[PATCH] x86_64: Only do the clustered systems have unsynchronized TSC assumption on IBM systems
Big Unisys systems have multiple clusters too, but they have an
synchronized TSC.
I'm using the SMBIOS to check for vendor == IBM.
Cc: Chris McDermott <lcm@us.ibm.com>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@unisys.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index 79577f0..8309a7b 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -44,9 +44,6 @@
extern int gsi_irq_sharing(int gsi);
#include <asm/proto.h>
-static inline int acpi_madt_oem_check(char *oem_id, char *oem_table_id) { return 0; }
-
-
#else /* X86 */
#ifdef CONFIG_X86_LOCAL_APIC
diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index e5b14c5..d70605e 100644
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -962,12 +962,14 @@
irq_exit();
}
+int __initdata unsync_tsc_on_multicluster;
+
/*
* oem_force_hpet_timer -- force HPET mode for some boxes.
*
* Thus far, the major user of this is IBM's Summit2 series:
*
- * Clustered boxes may have unsynced TSC problems if they are
+ * Some clustered boxes may have unsynced TSC problems if they are
* multi-chassis. Use available data to take a good guess.
* If in doubt, go HPET.
*/
@@ -977,6 +979,11 @@
unsigned id;
DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS);
+ /* Only do this check on IBM machines - big Unisys systems
+ use multiple clusters too, but have synchronized TSC */
+ if (!unsync_tsc_on_multicluster)
+ return 0;
+
bitmap_zero(clustermap, NUM_APIC_CLUSTERS);
for (i = 0; i < NR_CPUS; i++) {
diff --git a/include/asm-x86_64/acpi.h b/include/asm-x86_64/acpi.h
index aa1c7b2..e2b9923 100644
--- a/include/asm-x86_64/acpi.h
+++ b/include/asm-x86_64/acpi.h
@@ -164,6 +164,20 @@
extern int acpi_skip_timer_override;
+extern int unsync_tsc_on_multicluster;
+
+static inline int acpi_madt_oem_check(char *oem, char *productid)
+{
+ /* Copied from i386. Probably has too many entries. */
+ if (!strncmp(oem, "IBM ENSW", 8) &&
+ (!strncmp(productid, "VIGIL SMP", 9)
+ || !strncmp(productid, "EXA", 3)
+ || !strncmp(productid, "RUTHLESS SMP", 12))) {
+ unsync_tsc_on_multicluster = 1;
+ }
+ return 0;
+}
+
#endif /*__KERNEL__*/
#endif /*_ASM_ACPI_H*/