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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-03 16:03:23 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-03 16:03:23 -0700 |
| commit | c0dfadfed87489fa6126ece161a14c2d15dbdc79 (patch) | |
| tree | 2b1ac3fb464e4d18b57e3d4735cd6b60454cc972 /scripts/Makefile.lib | |
| parent | ba77c568f3160657a5f7905289c07d18c2dfde78 (diff) | |
| parent | 1ac1efa5f6950f8f126f2c1921bb699ce009ec7d (diff) | |
| download | linux-c0dfadfed87489fa6126ece161a14c2d15dbdc79.tar.bz2 | |
Merge tag 'x86-boot-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Ingo Molnar:
"The main change in this cycle was to add support for ZSTD-compressed
kernel and initrd images.
ZSTD has a very fast decompressor, yet it compresses better than gzip"
* tag 'x86-boot-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Documentation: dontdiff: Add zstd compressed files
.gitignore: Add ZSTD-compressed files
x86: Add support for ZSTD compressed kernel
x86: Bump ZO_z_extra_bytes margin for zstd
usr: Add support for zstd compressed initramfs
init: Add support for zstd compressed kernel
lib: Add zstd support to decompress
lib: Prepare zstd for preboot environment, improve performance
Diffstat (limited to 'scripts/Makefile.lib')
| -rw-r--r-- | scripts/Makefile.lib | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 916b2f7f7098..54f7b7eb580b 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -413,6 +413,28 @@ quiet_cmd_xzkern = XZKERN $@ quiet_cmd_xzmisc = XZMISC $@ cmd_xzmisc = cat $(real-prereqs) | $(XZ) --check=crc32 --lzma2=dict=1MiB > $@ +# ZSTD +# --------------------------------------------------------------------------- +# Appends the uncompressed size of the data using size_append. The .zst +# format has the size information available at the beginning of the file too, +# but it's in a more complex format and it's good to avoid changing the part +# of the boot code that reads the uncompressed size. +# +# Note that the bytes added by size_append will make the zstd tool think that +# the file is corrupt. This is expected. +# +# zstd uses a maximum window size of 8 MB. zstd22 uses a maximum window size of +# 128 MB. zstd22 is used for kernel compression because it is decompressed in a +# single pass, so zstd doesn't need to allocate a window buffer. When streaming +# decompression is used, like initramfs decompression, zstd22 should likely not +# be used because it would require zstd to allocate a 128 MB buffer. + +quiet_cmd_zstd = ZSTD $@ + cmd_zstd = { cat $(real-prereqs) | $(ZSTD) -19; $(size_append); } > $@ + +quiet_cmd_zstd22 = ZSTD22 $@ + cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) -22 --ultra; $(size_append); } > $@ + # ASM offsets # --------------------------------------------------------------------------- |