Re: [PATCH v3 1/1] ArmPkg/OpteeLib: Add APIs to communicate with OP-TEE

[Leif Lindholm <leif.lindholm@linaro.org>]

On Wed, Oct 03, 2018 at 11:33:01AM +0200, Ard Biesheuvel wrote:
> On 3 October 2018 at 09:43, Sumit Garg <sumit.garg@linaro.org> wrote:
> > Add following APIs to communicate with OP-TEE pseudo/early TAs:
> > 1. OpteeInit
> > 2. OpteeOpenSession
> > 3. OpteeCloseSession
> > 4. OpteeInvokeFunc
> >
> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > Cc: Leif Lindholm <leif.lindholm@linaro.org>
> > Cc: Michael D Kinney <michael.d.kinney@intel.com>
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> 
> Given the outcome of the GP discussion, I'm fine with this approach. Leif?

Apologies for the delay, I needed some time to think it over.

I'm not super happy about this approach, but I'm happier with this
than I would be with leaving the functionality out of the upstream
tree. I really hope we can get that license either changed or dropped
completely.

I do have a few comments below.

> > ---
> >  ArmPkg/Include/Library/OpteeLib.h    |  90 +++++++++
> >  ArmPkg/Library/OpteeLib/Optee.c      | 357 +++++++++++++++++++++++++++++++++++
> >  ArmPkg/Library/OpteeLib/OpteeLib.inf |   2 +
> >  ArmPkg/Library/OpteeLib/OpteeSmc.h   |  43 +++++

Could you follow the instructions in
https://github.com/tianocore/tianocore.github.io/wiki/Laszlo's-unkempt-git-guide-for-edk2-contributors-and-maintainers#contrib-23
when generating future patches?
The --stat* effects aren't apparent here, but the -O ones are.

> >  4 files changed, 492 insertions(+)
> >  create mode 100644 ArmPkg/Library/OpteeLib/OpteeSmc.h
> >
> > diff --git a/ArmPkg/Include/Library/OpteeLib.h b/ArmPkg/Include/Library/OpteeLib.h
> > index f65d8674d9b8..2d1c60632dfe 100644
> > --- a/ArmPkg/Include/Library/OpteeLib.h
> > +++ b/ArmPkg/Include/Library/OpteeLib.h
> > @@ -25,10 +25,100 @@
> >  #define OPTEE_OS_UID2          0xaf630002
> >  #define OPTEE_OS_UID3          0xa5d5c51b
> >
> > +#define OPTEE_MSG_ATTR_TYPE_NONE                0x0
> > +#define OPTEE_MSG_ATTR_TYPE_VALUE_INPUT         0x1
> > +#define OPTEE_MSG_ATTR_TYPE_VALUE_OUTPUT        0x2
> > +#define OPTEE_MSG_ATTR_TYPE_VALUE_INOUT         0x3
> > +#define OPTEE_MSG_ATTR_TYPE_MEM_INPUT           0x9
> > +#define OPTEE_MSG_ATTR_TYPE_MEM_OUTPUT          0xa
> > +#define OPTEE_MSG_ATTR_TYPE_MEM_INOUT           0xb
> > +
> > +#define OPTEE_MSG_ATTR_TYPE_MASK                0xff
> > +
> > +#define OPTEE_ORIGIN_COMMS                      0x00000002
> > +#define OPTEE_ERROR_COMMS                       0xFFFF000E
> > +
> > +typedef struct {
> > +  UINT64    BufPtr;

If it's a pointer, it has a *.
Otherwise it's an address.

> > +  UINT64    Size;
> > +  UINT64    ShmRef;

Abbreviations in function, variable or type names (other than the ones
defined in [1] are not permitted unless they are explicitly added to a
glossary section of the source file header. Where possible, just write
out the name in full.

[1] https://edk2-docs.gitbooks.io/edk-ii-c-coding-standards-specification/content/v/release/2.20/4_naming_conventions/#table-2-efi-supported-abbreviations

BufPtr (as a name) gets a pass since it's unambiguous and we already
have a bunch of those in the codebase. ShmRef needs to be clear.

