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From: "H. Peter Anvin" <hpa@zytor.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	David Miller <davem@davemloft.net>,
	Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
	Roland McGrath <roland@redhat.com>,
	Ulrich Drepper <drepper@redhat.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Gregory Haskins <ghaskins@novell.com>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	"Luis Claudio R. Goncalves" <lclaudio@uudg.org>,
	Clark Williams <williams@redhat.com>,
	srostedt@redhat.com
Subject: Re: [PATCH] ftrace: use only 5 byte nops for x86
Date: Fri, 15 Aug 2008 15:30:19 -0700	[thread overview]
Message-ID: <48A6037B.6030202@zytor.com> (raw)
In-Reply-To: <20080815092231.GB22209@elte.hu>

Ingo Molnar wrote:
>>>
>>> TODO: Examine the cpuid to determine the nop to use.
>>>   
>> Don't think that will help in general.  qemu claims its a Pentium II.
> 
> ok. I've applied Steve's patch as it's a good bugfix. The extra paranoia 
> about faulting on 0x90 seems excessive but doesnt hurt ;-)
> 

I think what we need to do is to test the NOPL instruction and create a 
Linux-specific CPUID bit for it.  I'll do that and submit to tip:x86/cpu.

	-hpa

  reply	other threads:[~2008-08-15 22:38 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-14 22:05 [PATCH] ftrace: use only 5 byte nops for x86 Steven Rostedt
2008-08-14 23:49 ` Jeremy Fitzhardinge
2008-08-15  9:22   ` Ingo Molnar
2008-08-15 22:30     ` H. Peter Anvin [this message]
2008-08-15 22:44       ` Linus Torvalds
2008-08-15 22:50         ` Jeremy Fitzhardinge
2008-08-15 22:52         ` H. Peter Anvin

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