From: "H. Peter Anvin" <hpa@zytor.com>
To: Jason Baron <jbaron@redhat.com>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu,
mathieu.desnoyers@polymtl.ca, tglx@linutronix.de,
rostedt@goodmis.org, andi@firstfloor.org, roland@redhat.com,
rth@redhat.com, mhiramat@redhat.com
Subject: Re: [RFC PATCH 0/6] jump label v3
Date: Wed, 18 Nov 2009 14:51:45 -0800 [thread overview]
Message-ID: <4B047A81.3060104@zytor.com> (raw)
In-Reply-To: <cover.1258580048.git.jbaron@redhat.com>
On 11/18/2009 02:43 PM, Jason Baron wrote:
>
> I'm using an atomic 5 byte no-op for x86_64 and a long jump for 32-bit x86.
> My understanding is that not all 32-bit processors have an atomic 5 byte no-op,
> and thus using a long jump or jump 0, for the off case is the safest.
>
67 66 8D 74 00 (lea si,[si+0]) should work as a 32-bit atomic NOP. It's
not necessarily the fastest, though (I have no data on that.)
Similarly, 66 66 66 66 90 should also work.
-hpa
next prev parent reply other threads:[~2009-11-18 22:52 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-18 22:43 Jason Baron
2009-11-18 22:43 ` [RFC PATCH 1/6] jump label v3 - kprobes/x86: Cleanup RELATIVEJUMP_INSTRUCTION to RELATIVEJUMP_OPCODE Jason Baron
2009-11-18 22:43 ` [RFC PATCH 2/6] jump label v3 - x86: Introduce generic jump patching without stop_machine Jason Baron
2009-11-19 0:28 ` Mathieu Desnoyers
2009-11-19 0:58 ` Paul E. McKenney
2009-11-19 1:22 ` Steven Rostedt
2009-11-19 1:39 ` Paul E. McKenney
2009-11-19 1:57 ` Mathieu Desnoyers
2009-11-19 4:16 ` Paul E. McKenney
2009-11-19 14:04 ` Masami Hiramatsu
2009-11-19 16:03 ` Mathieu Desnoyers
2009-11-20 1:00 ` Masami Hiramatsu
2009-11-21 15:32 ` Mathieu Desnoyers
2009-11-21 1:11 ` Masami Hiramatsu
2009-11-21 15:38 ` Mathieu Desnoyers
2009-11-20 21:54 ` H. Peter Anvin
2009-11-21 0:06 ` Masami Hiramatsu
2009-11-21 0:19 ` H. Peter Anvin
2009-11-21 16:21 ` Mathieu Desnoyers
2009-11-21 21:55 ` Masami Hiramatsu
2009-11-22 1:46 ` Mathieu Desnoyers
2009-11-21 16:12 ` Mathieu Desnoyers
2009-11-18 22:43 ` [RFC PATCH 3/6] jump label v3 - move opcode defs Jason Baron
2009-11-18 22:43 ` [RFC PATCH 4/6] jump label v3 - base patch Jason Baron
2009-11-18 23:38 ` [PATCH] notifier atomic call chain notrace Mathieu Desnoyers
2009-11-19 0:02 ` Paul E. McKenney
2009-11-19 3:59 ` Masami Hiramatsu
2009-11-19 16:48 ` Jason Baron
2009-11-18 22:43 ` [RFC PATCH 5/6] jump label v3 - add module support Jason Baron
2009-11-18 22:43 ` [RFC PATCH 6/6] jump label v3 - tracepoint support Jason Baron
2009-11-18 22:51 ` H. Peter Anvin [this message]
2009-11-18 23:07 ` [RFC PATCH 0/6] jump label v3 Roland McGrath
2009-11-18 23:18 ` H. Peter Anvin
2009-11-19 3:54 ` Roland McGrath
2009-11-19 21:55 ` Jason Baron
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