From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Mosberger <davidm@napali.hpl.hp.com>
Date: Tue, 11 May 2004 07:03:55 +0000
Subject: Re: 2.6.5 unwind problem with rp <- r0
Message-Id: <16544.31451.856507.322800@napali.hpl.hp.com>
List-Id: <linux-ia64.vger.kernel.org>
References: <4885.1083211711@kao2.melbourne.sgi.com>
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To: linux-ia64@vger.kernel.org

>>>>> On Fri, 07 May 2004 18:12:49 +1000, Keith Owens <kaos@sgi.com> said:

  Keith> On Wed, 5 May 2004 20:42:24 -0700, David Mosberger
  Keith> <davidm@napali.hpl.hp.com> wrote:

  >> I considered that approach but rejected it because it runs the
  >> "FORTRAN constant" risk.  That is, someone might write to a saved
  >> register (e.g., via unw_set_br()) and end up inadvertently
  >> redefining the 0 "constant" (unw_r0) to a non-zero value.

  >> Perhaps what we could do is change unw_access_{gr,br,fr,ar,pr} to
  >> reject attempts to write to the special save-address &unw_r0.  I
  >> think that would make it safe.

  Keith> Unlikely, but if that is what it takes ....

Can you try what's in the current bk repository?  It closely follows
your patch, apart from some naming and from switching the asm files to
actually use ".save rp, r0".

Thanks,

	--david