| 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_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 | */ |
| 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 | |
| 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 | |
| 88 | asmlinkage void spurious_interrupt(void) |
| 89 | { |
| 90 | atomic_inc(&irq_err_count); |
| 91 | } |
| 92 | |
| 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 |
| 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 |
| 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 | */ |
| 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 | |
| 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 */ |