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 <d-gerlach@xxxxxx> Acked-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx> Reviewed-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx> Acked-by: Tony Lindgren <tony@xxxxxxxxxxx>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
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