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 /*
  21  * show_interrupts is needed by /proc/interrupts.
  22  */
  23 int show_interrupts(struct seq_file *p, void *v)
  24 {
  25         static const char *intrclass_names[] = { "EXT", "I/O", };
  26         int i = *(loff_t *) v, j;
  27
  28         if (i == 0) {
  29                 seq_puts(p, "           ");
  30                 for_each_online_cpu(j)
  31                         seq_printf(p, "CPU%d       ",j);
  32                 seq_putc(p, '\n');
  33         }
  34
  35         if (i < NR_IRQS) {
  36                 seq_printf(p, "%s: ", intrclass_names[i]);
  37 #ifndef CONFIG_SMP
  38                 seq_printf(p, "%10u ", kstat_irqs(i));
  39 #else
  40                 for_each_online_cpu(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 asmlinkage void do_softirq(void)
  64 {
  65         unsigned long flags, old, new;
  66
  67         if (in_interrupt())
  68                 return;
  69
  70         local_irq_save(flags);
  71
  72         if (local_softirq_pending()) {
  73                 /* Get current stack pointer. */
  74                 asm volatile("la %0,0(15)" : "=a" (old));
  75                 /* Check against async. stack address range. */
  76                 new = S390_lowcore.async_stack;
  77                 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
  78                         /* Need to switch to the async. stack. */
  79                         new -= STACK_FRAME_OVERHEAD;
  80                         ((struct stack_frame *) new)->back_chain = old;
  81
  82                         asm volatile("   la    15,0(%0)\n"
  83                                      "   basr  14,%2\n"
  84                                      "   la    15,0(%1)\n"
  85                                      : : "a" (new), "a" (old),
  86                                          "a" (__do_softirq)
  87                                      : "0", "1", "2", "3", "4", "5", "14",
  88                                        "cc", "memory" );
  89                 } else
  90                         /* We are already on the async stack. */
  91                         __do_softirq();
  92         }
  93
  94         local_irq_restore(flags);
  95 }
  96
  97 void init_irq_proc(void)
  98 {
  99         struct proc_dir_entry *root_irq_dir;
 100
 101         root_irq_dir = proc_mkdir("irq", NULL);
 102         create_prof_cpu_mask(root_irq_dir);
 103 }