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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lz4_wrapper.c (2957B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Copyright (c) 2013, 2014
      4 * Phillip Lougher <phillip@squashfs.org.uk>
      5 */
      6
      7#include <linux/bio.h>
      8#include <linux/mutex.h>
      9#include <linux/slab.h>
     10#include <linux/vmalloc.h>
     11#include <linux/lz4.h>
     12
     13#include "squashfs_fs.h"
     14#include "squashfs_fs_sb.h"
     15#include "squashfs.h"
     16#include "decompressor.h"
     17#include "page_actor.h"
     18
     19#define LZ4_LEGACY	1
     20
     21struct lz4_comp_opts {
     22	__le32 version;
     23	__le32 flags;
     24};
     25
     26struct squashfs_lz4 {
     27	void *input;
     28	void *output;
     29};
     30
     31
     32static void *lz4_comp_opts(struct squashfs_sb_info *msblk,
     33	void *buff, int len)
     34{
     35	struct lz4_comp_opts *comp_opts = buff;
     36
     37	/* LZ4 compressed filesystems always have compression options */
     38	if (comp_opts == NULL || len < sizeof(*comp_opts))
     39		return ERR_PTR(-EIO);
     40
     41	if (le32_to_cpu(comp_opts->version) != LZ4_LEGACY) {
     42		/* LZ4 format currently used by the kernel is the 'legacy'
     43		 * format */
     44		ERROR("Unknown LZ4 version\n");
     45		return ERR_PTR(-EINVAL);
     46	}
     47
     48	return NULL;
     49}
     50
     51
     52static void *lz4_init(struct squashfs_sb_info *msblk, void *buff)
     53{
     54	int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
     55	struct squashfs_lz4 *stream;
     56
     57	stream = kzalloc(sizeof(*stream), GFP_KERNEL);
     58	if (stream == NULL)
     59		goto failed;
     60	stream->input = vmalloc(block_size);
     61	if (stream->input == NULL)
     62		goto failed2;
     63	stream->output = vmalloc(block_size);
     64	if (stream->output == NULL)
     65		goto failed3;
     66
     67	return stream;
     68
     69failed3:
     70	vfree(stream->input);
     71failed2:
     72	kfree(stream);
     73failed:
     74	ERROR("Failed to initialise LZ4 decompressor\n");
     75	return ERR_PTR(-ENOMEM);
     76}
     77
     78
     79static void lz4_free(void *strm)
     80{
     81	struct squashfs_lz4 *stream = strm;
     82
     83	if (stream) {
     84		vfree(stream->input);
     85		vfree(stream->output);
     86	}
     87	kfree(stream);
     88}
     89
     90
     91static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm,
     92	struct bio *bio, int offset, int length,
     93	struct squashfs_page_actor *output)
     94{
     95	struct bvec_iter_all iter_all = {};
     96	struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
     97	struct squashfs_lz4 *stream = strm;
     98	void *buff = stream->input, *data;
     99	int bytes = length, res;
    100
    101	while (bio_next_segment(bio, &iter_all)) {
    102		int avail = min(bytes, ((int)bvec->bv_len) - offset);
    103
    104		data = bvec_virt(bvec);
    105		memcpy(buff, data + offset, avail);
    106		buff += avail;
    107		bytes -= avail;
    108		offset = 0;
    109	}
    110
    111	res = LZ4_decompress_safe(stream->input, stream->output,
    112		length, output->length);
    113
    114	if (res < 0)
    115		return -EIO;
    116
    117	bytes = res;
    118	data = squashfs_first_page(output);
    119	buff = stream->output;
    120	while (data) {
    121		if (bytes <= PAGE_SIZE) {
    122			memcpy(data, buff, bytes);
    123			break;
    124		}
    125		memcpy(data, buff, PAGE_SIZE);
    126		buff += PAGE_SIZE;
    127		bytes -= PAGE_SIZE;
    128		data = squashfs_next_page(output);
    129	}
    130	squashfs_finish_page(output);
    131
    132	return res;
    133}
    134
    135const struct squashfs_decompressor squashfs_lz4_comp_ops = {
    136	.init = lz4_init,
    137	.comp_opts = lz4_comp_opts,
    138	.free = lz4_free,
    139	.decompress = lz4_uncompress,
    140	.id = LZ4_COMPRESSION,
    141	.name = "lz4",
    142	.supported = 1
    143};