4 files changed, 50 insertions, 46 deletions

diff --git a/drivers/acpi/acpica/acglobal.h b/drivers/acpi/acpica/acglobal.h
index ddb40f5c68fc..634fb0785e7e 100644
--- a/drivers/acpi/acpica/acglobal.h
+++ b/drivers/acpi/acpica/acglobal.h
@@ -371,7 +371,6 @@ ACPI_EXTERN char *acpi_gbl_db_buffer;
 ACPI_EXTERN char *acpi_gbl_db_filename;
 ACPI_EXTERN u32 acpi_gbl_db_debug_level;
 ACPI_EXTERN u32 acpi_gbl_db_console_debug_level;
-ACPI_EXTERN struct acpi_table_header *acpi_gbl_db_table_ptr;
 ACPI_EXTERN struct acpi_namespace_node *acpi_gbl_db_scope_node;
 
 /*
diff --git a/drivers/acpi/acpica/tbutils.c b/drivers/acpi/acpica/tbutils.c
index 22ce48985720..e285bedbb989 100644
--- a/drivers/acpi/acpica/tbutils.c
+++ b/drivers/acpi/acpica/tbutils.c
@@ -287,7 +287,10 @@ u8 acpi_tb_checksum(u8 *buffer, u32 length)
  *
  * RETURN:      None
  *
- * DESCRIPTION: Install an ACPI table into the global data structure.
+ * DESCRIPTION: Install an ACPI table into the global data structure. The
+ *              table override mechanism is implemented here to allow the host
+ *              OS to replace any table before it is installed in the root
+ *              table array.
  *
  ******************************************************************************/
 
@@ -295,7 +298,10 @@ void
 acpi_tb_install_table(acpi_physical_address address,
                       u8 flags, char *signature, u32 table_index)
 {
-        struct acpi_table_header *table;
+        acpi_status status;
+        struct acpi_table_header *table_to_install;
+        struct acpi_table_header *mapped_table;
+        struct acpi_table_header *override_table = NULL;
 
         if (!address) {
                 ACPI_ERROR((AE_INFO,
@@ -306,41 +312,68 @@ acpi_tb_install_table(acpi_physical_address address,
 
         /* Map just the table header */
 
-        table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
-        if (!table) {
+        mapped_table =
+            acpi_os_map_memory(address, sizeof(struct acpi_table_header));
+        if (!mapped_table) {
                 return;
         }
 
-        /* If a particular signature is expected, signature must match */
+        /* If a particular signature is expected (DSDT/FACS), it must match */
 
-        if (signature && !ACPI_COMPARE_NAME(table->signature, signature)) {
+        if (signature && !ACPI_COMPARE_NAME(mapped_table->signature, signature)) {
                 ACPI_ERROR((AE_INFO,
-                            "Invalid signature 0x%X for ACPI table [%s]",
-                            *ACPI_CAST_PTR(u32, table->signature), signature));
+                            "Invalid signature 0x%X for ACPI table, expected [%s]",
+                            *ACPI_CAST_PTR(u32, mapped_table->signature),
+                            signature));
                 goto unmap_and_exit;
         }
 
+        /*
+         * ACPI Table Override:
+         *
+         * Before we install the table, let the host OS override it with a new
+         * one if desired. Any table within the RSDT/XSDT can be replaced,
+         * including the DSDT which is pointed to by the FADT.
+         */
+        status = acpi_os_table_override(mapped_table, &override_table);
+        if (ACPI_SUCCESS(status) && override_table) {
+                ACPI_INFO((AE_INFO,
+                           "%4.4s @ 0x%p Table override, replaced with:",
+                           mapped_table->signature, ACPI_CAST_PTR(void,
+                                                                  address)));
+
+                acpi_gbl_root_table_list.tables[table_index].pointer =
+                    override_table;
+                flags = ACPI_TABLE_ORIGIN_OVERRIDE;
+                address = ACPI_PTR_TO_PHYSADDR(override_table);
+
+                table_to_install = override_table;
+        } else {
+                table_to_install = mapped_table;
+        }
+
         /* Initialize the table entry */
 
         acpi_gbl_root_table_list.tables[table_index].address = address;
-        acpi_gbl_root_table_list.tables[table_index].length = table->length;
+        acpi_gbl_root_table_list.tables[table_index].length =
+            table_to_install->length;
         acpi_gbl_root_table_list.tables[table_index].flags = flags;
 
