On Fri, Apr 19, 2019 at 5:43 PM Peter Zijlstra <pet...@infradead.org> wrote: > > On Fri, Apr 19, 2019 at 10:17:49AM +0800, Kairui Song wrote: > > On Fri, Apr 19, 2019 at 8:58 AM Josh Poimboeuf <jpoim...@redhat.com> wrote: > > > > > > I still don't like using regs->bp because it results in different code > > > paths for FP and ORC. In the FP case, the regs are treated like real > > > regs even though they're fake. > > > > > > Something like the below would be much simpler. Would this work? I don't > > > know if any other code relies on the fake regs->bp or regs->sp. > > > > Works perfectly. My only concern is that FP path used to work very > > well, not sure it's a good idea to change it, and this may bring some > > extra overhead for FP path. > > Given Josh wrote all that code, I'm fairly sure it is still OK :-) > > But also looking at the code in unwind_frame.c, __unwind_start() seems > to pretty much do what the removed caller_frame_pointer() did (when > .regs=NULL) but better. >
OK, with FP we will also need to do a few more extra unwinding, previously it start directly from the frame of the trace point, now have to trace back to the trace point first. If that's fine I could post another update (that will be pretty much just copy&paste from the Josh's code he posted :P , is this OK?) -- Best Regards, Kairui Song
