Re: imx7d enable second core

[Giorgio Dal Molin <giorgio.nicole@arcor.de>]

Hi Andrey,

> On July 19, 2018 at 6:09 PM Andrey Smirnov <andrew.smirnov@gmail.com> wrote:
> 
> 
> 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.
> 

you are right, I accidentally copied my 'fixed' version.

giorgio

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