From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Thu, 06 May 2004 00:19:37 +0000 Subject: Re: 2.6.5 unwind problem with rp <- r0 Message-Id: <16537.33945.102180.589912@napali.hpl.hp.com> List-Id: References: <4885.1083211711@kao2.melbourne.sgi.com> In-Reply-To: <4885.1083211711@kao2.melbourne.sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org >>>>> On Thu, 06 May 2004 10:08:21 +1000, Keith Owens said: Keith> I would rather keep the ability to .save rp,r0 and fix the Keith> unwinder to cope, even if it needs a kludge. After all, a Keith> great luminary said that .save rp,r0 was the correct fix back Keith> in March 2003. Keith> http://marc.theaimsgroup.com/?l=linux-ia64&m5590709806090&w=2 I'd have preferred if there had been a simple and clean fix to the existing unwinder that supports .save rp,r0, but I haven't seen/found something acceptable yet. Also, the kernel has always been using the non-race-free version for historical reasons. In other words: when the new unwinder goes in, we need to go through the code and replace ".save rp, r4; mov r4=r0" with ".save rp, r0" anyhow. start_kernel_thread() is special because we can tweak it easily enough to make the ".save rp, r4" work in a race-free manner. --david