From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH v2] misc: sram-exec: Use aligned fncpy instead of memcpy Date: Wed, 26 Apr 2017 07:49:43 -0700 Message-ID: <20170426144943.GG3780@atomide.com> References: <20170410145247.6023-1-d-gerlach@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20170410145247.6023-1-d-gerlach@ti.com> Sender: linux-kernel-owner@vger.kernel.org To: Dave Gerlach Cc: Greg Kroah-Hartman , Arnd Bergmann , Russell King , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, Shawn Guo , Alexandre Belloni , Keerthy J List-Id: linux-omap@vger.kernel.org * Dave Gerlach [170410 07:55]: > 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. Looks good to me: Acked-by: Tony Lindgren