powerpc/86xx: Renaming following split of GE Fanuc joint venture
[safe/jmp/linux-2.6] / arch / powerpc / kernel / irq.c
index c2b84c6..64f6f20 100644 (file)
@@ -7,7 +7,6 @@
  *    Copyright (C) 1996-2001 Cort Dougan
  *  Adapted for Power Macintosh by Paul Mackerras
  *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
- *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -53,6 +52,8 @@
 #include <linux/mutex.h>
 #include <linux/bootmem.h>
 #include <linux/pci.h>
+#include <linux/debugfs.h>
+#include <linux/perf_event.h>
 
 #include <asm/uaccess.h>
 #include <asm/system.h>
 #include <asm/firmware.h>
 #include <asm/lv1call.h>
 #endif
+#define CREATE_TRACE_POINTS
+#include <asm/trace.h>
+
+DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+EXPORT_PER_CPU_SYMBOL(irq_stat);
 
 int __irq_offset_value;
-static int ppc_spurious_interrupts;
 
 #ifdef CONFIG_PPC32
 EXPORT_SYMBOL(__irq_offset_value);
 atomic_t ppc_n_lost_interrupts;
 
-#ifndef CONFIG_PPC_MERGE
-#define NR_MASK_WORDS  ((NR_IRQS + 31) / 32)
-unsigned long ppc_cached_irq_mask[NR_MASK_WORDS];
-#endif
-
 #ifdef CONFIG_TAU_INT
 extern int tau_initialized;
 extern int tau_interrupts(int);
 #endif
 #endif /* CONFIG_PPC32 */
 
-#if defined(CONFIG_SMP) && !defined(CONFIG_PPC_MERGE)
-extern atomic_t ipi_recv;
-extern atomic_t ipi_sent;
-#endif
-
 #ifdef CONFIG_PPC64
+
+#ifndef CONFIG_SPARSE_IRQ
 EXPORT_SYMBOL(irq_desc);
+#endif
 
 int distribute_irqs = 1;
 
-static inline unsigned long get_hard_enabled(void)
+static inline notrace unsigned long get_hard_enabled(void)
 {
        unsigned long enabled;
 
@@ -108,13 +106,13 @@ static inline unsigned long get_hard_enabled(void)
        return enabled;
 }
 
-static inline void set_soft_enabled(unsigned long enable)
+static inline notrace void set_soft_enabled(unsigned long enable)
 {
        __asm__ __volatile__("stb %0,%1(13)"
        : : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
 }
 
-void local_irq_restore(unsigned long en)
+notrace void raw_local_irq_restore(unsigned long en)
 {
        /*
         * get_paca()->soft_enabled = en;
@@ -127,6 +125,7 @@ void local_irq_restore(unsigned long en)
        if (!en)
                return;
 
+#ifdef CONFIG_PPC_STD_MMU_64
        if (firmware_has_feature(FW_FEATURE_ISERIES)) {
                /*
                 * Do we need to disable preemption here?  Not really: in the
@@ -143,7 +142,12 @@ void local_irq_restore(unsigned long en)
                 */
                if (local_paca->lppaca_ptr->int_dword.any_int)
                        iseries_handle_interrupts();
-               return;
+       }
+#endif /* CONFIG_PPC_STD_MMU_64 */
+
+       if (test_perf_event_pending()) {
+               clear_perf_event_pending();
+               perf_event_do_pending();
        }
 
        /*
@@ -175,87 +179,138 @@ void local_irq_restore(unsigned long en)
 
        __hard_irq_enable();
 }
+EXPORT_SYMBOL(raw_local_irq_restore);
 #endif /* CONFIG_PPC64 */
 
+static int show_other_interrupts(struct seq_file *p, int prec)
+{
+       int j;
+
+#if defined(CONFIG_PPC32) && defined(CONFIG_TAU_INT)
+       if (tau_initialized) {
+               seq_printf(p, "%*s: ", prec, "TAU");
+               for_each_online_cpu(j)
+                       seq_printf(p, "%10u ", tau_interrupts(j));
+               seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
+       }
+#endif /* CONFIG_PPC32 && CONFIG_TAU_INT */
+
+       seq_printf(p, "%*s: ", prec, "LOC");
+       for_each_online_cpu(j)
+               seq_printf(p, "%10u ", per_cpu(irq_stat, j).timer_irqs);
+        seq_printf(p, "  Local timer interrupts\n");
+
+       seq_printf(p, "%*s: ", prec, "SPU");
+       for_each_online_cpu(j)
+               seq_printf(p, "%10u ", per_cpu(irq_stat, j).spurious_irqs);
+       seq_printf(p, "  Spurious interrupts\n");
+
+       seq_printf(p, "%*s: ", prec, "CNT");
+       for_each_online_cpu(j)
+               seq_printf(p, "%10u ", per_cpu(irq_stat, j).pmu_irqs);
+       seq_printf(p, "  Performance monitoring interrupts\n");
+
+       seq_printf(p, "%*s: ", prec, "MCE");
+       for_each_online_cpu(j)
+               seq_printf(p, "%10u ", per_cpu(irq_stat, j).mce_exceptions);
+       seq_printf(p, "  Machine check exceptions\n");
+
+       return 0;
+}
+
 int show_interrupts(struct seq_file *p, void *v)
 {
-       int i = *(loff_t *)v, j;
+       unsigned long flags, any_count = 0;
+       int i = *(loff_t *) v, j, prec;
        struct irqaction *action;
-       irq_desc_t *desc;
-       unsigned long flags;
+       struct irq_desc *desc;
+
+       if (i > nr_irqs)
+               return 0;
 
