From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Gerlach Subject: Re: [PATCH v2] misc: sram-exec: Use aligned fncpy instead of memcpy Date: Thu, 18 May 2017 10:09:41 -0500 Message-ID: References: <20170410145247.6023-1-d-gerlach@ti.com> <20170518150134.GA3142@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170518150134.GA3142@kroah.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Greg Kroah-Hartman Cc: Russell King , Arnd Bergmann , Tony Lindgren , Keerthy J , linux-kernel@vger.kernel.org, Alexandre Belloni , linux-omap@vger.kernel.org, Shawn Guo , linux-arm-kernel@lists.infradead.org List-Id: linux-omap@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 >