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
29int kgdb_early_setup;
30#endif
31
32static DECLARE_BITMAP(irq_map, NR_IRQS);
33
34int allocate_irqno(void)
35{
36	int irq;
37
38again:
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 */
55void __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
63void 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 */
74void ack_bad_irq(unsigned int irq)
75{
76	printk("unexpected IRQ # %d\n", irq);
77}
78
79atomic_t irq_err_count;
80
81int 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
87asmlinkage void spurious_interrupt(void)
88{
89	atomic_inc(&irq_err_count);
90}
91
92void __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 CONFIG_DEBUG_STACKOVERFLOW
113static 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
131static 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 */
140void __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
148