2 * linux/arch/arm/kernel/irq.c
4 * Copyright (C) 1992 Linus Torvalds
5 * Modifications for ARM processor Copyright (C) 1995-2000 Russell King.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This file contains the code used by various IRQ handling routines:
12 * asking for different IRQ's should be done through these routines
13 * instead of just grabbing them. Thus setups with different IRQ numbers
14 * shouldn't result in any weird surprises, and installing new handlers
17 * IRQ's are in fact implemented a bit like signal handlers for the kernel.
18 * Naturally it's not a 1:1 relation, but there are similarities.
20 #include <linux/config.h>
21 #include <linux/kernel_stat.h>
22 #include <linux/module.h>
23 #include <linux/signal.h>
24 #include <linux/ioport.h>
25 #include <linux/interrupt.h>
26 #include <linux/ptrace.h>
27 #include <linux/slab.h>
28 #include <linux/random.h>
29 #include <linux/smp.h>
30 #include <linux/init.h>
31 #include <linux/seq_file.h>
32 #include <linux/errno.h>
33 #include <linux/list.h>
34 #include <linux/kallsyms.h>
35 #include <linux/proc_fs.h>
38 #include <asm/system.h>
39 #include <asm/mach/irq.h>
42 * Maximum IRQ count. Currently, this is arbitary. However, it should
43 * not be set too low to prevent false triggering. Conversely, if it
44 * is set too high, then you could miss a stuck IRQ.
46 * Maybe we ought to set a timer and re-enable the IRQ at a later time?
48 #define MAX_IRQ_CNT 100000
50 static int noirqdebug;
51 static volatile unsigned long irq_err_count;
52 static DEFINE_SPINLOCK(irq_controller_lock);
53 static LIST_HEAD(irq_pending);
55 struct irqdesc irq_desc[NR_IRQS];
56 void (*init_arch_irq)(void) __initdata = NULL;
59 * No architecture-specific irq_finish function defined in arm/arch/irqs.h.
62 #define irq_finish(irq) do { } while (0)
66 * Dummy mask/unmask handler
68 void dummy_mask_unmask_irq(unsigned int irq)
72 irqreturn_t no_action(int irq, void *dev_id, struct pt_regs *regs)
77 void do_bad_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
80 printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
83 static struct irqchip bad_chip = {
84 .ack = dummy_mask_unmask_irq,
85 .mask = dummy_mask_unmask_irq,
86 .unmask = dummy_mask_unmask_irq,
89 static struct irqdesc bad_irq_desc = {
92 .pend = LIST_HEAD_INIT(bad_irq_desc.pend),
97 void synchronize_irq(unsigned int irq)
99 struct irqdesc *desc = irq_desc + irq;
101 while (desc->running)
104 EXPORT_SYMBOL(synchronize_irq);
106 #define smp_set_running(desc) do { desc->running = 1; } while (0)
107 #define smp_clear_running(desc) do { desc->running = 0; } while (0)
109 #define smp_set_running(desc) do { } while (0)
110 #define smp_clear_running(desc) do { } while (0)
114 * disable_irq_nosync - disable an irq without waiting
115 * @irq: Interrupt to disable
117 * Disable the selected interrupt line. Enables and disables
118 * are nested. We do this lazily.
120 * This function may be called from IRQ context.
122 void disable_irq_nosync(unsigned int irq)
124 struct irqdesc *desc = irq_desc + irq;
127 spin_lock_irqsave(&irq_controller_lock, flags);
128 desc->disable_depth++;
129 list_del_init(&desc->pend);
130 spin_unlock_irqrestore(&irq_controller_lock, flags);
132 EXPORT_SYMBOL(disable_irq_nosync);
135 * disable_irq - disable an irq and wait for completion
136 * @irq: Interrupt to disable
138 * Disable the selected interrupt line. Enables and disables
139 * are nested. This functions waits for any pending IRQ
140 * handlers for this interrupt to complete before returning.
141 * If you use this function while holding a resource the IRQ
142 * handler may need you will deadlock.
144 * This function may be called - with care - from IRQ context.
