[PATCH] arm64: Avoid breakage caused by .altmacro in fpsimd save/restore macros

[Dave P Martin]

On Thu, Jan 29, 2015 at 04:34:05PM +0000, Ard Biesheuvel wrote:
> On 29 January 2015 at 16:24, Dave Martin <Dave.Martin at arm.com> wrote:
> > Alternate macro mode is not a property of a macro definition, but a
> > gas runtime state that alters the way macros are expanded for ever
> > after (until .noaltmacro is seen).
> >
> > This means that subsequent assembly code that calls other macros can
> > break if fpsimdmacros.h is included.
> >
> > Since these instruction sequences are simple (if dull -- but in a
> > good way), this patch solves the problem by simply expanding the
> > .irp loops.  The pre-existing fpsimd_{save,restore} macros weren't
> > rolled with .irp anyway and the sequences affected are short, so
> > this change restores consistency at little cost.
> >
> > Signed-off-by: Dave Martin <Dave.Martin at arm.com>
> 
> Acked-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>

Thanks

(Also, apologies for accidentally missing you from cc)

Cheers
---Dave

> 
> > ---
> >  arch/arm64/include/asm/fpsimdmacros.h |   43 ++++++++++++++++++++++++---------
> >  1 file changed, 32 insertions(+), 11 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h
> > index 007618b..a2daf12 100644
> > --- a/arch/arm64/include/asm/fpsimdmacros.h
> > +++ b/arch/arm64/include/asm/fpsimdmacros.h
> > @@ -76,7 +76,6 @@
> >         fpsimd_restore_fpcr x\tmpnr, \state
> >  .endm
> >
> > -.altmacro
> >  .macro fpsimd_save_partial state, numnr, tmpnr1, tmpnr2
> >         mrs     x\tmpnr1, fpsr
> >         str     w\numnr, [\state, #8]
> > @@ -86,11 +85,22 @@
> >         add     \state, \state, x\numnr, lsl #4
> >         sub     x\tmpnr1, x\tmpnr1, x\numnr, lsl #1
> >         br      x\tmpnr1
> > -       .irp    qa, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 0
> > -       .irp    qb, %(qa + 1)
> > -       stp     q\qa, q\qb, [\state, # -16 * \qa - 16]
> > -       .endr
> > -       .endr
> > +       stp     q30, q31, [\state, #-16 * 30 - 16]
> > +       stp     q28, q29, [\state, #-16 * 28 - 16]
> > +       stp     q26, q27, [\state, #-16 * 26 - 16]
> > +       stp     q24, q25, [\state, #-16 * 24 - 16]
> > +       stp     q22, q23, [\state, #-16 * 22 - 16]
> > +       stp     q20, q21, [\state, #-16 * 20 - 16]
> > +       stp     q18, q19, [\state, #-16 * 18 - 16]
> > +       stp     q16, q17, [\state, #-16 * 16 - 16]
> > +       stp     q14, q15, [\state, #-16 * 14 - 16]
> > +       stp     q12, q13, [\state, #-16 * 12 - 16]
> > +       stp     q10, q11, [\state, #-16 * 10 - 16]
> > +       stp     q8, q9, [\state, #-16 * 8 - 16]
> > +       stp     q6, q7, [\state, #-16 * 6 - 16]
> > +       stp     q4, q5, [\state, #-16 * 4 - 16]
> > +       stp     q2, q3, [\state, #-16 * 2 - 16]
> > +       stp     q0, q1, [\state, #-16 * 0 - 16]
> >  0:
> >  .endm
> >
> > @@ -103,10 +113,21 @@
> >         add     \state, \state, x\tmpnr2, lsl #4
> >         sub     x\tmpnr1, x\tmpnr1, x\tmpnr2, lsl #1
> >         br      x\tmpnr1
> > -       .irp    qa, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 0
> > -       .irp    qb, %(qa + 1)
> > -       ldp     q\qa, q\qb, [\state, # -16 * \qa - 16]
> > -       .endr
> > -       .endr
> > +       ldp     q30, q31, [\state, #-16 * 30 - 16]
> > +       ldp     q28, q29, [\state, #-16 * 28 - 16]
> > +       ldp     q26, q27, [\state, #-16 * 26 - 16]
> > +       ldp     q24, q25, [\state, #-16 * 24 - 16]
> > +       ldp     q22, q23, [\state, #-16 * 22 - 16]
> > +       ldp     q20, q21, [\state, #-16 * 20 - 16]
> > +       ldp     q18, q19, [\state, #-16 * 18 - 16]
> > +       ldp     q16, q17, [\state, #-16 * 16 - 16]
> > +       ldp     q14, q15, [\state, #-16 * 14 - 16]
> > +       ldp     q12, q13, [\state, #-16 * 12 - 16]
> > +       ldp     q10, q11, [\state, #-16 * 10 - 16]
> > +       ldp     q8, q9, [\state, #-16 * 8 - 16]
> > +       ldp     q6, q7, [\state, #-16 * 6 - 16]
> > +       ldp     q4, q5, [\state, #-16 * 4 - 16]
> > +       ldp     q2, q3, [\state, #-16 * 2 - 16]
> > +       ldp     q0, q1, [\state, #-16 * 0 - 16]
> >  0:
> >  .endm
> > --
> > 1.7.10.4
> >
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>