// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: exconfig - Namespace reconfiguration (Load/Unload opcodes)
 *
 * Copyright (C) 2000 - 2020, Intel Corp.
 *
 *****************************************************************************/

#include <acpi/acpi.h>
#include "accommon.h"
#include "acinterp.h"
#include "acnamesp.h"
#include "actables.h"
#include "acdispat.h"
#include "acevents.h"
#include "amlcode.h"

#define _COMPONENT          ACPI_EXECUTER
ACPI_MODULE_NAME("exconfig")

/* Local prototypes */
static acpi_status
acpi_ex_add_table(u32 table_index, union acpi_operand_object **ddb_handle);

static acpi_status
acpi_ex_region_read(union acpi_operand_object *obj_desc,
                    u32 length, u8 *buffer);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_add_table
 *
 * PARAMETERS:  table               - Pointer to raw table
 *              parent_node         - Where to load the table (scope)
 *              ddb_handle          - Where to return the table handle.
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Common function to Install and Load an ACPI table with a
 *              returned table handle.
 *
 ******************************************************************************/

static acpi_status
acpi_ex_add_table(u32 table_index, union acpi_operand_object **ddb_handle)
{
        union acpi_operand_object *obj_desc;

        ACPI_FUNCTION_TRACE(ex_add_table);

        /* Create an object to be the table handle */

        obj_desc = acpi_ut_create_internal_object(ACPI_TYPE_LOCAL_REFERENCE);
        if (!obj_desc) {
                return_ACPI_STATUS(AE_NO_MEMORY);
        }

        /* Init the table handle */

        obj_desc->common.flags |= AOPOBJ_DATA_VALID;
        obj_desc->reference.class = ACPI_REFCLASS_TABLE;
        obj_desc->reference.value = table_index;
        *ddb_handle = obj_desc;
        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_load_table_op
 *
 * PARAMETERS:  walk_state          - Current state with operands
 *              return_desc         - Where to store the return object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Load an ACPI table from the RSDT/XSDT
 *
 ******************************************************************************/

acpi_status
acpi_ex_load_table_op(struct acpi_walk_state *walk_state,
                      union acpi_operand_object **return_desc)
{
        acpi_status status;
        union acpi_operand_object **operand = &walk_state->operands[0];
        struct acpi_namespace_node *parent_node;
        struct acpi_namespace_node *start_node;
        struct acpi_namespace_node *parameter_node = NULL;
        union acpi_operand_object *ddb_handle;
        u32 table_index;

        ACPI_FUNCTION_TRACE(ex_load_table_op);

        /* Find the ACPI table in the RSDT/XSDT */

        acpi_ex_exit_interpreter();
        status = acpi_tb_find_table(operand[0]->string.pointer,
                                    operand[1]->string.pointer,
                                    operand[2]->string.pointer, &table_index);
        acpi_ex_enter_interpreter();
        if (ACPI_FAILURE(status)) {
                if (status != AE_NOT_FOUND) {
                        return_ACPI_STATUS(status);
                }

                /* Table not found, return an Integer=0 and AE_OK */

                ddb_handle = acpi_ut_create_integer_object((u64) 0);
                if (!ddb_handle) {
                        return_ACPI_STATUS(AE_NO_MEMORY);
                }

                *return_desc = ddb_handle;
                return_ACPI_STATUS(AE_OK);
        }

        /* Default nodes */

        start_node = walk_state->scope_info->scope.node;
        parent_node = acpi_gbl_root_node;

        /* root_path (optional parameter) */

        if (operand[3]->string.length > 0) {
                /*
                 * Find the node referenced by the root_path_string. This is the
                 * location within the namespace where the table will be loaded.
                 */
                status = acpi_ns_get_node_unlocked(start_node,
                                                   operand[3]->string.pointer,
                                                   ACPI_NS_SEARCH_PARENT,
                                                   &parent_node);
                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }
        }

