[PATCH v4 4/6] powerpc/fsl: Enable cpu vulnerabilities reporting for NXP PPC BOOK3E

[Diana Madalina Craciun]

On 7/19/2018 3:05 PM, Michael Ellerman wrote:
> LEROY Christophe <christophe.leroy at c-s.fr> writes:
>> Diana Madalina Craciun <diana.craciun at nxp.com> a écrit :
>>> On 7/17/2018 7:47 PM, LEROY Christophe wrote:
>>>> Diana Craciun <diana.craciun at nxp.com> a écrit :
>>>>> The NXP PPC Book3E platforms are not vulnerable to meltdown and
>>>>> Spectre v4, so make them PPC_BOOK3S_64 specific.
>>>>>
>>>>> Signed-off-by: Diana Craciun <diana.craciun at nxp.com>
>>>>> ---
>>>>> History:
>>>>>
>>>>> v2-->v3
>>>>> - used the existing functions for spectre v1/v2
>>>>>
>>>>>  arch/powerpc/Kconfig           | 7 ++++++-
>>>>>  arch/powerpc/kernel/security.c | 2 ++
>>>>>  2 files changed, 8 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>>>>> index 9f2b75f..116c953 100644
>>>>> --- a/arch/powerpc/Kconfig
>>>>> +++ b/arch/powerpc/Kconfig
>>>>> @@ -165,7 +165,7 @@ config PPC
>>>>>  	select GENERIC_CLOCKEVENTS_BROADCAST	if SMP
>>>>>  	select GENERIC_CMOS_UPDATE
>>>>>  	select GENERIC_CPU_AUTOPROBE
>>>>> -	select GENERIC_CPU_VULNERABILITIES	if PPC_BOOK3S_64
>>>>> +	select GENERIC_CPU_VULNERABILITIES	if PPC_NOSPEC
>>>> I don't understand.  You say this patch is to make something specific
>>>> to book3s64 specific, and you are creating a new config param that
>>>> make things less specific
>>>>
>>>> Christophe
>>> In order to enable the vulnerabilities reporting on NXP socs I need to
>>> enable them for PPC_FSL_BOOK3E. So they will be enabled for both
>>> PPC_FSL_BOOK3E and PPC_BOOK3S_64. This is the reason for adding the
>>> Kconfig. However this will enable: spectre v1/v2 and meltdown. NXP socs
>>> are not vulnerable to meltdown, so I made the meltdown reporting
>>> PPC_BOOK3S_64 specific. I guess I can have the PPC_NOSPEC definition in
>>> a separate patch to be more clear.
>> Yes you can. Or keep it as a single patch and add the details you gave  
>> me in the patch description.
> Yeah I think the patch is fine, but the change log is a bit short on detail.
>
> If you just send me a new change log I can fold it in.
>
> cheers
>
Thanks! This is the new change log:

"The Spectre/Meltdown vulnerabilities will be enabled for both
PPC_FSL_BOOK3E and PPC_BOOK3S_64. In order to avoid a complicated ifdef
we add a new Kconfig (PPC_NOSPEC) to select the common code between
BOOK3S_64 and FSL_BOOK3E. However, the NXP platforms are not vulnerable
to Meltdown, so make the Meltdown vulnerability reporting PPC_BOOK3S_64
specific."

Regards,

Diana