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git.kernel.org/linux-stable/master
linux-imx/usr/Makefile
Masahiro Yamada 7ce7e984ab kbuild: rename cmd_{bzip2,lzma,lzo,lz4,xzkern,zstd22} 
GZIP-compressed files end with 4 byte data that represents the size
of the original input. The decompressors (the self-extracting kernel)
exploit it to know the vmlinux size beforehand. To mimic the GZIP's
trailer, Kbuild provides cmd_{bzip2,lzma,lzo,lz4,xzkern,zstd22}.
Unfortunately these macros are used everywhere despite the appended
size data is only useful for the decompressors.

There is no guarantee that such hand-crafted trailers are safely ignored.
In fact, the kernel refuses compressed initramdfs with the garbage data.
That is why usr/Makefile overrides size_append to make it no-op.

To limit the use of such broken compressed files, this commit renames
the existing macros as follows:

  cmd_bzip2   --> cmd_bzip2_with_size
  cmd_lzma    --> cmd_lzma_with_size
  cmd_lzo     --> cmd_lzo_with_size
  cmd_lz4     --> cmd_lz4_with_size
  cmd_xzkern  --> cmd_xzkern_with_size
  cmd_zstd22  --> cmd_zstd22_with_size

To keep the decompressors working, I updated the following Makefiles
accordingly:

  arch/arm/boot/compressed/Makefile
  arch/h8300/boot/compressed/Makefile
  arch/mips/boot/compressed/Makefile
  arch/parisc/boot/compressed/Makefile
  arch/s390/boot/compressed/Makefile
  arch/sh/boot/compressed/Makefile
  arch/x86/boot/compressed/Makefile

I reused the current macro names for the normal usecases; they produce
the compressed data in the proper format.

I did not touch the following:

  arch/arc/boot/Makefile
  arch/arm64/boot/Makefile
  arch/csky/boot/Makefile
  arch/mips/boot/Makefile
  arch/riscv/boot/Makefile
  arch/sh/boot/Makefile
  kernel/Makefile

This means those Makefiles will stop appending the size data.

I dropped the 'override size_append' hack from usr/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
2022-01-14 02:54:05 +09:00

2.7 KiB
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SPDX-License-Identifier: GPL-2.0

kbuild file for usr/ - including initramfs image

compress-y := shipped compress-$(CONFIG_INITRAMFS_COMPRESSION_GZIP) := gzip compress-$(CONFIG_INITRAMFS_COMPRESSION_BZIP2) := bzip2 compress-$(CONFIG_INITRAMFS_COMPRESSION_LZMA) := lzma compress-$(CONFIG_INITRAMFS_COMPRESSION_XZ) := xzmisc compress-$(CONFIG_INITRAMFS_COMPRESSION_LZO) := lzo compress-$(CONFIG_INITRAMFS_COMPRESSION_LZ4) := lz4 compress-$(CONFIG_INITRAMFS_COMPRESSION_ZSTD) := zstd

obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data.o

$(obj)/initramfs_data.o: $(obj)/initramfs_inc_data

ramfs-input := $(CONFIG_INITRAMFS_SOURCE) cpio-data :=

If CONFIG_INITRAMFS_SOURCE is empty, generate a small initramfs with the

default contents.

ifeq ($(ramfs-input),) ramfs-input := $(srctree)/$(src)/default_cpio_list endif

ifeq ($(words $(ramfs-input)),1)

If CONFIG_INITRAMFS_SOURCE specifies a single file, and it is suffixed with

.cpio, use it directly as an initramfs.

ifneq ($(filter %.cpio,$(ramfs-input)),) cpio-data := $(ramfs-input) endif

If CONFIG_INITRAMFS_SOURCE specifies a single file, and it is suffixed with

.cpio.*, use it directly as an initramfs, and avoid double compression.

ifeq ($(words $(subst .cpio.,$(space),$(ramfs-input))),2) cpio-data := $(ramfs-input) compress-y := shipped endif

endif

For other cases, generate the initramfs cpio archive based on the contents

specified by CONFIG_INITRAMFS_SOURCE.

ifeq ($(cpio-data),)

cpio-data := $(obj)/initramfs_data.cpio

hostprogs := gen_init_cpio

.initramfs_data.cpio.d is used to identify all files included

in initramfs and to detect if any files are added/removed.

Removed files are identified by directory timestamp being updated

The dependency list is generated by gen_initramfs.sh -l

-include $(obj)/.initramfs_data.cpio.d

do not try to update files included in initramfs

$(deps_initramfs): ;

quiet_cmd_initfs = GEN $@ cmd_initfs =
$(CONFIG_SHELL) $< -o $@ -l $(obj)/.initramfs_data.cpio.d
$(if $(CONFIG_INITRAMFS_ROOT_UID), -u $(CONFIG_INITRAMFS_ROOT_UID))
$(if $(CONFIG_INITRAMFS_ROOT_GID), -g $(CONFIG_INITRAMFS_ROOT_GID))
$(ramfs-input)

We rebuild initramfs_data.cpio if:

1) Any included file is newer than initramfs_data.cpio

2) There are changes in which files are included (added or deleted)

3) If gen_init_cpio are newer than initramfs_data.cpio

4) Arguments to gen_initramfs.sh changes

$(obj)/initramfs_data.cpio: $(src)/gen_initramfs.sh $(obj)/gen_init_cpio $(deps_initramfs) FORCE $(call if_changed,initfs)

endif

$(obj)/initramfs_inc_data: $(cpio-data) FORCE $(call if_changed,$(compress-y))

targets += initramfs_data.cpio initramfs_inc_data

subdir-$(CONFIG_UAPI_HEADER_TEST) += include