[RFC PATCH] powerpc/fsl: Add barrier_nospec implementation for NXP PowerPC Book E

[Diana Madalina Craciun]

On 6/1/2018 1:40 PM, Michael Ellerman wrote:
> Scott Wood <oss at buserror.net> writes:
>
>> On Thu, 2018-05-31 at 14:35 +0000, Diana Madalina Craciun wrote:
>>> On 5/31/2018 5:21 PM, Michael Ellerman wrote:
>>>> We can add a nospectre_v1 command line option if necessary.
>>> What about nobarrier_nospec (or similar) instead of nospectre_v1 command
>>> line? We are not disabling all the v1 mitigations, the masking part will
>>> remain unchanged.
>> I think nospectre_v1 makes more sense as it's about the user's intentions
>> rather than the implementation.  The user is giving the kernel permission to
>> not defend against spectre v1, and it's up to the implementation which
>> mitigations (if any) to disable in response to that, same as any other
>> optimization.
> Yeah I agree. We also have `nospectre_v2` on x86/s390 so I think keeping
> consistency with that is a must.
>
> cheers
>
OK

Diana