Re: [PATCH v1 1/1] ArmPkg/ArmGicDxe: fix writes to GICD_IPRIORITYR<n> when ARE enable

["Quan Nguyen" <quan@os.amperecomputing.com>]

Dear all,
Any comments about this patch ?

Without this patch there are errors recorded in GICT_ERR<n>STATUS as below:
(https://developer.arm.com/documentation/100336/0002/programmers-model/gict-register-summary/error-record-primary-status-register--gict-err-n-status?lang=en)

+ GICT_ERR<n>STATUS = 0x000000006C20030F
That means:
      V = 1: Status register is valid
      UE = 1: Un-correctable Error
      OF = 1: overflow
      MV =1 Misc0 and Misc1 are valid
      IERR = 0x3 & SERR=0xF: SYN_GICR_ARE = Attempt to access GICR or GICD registers in mode that cannot work.

+ GICT_ERR<n>MISC0 = 0x0000000000000000
     ie: Mis0[8:0] = 0: core ID 0

+ GICT_ERR<n>MISC1 = 0x0000000000000000

Thanks,
Quan 

On 10/28/20, 08:22, "Quan Nguyen OS" <quan@os.amperecomputing.com> wrote:

    According to ARM doc IHI 0069F, section 11.9.18, "Accessing the
    GICD_IPRIORITYR<n>:", "These registers are always used when affinity
    routing is not enabled. When affinity routing is enabled for the
    Security state of an interrupt:
     * GICR_IPRIORITYR<n> is used instead of GICD_IPRIORITYR<n> where n = 0
    to 7 (that is, for SGIs and PPIs)."

    The current ArmGicV3 code tries to initialize all the IPRIORITYR
    registers to a default state via the Distributor (GICD), so skip
    writes to the first eight IPRIORITYR registers when Affinity Routing
    is Enabled.

    Cc: Leif Lindholm <leif@nuviainc.com>
    Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
    Signed-off-by: Victor Gallardo <Victor@os.amperecomputing.com>
    Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
    ---
     ArmPkg/Drivers/ArmGic/GicV3/ArmGicV3Dxe.c | 11 +++++++++++
     1 file changed, 11 insertions(+)

    diff --git a/ArmPkg/Drivers/ArmGic/GicV3/ArmGicV3Dxe.c b/ArmPkg/Drivers/ArmGic/GicV3/ArmGicV3Dxe.c
    index d7da1f198d9e..bc543502481b 100644
    --- a/ArmPkg/Drivers/ArmGic/GicV3/ArmGicV3Dxe.c
    +++ b/ArmPkg/Drivers/ArmGic/GicV3/ArmGicV3Dxe.c
    @@ -378,6 +378,7 @@ GicV3DxeInitialize (
       UINTN                   RegShift;

       UINT64                  CpuTarget;

       UINT64                  MpId;

    +  BOOLEAN                 AffinityRoutingEnabled = FALSE;



       // Make sure the Interrupt Controller Protocol is not already installed in

       // the system.

    @@ -391,11 +392,21 @@ GicV3DxeInitialize (
       // Routing enabled. So ensure that the ARE bit is set.

       if (!FeaturePcdGet (PcdArmGicV3WithV2Legacy)) {

         MmioOr32 (mGicDistributorBase + ARM_GIC_ICDDCR, ARM_GIC_ICDDCR_ARE);

    +    // If Affinity Routing is Enabled, the first 32 interrupts (SGI and PPI)

    +    // can be programmed only through Redistributor interface (GICR).

    +    // Initializing the GICD_IPRIORITYR registers for these interrupts can be

    +    // skipped as the Redistributor will be powered up and initialized

    +    // at the appropriate time (e.g. in EL3 by trusted firmware).

    +    AffinityRoutingEnabled = TRUE;

       }



       for (Index = 0; Index < mGicNumInterrupts; Index++) {

         GicV3DisableInterruptSource (&gHardwareInterruptV3Protocol, Index);



    +    if (AffinityRoutingEnabled && Index < 32) {

    +      continue;

    +    }

    +

         // Set Priority

         RegOffset = Index / 4;

         RegShift = (Index % 4) * 8;

    -- 
    2.28.0