drivers/acpi/namespace/nseval.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nseval - Object evaluation, includes control method execution
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2007, R. Byron Moore
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include <acpi/acparser.h>
  46 #include <acpi/acinterp.h>
  47 #include <acpi/acnamesp.h>
  48
  49 #define _COMPONENT          ACPI_NAMESPACE
  50 ACPI_MODULE_NAME("nseval")
  51
  52 /*******************************************************************************
  53  *
  54  * FUNCTION:    acpi_ns_evaluate
  55  *
  56  * PARAMETERS:  Info            - Evaluation info block, contains:
  57  *                  prefix_node     - Prefix or Method/Object Node to execute
  58  *                  Pathname        - Name of method to execute, If NULL, the
  59  *                                    Node is the object to execute
  60  *                  Parameters      - List of parameters to pass to the method,
  61  *                                    terminated by NULL. Params itself may be
  62  *                                    NULL if no parameters are being passed.
  63  *                  return_object   - Where to put method's return value (if
  64  *                                    any). If NULL, no value is returned.
  65  *                  parameter_type  - Type of Parameter list
  66  *                  return_object   - Where to put method's return value (if
  67  *                                    any). If NULL, no value is returned.
  68  *                  Flags           - ACPI_IGNORE_RETURN_VALUE to delete return
  69  *
  70  * RETURN:      Status
  71  *
  72  * DESCRIPTION: Execute a control method or return the current value of an
  73  *              ACPI namespace object.
  74  *
  75  * MUTEX:       Locks interpreter
  76  *
  77  ******************************************************************************/
  78 acpi_status acpi_ns_evaluate(struct acpi_evaluate_info * info)
  79 {
  80         acpi_status status;
  81
  82         ACPI_FUNCTION_TRACE(ns_evaluate);
  83
  84         if (!info) {
  85                 return_ACPI_STATUS(AE_BAD_PARAMETER);
  86         }
  87
  88         /* Initialize the return value to an invalid object */
  89
  90         info->return_object = NULL;
  91
  92         /*
  93          * Get the actual namespace node for the target object. Handles these cases:
  94          *
  95          * 1) Null node, Pathname (absolute path)
  96          * 2) Node, Pathname (path relative to Node)
  97          * 3) Node, Null Pathname
  98          */
  99         status = acpi_ns_get_node(info->prefix_node, info->pathname,
 100                                   ACPI_NS_NO_UPSEARCH, &info->resolved_node);
 101         if (ACPI_FAILURE(status)) {
 102                 return_ACPI_STATUS(status);
 103         }
 104
 105         /*
 106          * For a method alias, we must grab the actual method node so that proper
 107          * scoping context will be established before execution.
 108          */
 109         if (acpi_ns_get_type(info->resolved_node) ==
 110             ACPI_TYPE_LOCAL_METHOD_ALIAS) {
 111                 info->resolved_node =
 112                     ACPI_CAST_PTR(struct acpi_namespace_node,
 113                                   info->resolved_node->object);
 114         }
 115
 116         ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "%s [%p] Value %p\n", info->pathname,
 117                           info->resolved_node,
 118                           acpi_ns_get_attached_object(info->resolved_node)));
 119
 120         /*
 121          * Two major cases here:
 122          *
 123          * 1) The object is a control method -- execute it
 124          * 2) The object is not a method -- just return it's current value
 125          */
 126         if (acpi_ns_get_type(info->resolved_node) == ACPI_TYPE_METHOD) {
 127                 /*
 128                  * 1) Object is a control method - execute it
 129                  */
 130
 131                 /* Verify that there is a method object associated with this node */
 132
 133                 info->obj_desc =
 134                     acpi_ns_get_attached_object(info->resolved_node);
 135                 if (!info->obj_desc) {
 136                         ACPI_ERROR((AE_INFO,
 137                                     "Control method has no attached sub-object"));
 138                         return_ACPI_STATUS(AE_NULL_OBJECT);
 139                 }
 140
 141                 ACPI_DUMP_PATHNAME(info->resolved_node, "Execute Method:",
 142                                    ACPI_LV_INFO, _COMPONENT);
 143
 144                 ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 145                                   "Method at AML address %p Length %X\n",
 146                                   info->obj_desc->method.aml_start + 1,
 147                                   info->obj_desc->method.aml_length - 1));
 148
 149                 /*
 150                  * Any namespace deletion must acquire both the namespace and
 151                  * interpreter locks to ensure that no thread is using the portion of
 152                  * the namespace that is being deleted.
 153                  *
 154                  * Execute the method via the interpreter. The interpreter is locked
 155                  * here before calling into the AML parser
 156                  */
 157                 acpi_ex_enter_interpreter();
 158                 status = acpi_ps_execute_method(info);
 159                 acpi_ex_exit_interpreter();
 160         } else {
 161                 /*
 162                  * 2) Object is not a method, return its current value
 163                  */
 164
 165                 /*
 166                  * Objects require additional resolution steps (e.g., the Node may be
 167                  * a field that must be read, etc.) -- we can't just grab the object
 168                  * out of the node.
 169                  *
 170                  * Use resolve_node_to_value() to get the associated value.
 171                  *
 172                  * NOTE: we can get away with passing in NULL for a walk state because
 173                  * resolved_node is guaranteed to not be a reference to either a method
 174                  * local or a method argument (because this interface is never called
 175                  * from a running method.)
 176                  *
 177                  * Even though we do not directly invoke the interpreter for object
 178                  * resolution, we must lock it because we could access an opregion.
 179                  * The opregion access code assumes that the interpreter is locked.
 180                  */
 181                 acpi_ex_enter_interpreter();
 182
 183                 /* Function has a strange interface */
 184
 185                 status =
 186                     acpi_ex_resolve_node_to_value(&info->resolved_node, NULL);
 187                 acpi_ex_exit_interpreter();
 188
 189                 /*
 190                  * If acpi_ex_resolve_node_to_value() succeeded, the return value was placed
 191                  * in resolved_node.
 192                  */
 193                 if (ACPI_SUCCESS(status)) {
 194                         status = AE_CTRL_RETURN_VALUE;
 195                         info->return_object =
 196                             ACPI_CAST_PTR(union acpi_operand_object,
 197                                           info->resolved_node);
 198
 199                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 200                                           "Returning object %p [%s]\n",
 201                                           info->return_object,
 202                                           acpi_ut_get_object_type_name(info->
 203                                                                        return_object)));
 204                 }
 205         }
 206
 207         /*
 208          * Check if there is a return value that must be dealt with
 209          */
 210         if (status == AE_CTRL_RETURN_VALUE) {
 211
 212                 /* If caller does not want the return value, delete it */
 213
 214                 if (info->flags & ACPI_IGNORE_RETURN_VALUE) {
 215                         acpi_ut_remove_reference(info->return_object);
 216                         info->return_object = NULL;
 217                 }
 218
 219                 /* Map AE_CTRL_RETURN_VALUE to AE_OK, we are done with it */
 220
 221                 status = AE_OK;
 222         }
 223
 224         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 225                           "*** Completed evaluation of object %s ***\n",
 226                           info->pathname));
 227
 228         /*
 229          * Namespace was unlocked by the handling acpi_ns* function, so we
 230          * just return
 231          */
 232         return_ACPI_STATUS(status);
 233 }