Message-ID: <4B06EF6F.2050507@redhat.com>
Date: Fri, 20 Nov 2009 19:35:11 +0000
From: Andrew Haley <aph@redhat.com>
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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,
       Peter Zijlstra <peterz@infradead.org>,
       Frederic Weisbecker <fweisbec@gmail.com>,
       David Daney <ddaney@caviumnetworks.com>,
       Richard Guenther <richard.guenther@gmail.com>, jakub@redhat.com,
       gcc <gcc@gcc.gnu.org>, Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH][GIT PULL][v2.6.32] tracing/x86: Add check to detect 
 GCC messing with mcount prologue
References: <alpine.LFD.2.00.0911181933540.24119@localhost.localdomain> 	 <tip-887a29f59b93cf54e21814869a4ab6e80b6fa623@git.kernel.org> 	 <20091119072040.GA23579@elte.hu> 	 <alpine.LFD.2.00.0911191053390.24119@localhost.localdomain> 	 <alpine.LFD.2.00.0911191423190.24119@localhost.localdomain> 	 <1258694593.22249.1012.camel@gandalf.stny.rr.com> <1258736456.22249.1032.camel@gandalf.stny.rr.com>
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Steven Rostedt wrote:
> Ingo, Thomas and Linus,
> 
> I know Thomas did a patch to force the -mtune=generic, but just in case
> gcc decides to do something crazy again, this patch will catch it.
> 
> Should we try to get this in now?

I'm sure this makes sense, but a gcc test case would be even better.
If this can be detected in the gcc test suite it'll be found and
fixed long before y'all in kernel land get to see it.  That's the
only way to guarantee this never bothers you again.

H.J., who wrote the code in question, is hopefully looking at why
this odd code is being generated.  Once he's done I can put a
suitable test case in the gcc test suite.

Andrew.
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