Re: [PATCH v12 04/31] arm64/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT

[Laurent Dufour]

Le 16/04/2019 Ã 16:27, Mark Rutland a ÃcritÂ:
> On Tue, Apr 16, 2019 at 03:44:55PM +0200, Laurent Dufour wrote:
> > From: Mahendran Ganesh <opensource.ganesh@xxxxxxxxx>
> >
> > Set ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT for arm64. This
> > enables Speculative Page Fault handler.
> >
> > Signed-off-by: Ganesh Mahendran <opensource.ganesh@xxxxxxxxx>
>
> This is missing your S-o-B.

You're right, I missed that...

> The first patch noted that the ARCH_SUPPORTS_* option was there because
> the arch code had to make an explicit call to try to handle the fault
> speculatively, but that isn't addeed until patch 30.
>
> Why is this separate from that code?

Andrew was recommended this a long time ago for bisection purpose. This 
allows to build the code with CONFIG_SPECULATIVE_PAGE_FAULT before the 
code that trigger the spf handler is added to the per architecture's code.

Thanks,
Laurent.

> Thanks,
> Mark.
>
> > ---
> >   arch/arm64/Kconfig | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index 870ef86a64ed..8e86934d598b 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -174,6 +174,7 @@ config ARM64
> >   	select SWIOTLB
> >   	select SYSCTL_EXCEPTION_TRACE
> >   	select THREAD_INFO_IN_TASK
> > +	select ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT
> >   	help
> >   	  ARM 64-bit (AArch64) Linux support.
> >   
> > --
> > 2.21.0