| /****************************************************************************** |
| * |
| * Module Name: tbxfroot - Find the root ACPI table (RSDT) |
| * |
| *****************************************************************************/ |
| |
| /* |
| * Copyright (C) 2000 - 2020, Intel Corp. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions, and the following disclaimer, |
| * without modification. |
| * 2. Redistributions in binary form must reproduce at minimum a disclaimer |
| * substantially similar to the "NO WARRANTY" disclaimer below |
| * ("Disclaimer") and any redistribution must be conditioned upon |
| * including a substantially similar Disclaimer requirement for further |
| * binary redistribution. |
| * 3. Neither the names of the above-listed copyright holders nor the names |
| * of any contributors may be used to endorse or promote products derived |
| * from this software without specific prior written permission. |
| * |
| * NO WARRANTY |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING |
| * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGES. |
| */ |
| |
| #include "acpi.h" |
| #include "accommon.h" |
| #include "actables.h" |
| |
| |
| #define _COMPONENT ACPI_TABLES |
| ACPI_MODULE_NAME ("tbxfroot") |
| |
| |
| /******************************************************************************* |
| * |
| * FUNCTION: AcpiTbGetRsdpLength |
| * |
| * PARAMETERS: Rsdp - Pointer to RSDP |
| * |
| * RETURN: Table length |
| * |
| * DESCRIPTION: Get the length of the RSDP |
| * |
| ******************************************************************************/ |
| |
| UINT32 |
| AcpiTbGetRsdpLength ( |
| ACPI_TABLE_RSDP *Rsdp) |
| { |
| |
| if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature)) |
| { |
| /* BAD Signature */ |
| |
| return (0); |
| } |
| |
| /* "Length" field is available if table version >= 2 */ |
| |
| if (Rsdp->Revision >= 2) |
| { |
| return (Rsdp->Length); |
| } |
| else |
| { |
| return (ACPI_RSDP_CHECKSUM_LENGTH); |
| } |
| } |
| |
| |
| /******************************************************************************* |
| * |
| * FUNCTION: AcpiTbValidateRsdp |
| * |
| * PARAMETERS: Rsdp - Pointer to unvalidated RSDP |
| * |
| * RETURN: Status |
| * |
| * DESCRIPTION: Validate the RSDP (ptr) |
| * |
| ******************************************************************************/ |
| |
| ACPI_STATUS |
| AcpiTbValidateRsdp ( |
| ACPI_TABLE_RSDP *Rsdp) |
| { |
| |
| /* |
| * The signature and checksum must both be correct |
| * |
| * Note: Sometimes there exists more than one RSDP in memory; the valid |
| * RSDP has a valid checksum, all others have an invalid checksum. |
| */ |
| if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature)) |
| { |
| /* Nope, BAD Signature */ |
| |
| return (AE_BAD_SIGNATURE); |
| } |
| |
| /* Check the standard checksum */ |
| |
| if (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0) |
| { |
| return (AE_BAD_CHECKSUM); |
| } |
| |
| /* Check extended checksum if table version >= 2 */ |
| |
| if ((Rsdp->Revision >= 2) && |
| (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0)) |
| { |
| return (AE_BAD_CHECKSUM); |
| } |
| |
| return (AE_OK); |
| } |
| |
| |
| /******************************************************************************* |
| * |
| * FUNCTION: AcpiFindRootPointer |
| * |
| * PARAMETERS: TableAddress - Where the table pointer is returned |
| * |
| * RETURN: Status, RSDP physical address |
| * |
| * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor |
| * pointer structure. If it is found, set *RSDP to point to it. |
| * |
| * NOTE1: The RSDP must be either in the first 1K of the Extended |
| * BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.) |
| * Only a 32-bit physical address is necessary. |
| * |
| * NOTE2: This function is always available, regardless of the |
| * initialization state of the rest of ACPI. |
| * |
| ******************************************************************************/ |
| |
| ACPI_STATUS ACPI_INIT_FUNCTION |
| AcpiFindRootPointer ( |
| ACPI_PHYSICAL_ADDRESS *TableAddress) |
| { |
| UINT8 *TablePtr; |
| UINT8 *MemRover; |
| UINT32 PhysicalAddress; |
| |
| |
