From: Javier Martinez Canillas javierm@redhat.com

commit ff2e6efda0d5c51b33e2bcc0b0b981ac0a0ef214 upstream.

[backported for dependency, skipped Makefile.modfinal change, because module BTF is not supported in 5.10]

The ccache tool can be used to speed up cross-compilation, by calling the compiler and binutils through ccache. For example, following should work:

$ export ARCH=arm64 CROSS_COMPILE="ccache aarch64-linux-gnu-"

$ make M=drivers/gpu/drm/rockchip/

but pahole fails to extract the BTF info from DWARF, breaking the build:

CC [M] drivers/gpu/drm/rockchip//rockchipdrm.mod.o LD [M] drivers/gpu/drm/rockchip//rockchipdrm.ko BTF [M] drivers/gpu/drm/rockchip//rockchipdrm.ko aarch64-linux-gnu-objcopy: invalid option -- 'J' Usage: aarch64-linux-gnu-objcopy [option(s)] in-file [out-file] Copies a binary file, possibly transforming it in the process ... make[1]: *** [scripts/Makefile.modpost:156: __modpost] Error 2 make: *** [Makefile:1866: modules] Error 2

this fails because OBJCOPY is set to "ccache aarch64-linux-gnu-copy" and later pahole is executed with the following command line:

LLVM_OBJCOPY=$(OBJCOPY) $(PAHOLE) -J --btf_base vmlinux $@

which gets expanded to:

LLVM_OBJCOPY=ccache aarch64-linux-gnu-objcopy pahole -J ...

instead of:

LLVM_OBJCOPY="ccache aarch64-linux-gnu-objcopy" pahole -J ...

Fixes: 5f9ae91f7c0d ("kbuild: Build kernel module BTFs if BTF is enabled and pahole supports it") Signed-off-by: Javier Martinez Canillas javierm@redhat.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Acked-by: Andrii Nakryiko andrii@kernel.org Acked-by: Arnaldo Carvalho de Melo acme@redhat.com Link: https://lore.kernel.org/bpf/20210526215228.3729875-1-javierm@redhat.com --- scripts/link-vmlinux.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index cdfccbfed452..72bf14df6903 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -162,7 +162,7 @@ gen_btf() vmlinux_link ${1}

info "BTF" ${2} - LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${extra_paholeopt} ${1} + LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${extra_paholeopt} ${1}

# Create ${2} which contains just .BTF section but no symbols. Add # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all

From: Jiri Olsa jolsa@redhat.com

commit 9741e07ece7c247dd65e1aa01e16b683f01c05a8 upstream.

[skipped --btf_gen_floats option in pahole-flags.sh, skipped Makefile.modfinal change, because there's no BTF kmod support, squashing in 'exit 0' change from merge commit fc02cb2b37fe]

Using new PAHOLE_FLAGS variable to pass extra arguments to pahole for both vmlinux and modules BTF data generation.

Adding new scripts/pahole-flags.sh script that detect and prints pahole options.

[ fixed issues found by kernel test robot ]

Signed-off-by: Jiri Olsa jolsa@kernel.org Signed-off-by: Andrii Nakryiko andrii@kernel.org Acked-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20211029125729.70002-1-jolsa@kernel.org --- Makefile | 3 +++ scripts/link-vmlinux.sh | 8 +------- scripts/pahole-flags.sh | 17 +++++++++++++++++ 3 files changed, 21 insertions(+), 7 deletions(-) create mode 100755 scripts/pahole-flags.sh

diff --git a/Makefile b/Makefile index b824bdb0457c..fc8f1a1c0d98 100644 --- a/Makefile +++ b/Makefile @@ -465,6 +465,8 @@ LZ4 = lz4c XZ = xz ZSTD = zstd

+PAHOLE_FLAGS = $(shell PAHOLE=$(PAHOLE) $(srctree)/scripts/pahole-flags.sh) + CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \ -Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF) NOSTDINC_FLAGS := @@ -518,6 +520,7 @@ export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL +export PAHOLE_FLAGS

# Files to ignore in find ... statements

diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index bbb22be4c8f1..acd07a70a2f4 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -146,7 +146,6 @@ vmlinux_link() gen_btf() { local pahole_ver - local extra_paholeopt=

if ! [ -x "$(command -v ${PAHOLE})" ]; then echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available" @@ -161,13 +160,8 @@ gen_btf()

vmlinux_link ${1}

- if [ "${pahole_ver}" -ge "118" ] && [ "${pahole_ver}" -le "121" ]; then - # pahole 1.18 through 1.21 can't handle zero-sized per-CPU vars - extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_vars" - fi - info "BTF" ${2} - LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${extra_paholeopt} ${1} + LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}

# Create ${2} which contains just .BTF section but no symbols. Add # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all diff --git a/scripts/pahole-flags.sh b/scripts/pahole-flags.sh new file mode 100755 index 000000000000..27445cb72974 --- /dev/null +++ b/scripts/pahole-flags.sh @@ -0,0 +1,17 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +extra_paholeopt= + +if ! [ -x "$(command -v ${PAHOLE})" ]; then + exit 0 +fi + +pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+).([0-9]+)/\1\2/') + +if [ "${pahole_ver}" -ge "118" ] && [ "${pahole_ver}" -le "121" ]; then + # pahole 1.18 through 1.21 can't handle zero-sized per-CPU vars + extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_vars" +fi + +echo ${extra_paholeopt}