Re: [patch] pae-2.4.3-A4

[Russell King <rmk@arm.linux.org.uk>]

On Sun, Mar 25, 2001 at 04:53:37PM +0200, Ingo Molnar wrote:
> one nontrivial issue was that on PAE the pgd has to be installed with
> 'present' pgd entries, due to a CPU erratum. This means that the
> pgd_present() code in mm/memory.c, while correct theoretically, doesnt
> work with PAE. An equivalent solution is to use !pgd_none(), which also
> works with the PAE workaround.

Certainly that's the way the original *_alloc routines used to work.
In fact, ARM never had need to implement the pmd_present() macros, since
they were never referenced - only the pmd_none() macros were.

However, I'm currently struggling with this change on ARM - so far after
a number of hours trying to kick something into shape, I've not managed
to even get to the stange where I get a kernel image to link, let alone
the compilation to finish.

One of my many dilemas at the moment is how to allocate the page 0 PMD
in pgd_alloc(), where we don't have a mm_struct to do the locking against.

--
Russell King (rmk@arm.linux.org.uk)                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html

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