Re: [PATCH] LoongArch: Align FPU register state to 32 bytes

[Huacai Chen]

On Tue, Apr 14, 2026 at 4:20 PM Huacai Chen <chenhuacai@xxxxxxxxxx> wrote:
>
> On Sat, Apr 11, 2026 at 9:10 PM Huacai Chen <chenhuacai@xxxxxxxxxx> wrote:
> >
> > Applied, thanks.
> I'm sorry, I reverted this patch because it breaks the partial copy
> optimization in arch_dup_task_struct().
Fixed as this:
https://github.com/chenhuacai/linux/commit/c1365bc97d609438809d5d44d338adfc09767d6f

Huacai

>
> Huacai
>
> >
> > Huacai
> >
> > On Mon, Mar 30, 2026 at 5:49 PM Lisa Robinson <lisa@bytefly.space> wrote:
> > >
> > > Move fpr to the beginning of struct loongarch_fpu so it is naturally
> > > aligned to FPU_ALIGN (32 bytes), improving 256-bit SIMD (LASX) context
> > > switch performance.
> > >
> > > Signed-off-by: Lisa Robinson <lisa@bytefly.space>
> > > ---
> > >  arch/loongarch/include/asm/processor.h | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/arch/loongarch/include/asm/processor.h b/arch/loongarch/include/asm/processor.h
> > > index c3bc44b5f5b3..ce8b953f8c79 100644
> > > --- a/arch/loongarch/include/asm/processor.h
> > > +++ b/arch/loongarch/include/asm/processor.h
> > > @@ -80,10 +80,10 @@ BUILD_FPR_ACCESS(32)
> > >  BUILD_FPR_ACCESS(64)
> > >
> > >  struct loongarch_fpu {
> > > +       union fpureg    fpr[NUM_FPU_REGS];
> > >         uint64_t        fcc;    /* 8x8 */
> > >         uint32_t        fcsr;
> > >         uint32_t        ftop;
> > > -       union fpureg    fpr[NUM_FPU_REGS];
> > >  };
> > >
> > >  struct loongarch_lbt {
> > > --
> > > 2.53.0
> > >