Merge remote branch 'origin/x86/apic' into x86/mrst

Conflicts:
	arch/x86/kernel/apic/io_apic.c

26 files changed, 333 insertions, 230 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 736d45602886..51bceb0fb277 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1772,6 +1772,12 @@ and is between 256 and 4096 characters. It is defined in the file
                         purges which is reported from either PAL_VM_SUMMARY or
                         SAL PALO.
 
+        nr_cpus=        [SMP] Maximum number of processors that an SMP kernel
+                        could support.  nr_cpus=n : n >= 1 limits the kernel to
+                        supporting 'n' processors. Later in runtime you can not
+                        use hotplug cpu feature to put more cpu back to online.
+                        just like you compile the kernel NR_CPUS=n
+
         nr_uarts=       [SERIAL] maximum number of UARTs to be registered.
 
         numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
diff --git a/arch/ia64/include/asm/xen/events.h b/arch/ia64/include/asm/xen/events.h
index b8370c8b6198..baa74c82aa71 100644
--- a/arch/ia64/include/asm/xen/events.h
+++ b/arch/ia64/include/asm/xen/events.h
@@ -36,10 +36,6 @@ static inline int xen_irqs_disabled(struct pt_regs *regs)
         return !(ia64_psr(regs)->i);
 }
 
-static inline void handle_irq(int irq, struct pt_regs *regs)
-{
-        __do_IRQ(irq);
-}
 #define irq_ctx_init(cpu)       do { } while (0)
 
 #endif /* _ASM_IA64_XEN_EVENTS_H */
diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index 40574ae11401..605a08b29721 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -881,8 +881,8 @@ __init void prefill_possible_map(void)
 
         possible = available_cpus + additional_cpus;
 
-        if (possible > NR_CPUS)
-                possible = NR_CPUS;
+        if (possible > nr_cpu_ids)
+                possible = nr_cpu_ids;
 
         printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
                 possible, max((possible - available_cpus), 0));
diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c
index f9f472462753..14531abdd0ce 100644
--- a/arch/x86/ia32/ia32_aout.c
+++ b/arch/x86/ia32/ia32_aout.c
@@ -327,7 +327,6 @@ static int load_aout_binary(struct linux_binprm *bprm, struct pt_regs *regs)
         current->mm->free_area_cache = TASK_UNMAPPED_BASE;
         current->mm->cached_hole_size = 0;
 
-        current->mm->mmap = NULL;
         install_exec_creds(bprm);
         current->flags &= ~PF_FORKNOEXEC;
 
diff --git a/arch/x86/include/asm/i8259.h b/arch/x86/include/asm/i8259.h
index 2832babd91fc..1655147646aa 100644
--- a/arch/x86/include/asm/i8259.h
+++ b/arch/x86/include/asm/i8259.h
@@ -24,7 +24,7 @@ extern unsigned int cached_irq_mask;
 #define SLAVE_ICW4_DEFAULT      0x01
 #define PIC_ICW4_AEOI           2
 
-extern spinlock_t i8259A_lock;
+extern raw_spinlock_t i8259A_lock;
 
 /* the PIC may need a careful delay on some platforms, hence specific calls */
 static inline unsigned char inb_pic(unsigned int port)
diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
index 84fdd5110948..31dfb42d8649 100644
--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -158,6 +158,7 @@ extern int io_apic_get_redir_entries(int ioapic);
 struct io_apic_irq_attr;
 extern int io_apic_set_pci_routing(struct device *dev, int irq,
                  struct io_apic_irq_attr *irq_attr);
+void setup_IO_APIC_irq_extra(u32 gsi);
 extern int (*ioapic_renumber_irq)(int ioapic, int irq);
 extern void ioapic_init_mappings(void);
 extern void ioapic_insert_resources(void);
diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index 5458380b6ef8..262292729fc4 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -48,5 +48,6 @@ extern DECLARE_BITMAP(used_vectors, NR_VECTORS);
 extern int vector_used_by_percpu_irq(unsigned int vector);
 
 extern void init_ISA_irqs(void);
+extern int nr_legacy_irqs;
 
 #endif /* _ASM_X86_IRQ_H */
diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
index 4611f085cd43..8767d99c4f64 100644
--- a/arch/x86/include/asm/irq_vectors.h
+++ b/arch/x86/include/asm/irq_vectors.h
@@ -28,28 +28,33 @@
 #define MCE_VECTOR                      0x12
 
 /*
- * IDT vectors usable for external interrupt sources start
- * at 0x20:
+ * IDT vectors usable for external interrupt sources start at 0x20.
+ * (0x80 is the syscall vector, 0x30-0x3f are for ISA)
  */
 #define FIRST_EXTERNAL_VECTOR           0x20
-
-#ifdef CONFIG_X86_32
-# define SYSCALL_VECTOR                 0x80
-# define IA32_SYSCALL_VECTOR            0x80
-#else
-# define IA32_SYSCALL_VECTOR            0x80
-#endif
+/*
+ * We start allocating at 0x21 to spread out vectors evenly between
+ * priority levels. (0x80 is the syscall vector)
+ */
+#define VECTOR_OFFSET_START             1
 
 /*
- * Reserve the lowest usable priority level 0x20 - 0x2f for triggering
- * cleanup after irq migration.
+ * Reserve the lowest usable vector (and hence lowest priority)  0x20 for
+ * triggering cleanup after irq migration. 0x21-0x2f will still be used
+ * for device interrupts.
  */
 #define IRQ_MOVE_CLEANUP_VECTOR         FIRST_EXTERNAL_VECTOR
 
+#define IA32_SYSCALL_VECTOR             0x80
+#ifdef CONFIG_X86_32
+# define SYSCALL_VECTOR                 0x80
+#endif
+
 /*
  * Vectors 0x30-0x3f are used for ISA interrupts.
+ *   round up to the next 16-vector boundary
  */
-#define IRQ0_VECTOR                     (FIRST_EXTERNAL_VECTOR + 0x10)
+#define IRQ0_VECTOR                     ((FIRST_EXTERNAL_VECTOR + 16) & ~15)
 
 #define IRQ1_VECTOR                     (IRQ0_VECTOR +  1)
 #define IRQ2_VECTOR                     (IRQ0_VECTOR +  2)
@@ -120,13 +125,6 @@
  */
 #define MCE_SELF_VECTOR                 0xeb
 
-/*
- * First APIC vector available to drivers: (vectors 0x30-0xee) we
- * start at 0x31(0x41) to spread out vectors evenly between priority
- * levels. (0x80 is the syscall vector)
- */
-#define FIRST_DEVICE_VECTOR             (IRQ15_VECTOR + 2)
-
 #define NR_VECTORS                       256
 
 #define FPU_IRQ                           13
@@ -154,21 +152,21 @@ static inline int invalid_vm86_irq(int irq)
 
 #define NR_IRQS_LEGACY                    16
 
-#define CPU_VECTOR_LIMIT                (  8 * NR_CPUS      )
 #define IO_APIC_VECTOR_LIMIT            ( 32 * MAX_IO_APICS )
 
