From: Andreas Schwab <schwab@linux-m68k.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: Jim <jim876@xs4all.nl>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
gcc@gcc.gnu.org
Subject: Re: gcc 4.5.1 / as 2.20.51.0.11 miscompiling drivers/char/i8k.c ?
Date: Sun, 07 Nov 2010 23:41:37 +0100 [thread overview]
Message-ID: <m2hbfsu57i.fsf@igel.home> (raw)
In-Reply-To: <87wroostw3.fsf@basil.nowhere.org> (Andi Kleen's message of "Sun, 07 Nov 2010 22:31:24 +0100")
Andi Kleen <andi@firstfloor.org> writes:
> Jim <jim876@xs4all.nl> writes:
>
>> After upgrading my Dell laptop, both OS+kernel the i8k interface was giving
>> nonsensical output. As it turned out it's not the kernel but compiler
>> upgrade which broke this.
>>
>> Guys at Archlinux have found the underlying cause (but don't seem to have
>> submitted a patch yet):
>> https://bbs.archlinux.org/viewtopic.php?pid=780692#p780692
>> gcc seems to optimize the assembly statements away.
>>
>> And indeed, applying this patch makes the i8k interface work again,
>> i.e. replacing the asm(..) construct by asm volatile(..)
>
> The compiler really should not optimize the asm away, because
> it has both input and output arguments which are later used.
> "asm volatile" normally just means "don't move significantly"
The asm fails to mention that it modifies *regs.
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
next prev parent reply other threads:[~2010-11-07 22:41 UTC|newest]
Thread overview: 129+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-06 11:15 gcc 4.5.1 / as 2.20.51.0.11 miscompiling drivers/char/i8k.c ? Jim
2010-11-07 21:31 ` Andi Kleen
2010-11-07 22:41 ` Andreas Schwab [this message]
2010-11-07 23:03 ` Andi Kleen
2010-11-08 10:49 ` Richard Guenther
2010-11-08 11:20 ` Andi Kleen
2010-11-08 11:20 ` Richard Guenther
2010-11-08 11:47 ` Paul Koning
2010-11-08 11:53 ` Jakub Jelinek
2010-11-08 12:20 ` Michael Matz
2010-11-08 18:39 ` Dave Korn
2010-11-09 13:00 ` Michael Matz
2010-11-09 13:48 ` Andi Kleen
2010-11-09 13:57 ` Andreas Schwab
2010-11-09 16:43 ` Jim
2010-11-13 11:13 ` [PATCH] i8k: Tell gcc that *regs gets clobbered Jim Bos
2010-11-15 0:52 ` gcc 4.5.1 / as 2.20.51.0.11 miscompiling drivers/char/i8k.c ? James Cloos
2010-11-15 3:21 ` Linus Torvalds
2010-11-15 8:56 ` Jakub Jelinek
2010-11-15 9:12 ` Andi Kleen
2010-11-15 9:20 ` Jakub Jelinek
2010-11-15 10:03 ` Jakub Jelinek
2010-11-15 10:54 ` Andi Kleen
2010-11-15 11:16 ` Jakub Jelinek
2010-11-15 11:37 ` Andi Kleen
2010-11-15 17:36 ` Jim Bos
2010-11-15 17:44 ` Jakub Jelinek
2010-11-15 18:17 ` Jim Bos
2010-11-15 18:26 ` Jakub Jelinek
2010-11-15 19:10 ` Jim Bos
2010-11-15 16:04 ` Linus Torvalds
2010-11-15 17:40 ` Jim Bos
2010-11-15 18:08 ` Linus Torvalds
2010-11-15 18:30 ` Jim Bos
2010-11-15 18:37 ` Jim Bos
2010-11-15 18:56 ` Linus Torvalds
2010-11-15 18:58 ` Jakub Jelinek
2010-11-15 19:12 ` Jakub Jelinek
2010-11-15 19:21 ` Linus Torvalds
2010-11-15 19:51 ` Jakub Jelinek
2010-11-15 20:22 ` Jim Bos
2011-06-03 13:05 ` 2.6.39.1 immediately reboots/resets on EFI system Jim Bos
