From: Paul Mackerras <paulus@samba.org>
To: Russell King <rmk+lkml@arm.linux.org.uk>
Cc: Segher Boessenkool <segher@kernel.crashing.org>,
Christoph Lameter <clameter@sgi.com>,
heiko.carstens@de.ibm.com, horms@verge.net.au,
linux-kernel@vger.kernel.org,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
ak@suse.de, netdev@vger.kernel.org, cfriesen@nortel.com,
akpm@linux-foundation.org, rpjday@mindspring.com,
Nick Piggin <nickpiggin@yahoo.com.au>,
linux-arch@vger.kernel.org, jesper.juhl@gmail.com,
satyam@infradead.org, zlynx@acm.org, schwidefsky@de.ibm.com,
Chris Snook <csnook@redhat.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
davem@davemloft.net,
Linus Torvalds <torvalds@linux-foundation.org>,
wensong@linux-vs.org, wjiang@resilience.com
Subject: Re: [PATCH 0/24] make atomic_read() behave consistently across all architectures
Date: Tue, 21 Aug 2007 19:33:49 +1000 [thread overview]
Message-ID: <18122.45437.807239.395869@cargo.ozlabs.ibm.com> (raw)
In-Reply-To: <20070821070555.GA32036@flint.arm.linux.org.uk>
Russell King writes:
> Let me say it more clearly: On ARM, it is impossible to perform atomic
> operations on MMIO space.
Actually, no one is suggesting that we try to do that at all.
The discussion about RMW ops on MMIO space started with a comment
attributed to the gcc developers that one reason why gcc on x86
doesn't use instructions that do RMW ops on volatile variables is that
volatile is used to mark MMIO addresses, and there was some
uncertainty about whether (non-atomic) RMW ops on x86 could be used on
MMIO. This is in regard to the question about why gcc on x86 always
moves a volatile variable into a register before doing anything to it.
So the whole discussion is irrelevant to ARM, PowerPC and any other
architecture except x86[-64].
Paul.
next prev parent reply other threads:[~2007-08-21 9:34 UTC|newest]
Thread overview: 311+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-09 13:14 [PATCH 0/24] make atomic_read() behave consistently across all architectures Chris Snook
2007-08-09 12:41 ` Arnd Bergmann
2007-08-09 14:29 ` Chris Snook
2007-08-09 15:30 ` Arnd Bergmann
2007-08-14 22:31 ` Christoph Lameter
2007-08-14 22:45 ` Chris Snook
2007-08-14 22:51 ` Christoph Lameter
2007-08-14 23:08 ` Satyam Sharma
2007-08-14 23:04 ` Chris Snook
2007-08-14 23:14 ` Christoph Lameter
2007-08-15 6:49 ` Herbert Xu
2007-08-15 8:18 ` Heiko Carstens
2007-08-15 13:53 ` Stefan Richter
2007-08-15 14:35 ` Satyam Sharma
2007-08-15 14:52 ` Herbert Xu
2007-08-15 16:09 ` Stefan Richter
2007-08-15 16:27 ` Paul E. McKenney
2007-08-15 17:13 ` Satyam Sharma
2007-08-15 18:31 ` Segher Boessenkool
