From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Albert Cahalan <albert@users.sf.net>
Cc: Christoph Lameter <clameter@sgi.com>,
Albert Cahalan <albert@users.sourceforge.net>,
Matt Mackall <mpm@selenic.com>, john stultz <johnstul@us.ibm.com>,
lkml <linux-kernel@vger.kernel.org>,
Tim Schmielau <tim@physik3.uni-rostock.de>,
George Anzinger <george@mvista.com>,
Ulrich Windl <ulrich.windl@rz.uni-regensburg.de>,
Dominik Brodowski <linux@dominikbrodowski.de>,
David Mosberger <davidm@hpl.hp.com>, Andi Kleen <ak@suse.de>,
paulus@samba.org, schwidefsky@de.ibm.com,
keith maanthey <kmannth@us.ibm.com>,
Patricia Gaughen <gone@us.ibm.com>,
Chris McDermott <lcm@us.ibm.com>, Max Asbock <masbock@us.ibm.com>,
mahuja@us.ibm.com, Nishanth Aravamudan <nacc@us.ibm.com>,
Darren Hart <darren@dvhart.com>,
"Darrick J. Wong" <djwong@us.ibm.com>,
Anton Blanchard <anton@samba.org>,
donf@us.ibm.com
Subject: Re: [RFC][PATCH] new timeofday core subsystem (v. A3)
Date: Thu, 17 Mar 2005 20:28:49 +0000 [thread overview]
Message-ID: <20050317202848.A15653@flint.arm.linux.org.uk> (raw)
In-Reply-To: <1111088697.1930.6.camel@cube>; from albert@users.sf.net on Thu, Mar 17, 2005 at 02:44:57PM -0500
On Thu, Mar 17, 2005 at 02:44:57PM -0500, Albert Cahalan wrote:
> Does the ARM kernel provide a special page of code for
> apps to execute? If not, then ARM is irrelevant.
No. However, I was responding to your suggestion that supporting
self modifying code in the kernel is trivial.
> Doesn't ARM always have an MMU? If you have an MMU, then
> it is no problem to have one single page of non-XIP code
> for this purpose.
No. You also have a big misconception about how we map system memory.
We have 1MB mappings, and replacing 1MB of code/data (which would
equate to half a kernel) would completely negate the whole point of
XIP.
> Supposing that you do support the vsyscall hack and you don't
> have an MMU, you can just place the tiny code fragment on the
> stack (or anywhere else) when an exec is performed.
>
> So, as far as I can see, ARM is fully capable of supporting this.
<cough>
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core
next prev parent reply other threads:[~2005-03-17 20:29 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-12 1:24 [RFC][PATCH] new timeofday core subsystem (v. A3) john stultz
2005-03-12 1:25 ` [RFC][PATCH] new timeofday arch specific hooks " john stultz
2005-03-12 1:26 ` [RFC][PATCH] new timeofday arch specific timesource drivers " john stultz
2005-03-12 5:52 ` [RFC][PATCH] new timeofday arch specific hooks " Benjamin Herrenschmidt
2005-03-14 18:09 ` john stultz
2005-03-15 22:59 ` Pavel Machek
2005-03-15 23:42 ` john stultz
2005-03-15 23:44 ` Pavel Machek
2005-03-16 1:44 ` john stultz
2005-03-16 10:53 ` Pavel Machek
2005-03-13 0:49 ` [RFC][PATCH] new timeofday core subsystem " Matt Mackall
2005-03-13 1:46 ` Andreas Schwab
2005-03-14 18:42 ` john stultz
2005-03-14 19:29 ` Matt Mackall
2005-03-14 19:43 ` john stultz
2005-03-14 19:51 ` Matt Mackall
2005-03-14 20:04 ` john stultz
2005-03-14 20:27 ` Matt Mackall
2005-03-15 0:01 ` Christoph Lameter
2005-03-15 2:16 ` Albert Cahalan
2005-03-15 3:22 ` Christoph Lameter
2005-03-15 15:23 ` Albert Cahalan
2005-03-15 15:52 ` Chris Friesen
2005-03-17 16:55 ` Russell King
2005-03-17 19:44 ` Albert Cahalan
2005-03-17 20:28 ` Russell King [this message]
2005-03-15 0:28 ` Christoph Lameter
2005-03-15 0:43 ` john stultz
2005-03-14 23:40 ` George Anzinger
2005-03-15 1:11 ` [topic change] jiffies as a time value john stultz
2005-03-15 23:01 ` George Anzinger
2005-03-16 3:57 ` john stultz
2005-03-15 0:07 ` [RFC][PATCH] new timeofday core subsystem (v. A3) Christoph Lameter
2005-03-15 5:37 ` Christoph Lameter
2005-03-15 18:25 ` john stultz
2005-03-15 22:08 ` George Anzinger
2005-03-17 8:15 ` Ulrich Windl
2005-03-15 6:09 ` Christoph Lameter
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