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From: "H. Peter Anvin" <hpa@zytor.com>
To: Keith Owens <kaos@ocs.com.au>
Cc: Trent Piepho <xyzzy@speakeasy.org>,
	Al Viro <viro@ftp.linux.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH][RFC] getting rid of stupid loop in BUG()
Date: Tue, 24 Jul 2007 22:09:24 -0700	[thread overview]
Message-ID: <46A6DB04.3000003@zytor.com> (raw)
In-Reply-To: <21803.1185331847@ocs10w.ocs.com.au>

Keith Owens wrote:
> Trent Piepho (on Tue, 24 Jul 2007 19:31:36 -0700 (PDT)) wrote:
>> Adding __builtin_trap after the
>> asm might be an ok fix.  It will emit a spurious int 6, but that won't even be
>> reached since the asm doesn't return, and it probably be less extra code than
>> the loop.
> 
> int 6 is a two byte instruction, the loop generates jmp with an 8 bit
> offset, also two bytes.  No change in code size.
> 

INT 6 is #UD, so the __builtin_trap() replaces the ud2a as well as the loop.

How far back was __builtin_trap() supported?

	-hpa

  reply	other threads:[~2007-07-25  5:14 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-24 15:39 [PATCH][RFC] getting rid of stupid loop in BUG() Al Viro
2007-07-24 16:56 ` Jeremy Fitzhardinge
2007-07-24 17:03   ` H. Peter Anvin
2007-07-24 17:14   ` Al Viro
2007-07-24 17:28     ` H. Peter Anvin
2007-07-24 18:58       ` Jeremy Fitzhardinge
2007-07-24 19:01         ` H. Peter Anvin
2007-07-24 19:13     ` Jeremy Fitzhardinge
2007-07-24 20:04       ` Al Viro
2007-07-24 21:14         ` Jeremy Fitzhardinge
2007-07-25  2:31 ` Trent Piepho
2007-07-25  2:50   ` Keith Owens
2007-07-25  5:09     ` H. Peter Anvin [this message]
2007-07-25  6:24       ` Jeremy Fitzhardinge
2007-07-25  6:29         ` David Miller
2007-07-25  6:50           ` Heiko Carstens
2007-07-25 16:56           ` Linus Torvalds
2007-07-25 17:00             ` Jeremy Fitzhardinge
2007-07-25 17:03               ` H. Peter Anvin
2007-07-25 17:19               ` Linus Torvalds
2007-07-25 17:25                 ` Al Viro
2007-07-25 17:36                   ` Jeremy Fitzhardinge
2007-07-25 19:35                     ` David Miller
2007-07-25 20:26                       ` H. Peter Anvin
2007-07-25 19:28               ` David Miller
2007-07-25 17:19             ` Al Viro
2007-07-25 17:22               ` H. Peter Anvin
2007-07-25 17:26                 ` Al Viro
2007-07-25 17:35                 ` David Howells
2007-07-25 17:41               ` Jeremy Fitzhardinge
2007-07-25 20:29                 ` Chuck Ebbert
2007-07-25 20:37                   ` H. Peter Anvin
2007-07-25 22:01                     ` David Miller
2007-07-25 18:24               ` Linus Torvalds
2007-07-25 17:36             ` Al Viro
2007-07-25 17:44               ` Jeremy Fitzhardinge

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