ACPI: Store SRAT table revision

In SRAT v1, we had 8bit proximity domain (PXM) fields; SRAT v2 provides
32bits for these. The new fields were reserved before.
According to the ACPI spec, the OS must disregrard reserved fields.
In order to know whether or not, we must know what version the SRAT
table has.

This patch stores the SRAT table revision for later consumption
by arch specific __init functions.
Signed-off-by: Kurt Garloff <kurt@garloff.de>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/numa.c

@@ -45,6 +45,8 @@ static int pxm_to_node_map[MAX_PXM_DOMAINS]
 static int node_to_pxm_map[MAX_NUMNODES]
 			= { [0 ... MAX_NUMNODES - 1] = PXM_INVAL };
 
+unsigned char acpi_srat_revision __initdata;
+
 int pxm_to_node(int pxm)
 {
 	if (pxm < 0)
@@ -255,9 +257,13 @@ acpi_parse_memory_affinity(struct acpi_subtable_header * header,
 
 static int __init acpi_parse_srat(struct acpi_table_header *table)
 {
+	struct acpi_table_srat *srat;
 	if (!table)
 		return -EINVAL;
 
+	srat = (struct acpi_table_srat *)table;
+	acpi_srat_revision = srat->header.revision;
+
 	/* Real work done in acpi_table_parse_srat below. */
 
 	return 0;

include/acpi/acpi_numa.h

@@ -15,6 +15,7 @@ extern int pxm_to_node(int);
 extern int node_to_pxm(int);
 extern void __acpi_map_pxm_to_node(int, int);
 extern int acpi_map_pxm_to_node(int);
+extern unsigned char acpi_srat_revision;
 
 #endif				/* CONFIG_ACPI_NUMA */
 #endif				/* __ACP_NUMA_H */