(This comment also applies to a lot of things below, I won't point
them all out unless asked to.)

> > +} OPTEE_MSG_PARAM_MEM;
> > +
> > +typedef struct {
> > +  UINT64    A;
> > +  UINT64    B;
> > +  UINT64    C;
> > +} OPTEE_MSG_PARAM_VALUE;
> > +
> > +typedef struct {
> > +  UINT64 Attr;
> > +  union {
> > +    OPTEE_MSG_PARAM_MEM      Mem;
> > +    OPTEE_MSG_PARAM_VALUE    Value;
> > +  } U;
> > +} OPTEE_MSG_PARAM;
> > +
> > +#define MAX_PARAMS           4

This is a very localised macro with a very globalised name.
Suggest adding an OPTEE_ prefix, but also something describing what it
is the maximum parameters for. CALL_?

> > +
> > +typedef struct {
> > +        UINT32             Cmd;
> > +        UINT32             Func;
> > +        UINT32             Session;
> > +        UINT32             CancelId;
> > +        UINT32             Pad;
> > +        UINT32             Ret;
> > +        UINT32             RetOrigin;
> > +        UINT32             NumParams;
> > +
> > +        // NumParams tells the actual number of element in Params
> > +        OPTEE_MSG_PARAM    Params[MAX_PARAMS];
> > +} OPTEE_MSG_ARG;
> > +
> > +#define OPTEE_UUID_LEN       16

UUIDs are UUIDs. If optee decides on an incompatible format, we may
have an interoperability issue. I assume this is not the case, so
perhaps replace with sizeof (EFI_GUID) at each point of use?

> > +
> > +typedef struct {
> > +        UINT8     Uuid[OPTEE_UUID_LEN]; // [in] UUID of the Trusted Application

Is there a strong reason for not using EFI_GUID here?

