| Date | Thu, 25 Feb 2016 15:25:54 +0100 | From | Torsten Duwe <> | Subject | Re: [PATCH 08/12] powerpc/ftrace: Rework ftrace_caller() |
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On Thu, Feb 25, 2016 at 01:28:31AM +1100, Michael Ellerman wrote: > The main change is to just use paca->kernel_toc, rather than a branch to > +4 and mflr etc. That makes the code simpler and should also perform > better.
Indeed.
> There was also a sequence after ftrace_call() where we load from > pt_regs->nip, move to LR, then a few instructions later load from LRSAVE > and move to LR. Instead I think we want to put pt_regs->nip into CTR and > branch to it later.
Yes, I did some of this cleanup in the livepatch implementation.
> We also rework some of the SPR loads to hopefully speed them up a bit. > Also comment the asm much more, to hopefully make it clearer. > > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Torsten Duwe <duwe@suse.de>
Torsten
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