From: Brian Gerst <bgerst@didntduck.org>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: nigel@nrg.org, Alan Cox <alan@lxorguk.ukuu.org.uk>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86 page fault handler not interrupt safe
Date: Mon, 07 May 2001 18:10:03 -0400 [thread overview]
Message-ID: <3AF71D3B.E4D0AFFB@didntduck.org> (raw)
In-Reply-To: <Pine.LNX.4.31.0105071443080.1195-100000@penguin.transmeta.com>
Linus Torvalds wrote:
>
> On Mon, 7 May 2001, Brian Gerst wrote:
> >
> > Keep in mind that regs->eflags could be from user space, and could have
> > some undesirable flags set. That's why I did a test/sti instead of
> > reloading eflags. Plus my patch leaves interrupts disabled for the
> > minimum time possible.
>
> The plain "popf" should be ok: the way intel works, you cannot actually
> use popf to set any of the strange flags (if vm86 mode etc).
TF (trap flag) would be one that I wouldn't want to get reset. You
could use
local_irq_restore(regs->eflags & ~(TF|RF|VM|NT))
which are all the flags cleared by an interrupt/trap gate. Or
if (regs->eflags & IF) sti();
Take your pick.
--
Brian Gerst
next prev parent reply other threads:[~2001-05-07 22:11 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <3AF712D5.5D712E0F@didntduck.org>
2001-05-07 21:44 ` [PATCH] x86 page fault handler not interrupt safe Linus Torvalds
2001-05-07 22:10 ` Brian Gerst [this message]
2001-05-08 10:45 ` Alan Cox
2001-05-08 16:45 ` Linus Torvalds
2001-05-09 22:12 ` Brian Gerst
2001-05-07 21:53 ` Nigel Gamble
2001-05-07 21:58 Anton Altaparmakov
[not found] <D5E932F578EBD111AC3F00A0C96B1E6F07DBE26F@orsmsx31.jf.intel .com>
2001-05-07 17:52 ` Anton Altaparmakov
-- strict thread matches above, loose matches on Subject: below --
2001-05-07 17:32 Dunlap, Randy
2001-05-07 17:51 ` David Woodhouse
2001-05-06 1:26 Brian Gerst
2001-05-07 0:53 ` Linus Torvalds
2001-05-07 3:54 ` Brian Gerst
2001-05-07 10:45 ` Alan Cox
2001-05-07 14:57 ` Brian Gerst
2001-05-07 15:07 ` Alan Cox
2001-05-07 17:12 ` Linus Torvalds
2001-05-07 17:27 ` David Woodhouse
2001-05-07 19:54 ` Brian Gerst
2001-05-07 20:16 ` Linus Torvalds
2001-05-07 21:37 ` Alan Cox
2001-05-07 22:52 ` Jesper Juhl
2001-05-07 18:35 ` Anton Altaparmakov
2001-05-07 16:51 ` Linus Torvalds
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