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

[Tom Rini]

On Tue, Jul 03, 2018 at 02:32:28PM +0200, 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...

I'm OK with the series coming in if Stefano is.

-- 
Tom
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