From: Kienan Stewart Date: Thu, 10 Aug 2023 19:51:34 +0000 (-0400) Subject: jjb: Adjust gcc and flags for building old kernels with gcc-11/12 X-Git-Url: https://git.liburcu.org/?a=commitdiff_plain;h=a86b55bcdc811bd629795e5d2759cd4399e7c825;p=lttng-ci.git jjb: Adjust gcc and flags for building old kernels with gcc-11/12 A number of small tweaks are required for building with gcc 11, 12, and 4.8 with more recent binutils. Change-Id: I2c9dc91eb8a9ce9f4e237e82a2590931a2857bda --- diff --git a/scripts/lttng-modules/param-build.sh b/scripts/lttng-modules/param-build.sh index 81389bd..c5d4407 100644 --- a/scripts/lttng-modules/param-build.sh +++ b/scripts/lttng-modules/param-build.sh @@ -29,11 +29,15 @@ if [ -z "${arch:-}" ] ; then arch="${platforms:-}" fi fi + cross_arch=${cross_arch:-} ktag=${ktag:-} kgitrepo=${kgitrepo:-} mversion=${mversion:-} mgitrepo=${mgitrepo:-} +make_args=() + +DEBUG=${DEBUG:-} ## FUNCTIONS ## @@ -56,7 +60,6 @@ vergt() { [ "$1" = "$2" ] && return 1 || vergte "$1" "$2" } - git_clone_modules_sources() { mkdir -p "$MODULES_GIT_DIR" @@ -124,7 +127,16 @@ select_compiler() { set +e for cc in $(list_gccs) ; do - if "${CROSS_COMPILE:-}${cc}" -I include/ -D__LINUX_COMPILER_H -D__LINUX_COMPILER_TYPES_H -E include/linux/compiler-gcc.h; then + if "${CROSS_COMPILE:-}${cc}" -I include/ -D__LINUX_COMPILER_H -D__LINUX_COMPILER_TYPES_H -E include/linux/compiler-gcc.h; then + cc_version=$(echo "${cc}" | cut -d'-' -f2) + if { verlt "${kversion}" "5.17"; } && { vergt "${cc_version}" "11"; } ; then + # Using gcc-12+ with '-Wuse-after-free' breaks the build of older + # kernels (in particular, objtool). Some releases on LTS + # branches between 4.x and 5.15 can be built with gcc-12. + # @see https://lore.kernel.org/lkml/20494.1643237814@turing-police/ + # @see https://gitlab.com/linux-kernel/stable/-/commit/52a9dab6d892763b2a8334a568bd4e2c1a6fde66 + continue + fi selected_cc="$cc" break fi @@ -132,35 +144,106 @@ select_compiler() { set -e + # Force gcc-4.8 for kernels before 4.4 + if { verlt "$kversion" "4.4"; }; then + selected_cc='gcc-4.8' + fi + if [ "x$selected_cc" = "x" ]; then echo "Found no suitable compiler." exit 1 fi - # Force gcc-4.8 for kernels before 3.18 - if { verlt "$kversion" "3.18"; }; then - selected_cc=gcc-4.8 - fi - + _KAFLAGS=() + _KCFLAGS=() + _KCPPFLAGS=() + _HOSTCFLAGS=() if [ "$selected_cc" != "gcc-4.8" ]; then # Older kernel Makefiles do not expect the compiler to default to PIE - KAFLAGS="-fno-pie" - KCFLAGS="-fno-pie -no-pie -fno-stack-protector" - KCPPFLAGS="-fno-pie" - export KAFLAGS KCFLAGS KCPPFLAGS + _KAFLAGS+=(-fno-pie) + _KCFLAGS+=( + -fno-pie + -no-pie + -fno-stack-protector + ) + _KCPPFLAGS+=(-fno-pie) + fi + + selected_cc_version="$(echo "${selected_cc}" | cut -d'-' -f2)" + if { vergte "${selected_cc_version}" "10"; } && { verlt "${kversion}" "5.10"; } ; then + # gcc-10 changed the default from '-fcommon' to '-fno-common', which + # causes a linker failure. '-fcommon' can be set on the HOSTCFLAGS + # to avoid the issue. + # @see