ERRATA_751472 was Re: [PATCHv2] arm:socfpga: Enable SMP for socfpga

Pavel Machek pavel at
Sat Oct 27 07:43:56 EDT 2012


> > > multi_v7 works fine for me. But I need
> > 
> > Why? I don't think those should break other versions of A9. If they do,
> > we need to fix that. In general, we should turn on all errata for
> > multi-platform builds, so we need to make sure they are done in a
> > compatible way and can be bypassed if they have performance impacts.
> > That may ultimately require some runtime patching though.
> Our virtual platform is having a problem with CONFIG_ARM_ERRATA_751472.
> It could be that our virtual platform is not simulating this
> correctly.


#if defined(CONFIG_ARM_ERRATA_751472) && defined(CONFIG_SMP)
        ALT_SMP(cmp r6, #0x30)                  @ present prior to r3p0
	mrclt   p15, 0, r10, c15, c0, 1         @ read diagnostic register
        orrlt   r10, r10, #1 << 11              @ set bit #11
        mcrlt   p15, 0, r10, c15, c0, 1         @ write diagnostic register

Is ALT_SMP()/ALT_UP available this early during boot?

If it is, do we need the && defined(CONFIG_SMP)? ALT_UP_... should do
the right thing. (Okk, I guess the ifdef saves cca 16 bytes in the

(cesky, pictures)

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