From: Valentine <vbarshak@ru•mvista.com>
To: Benjamin Herrenschmidt <benh@kernel•crashing.org>
Cc: olof@lixom•net, linuxppc-dev@ozlabs•org, paulus@samba•org
Subject: Re: [PATCH v3] powerpc/ppc64: Use preempt_schedule_irq instead of preempt_schedule
Date: Thu, 29 Oct 2009 00:28:01 +0300 [thread overview]
Message-ID: <4AE8B761.3090902@ru.mvista.com> (raw)
In-Reply-To: <1256761844.26770.2.camel@pasglop>
Benjamin Herrenschmidt wrote:
> On Wed, 2009-10-28 at 22:19 +0300, Valentine wrote:
>
>> I'm just not sure that we need to clear HARDIRQEN here, since we don't
>> really hard-disable the the interrupts.
>
> We do, or rather, we come in with the interrupts hard disabled, no ?
Yes, looks like the interrupts are disabled at this point (before
preempt_schedule_irq) most of the times, but we don't hard-disable them
here. We just soft-disable them to make preempt_schedule_irq happy. Even
if an interrupt fires, it will be hard-disabled and the hardirq flag
will be cleared by the exception handler right away. I just think that
there's no need to clear hardirq flag if we don't clear MSR_EE.
Thanks,
Val.
>
> Ben.
>
>> Thanks,
>> Val.
>>
>>> + TRACE_DISABLE_INTS
>>> +
>>> + /* Call the scheduler with soft IRQs off */
>>> +1: bl .preempt_schedule_irq
>>> +
>>> + /* Hard-disable interrupts again (and update PACA) */
>>> #ifdef CONFIG_PPC_BOOK3E
>>> - wrteei 1
>>> - bl .preempt_schedule
>>> wrteei 0
>>> #else
>>> - ori r10,r10,MSR_EE
>>> - mtmsrd r10,1 /* reenable interrupts */
>>> - bl .preempt_schedule
>>> mfmsr r10
>>> - clrrdi r9,r1,THREAD_SHIFT
>>> - rldicl r10,r10,48,1 /* disable interrupts again */
>>> + rldicl r10,r10,48,1
>>> rotldi r10,r10,16
>>> mtmsrd r10,1
>>> #endif /* CONFIG_PPC_BOOK3E */
>>> + li r0,0
>>> + stb r0,PACAHARDIRQEN(r13)
>>> +
>>> + /* Re-test flags and eventually loop */
>>> + clrrdi r9,r1,THREAD_SHIFT
>>> ld r4,TI_FLAGS(r9)
>>> andi. r0,r4,_TIF_NEED_RESCHED
>>> bne 1b
>>> b restore
>>>
>>> user_work:
>>> -#endif
>>> +#endif /* CONFIG_PREEMPT */
>>> +
>>> /* Enable interrupts */
>>> #ifdef CONFIG_PPC_BOOK3E
>>> wrteei 1
>
>
next prev parent reply other threads:[~2009-10-28 21:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-19 18:28 [PATCH] [RFC] PowerPC64: Use preempt_schedule_irq instead of preempt_schedule when returning from exceptions Valentine Barshak
2009-10-26 23:55 ` Benjamin Herrenschmidt
2009-10-27 5:41 ` [PATCH v3] powerpc/ppc64: Use preempt_schedule_irq instead of preempt_schedule Benjamin Herrenschmidt
2009-10-28 19:19 ` Valentine
2009-10-28 20:30 ` Benjamin Herrenschmidt
2009-10-28 21:28 ` Valentine [this message]
2009-10-28 21:37 ` Benjamin Herrenschmidt
2009-10-28 22:49 ` Valentine
2009-10-29 0:49 ` Benjamin Herrenschmidt
2009-11-06 22:38 ` Valentine
2009-11-06 22:49 ` Benjamin Herrenschmidt
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