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From: Andrea Arcangeli <andrea@suse.de>
To: Andreas Jaeger <aj@suse.de>
Cc: Andi Kleen <ak@muc.de>, Jeff Dike <jdike@karaya.com>,
	john stultz <johnstul@us.ibm.com>,
	Linus Torvalds <torvalds@transmeta.com>,
	lkml <linux-kernel@vger.kernel.org>,
	george anzinger <george@mvista.com>,
	Stephen Hemminger <shemminger@osdl.org>,
	discuss@x86-64.org
Subject: Re: [PATCH] linux-2.5.43_vsyscall_A0
Date: Sun, 20 Oct 2002 16:59:19 +0200	[thread overview]
Message-ID: <20021020145919.GU23930@dualathlon.random> (raw)
In-Reply-To: <u8lm4tcknv.fsf@gromit.moeb>

On Sun, Oct 20, 2002 at 03:19:32PM +0200, Andreas Jaeger wrote:
> Andi Kleen <ak@muc.de> writes:
> 
> > [full quote for context]
> >
> > On Sat, Oct 19, 2002 at 06:49:59AM +0200, Jeff Dike wrote:
> >> ak@muc.de said:
> >> > Guess you'll have some problems then with UML on x86-64, which always
> >> > uses vgettimeofday. But it's only used for gettimeofday() currently,
> >> > perhaps it's  not that bad when the UML child runs with the host's
> >> > time.
> >> 
> >> It's not horrible, but it's still broken.  There are people who depend
> >> on UML being able to keep its own time separately from the host.
> >> 
> >> > I guess it would be possible to add some support for UML to map own
> >> > code over the vsyscall reserved locations. UML would need to use the
> >> > syscalls then. But it'll be likely ugly. 
> >> 
> >> Yeah, it would be.
> >> 
> >> My preferred solution would be for libc to ask the kernel where the vsyscall
> >> area is.  That's reasonably clean and virtualizable.  Andrea doesn't like it
> >> because it adds a few instructions to the vsyscall address calculation.
> >
> > I would have no problems with adding that to the x86-64 kernel. It could
> > be passed in by the ELF environment vector and added to the ABI. 
> > Overhead should be negligible, it just needs a single table lookup.  
> > Andreas, what do you think ? 
> 
> Create a new AT_ constant, and pass it via the auxiliary vector and we
> can use it in glibc.

will it be a pointer to function?

Andrea

  reply	other threads:[~2002-10-20 14:53 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-10-18 22:57 [PATCH] linux-2.5.43_vsyscall_A0 john stultz
2002-10-18 22:58 ` [EXAMPLE CODE] linux-2.5.43_vsyscall_A0 john stultz
2002-10-19  3:52 ` [PATCH] linux-2.5.43_vsyscall_A0 Jeff Dike
2002-10-19  3:10   ` Andi Kleen
2002-10-19  4:49     ` Jeff Dike
2002-10-19  4:02       ` Andi Kleen
2002-10-19  4:16         ` Andrea Arcangeli
2002-10-20  2:59           ` Andi Kleen
2002-10-20  6:44             ` Elladan
2002-10-20  9:27               ` [discuss] " Andi Kleen
2002-10-20 10:58                 ` Elladan
2002-10-20 11:20                   ` Andi Kleen
2002-10-20 14:51             ` Andrea Arcangeli
2002-10-21 16:49               ` george anzinger
2002-10-20 13:19         ` Andreas Jaeger
2002-10-20 14:59           ` Andrea Arcangeli [this message]
2002-10-19  4:10       ` Andrea Arcangeli
2002-10-19  4:45         ` Andi Kleen
2002-10-19  5:01           ` Andrea Arcangeli
2002-10-19 23:43             ` Jeff Dike
2002-10-20  0:15               ` Andrea Arcangeli
2002-10-20  2:03                 ` Jeff Dike
2002-10-20  2:33                   ` Andrea Arcangeli
2002-10-22  5:07                     ` Jeff Dike
2002-10-22  4:15                       ` Andi Kleen
2002-10-22  4:29                         ` Andrew Morton
2002-10-22  9:39                           ` Alan Cox
2002-10-22 16:12                             ` Andrew Morton
2002-10-22  5:08                         ` Andrea Arcangeli
2002-10-22  5:27                       ` Andrea Arcangeli
2002-10-22  7:24                         ` Elladan
2002-10-22  7:40                           ` Andrea Arcangeli
2002-10-23  5:12                             ` Elladan
2002-10-23  5:43                               ` Elladan
2002-10-23 17:51                               ` Gerrit Huizenga
2002-10-21 15:43             ` Stephen Hemminger
2002-10-21 16:26               ` Andi Kleen
2002-10-21 17:10           ` john stultz
2002-10-19 19:14         ` Bill Davidsen
2002-10-20  1:50       ` Rik van Riel
2002-10-20  2:56         ` Andi Kleen
2002-10-24 11:24       ` Pavel Machek
2002-10-24 11:24     ` Pavel Machek
2002-10-19 22:36   ` Ton Hospel

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