From 7ce7e984ab2b218d6e92d5165629022fe2daf9ee Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 10 Jan 2022 03:15:27 +0900 Subject: 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 Reviewed-by: Nicolas Schier --- usr/Makefile | 5 ----- 1 file changed, 5 deletions(-) (limited to 'usr') diff --git a/usr/Makefile b/usr/Makefile index 7374873a539f..cc0d2824e100 100644 --- a/usr/Makefile +++ b/usr/Makefile @@ -3,11 +3,6 @@ # kbuild file for usr/ - including initramfs image # -# cmd_bzip2, cmd_lzma, cmd_lzo, cmd_lz4 from scripts/Makefile.lib appends the -# size at the end of the compressed file, which unfortunately does not work -# with unpack_to_rootfs(). Make size_append no-op. -override size_append := : - compress-y := shipped compress-$(CONFIG_INITRAMFS_COMPRESSION_GZIP) := gzip compress-$(CONFIG_INITRAMFS_COMPRESSION_BZIP2) := bzip2 -- cgit v1.2.3-59-g8ed1b