arch/mips/kernel/irq.c

   1 /*
   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
   4  * for more details.
   5  *
   6  * Code to handle x86 style IRQs plus some generic interrupt stuff.
   7  *
   8  * Copyright (C) 1992 Linus Torvalds
   9  * Copyright (C) 1994 - 2000 Ralf Baechle
  10  */
  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>
  17 #include <linux/mm.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>
  24
  25 #include <linux/atomic.h>
  26 #include <asm/uaccess.h>
  27
  28 #ifdef CONFIG_KGDB
  29 int kgdb_early_setup;
  30 #endif
  31
  32 static unsigned long irq_map[NR_IRQS / BITS_PER_LONG];
  33
  34 int allocate_irqno(void)
  35 {
  36         int irq;
  37
  38 again:
  39         irq = find_first_zero_bit(irq_map, NR_IRQS);
  40
  41         if (irq >= NR_IRQS)
  42                 return -ENOSPC;
  43
  44         if (test_and_set_bit(irq, irq_map))
  45                 goto again;
  46
  47         return irq;
  48 }
  49
  50 /*
  51  * Allocate the 16 legacy interrupts for i8259 devices.  This happens early
  52  * in the kernel initialization so treating allocation failure as BUG() is
  53  * ok.
  54  */
  55 void __init alloc_legacy_irqno(void)
  56 {
  57         int i;
  58
  59         for (i = 0; i <= 16; i++)
  60                 BUG_ON(test_and_set_bit(i, irq_map));
  61 }
  62
  63 void free_irqno(unsigned int irq)
  64 {
  65         smp_mb__before_atomic();
  66         clear_bit(irq, irq_map);
  67         smp_mb__after_atomic();
  68 }
  69
  70 /*
  71  * 'what should we do if we get a hw irq event on an illegal vector'.
  72  * each architecture has to answer this themselves.
  73  */
  74 void ack_bad_irq(unsigned int irq)
  75 {
  76         printk("unexpected IRQ # %d\n", irq);
  77 }
  78
  79 atomic_t irq_err_count;
  80
  81 int arch_show_interrupts(struct seq_file *p, int prec)
  82 {
  83         seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
  84         return 0;
  85 }
  86
  87 asmlinkage void spurious_interrupt(void)
  88 {
  89         atomic_inc(&irq_err_count);
  90 }
  91
  92 void __init init_IRQ(void)
  93 {
  94         int i;
  95
  96 #ifdef CONFIG_KGDB
  97         if (kgdb_early_setup)
  98                 return;
  99 #endif
 100
 101         for (i = 0; i < NR_IRQS; i++)
 102                 irq_set_noprobe(i);
 103
 104         arch_init_irq();
 105
 106 #ifdef CONFIG_KGDB
 107         if (!kgdb_early_setup)
 108                 kgdb_early_setup = 1;
 109 #endif
 110 }
 111
 112 #ifdef DEBUG_STACKOVERFLOW
 113 static inline void check_stack_overflow(void)
 114 {
 115         unsigned long sp;
 116
 117         __asm__ __volatile__("move %0, $sp" : "=r" (sp));
 118         sp &= THREAD_MASK;
 119
 120         /*
 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.
 123          */
 124         if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
 125                 printk("do_IRQ: stack overflow: %ld\n",
 126                        sp - sizeof(struct thread_info));
 127                 dump_stack();
 128         }
 129 }
 130 #else
 131 static inline void check_stack_overflow(void) {}
 132 #endif
 133
 134
 135 /*
 136  * do_IRQ handles all normal device IRQ's (the special
 137  * SMP cross-CPU interrupts have their own specific
 138  * handlers).
 139  */
 140 void __irq_entry do_IRQ(unsigned int irq)
 141 {
 142         irq_enter();
 143         check_stack_overflow();
 144         generic_handle_irq(irq);
 145         irq_exit();
 146 }
 147