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  1. /******************************************************************************
  2.  *
  3.  * Module Name: dswstate - Dispatcher parse tree walk management routines
  4.  *
  5.  *****************************************************************************/
  6.  
  7. /*
  8.  * Copyright (C) 2000 - 2015, 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 "accommon.h"
  46. #include "acparser.h"
  47. #include "acdispat.h"
  48. #include "acnamesp.h"
  49.  
  50. #define _COMPONENT          ACPI_DISPATCHER
  51. ACPI_MODULE_NAME("dswstate")
  52.  
  53.   /* Local prototypes */
  54. static acpi_status
  55. acpi_ds_result_stack_push(struct acpi_walk_state *walk_state);
  56. static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state);
  57.  
  58. /*******************************************************************************
  59.  *
  60.  * FUNCTION:    acpi_ds_result_pop
  61.  *
  62.  * PARAMETERS:  object              - Where to return the popped object
  63.  *              walk_state          - Current Walk state
  64.  *
  65.  * RETURN:      Status
  66.  *
  67.  * DESCRIPTION: Pop an object off the top of this walk's result stack
  68.  *
  69.  ******************************************************************************/
  70.  
  71. acpi_status
  72. acpi_ds_result_pop(union acpi_operand_object **object,
  73.                    struct acpi_walk_state *walk_state)
  74. {
  75.         u32 index;
  76.         union acpi_generic_state *state;
  77.         acpi_status status;
  78.  
  79.         ACPI_FUNCTION_NAME(ds_result_pop);
  80.  
  81.         state = walk_state->results;
  82.  
  83.         /* Incorrect state of result stack */
  84.  
  85.         if (state && !walk_state->result_count) {
  86.                 ACPI_ERROR((AE_INFO, "No results on result stack"));
  87.                 return (AE_AML_INTERNAL);
  88.         }
  89.  
  90.         if (!state && walk_state->result_count) {
  91.                 ACPI_ERROR((AE_INFO, "No result state for result stack"));
  92.                 return (AE_AML_INTERNAL);
  93.         }
  94.  
  95.         /* Empty result stack */
  96.  
  97.         if (!state) {
  98.                 ACPI_ERROR((AE_INFO, "Result stack is empty! State=%p",
  99.                             walk_state));
  100.                 return (AE_AML_NO_RETURN_VALUE);
  101.         }
  102.  
  103.         /* Return object of the top element and clean that top element result stack */
  104.  
  105.         walk_state->result_count--;
  106.         index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
  107.  
  108.         *object = state->results.obj_desc[index];
  109.         if (!*object) {
  110.                 ACPI_ERROR((AE_INFO,
  111.                             "No result objects on result stack, State=%p",
  112.                             walk_state));
  113.                 return (AE_AML_NO_RETURN_VALUE);
  114.         }
  115.  
  116.         state->results.obj_desc[index] = NULL;
  117.         if (index == 0) {
  118.                 status = acpi_ds_result_stack_pop(walk_state);
  119.                 if (ACPI_FAILURE(status)) {
  120.                         return (status);
  121.                 }
  122.         }
  123.  
  124.         ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
  125.                           "Obj=%p [%s] Index=%X State=%p Num=%X\n", *object,
  126.                           acpi_ut_get_object_type_name(*object),
  127.                           index, walk_state, walk_state->result_count));
  128.  
  129.         return (AE_OK);
  130. }
  131.  
  132. /*******************************************************************************
  133.  *
  134.  * FUNCTION:    acpi_ds_result_push
  135.  *
  136.  * PARAMETERS:  object              - Where to return the popped object
  137.  *              walk_state          - Current Walk state
  138.  *
  139.  * RETURN:      Status
  140.  *
  141.  * DESCRIPTION: Push an object onto the current result stack
  142.  *
  143.  ******************************************************************************/
  144.  
  145. acpi_status
  146. acpi_ds_result_push(union acpi_operand_object * object,
  147.                     struct acpi_walk_state * walk_state)
  148. {
  149.         union acpi_generic_state *state;
  150.         acpi_status status;
  151.         u32 index;
  152.  
  153.         ACPI_FUNCTION_NAME(ds_result_push);
  154.  
  155.         if (walk_state->result_count > walk_state->result_size) {
  156.                 ACPI_ERROR((AE_INFO, "Result stack is full"));
  157.                 return (AE_AML_INTERNAL);
  158.         } else if (walk_state->result_count == walk_state->result_size) {
  159.  
  160.                 /* Extend the result stack */
  161.  
