09f2921b5d
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> |
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| .. | ||
| LICENSE | ||
| Makefile | ||
| README.md | ||
| liblz4.pc.in | ||
| lz4.c | ||
| lz4.h | ||
| lz4frame.c | ||
| lz4frame.h | ||
| lz4frame_static.h | ||
| lz4hc.c | ||
| lz4hc.h | ||
| xxhash.c | ||
| xxhash.h | ||
README.md
LZ4 - Library Files
The lib directory contains several files, but you don't necessarily need them all.
To integrate fast LZ4 compression/decompression into your program, you basically just need "lz4.c" and "lz4.h".
For more compression at the cost of compression speed (while preserving decompression speed), use lz4hc on top of regular lz4. lz4hc only provides compression functions. It also needs lz4 to compile properly.
If you want to produce files or data streams compatible with lz4 command line utility, use lz4frame. This library encapsulates lz4-compressed blocks into the official interoperable frame format. In order to work properly, lz4frame needs lz4 and lz4hc, and also xxhash, which provides error detection algorithm.
(Advanced stuff : It's possible to hide xxhash symbols into a local namespace. This is what liblz4 does, to avoid symbol duplication in case a user program would link to several libraries containing xxhash symbols.)
A more complex "lz4frame_static.h" is also provided, although its usage is not recommended. It contains definitions which are not guaranteed to remain stable within future versions. Use for static linking only.
The other files are not source code. There are :
- LICENSE : contains the BSD license text
- Makefile : script to compile or install lz4 library (static or dynamic)
- liblz4.pc.in : for pkg-config (make install)