From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: David Miller <davem@davemloft.net>
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
linuxppc-dev@ozlabs.org, scottwood@freescale.com,
torvalds@linux-foundation.org, tpiepho@freescale.com,
alan@lxorguk.ukuu.org.uk
Subject: Re: MMIO and gcc re-ordering issue
Date: Tue, 27 May 2008 13:39:02 +1000 [thread overview]
Message-ID: <1211859542.3286.46.camel@pasglop> (raw)
In-Reply-To: <20080526.192812.184590464.davem@davemloft.net>
On Mon, 2008-05-26 at 19:28 -0700, David Miller wrote:
> > But heh, it's you who was telling me that it would be a bad
> engineering
> > decision and we had to make everybody look like x86 & fully
> ordered :-)
> > I decided to agree back then and stuck all those nasty heavy
> barriers
> > in the powerpc variants of readl/writel/...
>
> I still believe this.
>
> It's just another complicated thing for driver authors to get wrong.
> The other side of the coin is of course the cost.
>
> The only thing I am absolutely sure of is that we should make a
> decision fast, document it, and just stick to it.
Yes. As it is today, tg3 for example is potentially broken on all archs
with newer gcc unless we either add "memory" clobber to readl/writel or
stick some wmb's in there (just a random driver I picked).
So Linus, what is your take on that matter ?
Cheers,
Ben.
next prev parent reply other threads:[~2008-05-27 3:39 UTC|newest]
Thread overview: 160+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-20 20:40 [PATCH] [POWERPC] Improve (in|out)_beXX() asm code Trent Piepho
2008-05-20 21:16 ` Benjamin Herrenschmidt
2008-05-20 21:38 ` Scott Wood
2008-05-20 22:02 ` Benjamin Herrenschmidt
2008-05-20 22:21 ` Trent Piepho
2008-05-20 22:15 ` Alan Cox
2008-05-20 22:35 ` Scott Wood
2008-05-20 22:39 ` David Miller
2008-05-20 22:43 ` Scott Wood
2008-05-20 22:53 ` David Miller
2008-05-23 4:24 ` Benjamin Herrenschmidt
2008-05-22 22:56 ` Trent Piepho
2008-05-23 12:36 ` MMIO and gcc re-ordering (Was: [PATCH] [POWERPC] Improve (in|out)_beXX() asm code) Benjamin Herrenschmidt
2008-05-23 12:50 ` Benjamin Herrenschmidt
2008-05-23 21:14 ` Scott Wood
2008-05-23 22:47 ` Benjamin Herrenschmidt
2008-05-27 1:33 ` MMIO and gcc re-ordering issue Benjamin Herrenschmidt
2008-05-27 1:40 ` David Miller
2008-05-27 2:15 ` Benjamin Herrenschmidt
2008-05-27 2:28 ` David Miller
2008-05-27 3:39 ` Benjamin Herrenschmidt [this message]
2008-05-27 15:35 ` Linus Torvalds
2008-05-27 16:47 ` Linus Torvalds
2008-05-27 17:31 ` Linus Torvalds
2008-06-02 10:36 ` Ingo Molnar
2008-06-02 21:53 ` Benjamin Herrenschmidt
2008-05-27 21:12 ` Benjamin Herrenschmidt
2008-05-27 18:23 ` Trent Piepho
2008-05-27 18:33 ` Scott Wood
2008-05-27 21:10 ` Benjamin Herrenschmidt
2008-05-27 21:30 ` Linus Torvalds
2008-05-27 21:38 ` Alan Cox
2008-05-27 21:53 ` Matthew Wilcox
2008-05-27 21:46 ` Alan Cox
2008-05-27 22:02 ` Linus Torvalds
2008-05-27 21:59 ` Linus Torvalds
2008-05-27 21:38 ` Benjamin Herrenschmidt
2008-05-27 21:42 ` Matthew Wilcox
2008-05-27 22:17 ` Benjamin Herrenschmidt
2008-05-28 8:36 ` Haavard Skinnemoen
2008-05-29 11:05 ` Pantelis Antoniou
2008-05-30 1:13 ` Benjamin Herrenschmidt
2008-05-30 6:07 ` Haavard Skinnemoen
2008-05-30 7:24 ` Benjamin Herrenschmidt
2008-05-30 8:27 ` Haavard Skinnemoen
2008-05-30 9:22 ` Geert Uytterhoeven
2008-06-02 8:11 ` Haavard Skinnemoen
2008-06-02 15:48 ` Scott Wood
2008-06-03 7:46 ` Haavard Skinnemoen
2008-06-04 15:31 ` Linus Torvalds
2008-05-27 21:55 ` Linus Torvalds
2008-05-27 22:19 ` Benjamin Herrenschmidt
2008-05-29 7:10 ` Arnd Bergmann
2008-05-29 10:46 ` Alan Cox
2008-06-02 7:24 ` Russell King
2008-06-03 4:16 ` Nick Piggin
2008-06-03 4:32 ` Benjamin Herrenschmidt
2008-06-03 6:11 ` Nick Piggin
2008-06-03 6:48 ` Benjamin Herrenschmidt
2008-06-03 6:53 ` Paul Mackerras
2008-06-03 7:18 ` Nick Piggin
