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From: Michael Ellerman <mpe@ellerman.id.au>
To: Scott Wood <oss@buserror.net>,
	Diana Madalina Craciun <diana.craciun@nxp.com>,
	"linuxppc-dev\@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Cc: Leo Li <leoyang.li@nxp.com>
Subject: Re: [RFC PATCH] powerpc/fsl: Add barrier_nospec implementation for NXP PowerPC Book E
Date: Fri, 01 Jun 2018 20:40:11 +1000	[thread overview]
Message-ID: <87vab23i44.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <1527804215.30674.35.camel@buserror.net>

Scott Wood <oss@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

  reply	other threads:[~2018-06-01 10:40 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1526973031-9543-1-git-send-email-diana.craciun@nxp.com>
2018-05-22 20:29 ` [RFC PATCH] powerpc/fsl: Add barrier_nospec implementation for NXP PowerPC Book E Scott Wood
2018-05-29 15:22   ` Diana Madalina Craciun
2018-05-29 19:14     ` Scott Wood
2018-05-30 15:09       ` Diana Madalina Craciun
2018-05-31 14:21       ` Michael Ellerman
2018-05-31 14:35         ` Diana Madalina Craciun
2018-05-31 22:03           ` Scott Wood
2018-06-01 10:40             ` Michael Ellerman [this message]
2018-06-01 14:58               ` Diana Madalina Craciun
2018-05-23  8:56 ` [RESEND RFC " Diana Craciun

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