// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: dswstate - Dispatcher parse tree walk management routines
 *
 * Copyright (C) 2000 - 2025, Intel Corp.
 *
 *****************************************************************************/

#include <acpi/acpi.h>
#include "accommon.h"
#include "acparser.h"
#include "acdispat.h"
#include "acnamesp.h"

#define _COMPONENT          ACPI_DISPATCHER
ACPI_MODULE_NAME("dswstate")

  /* Local prototypes */
static acpi_status
acpi_ds_result_stack_push(struct acpi_walk_state *walk_state);
static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_result_pop
 *
 * PARAMETERS:  object              - Where to return the popped object
 *              walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Pop an object off the top of this walk's result stack
 *
 ******************************************************************************/

acpi_status
acpi_ds_result_pop(union acpi_operand_object **object,
                   struct acpi_walk_state *walk_state)
{
        u32 index;
        union acpi_generic_state *state;
        acpi_status status;

        ACPI_FUNCTION_NAME(ds_result_pop);

        state = walk_state->results;

        /* Incorrect state of result stack */

        if (state && !walk_state->result_count) {
                ACPI_ERROR((AE_INFO, "No results on result stack"));
                return (AE_AML_INTERNAL);
        }

        if (!state && walk_state->result_count) {
                ACPI_ERROR((AE_INFO, "No result state for result stack"));
                return (AE_AML_INTERNAL);
        }

        /* Empty result stack */

        if (!state) {
                ACPI_ERROR((AE_INFO, "Result stack is empty! State=%p",
                            walk_state));
                return (AE_AML_NO_RETURN_VALUE);
        }

        /* Return object of the top element and clean that top element result stack */

        walk_state->result_count--;
        index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;

        *object = state->results.obj_desc[index];
        if (!*object) {
                ACPI_ERROR((AE_INFO,
                            "No result objects on result stack, State=%p",
                            walk_state));
                return (AE_AML_NO_RETURN_VALUE);
        }

        state->results.obj_desc[index] = NULL;
        if (index == 0) {
                status = acpi_ds_result_stack_pop(walk_state);
                if (ACPI_FAILURE(status)) {
                        return (status);
                }
        }

        ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
                          "Obj=%p [%s] Index=%X State=%p Num=%X\n", *object,
                          acpi_ut_get_object_type_name(*object),
                          index, walk_state, walk_state->result_count));

        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_result_push
 *
 * PARAMETERS:  object              - Where to return the popped object
 *              walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Push an object onto the current result stack
 *
 ******************************************************************************/

acpi_status
acpi_ds_result_push(union acpi_operand_object *object,
                    struct acpi_walk_state *walk_state)
{
        union acpi_generic_state *state;
        acpi_status status;
        u32 index;

        ACPI_FUNCTION_NAME(ds_result_push);

        if (walk_state->result_count > walk_state->result_size) {
                ACPI_ERROR((AE_INFO, "Result stack is full"));
                return (AE_AML_INTERNAL);
        } else if (walk_state->result_count == walk_state->result_size) {

                /* Extend the result stack */

                status = acpi_ds_result_stack_push(walk_state);
                if (ACPI_FAILURE(status)) {
                        ACPI_ERROR((AE_INFO,
                                    "Failed to extend the result stack"));
                        return (status);
                }
        }

        if (!(walk_state->result_count < walk_state->result_size)) {
                ACPI_ERROR((AE_INFO, "No free elements in result stack"));
                return (AE_AML_INTERNAL);
        }

        state = walk_state->results;
        if (!state) {
                ACPI_ERROR((AE_INFO, "No result stack frame during push"));
                return (AE_AML_INTERNAL);
        }

        if (!object) {
                ACPI_ERROR((AE_INFO,
                            "Null Object! State=%p Num=%u",
                            walk_state, walk_state->result_count));
                return (AE_BAD_PARAMETER);
        }

        /* Assign the address of object to the top free element of result stack */

        index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
        state->results.obj_desc[index] = object;
        walk_state->result_count++;

        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p Num=%X Cur=%X\n",
                          object,
                          acpi_ut_get_object_type_name((union
                                                        acpi_operand_object *)
                                                       object), walk_state,
                          walk_state->result_count,
                          walk_state->current_result));

        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_result_stack_push
 *
 * PARAMETERS:  walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Push an object onto the walk_state result stack
 *
 ******************************************************************************/

static acpi_status acpi_ds_result_stack_push(struct acpi_walk_state *walk_state)
{
        union acpi_generic_state *state;

        ACPI_FUNCTION_NAME(ds_result_stack_push);

