From: Andrew Haley <aph@redhat.com>
To: rostedt@goodmis.org
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@zytor.com>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
feng.tang@intel.com,
Fr??d??ric Weisbecker <fweisbec@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
jakub@redhat.com, gcc@gcc.gnu.org
Subject: Re: BUG: GCC-4.4.x changes the function frame on some functions
Date: Thu, 19 Nov 2009 18:38:00 -0000 [thread overview]
Message-ID: <4B05903B.5080708@redhat.com> (raw)
In-Reply-To: <1258655585.22249.751.camel@gandalf.stny.rr.com>
Steven Rostedt wrote:
> On Thu, 2009-11-19 at 18:20 +0000, Andrew Haley wrote:
>
>> OK, I found it. There is a struct defined as
>>
>> struct entry {
>> ...
>> } __attribute__((__aligned__((1 << (4)))));
>>
>> and then in timer_stats_update_stats you have a local variable of type
>> struct entry:
>>
>> void timer_stats_update_stats()
>> {
>> spinlock_t *lock;
>> struct entry *entry, input;
>>
>> So, gcc has to 16-align the stack pointer to satisfy the alignment
>> for struct entry.
>
> It has to align the entire stack? Why not just the variable within the
> stack?
How?. gcc has to know, at compile time, the offset from sp of each variable.
So, it of course makes sure that offset is 16-aligned, but it also has to
16-align the stack pointer.
Andrew.
next prev parent reply other threads:[~2009-11-19 18:38 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <alpine.LFD.2.00.0911181933540.24119@localhost.localdomain>
[not found] ` <tip-887a29f59b93cf54e21814869a4ab6e80b6fa623@git.kernel.org>
[not found] ` <20091119072040.GA23579@elte.hu>
[not found] ` <alpine.LFD.2.00.0911191053390.24119@localhost.localdomain>
[not found] ` <alpine.LFD.2.00.0911191423190.24119@localhost.localdomain>
2009-11-19 15:39 ` Thomas Gleixner
2009-11-19 15:45 ` Andrew Haley
2009-11-19 15:55 ` H. Peter Anvin
2009-11-19 15:59 ` Richard Guenther
2009-11-19 16:03 ` Steven Rostedt
2009-11-19 16:13 ` H. Peter Anvin
2009-11-19 16:20 ` Frederic Weisbecker
2009-11-19 16:07 ` Thomas Gleixner
2009-11-19 16:19 ` Andrew Haley
2009-11-19 16:45 ` Thomas Gleixner
2009-11-19 16:13 ` Steven Rostedt
2009-11-19 15:46 ` H. Peter Anvin
2009-11-19 15:51 ` Richard Guenther
2009-11-19 15:53 ` Richard Guenther
2009-11-19 17:38 ` Andi Kleen
2009-11-19 17:41 ` Linus Torvalds
2009-11-19 17:52 ` Thomas Gleixner
2009-11-19 18:00 ` Steven Rostedt
2009-11-19 18:04 ` Richard Guenther
2009-11-19 18:23 ` Andrew Haley
2009-11-19 18:42 ` Linus Torvalds
2009-11-19 18:45 ` Linus Torvalds
2009-11-19 18:56 ` Linus Torvalds
2009-11-19 19:03 ` Thomas Gleixner
2009-11-23 9:17 ` Jakub Jelinek
2009-11-23 9:53 ` Thomas Gleixner
2009-11-19 19:12 ` David Daney
2009-11-19 19:29 ` Steven Rostedt
2009-11-19 19:47 ` Frederic Weisbecker
2009-11-19 19:55 ` Kai Tietz
2009-11-19 20:06 ` Frederic Weisbecker
2009-11-19 20:06 ` Steven Rostedt
2009-11-19 20:18 ` Steven Rostedt
2009-11-19 20:29 ` Frederic Weisbecker
2009-11-19 20:26 ` Frederic Weisbecker
2009-11-19 20:38 ` Linus Torvalds
2009-11-19 20:45 ` Steven Rostedt
2009-11-19 19:51 ` H. Peter Anvin
2009-11-19 20:08 ` Linus Torvalds
2009-11-19 21:13 ` Jeff Law
2009-11-19 20:11 ` Steven Rostedt
2009-11-19 21:07 ` Jeff Law
2009-11-19 18:34 ` Thomas Gleixner
2009-11-19 18:40 ` Linus Torvalds
2009-11-19 18:48 ` Ingo Molnar
2009-11-19 19:08 ` Steven Rostedt
2009-11-19 19:51 ` Ingo Molnar
2009-11-20 9:58 ` [PATCH] gcc mcount-nofp was " Andi Kleen
2009-11-20 12:35 ` Steven Rostedt
2009-11-20 19:08 ` H. Peter Anvin
2009-11-19 20:37 ` Thomas Gleixner
2009-11-19 18:22 ` Andrew Haley
2009-11-19 18:34 ` Steven Rostedt
2009-11-19 18:37 ` Andrew Pinski
2009-11-19 18:38 ` H. Peter Anvin
2009-11-19 18:38 ` Andrew Haley [this message]
2009-11-19 18:40 ` Thomas Gleixner
2009-11-20 5:24 ` [PATCH][GIT PULL][v2.6.32] tracing/x86: Add check to detect GCC messing with mcount prologue Steven Rostedt
2009-11-20 5:33 ` Steven Rostedt
2009-11-20 17:02 ` Steven Rostedt
2009-11-20 17:15 ` H. Peter Anvin
2009-11-20 19:36 ` Andrew Haley
2009-11-20 19:48 ` Steven Rostedt
2009-11-20 19:50 ` H. Peter Anvin
2009-11-22 9:39 ` H.J. Lu
2009-11-22 17:21 ` Andrew Haley
2009-11-22 23:31 ` H.J. Lu
2009-11-24 14:43 ` Andrew Haley
2009-11-24 14:56 ` Thomas Gleixner
2009-11-24 15:06 ` Jakub Jelinek
2009-11-24 15:32 ` Andrew Haley
2009-11-24 15:36 ` Jakub Jelinek
2009-11-24 15:48 ` Andrew Haley
2009-11-24 16:39 ` H. Peter Anvin
2009-11-24 17:12 ` Andrew Haley
2009-11-24 17:30 ` Steven Rostedt
2009-11-25 20:05 ` H. Peter Anvin
2009-11-24 19:56 ` H. Peter Anvin
2009-11-25 15:29 ` Thomas Gleixner
2009-11-25 15:45 ` Ingo Molnar
2009-11-25 15:53 ` Thomas Gleixner
2009-11-25 16:26 ` Ingo Molnar
2009-11-25 16:45 ` Jakub Jelinek
2009-11-25 20:13 ` H. Peter Anvin
2009-11-25 21:01 ` Andrew Haley
2009-11-22 9:06 ` Ingo Molnar
2009-11-19 20:50 BUG: GCC-4.4.x changes the function frame on some functions H. Peter Anvin
2009-11-19 21:16 H. Peter Anvin
2009-11-19 21:26 ` Jeff Law
2009-11-19 22:44 ` Steven Rostedt
2009-11-20 0:00 ` Jeff Law
2009-11-20 0:37 ` Thomas Gleixner
2009-11-20 1:00 ` Linus Torvalds
2009-11-20 1:29 ` Thomas Gleixner
2009-11-20 2:16 ` Thomas Gleixner
2009-11-20 1:30 ` H. Peter Anvin
2009-11-20 5:40 ` Ingo Molnar
2009-11-20 12:06 ` Andrew Haley
2009-11-20 12:23 ` Andrew Haley
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