        /* parameter_path (optional parameter) */

        if (operand[4]->string.length > 0) {
                if ((operand[4]->string.pointer[0] != AML_ROOT_PREFIX) &&
                    (operand[4]->string.pointer[0] != AML_PARENT_PREFIX)) {
                        /*
                         * Path is not absolute, so it will be relative to the node
                         * referenced by the root_path_string (or the NS root if omitted)
                         */
                        start_node = parent_node;
                }

                /* Find the node referenced by the parameter_path_string */

                status = acpi_ns_get_node_unlocked(start_node,
                                                   operand[4]->string.pointer,
                                                   ACPI_NS_SEARCH_PARENT,
                                                   &parameter_node);
                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }
        }

        /* Load the table into the namespace */

        ACPI_INFO(("Dynamic OEM Table Load:"));
        acpi_ex_exit_interpreter();
        status = acpi_tb_load_table(table_index, parent_node);
        acpi_ex_enter_interpreter();
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        status = acpi_ex_add_table(table_index, &ddb_handle);
        if (ACPI_FAILURE(status)) {
                return_ACPI_STATUS(status);
        }

        /* Complete the initialization/resolution of new objects */

        acpi_ex_exit_interpreter();
        acpi_ns_initialize_objects();
        acpi_ex_enter_interpreter();

        /* Parameter Data (optional) */

        if (parameter_node) {

                /* Store the parameter data into the optional parameter object */

                status = acpi_ex_store(operand[5],
                                       ACPI_CAST_PTR(union acpi_operand_object,
                                                     parameter_node),
                                       walk_state);
                if (ACPI_FAILURE(status)) {
                        (void)acpi_ex_unload_table(ddb_handle);

                        acpi_ut_remove_reference(ddb_handle);
                        return_ACPI_STATUS(status);
                }
        }

        *return_desc = ddb_handle;
        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_region_read
 *
 * PARAMETERS:  obj_desc        - Region descriptor
 *              length          - Number of bytes to read
 *              buffer          - Pointer to where to put the data
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Read data from an operation region. The read starts from the
 *              beginning of the region.
 *
 ******************************************************************************/

static acpi_status
acpi_ex_region_read(union acpi_operand_object *obj_desc, u32 length, u8 *buffer)
{
        acpi_status status;
        u64 value;
        u32 region_offset = 0;
        u32 i;

        /* Bytewise reads */

        for (i = 0; i < length; i++) {
                status =
                    acpi_ev_address_space_dispatch(obj_desc, NULL, ACPI_READ,
                                                   region_offset, 8, &value);
                if (ACPI_FAILURE(status)) {
                        return (status);
                }

                *buffer = (u8)value;
                buffer++;
                region_offset++;
        }

        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_load_op
 *
 * PARAMETERS:  obj_desc        - Region or Buffer/Field where the table will be
 *                                obtained
 *              target          - Where a handle to the table will be stored
 *              walk_state      - Current state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Load an ACPI table from a field or operation region
 *
 * NOTE: Region Fields (Field, bank_field, index_fields) are resolved to buffer
 *       objects before this code is reached.
 *
 *       If source is an operation region, it must refer to system_memory, as
 *       per the ACPI specification.
 *
 ******************************************************************************/

acpi_status
acpi_ex_load_op(union acpi_operand_object *obj_desc,
                union acpi_operand_object *target,
                struct acpi_walk_state *walk_state)
{
        union acpi_operand_object *ddb_handle;
        struct acpi_table_header *table_header;
        struct acpi_table_header *table;
        u32 table_index;
        acpi_status status;
        u32 length;

        ACPI_FUNCTION_TRACE(ex_load_op);

        /* Source Object can be either an op_region or a Buffer/Field */

        switch (obj_desc->common.type) {
        case ACPI_TYPE_REGION:

                ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
                                  "Load table from Region %p\n", obj_desc));

