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| author | Nick Terrell <terrelln@fb.com> | 2020-07-30 21:08:39 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-07-31 11:49:09 +0200 |
| commit | fb46d057db824693994b048d3a8c869892afaa3f (patch) | |
| tree | 09d43e27af366f91b5845de5fa02ec58b52e5b55 /Documentation/x86 | |
| parent | x86: Bump ZO_z_extra_bytes margin for zstd (diff) | |
| download | linux-fb46d057db824693994b048d3a8c869892afaa3f.tar.xz linux-fb46d057db824693994b048d3a8c869892afaa3f.zip | |
x86: Add support for ZSTD compressed kernel
- Add support for zstd compressed kernel
- Define __DISABLE_EXPORTS in Makefile
- Remove __DISABLE_EXPORTS definition from kaslr.c
- Bump the heap size for zstd.
- Update the documentation.
Integrates the ZSTD decompression code to the x86 pre-boot code.
Zstandard requires slightly more memory during the kernel decompression
on x86 (192 KB vs 64 KB), and the memory usage is independent of the
window size.
__DISABLE_EXPORTS is now defined in the Makefile, which covers both
the existing use in kaslr.c, and the use needed by the zstd decompressor
in misc.c.
This patch has been boot tested with both a zstd and gzip compressed
kernel on i386 and x86_64 using buildroot and QEMU.
Additionally, this has been tested in production on x86_64 devices.
We saw a 2 second boot time reduction by switching kernel compression
from xz to zstd.
Signed-off-by: Nick Terrell <terrelln@fb.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200730190841.2071656-7-nickrterrell@gmail.com
Diffstat (limited to 'Documentation/x86')
| -rw-r--r-- | Documentation/x86/boot.rst | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/Documentation/x86/boot.rst b/Documentation/x86/boot.rst index 5325c71ca877..7fafc7ac00d7 100644 --- a/Documentation/x86/boot.rst +++ b/Documentation/x86/boot.rst @@ -782,9 +782,9 @@ Protocol: 2.08+ uncompressed data should be determined using the standard magic numbers. The currently supported compression formats are gzip (magic numbers 1F 8B or 1F 9E), bzip2 (magic number 42 5A), LZMA - (magic number 5D 00), XZ (magic number FD 37), and LZ4 (magic number - 02 21). The uncompressed payload is currently always ELF (magic - number 7F 45 4C 46). + (magic number 5D 00), XZ (magic number FD 37), LZ4 (magic number + 02 21) and ZSTD (magic number 28 B5). The uncompressed payload is + currently always ELF (magic number 7F 45 4C 46). ============ ============== Field name: payload_length |