        /* Check for stack overflow */

        if (((u32) walk_state->result_size + ACPI_RESULTS_FRAME_OBJ_NUM) >
            ACPI_RESULTS_OBJ_NUM_MAX) {
                ACPI_ERROR((AE_INFO, "Result stack overflow: State=%p Num=%u",
                            walk_state, walk_state->result_size));
                return (AE_STACK_OVERFLOW);
        }

        state = acpi_ut_create_generic_state();
        if (!state) {
                return (AE_NO_MEMORY);
        }

        state->common.descriptor_type = ACPI_DESC_TYPE_STATE_RESULT;
        acpi_ut_push_generic_state(&walk_state->results, state);

        /* Increase the length of the result stack by the length of frame */

        walk_state->result_size += ACPI_RESULTS_FRAME_OBJ_NUM;

        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Results=%p State=%p\n",
                          state, walk_state));

        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_result_stack_pop
 *
 * PARAMETERS:  walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Pop an object off of the walk_state result stack
 *
 ******************************************************************************/

static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state)
{
        union acpi_generic_state *state;

        ACPI_FUNCTION_NAME(ds_result_stack_pop);

        /* Check for stack underflow */

        if (walk_state->results == NULL) {
                ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
                                  "Result stack underflow - State=%p\n",
                                  walk_state));
                return (AE_AML_NO_OPERAND);
        }

        if (walk_state->result_size < ACPI_RESULTS_FRAME_OBJ_NUM) {
                ACPI_ERROR((AE_INFO, "Insufficient result stack size"));
                return (AE_AML_INTERNAL);
        }

        state = acpi_ut_pop_generic_state(&walk_state->results);
        acpi_ut_delete_generic_state(state);

        /* Decrease the length of result stack by the length of frame */

        walk_state->result_size -= ACPI_RESULTS_FRAME_OBJ_NUM;

        ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
                          "Result=%p RemainingResults=%X State=%p\n",
                          state, walk_state->result_count, walk_state));

        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_obj_stack_push
 *
 * PARAMETERS:  object              - Object to push
 *              walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Push an object onto this walk's object/operand stack
 *
 ******************************************************************************/

acpi_status
acpi_ds_obj_stack_push(void *object, struct acpi_walk_state *walk_state)
{
        ACPI_FUNCTION_NAME(ds_obj_stack_push);

        /* Check for stack overflow */

        if (walk_state->num_operands >= ACPI_OBJ_NUM_OPERANDS) {
                ACPI_ERROR((AE_INFO,
                            "Object stack overflow! Obj=%p State=%p #Ops=%u",
                            object, walk_state, walk_state->num_operands));
                return (AE_STACK_OVERFLOW);
        }

        /* Put the object onto the stack */

        walk_state->operands[walk_state->operand_index] = object;
        walk_state->num_operands++;

        /* For the usual order of filling the operand stack */

        walk_state->operand_index++;

        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p #Ops=%X\n",
                          object,
                          acpi_ut_get_object_type_name((union
                                                        acpi_operand_object *)
                                                       object), walk_state,
                          walk_state->num_operands));

        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_obj_stack_pop
 *
 * PARAMETERS:  pop_count           - Number of objects/entries to pop
 *              walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Pop this walk's object stack. Objects on the stack are NOT
 *              deleted by this routine.
 *
 ******************************************************************************/

acpi_status
acpi_ds_obj_stack_pop(u32 pop_count, struct acpi_walk_state *walk_state)
{
        u32 i;

        ACPI_FUNCTION_NAME(ds_obj_stack_pop);

        for (i = 0; i < pop_count; i++) {

                /* Check for stack underflow */

                if (walk_state->num_operands == 0) {
                        ACPI_ERROR((AE_INFO,
                                    "Object stack underflow! Count=%X State=%p #Ops=%u",
                                    pop_count, walk_state,
                                    walk_state->num_operands));
                        return (AE_STACK_UNDERFLOW);
                }

                /* Just set the stack entry to null */

                walk_state->num_operands--;
                walk_state->operands[walk_state->num_operands] = NULL;
        }

        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%u\n",
                          pop_count, walk_state, walk_state->num_operands));

        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_obj_stack_pop_and_delete
 *
 * PARAMETERS:  pop_count           - Number of objects/entries to pop
 *              walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Pop this walk's object stack and delete each object that is
 *              popped off.
 *
 ******************************************************************************/

void
acpi_ds_obj_stack_pop_and_delete(u32 pop_count,
                                 struct acpi_walk_state *walk_state)
{
        s32 i;
        union acpi_operand_object *obj_desc;

