linux/init
Lasse Collin 7472ff8ada xz: adjust arch-specific options for better kernel compression
Use LZMA2 options that match the arch-specific alignment of instructions. 
This change reduces compressed kernel size 0-2 % depending on the arch. 
On 1-byte-aligned x86 it makes no difference and on 4-byte-aligned archs
it helps the most.

Use the ARM-Thumb filter for ARM-Thumb2 kernels.  This reduces compressed
kernel size about 5 %.[1] Previously such kernels were compressed using
the ARM filter which didn't do anything useful with ARM-Thumb2 code.

Add BCJ filter support for ARM64 and RISC-V.  Compared to unfiltered XZ or
plain LZMA, the compressed kernel size is reduced about 5 % on ARM64 and 7
% on RISC-V.  A new enough version of the xz tool is required: 5.4.0 for
ARM64 and 5.6.0 for RISC-V.  With an old xz version, a message is printed
to standard error and the kernel is compressed without the filter.

Update lib/decompress_unxz.c to match the changes to xz_wrap.sh.

Update the CONFIG_KERNEL_XZ help text in init/Kconfig:
  - Add the RISC-V and ARM64 filters.
  - Clarify that the PowerPC filter is for big endian only.
  - Omit IA-64.

Link: https://lore.kernel.org/lkml/1637379771-39449-1-git-send-email-zhongjubin@huawei.com/ [1]
Link: https://lkml.kernel.org/r/20240721133633.47721-15-lasse.collin@tukaani.org
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Reviewed-by: Sam James <sam@gentoo.org>
Cc: Simon Glass <sjg@chromium.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Jubin Zhong <zhongjubin@huawei.com>
Cc: Jules Maselbas <jmaselbas@zdiv.net>
Cc: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rui Li <me@lirui.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:43:27 -07:00
..
.gitignore kbuild: build init/built-in.a just once 2022-09-29 04:40:15 +09:00
calibrate.c
do_mounts_initrd.c initrd: remove the now superfluous sentinel element from ctl_table array 2024-04-25 21:07:05 -07:00
do_mounts_rd.c
do_mounts.c init: replace deprecated strncpy with strscpy_pad 2024-04-30 10:34:29 -07:00
do_mounts.h init: flush async file closing 2024-02-08 18:41:03 +01:00
init_task.c Livepatching changes for 6.10 2024-05-15 13:07:49 -07:00
initramfs.c Merge 6.9-rc5 into driver-core-next 2024-04-23 13:27:43 +02:00
Kconfig xz: adjust arch-specific options for better kernel compression 2024-09-01 20:43:27 -07:00
main.c Mainly singleton patches, documented in their respective changelogs. 2024-05-19 14:02:03 -07:00
Makefile kbuild: move init/build-version to scripts/ 2024-07-16 01:08:37 +09:00
noinitramfs.c init: move usermodehelper_enable() to populate_rootfs() 2021-09-08 11:50:27 -07:00
version-timestamp.c init/version-timestamp.c: remove unneeded #include <linux/version.h> 2023-01-09 07:34:38 +09:00
version.c init/version.c: Replace strlcpy with strscpy 2023-09-22 09:50:56 -07:00