// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: tbutils - ACPI Table utilities
 *
 * Copyright (C) 2000 - 2025, Intel Corp.
 *
 *****************************************************************************/

#include <acpi/acpi.h>
#include "accommon.h"
#include "actables.h"

#define _COMPONENT          ACPI_TABLES
ACPI_MODULE_NAME("tbutils")

/* Local prototypes */
static acpi_physical_address
acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size);

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_initialize_facs
 *
 * PARAMETERS:  None
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create a permanent mapping for the FADT and save it in a global
 *              for accessing the Global Lock and Firmware Waking Vector
 *
 ******************************************************************************/

acpi_status acpi_tb_initialize_facs(void)
{
        struct acpi_table_facs *facs;

        if (acpi_gbl_FADT.Xfacs &&
                   (!acpi_gbl_FADT.facs
                    || !acpi_gbl_use32_bit_facs_addresses)) {
                (void)acpi_get_table_by_index(acpi_gbl_xfacs_index,
                                              ACPI_CAST_INDIRECT_PTR(struct
                                                                     acpi_table_header,
                                                                     &facs));
                acpi_gbl_FACS = facs;
        } else if (acpi_gbl_FADT.facs) {
                (void)acpi_get_table_by_index(acpi_gbl_facs_index,
                                              ACPI_CAST_INDIRECT_PTR(struct
                                                                     acpi_table_header,
                                                                     &facs));
                acpi_gbl_FACS = facs;
        }

        /* If there is no FACS, just continue. There was already an error msg */

        return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_check_dsdt_header
 *
 * PARAMETERS:  None
 *
 * RETURN:      None
 *
 * DESCRIPTION: Quick compare to check validity of the DSDT. This will detect
 *              if the DSDT has been replaced from outside the OS and/or if
 *              the DSDT header has been corrupted.
 *
 ******************************************************************************/

void acpi_tb_check_dsdt_header(void)
{

        /* Compare original length and checksum to current values */

        if (acpi_gbl_original_dsdt_header.length != acpi_gbl_DSDT->length ||
            acpi_gbl_original_dsdt_header.checksum != acpi_gbl_DSDT->checksum) {
                ACPI_BIOS_ERROR((AE_INFO,
                                 "The DSDT has been corrupted or replaced - "
                                 "old, new headers below"));

                acpi_tb_print_table_header(0, &acpi_gbl_original_dsdt_header);
                acpi_tb_print_table_header(0, acpi_gbl_DSDT);

                ACPI_ERROR((AE_INFO,
                            "Please send DMI info to linux-acpi@vger.kernel.org\n"
                            "If system does not work as expected, please boot with acpi=copy_dsdt"));

                /* Disable further error messages */

                acpi_gbl_original_dsdt_header.length = acpi_gbl_DSDT->length;
                acpi_gbl_original_dsdt_header.checksum =
                    acpi_gbl_DSDT->checksum;
        }
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_copy_dsdt
 *
 * PARAMETERS:  table_index         - Index of installed table to copy
 *
 * RETURN:      The copied DSDT
 *
 * DESCRIPTION: Implements a subsystem option to copy the DSDT to local memory.
 *              Some very bad BIOSs are known to either corrupt the DSDT or
 *              install a new, bad DSDT. This copy works around the problem.
 *
 ******************************************************************************/

struct acpi_table_header *acpi_tb_copy_dsdt(u32 table_index)
{
        struct acpi_table_header *new_table;
        struct acpi_table_desc *table_desc;

        table_desc = &acpi_gbl_root_table_list.tables[table_index];

        new_table = ACPI_ALLOCATE(table_desc->length);
        if (!new_table) {
                ACPI_ERROR((AE_INFO, "Could not copy DSDT of length 0x%X",
                            table_desc->length));
                return (NULL);
        }

        memcpy(new_table, table_desc->pointer, table_desc->length);
        acpi_tb_uninstall_table(table_desc);

        acpi_tb_init_table_descriptor(&acpi_gbl_root_table_list.
                                      tables[acpi_gbl_dsdt_index],
                                      ACPI_PTR_TO_PHYSADDR(new_table),
                                      ACPI_TABLE_ORIGIN_INTERNAL_VIRTUAL,
                                      new_table);

