From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [v2] powerpc/perf: Fix kernel address leaks via Sampling registers
Date: Thu, 29 Mar 2018 01:13:26 +1100 (AEDT) [thread overview]
Message-ID: <40B8xL6Jblz9s0q@ozlabs.org> (raw)
In-Reply-To: <1521632426-30770-1-git-send-email-maddy@linux.vnet.ibm.com>
On Wed, 2018-03-21 at 11:40:24 UTC, Madhavan Srinivasan wrote:
> From: Michael Ellerman <mpe@ellerman.id.au>
>
> Current code in power_pmu_disable() does not clear the sampling
> registers like Sampling Instruction Address Register (SAIR) and
> Sampling Data Address Register (SDAR) after disabling the PMU.
> Since these are userspace readable and could contain kernel
> address, add code to explicitly clear the content of these registers.
> Patch also adds a "context synchronizing instruction" to enforce
> no further updates to these registers as mandated by PowerISA.
>
> "If an mtspr instruction is executed that changes the
> value of a Performance Monitor register other than
> SIAR, SDAR, and SIER, the change is not guaranteed
> to have taken effect until after a subsequent context
> synchronizing instruction has been executed (see
> Chapter 11. "Synchronization Requirements for Con-
> text Alterations" on page 1133)."
>
> Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/e1ebd0e5b9d0a10ba65e63a3514b6d
cheers
prev parent reply other threads:[~2018-03-28 14:13 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-21 11:40 [PATCH v2] powerpc/perf: Fix kernel address leaks via Sampling registers Madhavan Srinivasan
2018-03-21 11:40 ` [PATCH v2] powerpc/perf: Fix kernel address leak to userspace via BHRB buffer Madhavan Srinivasan
2018-03-28 14:13 ` [v2] " Michael Ellerman
2018-03-21 11:40 ` [PATCH v2] powerpc/perf: Fix the kernel address leak to userspace via SDAR Madhavan Srinivasan
2018-03-28 14:13 ` [v2] " Michael Ellerman
2018-03-28 14:13 ` Michael Ellerman [this message]
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