| ACPI_FUNCTION_TRACE (AcpiFindRootPointer); |
| |
| |
| /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */ |
| |
| TablePtr = AcpiOsMapMemory ( |
| (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION, |
| ACPI_EBDA_PTR_LENGTH); |
| if (!TablePtr) |
| { |
| ACPI_ERROR ((AE_INFO, |
| "Could not map memory at 0x%8.8X for length %u", |
| ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH)); |
| |
| return_ACPI_STATUS (AE_NO_MEMORY); |
| } |
| |
| ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr); |
| |
| /* Convert segment part to physical address */ |
| |
| PhysicalAddress <<= 4; |
| AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH); |
| |
| /* EBDA present? */ |
| |
| if (PhysicalAddress > 0x400) |
| { |
| /* |
| * 1b) Search EBDA paragraphs (EBDA is required to be a |
| * minimum of 1K length) |
| */ |
| TablePtr = AcpiOsMapMemory ( |
| (ACPI_PHYSICAL_ADDRESS) PhysicalAddress, |
| ACPI_EBDA_WINDOW_SIZE); |
| if (!TablePtr) |
| { |
| ACPI_ERROR ((AE_INFO, |
| "Could not map memory at 0x%8.8X for length %u", |
| PhysicalAddress, ACPI_EBDA_WINDOW_SIZE)); |
| |
| return_ACPI_STATUS (AE_NO_MEMORY); |
| } |
| |
| MemRover = AcpiTbScanMemoryForRsdp ( |
| TablePtr, ACPI_EBDA_WINDOW_SIZE); |
| AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE); |
| |
| if (MemRover) |
| { |
| /* Return the physical address */ |
| |
| PhysicalAddress += |
| (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr); |
| |
| *TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress; |
| return_ACPI_STATUS (AE_OK); |
| } |
| } |
| |
| /* |
| * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh |
| */ |
| TablePtr = AcpiOsMapMemory ( |
| (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE, |
| ACPI_HI_RSDP_WINDOW_SIZE); |
| |
| if (!TablePtr) |
| { |
| ACPI_ERROR ((AE_INFO, |
| "Could not map memory at 0x%8.8X for length %u", |
| ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE)); |
| |
| return_ACPI_STATUS (AE_NO_MEMORY); |
| } |
| |
| MemRover = AcpiTbScanMemoryForRsdp ( |
| TablePtr, ACPI_HI_RSDP_WINDOW_SIZE); |
| AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE); |
| |
| if (MemRover) |
| { |
| /* Return the physical address */ |
| |
| PhysicalAddress = (UINT32) |
| (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr)); |
| |
| *TableAddress = (ACPI_PHYSICAL_ADDRESS) PhysicalAddress; |
| return_ACPI_STATUS (AE_OK); |
| } |
| |
| /* A valid RSDP was not found */ |
| |
| ACPI_BIOS_ERROR ((AE_INFO, "A valid RSDP was not found")); |
| return_ACPI_STATUS (AE_NOT_FOUND); |
| } |
| |
| ACPI_EXPORT_SYMBOL_INIT (AcpiFindRootPointer) |
| |
| |
| /******************************************************************************* |
| * |
| * FUNCTION: AcpiTbScanMemoryForRsdp |
| * |
| * PARAMETERS: StartAddress - Starting pointer for search |
| * Length - Maximum length to search |
| * |
| * RETURN: Pointer to the RSDP if found, otherwise NULL. |
| * |
| * DESCRIPTION: Search a block of memory for the RSDP signature |
| * |
| ******************************************************************************/ |
| |
| UINT8 * |
| AcpiTbScanMemoryForRsdp ( |
| UINT8 *StartAddress, |
| UINT32 Length) |
| { |
| ACPI_STATUS Status; |
| UINT8 *MemRover; |
| UINT8 *EndAddress; |
| |
| |
| ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp); |
| |
| |
| EndAddress = StartAddress + Length; |
| |
| /* Search from given start address for the requested length */ |
| |
| for (MemRover = StartAddress; MemRover < EndAddress; |
| MemRover += ACPI_RSDP_SCAN_STEP) |
| { |
| /* The RSDP signature and checksum must both be correct */ |
| |
| Status = AcpiTbValidateRsdp ( |
| ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover)); |
| if (ACPI_SUCCESS (Status)) |
| { |
| /* Sig and checksum valid, we have found a real RSDP */ |
| |
| ACPI_DEBUG_PRINT ((ACPI_DB_INFO, |
| "RSDP located at physical address %p\n", MemRover)); |
| return_PTR (MemRover); |
| } |
| |
| /* No sig match or bad checksum, keep searching */ |
| } |
| |
| /* Searched entire block, no RSDP was found */ |
| |
| ACPI_DEBUG_PRINT ((ACPI_DB_INFO, |
| "Searched entire block from %p, valid RSDP was not found\n", |
| StartAddress)); |
| return_PTR (NULL); |
| } |
