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Date: Sun, 04 Nov 2007 22:19:20 +0100
From: Jan Kiszka <jan.kiszka@domain.hid>
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Subject: Re: [Xenomai-core] [Xenomai-commits] r3147 - __xn_access_ok changes
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To: Philippe Gerum <rpm@xenomai.org>
Cc: xenomai@xenomai.org

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[Let's discuss this without bothering users :)]

Philippe Gerum wrote:
> Author: rpm
> Date: Sun Nov  4 18:18:39 2007
> New Revision: 3147
>=20
> URL: http://svn.gna.org/viewcvs/xenomai?rev=3D3147&view=3Drev
> Log:
> Make __xn_access_ok() return false for addresses lower than the natural=
 page size.
>=20
> Modified:
>     trunk/ChangeLog
>     trunk/include/asm-x86/syscall_32.h
>     trunk/include/asm-x86/syscall_64.h

Could it be that you meant "PAGE_SIZE" instead of "PAGE_OFFSET"? Because
the current version is "slightly" broken, tagging any address in user
land as invalid.

And if this test was meant to catch NULL page accesses early, is the
intention to cope with all those current i-pipe patches that do not yet
include the discussed domain switch on non-root faults? If yes, this
test would be a workaround for legacy code and should not become default
(pure overhead for later versions).

Last question: We need this for the other archs as well, don't we?

Jan


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