1 files changed, 50 insertions, 40 deletions

diff --git a/arch/x86/kernel/apic_64.c b/arch/x86/kernel/apic_64.c
index 2c2807abe1d..b0237caff71 100644
--- a/arch/x86/kernel/apic_64.c
+++ b/arch/x86/kernel/apic_64.c
@@ -857,25 +857,12 @@ static void __setup_APIC_LVTT(unsigned int clocks, int oneshot, int irqen)
 
 static void setup_APIC_timer(void)
 {
-        unsigned long flags;
-        int irqen;
+        struct clock_event_device *levt = &__get_cpu_var(lapic_events);
 
-        local_irq_save(flags);
+        memcpy(levt, &lapic_clockevent, sizeof(*levt));
+        levt->cpumask = cpumask_of_cpu(smp_processor_id());
 
-        irqen = ! cpu_isset(smp_processor_id(),
-                            timer_interrupt_broadcast_ipi_mask);
-        __setup_APIC_LVTT(calibration_result, 0, irqen);
-        /* Turn off PIT interrupt if we use APIC timer as main timer.
-           Only works with the PM timer right now
-           TBD fix it for HPET too. */
-        if ((pmtmr_ioport != 0) &&
-                smp_processor_id() == boot_cpu_id &&
-                apic_runs_main_timer == 1 &&
-                !cpu_isset(boot_cpu_id, timer_interrupt_broadcast_ipi_mask)) {
-                stop_timer_interrupt();
-                apic_runs_main_timer++;
-        }
-        local_irq_restore(flags);
+        clockevents_register_device(levt);
 }
 
 /*
@@ -950,18 +937,34 @@ static void __init calibrate_APIC_clock(void)
 
 void __init setup_boot_APIC_clock (void)
 {
+        /*
+         * The local apic timer can be disabled via the kernel commandline.
+         * 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.
+         */
         if (disable_apic_timer) {
                 printk(KERN_INFO "Disabling APIC timer\n");
+                /* No broadcast on UP ! */
+                if (num_possible_cpus() > 1)
+                        setup_APIC_timer();
                 return;
         }
 
         printk(KERN_INFO "Using local APIC timer interrupts.\n");
-        using_apic_timer = 1;
-
         calibrate_APIC_clock();
+
         /*
-         * Now set up the timer for real.
+         * If nmi_watchdog is set to IO_APIC, we need the
+         * PIT/HPET going.  Otherwise register lapic as a dummy
+         * device.
          */
+        if (nmi_watchdog != NMI_IO_APIC)
+                lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
+        else
+                printk(KERN_WARNING "APIC timer registered as dummy,"
+                       " due to nmi_watchdog=1!\n");
+
         setup_APIC_timer();
 }
 
@@ -1073,22 +1076,34 @@ void setup_APIC_extended_lvt(unsigned char lvt_off, unsigned char vector,
 
 void smp_local_timer_interrupt(void)
 {
-        profile_tick(CPU_PROFILING);
-#ifdef CONFIG_SMP
-        update_process_times(user_mode(get_irq_regs()));
-#endif
-        if (apic_runs_main_timer > 1 && smp_processor_id() == boot_cpu_id)
-                main_timer_handler();
+        int cpu = smp_processor_id();
+        struct clock_event_device *evt = &per_cpu(lapic_events, cpu);
+
         /*
-         * We take the 'long' return path, and there every subsystem
-         * grabs the appropriate locks (kernel lock/ irq lock).
-         *
-         * We might want to decouple profiling from the 'long path',
-         * and do the profiling totally in assembly.
+         * Normally we should not be here till LAPIC has been initialized but
+         * in some cases like kdump, its possible that there is a pending LAPIC
+         * timer interrupt from previous kernel's context and is delivered in
+         * new kernel the moment interrupts are enabled.
          *
-         * Currently this isn't too much of an issue (performance wise),
-         * we can take more than 100K local irqs per second on a 100 MHz P5.
+         * Interrupts are enabled early and LAPIC is setup much later, hence
+         * its possible that when we get here evt->event_handler is NULL.
+         * Check for event_handler being NULL and discard the interrupt as
+         * spurious.
          */
+        if (!evt->event_handler) {
+                printk(KERN_WARNING
+                       "Spurious LAPIC timer interrupt on cpu %d\n", cpu);
+                /* Switch it off */
+                lapic_timer_setup(CLOCK_EVT_MODE_SHUTDOWN, evt);
+                return;
+        }
+
+        /*
+         * the NMI deadlock-detector uses this.
+         */
+        add_pda(apic_timer_irqs, 1);
+
+        evt->event_handler(evt);
 }
 
 /*
@@ -1104,11 +1119,6 @@ void smp_apic_timer_interrupt(struct pt_regs *regs)
         struct pt_regs *old_regs = set_irq_regs(regs);
 
         /*
-         * the NMI deadlock-detector uses this.
-         */
-        add_pda(apic_timer_irqs, 1);
-
-        /*
          * NOTE! We'd better ACK the irq immediately,
          * because timer handling can be slow.
          */
@@ -1291,7 +1301,7 @@ static __init int setup_noapictimer(char *str)
 static __init int setup_apicmaintimer(char *str)
 {
         apic_runs_main_timer = 1;
-        nohpet = 1;
+
         return 1;
 }
 __setup("apicmaintimer", setup_apicmaintimer);
@@ -1307,7 +1317,7 @@ static __init int setup_apicpmtimer(char *s)
 {
         apic_calibrate_pmtmr = 1;
         notsc_setup(NULL);
-        return setup_apicmaintimer(NULL);
+        return 0;
 }
 __setup("apicpmtimer", setup_apicpmtimer);