2007-08-15 18:57 ` Paul E. McKenney
2007-08-15 19:54 ` Satyam Sharma
2007-08-15 20:17 ` Paul E. McKenney
2007-08-15 20:52 ` Segher Boessenkool
2007-08-15 22:42 ` Paul E. McKenney
2007-08-15 20:47 ` Segher Boessenkool
2007-08-16 0:36 ` Satyam Sharma
2007-08-16 0:32 ` your mail Herbert Xu
2007-08-16 0:58 ` [PATCH 0/24] make atomic_read() behave consistently across all architectures Satyam Sharma
2007-08-16 0:51 ` Herbert Xu
2007-08-16 1:18 ` Satyam Sharma
2007-08-16 1:38 ` Segher Boessenkool
2007-08-15 21:05 ` [PATCH 0/24] make atomic_read() behave consistently across all architectures Segher Boessenkool
2007-08-15 22:44 ` Paul E. McKenney
2007-08-16 1:23 ` Segher Boessenkool
2007-08-16 2:22 ` Paul E. McKenney
2007-08-15 19:58 ` Stefan Richter
2007-08-16 0:39 ` [PATCH] i386: Fix a couple busy loops in mach_wakecpu.h:wait_for_init_deassert() Satyam Sharma
2007-08-24 11:59 ` Denys Vlasenko
2007-08-24 12:07 ` Andi Kleen
2007-08-24 12:12 ` Kenn Humborg
2007-08-24 14:25 ` Denys Vlasenko
2007-08-24 17:34 ` Linus Torvalds
2007-08-24 13:30 ` Satyam Sharma
2007-08-24 17:06 ` Christoph Lameter
2007-08-24 20:26 ` Denys Vlasenko
2007-08-24 20:34 ` Chris Snook
2007-08-24 16:19 ` Luck, Tony
2007-08-15 16:13 ` [PATCH 0/24] make atomic_read() behave consistently across all architectures Chris Snook
2007-08-15 23:40 ` Herbert Xu
2007-08-15 23:51 ` Paul E. McKenney
2007-08-16 1:30 ` Segher Boessenkool
2007-08-16 2:30 ` Paul E. McKenney
2007-08-16 19:33 ` Segher Boessenkool
2007-08-16 1:26 ` Segher Boessenkool
2007-08-16 2:23 ` Nick Piggin
2007-08-16 19:32 ` Segher Boessenkool
2007-08-17 2:19 ` Nick Piggin
2007-08-17 3:16 ` Paul Mackerras
2007-08-17 3:32 ` Nick Piggin
2007-08-17 3:50 ` Linus Torvalds
2007-08-17 23:59 ` Paul E. McKenney
2007-08-18 0:09 ` Herbert Xu
2007-08-18 1:08 ` Paul E. McKenney
2007-08-18 1:24 ` Christoph Lameter
2007-08-18 1:41 ` Satyam Sharma
2007-08-18 4:13 ` Linus Torvalds
2007-08-18 13:36 ` Satyam Sharma
2007-08-18 21:54 ` Paul E. McKenney
2007-08-18 22:41 ` Linus Torvalds
2007-08-18 23:19 ` Paul E. McKenney
2007-08-24 12:19 ` Denys Vlasenko
2007-08-24 17:19 ` Linus Torvalds
2007-08-18 21:56 ` Paul E. McKenney
2007-08-20 13:31 ` Chris Snook
2007-08-20 22:04 ` Segher Boessenkool
2007-08-20 22:48 ` Russell King
2007-08-20 23:02 ` Segher Boessenkool
2007-08-21 0:05 ` Paul E. McKenney
2007-08-21 7:08 ` Russell King
2007-08-21 7:05 ` Russell King
2007-08-21 9:33 ` Paul Mackerras [this message]
2007-08-21 11:37 ` Andi Kleen
2007-08-21 14:48 ` Segher Boessenkool
2007-08-21 16:16 ` Paul E. McKenney
2007-08-21 22:51 ` Valdis.Kletnieks
2007-08-22 0:50 ` Paul E. McKenney
2007-08-22 21:38 ` Adrian Bunk
