[RFC PATCH v1] arm: lib: add __gnu_thumb1_case_si

[Tony Dinh]

Hi Francis,

On Sun, Apr 2, 2023 at 3:17 AM Pali Rohár <pali at kernel.org> wrote:
>
> On Saturday 01 April 2023 15:17:59 Tony Dinh wrote:
> > Hi Francis,
> >
> > On Sat, Apr 1, 2023 at 2:55 PM Francis Laniel
> > <francis.laniel at amarulasolutions.com> wrote:
> > >
> > > The assembly for __gnu_thumb1_case_si was taken from upstream gcc and adapted
> > > as width suffix was removed for the add instruction [1].
> > >
> > > Signed-off-by: Francis Laniel <francis.laniel at amarulasolutions.com>
> > > Tested-by: Tony Dinh <mibodhi at gmail.com>
> > > [1] https://github.com/gcc-mirror/gcc/blob/4f181f9c7ee3efc509d185fdfda33be9018f1611/libgcc/config/arm/lib1funcs.S#L2156
> >
> > Thanks for the patch! I've added Tom, Pali, and Stefan.
>
> Looks good,
>
> Acked-by: Pali Rohár <pali at kernel.org>
>
> > I think we need to do some more testing for other boards that have
> > CONFIG_HAS_THUMB2 and CONFIG_SPL_SYS_THUMB_BUILD. My test target
> > (Marvell Armada 385 SoC) is somewhat broken right now. So it will take
> > some time for me to get that back running to run this test.

I've done some more testing with other boards. I'm seeing some
problems with LTO in gcc-12, but it is not related to this patch.

Acked-by:  Tony Dinh <mibodhi at gmail.com>

Thanks,
Tony

> >
> > All the best,
> > Tony
> >
> > > ---
> > >  arch/arm/lib/lib1funcs.S | 17 +++++++++++++++++
> > >  1 file changed, 17 insertions(+)
> > >
> > > diff --git a/arch/arm/lib/lib1funcs.S b/arch/arm/lib/lib1funcs.S
> > > index 7ff4446dd6..79cedc0aad 100644
> > > --- a/arch/arm/lib/lib1funcs.S
> > > +++ b/arch/arm/lib/lib1funcs.S
> > > @@ -424,4 +424,21 @@ ENTRY(__gnu_thumb1_case_uhi)
> > >         ret     lr
> > >  ENDPROC(__gnu_thumb1_case_uhi)
> > >  .popsection
> > > +
> > > +/* Taken and adapted from: https://github.com/gcc-mirror/gcc/blob/4f181f9c7ee3efc509d185fdfda33be9018f1611/libgcc/config/arm/lib1funcs.S#L2156 */
> > > +.pushsection .text.__gnu_thumb1_case_si, "ax"
> > > +ENTRY(__gnu_thumb1_case_si)
> > > +       push    {r0, r1}
> > > +       mov     r1, lr
> > > +       adds    r1, r1, #2      /* Align to word.  */
> > > +       lsrs    r1, r1, #2
> > > +       lsls    r0, r0, #2
> > > +       lsls    r1, r1, #2
> > > +       ldr     r0, [r1, r0]
> > > +       adds    r0, r0, r1
> > > +       mov     lr, r0
> > > +       pop     {r0, r1}
> > > +       mov     pc, lr          /* We know we were called from thumb code.  */
> > > +ENDPROC(__gnu_thumb1_case_si)
> > > +.popsection
> > >  #endif
> > > --
> > > 2.34.1
> > >