Re: [edk2-devel] [PATCH v3 2/4] DynamicTablesPkg: Add support for simple method\r invocation.

["PierreGondois" <pierre.gondois@arm.com>]

Hello Jeff,
Thanks for the new serie, I think there is still a minor issue in the error
handling in this patch,

On 9/11/23 20:07, Jeff Brasen wrote:
> Add support to add Return objects via AML that pass a single integer
> argument to the named method.
> 
> Bug 4063340

All the patches have this Bug id, is it related to
https://bugzilla.tianocore.org/ ?
If this is a private id, I think it should be removed,

> 
> Signed-off-by: Jeff Brasen <jbrasen@nvidia.com>
> Reviewed-by: Swatisri Kantamsetti <swatisrik@nvidia.com>
> Reviewed-by: Ashish Singhal <ashishsingha@nvidia.com>
> ---
>   .../Include/Library/AmlLib/AmlLib.h           |  54 ++++
>   .../Common/AmlLib/CodeGen/AmlCodeGen.c        | 236 ++++++++++++++++++
>   2 files changed, 290 insertions(+)
> 
> diff --git a/DynamicTablesPkg/Include/Library/AmlLib/AmlLib.h b/DynamicTablesPkg/Include/Library/AmlLib/AmlLib.h
> index d201ae9499..b82c7a3ce8 100644
> --- a/DynamicTablesPkg/Include/Library/AmlLib/AmlLib.h
> +++ b/DynamicTablesPkg/Include/Library/AmlLib/AmlLib.h
> @@ -1194,6 +1194,60 @@ AmlCodeGenMethodRetInteger (
>     OUT       AML_OBJECT_NODE_HANDLE  *NewObjectNode        OPTIONAL
>     );
>   
> +/** AML code generation for a method returning a NameString that takes an
> +    integer argument.
> +
> +  AmlCodeGenMethodRetNameStringIntegerArgument (
> +    "MET0", "MET1", 1, TRUE, 3, 5, ParentNode, NewObjectNode
> +    );
> +  is equivalent of the following ASL code:
> +    Method(MET0, 1, Serialized, 3) {
> +      Return (MET1 (5))
> +    }
> +
> +  The ASL parameters "ReturnType" and "ParameterTypes" are not asked
> +  in this function. They are optional parameters in ASL.
> +
> +  @param [in]  MethodNameString     The new Method's name.
> +                                    Must be a NULL-terminated ASL NameString
> +                                    e.g.: "MET0", "_SB.MET0", etc.
> +                                    The input string is copied.
> +  @param [in]  ReturnedNameString   The name of the object returned by the
> +                                    method. Optional parameter, can be:
> +                                     - NULL (ignored).
> +                                     - A NULL-terminated ASL NameString.
> +                                       e.g.: "MET0", "_SB.MET0", etc.
> +                                       The input string is copied.
> +  @param [in]  NumArgs              Number of arguments.
> +                                    Must be 0 <= NumArgs <= 6.
> +  @param [in]  IsSerialized         TRUE is equivalent to Serialized.
> +                                    FALSE is equivalent to NotSerialized.
> +                                    Default is NotSerialized in ASL spec.
> +  @param [in]  SyncLevel            Synchronization level for the method.
> +                                    Must be 0 <= SyncLevel <= 15.
> +                                    Default is 0 in ASL.
> +  @param [in]  IntegerArgument      Argument to pass to the NameString.
> +  @param [in]  ParentNode           If provided, set ParentNode as the parent
> +                                    of the node created.
> +  @param [out] NewObjectNode        If success, contains the created node.
> +
> +  @retval EFI_SUCCESS             Success.
> +  @retval EFI_INVALID_PARAMETER   Invalid parameter.
> +  @retval EFI_OUT_OF_RESOURCES    Failed to allocate memory.
> +**/
> +EFI_STATUS
> +EFIAPI
> +AmlCodeGenMethodRetNameStringIntegerArgument (
> +  IN  CONST CHAR8                   *MethodNameString,
> +  IN  CONST CHAR8                   *ReturnedNameString   OPTIONAL,