https://gitlab.com/linux-kernel/stable/-/commit/e33a814e772cdc36436c8c188d8c42d019fda639 + _HOSTCFLAGS+=(-fcommon) + fi + + if [ "${cross_arch:-}" == "armhf" ] ; then + if { verlt "${kversion}" "5.14"; } ; then + # Work-around for producing instructions that aren't valid for the + # default architectures. + # Eg. Error: selected processor does not support `cpsid i' in ARM mode + _KCFLAGS+=(-march=armv7-a -mfpu=vfpv3-d16) + _KCPPFLAGS+=(-march=armv7-a -mfpu=vfpv3-d16) + fi + fi + + if { vergt "${selected_cc_version}" "8"; } && { vergte "${kversion}" "4.15"; } && { verlt "${kversion}" "4.17"; } ; then + # This was added to -Wall in gcc 9 but some kernels do not include the fixes + # @see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88583 + _KCFLAGS+=(-Wno-error=packed-not-aligned) fi + export KAFLAGS="${_KAFLAGS[*]}" + export KCFLAGS="${_KCFLAGS[*]}" + export KCPPFLAGS="${_KCPPFLAGS[*]}" + export HOSTCFLAGS="${_HOSTCFLAGS[*]}" export CC="${CROSS_COMPILE:-}${selected_cc}" export HOSTCC="${selected_cc}" + make_args=( + CC="${CC}" + HOSTCC="${HOSTCC}" + HOSTCFLAGS="${HOSTCFLAGS:-}" + ) + if [ -n "${DEBUG}" ] ; then + make_args+=( + V=1 + ) + fi cd - } +patch_linux_kernel() { + local commit_hash + commit_hash="$1" + set +e + git -C "${LINUX_GIT_REF_REPO_DIR}" format-patch -n1 --stdout "${commit_hash}" | patch -p1 + set -e + if [ "$?" -gt 1 ] ; then + echo "Serious issue patching" + exit 1 + fi +} build_linux_kernel() { cd "$LINUX_SRCOBJ_DIR" - kversion=$(make -s kernelversion) + kversion=$(make -s kernelversion "${make_args[@]}") + + if { verlt "${kversion}" "3.3"; } && [ "${vanilla_config}" = "imx_v6_v7_defconfig" ] ; then + # imx_v6_v7 didn't exist before 06965c39b4c63933fa0a1cde2237ef85477c5655 + if { verlt "${kversion}" "3.2"; } ; then + vanilla_config='mx5_defconfig' + else + vanilla_config='mx51_defconfig' + fi + fi + + if { verlt "${kversion}" "3.13"; } && [ "${vanilla_config}" = "pseries_le_defconfig" ] ; then + # pseries_le_deconfig was introduced in f53e462e907cbaed29c49c0f10f5b8f614e1bf1d + vanilla_config='pseries_defconfig' + fi # Generate kernel configuration case "$ktag" in @@ -199,10 +282,20 @@ build_linux_kernel() { export ARCH="i386" fi - make "${vanilla_config}" + make "${vanilla_config}" "${make_args[@]}" ;; esac + if [ "${vanilla_config}" = "pseries_defconfig" ] && [ "${cross_arch}" = "ppc64el" ] ; then + # @see diff <(git show v3.13:arch/powerpc/configs/pseries_defconfig) <(git show v3.13:arch/powerpc/configs/pseries_le_defconfig) + scripts/config --enable CONFIG_CPU_LITTLE_ENDIAN + scripts/config --enable CONFIG_CMA + scripts/config --disable CONFIG_XMON_DEFAULT + # scripts/config --disable CONFIG_VIRTUALIZATION + # scripts/config --disable CONFIG_KVM_BOOK3S_64 + scripts/config --disable CONFIG_KVM_BOOK3S_64_HV + fi + # oldnoconfig was renamed in 4.19 if vergte "$kversion" "4.19"; then update_conf_target="olddefconfig" @@ -226,6 +319,130 @@ build_linux_kernel() { fi fi + if { verlt "${kversion}" "5.11"; } && { vergte "${kversion}" "4.10"; } ; then + # Binutils > 2.35 strips empty symbol tables, causing obltool