linux/arch/mips/kernel/irq.c
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   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 <linux/uaccess.h>
  27
  28void *irq_stack[NR_CPUS];
  29
  30/*
  31 * 'what should we do if we get a hw irq event on an illegal vector'.
  32 * each architecture has to answer this themselves.
  33 */
  34void ack_bad_irq(unsigned int irq)
  35{
  36        printk("unexpected IRQ # %d\n", irq);
  37}
  38
  39atomic_t irq_err_count;
  40
  41int arch_show_interrupts(struct seq_file *p, int prec)
  42{
  43        seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
  44        return 0;
  45}
  46
  47asmlinkage void spurious_interrupt(void)
  48{
  49        atomic_inc(&irq_err_count);
  50}
  51
  52void __init init_IRQ(void)
  53{
  54        int i;
  55        unsigned int order = get_order(IRQ_STACK_SIZE);
  56
  57        for (i = 0; i < NR_IRQS; i++)
  58                irq_set_noprobe(i);
  59
  60        if (cpu_has_veic)
  61                clear_c0_status(ST0_IM);
  62
  63        arch_init_irq();
  64
  65        for_each_possible_cpu(i) {
  66                void *s = (void *)__get_free_pages(GFP_KERNEL, order);
  67
  68                irq_stack[i] = s;
  69                pr_debug("CPU%d IRQ stack at 0x%p - 0x%p\n", i,
  70                        irq_stack[i], irq_stack[i] + IRQ_STACK_SIZE);
  71        }
  72}
  73
  74#ifdef CONFIG_DEBUG_STACKOVERFLOW
  75static inline void check_stack_overflow(void)
  76{
  77        unsigned long sp;
  78
  79        __asm__ __volatile__("move %0, $sp" : "=r" (sp));
  80        sp &= THREAD_MASK;
  81
  82        /*
  83         * Check for stack overflow: is there less than STACK_WARN free?
  84         * STACK_WARN is defined as 1/8 of THREAD_SIZE by default.
  85         */
  86        if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
  87                printk("do_IRQ: stack overflow: %ld\n",
  88                       sp - sizeof(struct thread_info));
  89                dump_stack();
  90        }
  91}
  92#else
  93static inline void check_stack_overflow(void) {}
  94#endif
  95
  96
  97/*
  98 * do_IRQ handles all normal device IRQ's (the special
  99 * SMP cross-CPU interrupts have their own specific
 100 * handlers).
 101 */
 102void __irq_entry do_IRQ(unsigned int irq)
 103{
 104        irq_enter();
 105        check_stack_overflow();
 106        generic_handle_irq(irq);
 107        irq_exit();
 108}
 109
 110