+       for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
+               j *= 10;
+
+       if (i == nr_irqs)
+               return show_other_interrupts(p, prec);
+
+       /* print header */
        if (i == 0) {
-               seq_puts(p, "           ");
+               seq_printf(p, "%*s", prec + 8, "");
                for_each_online_cpu(j)
-                       seq_printf(p, "CPU%d       ", j);
+                       seq_printf(p, "CPU%-8d", j);
                seq_putc(p, '\n');
        }
 
-       if (i < NR_IRQS) {
-               desc = get_irq_desc(i);
-               spin_lock_irqsave(&desc->lock, flags);
-               action = desc->action;
-               if (!action || !action->handler)
-                       goto skip;
-               seq_printf(p, "%3d: ", i);
-#ifdef CONFIG_SMP
-               for_each_online_cpu(j)
-                       seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
-#else
-               seq_printf(p, "%10u ", kstat_irqs(i));
-#endif /* CONFIG_SMP */
-               if (desc->chip)
-                       seq_printf(p, " %s ", desc->chip->typename);
-               else
-                       seq_puts(p, "  None      ");
-               seq_printf(p, "%s", (desc->status & IRQ_LEVEL) ? "Level " : "Edge  ");
-               seq_printf(p, "    %s", action->name);
-               for (action = action->next; action; action = action->next)
+       desc = irq_to_desc(i);
+       if (!desc)
+               return 0;
+
+       raw_spin_lock_irqsave(&desc->lock, flags);
+       for_each_online_cpu(j)
+               any_count |= kstat_irqs_cpu(i, j);
+       action = desc->action;
+       if (!action && !any_count)
+               goto out;
+
+       seq_printf(p, "%*d: ", prec, i);
+       for_each_online_cpu(j)
+               seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
+
+       if (desc->chip)
+               seq_printf(p, "  %-16s", desc->chip->name);
+       else
+               seq_printf(p, "  %-16s", "None");
+       seq_printf(p, " %-8s", (desc->status & IRQ_LEVEL) ? "Level" : "Edge");
+
+       if (action) {
+               seq_printf(p, "     %s", action->name);
+               while ((action = action->next) != NULL)
                        seq_printf(p, ", %s", action->name);
-               seq_putc(p, '\n');
-skip:
-               spin_unlock_irqrestore(&desc->lock, flags);
-       } else if (i == NR_IRQS) {
-#ifdef CONFIG_PPC32
-#ifdef CONFIG_TAU_INT
-               if (tau_initialized){
-                       seq_puts(p, "TAU: ");
-                       for_each_online_cpu(j)
-                               seq_printf(p, "%10u ", tau_interrupts(j));
-                       seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
-               }
-#endif
-#if defined(CONFIG_SMP) && !defined(CONFIG_PPC_MERGE)
-               /* should this be per processor send/receive? */
-               seq_printf(p, "IPI (recv/sent): %10u/%u\n",
-                               atomic_read(&ipi_recv), atomic_read(&ipi_sent));
-#endif
-#endif /* CONFIG_PPC32 */
-               seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
        }
+
+       seq_putc(p, '\n');
+out:
+       raw_spin_unlock_irqrestore(&desc->lock, flags);
        return 0;
 }
 
+/*
+ * /proc/stat helpers
+ */
+u64 arch_irq_stat_cpu(unsigned int cpu)
+{
+       u64 sum = per_cpu(irq_stat, cpu).timer_irqs;
+
+       sum += per_cpu(irq_stat, cpu).pmu_irqs;
+       sum += per_cpu(irq_stat, cpu).mce_exceptions;
+       sum += per_cpu(irq_stat, cpu).spurious_irqs;
+
+       return sum;
+}
+
 #ifdef CONFIG_HOTPLUG_CPU
 void fixup_irqs(cpumask_t map)
 {
+       struct irq_desc *desc;
        unsigned int irq;
        static int warned;
 
        for_each_irq(irq) {
                cpumask_t mask;
 
-               if (irq_desc[irq].status & IRQ_PER_CPU)
+               desc = irq_to_desc(irq);
+               if (desc && desc->status & IRQ_PER_CPU)
                        continue;
 