 #ifdef CONFIG_X86_IO_APIC
 # ifdef CONFIG_SPARSE_IRQ
+#  define CPU_VECTOR_LIMIT              (64 * NR_CPUS)
 #  define NR_IRQS                                       \
         (CPU_VECTOR_LIMIT > IO_APIC_VECTOR_LIMIT ?      \
                 (NR_VECTORS + CPU_VECTOR_LIMIT)  :      \
                 (NR_VECTORS + IO_APIC_VECTOR_LIMIT))
 # else
-#  if NR_CPUS < MAX_IO_APICS
-#   define NR_IRQS                      (NR_VECTORS + 4*CPU_VECTOR_LIMIT)
-#  else
-#   define NR_IRQS                      (NR_VECTORS + IO_APIC_VECTOR_LIMIT)
-#  endif
+#  define CPU_VECTOR_LIMIT              (32 * NR_CPUS)
+#  define NR_IRQS                                       \
+        (CPU_VECTOR_LIMIT < IO_APIC_VECTOR_LIMIT ?      \
+                (NR_VECTORS + CPU_VECTOR_LIMIT)  :      \
+                (NR_VECTORS + IO_APIC_VECTOR_LIMIT))
 # endif
 #else /* !CONFIG_X86_IO_APIC: */
 # define NR_IRQS                        NR_IRQS_LEGACY
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 054a5f5548b0..db2773c6defd 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -447,6 +447,12 @@ void __init acpi_pic_sci_set_trigger(unsigned int irq, u16 trigger)
 int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
 {
         *irq = gsi;
+
+#ifdef CONFIG_X86_IO_APIC
+        if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
+                setup_IO_APIC_irq_extra(gsi);
+#endif
+
         return 0;
 }
 
@@ -474,7 +480,8 @@ int acpi_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity)
                 plat_gsi = mp_register_gsi(dev, gsi, trigger, polarity);
         }
 #endif
-        acpi_gsi_to_irq(plat_gsi, &irq);
+        irq = plat_gsi;
+
         return irq;
 }
 
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 3592a72f3f0a..b34854358ee6 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -73,8 +73,8 @@
  */
 int sis_apic_bug = -1;
 
-static DEFINE_SPINLOCK(ioapic_lock);
-static DEFINE_SPINLOCK(vector_lock);
+static DEFINE_RAW_SPINLOCK(ioapic_lock);
+static DEFINE_RAW_SPINLOCK(vector_lock);
 
 /*
  * # of IRQ routing registers
@@ -167,8 +167,14 @@ int __init arch_early_irq_init(void)
                 desc->chip_data = &cfg[i];
                 zalloc_cpumask_var_node(&cfg[i].domain, GFP_NOWAIT, node);
                 zalloc_cpumask_var_node(&cfg[i].old_domain, GFP_NOWAIT, node);
-                if (i < legacy_pic->nr_legacy_irqs)
-                        cpumask_setall(cfg[i].domain);
+                /*
+                 * For legacy IRQ's, start with assigning irq0 to irq15 to
+                 * IRQ0_VECTOR to IRQ15_VECTOR on cpu 0.
+                 */
+                if (i < legacy_pic->nr_legacy_irqs) {
+                        cfg[i].vector = IRQ0_VECTOR + i;
+                        cpumask_set_cpu(0, cfg[i].domain);
+                }
         }
 
         return 0;
@@ -388,7 +394,7 @@ static bool io_apic_level_ack_pending(struct irq_cfg *cfg)
         struct irq_pin_list *entry;
         unsigned long flags;
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         for_each_irq_pin(entry, cfg->irq_2_pin) {
                 unsigned int reg;
                 int pin;
@@ -397,11 +403,11 @@ static bool io_apic_level_ack_pending(struct irq_cfg *cfg)
                 reg = io_apic_read(entry->apic, 0x10 + pin*2);
                 /* Is the remote IRR bit set? */
                 if (reg & IO_APIC_REDIR_REMOTE_IRR) {
-                        spin_unlock_irqrestore(&ioapic_lock, flags);
+                        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
                         return true;
                 }
         }
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
         return false;
 }
@@ -415,10 +421,10 @@ static struct IO_APIC_route_entry ioapic_read_entry(int apic, int pin)
 {
         union entry_union eu;
         unsigned long flags;
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         eu.w1 = io_apic_read(apic, 0x10 + 2 * pin);
         eu.w2 = io_apic_read(apic, 0x11 + 2 * pin);
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
         return eu.entry;
 }
 
@@ -441,9 +447,9 @@ __ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
 void ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
 {
         unsigned long flags;
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         __ioapic_write_entry(apic, pin, e);
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
 /*
@@ -456,10 +462,10 @@ static void ioapic_mask_entry(int apic, int pin)
         unsigned long flags;
         union entry_union eu = { .entry.mask = 1 };
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         io_apic_write(apic, 0x10 + 2*pin, eu.w1);
         io_apic_write(apic, 0x11 + 2*pin, eu.w2);
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
 /*
@@ -586,9 +592,9 @@ static void mask_IO_APIC_irq_desc(struct irq_desc *desc)
 
         BUG_ON(!cfg);
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         __mask_IO_APIC_irq(cfg);
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
 static void unmask_IO_APIC_irq_desc(struct irq_desc *desc)
@@ -596,9 +602,9 @@ static void unmask_IO_APIC_irq_desc(struct irq_desc *desc)
         struct irq_cfg *cfg = desc->chip_data;
         unsigned long flags;
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         __unmask_IO_APIC_irq(cfg);
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
 static void mask_IO_APIC_irq(unsigned int irq)
@@ -1122,12 +1128,12 @@ void lock_vector_lock(void)
         /* Used to the online set of cpus does not change
          * during assign_irq_vector.
          */
-        spin_lock(&vector_lock);
+        raw_spin_lock(&vector_lock);
 }
 
 void unlock_vector_lock(void)
 {
-        spin_unlock(&vector_lock);
+        raw_spin_unlock(&vector_lock);
 }
 
 static int
@@ -1144,7 +1150,8 @@ __assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask)
          * Also, we've got to be careful not to trash gate
          * 0x80, because int 0x80 is hm, kind of importantish. ;)
          */
-        static int current_vector = FIRST_DEVICE_VECTOR, current_offset = 0;
+        static int current_vector = FIRST_EXTERNAL_VECTOR + VECTOR_OFFSET_START;
+        static int current_offset = VECTOR_OFFSET_START % 8;
         unsigned int old_vector;
         int cpu, err;
         cpumask_var_t tmp_mask;
@@ -1180,7 +1187,7 @@ next:
                 if (vector >= first_system_vector) {
                         /* If out of vectors on large boxen, must share them. */
                         offset = (offset + 1) % 8;
-                        vector = FIRST_DEVICE_VECTOR + offset;
+                        vector = FIRST_EXTERNAL_VECTOR + offset;
                 }
                 if (unlikely(current_vector == vector))
                         continue;
@@ -1214,9 +1221,9 @@ int assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask)
         int err;
         unsigned long flags;
 
