1 /* 2 * linux/kernel/irq/handle.c 3 * 4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar 5 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King 6 * 7 * This file contains the core interrupt handling code. 8 * 9 * Detailed information is available in Documentation/DocBook/genericirq 10 * 11 */ 12 13 #include <linux/irq.h> 14 #include <linux/random.h> 15 #include <linux/sched.h> 16 #include <linux/interrupt.h> 17 #include <linux/kernel_stat.h> 18 19 #include <trace/events/irq.h> 20 21 #include "internals.h" 22 23 /** 24 * handle_bad_irq - handle spurious and unhandled irqs 25 * @irq: the interrupt number 26 * @desc: description of the interrupt 27 * 28 * Handles spurious and unhandled IRQ's. It also prints a debugmessage. 29 */ 30 void handle_bad_irq(unsigned int irq, struct irq_desc *desc) 31 { 32 print_irq_desc(irq, desc); 33 kstat_incr_irqs_this_cpu(irq, desc); 34 ack_bad_irq(irq); 35 } 36 37 /* 38 * Special, empty irq handler: 39 */ 40 irqreturn_t no_action(int cpl, void *dev_id) 41 { 42 return IRQ_NONE; 43 } 44 45 static void warn_no_thread(unsigned int irq, struct irqaction *action) 46 { 47 if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags)) 48 return; 49 50 printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD " 51 "but no thread function available.", irq, action->name); 52 } 53 54 /** 55 * handle_IRQ_event - irq action chain handler 56 * @irq: the interrupt number 57 * @action: the interrupt action chain for this irq 58 * 59 * Handles the action chain of an irq event 60 */ 61 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action) 62 { 63 irqreturn_t ret, retval = IRQ_NONE; 64 unsigned int status = 0; 65 66 do { 67 trace_irq_handler_entry(irq, action); 68 ret = action->handler(irq, action->dev_id); 69 trace_irq_handler_exit(irq, action, ret); 70 71 switch (ret) { 72 case IRQ_WAKE_THREAD: 73 /* 74 * Set result to handled so the spurious check 75 * does not trigger. 76 */ 77 ret = IRQ_HANDLED; 78 79 /* 80 * Catch drivers which return WAKE_THREAD but 81 * did not set up a thread function 82 */ 83 if (unlikely(!action->thread_fn)) { 84 warn_no_thread(irq, action); 85 break; 86 } 87 88 /* 89 * Wake up the handler thread for this 90 * action. In case the thread crashed and was 91 * killed we just pretend that we handled the 92 * interrupt. The hardirq handler above has 93 * disabled the device interrupt, so no irq 94 * storm is lurking. 95 */ 96 if (likely(!test_bit(IRQTF_DIED, 97 &action->thread_flags))) { 98 set_bit(IRQTF_RUNTHREAD, &action->thread_flags); 99 wake_up_process(action->thread); 100 } 101 102 /* Fall through to add to randomness */ 103 case IRQ_HANDLED: 104 status |= action->flags; 105 break; 106 107 default: 108 break; 109 } 110 111 retval |= ret; 112 action = action->next; 113 } while (action); 114 115 if (status & IRQF_SAMPLE_RANDOM) 116 add_interrupt_randomness(irq); 117 local_irq_disable(); 118 119 return retval; 120 } 121 122 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ 123 124 #ifdef CONFIG_ENABLE_WARN_DEPRECATED 125 # warning __do_IRQ is deprecated. Please convert to proper flow handlers 126 #endif 127 128 /** 129 * __do_IRQ - original all in one highlevel IRQ handler 130 * @irq: the interrupt number 131 * 132 * __do_IRQ handles all normal device IRQ's (the special 133 * SMP cross-CPU interrupts have their own specific 134 * handlers). 135 * 136 * This is the original x86 implementation which is used for every 137 * interrupt type. 138 */ 139 unsigned int __do_IRQ(unsigned int irq) 140 { 141 struct irq_desc *desc = irq_to_desc(irq); 142 struct irqaction *action; 143 unsigned int status; 144 145 kstat_incr_irqs_this_cpu(irq, desc); 146 147 if (CHECK_IRQ_PER_CPU(desc->status)) { 148 irqreturn_t action_ret; 149 150 /* 151 * No locking required for CPU-local interrupts: 152 */ 153 if (desc->irq_data.chip->ack) 154 desc->irq_data.chip->ack(irq); 155 if (likely(!(desc->status & IRQ_DISABLED))) { 156 action_ret = handle_IRQ_event(irq, desc->action); 157 if (!noirqdebug) 158 note_interrupt(irq, desc, action_ret); 159 } 160 desc->irq_data.chip->end(irq); 161 return 1; 162 } 163 164 raw_spin_lock(&desc->lock); 165 if (desc->irq_data.chip->ack) 166 desc->irq_data.chip->ack(irq); 167 /* 168 * REPLAY is when Linux resends an IRQ that was dropped earlier 169 * WAITING is used by probe to mark irqs that are being tested 170 */ 171 status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING); 172 status |= IRQ_PENDING; /* we _want_ to handle it */ 173 174 /* 175 * If the IRQ is disabled for whatever reason, we cannot 176 * use the action we have. 177 */ 178 action = NULL; 179 if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) { 180 action = desc->action; 181 status &= ~IRQ_PENDING; /* we commit to handling */ 182 status |= IRQ_INPROGRESS; /* we are handling it */ 183 } 184 desc->status = status; 185 186 /* 187 * If there is no IRQ handler or it was disabled, exit early. 188 * Since we set PENDING, if another processor is handling 189 * a different instance of this same irq, the other processor 190 * will take care of it. 191 */ 192 if (unlikely(!action)) 193 goto out; 194 195 /* 196 * Edge triggered interrupts need to remember 197 * pending events. 198 * This applies to any hw interrupts that allow a second 199 * instance of the same irq to arrive while we are in do_IRQ 200 * or in the handler. But the code here only handles the _second_ 201 * instance of the irq, not the third or fourth. So it is mostly 202 * useful for irq hardware that does not mask cleanly in an 203 * SMP environment. 204 */ 205 for (;;) { 206 irqreturn_t action_ret; 207 208 raw_spin_unlock(&desc->lock); 209 210 action_ret = handle_IRQ_event(irq, action); 211 if (!noirqdebug) 212 note_interrupt(irq, desc, action_ret); 213 214 raw_spin_lock(&desc->lock); 215 if (likely(!(desc->status & IRQ_PENDING))) 216 break; 217 desc->status &= ~IRQ_PENDING; 218 } 219 desc->status &= ~IRQ_INPROGRESS; 220 221 out: 222 /* 223 * The ->end() handler has to deal with interrupts which got 224 * disabled while the handler was running. 225 */ 226 desc->irq_data.chip->end(irq); 227 raw_spin_unlock(&desc->lock); 228 229 return 1; 230 } 231 #endif 232