arch/mips/kernel/irq.c

   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
  28 void *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  */
  34 void ack_bad_irq(unsigned int irq)
  35 {
  36         printk("unexpected IRQ # %d\n", irq);
  37 }
  38
  39 atomic_t irq_err_count;
  40
  41 int 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
  47 asmlinkage void spurious_interrupt(void)
  48 {
  49         atomic_inc(&irq_err_count);
  50 }
  51
  52 void __init init_IRQ(void)
  53 {
  54         int i;
  55
  56         for (i = 0; i < NR_IRQS; i++)
  57                 irq_set_noprobe(i);
  58
  59         if (cpu_has_veic)
  60                 clear_c0_status(ST0_IM);
  61
  62         arch_init_irq();
  63
  64         for_each_possible_cpu(i) {
  65                 int irq_pages = IRQ_STACK_SIZE / PAGE_SIZE;
  66                 void *s = (void *)__get_free_pages(GFP_KERNEL, irq_pages);
  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
  75 static 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
  93 static 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  */
 102 void __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