Re: [PATCH] x86 page fault handler not interrupt safe

[Brian Gerst <bgerst@didntduck.org>]

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