From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] arm64: fix bug for reloading FPSIMD state after cpu power off
Date: Mon, 1 Sep 2014 12:56:40 +0100 [thread overview]
Message-ID: <20140901115640.GD24594@arm.com> (raw)
In-Reply-To: <20140901093427.GC608@arm.com>
On Mon, Sep 01, 2014 at 10:34:28AM +0100, Catalin Marinas wrote:
> On Mon, Sep 01, 2014 at 04:09:51AM +0100, Leo Yan wrote:
> > Now arm64 defers reloading FPSIMD state, but this optimization also
> > introduces the bug after cpu resume back from low power mode.
> >
> > The reason is after the cpu has been powered off, s/w need set the
> > cpu's fpsimd_last_state to NULL so that it will force to reload
> > FPSIMD state for the thread, otherwise there has the chance to meet
> > the condition for both the task's fpsimd_state.cpu field contains the
> > id of the current cpu, and the cpu's fpsimd_last_state per-cpu variable
> > points to the task's fpsimd_state, so finally kernel will skip to reload
> > the context during it return back to userland.
> >
> > Signed-off-by: Leo Yan <leoy@marvell.com>
>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
>
> (and cc'ing Will to pick it up since he's handling the 3.17 release)
Cheers for the CC; applied to fixes/core (I'll push out once I've run the
regression tests).
I aim to tag that branch tonight if we don't get any more fixes today.
Will
WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will.deacon@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Leo Yan <leoy@marvell.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"ard.biesheuvel@linaro.org" <ard.biesheuvel@linaro.org>
Subject: Re: [PATCH v2] arm64: fix bug for reloading FPSIMD state after cpu power off
Date: Mon, 1 Sep 2014 12:56:40 +0100 [thread overview]
Message-ID: <20140901115640.GD24594@arm.com> (raw)
In-Reply-To: <20140901093427.GC608@arm.com>
On Mon, Sep 01, 2014 at 10:34:28AM +0100, Catalin Marinas wrote:
> On Mon, Sep 01, 2014 at 04:09:51AM +0100, Leo Yan wrote:
> > Now arm64 defers reloading FPSIMD state, but this optimization also
> > introduces the bug after cpu resume back from low power mode.
> >
> > The reason is after the cpu has been powered off, s/w need set the
> > cpu's fpsimd_last_state to NULL so that it will force to reload
> > FPSIMD state for the thread, otherwise there has the chance to meet
> > the condition for both the task's fpsimd_state.cpu field contains the
> > id of the current cpu, and the cpu's fpsimd_last_state per-cpu variable
> > points to the task's fpsimd_state, so finally kernel will skip to reload
> > the context during it return back to userland.
> >
> > Signed-off-by: Leo Yan <leoy@marvell.com>
>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
>
> (and cc'ing Will to pick it up since he's handling the 3.17 release)
Cheers for the CC; applied to fixes/core (I'll push out once I've run the
regression tests).
I aim to tag that branch tonight if we don't get any more fixes today.
Will
next prev parent reply other threads:[~2014-09-01 11:56 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-01 3:09 [PATCH v2] arm64: fix bug for reloading FPSIMD state after cpu power off Leo Yan
2014-09-01 3:09 ` Leo Yan
2014-09-01 6:32 ` Ard Biesheuvel
2014-09-01 6:32 ` Ard Biesheuvel
2014-09-01 9:34 ` Catalin Marinas
2014-09-01 9:34 ` Catalin Marinas
2014-09-01 11:56 ` Will Deacon [this message]
2014-09-01 11:56 ` Will Deacon
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