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/module.h>
17 #include <linux/proc_fs.h>
19 #include <linux/random.h>
20 #include <linux/sched.h>
21 #include <linux/seq_file.h>
22 #include <linux/kallsyms.h>
23 #include <linux/kgdb.h>
24 #include <linux/ftrace.h>
26 #include <asm/atomic.h>
27 #include <asm/system.h>
28 #include <asm/uaccess.h>
34 static unsigned long irq_map
[NR_IRQS
/ BITS_PER_LONG
];
36 int allocate_irqno(void)
41 irq
= find_first_zero_bit(irq_map
, NR_IRQS
);
46 if (test_and_set_bit(irq
, irq_map
))
53 * Allocate the 16 legacy interrupts for i8259 devices. This happens early
54 * in the kernel initialization so treating allocation failure as BUG() is
57 void __init
alloc_legacy_irqno(void)
61 for (i
= 0; i
<= 16; i
++)
62 BUG_ON(test_and_set_bit(i
, irq_map
));
65 void free_irqno(unsigned int irq
)
67 smp_mb__before_clear_bit();
68 clear_bit(irq
, irq_map
);
69 smp_mb__after_clear_bit();
73 * 'what should we do if we get a hw irq event on an illegal vector'.
74 * each architecture has to answer this themselves.
76 void ack_bad_irq(unsigned int irq
)
79 printk("unexpected IRQ # %d\n", irq
);
82 atomic_t irq_err_count
;
84 int arch_show_interrupts(struct seq_file
*p
, int prec
)
86 seq_printf(p
, "%*s: %10u\n", prec
, "ERR", atomic_read(&irq_err_count
));
90 asmlinkage
void spurious_interrupt(void)
92 atomic_inc(&irq_err_count
);
95 void __init
init_IRQ(void)
100 if (kgdb_early_setup
)
104 for (i
= 0; i
< NR_IRQS
; i
++)
110 if (!kgdb_early_setup
)
111 kgdb_early_setup
= 1;
115 #ifdef DEBUG_STACKOVERFLOW
116 static inline void check_stack_overflow(void)
120 __asm__
__volatile__("move %0, $sp" : "=r" (sp
));
124 * Check for stack overflow: is there less than STACK_WARN free?
125 * STACK_WARN is defined as 1/8 of THREAD_SIZE by default.
127 if (unlikely(sp
< (sizeof(struct thread_info
) + STACK_WARN
))) {
128 printk("do_IRQ: stack overflow: %ld\n",
129 sp
- sizeof(struct thread_info
));
134 static inline void check_stack_overflow(void) {}
139 * do_IRQ handles all normal device IRQ's (the special
140 * SMP cross-CPU interrupts have their own specific
143 void __irq_entry
do_IRQ(unsigned int irq
)
146 check_stack_overflow();
147 if (!smtc_handle_on_other_cpu(irq
))
148 generic_handle_irq(irq
);
152 #ifdef CONFIG_MIPS_MT_SMTC_IRQAFF
154 * To avoid inefficient and in some cases pathological re-checking of
155 * IRQ affinity, we have this variant that skips the affinity check.
158 void __irq_entry
do_IRQ_no_affinity(unsigned int irq
)
161 smtc_im_backstop(irq
);
162 generic_handle_irq(irq
);
166 #endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */