On Mon, 2017-04-03 at 10:54 +1000, Anton Blanchard wrote:

quoted

quoted

Good idea, I hadn't thought of embedding it all in a feature
section.  

It may not work currently because you get those ftr_alt_97 relocation
errors with the "else" parts because relative branches to other code
need to be direct and I think reachable from both places.

I thought about this a bit more. One potential issue will be
profiling - perf annotate will match the samples against the unpatched
code which could be very confusing.

Could we make all those functions a dynamic-linker style stub ?

IE, they "find" the right target function and call a helper to patch
the calling site to call directly into the right one on the first
call.

Cheers,
Ben.