                /* Region must be system_memory (from ACPI spec) */

                if (obj_desc->region.space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
                        return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
                }

                /*
                 * If the Region Address and Length have not been previously
                 * evaluated, evaluate them now and save the results.
                 */
                if (!(obj_desc->common.flags & AOPOBJ_DATA_VALID)) {
                        status = acpi_ds_get_region_arguments(obj_desc);
                        if (ACPI_FAILURE(status)) {
                                return_ACPI_STATUS(status);
                        }
                }

                /* Get the table header first so we can get the table length */

                table_header = ACPI_ALLOCATE(sizeof(struct acpi_table_header));
                if (!table_header) {
                        return_ACPI_STATUS(AE_NO_MEMORY);
                }

                status =
                    acpi_ex_region_read(obj_desc,
                                        sizeof(struct acpi_table_header),
                                        ACPI_CAST_PTR(u8, table_header));
                length = table_header->length;
                ACPI_FREE(table_header);

                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }

                /* Must have at least an ACPI table header */

                if (length < sizeof(struct acpi_table_header)) {
                        return_ACPI_STATUS(AE_INVALID_TABLE_LENGTH);
                }

                /*
                 * The original implementation simply mapped the table, with no copy.
                 * However, the memory region is not guaranteed to remain stable and
                 * we must copy the table to a local buffer. For example, the memory
                 * region is corrupted after suspend on some machines. Dynamically
                 * loaded tables are usually small, so this overhead is minimal.
                 *
                 * The latest implementation (5/2009) does not use a mapping at all.
                 * We use the low-level operation region interface to read the table
                 * instead of the obvious optimization of using a direct mapping.
                 * This maintains a consistent use of operation regions across the
                 * entire subsystem. This is important if additional processing must
                 * be performed in the (possibly user-installed) operation region
                 * handler. For example, acpi_exec and ASLTS depend on this.
                 */

                /* Allocate a buffer for the table */

                table = ACPI_ALLOCATE(length);
                if (!table) {
                        return_ACPI_STATUS(AE_NO_MEMORY);
                }

                /* Read the entire table */

                status = acpi_ex_region_read(obj_desc, length,
                                             ACPI_CAST_PTR(u8, table));
                if (ACPI_FAILURE(status)) {
                        ACPI_FREE(table);
                        return_ACPI_STATUS(status);
                }
                break;

        case ACPI_TYPE_BUFFER:  /* Buffer or resolved region_field */

                ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
                                  "Load table from Buffer or Field %p\n",
                                  obj_desc));

                /* Must have at least an ACPI table header */

                if (obj_desc->buffer.length < sizeof(struct acpi_table_header)) {
                        return_ACPI_STATUS(AE_INVALID_TABLE_LENGTH);
                }

                /* Get the actual table length from the table header */

                table_header =
                    ACPI_CAST_PTR(struct acpi_table_header,
                                  obj_desc->buffer.pointer);
                length = table_header->length;

                /* Table cannot extend beyond the buffer */

                if (length > obj_desc->buffer.length) {
                        return_ACPI_STATUS(AE_AML_BUFFER_LIMIT);
                }
                if (length < sizeof(struct acpi_table_header)) {
                        return_ACPI_STATUS(AE_INVALID_TABLE_LENGTH);
                }

                /*
                 * Copy the table from the buffer because the buffer could be
                 * modified or even deleted in the future
                 */
                table = ACPI_ALLOCATE(length);
                if (!table) {
                        return_ACPI_STATUS(AE_NO_MEMORY);
                }

                memcpy(table, table_header, length);
                break;

        default:

                return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
        }

        /* Install the new table into the local data structures */

        ACPI_INFO(("Dynamic OEM Table Load:"));
        acpi_ex_exit_interpreter();
        status = acpi_tb_install_and_load_table(ACPI_PTR_TO_PHYSADDR(table),
                                                ACPI_TABLE_ORIGIN_INTERNAL_VIRTUAL,
                                                TRUE, &table_index);
        acpi_ex_enter_interpreter();
        if (ACPI_FAILURE(status)) {

