From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Paul Mackerras <paulus@samba.org>
Cc: David Howells <dhowells@redhat.com>,
torvalds@osdl.org, akpm@osdl.org, mingo@redhat.com,
linux-arch@vger.kernel.org, linuxppc64-dev@ozlabs.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Document Linux's memory barriers
Date: Wed, 08 Mar 2006 22:05:14 +0000 [thread overview]
Message-ID: <1141855514.10606.10.camel@localhost.localdomain> (raw)
In-Reply-To: <17423.20862.764098.732463@cargo.ozlabs.ibm.com>
On Iau, 2006-03-09 at 08:49 +1100, Paul Mackerras wrote:
> If the device accesses to memory are in response to an MMIO store,
> then the code needs an explicit wmb() between the memory stores and
> the MMIO store. Disabling interrupts isn't going to help here because
> the device doesn't see the CPU interrupt enable state.
Interrupts are themselves entirely asynchronous anyway. The following
can occur on SMP Pentium-PIII.
Device
Raise IRQ
CPU
writel(MASK_IRQ, &dev->ctrl);
readl(&dev->ctrl);
IRQ arrives
CPU specific IRQ masking is synchronous, but IRQ delivery is not,
including IPI delivery (which is asynchronous and not guaranteed to
occur only once per IPI but can be replayed in obscure cases on x86).
next prev parent reply other threads:[~2006-03-08 21:59 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-07 17:40 [PATCH] Document Linux's memory barriers David Howells
2006-03-07 10:34 ` Andi Kleen
2006-03-07 18:30 ` David Howells
2006-03-07 11:13 ` Andi Kleen
2006-03-07 19:24 ` David Howells
2006-03-07 18:46 ` Jesse Barnes
2006-03-07 19:23 ` Bryan O'Sullivan
2006-03-07 11:57 ` Andi Kleen
2006-03-07 20:01 ` Jesse Barnes
2006-03-07 21:14 ` Bryan O'Sullivan
2006-03-07 21:24 ` Andi Kleen
2006-03-08 0:36 ` Alan Cox
2006-03-08 0:35 ` Alan Cox
2006-03-07 18:40 ` Alan Cox
2006-03-07 18:54 ` linux-os (Dick Johnson)
2006-03-07 19:06 ` Matthew Wilcox
2006-03-07 19:15 ` linux-os (Dick Johnson)
2006-03-07 19:33 ` Alan Cox
2006-03-07 20:09 ` David Howells
2006-03-08 0:32 ` Alan Cox
2006-03-08 8:25 ` Duncan Sands
2006-03-08 22:06 ` Paul Mackerras
2006-03-08 22:24 ` David S. Miller
2006-03-08 22:31 ` Linus Torvalds
2006-03-08 22:42 ` Alan Cox
2006-03-08 2:07 ` Nick Piggin
2006-03-08 3:10 ` Paul Mackerras
2006-03-08 3:30 ` Linus Torvalds
2006-03-08 12:34 ` David Howells
2006-03-08 16:40 ` Bryan O'Sullivan
2006-03-08 7:41 ` Nick Piggin
2006-03-08 13:19 ` David Howells
2006-03-08 21:49 ` Paul Mackerras
2006-03-08 22:05 ` Alan Cox [this message]
2006-03-08 14:37 ` [PATCH] Document Linux's memory barriers [try #2] David Howells
2006-03-08 14:55 ` Alan Cox
2006-03-08 15:41 ` Matthew Wilcox
2006-03-08 17:19 ` David Howells
2006-03-08 22:10 ` Paul Mackerras
2006-03-08 23:08 ` Ivan Kokshaysky
2006-03-09 1:01 ` Paul Mackerras
2006-03-09 16:02 ` Ivan Kokshaysky
2006-03-08 17:04 ` David Howells
2006-03-08 17:36 ` Alan Cox
2006-03-08 18:35 ` David Howells
2006-03-08 18:45 ` Alan Cox
2006-03-08 18:59 ` David Howells
2006-03-08 11:38 ` Andi Kleen
2006-03-08 19:08 ` David Howells
2006-03-08 19:26 ` Linus Torvalds
2006-03-08 19:31 ` David Howells
2006-03-09 0:35 ` Paul Mackerras
2006-03-09 0:54 ` Linus Torvalds
2006-03-09 1:08 ` Paul Mackerras
2006-03-09 1:27 ` Linus Torvalds
2006-03-09 2:38 ` Nick Piggin
2006-03-09 3:45 ` Paul Mackerras
2006-03-09 4:36 ` Jesse Barnes
2006-03-09 7:41 ` Paul Mackerras
2006-03-09 5:38 ` Linus Torvalds
2006-03-09 12:27 ` David Howells
2006-03-09 11:44 ` Michael Buesch
2006-03-09 4:34 ` Jesse Barnes
2006-03-09 4:43 ` Paul Mackerras
2006-03-09 10:05 ` Jes Sorensen
2006-03-09 0:55 ` Jesse Barnes
2006-03-09 1:57 ` Paul Mackerras
2006-03-09 4:26 ` Jesse Barnes
2006-03-08 19:40 ` Matthew Wilcox
2006-03-09 0:37 ` Paul Mackerras
2006-03-09 0:59 ` Jesse Barnes
2006-03-09 1:36 ` Paul Mackerras
2006-03-09 4:18 ` Jesse Barnes
2006-03-08 19:54 ` Jesse Barnes
2006-03-08 20:02 ` Alan Cox
2006-03-08 22:01 ` Paul Mackerras
2006-03-08 22:23 ` David S. Miller
2006-03-08 19:37 ` [PATCH] Document Linux's memory barriers [try #3] David Howells
2006-03-09 14:01 ` David Howells
2006-03-08 16:18 ` [PATCH] Document Linux's memory barriers Pavel Machek
2006-03-08 20:16 ` David Howells
2006-03-08 22:01 ` Alan Cox
2006-03-09 11:41 ` David Howells
2006-03-09 12:28 ` Alan Cox
2006-03-09 13:02 ` David Howells
2006-03-09 16:32 ` Linus Torvalds
2006-03-09 17:39 ` David Howells
2006-03-09 17:54 ` Linus Torvalds
2006-03-09 17:56 ` Linus Torvalds
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