2011-06-03 13:33 ` Matthew Garrett
2011-06-03 14:26 ` Jim Bos
2011-06-03 14:46 ` Matthew Garrett
2011-06-05 10:40 ` Jim Bos
2011-06-05 12:57 ` Maarten Lankhorst
2011-06-06 15:01 ` Maarten Lankhorst
2011-06-06 15:40 ` Jim Bos
2011-06-06 15:44 ` Matthew Garrett
2011-06-06 15:27 ` Maarten Lankhorst
2011-06-06 16:11 ` Jim Bos
2011-06-06 16:43 ` Maarten Lankhorst
2011-06-07 0:19 ` Yinghai Lu
2011-06-07 1:41 ` Matthew Garrett
2011-06-07 2:05 ` Yinghai Lu
2011-06-07 8:25 ` Maarten Lankhorst
2011-06-07 15:14 ` Yinghai Lu
2011-06-07 9:08 ` Maarten Lankhorst
2011-06-07 12:22 ` Maarten Lankhorst
2011-06-07 22:25 ` Yinghai Lu
2011-06-08 16:44 ` Jim Bos
2011-06-08 19:17 ` Yinghai Lu
2011-06-08 19:23 ` Matthew Garrett
2011-06-08 19:27 ` Yinghai Lu
2011-06-08 19:29 ` Matthew Garrett
2011-06-08 19:35 ` Yinghai Lu
2011-06-08 19:38 ` Matthew Garrett
2011-06-08 19:46 ` Yinghai Lu
2011-06-08 19:52 ` Matthew Garrett
2011-06-08 19:48 ` Yinghai Lu
2011-06-08 19:52 ` Matthew Garrett
2011-06-08 20:03 ` Yinghai Lu
2011-06-08 20:09 ` Matthew Garrett
2011-06-08 20:23 ` Yinghai Lu
2011-06-08 20:30 ` Matthew Garrett
2011-06-08 20:36 ` Yinghai Lu
2011-06-08 20:42 ` Matthew Garrett
2011-06-08 20:46 ` Yinghai Lu
2011-06-08 21:06 ` Matthew Garrett
2011-06-08 21:06 ` Linus Torvalds
2011-06-08 21:28 ` Matthew Garrett
2011-06-08 21:31 ` H. Peter Anvin
2011-06-08 21:36 ` Matthew Garrett
2011-06-08 21:31 ` Linus Torvalds
2011-06-08 21:42 ` Matthew Garrett
2011-06-08 21:51 ` H. Peter Anvin
2011-06-08 22:57 ` Linus Torvalds
2011-06-08 23:54 ` Maarten Lankhorst
2011-06-08 21:38 ` Yinghai Lu
2011-06-10 16:47 ` Matthew Garrett
2011-06-10 17:51 ` Maarten Lankhorst
2011-06-10 17:54 ` Matthew Garrett
2011-06-10 22:45 ` Maarten Lankhorst
2011-06-10 22:58 ` Yinghai Lu
2011-06-10 23:03 ` Matthew Garrett
2011-06-10 23:17 ` Greg KH
2011-06-10 23:22 ` Maarten Lankhorst
2011-06-10 23:25 ` H. Peter Anvin
2011-06-10 23:26 ` Yinghai Lu
2011-06-10 23:32 ` H. Peter Anvin
2011-06-10 23:55 ` Yinghai Lu
2011-06-11 0:00 ` H. Peter Anvin
2011-06-11 0:19 ` Yinghai Lu
2011-06-14 18:06 ` H. Peter Anvin
2011-06-11 15:29 ` Matthew Garrett
2011-06-10 23:00 ` Yinghai Lu
2011-06-13 16:47 ` Matthew Garrett
2011-06-13 17:52 ` Maarten Lankhorst
2011-06-13 18:00 ` Matthew Garrett
2011-06-13 18:14 ` Maarten Lankhorst
2011-06-13 18:17 ` Matthew Garrett
2011-06-13 18:23 ` Maarten Lankhorst
2011-06-13 18:33 ` Matthew Garrett
2011-06-13 18:45 ` Maarten Lankhorst
2011-06-14 14:34 ` Maarten Lankhorst
2011-06-14 14:50 ` Maarten Lankhorst
2011-06-14 14:55 ` Matthew Garrett
2010-11-15 22:43 ` gcc 4.5.1 / as 2.20.51.0.11 miscompiling drivers/char/i8k.c ? Andi Kleen
2010-11-15 22:46 ` Jakub Jelinek
2010-11-15 19:53 ` Richard Henderson
2010-11-15 10:24 ` Richard Guenther
2010-11-15 18:45 ` Jeff Law
2010-11-15 19:04 ` Linus Torvalds
2010-11-15 22:07 ` Richard Guenther
2010-11-15 22:58 ` Jeff Law
2010-11-15 23:07 ` Richard Guenther
2010-11-16 4:10 ` Jeff Law
2010-11-15 18:42 ` Jeff Law
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