-        spin_lock_irqsave(&vector_lock, flags);
+        raw_spin_lock_irqsave(&vector_lock, flags);
         err = __assign_irq_vector(irq, cfg, mask);
-        spin_unlock_irqrestore(&vector_lock, flags);
+        raw_spin_unlock_irqrestore(&vector_lock, flags);
         return err;
 }
 
@@ -1250,11 +1257,16 @@ static void __clear_irq_vector(int irq, struct irq_cfg *cfg)
 void __setup_vector_irq(int cpu)
 {
         /* Initialize vector_irq on a new cpu */
-        /* This function must be called with vector_lock held */
         int irq, vector;
         struct irq_cfg *cfg;
         struct irq_desc *desc;
 
+        /*
+         * vector_lock will make sure that we don't run into irq vector
+         * assignments that might be happening on another cpu in parallel,
+         * while we setup our initial vector to irq mappings.
+         */
+        raw_spin_lock(&vector_lock);
         /* Mark the inuse vectors */
         for_each_irq_desc(irq, desc) {
                 cfg = desc->chip_data;
@@ -1273,6 +1285,7 @@ void __setup_vector_irq(int cpu)
                 if (!cpumask_test_cpu(cpu, cfg->domain))
                         per_cpu(vector_irq, cpu)[vector] = -1;
         }
+        raw_spin_unlock(&vector_lock);
 }
 
 static struct irq_chip ioapic_chip;
@@ -1422,6 +1435,14 @@ static void setup_IO_APIC_irq(int apic_id, int pin, unsigned int irq, struct irq
 
         cfg = desc->chip_data;
 
+        /*
+         * For legacy irqs, cfg->domain starts with cpu 0 for legacy
+         * controllers like 8259. Now that IO-APIC can handle this irq, update
+         * the cfg->domain.
+         */
+        if (irq < nr_legacy_irqs && cpumask_test_cpu(0, cfg->domain))
+                apic->vector_allocation_domain(0, cfg->domain);
+
         if (assign_irq_vector(irq, cfg, apic->target_cpus()))
                 return;
 
@@ -1521,6 +1542,56 @@ static void __init setup_IO_APIC_irqs(void)
 }
 
 /*
+ * for the gsit that is not in first ioapic
+ * but could not use acpi_register_gsi()
+ * like some special sci in IBM x3330
+ */
+void setup_IO_APIC_irq_extra(u32 gsi)
+{
+        int apic_id = 0, pin, idx, irq;
+        int node = cpu_to_node(boot_cpu_id);
+        struct irq_desc *desc;
+        struct irq_cfg *cfg;
+
+        /*
+         * Convert 'gsi' to 'ioapic.pin'.
+         */
+        apic_id = mp_find_ioapic(gsi);
+        if (apic_id < 0)
+                return;
+
+        pin = mp_find_ioapic_pin(apic_id, gsi);
+        idx = find_irq_entry(apic_id, pin, mp_INT);
+        if (idx == -1)
+                return;
+
+        irq = pin_2_irq(idx, apic_id, pin);
+#ifdef CONFIG_SPARSE_IRQ
+        desc = irq_to_desc(irq);
+        if (desc)
+                return;
+#endif
+        desc = irq_to_desc_alloc_node(irq, node);
+        if (!desc) {
+                printk(KERN_INFO "can not get irq_desc for %d\n", irq);
+                return;
+        }
+
+        cfg = desc->chip_data;
+        add_pin_to_irq_node(cfg, node, apic_id, pin);
+
+        if (test_bit(pin, mp_ioapic_routing[apic_id].pin_programmed)) {
+                pr_debug("Pin %d-%d already programmed\n",
+                         mp_ioapics[apic_id].apicid, pin);
+                return;
+        }
+        set_bit(pin, mp_ioapic_routing[apic_id].pin_programmed);
+
+        setup_IO_APIC_irq(apic_id, pin, irq, desc,
+                        irq_trigger(idx), irq_polarity(idx));
+}
+
+/*
  * Set up the timer pin, possibly with the 8259A-master behind.
  */
 static void __init setup_timer_IRQ0_pin(unsigned int apic_id, unsigned int pin,
@@ -1583,14 +1654,14 @@ __apicdebuginit(void) print_IO_APIC(void)
 
         for (apic = 0; apic < nr_ioapics; apic++) {
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         reg_00.raw = io_apic_read(apic, 0);
         reg_01.raw = io_apic_read(apic, 1);
         if (reg_01.bits.version >= 0x10)
                 reg_02.raw = io_apic_read(apic, 2);
         if (reg_01.bits.version >= 0x20)
                 reg_03.raw = io_apic_read(apic, 3);
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
         printk("\n");
         printk(KERN_DEBUG "IO APIC #%d......\n", mp_ioapics[apic].apicid);
@@ -1812,7 +1883,7 @@ __apicdebuginit(void) print_PIC(void)
 
         printk(KERN_DEBUG "\nprinting PIC contents\n");
 
-        spin_lock_irqsave(&i8259A_lock, flags);
+        raw_spin_lock_irqsave(&i8259A_lock, flags);
 
         v = inb(0xa1) << 8 | inb(0x21);
         printk(KERN_DEBUG "... PIC  IMR: %04x\n", v);
@@ -1826,7 +1897,7 @@ __apicdebuginit(void) print_PIC(void)
         outb(0x0a,0xa0);
         outb(0x0a,0x20);
 
-        spin_unlock_irqrestore(&i8259A_lock, flags);
+        raw_spin_unlock_irqrestore(&i8259A_lock, flags);
 
         printk(KERN_DEBUG "... PIC  ISR: %04x\n", v);
 
@@ -1885,9 +1956,9 @@ void __init enable_IO_APIC(void)
          * The number of IO-APIC IRQ registers (== #pins):
          */
         for (apic = 0; apic < nr_ioapics; apic++) {
-                spin_lock_irqsave(&ioapic_lock, flags);
+                raw_spin_lock_irqsave(&ioapic_lock, flags);
                 reg_01.raw = io_apic_read(apic, 1);
-                spin_unlock_irqrestore(&ioapic_lock, flags);
+                raw_spin_unlock_irqrestore(&ioapic_lock, flags);
                 nr_ioapic_registers[apic] = reg_01.bits.entries+1;
         }
 
@@ -2027,9 +2098,9 @@ void __init setup_ioapic_ids_from_mpc(void)
         for (apic_id = 0; apic_id < nr_ioapics; apic_id++) {
 
                 /* Read the register 0 value */
-                spin_lock_irqsave(&ioapic_lock, flags);
+                raw_spin_lock_irqsave(&ioapic_lock, flags);
                 reg_00.raw = io_apic_read(apic_id, 0);
-                spin_unlock_irqrestore(&ioapic_lock, flags);
+                raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
                 old_id = mp_ioapics[apic_id].apicid;
 