146 void disable_irq(unsigned int irq)
148 struct irqdesc *desc = irq_desc + irq;
150 disable_irq_nosync(irq);
152 synchronize_irq(irq);
154 EXPORT_SYMBOL(disable_irq);
157 * enable_irq - enable interrupt handling on an irq
158 * @irq: Interrupt to enable
160 * Re-enables the processing of interrupts on this IRQ line.
161 * Note that this may call the interrupt handler, so you may
162 * get unexpected results if you hold IRQs disabled.
164 * This function may be called from IRQ context.
166 void enable_irq(unsigned int irq)
168 struct irqdesc *desc = irq_desc + irq;
171 spin_lock_irqsave(&irq_controller_lock, flags);
172 if (unlikely(!desc->disable_depth)) {
173 printk("enable_irq(%u) unbalanced from %p\n", irq,
174 __builtin_return_address(0));
175 } else if (!--desc->disable_depth) {
177 desc->chip->unmask(irq);
180 * If the interrupt is waiting to be processed,
181 * try to re-run it. We can't directly run it
182 * from here since the caller might be in an
183 * interrupt-protected region.
185 if (desc->pending && list_empty(&desc->pend)) {
187 if (!desc->chip->retrigger ||
188 desc->chip->retrigger(irq))
189 list_add(&desc->pend, &irq_pending);
192 spin_unlock_irqrestore(&irq_controller_lock, flags);
194 EXPORT_SYMBOL(enable_irq);
197 * Enable wake on selected irq
199 void enable_irq_wake(unsigned int irq)
201 struct irqdesc *desc = irq_desc + irq;
204 spin_lock_irqsave(&irq_controller_lock, flags);
205 if (desc->chip->wake)
206 desc->chip->wake(irq, 1);
207 spin_unlock_irqrestore(&irq_controller_lock, flags);
209 EXPORT_SYMBOL(enable_irq_wake);
211 void disable_irq_wake(unsigned int irq)
213 struct irqdesc *desc = irq_desc + irq;
216 spin_lock_irqsave(&irq_controller_lock, flags);
217 if (desc->chip->wake)
218 desc->chip->wake(irq, 0);
219 spin_unlock_irqrestore(&irq_controller_lock, flags);
221 EXPORT_SYMBOL(disable_irq_wake);
223 int show_interrupts(struct seq_file *p, void *v)
225 int i = *(loff_t *) v, cpu;
226 struct irqaction * action;
233 for_each_present_cpu(cpu) {
234 sprintf(cpuname, "CPU%d", cpu);
235 seq_printf(p, " %10s", cpuname);
241 spin_lock_irqsave(&irq_controller_lock, flags);
242 action = irq_desc[i].action;
246 seq_printf(p, "%3d: ", i);
247 for_each_present_cpu(cpu)
248 seq_printf(p, "%10u ", kstat_cpu(cpu).irqs[i]);
249 seq_printf(p, " %s", action->name);
250 for (action = action->next; action; action = action->next)
251 seq_printf(p, ", %s", action->name);
255 spin_unlock_irqrestore(&irq_controller_lock, flags);
256 } else if (i == NR_IRQS) {
257 #ifdef CONFIG_ARCH_ACORN
263 seq_printf(p, "Err: %10lu\n", irq_err_count);
269 * IRQ lock detection.
271 * Hopefully, this should get us out of a few locked situations.
272 * However, it may take a while for this to happen, since we need
273 * a large number if IRQs to appear in the same jiffie with the
274 * same instruction pointer (or within 2 instructions).
