From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jack Steiner Date: Fri, 09 May 2003 20:02:47 +0000 Subject: Re: [Linux-ia64] Re: [PATCH] head.S fix for unusual load addrs Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org > > >>>>> On Fri, 9 May 2003 10:52:25 -0700, Jesse Barnes said: > > Jesse> So, is there any consensus on the best path to pursue? Chris Wedgwood > Jesse> is working on option #3, and I've got Tony's patch trimmed down to #2 > Jesse> (with one piece missing--ia64_switch_to runtime patching), but none of > Jesse> these are in either 2.4 or 2.5 yet. Maybe for 2.4 we should do #2 or > Jesse> #3 and for 2.5 we could implement #1 with the virtual offsets Tony > Jesse> mentioned earlier? > > I'm not sure. I got the impression Tony may be looking at the virtual > remapping in region 5. I haven't heard whether text replication > turned out to be important for 8870, but I'm starting to lean towards > virtual remapping because it is more versatile (can handle both > "strange" physical memory layouts and kernel replication). This, > coupled with the fact that it doesn't break any of the existing tools > makes it pretty compelling. Also, my primary objection about making > the kernel model more complicated doesn't hold much water if we move > everything to region 5. > > Would there be a downside to this on SGI's machines? I dont see any significant problems. It actually seems easy. I think we still need to use __tpa() for addresses assigned by the loader. The standard __pa() macros wont work in region 5. I dont have any objections to __tpa. We have had them in the kernel since ~2.3.42 & have not had any problems with them. On occasion, when we upgrade, we have to add/delete a couple of references but these are always easy to find. I dont recall any changes for the last couple of upgrades but maybe we were just lucky. As I mention in mail earlier, >> The __tpa macros are ugly but they are fully contained within the ia64 part >> of the tree. (IIRC, the old scheduler had a reference but the O(1) scheduler doe not). >> In our tree, there are currently only 12 references to __tpa. All are >> in boottime initialization code, mostly in mca.c. Although I would >> rather not have __tpa, this doesnt seem too bad. > > --david > > _______________________________________________ > Linux-IA64 mailing list > Linux-IA64@linuxia64.org > http://lists.linuxia64.org/lists/listinfo/linux-ia64 > -- Thanks Jack Steiner (651-683-5302) (vnet 233-5302) steiner@sgi.com