4 files changed, 96 insertions, 11 deletions

diff --git a/drivers/acpi/tables/tbinstal.c b/drivers/acpi/tables/tbinstal.c
index 2ad72f204551..698799901f55 100644
--- a/drivers/acpi/tables/tbinstal.c
+++ b/drivers/acpi/tables/tbinstal.c
@@ -124,9 +124,7 @@ acpi_tb_match_signature (
  *
  * RETURN:      Status
  *
- * DESCRIPTION: Load and validate all tables other than the RSDT.  The RSDT must
- *              already be loaded and validated.
- *              Install the table into the global data structs.
+ * DESCRIPTION: Install the table into the global data structures.
  *
  ******************************************************************************/
 
@@ -136,6 +134,7 @@ acpi_tb_install_table (
 {
         acpi_status                     status;
 
+
         ACPI_FUNCTION_TRACE ("tb_install_table");
 
 
@@ -143,22 +142,33 @@ acpi_tb_install_table (
 
         status = acpi_ut_acquire_mutex (ACPI_MTX_TABLES);
         if (ACPI_FAILURE (status)) {
-                ACPI_REPORT_ERROR (("Could not acquire table mutex for [%4.4s], %s\n",
-                        table_info->pointer->signature, acpi_format_exception (status)));
+                ACPI_REPORT_ERROR (("Could not acquire table mutex, %s\n",
+                        acpi_format_exception (status)));
                 return_ACPI_STATUS (status);
         }
 
+        /*
+         * Ignore a table that is already installed. For example, some BIOS
+         * ASL code will repeatedly attempt to load the same SSDT.
+         */
+        status = acpi_tb_is_table_installed (table_info);
+        if (ACPI_FAILURE (status)) {
+                goto unlock_and_exit;
+        }
+
         /* Install the table into the global data structure */
 
         status = acpi_tb_init_table_descriptor (table_info->type, table_info);
         if (ACPI_FAILURE (status)) {
-                ACPI_REPORT_ERROR (("Could not install ACPI table [%4.4s], %s\n",
+                ACPI_REPORT_ERROR (("Could not install table [%4.4s], %s\n",
                         table_info->pointer->signature, acpi_format_exception (status)));
         }
 
         ACPI_DEBUG_PRINT ((ACPI_DB_INFO, "%s located at %p\n",
                 acpi_gbl_table_data[table_info->type].name, table_info->pointer));
 
+
+unlock_and_exit:
         (void) acpi_ut_release_mutex (ACPI_MTX_TABLES);
         return_ACPI_STATUS (status);
 }
diff --git a/drivers/acpi/tables/tbutils.c b/drivers/acpi/tables/tbutils.c
index e69d01d443d2..6fc1e36e6042 100644
--- a/drivers/acpi/tables/tbutils.c
+++ b/drivers/acpi/tables/tbutils.c
@@ -61,6 +61,67 @@ acpi_tb_handle_to_object (
 
 /*******************************************************************************
  *
+ * FUNCTION:    acpi_tb_is_table_installed
+ *
+ * PARAMETERS:  new_table_desc      - Descriptor for new table being installed
+ *
+ * RETURN:      Status - AE_ALREADY_EXISTS if the table is already installed
+ *
+ * DESCRIPTION: Determine if an ACPI table is already installed
+ *
+ * MUTEX:       Table data structures should be locked
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_tb_is_table_installed (
+        struct acpi_table_desc          *new_table_desc)
+{
+        struct acpi_table_desc          *table_desc;
+
+
+        ACPI_FUNCTION_TRACE ("tb_is_table_installed");
+
+
+        /* Get the list descriptor and first table descriptor */
+
+        table_desc = acpi_gbl_table_lists[new_table_desc->type].next;
+
+        /* Examine all installed tables of this type */
+
+        while (table_desc) {
+                /* Compare Revision and oem_table_id */
+
+                if ((table_desc->loaded_into_namespace) &&
+                        (table_desc->pointer->revision ==
+                                        new_table_desc->pointer->revision) &&
+                        (!ACPI_MEMCMP (table_desc->pointer->oem_table_id,
+                                        new_table_desc->pointer->oem_table_id, 8))) {
+                        /* This table is already installed */
+
+                        ACPI_DEBUG_PRINT ((ACPI_DB_TABLES,
+                                "Table [%4.4s] already installed: Rev %X oem_table_id [%8.8s]\n",
+                                new_table_desc->pointer->signature,
+                                new_table_desc->pointer->revision,
+                                new_table_desc->pointer->oem_table_id));
+
+                        new_table_desc->owner_id    = table_desc->owner_id;
+                        new_table_desc->installed_desc = table_desc;
+
+                        return_ACPI_STATUS (AE_ALREADY_EXISTS);
+                }
+
+                /* Get next table on the list */
+
+                table_desc = table_desc->next;
+        }
+
+        return_ACPI_STATUS (AE_OK);
+}
+
+
+/*******************************************************************************
+ *
  * FUNCTION:    acpi_tb_validate_table_header
  *
  * PARAMETERS:  table_header        - Logical pointer to the table
@@ -157,7 +218,7 @@ acpi_tb_verify_table_checksum (
 