276 static int check_irq_lock(struct irqdesc *desc, int irq, struct pt_regs *regs)
278 unsigned long instr_ptr = instruction_pointer(regs);
280 if (desc->lck_jif == jiffies &&
281 desc->lck_pc >= instr_ptr && desc->lck_pc < instr_ptr + 8) {
284 if (desc->lck_cnt > MAX_IRQ_CNT) {
285 printk(KERN_ERR "IRQ LOCK: IRQ%d is locking the system, disabled\n", irq);
290 desc->lck_pc = instruction_pointer(regs);
291 desc->lck_jif = jiffies;
297 report_bad_irq(unsigned int irq, struct pt_regs *regs, struct irqdesc *desc, int ret)
299 static int count = 100;
300 struct irqaction *action;
302 if (!count || noirqdebug)
307 if (ret != IRQ_HANDLED && ret != IRQ_NONE) {
308 printk("irq%u: bogus retval mask %x\n", irq, ret);
310 printk("irq%u: nobody cared\n", irq);
314 printk(KERN_ERR "handlers:");
315 action = desc->action;
317 printk("\n" KERN_ERR "[<%p>]", action->handler);
318 print_symbol(" (%s)", (unsigned long)action->handler);
319 action = action->next;
325 __do_irq(unsigned int irq, struct irqaction *action, struct pt_regs *regs)
330 spin_unlock(&irq_controller_lock);
332 if (!(action->flags & SA_INTERRUPT))
337 ret = action->handler(irq, action->dev_id, regs);
338 if (ret == IRQ_HANDLED)
339 status |= action->flags;
341 action = action->next;
344 if (status & SA_SAMPLE_RANDOM)
345 add_interrupt_randomness(irq);
347 spin_lock_irq(&irq_controller_lock);
353 * This is for software-decoded IRQs. The caller is expected to
354 * handle the ack, clear, mask and unmask issues.
357 do_simple_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
359 struct irqaction *action;
360 const unsigned int cpu = smp_processor_id();
364 kstat_cpu(cpu).irqs[irq]++;
366 smp_set_running(desc);
368 action = desc->action;
370 int ret = __do_irq(irq, action, regs);
371 if (ret != IRQ_HANDLED)
372 report_bad_irq(irq, regs, desc, ret);
375 smp_clear_running(desc);
379 * Most edge-triggered IRQ implementations seem to take a broken
380 * approach to this. Hence the complexity.
383 do_edge_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
385 const unsigned int cpu = smp_processor_id();
390 * If we're currently running this IRQ, or its disabled,
391 * we shouldn't process the IRQ. Instead, turn on the
394 if (unlikely(desc->running || desc->disable_depth))
398 * Acknowledge and clear the IRQ, but don't mask it.
400 desc->chip->ack(irq);
403 * Mark the IRQ currently in progress.
407 kstat_cpu(cpu).irqs[irq]++;
410 struct irqaction *action;
412 action = desc->action;
416 if (desc->pending && !desc->disable_depth) {
418 desc->chip->unmask(irq);
421 __do_irq(irq, action, regs);
422 } while (desc->pending && !desc->disable_depth);
427 * If we were disabled or freed, shut down the handler.
429 if (likely(desc->action && !check_irq_lock(desc, irq, regs)))
434 * We got another IRQ while this one was masked or
435 * currently running. Delay it.
438 desc->chip->mask(irq);
439 desc->chip->ack(irq);
443 * Level-based IRQ handler. Nice and simple.
446 do_level_IRQ(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
448 struct irqaction *action;
449 const unsigned int cpu = smp_processor_id();
454 * Acknowledge, clear _AND_ disable the interrupt.
456 desc->chip->ack(irq);
458 if (likely(!desc->disable_depth)) {
459 kstat_cpu(cpu).irqs[irq]++;
461 smp_set_running(desc);
464 * Return with this interrupt masked if no action
466 action = desc->action;
468 int ret = __do_irq(irq, desc->action, regs);
470 if (ret != IRQ_HANDLED)
471 report_bad_irq(irq, regs, desc, ret);
473 if (likely(!desc->disable_depth &&
474 !check_irq_lock(desc, irq, regs)))
475 desc->chip->unmask(irq);
478 smp_clear_running(desc);
482 static void do_pending_irqs(struct pt_regs *regs)
484 struct list_head head, *l, *n;
487 struct irqdesc *desc;
490 * First, take the pending interrupts off the list.
491 * The act of calling the handlers may add some IRQs
492 * back onto the list.
495 INIT_LIST_HEAD(&irq_pending);
496 head.next->prev = &head;
497 head.prev->next = &head;
500 * Now run each entry. We must delete it from our
501 * list before calling the handler.
503 list_for_each_safe(l, n, &head) {
504 desc = list_entry(l, struct irqdesc, pend);
505 list_del_init(&desc->pend);
506 desc->handle(desc - irq_desc, desc, regs);
510 * The list must be empty.
