From: "H. Peter Anvin" <hpa@zytor.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@elte.hu>, Petr Tesarik <ptesarik@suse.cz>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86: remove unneeded endless loop in BUG()
Date: Thu, 19 Feb 2009 12:48:38 -0800 [thread overview]
Message-ID: <499DC5A6.1080305@zytor.com> (raw)
In-Reply-To: <499DC545.2030402@goop.org>
Jeremy Fitzhardinge wrote:
>
> There's no reason to expect an "asm volatile" to stay put; the
> "volatile" has nothing to do with preventing code motion. The only way
> to make an asm stick in one place is with data dependencies, and I'm not
> sure what the dependency for __builtin_trap might be. I'm guessing its
> a "memory" clobber, but that's pure guesswork.
>
I looked through this with HJL; the bottom line is that although it
probably would work, it's not worth it.
I submitted GCC bug 39252 to get __builtin_not_reached(); instead.
-hpa
next prev parent reply other threads:[~2009-02-19 20:52 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-19 18:38 [PATCH] x86: remove unneeded endless loop in BUG() Petr Tesarik
2009-02-19 18:40 ` H. Peter Anvin
2009-02-19 18:59 ` Ingo Molnar
2009-02-19 19:53 ` H. Peter Anvin
2009-02-19 20:47 ` Jeremy Fitzhardinge
2009-02-19 20:48 ` H. Peter Anvin [this message]
2009-02-20 8:28 ` Petr Tesarik
2009-02-19 20:29 ` H. Peter Anvin
2009-02-19 20:32 ` Ingo Molnar
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