From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@citrix.com>
Subject: Re: Arndale secondary CPU boot issue Was Re:
 [xen-unstable test] 60076: regressions - FAIL
Date: Thu, 30 Jul 2015 12:36:01 +0100
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To: Ian Campbell <ian.campbell@citrix.com>, Dario Faggioli <dario.faggioli@citrix.com>, osstest service owner <osstest-admin@xenproject.org>
Cc: xen-devel@lists.xensource.com, David Vrabel <david.vrabel@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>
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Hi Ian,

On 30/07/15 09:55, Ian Campbell wrote:
> On Wed, 2015-07-29 at 19:18 +0100, Julien Grall wrote:
>> It appears to be required on the Arndale to boot secondaries CPUs.
>> Although, depending on where I put the sev I don't have the same 
>> behavior:
>> 	- sev in smp_init callback: the CPU is not coming up
>> 	- sev before or after arch_cpu_up: the CPU is booting but not in 
>> HYP
>> mode [2]
>>
>> I haven't yet figured out where the "sev" should be placed in order to
>> get the CPU boot correctly.
> 
> Does the arndale end up using 
> .cpu_up = cpu_up_send_sgi,
> or
> .cpu_up = exynos5_cpu_up,
> ?

The first one given that the arndale is an exynos5250. I'm not sure why
we didn't use exynos5_cpu_up. Although it doesn't seem to fix the problem.

>> What I don't understand is how the placement of "sev" would affect the
>> secondary processor to boot in HYP mode or Kernel mode or nothing at all
>>
>> This platform seems very picky and I don't remember having a
>> documentation about how the SMP boot works for this platform. Linux
>> seems to avoid the SEV for this platform.
> 
> 32-bit Linux has some in common code paths IIRC, which are not always
> apparent at first glance.

Good to know.

Regards,

-- 
Julien Grall