From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <ijc@hellion.org.uk>
Date: Sun, 01 Mar 2015 09:16:52 +0000
Subject: [U-Boot] [PATCH v4 04/14] ARM: Factor out reusable
	psci_cpu_entry
In-Reply-To: <20150228135312.0d493843@arm.com>
References: <cover.1425043693.git.jan.kiszka@siemens.com>
 <5e62f5242de46bee80f6b12999125a296443a45d.1425043693.git.jan.kiszka@siemens.com>
 <20150228135312.0d493843@arm.com>
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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.