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 <asm/uaccess.h>
  17 #include <asm/io_apic.h>
  18 #include <asm/idle.h>
  19 #include <asm/smp.h>
  20
  21 /*
  22  * 'what should we do if we get a hw irq event on an illegal vector'.
  23  * each architecture has to answer this themselves.
  24  */
  25 void ack_bad_irq(unsigned int irq)
  26 {
  27         printk(KERN_WARNING "unexpected IRQ trap at vector %02x\n", irq);
  28         /*
  29          * Currently unexpected vectors happen only on SMP and APIC.
  30          * We _must_ ack these because every local APIC has only N
  31          * irq slots per priority level, and a 'hanging, unacked' IRQ
  32          * holds up an irq slot - in excessive cases (when multiple
  33          * unexpected vectors occur) that might lock up the APIC
  34          * completely.
  35          * But don't ack when the APIC is disabled. -AK
  36          */
  37         if (!disable_apic)
  38                 ack_APIC_irq();
  39 }
  40
  41 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  42 /*
  43  * Probabilistic stack overflow check:
  44  *
  45  * Only check the stack in process context, because everything else
  46  * runs on the big interrupt stacks. Checking reliably is too expensive,
  47  * so we just check from interrupts.
  48  */
  49 static inline void stack_overflow_check(struct pt_regs *regs)
  50 {
  51         u64 curbase = (u64)task_stack_page(current);
  52         static unsigned long warned = -60*HZ;
  53
  54         if (regs->sp >= curbase && regs->sp <= curbase + THREAD_SIZE &&
  55             regs->sp <  curbase + sizeof(struct thread_info) + 128 &&
  56             time_after(jiffies, warned + 60*HZ)) {
  57                 printk("do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
  58                        current->comm, curbase, regs->sp);
  59                 show_stack(NULL,NULL);
  60                 warned = jiffies;
  61         }
  62 }
  63 #endif
  64
  65 /*
  66  * do_IRQ handles all normal device IRQ's (the special
  67  * SMP cross-CPU interrupts have their own specific
  68  * handlers).
  69  */
  70 asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
  71 {
  72         struct pt_regs *old_regs = set_irq_regs(regs);
  73         struct irq_desc *desc;
  74
  75         /* high bit used in ret_from_ code  */
  76         unsigned vector = ~regs->orig_ax;
  77         unsigned irq;
  78
  79         exit_idle();
  80         irq_enter();
  81         irq = __get_cpu_var(vector_irq)[vector];
  82
  83 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  84         stack_overflow_check(regs);
  85 #endif
  86
  87         desc = irq_to_desc(irq);
  88         if (likely(desc))
  89                 generic_handle_irq_desc(irq, desc);
  90         else {
  91                 if (!disable_apic)
  92                         ack_APIC_irq();
  93
  94                 if (printk_ratelimit())
  95                         printk(KERN_EMERG "%s: %d.%d No irq handler for vector\n",
  96                                 __func__, smp_processor_id(), vector);
  97         }
  98
  99         irq_exit();
 100
 101         set_irq_regs(old_regs);
 102         return 1;
 103 }
 104
 105 #ifdef CONFIG_HOTPLUG_CPU
 106 void fixup_irqs(cpumask_t map)
 107 {
 108         unsigned int irq;
 109         static int warned;
 110         struct irq_desc *desc;
 111
 112         for_each_irq_desc(irq, desc) {
 113                 cpumask_t mask;
 114                 int break_affinity = 0;
 115                 int set_affinity = 1;
 116
 117                 if (irq == 2)
 118                         continue;
 119
 120                 /* interrupt's are disabled at this point */
 121                 spin_lock(&desc->lock);
 122
 123                 if (!irq_has_action(irq) ||
 124                     cpus_equal(desc->affinity, map)) {
 125                         spin_unlock(&desc->lock);
 126                         continue;
 127                 }
 128
 129                 cpus_and(mask, desc->affinity, map);
 130                 if (cpus_empty(mask)) {
 131                         break_affinity = 1;
 132                         mask = map;
 133                 }
 134
 135                 if (desc->chip->mask)
 136                         desc->chip->mask(irq);
 137
 138                 if (desc->chip->set_affinity)
 139                         desc->chip->set_affinity(irq, mask);
 140                 else if (!(warned++))
 141                         set_affinity = 0;
 142
 143                 if (desc->chip->unmask)
 144                         desc->chip->unmask(irq);
 145
 146                 spin_unlock(&desc->lock);
 147
 148                 if (break_affinity && set_affinity)
 149                         printk("Broke affinity for irq %i\n", irq);
 150                 else if (!set_affinity)
 151                         printk("Cannot set affinity for irq %i\n", irq);
 152         }
 153
 154         /* That doesn't seem sufficient.  Give it 1ms. */
 155         local_irq_enable();
 156         mdelay(1);
 157         local_irq_disable();
 158 }
 159 #endif
 160
 161 extern void call_softirq(void);
 162
 163 asmlinkage void do_softirq(void)
 164 {
 165         __u32 pending;
 166         unsigned long flags;
 167
 168         if (in_interrupt())
 169                 return;
 170
 171         local_irq_save(flags);
 172         pending = local_softirq_pending();
 173         /* Switch to interrupt stack */
 174         if (pending) {
 175                 call_softirq();
 176                 WARN_ON_ONCE(softirq_count());
 177         }
 178         local_irq_restore(flags);
 179 }