-               cpus_and(mask, irq_desc[irq].affinity, map);
+               cpumask_and(&mask, desc->affinity, &map);
                if (any_online_cpu(mask) == NR_CPUS) {
                        printk("Breaking affinity for irq %i\n", irq);
                        mask = map;
                }
-               if (irq_desc[irq].chip->set_affinity)
-                       irq_desc[irq].chip->set_affinity(irq, mask);
-               else if (irq_desc[irq].action && !(warned++))
+               if (desc->chip->set_affinity)
+                       desc->chip->set_affinity(irq, &mask);
+               else if (desc->action && !(warned++))
                        printk("Cannot set affinity for irq %i\n", irq);
        }
 
@@ -265,64 +320,89 @@ void fixup_irqs(cpumask_t map)
 }
 #endif
 
-void do_IRQ(struct pt_regs *regs)
-{
-       struct pt_regs *old_regs = set_irq_regs(regs);
-       unsigned int irq;
 #ifdef CONFIG_IRQSTACKS
+static inline void handle_one_irq(unsigned int irq)
+{
        struct thread_info *curtp, *irqtp;
-#endif
+       unsigned long saved_sp_limit;
+       struct irq_desc *desc;
 
-        irq_enter();
+       /* Switch to the irq stack to handle this */
+       curtp = current_thread_info();
+       irqtp = hardirq_ctx[smp_processor_id()];
 
+       if (curtp == irqtp) {
+               /* We're already on the irq stack, just handle it */
+               generic_handle_irq(irq);
+               return;
+       }
+
+       desc = irq_to_desc(irq);
+       saved_sp_limit = current->thread.ksp_limit;
+
+       irqtp->task = curtp->task;
+       irqtp->flags = 0;
+
+       /* Copy the softirq bits in preempt_count so that the
+        * softirq checks work in the hardirq context. */
+       irqtp->preempt_count = (irqtp->preempt_count & ~SOFTIRQ_MASK) |
+                              (curtp->preempt_count & SOFTIRQ_MASK);
+
+       current->thread.ksp_limit = (unsigned long)irqtp +
+               _ALIGN_UP(sizeof(struct thread_info), 16);
+
+       call_handle_irq(irq, desc, irqtp, desc->handle_irq);
+       current->thread.ksp_limit = saved_sp_limit;
+       irqtp->task = NULL;
+
+       /* Set any flag that may have been set on the
+        * alternate stack
+        */
+       if (irqtp->flags)
+               set_bits(irqtp->flags, &curtp->flags);
+}
+#else
+static inline void handle_one_irq(unsigned int irq)
+{
+       generic_handle_irq(irq);
+}
+#endif
+
+static inline void check_stack_overflow(void)
+{
 #ifdef CONFIG_DEBUG_STACKOVERFLOW
-       /* Debugging check for stack overflow: is there less than 2KB free? */
-       {
-               long sp;
+       long sp;
 
-               sp = __get_SP() & (THREAD_SIZE-1);
+       sp = __get_SP() & (THREAD_SIZE-1);
 
-               if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
-                       printk("do_IRQ: stack overflow: %ld\n",
-                               sp - sizeof(struct thread_info));
-                       dump_stack();
-               }
+       /* check for stack overflow: is there less than 2KB free? */
+       if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
+               printk("do_IRQ: stack overflow: %ld\n",
+                       sp - sizeof(struct thread_info));
+               dump_stack();
        }
 #endif
+}
+
+void do_IRQ(struct pt_regs *regs)
+{
+       struct pt_regs *old_regs = set_irq_regs(regs);
+       unsigned int irq;
+
+       trace_irq_entry(regs);
+
+       irq_enter();
+
+       check_stack_overflow();
 
-       /*
-        * Every platform is required to implement ppc_md.get_irq.
-        * This function will either return an irq number or NO_IRQ to
-        * indicate there are no more pending.
-        * The value NO_IRQ_IGNORE is for buggy hardware and means that this
-        * IRQ has already been handled. -- Tom
-        */
        irq = ppc_md.get_irq();
 
-       if (irq != NO_IRQ && irq != NO_IRQ_IGNORE) {
-#ifdef CONFIG_IRQSTACKS
-               /* Switch to the irq stack to handle this */
-               curtp = current_thread_info();
-               irqtp = hardirq_ctx[smp_processor_id()];
-               if (curtp != irqtp) {
-                       struct irq_desc *desc = irq_desc + irq;
-                       void *handler = desc->handle_irq;
-                       if (handler == NULL)
-                               handler = &__do_IRQ;
-                       irqtp->task = curtp->task;
-                       irqtp->flags = 0;
-                       call_handle_irq(irq, desc, irqtp, handler);
-                       irqtp->task = NULL;
-                       if (irqtp->flags)
-                               set_bits(irqtp->flags, &curtp->flags);
-               } else
-#endif
-                       generic_handle_irq(irq);
-       } else if (irq != NO_IRQ_IGNORE)
-               /* That's not SMP safe ... but who cares ? */
-               ppc_spurious_interrupts++;
+       if (irq != NO_IRQ && irq != NO_IRQ_IGNORE)
+               handle_one_irq(irq);
+       else if (irq != NO_IRQ_IGNORE)
+               __get_cpu_var(irq_stat).spurious_irqs++;
 
-        irq_exit();
+       irq_exit();
        set_irq_regs(old_regs);
 
 #ifdef CONFIG_PPC_ISERIES
@@ -333,16 +413,50 @@ void do_IRQ(struct pt_regs *regs)
                timer_interrupt(regs);
        }
 #endif
+
+       trace_irq_exit(regs);
 }
 
 void __init init_IRQ(void)
 {
-       ppc_md.init_IRQ();
-#ifdef CONFIG_PPC64
+       if (ppc_md.init_IRQ)
+               ppc_md.init_IRQ();
+
+       exc_lvl_ctx_init();
+
        irq_ctx_init();
-#endif
 }
 
+#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
+struct thread_info   *critirq_ctx[NR_CPUS] __read_mostly;
+struct thread_info    *dbgirq_ctx[NR_CPUS] __read_mostly;
+struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly;
+
+void exc_lvl_ctx_init(void)
+{
+       struct thread_info *tp;
+       int i;
+
+       for_each_possible_cpu(i) {
+               memset((void *)critirq_ctx[i], 0, THREAD_SIZE);
+               tp = critirq_ctx[i];
+               tp->cpu = i;
+               tp->preempt_count = 0;
+
+#ifdef CONFIG_BOOKE
+               memset((void *)dbgirq_ctx[i], 0, THREAD_SIZE);
+               tp = dbgirq_ctx[i];
+               tp->cpu = i;
+               tp->preempt_count = 0;
+
+               memset((void *)mcheckirq_ctx[i], 0, THREAD_SIZE);
+               tp = mcheckirq_ctx[i];
+               tp->cpu = i;
+               tp->preempt_count = HARDIRQ_OFFSET;
+#endif
+       }
+}
+#endif
 
 #ifdef CONFIG_IRQSTACKS
 struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;
@@ -357,7 +471,7 @@ void irq_ctx_init(void)
                memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
                tp = softirq_ctx[i];
                tp->cpu = i;
-               tp->preempt_count = SOFTIRQ_OFFSET;
+               tp->preempt_count = 0;
 
                memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
                tp = hardirq_ctx[i];
@@ -369,11 +483,15 @@ void irq_ctx_init(void)
 static inline void do_softirq_onstack(void)
 {
        struct thread_info *curtp, *irqtp;
+       unsigned long saved_sp_limit = current->thread.ksp_limit;
 
        curtp = current_thread_info();
        irqtp = softirq_ctx[smp_processor_id()];
        irqtp->task = curtp->task;
+       current->thread.ksp_limit = (unsigned long)irqtp +
+                                   _ALIGN_UP(sizeof(struct thread_info), 16);
        call_do_softirq(irqtp);
+       current->thread.ksp_limit = saved_sp_limit;
        irqtp->task = NULL;
 }
 
@@ -395,19 +513,16 @@ void do_softirq(void)
 
        local_irq_restore(flags);
 }
-EXPORT_SYMBOL(do_softirq);
 
 
 /*
  * IRQ controller and virtual interrupts
  */
 
-#ifdef CONFIG_PPC_MERGE
-
 static LIST_HEAD(irq_hosts);
-static DEFINE_SPINLOCK(irq_big_lock);
-static DEFINE_PER_CPU(unsigned int, irq_radix_reader);
-static unsigned int irq_radix_writer;
+static DEFINE_RAW_SPINLOCK(irq_big_lock);
+static unsigned int revmap_trees_allocated;
+static DEFINE_MUTEX(revmap_trees_mutex);
 struct irq_map_entry irq_map[NR_IRQS];
 static unsigned int irq_virq_count = NR_IRQS;
 static struct irq_host *irq_default_host;
@@ -418,7 +533,13 @@ irq_hw_number_t virq_to_hw(unsigned int virq)
 }
 EXPORT_SYMBOL_GPL(virq_to_hw);
 
-struct irq_host *irq_alloc_host(unsigned int revmap_type,
+static int default_irq_host_match(struct irq_host *h, struct device_node *np)
+{
+       return h->of_node != NULL && h->of_node == np;
+}
+
+struct irq_host *irq_alloc_host(struct device_node *of_node,
+                               unsigned int revmap_type,
                                unsigned int revmap_arg,
                                struct irq_host_ops *ops,
                                irq_hw_number_t inval_irq)
@@ -432,13 +553,7 @@ struct irq_host *irq_alloc_host(unsigned int revmap_type,
        /* Allocate structure and revmap table if using linear mapping */
        if (revmap_type == IRQ_HOST_MAP_LINEAR)
                size += revmap_arg * sizeof(unsigned int);
-       if (mem_init_done)
-               host = kzalloc(size, GFP_KERNEL);
-       else {
-               host = alloc_bootmem(size);
-               if (host)
-                       memset(host, 0, size);
-       }
+       host = zalloc_maybe_bootmem(size, GFP_KERNEL);
        if (host == NULL)
                return NULL;
 
