Re: Building arm64 EFI stub with -fpie breaks build of 4.9.x (undefined reference to `__efistub__GLOBAL_OFFSET_TABLE_')

[Ard Biesheuvel]

On Thu, 6 Jun 2019 at 11:40, Rolf Eike Beer <eb@xxxxxxxxx> wrote:
>
> Ard Biesheuvel wrote:
> > On Thu, 6 Jun 2019 at 09:50, Rolf Eike Beer <eb@xxxxxxxxx> wrote:
> > > Am Donnerstag, 6. Juni 2019, 09:38:41 CEST schrieb Rolf Eike Beer:
> > > > Greg KH wrote:
> > > > > On Wed, Jun 05, 2019 at 05:19:40PM +0200, Rolf Eike Beer wrote:
> > > > > > I decided to dig out a toy project which uses a DragonBoard 410c.
> > > > > > This
> > > > > > has
> > > > > > been "running" with kernel 4.9, which I would keep this way for
> > > > > > unrelated
> > > > > > reasons. The vanilla 4.9 kernel wasn't bootable back then, but it
> > > > > > was
> > > > > > buildable, which was good enough.
> > > > > >
> > > > > > Upgrading the kernel to 4.9.180 caused the boot to suddenly fail:
> > > > > >
> > > > > > aarch64-unknown-linux-gnueabi-ld:
> > > > > > ./drivers/firmware/efi/libstub/lib.a(arm64- stub.stub.o): in
> > > > > > function
> > > > > > `handle_kernel_image':
> > > > > > /tmp/e2/build/linux-4.9.139/drivers/firmware/efi/libstub/arm64-stub.
> > > > > > c:63
> > > > > >
> > > > > > undefined reference to `__efistub__GLOBAL_OFFSET_TABLE_'
> > > > > > aarch64-unknown-linux-gnueabi-ld:
> > > > > > ./drivers/firmware/efi/libstub/lib.a(arm64- stub.stub.o): relocation
> > > > > > R_AARCH64_ADR_PREL_PG_HI21 against symbol
> > > > > > `__efistub__GLOBAL_OFFSET_TABLE_' which may bind externally can not
> > > > > > be
> > > > > > used when making a shared object; recompile with -fPIC
> > > > > > /tmp/e2/build/linux-4.9.139/drivers/firmware/efi/libstub/arm64-stub.
> > > > > > c:63
> > > > > >
> > > > > > (.init.text+0xc): dangerous relocation: unsupported relocation
> > > > > > /tmp/e2/build/linux-4.9.139/Makefile:1001: recipe for target
> > > > > > 'vmlinux'
> > > > > > failed -make[1]: *** [vmlinux] Error 1
> > > > > >
> > > > > > This is caused by commit 27b5ebf61818749b3568354c64a8ec2d9cd5ecca
> > > > > > from
> > > > > > linux-4.9.y (which is 91ee5b21ee026c49e4e7483de69b55b8b47042be),
> > > > > > reverting
> > > > > > this commit fixes the build.
> > > > > >
> > > > > > This happens with vanilla binutils 2.32 and gcc 8.3.0 as well as
> > > > > > 9.1.0.
> > > > > > See
> > > > > > the attached .config for reference.
> > > > > >
> > > > > > If you have questions or patches just ping me.
> > > > >
> > > > > Does Linus's latest tree also fail for you (or 5.1)?
> > > >
> > > > 5.1.7 with the same config as before and "make olddefconfig" builds for
> > > > me.
> > >
> > > Just for the fun of it: both 4.19 and 4.19.48 also work.
>
> > Could you please check whether patch
> > 60f38de7a8d4e816100ceafd1b382df52527bd50 applies cleanly, and whether
> > it fixes the problem? Thanks.
>
> The part in drivers/firmware/efi/libstub/arm-stub.c needs to be applied by
> hand, but afterwards things build fine.
>

Thanks.

I'll send out a backport.