  162.                 status = acpi_ds_result_stack_push(walk_state);
  163.                 if (ACPI_FAILURE(status)) {
  164.                         ACPI_ERROR((AE_INFO,
  165.                                     "Failed to extend the result stack"));
  166.                         return (status);
  167.                 }
  168.         }
  169.  
  170.         if (!(walk_state->result_count < walk_state->result_size)) {
  171.                 ACPI_ERROR((AE_INFO, "No free elements in result stack"));
  172.                 return (AE_AML_INTERNAL);
  173.         }
  174.  
  175.         state = walk_state->results;
  176.         if (!state) {
  177.                 ACPI_ERROR((AE_INFO, "No result stack frame during push"));
  178.                 return (AE_AML_INTERNAL);
  179.         }
  180.  
  181.         if (!object) {
  182.                 ACPI_ERROR((AE_INFO,
  183.                             "Null Object! Obj=%p State=%p Num=%u",
  184.                             object, walk_state, walk_state->result_count));
  185.                 return (AE_BAD_PARAMETER);
  186.         }
  187.  
  188.         /* Assign the address of object to the top free element of result stack */
  189.  
  190.         index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
  191.         state->results.obj_desc[index] = object;
  192.         walk_state->result_count++;
  193.  
  194.         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p Num=%X Cur=%X\n",
  195.                           object,
  196.                           acpi_ut_get_object_type_name((union
  197.                                                         acpi_operand_object *)
  198.                                                        object), walk_state,
  199.                           walk_state->result_count,
  200.                           walk_state->current_result));
  201.  
  202.         return (AE_OK);
  203. }
  204.  
  205. /*******************************************************************************
  206.  *
  207.  * FUNCTION:    acpi_ds_result_stack_push
  208.  *
  209.  * PARAMETERS:  walk_state          - Current Walk state
  210.  *
  211.  * RETURN:      Status
  212.  *
  213.  * DESCRIPTION: Push an object onto the walk_state result stack
  214.  *
  215.  ******************************************************************************/
  216.  
  217. static acpi_status acpi_ds_result_stack_push(struct acpi_walk_state *walk_state)
  218. {
  219.         union acpi_generic_state *state;
  220.  
  221.         ACPI_FUNCTION_NAME(ds_result_stack_push);
  222.  
  223.         /* Check for stack overflow */
  224.  
  225.         if (((u32) walk_state->result_size + ACPI_RESULTS_FRAME_OBJ_NUM) >
  226.             ACPI_RESULTS_OBJ_NUM_MAX) {
  227.                 ACPI_ERROR((AE_INFO, "Result stack overflow: State=%p Num=%u",
  228.                             walk_state, walk_state->result_size));
  229.                 return (AE_STACK_OVERFLOW);
  230.         }
  231.  
  232.         state = acpi_ut_create_generic_state();
  233.         if (!state) {
  234.                 return (AE_NO_MEMORY);
  235.         }
  236.  
  237.         state->common.descriptor_type = ACPI_DESC_TYPE_STATE_RESULT;
  238.         acpi_ut_push_generic_state(&walk_state->results, state);
  239.  
  240.         /* Increase the length of the result stack by the length of frame */
  241.  
  242.         walk_state->result_size += ACPI_RESULTS_FRAME_OBJ_NUM;
  243.  
  244.         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Results=%p State=%p\n",
  245.                           state, walk_state));
  246.  
  247.         return (AE_OK);
  248. }
  249.  
  250. /*******************************************************************************
  251.  *
  252.  * FUNCTION:    acpi_ds_result_stack_pop
  253.  *
  254.  * PARAMETERS:  walk_state          - Current Walk state
  255.  *
  256.  * RETURN:      Status
  257.  *
  258.  * DESCRIPTION: Pop an object off of the walk_state result stack
  259.  *
  260.  ******************************************************************************/
  261.  
  262. static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state)
  263. {
  264.         union acpi_generic_state *state;
  265.  
  266.         ACPI_FUNCTION_NAME(ds_result_stack_pop);
  267.  
  268.         /* Check for stack underflow */
  269.  
  270.         if (walk_state->results == NULL) {
  271.                 ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
  272.                                   "Result stack underflow - State=%p\n",
  273.                                   walk_state));
  274.                 return (AE_AML_NO_OPERAND);
  275.         }
  276.  
  277.         if (walk_state->result_size < ACPI_RESULTS_FRAME_OBJ_NUM) {
  278.                 ACPI_ERROR((AE_INFO, "Insufficient result stack size"));
  279.                 return (AE_AML_INTERNAL);
  280.         }
  281.  