to fail + # in certain cases when files are empty. + # @see https://gitlab.com/linux-kernel/stable/-/commit/1d489151e9f9d1647110277ff77282fe4d96d09b + # + # There doesn't seem to be any LD/AS/AR flags to control this behaviour, + # therefore patching tools/objtool/elf.c is attempted. + patch_linux_kernel 1d489151e9f9d1647110277ff77282fe4d96d09b + if { verlt "${kversion}" "4.18"; } ; then + patch_linux_kernel e81e0724432542af8d8c702c31e9d82f57b1ff31 + fi + fi + + if { vergt "${selected_cc_version}" "7"; } && { vergte "${kversion}" "4.15"; } && { verlt "${kversion}" "4.17"; } ; then + # Builds fail due to -Werror=restrict in pager.o and str_error_r.o + if { verlt "${kversion}" "4.16"; } ; then + # This is patched since objtool's Makefile doesn't respect HOSTCFLAGS + # @see https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ad343a98e74e85aa91d844310e797f96fee6983b + patch_linux_kernel ad343a98e74e85aa91d844310e797f96fee6983b + fi + if { verlt "${kversion}" "4.17"; } ; then + # This is patched since objtool's Makefile doesn't respect HOSTCFLAGS + # @see https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=854e55ad289ef8888e7991f0ada85d5846f5afb9 + patch_linux_kernel 854e55ad289ef8888e7991f0ada85d5846f5afb9 + fi + + # More recent compiler optimizations expose build errors with netronome. + # It seems easier to disable the driver than to attempt patching. + scripts/config --disable CONFIG_NET_VENDOR_NETRONOME + scripts/config --disable CONFIG_MICREL_PHY + + # Duplicate decalarations of __force_order + # @see https://gitlab.com/linux-kernel/stable/-/commit/df6d4f9db79c1a5d6f48b59db35ccd1e9ff9adfc + # However, kaslr_64.c doesn't exit in 4.15, 4.16, it's named pagetable.c + if [ -f arch/x86/boot/compressed/pagetable.c ] ; then + sed -i '/^unsigned long __force_order;$/d' arch/x86/boot/compressed/pagetable.c + fi + fi + + if { vergte "${kversion}" "4.15"; } && { verlt "${kversion}" "4.18"; } ; then + # Some old kernels fail to build when make is too new + # @see https://gitlab.com/linux-kernel/stable/-/commit/9feeb638cde083c737e295c0547f1b4f28e99583 + patch_linux_kernel 9564a8cf422d7b58f6e857e3546d346fa970191e + # @see https://gitlab.com/linux-kernel/stable/-/commit/9feeb638cde083c737e295c0547f1b4f28e99583 + patch_linux_kernel 9feeb638cde083c737e295c0547f1b4f28e99583 + fi + + if { vergte "${kversion}" "4.12"; } && { verlt "${kversion}" "4.18"; } ; then + # Old kernels can fail to build while on newer host kernels + # @see https://gitlab.com/linux-kernel/stable/-/commit/dfbd199a7cfe3e3cd8531e1353cdbd7175bfbc5e + # + patch_linux_kernel dfbd199a7cfe3e3cd8531e1353cdbd7175bfbc5e + fi + + if { vergte "${kversion}" "3.18"; } && { verlt "${kversion}" "4.4"; } ; then + # Compatibility with binutils >= ~ 2.31 + patch_linux_kernel b21ebf2fb4cde1618915a97cc773e287ff49173e + fi + + # The above patch only partially applies linux 3.17, and has been, so a + # rebased version is used instead. + if { vergte "${kversion}" "3.17"; } && { verlt "${kversion}" "3.18"; } ; then + cat <<'EOF' | patch -p1 +diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c +index 48598105..0652c5b6 100644 +--- a/arch/x86/kernel/machine_kexec_64.c ++++ b/arch/x86/kernel/machine_kexec_64.c +@@ -516,6 +516,7 @@ int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr, + goto overflow; + break; + case R_X86_64_PC32: ++ case R_X86_64_PLT32: + value -= (u64)address; + *(u32 *)location = value; + break; +diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c +index e69f9882..7c6bc9fe 100644 +--- a/arch/x86/kernel/module.c ++++ b/arch/x86/kernel/module.c +@@ -180,6 +180,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, + goto overflow; + break; + case R_X86_64_PC32: ++ case R_X86_64_PLT32: + val -= (u64)loc; + *(u32 *)loc = val; + #if 0 +diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c +index bbb1d225..8deeacbc 100644 +--- a/arch/x86/tools/relocs.c ++++ b/arch/x86/tools/relocs.c +@@ -763,6 +763,7 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym, + switch (r_type) { + case R_X86_64_NONE: + case R_X86_64_PC32: ++ case R_X86_64_PLT32: + /* + * NONE can be ignored and PC relative relocations don't + * need to be adjusted. +EOF + fi + + if ( { vergte "${kversion}" "3.15"; } && { verlt "${kversion}" "4.4"; } ) || + ( { vergte "${kversion}" "4.15"; } && { verlt "${kversion}" "4.17"; } ); then + # While the original motivation of this patch is for fixing builds using + # clang, the same error occurs between linux >= 3.15 and < 4.4, and in + # 4.15, 4.16. + # + # This patch only partially applies due to changes in kernel/Makefile, + # so a supplementary patch is needed + # + # Without this patch, builds fail with + # Cannot find symbol for section 2: .text. + # kernel/elfcore.o: failed + # + # @see https://github.com/linuxppc/issues/issues/388 + # @see https://lore.kernel.org/lkml/20201204165742.3815221-2-arnd@kernel.org/ + # + patch_linux_kernel 6e7b64b9dd6d96537d816ea07ec26b7dedd397b9 + if grep -q elfcore.o kernel/Makefile ; then + sed -i '/^.* += elfcore.o$/d' kernel/Makefile + fi + fi + # Newer binutils don't accept 3 operand 'cmp' instructions on ppc64 # Convert them to 'cmpw' which was previously done silently if verlt "$kversion" "4.9"; then @@ -253,9 +470,21 @@ build_linux_kernel() { echo "header-y += linkage.h" >> include/linux/Kbuild fi + if [ "${cross_arch}" = "powerpc" ] ; then + if { vergte "${kversion}" "4.15"; } && { verlt "${kversion}" "4.16"; } ; then + # Avoid register errors such as + # aes_generic.c:(.text+0x4e0): undefined reference to `_restgpr_31_x' + # @see https://gitlab.com/linux-kernel/stable/-/commit/148b974deea927f5dbb6c468af2707b488bfa2de + make_args+=( + CFLAGS_aes_generic.o='' + ) + fi + fi + # GCC 4.8 if [ "$HOSTCC" == "gcc-4.8" ]; then - scripts/config --disable CONFIG_CC_STACKPROTECTOR_STRONG + scripts/config --disable CONFIG_CC_STACKPROTECTOR_STRONG + scripts/config --disable CONFIG_PPC_OF_BOOT_TRAMPOLINE fi # Don't try to sign modules @@ -291,6 +520,7 @@ build_linux_kernel() { # Don't fail the build on warnings scripts/config --disable CONFIG_WERROR + scripts/config --enable