From: Russell Currey <ruscur@russell.cc>
To: Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@lists.ozlabs.org
Cc: rnsastry@linux.ibm.com
Subject: Re: [PATCH] powerpc/security: Fix Speculation_Store_Bypass reporting on Power10
Date: Thu, 18 May 2023 08:03:23 +1000 [thread overview]
Message-ID: <290087de21f20ea8d22db9fa0b8dfc7e2486ab28.camel@russell.cc> (raw)
In-Reply-To: <20230517074945.53188-1-mpe@ellerman.id.au>
On Wed, 2023-05-17 at 17:49 +1000, Michael Ellerman wrote:
> Nageswara reported that /proc/self/status was showing "vulnerable"
> for
> the Speculation_Store_Bypass feature on Power10, eg:
>
> $ grep Speculation_Store_Bypass: /proc/self/status
> Speculation_Store_Bypass: vulnerable
>
> But at the same time the sysfs files, and lscpu, were showing "Not
> affected".
>
> This turns out to simply be a bug in the reporting of the
> Speculation_Store_Bypass, aka. PR_SPEC_STORE_BYPASS, case.
>
> When SEC_FTR_STF_BARRIER was added, so that firmware could
> communicate
> the vulnerability was not present, the code in ssb_prctl_get() was
> not
> updated to check the new flag.
>
> So add the check for SEC_FTR_STF_BARRIER being disabled. Rather than
> adding the new check to the existing if block and expanding the
> comment
> to cover both cases, rewrite the three cases to be separate so they
> can
> be commented separately for clarity.
>
> Fixes: 84ed26fd00c5 ("powerpc/security: Add a security feature for
> STF barrier")
> Cc: stable@vger.kernel.org # v5.14+
> Reported-by: Nageswara R Sastry <rnsastry@linux.ibm.com>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Russell Currey <ruscur@russell.cc>
next prev parent reply other threads:[~2023-05-17 22:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-17 7:49 [PATCH] powerpc/security: Fix Speculation_Store_Bypass reporting on Power10 Michael Ellerman
2023-05-17 8:28 ` R Nageswara Sastry
2023-05-17 22:03 ` Russell Currey [this message]
2023-07-17 0:29 ` Michael Ellerman
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