Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751737AbaLERxG (ORCPT ); Fri, 5 Dec 2014 12:53:06 -0500 Received: from mail-la0-f48.google.com ([209.85.215.48]:60504 "EHLO mail-la0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751081AbaLERxD (ORCPT ); Fri, 5 Dec 2014 12:53:03 -0500 MIME-Version: 1.0 In-Reply-To: <20141205172701.GW11285@n2100.arm.linux.org.uk> References: <35FD53F367049845BC99AC72306C23D103D6DB491609@CNBJMBX05.corpusers.net> <20140915113325.GD12361@n2100.arm.linux.org.uk> <20141204120305.GC17783@e104818-lin.cambridge.arm.com> <20141205120506.GH1630@arm.com> <20141205170745.GA31222@e104818-lin.cambridge.arm.com> <20141205172701.GW11285@n2100.arm.linux.org.uk> From: Peter Maydell Date: Fri, 5 Dec 2014 17:52:41 +0000 Message-ID: Subject: Re: [RFC v2] arm:extend the reserved mrmory for initrd to be page aligned To: Russell King - ARM Linux Cc: Catalin Marinas , Peter Maydell , "Wang, Yalin" , "linux-arm-msm@vger.kernel.org" , Will Deacon , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5 December 2014 at 17:27, Russell King - ARM Linux wrote: > On Fri, Dec 05, 2014 at 05:07:45PM +0000, Catalin Marinas wrote: >> On Fri, Dec 05, 2014 at 12:05:06PM +0000, Will Deacon wrote: >> > Care to submit this as a proper patch? We should at least fix Peter's issue >> > before doing things like extending headers, which won't work for older >> > kernels anyway. >> >> Quick fix is the revert of the whole patch, together with removing >> PAGE_ALIGN(end) in poison_init_mem() on arm32. If Russell is ok with >> this patch, we can take it via the arm64 tree, otherwise I'll send you a >> partial revert only for the arm64 part. > > Not really. Let's look at the history. > > For years, we've been poisoning memory, page aligning the end pointer. > This has never been an issue. Depends what you mean by "never been an issue". I had to change QEMU (commit 98ed805c, January 2013) for 32-bit ARM back when the kernel started trashing the tail end of the page after the initrd with the poisoning, to 4K-align the dtb so it didn't share a page with the initrd-tail. That nobody else complained suggests that most bootloaders don't in practice overlap the two, though (ie that QEMU is an outlier in how it chooses to arrange things in memory). I should probably have reported the breakage at the time, but I took the pragmatic (lazy?) approach of just changing our bootloader code. thanks -- PMM -- 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/