Re: [PATCH] arm64: entry: Save some nops when CONFIG_ARM64_PSEUDO_NMI is not set

[He Ying]

在 2022/1/19 17:35, Mark Rutland 写道:
> On Wed, Jan 19, 2022 at 02:40:58PM +0800, He Ying wrote:
> > Hi all,
> >
> > Ping. Any comments?
> The patch looks fine, but as it's the middle of the merge window people
> are busy and unlikely to look at this for the next few days.
>
> Generally it's a good idea to wait until rc1 or rc2, rebase atop that,
> and post the updated patch. Stuff like this usually gets queued around
> rc3/rc4 time.
OK. Thanks for your comment.
> > 锟斤拷 2022/1/12 11:24, He Ying 写锟斤拷:
> > > Arm64 pseudo-NMI feature code brings some additional nops
> > > when CONFIG_ARM64_PSEUDO_NMI is not set, which is not
> > > necessary. So add necessary ifdeffery to avoid it.
> > >
> > > Signed-off-by: He Ying <heying24@xxxxxxxxxx>
> FWIW:
>
> Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
>
> Mark.
>
> > > ---
> > >    arch/arm64/kernel/entry.S | 4 ++++
> > >    1 file changed, 4 insertions(+)
> > >
> > > diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> > > index 2f69ae43941d..ffc32d3d909a 100644
> > > --- a/arch/arm64/kernel/entry.S
> > > +++ b/arch/arm64/kernel/entry.S
> > > @@ -300,6 +300,7 @@ alternative_else_nop_endif
> > >    	str	w21, [sp, #S_SYSCALLNO]
> > >    	.endif
> > > +#ifdef CONFIG_ARM64_PSEUDO_NMI
> > >    	/* Save pmr */
> > >    alternative_if ARM64_HAS_IRQ_PRIO_MASKING
> > >    	mrs_s	x20, SYS_ICC_PMR_EL1
> > > @@ -307,6 +308,7 @@ alternative_if ARM64_HAS_IRQ_PRIO_MASKING
> > >    	mov	x20, #GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET
> > >    	msr_s	SYS_ICC_PMR_EL1, x20
> > >    alternative_else_nop_endif
> > > +#endif
> > >    	/* Re-enable tag checking (TCO set on exception entry) */
> > >    #ifdef CONFIG_ARM64_MTE
> > > @@ -330,6 +332,7 @@ alternative_else_nop_endif
> > >    	disable_daif
> > >    	.endif
> > > +#ifdef CONFIG_ARM64_PSEUDO_NMI
> > >    	/* Restore pmr */
> > >    alternative_if ARM64_HAS_IRQ_PRIO_MASKING
> > >    	ldr	x20, [sp, #S_PMR_SAVE]
> > > @@ -339,6 +342,7 @@ alternative_if ARM64_HAS_IRQ_PRIO_MASKING
> > >    	dsb	sy				// Ensure priority change is seen by redistributor
> > >    .L__skip_pmr_sync\@:
> > >    alternative_else_nop_endif
> > > +#endif
> > >    	ldp	x21, x22, [sp, #S_PC]		// load ELR, SPSR
> .