| 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/module.h> |
| 15 | #include <linux/random.h> |
| 16 | #include <linux/interrupt.h> |
| 17 | #include <linux/kernel_stat.h> |
| 18 | |
| 19 | #include "internals.h" |
| 20 | |
| 21 | /** |
| 22 | * handle_bad_irq - handle spurious and unhandled irqs |
| 23 | * @irq: the interrupt number |
| 24 | * @desc: description of the interrupt |
| 25 | * |
| 26 | * Handles spurious and unhandled IRQ's. It also prints a debugmessage. |
| 27 | */ |
| 28 | void fastcall |
| 29 | handle_bad_irq(unsigned int irq, struct irq_desc *desc) |
| 30 | { |
| 31 | print_irq_desc(irq, desc); |
| 32 | kstat_this_cpu.irqs[irq]++; |
| 33 | ack_bad_irq(irq); |
| 34 | } |
| 35 | |
| 36 | /* |
| 37 | * Linux has a controller-independent interrupt architecture. |
| 38 | * Every controller has a 'controller-template', that is used |
| 39 | * by the main code to do the right thing. Each driver-visible |
| 40 | * interrupt source is transparently wired to the appropriate |
| 41 | * controller. Thus drivers need not be aware of the |
| 42 | * interrupt-controller. |
| 43 | * |
| 44 | * The code is designed to be easily extended with new/different |
| 45 | * interrupt controllers, without having to do assembly magic or |
| 46 | * having to touch the generic code. |
| 47 | * |
| 48 | * Controller mappings for all interrupt sources: |
| 49 | */ |
| 50 | struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = { |
| 51 | [0 ... NR_IRQS-1] = { |
| 52 | .status = IRQ_DISABLED, |
| 53 | .chip = &no_irq_chip, |
| 54 | .handle_irq = handle_bad_irq, |
| 55 | .depth = 1, |
| 56 | .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock), |
| 57 | #ifdef CONFIG_SMP |
| 58 | .affinity = CPU_MASK_ALL |
| 59 | #endif |
| 60 | } |
| 61 | }; |
| 62 | |
| 63 | /* |
| 64 | * What should we do if we get a hw irq event on an illegal vector? |
| 65 | * Each architecture has to answer this themself. |
| 66 | */ |
| 67 | static void ack_bad(unsigned int irq) |
| 68 | { |
| 69 | print_irq_desc(irq, irq_desc + irq); |
| 70 | ack_bad_irq(irq); |
| 71 | } |
| 72 | |
| 73 | /* |
| 74 | * NOP functions |
| 75 | */ |
| 76 | static void noop(unsigned int irq) |
| 77 | { |
| 78 | } |
| 79 | |
| 80 | static unsigned int noop_ret(unsigned int irq) |
| 81 | { |
| 82 | return 0; |
| 83 | } |
| 84 | |
| 85 | /* |
| 86 | * Generic no controller implementation |
| 87 | */ |
| 88 | struct irq_chip no_irq_chip = { |
| 89 | .name = "none", |
| 90 | .startup = noop_ret, |
| 91 | .shutdown = noop, |
| 92 | .enable = noop, |
| 93 | .disable = noop, |
| 94 | .ack = ack_bad, |
| 95 | .end = noop, |
| 96 | }; |
| 97 | |
| 98 | /* |
| 99 | * Generic dummy implementation which can be used for |
| 100 | * real dumb interrupt sources |
| 101 | */ |
| 102 | struct irq_chip dummy_irq_chip = { |
| 103 | .name = "dummy", |
| 104 | .startup = noop_ret, |
| 105 | .shutdown = noop, |
| 106 | .enable = noop, |
| 107 | .disable = noop, |
| 108 | .ack = noop, |
| 109 | .mask = noop, |
| 110 | .unmask = noop, |
| 111 | .end = noop, |
| 112 | }; |
| 113 | |
| 114 | /* |
| 115 | * Special, empty irq handler: |
| 116 | */ |
| 117 | irqreturn_t no_action(int cpl, void *dev_id) |
| 118 | { |
| 119 | return IRQ_NONE; |
| 120 | } |
| 121 | |
| 122 | /** |
| 123 | * handle_IRQ_event - irq action chain handler |
| 124 | * @irq: the interrupt number |
| 125 | * @action: the interrupt action chain for this irq |
| 126 | * |
| 127 | * Handles the action chain of an irq event |
| 128 | */ |
| 129 | irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action) |
| 130 | { |
| 131 | irqreturn_t ret, retval = IRQ_NONE; |
| 132 | unsigned int status = 0; |
| 133 | |
| 134 | handle_dynamic_tick(action); |
| 135 | |
| 136 | if (!(action->flags & IRQF_DISABLED)) |
| 137 | local_irq_enable_in_hardirq(); |
| 138 | |
| 139 | do { |
| 140 | ret = action->handler(irq, action->dev_id); |
| 141 | if (ret == IRQ_HANDLED) |
| 142 | status |= action->flags; |
| 143 | retval |= ret; |
| 144 | action = action->next; |
| 145 | } while (action); |
| 146 | |
| 147 | if (status & IRQF_SAMPLE_RANDOM) |
| 148 | add_interrupt_randomness(irq); |