  282.         state = acpi_ut_pop_generic_state(&walk_state->results);
  283.         acpi_ut_delete_generic_state(state);
  284.  
  285.         /* Decrease the length of result stack by the length of frame */
  286.  
  287.         walk_state->result_size -= ACPI_RESULTS_FRAME_OBJ_NUM;
  288.  
  289.         ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
  290.                           "Result=%p RemainingResults=%X State=%p\n",
  291.                           state, walk_state->result_count, walk_state));
  292.  
  293.         return (AE_OK);
  294. }
  295.  
  296. /*******************************************************************************
  297.  *
  298.  * FUNCTION:    acpi_ds_obj_stack_push
  299.  *
  300.  * PARAMETERS:  object              - Object to push
  301.  *              walk_state          - Current Walk state
  302.  *
  303.  * RETURN:      Status
  304.  *
  305.  * DESCRIPTION: Push an object onto this walk's object/operand stack
  306.  *
  307.  ******************************************************************************/
  308.  
  309. acpi_status
  310. acpi_ds_obj_stack_push(void *object, struct acpi_walk_state * walk_state)
  311. {
  312.         ACPI_FUNCTION_NAME(ds_obj_stack_push);
  313.  
  314.         /* Check for stack overflow */
  315.  
  316.         if (walk_state->num_operands >= ACPI_OBJ_NUM_OPERANDS) {
  317.                 ACPI_ERROR((AE_INFO,
  318.                             "Object stack overflow! Obj=%p State=%p #Ops=%u",
  319.                             object, walk_state, walk_state->num_operands));
  320.                 return (AE_STACK_OVERFLOW);
  321.         }
  322.  
  323.         /* Put the object onto the stack */
  324.  
  325.         walk_state->operands[walk_state->operand_index] = object;
  326.         walk_state->num_operands++;
  327.  
  328.         /* For the usual order of filling the operand stack */
  329.  
  330.         walk_state->operand_index++;
  331.  
  332.         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p #Ops=%X\n",
  333.                           object,
  334.                           acpi_ut_get_object_type_name((union
  335.                                                         acpi_operand_object *)
  336.                                                        object), walk_state,
  337.                           walk_state->num_operands));
  338.  
  339.         return (AE_OK);
  340. }
  341.  
  342. /*******************************************************************************
  343.  *
  344.  * FUNCTION:    acpi_ds_obj_stack_pop
  345.  *
  346.  * PARAMETERS:  pop_count           - Number of objects/entries to pop
  347.  *              walk_state          - Current Walk state
  348.  *
  349.  * RETURN:      Status
  350.  *
  351.  * DESCRIPTION: Pop this walk's object stack. Objects on the stack are NOT
  352.  *              deleted by this routine.
  353.  *
  354.  ******************************************************************************/
  355.  
  356. acpi_status
  357. acpi_ds_obj_stack_pop(u32 pop_count, struct acpi_walk_state * walk_state)
  358. {
  359.         u32 i;
  360.  
  361.         ACPI_FUNCTION_NAME(ds_obj_stack_pop);
  362.  
  363.         for (i = 0; i < pop_count; i++) {
  364.  
  365.                 /* Check for stack underflow */
  366.  
  367.                 if (walk_state->num_operands == 0) {
  368.                         ACPI_ERROR((AE_INFO,
  369.                                     "Object stack underflow! Count=%X State=%p #Ops=%u",
  370.                                     pop_count, walk_state,
  371.                                     walk_state->num_operands));
  372.                         return (AE_STACK_UNDERFLOW);
  373.                 }
  374.  
  375.                 /* Just set the stack entry to null */
  376.  
  377.                 walk_state->num_operands--;
  378.                 walk_state->operands[walk_state->num_operands] = NULL;
  379.         }
  380.  
  381.         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%u\n",
  382.                           pop_count, walk_state, walk_state->num_operands));
  383.  
  384.         return (AE_OK);
  385. }
  386.  
  387. /*******************************************************************************
  388.  *
  389.  * FUNCTION:    acpi_ds_obj_stack_pop_and_delete
  390.  *
  391.  * PARAMETERS:  pop_count           - Number of objects/entries to pop
  392.  *              walk_state          - Current Walk state
  393.  *
  394.  * RETURN:      Status
  395.  *
  396.  * DESCRIPTION: Pop this walk's object stack and delete each object that is
  397.  *              popped off.
