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  #include <linux/irqdomain.h>
25  
26  #include <linux/atomic.h>
27  #include <linux/uaccess.h>
28  
29  void *irq_stack[NR_CPUS];
30  
31  /*
32   * 'what should we do if we get a hw irq event on an illegal vector'.
33   * each architecture has to answer this themselves.
34   */
ack_bad_irq(unsigned int irq)35  void ack_bad_irq(unsigned int irq)
36  {
37  	printk("unexpected IRQ # %d\n", irq);
38  }
39  
40  atomic_t irq_err_count;
41  
arch_show_interrupts(struct seq_file * p,int prec)42  int arch_show_interrupts(struct seq_file *p, int prec)
43  {
44  	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
45  	return 0;
46  }
47  
spurious_interrupt(void)48  asmlinkage void spurious_interrupt(void)
49  {
50  	atomic_inc(&irq_err_count);
51  }
52  
init_IRQ(void)53  void __init init_IRQ(void)
54  {
55  	int i;
56  	unsigned int order = get_order(IRQ_STACK_SIZE);
57  
58  	for (i = 0; i < NR_IRQS; i++)
59  		irq_set_noprobe(i);
60  
61  	if (cpu_has_veic)
62  		clear_c0_status(ST0_IM);
63  
64  	arch_init_irq();
65  
66  	for_each_possible_cpu(i) {
67  		void *s = (void *)__get_free_pages(GFP_KERNEL, order);
68  
69  		irq_stack[i] = s;
70  		pr_debug("CPU%d IRQ stack at 0x%p - 0x%p\n", i,
71  			irq_stack[i], irq_stack[i] + IRQ_STACK_SIZE);
72  	}
73  }
74  
75  #ifdef CONFIG_DEBUG_STACKOVERFLOW
check_stack_overflow(void)76  static inline void check_stack_overflow(void)
77  {
78  	unsigned long sp;
79  
80  	__asm__ __volatile__("move %0, $sp" : "=r" (sp));
81  	sp &= THREAD_MASK;
82  
83  	/*
84  	 * Check for stack overflow: is there less than STACK_WARN free?
85  	 * STACK_WARN is defined as 1/8 of THREAD_SIZE by default.
86  	 */
87  	if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
88  		printk("do_IRQ: stack overflow: %ld\n",
89  		       sp - sizeof(struct thread_info));
90  		dump_stack();
91  	}
92  }
93  #else
check_stack_overflow(void)94  static inline void check_stack_overflow(void) {}
95  #endif
96  
97  
98  /*
99   * do_IRQ handles all normal device IRQ's (the special
100   * SMP cross-CPU interrupts have their own specific
101   * handlers).
102   */
do_IRQ(unsigned int irq)103  void __irq_entry do_IRQ(unsigned int irq)
104  {
105  	irq_enter();
106  	check_stack_overflow();
107  	generic_handle_irq(irq);
108  	irq_exit();
109  }
110  
111  #ifdef CONFIG_IRQ_DOMAIN
do_domain_IRQ(struct irq_domain * domain,unsigned int hwirq)112  void __irq_entry do_domain_IRQ(struct irq_domain *domain, unsigned int hwirq)
113  {
114  	irq_enter();
115  	check_stack_overflow();
116  	generic_handle_domain_irq(domain, hwirq);
117  	irq_exit();
118  }
119  #endif
120