From: Masami Hiramatsu <mhiramat@redhat.com>
To: Arjan van de Ven <arjan@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Nick Piggin <npiggin@suse.de>,
Steven Rostedt <rostedt@goodmis.org>,
Andi Kleen <andi@firstfloor.org>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Rusty Russell <rusty@rustcorp.com.au>,
"H. Peter Anvin" <hpa@zytor.com>,
Steven Rostedt <srostedt@redhat.com>
Subject: Re: [RFC][PATCH] x86: make text_poke() atomic
Date: Mon, 02 Mar 2009 14:13:35 -0500 [thread overview]
Message-ID: <49AC2FDF.9070700@redhat.com> (raw)
In-Reply-To: <20090302105500.569e1270@infradead.org>
Arjan van de Ven wrote:
> On Mon, 2 Mar 2009 13:36:17 -0500
> Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> wrote:
>
>> * Arjan van de Ven (arjan@infradead.org) wrote:
>>>> Use map_vm_area() instead of vmap() in text_poke() for avoiding
>>>> page allocation and delayed unmapping, and call
>>>> vunmap_page_range() and local_flush_tlb() directly because this
>>>> mapping is temporary and local.
>>>>
>>>> At the result of above change, text_poke() becomes atomic and can
>>>> be called from stop_machine() etc.
>>> .... but text_poke() realistically needs to call stop_machine()
>>> since you can't poke live code.... so that makes me wonder how
>>> useful this is...
>> Hi Arjan,
>>
>> Stop machine is not required when inserting a breakpoint.
>
> that is your assumption; when I spoke with CPU architects they
> cringed ;(
Is that true even if modifying just one-byte (like int3 insertion)
and we don't care synchronous write(that means code modification
effects on other processors after a while)?
Thank you,
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com
next prev parent reply other threads:[~2009-03-02 19:14 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-20 1:13 [git pull] changes for tip, and a nasty x86 page table bug Steven Rostedt
2009-02-20 1:13 ` [PATCH 1/6] x86: check PMD in spurious_fault handler Steven Rostedt
2009-02-20 1:13 ` [PATCH 2/6] x86: keep pmd rw bit set when creating 4K level pages Steven Rostedt
2009-02-20 1:13 ` [PATCH 3/6] ftrace: allow archs to preform pre and post process for code modification Steven Rostedt
2009-02-20 1:13 ` [PATCH 4/6] ftrace, x86: make kernel text writable only for conversions Steven Rostedt
2009-02-20 1:32 ` Andrew Morton
2009-02-20 1:44 ` Steven Rostedt
2009-02-20 2:05 ` [PATCH][git pull] update to tip/tracing/ftrace Steven Rostedt
2009-02-22 17:50 ` [PATCH 4/6] ftrace, x86: make kernel text writable only for conversions Andi Kleen
2009-02-22 22:53 ` Steven Rostedt
2009-02-23 0:29 ` Andi Kleen
2009-02-23 2:33 ` Mathieu Desnoyers
2009-02-23 4:29 ` Steven Rostedt
2009-02-23 4:53 ` Mathieu Desnoyers
2009-02-23 14:48 ` Steven Rostedt
2009-02-23 15:42 ` Mathieu Desnoyers
2009-02-23 15:51 ` Steven Rostedt
2009-02-23 15:55 ` Steven Rostedt
2009-02-23 16:13 ` Mathieu Desnoyers
2009-02-23 16:48 ` Steven Rostedt
2009-02-23 17:31 ` Mathieu Desnoyers
2009-02-23 18:17 ` Steven Rostedt
2009-02-23 18:34 ` Mathieu Desnoyers
2009-02-27 17:52 ` Masami Hiramatsu
2009-02-27 18:07 ` Mathieu Desnoyers
2009-02-27 18:34 ` Masami Hiramatsu
2009-02-27 18:53 ` Mathieu Desnoyers
