[U-Boot] [PATCH v4 04/14] ARM: Factor out reusable psci_cpu_entry
Ian Campbell
ijc at hellion.org.uk
Sun Mar 1 10:16:52 CET 2015
On Sat, 2015-02-28 at 13:53 +0000, Marc Zyngier wrote:
> > +ENTRY(psci_cpu_entry)
> > + @ Set SMP bit
> > + mrc p15, 0, r0, c1, c0, 1 @ ACTLR
> > + orr r0, r0, #(1 << 6) @ Set SMP bit
> > + mcr p15, 0, r0, c1, c0, 1 @ ACTLR
> > + isb
> > +
> > + bl _nonsec_init
> > +
> > + adr r0, _psci_target_pc
> > + ldr r0, [r0]
> > + b _do_nonsec_entry
> > +ENDPROC(psci_cpu_entry)
>
> I'd add a *big* comment at the top of this. ACTLR is implementation
> dependent, and while sticking the SMP bit at this location is fairly
> common among ARM cores, it is by no mean a strong guarantee (this is
> not an architectural feature).
>
> I'd recommend making it override-able.
Tom R has a series which does something along those lines:
https://patchwork.ozlabs.org/patch/431587/
I suppose it ought to be used here too one way or another.
Ian.
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