@@ -2088,16 +2159,16 @@ void __init setup_ioapic_ids_from_mpc(void)
                         mp_ioapics[apic_id].apicid);
 
                 reg_00.bits.ID = mp_ioapics[apic_id].apicid;
-                spin_lock_irqsave(&ioapic_lock, flags);
+                raw_spin_lock_irqsave(&ioapic_lock, flags);
                 io_apic_write(apic_id, 0, reg_00.raw);
-                spin_unlock_irqrestore(&ioapic_lock, flags);
+                raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
                 /*
                  * Sanity check
                  */
-                spin_lock_irqsave(&ioapic_lock, flags);
+                raw_spin_lock_irqsave(&ioapic_lock, flags);
                 reg_00.raw = io_apic_read(apic_id, 0);
-                spin_unlock_irqrestore(&ioapic_lock, flags);
+                raw_spin_unlock_irqrestore(&ioapic_lock, flags);
                 if (reg_00.bits.ID != mp_ioapics[apic_id].apicid)
                         printk("could not set ID!\n");
                 else
@@ -2180,7 +2251,7 @@ static unsigned int startup_ioapic_irq(unsigned int irq)
         unsigned long flags;
         struct irq_cfg *cfg;
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         if (irq < legacy_pic->nr_legacy_irqs) {
                 legacy_pic->chip->mask(irq);
                 if (legacy_pic->irq_pending(irq))
@@ -2188,7 +2259,7 @@ static unsigned int startup_ioapic_irq(unsigned int irq)
         }
         cfg = irq_cfg(irq);
         __unmask_IO_APIC_irq(cfg);
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
         return was_pending;
 }
@@ -2199,9 +2270,9 @@ static int ioapic_retrigger_irq(unsigned int irq)
         struct irq_cfg *cfg = irq_cfg(irq);
         unsigned long flags;
 
-        spin_lock_irqsave(&vector_lock, flags);
+        raw_spin_lock_irqsave(&vector_lock, flags);
         apic->send_IPI_mask(cpumask_of(cpumask_first(cfg->domain)), cfg->vector);
-        spin_unlock_irqrestore(&vector_lock, flags);
+        raw_spin_unlock_irqrestore(&vector_lock, flags);
 
         return 1;
 }
@@ -2294,14 +2365,14 @@ set_ioapic_affinity_irq_desc(struct irq_desc *desc, const struct cpumask *mask)
         irq = desc->irq;
         cfg = desc->chip_data;
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         ret = set_desc_affinity(desc, mask, &dest);
         if (!ret) {
                 /* Only the high 8 bits are valid. */
                 dest = SET_APIC_LOGICAL_ID(dest);
                 __target_IO_APIC_irq(irq, dest, cfg);
         }
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
         return ret;
 }
@@ -2536,9 +2607,9 @@ static void eoi_ioapic_irq(struct irq_desc *desc)
         irq = desc->irq;
         cfg = desc->chip_data;
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         __eoi_ioapic_irq(irq, cfg);
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
 static void ack_apic_level(unsigned int irq)
@@ -3120,13 +3191,13 @@ static int ioapic_resume(struct sys_device *dev)
         data = container_of(dev, struct sysfs_ioapic_data, dev);
         entry = data->entry;
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         reg_00.raw = io_apic_read(dev->id, 0);
         if (reg_00.bits.ID != mp_ioapics[dev->id].apicid) {
                 reg_00.bits.ID = mp_ioapics[dev->id].apicid;
                 io_apic_write(dev->id, 0, reg_00.raw);
         }
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
         for (i = 0; i < nr_ioapic_registers[dev->id]; i++)
                 ioapic_write_entry(dev->id, i, entry[i]);
 
@@ -3189,7 +3260,7 @@ unsigned int create_irq_nr(unsigned int irq_want, int node)
         if (irq_want < nr_irqs_gsi)
                 irq_want = nr_irqs_gsi;
 
-        spin_lock_irqsave(&vector_lock, flags);
+        raw_spin_lock_irqsave(&vector_lock, flags);
         for (new = irq_want; new < nr_irqs; new++) {
                 desc_new = irq_to_desc_alloc_node(new, node);
                 if (!desc_new) {
@@ -3208,14 +3279,11 @@ unsigned int create_irq_nr(unsigned int irq_want, int node)
                         irq = new;
                 break;
         }
-        spin_unlock_irqrestore(&vector_lock, flags);
+        raw_spin_unlock_irqrestore(&vector_lock, flags);
+
+        if (irq > 0)
+                dynamic_irq_init_keep_chip_data(irq);
 
-        if (irq > 0) {
-                dynamic_irq_init(irq);
-                /* restore it, in case dynamic_irq_init clear it */
-                if (desc_new)
-                        desc_new->chip_data = cfg_new;
-        }
         return irq;
 }
 
@@ -3237,20 +3305,13 @@ int create_irq(void)
 void destroy_irq(unsigned int irq)
 {
         unsigned long flags;
-        struct irq_cfg *cfg;
-        struct irq_desc *desc;
 
-        /* store it, in case dynamic_irq_cleanup clear it */
-        desc = irq_to_desc(irq);
-        cfg = desc->chip_data;
-        dynamic_irq_cleanup(irq);
-        /* connect back irq_cfg */
-        desc->chip_data = cfg;
+        dynamic_irq_cleanup_keep_chip_data(irq);
 
         free_irte(irq);
-        spin_lock_irqsave(&vector_lock, flags);
-        __clear_irq_vector(irq, cfg);
-        spin_unlock_irqrestore(&vector_lock, flags);
+        raw_spin_lock_irqsave(&vector_lock, flags);
+        __clear_irq_vector(irq, get_irq_chip_data(irq));
+        raw_spin_unlock_irqrestore(&vector_lock, flags);
 }
 
 /*
@@ -3787,9 +3848,9 @@ int __init io_apic_get_redir_entries (int ioapic)
         union IO_APIC_reg_01    reg_01;
         unsigned long flags;
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         reg_01.raw = io_apic_read(ioapic, 1);
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
         return reg_01.bits.entries;
 }
@@ -3816,28 +3877,6 @@ void __init probe_nr_irqs_gsi(void)
         printk(KERN_DEBUG "nr_irqs_gsi: %d\n", nr_irqs_gsi);
 }
 
