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From: Peter Zijlstra <peterz@infradead.org>
To: Paul Mundt <lethal@linux-sh.org>
Cc: David Miller <davem@davemloft.net>,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	sparclinux@vger.kernel.org
Subject: Re: [PATCH 1/4] kernel: local_irq_{save,restore}_nmi()
Date: Fri, 04 Jun 2010 09:35:15 +0200	[thread overview]
Message-ID: <1275636915.27810.38912.camel@twins> (raw)
In-Reply-To: <20100604050347.GE31868@linux-sh.org>

On Fri, 2010-06-04 at 14:03 +0900, Paul Mundt wrote:
> On Fri, Apr 09, 2010 at 04:01:35PM -0700, David Miller wrote:
> > 
> > Provide local_irq_{save,restore}_nmi() which will allow us to help
> > architectures that implement NMIs using IRQ priorities like SPARC64
> > does.
> > 
> > Sparc uses IRQ prio 15 for NMIs and implements local_irq_disable() as
> > disable <= 14. However if you do that while inside an NMI you re-
> > enable the NMI priority again, causing all kinds of fun.
> > 
> > A more solid implementation would first check the disable level and
> > never lower it, however that is more costly and would slow down the
> > rest of the kernel for no particular reason.
> > 
> > Therefore introduce local_irq_save_nmi() which can implement this
> > slower but more solid scheme and dis-allow local_irq_save() from NMI
> > context.
> > 
> > Suggested-by: David Miller <davem@davemloft.net>
> > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > Signed-off-by: David S. Miller <davem@davemloft.net>
> 
> Are there any updates for this patch series? I would like to make use of
> this on SH as well, but it seems these haven't hit upstream yet.

Dave found a better solution, see:

  b4f4372f96e0573d752d9e45beda02fabf716cc8
  0c25e9e6cbe7b233bb91d14d0e2c258bf8e6ec83
  c011f80ba0912486fe51dd2b3f71d9b33a151188



  reply	other threads:[~2010-06-04  7:35 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-09 23:01 [PATCH 1/4] kernel: local_irq_{save,restore}_nmi() David Miller
2010-04-09 23:01 ` David Miller
2010-06-04  5:03 ` Paul Mundt
2010-06-04  7:35   ` Peter Zijlstra [this message]
2010-06-04  7:35     ` Peter Zijlstra

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