From patchwork Wed Apr 27 22:16:09 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Pitre X-Patchwork-Id: 1204 Return-Path: Delivered-To: unknown Received: from imap.gmail.com (74.125.159.109) by localhost6.localdomain6 with IMAP4-SSL; 08 Jun 2011 14:50:08 -0000 Delivered-To: patches@linaro.org Received: by 10.224.2.73 with SMTP id 9cs124918qai; Wed, 27 Apr 2011 15:16:14 -0700 (PDT) Received: by 10.229.37.2 with SMTP id v2mr2218169qcd.197.1303942573762; Wed, 27 Apr 2011 15:16:13 -0700 (PDT) Received: from mail-vx0-f178.google.com ([209.85.220.178]) by mx.google.com with ESMTPS id j23si3269002qck.50.2011.04.27.15.16.12 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 27 Apr 2011 15:16:12 -0700 (PDT) Received-SPF: neutral (google.com: 209.85.220.178 is neither permitted nor denied by best guess record for domain of nicolas.pitre@linaro.org) client-ip=209.85.220.178; Authentication-Results: mx.google.com; spf=neutral (google.com: 209.85.220.178 is neither permitted nor denied by best guess record for domain of nicolas.pitre@linaro.org) smtp.mail=nicolas.pitre@linaro.org Received: by vxc11 with SMTP id 11so2035796vxc.37 for ; Wed, 27 Apr 2011 15:16:12 -0700 (PDT) Received: by 10.52.172.2 with SMTP id ay2mr619365vdc.50.1303942571864; Wed, 27 Apr 2011 15:16:11 -0700 (PDT) Received: from xanadu.home (modemcable092.28-130-66.mc.videotron.ca [66.130.28.92]) by mx.google.com with ESMTPS id 15sm275382vdh.27.2011.04.27.15.16.09 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 27 Apr 2011 15:16:10 -0700 (PDT) Date: Wed, 27 Apr 2011 18:16:09 -0400 (EDT) From: Nicolas Pitre X-X-Sender: nico@xanadu.home To: Tony Lindgren cc: Shawn Guo , linux-arm-kernel@lists.infradead.org, patches@linaro.org, Aaro Koskinen , linux-omap@vger.kernel.org Subject: Re: [PATCH] ARM: Fix relocation if image end past uncompressed kernel end In-Reply-To: <20110427125631.GF3755@atomide.com> Message-ID: References: <1303272904-31392-1-git-send-email-nicolas.pitre@linaro.org> <20110420072156.GA28679@atomide.com> <20110420165514.GE10402@atomide.com> <20110421055945.GB13688@atomide.com> <20110421104954.GH13688@atomide.com> <20110427124726.GE3755@atomide.com> <20110427125631.GF3755@atomide.com> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 On Wed, 27 Apr 2011, Tony Lindgren wrote: > * Tony Lindgren [110427 05:44]: > > We can't overwrite the running code when relocating only a small amount, > > say 0x100 or so. > > > > There's no need to relocate all the way past the compressed kernel, > > we just need to relocate past the size of the code in head.o. > > > > Updated patch below using the GOT end instead of the compressed > > image end. > > Oops, the mov should be movle of course. Updated patch below. This is wrong. You're using r12 before it is fixed up with the proper offset. And this could simply be fixed with a big enough constant like this: diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index 8dab5e3..71fc1d9 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -250,8 +250,11 @@ restart: adr r0, LC0 * Because we always copy ahead, we need to do it from the end and go * backward in case the source and destination overlap. */ - /* Round up to next 256-byte boundary. */ - add r10, r10, #256 + /* + * Round to a 256-byte boundary on the next page. This + * avoids overwriting ourself if the offset is small. + */ + add r10, r10, #4096 bic r10, r10, #255 sub r9, r6, r5 @ size to copy