         /* Compute the checksum on the table */
 
-        checksum = acpi_tb_checksum (table_header, table_header->length);
+        checksum = acpi_tb_generate_checksum (table_header, table_header->length);
 
         /* Return the appropriate exception */
 
@@ -175,7 +236,7 @@ acpi_tb_verify_table_checksum (
 
 /*******************************************************************************
  *
- * FUNCTION:    acpi_tb_checksum
+ * FUNCTION:    acpi_tb_generate_checksum
  *
  * PARAMETERS:  Buffer              - Buffer to checksum
  *              Length              - Size of the buffer
@@ -187,7 +248,7 @@ acpi_tb_verify_table_checksum (
  ******************************************************************************/
 
 u8
-acpi_tb_checksum (
+acpi_tb_generate_checksum (
         void                            *buffer,
         u32                             length)
 {
diff --git a/drivers/acpi/tables/tbxface.c b/drivers/acpi/tables/tbxface.c
index ca2dbdd23ed3..e18a05d1b9b3 100644
--- a/drivers/acpi/tables/tbxface.c
+++ b/drivers/acpi/tables/tbxface.c
@@ -182,10 +182,23 @@ acpi_load_table (
                 return_ACPI_STATUS (status);
         }
 
+        /* Check signature for a valid table type */
+
+        status = acpi_tb_recognize_table (&table_info, ACPI_TABLE_ALL);
+        if (ACPI_FAILURE (status)) {
+                return_ACPI_STATUS (status);
+        }
+
         /* Install the new table into the local data structures */
 
         status = acpi_tb_install_table (&table_info);
         if (ACPI_FAILURE (status)) {
+                if (status == AE_ALREADY_EXISTS) {
+                        /* Table already exists, no error */
+
+                        status = AE_OK;
+                }
+
                 /* Free table allocated by acpi_tb_get_table_body */
 
                 acpi_tb_delete_single_table (&table_info);
@@ -261,6 +274,7 @@ acpi_unload_table (
                  * simply a position within the hierarchy
                  */
                 acpi_ns_delete_namespace_by_owner (table_desc->owner_id);
+                acpi_ut_release_owner_id (&table_desc->owner_id);
                 table_desc = table_desc->next;
         }
 
diff --git a/drivers/acpi/tables/tbxfroot.c b/drivers/acpi/tables/tbxfroot.c
index abb4c9346560..87dccdda9ae2 100644
--- a/drivers/acpi/tables/tbxfroot.c
+++ b/drivers/acpi/tables/tbxfroot.c
@@ -93,14 +93,14 @@ acpi_tb_validate_rsdp (
 
         /* Check the standard checksum */
 
-        if (acpi_tb_checksum (rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0) {
+        if (acpi_tb_generate_checksum (rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0) {
                 return (AE_BAD_CHECKSUM);
         }
 
         /* Check extended checksum if table version >= 2 */
 
         if ((rsdp->revision >= 2) &&
-                (acpi_tb_checksum (rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0)) {
+                (acpi_tb_generate_checksum (rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0)) {
                 return (AE_BAD_CHECKSUM);
         }