cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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parser_trx.c (3124B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Parser for TRX format partitions
      4 *
      5 * Copyright (C) 2012 - 2017 Rafał Miłecki <rafal@milecki.pl>
      6 */
      7
      8#include <linux/module.h>
      9#include <linux/slab.h>
     10#include <linux/mtd/mtd.h>
     11#include <linux/mtd/partitions.h>
     12
     13#define TRX_PARSER_MAX_PARTS		4
     14
     15/* Magics */
     16#define TRX_MAGIC			0x30524448
     17#define UBI_EC_MAGIC			0x23494255	/* UBI# */
     18
     19struct trx_header {
     20	uint32_t magic;
     21	uint32_t length;
     22	uint32_t crc32;
     23	uint16_t flags;
     24	uint16_t version;
     25	uint32_t offset[3];
     26} __packed;
     27
     28static const char *parser_trx_data_part_name(struct mtd_info *master,
     29					     size_t offset)
     30{
     31	uint32_t buf;
     32	size_t bytes_read;
     33	int err;
     34
     35	err  = mtd_read(master, offset, sizeof(buf), &bytes_read,
     36			(uint8_t *)&buf);
     37	if (err && !mtd_is_bitflip(err)) {
     38		pr_err("mtd_read error while parsing (offset: 0x%zX): %d\n",
     39			offset, err);
     40		goto out_default;
     41	}
     42
     43	if (buf == UBI_EC_MAGIC)
     44		return "ubi";
     45
     46out_default:
     47	return "rootfs";
     48}
     49
     50static int parser_trx_parse(struct mtd_info *mtd,
     51			    const struct mtd_partition **pparts,
     52			    struct mtd_part_parser_data *data)
     53{
     54	struct device_node *np = mtd_get_of_node(mtd);
     55	struct mtd_partition *parts;
     56	struct mtd_partition *part;
     57	struct trx_header trx;
     58	size_t bytes_read;
     59	uint8_t curr_part = 0, i = 0;
     60	uint32_t trx_magic = TRX_MAGIC;
     61	int err;
     62
     63	/* Get different magic from device tree if specified */
     64	err = of_property_read_u32(np, "brcm,trx-magic", &trx_magic);
     65	if (err != 0 && err != -EINVAL)
     66		pr_err("failed to parse \"brcm,trx-magic\" DT attribute, using default: %d\n", err);
     67
     68	parts = kcalloc(TRX_PARSER_MAX_PARTS, sizeof(struct mtd_partition),
     69			GFP_KERNEL);
     70	if (!parts)
     71		return -ENOMEM;
     72
     73	err = mtd_read(mtd, 0, sizeof(trx), &bytes_read, (uint8_t *)&trx);
     74	if (err) {
     75		pr_err("MTD reading error: %d\n", err);
     76		kfree(parts);
     77		return err;
     78	}
     79
     80	if (trx.magic != trx_magic) {
     81		kfree(parts);
     82		return -ENOENT;
     83	}
     84
     85	/* We have LZMA loader if there is address in offset[2] */
     86	if (trx.offset[2]) {
     87		part = &parts[curr_part++];
     88		part->name = "loader";
     89		part->offset = trx.offset[i];
     90		i++;
     91	}
     92
     93	if (trx.offset[i]) {
     94		part = &parts[curr_part++];
     95		part->name = "linux";
     96		part->offset = trx.offset[i];
     97		i++;
     98	}
     99
    100	if (trx.offset[i]) {
    101		part = &parts[curr_part++];
    102		part->name = parser_trx_data_part_name(mtd, trx.offset[i]);
    103		part->offset = trx.offset[i];
    104		i++;
    105	}
    106
    107	/*
    108	 * Assume that every partition ends at the beginning of the one it is
    109	 * followed by.
    110	 */
    111	for (i = 0; i < curr_part; i++) {
    112		u64 next_part_offset = (i < curr_part - 1) ?
    113				       parts[i + 1].offset : mtd->size;
    114
    115		parts[i].size = next_part_offset - parts[i].offset;
    116	}
    117
    118	*pparts = parts;
    119	return i;
    120};
    121
    122static const struct of_device_id mtd_parser_trx_of_match_table[] = {
    123	{ .compatible = "brcm,trx" },
    124	{},
    125};
    126MODULE_DEVICE_TABLE(of, mtd_parser_trx_of_match_table);
    127
    128static struct mtd_part_parser mtd_parser_trx = {
    129	.parse_fn = parser_trx_parse,
    130	.name = "trx",
    131	.of_match_table = mtd_parser_trx_of_match_table,
    132};
    133module_mtd_part_parser(mtd_parser_trx);
    134
    135MODULE_LICENSE("GPL v2");
    136MODULE_DESCRIPTION("Parser for TRX format partitions");