  398.  *
  399.  ******************************************************************************/
  400.  
  401. void
  402. acpi_ds_obj_stack_pop_and_delete(u32 pop_count,
  403.                                  struct acpi_walk_state *walk_state)
  404. {
  405.         s32 i;
  406.         union acpi_operand_object *obj_desc;
  407.  
  408.         ACPI_FUNCTION_NAME(ds_obj_stack_pop_and_delete);
  409.  
  410.         if (pop_count == 0) {
  411.                 return;
  412.         }
  413.  
  414.         for (i = (s32) pop_count - 1; i >= 0; i--) {
  415.                 if (walk_state->num_operands == 0) {
  416.                         return;
  417.                 }
  418.  
  419.                 /* Pop the stack and delete an object if present in this stack entry */
  420.  
  421.                 walk_state->num_operands--;
  422.                 obj_desc = walk_state->operands[i];
  423.                 if (obj_desc) {
  424.                         acpi_ut_remove_reference(walk_state->operands[i]);
  425.                         walk_state->operands[i] = NULL;
  426.                 }
  427.         }
  428.  
  429.         ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%X\n",
  430.                           pop_count, walk_state, walk_state->num_operands));
  431. }
  432.  
  433. /*******************************************************************************
  434.  *
  435.  * FUNCTION:    acpi_ds_get_current_walk_state
  436.  *
  437.  * PARAMETERS:  thread          - Get current active state for this Thread
  438.  *
  439.  * RETURN:      Pointer to the current walk state
  440.  *
  441.  * DESCRIPTION: Get the walk state that is at the head of the list (the "current"
  442.  *              walk state.)
  443.  *
  444.  ******************************************************************************/
  445.  
  446. struct acpi_walk_state *acpi_ds_get_current_walk_state(struct acpi_thread_state
  447.                                                        *thread)
  448. {
  449.         ACPI_FUNCTION_NAME(ds_get_current_walk_state);
  450.  
  451.         if (!thread) {
  452.                 return (NULL);
  453.         }
  454.  
  455.         ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "Current WalkState %p\n",
  456.                           thread->walk_state_list));
  457.  
  458.         return (thread->walk_state_list);
  459. }
  460.  
  461. /*******************************************************************************
  462.  *
  463.  * FUNCTION:    acpi_ds_push_walk_state
  464.  *
  465.  * PARAMETERS:  walk_state      - State to push
  466.  *              thread          - Thread state object
  467.  *
  468.  * RETURN:      None
  469.  *
  470.  * DESCRIPTION: Place the Thread state at the head of the state list
  471.  *
  472.  ******************************************************************************/
  473.  
  474. void
  475. acpi_ds_push_walk_state(struct acpi_walk_state *walk_state,
  476.                         struct acpi_thread_state *thread)
  477. {
  478.         ACPI_FUNCTION_TRACE(ds_push_walk_state);
  479.  
  480.         walk_state->next = thread->walk_state_list;
  481.         thread->walk_state_list = walk_state;
  482.  
  483.         return_VOID;
  484. }
  485.  
  486. /*******************************************************************************
  487.  *
  488.  * FUNCTION:    acpi_ds_pop_walk_state
  489.  *
  490.  * PARAMETERS:  thread      - Current thread state
  491.  *
  492.  * RETURN:      A walk_state object popped from the thread's stack
  493.  *
  494.  * DESCRIPTION: Remove and return the walkstate object that is at the head of
  495.  *              the walk stack for the given walk list. NULL indicates that
  496.  *              the list is empty.
  497.  *
  498.  ******************************************************************************/
  499.  
  500. struct acpi_walk_state *acpi_ds_pop_walk_state(struct acpi_thread_state *thread)
  501. {
  502.         struct acpi_walk_state *walk_state;
  503.  
  504.         ACPI_FUNCTION_TRACE(ds_pop_walk_state);
  505.  
  506.         walk_state = thread->walk_state_list;
  507.  
  508.         if (walk_state) {
  509.  
  510.                 /* Next walk state becomes the current walk state */
  511.  
  512.                 thread->walk_state_list = walk_state->next;
  513.  
  514.                 /*
  515.                  * Don't clear the NEXT field, this serves as an indicator
  516.                  * that there is a parent WALK STATE
  517.                  * Do Not: walk_state->Next = NULL;
  518.                  */
  519.         }
  520.  
  521.         return_PTR(walk_state);
  522. }
  523.  
