Messages in this thread Patch in this message | | | From | Nick Terrell <> | Subject | [PATCH v5 4/8] init: add support for zstd compressed kernel | Date | Wed, 8 Apr 2020 14:57:07 -0700 |
| |
From: Nick Terrell <terrelln@fb.com>
* Adds the zstd cmd to scripts/Makefile.lib * Adds the HAVE_KERNEL_ZSTD and KERNEL_ZSTD options
Architecture specific support is still needed for decompression.
Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Nick Terrell <terrelln@fb.com> --- init/Kconfig | 15 ++++++++++++++- scripts/Makefile.lib | 15 +++++++++++++++ 2 files changed, 29 insertions(+), 1 deletion(-)
diff --git a/init/Kconfig b/init/Kconfig index 492bb7000aa4..806874fdd663 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -176,13 +176,16 @@ config HAVE_KERNEL_LZO config HAVE_KERNEL_LZ4 bool +config HAVE_KERNEL_ZSTD + bool + config HAVE_KERNEL_UNCOMPRESSED bool choice prompt "Kernel compression mode" default KERNEL_GZIP - depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 || HAVE_KERNEL_UNCOMPRESSED + depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA || HAVE_KERNEL_XZ || HAVE_KERNEL_LZO || HAVE_KERNEL_LZ4 || HAVE_KERNEL_ZSTD || HAVE_KERNEL_UNCOMPRESSED help The linux kernel is a kind of self-extracting executable. Several compression algorithms are available, which differ @@ -261,6 +264,16 @@ config KERNEL_LZ4 is about 8% bigger than LZO. But the decompression speed is faster than LZO. +config KERNEL_ZSTD + bool "ZSTD" + depends on HAVE_KERNEL_ZSTD + help + ZSTD is a compression algorithm targeting intermediate compression + with fast decompression speed. It will compress better than GZIP and + decompress around the same speed as LZO, but slower than LZ4. You + will need at least 192 KB RAM or more for booting. The zstd command + line tools is required for compression. + config KERNEL_UNCOMPRESSED bool "None" depends on HAVE_KERNEL_UNCOMPRESSED diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index b12dd5ba4896..efe69b78d455 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -405,6 +405,21 @@ 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. + +quiet_cmd_zstd = ZSTD $@ +cmd_zstd = (cat $(filter-out FORCE,$^) | \ + zstd -19 && \ + $(call size_append, $(filter-out FORCE,$^))) > $@ || \ + (rm -f $@ ; false) + # ASM offsets # --------------------------------------------------------------------------- -- 2.26.0
| |