[PATCH v3] RISC-V: Enable dead code elimination

[Nick Desaulniers]

On Tue, Jun 20, 2023 at 4:17 PM Palmer Dabbelt <palmer at rivosinc.com> wrote:
>
> On Tue, 20 Jun 2023 13:13:06 PDT (-0700), ndesaulniers at google.com wrote:
> > On Wed, May 17, 2023 at 04:29:36PM +0800, Zhangjin Wu wrote:
> >> Select CONFIG_HAVE_LD_DEAD_CODE_DATA_ELIMINATION for RISC-V, allowing
> >> the user to enable dead code elimination. In order for this to work,
> >> ensure that we keep the alternative table by annotating them with KEEP.
> >>
> >
> > Just cross referencing the report from Palmer against v2; I see orphan
> > section warnings from the linker related to the EFI stub when building
> > allmodconfig with this patch applied.
> >
> > v2: thread for reference.
> > https://lore.kernel.org/linux-riscv/CAKwvOdmsgMN5oQpDLh12D0X-CfQDtHC-EtxHcBnADkhnyitMKQ@mail.gmail.com/
>
> Sorry for replying to the v2, I'm marking that as superseeded in
> patchwork.  IIUC it is a real issue on your end too?  I'm also not 100%
> sure about the hang, I just let LLD cook for about 10 minutes before I
> noticed it was still running and posted.

Yes; if this is merged, our CI builds of ARCH=riscv allmodconfig will go red.

I assume a linker script somewhere needs to be updated, but I haven't
found if/where the efi stub's is.

drivers/firmware/efi/libstub/zboot.lds perhaps?

On Tue, Jun 20, 2023 at 4:22 PM Conor Dooley <conor at kernel.org> wrote:
>
> Repeating myself for the sake of the archives or w/e, two different
> submitters with differing version numbers. The v2 from Jisheng is more
> recent than the v3 here from Zhangjin, they agreed in this mail thread
> to merge their work.

-- 
Thanks,
~Nick Desaulniers