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 - 2008, Intel Corp.
   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/accommon.h>
  46 #include <acpi/acparser.h>
  47 #include <acpi/acinterp.h>
  48 #include <acpi/acnamesp.h>
  49
  50 #define _COMPONENT          ACPI_NAMESPACE
  51 ACPI_MODULE_NAME("nseval")
  52
  53 /*******************************************************************************
  54  *
  55  * FUNCTION:    acpi_ns_evaluate
  56  *
  57  * PARAMETERS:  Info            - Evaluation info block, contains:
  58  *                  prefix_node     - Prefix or Method/Object Node to execute
  59  *                  Pathname        - Name of method to execute, If NULL, the
  60  *                                    Node is the object to execute
  61  *                  Parameters      - List of parameters to pass to the method,
  62  *                                    terminated by NULL. Params itself may be
  63  *                                    NULL if no parameters are being passed.
  64  *                  return_object   - Where to put method's return value (if
  65  *                                    any). If NULL, no value is returned.
  66  *                  parameter_type  - Type of Parameter list
  67  *                  return_object   - Where to put method's return value (if
  68  *                                    any). If NULL, no value is returned.
  69  *                  Flags           - ACPI_IGNORE_RETURN_VALUE to delete return
  70  *
  71  * RETURN:      Status
  72  *
  73  * DESCRIPTION: Execute a control method or return the current value of an
  74  *              ACPI namespace object.
  75  *
  76  * MUTEX:       Locks interpreter
  77  *
  78  ******************************************************************************/
  79 acpi_status acpi_ns_evaluate(struct acpi_evaluate_info * info)
  80 {
  81         acpi_status status;
  82         struct acpi_namespace_node *node;
  83
  84         ACPI_FUNCTION_TRACE(ns_evaluate);
  85
  86         if (!info) {
  87                 return_ACPI_STATUS(AE_BAD_PARAMETER);
  88         }
  89
  90         /* Initialize the return value to an invalid object */
  91
  92         info->return_object = NULL;
  93         info->param_count = 0;
  94
  95         /*
  96          * Get the actual namespace node for the target object. Handles these cases:
  97          *
  98          * 1) Null node, Pathname (absolute path)
  99          * 2) Node, Pathname (path relative to Node)
 100          * 3) Node, Null Pathname
 101          */
 102         status = acpi_ns_get_node(info->prefix_node, info->pathname,
 103                                   ACPI_NS_NO_UPSEARCH, &info->resolved_node);
 104         if (ACPI_FAILURE(status)) {
 105                 return_ACPI_STATUS(status);
 106         }
 107
 108         /*
 109          * For a method alias, we must grab the actual method node so that proper
 110          * scoping context will be established before execution.
 111          */
 112         if (acpi_ns_get_type(info->resolved_node) ==
 113             ACPI_TYPE_LOCAL_METHOD_ALIAS) {
 114                 info->resolved_node =
 115                     ACPI_CAST_PTR(struct acpi_namespace_node,
 116                                   info->resolved_node->object);
 117         }
 118
 119         ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "%s [%p] Value %p\n", info->pathname,
 120                           info->resolved_node,
 121                           acpi_ns_get_attached_object(info->resolved_node)));
 122
 123         node = info->resolved_node;
 124
 125         /*
 126          * Two major cases here:
 127          *
 128          * 1) The object is a control method -- execute it
 129          * 2) The object is not a method -- just return it's current value
 130          */
 131         if (acpi_ns_get_type(info->resolved_node) == ACPI_TYPE_METHOD) {
 132                 /*
 133                  * 1) Object is a control method - execute it
 134                  */
 135
 136                 /* Verify that there is a method object associated with this node */
 137
 138                 info->obj_desc =
 139                     acpi_ns_get_attached_object(info->resolved_node);
 140                 if (!info->obj_desc) {
 141                         ACPI_ERROR((AE_INFO,
 142                                     "Control method has no attached sub-object"));
 143                         return_ACPI_STATUS(AE_NULL_OBJECT);
 144                 }
 145
 146                 /* Count the number of arguments being passed to the method */
 147
 148                 if (info->parameters) {
 149                         while (info->parameters[info->param_count]) {
 150                                 if (info->param_count > ACPI_METHOD_MAX_ARG) {
 151                                         return_ACPI_STATUS(AE_LIMIT);
 152                                 }
 153                                 info->param_count++;
 154                         }
 155                 }
 156
 157
 158                 ACPI_DUMP_PATHNAME(info->resolved_node, "Execute Method:",
 159                                    ACPI_LV_INFO, _COMPONENT);
 160
 161                 ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 162                                   "Method at AML address %p Length %X\n",
 163                                   info->obj_desc->method.aml_start + 1,
 164                                   info->obj_desc->method.aml_length - 1));
 165
 166                 /*
 167                  * Any namespace deletion must acquire both the namespace and
 168                  * interpreter locks to ensure that no thread is using the portion of
 169                  * the namespace that is being deleted.