-#ifdef CONFIG_SPARSE_IRQ
-int __init arch_probe_nr_irqs(void)
-{
-        int nr;
-
-        if (nr_irqs > (NR_VECTORS * nr_cpu_ids))
-                nr_irqs = NR_VECTORS * nr_cpu_ids;
-
-        nr = nr_irqs_gsi + 8 * nr_cpu_ids;
-#if defined(CONFIG_PCI_MSI) || defined(CONFIG_HT_IRQ)
-        /*
-         * for MSI and HT dyn irq
-         */
-        nr += nr_irqs_gsi * 16;
-#endif
-        if (nr < nr_irqs)
-                nr_irqs = nr;
-
-        return 0;
-}
-#endif
-
 static int __io_apic_set_pci_routing(struct device *dev, int irq,
                                 struct io_apic_irq_attr *irq_attr)
 {
@@ -3951,9 +3990,9 @@ int __init io_apic_get_unique_id(int ioapic, int apic_id)
         if (physids_empty(apic_id_map))
                 apic->ioapic_phys_id_map(&phys_cpu_present_map, &apic_id_map);
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         reg_00.raw = io_apic_read(ioapic, 0);
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
         if (apic_id >= get_physical_broadcast()) {
                 printk(KERN_WARNING "IOAPIC[%d]: Invalid apic_id %d, trying "
@@ -3987,10 +4026,10 @@ int __init io_apic_get_unique_id(int ioapic, int apic_id)
         if (reg_00.bits.ID != apic_id) {
                 reg_00.bits.ID = apic_id;
 
-                spin_lock_irqsave(&ioapic_lock, flags);
+                raw_spin_lock_irqsave(&ioapic_lock, flags);
                 io_apic_write(ioapic, 0, reg_00.raw);
                 reg_00.raw = io_apic_read(ioapic, 0);
-                spin_unlock_irqrestore(&ioapic_lock, flags);
+                raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
                 /* Sanity check */
                 if (reg_00.bits.ID != apic_id) {
@@ -4011,9 +4050,9 @@ int __init io_apic_get_version(int ioapic)
         union IO_APIC_reg_01    reg_01;
         unsigned long flags;
 
-        spin_lock_irqsave(&ioapic_lock, flags);
+        raw_spin_lock_irqsave(&ioapic_lock, flags);
         reg_01.raw = io_apic_read(ioapic, 1);
-        spin_unlock_irqrestore(&ioapic_lock, flags);
+        raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
         return reg_01.bits.version;
 }
diff --git a/arch/x86/kernel/apic/nmi.c b/arch/x86/kernel/apic/nmi.c
index 3817739acee9..f72b5f0f388e 100644
--- a/arch/x86/kernel/apic/nmi.c
+++ b/arch/x86/kernel/apic/nmi.c
@@ -416,13 +416,13 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
 
         /* We can be called before check_nmi_watchdog, hence NULL check. */
         if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
-                static DEFINE_SPINLOCK(lock);   /* Serialise the printks */
+                static DEFINE_RAW_SPINLOCK(lock); /* Serialise the printks */
 
-                spin_lock(&lock);
+                raw_spin_lock(&lock);
                 printk(KERN_WARNING "NMI backtrace for cpu %d\n", cpu);
                 show_regs(regs);
                 dump_stack();
-                spin_unlock(&lock);
+                raw_spin_unlock(&lock);
                 cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
 
                 rc = 1;
diff --git a/arch/x86/kernel/i8259.c b/arch/x86/kernel/i8259.c
index 1c790e75f7a0..9bac6817456f 100644
--- a/arch/x86/kernel/i8259.c
+++ b/arch/x86/kernel/i8259.c
@@ -32,7 +32,7 @@
  */
 
 static int i8259A_auto_eoi;
-DEFINE_SPINLOCK(i8259A_lock);
+DEFINE_RAW_SPINLOCK(i8259A_lock);
 static void mask_and_ack_8259A(unsigned int);
 static void mask_8259A(void);
 static void unmask_8259A(void);
@@ -74,13 +74,13 @@ static void disable_8259A_irq(unsigned int irq)
         unsigned int mask = 1 << irq;
         unsigned long flags;
 
-        spin_lock_irqsave(&i8259A_lock, flags);
+        raw_spin_lock_irqsave(&i8259A_lock, flags);
         cached_irq_mask |= mask;
         if (irq & 8)
                 outb(cached_slave_mask, PIC_SLAVE_IMR);
         else
                 outb(cached_master_mask, PIC_MASTER_IMR);
-        spin_unlock_irqrestore(&i8259A_lock, flags);
+        raw_spin_unlock_irqrestore(&i8259A_lock, flags);
 }
 
 static void enable_8259A_irq(unsigned int irq)
@@ -88,13 +88,13 @@ static void enable_8259A_irq(unsigned int irq)
         unsigned int mask = ~(1 << irq);
         unsigned long flags;
 
-        spin_lock_irqsave(&i8259A_lock, flags);
+        raw_spin_lock_irqsave(&i8259A_lock, flags);
         cached_irq_mask &= mask;
         if (irq & 8)
                 outb(cached_slave_mask, PIC_SLAVE_IMR);
         else
                 outb(cached_master_mask, PIC_MASTER_IMR);
-        spin_unlock_irqrestore(&i8259A_lock, flags);
+        raw_spin_unlock_irqrestore(&i8259A_lock, flags);
 }
 
 static int i8259A_irq_pending(unsigned int irq)
@@ -103,12 +103,12 @@ static int i8259A_irq_pending(unsigned int irq)
         unsigned long flags;
         int ret;
 
-        spin_lock_irqsave(&i8259A_lock, flags);
+        raw_spin_lock_irqsave(&i8259A_lock, flags);
         if (irq < 8)
                 ret = inb(PIC_MASTER_CMD) & mask;
         else
                 ret = inb(PIC_SLAVE_CMD) & (mask >> 8);
-        spin_unlock_irqrestore(&i8259A_lock, flags);
+        raw_spin_unlock_irqrestore(&i8259A_lock, flags);
 
         return ret;
 }
@@ -156,7 +156,7 @@ static void mask_and_ack_8259A(unsigned int irq)
         unsigned int irqmask = 1 << irq;
         unsigned long flags;
 
-        spin_lock_irqsave(&i8259A_lock, flags);
+        raw_spin_lock_irqsave(&i8259A_lock, flags);
         /*
          * Lightweight spurious IRQ detection. We do not want
          * to overdo spurious IRQ handling - it's usually a sign
@@ -189,7 +189,7 @@ handle_real_irq:
                 outb(cached_master_mask, PIC_MASTER_IMR);
                 outb(0x60+irq, PIC_MASTER_CMD); /* 'Specific EOI to master */
         }
-        spin_unlock_irqrestore(&i8259A_lock, flags);
+        raw_spin_unlock_irqrestore(&i8259A_lock, flags);
         return;
 
 spurious_8259A_irq:
@@ -291,24 +291,24 @@ static void mask_8259A(void)
 {
         unsigned long flags;
 
-        spin_lock_irqsave(&i8259A_lock, flags);
+        raw_spin_lock_irqsave(&i8259A_lock, flags);
 
         outb(0xff, PIC_MASTER_IMR);     /* mask all of 8259A-1 */
         outb(0xff, PIC_SLAVE_IMR);      /* mask all of 8259A-2 */
 
-        spin_unlock_irqrestore(&i8259A_lock, flags);
+        raw_spin_unlock_irqrestore(&i8259A_lock, flags);
 }
 
 static void unmask_8259A(void)
 {
         unsigned long flags;
 
