linux/usr
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
..
include kbuild: move headers_check.pl to usr/include/ 2022-01-08 17:41:00 +09:00
.gitignore .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
default_cpio_list initramfs: add default_cpio_list, and delete -d option support 2020-01-16 00:25:22 +09:00
gen_init_cpio.c initramfs: Check timestamp to prevent broken cpio archive 2021-10-24 13:48:40 +09:00
gen_initramfs.sh kbuild: replace LANG=C with LC_ALL=C 2021-05-02 00:43:35 +09:00
initramfs_data.S initramfs: refactor the initramfs build rules 2020-01-16 00:26:21 +09:00
Kconfig initramfs: Remove redundant dependency of RD_ZSTD on BLK_DEV_INITRD 2021-02-24 15:12:06 +09:00
Makefile kbuild: rename cmd_{bzip2,lzma,lzo,lz4,xzkern,zstd22} 2022-01-14 02:54:05 +09:00