From: Ingo Molnar <mingo@elte.hu>
To: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Linus Torvalds <torvalds@osdl.org>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Lee Revell <rlrevell@joe-job.com>,
Andrea Arcangeli <andrea@suse.de>,
Manfred Spraul <manfred@colorfullife.com>,
Zwane Mwaikambo <zwane@arm.linux.org.uk>,
George Anzinger <george@mvista.com>,
dipankar@in.ibm.com, ganzinger@mvista.com,
lkml <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>, Andi Kleen <ak@suse.de>
Subject: Re: [patch, 2.6.10-rc3] safe_hlt() & NMIs
Date: Thu, 16 Dec 2004 16:11:26 +0100 [thread overview]
Message-ID: <20041216151126.GA17066@elte.hu> (raw)
In-Reply-To: <Pine.LNX.4.58L.0412161501190.15472@blysk.ds.pg.gda.pl>
* Maciej W. Rozycki <macro@linux-mips.org> wrote:
> On Thu, 16 Dec 2004, Ingo Molnar wrote:
>
> > c0125ee9: 1529 fa cli
> > ^---------------------------------- # of profiler hits
> > c0125eea: 507 fb sti
> > c0125eeb: 0 fa cli
> > c0125eec: 3719 fb sti
> > c0125eed: 0 fa cli
> > c0125eee: 1579 fb sti
> > c0125eef: 0 fa cli
> > c0125ef0: 3317 fb sti
> > c0125ef1: 0 fa cli
> > c0125ef2: 3030 fb sti
> > c0125ef3: 0 fa cli
> > c0125ef4: 2497 fa cli
> > c0125ef5: 1055 fb sti
> > c0125ef6: 0 fa cli
> [...]
> > the 'cli' is always a 'black hole' to the NMI, while the second of two
> > consecutive cli's are not.
>
> It looks like the 'sti' is actually the black hole -- remember
> interrupts are traps, that is they are probed for and taken after
> instruction execution.
The 'sti' "shadows" the cli, i.e. we'll never get an interrupt that gets
inbetween 'sti;cli'. I.e. sti is the black-hole generator, and 'cli' is
in the black hole. In that sense the 'cli' is in a black hole to the
NMI: the NMI will never see cli as the 'next to be executed'
instruction.
Ingo
next prev parent reply other threads:[~2004-12-16 15:13 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-09 23:59 RCU question George Anzinger
2004-12-10 4:31 ` Dipankar Sarma
2004-12-10 19:42 ` George Anzinger
2004-12-10 20:40 ` Dipankar Sarma
2004-12-10 20:45 ` Lee Revell
2004-12-10 21:02 ` George Anzinger
2004-12-10 22:58 ` Zwane Mwaikambo
2004-12-11 2:22 ` George Anzinger
2004-12-11 2:45 ` Zwane Mwaikambo
2004-12-11 3:29 ` George Anzinger
2004-12-11 14:52 ` Zwane Mwaikambo
2004-12-11 16:32 ` Manfred Spraul
2004-12-11 16:52 ` George Anzinger
2004-12-12 2:53 ` Zwane Mwaikambo
2004-12-12 8:59 ` Manfred Spraul
2004-12-12 9:37 ` Andrea Arcangeli
2004-12-12 10:22 ` Manfred Spraul
2004-12-12 12:15 ` Andrea Arcangeli
2004-12-14 21:40 ` Lee Revell
2004-12-14 22:23 ` [patch, 2.6.10-rc3] safe_hlt() & NMIs Ingo Molnar
2004-12-14 22:47 ` Ingo Molnar
2004-12-14 23:09 ` Linus Torvalds
2004-12-15 8:52 ` Ingo Molnar
2004-12-15 15:44 ` Linus Torvalds
2004-12-15 16:35 ` Ingo Molnar
2004-12-16 0:37 ` Alan Cox
2004-12-16 1:58 ` Linus Torvalds
2004-12-16 14:51 ` Ingo Molnar
2004-12-16 15:08 ` Maciej W. Rozycki
2004-12-16 15:11 ` Ingo Molnar [this message]
2004-12-16 15:42 ` Maciej W. Rozycki
2004-12-16 15:54 ` Linus Torvalds
2004-12-16 2:10 ` Zwane Mwaikambo
2004-12-16 13:26 ` Alan Cox
2004-12-14 23:41 ` Andrea Arcangeli
2004-12-14 23:00 ` Linus Torvalds
2004-12-15 5:04 ` Andi Kleen
2004-12-15 6:27 ` Avi Kivity
2004-12-15 8:51 ` Ingo Molnar
2004-12-12 16:51 ` RCU question George Anzinger
2004-12-12 22:40 ` Manfred Spraul
2004-12-13 5:22 ` George Anzinger
2004-12-12 16:26 ` Zwane Mwaikambo
-- strict thread matches above, loose matches on Subject: below --
2004-12-17 23:35 [patch, 2.6.10-rc3] safe_hlt() & NMIs Chuck Ebbert
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