ACPICA: Fail AcpiEnable if ACPI tables not loaded.

AcpiEnable will now fail if all of the required ACPI tables are not
loaded (FADT, FACS, DSDT). BZ 477

Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

3 files changed, 33 insertions, 0 deletions

diff --git a/drivers/acpi/events/evxfevnt.c b/drivers/acpi/events/evxfevnt.c
index a3d148e4d39f..4eab4f5a1004 100644
--- a/drivers/acpi/events/evxfevnt.c
+++ b/drivers/acpi/events/evxfevnt.c
@@ -65,6 +65,14 @@ acpi_status acpi_enable(void)
 
         ACPI_FUNCTION_TRACE(acpi_enable);
 
+        /* ACPI tables must be present */
+
+        if (!acpi_tb_tables_loaded()) {
+                return_ACPI_STATUS(AE_NO_ACPI_TABLES);
+        }
+
+        /* Check current mode */
+
         if (acpi_hw_get_mode() == ACPI_SYS_MODE_ACPI) {
                 ACPI_DEBUG_PRINT((ACPI_DB_INIT,
                                   "System is already in ACPI mode\n"));
diff --git a/drivers/acpi/tables/tbutils.c b/drivers/acpi/tables/tbutils.c
index 0cb743962faf..0874ab299784 100644
--- a/drivers/acpi/tables/tbutils.c
+++ b/drivers/acpi/tables/tbutils.c
@@ -54,6 +54,29 @@ acpi_tb_get_root_table_entry(u8 * table_entry,
 
 /*******************************************************************************
  *
+ * FUNCTION:    acpi_tb_tables_loaded
+ *
+ * PARAMETERS:  None
+ *
+ * RETURN:      TRUE if required ACPI tables are loaded
+ *
+ * DESCRIPTION: Determine if the minimum required ACPI tables are present
+ *              (FADT, FACS, DSDT)
+ *
+ ******************************************************************************/
+
+u8 acpi_tb_tables_loaded(void)
+{
+
+        if (acpi_gbl_root_table_list.count >= 3) {
+                return (TRUE);
+        }
+
+        return (FALSE);
+}
+
+/*******************************************************************************
+ *
  * FUNCTION:    acpi_tb_print_table_header
  *
  * PARAMETERS:  Address             - Table physical address
diff --git a/include/acpi/actables.h b/include/acpi/actables.h
index 5ef1b6939370..e7efb8a03a9c 100644
--- a/include/acpi/actables.h
+++ b/include/acpi/actables.h
@@ -97,6 +97,8 @@ void acpi_tb_set_table_loaded_flag(acpi_native_uint table_index, u8 is_loaded);
 /*
  * tbutils - table manager utilities
  */
+u8 acpi_tb_tables_loaded(void);
+
 void
 acpi_tb_print_table_header(acpi_physical_address address,
                            struct acpi_table_header *header);