On Wed, 31 Oct 2018 14:18:19 +0000 Mark Rutland <mark.rutland@xxxxxxx> wrote: > On Wed, Oct 31, 2018 at 02:19:07PM +0100, Jiri Kosina wrote: > > Other architectures do rely on that. That's exactly for example why > > on x86 we use '-pg -mfentry', to make sure we hook the function > > *before* prologue. > > Ah, I'd missed -mfentry for x86. I now see that's also the case with > __gnu_mcount_nc on arch/arm, so that covers my confusion. Yes, fentry used to be the prerequisite, but it's everything but portable. PPC64 already had the profile-kernel switch, which was becoming just usable as we got at live patching. I'm hoping that the patchable-function-entry will become the future de-facto standard. Torsten
