[U-Boot] [PATCH 1/1] efi_loader: PSCI reset and shutdown for EL1

[Sumit Garg]

On Thu, 11 Oct 2018 at 17:50, Sumit Garg <sumit.garg at linaro.org> wrote:
>
> On Thu, 11 Oct 2018 at 08:56, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> >
> > When starting an aarch64 system under QEMU it runs in EL1/EL0. So we have
> > to use HVC for PSCI calls.
> >
> > Without the patch resetting Linux started with bootefi under
> > qemu-system-aarch64 results in a crash.
> >
> > Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> > ---
> >  arch/arm/cpu/armv8/fwcall.c | 14 +++++++++-----
> >  1 file changed, 9 insertions(+), 5 deletions(-)
> >
>
> I too was facing this crash and got it fixed before I saw this patch today.
>
> Tested-by: Sumit Garg <sumit.garg at linaro.org>
>
> > diff --git a/arch/arm/cpu/armv8/fwcall.c b/arch/arm/cpu/armv8/fwcall.c
> > index 0ba3dad8cc..f1b6e60bae 100644
> > --- a/arch/arm/cpu/armv8/fwcall.c
> > +++ b/arch/arm/cpu/armv8/fwcall.c
> > @@ -78,12 +78,10 @@ void __efi_runtime smc_call(struct pt_regs *args)
> >  }
> >
> >  /*
> > - * For now, all systems we support run at least in EL2 and thus
> > - * trigger PSCI calls to EL3 using SMC. If anyone ever wants to
> > - * use PSCI on U-Boot running below a hypervisor, please detect
> > - * this and set the flag accordingly.
> > + * This flag controls if SMC or HVC is used to call PSCI services. If U-Boot has
> > + * been called by a hypervisor (e.g. QEMU), it has to be set to false.
> >   */
> > -static const __efi_runtime_data bool use_smc_for_psci = true;
> > +static __efi_runtime_data bool use_smc_for_psci = true;
> >
> >  void __noreturn __efi_runtime psci_system_reset(void)
> >  {
> > @@ -138,6 +136,12 @@ void reset_misc(void)
> >  }
> >
> >  #ifdef CONFIG_EFI_LOADER
> > +efi_status_t efi_reset_system_init(void)
> > +{
> > +       use_smc_for_psci = (current_el() >= 2);

It doesn't seems to be a generic solution as u-boot could be loaded at
EL1 with PSCI calls still implemented in EL3 (smc for PSCI) in cases
like EL2 (virt. extension) isn't implemented on platform etc. So I
would probably suggest to use device tree parsing for PSCI method to
configure this variable here.

-Sumit

> > +       return EFI_SUCCESS;
> > +}
> > +
> >  void __efi_runtime EFIAPI efi_reset_system(
> >                         enum efi_reset_type reset_type,
> >                         efi_status_t reset_status,
> > --
> > 2.19.1
> >
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