From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 5 Feb 2002 11:56:18 -0700 From: Val Henson To: benh@kernel.crashing.org Cc: linuxppc-dev@lists.linuxppc.org Subject: Re: Highmem on PPC? Message-ID: <20020205115618.D6834@boardwalk> References: <20020204183236.J3277@boardwalk> <20020205125256.16831@mailhost.mipsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20020205125256.16831@mailhost.mipsys.com>; from benh@kernel.crashing.org on Tue, Feb 05, 2002 at 01:52:56PM +0100 Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On Tue, Feb 05, 2002 at 01:52:56PM +0100, benh@kernel.crashing.org wrote: > > >What's the current state of highmem on the G4? Does it work, not > >work, kinda work, only work on UP... ? > > > >I hope to have a dual 7450 G4 with 1 GB RAM within a week, at which > >point I'll be able to work on highmem seriously. > > It's supposed to work. However, I'm having reports of dual 7450 with > 1G or 1.5G of RAM locking up, I haven't been able to track those down. > > Is this an Apple machine ? The 7450 has a bug that prevents use on > SMP with HW hash table walk. Apple is supposed to implement a HW > workaround for this on their machines, but if it's not an Apple machine, > then you may have to implement software TLB load. The dual 7450 is an apple machine. I also have one of our beta boards, a dual 7410 with 1 GB RAM, and we're planning on having a dual 7450 with 1 GB RAM just as soon as we get the chips. What's your philosophy about highmem? We map all lowmem with BATs on SMP in order to avoid trashing SRR0/SRR1 according to your new comment in entry.S, but it also mentions "other cpus" without saying which cpu you're talking about. :) How are you avoiding recursive TLB faults on the highmem pages themselves? What cpus did you have in mind when you wrote the SMP stuff? I'm currently getting hard crashes on the dual 7410 with highmem. Not even the SMI starts xmon. I'm not sure that it's a software bug, which is why I'm getting the dual 7450. -VAL ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/