[PATCH] powerpc/32: Include .branch_lt in data section

[Michael Ellerman]

Alan Modra <amodra at gmail.com> writes:
> On Thu, Nov 15, 2018 at 11:47:52PM +1100, Michael Ellerman wrote:
>> Alan Modra <amodra at gmail.com> writes:
>> 
>> > On Wed, Nov 14, 2018 at 01:32:18PM +1030, Joel Stanley wrote:
>> >> I wasn't sure where this should go or if the ordering matters.
>> >
>> > The usual answer is: "Look at where the section goes in the standard
>> > linker scripts."   But that doesn't apply here.  The section will be
>> > empty for a kernel build so it doesn't matter where it goes.
>> 
>> If it's empty why don't we just discard it?
>
> That can be a recipe for finding linker bugs.  Not that I'm against
> you finding linker bugs.  ;-)

Seems we might have found a linker bug :)

With a binutils 2.29 toolchain discarding .branch_lt causes a segfault
when linking:

  http://kisskb.ellerman.id.au/kisskb/buildresult/13618838/log/

  /kisskb/src/scripts/link-vmlinux.sh: line 85: 74627 Segmentation fault      (core dumped) ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} -T ${lds} ${objects}


That toolchain is here:

  https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/5.5.0/x86_64-gcc-5.5.0-nolibc-powerpc64-linux.tar.xz

It seems to be better with binutils 2.30, it doesn't crash but still
doesn't link:

  http://kisskb.ellerman.id.au/kisskb/buildresult/13620269/log/

  /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld: linkage table error against `0002bf55.xdp_rxq_info_reg_mem_model'
  /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld: stubs don't match calculated size
  /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld: can not build stubs: Bad value
  make[1]: *** [/kisskb/src/Makefile:1036: vmlinux] Error 1

So I guess I'll take this version of the patch for now.

cheers