@@ -446,15 +561,19 @@ struct irq_host *irq_alloc_host(unsigned int revmap_type,
        host->revmap_type = revmap_type;
        host->inval_irq = inval_irq;
        host->ops = ops;
+       host->of_node = of_node_get(of_node);
+
+       if (host->ops->match == NULL)
+               host->ops->match = default_irq_host_match;
 
-       spin_lock_irqsave(&irq_big_lock, flags);
+       raw_spin_lock_irqsave(&irq_big_lock, flags);
 
        /* If it's a legacy controller, check for duplicates and
         * mark it as allocated (we use irq 0 host pointer for that
         */
        if (revmap_type == IRQ_HOST_MAP_LEGACY) {
                if (irq_map[0].host != NULL) {
-                       spin_unlock_irqrestore(&irq_big_lock, flags);
+                       raw_spin_unlock_irqrestore(&irq_big_lock, flags);
                        /* If we are early boot, we can't free the structure,
                         * too bad...
                         * this will be fixed once slab is made available early
@@ -468,7 +587,7 @@ struct irq_host *irq_alloc_host(unsigned int revmap_type,
        }
 
        list_add(&host->link, &irq_hosts);
-       spin_unlock_irqrestore(&irq_big_lock, flags);
+       raw_spin_unlock_irqrestore(&irq_big_lock, flags);
 
        /* Additional setups per revmap type */
        switch(revmap_type) {
@@ -477,17 +596,17 @@ struct irq_host *irq_alloc_host(unsigned int revmap_type,
                host->inval_irq = 0;
                /* setup us as the host for all legacy interrupts */
                for (i = 1; i < NUM_ISA_INTERRUPTS; i++) {
-                       irq_map[i].hwirq = 0;
+                       irq_map[i].hwirq = i;
                        smp_wmb();
                        irq_map[i].host = host;
                        smp_wmb();
 
                        /* Clear norequest flags */
-                       get_irq_desc(i)->status &= ~IRQ_NOREQUEST;
+                       irq_to_desc(i)->status &= ~IRQ_NOREQUEST;
 
                        /* Legacy flags are left to default at this point,
                         * one can then use irq_create_mapping() to
-                        * explicitely change them
+                        * explicitly change them
                         */
                        ops->map(host, i, i);
                }
@@ -519,13 +638,13 @@ struct irq_host *irq_find_host(struct device_node *node)
         * the absence of a device node. This isn't a problem so far
         * yet though...
         */
-       spin_lock_irqsave(&irq_big_lock, flags);
+       raw_spin_lock_irqsave(&irq_big_lock, flags);
        list_for_each_entry(h, &irq_hosts, link)
-               if (h->ops->match == NULL || h->ops->match(h, node)) {
+               if (h->ops->match(h, node)) {
                        found = h;
                        break;
                }
-       spin_unlock_irqrestore(&irq_big_lock, flags);
+       raw_spin_unlock_irqrestore(&irq_big_lock, flags);
        return found;
 }
 EXPORT_SYMBOL_GPL(irq_find_host);
@@ -546,57 +665,60 @@ void irq_set_virq_count(unsigned int count)
                irq_virq_count = count;
 }
 
-/* radix tree not lockless safe ! we use a brlock-type mecanism
- * for now, until we can use a lockless radix tree
- */
-static void irq_radix_wrlock(unsigned long *flags)
+static int irq_setup_virq(struct irq_host *host, unsigned int virq,
+                           irq_hw_number_t hwirq)
 {
-       unsigned int cpu, ok;
+       struct irq_desc *desc;
 
-       spin_lock_irqsave(&irq_big_lock, *flags);
-       irq_radix_writer = 1;
-       smp_mb();
-       do {
-               barrier();
-               ok = 1;
-               for_each_possible_cpu(cpu) {
-                       if (per_cpu(irq_radix_reader, cpu)) {
-                               ok = 0;
-                               break;
-                       }
-               }
-               if (!ok)
-                       cpu_relax();
-       } while(!ok);
-}
+       desc = irq_to_desc_alloc_node(virq, 0);
+       if (!desc) {
+               pr_debug("irq: -> allocating desc failed\n");
+               goto error;
+       }
 
-static void irq_radix_wrunlock(unsigned long flags)
-{
-       smp_wmb();
-       irq_radix_writer = 0;
-       spin_unlock_irqrestore(&irq_big_lock, flags);
-}
+       /* Clear IRQ_NOREQUEST flag */
+       desc->status &= ~IRQ_NOREQUEST;
 
