Messages in this thread | | | Date | Tue, 16 May 2017 09:01:27 -0700 | From | Tony Lindgren <> | Subject | Re: [PATCH v2] misc: sram-exec: Use aligned fncpy instead of memcpy |
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* Russell King - ARM Linux <linux@armlinux.org.uk> [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 <d-gerlach@ti.com> > > Looks a lot saner, thanks. It's just a bit sad that we lose the type > checking. > > Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
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
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