From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751547AbdEPQBf (ORCPT ); Tue, 16 May 2017 12:01:35 -0400 Received: from muru.com ([72.249.23.125]:47806 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750777AbdEPQBb (ORCPT ); Tue, 16 May 2017 12:01:31 -0400 Date: Tue, 16 May 2017 09:01:27 -0700 From: Tony Lindgren To: Russell King - ARM Linux Cc: Dave Gerlach , Greg Kroah-Hartman , Arnd Bergmann , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, Shawn Guo , Alexandre Belloni , Keerthy J Subject: Re: [PATCH v2] misc: sram-exec: Use aligned fncpy instead of memcpy Message-ID: <20170516160127.GH31418@atomide.com> References: <20170410145247.6023-1-d-gerlach@ti.com> <20170503185533.GS23750@n2100.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170503185533.GS23750@n2100.armlinux.org.uk> User-Agent: Mutt/1.8.2 (2017-04-18) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Russell King - ARM Linux [170503 11:58]: > 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 > > Looks a lot saner, thanks. It's just a bit sad that we lose the type > checking. > > Acked-by: Russell King Looks like this is still pending so I'll add it into omap-for-v4.12/fixes so we can get this out of the way. Regards, Tony From mboxrd@z Thu Jan 1 00:00:00 1970 From: tony@atomide.com (Tony Lindgren) Date: Tue, 16 May 2017 09:01:27 -0700 Subject: [PATCH v2] misc: sram-exec: Use aligned fncpy instead of memcpy In-Reply-To: <20170503185533.GS23750@n2100.armlinux.org.uk> References: <20170410145247.6023-1-d-gerlach@ti.com> <20170503185533.GS23750@n2100.armlinux.org.uk> Message-ID: <20170516160127.GH31418@atomide.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org * Russell King - ARM Linux [170503 11:58]: > 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 > > Looks a lot saner, thanks. It's just a bit sad that we lose the type > checking. > > Acked-by: Russell King Looks like this is still pending so I'll add it into omap-for-v4.12/fixes so we can get this out of the way. Regards, Tony