On Wed, Oct 31, 2018 at 02:19:07PM +0100, Jiri Kosina wrote: > On Wed, 31 Oct 2018, Mark Rutland wrote: > > > I guess skipping the original function prologue would simplify the > > implementation of the replacement function (and would mean that the regs > > held the function arguments per the procedure call standard), but AFAICT > > other architectures aren't relying on that, so it doesn't seem to be a > > strict requirement. > > > > What am I missing? > > > > How does livepatching handle the pre-mcount function preambles on > > architectures with existing support? > > 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. Thanks for correcting me, and sorry for noise! Mark.