> > +        UINT32    Session;              // [out] Session id
> > +        UINT32    Ret;                  // [out] Return value
> > +        UINT32    RetOrigin;            // [out] Origin of the return value
> > +} OPTEE_OPEN_SESSION_ARG;
> > +
> > +typedef struct {
> > +        UINT32             Func;    // [in] Trusted App func, specific to the TA
> > +        UINT32             Session; // [in] Session id
> > +        UINT32             Ret;     // [out] Return value
> > +        UINT32             RetOrigin; // [out] Origin of the return value
> > +        OPTEE_MSG_PARAM    Params[MAX_PARAMS]; // Params for func to be invoked
> > +} OPTEE_INVOKE_FUNC_ARG;
> > +
> >  BOOLEAN
> >  EFIAPI
> >  IsOpteePresent (
> >    VOID
> >    );
> >
> > +EFI_STATUS
> > +EFIAPI
> > +OpteeInit (
> > +  VOID
> > +  );
> > +
> > +EFI_STATUS
> > +EFIAPI
> > +OpteeOpenSession (
> > +  IN OUT OPTEE_OPEN_SESSION_ARG      *OpenSessionArg
> > +  );
> > +
> > +EFI_STATUS
> > +EFIAPI
> > +OpteeCloseSession (
> > +  IN UINT32                      Session
> > +  );
> > +
> > +EFI_STATUS
> > +EFIAPI
> > +OpteeInvokeFunc (
> > +  IN OUT OPTEE_INVOKE_FUNC_ARG       *InvokeFuncArg
> > +  );
> > +
> >  #endif
> > diff --git a/ArmPkg/Library/OpteeLib/Optee.c b/ArmPkg/Library/OpteeLib/Optee.c
> > index 574527f8b5ea..bf7872cbbce0 100644
> > --- a/ArmPkg/Library/OpteeLib/Optee.c
> > +++ b/ArmPkg/Library/OpteeLib/Optee.c
> > @@ -14,11 +14,18 @@
> >
> >  **/
> >
> > +#include <Library/ArmMmuLib.h>
> >  #include <Library/ArmSmcLib.h>
> > +#include <Library/BaseMemoryLib.h>
> >  #include <Library/BaseLib.h>
> > +#include <Library/DebugLib.h>
> >  #include <Library/OpteeLib.h>
> >
> >  #include <IndustryStandard/ArmStdSmc.h>
> > +#include <OpteeSmc.h>
> > +#include <Uefi.h>
> > +
> > +STATIC OPTEE_SHARED_MEMORY_INFO OpteeShmInfo = { 0 };
> >
> >  /**
> >    Check for OP-TEE presence.
> > @@ -31,6 +38,7 @@ IsOpteePresent (
> >  {
> >    ARM_SMC_ARGS ArmSmcArgs;
> >
> > +  ZeroMem (&ArmSmcArgs, sizeof (ARM_SMC_ARGS));
> >    // Send a Trusted OS Calls UID command
> >    ArmSmcArgs.Arg0 = ARM_SMC_ID_TOS_UID;
> >    ArmCallSmc (&ArmSmcArgs);
> > @@ -44,3 +52,352 @@ IsOpteePresent (
> >      return FALSE;
> >    }
> >  }
> > +
> > +STATIC
> > +EFI_STATUS
> > +OpteeShmMemRemap (
> > +  VOID
> > +  )
> > +{
> > +  ARM_SMC_ARGS                 ArmSmcArgs;
> > +  EFI_PHYSICAL_ADDRESS         Paddr;
> > +  EFI_PHYSICAL_ADDRESS         Start;
> > +  EFI_PHYSICAL_ADDRESS         End;
> > +  EFI_STATUS                   Status;
> > +  UINTN                        Size;
> > +
> > +  ZeroMem (&ArmSmcArgs, sizeof (ARM_SMC_ARGS));
> > +  ArmSmcArgs.Arg0 = OPTEE_SMC_GET_SHM_CONFIG;
> > +
> > +  ArmCallSmc (&ArmSmcArgs);
> > +  if (ArmSmcArgs.Arg0 != OPTEE_SMC_RETURN_OK) {
> > +    DEBUG ((DEBUG_WARN, "OP-TEE shared memory not supported\n"));
> > +    return EFI_UNSUPPORTED;
> > +  }
> > +
> > +  if (ArmSmcArgs.Arg3 != OPTEE_SMC_SHM_CACHED) {
> > +    DEBUG ((DEBUG_WARN, "OP-TEE: Only normal cached shared memory supported\n"));
> > +    return EFI_UNSUPPORTED;
> > +  }
> > +
> > +  Start = (ArmSmcArgs.Arg1 + SIZE_4KB - 1) & ~(SIZE_4KB - 1);
> > +  End = (ArmSmcArgs.Arg1 + ArmSmcArgs.Arg2) & ~(SIZE_4KB - 1);
> > +  Paddr = Start;
> > +  Size = End - Start;
> > +
> > +  if (Size < SIZE_4KB) {
> > +    DEBUG ((DEBUG_WARN, "OP-TEE shared memory too small\n"));
> > +    return EFI_BUFFER_TOO_SMALL;
> > +  }
> > +
> > +  Status = ArmSetMemoryAttributes (Paddr, Size, EFI_MEMORY_WB);
> > +  if (EFI_ERROR (Status)) {
> > +    return Status;
> > +  }
> > +
> > +  OpteeShmInfo.Base = (UINTN)Paddr;

Would PHYSICAL_ADDRESS (always 64-bit) be more correct here, or is the
OP-TEE end seeing this struct as always having fields of native width?

(This is where the ordefile comes in handy, because it means I see the
struct definition first, not its use.)

