On Fri, Mar 04, 2016 at 07:16:57PM +0100, Torsten Duwe wrote: > On Fri, Mar 04, 2016 at 02:01:37PM +0100, Petr Mladek wrote: > > > > Do I understand it correctly that we could not patch functions that > > pass arguments on the stack with this implementation? If yes, how hard > > would be to get it working, please? At least, it would be great to > > catch this problem and handle it with grace. Otherwise, it might > > be hard to debug. > > No, those functions only require special attention. So far it's correct. It's been a while since I wrote that code. > I needed _any_ location to store the caller's TOC; > and the stack is thread-safe and recursion-safe. > The current caller's frame is already full so I had > to create a new one. Correction: the TOC can be stored in the caller's stack frame at the usual location. Only the restore instruction is a problem. > A patch function could e.g. grab that TOC value in a > prologue and then pop that stack frame. Or it could > add those 32 bytes to the assumed arguments' stack offsets. So one solution could be to call the patch function via a small trampoline or pre-prologue that just pops that frame, and have the patch function restore R2 manually at the end. Sorry for the confusion, Torsten -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
