Function parse_cbtable

util/cbmem/devmem_drv.c:162–240

Return < 0 on error, 0 on success. */

/* Return < 0 on error, 0 on success. */
static int parse_cbtable(uint64_t address, size_t table_size)
{
	const uint8_t *buf;
	struct mapping header_mapping;
	size_t req_size;
	size_t i;

	req_size = table_size;
	/* Default to 4 KiB search space. */
	if (req_size == 0)
		req_size = 4 * 1024;

	debug("Looking for coreboot table at %" PRIx64 " %zd bytes.\n", address, req_size);

	buf = map_memory(&header_mapping, address, req_size);

	if (!buf)
		return -1;

	/* look at every 16 bytes */
	for (i = 0; i <= req_size - sizeof(struct lb_header); i += 16) {
		const struct lb_header *lbh;
		struct mapping table_mapping;

		lbh = (const struct lb_header *)&buf[i];
		if (memcmp(lbh->signature, "LBIO", sizeof(lbh->signature)) ||
		    !lbh->header_bytes || ipchksum(lbh, sizeof(*lbh))) {
			continue;
		}

		/* Map in the whole table to parse. */
		if (!map_memory(&table_mapping, address + i,
				lbh->header_bytes + lbh->table_bytes)) {
			debug("Couldn't map in table\n");
			continue;
		}

		const uint8_t *table_contents =
			&((uint8_t *)mapping_virt(&table_mapping))[lbh->header_bytes];
		if (ipchksum(table_contents, lbh->table_bytes) !=
		    lbh->table_checksum) {
			debug("Signature found, but wrong checksum.\n");
			unmap_memory(&table_mapping);
			continue;
		}

		debug("Found at %#" PRIx64 "\n", address + i);

		const struct lb_record *lbr_p;

		for (size_t offset = 0; offset < lbh->table_bytes; offset += lbr_p->size) {
			lbr_p = (const struct lb_record *)&table_contents[offset];
			debug("  coreboot table entry 0x%02x\n", lbr_p->tag);

			if (lbr_p->tag != LB_TAG_FORWARD)
				continue;

			/* This is a forwarding entry. Repeat the search at the new address. */