> > +  OpteeShmInfo.Size = Size;
> > +
> > +  return EFI_SUCCESS;
> > +}
> > +
> > +EFI_STATUS
> > +EFIAPI
> > +OpteeInit (
> > +  VOID
> > +  )
> > +{
> > +  EFI_STATUS      Status;
> > +
> > +  if (!IsOpteePresent ()) {
> > +    DEBUG ((DEBUG_WARN, "OP-TEE not present\n"));
> > +    return EFI_UNSUPPORTED;
> > +  }
> > +
> > +  Status = OpteeShmMemRemap ();
> > +  if (EFI_ERROR (Status)) {
> > +    DEBUG ((DEBUG_WARN, "OP-TEE shared memory remap failed\n"));
> > +    return Status;
> > +  }
> > +
> > +  return EFI_SUCCESS;
> > +}
> > +
> > +/**
> > +  Does Standard SMC to OP-TEE in secure world.
> > +
> > +  @param[in]  Parg   Physical address of message to pass to secure world
> > +
> > +  @return            0 on success, secure world return code otherwise
> > +
> > +**/
> > +STATIC
> > +UINT32
> > +OpteeCallWithArg (
> > +  IN EFI_PHYSICAL_ADDRESS Parg
> > +  )
> > +{
> > +  ARM_SMC_ARGS ArmSmcArgs;
> > +
> > +  ZeroMem (&ArmSmcArgs, sizeof (ARM_SMC_ARGS));
> > +  ArmSmcArgs.Arg0 = OPTEE_SMC_CALL_WITH_ARG;
> > +  ArmSmcArgs.Arg1 = (UINT32)(Parg >> 32);
> > +  ArmSmcArgs.Arg2 = (UINT32)Parg;
> > +
> > +  while (TRUE) {
> > +    ArmCallSmc (&ArmSmcArgs);
> > +
> > +    if (ArmSmcArgs.Arg0 == OPTEE_SMC_RETURN_RPC_FOREIGN_INTR) {
> > +      //
> > +      // 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.
> > +      //
> > +      ArmSmcArgs.Arg0 = OPTEE_SMC_RETURN_FROM_RPC;
> > +    } else {
> > +      break;
> > +    }
> > +  }
> > +
> > +  return ArmSmcArgs.Arg0;
> > +}
> > +
> > +EFI_STATUS
> > +EFIAPI
> > +OpteeOpenSession (
> > +  IN OUT OPTEE_OPEN_SESSION_ARG      *OpenSessionArg
> > +  )
> > +{
> > +  OPTEE_MSG_ARG    *MsgArg;
> > +
> > +  MsgArg = NULL;
> > +
> > +  if (OpteeShmInfo.Base == 0) {
> > +    DEBUG ((DEBUG_WARN, "OP-TEE not initialized\n"));
> > +    return EFI_NOT_STARTED;
> > +  }
> > +
> > +  MsgArg = (OPTEE_MSG_ARG *)OpteeShmInfo.Base;
> > +  ZeroMem (MsgArg, sizeof (OPTEE_MSG_ARG));
> > +
> > +  MsgArg->Cmd = OPTEE_MSG_CMD_OPEN_SESSION;
> > +
> > +  //
> > +  // Initialize and add the meta parameters needed when opening a
> > +  // session.
> > +  //
> > +  MsgArg->Params[0].Attr = OPTEE_MSG_ATTR_TYPE_VALUE_INPUT |
> > +                           OPTEE_MSG_ATTR_META;
> > +  MsgArg->Params[1].Attr = OPTEE_MSG_ATTR_TYPE_VALUE_INPUT |
> > +                           OPTEE_MSG_ATTR_META;
> > +  CopyMem (&MsgArg->Params[0].U.Value, OpenSessionArg->Uuid, OPTEE_UUID_LEN);
> > +  ZeroMem (&MsgArg->Params[1].U.Value, OPTEE_UUID_LEN);
> > +  MsgArg->Params[1].U.Value.C = TEE_LOGIN_PUBLIC;
> > +
> > +  MsgArg->NumParams = 2;
> > +
> > +  if (OpteeCallWithArg ((EFI_PHYSICAL_ADDRESS)MsgArg)) {
