Re: [PATCH v1 1/1] ArmPkg/OpteeLib: Add dummy RPC handler

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On Wed, 5 Dec 2018 at 12:58, Sumit Garg <sumit.garg@linaro.org> wrote:
>
> Add dummy RPC handler for RPCs that are not implemented as control
> should be returned back to OP-TEE in case any RPC is invoked.
>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Sumit Garg <sumit.garg@linaro.org>

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Pushed as bc39c5cbea30..088a5334809d

Thanks

> ---
>  ArmPkg/Library/OpteeLib/OpteeSmc.h |  3 ++
>  ArmPkg/Library/OpteeLib/Optee.c    | 34 ++++++++++++++++----
>  2 files changed, 30 insertions(+), 7 deletions(-)
>
> diff --git a/ArmPkg/Library/OpteeLib/OpteeSmc.h b/ArmPkg/Library/OpteeLib/OpteeSmc.h
> index 9cccd81810c9..6209782aaed7 100644
> --- a/ArmPkg/Library/OpteeLib/OpteeSmc.h
> +++ b/ArmPkg/Library/OpteeLib/OpteeSmc.h
> @@ -25,6 +25,9 @@
>
>  #define OPTEE_SMC_SHARED_MEMORY_CACHED          1
>
> +#define OPTEE_SMC_RETURN_UNKNOWN_FUNCTION       0xffffffff
> +#define OPTEE_SMC_RETURN_RPC_PREFIX_MASK        0xffff0000
> +#define OPTEE_SMC_RETURN_RPC_PREFIX             0xffff0000
>  #define OPTEE_SMC_RETURN_RPC_FOREIGN_INTERRUPT  0xffff0004
>
>  #define OPTEE_MESSAGE_COMMAND_OPEN_SESSION      0
> diff --git a/ArmPkg/Library/OpteeLib/Optee.c b/ArmPkg/Library/OpteeLib/Optee.c
> index 55dcc7853b59..ed2a03c593c2 100644
> --- a/ArmPkg/Library/OpteeLib/Optee.c
> +++ b/ArmPkg/Library/OpteeLib/Optee.c
> @@ -123,6 +123,17 @@ OpteeInit (
>    return EFI_SUCCESS;
>  }
>
> +STATIC
> +BOOLEAN
> +IsOpteeSmcReturnRpc (
> +  UINT32 Return
> +  )
> +{
> +  return (Return != OPTEE_SMC_RETURN_UNKNOWN_FUNCTION) &&
> +         ((Return & OPTEE_SMC_RETURN_RPC_PREFIX_MASK) ==
> +          OPTEE_SMC_RETURN_RPC_PREFIX);
> +}
> +
>  /**
>    Does Standard SMC to OP-TEE in secure world.
>
> @@ -147,13 +158,22 @@ OpteeCallWithArg (
>    while (TRUE) {
>      ArmCallSmc (&ArmSmcArgs);
>
> -    if (ArmSmcArgs.Arg0 == OPTEE_SMC_RETURN_RPC_FOREIGN_INTERRUPT) {
> -      //
> -      // A foreign interrupt was raised while secure world was
> -      // executing, since they are handled in UEFI a dummy RPC is
> -      // performed to let UEFI take the interrupt through the normal
> -      // vector.
> -      //
> +    if (IsOpteeSmcReturnRpc (ArmSmcArgs.Arg0)) {
> +      switch (ArmSmcArgs.Arg0) {
> +      case OPTEE_SMC_RETURN_RPC_FOREIGN_INTERRUPT:
> +        //
> +        // A foreign interrupt was raised while secure world was
> +        // executing, since they are handled in UEFI a dummy RPC is
> +        // performed to let UEFI take the interrupt through the normal
> +        // vector.
> +        //
> +        break;
> +
> +      default:
> +         // Do nothing in case RPC is not implemented.
> +        break;
> +      }
> +
>        ArmSmcArgs.Arg0 = OPTEE_SMC_RETURN_FROM_RPC;
>      } else {
>        break;
> --
> 2.7.4
>