1 files changed, 41 insertions, 46 deletions

diff --git a/drivers/acpi/dispatcher/dsobject.c b/drivers/acpi/dispatcher/dsobject.c
index aaeb9f987ecc..f9f6862b1dff 100644
--- a/drivers/acpi/dispatcher/dsobject.c
+++ b/drivers/acpi/dispatcher/dsobject.c
@@ -260,7 +260,7 @@ acpi_ds_build_internal_buffer_obj(struct acpi_walk_state *walk_state,
         }
 
         obj_desc->buffer.flags |= AOPOBJ_DATA_VALID;
-        op->common.node = (struct acpi_namespace_node *)obj_desc;
+        op->common.node = ACPI_CAST_PTR(struct acpi_namespace_node, obj_desc);
         return_ACPI_STATUS(AE_OK);
 }
 
@@ -270,7 +270,8 @@ acpi_ds_build_internal_buffer_obj(struct acpi_walk_state *walk_state,
  *
  * PARAMETERS:  walk_state      - Current walk state
  *              Op              - Parser object to be translated
- *              package_length  - Number of elements in the package
+ *              element_count   - Number of elements in the package - this is
+ *                                the num_elements argument to Package()
  *              obj_desc_ptr    - Where the ACPI internal object is returned
  *
  * RETURN:      Status
@@ -278,18 +279,29 @@ acpi_ds_build_internal_buffer_obj(struct acpi_walk_state *walk_state,
  * DESCRIPTION: Translate a parser Op package object to the equivalent
  *              namespace object
  *
+ * NOTE: The number of elements in the package will be always be the num_elements
+ * count, regardless of the number of elements in the package list. If
+ * num_elements is smaller, only that many package list elements are used.
+ * if num_elements is larger, the Package object is padded out with
+ * objects of type Uninitialized (as per ACPI spec.)
+ *
+ * Even though the ASL compilers do not allow num_elements to be smaller
+ * than the Package list length (for the fixed length package opcode), some
+ * BIOS code modifies the AML on the fly to adjust the num_elements, and
+ * this code compensates for that. This also provides compatibility with
+ * other AML interpreters.
+ *
  ******************************************************************************/
 
 acpi_status
 acpi_ds_build_internal_package_obj(struct acpi_walk_state *walk_state,
                                    union acpi_parse_object *op,
-                                   u32 package_length,
+                                   u32 element_count,
                                    union acpi_operand_object **obj_desc_ptr)
 {
         union acpi_parse_object *arg;
         union acpi_parse_object *parent;
         union acpi_operand_object *obj_desc = NULL;
-        u32 package_list_length;
         acpi_status status = AE_OK;
         acpi_native_uint i;
 
@@ -318,43 +330,13 @@ acpi_ds_build_internal_package_obj(struct acpi_walk_state *walk_state,
                 obj_desc->package.node = parent->common.node;
         }
 
-        /* Count the *actual* number of items in the package list */
-
-        arg = op->common.value.arg;
-        arg = arg->common.next;
-        for (package_list_length = 0; arg; package_list_length++) {
-                arg = arg->common.next;
-        }
-
-        /*
-         * The number of elements in the package will be the lesser of the
-         * specified element count and the length of the initializer list.
-         *
-         * Even though the ASL compilers do not allow this to happen (for the
-         * fixed length package opcode), some BIOS code modifies the AML on the
-         * fly to adjust the package length, and this code compensates for that.
-         * This also provides compatibility with other AML interpreters.
-         */
-        obj_desc->package.count = package_length;
-
-        if (package_list_length != package_length) {
-                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-                                  "Package length mismatch, using lesser of %X(Length Arg) and %X(AML Length)\n",
-                                  package_length, package_list_length));
-
-                if (package_list_length < package_length) {
-                        obj_desc->package.count = package_list_length;
-                }
-        }
-
         /*
-         * Allocate the pointer array (array of pointers to the
-         * individual objects). Add an extra pointer slot so
-         * that the list is always null terminated.
+         * Allocate the element array (array of pointers to the individual
+         * objects) based on the num_elements parameter. Add an extra pointer slot
+         * so that the list is always null terminated.
          */
         obj_desc->package.elements = ACPI_ALLOCATE_ZEROED(((acpi_size)
-                                                           obj_desc->package.
-                                                           count +
+                                                           element_count +
                                                            1) * sizeof(void *));
 
         if (!obj_desc->package.elements) {
@@ -362,15 +344,20 @@ acpi_ds_build_internal_package_obj(struct acpi_walk_state *walk_state,
                 return_ACPI_STATUS(AE_NO_MEMORY);
         }
 
+        obj_desc->package.count = element_count;
+
         /*
-         * Initialize all elements of the package
+         * Initialize the elements of the package, up to the num_elements count.
+         * Package is automatically padded with uninitialized (NULL) elements
+         * if num_elements is greater than the package list length. Likewise,
+         * Package is truncated if num_elements is less than the list length.
          */
         arg = op->common.value.arg;
         arg = arg->common.next;
-        for (i = 0; i < obj_desc->package.count; i++) {
+        for (i = 0; arg && (i < element_count); i++) {
                 if (arg->common.aml_opcode == AML_INT_RETURN_VALUE_OP) {
 
-                        /* Object (package or buffer) is already built */
+                        /* This package element is already built, just get it */
 
                         obj_desc->package.elements[i] =
                             ACPI_CAST_PTR(union acpi_operand_object,
@@ -384,8 +371,14 @@ acpi_ds_build_internal_package_obj(struct acpi_walk_state *walk_state,
                 arg = arg->common.next;
         }
 
+        if (!arg) {
+                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+                                  "Package List length larger than NumElements count (%X), truncated\n",
+                                  element_count));
+        }
+
         obj_desc->package.flags |= AOPOBJ_DATA_VALID;
-        op->common.node = (struct acpi_namespace_node *)obj_desc;
+        op->common.node = ACPI_CAST_PTR(struct acpi_namespace_node, obj_desc);
         return_ACPI_STATUS(status);
 }
 
@@ -499,8 +492,9 @@ acpi_ds_init_object_from_op(struct acpi_walk_state *walk_state,
                 /*
                  * Defer evaluation of Buffer term_arg operand
                  */
-                obj_desc->buffer.node = (struct acpi_namespace_node *)
-                    walk_state->operands[0];
+                obj_desc->buffer.node =
+                    ACPI_CAST_PTR(struct acpi_namespace_node,
+                                  walk_state->operands[0]);
                 obj_desc->buffer.aml_start = op->named.data;
                 obj_desc->buffer.aml_length = op->named.length;
                 break;
@@ -510,8 +504,9 @@ acpi_ds_init_object_from_op(struct acpi_walk_state *walk_state,
                 /*
                  * Defer evaluation of Package term_arg operand
                  */
-                obj_desc->package.node = (struct acpi_namespace_node *)
-                    walk_state->operands[0];
+                obj_desc->package.node =
+                    ACPI_CAST_PTR(struct acpi_namespace_node,
+                                  walk_state->operands[0]);
                 obj_desc->package.aml_start = op->named.data;
                 obj_desc->package.aml_length = op->named.length;
                 break;