From: Jakub Jelinek <jakub@redhat.com>
To: Jamie Lokier <jamie@shareable.org>
Cc: "Keith M. Wesolowski" <wesolows@foobazco.org>,
sparclinux@vger.kernel.org, "David S. Miller" <davem@redhat.com>,
ultralinux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: A question about PROT_NONE on Sparc and Sparc64
Date: Wed, 30 Jun 2004 04:28:05 -0400 [thread overview]
Message-ID: <20040630082804.GS21264@devserv.devel.redhat.com> (raw)
In-Reply-To: <20040630030503.GA25149@mail.shareable.org>
On Wed, Jun 30, 2004 at 04:05:03AM +0100, Jamie Lokier wrote:
> I'm doing a survey of the different architectural implementations of
> PROT_* flags for mmap() and mprotect(). I'm looking at linux-2.6.5.
>
> The Sparc and Sparc64 implementations are very similar to plain x86:
> read implies exec, exec implies read and write implies read.
>
> (Aside: A comment in include/asm-sparc/pgtsrmmu.h says that finer-grained
> access is possible. Quite a few other architectures do implement
> finer-grained access, and even x86 is getting it now, so you may want
> to revisit that. The code is already available, and tested, if you
> cut that part out of the PaX security patch).
I believe R!X and X!R pages ought to be possible on sparc64 too, just use a
different bit as "read" in the fast ITLB miss handler from the one fast DTLB
miss uses.
Jakub
next prev parent reply other threads:[~2004-06-30 8:28 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-06-30 3:05 A question about PROT_NONE on Sparc and Sparc64 Jamie Lokier
2004-06-30 5:17 ` David S. Miller
2004-06-30 15:21 ` wesolows
2004-06-30 8:28 ` Jakub Jelinek [this message]
2004-06-30 20:54 ` David S. Miller
2004-06-30 22:52 ` Jamie Lokier
2004-07-01 5:25 ` David S. Miller
2004-07-01 7:47 ` David S. Miller
2004-07-02 1:03 ` A question about PROT_NONE on Sun4c 32-bit Sparc Jamie Lokier
2004-07-02 4:11 ` Keith M. Wesolowski
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