coreboot/src/lib/lzma.c
Julius Werner 09f2921b5d cbfs: Add LZ4 in-place decompression support for pre-RAM stages
This patch ports the LZ4 decompression code that debuted in libpayload
last year to coreboot for use in CBFS stages (upgrading the base
algorithm to LZ4's dev branch to access the new in-place decompression
checks). This is especially useful for pre-RAM stages in constrained
SRAM-based systems, which previously could not be compressed due to
the size requirements of the LZMA scratchpad and bounce buffer. The
LZ4 algorithm offers a very lean decompressor function and in-place
decompression support to achieve roughly the same boot speed gains
(trading compression ratio for decompression time) with nearly no
memory overhead.

For now we only activate it for the stages that had previously not been
compressed at all on non-XIP (read: non-x86) boards. In the future we
may also consider replacing LZMA completely for certain boards, since
which algorithm wins out on boot speed depends on board-specific
parameters (architecture, processor speed, SPI transfer rate, etc.).

BRANCH=None
BUG=None
TEST=Built and booted Oak, Jerry, Nyan and Falco. Measured boot time on
Oak to be about ~20ms faster (cutting load times for affected stages
almost in half).

Change-Id: Iec256c0e6d585d1b69985461939884a54e3ab900
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/13638
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2016-02-22 21:38:37 +01:00

62 lines
1.9 KiB
C

/*
* coreboot interface to memory-saving variant of LZMA decoder
*
* Copyright (C) 2006 Carl-Daniel Hailfinger
* Released under the GNU GPL v2 or later
*
* Parts of this file are based on C/7zip/Compress/LZMA_C/LzmaTest.c from the LZMA
* SDK 4.42, which is written and distributed to public domain by Igor Pavlov.
*
*/
#include <console/console.h>
#include <string.h>
#include <lib.h>
#include <timestamp.h>
#include "lzmadecode.h"
size_t ulzman(const void *src, size_t srcn, void *dst, size_t dstn)
{
unsigned char properties[LZMA_PROPERTIES_SIZE];
const int data_offset = LZMA_PROPERTIES_SIZE + 8;
UInt32 outSize;
SizeT inProcessed;
SizeT outProcessed;
int res;
CLzmaDecoderState state;
SizeT mallocneeds;
MAYBE_STATIC unsigned char scratchpad[15980];
const unsigned char *cp;
memcpy(properties, src, LZMA_PROPERTIES_SIZE);
/* The outSize in LZMA stream is a 64bit integer stored in little-endian
* (ref: lzma.cc@LZMACompress: put_64). To prevent accessing by
* unaligned memory address and to load in correct endianness, read each
* byte and re-construct. */
cp = src + LZMA_PROPERTIES_SIZE;
outSize = cp[3] << 24 | cp[2] << 16 | cp[1] << 8 | cp[0];
if (LzmaDecodeProperties(&state.Properties, properties,
LZMA_PROPERTIES_SIZE) != LZMA_RESULT_OK) {
printk(BIOS_WARNING, "lzma: Incorrect stream properties.\n");
return 0;
}
mallocneeds = (LzmaGetNumProbs(&state.Properties) * sizeof(CProb));
if (mallocneeds > 15980) {
printk(BIOS_WARNING, "lzma: Decoder scratchpad too small!\n");
return 0;
}
state.Probs = (CProb *)scratchpad;
res = LzmaDecode(&state, src + data_offset, srcn - data_offset,
&inProcessed, dst, outSize, &outProcessed);
if (res != 0) {
printk(BIOS_WARNING, "lzma: Decoding error = %d\n", res);
return 0;
}
return outProcessed;
}
size_t ulzma(const void *src, void *dst)
{
return ulzman(src, ~(size_t)0, dst, ~(size_t)0);
}