  524. /*******************************************************************************
  525.  *
  526.  * FUNCTION:    acpi_ds_create_walk_state
  527.  *
  528.  * PARAMETERS:  owner_id        - ID for object creation
  529.  *              origin          - Starting point for this walk
  530.  *              method_desc     - Method object
  531.  *              thread          - Current thread state
  532.  *
  533.  * RETURN:      Pointer to the new walk state.
  534.  *
  535.  * DESCRIPTION: Allocate and initialize a new walk state. The current walk
  536.  *              state is set to this new state.
  537.  *
  538.  ******************************************************************************/
  539.  
  540. struct acpi_walk_state *acpi_ds_create_walk_state(acpi_owner_id owner_id,
  541.                                                   union acpi_parse_object
  542.                                                   *origin,
  543.                                                   union acpi_operand_object
  544.                                                   *method_desc,
  545.                                                   struct acpi_thread_state
  546.                                                   *thread)
  547. {
  548.         struct acpi_walk_state *walk_state;
  549.  
  550.         ACPI_FUNCTION_TRACE(ds_create_walk_state);
  551.  
  552.         walk_state = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_walk_state));
  553.         if (!walk_state) {
  554.                 return_PTR(NULL);
  555.         }
  556.  
  557.         walk_state->descriptor_type = ACPI_DESC_TYPE_WALK;
  558.         walk_state->method_desc = method_desc;
  559.         walk_state->owner_id = owner_id;
  560.         walk_state->origin = origin;
  561.         walk_state->thread = thread;
  562.  
  563.         walk_state->parser_state.start_op = origin;
  564.  
  565.         /* Init the method args/local */
  566.  
  567. #if (!defined (ACPI_NO_METHOD_EXECUTION) && !defined (ACPI_CONSTANT_EVAL_ONLY))
  568.         acpi_ds_method_data_init(walk_state);
  569. #endif
  570.  
  571.         /* Put the new state at the head of the walk list */
  572.  
  573.         if (thread) {
  574.                 acpi_ds_push_walk_state(walk_state, thread);
  575.         }
  576.  
  577.         return_PTR(walk_state);
  578. }
  579.  
  580. /*******************************************************************************
  581.  *
  582.  * FUNCTION:    acpi_ds_init_aml_walk
  583.  *
  584.  * PARAMETERS:  walk_state      - New state to be initialized
  585.  *              op              - Current parse op
  586.  *              method_node     - Control method NS node, if any
  587.  *              aml_start       - Start of AML
  588.  *              aml_length      - Length of AML
  589.  *              info            - Method info block (params, etc.)
  590.  *              pass_number     - 1, 2, or 3
  591.  *
  592.  * RETURN:      Status
  593.  *
  594.  * DESCRIPTION: Initialize a walk state for a pass 1 or 2 parse tree walk
  595.  *
  596.  ******************************************************************************/
  597.  
  598. acpi_status
  599. acpi_ds_init_aml_walk(struct acpi_walk_state *walk_state,
  600.                       union acpi_parse_object *op,
  601.                       struct acpi_namespace_node *method_node,
  602.                       u8 * aml_start,
  603.                       u32 aml_length,
  604.                       struct acpi_evaluate_info *info, u8 pass_number)
  605. {
  606.         acpi_status status;
  607.         struct acpi_parse_state *parser_state = &walk_state->parser_state;
  608.         union acpi_parse_object *extra_op;
  609.  
  610.         ACPI_FUNCTION_TRACE(ds_init_aml_walk);
  611.  
  612.         walk_state->parser_state.aml =
  613.             walk_state->parser_state.aml_start = aml_start;
  614.         walk_state->parser_state.aml_end =
  615.             walk_state->parser_state.pkg_end = aml_start + aml_length;
  616.  
  617.         /* The next_op of the next_walk will be the beginning of the method */
  618.  
  619.         walk_state->next_op = NULL;
  620.         walk_state->pass_number = pass_number;
  621.  
  622.         if (info) {
  623.                 walk_state->params = info->parameters;
  624.                 walk_state->caller_return_desc = &info->return_object;
  625.         }
  626.  
  627.         status = acpi_ps_init_scope(&walk_state->parser_state, op);
  628.         if (ACPI_FAILURE(status)) {
  629.                 return_ACPI_STATUS(status);
  630.         }
  631.  
  632.         if (method_node) {
  633.                 walk_state->parser_state.start_node = method_node;
  634.                 walk_state->walk_type = ACPI_WALK_METHOD;
  635.                 walk_state->method_node = method_node;
  636.                 walk_state->method_desc =
  637.                     acpi_ns_get_attached_object(method_node);
  638.  