> > +    MsgArg->Ret = OPTEE_ERROR_COMMS;
> > +    MsgArg->RetOrigin = OPTEE_ORIGIN_COMMS;
> > +  }
> > +
> > +  OpenSessionArg->Session = MsgArg->Session;
> > +  OpenSessionArg->Ret = MsgArg->Ret;
> > +  OpenSessionArg->RetOrigin = MsgArg->RetOrigin;
> > +
> > +  return EFI_SUCCESS;
> > +}
> > +
> > +EFI_STATUS
> > +EFIAPI
> > +OpteeCloseSession (
> > +  IN UINT32                      Session
> > +  )
> > +{
> > +  OPTEE_MSG_ARG    *MsgArg;
> > +
> > +  MsgArg = NULL;
> > +
> > +  if (OpteeShmInfo.Base == 0) {
> > +    DEBUG ((DEBUG_WARN, "OP-TEE not initialized\n"));
> > +    return EFI_NOT_STARTED;
> > +  }
> > +
> > +  MsgArg = (OPTEE_MSG_ARG *)OpteeShmInfo.Base;
> > +  ZeroMem (MsgArg, sizeof (OPTEE_MSG_ARG));
> > +
> > +  MsgArg->Cmd = OPTEE_MSG_CMD_CLOSE_SESSION;
> > +  MsgArg->Session = Session;
> > +
> > +  OpteeCallWithArg ((EFI_PHYSICAL_ADDRESS)MsgArg);
> > +
> > +  return EFI_SUCCESS;
> > +}
> > +
> > +STATIC
> > +EFI_STATUS
> > +OpteeToMsgParam (
> > +  OUT OPTEE_MSG_PARAM    *MsgParams,
> > +  IN UINT32              NumParams,
> > +  IN OPTEE_MSG_PARAM     *InParams
> > +  )
> > +{
> > +  UINT32                  Idx;
> > +  UINTN                   ParamShmAddr;
> > +  UINTN                   ShmSize;
> > +  UINTN                   Size;
> > +
> > +  Size = (sizeof (OPTEE_MSG_ARG) + sizeof (UINT64) - 1) & ~(sizeof (UINT64) - 1);
> > +  ParamShmAddr = OpteeShmInfo.Base + Size;
> > +  ShmSize = OpteeShmInfo.Size - Size;
> > +
> > +  for (Idx = 0; Idx < NumParams; Idx++) {
> > +    CONST OPTEE_MSG_PARAM    *Ip;
> > +    OPTEE_MSG_PARAM          *Mp;
> > +    UINT32                   Attr;
> > +
> > +    Ip = InParams + Idx;
> > +    Mp = MsgParams + Idx;
> > +    Attr = Ip->Attr & OPTEE_MSG_ATTR_TYPE_MASK;
> > +
> > +    switch (Attr) {
> > +    case OPTEE_MSG_ATTR_TYPE_NONE:
> > +      Mp->Attr = OPTEE_MSG_ATTR_TYPE_NONE;
> > +      ZeroMem (&Mp->U, sizeof (Mp->U));
> > +      break;
> > +
> > +    case OPTEE_MSG_ATTR_TYPE_VALUE_INPUT:
> > +    case OPTEE_MSG_ATTR_TYPE_VALUE_OUTPUT:
> > +    case OPTEE_MSG_ATTR_TYPE_VALUE_INOUT:
> > +      Mp->Attr = Attr;
> > +      Mp->U.Value.A = Ip->U.Value.A;
> > +      Mp->U.Value.B = Ip->U.Value.B;
> > +      Mp->U.Value.C = Ip->U.Value.C;
> > +      break;
> > +
> > +    case OPTEE_MSG_ATTR_TYPE_MEM_INPUT:
> > +    case OPTEE_MSG_ATTR_TYPE_MEM_OUTPUT:
> > +    case OPTEE_MSG_ATTR_TYPE_MEM_INOUT:
> > +      Mp->Attr = Attr;
> > +
> > +      if (Ip->U.Mem.Size > ShmSize) {
> > +        return EFI_OUT_OF_RESOURCES;
> > +      }
> > +
> > +      CopyMem ((VOID *)ParamShmAddr, (VOID *)Ip->U.Mem.BufPtr, Ip->U.Mem.Size);
> > +      Mp->U.Mem.BufPtr = (UINT64)ParamShmAddr;

