From: Andi Kleen <ak@suse.de>
To: Elladan <elladan@eskimo.com>
Cc: Andi Kleen <ak@muc.de>, Andrea Arcangeli <andrea@suse.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, aj@suse.de
Subject: Re: [discuss] Re: [PATCH] linux-2.5.43_vsyscall_A0
Date: Sun, 20 Oct 2002 11:27:30 +0200 [thread overview]
Message-ID: <20021020112730.A29357@wotan.suse.de> (raw)
In-Reply-To: <20021020064433.GA32594@eskimo.com>
On Sat, Oct 19, 2002 at 11:44:33PM -0700, Elladan wrote:
> The problem with modifying the executable code/pages in the vsyscall
> area is that it's going to be very tricky to implement, if I understand
> this discussion properly.
Modifying the pages or variables in the pages from the kernel is no
problem. It just would affect all processes on the system
What's tricky is to give it per process state (which would
be needed to make a vsyscall/novsyscall flag process local)
>
> There may be any number of user processes idling in these pages on the
> runqueue (or off it if say one received a SIGSTOP), and if you just go
> change the instruction code on them, unless you're incredibly careful
> and come up with some subtly safe machine code sequence, they're going
> crash when you call this sysctl().
Nobody proposed to use self modifying code, it would just be a global
variable located in the vsyscall area that is tested by the vsyscall
code.
-Andi
next prev parent reply other threads:[~2002-10-20 9:21 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 ` Andi Kleen [this message]
2002-10-20 10:58 ` [discuss] " 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
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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