Re: [PATCH] Use MM_VM_SIZE in exit_mmap

[Russell King <rmk+lkml@xxxxxxxxxxxxxxxx>]

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
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