Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE

[David Mosberger]

>>>>> On Tue, 25 May 2004 06:20:54 +0200, Andrea Arcangeli <andrea@xxxxxxx> said:

  Andrea> the only architecture that has the accessed bit in
  Andrea> _hardware_ via page faults I know is ia64, but I don't know
  Andrea> if it has a mode to set it without page faults

No, it doesn't.

  Andrea> and how it is implementing the accessed bit in linux.

If the "accessed" or "dirty" bits are zero, accessing/writing the
page will cause a fault which will be handled in a low-level
fault handler.  The Linux version of these handlers simply turn
on the respective bit.  See daccess_bit(), iaccess_bit(), and dirty_bit()
in arch/ia64/kernel/ivt.S.

Note: I'm on travel and haven't seen the context of this discussion
and don't expect to have time to think about this until I return on
Thursday.  So if you don't hear from me, it's not because I'm ignoring
you... ;-)

	--david
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