Torsten Duwe [off-list ref] writes:

As I mentioned earlier this year, it's a bad idea to call _mcount from
MMU helper functions (e.g. hash_page...), when the profiling/tracing/
live-patching/whatever framewok might in turn cause another such fault.
Jikos suggested to use fine-grained control of these functions with the
"notrace" keyword in the Linux kernel. It is mapped to GCC's (4.8, FWIW)
__attribute__((no_instrument_function)), which, to my surprise, works
for -p and -pg nicely, but does not affect -mprofile-kernel at all!

IIRC from when I was working on GCOV support in OPAL firmware (skiboot),
this doesn't affect the code generated by -fprofile-arcs, so may not
completely do what you want.