2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
6 * Code to handle x86 style IRQs plus some generic interrupt stuff.
8 * Copyright (C) 1992 Linus Torvalds
9 * Copyright (C) 1994 - 2000 Ralf Baechle
11 #include <linux/kernel.h>
12 #include <linux/delay.h>
13 #include <linux/init.h>
14 #include <linux/interrupt.h>
15 #include <linux/kernel_stat.h>
16 #include <linux/proc_fs.h>
18 #include <linux/random.h>
19 #include <linux/sched.h>
20 #include <linux/seq_file.h>
21 #include <linux/kallsyms.h>
22 #include <linux/kgdb.h>
23 #include <linux/ftrace.h>
25 #include <linux/atomic.h>
26 #include <asm/uaccess.h>
32 static unsigned long irq_map[NR_IRQS / BITS_PER_LONG];
34 int allocate_irqno(void)
39 irq = find_first_zero_bit(irq_map, NR_IRQS);
44 if (test_and_set_bit(irq, irq_map))
51 * Allocate the 16 legacy interrupts for i8259 devices. This happens early
52 * in the kernel initialization so treating allocation failure as BUG() is
55 void __init alloc_legacy_irqno(void)
59 for (i = 0; i <= 16; i++)
60 BUG_ON(test_and_set_bit(i, irq_map));
63 void free_irqno(unsigned int irq)
65 smp_mb__before_atomic();
66 clear_bit(irq, irq_map);
67 smp_mb__after_atomic();
71 * 'what should we do if we get a hw irq event on an illegal vector'.
72 * each architecture has to answer this themselves.
74 void ack_bad_irq(unsigned int irq)
76 printk("unexpected IRQ # %d\n", irq);
79 atomic_t irq_err_count;
81 int arch_show_interrupts(struct seq_file *p, int prec)
83 seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
87 asmlinkage void spurious_interrupt(void)
89 atomic_inc(&irq_err_count);
92 void __init init_IRQ(void)
101 for (i = 0; i < NR_IRQS; i++)
107 if (!kgdb_early_setup)
108 kgdb_early_setup = 1;
112 #ifdef DEBUG_STACKOVERFLOW
113 static inline void check_stack_overflow(void)
117 __asm__ __volatile__("move %0, $sp" : "=r" (sp));
121 * Check for stack overflow: is there less than STACK_WARN free?
122 * STACK_WARN is defined as 1/8 of THREAD_SIZE by default.
124 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
125 printk("do_IRQ: stack overflow: %ld\n",
126 sp - sizeof(struct thread_info));
131 static inline void check_stack_overflow(void) {}
136 * do_IRQ handles all normal device IRQ's (the special
137 * SMP cross-CPU interrupts have their own specific
140 void __irq_entry do_IRQ(unsigned int irq)
143 check_stack_overflow();
144 generic_handle_irq(irq);