5 files changed, 83 insertions, 6 deletions

diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index faa1cf848bcd..45257475623c 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -116,7 +116,7 @@
 # define IRQ_EXIT_OFFSET HARDIRQ_OFFSET
 #endif
 
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS)
 extern void synchronize_irq(unsigned int irq);
 #else
 # define synchronize_irq(irq)   barrier()
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 8a9613d0c674..91bb76f44f14 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -59,6 +59,18 @@
 #define IRQF_NOBALANCING        0x00000800
 #define IRQF_IRQPOLL            0x00001000
 
+/*
+ * Bits used by threaded handlers:
+ * IRQTF_RUNTHREAD - signals that the interrupt handler thread should run
+ * IRQTF_DIED      - handler thread died
+ * IRQTF_WARNED    - warning "IRQ_WAKE_THREAD w/o thread_fn" has been printed
+ */
+enum {
+        IRQTF_RUNTHREAD,
+        IRQTF_DIED,
+        IRQTF_WARNED,
+};
+
 typedef irqreturn_t (*irq_handler_t)(int, void *);
 
 /**
@@ -71,6 +83,9 @@ typedef irqreturn_t (*irq_handler_t)(int, void *);
  * @next:       pointer to the next irqaction for shared interrupts
  * @irq:        interrupt number
  * @dir:        pointer to the proc/irq/NN/name entry
+ * @thread_fn:  interupt handler function for threaded interrupts
+ * @thread:     thread pointer for threaded interrupts
+ * @thread_flags:       flags related to @thread
  */
 struct irqaction {
         irq_handler_t handler;
@@ -81,18 +96,68 @@ struct irqaction {
         struct irqaction *next;
         int irq;
         struct proc_dir_entry *dir;
+        irq_handler_t thread_fn;
+        struct task_struct *thread;
+        unsigned long thread_flags;
 };
 
 extern irqreturn_t no_action(int cpl, void *dev_id);
-extern int __must_check request_irq(unsigned int, irq_handler_t handler,
-                       unsigned long, const char *, void *);
+
+#ifdef CONFIG_GENERIC_HARDIRQS
+extern int __must_check
+request_threaded_irq(unsigned int irq, irq_handler_t handler,
+                     irq_handler_t thread_fn,
+                     unsigned long flags, const char *name, void *dev);
+
+static inline int __must_check
+request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
+            const char *name, void *dev)
+{
+        return request_threaded_irq(irq, handler, NULL, flags, name, dev);
+}
+
+extern void exit_irq_thread(void);
+#else
+
+extern int __must_check
+request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
+            const char *name, void *dev);
+
+/*
+ * Special function to avoid ifdeffery in kernel/irq/devres.c which
+ * gets magically built by GENERIC_HARDIRQS=n architectures (sparc,
+ * m68k). I really love these $@%#!* obvious Makefile references:
+ * ../../../kernel/irq/devres.o
+ */
+static inline int __must_check
+request_threaded_irq(unsigned int irq, irq_handler_t handler,
+                     irq_handler_t thread_fn,
+                     unsigned long flags, const char *name, void *dev)
+{
+        return request_irq(irq, handler, flags, name, dev);
+}
+
+static inline void exit_irq_thread(void) { }
+#endif
+
 extern void free_irq(unsigned int, void *);
 
 struct device;
 
-extern int __must_check devm_request_irq(struct device *dev, unsigned int irq,
-                            irq_handler_t handler, unsigned long irqflags,
-                            const char *devname, void *dev_id);
+extern int __must_check
+devm_request_threaded_irq(struct device *dev, unsigned int irq,
+                          irq_handler_t handler, irq_handler_t thread_fn,
+                          unsigned long irqflags, const char *devname,
+                          void *dev_id);
+
+static inline int __must_check
+devm_request_irq(struct device *dev, unsigned int irq, irq_handler_t handler,
+                 unsigned long irqflags, const char *devname, void *dev_id)
+{
+        return devm_request_threaded_irq(dev, irq, handler, NULL, irqflags,
+                                         devname, dev_id);
+}
+
 extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id);
 
 /*
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 974890b3c52f..ca507c9426b0 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -22,6 +22,7 @@
 #include <linux/irqnr.h>
 #include <linux/errno.h>
 #include <linux/topology.h>
+#include <linux/wait.h>
 
 #include <asm/irq.h>
 #include <asm/ptrace.h>
@@ -158,6 +159,8 @@ struct irq_2_iommu;
  * @affinity:           IRQ affinity on SMP
  * @cpu:                cpu index useful for balancing
  * @pending_mask:       pending rebalanced interrupts
+ * @threads_active:     number of irqaction threads currently running
+ * @wait_for_threads:   wait queue for sync_irq to wait for threaded handlers
  * @dir:                /proc/irq/ procfs entry
  * @name:               flow handler name for /proc/interrupts output
  */
@@ -189,6 +192,8 @@ struct irq_desc {
         cpumask_var_t           pending_mask;
 #endif
 #endif
+        atomic_t                threads_active;
+        wait_queue_head_t       wait_for_threads;
 #ifdef CONFIG_PROC_FS
         struct proc_dir_entry   *dir;
 #endif
diff --git a/include/linux/irqreturn.h b/include/linux/irqreturn.h
index c5584ca5b8c9..819acaaac3f5 100644
--- a/include/linux/irqreturn.h
+++ b/include/linux/irqreturn.h
@@ -5,10 +5,12 @@
  * enum irqreturn
  * @IRQ_NONE            interrupt was not from this device
  * @IRQ_HANDLED         interrupt was handled by this device
+ * @IRQ_WAKE_THREAD     handler requests to wake the handler thread
  */
 enum irqreturn {
         IRQ_NONE,
         IRQ_HANDLED,
+        IRQ_WAKE_THREAD,
 };
 
 typedef enum irqreturn irqreturn_t;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b94f3541f67b..c96140210d1c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1294,6 +1294,11 @@ struct task_struct {
 /* Protection of (de-)allocation: mm, files, fs, tty, keyrings */
         spinlock_t alloc_lock;
 
+#ifdef CONFIG_GENERIC_HARDIRQS
+        /* IRQ handler threads */
+        struct irqaction *irqaction;
+#endif
+
         /* Protection of the PI data structures: */
         spinlock_t pi_lock;