-        spin_lock_irqsave(&i8259A_lock, flags);
+        raw_spin_lock_irqsave(&i8259A_lock, flags);
 
         outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */
         outb(cached_slave_mask, PIC_SLAVE_IMR);   /* restore slave IRQ mask */
 
-        spin_unlock_irqrestore(&i8259A_lock, flags);
+        raw_spin_unlock_irqrestore(&i8259A_lock, flags);
 }
 
 static void init_8259A(int auto_eoi)
@@ -317,7 +317,7 @@ static void init_8259A(int auto_eoi)
 
         i8259A_auto_eoi = auto_eoi;
 
-        spin_lock_irqsave(&i8259A_lock, flags);
+        raw_spin_lock_irqsave(&i8259A_lock, flags);
 
         outb(0xff, PIC_MASTER_IMR);     /* mask all of 8259A-1 */
         outb(0xff, PIC_SLAVE_IMR);      /* mask all of 8259A-2 */
@@ -362,7 +362,7 @@ static void init_8259A(int auto_eoi)
         outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */
         outb(cached_slave_mask, PIC_SLAVE_IMR);   /* restore slave IRQ mask */
 
-        spin_unlock_irqrestore(&i8259A_lock, flags);
+        raw_spin_unlock_irqrestore(&i8259A_lock, flags);
 }
 
 /*
diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
index 89b9510e8030..d2f787b3de56 100644
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -84,24 +84,7 @@ static struct irqaction irq2 = {
 };
 
 DEFINE_PER_CPU(vector_irq_t, vector_irq) = {
-        [0 ... IRQ0_VECTOR - 1] = -1,
-        [IRQ0_VECTOR] = 0,
-        [IRQ1_VECTOR] = 1,
-        [IRQ2_VECTOR] = 2,
-        [IRQ3_VECTOR] = 3,
-        [IRQ4_VECTOR] = 4,
-        [IRQ5_VECTOR] = 5,
-        [IRQ6_VECTOR] = 6,
-        [IRQ7_VECTOR] = 7,
-        [IRQ8_VECTOR] = 8,
-        [IRQ9_VECTOR] = 9,
-        [IRQ10_VECTOR] = 10,
-        [IRQ11_VECTOR] = 11,
-        [IRQ12_VECTOR] = 12,
-        [IRQ13_VECTOR] = 13,
-        [IRQ14_VECTOR] = 14,
-        [IRQ15_VECTOR] = 15,
-        [IRQ15_VECTOR + 1 ... NR_VECTORS - 1] = -1
+        [0 ... NR_VECTORS - 1] = -1,
 };
 
 int vector_used_by_percpu_irq(unsigned int vector)
@@ -116,6 +99,9 @@ int vector_used_by_percpu_irq(unsigned int vector)
         return 0;
 }
 
+/* Number of legacy interrupts */
+int nr_legacy_irqs __read_mostly = NR_IRQS_LEGACY;
+
 void __init init_ISA_irqs(void)
 {
         int i;
@@ -142,6 +128,19 @@ void __init init_ISA_irqs(void)
 
 void __init init_IRQ(void)
 {
+        int i;
+
+        /*
+         * On cpu 0, Assign IRQ0_VECTOR..IRQ15_VECTOR's to IRQ 0..15.
+         * If these IRQ's are handled by legacy interrupt-controllers like PIC,
+         * then this configuration will likely be static after the boot. If
+         * these IRQ's are handled by more mordern controllers like IO-APIC,
+         * then this vector space can be freed and re-used dynamically as the
+         * irq's migrate etc.
+         */
+        for (i = 0; i < nr_legacy_irqs; i++)
+                per_cpu(vector_irq, 0)[IRQ0_VECTOR + i] = i;
+
         x86_init.irqs.intr_init();
 }
 
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 704bddcdf64d..8e1aac86b50c 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -461,6 +461,14 @@ static struct dmi_system_id __initdata pci_reboot_dmi_table[] = {
                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini3,1"),
                 },
         },
+        {       /* Handle problems with rebooting on the iMac9,1. */
+                .callback = set_pci_reboot,
+                .ident = "Apple iMac9,1",
+                .matches = {
+                        DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
+                        DMI_MATCH(DMI_PRODUCT_NAME, "iMac9,1"),
+                },
+        },
         { }
 };
 
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index f7a52f4a21a5..86f7edcd0438 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -243,6 +243,11 @@ static void __cpuinit smp_callin(void)
         map_cpu_to_logical_apicid();
 
         notify_cpu_starting(cpuid);
+
+        /*
+         * Need to setup vector mappings before we enable interrupts.
+         */
+        __setup_vector_irq(smp_processor_id());
         /*
          * Get our bogomips.
          *
@@ -317,7 +322,6 @@ notrace static void __cpuinit start_secondary(void *unused)
          */
         ipi_call_lock();
         lock_vector_lock();
-        __setup_vector_irq(smp_processor_id());
         set_cpu_online(smp_processor_id(), true);
         unlock_vector_lock();
         ipi_call_unlock();
@@ -1216,11 +1220,12 @@ __init void prefill_possible_map(void)
 
         total_cpus = max_t(int, possible, num_processors + disabled_cpus);
 
-        if (possible > CONFIG_NR_CPUS) {
+        /* nr_cpu_ids could be reduced via nr_cpus= */
+        if (possible > nr_cpu_ids) {
                 printk(KERN_WARNING
                         "%d Processors exceeds NR_CPUS limit of %d\n",
-                        possible, CONFIG_NR_CPUS);
-                possible = CONFIG_NR_CPUS;
+                        possible, nr_cpu_ids);
+                possible = nr_cpu_ids;
         }
 
         printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c
index be2573448ed9..fb5cc5e14cfa 100644
--- a/arch/x86/kernel/time.c
+++ b/arch/x86/kernel/time.c
@@ -70,11 +70,11 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
                  * manually to deassert NMI lines for the watchdog if run
                  * on an 82489DX-based system.
                  */
-                spin_lock(&i8259A_lock);
+                raw_spin_lock(&i8259A_lock);
                 outb(0x0c, PIC_MASTER_OCW3);
                 /* Ack the IRQ; AEOI will end it automatically. */
                 inb(PIC_MASTER_POLL);
-                spin_unlock(&i8259A_lock);
+                raw_spin_unlock(&i8259A_lock);
         }
 
         global_clock_event->event_handler(global_clock_event);
diff --git a/arch/x86/kernel/visws_quirks.c b/arch/x86/kernel/visws_quirks.c
index f067e9556a47..e680ea52db9b 100644
--- a/arch/x86/kernel/visws_quirks.c
+++ b/arch/x86/kernel/visws_quirks.c
@@ -553,7 +553,7 @@ static irqreturn_t piix4_master_intr(int irq, void *dev_id)
         struct irq_desc *desc;
         unsigned long flags;
 
-        spin_lock_irqsave(&i8259A_lock, flags);
+        raw_spin_lock_irqsave(&i8259A_lock, flags);
 