2007-08-21 14:39 ` Segher Boessenkool
2007-08-17 3:42 ` Linus Torvalds
2007-08-17 5:18 ` Paul E. McKenney
2007-08-17 5:56 ` Satyam Sharma
2007-08-17 7:26 ` Nick Piggin
2007-08-17 8:47 ` Satyam Sharma
2007-08-17 9:15 ` Nick Piggin
2007-08-17 10:12 ` Satyam Sharma
2007-08-17 12:14 ` Nick Piggin
2007-08-17 13:05 ` Satyam Sharma
2007-08-17 9:48 ` Paul Mackerras
2007-08-17 10:23 ` Satyam Sharma
2007-08-17 22:49 ` Segher Boessenkool
2007-08-17 23:51 ` Satyam Sharma
2007-08-17 23:55 ` Segher Boessenkool
2007-08-17 6:42 ` Geert Uytterhoeven
2007-08-17 8:52 ` Andi Kleen
2007-08-17 10:08 ` Satyam Sharma
2007-08-17 22:29 ` Segher Boessenkool
2007-08-17 17:37 ` Segher Boessenkool
2007-08-14 23:26 ` Paul E. McKenney
2007-08-15 10:35 ` Stefan Richter
2007-08-15 12:04 ` Herbert Xu
2007-08-15 12:31 ` Satyam Sharma
2007-08-15 13:08 ` Stefan Richter
2007-08-15 13:11 ` Stefan Richter
2007-08-15 13:47 ` Satyam Sharma
2007-08-15 14:25 ` Paul E. McKenney
2007-08-15 15:33 ` Herbert Xu
2007-08-15 16:08 ` Paul E. McKenney
2007-08-15 17:18 ` Satyam Sharma
2007-08-15 17:33 ` Paul E. McKenney
2007-08-15 18:05 ` Satyam Sharma
2007-08-15 17:55 ` Satyam Sharma
2007-08-15 19:07 ` Paul E. McKenney
2007-08-15 21:07 ` Segher Boessenkool
2007-08-15 20:58 ` Segher Boessenkool
2007-08-15 18:19 ` David Howells
2007-08-15 18:45 ` Paul E. McKenney
2007-08-15 23:41 ` Herbert Xu
2007-08-15 23:53 ` Paul E. McKenney
2007-08-16 0:12 ` Herbert Xu
2007-08-16 0:23 ` Paul E. McKenney
2007-08-16 0:30 ` Herbert Xu
2007-08-16 0:49 ` Paul E. McKenney
2007-08-16 0:53 ` Herbert Xu
2007-08-16 1:14 ` Paul E. McKenney
2007-08-15 18:31 ` Segher Boessenkool
2007-08-15 19:40 ` Satyam Sharma
2007-08-15 20:42 ` Segher Boessenkool
2007-08-16 1:23 ` Satyam Sharma
2007-08-15 23:22 ` Paul Mackerras
2007-08-16 0:26 ` Christoph Lameter
2007-08-16 0:34 ` Paul Mackerras
2007-08-16 0:40 ` Christoph Lameter
2007-08-16 0:39 ` Paul E. McKenney
2007-08-16 0:42 ` Christoph Lameter
2007-08-16 0:53 ` Paul E. McKenney
2007-08-16 0:59 ` Christoph Lameter
2007-08-16 1:14 ` Paul E. McKenney
2007-08-16 1:41 ` Christoph Lameter
2007-08-16 2:15 ` Satyam Sharma
2007-08-16 2:08 ` Herbert Xu
2007-08-16 2:18 ` Christoph Lameter
2007-08-16 3:23 ` Paul Mackerras
2007-08-16 3:33 ` Herbert Xu
2007-08-16 3:48 ` Paul Mackerras
2007-08-16 4:03 ` Herbert Xu
2007-08-16 4:34 ` Paul Mackerras
2007-08-16 5:37 ` Herbert Xu
2007-08-16 6:00 ` Paul Mackerras
2007-08-16 18:50 ` Christoph Lameter
2007-08-16 18:48 ` Christoph Lameter
2007-08-16 19:44 ` Segher Boessenkool
2007-08-16 2:18 ` Chris Friesen
2007-08-16 2:32 ` Paul E. McKenney
2007-08-16 1:51 ` Paul Mackerras
2007-08-16 2:00 ` Herbert Xu
2007-08-16 2:05 ` Paul Mackerras
2007-08-16 2:11 ` Herbert Xu
2007-08-16 2:35 ` Paul E. McKenney
2007-08-16 3:15 ` Paul Mackerras
2007-08-16 3:43 ` Herbert Xu
2007-08-16 2:15 ` Christoph Lameter
2007-08-16 2:17 ` Christoph Lameter
2007-08-16 2:33 ` Satyam Sharma
2007-08-16 3:01 ` Satyam Sharma
2007-08-16 4:11 ` Paul Mackerras
2007-08-16 5:39 ` Herbert Xu
2007-08-16 6:56 ` Paul Mackerras
2007-08-16 7:09 ` Herbert Xu
2007-08-16 8:06 ` Stefan Richter
2007-08-16 8:10 ` Herbert Xu
2007-08-16 9:54 ` Stefan Richter
2007-08-16 10:31 ` Stefan Richter
2007-08-16 10:42 ` Herbert Xu
2007-08-16 16:34 ` Paul E. McKenney
2007-08-16 23:59 ` Herbert Xu
2007-08-17 1:01 ` Paul E. McKenney
2007-08-17 7:39 ` Satyam Sharma
2007-08-17 14:31 ` Paul E. McKenney
2007-08-17 18:31 ` Satyam Sharma
2007-08-17 18:56 ` Paul E. McKenney
2007-08-17 3:15 ` Nick Piggin
2007-08-17 4:02 ` Paul Mackerras
2007-08-17 4:39 ` Nick Piggin
2007-08-17 7:25 ` Stefan Richter
2007-08-17 8:06 ` Nick Piggin
2007-08-17 8:58 ` Satyam Sharma
2007-08-17 9:15 ` Nick Piggin
2007-08-17 10:03 ` Satyam Sharma
2007-08-17 11:50 ` Nick Piggin
2007-08-17 12:50 ` Satyam Sharma
2007-08-17 12:56 ` Nick Piggin
2007-08-18 2:15 ` Satyam Sharma
2007-08-17 10:48 ` Stefan Richter
2007-08-17 10:58 ` Stefan Richter
2007-08-18 14:35 ` LDD3 pitfalls (was Re: [PATCH 0/24] make atomic_read() behave consistently across all architectures) Stefan Richter
2007-08-20 13:28 ` Chris Snook
2007-08-17 22:14 ` [PATCH 0/24] make atomic_read() behave consistently across all architectures Segher Boessenkool
2007-08-17 5:04 ` Paul Mackerras
2007-08-16 10:35 ` Herbert Xu
2007-08-16 19:48 ` Chris Snook
2007-08-17 0:02 ` Herbert Xu
2007-08-17 2:04 ` Chris Snook
2007-08-17 2:13 ` Herbert Xu
2007-08-17 2:31 ` Nick Piggin
2007-08-17 5:09 ` Paul Mackerras
2007-08-17 5:32 ` Herbert Xu
2007-08-17 5:41 ` Paul Mackerras
2007-08-17 8:28 ` Satyam Sharma
2007-08-16 14:48 ` Ilpo Järvinen
2007-08-16 16:19 ` Stefan Richter
2007-08-16 19:55 ` Chris Snook
2007-08-16 20:20 ` Christoph Lameter
2007-08-17 1:02 ` Paul E. McKenney
2007-08-17 1:28 ` Herbert Xu
2007-08-17 5:07 ` Paul E. McKenney
2007-08-17 2:16 ` Paul Mackerras
2007-08-17 3:03 ` Linus Torvalds
2007-08-17 3:43 ` Paul Mackerras
2007-08-17 3:53 ` Herbert Xu
2007-08-17 6:26 ` Satyam Sharma
2007-08-17 8:38 ` Nick Piggin
2007-08-17 9:14 ` Satyam Sharma
2007-08-17 9:31 ` Nick Piggin
2007-08-17 10:55 ` Satyam Sharma
2007-08-17 12:39 ` Nick Piggin
2007-08-17 13:36 ` Satyam Sharma
2007-08-17 16:48 ` Linus Torvalds
2007-08-17 18:50 ` Chris Friesen
2007-08-17 18:54 ` Arjan van de Ven
2007-08-17 19:49 ` Paul E. McKenney
