Re: imx7d enable second core

[Andrey Smirnov <andrew.smirnov@gmail.com>]

On Thu, Jul 19, 2018 at 8:52 AM Giorgio Dal Molin
<giorgio.nicole@arcor.de> wrote:
>
> Hi Andrey,
>
> > On July 18, 2018 at 6:54 PM Andrey Smirnov <andrew.smirnov@gmail.com> wrote:
> >
> >
> > On Wed, Jul 18, 2018 at 12:28 AM Giorgio Dal Molin
> > <giorgio.nicole@arcor.de> wrote:
> > >
> > > Hi all,
> > >
> > > I'm currently working with the imx7d sabre board from NXP.
> > >
> > > I have now a running barebox bootloader and a booting kernel.
> > >
> > > My problem is now that, apparently, only one core is active:
> > >
> > > ...
> > > commandline: console=ttymxc0,115200n8 ip=11.0.0.4::11.0.0.2:255.0.0.0::eth0: root=/dev/mmcblk0p2 rootdelay=1
> > > Starting kernel in secure mode
> >
> > AFAIK, this means that you are booting in secure mode and secure
> > monitor code, which also implements PSCI needed for SMP to work, will
> > _not_ be installed by Barebox. One way to fix this would be to set:
> >
> >  global.bootm.secure_state=nonsecure
> >
> > before booting Linux. Doing that I get:
> >
> > # lscpu -e
> > CPU SOCKET CORE ONLINE MAXMHZ   MINMHZ
> > 0   0      0    yes    996.0000 792.0000
> > 1   0      1    yes    996.0000 792.0000
> > #
> >
> > on my SabreSD board.
> >
>
> I think I've found some inconsistencies in the SECURE / NONSECURE implementation
> in barebox.
>
> In arch/arm/include/asm/secure.h there is the definition:
>
> ...
> enum arm_security_state {
>         ARM_STATE_SECURE,
>         ARM_STATE_NONSECURE,
>         ARM_STATE_HYP,
>  };
>
> where ARM_STATE_SECURE == 0 and ARM_STATE_NONSECURE == 1;
>
> In arch/arm/cpu/psci.c we have:
>
> ...
> static int of_psci_fixup(struct device_node *root, void *unused)
> {
>         struct device_node *psci;
>         int ret;
>
>         if (bootm_arm_security_state() < ARM_STATE_NONSECURE)
>                 return 0;
>
>         psci = of_create_node(root, "/psci");
>         if (!psci)
>  ...
>
> This is a bit surprising and conterintuitive: I think the logic should
> be so that if the current mode is not secure then we want to go out, otherwise
> we want to generate the /psci {} dt block for the kernel. If this is true then
> we have an error here.

In ARM_STATE_SECURE the code will not install a security monitor
implementing PSCI, so it's presence is not signaled via DT to the
kernel in that mode.

>
> One more use of the state is in the start_linux() function, in arch/arm/lib32/armlinux.c:
>
> ...
> void start_linux(void *adr, int swap, unsigned long initrd_address,
>                  unsigned long initrd_size, void *oftree,
>                  enum arm_security_state state)
> {
>         void (*kernel)(int zero, int arch, void *params) = adr;
>         void *params = NULL;
>         int architecture;
>         int ret;
>
>         if (IS_ENABLED(CONFIG_ARM_SECURE_MONITOR) && state > ARM_STATE_NONSECURE) {
>                 ret = armv7_secure_monitor_install();
>                 if (ret)
>                         pr_err("Failed to install secure monitor\n");
>         }
> ...
>

Where do you see the code above? Here's what's in master:

https://git.pengutronix.de/cgit/barebox/tree/arch/arm/lib32/armlinux.c#n270

and it looks different form what you are quoting.

Thanks,
Andrey Smirnov

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