From: jamie@shareable.org (Jamie Lokier)
To: linux-arm-kernel@lists.infradead.org
Subject: LDREX/STREX and pre-emption on SMP hardware
Date: Fri, 21 Aug 2009 16:50:11 +0100 [thread overview]
Message-ID: <20090821155011.GB8583@shareable.org> (raw)
In-Reply-To: <1250869355.10642.10.camel@pc1117.cambridge.arm.com>
Catalin Marinas wrote:
> On Fri, 2009-08-21 at 16:07 +0100, Richard Crewe wrote:
> > Section A2.9.3 of the ARM architecture ref. manual seems to imply that
> > ldrex/strex instruction pairs won't work correctly if they are nested
> > due to pre-emption.
> >
> > Should a strex instruction be added to the low-level interrupt handler
> > or should all ldrex/strex instruction pairs be protected from
> > pre-emption by disabling interrupts?
>
> There is no need to since preemption means rescheduling which implies a
> call to the __switch_to function in entry-armv.S. This function clears
> the exclusive monitor state explicitly.
What about when an interrupt handler uses ldrex/strex? There is no
call to __switch_to.
-- Jamie
next prev parent reply other threads:[~2009-08-21 15:50 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-21 15:07 LDREX/STREX and pre-emption on SMP hardware Richard Crewe
2009-08-21 15:42 ` Catalin Marinas
2009-08-21 15:50 ` Jamie Lokier [this message]
2009-08-21 15:58 ` Catalin Marinas
2009-08-21 21:29 ` David Xiao
2009-08-24 15:44 ` Catalin Marinas
2009-08-24 17:14 ` David Xiao
2009-08-24 17:41 ` Catalin Marinas
2009-08-24 18:59 ` David Xiao
2009-09-14 1:43 ` Jamie Lokier
2009-09-14 8:53 ` Catalin Marinas
2009-09-14 10:00 ` Russell King - ARM Linux
2009-09-14 10:06 ` Catalin Marinas
2009-09-14 11:47 ` Catalin Marinas
2009-09-14 12:21 ` Catalin Marinas
2009-09-14 12:43 ` Bill Gatliff
2009-09-14 12:57 ` Catalin Marinas
2009-09-14 19:30 ` Bill Gatliff
2009-09-14 14:09 ` Russell King - ARM Linux
2009-09-14 14:21 ` Russell King - ARM Linux
2009-09-14 14:26 ` Catalin Marinas
2009-09-14 15:35 ` Catalin Marinas
2009-09-14 23:16 ` Jamie Lokier
2009-09-14 14:23 ` Russell King - ARM Linux
2009-09-14 14:29 ` Catalin Marinas
2009-09-18 20:20 ` Russell King - ARM Linux
2009-09-18 22:51 ` Catalin Marinas
2009-08-24 21:12 ` Jamie Lokier
2009-08-25 8:33 ` Catalin Marinas
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