512 BUG_ON(!list_empty(&head));
513 } while (!list_empty(&irq_pending));
517 * do_IRQ handles all hardware IRQ's. Decoded IRQs should not
518 * come via this function. Instead, they should provide their
521 asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
523 struct irqdesc *desc = irq_desc + irq;
526 * Some hardware gives randomly wrong interrupts. Rather
527 * than crashing, do something sensible.
530 desc = &bad_irq_desc;
533 spin_lock(&irq_controller_lock);
534 desc->handle(irq, desc, regs);
537 * Now re-run any pending interrupts.
539 if (!list_empty(&irq_pending))
540 do_pending_irqs(regs);
544 spin_unlock(&irq_controller_lock);
548 void __set_irq_handler(unsigned int irq, irq_handler_t handle, int is_chained)
550 struct irqdesc *desc;
553 if (irq >= NR_IRQS) {
554 printk(KERN_ERR "Trying to install handler for IRQ%d\n", irq);
561 desc = irq_desc + irq;
563 if (is_chained && desc->chip == &bad_chip)
564 printk(KERN_WARNING "Trying to install chained handler for IRQ%d\n", irq);
566 spin_lock_irqsave(&irq_controller_lock, flags);
567 if (handle == do_bad_IRQ) {
568 desc->chip->mask(irq);
569 desc->chip->ack(irq);
570 desc->disable_depth = 1;
572 desc->handle = handle;
573 if (handle != do_bad_IRQ && is_chained) {
576 desc->disable_depth = 0;
577 desc->chip->unmask(irq);
579 spin_unlock_irqrestore(&irq_controller_lock, flags);
582 void set_irq_chip(unsigned int irq, struct irqchip *chip)
584 struct irqdesc *desc;
587 if (irq >= NR_IRQS) {
588 printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
595 desc = irq_desc + irq;
596 spin_lock_irqsave(&irq_controller_lock, flags);
598 spin_unlock_irqrestore(&irq_controller_lock, flags);
601 int set_irq_type(unsigned int irq, unsigned int type)
603 struct irqdesc *desc;
607 if (irq >= NR_IRQS) {
608 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
612 desc = irq_desc + irq;
613 if (desc->chip->type) {
614 spin_lock_irqsave(&irq_controller_lock, flags);
615 ret = desc->chip->type(irq, type);
616 spin_unlock_irqrestore(&irq_controller_lock, flags);
621 EXPORT_SYMBOL(set_irq_type);
623 void set_irq_flags(unsigned int irq, unsigned int iflags)
625 struct irqdesc *desc;
628 if (irq >= NR_IRQS) {
629 printk(KERN_ERR "Trying to set irq flags for IRQ%d\n", irq);
633 desc = irq_desc + irq;
634 spin_lock_irqsave(&irq_controller_lock, flags);
635 desc->valid = (iflags & IRQF_VALID) != 0;
636 desc->probe_ok = (iflags & IRQF_PROBE) != 0;
637 desc->noautoenable = (iflags & IRQF_NOAUTOEN) != 0;
638 spin_unlock_irqrestore(&irq_controller_lock, flags);
641 int setup_irq(unsigned int irq, struct irqaction *new)
644 struct irqaction *old, **p;
646 struct irqdesc *desc;
649 * Some drivers like serial.c use request_irq() heavily,
650 * so we have to be careful not to interfere with a
653 if (new->flags & SA_SAMPLE_RANDOM) {
655 * This function might sleep, we want to call it first,
656 * outside of the atomic block.
657 * Yes, this might clear the entropy pool if the wrong
658 * driver is attempted to be loaded, without actually
659 * installing a new handler, but is this really a problem,
660 * only the sysadmin is able to do this.
