Re: [Qemu-devel] [PATCH v2 7/9] i.MX: Add i.MX6 SOC implementation.

[Jean-Christophe DUBOIS <jcd@tribudubois.net>]

Le 29/02/2016 18:58, Peter Maydell a écrit :
> On 19 February 2016 at 06:32, Jean-Christophe DUBOIS
> <jcd@tribudubois.net> wrote:
>> If I set has_el3 to false, I can boot the 4 cores without problem. With
>> has_el3 set to true (default value) I am getting the above behavior (boot OK
>> in uniprocessor mode, and misbehaving if -smp >= 2).
> I worked out why this happens -- it's because the secondary CPUs and
> the primary disagree about whether they're booting in Secure mode.
> You can either:
> (1) have the board code say "boot the primary in Secure mode":
> --- a/hw/arm/sabrelite.c
> +++ b/hw/arm/sabrelite.c
> @@ -85,6 +85,7 @@ static void sabrelite_init(MachineState *machine)
>       sabrelite_binfo.kernel_cmdline = machine->kernel_cmdline;
>       sabrelite_binfo.initrd_filename = machine->initrd_filename;
>       sabrelite_binfo.nb_cpus = smp_cpus;
> +    sabrelite_binfo.secure_boot = true;
>       sabrelite_binfo.write_secondary_boot = sabrelite_write_secondary;
>       sabrelite_binfo.secondary_cpu_reset_hook = sabrelite_reset_secondary;
>
> or (2) have the code in imx6_src.c tell the secondaries that
> they should start in non-secure mode:
>
> --- a/hw/misc/imx6_src.c
> +++ b/hw/misc/imx6_src.c
> @@ -144,6 +144,7 @@ static void imx6_src_cpu_on(uint32_t cpuid,
> uint32_t entry, uint32_t context_id)
>
>       target_cpu->env.regs[0] = context_id;
>       target_cpu->env.thumb = entry & 1;
> +    target_cpu->env.cp15.scr_el3 |= SCR_NS;
>
>       target_cpu_class->set_pc(target_cpu_state, entry);
>   }
>
> If you do either of these then the system will boot the kernel that
> you sent the link to.

Thanks Peter, It does work.

>
> To answer the question of "which of these is the correct thing to do"
> we need to look at what the real hardware does when it's running Linux:
> does it run Linux in Secure or Nonsecure?

i.MX6 is definitively able to boot in secure/trustzone mode (there are 
some demo out there about it) so I guess it might be booting in secure mode.

>
> thanks
> -- PMM
>