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https://github.com/torvalds/linux
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a30d8a39f0
- Add support for a zstd compressed initramfs. - Add compression for compressing built-in initramfs with zstd. I have tested this patch by boot testing with buildroot and QEMU. Specifically, I booted the kernel with both a zstd and gzip compressed initramfs, both built into the kernel and separate. I ensured that the correct compression algorithm was used. I tested on arm, aarch64, i386, and x86_64. This patch has been tested in production on aarch64 and x86_64 devices. Additionally, I have performance measurements from internal use in production. On an aarch64 device we saw 19 second boot time improvement from switching from lzma to zstd (27 seconds to 8 seconds). On an x86_64 device we saw a 9 second boot time reduction from switching 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/20200730190841.2071656-5-nickrterrell@gmail.com
89 lines
2.9 KiB
Makefile
89 lines
2.9 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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#
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# kbuild file for usr/ - including initramfs image
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#
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# cmd_bzip2, cmd_lzma, cmd_lzo, cmd_lz4 from scripts/Makefile.lib appends the
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# size at the end of the compressed file, which unfortunately does not work
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# with unpack_to_rootfs(). Make size_append no-op.
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override size_append := :
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compress-y := shipped
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compress-$(CONFIG_INITRAMFS_COMPRESSION_GZIP) := gzip
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compress-$(CONFIG_INITRAMFS_COMPRESSION_BZIP2) := bzip2
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compress-$(CONFIG_INITRAMFS_COMPRESSION_LZMA) := lzma
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compress-$(CONFIG_INITRAMFS_COMPRESSION_XZ) := xzmisc
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compress-$(CONFIG_INITRAMFS_COMPRESSION_LZO) := lzo
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compress-$(CONFIG_INITRAMFS_COMPRESSION_LZ4) := lz4
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compress-$(CONFIG_INITRAMFS_COMPRESSION_ZSTD) := zstd
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obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data.o
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$(obj)/initramfs_data.o: $(obj)/initramfs_inc_data
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ramfs-input := $(strip $(shell echo $(CONFIG_INITRAMFS_SOURCE)))
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cpio-data :=
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# If CONFIG_INITRAMFS_SOURCE is empty, generate a small initramfs with the
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# default contents.
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ifeq ($(ramfs-input),)
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ramfs-input := $(srctree)/$(src)/default_cpio_list
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endif
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ifeq ($(words $(ramfs-input)),1)
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# If CONFIG_INITRAMFS_SOURCE specifies a single file, and it is suffixed with
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# .cpio, use it directly as an initramfs.
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ifneq ($(filter %.cpio,$(ramfs-input)),)
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cpio-data := $(ramfs-input)
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endif
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# If CONFIG_INITRAMFS_SOURCE specifies a single file, and it is suffixed with
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# .cpio.*, use it directly as an initramfs, and avoid double compression.
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ifeq ($(words $(subst .cpio.,$(space),$(ramfs-input))),2)
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cpio-data := $(ramfs-input)
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compress-y := shipped
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endif
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endif
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# For other cases, generate the initramfs cpio archive based on the contents
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# specified by CONFIG_INITRAMFS_SOURCE.
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ifeq ($(cpio-data),)
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cpio-data := $(obj)/initramfs_data.cpio
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hostprogs := gen_init_cpio
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# .initramfs_data.cpio.d is used to identify all files included
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# in initramfs and to detect if any files are added/removed.
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# Removed files are identified by directory timestamp being updated
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# The dependency list is generated by gen_initramfs.sh -l
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-include $(obj)/.initramfs_data.cpio.d
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# do not try to update files included in initramfs
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$(deps_initramfs): ;
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quiet_cmd_initfs = GEN $@
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cmd_initfs = \
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$(CONFIG_SHELL) $< -o $@ -l $(obj)/.initramfs_data.cpio.d \
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$(if $(CONFIG_INITRAMFS_ROOT_UID), -u $(CONFIG_INITRAMFS_ROOT_UID)) \
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$(if $(CONFIG_INITRAMFS_ROOT_GID), -g $(CONFIG_INITRAMFS_ROOT_GID)) \
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$(ramfs-input)
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# We rebuild initramfs_data.cpio if:
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# 1) Any included file is newer than initramfs_data.cpio
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# 2) There are changes in which files are included (added or deleted)
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# 3) If gen_init_cpio are newer than initramfs_data.cpio
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# 4) Arguments to gen_initramfs.sh changes
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$(obj)/initramfs_data.cpio: $(src)/gen_initramfs.sh $(obj)/gen_init_cpio $(deps_initramfs) FORCE
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$(call if_changed,initfs)
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endif
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$(obj)/initramfs_inc_data: $(cpio-data) FORCE
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$(call if_changed,$(compress-y))
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targets += initramfs_data.cpio initramfs_inc_data
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subdir-$(CONFIG_UAPI_HEADER_TEST) += include
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