  639.                 /* Push start scope on scope stack and make it current  */
  640.  
  641.                 status =
  642.                     acpi_ds_scope_stack_push(method_node, ACPI_TYPE_METHOD,
  643.                                              walk_state);
  644.                 if (ACPI_FAILURE(status)) {
  645.                         return_ACPI_STATUS(status);
  646.                 }
  647.  
  648.                 /* Init the method arguments */
  649.  
  650.                 status = acpi_ds_method_data_init_args(walk_state->params,
  651.                                                        ACPI_METHOD_NUM_ARGS,
  652.                                                        walk_state);
  653.                 if (ACPI_FAILURE(status)) {
  654.                         return_ACPI_STATUS(status);
  655.                 }
  656.         } else {
  657.                 /*
  658.                  * Setup the current scope.
  659.                  * Find a Named Op that has a namespace node associated with it.
  660.                  * search upwards from this Op. Current scope is the first
  661.                  * Op with a namespace node.
  662.                  */
  663.                 extra_op = parser_state->start_op;
  664.                 while (extra_op && !extra_op->common.node) {
  665.                         extra_op = extra_op->common.parent;
  666.                 }
  667.  
  668.                 if (!extra_op) {
  669.                         parser_state->start_node = NULL;
  670.                 } else {
  671.                         parser_state->start_node = extra_op->common.node;
  672.                 }
  673.  
  674.                 if (parser_state->start_node) {
  675.  
  676.                         /* Push start scope on scope stack and make it current  */
  677.  
  678.                         status =
  679.                             acpi_ds_scope_stack_push(parser_state->start_node,
  680.                                                      parser_state->start_node->
  681.                                                      type, walk_state);
  682.                         if (ACPI_FAILURE(status)) {
  683.                                 return_ACPI_STATUS(status);
  684.                         }
  685.                 }
  686.         }
  687.  
  688.         status = acpi_ds_init_callbacks(walk_state, pass_number);
  689.         return_ACPI_STATUS(status);
  690. }
  691.  
  692. /*******************************************************************************
  693.  *
  694.  * FUNCTION:    acpi_ds_delete_walk_state
  695.  *
  696.  * PARAMETERS:  walk_state      - State to delete
  697.  *
  698.  * RETURN:      Status
  699.  *
  700.  * DESCRIPTION: Delete a walk state including all internal data structures
  701.  *
  702.  ******************************************************************************/
  703.  
  704. void acpi_ds_delete_walk_state(struct acpi_walk_state *walk_state)
  705. {
  706.         union acpi_generic_state *state;
  707.  
  708.         ACPI_FUNCTION_TRACE_PTR(ds_delete_walk_state, walk_state);
  709.  
  710.         if (!walk_state) {
  711.                 return_VOID;
  712.         }
  713.  
  714.         if (walk_state->descriptor_type != ACPI_DESC_TYPE_WALK) {
  715.                 ACPI_ERROR((AE_INFO, "%p is not a valid walk state",
  716.                             walk_state));
  717.                 return_VOID;
  718.         }
  719.  
  720.         /* There should not be any open scopes */
  721.  
  722.         if (walk_state->parser_state.scope) {
  723.                 ACPI_ERROR((AE_INFO, "%p walk still has a scope list",
  724.                             walk_state));
  725.                 acpi_ps_cleanup_scope(&walk_state->parser_state);
  726.         }
  727.  
  728.         /* Always must free any linked control states */
  729.  
  730.         while (walk_state->control_state) {
  731.                 state = walk_state->control_state;
  732.                 walk_state->control_state = state->common.next;
  733.  
  734.                 acpi_ut_delete_generic_state(state);
  735.         }
  736.  
  737.         /* Always must free any linked parse states */
  738.  
  739.         while (walk_state->scope_info) {
  740.                 state = walk_state->scope_info;
  741.                 walk_state->scope_info = state->common.next;
  742.  
  743.                 acpi_ut_delete_generic_state(state);
  744.         }
  745.  
  746.         /* Always must free any stacked result states */
  747.  
  748.         while (walk_state->results) {
  749.                 state = walk_state->results;
  750.                 walk_state->results = state->common.next;
  751.  
  752.                 acpi_ut_delete_generic_state(state);
  753.         }
  754.  
  755.         ACPI_FREE(walk_state);
  756.         return_VOID;
  757. }
  758.