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From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Anton Blanchard <anton@samba.org>
Cc: Ian Molton <spyro@f2s.com>,
	akpm@osdl.org, nickpiggin@yahoo.com.au,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Use MM_VM_SIZE in exit_mmap
Date: Tue, 25 Jan 2005 23:39:49 +0000	[thread overview]
Message-ID: <20050125233949.C30094@flint.arm.linux.org.uk> (raw)
In-Reply-To: <41F6CFF2.7010907@f2s.com>; from spyro@f2s.com on Tue, Jan 25, 2005 at 11:02:10PM +0000

On Tue, Jan 25, 2005 at 11:02:10PM +0000, Ian Molton wrote:
> Anton Blanchard wrote:
> 
>  > As an aside, all architectures except one define FIRST_USER_PGD_NR as 0:
>  >
>  > include/asm-arm26/pgtable.h:#define FIRST_USER_PGD_NR       1

I don't think Anton can count.  (and for some reason I seem to be missing
his mail at the moment.)

include/asm-arm/pgtable.h:#define FIRST_USER_PGD_NR     1

there's two.  FIRST_USER_PGD_NR was created specifically for ARM because
many of our CPUs place their hardware vector tables at *virtual* address
zero.  Unmapping this virtual page would be rather bad for the system -
consider the effect of unmapping the code for *all* CPU exceptions.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core

  reply	other threads:[~2005-01-25 23:43 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-25 14:22 [PATCH] Use MM_VM_SIZE in exit_mmap Anton Blanchard
2005-01-25 16:46 ` Chris Wedgwood
2005-01-25 16:57   ` Anton Blanchard
2005-01-25 17:13     ` Chris Wedgwood
2005-01-27 20:46     ` [PATCH RFC] Change (some) TASK_SIZE to task_vtop(current) Chris Wedgwood
2005-01-25 23:02 ` [PATCH] Use MM_VM_SIZE in exit_mmap Ian Molton
2005-01-25 23:39   ` Russell King [this message]
2005-01-26  0:01     ` Anton Blanchard
2005-01-26  0:17 ` Nick Piggin
2005-01-26  6:44 ` Andi Kleen
2005-01-26  7:39   ` William Lee Irwin III

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