         ACPI_MOVE_32_TO_32(&
                            (acpi_gbl_root_table_list.tables[table_index].
-                            signature), table->signature);
+                            signature), table_to_install->signature);
 
-        acpi_tb_print_table_header(address, table);
+        acpi_tb_print_table_header(address, table_to_install);
 
         if (table_index == ACPI_TABLE_INDEX_DSDT) {
 
                 /* Global integer width is based upon revision of the DSDT */
 
-                acpi_ut_set_integer_width(table->revision);
+                acpi_ut_set_integer_width(table_to_install->revision);
         }
 
       unmap_and_exit:
-        acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
+        acpi_os_unmap_memory(mapped_table, sizeof(struct acpi_table_header));
 }
 
 /*******************************************************************************
diff --git a/drivers/acpi/acpica/tbxface.c b/drivers/acpi/acpica/tbxface.c
index c3e841f3cde9..f3f95e386334 100644
--- a/drivers/acpi/acpica/tbxface.c
+++ b/drivers/acpi/acpica/tbxface.c
@@ -491,7 +491,6 @@ ACPI_EXPORT_SYMBOL(acpi_get_table_by_index)
 static acpi_status acpi_tb_load_namespace(void)
 {
         acpi_status status;
-        struct acpi_table_header *table;
         u32 i;
 
         ACPI_FUNCTION_TRACE(tb_load_namespace);
@@ -515,41 +514,13 @@ static acpi_status acpi_tb_load_namespace(void)
                 goto unlock_and_exit;
         }
 
-        /*
-         * Find DSDT table
-         */
-        status =
-            acpi_os_table_override(acpi_gbl_root_table_list.
-                                   tables[ACPI_TABLE_INDEX_DSDT].pointer,
-                                   &table);
-        if (ACPI_SUCCESS(status) && table) {
-                /*
-                 * DSDT table has been found
-                 */
-                acpi_tb_delete_table(&acpi_gbl_root_table_list.
-                                     tables[ACPI_TABLE_INDEX_DSDT]);
-                acpi_gbl_root_table_list.tables[ACPI_TABLE_INDEX_DSDT].pointer =
-                    table;
-                acpi_gbl_root_table_list.tables[ACPI_TABLE_INDEX_DSDT].length =
-                    table->length;
-                acpi_gbl_root_table_list.tables[ACPI_TABLE_INDEX_DSDT].flags =
-                    ACPI_TABLE_ORIGIN_UNKNOWN;
-
-                ACPI_INFO((AE_INFO, "Table DSDT replaced by host OS"));
-                acpi_tb_print_table_header(0, table);
-
-                if (no_auto_ssdt == 0) {
-                        printk(KERN_WARNING "ACPI: DSDT override uses original SSDTs unless \"acpi_no_auto_ssdt\"\n");
-                }
-        }
+        /* A valid DSDT is required */
 
         status =
             acpi_tb_verify_table(&acpi_gbl_root_table_list.
                                  tables[ACPI_TABLE_INDEX_DSDT]);
         if (ACPI_FAILURE(status)) {
 
-                /* A valid DSDT is required */
-
                 status = AE_NO_ACPI_TABLES;
                 goto unlock_and_exit;
         }
diff --git a/include/acpi/actbl.h b/include/acpi/actbl.h
index bf8d4cfd8cf5..1f3dfdb1b370 100644
--- a/include/acpi/actbl.h
+++ b/include/acpi/actbl.h
@@ -310,8 +310,9 @@ struct acpi_table_desc {
 #define ACPI_TABLE_ORIGIN_UNKNOWN       (0)
 #define ACPI_TABLE_ORIGIN_MAPPED        (1)
 #define ACPI_TABLE_ORIGIN_ALLOCATED     (2)
-#define ACPI_TABLE_ORIGIN_MASK          (3)
-#define ACPI_TABLE_IS_LOADED            (4)
+#define ACPI_TABLE_ORIGIN_OVERRIDE      (4)
+#define ACPI_TABLE_ORIGIN_MASK          (7)
+#define ACPI_TABLE_IS_LOADED            (8)
 
 /*
  * Get the remaining ACPI tables