662 rand_initialize_irq(irq);
666 * The following block of code has to be executed atomically
668 desc = irq_desc + irq;
669 spin_lock_irqsave(&irq_controller_lock, flags);
671 if ((old = *p) != NULL) {
672 /* Can't share interrupts unless both agree to */
673 if (!(old->flags & new->flags & SA_SHIRQ)) {
674 spin_unlock_irqrestore(&irq_controller_lock, flags);
678 /* add new interrupt at end of irq queue */
692 desc->disable_depth = 1;
693 if (!desc->noautoenable) {
694 desc->disable_depth = 0;
695 desc->chip->unmask(irq);
699 spin_unlock_irqrestore(&irq_controller_lock, flags);
704 * request_irq - allocate an interrupt line
705 * @irq: Interrupt line to allocate
706 * @handler: Function to be called when the IRQ occurs
707 * @irqflags: Interrupt type flags
708 * @devname: An ascii name for the claiming device
709 * @dev_id: A cookie passed back to the handler function
711 * This call allocates interrupt resources and enables the
712 * interrupt line and IRQ handling. From the point this
713 * call is made your handler function may be invoked. Since
714 * your handler function must clear any interrupt the board
715 * raises, you must take care both to initialise your hardware
716 * and to set up the interrupt handler in the right order.
718 * Dev_id must be globally unique. Normally the address of the
719 * device data structure is used as the cookie. Since the handler
720 * receives this value it makes sense to use it.
722 * If your interrupt is shared you must pass a non NULL dev_id
723 * as this is required when freeing the interrupt.
727 * SA_SHIRQ Interrupt is shared
729 * SA_INTERRUPT Disable local interrupts while processing
731 * SA_SAMPLE_RANDOM The interrupt can be used for entropy
734 int request_irq(unsigned int irq, irqreturn_t (*handler)(int, void *, struct pt_regs *),
735 unsigned long irq_flags, const char * devname, void *dev_id)
737 unsigned long retval;
738 struct irqaction *action;
740 if (irq >= NR_IRQS || !irq_desc[irq].valid || !handler ||
741 (irq_flags & SA_SHIRQ && !dev_id))
744 action = (struct irqaction *)kmalloc(sizeof(struct irqaction), GFP_KERNEL);
748 action->handler = handler;
749 action->flags = irq_flags;
750 cpus_clear(action->mask);
751 action->name = devname;
753 action->dev_id = dev_id;
755 retval = setup_irq(irq, action);
762 EXPORT_SYMBOL(request_irq);
765 * free_irq - free an interrupt
766 * @irq: Interrupt line to free
767 * @dev_id: Device identity to free
769 * Remove an interrupt handler. The handler is removed and if the
770 * interrupt line is no longer in use by any driver it is disabled.
771 * On a shared IRQ the caller must ensure the interrupt is disabled
772 * on the card it drives before calling this function.
774 * This function must not be called from interrupt context.
776 void free_irq(unsigned int irq, void *dev_id)
778 struct irqaction * action, **p;
781 if (irq >= NR_IRQS || !irq_desc[irq].valid) {
782 printk(KERN_ERR "Trying to free IRQ%d\n",irq);
787 spin_lock_irqsave(&irq_controller_lock, flags);
788 for (p = &irq_desc[irq].action; (action = *p) != NULL; p = &action->next) {
789 if (action->dev_id != dev_id)
792 /* Found it - now free it */
796 spin_unlock_irqrestore(&irq_controller_lock, flags);
799 printk(KERN_ERR "Trying to free free IRQ%d\n",irq);
802 synchronize_irq(irq);
807 EXPORT_SYMBOL(free_irq);
809 static DECLARE_MUTEX(probe_sem);
811 /* Start the interrupt probing. Unlike other architectures,
812 * we don't return a mask of interrupts from probe_irq_on,
813 * but return the number of interrupts enabled for the probe.
814 * The interrupts which have been enabled for probing is
815 * instead recorded in the irq_desc structure.