> +  IN        UINT8                   NumArgs,
> +  IN        BOOLEAN                 IsSerialized,
> +  IN        UINT8                   SyncLevel,
> +  IN        UINT64                  IntegerArgument,
> +  IN        AML_NODE_HANDLE         ParentNode           OPTIONAL,
> +  OUT       AML_OBJECT_NODE_HANDLE  *NewObjectNode        OPTIONAL
> +  );
> +
>   /** Create a _LPI name.
>   
>     AmlCreateLpiNode ("_LPI", 0, 1, ParentNode, &LpiNode) is
> diff --git a/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c b/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
> index 88537b7e2d..53c537e2d3 100644
> --- a/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
> +++ b/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
> @@ -1881,6 +1881,130 @@ AmlCodeGenReturnInteger (
>     return Status;
>   }
>   
> +/** AML code generation for a Return object node,
> +    returning the object as an input NameString with a integer argument.
> +
> +  AmlCodeGenReturn ("NAM1", 6, ParentNode, NewObjectNode) is
> +  equivalent of the following ASL code:
> +    Return(NAM1 (6))
> +
> +  The ACPI 6.3 specification, s20.2.5.3 "Type 1 Opcodes Encoding" states:
> +    DefReturn := ReturnOp ArgObject
> +    ReturnOp := 0xA4
> +    ArgObject := TermArg => DataRefObject
> +
> +  Thus, the ReturnNode must be evaluated as a DataRefObject. It can
> +  be a NameString referencing an object. As this CodeGen Api doesn't
> +  do semantic checking, it is strongly advised to check the AML bytecode
> +  generated by this function against an ASL compiler.
> +
> +  The ReturnNode must be generated inside a Method body scope.
> +
> +  @param [in]  NameString     The object referenced by this NameString
> +                              is returned by the Return ASL statement.
> +                              Must be a NULL-terminated ASL NameString
> +                              e.g.: "NAM1", "_SB.NAM1", etc.
> +                              The input string is copied.
> +  @param [in]  Integer        Argument to pass to the NameString
> +  @param [in]  ParentNode     If provided, set ParentNode as the parent
> +                              of the node created.
> +                              Must be a MethodOp node.
> +  @param [out] NewObjectNode  If success, contains the created node.
> +
> +  @retval EFI_SUCCESS             Success.
> +  @retval EFI_INVALID_PARAMETER   Invalid parameter.
> +  @retval EFI_OUT_OF_RESOURCES    Failed to allocate memory.
> +**/
> +STATIC
> +EFI_STATUS
> +EFIAPI
> +AmlCodeGenReturnNameStringIntegerArgument (
> +  IN  CONST CHAR8            *NameString,
> +  IN        UINT64           Integer,
> +  IN        AML_NODE_HEADER  *ParentNode      OPTIONAL,
> +  OUT       AML_OBJECT_NODE  **NewObjectNode   OPTIONAL
> +  )
> +{
> +  EFI_STATUS       Status;
> +  AML_DATA_NODE    *DataNode;
> +  AML_OBJECT_NODE  *IntNode;
> +  CHAR8            *AmlNameString;
> +  UINT32           AmlNameStringSize;
> +  AML_OBJECT_NODE  *ObjectNode;
> +
> +  DataNode   = NULL;
> +  IntNode    = NULL;
> +  ObjectNode = NULL;
> +
> +  Status = ConvertAslNameToAmlName (NameString, &AmlNameString);
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    return Status;
> +  }
> +
> +  Status = AmlGetNameStringSize (AmlNameString, &AmlNameStringSize);
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto exit_handler;
> +  }
> +
> +  Status = AmlCreateDataNode (
> +             EAmlNodeDataTypeNameString,
> +             (UINT8 *)AmlNameString,
> +             AmlNameStringSize,
> +             &DataNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto exit_handler;
> +  }
> +
> +  Status = AmlCodeGenInteger (Integer, &IntNode);
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);

