Messages in this thread | | | Date | Wed, 31 Oct 2018 18:58:00 +0100 | From | Torsten Duwe <> | Subject | Re: [PATCH v4 1/3] arm64: implement ftrace with regs |
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On Wed, 31 Oct 2018 14:18:19 +0000 Mark Rutland <mark.rutland@arm.com> 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
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