From: David Mosberger <davidm@napali.hpl.hp.com>
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Message-ID: <16480.55450.730214.175997@napali.hpl.hp.com>
Date: Tue, 23 Mar 2004 16:38:50 -0800
To: Kurt Garloff <garloff@suse.de>
Cc: Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org,
       mingo@redhat.com
Subject: Re: Non-Exec stack patches
In-Reply-To: <20040324002149.GT4677@tpkurt.garloff.de>
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	<20040323154937.1f0dc500.akpm@osdl.org>
	<20040324002149.GT4677@tpkurt.garloff.de>
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>>>>> On Wed, 24 Mar 2004 01:21:49 +0100, Kurt Garloff <garloff@suse.de> said:

  >> Which architectures are currently making their pre-page execute
  >> permissions depend upon VM_EXEC?  Would additional arch patches
  >> be needed for this?

  Kurt> It works on AMD64 (not ia32e), both for 64bit and 32bit
  Kurt> binaries.  I have not yet tested other archs.

IA64 Linux had non-executable stack/data before PT_GNU_STACK was invented.
It's keyed off a ELF header flags bit:

/* Least-significant four bits of ELF header's e_flags are
   OS-specific.  The bits are interpreted as follows by Linux: */
#define EF_IA_64_LINUX_EXECUTABLE_STACK 0x1

I guess I never quiet understood why an entire program header is
needed for this, but that's just me.

	--david
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