2008-06-03 14:47 ` Linus Torvalds
2008-06-03 18:47 ` Trent Piepho
2008-06-03 18:55 ` Matthew Wilcox
2008-06-03 19:57 ` Trent Piepho
2008-06-03 21:35 ` Matthew Wilcox
2008-06-03 21:58 ` Trent Piepho
2008-06-04 2:00 ` Nick Piggin
2008-06-03 19:07 ` Linus Torvalds
2008-06-04 2:05 ` Nick Piggin
2008-06-04 2:46 ` Linus Torvalds
2008-06-04 11:47 ` Alan Cox
2008-06-10 6:56 ` Nick Piggin
2008-06-10 17:41 ` Jesse Barnes
2008-06-10 18:10 ` James Bottomley
2008-06-10 19:05 ` Roland Dreier
2008-06-10 19:19 ` Jesse Barnes
2008-06-11 3:29 ` Nick Piggin
2008-06-11 3:40 ` Benjamin Herrenschmidt
2008-06-11 4:06 ` Nick Piggin
2008-06-11 16:07 ` Jesse Barnes
2008-06-12 11:27 ` Nick Piggin
2008-06-11 4:18 ` Paul Mackerras
2008-06-11 5:00 ` Nick Piggin
2008-06-11 5:13 ` Paul Mackerras
2008-06-11 5:35 ` Nick Piggin
2008-06-11 6:02 ` Nick Piggin
2008-06-12 12:14 ` Paul Mackerras
2008-06-12 13:08 ` Nick Piggin
2008-06-11 14:46 ` Linus Torvalds
2008-06-11 5:20 ` Paul Mackerras
2008-06-04 2:19 ` Nick Piggin
2008-06-03 19:43 ` Trent Piepho
2008-06-03 21:33 ` Matthew Wilcox
2008-06-03 21:44 ` Trent Piepho
2008-06-04 2:25 ` Nick Piggin
2008-06-04 6:39 ` Trent Piepho
2008-06-03 22:26 ` Benjamin Herrenschmidt
2008-05-27 3:42 ` Arjan van de Ven
2008-05-27 4:08 ` Roland Dreier
2008-05-27 4:20 ` Arjan van de Ven
2008-05-27 7:08 ` Benjamin Herrenschmidt
2008-05-27 15:50 ` Roland Dreier
2008-05-27 16:37 ` James Bottomley
2008-05-27 17:38 ` Roland Dreier
2008-05-27 17:53 ` James Bottomley
2008-05-27 18:07 ` Roland Dreier
2008-05-27 18:17 ` Roland Dreier
2008-05-27 21:23 ` Chris Friesen
2008-05-27 21:29 ` Roland Dreier
2008-05-27 23:04 ` Paul Mackerras
2008-05-27 21:11 ` Benjamin Herrenschmidt
2008-05-27 21:33 ` Roland Dreier
2008-05-27 22:13 ` Benjamin Herrenschmidt
2008-05-27 22:39 ` Roland Dreier
2008-05-29 14:47 ` Jes Sorensen
2008-05-29 15:01 ` James Bottomley
2008-05-30 9:36 ` Jes Sorensen
2008-05-30 17:21 ` Jesse Barnes
2008-05-31 7:57 ` Jeremy Higdon
2008-05-29 21:40 ` Benjamin Herrenschmidt
2008-05-29 21:48 ` Trent Piepho
2008-05-29 22:05 ` Benjamin Herrenschmidt
2008-05-30 1:53 ` Trent Piepho
2008-05-29 21:53 ` Jesse Barnes
2008-05-30 9:39 ` Jes Sorensen
2008-05-30 9:48 ` Jes Sorensen
2008-05-31 8:14 ` Pavel Machek
2008-06-02 9:48 ` Jes Sorensen
2008-05-29 22:06 ` Roland Dreier
2008-05-29 22:25 ` Trent Piepho
2008-05-30 3:56 ` Paul Mackerras
2008-05-31 7:52 ` Jeremy Higdon
2008-06-02 9:56 ` Jes Sorensen
2008-06-02 21:02 ` Jeremy Higdon
2008-06-03 4:33 ` Nick Piggin
2008-06-03 8:15 ` Jeremy Higdon
2008-06-03 8:19 ` Nick Piggin
2008-06-03 8:45 ` Jeremy Higdon
2008-06-03 16:52 ` Jesse Barnes
2008-06-05 8:40 ` Jes Sorensen
2008-06-05 8:43 ` Benjamin Herrenschmidt
2008-06-12 15:07 ` Matthew Wilcox
2008-06-13 0:07 ` Benjamin Herrenschmidt
2008-05-31 8:04 ` Pavel Machek
2008-05-27 8:24 ` Alan Cox
2008-05-27 15:28 ` Jonathan Corbet
2008-05-20 22:55 ` [PATCH] [POWERPC] Improve (in|out)_beXX() asm code Trent Piepho
2008-05-21 14:01 ` Benjamin Herrenschmidt
2008-05-20 22:00 ` Trent Piepho
2008-05-21 14:00 ` Benjamin Herrenschmidt
2008-05-21 19:44 ` Trent Piepho
2008-05-21 20:41 ` Benjamin Herrenschmidt
2008-05-20 22:00 ` Andreas Schwab
2008-05-20 22:11 ` Trent Piepho
2008-05-20 22:47 ` Andreas Schwab
2008-05-20 23:14 ` Trent Piepho
2008-05-21 8:03 ` Andreas Schwab
2008-05-21 20:25 ` Trent Piepho
2008-05-27 23:48 ` [PATCH V2] [POWERPC] Improve (in|out)_[bl]eXX() " Trent Piepho
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1211859542.3286.46.camel@pasglop \
--to=benh@kernel.crashing.org \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=davem@davemloft.net \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@ozlabs.org \
--cc=scottwood@freescale.com \
--cc=torvalds@linux-foundation.org \
--cc=tpiepho@freescale.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).