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Subject[PATCH] [8/12] x86_64: Use global flag to disable broken local apic timer on AMD CPUs.
Date

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>

---
arch/i386/kernel/apic.c | 8 +++-----
arch/i386/kernel/cpu/amd.c | 7 ++++++-
include/asm-i386/apic.h | 2 ++
include/asm-i386/cpufeature.h | 2 +-
4 files changed, 12 insertions(+), 7 deletions(-)
Index: linux/arch/i386/kernel/apic.c
===================================================================
--- linux.orig/arch/i386/kernel/apic.c
+++ linux/arch/i386/kernel/apic.c
@@ -61,8 +61,9 @@ static int enable_local_apic __initdata

/* 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);
@@ -370,9 +371,6 @@ 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
Index: linux/arch/i386/kernel/cpu/amd.c
===================================================================
--- linux.orig/arch/i386/kernel/cpu/amd.c
+++ linux/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_brok
}
return 0;
}
+#endif

int force_mwait __cpuinitdata;

@@ -282,8 +285,10 @@ static void __cpuinit init_amd(struct cp
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);
Index: linux/include/asm-i386/apic.h
===================================================================
--- linux.orig/include/asm-i386/apic.h
+++ linux/include/asm-i386/apic.h
@@ -116,6 +116,8 @@ extern void enable_NMI_through_LVT0 (voi
extern int timer_over_8254;
extern int local_apic_timer_c2_ok;

+extern int local_apic_timer_disabled;
+
#else /* !CONFIG_X86_LOCAL_APIC */
static inline void lapic_shutdown(void) { }

Index: linux/include/asm-i386/cpufeature.h
===================================================================
--- linux.orig/include/asm-i386/cpufeature.h
+++ linux/include/asm-i386/cpufeature.h
@@ -79,7 +79,7 @@
#define X86_FEATURE_ARCH_PERFMON (3*32+11) /* Intel Architectural PerfMon */
#define X86_FEATURE_PEBS (3*32+12) /* Precise-Event Based Sampling */
#define X86_FEATURE_BTS (3*32+13) /* Branch Trace Store */
-#define X86_FEATURE_LAPIC_TIMER_BROKEN (3*32+ 14) /* lapic timer broken in C1 */
+/* 14 free */
#define X86_FEATURE_SYNC_RDTSC (3*32+15) /* RDTSC synchronizes the CPU */
#define X86_FEATURE_REP_GOOD (3*32+16) /* rep microcode works well on this CPU */

-
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