From: Andi Kleen <ak@suse.de>
To: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Andi Kleen <ak@suse.de>, Karim Yaghmour <karim@opersys.com>,
Masami Hiramatsu <masami.hiramatsu@gmail.com>,
Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>,
Roland McGrath <roland@redhat.com>,
Richard J Moore <richardj_moore@uk.ibm.com>,
systemtap@sources.redhat.com, sugita@sdl.hitachi.co.jp,
Satoshi Oshima <soshima@redhat.com>,
michel.dagenais@polymtl.ca
Subject: Re: Hitachi djprobe mechanism
Date: Sat, 30 Jul 2005 15:55:00 -0000 [thread overview]
Message-ID: <20050730155526.GH3726@bragg.suse.de> (raw)
In-Reply-To: <20050729155025.GA357@Krystal>
> As I see it, the write in memory is atomic, but not the instruction fetching. In
> that case, the reader would see an inconsistent last jmp address byte.
Yes, you're right. cmpxchg only helps when the replaced instruction
is >= the new instruction. For smaller instructions only a IPI to
stop all CPUs works.
Actually there may be tricks possible to first int3 (or equivalent single
byte replacement on other archs) the second instruction,
then the first, then wait for a RCU period of all CPUs to quiescence and then
write the longer jump. But an IPI is probably easier because it doesn't need
a full disassembler for this and setting probes should not be performance
critical.
-Andi
next prev parent reply other threads:[~2005-07-30 15:55 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-27 21:05 Keshavamurthy, Anil S
2005-07-28 1:51 ` Karim Yaghmour
2005-07-28 2:10 ` Karim Yaghmour
2005-07-28 16:23 ` Masami Hiramatsu
2005-07-28 16:28 ` Karim Yaghmour
2005-07-28 17:36 ` Mathieu Desnoyers
[not found] ` <20050728110717.A30199@unix-os.sc.intel.com>
2005-07-28 18:33 ` Mathieu Desnoyers
[not found] ` <20050728133456.A32210@unix-os.sc.intel.com>
2005-07-28 23:53 ` Richard J Moore
2005-07-29 5:59 ` Mathieu Desnoyers
2005-07-29 7:55 ` Andi Kleen
2005-07-29 8:44 ` Richard J Moore
2005-07-29 8:46 ` Andi Kleen
2005-07-29 15:51 ` Mathieu Desnoyers
2005-07-30 15:55 ` Andi Kleen [this message]
2005-07-30 16:54 ` Mathieu Desnoyers
2005-07-31 22:03 ` Andi Kleen
2005-07-31 23:11 ` Mathieu Desnoyers
2005-08-01 15:37 ` Andi Kleen
2005-08-01 8:44 ` Richard J Moore
2005-08-01 13:21 ` Mathieu Desnoyers
2005-08-01 19:57 ` Satoshi Oshima
2005-08-01 20:21 ` Karim Yaghmour
2005-08-01 22:12 ` Satoshi Oshima
2005-08-01 22:54 ` Karim Yaghmour
2005-08-02 18:42 ` Satoshi Oshima
2005-08-03 14:50 ` Karim Yaghmour
2005-08-04 1:19 ` Mathieu Desnoyers
2005-08-04 3:31 ` Mathieu Desnoyers
2005-08-02 9:42 ` Mathieu Lacage
2005-08-02 15:09 ` Karim Yaghmour
2005-10-07 15:35 ` Richard J Moore
2005-10-08 18:33 ` mathieu lacage
2005-10-08 21:59 ` Richard J Moore
2005-10-08 23:24 ` Roland McGrath
2005-10-22 11:49 ` mathieu lacage
2005-10-22 22:09 ` Roland McGrath
2005-10-24 6:33 ` Mathieu Lacage
2005-10-24 19:48 ` Roland McGrath
[not found] ` <43621B0D.70204@sophia.inria.fr>
2005-11-07 10:04 ` mathieu lacage
2005-11-07 10:06 ` mathieu lacage
2005-11-08 9:49 ` Richard J Moore
2005-10-09 16:47 ` mathieu lacage
2005-08-02 15:33 ` Mathieu Lacage
2005-08-02 15:36 ` Mathieu Lacage
2005-08-02 16:12 ` Karim Yaghmour
2005-08-02 16:30 ` Mathieu Lacage
2005-08-02 16:46 ` Karim Yaghmour
2005-08-04 17:09 ` Mathieu Lacage
2005-08-03 14:46 ` Andi Kleen
2005-07-29 16:06 ` Frank Ch. Eigler
2005-07-29 18:24 ` sugita
2005-07-28 18:13 ` Richard J Moore
-- strict thread matches above, loose matches on Subject: below --
2005-08-01 22:49 Keshavamurthy, Anil S
2005-08-01 23:05 ` Karim Yaghmour
2005-08-01 23:18 ` Karim Yaghmour
2005-08-01 22:41 Keshavamurthy, Anil S
2005-08-02 3:21 ` Roland McGrath
2005-08-02 3:35 ` Karim Yaghmour
2005-08-01 20:46 Keshavamurthy, Anil S
2005-08-01 21:08 ` Karim Yaghmour
2005-08-01 16:14 Keshavamurthy, Anil S
2005-08-01 20:31 ` Roland McGrath
2005-08-04 0:28 ` Mathieu Desnoyers
2005-08-04 10:01 ` Andi Kleen
2005-08-05 16:25 ` Mathieu Desnoyers
2005-08-05 16:39 ` Andi Kleen
2005-08-01 15:50 Keshavamurthy, Anil S
2005-08-01 16:03 ` Mathieu Desnoyers
2005-07-29 0:18 Keshavamurthy, Anil S
2005-07-29 1:48 ` Karim Yaghmour
2005-07-29 3:41 ` Mathieu Desnoyers
2005-07-29 3:47 ` Karim Yaghmour
2005-07-29 1:53 ` Frank Ch. Eigler
2005-08-01 9:02 ` Mathieu Lacage
2005-08-01 13:18 ` Mathieu Desnoyers
2005-08-02 7:07 ` Mathieu Lacage
2005-07-22 18:09 Frank Ch. Eigler
2005-07-21 22:32 Richard J Moore
2005-07-21 22:52 ` Roland McGrath
2005-07-22 2:52 ` Richard J Moore
2005-07-26 7:14 ` Masami Hiramatsu
2005-07-26 7:53 ` Roland McGrath
2005-07-27 13:02 ` Masami Hiramatsu
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