1 files changed, 42 insertions, 24 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 52fa56399a50..f98d84caf94c 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -186,7 +186,7 @@ static struct resource lapic_resource = {
         .flags = IORESOURCE_MEM | IORESOURCE_BUSY,
 };
 
-static unsigned int calibration_result;
+unsigned int lapic_timer_frequency = 0;
 
 static void apic_pm_activate(void);
 
@@ -454,7 +454,7 @@ static void lapic_timer_setup(enum clock_event_mode mode,
         switch (mode) {
         case CLOCK_EVT_MODE_PERIODIC:
         case CLOCK_EVT_MODE_ONESHOT:
-                __setup_APIC_LVTT(calibration_result,
+                __setup_APIC_LVTT(lapic_timer_frequency,
                                   mode != CLOCK_EVT_MODE_PERIODIC, 1);
                 break;
         case CLOCK_EVT_MODE_UNUSED:
@@ -638,6 +638,25 @@ static int __init calibrate_APIC_clock(void)
         long delta, deltatsc;
         int pm_referenced = 0;
 
+        /**
+         * check if lapic timer has already been calibrated by platform
+         * specific routine, such as tsc calibration code. if so, we just fill
+         * in the clockevent structure and return.
+         */
+
+        if (lapic_timer_frequency) {
+                apic_printk(APIC_VERBOSE, "lapic timer already calibrated %d\n",
+                                lapic_timer_frequency);
+                lapic_clockevent.mult = div_sc(lapic_timer_frequency/APIC_DIVISOR,
+                                        TICK_NSEC, lapic_clockevent.shift);
+                lapic_clockevent.max_delta_ns =
+                        clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
+                lapic_clockevent.min_delta_ns =
+                        clockevent_delta2ns(0xF, &lapic_clockevent);
+                lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
+                return 0;
+        }
+
         local_irq_disable();
 
         /* Replace the global interrupt handler */
@@ -679,12 +698,12 @@ static int __init calibrate_APIC_clock(void)
         lapic_clockevent.min_delta_ns =
                 clockevent_delta2ns(0xF, &lapic_clockevent);
 
-        calibration_result = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
+        lapic_timer_frequency = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
 
         apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
         apic_printk(APIC_VERBOSE, "..... mult: %u\n", lapic_clockevent.mult);
         apic_printk(APIC_VERBOSE, "..... calibration result: %u\n",
-                    calibration_result);
+                    lapic_timer_frequency);
 
         if (cpu_has_tsc) {
                 apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
@@ -695,13 +714,13 @@ static int __init calibrate_APIC_clock(void)
 
         apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
                     "%u.%04u MHz.\n",
-                    calibration_result / (1000000 / HZ),
-                    calibration_result % (1000000 / HZ));
+                    lapic_timer_frequency / (1000000 / HZ),
+                    lapic_timer_frequency % (1000000 / HZ));
 
         /*
          * Do a sanity check on the APIC calibration result
          */
-        if (calibration_result < (1000000 / HZ)) {
+        if (lapic_timer_frequency < (1000000 / HZ)) {
                 local_irq_enable();
                 pr_warning("APIC frequency too slow, disabling apic timer\n");
                 return -1;
@@ -1437,27 +1456,21 @@ void enable_x2apic(void)
 
 int __init enable_IR(void)
 {
-#ifdef CONFIG_INTR_REMAP
+#ifdef CONFIG_IRQ_REMAP
         if (!intr_remapping_supported()) {
                 pr_debug("intr-remapping not supported\n");
-                return 0;
+                return -1;
         }
 
         if (!x2apic_preenabled && skip_ioapic_setup) {
                 pr_info("Skipped enabling intr-remap because of skipping "
                         "io-apic setup\n");
-                return 0;
+                return -1;
         }
 
-        if (enable_intr_remapping(x2apic_supported()))
-                return 0;
-
-        pr_info("Enabled Interrupt-remapping\n");
-
-        return 1;
-
+        return enable_intr_remapping();
 #endif
-        return 0;
+        return -1;
 }
 
 void __init enable_IR_x2apic(void)
@@ -1481,11 +1494,11 @@ void __init enable_IR_x2apic(void)
         mask_ioapic_entries();
 
         if (dmar_table_init_ret)
-                ret = 0;
+                ret = -1;
         else
                 ret = enable_IR();
 
-        if (!ret) {
+        if (ret < 0) {
                 /* IR is required if there is APIC ID > 255 even when running
                  * under KVM
                  */
@@ -1499,6 +1512,9 @@ void __init enable_IR_x2apic(void)
                 x2apic_force_phys();
         }
 
+        if (ret == IRQ_REMAP_XAPIC_MODE)
+                goto nox2apic;
+
         x2apic_enabled = 1;
 
         if (x2apic_supported() && !x2apic_mode) {
@@ -1508,19 +1524,21 @@ void __init enable_IR_x2apic(void)
         }
 
 nox2apic:
-        if (!ret) /* IR enabling failed */
+        if (ret < 0) /* IR enabling failed */
                 restore_ioapic_entries();
         legacy_pic->restore_mask();
         local_irq_restore(flags);
 
 out:
-        if (x2apic_enabled)
+        if (x2apic_enabled || !x2apic_supported())
                 return;
 
         if (x2apic_preenabled)
                 panic("x2apic: enabled by BIOS but kernel init failed.");
-        else if (cpu_has_x2apic)
-                pr_info("Not enabling x2apic, Intr-remapping init failed.\n");
+        else if (ret == IRQ_REMAP_XAPIC_MODE)
+                pr_info("x2apic not enabled, IRQ remapping is in xapic mode\n");
+        else if (ret < 0)
+                pr_info("x2apic not enabled, IRQ remapping init failed\n");
 }
 
 #ifdef CONFIG_X86_64