817 unsigned long probe_irq_on(void)
819 unsigned int i, irqs = 0;
825 * first snaffle up any unassigned but
826 * probe-able interrupts
828 spin_lock_irq(&irq_controller_lock);
829 for (i = 0; i < NR_IRQS; i++) {
830 if (!irq_desc[i].probe_ok || irq_desc[i].action)
833 irq_desc[i].probing = 1;
834 irq_desc[i].triggered = 0;
835 if (irq_desc[i].chip->type)
836 irq_desc[i].chip->type(i, IRQT_PROBE);
837 irq_desc[i].chip->unmask(i);
840 spin_unlock_irq(&irq_controller_lock);
843 * wait for spurious interrupts to mask themselves out again
845 for (delay = jiffies + HZ/10; time_before(jiffies, delay); )
846 /* min 100ms delay */;
849 * now filter out any obviously spurious interrupts
851 spin_lock_irq(&irq_controller_lock);
852 for (i = 0; i < NR_IRQS; i++) {
853 if (irq_desc[i].probing && irq_desc[i].triggered) {
854 irq_desc[i].probing = 0;
858 spin_unlock_irq(&irq_controller_lock);
863 EXPORT_SYMBOL(probe_irq_on);
865 unsigned int probe_irq_mask(unsigned long irqs)
867 unsigned int mask = 0, i;
869 spin_lock_irq(&irq_controller_lock);
870 for (i = 0; i < 16 && i < NR_IRQS; i++)
871 if (irq_desc[i].probing && irq_desc[i].triggered)
873 spin_unlock_irq(&irq_controller_lock);
879 EXPORT_SYMBOL(probe_irq_mask);
882 * Possible return values:
883 * >= 0 - interrupt number
884 * -1 - no interrupt/many interrupts
886 int probe_irq_off(unsigned long irqs)
889 int irq_found = NO_IRQ;
892 * look at the interrupts, and find exactly one
893 * that we were probing has been triggered
895 spin_lock_irq(&irq_controller_lock);
896 for (i = 0; i < NR_IRQS; i++) {
897 if (irq_desc[i].probing &&
898 irq_desc[i].triggered) {
899 if (irq_found != NO_IRQ) {
910 spin_unlock_irq(&irq_controller_lock);
917 EXPORT_SYMBOL(probe_irq_off);
920 static void route_irq(struct irqdesc *desc, unsigned int irq, unsigned int cpu)
922 pr_debug("IRQ%u: moving from cpu%u to cpu%u\n", irq, desc->cpu, cpu);
924 spin_lock_irq(&irq_controller_lock);
926 desc->chip->set_cpu(desc, irq, cpu);
927 spin_unlock_irq(&irq_controller_lock);
930 #ifdef CONFIG_PROC_FS
932 irq_affinity_read_proc(char *page, char **start, off_t off, int count,
933 int *eof, void *data)
935 struct irqdesc *desc = irq_desc + ((int)data);
936 int len = cpumask_scnprintf(page, count, desc->affinity);
947 irq_affinity_write_proc(struct file *file, const char __user *buffer,
948 unsigned long count, void *data)
950 unsigned int irq = (unsigned int)data;
951 struct irqdesc *desc = irq_desc + irq;
952 cpumask_t affinity, tmp;
955 if (!desc->chip->set_cpu)
958 ret = cpumask_parse(buffer, count, affinity);
962 cpus_and(tmp, affinity, cpu_online_map);
963 if (cpus_empty(tmp)) {
968 desc->affinity = affinity;
969 route_irq(desc, irq, first_cpu(tmp));
978 void __init init_irq_proc(void)
980 #if defined(CONFIG_SMP) && defined(CONFIG_PROC_FS)
981 struct proc_dir_entry *dir;
984 dir = proc_mkdir("irq", 0);
988 for (irq = 0; irq < NR_IRQS; irq++) {
989 struct proc_dir_entry *entry;
990 struct irqdesc *desc;
993 desc = irq_desc + irq;
994 memset(name, 0, sizeof(name));
995 snprintf(name, sizeof(name) - 1, "%u", irq);
997 desc->procdir = proc_mkdir(name, dir);
1001 entry = create_proc_entry("smp_affinity", 0600, desc->procdir);
1004 entry->data = (void *)irq;
1005 entry->read_proc = irq_affinity_read_proc;
1006 entry->write_proc = irq_affinity_write_proc;
1012 void __init init_IRQ(void)
1014 struct irqdesc *desc;
1015 extern void init_dma(void);
1019 bad_irq_desc.affinity = CPU_MASK_ALL;
1020 bad_irq_desc.cpu = smp_processor_id();
1023 for (irq = 0, desc = irq_desc; irq < NR_IRQS; irq++, desc++) {
1024 *desc = bad_irq_desc;
1025 INIT_LIST_HEAD(&desc->pend);
1032 static int __init noirqdebug_setup(char *str)
1038 __setup("noirqdebug", noirqdebug_setup);