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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uncompress.c (1807B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * uncompress.c
      4 *
      5 * (C) Copyright 1999 Linus Torvalds
      6 *
      7 * cramfs interfaces to the uncompression library. There's really just
      8 * three entrypoints:
      9 *
     10 *  - cramfs_uncompress_init() - called to initialize the thing.
     11 *  - cramfs_uncompress_exit() - tell me when you're done
     12 *  - cramfs_uncompress_block() - uncompress a block.
     13 *
     14 * NOTE NOTE NOTE! The uncompression is entirely single-threaded. We
     15 * only have one stream, and we'll initialize it only once even if it
     16 * then is used by multiple filesystems.
     17 */
     18
     19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
     20
     21#include <linux/kernel.h>
     22#include <linux/errno.h>
     23#include <linux/vmalloc.h>
     24#include <linux/zlib.h>
     25#include "internal.h"
     26
     27static z_stream stream;
     28static int initialized;
     29
     30/* Returns length of decompressed data. */
     31int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen)
     32{
     33	int err;
     34
     35	stream.next_in = src;
     36	stream.avail_in = srclen;
     37
     38	stream.next_out = dst;
     39	stream.avail_out = dstlen;
     40
     41	err = zlib_inflateReset(&stream);
     42	if (err != Z_OK) {
     43		pr_err("zlib_inflateReset error %d\n", err);
     44		zlib_inflateEnd(&stream);
     45		zlib_inflateInit(&stream);
     46	}
     47
     48	err = zlib_inflate(&stream, Z_FINISH);
     49	if (err != Z_STREAM_END)
     50		goto err;
     51	return stream.total_out;
     52
     53err:
     54	pr_err("Error %d while decompressing!\n", err);
     55	pr_err("%p(%d)->%p(%d)\n", src, srclen, dst, dstlen);
     56	return -EIO;
     57}
     58
     59int cramfs_uncompress_init(void)
     60{
     61	if (!initialized++) {
     62		stream.workspace = vmalloc(zlib_inflate_workspacesize());
     63		if (!stream.workspace) {
     64			initialized = 0;
     65			return -ENOMEM;
     66		}
     67		stream.next_in = NULL;
     68		stream.avail_in = 0;
     69		zlib_inflateInit(&stream);
     70	}
     71	return 0;
     72}
     73
     74void cramfs_uncompress_exit(void)
     75{
     76	if (!--initialized) {
     77		zlib_inflateEnd(&stream);
     78		vfree(stream.workspace);
     79	}
     80}