arch/s390/kernel/irq.c

   1 /*
   2  *  arch/s390/kernel/irq.c
   3  *
   4  *    Copyright IBM Corp. 2004,2007
   5  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
   6  *               Thomas Spatzier (tspat@de.ibm.com)
   7  *
   8  * This file contains interrupt related functions.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/kernel_stat.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/cpu.h>
  17 #include <linux/proc_fs.h>
  18 #include <linux/profile.h>
  19
  20 int nr_irqs = NR_IRQS;
  21 EXPORT_SYMBOL(nr_irqs);
  22
  23 /*
  24  * show_interrupts is needed by /proc/interrupts.
  25  */
  26 int show_interrupts(struct seq_file *p, void *v)
  27 {
  28         static const char *intrclass_names[] = { "EXT", "I/O", };
  29         int i = *(loff_t *) v, j;
  30
  31         get_online_cpus();
  32         if (i == 0) {
  33                 seq_puts(p, "           ");
  34                 for_each_online_cpu(j)
  35                         seq_printf(p, "CPU%d       ",j);
  36                 seq_putc(p, '\n');
  37         }
  38
  39         if (i < NR_IRQS) {
  40                 seq_printf(p, "%s: ", intrclass_names[i]);
  41 #ifndef CONFIG_SMP
  42                 seq_printf(p, "%10u ", kstat_irqs(i));
  43 #else
  44                 for_each_online_cpu(j)
  45                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  46 #endif
  47                 seq_putc(p, '\n');
  48
  49         }
  50         put_online_cpus();
  51         return 0;
  52 }
  53
  54 /*
  55  * For compatibilty only. S/390 specific setup of interrupts et al. is done
  56  * much later in init_channel_subsystem().
  57  */
  58 void __init
  59 init_IRQ(void)
  60 {
  61         /* nothing... */
  62 }
  63
  64 /*
  65  * Switch to the asynchronous interrupt stack for softirq execution.
  66  */
  67 asmlinkage void do_softirq(void)
  68 {
  69         unsigned long flags, old, new;
  70
  71         if (in_interrupt())
  72                 return;
  73
  74         local_irq_save(flags);
  75
  76         if (local_softirq_pending()) {
  77                 /* Get current stack pointer. */
  78                 asm volatile("la %0,0(15)" : "=a" (old));
  79                 /* Check against async. stack address range. */
  80                 new = S390_lowcore.async_stack;
  81                 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
  82                         /* Need to switch to the async. stack. */
  83                         new -= STACK_FRAME_OVERHEAD;
  84                         ((struct stack_frame *) new)->back_chain = old;
  85
  86                         asm volatile("   la    15,0(%0)\n"
  87                                      "   basr  14,%2\n"
  88                                      "   la    15,0(%1)\n"
  89                                      : : "a" (new), "a" (old),
  90                                          "a" (__do_softirq)
  91                                      : "0", "1", "2", "3", "4", "5", "14",
  92                                        "cc", "memory" );
  93                 } else
  94                         /* We are already on the async stack. */
  95                         __do_softirq();
  96         }
  97
  98         local_irq_restore(flags);
  99 }
 100
 101 void init_irq_proc(void)
 102 {
 103         struct proc_dir_entry *root_irq_dir;
 104
 105         root_irq_dir = proc_mkdir("irq", NULL);
 106         create_prof_cpu_mask(root_irq_dir);
 107 }