        ACPI_FUNCTION_NAME(ds_obj_stack_pop_and_delete);

        if (pop_count == 0) {
                return;
        }

        for (i = (s32)pop_count - 1; i >= 0; i--) {
                if (walk_state->num_operands == 0) {
                        return;
                }

                /* Pop the stack and delete an object if present in this stack entry */

                walk_state->num_operands--;
                obj_desc = walk_state->operands[i];
                if (obj_desc) {
                        acpi_ut_remove_reference(walk_state->operands[i]);
                        walk_state->operands[i] = NULL;
                }
        }

        ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%X\n",
                          pop_count, walk_state, walk_state->num_operands));
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_get_current_walk_state
 *
 * PARAMETERS:  thread          - Get current active state for this Thread
 *
 * RETURN:      Pointer to the current walk state
 *
 * DESCRIPTION: Get the walk state that is at the head of the list (the "current"
 *              walk state.)
 *
 ******************************************************************************/

struct acpi_walk_state *acpi_ds_get_current_walk_state(struct acpi_thread_state
                                                       *thread)
{
        ACPI_FUNCTION_NAME(ds_get_current_walk_state);

        if (!thread) {
                return (NULL);
        }

        ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "Current WalkState %p\n",
                          thread->walk_state_list));

        return (thread->walk_state_list);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_push_walk_state
 *
 * PARAMETERS:  walk_state      - State to push
 *              thread          - Thread state object
 *
 * RETURN:      None
 *
 * DESCRIPTION: Place the Thread state at the head of the state list
 *
 ******************************************************************************/

void
acpi_ds_push_walk_state(struct acpi_walk_state *walk_state,
                        struct acpi_thread_state *thread)
{
        ACPI_FUNCTION_TRACE(ds_push_walk_state);

        walk_state->next = thread->walk_state_list;
        thread->walk_state_list = walk_state;

        return_VOID;
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_pop_walk_state
 *
 * PARAMETERS:  thread      - Current thread state
 *
 * RETURN:      A walk_state object popped from the thread's stack
 *
 * DESCRIPTION: Remove and return the walkstate object that is at the head of
 *              the walk stack for the given walk list. NULL indicates that
 *              the list is empty.
 *
 ******************************************************************************/

struct acpi_walk_state *acpi_ds_pop_walk_state(struct acpi_thread_state *thread)
{
        struct acpi_walk_state *walk_state;

        ACPI_FUNCTION_TRACE(ds_pop_walk_state);

        walk_state = thread->walk_state_list;

        if (walk_state) {

                /* Next walk state becomes the current walk state */

                thread->walk_state_list = walk_state->next;

                /*
                 * Don't clear the NEXT field, this serves as an indicator
                 * that there is a parent WALK STATE
                 * Do Not: walk_state->Next = NULL;
                 */
        }

        return_PTR(walk_state);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_create_walk_state
 *
 * PARAMETERS:  owner_id        - ID for object creation
 *              origin          - Starting point for this walk
 *              method_desc     - Method object
 *              thread          - Current thread state
 *
 * RETURN:      Pointer to the new walk state.
 *
 * DESCRIPTION: Allocate and initialize a new walk state. The current walk
 *              state is set to this new state.
 *
 ******************************************************************************/

struct acpi_walk_state *acpi_ds_create_walk_state(acpi_owner_id owner_id,
                                                  union acpi_parse_object
                                                  *origin,
                                                  union acpi_operand_object
                                                  *method_desc,
                                                  struct acpi_thread_state
                                                  *thread)
{
        struct acpi_walk_state *walk_state;

        ACPI_FUNCTION_TRACE(ds_create_walk_state);

        walk_state = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_walk_state));
        if (!walk_state) {
                return_PTR(NULL);
        }

        walk_state->descriptor_type = ACPI_DESC_TYPE_WALK;
        walk_state->method_desc = method_desc;
        walk_state->owner_id = owner_id;
        walk_state->origin = origin;
        walk_state->thread = thread;

        walk_state->parser_state.start_op = origin;

        /* Init the method args/local */

#ifndef ACPI_CONSTANT_EVAL_ONLY
        acpi_ds_method_data_init(walk_state);
#endif