If we fail here, I think DataNode would not be freed,

> +    goto exit_handler;
> +  }
> +
> +  // AmlCodeGenReturn() deletes DataNode if error.
> +  Status = AmlCodeGenReturn (
> +             (AML_NODE_HEADER *)DataNode,
> +             ParentNode,
> +             &ObjectNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto exit_handler;
> +  }
> +
> +  Status = AmlVarListAddTail (
> +             (AML_NODE_HANDLE)ObjectNode,
> +             (AML_NODE_HANDLE)IntNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto exit_handler;
> +  }
> +
> +  if (NewObjectNode != 0) {
> +    *NewObjectNode = ObjectNode;
> +  }

If everything succeeds, then IntNode and ObjectNode will be
deleted. I think this is problematic as these are nodes that
have been attached to the AML tree, so if I'm not mistaken,
I don't think the function should produce the expected result.

I think it should look like this instead (this is not tested):
------
   Status = AmlVarListAddTail (
              (AML_NODE_HANDLE)ObjectNode,
              (AML_NODE_HANDLE)IntNode
              );
   if (EFI_ERROR (Status)) {
     ASSERT (0);
     goto exit_handler;
   }

   IntNode = NULL;

   if (NewObjectNode != 0) {
     *NewObjectNode = ObjectNode;
   }

   goto exit_handler;

error_handler:
   if (IntNode != NULL) {
     AmlDeleteTree ((AML_NODE_HANDLE)IntNode);
   }

   if (ObjectNode != NULL) {
     AmlDeleteTree ((AML_NODE_HANDLE)ObjectNode);
   }

exit_handler:
   if (AmlNameString != NULL) {
     FreePool (AmlNameString);
   }

   return Status;
}
------

Some 'goto exit_handler' might also need to be changed to
'goto error_handler',

Otherwise, the other patches look good to me,
Regards,
Pierre

> +
> +exit_handler:
> +  if (AmlNameString != NULL) {
> +    FreePool (AmlNameString);
> +  }
> +
> +  if (IntNode != NULL) {
> +    AmlDeleteTree ((AML_NODE_HANDLE)IntNode);
> +  }
> +
> +  if (ObjectNode != NULL) {
> +    AmlDeleteTree ((AML_NODE_HANDLE)ObjectNode);
> +  }
> +
> +  return Status;
> +}
> +
>   /** AML code generation for a method returning a NameString.
>   
>     AmlCodeGenMethodRetNameString (
> @@ -1989,6 +2113,118 @@ error_handler:
>     return Status;
>   }
>   
> +/** AML code generation for a method returning a NameString that takes an
> +    integer argument.
> +
> +  AmlCodeGenMethodRetNameStringIntegerArgument (
> +    "MET0", "MET1", 1, TRUE, 3, 5, ParentNode, NewObjectNode
> +    );
> +  is equivalent of the following ASL code:
> +    Method(MET0, 1, Serialized, 3) {
> +      Return (MET1 (5))
> +    }
> +
> +  The ASL parameters "ReturnType" and "ParameterTypes" are not asked
> +  in this function. They are optional parameters in ASL.
> +
> +  @param [in]  MethodNameString     The new Method's name.
> +                                    Must be a NULL-terminated ASL NameString
> +                                    e.g.: "MET0", "_SB.MET0", etc.
> +                                    The input string is copied.
> +  @param [in]  ReturnedNameString   The name of the object returned by the
> +                                    method. Optional parameter, can be:
> +                                     - NULL (ignored).
> +                                     - A NULL-terminated ASL NameString.
> +                                       e.g.: "MET0", "_SB.MET0", etc.
> +                                       The input string is copied.
> +  @param [in]  NumArgs              Number of arguments.
> +                                    Must be 0 <= NumArgs <= 6.
> +  @param [in]  IsSerialized         TRUE is equivalent to Serialized.
> +                                    FALSE is equivalent to NotSerialized.
> +                                    Default is NotSerialized in ASL spec.
> +  @param [in]  SyncLevel            Synchronization level for the method.
> +                                    Must be 0 <= SyncLevel <= 15.
> +                                    Default is 0 in ASL.
> +  @param [in]  IntegerArgument      Argument to pass to the NameString.
> +  @param [in]  ParentNode           If provided, set ParentNode as the parent
> +                                    of the node created.
> +  @param [out] NewObjectNode        If success, contains the created node.
> +
> +  @retval EFI_SUCCESS             Success.
> +  @retval EFI_INVALID_PARAMETER   Invalid parameter.
> +  @retval EFI_OUT_OF_RESOURCES    Failed to allocate memory.
> +**/
> +EFI_STATUS
> +EFIAPI
> +AmlCodeGenMethodRetNameStringIntegerArgument (
> +  IN  CONST CHAR8                   *MethodNameString,
> +  IN  CONST CHAR8                   *ReturnedNameString   OPTIONAL,
> +  IN        UINT8                   NumArgs,
> +  IN        BOOLEAN                 IsSerialized,
> +  IN        UINT8                   SyncLevel,
> +  IN        UINT64                  IntegerArgument,
> +  IN        AML_NODE_HANDLE         ParentNode           OPTIONAL,
> +  OUT       AML_OBJECT_NODE_HANDLE  *NewObjectNode        OPTIONAL
> +  )
> +{
> +  EFI_STATUS              Status;
> +  AML_OBJECT_NODE_HANDLE  MethodNode;
> +
> +  if ((MethodNameString == NULL)  ||
> +      ((ParentNode == NULL) && (NewObjectNode == NULL)))
> +  {
> +    ASSERT (0);
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  // Create a Method named MethodNameString.
> +  Status = AmlCodeGenMethod (
> +             MethodNameString,
> +             NumArgs,
> +             IsSerialized,
> +             SyncLevel,
> +             NULL,
> +             &MethodNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    return Status;
> +  }
> +
> +  // Return ReturnedNameString if provided.
> +  if (ReturnedNameString != NULL) {
> +    Status = AmlCodeGenReturnNameStringIntegerArgument (
> +               ReturnedNameString,
> +               IntegerArgument,
> +               (AML_NODE_HANDLE)MethodNode,
> +               NULL
> +               );
> +    if (EFI_ERROR (Status)) {
> +      ASSERT (0);
> +      goto error_handler;
> +    }
> +  }
> +
> +  Status = LinkNode (
> +             MethodNode,
> +             ParentNode,
> +             NewObjectNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler;
> +  }
> +
> +  return Status;
> +
> +error_handler:
> +  if (MethodNode != NULL) {
> +    AmlDeleteTree ((AML_NODE_HANDLE)MethodNode);
> +  }
> +
> +  return Status;
> +}
> +
>   /** AML code generation for a method returning an Integer.
>   
>     AmlCodeGenMethodRetInteger (


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