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
allocate_irqno(void)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 */
alloc_legacy_irqno(void)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
free_irqno(unsigned int irq)63 void free_irqno(unsigned int irq)
64 {
65 smp_mb__before_clear_bit();
66 clear_bit(irq, irq_map);
67 smp_mb__after_clear_bit();
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 */
ack_bad_irq(unsigned int irq)74 void ack_bad_irq(unsigned int irq)
75 {
76 smtc_im_ack_irq(irq);
77 printk("unexpected IRQ # %d\n", irq);
78 }
79
80 atomic_t irq_err_count;
81
arch_show_interrupts(struct seq_file * p,int prec)82 int arch_show_interrupts(struct seq_file *p, int prec)
83 {
84 seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
85 return 0;
86 }
87
spurious_interrupt(void)88 asmlinkage void spurious_interrupt(void)
89 {
90 atomic_inc(&irq_err_count);
91 }
92
init_IRQ(void)93 void __init init_IRQ(void)
94 {
95 int i;
96
97 #ifdef CONFIG_KGDB
98 if (kgdb_early_setup)
99 return;
100 #endif
101
102 for (i = 0; i < NR_IRQS; i++)
103 irq_set_noprobe(i);
104
105 arch_init_irq();
106
107 #ifdef CONFIG_KGDB
108 if (!kgdb_early_setup)
109 kgdb_early_setup = 1;
110 #endif
111 }
112
113 #ifdef DEBUG_STACKOVERFLOW
check_stack_overflow(void)114 static inline void check_stack_overflow(void)
115 {
116 unsigned long sp;
117
118 __asm__ __volatile__("move %0, $sp" : "=r" (sp));
119 sp &= THREAD_MASK;
120
121 /*
122 * Check for stack overflow: is there less than STACK_WARN free?
123 * STACK_WARN is defined as 1/8 of THREAD_SIZE by default.
124 */
125 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
126 printk("do_IRQ: stack overflow: %ld\n",
127 sp - sizeof(struct thread_info));
128 dump_stack();
129 }
130 }
131 #else
check_stack_overflow(void)132 static inline void check_stack_overflow(void) {}
133 #endif
134
135
136 /*
137 * do_IRQ handles all normal device IRQ's (the special
138 * SMP cross-CPU interrupts have their own specific
139 * handlers).
140 */
do_IRQ(unsigned int irq)141 void __irq_entry do_IRQ(unsigned int irq)
142 {
143 irq_enter();
144 check_stack_overflow();
145 if (!smtc_handle_on_other_cpu(irq))
146 generic_handle_irq(irq);
147 irq_exit();
148 }
149
150 #ifdef CONFIG_MIPS_MT_SMTC_IRQAFF
151 /*
152 * To avoid inefficient and in some cases pathological re-checking of
153 * IRQ affinity, we have this variant that skips the affinity check.
154 */
155
do_IRQ_no_affinity(unsigned int irq)156 void __irq_entry do_IRQ_no_affinity(unsigned int irq)
157 {
158 irq_enter();
159 smtc_im_backstop(irq);
160 generic_handle_irq(irq);
161 irq_exit();
162 }
163
164 #endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */
165