| 149 | local_irq_disable(); |
| 150 | |
| 151 | return retval; |
| 152 | } |
| 153 | |
| 154 | #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ |
| 155 | /** |
| 156 | * __do_IRQ - original all in one highlevel IRQ handler |
| 157 | * @irq: the interrupt number |
| 158 | * |
| 159 | * __do_IRQ handles all normal device IRQ's (the special |
| 160 | * SMP cross-CPU interrupts have their own specific |
| 161 | * handlers). |
| 162 | * |
| 163 | * This is the original x86 implementation which is used for every |
| 164 | * interrupt type. |
| 165 | */ |
| 166 | fastcall unsigned int __do_IRQ(unsigned int irq) |
| 167 | { |
| 168 | struct irq_desc *desc = irq_desc + irq; |
| 169 | struct irqaction *action; |
| 170 | unsigned int status; |
| 171 | |
| 172 | kstat_this_cpu.irqs[irq]++; |
| 173 | if (CHECK_IRQ_PER_CPU(desc->status)) { |
| 174 | irqreturn_t action_ret; |
| 175 | |
| 176 | /* |
| 177 | * No locking required for CPU-local interrupts: |
| 178 | */ |
| 179 | if (desc->chip->ack) |
| 180 | desc->chip->ack(irq); |
| 181 | action_ret = handle_IRQ_event(irq, desc->action); |
| 182 | if (!noirqdebug) |
| 183 | note_interrupt(irq, desc, action_ret); |
| 184 | desc->chip->end(irq); |
| 185 | return 1; |
| 186 | } |
| 187 | |
| 188 | spin_lock(&desc->lock); |
| 189 | if (desc->chip->ack) |
| 190 | desc->chip->ack(irq); |
| 191 | /* |
| 192 | * REPLAY is when Linux resends an IRQ that was dropped earlier |
| 193 | * WAITING is used by probe to mark irqs that are being tested |
| 194 | */ |
| 195 | status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING); |
| 196 | status |= IRQ_PENDING; /* we _want_ to handle it */ |
| 197 | |
| 198 | /* |
| 199 | * If the IRQ is disabled for whatever reason, we cannot |
| 200 | * use the action we have. |
| 201 | */ |
| 202 | action = NULL; |
| 203 | if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) { |
| 204 | action = desc->action; |
| 205 | status &= ~IRQ_PENDING; /* we commit to handling */ |
| 206 | status |= IRQ_INPROGRESS; /* we are handling it */ |
| 207 | } |
| 208 | desc->status = status; |
| 209 | |
| 210 | /* |
| 211 | * If there is no IRQ handler or it was disabled, exit early. |
| 212 | * Since we set PENDING, if another processor is handling |
| 213 | * a different instance of this same irq, the other processor |
| 214 | * will take care of it. |
| 215 | */ |
| 216 | if (unlikely(!action)) |
| 217 | goto out; |
| 218 | |
| 219 | /* |
| 220 | * Edge triggered interrupts need to remember |
| 221 | * pending events. |
| 222 | * This applies to any hw interrupts that allow a second |
| 223 | * instance of the same irq to arrive while we are in do_IRQ |
| 224 | * or in the handler. But the code here only handles the _second_ |
| 225 | * instance of the irq, not the third or fourth. So it is mostly |
| 226 | * useful for irq hardware that does not mask cleanly in an |
| 227 | * SMP environment. |
| 228 | */ |
| 229 | for (;;) { |
| 230 | irqreturn_t action_ret; |
| 231 | |
| 232 | spin_unlock(&desc->lock); |
| 233 | |
| 234 | action_ret = handle_IRQ_event(irq, action); |
| 235 | if (!noirqdebug) |
| 236 | note_interrupt(irq, desc, action_ret); |
| 237 | |
| 238 | spin_lock(&desc->lock); |
| 239 | if (likely(!(desc->status & IRQ_PENDING))) |
| 240 | break; |
| 241 | desc->status &= ~IRQ_PENDING; |
| 242 | } |
| 243 | desc->status &= ~IRQ_INPROGRESS; |
| 244 | |
| 245 | out: |
| 246 | /* |
| 247 | * The ->end() handler has to deal with interrupts which got |
| 248 | * disabled while the handler was running. |
| 249 | */ |
| 250 | desc->chip->end(irq); |
| 251 | spin_unlock(&desc->lock); |
| 252 | |
| 253 | return 1; |
| 254 | } |
| 255 | #endif |
| 256 | |
| 257 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 258 | |
| 259 | /* |
| 260 | * lockdep: we want to handle all irq_desc locks as a single lock-class: |
| 261 | */ |
| 262 | static struct lock_class_key irq_desc_lock_class; |
| 263 | |
| 264 | void early_init_irq_lock_class(void) |
| 265 | { |
| 266 | int i; |
| 267 | |
| 268 | for (i = 0; i < NR_IRQS; i++) |
| 269 | lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class); |
| 270 | } |
| 271 | |
| 272 | #endif |