Messages in this thread | | | Date | Tue, 9 Aug 2022 14:49:19 -0700 | From | Ira Weiny <> | Subject | Re: [RFC PATCH 2/5] entry: Add calls for save/restore auxiliary pt_regs |
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On Tue, Aug 09, 2022 at 08:49:47PM +0200, Borislav Petkov wrote: > On Tue, Aug 09, 2022 at 11:38:03AM -0700, Ira Weiny wrote: > > Thomas did a lot of work to make the entry code generic. So I was > > keeping that work consistent. This also helps to ensure I did not miss > > any places. > > How about you worry about the other arches when you actually cross that > bridge?
I guess I miss understood the reasoning behind Thomas' work. No one mentioned trying to isolate this to x86 during the PKS review.
> > > I don't believe this is correct because instrumentation is not enabled > > here. > > Why do you have to run > > arch_save_aux_pt_regs() > > with instrumentation enabled?
Sorry, that was carried over from the PKS series where I did need to call it.
I pulled this series over quickly to show basically what needed to be done. But I did not review it for this detail.
> > Patch 5 does > > + struct pt_regs_auxiliary *aux_pt_regs = &to_extended_pt_regs(regs)->aux; > + > + aux_pt_regs->cpu = raw_smp_processor_id(); > > only? > > Why does that need to run with instrumentation enabled?
This does not.
Am I wrong that instrumentation begin/end are 0 overhead in production builds?
Ira
> > -- > Regards/Gruss, > Boris. > > https://people.kernel.org/tglx/notes-about-netiquette
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