From 7e61560628d17ea6b1d8ee370f6d42694cff8758 Mon Sep 17 00:00:00 2001 From: Ulises Mendez Martinez Date: Fri, 4 Sep 2026 15:07:09 +0000 Subject: objtool: Validate disassembler headers in libopcodes probe commit 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries") tested for libopcodes availability by linking a test snippet with a forward declaration of disassemble_init_for_target(). However, testing symbol linkage with an extern declaration only verifies the presence of the library (.so/.a) and bypasses checking for development headers (binutils-dev). On systems where libopcodes is present without development headers installed, the probe succeeds, enabling BUILD_DISAS. Subsequent compilation of objtool then fails: fatal error: 'bfd.h' file not found 113 | #include Additionally, the probe invokes $(HOSTCC) without $(HOSTCFLAGS), ignoring any sysroot or include flags specified for the host compiler. Fix this by including and directly in the test snippet, passing $(HOSTCFLAGS) so host compiler options are respected, and defining PACKAGE="objtool" to satisfy the configuration check in . Fixes: 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries") Fixes: 436326bc525d ("objtool: fix build failure due to missing libopcodes check") Reported-by: Alice Ryhl Assisted-by: Antigravity:Gemini-Next Signed-off-by: Ulises Mendez Martinez Link: https://patch.msgid.link/20260904150710.2997558-1-umendez@google.com Signed-off-by: Josh Poimboeuf --- scripts/xz_wrap.sh | 162 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 162 insertions(+) create mode 100755 scripts/xz_wrap.sh (limited to 'scripts/xz_wrap.sh') diff --git a/scripts/xz_wrap.sh b/scripts/xz_wrap.sh new file mode 100755 index 000000000..f19369687 --- /dev/null +++ b/scripts/xz_wrap.sh @@ -0,0 +1,162 @@ +#!/bin/sh +# SPDX-License-Identifier: 0BSD +# +# This is a wrapper for xz to compress the kernel image using appropriate +# compression options depending on the architecture. +# +# Author: Lasse Collin + +# 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= + +# 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 $SRCARCH in + arm) + if is_enabled CONFIG_THUMB2_KERNEL; then + ALIGN=2 + BCJ=--armthumb + else + ALIGN=4 + BCJ=--arm + fi + ;; + + arm64) + ALIGN=4 + + # ARM64 filter was added in XZ Utils 5.4.0. + if [ "$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 +# (and uses less RAM) than multithreaded mode. +# +# For the best compression, the dictionary size shouldn't be +# smaller than the uncompressed kernel. 128 MiB dictionary +# needs less than 1400 MiB of RAM in single-threaded mode. +# +# On the archs that use this script to compress the kernel, +# decompression in the preboot code is done in single-call mode. +# Thus the dictionary size doesn't affect the memory requirements +# of the preboot decompressor at all. +exec $XZ --check=crc32 --threads=1 $BCJ --lzma2=$LZMA2OPTS,dict=128MiB -- cgit v1.3.1