diff options
| -rw-r--r-- | init/Kconfig | 5 | ||||
| -rw-r--r-- | lib/decompress_unxz.c | 14 | ||||
| -rwxr-xr-x | scripts/xz_wrap.sh | 142 |
3 files changed, 152 insertions, 9 deletions
diff --git a/init/Kconfig b/init/Kconfig index 5783a0b87517..583cb07176a9 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -310,8 +310,9 @@ config KERNEL_XZ BCJ filters which can improve compression ratio of executable code. The size of the kernel is about 30% smaller with XZ in comparison to gzip. On architectures for which there is a BCJ - filter (i386, x86_64, ARM, IA-64, PowerPC, and SPARC), XZ - will create a few percent smaller kernel than plain LZMA. + filter (i386, x86_64, ARM, ARM64, RISC-V, big endian PowerPC, + and SPARC), XZ will create a few percent smaller kernel than + plain LZMA. The speed is about the same as with LZMA: The decompression speed of XZ is better than that of bzip2 but worse than gzip diff --git a/lib/decompress_unxz.c b/lib/decompress_unxz.c index 46aa3be13fc5..cae00395d7a6 100644 --- a/lib/decompress_unxz.c +++ b/lib/decompress_unxz.c @@ -126,11 +126,21 @@ #ifdef CONFIG_X86 # define XZ_DEC_X86 #endif -#ifdef CONFIG_PPC +#if defined(CONFIG_PPC) && defined(CONFIG_CPU_BIG_ENDIAN) # define XZ_DEC_POWERPC #endif #ifdef CONFIG_ARM -# define XZ_DEC_ARM +# ifdef CONFIG_THUMB2_KERNEL +# define XZ_DEC_ARMTHUMB +# else +# define XZ_DEC_ARM +# endif +#endif +#ifdef CONFIG_ARM64 +# define XZ_DEC_ARM64 +#endif +#ifdef CONFIG_RISCV +# define XZ_DEC_RISCV #endif #ifdef CONFIG_SPARC # define XZ_DEC_SPARC diff --git a/scripts/xz_wrap.sh b/scripts/xz_wrap.sh index c8c36441ab70..f19369687030 100755 --- a/scripts/xz_wrap.sh +++ b/scripts/xz_wrap.sh @@ -6,14 +6,146 @@ # # Author: Lasse Collin <lasse.collin@tukaani.org> +# This has specialized settings for the following archs. However, +# XZ-compressed kernel isn't currently supported on every listed arch. +# +# Arch Align Notes +# arm 2/4 ARM and ARM-Thumb2 +# arm64 4 +# csky 2 +# loongarch 4 +# mips 2/4 MicroMIPS is 2-byte aligned +# parisc 4 +# powerpc 4 Uses its own wrapper for compressors instead of this. +# riscv 2/4 +# s390 2 +# sh 2 +# sparc 4 +# x86 1 + +# A few archs use 2-byte or 4-byte aligned instructions depending on +# the kernel config. This function is used to check if the relevant +# config option is set to "y". +is_enabled() +{ + grep -q "^$1=y$" include/config/auto.conf +} + +# XZ_VERSION is needed to disable features that aren't available in +# old XZ Utils versions. +XZ_VERSION=$($XZ --robot --version) || exit +XZ_VERSION=$(printf '%s\n' "$XZ_VERSION" | sed -n 's/^XZ_VERSION=//p') + +# Assume that no BCJ filter is available. BCJ= -LZMA2OPTS= +# Set the instruction alignment to 1, 2, or 4 bytes. +# +# Set the BCJ filter if one is available. +# It must match the #ifdef usage in lib/decompress_unxz.c. case $SRCARCH in - x86) BCJ=--x86 ;; - powerpc) BCJ=--powerpc ;; - arm) BCJ=--arm ;; - sparc) BCJ=--sparc ;; + arm) + if is_enabled CONFIG_THUMB2_KERNEL; then + ALIGN=2 + BCJ=--armthumb + else + ALIGN=4 + BCJ=--arm + fi + ;; + + arm64) + ALIGN=4 + + # ARM64 filter was added in XZ Utils 5.4.0. + if [ "$XZ_VERSION" -ge 50040002 ]; then + BCJ=--arm64 + else + echo "$0: Upgrading to xz >= 5.4.0" \ + "would enable the ARM64 filter" \ + "for better compression" >&2 + fi + ;; + + csky) + ALIGN=2 + ;; + + loongarch) + ALIGN=4 + ;; + + mips) + if is_enabled CONFIG_CPU_MICROMIPS; then + ALIGN=2 + else + ALIGN=4 + fi + ;; + + parisc) + ALIGN=4 + ;; + + powerpc) + ALIGN=4 + + # The filter is only for big endian instruction encoding. + if is_enabled CONFIG_CPU_BIG_ENDIAN; then + BCJ=--powerpc + fi + ;; + + riscv) + if is_enabled CONFIG_RISCV_ISA_C; then + ALIGN=2 + else + ALIGN=4 + fi + + # RISC-V filter was added in XZ Utils 5.6.0. + if [ "$XZ_VERSION" -ge 50060002 ]; then + BCJ=--riscv + else + echo "$0: Upgrading to xz >= 5.6.0" \ + "would enable the RISC-V filter" \ + "for better compression" >&2 + fi + ;; + + s390) + ALIGN=2 + ;; + + sh) + ALIGN=2 + ;; + + sparc) + ALIGN=4 + BCJ=--sparc + ;; + + x86) + ALIGN=1 + BCJ=--x86 + ;; + + *) + echo "$0: Arch-specific tuning is missing for '$SRCARCH'" >&2 + + # Guess 2-byte-aligned instructions. Guessing too low + # should hurt less than guessing too high. + ALIGN=2 + ;; +esac + +# Select the LZMA2 options matching the instruction alignment. +case $ALIGN in + 1) LZMA2OPTS= ;; + 2) LZMA2OPTS=lp=1 ;; + 4) LZMA2OPTS=lp=2,lc=2 ;; + *) echo "$0: ALIGN wrong or missing" >&2; exit 1 ;; esac # Use single-threaded mode because it compresses a little better |