From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: David Gibson <david@gibson.dropbear.id.au>, paulus@samba.org
Cc: jasowang@redhat.com, linuxppc-dev@lists.ozlabs.org,
thuth@redhat.com, David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [RFC] arch/powerpc: Turn off irqs in switch_mm()
Date: Tue, 25 Apr 2017 08:47:35 +1000 (AEST) [thread overview]
Message-ID: <3wBhLc21L4z9s8Y@ozlabs.org> (raw)
In-Reply-To: <20170419063826.1678-1-david@gibson.dropbear.id.au>
On Wed, 2017-04-19 at 06:38:26 UTC, David Gibson wrote:
> There seems to be a mismatch in expectations between the powerpc arch code
> and the generic (and x86) code in terms of the irq state when switch_mm()
> is called.
>
> powerpc expects irqs to already be (soft) disabled when switch_mm() is
> called, as made clear in the commit message of 9c1e105 "powerpc: Allow
> perf_counters to access user memory at interrupt time".
>
> That seems to be true when it's called from the schedule, but not for
> use_mm(). This becomes clear when looking at the x86 code paths for
> switch_mm(). There, switch_mm() itself disable irqs, with a
> switch_mm_irqs_off() variant which expects that to be already done.
>
> This patch addresses the problem, making the powerpc code mirror the x86
> code.
>
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/9765ad134a00a01cbcc69c78ff6def
cheers
prev parent reply other threads:[~2017-04-24 22:47 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-19 6:38 [RFC] arch/powerpc: Turn off irqs in switch_mm() David Gibson
2017-04-24 22:47 ` Michael Ellerman [this message]
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