Yes, I am referring to the upcoming SBBR v1.1 content. We changed the reference 
to PSCI back to 1.0 because that version is what we need for the MP support, 
1.1 is also fine but not the minimal requirement.

- DW
-
-----Original Message-----
From: Grant Likely
Sent: Friday, May 18, 2018 12:47 PM
To: Dong Wei <[email protected]>
Cc: [email protected]; nd <[email protected]>; arm.ebbr-discuss 
<[email protected]>
Subject: Re: [Arm.ebbr-discuss] [PATCH] Add chapter for privileged/secure 
firmware

Hi Dong,

Thanks for the comments. Replies below...

On 18/05/2018 19:01, Dong Wei wrote:
> This part has been changed in the SBBR spec as we do expect server SoC to 
> support EL3 so we removed the non-PSCI mechanism. Also the PSCI Spec 
> reference is 1.0:

Can you double check that please? The copy on developer.arm.com is issue C 
(psci 1.0), but there is a more recent copy on infocenter; issue D for PSCI 1.1.

>
> UEFI is defined as a uniprocessor specification that only uses a single CPU 
> core for booting.
> Platforms providing EL3 must implement the Power State Coordination Interface 
> (PSCI) [5]. This interface will be as the main method to boot secondary 
> cores, implementing CPU idling, and providing reset and shutdown runtime 
> services.
>
> ... some ACPI related requirements...
>
> All secondary cores remain powered down during boot. After boot, OSPM can 
> call CPU_ON() into the PSCI firmware to power up a chosen core. The PSCI 
> firmware powers up, initializes the core, and starts execution at the 
> provided address.

That helps. Perhaps I'll drop the MP Boot language entirely and leave it at 
PSCI as the preferred, but Linux spin tables as a fallback, and only for DT 
systems.

g.

>
> - DW
> -
> -----Original Message-----
> From: [email protected]
> <[email protected]> On Behalf Of Grant Likely
> Sent: Friday, May 18, 2018 6:06 AM
> Cc: [email protected]; nd <[email protected]>;
> arm.ebbr-discuss <[email protected]>
> Subject: [Arm.ebbr-discuss] [PATCH] Add chapter for privileged/secure
> firmware
>
> Document the requirements for secure firmware to implement PSCI, particularly 
> in regard to multiprocessor CPU startup protocol. PSCI is by far the 
> preferred solution, but make allowance for the other existing methods.
>
> Signed-off-by: Grant Likely <[email protected]>
> ---
>   source/ebbr.rst | 25 +++++++++++++++++++++++++
>   1 file changed, 25 insertions(+)
>
> diff --git a/source/ebbr.rst b/source/ebbr.rst index 700feba..59af3c9
> 100644
> --- a/source/ebbr.rst
> +++ b/source/ebbr.rst
> @@ -309,6 +309,25 @@ the aid of the Operating System.
>   .. note:: This normally requires dedicated storage for UEFI variables that 
> is
>      not directly accessible from the Operating System.
>
> +******************************
> +Priviledged or Secure Firmware
> +******************************
> +
> +Multiprocessor Startup Protocol
> +===============================
> +Firmware resident in Trustzone EL3 must implement and conform to the
> +Power State Coordination Interface specification[PSCI_].
> +
> +Platforms without EL3 must implement one of:
> +
> +- PSCI at EL2 (leaving only EL1 available to an operating system)
> +- MP Startup for Arm[MPSTART_] (ACPI Parking Protocol) on an ACPI
> +platform
> +- Linux AArch64 spin tables[LINUXA64BOOT_] on a Devicetree platform
> +
> +However, the MP Startup and Spintable protocols are strongly discouraged.
> +Future versions of this specification will only allow PSCI, and PSCI
> +should be implemented in all new designs.
> +
>   ****************************************
>   APPENDIX A - Required UEFI Boot Services
>   ****************************************
> @@ -542,6 +561,12 @@ EFI_ISCSI_INITIATOR_NAME_PROTOCOL          16.2
>   .. [DTSPEC] `Devicetree specification v0.2
>      
> <https://github.com/devicetree-org/devicetree-specification/releases/tag/v0.2>`_,
>      `Devicetree.org <https://devicetree.org>`_
> +.. [LINUXA64BOOT] `Linux Documentation/arm64/booting.txt
> +   
> <https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/tree/Documentation/arm64/booting.txt>`_,
> +   Linux kernel
> +.. [MPSTART] `MP Startup for Arm
> +   
> <https://acpica.org/sites/acpica/files/MP%20Startup%20for%20ARM%20platforms.doc>`_,
> +   20 December 2012, `Microsoft <http://microsoft.com>`_
>   .. [PSCI] `Power State Coordination Interface Issue D (PSCI v1.1)
>      
> <http://infocenter.arm.com/help//topic/com.arm.doc.den0022d/Power_State_Coordination_Interface_PDD_v1_1_DEN0022D.pdf>`_,
>      21 April 2017, `Arm Limited <http://arm.com>`_
> --
> 2.13.0
>
> _______________________________________________
> Arm.ebbr-discuss mailing list
> [email protected]
>

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