-static void irq_radix_rdlock(unsigned long *flags)
-{
-       local_irq_save(*flags);
-       __get_cpu_var(irq_radix_reader) = 1;
-       smp_mb();
-       if (likely(irq_radix_writer == 0))
-               return;
-       __get_cpu_var(irq_radix_reader) = 0;
+       /* map it */
        smp_wmb();
-       spin_lock(&irq_big_lock);
-       __get_cpu_var(irq_radix_reader) = 1;
-       spin_unlock(&irq_big_lock);
+       irq_map[virq].hwirq = hwirq;
+       smp_mb();
+
+       if (host->ops->map(host, virq, hwirq)) {
+               pr_debug("irq: -> mapping failed, freeing\n");
+               goto error;
+       }
+
+       return 0;
+
+error:
+       irq_free_virt(virq, 1);
+       return -1;
 }
 
-static void irq_radix_rdunlock(unsigned long flags)
+unsigned int irq_create_direct_mapping(struct irq_host *host)
 {
-       __get_cpu_var(irq_radix_reader) = 0;
-       local_irq_restore(flags);
-}
+       unsigned int virq;
+
+       if (host == NULL)
+               host = irq_default_host;
+
+       BUG_ON(host == NULL);
+       WARN_ON(host->revmap_type != IRQ_HOST_MAP_NOMAP);
+
+       virq = irq_alloc_virt(host, 1, 0);
+       if (virq == NO_IRQ) {
+               pr_debug("irq: create_direct virq allocation failed\n");
+               return NO_IRQ;
+       }
+
+       pr_debug("irq: create_direct obtained virq %d\n", virq);
+
+       if (irq_setup_virq(host, virq, virq))
+               return NO_IRQ;
 
+       return virq;
+}
 
 unsigned int irq_create_mapping(struct irq_host *host,
                                irq_hw_number_t hwirq)
@@ -643,26 +765,19 @@ unsigned int irq_create_mapping(struct irq_host *host,
                        return NO_IRQ;
                }
        }
-       pr_debug("irq: -> obtained virq %d\n", virq);
-
-       /* Clear IRQ_NOREQUEST flag */
-       get_irq_desc(virq)->status &= ~IRQ_NOREQUEST;
 
-       /* map it */
-       smp_wmb();
-       irq_map[virq].hwirq = hwirq;
-       smp_mb();
-       if (host->ops->map(host, virq, hwirq)) {
-               pr_debug("irq: -> mapping failed, freeing\n");
-               irq_free_virt(virq, 1);
+       if (irq_setup_virq(host, virq, hwirq))
                return NO_IRQ;
-       }
+
+       printk(KERN_DEBUG "irq: irq %lu on host %s mapped to virtual irq %u\n",
+               hwirq, host->of_node ? host->of_node->full_name : "null", virq);
+
        return virq;
 }
 EXPORT_SYMBOL_GPL(irq_create_mapping);
 
 unsigned int irq_create_of_mapping(struct device_node *controller,
-                                  u32 *intspec, unsigned int intsize)
+                                  const u32 *intspec, unsigned int intsize)
 {
        struct irq_host *host;
        irq_hw_number_t hwirq;
@@ -695,7 +810,7 @@ unsigned int irq_create_of_mapping(struct device_node *controller,
 
        /* Set type if specified and different than the current one */
        if (type != IRQ_TYPE_NONE &&
-           type != (get_irq_desc(virq)->status & IRQF_TRIGGER_MASK))
+           type != (irq_to_desc(virq)->status & IRQF_TRIGGER_MASK))
                set_irq_type(virq, type);
        return virq;
 }
@@ -717,7 +832,6 @@ void irq_dispose_mapping(unsigned int virq)
 {
        struct irq_host *host;
        irq_hw_number_t hwirq;
-       unsigned long flags;
 
        if (virq == NO_IRQ)
                return;
@@ -750,12 +864,16 @@ void irq_dispose_mapping(unsigned int virq)
                        host->revmap_data.linear.revmap[hwirq] = NO_IRQ;
                break;
        case IRQ_HOST_MAP_TREE:
-               /* Check if radix tree allocated yet */
-               if (host->revmap_data.tree.gfp_mask == 0)
+               /*
+                * Check if radix tree allocated yet, if not then nothing to
+                * remove.
+                */
+               smp_rmb();
+               if (revmap_trees_allocated < 1)
                        break;
-               irq_radix_wrlock(&flags);
+               mutex_lock(&revmap_trees_mutex);
                radix_tree_delete(&host->revmap_data.tree, hwirq);
-               irq_radix_wrunlock(flags);
+               mutex_unlock(&revmap_trees_mutex);
                break;
        }
 
@@ -764,7 +882,7 @@ void irq_dispose_mapping(unsigned int virq)
        irq_map[virq].hwirq = host->inval_irq;
 