         /* Find out what's interrupting in the PIIX4 master 8259 */
         outb(0x0c, 0x20);               /* OCW3 Poll command */
@@ -590,7 +590,7 @@ static irqreturn_t piix4_master_intr(int irq, void *dev_id)
                 outb(0x60 + realirq, 0x20);
         }
 
-        spin_unlock_irqrestore(&i8259A_lock, flags);
+        raw_spin_unlock_irqrestore(&i8259A_lock, flags);
 
         desc = irq_to_desc(realirq);
 
@@ -608,7 +608,7 @@ static irqreturn_t piix4_master_intr(int irq, void *dev_id)
         return IRQ_HANDLED;
 
 out_unlock:
-        spin_unlock_irqrestore(&i8259A_lock, flags);
+        raw_spin_unlock_irqrestore(&i8259A_lock, flags);
         return IRQ_NONE;
 }
 
diff --git a/arch/x86/kernel/vmiclock_32.c b/arch/x86/kernel/vmiclock_32.c
index 74c92bb194df..2f1ca5614292 100644
--- a/arch/x86/kernel/vmiclock_32.c
+++ b/arch/x86/kernel/vmiclock_32.c
@@ -79,11 +79,7 @@ unsigned long vmi_tsc_khz(void)
 
 static inline unsigned int vmi_get_timer_vector(void)
 {
-#ifdef CONFIG_X86_IO_APIC
-        return FIRST_DEVICE_VECTOR;
-#else
-        return FIRST_EXTERNAL_VECTOR;
-#endif
+        return IRQ0_VECTOR;
 }
 
 /** vmi clockchip */
diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index 7ad48dfc12db..b8725461d887 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -279,9 +279,9 @@ int __init acpi_numa_init(void)
         /* SRAT: Static Resource Affinity Table */
         if (!acpi_table_parse(ACPI_SIG_SRAT, acpi_parse_srat)) {
                 acpi_table_parse_srat(ACPI_SRAT_TYPE_X2APIC_CPU_AFFINITY,
-                                      acpi_parse_x2apic_affinity, NR_CPUS);
+                                     acpi_parse_x2apic_affinity, nr_cpu_ids);
                 acpi_table_parse_srat(ACPI_SRAT_TYPE_CPU_AFFINITY,
-                                      acpi_parse_processor_affinity, NR_CPUS);
+                                     acpi_parse_processor_affinity, nr_cpu_ids);
                 ret = acpi_table_parse_srat(ACPI_SRAT_TYPE_MEMORY_AFFINITY,
                                             acpi_parse_memory_affinity,
                                             NR_NODE_MEMBLKS);
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index ce602dd09bc1..2f8413794d05 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -649,9 +649,13 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
                                 int bit_idx = __ffs(pending_bits);
                                 int port = (word_idx * BITS_PER_LONG) + bit_idx;
                                 int irq = evtchn_to_irq[port];
+                                struct irq_desc *desc;
 
-                                if (irq != -1)
-                                        handle_irq(irq, regs);
+                                if (irq != -1) {
+                                        desc = irq_to_desc(irq);
+                                        if (desc)
+                                                generic_handle_irq_desc(irq, desc);
+                                }
                         }
                 }
 
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 451481c082b5..4d9b26e044bc 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -400,7 +400,9 @@ static inline int irq_has_action(unsigned int irq)
 
 /* Dynamic irq helper functions */
 extern void dynamic_irq_init(unsigned int irq);
+void dynamic_irq_init_keep_chip_data(unsigned int irq);
 extern void dynamic_irq_cleanup(unsigned int irq);
+void dynamic_irq_cleanup_keep_chip_data(unsigned int irq);
 
 /* Set/get chip/data for an IRQ: */
 extern int set_irq_chip(unsigned int irq, struct irq_chip *chip);
diff --git a/init/main.c b/init/main.c
index 4cb47a159f02..05b5283e98fa 100644
--- a/init/main.c
+++ b/init/main.c
@@ -149,6 +149,20 @@ static int __init nosmp(char *str)
 
 early_param("nosmp", nosmp);
 
+/* this is hard limit */
+static int __init nrcpus(char *str)
+{
+        int nr_cpus;
+
+        get_option(&str, &nr_cpus);
+        if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
+                nr_cpu_ids = nr_cpus;
+
+        return 0;
+}
+
+early_param("nr_cpus", nrcpus);
+
 static int __init maxcpus(char *str)
 {
         get_option(&str, &setup_max_cpus);
@@ -584,6 +598,7 @@ asmlinkage void __init start_kernel(void)
                 local_irq_disable();
         }
         rcu_init();
+        radix_tree_init();
         /* init some links before init_ISA_irqs() */
         early_irq_init();
         init_IRQ();
@@ -657,7 +672,6 @@ asmlinkage void __init start_kernel(void)
         proc_caches_init();
         buffer_init();
         key_init();
-        radix_tree_init();
         security_init();
         vfs_caches_init(totalram_pages);
         signals_init();
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index ecc3fa28f666..d70394f12ee9 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -18,11 +18,7 @@
 
 #include "internals.h"
 
-/**
- *      dynamic_irq_init - initialize a dynamically allocated irq
- *      @irq:   irq number to initialize
- */
-void dynamic_irq_init(unsigned int irq)
+static void dynamic_irq_init_x(unsigned int irq, bool keep_chip_data)
 {
         struct irq_desc *desc;
         unsigned long flags;
@@ -41,7 +37,8 @@ void dynamic_irq_init(unsigned int irq)
         desc->depth = 1;
         desc->msi_desc = NULL;
         desc->handler_data = NULL;
-        desc->chip_data = NULL;
+        if (!keep_chip_data)
+                desc->chip_data = NULL;
         desc->action = NULL;
         desc->irq_count = 0;
         desc->irqs_unhandled = 0;
@@ -55,10 +52,26 @@ void dynamic_irq_init(unsigned int irq)
 }
 
 /**
- *      dynamic_irq_cleanup - cleanup a dynamically allocated irq
+ *      dynamic_irq_init - initialize a dynamically allocated irq
  *      @irq:   irq number to initialize
  */
-void dynamic_irq_cleanup(unsigned int irq)
+void dynamic_irq_init(unsigned int irq)
+{
+        dynamic_irq_init_x(irq, false);
+}
+
+/**
+ *      dynamic_irq_init_keep_chip_data - initialize a dynamically allocated irq
+ *      @irq:   irq number to initialize
+ *
+ *      does not set irq_to_desc(irq)->chip_data to NULL
+ */
+void dynamic_irq_init_keep_chip_data(unsigned int irq)
+{
+        dynamic_irq_init_x(irq, true);
+}
+
+static void dynamic_irq_cleanup_x(unsigned int irq, bool keep_chip_data)
 {
         struct irq_desc *desc = irq_to_desc(irq);
         unsigned long flags;
@@ -77,7 +90,8 @@ void dynamic_irq_cleanup(unsigned int irq)
         }
         desc->msi_desc = NULL;
         desc->handler_data = NULL;
-        desc->chip_data = NULL;
+        if (!keep_chip_data)
+                desc->chip_data = NULL;
         desc->handle_irq = handle_bad_irq;
         desc->chip = &no_irq_chip;
         desc->name = NULL;
@@ -85,6 +99,26 @@ void dynamic_irq_cleanup(unsigned int irq)
         raw_spin_unlock_irqrestore(&desc->lock, flags);
 }
 
