Re: [PATCH v3] powerpc/kernel/sysfs: Export ldbar spr to sysfs

[Anju T Sudhakar]

Hi,


On Tuesday 06 March 2018 04:35 PM, Michael Ellerman wrote:
> Anju T Sudhakar <anju@xxxxxxxxxxxxxxxxxx> writes:
>
> > diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
> > index 4437c70..caefb64 100644
> > --- a/arch/powerpc/kernel/sysfs.c
> > +++ b/arch/powerpc/kernel/sysfs.c
> > @@ -757,6 +759,9 @@ static int register_cpu_online(unsigned int cpu)
> >   			device_create_file(s, &pmc_attrs[i]);
> >   
> >   #ifdef CONFIG_PPC64
> > +	if (cpu_has_feature(CPU_FTR_ARCH_300))
> > +		device_create_file(s, &dev_attr_ldbar);
> Is this register readable in supervisor state?

This is a nice catch, thanks. :)
The guest kernel can not access the register, it is only readable in the 
hypervisor state.
I will resend the patch with a condition check so that this spr will not 
get registered for guest kernel.


Regards,
Anju
> cheers