        /* Set some flags */
-       get_irq_desc(virq)->status |= IRQ_NOREQUEST;
+       irq_to_desc(virq)->status |= IRQ_NOREQUEST;
 
        /* Free it */
        irq_free_virt(virq, 1);
@@ -804,43 +922,62 @@ unsigned int irq_find_mapping(struct irq_host *host,
 EXPORT_SYMBOL_GPL(irq_find_mapping);
 
 
-unsigned int irq_radix_revmap(struct irq_host *host,
-                             irq_hw_number_t hwirq)
+unsigned int irq_radix_revmap_lookup(struct irq_host *host,
+                                    irq_hw_number_t hwirq)
 {
-       struct radix_tree_root *tree;
        struct irq_map_entry *ptr;
        unsigned int virq;
-       unsigned long flags;
 
        WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE);
 
-       /* Check if the radix tree exist yet. We test the value of
-        * the gfp_mask for that. Sneaky but saves another int in the
-        * structure. If not, we fallback to slow mode
+       /*
+        * Check if the radix tree exists and has bee initialized.
+        * If not, we fallback to slow mode
         */
-       tree = &host->revmap_data.tree;
-       if (tree->gfp_mask == 0)
+       if (revmap_trees_allocated < 2)
                return irq_find_mapping(host, hwirq);
 
        /* Now try to resolve */
-       irq_radix_rdlock(&flags);
-       ptr = radix_tree_lookup(tree, hwirq);
-       irq_radix_rdunlock(flags);
+       /*
+        * No rcu_read_lock(ing) needed, the ptr returned can't go under us
+        * as it's referencing an entry in the static irq_map table.
+        */
+       ptr = radix_tree_lookup(&host->revmap_data.tree, hwirq);
 
-       /* Found it, return */
-       if (ptr) {
+       /*
+        * If found in radix tree, then fine.
+        * Else fallback to linear lookup - this should not happen in practice
+        * as it means that we failed to insert the node in the radix tree.
+        */
+       if (ptr)
                virq = ptr - irq_map;
-               return virq;
-       }
+       else
+               virq = irq_find_mapping(host, hwirq);
+
+       return virq;
+}
+
+void irq_radix_revmap_insert(struct irq_host *host, unsigned int virq,
+                            irq_hw_number_t hwirq)
+{
+
+       WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE);
+
+       /*
+        * Check if the radix tree exists yet.
+        * If not, then the irq will be inserted into the tree when it gets
+        * initialized.
+        */
+       smp_rmb();
+       if (revmap_trees_allocated < 1)
+               return;
 
-       /* If not there, try to insert it */
-       virq = irq_find_mapping(host, hwirq);
        if (virq != NO_IRQ) {
-               irq_radix_wrlock(&flags);
-               radix_tree_insert(tree, hwirq, &irq_map[virq]);
-               irq_radix_wrunlock(flags);
+               mutex_lock(&revmap_trees_mutex);
+               radix_tree_insert(&host->revmap_data.tree, hwirq,
+                                 &irq_map[virq]);
+               mutex_unlock(&revmap_trees_mutex);
        }
-       return virq;
 }
 
 unsigned int irq_linear_revmap(struct irq_host *host,
@@ -876,7 +1013,7 @@ unsigned int irq_alloc_virt(struct irq_host *host,
        if (count == 0 || count > (irq_virq_count - NUM_ISA_INTERRUPTS))
                return NO_IRQ;
 
-       spin_lock_irqsave(&irq_big_lock, flags);
+       raw_spin_lock_irqsave(&irq_big_lock, flags);
 
        /* Use hint for 1 interrupt if any */
        if (count == 1 && hint >= NUM_ISA_INTERRUPTS &&
@@ -900,7 +1037,7 @@ unsigned int irq_alloc_virt(struct irq_host *host,
                }
        }
        if (found == NO_IRQ) {
-               spin_unlock_irqrestore(&irq_big_lock, flags);
+               raw_spin_unlock_irqrestore(&irq_big_lock, flags);
                return NO_IRQ;
        }
  hint_found:
@@ -909,7 +1046,7 @@ unsigned int irq_alloc_virt(struct irq_host *host,
                smp_wmb();
                irq_map[i].host = host;
        }
-       spin_unlock_irqrestore(&irq_big_lock, flags);
+       raw_spin_unlock_irqrestore(&irq_big_lock, flags);
        return found;
 }
 
@@ -921,7 +1058,7 @@ void irq_free_virt(unsigned int virq, unsigned int count)
        WARN_ON (virq < NUM_ISA_INTERRUPTS);
        WARN_ON (count == 0 || (virq + count) > irq_virq_count);
 
-       spin_lock_irqsave(&irq_big_lock, flags);
+       raw_spin_lock_irqsave(&irq_big_lock, flags);
        for (i = virq; i < (virq + count); i++) {
                struct irq_host *host;
 
