Re: [PATCH v1 08/13] DynamicTablesPkg: AML code generation to Return a NameString

["Sami Mujawar" <sami.mujawar@arm.com>]

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Hi Pierre,

Please find my feedback inline marked [SAMI].

Regards,

Sami Mujawar


On 23/06/2021 12:40 PM, Pierre.Gondois@arm.com wrote:
> From: Pierre Gondois <Pierre.Gondois@arm.com>
>
> Add AmlCodeGenReturnNameString() to generate AML code for a
> Return object node, returning the object as a NameString.
>
> AmlCodeGenReturn ("NAM1", ParentNode, NewObjectNode) is
> equivalent of the following ASL code:
>    Return(NAM1)
>
> Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
> ---
>   .../Common/AmlLib/CodeGen/AmlCodeGen.c        | 178 ++++++++++++++++++
>   1 file changed, 178 insertions(+)
>
> diff --git a/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c b/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
> index 32665f7f8d8f..75dadbaf4ac3 100644
> --- a/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
> +++ b/DynamicTablesPkg/Library/Common/AmlLib/CodeGen/AmlCodeGen.c
> @@ -1137,3 +1137,181 @@ error_handler1:
>     }
>     return Status;
>   }
> +
> +/** AML code generation for a Return object node.
> +
> +  AmlCodeGenReturn (ReturnNode, ParentNode, NewObjectNode) is
> +  equivalent of the following ASL code:
> +    Return([Content of the ReturnNode])
> +
> +  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]  ReturnNode     The object returned by the Return ASL statement.
> +                              This node is deleted if an error occurs.
> +  @param [in]  ParentNode     If provided, set ParentNode as the parent
> +                              of the node created.
[SAMI] Can we mention here that the ParentNode must be a MethodOp Node, 
please? Also is it possible to add a check to that effect.
> +  @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
> +AmlCodeGenReturn (
> +  IN  AML_NODE_HEADER     * ReturnNode,
> +  IN  AML_NODE_HEADER     * ParentNode,     OPTIONAL
> +  OUT AML_OBJECT_NODE    ** NewObjectNode   OPTIONAL
> +  )
> +{
> +  EFI_STATUS        Status;
> +  AML_OBJECT_NODE * ObjectNode;
> +
> +  if ((ReturnNode == NULL)  ||
> +      ((ParentNode == NULL) && (NewObjectNode == NULL))) {
> +    ASSERT (0);
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  ObjectNode = NULL;
> +
> +  Status = AmlCreateObjectNode (
> +             AmlGetByteEncodingByOpCode (AML_RETURN_OP, 0),
> +             0,
> +             &ObjectNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler;
> +  }
> +
> +  Status = AmlSetFixedArgument (
> +             ObjectNode,
> +             EAmlParseIndexTerm0,
> +             (AML_NODE_HEADER*)ReturnNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler;
> +  }
> +
> +  ReturnNode = NULL;
> +
> +  Status = LinkNode (
> +             ObjectNode,
> +             ParentNode,
> +             NewObjectNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +    goto error_handler;
> +  }
> +
> +  return Status;
> +
> +error_handler:
> +  AmlDeleteTree (ReturnNode);
[SAMI] Add a check to see if ReturnNode is NULL before deleting.
> +  if (ObjectNode != NULL) {
> +    AmlDeleteTree ((AML_NODE_HEADER*)ObjectNode);
> +  }
> +  return Status;
> +}
> +
> +/** AML code generation for a Return object node,
> +    returning the object as an input NameString.
> +
> +  AmlCodeGenReturn ("NAM1", ParentNode, NewObjectNode) is
> +  equivalent of the following ASL code:
> +    Return(NAM1)
> +
> +  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]  ParentNode     If provided, set ParentNode as the parent
> +                              of the node created.
[SAMI] Same comment as above.
> +  @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
> +AmlCodeGenReturnNameString (
> +  IN  CONST CHAR8               * NameString,
> +  IN        AML_NODE_HEADER     * ParentNode,     OPTIONAL
> +  OUT       AML_OBJECT_NODE    ** NewObjectNode   OPTIONAL
> +  )
> +{
> +  EFI_STATUS          Status;
> +  AML_DATA_NODE     * DataNode;
> +  CHAR8             * AmlNameString;
> +  UINT32              AmlNameStringSize;
> +
> +  DataNode = 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;
> +  }
> +
> +  // AmlCodeGenReturn() deletes DataNode if error.
> +  Status = AmlCodeGenReturn (
> +             (AML_NODE_HEADER*)DataNode,
> +             ParentNode,
> +             NewObjectNode
> +             );
> +  if (EFI_ERROR (Status)) {
> +    ASSERT (0);
> +  }
[SAMI] Can we replace this withASSERT_EFI_ERROR()?
> +
> +exit_handler:
> +  if (AmlNameString != NULL) {
> +    FreePool (AmlNameString);
> +  }
> +  return Status;
> +}


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