From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 7C6BD1007E4 for ; Tue, 26 Jan 2010 03:55:47 +1100 (EST) Subject: Re: [PATCH] powerpc/85xx: Fix SMP when "cpu-release-addr" is in lowmem Mime-Version: 1.0 (Apple Message framework v1077) Content-Type: text/plain; charset=us-ascii From: Kumar Gala In-Reply-To: <1261176637-23912-1-git-send-email-ptyser@xes-inc.com> Date: Mon, 25 Jan 2010 10:55:41 -0600 Message-Id: References: <1261176637-23912-1-git-send-email-ptyser@xes-inc.com> To: Peter Tyser Cc: linuxppc-dev@ozlabs.org, Nate Case List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Dec 18, 2009, at 4:50 PM, Peter Tyser wrote: > Recent U-Boot commit 5ccd29c3679b3669b0bde5c501c1aa0f325a7acb caused > the "cpu-release-addr" device tree property to contain the physical RAM > location that secondary cores were spinning at. Previously, the > "cpu-release-addr" property contained a value referencing the boot page > translation address range of 0xfffffxxx, which then indirectly accessed > RAM. > > The "cpu-release-addr" is currently ioremapped and the secondary cores > kicked. However, due to the recent change in "cpu-release-addr", it > sometimes points to a memory location in low memory that cannot be > ioremapped. For example on a P2020-based board with 512MB of RAM the > following error occurs on bootup: > > <...> > mpic: requesting IPIs ... > __ioremap(): phys addr 0x1ffff000 is RAM lr c05df9a0 > Unable to handle kernel paging request for data at address 0x00000014 > Faulting instruction address: 0xc05df9b0 > Oops: Kernel access of bad area, sig: 11 [#1] > SMP NR_CPUS=2 P2020 RDB > Modules linked in: > <... eventual kernel panic> > > Adding logic to conditionally ioremap or access memory directly resolves > the issue. > > Signed-off-by: Peter Tyser > Signed-off-by: Nate Case > Reported-by: Dipen Dudhat > Tested-by: Dipen Dudhat > --- > arch/powerpc/platforms/85xx/smp.c | 21 +++++++++++++++++++-- > 1 files changed, 19 insertions(+), 2 deletions(-) applied to merge for 2.6.33 - k