        ACPI_INFO(("Forced DSDT copy: length 0x%05X copied locally, original unmapped", new_table->length));

        return (new_table);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_get_root_table_entry
 *
 * PARAMETERS:  table_entry         - Pointer to the RSDT/XSDT table entry
 *              table_entry_size    - sizeof 32 or 64 (RSDT or XSDT)
 *
 * RETURN:      Physical address extracted from the root table
 *
 * DESCRIPTION: Get one root table entry. Handles 32-bit and 64-bit cases on
 *              both 32-bit and 64-bit platforms
 *
 * NOTE:        acpi_physical_address is 32-bit on 32-bit platforms, 64-bit on
 *              64-bit platforms.
 *
 ******************************************************************************/

static acpi_physical_address
acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size)
{
        u32 address32;
        u64 address64;

        /*
         * Get the table physical address (32-bit for RSDT, 64-bit for XSDT):
         * Note: Addresses are 32-bit aligned (not 64) in both RSDT and XSDT
         */
        if (table_entry_size == ACPI_RSDT_ENTRY_SIZE) {
                /*
                 * 32-bit platform, RSDT: Return 32-bit table entry
                 * 64-bit platform, RSDT: Expand 32-bit to 64-bit and return
                 */
                ACPI_MOVE_32_TO_32(&address32, table_entry);
                return address32;
        } else {
                /*
                 * 32-bit platform, XSDT: Truncate 64-bit to 32-bit and return
                 * 64-bit platform, XSDT: Move (unaligned) 64-bit to local,
                 *  return 64-bit
                 */
                ACPI_MOVE_64_TO_64(&address64, table_entry);

#if ACPI_MACHINE_WIDTH == 32
                if (address64 > ACPI_UINT32_MAX) {

                        /* Will truncate 64-bit address to 32 bits, issue warning */

                        ACPI_BIOS_WARNING((AE_INFO,
                                           "64-bit Physical Address in XSDT is too large (0x%8.8X%8.8X),"
                                           " truncating",
                                           ACPI_FORMAT_UINT64(address64)));
                }
#endif
                return ((acpi_physical_address)(address64));
        }
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_parse_root_table
 *
 * PARAMETERS:  rsdp_address        - Pointer to the RSDP
 *
 * RETURN:      Status
 *
 * DESCRIPTION: This function is called to parse the Root System Description
 *              Table (RSDT or XSDT)
 *
 * NOTE:        Tables are mapped (not copied) for efficiency. The FACS must
 *              be mapped and cannot be copied because it contains the actual
 *              memory location of the ACPI Global Lock.
 *
 ******************************************************************************/

acpi_status ACPI_INIT_FUNCTION
acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
{
        struct acpi_table_rsdp *rsdp;
        u32 table_entry_size;
        u32 i;
        u32 table_count;
        struct acpi_table_header *table;
        acpi_physical_address address;
        u32 length;
        u8 *table_entry;
        acpi_status status;
        u32 table_index;

        ACPI_FUNCTION_TRACE(tb_parse_root_table);

        /* Map the entire RSDP and extract the address of the RSDT or XSDT */

        rsdp = acpi_os_map_memory(rsdp_address, sizeof(struct acpi_table_rsdp));
        if (!rsdp) {
                return_ACPI_STATUS(AE_NO_MEMORY);
        }

        acpi_tb_print_table_header(rsdp_address,
                                   ACPI_CAST_PTR(struct acpi_table_header,
                                                 rsdp));

        /* Use XSDT if present and not overridden. Otherwise, use RSDT */

        if ((rsdp->revision > 1) &&
            rsdp->xsdt_physical_address && !acpi_gbl_do_not_use_xsdt) {
                /*
                 * RSDP contains an XSDT (64-bit physical addresses). We must use
                 * the XSDT if the revision is > 1 and the XSDT pointer is present,
                 * as per the ACPI specification.
                 */
                address = (acpi_physical_address)rsdp->xsdt_physical_address;
                table_entry_size = ACPI_XSDT_ENTRY_SIZE;
        } else {
                /* Root table is an RSDT (32-bit physical addresses) */

                address = (acpi_physical_address)rsdp->rsdt_physical_address;
                table_entry_size = ACPI_RSDT_ENTRY_SIZE;
        }

        /*
         * It is not possible to map more than one entry in some environments,
         * so unmap the RSDP here before mapping other tables
         */
        acpi_os_unmap_memory(rsdp, sizeof(struct acpi_table_rsdp));

        /* Map the RSDT/XSDT table header to get the full table length */

        table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
        if (!table) {
                return_ACPI_STATUS(AE_NO_MEMORY);
        }

        acpi_tb_print_table_header(address, table);

