Merge branches 'x86/apic', 'x86/cleanups', 'x86/cpufeature', 'x86/crashdump', 'x86...

[linux-2.6-omap-h63xx.git] / arch / x86 / kernel / tsc_sync.c

diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c
index 9ffb01c31c40a8c9083e9949d065a442a62f46b7..bf36328f6ef9289c4b1a1a7d0ffd9c67878f3f32 100644 (file)
--- a/arch/x86/kernel/tsc_sync.c
+++ b/arch/x86/kernel/tsc_sync.c
@@ -46,7 +46,9 @@ static __cpuinit void check_tsc_warp(void)
        cycles_t start, now, prev, end;
        int i;
 
+       rdtsc_barrier();
        start = get_cycles();
+       rdtsc_barrier();
        /*
         * The measurement runs for 20 msecs:
         */
@@ -61,7 +63,9 @@ static __cpuinit void check_tsc_warp(void)
                 */
                __raw_spin_lock(&sync_lock);
                prev = last_tsc;
+               rdtsc_barrier();
                now = get_cycles();
+               rdtsc_barrier();
                last_tsc = now;
                __raw_spin_unlock(&sync_lock);
 
@@ -108,6 +112,12 @@ void __cpuinit check_tsc_sync_source(int cpu)
        if (unsynchronized_tsc())
                return;
 
+       if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE)) {
+               printk(KERN_INFO
+                      "Skipping synchronization checks as TSC is reliable.\n");
+               return;
+       }
+
        printk(KERN_INFO "checking TSC synchronization [CPU#%d -> CPU#%d]:",
                          smp_processor_id(), cpu);
 
@@ -161,7 +171,7 @@ void __cpuinit check_tsc_sync_target(void)
 {
        int cpus = 2;
 
-       if (unsynchronized_tsc())
+       if (unsynchronized_tsc() || boot_cpu_has(X86_FEATURE_TSC_RELIABLE))
                return;
 
        /*