On Wed, May 26, 2021 at 12:53 PM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
>
> On Thu, May 27, 2021 at 1:18 AM Andrii Nakryiko
> <andrii.nakryiko@xxxxxxxxx> wrote:
> >
> > On Tue, May 18, 2021 at 7:23 AM Javier Martinez Canillas
> > <javierm@xxxxxxxxxx> wrote:
> > >
> > > 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-"
>
> Actually, I did not know this...
>
> > >
> > > $ 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: 5f9ae91f7c0 ("kbuild: Build kernel module BTFs if BTF is enabled and pahole supports it")
> > > Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
> > > ---
> > >
> >
> > LGTM. Masahiro, would you like us to take this through bpf tree or
> > you'll apply this to kbuild one?
> >
> > Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> >
> > > scripts/Makefile.modfinal | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
> > > index dd87cea9fba..a7883e45529 100644
> > > --- a/scripts/Makefile.modfinal
> > > +++ b/scripts/Makefile.modfinal
> > > @@ -59,7 +59,7 @@ quiet_cmd_ld_ko_o = LD [M] $@
> > > quiet_cmd_btf_ko = BTF [M] $@
> > > cmd_btf_ko = \
> > > if [ -f vmlinux ]; then \
> > > - LLVM_OBJCOPY=$(OBJCOPY) $(PAHOLE) -J --btf_base vmlinux $@; \
> > > + LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J --btf_base vmlinux $@; \
> > > else \
> > > printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \
> > > fi;
> > > --
> > > 2.31.1
> > >
>
>
> Please feel free to pick it up.
Ok, sounds good.
> I do not know 5f9ae91f7c0.
>
> BTW, I see similar code in scripts/link-vmlinux.sh too.
>
> LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${extra_paholeopt} ${1}
>
> Is it OK to leave it unquoted?
You are right, link-vmlinux.sh should be updated accordingly.
Javier, can you please send v2 and cc bpf@xxxxxxxxxxxxxxx? Thanks!
>
>
> --
> Best Regards
> Masahiro Yamada