2009-02-27 20:57 ` Masami Hiramatsu
2009-03-02 17:01 ` [RFC][PATCH] x86: make text_poke() atomic Masami Hiramatsu
2009-03-02 17:19 ` Mathieu Desnoyers
2009-03-02 22:15 ` Masami Hiramatsu
2009-03-02 22:22 ` Ingo Molnar
2009-03-02 22:55 ` Masami Hiramatsu
2009-03-02 23:09 ` Ingo Molnar
2009-03-02 23:38 ` Masami Hiramatsu
2009-03-02 23:49 ` Ingo Molnar
2009-03-03 0:00 ` Mathieu Desnoyers
2009-03-03 0:00 ` [PATCH] Text Edit Lock - Architecture Independent Code Mathieu Desnoyers
2009-03-03 0:32 ` Ingo Molnar
2009-03-03 0:39 ` Mathieu Desnoyers
2009-03-03 1:30 ` [PATCH] Text Edit Lock - Architecture Independent Code (v2) Mathieu Desnoyers
2009-03-03 1:31 ` [PATCH] Text Edit Lock - kprobes architecture independent support (v2) Mathieu Desnoyers
2009-03-03 9:27 ` Ingo Molnar
2009-03-03 12:06 ` Ananth N Mavinakayanahalli
2009-03-03 14:28 ` Mathieu Desnoyers
2009-03-03 14:33 ` [PATCH] Text Edit Lock - kprobes architecture independent support (v3) Mathieu Desnoyers
2009-03-03 14:53 ` [PATCH] Text Edit Lock - kprobes architecture independent support (v2) Ingo Molnar
2009-03-03 0:01 ` [PATCH] Text Edit Lock - kprobes architecture independent support Mathieu Desnoyers
2009-03-03 0:10 ` Masami Hiramatsu
2009-03-03 0:05 ` [RFC][PATCH] x86: make text_poke() atomic Masami Hiramatsu
2009-03-03 0:22 ` Ingo Molnar
2009-03-03 0:31 ` Masami Hiramatsu
2009-03-03 16:31 ` [PATCH] x86: make text_poke() atomic using fixmap Masami Hiramatsu
2009-03-03 17:08 ` Mathieu Desnoyers
2009-03-05 10:38 ` Ingo Molnar
2009-03-06 14:06 ` Ingo Molnar
2009-03-06 14:49 ` Masami Hiramatsu
2009-03-02 18:28 ` [RFC][PATCH] x86: make text_poke() atomic Arjan van de Ven
2009-03-02 18:36 ` Mathieu Desnoyers
2009-03-02 18:55 ` Arjan van de Ven
2009-03-02 19:13 ` Masami Hiramatsu [this message]
2009-03-02 19:23 ` H. Peter Anvin
2009-03-02 19:47 ` Mathieu Desnoyers
2009-03-02 18:42 ` Linus Torvalds
2009-03-03 4:54 ` Nick Piggin
2009-02-23 18:23 ` [PATCH 4/6] ftrace, x86: make kernel text writable only for conversions Steven Rostedt
2009-02-23 9:02 ` Ingo Molnar
2009-02-27 21:08 ` Pavel Machek
2009-02-28 16:56 ` Andi Kleen
2009-02-28 22:08 ` Pavel Machek
[not found] ` <87wsba1a9f.fsf@basil.nowhere.org>
2009-02-28 22:19 ` Pavel Machek
2009-02-28 23:52 ` Andi Kleen
2009-02-20 1:13 ` [PATCH 5/6] ftrace: immediately stop code modification if failure is detected Steven Rostedt
2009-02-20 1:13 ` [PATCH 6/6] ftrace: break out modify loop immediately on detection of error Steven Rostedt
2009-02-20 2:00 ` [git pull] changes for tip, and a nasty x86 page table bug Linus Torvalds
2009-02-20 2:08 ` Steven Rostedt
2009-02-20 3:44 ` Linus Torvalds
2009-02-20 4:00 ` Steven Rostedt
2009-02-20 4:17 ` Linus Torvalds
2009-02-20 4:34 ` Steven Rostedt
2009-02-20 5:02 ` Huang Ying
2009-02-20 7:29 ` [PATCH] x86: use the right protections for split-up pagetables Ingo Molnar
2009-02-20 7:39 ` [PATCH, v2] " Ingo Molnar
2009-02-20 8:02 ` Ingo Molnar
2009-02-20 10:24 ` Ingo Molnar
2009-02-20 13:57 ` [PATCH] " Steven Rostedt
2009-02-20 15:40 ` Linus Torvalds
2009-02-20 16:59 ` Ingo Molnar
2009-02-20 18:33 ` H. Peter Anvin
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