[U-Boot] [PATCH v1 1/5] ARM: PSCI: initialize stack pointer on secondary CPUs

[Stefano Babic]

On 03/07/2018 14:32, Stefan Agner wrote:
> Hi Tom, Hi Stefano,
> 
> On 02.07.2018 11:08, Patrick DELAUNAY wrote:
>> Hi Stefan
>>
>>> From: Stefan Agner [mailto:stefan at agner.ch]
>>> Sent: mercredi 27 juin 2018 10:36
>>> Subject: Re: [PATCH v1 1/5] ARM: PSCI: initialize stack pointer on secondary CPUs
>>>
>>> On 24.06.2018 21:09, Stefan Agner wrote:
>>>> From: Stefan Agner <stefan.agner at toradex.com>
>>>>
>>>> A proper stack is required to safely use C code in psci_arch_cpu_entry.
>>>
>>> Patrick, I prefer to have your ack on this since you introduced
>>> psci_arch_cpu_entry.
>>>
>>> As far as I can tell STM32MP1 uses C code in psci_arch_cpu_entry. The same
>>> function in i.MX 7's PSCI implementation the compiler actually pushed stuff on
>>> the (uninitialized) stack, which caused the newly brought up CPU to immediately
>>> crash.
>>>
>>> Not sure if in your case the stack pointer is already setup by some other means
>>> or your compiler does not use the stack.
>>>
>>> In any case, I think it is better to just setup the stack properly as done in this
>>> patch...
>>
>> I expected that the secure stack is initialized by bootROM, but after
>> check on 2018.07-rc2,
>> I got a crash also with the stm32mp1 platform.
>>
>> After code review, my behavior  is clearly not safe: I don't sure that
>> the initial BootROM stack
>> is not overlapping the installed PSCI monitor code or data.
>> So I agree:  it is needed to initialize the stack in psci_cpu_entry.
>>
>> Moreover after your patch the crash is solved for my platform stm32mp1.
> 
> Given that this fixes two platforms I guess it definitely should go into
> v2018.07.
> 
> Technically, for i.MX 7 only patch 1, 2 and 3 are necessary, but 4 and 5
> are fairly straight forward and seem to work fine here.
> 
> Patch 1 is generic, so not sure through which trees the patchset should
> go...


Sorry for late answer, but benner late as never...;-)

I have applied the whole patchset to u-boot-imx. I will push it in a
couple of hours on the server.

Regards,
Stefano

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