Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756568AbaD2I6O (ORCPT ); Tue, 29 Apr 2014 04:58:14 -0400 Received: from fw-tnat.austin.arm.com ([217.140.110.23]:27544 "EHLO collaborate-mta1.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751818AbaD2I6L (ORCPT ); Tue, 29 Apr 2014 04:58:11 -0400 Date: Tue, 29 Apr 2014 09:57:31 +0100 From: Catalin Marinas To: Rob Herring Cc: Marc Zyngier , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Will Deacon , "msalter@redhat.com" , Arnd Bergmann Subject: Re: [PATCH] arm64: fixmap: fix missing sub-page offset for earlyprintk Message-ID: <20140429085730.GB17007@arm.com> References: <1398711006-14943-1-git-send-email-marc.zyngier@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 29, 2014 at 12:51:18AM +0100, Rob Herring wrote: > On Mon, Apr 28, 2014 at 1:50 PM, Marc Zyngier wrote: > > Commit d57c33c5daa4 (add generic fixmap.h) added (among other > > similar things) set_fixmap_io to deal with early ioremap of devices. > > > > More recently, commit bf4b558eba92 (arm64: add early_ioremap support) > > converted the arm64 earlyprintk to use set_fixmap_io. A side effect of > > this conversion is that my virtual machines have stopped booting when > > I pass "earlyprintk=uart8250-8bit,0x3f8" to the guest kernel. > > > > Turns out that the new earlyprintk code doesn't care at all about > > sub-page offsets, and just assumes that the earlyprintk device will > > be page-aligned. Obviously, that doesn't play well with the above example. > > > > Further investigation shows that set_fixmap_io uses __set_fixmap instead > > of __set_fixmap_offset. A fix is to introduce a set_fixmap_offset_io that > > uses the latter, and to remove the superflous call to fix_to_virt > > (which only returns the value that set_fixmap_io has already given us). > > > > With this applied, my VMs are back in business. Tested on a Cortex-A57 > > platform with kvmtool as platform emulation. > > > > Cc: Mark Salter > > Cc: Catalin Marinas > > Cc: Will Deacon > > Signed-off-by: Marc Zyngier > > --- > > arch/arm64/kernel/early_printk.c | 6 ++---- > > include/asm-generic/fixmap.h | 3 +++ > > 2 files changed, 5 insertions(+), 4 deletions(-) > > This will be fixed already in 3.16 with my earlycon series[1] if this > is not taken for 3.15. I'd like to take this for 3.15 as it's currently broken. I just need another ack from Arnd on the generic header change. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/