1 /* 2 * linux/kernel/irq/spurious.c 3 * 4 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar 5 * 6 * This file contains spurious interrupt handling. 7 */ 8 9 #include <linux/jiffies.h> 10 #include <linux/irq.h> 11 #include <linux/module.h> 12 #include <linux/kallsyms.h> 13 #include <linux/interrupt.h> 14 #include <linux/moduleparam.h> 15 #include <linux/timer.h> 16 17 #include "internals.h" 18 19 static int irqfixup __read_mostly; 20 21 #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10) 22 static void poll_spurious_irqs(unsigned long dummy); 23 static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0); 24 static int irq_poll_cpu; 25 static atomic_t irq_poll_active; 26 27 /* 28 * We wait here for a poller to finish. 29 * 30 * If the poll runs on this CPU, then we yell loudly and return 31 * false. That will leave the interrupt line disabled in the worst 32 * case, but it should never happen. 33 * 34 * We wait until the poller is done and then recheck disabled and 35 * action (about to be disabled). Only if it's still active, we return 36 * true and let the handler run. 37 */ 38 bool irq_wait_for_poll(struct irq_desc *desc) 39 { 40 if (WARN_ONCE(irq_poll_cpu == smp_processor_id(), 41 "irq poll in progress on cpu %d for irq %d\n", 42 smp_processor_id(), desc->irq_data.irq)) 43 return false; 44 45 #ifdef CONFIG_SMP 46 do { 47 raw_spin_unlock(&desc->lock); 48 while (irqd_irq_inprogress(&desc->irq_data)) 49 cpu_relax(); 50 raw_spin_lock(&desc->lock); 51 } while (irqd_irq_inprogress(&desc->irq_data)); 52 /* Might have been disabled in meantime */ 53 return !irqd_irq_disabled(&desc->irq_data) && desc->action; 54 #else 55 return false; 56 #endif 57 } 58 59 60 /* 61 * Recovery handler for misrouted interrupts. 62 */ 63 static int try_one_irq(int irq, struct irq_desc *desc, bool force) 64 { 65 irqreturn_t ret = IRQ_NONE; 66 struct irqaction *action; 67 68 raw_spin_lock(&desc->lock); 69 70 /* PER_CPU and nested thread interrupts are never polled */ 71 if (irq_settings_is_per_cpu(desc) || irq_settings_is_nested_thread(desc)) 72 goto out; 73 74 /* 75 * Do not poll disabled interrupts unless the spurious 76 * disabled poller asks explicitely. 77 */ 78 if (irqd_irq_disabled(&desc->irq_data) && !force) 79 goto out; 80 81 /* 82 * All handlers must agree on IRQF_SHARED, so we test just the 83 * first. 84 */ 85 action = desc->action; 86 if (!action || !(action->flags & IRQF_SHARED) || 87 (action->flags & __IRQF_TIMER)) 88 goto out; 89 90 /* Already running on another processor */ 91 if (irqd_irq_inprogress(&desc->irq_data)) { 92 /* 93 * Already running: If it is shared get the other 94 * CPU to go looking for our mystery interrupt too 95 */ 96 desc->istate |= IRQS_PENDING; 97 goto out; 98 } 99 100 /* Mark it poll in progress */ 101 desc->istate |= IRQS_POLL_INPROGRESS; 102 do { 103 if (handle_irq_event(desc) == IRQ_HANDLED) 104 ret = IRQ_HANDLED; 105 /* Make sure that there is still a valid action */ 106 action = desc->action; 107 } while ((desc->istate & IRQS_PENDING) && action); 108 desc->istate &= ~IRQS_POLL_INPROGRESS; 109 out: 110 raw_spin_unlock(&desc->lock); 111 return ret == IRQ_HANDLED; 112 } 113 114 static int misrouted_irq(int irq) 115 { 116 struct irq_desc *desc; 117 int i, ok = 0; 118 119 if (atomic_inc_return(&irq_poll_active) != 1) 120 goto out; 121 122 irq_poll_cpu = smp_processor_id(); 123 124 for_each_irq_desc(i, desc) { 125 if (!i) 126 continue; 127 128 if (i == irq) /* Already tried */ 129 continue; 130 131 if (try_one_irq(i, desc, false)) 132 ok = 1; 133 } 134 out: 135 atomic_dec(&irq_poll_active); 136 /* So the caller can adjust the irq error counts */ 137 return ok; 138 } 139 140 static void poll_spurious_irqs(unsigned long dummy) 141 { 142 struct irq_desc *desc; 143 int i; 144 145 if (atomic_inc_return(&irq_poll_active) != 1) 146 goto out; 147 irq_poll_cpu = smp_processor_id(); 148 149 for_each_irq_desc(i, desc) { 150 unsigned int state; 151 152 if (!i) 153 continue; 154 155 /* Racy but it doesn't matter */ 156 state = desc->istate; 157 barrier(); 158 if (!(state & IRQS_SPURIOUS_DISABLED)) 159 continue; 160 161 local_irq_disable(); 162 try_one_irq(i, desc, true); 163 local_irq_enable(); 164 } 165 out: 166 atomic_dec(&irq_poll_active); 167 mod_timer(&poll_spurious_irq_timer, 168 jiffies + POLL_SPURIOUS_IRQ_INTERVAL); 169 } 170 171 static inline int bad_action_ret(irqreturn_t action_ret) 172 { 173 if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD))) 174 return 0; 175 return 1; 176 } 177 178 /* 179 * If 99,900 of the previous 100,000 interrupts have not been handled 180 * then assume that the IRQ is stuck in some manner. Drop a diagnostic 181 * and try to turn the IRQ off. 182 * 183 * (The other 100-of-100,000 interrupts may have been a correctly 184 * functioning device sharing