        /* Put the new state at the head of the walk list */

        if (thread) {
                acpi_ds_push_walk_state(walk_state, thread);
        }

        return_PTR(walk_state);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_init_aml_walk
 *
 * PARAMETERS:  walk_state      - New state to be initialized
 *              op              - Current parse op
 *              method_node     - Control method NS node, if any
 *              aml_start       - Start of AML
 *              aml_length      - Length of AML
 *              info            - Method info block (params, etc.)
 *              pass_number     - 1, 2, or 3
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Initialize a walk state for a pass 1 or 2 parse tree walk
 *
 ******************************************************************************/

acpi_status
acpi_ds_init_aml_walk(struct acpi_walk_state *walk_state,
                      union acpi_parse_object *op,
                      struct acpi_namespace_node *method_node,
                      u8 * aml_start,
                      u32 aml_length,
                      struct acpi_evaluate_info *info, u8 pass_number)
{
        acpi_status status;
        struct acpi_parse_state *parser_state = &walk_state->parser_state;
        union acpi_parse_object *extra_op;

        ACPI_FUNCTION_TRACE(ds_init_aml_walk);

        walk_state->parser_state.aml =
            walk_state->parser_state.aml_start =
            walk_state->parser_state.aml_end =
            walk_state->parser_state.pkg_end = aml_start;
        /* Avoid undefined behavior: applying zero offset to null pointer */
        if (aml_length != 0) {
                walk_state->parser_state.aml_end += aml_length;
                walk_state->parser_state.pkg_end += aml_length;
        }

        /* The next_op of the next_walk will be the beginning of the method */

        walk_state->next_op = NULL;
        walk_state->pass_number = pass_number;

        if (info) {
                walk_state->params = info->parameters;
                walk_state->caller_return_desc = &info->return_object;
        }

        status = acpi_ps_init_scope(&walk_state->parser_state, op);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        if (method_node) {
                walk_state->parser_state.start_node = method_node;
                walk_state->walk_type = ACPI_WALK_METHOD;
                walk_state->method_node = method_node;
                walk_state->method_desc =
                    acpi_ns_get_attached_object(method_node);

                /* Push start scope on scope stack and make it current  */

                status =
                    acpi_ds_scope_stack_push(method_node, ACPI_TYPE_METHOD,
                                             walk_state);
                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }

                /* Init the method arguments */

                status = acpi_ds_method_data_init_args(walk_state->params,
                                                       ACPI_METHOD_NUM_ARGS,
                                                       walk_state);
                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }
        } else {
                /*
                 * Setup the current scope.
                 * Find a Named Op that has a namespace node associated with it.
                 * search upwards from this Op. Current scope is the first
                 * Op with a namespace node.
                 */
                extra_op = parser_state->start_op;
                while (extra_op && !extra_op->common.node) {
                        extra_op = extra_op->common.parent;
                }

                if (!extra_op) {
                        parser_state->start_node = NULL;
                } else {
                        parser_state->start_node = extra_op->common.node;
                }

                if (parser_state->start_node) {

                        /* Push start scope on scope stack and make it current  */

                        status =
                            acpi_ds_scope_stack_push(parser_state->start_node,
                                                     parser_state->start_node->
                                                     type, walk_state);
                        if (ACPI_FAILURE(status)) {
                                return_ACPI_STATUS(status);
                        }
                }
        }

        status = acpi_ds_init_callbacks(walk_state, pass_number);
        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_delete_walk_state
 *
 * PARAMETERS:  walk_state      - State to delete
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Delete a walk state including all internal data structures
 *
 ******************************************************************************/

void acpi_ds_delete_walk_state(struct acpi_walk_state *walk_state)
{
        union acpi_generic_state *state;

        ACPI_FUNCTION_TRACE_PTR(ds_delete_walk_state, walk_state);

        if (!walk_state) {
                return_VOID;
        }

        if (walk_state->descriptor_type != ACPI_DESC_TYPE_WALK) {
                ACPI_ERROR((AE_INFO, "%p is not a valid walk state",
                            walk_state));
                return_VOID;
        }

        /* There should not be any open scopes */

        if (walk_state->parser_state.scope) {
                ACPI_ERROR((AE_INFO, "%p walk still has a scope list",
                            walk_state));
                acpi_ps_cleanup_scope(&walk_state->parser_state);
        }

        /* Always must free any linked control states */

        while (walk_state->control_state) {
                state = walk_state->control_state;
                walk_state->control_state = state->common.next;

                acpi_ut_delete_generic_state(state);
        }

        /* Always must free any linked parse states */

        while (walk_state->scope_info) {
                state = walk_state->scope_info;
                walk_state->scope_info = state->common.next;

                acpi_ut_delete_generic_state(state);
        }

        /* Always must free any stacked result states */

        while (walk_state->results) {
                state = walk_state->results;
                walk_state->results = state->common.next;

                acpi_ut_delete_generic_state(state);
        }

        ACPI_FREE(walk_state);
        return_VOID;
}