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-rw-r--r--drivers/acpi/tables/tbutils.c71
1 files changed, 71 insertions, 0 deletions
diff --git a/drivers/acpi/tables/tbutils.c b/drivers/acpi/tables/tbutils.c
index 1da64b4518c..8cc9492ffbf 100644
--- a/drivers/acpi/tables/tbutils.c
+++ b/drivers/acpi/tables/tbutils.c
@@ -51,6 +51,65 @@ ACPI_MODULE_NAME("tbutils")
static acpi_physical_address
acpi_tb_get_root_table_entry(u8 * table_entry,
acpi_native_uint table_entry_size);
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_tb_check_xsdt
+ *
+ * PARAMETERS: address - Pointer to the XSDT
+ *
+ * RETURN: status
+ * AE_OK - XSDT is okay
+ * AE_NO_MEMORY - can't map XSDT
+ * AE_INVALID_TABLE_LENGTH - invalid table length
+ * AE_NULL_ENTRY - XSDT has NULL entry
+ *
+ * DESCRIPTION: validate XSDT
+******************************************************************************/
+
+static acpi_status
+acpi_tb_check_xsdt(acpi_physical_address address)
+{
+ struct acpi_table_header *table;
+ u32 length;
+ u64 xsdt_entry_address;
+ u8 *table_entry;
+ u32 table_count;
+ int i;
+
+ table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));
+ if (!table)
+ return AE_NO_MEMORY;
+
+ length = table->length;
+ acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
+ if (length < sizeof(struct acpi_table_header))
+ return AE_INVALID_TABLE_LENGTH;
+
+ table = acpi_os_map_memory(address, length);
+ if (!table)
+ return AE_NO_MEMORY;
+
+ /* Calculate the number of tables described in XSDT */
+ table_count =
+ (u32) ((table->length -
+ sizeof(struct acpi_table_header)) / sizeof(u64));
+ table_entry =
+ ACPI_CAST_PTR(u8, table) + sizeof(struct acpi_table_header);
+ for (i = 0; i < table_count; i++) {
+ ACPI_MOVE_64_TO_64(&xsdt_entry_address, table_entry);
+ if (!xsdt_entry_address) {
+ /* XSDT has NULL entry */
+ break;
+ }
+ table_entry += sizeof(u64);
+ }
+ acpi_os_unmap_memory(table, length);
+
+ if (i < table_count)
+ return AE_NULL_ENTRY;
+ else
+ return AE_OK;
+}
/*******************************************************************************
*
@@ -341,6 +400,7 @@ acpi_tb_parse_root_table(acpi_physical_address rsdp_address, u8 flags)
u32 table_count;
struct acpi_table_header *table;
acpi_physical_address address;
+ acpi_physical_address rsdt_address;
u32 length;
u8 *table_entry;
acpi_status status;
@@ -369,6 +429,8 @@ acpi_tb_parse_root_table(acpi_physical_address rsdp_address, u8 flags)
*/
address = (acpi_physical_address) rsdp->xsdt_physical_address;
table_entry_size = sizeof(u64);
+ rsdt_address = (acpi_physical_address)
+ rsdp->rsdt_physical_address;
} else {
/* Root table is an RSDT (32-bit physical addresses) */
@@ -382,6 +444,15 @@ acpi_tb_parse_root_table(acpi_physical_address rsdp_address, u8 flags)
*/
acpi_os_unmap_memory(rsdp, sizeof(struct acpi_table_rsdp));
+ if (table_entry_size == sizeof(u64)) {
+ if (acpi_tb_check_xsdt(address) == AE_NULL_ENTRY) {
+ /* XSDT has NULL entry, RSDT is used */
+ address = rsdt_address;
+ table_entry_size = sizeof(u32);
+ ACPI_WARNING((AE_INFO, "BIOS XSDT has NULL entry,"
+ "using RSDT"));
+ }
+ }
/* Map the RSDT/XSDT table header to get the full table length */
table = acpi_os_map_memory(address, sizeof(struct acpi_table_header));