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ACPICA: Add function to dereference returned reference objects

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Examines the return object from a call to acpi_evaluate_object.
Any Index or RefOf references are automatically dereferenced in
an attempt to return something useful (these reference types
cannot be converted into an external ACPI_OBJECT.)
Lin Ming, Bob Moore.

http://bugzilla.kernel.org/show_bug.cgi?id=11105

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Lin Ming 2008-08-04 13:22:10 +08:00 committed by Len Brown
parent b417d40b9a
commit bbc2413406
1 changed files with 79 additions and 0 deletions
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79
drivers/acpi/namespace/nsxfeval.c
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@ -45,9 +45,14 @@
#include <acpi/acpi.h>
#include <acpi/acnamesp.h>
#include <acpi/acinterp.h>
#include <acpi/amlcode.h>
#define _COMPONENT ACPI_NAMESPACE
ACPI_MODULE_NAME("nsxfeval")
/* Local prototypes */
static void acpi_ns_resolve_references(struct acpi_evaluate_info *info);
#ifdef ACPI_FUTURE_USAGE
/*******************************************************************************
*
@ -69,6 +74,7 @@ ACPI_MODULE_NAME("nsxfeval")
* be valid (non-null)
*
******************************************************************************/
acpi_status
acpi_evaluate_object_typed(acpi_handle handle,
acpi_string pathname,
@ -283,6 +289,10 @@ acpi_evaluate_object(acpi_handle handle,
if (ACPI_SUCCESS(status)) {
/* Dereference Index and ref_of references */
acpi_ns_resolve_references(info);
/* Get the size of the returned object */
status =
@ -350,6 +360,74 @@ acpi_evaluate_object(acpi_handle handle,
ACPI_EXPORT_SYMBOL(acpi_evaluate_object)
/*******************************************************************************
*
* FUNCTION: acpi_ns_resolve_references
*
* PARAMETERS: Info - Evaluation info block
*
* RETURN: Info->return_object is replaced with the dereferenced object
*
* DESCRIPTION: Dereference certain reference objects. Called before an
* internal return object is converted to an external union acpi_object.
*
* Performs an automatic dereference of Index and ref_of reference objects.
* These reference objects are not supported by the union acpi_object, so this is a
* last resort effort to return something useful. Also, provides compatibility
* with other ACPI implementations.
*
* NOTE: does not handle references within returned package objects or nested
* references, but this support could be added later if found to be necessary.
*
******************************************************************************/
static void acpi_ns_resolve_references(struct acpi_evaluate_info *info)
{
union acpi_operand_object *obj_desc = NULL;
struct acpi_namespace_node *node;
/* We are interested in reference objects only */
if (ACPI_GET_OBJECT_TYPE(info->return_object) !=
ACPI_TYPE_LOCAL_REFERENCE) {
return;
}
/*
* Two types of references are supported - those created by Index and
* ref_of operators. A name reference (AML_NAMEPATH_OP) can be converted
* to an union acpi_object, so it is not dereferenced here. A ddb_handle
* (AML_LOAD_OP) cannot be dereferenced, nor can it be converted to
* an union acpi_object.
*/
switch (info->return_object->reference.opcode) {
case AML_INDEX_OP:
obj_desc = *(info->return_object->reference.where);
break;
case AML_REF_OF_OP:
node = info->return_object->reference.object;
if (node) {
obj_desc = node->object;
}
break;
default:
return;
}
/* Replace the existing reference object */
if (obj_desc) {
acpi_ut_add_reference(obj_desc);
acpi_ut_remove_reference(info->return_object);
info->return_object = obj_desc;
}
return;
}
/*******************************************************************************
*
* FUNCTION: acpi_walk_namespace
@ -379,6 +457,7 @@ ACPI_EXPORT_SYMBOL(acpi_evaluate_object)
* function, etc.
*
******************************************************************************/
acpi_status
acpi_walk_namespace(acpi_object_type type,
acpi_handle start_object,