2018-03-06 11:08:04

by Michael Ellerman

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

Anju T Sudhakar <[email protected]> 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?

cheers

2018-03-13 05:44:41

by Anju T Sudhakar

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

Hi,


On Tuesday 06 March 2018 04:35 PM, Michael Ellerman wrote:
> Anju T Sudhakar <[email protected]> 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
>