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Date:   Tue, 26 Aug 2014 14:11:29 +0200
From:   Ralf Baechle <ralf@linux-mips.org>
To:     Joshua Kinard <kumba@gentoo.org>
Cc:     linux-mips@linux-mips.org
Subject: Re: 16k or 64k PAGE_SIZE and "illegal instruction" (signal -4) errors
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On Tue, Aug 26, 2014 at 08:03:28AM -0400, Joshua Kinard wrote:

> Yeah, coherency shouldn't be a problem for the Octane.  hardware-coherent
> like IP27.
> 
> The icache snooping fix is already enabled in
> arch/mips/include/asm/mach-ip30/cpu-feature-overrides.h:
> 
> #define cpu_icache_snoops_remote_store 1
> 
> SMP is not working yet on IP30, though.  I gave up on that for now, because
> I can't get the second CPU to start ticking properly.

Are you running a preemptible kernel?

You could also change the definition of cpu_icache_snoops_remote_store to 0
for testing.  That should make things just a bit slower but otherwise have
not impact.  Would be interesting to see if that makes the SIGs go away.

  Ralf