x86, clockevents: add C1E aware idle function

C1E on AMD machines is like C3 but without control from the OS. Up to
now we disabled the local apic timer for those machines as it stops
when the CPU goes into C1E. This excludes those machines from high
resolution timers / dynamic ticks, which hurts especially X2 based
laptops.

The current boot time C1E detection has another, more serious flaw
as well: some BIOSes do not enable C1E until the ACPI processor module
is loaded. This causes systems to stop working after that point.

To work nicely with C1E enabled machines we use a separate idle
function, which checks on idle entry whether C1E was enabled in the
Interrupt Pending Message MSR. This allows us to do timer broadcasting
for C1E and covers the late enablement of C1E as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 0 insertions, 30 deletions

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index e76b49e7a916..acc891ae5901 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -24,31 +24,6 @@
 extern void vide(void);
 __asm__(".align 4\nvide: ret");
 
-#ifdef CONFIG_X86_LOCAL_APIC
-
-/* AMD systems with C1E don't have a working lAPIC timer. Check for that. */
-static __cpuinit int amd_apic_timer_broken(struct cpuinfo_x86 *c)
-{
-	u32 lo, hi;
-
-	if (c->x86 < 0x0F)
-		return 0;
-
-	/* Family 0x0f models < rev F do not have this MSR */
-	if (c->x86 == 0x0f && c->x86_model < 0x40)
-		return 0;
-
-	rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi);
-	if (lo & K8_INTP_C1E_ACTIVE_MASK) {
-		if (smp_processor_id() != boot_cpu_physical_apicid)
-			printk(KERN_INFO "AMD C1E detected late. "
-			       "Force timer broadcast.\n");
-		return 1;
-	}
-	return 0;
-}
-#endif
-
 int force_mwait __cpuinitdata;
 
 static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
@@ -285,11 +260,6 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c)
 			num_cache_leaves = 3;
 	}
 
-#ifdef CONFIG_X86_LOCAL_APIC
-	if (amd_apic_timer_broken(c))
-		local_apic_timer_disabled = 1;
-#endif
-
 	/* K6s reports MCEs but don't actually have all the MSRs */
 	if (c->x86 < 6)
 		clear_cpu_cap(c, X86_FEATURE_MCE);