cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

ihex.h (2206B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2/*
      3 * Compact binary representation of ihex records. Some devices need their
      4 * firmware loaded in strange orders rather than a single big blob, but
      5 * actually parsing ihex-as-text within the kernel seems silly. Thus,...
      6 */
      7
      8#ifndef __LINUX_IHEX_H__
      9#define __LINUX_IHEX_H__
     10
     11#include <linux/types.h>
     12#include <linux/firmware.h>
     13#include <linux/device.h>
     14
     15/* Intel HEX files actually limit the length to 256 bytes, but we have
     16   drivers which would benefit from using separate records which are
     17   longer than that, so we extend to 16 bits of length */
     18struct ihex_binrec {
     19	__be32 addr;
     20	__be16 len;
     21	uint8_t data[];
     22} __attribute__((packed));
     23
     24static inline uint16_t ihex_binrec_size(const struct ihex_binrec *p)
     25{
     26	return be16_to_cpu(p->len) + sizeof(*p);
     27}
     28
     29/* Find the next record, taking into account the 4-byte alignment */
     30static inline const struct ihex_binrec *
     31__ihex_next_binrec(const struct ihex_binrec *rec)
     32{
     33	const void *p = rec;
     34
     35	return p + ALIGN(ihex_binrec_size(rec), 4);
     36}
     37
     38static inline const struct ihex_binrec *
     39ihex_next_binrec(const struct ihex_binrec *rec)
     40{
     41	rec = __ihex_next_binrec(rec);
     42
     43	return be16_to_cpu(rec->len) ? rec : NULL;
     44}
     45
     46/* Check that ihex_next_binrec() won't take us off the end of the image... */
     47static inline int ihex_validate_fw(const struct firmware *fw)
     48{
     49	const struct ihex_binrec *end, *rec;
     50
     51	rec = (const void *)fw->data;
     52	end = (const void *)&fw->data[fw->size - sizeof(*end)];
     53
     54	for (; rec <= end; rec = __ihex_next_binrec(rec)) {
     55		/* Zero length marks end of records */
     56		if (rec == end && !be16_to_cpu(rec->len))
     57			return 0;
     58	}
     59	return -EINVAL;
     60}
     61
     62/* Request firmware and validate it so that we can trust we won't
     63 * run off the end while reading records... */
     64static inline int request_ihex_firmware(const struct firmware **fw,
     65					const char *fw_name,
     66					struct device *dev)
     67{
     68	const struct firmware *lfw;
     69	int ret;
     70
     71	ret = request_firmware(&lfw, fw_name, dev);
     72	if (ret)
     73		return ret;
     74	ret = ihex_validate_fw(lfw);
     75	if (ret) {
     76		dev_err(dev, "Firmware \"%s\" not valid IHEX records\n",
     77			fw_name);
     78		release_firmware(lfw);
     79		return ret;
     80	}
     81	*fw = lfw;
     82	return 0;
     83}
     84#endif /* __LINUX_IHEX_H__ */