 170                  *
 171                  * Execute the method via the interpreter. The interpreter is locked
 172                  * here before calling into the AML parser
 173                  */
 174                 acpi_ex_enter_interpreter();
 175                 status = acpi_ps_execute_method(info);
 176                 acpi_ex_exit_interpreter();
 177         } else {
 178                 /*
 179                  * 2) Object is not a method, return its current value
 180                  *
 181                  * Disallow certain object types. For these, "evaluation" is undefined.
 182                  */
 183                 switch (info->resolved_node->type) {
 184                 case ACPI_TYPE_DEVICE:
 185                 case ACPI_TYPE_EVENT:
 186                 case ACPI_TYPE_MUTEX:
 187                 case ACPI_TYPE_REGION:
 188                 case ACPI_TYPE_THERMAL:
 189                 case ACPI_TYPE_LOCAL_SCOPE:
 190
 191                         ACPI_ERROR((AE_INFO,
 192                                     "[%4.4s] Evaluation of object type [%s] is not supported",
 193                                     info->resolved_node->name.ascii,
 194                                     acpi_ut_get_type_name(info->resolved_node->
 195                                                           type)));
 196
 197                         return_ACPI_STATUS(AE_TYPE);
 198
 199                 default:
 200                         break;
 201                 }
 202
 203                 /*
 204                  * Objects require additional resolution steps (e.g., the Node may be
 205                  * a field that must be read, etc.) -- we can't just grab the object
 206                  * out of the node.
 207                  *
 208                  * Use resolve_node_to_value() to get the associated value.
 209                  *
 210                  * NOTE: we can get away with passing in NULL for a walk state because
 211                  * resolved_node is guaranteed to not be a reference to either a method
 212                  * local or a method argument (because this interface is never called
 213                  * from a running method.)
 214                  *
 215                  * Even though we do not directly invoke the interpreter for object
 216                  * resolution, we must lock it because we could access an opregion.
 217                  * The opregion access code assumes that the interpreter is locked.
 218                  */
 219                 acpi_ex_enter_interpreter();
 220
 221                 /* Function has a strange interface */
 222
 223                 status =
 224                     acpi_ex_resolve_node_to_value(&info->resolved_node, NULL);
 225                 acpi_ex_exit_interpreter();
 226
 227                 /*
 228                  * If acpi_ex_resolve_node_to_value() succeeded, the return value was placed
 229                  * in resolved_node.
 230                  */
 231                 if (ACPI_SUCCESS(status)) {
 232                         status = AE_CTRL_RETURN_VALUE;
 233                         info->return_object =
 234                             ACPI_CAST_PTR(union acpi_operand_object,
 235                                           info->resolved_node);
 236
 237                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 238                                           "Returning object %p [%s]\n",
 239                                           info->return_object,
 240                                           acpi_ut_get_object_type_name(info->
 241                                                                        return_object)));
 242                 }
 243         }
 244
 245         /*
 246          * Check input argument count against the ASL-defined count for a method.
 247          * Also check predefined names: argument count and return value against
 248          * the ACPI specification. Some incorrect return value types are repaired.
 249          */
 250         (void)acpi_ns_check_predefined_names(node, info->param_count,
 251                 status, &info->return_object);
 252
 253         /* Check if there is a return value that must be dealt with */
 254
 255         if (status == AE_CTRL_RETURN_VALUE) {
 256
 257                 /* If caller does not want the return value, delete it */
 258
 259                 if (info->flags & ACPI_IGNORE_RETURN_VALUE) {
 260                         acpi_ut_remove_reference(info->return_object);
 261                         info->return_object = NULL;
 262                 }
 263
 264                 /* Map AE_CTRL_RETURN_VALUE to AE_OK, we are done with it */
 265
 266                 status = AE_OK;
 267         }
 268
 269         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 270                           "*** Completed evaluation of object %s ***\n",
 271                           info->pathname));
 272
 273         /*
 274          * Namespace was unlocked by the handling acpi_ns* function, so we
 275          * just return
 276          */
 277         return_ACPI_STATUS(status);
 278 }