While I don't think it's possible for this to end up doing something
unexpected, casting pointers to a higher alignment (which this would
do on 32-bit) is a bad habit to get into.

> > +      Mp->U.Mem.Size = Ip->U.Mem.Size;
> > +
> > +      Size = (Ip->U.Mem.Size + sizeof (UINT64) - 1) & ~(sizeof (UINT64) - 1);
> > +      ParamShmAddr += Size;
> > +      ShmSize -= Size;
> > +      break;
> > +
> > +    default:
> > +      return EFI_INVALID_PARAMETER;
> > +    }
> > +  }
> > +
> > +  return EFI_SUCCESS;
> > +}
> > +
> > +STATIC
> > +EFI_STATUS
> > +OpteeFromMsgParam (
> > +  OUT OPTEE_MSG_PARAM    *OutParams,
> > +  IN UINT32              NumParams,
> > +  IN OPTEE_MSG_PARAM     *MsgParams
> > +  )
> > +{
> > +  UINT32                 Idx;
> > +
> > +  for (Idx = 0; Idx < NumParams; Idx++) {
> > +    OPTEE_MSG_PARAM          *Op;
> > +    CONST OPTEE_MSG_PARAM    *Mp;
> > +    UINT32                   Attr;
> > +
> > +    Op = OutParams + Idx;
> > +    Mp = MsgParams + Idx;
> > +    Attr = Mp->Attr & OPTEE_MSG_ATTR_TYPE_MASK;
> > +
> > +    switch (Attr) {
> > +    case OPTEE_MSG_ATTR_TYPE_NONE:
> > +      Op->Attr = OPTEE_MSG_ATTR_TYPE_NONE;
> > +      ZeroMem (&Op->U, sizeof (Op->U));
> > +      break;
> > +
> > +    case OPTEE_MSG_ATTR_TYPE_VALUE_INPUT:
> > +    case OPTEE_MSG_ATTR_TYPE_VALUE_OUTPUT:
> > +    case OPTEE_MSG_ATTR_TYPE_VALUE_INOUT:
> > +      Op->Attr = Attr;
> > +      Op->U.Value.A = Mp->U.Value.A;
> > +      Op->U.Value.B = Mp->U.Value.B;
> > +      Op->U.Value.C = Mp->U.Value.C;
> > +      break;
> > +
> > +    case OPTEE_MSG_ATTR_TYPE_MEM_INPUT:
> > +    case OPTEE_MSG_ATTR_TYPE_MEM_OUTPUT:
> > +    case OPTEE_MSG_ATTR_TYPE_MEM_INOUT:
> > +      Op->Attr = Attr;
> > +
> > +      if (Mp->U.Mem.Size > Op->U.Mem.Size) {
> > +        return EFI_BAD_BUFFER_SIZE;
> > +      }
> > +
> > +      CopyMem ((VOID *)Op->U.Mem.BufPtr, (VOID *)Mp->U.Mem.BufPtr, Mp->U.Mem.Size);
> > +      Op->U.Mem.Size = Mp->U.Mem.Size;
> > +      break;
> > +
> > +    default:
> > +      return EFI_INVALID_PARAMETER;
> > +    }
> > +  }
> > +
> > +  return EFI_SUCCESS;
> > +}
> > +
> > +EFI_STATUS
> > +EFIAPI
> > +OpteeInvokeFunc (
> > +  IN OUT OPTEE_INVOKE_FUNC_ARG       *InvokeFuncArg
> > +  )
> > +{
> > +  EFI_STATUS       Status;
> > +  OPTEE_MSG_ARG    *MsgArg;
> > +
> > +  MsgArg = NULL;
> > +
> > +  if (OpteeShmInfo.Base == 0) {
> > +    DEBUG ((DEBUG_WARN, "OP-TEE not initialized\n"));
> > +    return EFI_NOT_STARTED;
> > +  }
> > +
> > +  MsgArg = (OPTEE_MSG_ARG *)OpteeShmInfo.Base;
> > +  ZeroMem (MsgArg, sizeof (OPTEE_MSG_ARG));
> > +
> > +  MsgArg->Cmd = OPTEE_MSG_CMD_INVOKE_COMMAND;
> > +  MsgArg->Func = InvokeFuncArg->Func;
> > +  MsgArg->Session = InvokeFuncArg->Session;
> > +
> > +  Status = OpteeToMsgParam (MsgArg->Params, MAX_PARAMS, InvokeFuncArg->Params);
> > +  if (Status)
> > +    return Status;

Always use {} (coding style requirement).