2007-08-17 19:49 ` Arjan van de Ven
2007-08-17 20:12 ` Paul E. McKenney
2007-08-17 19:08 ` Linus Torvalds
2007-08-20 13:15 ` Chris Snook
2007-08-20 13:32 ` Herbert Xu
2007-08-20 13:38 ` Chris Snook
2007-08-20 22:07 ` Segher Boessenkool
2007-08-21 5:46 ` Linus Torvalds
2007-08-21 7:04 ` David Miller
2007-08-21 13:50 ` Chris Snook
2007-08-21 14:59 ` Segher Boessenkool
2007-08-21 16:31 ` Satyam Sharma
2007-08-21 16:43 ` Linus Torvalds
2007-09-09 18:02 ` Denys Vlasenko
2007-09-09 18:18 ` Arjan van de Ven
2007-09-10 10:56 ` Denys Vlasenko
2007-09-10 11:15 ` Herbert Xu
2007-09-10 12:22 ` Kyle Moffett
2007-09-10 13:38 ` Denys Vlasenko
2007-09-10 14:16 ` Denys Vlasenko
2007-09-10 15:09 ` Linus Torvalds
2007-09-10 16:46 ` Denys Vlasenko
2007-09-10 19:59 ` Kyle Moffett
2007-09-10 18:59 ` Christoph Lameter
2007-09-10 23:19 ` [PATCH] Document non-semantics of atomic_read() and atomic_set() Chris Snook
2007-09-10 23:44 ` Paul E. McKenney
2007-09-11 19:35 ` Christoph Lameter
2007-09-10 14:51 ` [PATCH 0/24] make atomic_read() behave consistently across all architectures Arjan van de Ven
2007-09-10 14:38 ` Denys Vlasenko
2007-09-10 17:02 ` Arjan van de Ven
2007-08-17 11:08 ` Stefan Richter
2007-08-17 22:09 ` Segher Boessenkool
2007-08-17 17:41 ` Segher Boessenkool
2007-08-17 18:38 ` Satyam Sharma
2007-08-17 23:17 ` Segher Boessenkool
2007-08-17 23:55 ` Satyam Sharma
2007-08-18 0:04 ` Segher Boessenkool
2007-08-18 1:56 ` Satyam Sharma
2007-08-18 2:15 ` Segher Boessenkool
2007-08-18 3:33 ` Satyam Sharma
2007-08-18 5:18 ` Segher Boessenkool
2007-08-18 13:20 ` Satyam Sharma
2007-09-10 18:59 ` Christoph Lameter
2007-09-10 20:54 ` Paul E. McKenney
2007-09-10 21:36 ` Christoph Lameter
2007-09-10 21:50 ` Paul E. McKenney
2007-09-11 2:27 ` Segher Boessenkool
2007-08-16 21:08 ` Luck, Tony
2007-08-16 19:55 ` Chris Snook
2007-08-16 18:54 ` Christoph Lameter
2007-08-16 20:07 ` Paul E. McKenney
2007-08-16 3:05 ` Paul Mackerras
2007-08-16 19:39 ` Segher Boessenkool
2007-08-16 2:07 ` Segher Boessenkool
2007-08-24 12:50 ` Denys Vlasenko
2007-08-24 17:15 ` Christoph Lameter
2007-08-24 20:21 ` Denys Vlasenko
2007-08-16 3:37 ` Bill Fink
2007-08-16 5:20 ` Satyam Sharma
2007-08-16 5:57 ` Satyam Sharma
2007-08-16 9:25 ` Satyam Sharma
2007-08-16 21:00 ` Segher Boessenkool
2007-08-17 4:32 ` Satyam Sharma
2007-08-17 22:38 ` Segher Boessenkool
2007-08-18 14:42 ` Satyam Sharma
2007-08-16 20:50 ` Segher Boessenkool
2007-08-16 22:40 ` David Schwartz
2007-08-17 4:36 ` Satyam Sharma
2007-08-17 4:24 ` Satyam Sharma
2007-08-17 22:34 ` Segher Boessenkool
2007-08-15 19:59 ` Christoph Lameter
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