From: John Sigler <linux.kernel@free.fr>
To: linux-kernel@vger.kernel.org
Cc: Andi Kleen <andi@firstfloor.org>, linux.kernel@free.fr
Subject: Re: Disabling x86 System Management Mode
Date: Wed, 18 Apr 2007 10:09:29 +0200 [thread overview]
Message-ID: <4625D239.90801@free.fr> (raw)
In-Reply-To: <4624FA85.9010704@free.fr>
John Sigler wrote:
> # : >/var/log/kern.log; cat /proc/interrupts; /bin/time insmod houba.ko;
> cat /proc/interrupts; rmmod houba
> CPU0
> 0: 519083 XT-PIC-XT timer
> 2: 0 XT-PIC-XT cascade
> 9: 0 XT-PIC-XT acpi
> 10: 9786 XT-PIC-XT eth0
> 11: 5 XT-PIC-XT eth1
> 12: 5 XT-PIC-XT eth2
> 14: 16920 XT-PIC-XT ide0
> NMI: 0
> ERR: 0
> 0.00user 0.00system 5:00.00elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (0major+111minor)pagefaults 0swaps
> CPU0
> 0: 549094 XT-PIC-XT timer
> 2: 0 XT-PIC-XT cascade
> 9: 0 XT-PIC-XT acpi
> 10: 9791 XT-PIC-XT eth0
> 11: 5 XT-PIC-XT eth1
> 12: 5 XT-PIC-XT eth2
> 14: 16970 XT-PIC-XT ide0
> NMI: 0
> ERR: 0
>
> (HZ=100)
> 30011 timer interrupts
> 5 eth0 interrupts
> 50 ide0 interrupts
>
> # cat /var/log/kern.log
> Apr 17 18:22:27 SEND kernel: INIT
> Apr 17 18:27:27 SEND kernel: 2350080 29995
> Apr 17 18:27:27 SEND kernel: 2369792 1
> Apr 17 18:27:27 SEND kernel: 2440192 1
> Apr 17 18:27:27 SEND kernel: 2441216 1
> Apr 17 18:27:27 SEND kernel: 2583296 1
> Apr 17 18:27:27 SEND kernel: 2852096 1
> Apr 17 18:27:27 SEND kernel: EXIT
>
> First column is the cycle count clamped to a multiple of 256.
> (1266.7 MHz CPU)
> Second column is occurence count.
>
> In the second experiment, I added the IRQ disable/enable around foo.
>
> # : >/var/log/kern.log; cat /proc/interrupts; /bin/time insmod houba.ko;
> cat /proc/interrupts; rmmod houba
> CPU0
> 0: 583666 XT-PIC-XT timer
> 2: 0 XT-PIC-XT cascade
> 9: 0 XT-PIC-XT acpi
> 10: 10084 XT-PIC-XT eth0
> 11: 5 XT-PIC-XT eth1
> 12: 5 XT-PIC-XT eth2
> 14: 17012 XT-PIC-XT ide0
> NMI: 0
> ERR: 0
> 0.00user 0.01system 5:00.00elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (0major+110minor)pagefaults 0swaps
> CPU0
> 0: 613677 XT-PIC-XT timer
> 2: 0 XT-PIC-XT cascade
> 9: 0 XT-PIC-XT acpi
> 10: 10089 XT-PIC-XT eth0
> 11: 5 XT-PIC-XT eth1
> 12: 5 XT-PIC-XT eth2
> 14: 17070 XT-PIC-XT ide0
> NMI: 0
> ERR: 0
>
> 30011 timer interrupts
> 5 eth0 interrupts
> 58 ide0 interrupts
>
> # cat /var/log/kern.log
> Apr 17 18:33:12 SEND kernel: INIT
> Apr 17 18:38:12 SEND kernel: 2350080 30000
> Apr 17 18:38:12 SEND kernel: EXIT
>
> In this experiment, all the calls to foo had a latency between
> 2350080 and 2350335 cycles (1.88528 to 1.88548 ms).
>
> I don't think I can conclude anything based on this experiment.
>
> I'll let it run all night long.
With the IRQ disable/enable around foo:
# : >/var/log/kern.log; cat /proc/interrupts; /bin/time insmod houba.ko;
cat /proc/interrupts; rmmod houba
CPU0
0: 14659 XT-PIC-XT timer
2: 0 XT-PIC-XT cascade
9: 0 XT-PIC-XT acpi
10: 144 XT-PIC-XT eth0
11: 5 XT-PIC-XT eth1
12: 5 XT-PIC-XT eth2
14: 21526 XT-PIC-XT ide0
NMI: 0
ERR: 0
0.00user 0.01system 12:30:00elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+110minor)pagefaults 0swaps
CPU0
0: 4516164 XT-PIC-XT timer
2: 0 XT-PIC-XT cascade
9: 0 XT-PIC-XT acpi
10: 414 XT-PIC-XT eth0
11: 5 XT-PIC-XT eth1
12: 5 XT-PIC-XT eth2
14: 21620 XT-PIC-XT ide0
NMI: 0
ERR: 0
4501505 timer interrupts (I had set N to 4500000)
270 eth0 interrupts
94 ide0 interrupts
# cat /var/log/kern.log
Apr 17 19:03:26 SEND kernel: INIT
Apr 18 07:33:26 SEND kernel: 2350080 4500000
Apr 18 07:33:26 SEND kernel: EXIT
I'd say the CPU does not appear to enter SMM on this system.
(Unless the SMI handler restores the TSC as suggested by Andi.)
I need to refine my detection code.
next prev parent reply other threads:[~2007-04-18 8:09 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-16 10:47 Disabling x86 System Management Mode John
2007-04-16 11:31 ` John
2007-04-16 15:12 ` Lee Revell
2007-04-16 22:12 ` Andi Kleen
2007-04-17 16:49 ` John Sigler
2007-04-17 16:57 ` Andi Kleen
2007-04-17 21:32 ` John Sigler
2007-04-17 17:01 ` John Sigler
2007-04-18 8:09 ` John Sigler [this message]
2007-04-18 11:41 ` John Sigler
2007-04-18 14:06 ` Andrew Shewmaker
2007-04-18 14:39 ` John Sigler
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