From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: "David P. Reed" <dpreed@reed.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: RFC: do get_rtc_time() correctly
Date: Thu, 16 Aug 2007 11:05:47 +0100 [thread overview]
Message-ID: <20070816110547.166d96e5@the-village.bc.nu> (raw)
In-Reply-To: <46C399C1.9000502@reed.com>
> I understand that SMM/SMI servicing can take a long time, but SMM/SMI
> shouldn't happen while interrupts are masked using local_irq_disable()
Don't bet on it.
> [included in spin_lock_irq()], at least on x86-architectures. If
> SMM/SMI can happen even then, the NMI fix below could be generalized.
>
> My mention of NMI (which by definition can't be masked) is because NMI
On x86 you can mask NMI briefly if you are willing to do a bit of CPU
abuse. Force an NMI, longjmp out of the handler, and NMI is off until the
next iret instruction or similar.
We don't do this and I think Linus would object to anyone who did 8)
next prev parent reply other threads:[~2007-08-16 9:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-15 19:22 David P. Reed
2007-08-15 23:51 ` Alan Cox
2007-08-16 0:26 ` David P. Reed
2007-08-16 0:54 ` Rene Herman
2007-08-16 10:05 ` Alan Cox [this message]
2007-08-16 0:15 ` H. Peter Anvin
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