From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stepan Moskovchenko Subject: Re: [PATCH] arm: Prevent memory aliasing on non-LPAE kernels Date: Fri, 31 May 2013 18:30:52 -0700 Message-ID: <51A94ECC.5090303@codeaurora.org> References: <1369950320-22784-1-git-send-email-stepanm@codeaurora.org> <3054064.aJsgTxiNUL@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.codeaurora.org ([198.145.11.231]:40911 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755954Ab3FABay (ORCPT ); Fri, 31 May 2013 21:30:54 -0400 In-Reply-To: <3054064.aJsgTxiNUL@wuerfel> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Arnd Bergmann Cc: linux-arm-kernel@lists.infradead.org, Russell King , linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, David Brown , Bryan Huntsman , Daniel Walker On 5/30/2013 3:24 PM, Arnd Bergmann wrote: >> + if (size > ((phys_addr_t)~0)) >> + size = ((phys_addr_t)~0); >> + >> + /* arm_add_memory() already checks for the case of base + size > 4GB */ >> +#endif >> arm_add_memory(base, size); >> } > > This looks wrong for the case where 'base' is between >0 and 4GB and 'size' > makes it spill over the 4GB boundary. You need to set > 'size = (phys_addr_t)~0 - base' then. > Ah. I believe arm_add_memory() already has the logic to handle this case. Here, we are just trying to shrink 'size' to fit into phys_addr_t, since it is currently u64 but arm_add_memory() uses phys_addr_t for its arguments. I did not want to have this logic in two places, but I can do what you said if you like. -- The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation