v4.19.13 snapshot.
diff --git a/drivers/acpi/acpica/tbxfroot.c b/drivers/acpi/acpica/tbxfroot.c
new file mode 100644
index 0000000..483d0ce
--- /dev/null
+++ b/drivers/acpi/acpica/tbxfroot.c
@@ -0,0 +1,267 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/******************************************************************************
+ *
+ * Module Name: tbxfroot - Find the root ACPI table (RSDT)
+ *
+ * Copyright (C) 2000 - 2018, Intel Corp.
+ *
+ *****************************************************************************/
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+#include "actables.h"
+
+#define _COMPONENT ACPI_TABLES
+ACPI_MODULE_NAME("tbxfroot")
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_tb_get_rsdp_length
+ *
+ * PARAMETERS: rsdp - Pointer to RSDP
+ *
+ * RETURN: Table length
+ *
+ * DESCRIPTION: Get the length of the RSDP
+ *
+ ******************************************************************************/
+u32 acpi_tb_get_rsdp_length(struct 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: acpi_tb_validate_rsdp
+ *
+ * PARAMETERS: rsdp - Pointer to unvalidated RSDP
+ *
+ * RETURN: Status
+ *
+ * DESCRIPTION: Validate the RSDP (ptr)
+ *
+ ******************************************************************************/
+
+acpi_status acpi_tb_validate_rsdp(struct 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 (acpi_tb_checksum((u8 *) rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0) {
+ return (AE_BAD_CHECKSUM);
+ }
+
+ /* Check extended checksum if table version >= 2 */
+
+ if ((rsdp->revision >= 2) &&
+ (acpi_tb_checksum((u8 *) rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0)) {
+ return (AE_BAD_CHECKSUM);
+ }
+
+ return (AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_find_root_pointer
+ *
+ * PARAMETERS: table_address - 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
+acpi_find_root_pointer(acpi_physical_address *table_address)
+{
+ u8 *table_ptr;
+ u8 *mem_rover;
+ u32 physical_address;
+
+ ACPI_FUNCTION_TRACE(acpi_find_root_pointer);
+
+ /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
+
+ table_ptr = acpi_os_map_memory((acpi_physical_address)
+ ACPI_EBDA_PTR_LOCATION,
+ ACPI_EBDA_PTR_LENGTH);
+ if (!table_ptr) {
+ 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(&physical_address, table_ptr);
+
+ /* Convert segment part to physical address */
+
+ physical_address <<= 4;
+ acpi_os_unmap_memory(table_ptr, ACPI_EBDA_PTR_LENGTH);
+
+ /* EBDA present? */
+
+ if (physical_address > 0x400) {
+ /*
+ * 1b) Search EBDA paragraphs (EBDA is required to be a
+ * minimum of 1K length)
+ */
+ table_ptr = acpi_os_map_memory((acpi_physical_address)
+ physical_address,
+ ACPI_EBDA_WINDOW_SIZE);
+ if (!table_ptr) {
+ ACPI_ERROR((AE_INFO,
+ "Could not map memory at 0x%8.8X for length %u",
+ physical_address, ACPI_EBDA_WINDOW_SIZE));
+
+ return_ACPI_STATUS(AE_NO_MEMORY);
+ }
+
+ mem_rover =
+ acpi_tb_scan_memory_for_rsdp(table_ptr,
+ ACPI_EBDA_WINDOW_SIZE);
+ acpi_os_unmap_memory(table_ptr, ACPI_EBDA_WINDOW_SIZE);
+
+ if (mem_rover) {
+
+ /* Return the physical address */
+
+ physical_address +=
+ (u32) ACPI_PTR_DIFF(mem_rover, table_ptr);
+
+ *table_address =
+ (acpi_physical_address)physical_address;
+ return_ACPI_STATUS(AE_OK);
+ }
+ }
+
+ /*
+ * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
+ */
+ table_ptr = acpi_os_map_memory((acpi_physical_address)
+ ACPI_HI_RSDP_WINDOW_BASE,
+ ACPI_HI_RSDP_WINDOW_SIZE);
+
+ if (!table_ptr) {
+ 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);
+ }
+
+ mem_rover =
+ acpi_tb_scan_memory_for_rsdp(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE);
+ acpi_os_unmap_memory(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE);
+
+ if (mem_rover) {
+
+ /* Return the physical address */
+
+ physical_address = (u32)
+ (ACPI_HI_RSDP_WINDOW_BASE +
+ ACPI_PTR_DIFF(mem_rover, table_ptr));
+
+ *table_address = (acpi_physical_address)physical_address;
+ 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(acpi_find_root_pointer)
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_tb_scan_memory_for_rsdp
+ *
+ * PARAMETERS: start_address - 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
+ *
+ ******************************************************************************/
+u8 *acpi_tb_scan_memory_for_rsdp(u8 *start_address, u32 length)
+{
+ acpi_status status;
+ u8 *mem_rover;
+ u8 *end_address;
+
+ ACPI_FUNCTION_TRACE(tb_scan_memory_for_rsdp);
+
+ end_address = start_address + length;
+
+ /* Search from given start address for the requested length */
+
+ for (mem_rover = start_address; mem_rover < end_address;
+ mem_rover += ACPI_RSDP_SCAN_STEP) {
+
+ /* The RSDP signature and checksum must both be correct */
+
+ status =
+ acpi_tb_validate_rsdp(ACPI_CAST_PTR
+ (struct acpi_table_rsdp, mem_rover));
+ 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",
+ mem_rover));
+ return_PTR(mem_rover);
+ }
+
+ /* 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",
+ start_address));
+ return_PTR(NULL);
+}