        /*
         * Validate length of the table, and map entire table.
         * Minimum length table must contain at least one entry.
         */
        length = table->length;
        acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));

        if (length < (sizeof(struct acpi_table_header) + table_entry_size)) {
                ACPI_BIOS_ERROR((AE_INFO,
                                 "Invalid table length 0x%X in RSDT/XSDT",
                                 length));
                return_ACPI_STATUS(AE_INVALID_TABLE_LENGTH);
        }

        table = acpi_os_map_memory(address, length);
        if (!table) {
                return_ACPI_STATUS(AE_NO_MEMORY);
        }

        /* Validate the root table checksum */

        status = acpi_ut_verify_checksum(table, length);
        if (ACPI_FAILURE(status)) {
                acpi_os_unmap_memory(table, length);
                return_ACPI_STATUS(status);
        }

        /* Get the number of entries and pointer to first entry */

        table_count = (u32)((table->length - sizeof(struct acpi_table_header)) /
                            table_entry_size);
        table_entry = ACPI_ADD_PTR(u8, table, sizeof(struct acpi_table_header));

        /* Initialize the root table array from the RSDT/XSDT */

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

                /* Get the table physical address (32-bit for RSDT, 64-bit for XSDT) */

                address =
                    acpi_tb_get_root_table_entry(table_entry, table_entry_size);

                /* Skip NULL entries in RSDT/XSDT */

                if (!address) {
                        goto next_table;
                }

                status = acpi_tb_install_standard_table(address,
                                                        ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
                                                        NULL, FALSE, TRUE,
                                                        &table_index);

                if (ACPI_SUCCESS(status) &&
                    ACPI_COMPARE_NAMESEG(&acpi_gbl_root_table_list.
                                         tables[table_index].signature,
                                         ACPI_SIG_FADT)) {
                        acpi_gbl_fadt_index = table_index;
                        acpi_tb_parse_fadt();
                }

next_table:

                table_entry += table_entry_size;
        }

        acpi_os_unmap_memory(table, length);
        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_get_table
 *
 * PARAMETERS:  table_desc          - Table descriptor
 *              out_table           - Where the pointer to the table is returned
 *
 * RETURN:      Status and pointer to the requested table
 *
 * DESCRIPTION: Increase a reference to a table descriptor and return the
 *              validated table pointer.
 *              If the table descriptor is an entry of the root table list,
 *              this API must be invoked with ACPI_MTX_TABLES acquired.
 *
 ******************************************************************************/

acpi_status
acpi_tb_get_table(struct acpi_table_desc *table_desc,
                  struct acpi_table_header **out_table)
{
        acpi_status status;

        ACPI_FUNCTION_TRACE(acpi_tb_get_table);

        if (table_desc->validation_count == 0) {

                /* Table need to be "VALIDATED" */

                status = acpi_tb_validate_table(table_desc);
                if (ACPI_FAILURE(status)) {
                        return_ACPI_STATUS(status);
                }
        }

        if (table_desc->validation_count < ACPI_MAX_TABLE_VALIDATIONS) {
                table_desc->validation_count++;

                /*
                 * Detect validation_count overflows to ensure that the warning
                 * message will only be printed once.
                 */
                if (table_desc->validation_count >= ACPI_MAX_TABLE_VALIDATIONS) {
                        ACPI_WARNING((AE_INFO,
                                      "Table %p, Validation count overflows\n",
                                      table_desc));
                }
        }

        *out_table = table_desc->pointer;
        return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_put_table
 *
 * PARAMETERS:  table_desc          - Table descriptor
 *
 * RETURN:      None
 *
 * DESCRIPTION: Decrease a reference to a table descriptor and release the
 *              validated table pointer if no references.
 *              If the table descriptor is an entry of the root table list,
 *              this API must be invoked with ACPI_MTX_TABLES acquired.
 *
 ******************************************************************************/

void acpi_tb_put_table(struct acpi_table_desc *table_desc)
{

        ACPI_FUNCTION_TRACE(acpi_tb_put_table);

        if (table_desc->validation_count < ACPI_MAX_TABLE_VALIDATIONS) {
                table_desc->validation_count--;

                /*
                 * Detect validation_count underflows to ensure that the warning
                 * message will only be printed once.
                 */
                if (table_desc->validation_count >= ACPI_MAX_TABLE_VALIDATIONS) {
                        ACPI_WARNING((AE_INFO,
                                      "Table %p, Validation count underflows\n",
                                      table_desc));
                        return_VOID;
                }
        }

        if (table_desc->validation_count == 0) {

                /* Table need to be "INVALIDATED" */

                acpi_tb_invalidate_table(table_desc);
        }

        return_VOID;
}