> > +
> > +  MsgArg->NumParams = MAX_PARAMS;
> > +
> > +  if (OpteeCallWithArg ((EFI_PHYSICAL_ADDRESS)MsgArg)) {
> > +    MsgArg->Ret = OPTEE_ERROR_COMMS;
> > +    MsgArg->RetOrigin = OPTEE_ORIGIN_COMMS;
> > +  }
> > +
> > +  if (OpteeFromMsgParam (InvokeFuncArg->Params, MAX_PARAMS, MsgArg->Params)) {
> > +    MsgArg->Ret = OPTEE_ERROR_COMMS;
> > +    MsgArg->RetOrigin = OPTEE_ORIGIN_COMMS;
> > +  }
> > +
> > +  InvokeFuncArg->Ret = MsgArg->Ret;
> > +  InvokeFuncArg->RetOrigin = MsgArg->RetOrigin;
> > +
> > +  return EFI_SUCCESS;
> > +}
> > diff --git a/ArmPkg/Library/OpteeLib/OpteeLib.inf b/ArmPkg/Library/OpteeLib/OpteeLib.inf
> > index 5abd427379cc..e03054a7167d 100644
> > --- a/ArmPkg/Library/OpteeLib/OpteeLib.inf
> > +++ b/ArmPkg/Library/OpteeLib/OpteeLib.inf
> > @@ -23,11 +23,13 @@ [Defines]
> >
> >  [Sources]
> >    Optee.c
> > +  OpteeSmc.h
> >
> >  [Packages]
> >    ArmPkg/ArmPkg.dec
> >    MdePkg/MdePkg.dec
> >
> >  [LibraryClasses]
> > +  ArmMmuLib
> >    ArmSmcLib
> >    BaseLib
> > diff --git a/ArmPkg/Library/OpteeLib/OpteeSmc.h b/ArmPkg/Library/OpteeLib/OpteeSmc.h
> > new file mode 100644
> > index 000000000000..e2ea35784a0a
> > --- /dev/null
> > +++ b/ArmPkg/Library/OpteeLib/OpteeSmc.h
> > @@ -0,0 +1,43 @@
> > +/** @file
> > +  OP-TEE SMC header file.
> > +
> > +  Copyright (c) 2018, Linaro Ltd. All rights reserved.<BR>
> > +
> > +  This program and the accompanying materials
> > +  are licensed and made available under the terms and conditions of the BSD License
> > +  which accompanies this distribution.  The full text of the license may be found at
> > +  http://opensource.org/licenses/bsd-license.php
> > +
> > +  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
> > +  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
> > +
> > +**/
> > +
> > +#ifndef _OPTEE_SMC_H_
> > +#define _OPTEE_SMC_H_
> > +
> > +/* Returned in Arg0 only from Trusted OS functions */
> > +#define OPTEE_SMC_RETURN_OK                     0x0
> > +
> > +#define OPTEE_SMC_RETURN_FROM_RPC               0x32000003
> > +#define OPTEE_SMC_CALL_WITH_ARG                 0x32000004
> > +#define OPTEE_SMC_GET_SHM_CONFIG                0xb2000007
> > +
> > +#define OPTEE_SMC_SHM_CACHED                    1
> > +
> > +#define OPTEE_SMC_RETURN_RPC_FOREIGN_INTR       0xffff0004
> > +
> > +#define OPTEE_MSG_CMD_OPEN_SESSION              0
> > +#define OPTEE_MSG_CMD_INVOKE_COMMAND            1
> > +#define OPTEE_MSG_CMD_CLOSE_SESSION             2
> > +
> > +#define OPTEE_MSG_ATTR_META                     0x100
> > +
> > +#define TEE_LOGIN_PUBLIC                        0x0

I'm a bit apprehensive about taking over the whole TEE namespace in an
implementation-specific header file.
Can/should this be OPTEE_?

> > +
> > +typedef struct {
> > +  UINTN    Base;
> > +  UINTN    Size;
> > +} OPTEE_SHARED_MEMORY_INFO;

(See comments above.)

/
    Leif

> > +
> > +#endif
> > --
> > 2.7.4
> >