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 (desc->istate & IRQS_INPROGRESS) 49 cpu_relax(); 50 raw_spin_lock(&desc->lock); 51 } while (desc->istate & IRQS_INPROGRESS); 52 /* Might have been disabled in meantime */ 53 return !(desc->istate & IRQS_DISABLED) && 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 ((desc->istate & IRQS_DISABLED) && !force) 79 goto out; 80 81 /* 82 * All handlers must agree on IRQF_SHARED, so we test just the 83 * first. Check for action->next as well. 84 */ 85 action = desc->action; 86 if (!action || !(action->flags & IRQF_SHARED) || 87 (action->flags & __IRQF_TIMER) || !action->next) 88 goto out; 89 90 /* Already running on another processor */ 91 if (desc->istate & IRQS_INPROGRESS) { 92 /* 93 * Already running: If it is shared get the other 94 * CPU to go looking for our mystery interrupt too 95 */ 96 irq_compat_set_pending(desc); 97 desc->istate |= IRQS_PENDING; 98 goto out; 99 } 100 101 /* Mark it poll in progress */ 102 desc->istate |= IRQS_POLL_INPROGRESS; 103 do { 104 if (handle_irq_event(desc) == IRQ_HANDLED) 105 ret = IRQ_HANDLED; 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 /* 172 * If 99,900 of the previous 100,000 interrupts have not been handled 173 * then assume that the IRQ is stuck in some manner. Drop a diagnostic 174 * and try to turn the IRQ off. 175 * 176 * (The other 100-of-100,000 interrupts may have been a correctly 177 * functioning device sharing an IRQ with the failing one) 178 */ 179 static void 180 __report_bad_irq(unsigned int irq, struct irq_desc *desc, 181 irqreturn_t action_ret) 182 { 183 struct irqaction *action; 184 unsigned long flags; 185 186 if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) { 187 printk(KERN_ERR "irq event %d: bogus return value %x\n", 188 irq, action_ret); 189 } else { 190 printk(KERN_ERR "irq %d: nobody cared (try booting with " 191 "the \"irqpoll\" option)\n", irq); 192 } 193 dump_stack(); 194 printk(KERN_ERR "handlers:\n"); 195 196 /* 197 * We need to take desc->lock here. note_interrupt() is called 198 * w/o desc->lock held, but IRQ_PROGRESS set. We might race 199 * with something else removing an action. It's ok to take 200 * desc->lock here. See synchronize_irq(). 201 */ 202 raw_spin_lock_irqsave(&desc->lock, flags); 203 action = desc->action; 204 while (action) { 205 printk(KERN_ERR "[<%p>]", action->handler); 206 print_symbol(" (%s)", 207 (unsigned long)action->handler); 208 printk("\n"); 209 action = action->next; 210 } 211 raw_spin_unlock_irqrestore(&desc->lock, flags); 212 } 213 214 static void 215 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret) 216 { 217 static int count = 100; 218 219 if (count > 0) { 220 count--; 221 __report_bad_irq(irq, desc, action_ret); 222 } 223 } 224 225 static inline int 226 try_misrouted_irq(unsigned int irq, struct irq_desc *desc, 227 irqreturn_t action_ret) 228 { 229 struct irqaction *action; 230 231 if (!irqfixup) 232 return 0; 233 234 /* We didn't actually handle the IRQ - see if it was misrouted? */ 235 if (action_ret == IRQ_NONE) 236 return 1; 237 238 /* 239 * But for 'irqfixup == 2' we also do it for handled interrupts if 240 * they are marked as IRQF_IRQPOLL (or for irq zero, which is the 241 * traditional PC timer interrupt.. Legacy) 242 */ 243 if (irqfixup < 2) 244 return 0; 245 246 if (!irq) 247 return 1; 248 249 /* 250 * Since we don't get the descriptor lock, "action" can 251 * change under us. We don't really care, but we don't 252 * want to follow a NULL pointer. So tell the compiler to 253 * just load it once by using a barrier. 254 */ 255 action = desc->action; 256 barrier(); 257 return action && (action->flags & IRQF_IRQPOLL); 258 } 259 260 void note_interrupt(unsigned int irq, struct irq_desc *desc, 261 irqreturn_t action_ret) 262 { 263 if (desc->istate & IRQS_POLL_INPROGRESS) 264 return; 265 266 if (unlikely(action_ret != IRQ_HANDLED)) { 267 /* 268 * If we are seeing only the odd spurious IRQ caused by 269 * bus asynchronicity then don't eventually trigger an error, 270 * otherwise the counter becomes a doomsday timer for otherwise 271 * working systems 272 */ 273 if (time_after(jiffies, desc->last_unhandled + HZ/10)) 274 desc->irqs_unhandled = 1; 275 else 276 desc->irqs_unhandled++; 277 desc->last_unhandled = jiffies; 278 if (unlikely(action_ret != IRQ_NONE)) 279 report_bad_irq(irq, desc, action_ret); 280 } 281 282 if (unlikely(try_misrouted_irq(irq, desc, action_ret))) { 283 int ok = misrouted_irq(irq); 284 if (action_ret == IRQ_NONE) 285 desc->irqs_unhandled -= ok; 286 } 287 288 desc->irq_count++; 289 if (likely(desc->irq_count < 100000)) 290 return; 291 292 desc->irq_count = 0; 293 if (unlikely(desc->irqs_unhandled > 99900)) { 294 /* 295 * The interrupt is stuck 296 */ 297 __report_bad_irq(irq, desc, action_ret); 298 /* 299 * Now kill the IRQ 300 */ 301 printk(KERN_EMERG "Disabling IRQ #%d\n", irq); 302 desc->istate |= IRQS_SPURIOUS_DISABLED; 303 desc->depth++; 304 irq_disable(desc); 305 306 mod_timer(&poll_spurious_irq_timer, 307 jiffies + POLL_SPURIOUS_IRQ_INTERVAL); 308 } 309 desc->irqs_unhandled = 0; 310 } 311 312 int noirqdebug __read_mostly; 313 314 int noirqdebug_setup(char *str) 315 { 316 noirqdebug = 1; 317 printk(KERN_INFO "IRQ lockup detection disabled\n"); 318 319 return 1; 320 } 321 322 __setup("noirqdebug", noirqdebug_setup); 323 module_param(noirqdebug, bool, 0644); 324 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true"); 325 326 static int __init irqfixup_setup(char *str) 327 { 328 irqfixup = 1; 329 printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n"); 330 printk(KERN_WARNING "This may impact system performance.\n"); 331 332 return 1; 333 } 334 335 __setup("irqfixup", irqfixup_setup); 336 module_param(irqfixup, int, 0644); 337 338 static int __init irqpoll_setup(char *str) 339 { 340 irqfixup = 2; 341 printk(KERN_WARNING "Misrouted IRQ fixup and polling support " 342 "enabled\n"); 343 printk(KERN_WARNING "This may significantly impact system " 344 "performance\n"); 345 return 1; 346 } 347 348 __setup("irqpoll", irqpoll_setup); 349