+/**
+ *      dynamic_irq_cleanup - cleanup a dynamically allocated irq
+ *      @irq:   irq number to initialize
+ */
+void dynamic_irq_cleanup(unsigned int irq)
+{
+        dynamic_irq_cleanup_x(irq, false);
+}
+
+/**
+ *      dynamic_irq_cleanup_keep_chip_data - cleanup a dynamically allocated irq
+ *      @irq:   irq number to initialize
+ *
+ *      does not set irq_to_desc(irq)->chip_data to NULL
+ */
+void dynamic_irq_cleanup_keep_chip_data(unsigned int irq)
+{
+        dynamic_irq_cleanup_x(irq, true);
+}
+
 
 /**
  *      set_irq_chip - set the irq chip for an irq
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 814940e7f485..76d5a671bfe1 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -19,7 +19,7 @@
 #include <linux/kernel_stat.h>
 #include <linux/rculist.h>
 #include <linux/hash.h>
-#include <linux/bootmem.h>
+#include <linux/radix-tree.h>
 #include <trace/events/irq.h>
 
 #include "internals.h"
@@ -87,12 +87,8 @@ void __ref init_kstat_irqs(struct irq_desc *desc, int node, int nr)
 {
         void *ptr;
 
-        if (slab_is_available())
-                ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs),
-                                   GFP_ATOMIC, node);
-        else
-                ptr = alloc_bootmem_node(NODE_DATA(node),
-                                nr * sizeof(*desc->kstat_irqs));
+        ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs),
+                           GFP_ATOMIC, node);
 
         /*
          * don't overwite if can not get new one
@@ -132,7 +128,26 @@ static void init_one_irq_desc(int irq, struct irq_desc *desc, int node)
  */
 DEFINE_RAW_SPINLOCK(sparse_irq_lock);
 
-struct irq_desc **irq_desc_ptrs __read_mostly;
+static RADIX_TREE(irq_desc_tree, GFP_ATOMIC);
+
+static void set_irq_desc(unsigned int irq, struct irq_desc *desc)
+{
+        radix_tree_insert(&irq_desc_tree, irq, desc);
+}
+
+struct irq_desc *irq_to_desc(unsigned int irq)
+{
+        return radix_tree_lookup(&irq_desc_tree, irq);
+}
+
+void replace_irq_desc(unsigned int irq, struct irq_desc *desc)
+{
+        void **ptr;
+
+        ptr = radix_tree_lookup_slot(&irq_desc_tree, irq);
+        if (ptr)
+                radix_tree_replace_slot(ptr, desc);
+}
 
 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
         [0 ... NR_IRQS_LEGACY-1] = {
@@ -164,9 +179,6 @@ int __init early_irq_init(void)
         legacy_count = ARRAY_SIZE(irq_desc_legacy);
         node = first_online_node;
 
-        /* allocate irq_desc_ptrs array based on nr_irqs */
-        irq_desc_ptrs = kcalloc(nr_irqs, sizeof(void *), GFP_NOWAIT);
-
         /* allocate based on nr_cpu_ids */
         kstat_irqs_legacy = kzalloc_node(NR_IRQS_LEGACY * nr_cpu_ids *
                                           sizeof(int), GFP_NOWAIT, node);
@@ -180,23 +192,12 @@ int __init early_irq_init(void)
                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
                 alloc_desc_masks(&desc[i], node, true);
                 init_desc_masks(&desc[i]);
-                irq_desc_ptrs[i] = desc + i;
+                set_irq_desc(i, &desc[i]);
         }
 
-        for (i = legacy_count; i < nr_irqs; i++)
-                irq_desc_ptrs[i] = NULL;
-
         return arch_early_irq_init();
 }
 
-struct irq_desc *irq_to_desc(unsigned int irq)
-{
-        if (irq_desc_ptrs && irq < nr_irqs)
-                return irq_desc_ptrs[irq];
-
-        return NULL;
-}
-
 struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
 {
         struct irq_desc *desc;
@@ -208,21 +209,18 @@ struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
                 return NULL;
         }
 
-        desc = irq_desc_ptrs[irq];
+        desc = irq_to_desc(irq);
         if (desc)
                 return desc;
 
         raw_spin_lock_irqsave(&sparse_irq_lock, flags);
 
         /* We have to check it to avoid races with another CPU */
-        desc = irq_desc_ptrs[irq];
+        desc = irq_to_desc(irq);
         if (desc)
                 goto out_unlock;
 
-        if (slab_is_available())
-                desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
-        else
-                desc = alloc_bootmem_node(NODE_DATA(node), sizeof(*desc));
+        desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 
         printk(KERN_DEBUG "  alloc irq_desc for %d on node %d\n", irq, node);
         if (!desc) {
@@ -231,7 +229,7 @@ struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
         }
         init_one_irq_desc(irq, desc, node);
 
-        irq_desc_ptrs[irq] = desc;
+        set_irq_desc(irq, desc);
 
 out_unlock:
         raw_spin_unlock_irqrestore(&sparse_irq_lock, flags);
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index b2821f070a3d..c63f3bc88f0b 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -21,11 +21,7 @@ extern void clear_kstat_irqs(struct irq_desc *desc);
 extern raw_spinlock_t sparse_irq_lock;
 
 #ifdef CONFIG_SPARSE_IRQ
-/* irq_desc_ptrs allocated at boot time */
-extern struct irq_desc **irq_desc_ptrs;
-#else
-/* irq_desc_ptrs is a fixed size array */
-extern struct irq_desc *irq_desc_ptrs[NR_IRQS];
+void replace_irq_desc(unsigned int irq, struct irq_desc *desc);
 #endif
 
 #ifdef CONFIG_PROC_FS
diff --git a/kernel/irq/numa_migrate.c b/kernel/irq/numa_migrate.c
index 26bac9d8f860..963559dbd858 100644
--- a/kernel/irq/numa_migrate.c
+++ b/kernel/irq/numa_migrate.c
@@ -70,7 +70,7 @@ static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
         raw_spin_lock_irqsave(&sparse_irq_lock, flags);
 
         /* We have to check it to avoid races with another CPU */
-        desc = irq_desc_ptrs[irq];
+        desc = irq_to_desc(irq);
 
         if (desc && old_desc != desc)
                 goto out_unlock;
@@ -90,7 +90,7 @@ static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
                 goto out_unlock;
         }
 
-        irq_desc_ptrs[irq] = desc;
+        replace_irq_desc(irq, desc);
         raw_spin_unlock_irqrestore(&sparse_irq_lock, flags);
 
         /* free the old one */