASE FAILED!\n");
return 1; goto _free_ret;
} }
return 0;
if (region_unaligned) {
unsigned int starthere = 0, lenhere = 0, writecount = 0;
/* get_next_write() sets starthere to a new value after the call. */
while ((lenhere = get_next_write(erased_contents + starthere, backup_contents + starthere,
erase_len - starthere, &starthere, flashctx->chip->gran))) {
if (!writecount++)
msg_cdbg("W");
/* Needs the partial write function signature. */
if (flashctx->chip->write(flashctx, backup_contents + starthere,
info->erase_start + starthere, lenhere))
goto _free_ret;
starthere += lenhere;
}
}
ret = 0;
_free_ret:
if (erased_contents != NULL)
free(erased_contents);
if (backup_contents != NULL)
free(backup_contents);
return ret;
} }
/** /**