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From: Jamie Lokier <lk@tantalophile.demon.co.uk>
To: Andi Kleen <ak@suse.de>
Cc: Linus Torvalds <torvalds@transmeta.com>, linux-kernel@vger.kernel.org
Subject: Re: context switch vs. signal delivery [was: Re: Accelerating user  mode linux]
Date: Mon, 5 Aug 2002 22:30:06 +0100	[thread overview]
Message-ID: <20020805223006.A8773@kushida.apsleyroad.org> (raw)
In-Reply-To: <p73znw1i781.fsf@oldwotan.suse.de>; from ak@suse.de on Mon, Aug 05, 2002 at 06:46:38PM +0200

A couple of questions.

Andi Kleen wrote:
> +	err |= setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0], 
> +				(ka->sa.sa_flags&SA_NOFP));

>  	err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
> -			        regs, set->sig[0]);
> +			        regs, set->sig[0], !!(ka->sa.sa_flags&SA_NOFP));

1: Why the inconsistency between the two ways the SA_NOFP flag is checked?

2: What happens when the user's signal handler decides it wants to save
the FPU state itself (after all) and proceed with some FPU use.  Will
sigreturn restore the user-saved FPU state?  Just curious.

-- Jamie

  reply	other threads:[~2002-08-05 21:26 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20020805163910.C7130@kushida.apsleyroad.org.suse.lists.linux.kernel>
     [not found] ` <Pine.LNX.4.44.0208050922570.1753-100000@home.transmeta.com.suse.lists.linux.kernel>
2002-08-05 16:46   ` Andi Kleen
2002-08-05 21:30     ` Jamie Lokier [this message]
2002-08-05 21:35       ` Andi Kleen
2002-08-05 22:09         ` Jamie Lokier
2002-08-05 22:16           ` Andi Kleen
     [not found] <1028294887.18635.71.camel@irongate.swansea.linux.org.uk.suse.lists.linux.kernel>
     [not found] ` <Pine.LNX.4.44.0208031332120.7531-100000@localhost.localdomain.suse.lists.linux.kernel>
     [not found]   ` <m3u1mb5df3.fsf@averell.firstfloor.org.suse.lists.linux.kernel>
     [not found]     ` <ail2qh$bf0$1@penguin.transmeta.com.suse.lists.linux.kernel>
2002-08-05  8:38       ` Andi Kleen
2002-08-05 14:24         ` Jeff Dike
2002-08-05 16:19         ` Linus Torvalds
2002-08-02 13:28 Accelerating user mode linux Alan Cox
2002-08-03 11:38 ` context switch vs. signal delivery [was: Re: Accelerating user mode linux] Ingo Molnar
2002-08-04  6:46   ` Andi Kleen
2002-08-05  5:35     ` Linus Torvalds
2002-08-05  5:42       ` Arnaldo Carvalho de Melo
2002-08-05  6:37       ` Lincoln Dale
2002-08-05 15:39       ` Jamie Lokier
2002-08-05 16:38         ` Linus Torvalds
2002-08-06  5:31       ` Mark Mielke
2002-08-05 10:40     ` Ingo Molnar
2002-08-05 14:59       ` Larry McVoy
2002-08-05 15:41       ` Jamie Lokier
2002-08-05 15:44         ` Jamie Lokier

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