@@ -934,35 +1071,140 @@ void irq_free_virt(unsigned int virq, unsigned int count)
                smp_wmb();
                irq_map[i].host = NULL;
        }
-       spin_unlock_irqrestore(&irq_big_lock, flags);
+       raw_spin_unlock_irqrestore(&irq_big_lock, flags);
 }
 
-void irq_early_init(void)
+int arch_early_irq_init(void)
 {
-       unsigned int i;
+       struct irq_desc *desc;
+       int i;
+
+       for (i = 0; i < NR_IRQS; i++) {
+               desc = irq_to_desc(i);
+               if (desc)
+                       desc->status |= IRQ_NOREQUEST;
+       }
+
+       return 0;
+}
 
-       for (i = 0; i < NR_IRQS; i++)
-               get_irq_desc(i)->status |= IRQ_NOREQUEST;
+int arch_init_chip_data(struct irq_desc *desc, int node)
+{
+       desc->status |= IRQ_NOREQUEST;
+       return 0;
 }
 
 /* We need to create the radix trees late */
 static int irq_late_init(void)
 {
        struct irq_host *h;
-       unsigned long flags;
+       unsigned int i;
 
-       irq_radix_wrlock(&flags);
+       /*
+        * No mutual exclusion with respect to accessors of the tree is needed
+        * here as the synchronization is done via the state variable
+        * revmap_trees_allocated.
+        */
        list_for_each_entry(h, &irq_hosts, link) {
                if (h->revmap_type == IRQ_HOST_MAP_TREE)
-                       INIT_RADIX_TREE(&h->revmap_data.tree, GFP_ATOMIC);
+                       INIT_RADIX_TREE(&h->revmap_data.tree, GFP_KERNEL);
+       }
+
+       /*
+        * Make sure the radix trees inits are visible before setting
+        * the flag
+        */
+       smp_wmb();
+       revmap_trees_allocated = 1;
+
+       /*
+        * Insert the reverse mapping for those interrupts already present
+        * in irq_map[].
+        */
+       mutex_lock(&revmap_trees_mutex);
+       for (i = 0; i < irq_virq_count; i++) {
+               if (irq_map[i].host &&
+                   (irq_map[i].host->revmap_type == IRQ_HOST_MAP_TREE))
+                       radix_tree_insert(&irq_map[i].host->revmap_data.tree,
+                                         irq_map[i].hwirq, &irq_map[i]);
        }
-       irq_radix_wrunlock(flags);
+       mutex_unlock(&revmap_trees_mutex);
+
+       /*
+        * Make sure the radix trees insertions are visible before setting
+        * the flag
+        */
+       smp_wmb();
+       revmap_trees_allocated = 2;
 
        return 0;
 }
 arch_initcall(irq_late_init);
 
-#endif /* CONFIG_PPC_MERGE */
+#ifdef CONFIG_VIRQ_DEBUG
+static int virq_debug_show(struct seq_file *m, void *private)
+{
+       unsigned long flags;
+       struct irq_desc *desc;
+       const char *p;
+       char none[] = "none";
+       int i;
+
+       seq_printf(m, "%-5s  %-7s  %-15s  %s\n", "virq", "hwirq",
+                     "chip name", "host name");
+
+       for (i = 1; i < nr_irqs; i++) {
+               desc = irq_to_desc(i);
+               if (!desc)
+                       continue;
+
+               raw_spin_lock_irqsave(&desc->lock, flags);
+
+               if (desc->action && desc->action->handler) {
+                       seq_printf(m, "%5d  ", i);
+                       seq_printf(m, "0x%05lx  ", virq_to_hw(i));
+
+                       if (desc->chip && desc->chip->name)
+                               p = desc->chip->name;
+                       else
+                               p = none;
+                       seq_printf(m, "%-15s  ", p);
+
+                       if (irq_map[i].host && irq_map[i].host->of_node)
+                               p = irq_map[i].host->of_node->full_name;
+                       else
+                               p = none;
+                       seq_printf(m, "%s\n", p);
+               }
+
+               raw_spin_unlock_irqrestore(&desc->lock, flags);
+       }
+
+       return 0;
+}
+
+static int virq_debug_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, virq_debug_show, inode->i_private);
+}
+
+static const struct file_operations virq_debug_fops = {
+       .open = virq_debug_open,
+       .read = seq_read,
+       .llseek = seq_lseek,
+       .release = single_release,
+};
+
+static int __init irq_debugfs_init(void)
+{
+       if (debugfs_create_file("virq_mapping", S_IRUGO, powerpc_debugfs_root,
+                                NULL, &virq_debug_fops) == NULL)
+               return -ENOMEM;
+
+       return 0;
+}
+__initcall(irq_debugfs_init);
+#endif /* CONFIG_VIRQ_DEBUG */
 
 #ifdef CONFIG_PPC64
 static int __init setup_noirqdistrib(char *str)