arch/s390/kernel/irq.c

   1 /*
   2  *  arch/s390/kernel/irq.c
   3  *
   4  *  S390 version
   5  *    Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Martin Schwidefsky (schwidefsky@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
  18 /*
  19  * show_interrupts is needed by /proc/interrupts.
  20  */
  21 int show_interrupts(struct seq_file *p, void *v)
  22 {
  23         static const char *intrclass_names[] = { "EXT", "I/O", };
  24         int i = *(loff_t *) v, j;
  25
  26         if (i == 0) {
  27                 seq_puts(p, "           ");
  28                 for (j=0; j<NR_CPUS; j++)
  29                         if (cpu_online(j))
  30                                 seq_printf(p, "CPU%d       ",j);
  31                 seq_putc(p, '\n');
  32         }
  33
  34         if (i < NR_IRQS) {
  35                 seq_printf(p, "%s: ", intrclass_names[i]);
  36 #ifndef CONFIG_SMP
  37                 seq_printf(p, "%10u ", kstat_irqs(i));
  38 #else
  39                 for (j = 0; j < NR_CPUS; j++)
  40                         if (cpu_online(j))
  41                                 seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  42 #endif
  43                 seq_putc(p, '\n');
  44
  45         }
  46
  47         return 0;
  48 }
  49
  50 /*
  51  * For compatibilty only. S/390 specific setup of interrupts et al. is done
  52  * much later in init_channel_subsystem().
  53  */
  54 void __init
  55 init_IRQ(void)
  56 {
  57         /* nothing... */
  58 }
  59
  60 /*
  61  * Switch to the asynchronous interrupt stack for softirq execution.
  62  */
  63 extern void __do_softirq(void);
  64
  65 asmlinkage void do_softirq(void)
  66 {
  67         unsigned long flags, old, new;
  68
  69         if (in_interrupt())
  70                 return;
  71
  72         local_irq_save(flags);
  73
  74         if (local_softirq_pending()) {
  75                 /* Get current stack pointer. */
  76                 asm volatile("la %0,0(15)" : "=a" (old));
  77                 /* Check against async. stack address range. */
  78                 new = S390_lowcore.async_stack;
  79                 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
  80                         /* Need to switch to the async. stack. */
  81                         new -= STACK_FRAME_OVERHEAD;
  82                         ((struct stack_frame *) new)->back_chain = old;
  83
  84                         asm volatile("   la    15,0(%0)\n"
  85                                      "   basr  14,%2\n"
  86                                      "   la    15,0(%1)\n"
  87                                      : : "a" (new), "a" (old),
  88                                          "a" (__do_softirq)
  89                                      : "0", "1", "2", "3", "4", "5",
  90                                        "cc", "memory" );
  91                 } else
  92                         /* We are already on the async stack. */
  93                         __do_softirq();
  94         }
  95
  96         local_irq_restore(flags);
  97 }
  98
  99 EXPORT_SYMBOL(do_softirq);