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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- scripts/link-vmlinux.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- 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