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irq_64.c

/*
 *    Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
 *
 * This file contains the lowest level x86_64-specific interrupt
 * entry and irq statistics code. All the remaining irq logic is
 * done by the generic kernel/irq/ code and in the
 * x86_64-specific irq controller code. (e.g. i8259.c and
 * io_apic.c.)
 */

#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
#include <asm/io_apic.h>
#include <asm/idle.h>
#include <asm/smp.h>

atomic_t irq_err_count;

#ifdef CONFIG_DEBUG_STACKOVERFLOW
/*
 * Probabilistic stack overflow check:
 *
 * Only check the stack in process context, because everything else
 * runs on the big interrupt stacks. Checking reliably is too expensive,
 * so we just check from interrupts.
 */
static inline void stack_overflow_check(struct pt_regs *regs)
{
      u64 curbase = (u64)task_stack_page(current);
      static unsigned long warned = -60*HZ;

      if (regs->rsp >= curbase && regs->rsp <= curbase + THREAD_SIZE &&
          regs->rsp <  curbase + sizeof(struct thread_info) + 128 &&
          time_after(jiffies, warned + 60*HZ)) {
            printk("do_IRQ: %s near stack overflow (cur:%Lx,rsp:%lx)\n",
                   current->comm, curbase, regs->rsp);
            show_stack(NULL,NULL);
            warned = jiffies;
      }
}
#endif

/*
 * Generic, controller-independent functions:
 */

int show_interrupts(struct seq_file *p, void *v)
{
      int i = *(loff_t *) v, j;
      struct irqaction * action;
      unsigned long flags;

      if (i == 0) {
            seq_printf(p, "           ");
            for_each_online_cpu(j)
                  seq_printf(p, "CPU%-8d",j);
            seq_putc(p, '\n');
      }

      if (i < NR_IRQS) {
            unsigned any_count = 0;

            spin_lock_irqsave(&irq_desc[i].lock, flags);
#ifndef CONFIG_SMP
            any_count = kstat_irqs(i);
#else
            for_each_online_cpu(j)
                  any_count |= kstat_cpu(j).irqs[i];
#endif
            action = irq_desc[i].action;
            if (!action && !any_count)
                  goto skip;
            seq_printf(p, "%3d: ",i);
#ifndef CONFIG_SMP
            seq_printf(p, "%10u ", kstat_irqs(i));
#else
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
#endif
            seq_printf(p, " %8s", irq_desc[i].chip->name);
            seq_printf(p, "-%-8s", irq_desc[i].name);

            if (action) {
                  seq_printf(p, "  %s", action->name);
                  while ((action = action->next) != NULL)
                        seq_printf(p, ", %s", action->name);
            }
            seq_putc(p, '\n');
skip:
            spin_unlock_irqrestore(&irq_desc[i].lock, flags);
      } else if (i == NR_IRQS) {
            seq_printf(p, "NMI: ");
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", cpu_pda(j)->__nmi_count);
            seq_printf(p, "  Non-maskable interrupts\n");
            seq_printf(p, "LOC: ");
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", cpu_pda(j)->apic_timer_irqs);
            seq_printf(p, "  Local timer interrupts\n");
#ifdef CONFIG_SMP
            seq_printf(p, "RES: ");
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", cpu_pda(j)->irq_resched_count);
            seq_printf(p, "  Rescheduling interrupts\n");
            seq_printf(p, "CAL: ");
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", cpu_pda(j)->irq_call_count);
            seq_printf(p, "  function call interrupts\n");
            seq_printf(p, "TLB: ");
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", cpu_pda(j)->irq_tlb_count);
            seq_printf(p, "  TLB shootdowns\n");
#endif
            seq_printf(p, "TRM: ");
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", cpu_pda(j)->irq_thermal_count);
            seq_printf(p, "  Thermal event interrupts\n");
            seq_printf(p, "THR: ");
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", cpu_pda(j)->irq_threshold_count);
            seq_printf(p, "  Threshold APIC interrupts\n");
            seq_printf(p, "SPU: ");
            for_each_online_cpu(j)
                  seq_printf(p, "%10u ", cpu_pda(j)->irq_spurious_count);
            seq_printf(p, "  Spurious interrupts\n");
            seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
      }
      return 0;
}

/*
 * do_IRQ handles all normal device IRQ's (the special
 * SMP cross-CPU interrupts have their own specific
 * handlers).
 */
asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
{
      struct pt_regs *old_regs = set_irq_regs(regs);

      /* high bit used in ret_from_ code  */
      unsigned vector = ~regs->orig_rax;
      unsigned irq;

      exit_idle();
      irq_enter();
      irq = __get_cpu_var(vector_irq)[vector];

#ifdef CONFIG_DEBUG_STACKOVERFLOW
      stack_overflow_check(regs);
#endif

      if (likely(irq < NR_IRQS))
            generic_handle_irq(irq);
      else {
            if (!disable_apic)
                  ack_APIC_irq();

            if (printk_ratelimit())
                  printk(KERN_EMERG "%s: %d.%d No irq handler for vector\n",
                        __func__, smp_processor_id(), vector);
      }

      irq_exit();

      set_irq_regs(old_regs);
      return 1;
}

#ifdef CONFIG_HOTPLUG_CPU
void fixup_irqs(cpumask_t map)
{
      unsigned int irq;
      static int warned;

      for (irq = 0; irq < NR_IRQS; irq++) {
            cpumask_t mask;
            int break_affinity = 0;
            int set_affinity = 1;

            if (irq == 2)
                  continue;

            /* interrupt's are disabled at this point */
            spin_lock(&irq_desc[irq].lock);

            if (!irq_has_action(irq) ||
                cpus_equal(irq_desc[irq].affinity, map)) {
                  spin_unlock(&irq_desc[irq].lock);
                  continue;
            }

            cpus_and(mask, irq_desc[irq].affinity, map);
            if (cpus_empty(mask)) {
                  break_affinity = 1;
                  mask = map;
            }

            if (irq_desc[irq].chip->mask)
                  irq_desc[irq].chip->mask(irq);

            if (irq_desc[irq].chip->set_affinity)
                  irq_desc[irq].chip->set_affinity(irq, mask);
            else if (!(warned++))
                  set_affinity = 0;

            if (irq_desc[irq].chip->unmask)
                  irq_desc[irq].chip->unmask(irq);

            spin_unlock(&irq_desc[irq].lock);

            if (break_affinity && set_affinity)
                  printk("Broke affinity for irq %i\n", irq);
            else if (!set_affinity)
                  printk("Cannot set affinity for irq %i\n", irq);
      }

      /* That doesn't seem sufficient.  Give it 1ms. */
      local_irq_enable();
      mdelay(1);
      local_irq_disable();
}
#endif

extern void call_softirq(void);

asmlinkage void do_softirq(void)
{
      __u32 pending;
      unsigned long flags;

      if (in_interrupt())
            return;

      local_irq_save(flags);
      pending = local_softirq_pending();
      /* Switch to interrupt stack */
      if (pending) {
            call_softirq();
            WARN_ON_ONCE(softirq_count());
      }
      local_irq_restore(flags);
}

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