i386: Use global flag to disable broken local apic timer on AMD CPUs.

The Averatec 2370 and some other Turion laptop BIOS seems to program the
ENABLE_C1E MSR inconsistently between cores. This confuses the lapic
use heuristics because when C1E is enabled anywhere it seems to affect
the complete chip.

Use a global flag instead of a per cpu flag to handle this.
If any CPU has C1E enabled disabled lapic use.

Thanks to Cal Peake for debugging.

Cc: tglx@linutronix.de
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 10 insertions, 7 deletions

diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index bfc6cb7..f9fff29 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -61,8 +61,9 @@ static int enable_local_apic __initdata = 0;
 
 /* Local APIC timer verification ok */
 static int local_apic_timer_verify_ok;
-/* Disable local APIC timer from the kernel commandline or via dmi quirk */
-static int local_apic_timer_disabled;
+/* Disable local APIC timer from the kernel commandline or via dmi quirk
+   or using CPU MSR check */
+int local_apic_timer_disabled;
 /* Local APIC timer works in C2 */
 int local_apic_timer_c2_ok;
 EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
@@ -370,12 +371,9 @@ void __init setup_boot_APIC_clock(void)
 	long delta, deltapm;
 	int pm_referenced = 0;
 
-	if (boot_cpu_has(X86_FEATURE_LAPIC_TIMER_BROKEN))
-		local_apic_timer_disabled = 1;
-
 	/*
 	 * The local apic timer can be disabled via the kernel
-	 * commandline or from the test above. Register the lapic
+	 * commandline or from the CPU detection code. Register the lapic
 	 * timer as a dummy clock event source on SMP systems, so the
 	 * broadcast mechanism is used. On UP systems simply ignore it.
 	 */
diff --git a/arch/i386/kernel/cpu/amd.c b/arch/i386/kernel/cpu/amd.c
index c7ba455..dcf6bbb 100644
--- a/arch/i386/kernel/cpu/amd.c
+++ b/arch/i386/kernel/cpu/amd.c
@@ -3,6 +3,7 @@
 #include <linux/mm.h>
 #include <asm/io.h>
 #include <asm/processor.h>
+#include <asm/apic.h>
 
 #include "cpu.h"
 
@@ -22,6 +23,7 @@
 extern void vide(void);
 __asm__(".align 4\nvide: ret");
 
+#ifdef CONFIG_X86_LOCAL_APIC
 #define ENABLE_C1E_MASK         0x18000000
 #define CPUID_PROCESSOR_SIGNATURE       1
 #define CPUID_XFAM              0x0ff00000
@@ -52,6 +54,7 @@ static __cpuinit int amd_apic_timer_broken(void)
         }
 	return 0;
 }
+#endif
 
 int force_mwait __cpuinitdata;
 
@@ -282,8 +285,10 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
 			num_cache_leaves = 3;
 	}
 
+#ifdef CONFIG_X86_LOCAL_APIC
 	if (amd_apic_timer_broken())
-		set_bit(X86_FEATURE_LAPIC_TIMER_BROKEN, c->x86_capability);
+		local_apic_timer_disabled = 1;
+#endif
 
 	if (c->x86 == 0x10 && !force_mwait)
 		clear_bit(X86_FEATURE_MWAIT, c->x86_capability);