diff options
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 # --------------------------------------------------------------------------- |