On Tue, 11 Sep 2018 20:49:25 +0900 Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > On Mon, 10 Sep 2018 15:27:20 +0200 > Peter Oberparleiter <oberpar@xxxxxxxxxxxxx> wrote: > > > On 08.09.2018 05:57, Masami Hiramatsu wrote: > > > On Fri, 7 Sep 2018 14:50:59 +0200 > > > Peter Oberparleiter <oberpar@xxxxxxxxxxxxx> wrote: > > > > > >> On 06.09.2018 18:42, Masami Hiramatsu wrote: > > >>> Peter Oberparleiter <oberpar@xxxxxxxxxxxxx> wrote: > > >>>> I've attached a quick fix that should address both problems. I'd > > >>>> appreciate if this patch could get some testing before I post proper fix > > >>>> patches. > > >>> > > >>> Hmm, I'm still not able to reproduce it on powerpc cross build even with > > >>> CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y ... So, sorry I couldn't test this patch. > > >> > > >> Maybe this is related to the compiler/binutils versions used. I'm using > > >> Fedora 28's gcc-powerpc64 and binutils-powerpc64 packages: > > >> > > >> powerpc64-linux-gnu-gcc (GCC) 7.1.1 20170622 (Red Hat Cross 7.1.1-3) > > >> GNU ld version 2.29.1-4.fc28 > > >> > > >> For reference I'm also attaching the config that I used to reproduce the > > >> problem on kernel v4.18. > > >> > > >>>> diff --git a/arch/arm/kernel/vmlinux.lds.h b/arch/arm/kernel/vmlinux.lds.h > > >>>> index ae5fdff18406..2ca33277a28b 100644 > > >>>> --- a/arch/arm/kernel/vmlinux.lds.h > > >>>> +++ b/arch/arm/kernel/vmlinux.lds.h > > >>>> @@ -48,6 +48,7 @@ > > >>>> > > >>>> #define ARM_DISCARD \ > > >>>> *(.ARM.exidx.exit.text) \ > > >>>> + *(.ARM.exidx.text.exit) \ > > >>> > > >>> BTW, why would we need this? > > >> > > >> That's necessary to fix one of the two ARM linker failures reported via > > >> https://lkml.org/lkml/2018/8/24/345 > > >> > > >>>>> `.text.exit' referenced in section `.ARM.exidx.text.exit' of > > >>>>> kernel/trace/trace_clock.o: defined in discarded section `.text.exit' > > >>>>> of kernel/trace/trace_clock.o > > >> > > >> Section ".ARM.exidx.text.exit" refers to ".text.exit" which was > > >> discarded. With the change above, the extraneous section > > >> ".ARM.exidx.text.exit" is also discarded, resolving the linker failure. > > > > > > OK, so your patch fixes following issue too? > > > > > > https://patchwork.kernel.org/patch/10584685/ > > > > Yes it does, by discarding the text.exit section unconditionally. I > > don't think we need to keep any exit-related section introduced by GCOV > > profiling. It is my understanding that the code contained in such a > > section is only relevant for user-space profiling, to process profiling > > data when a program ends. > > > > Also discarding .ARM.exidx.text.exit seems to be more consistent to how > > .ARM.exidx.exit.text is handled. > > > > > In that case, we should drop above patch. > > > > Yes, I agree. > > Hm, with your patch (on linus tree), I still have this error on arm cross build. > > CC init/version.o > AR init/built-in.a > AR built-in.a > LD vmlinux.o > MODPOST vmlinux.o > `.exit.text' referenced in section `.alt.smp.init' of net/dns_resolver/dns_key.o: defined in discarded section `.exit.text' of net/dns_resolver/dns_key.o Ah, sorry, this is not from GCOV, but alternatives for SMP. This should be a different issue. > > I attached my config. > > Since this comes from section discarding, with my patch (which prevent discarding) this error didn't happen. So, this is just a side effect. your patch is good when CONFIG_DNS_RESOLVER=n Thank you, -- Masami Hiramatsu <mhiramat@xxxxxxxxxx>
