From: "H. Peter Anvin" <hpa@zytor.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
akpm@osdl.org, Rusty Russell <rusty@rustcorp.com.au>,
Glauber de Oliveira Costa <gcosta@redhat.com>,
Jan Beulich <jbeulich@novell.com>, Andi Kleen <ak@suse.de>,
Thomas Gleixner <tglx@linutronix.de>,
pinskia@gcc.gnu.org
Subject: Re: [PATCH] pop previous section in alternative.c
Date: Wed, 09 Apr 2008 17:20:18 -0700 [thread overview]
Message-ID: <47FD5D42.5000603@zytor.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0804091906040.31970@gandalf.stny.rr.com>
Steven Rostedt wrote:
> On Wed, 9 Apr 2008, Steven Rostedt wrote:
>
>> gcc expects all toplevel assembly to return to the original section type.
>> The code in alteranative.c does not do this. This caused some strange bugs
>> in sched-devel where code would end up in the .rodata section and when
>> the kernel sets the NX bit on all .rodata, the kernel would crash when
>> executing this code.
>>
>> This patch adds a .previous marker to return the code back to the
>> original section.
>>
>
> Oh, and this would not be complete without giving Andrew Pinski complete
> credit for telling me it wasn't a gcc bug but a bug in the toplevel asm
> code in the kernel. ;-)
>
In many ways it's kind of silly for this even to be in assembly, since
all it is is a sequence of comma-separated byte values; I guess it was
the easiest way to deal with it given the ".byte" prefix, but still...
-hpa
next prev parent reply other threads:[~2008-04-10 0:26 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-09 23:04 [PATCH] pop previous section in alternative.c Steven Rostedt
2008-04-09 23:51 ` Steven Rostedt
2008-04-10 0:20 ` H. Peter Anvin [this message]
2008-04-10 8:47 ` Andi Kleen
2008-04-10 9:46 ` Andy Whitcroft
2008-04-10 14:11 ` Steven Rostedt
2008-04-10 14:41 ` Andi Kleen
2008-04-10 14:43 ` Steven Rostedt
2008-04-10 14:46 ` Linus Torvalds
2008-04-10 14:55 ` Steven Rostedt
2008-04-10 18:40 ` Sam Ravnborg
2008-04-10 15:05 ` Andi Kleen
2008-04-10 15:18 ` Linus Torvalds
2008-04-10 16:07 ` H. Peter Anvin
2008-04-10 16:20 ` Steven Rostedt
2008-04-10 17:07 ` H. Peter Anvin
2008-04-10 17:32 ` Andrew Pinski
2008-04-10 17:53 ` H. Peter Anvin
2008-04-10 17:36 ` Linus Torvalds
2008-04-10 17:52 ` H. Peter Anvin
2008-04-13 15:27 ` Maciej W. Rozycki
2008-04-10 16:10 ` H. Peter Anvin
2008-04-10 7:00 ` Ingo Molnar
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