Merge branch 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 irq fixes from Ingo Molnar:
 "Two changes: a cpu-hotplug/irq race fix, plus a HyperV related fix"

* 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/irq: Fix fixup_irqs() error handling
  x86, irq, pic: Probe for legacy PIC and set legacy_pic appropriately

4 files changed, 46 insertions, 24 deletions

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 9d0a9795a0f8..81e08eff05ee 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2297,7 +2297,7 @@ int __ioapic_set_affinity(struct irq_data *data, const struct cpumask *mask,
         int err;
 
         if (!config_enabled(CONFIG_SMP))
-                return -1;
+                return -EPERM;
 
         if (!cpumask_intersects(mask, cpu_online_mask))
                 return -EINVAL;
@@ -2328,7 +2328,7 @@ int native_ioapic_set_affinity(struct irq_data *data,
         int ret;
 
         if (!config_enabled(CONFIG_SMP))
-                return -1;
+                return -EPERM;
 
         raw_spin_lock_irqsave(&ioapic_lock, flags);
         ret = __ioapic_set_affinity(data, mask, &dest);
@@ -3001,9 +3001,11 @@ msi_set_affinity(struct irq_data *data, const struct cpumask *mask, bool force)
         struct irq_cfg *cfg = data->chip_data;
         struct msi_msg msg;
         unsigned int dest;
+        int ret;
 
-        if (__ioapic_set_affinity(data, mask, &dest))
-                return -1;
+        ret = __ioapic_set_affinity(data, mask, &dest);
+        if (ret)
+                return ret;
 
         __get_cached_msi_msg(data->msi_desc, &msg);
 
@@ -3100,9 +3102,11 @@ dmar_msi_set_affinity(struct irq_data *data, const struct cpumask *mask,
         struct irq_cfg *cfg = data->chip_data;
         unsigned int dest, irq = data->irq;
         struct msi_msg msg;
+        int ret;
 
-        if (__ioapic_set_affinity(data, mask, &dest))
-                return -1;
+        ret = __ioapic_set_affinity(data, mask, &dest);
+        if (ret)
+                return ret;
 
         dmar_msi_read(irq, &msg);
 
@@ -3149,9 +3153,11 @@ static int hpet_msi_set_affinity(struct irq_data *data,
         struct irq_cfg *cfg = data->chip_data;
         struct msi_msg msg;
         unsigned int dest;
+        int ret;
 
-        if (__ioapic_set_affinity(data, mask, &dest))
-                return -1;
+        ret = __ioapic_set_affinity(data, mask, &dest);
+        if (ret)
+                return ret;
 
         hpet_msi_read(data->handler_data, &msg);
 
@@ -3218,9 +3224,11 @@ ht_set_affinity(struct irq_data *data, const struct cpumask *mask, bool force)
 {
         struct irq_cfg *cfg = data->chip_data;
         unsigned int dest;
+        int ret;
 
-        if (__ioapic_set_affinity(data, mask, &dest))
-                return -1;
+        ret = __ioapic_set_affinity(data, mask, &dest);
+        if (ret)
+                return ret;
 
         target_ht_irq(data->irq, dest, cfg->vector);
         return IRQ_SET_MASK_OK_NOCOPY;
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 76f98fe5b35c..a450373e8e91 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -132,15 +132,6 @@ static void __init ms_hyperv_init_platform(void)
                 lapic_timer_frequency = hv_lapic_frequency;
                 printk(KERN_INFO "HyperV: LAPIC Timer Frequency: %#x\n",
                                 lapic_timer_frequency);
-
-                /*
-                 * On Hyper-V, when we are booting off an EFI firmware stack,
-                 * we do not have many legacy devices including PIC, PIT etc.
-                 */
-                if (efi_enabled(EFI_BOOT)) {
-                        printk(KERN_INFO "HyperV: Using null_legacy_pic\n");
-                        legacy_pic = &null_legacy_pic;
-                }
         }
 #endif
 
diff --git a/arch/x86/kernel/i8259.c b/arch/x86/kernel/i8259.c
index 2e977b5d61dd..8af817105e29 100644
--- a/arch/x86/kernel/i8259.c
+++ b/arch/x86/kernel/i8259.c
@@ -299,13 +299,31 @@ static void unmask_8259A(void)
 static void init_8259A(int auto_eoi)
 {
         unsigned long flags;
+        unsigned char probe_val = ~(1 << PIC_CASCADE_IR);
+        unsigned char new_val;
 
         i8259A_auto_eoi = auto_eoi;
 
         raw_spin_lock_irqsave(&i8259A_lock, flags);
 
-        outb(0xff, PIC_MASTER_IMR);     /* mask all of 8259A-1 */
+        /*
+         * Check to see if we have a PIC.
+         * Mask all except the cascade and read
+         * back the value we just wrote. If we don't
+         * have a PIC, we will read 0xff as opposed to the
+         * value we wrote.
+         */
         outb(0xff, PIC_SLAVE_IMR);      /* mask all of 8259A-2 */
+        outb(probe_val, PIC_MASTER_IMR);
+        new_val = inb(PIC_MASTER_IMR);
+        if (new_val != probe_val) {
+                printk(KERN_INFO "Using NULL legacy PIC\n");
+                legacy_pic = &null_legacy_pic;
+                raw_spin_unlock_irqrestore(&i8259A_lock, flags);
+                return;
+        }
+
+        outb(0xff, PIC_MASTER_IMR);     /* mask all of 8259A-1 */
 
         /*
          * outb_pic - this has to work on a wide range of PC hardware.
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 11ccfb0a63e7..922d28581024 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -365,6 +365,7 @@ void fixup_irqs(void)
         struct irq_desc *desc;
         struct irq_data *data;
         struct irq_chip *chip;
+        int ret;
 
         for_each_irq_desc(irq, desc) {
                 int break_affinity = 0;
@@ -403,10 +404,14 @@ void fixup_irqs(void)
                 if (!irqd_can_move_in_process_context(data) && chip->irq_mask)
                         chip->irq_mask(data);
 
-                if (chip->irq_set_affinity)
-                        chip->irq_set_affinity(data, affinity, true);
-                else if (!(warned++))
-                        set_affinity = 0;
+                if (chip->irq_set_affinity) {
+                        ret = chip->irq_set_affinity(data, affinity, true);
+                        if (ret == -ENOSPC)
+                                pr_crit("IRQ %d set affinity failed because there are no available vectors.  The device assigned to this IRQ is unstable.\n", irq);
+                } else {
+                        if (!(warned++))
+                                set_affinity = 0;
+                }
 
                 /*
                  * We unmask if the irq was not marked masked by the