From: "tiejun.chen" <tiejun.chen@windriver.com>
To: Scott Wood <scottwood@freescale.com>
Cc: linuxppc-dev@lists.ozlabs.org, agraf@suse.de,
kvm-ppc@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [v1][PATCH 1/1] KVM: PPC: disable preemption when using hard_irq_disable()
Date: Thu, 11 Jul 2013 11:00:33 +0800 [thread overview]
Message-ID: <51DE1FD1.90609@windriver.com> (raw)
In-Reply-To: <1373483740.8183.223@snotra>
On 07/11/2013 03:15 AM, Scott Wood wrote:
> On 07/10/2013 01:02:19 AM, Tiejun Chen wrote:
>> We should ensure the preemption cannot occur while calling get_paca()
>> insdide hard_irq_disable(), otherwise the paca_struct may be the
>> wrong one just after. And btw, we may update timing stats in this case.
>
> The soft-ee mechanism depends on accessing the PACA directly via r13 to avoid
> this. We probably should be using inline asm to read was_enabled rather than
Yes.
> hoping the compiler doesn't do anything silly.
Do you recommend I should directly replace get_paca() with local_paca inside
hard_irq_disable()?
#define hard_irq_disable() do { \
u8 _was_enabled = get_paca()->soft_enabled; \
-> u8 _was_enabled = local_paca->soft_enabled;
But is this safe for all scenarios?
Tiejun
next prev parent reply other threads:[~2013-07-11 2:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1373436139-27998-1-git-send-email-tiejun.chen@windriver.com>
2013-07-10 19:15 ` [v1][PATCH 1/1] KVM: PPC: disable preemption when using hard_irq_disable() Scott Wood
2013-07-11 3:00 ` tiejun.chen [this message]
2013-07-11 14:13 ` Scott Wood
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