                /* Delete allocated table buffer */

                ACPI_FREE(table);
                return_ACPI_STATUS(status);
        }

        /*
         * Add the table to the namespace.
         *
         * Note: Load the table objects relative to the root of the namespace.
         * This appears to go against the ACPI specification, but we do it for
         * compatibility with other ACPI implementations.
         */
        status = acpi_ex_add_table(table_index, &ddb_handle);
        if (ACPI_FAILURE(status)) {

                /* On error, table_ptr was deallocated above */

                return_ACPI_STATUS(status);
        }

        /* Complete the initialization/resolution of new objects */

        acpi_ex_exit_interpreter();
        acpi_ns_initialize_objects();
        acpi_ex_enter_interpreter();

        /* Store the ddb_handle into the Target operand */

        status = acpi_ex_store(ddb_handle, target, walk_state);
        if (ACPI_FAILURE(status)) {
                (void)acpi_ex_unload_table(ddb_handle);

                /* table_ptr was deallocated above */

                acpi_ut_remove_reference(ddb_handle);
                return_ACPI_STATUS(status);
        }

        /* Remove the reference by added by acpi_ex_store above */

        acpi_ut_remove_reference(ddb_handle);
        return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_unload_table
 *
 * PARAMETERS:  ddb_handle          - Handle to a previously loaded table
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Unload an ACPI table
 *
 ******************************************************************************/

acpi_status acpi_ex_unload_table(union acpi_operand_object *ddb_handle)
{
        acpi_status status = AE_OK;
        union acpi_operand_object *table_desc = ddb_handle;
        u32 table_index;

        ACPI_FUNCTION_TRACE(ex_unload_table);

        /*
         * Temporarily emit a warning so that the ASL for the machine can be
         * hopefully obtained. This is to say that the Unload() operator is
         * extremely rare if not completely unused.
         */
        ACPI_WARNING((AE_INFO, "Received request to unload an ACPI table"));

        /*
         * May 2018: Unload is no longer supported for the following reasons:
         * 1) A correct implementation on some hosts may not be possible.
         * 2) Other ACPI implementations do not correctly/fully support it.
         * 3) It requires host device driver support which does not exist.
         *    (To properly support namespace unload out from underneath.)
         * 4) This AML operator has never been seen in the field.
         */
        ACPI_EXCEPTION((AE_INFO, AE_NOT_IMPLEMENTED,
                        "AML Unload operator is not supported"));

        /*
         * Validate the handle
         * Although the handle is partially validated in acpi_ex_reconfiguration()
         * when it calls acpi_ex_resolve_operands(), the handle is more completely
         * validated here.
         *
         * Handle must be a valid operand object of type reference. Also, the
         * ddb_handle must still be marked valid (table has not been previously
         * unloaded)
         */
        if ((!ddb_handle) ||
            (ACPI_GET_DESCRIPTOR_TYPE(ddb_handle) != ACPI_DESC_TYPE_OPERAND) ||
            (ddb_handle->common.type != ACPI_TYPE_LOCAL_REFERENCE) ||
            (!(ddb_handle->common.flags & AOPOBJ_DATA_VALID))) {
                return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
        }

        /* Get the table index from the ddb_handle */

        table_index = table_desc->reference.value;

        /*
         * Release the interpreter lock so that the table lock won't have
         * strict order requirement against it.
         */
        acpi_ex_exit_interpreter();
        status = acpi_tb_unload_table(table_index);
        acpi_ex_enter_interpreter();

        /*
         * Invalidate the handle. We do this because the handle may be stored
         * in a named object and may not be actually deleted until much later.
         */
        if (ACPI_SUCCESS(status)) {
                ddb_handle->common.flags &= ~AOPOBJ_DATA_VALID;
        }
        return_ACPI_STATUS(status);
}