an IRQ with the failing one) 185 */ 186 static void 187 __report_bad_irq(unsigned int irq, struct irq_desc *desc, 188 irqreturn_t action_ret) 189 { 190 struct irqaction *action; 191 unsigned long flags; 192 193 if (bad_action_ret(action_ret)) { 194 printk(KERN_ERR "irq event %d: bogus return value %x\n", 195 irq, action_ret); 196 } else { 197 printk(KERN_ERR "irq %d: nobody cared (try booting with " 198 "the \"irqpoll\" option)\n", irq); 199 } 200 dump_stack(); 201 printk(KERN_ERR "handlers:\n"); 202 203 /* 204 * We need to take desc->lock here. note_interrupt() is called 205 * w/o desc->lock held, but IRQ_PROGRESS set. We might race 206 * with something else removing an action. It's ok to take 207 * desc->lock here. See synchronize_irq(). 208 */ 209 raw_spin_lock_irqsave(&desc->lock, flags); 210 action = desc->action; 211 while (action) { 212 printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler); 213 if (action->thread_fn) 214 printk(KERN_CONT " threaded [<%p>] %pf", 215 action->thread_fn, action->thread_fn); 216 printk(KERN_CONT "\n"); 217 action = action->next; 218 } 219 raw_spin_unlock_irqrestore(&desc->lock, flags); 220 } 221 222 static void 223 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret) 224 { 225 static int count = 100; 226 227 if (count > 0) { 228 count--; 229 __report_bad_irq(irq, desc, action_ret); 230 } 231 } 232 233 static inline int 234 try_misrouted_irq(unsigned int irq, struct irq_desc *desc, 235 irqreturn_t action_ret) 236 { 237 struct irqaction *action; 238 239 if (!irqfixup) 240 return 0; 241 242 /* We didn't actually handle the IRQ - see if it was misrouted? */ 243 if (action_ret == IRQ_NONE) 244 return 1; 245 246 /* 247 * But for 'irqfixup == 2' we also do it for handled interrupts if 248 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the 249 * traditional PC timer interrupt.. Legacy) 250 */ 251 if (irqfixup < 2) 252 return 0; 253 254 if (!irq) 255 return 1; 256 257 /* 258 * Since we don't get the descriptor lock, "action" can 259 * change under us. We don't really care, but we don't 260 * want to follow a NULL pointer. So tell the compiler to 261 * just load it once by using a barrier. 262 */ 263 action = desc->action; 264 barrier(); 265 return action && (action->flags & IRQF_IRQPOLL); 266 } 267 268 void note_interrupt(unsigned int irq, struct irq_desc *desc, 269 irqreturn_t action_ret) 270 { 271 if (desc->istate & IRQS_POLL_INPROGRESS) 272 return; 273 274 /* we get here again via the threaded handler */ 275 if (action_ret == IRQ_WAKE_THREAD) 276 return; 277 278 if (bad_action_ret(action_ret)) { 279 report_bad_irq(irq, desc, action_ret); 280 return; 281 } 282 283 if (unlikely(action_ret == IRQ_NONE)) { 284 /* 285 * If we are seeing only the odd spurious IRQ caused by 286 * bus asynchronicity then don't eventually trigger an error, 287 * otherwise the counter becomes a doomsday timer for otherwise 288 * working systems 289 */ 290 if (time_after(jiffies, desc->last_unhandled + HZ/10)) 291 desc->irqs_unhandled = 1; 292 else 293 desc->irqs_unhandled++; 294 desc->last_unhandled = jiffies; 295 } 296 297 if (unlikely(try_misrouted_irq(irq, desc, action_ret))) { 298 int ok = misrouted_irq(irq); 299 if (action_ret == IRQ_NONE) 300 desc->irqs_unhandled -= ok; 301 } 302 303 desc->irq_count++; 304 if (likely(desc->irq_count < 100000)) 305 return; 306 307 desc->irq_count = 0; 308 if (unlikely(desc->irqs_unhandled > 99900)) { 309 /* 310 * The interrupt is stuck 311 */ 312 __report_bad_irq(irq, desc, action_ret); 313 /* 314 * Now kill the IRQ 315 */ 316 printk(KERN_EMERG "Disabling IRQ #%d\n", irq); 317 desc->istate |= IRQS_SPURIOUS_DISABLED; 318 desc->depth++; 319 irq_disable(desc); 320 321 mod_timer(&poll_spurious_irq_timer, 322 jiffies + POLL_SPURIOUS_IRQ_INTERVAL); 323 } 324 desc->irqs_unhandled = 0; 325 } 326 327 bool noirqdebug __read_mostly; 328 329 int noirqdebug_setup(char *str) 330 { 331 noirqdebug = 1; 332 printk(KERN_INFO "IRQ lockup detection disabled\n"); 333 334 return 1; 335 } 336 337 __setup("noirqdebug", noirqdebug_setup); 338 module_param(noirqdebug, bool, 0644); 339 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true"); 340 341 static int __init irqfixup_setup(char *str) 342 { 343 irqfixup = 1; 344 printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n"); 345 printk(KERN_WARNING "This may impact system performance.\n"); 346 347 return 1; 348 } 349 350 __setup("irqfixup", irqfixup_setup); 351 module_param(irqfixup, int, 0644); 352 353 static int __init irqpoll_setup(char *str) 354 { 355 irqfixup = 2; 356 printk(KERN_WARNING "Misrouted IRQ fixup and polling support " 357 "enabled\n"); 358 printk(KERN_WARNING "This may significantly impact system " 359 "performance\n"); 360 return 1; 361 } 362 363 __setup("irqpoll", irqpoll_setup); 364