arch/x86/kernel/irq_64.c

   1 /*
   2  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
   3  *
   4  * This file contains the lowest level x86_64-specific interrupt
   5  * entry and irq statistics code. All the remaining irq logic is
   6  * done by the generic kernel/irq/ code and in the
   7  * x86_64-specific irq controller code. (e.g. i8259.c and
   8  * io_apic.c.)
   9  */
  10
  11 #include <linux/kernel_stat.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/module.h>
  15 #include <linux/delay.h>
  16 #include <linux/ftrace.h>
  17 #include <asm/uaccess.h>
  18 #include <asm/io_apic.h>
  19 #include <asm/idle.h>
  20 #include <asm/smp.h>
  21
  22 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  23 /*
  24  * Probabilistic stack overflow check:
  25  *
  26  * Only check the stack in process context, because everything else
  27  * runs on the big interrupt stacks. Checking reliably is too expensive,
  28  * so we just check from interrupts.
  29  */
  30 static inline void stack_overflow_check(struct pt_regs *regs)
  31 {
  32         u64 curbase = (u64)task_stack_page(current);
  33         static unsigned long warned = -60*HZ;
  34
  35         if (regs->sp >= curbase && regs->sp <= curbase + THREAD_SIZE &&
  36             regs->sp <  curbase + sizeof(struct thread_info) + 128 &&
  37             time_after(jiffies, warned + 60*HZ)) {
  38                 printk("do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
  39                        current->comm, curbase, regs->sp);
  40                 show_stack(NULL,NULL);
  41                 warned = jiffies;
  42         }
  43 }
  44 #endif
  45
  46 /*
  47  * do_IRQ handles all normal device IRQ's (the special
  48  * SMP cross-CPU interrupts have their own specific
  49  * handlers).
  50  */
  51 asmlinkage unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
  52 {
  53         struct pt_regs *old_regs = set_irq_regs(regs);
  54         struct irq_desc *desc;
  55
  56         /* high bit used in ret_from_ code  */
  57         unsigned vector = ~regs->orig_ax;
  58         unsigned irq;
  59
  60         exit_idle();
  61         irq_enter();
  62         irq = __get_cpu_var(vector_irq)[vector];
  63
  64 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  65         stack_overflow_check(regs);
  66 #endif
  67
  68         desc = irq_to_desc(irq);
  69         if (likely(desc))
  70                 generic_handle_irq_desc(irq, desc);
  71         else {
  72                 if (!disable_apic)
  73                         ack_APIC_irq();
  74
  75                 if (printk_ratelimit())
  76                         printk(KERN_EMERG "%s: %d.%d No irq handler for vector\n",
  77                                 __func__, smp_processor_id(), vector);
  78         }
  79
  80         irq_exit();
  81
  82         set_irq_regs(old_regs);
  83         return 1;
  84 }
  85
  86 #ifdef CONFIG_HOTPLUG_CPU
  87 void fixup_irqs(cpumask_t map)
  88 {
  89         unsigned int irq;
  90         static int warned;
  91         struct irq_desc *desc;
  92
  93         for_each_irq_desc(irq, desc) {
  94                 cpumask_t mask;
  95                 int break_affinity = 0;
  96                 int set_affinity = 1;
  97
  98                 if (irq == 2)
  99                         continue;
 100
 101                 /* interrupt's are disabled at this point */
 102                 spin_lock(&desc->lock);
 103
 104                 if (!irq_has_action(irq) ||
 105                     cpus_equal(desc->affinity, map)) {
 106                         spin_unlock(&desc->lock);
 107                         continue;
 108                 }
 109
 110                 cpus_and(mask, desc->affinity, map);
 111                 if (cpus_empty(mask)) {
 112                         break_affinity = 1;
 113                         mask = map;
 114                 }
 115
 116                 if (desc->chip->mask)
 117                         desc->chip->mask(irq);
 118
 119                 if (desc->chip->set_affinity)
 120                         desc->chip->set_affinity(irq, mask);
 121                 else if (!(warned++))
 122                         set_affinity = 0;
 123
 124                 if (desc->chip->unmask)
 125                         desc->chip->unmask(irq);
 126
 127                 spin_unlock(&desc->lock);
 128
 129                 if (break_affinity && set_affinity)
 130                         printk("Broke affinity for irq %i\n", irq);
 131                 else if (!set_affinity)
 132                         printk("Cannot set affinity for irq %i\n", irq);
 133         }
 134
 135         /* That doesn't seem sufficient.  Give it 1ms. */
 136         local_irq_enable();
 137         mdelay(1);
 138         local_irq_disable();
 139 }
 140 #endif
 141
 142 extern void call_softirq(void);
 143
 144 asmlinkage void do_softirq(void)
 145 {
 146         __u32 pending;
 147         unsigned long flags;
 148
 149         if (in_interrupt())
 150                 return;
 151
 152         local_irq_save(flags);
 153         pending = local_softirq_pending();
 154         /* Switch to interrupt stack */
 155         if (pending) {
 156                 call_softirq();
 157                 WARN_ON_ONCE(softirq_count());
 158         }
 159         local_irq_restore(flags);
 160 }