CONFIG_PPC_DISABLE_WERROR # Set required options scripts/config --enable CONFIG_TRACEPOINTS @@ -305,18 +535,19 @@ build_linux_kernel() { scripts/config --enable CONFIG_EVENT_TRACING scripts/config --enable CONFIG_KRETPROBES - # Debug - #cat .config + if [ -n "${DEBUG}" ] ; then + cat .config + fi - make "$update_conf_target" CC="$CC" - make -j"$NPROC" CC="$CC" + make "$update_conf_target" "${make_args[@]}" + make -j"$NPROC" "${make_args[@]}" - krelease=$(make -s kernelrelease CC="$CC") + krelease=$(make -s kernelrelease "${mark_args[@]}") # Save the kernel and modules mkdir -p "$LINUX_INSTOBJ_DIR/boot" - make INSTALL_MOD_PATH="$LINUX_INSTOBJ_DIR" INSTALL_MOD_STRIP=1 modules_install CC="$CC" - make INSTALL_MOD_PATH="$LINUX_INSTOBJ_DIR" INSTALL_PATH="$LINUX_INSTOBJ_DIR/boot" install CC="$CC" + make INSTALL_MOD_PATH="$LINUX_INSTOBJ_DIR" INSTALL_MOD_STRIP=1 modules_install "${make_args[@]}" + make INSTALL_MOD_PATH="$LINUX_INSTOBJ_DIR" INSTALL_PATH="$LINUX_INSTOBJ_DIR/boot" install "${make_args[@]}" rm -f "$LINUX_INSTOBJ_DIR/lib/modules/${krelease}/source" "$LINUX_INSTOBJ_DIR/lib/modules/${krelease}/build" ln -s ../../../../sources "$LINUX_INSTOBJ_DIR/lib/modules/${krelease}/source" ln -s ../../../../sources "$LINUX_INSTOBJ_DIR/lib/modules/${krelease}/source" @@ -420,21 +651,21 @@ extract_distro_headers() { make clean # And regen the modules support files - make modules_prepare CC="$CC" + make modules_prepare "${make_args[@]}" # On powerpc 32bits this object is required to link modules if [ "${karch}" = "powerpc" ]; then if [ "x$(scripts/config -s CONFIG_PPC64)" = "xy" ] && vergte "${kversion}" "5.4"; then : else - make arch/powerpc/lib/crtsavres.o CC="$CC" + make arch/powerpc/lib/crtsavres.o "${make_args[@]}" fi fi # On arm64 between 4.13 and 4.15 this object is required to build with ftrace support if [ "${karch}" = "arm64" ]; then if [ -f "arch/arm64/kernel/ftrace-mod.S" ]; then - make arch/arm64/kernel/ftrace-mod.o CC="$CC" + make arch/arm64/kernel/ftrace-mod.o "${make_args[@]}" fi fi @@ -473,7 +704,7 @@ build_modules() { set +e # Build modules - KERNELDIR="${kdir}" make -j"${NPROC}" V=1 CC="$CC" + KERNELDIR="${kdir}" make -j"${NPROC}" V=1 "${make_args[@]}" ret=$? set -e @@ -492,7 +723,7 @@ build_modules() { else # Regular build # Build modules against full kernel sources - KERNELDIR="${kdir}" make -j"${NPROC}" V=1 CC="$CC" + KERNELDIR="${kdir}" make -j"${NPROC}" V=1 "${make_args[@]}" # Install modules to build dir KERNELDIR="${kdir}" make INSTALL_MOD_PATH="${outdir}" modules_install @@ -696,6 +927,14 @@ esac select_compiler +selected_cc_version="$(echo "${selected_cc}" | cut -d'-' -f2)" +# lttng-modules requires gcc >= 5.1 for aarch64 +# @see https://github.com/lttng/lttng-modules/commit/be06402dbdbea2f3394e60ec15c5d3356e2be416 +if { verlt "${selected_cc_version}" "5.1"; } && [ "${cross_arch}" = "arm64" ] ; then + echo "Building lltng-modules on aarch64 requires gcc >= 5.1" + exit 0 +fi + ## BUILD modules # Either we downloaded a pre-build kernel or we built it and uploaded # the archive for future builds.