From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933641AbdERPMC (ORCPT ); Thu, 18 May 2017 11:12:02 -0400 Received: from fllnx209.ext.ti.com ([198.47.19.16]:49056 "EHLO fllnx209.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932227AbdERPL6 (ORCPT ); Thu, 18 May 2017 11:11:58 -0400 Subject: Re: [PATCH v2] misc: sram-exec: Use aligned fncpy instead of memcpy To: Greg Kroah-Hartman References: <20170410145247.6023-1-d-gerlach@ti.com> <20170518150134.GA3142@kroah.com> CC: Arnd Bergmann , Tony Lindgren , Russell King , , , , Shawn Guo , Alexandre Belloni , Keerthy J From: Dave Gerlach Message-ID: Date: Thu, 18 May 2017 10:09:41 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20170518150134.GA3142@kroah.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [128.247.59.203] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/18/2017 10:01 AM, Greg Kroah-Hartman wrote: > On Mon, Apr 10, 2017 at 09:52:47AM -0500, Dave Gerlach wrote: >> Currently the sram-exec functionality, which allows allocation of >> executable memory and provides an API to move code to it, is only >> selected in configs for the ARM architecture. Based on commit >> 5756e9dd0de6 ("ARM: 6640/1: Thumb-2: Symbol manipulation macros for >> function body copying") simply copying a C function pointer address >> using memcpy without consideration of alignment and Thumb is unsafe on >> ARM platforms. >> >> The aforementioned patch introduces the fncpy macro which is a safe way >> to copy executable code on ARM platforms, so let's make use of that here >> rather than the unsafe plain memcpy that was previously used by >> sram_exec_copy. Now sram_exec_copy will move the code to "dst" and >> return an address that is guaranteed to be safely callable. >> >> In the future, architectures hoping to make use of the sram-exec >> functionality must define an fncpy macro just as ARM has done to >> guarantee or check for safe copying to executable memory before allowing >> the arch to select CONFIG_SRAM_EXEC. >> >> Signed-off-by: Dave Gerlach >> Acked-by: Russell King >> Reviewed-by: Alexandre Belloni >> Acked-by: Tony Lindgren > > Can you rebase this and resend as it doesn't apply to the tree right now > :( > Resent as v3 based on v4.12-rc1 and with Acks from v2 added, thanks. Regards, Dave > thanks, > > greg k-h >