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         get_online_cpus();
  29         if (i == 0) {
  30                 seq_puts(p, "           ");
  31                 for_each_online_cpu(j)
  32                         seq_printf(p, "CPU%d       ",j);
  33                 seq_putc(p, '\n');
  34         }
  35
  36         if (i < NR_IRQS) {
  37                 seq_printf(p, "%s: ", intrclass_names[i]);
  38 #ifndef CONFIG_SMP
  39                 seq_printf(p, "%10u ", kstat_irqs(i));
  40 #else
  41                 for_each_online_cpu(j)
  42                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  43 #endif
  44                 seq_putc(p, '\n');
  45
  46         }
  47         put_online_cpus();
  48         return 0;
  49 }
  50
  51 /*
  52  * For compatibilty only. S/390 specific setup of interrupts et al. is done
  53  * much later in init_channel_subsystem().
  54  */
  55 void __init
  56 init_IRQ(void)
  57 {
  58         /* nothing... */
  59 }
  60
  61 /*
  62  * Switch to the asynchronous interrupt stack for softirq execution.
  63  */
  64 asmlinkage void do_softirq(void)
  65 {
  66         unsigned long flags, old, new;
  67
  68         if (in_interrupt())
  69                 return;
  70
  71         local_irq_save(flags);
  72
  73         if (local_softirq_pending()) {
  74                 /* Get current stack pointer. */
  75                 asm volatile("la %0,0(15)" : "=a" (old));
  76                 /* Check against async. stack address range. */
  77                 new = S390_lowcore.async_stack;
  78                 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
  79                         /* Need to switch to the async. stack. */
  80                         new -= STACK_FRAME_OVERHEAD;
  81                         ((struct stack_frame *) new)->back_chain = old;
  82
  83                         asm volatile("   la    15,0(%0)\n"
  84                                      "   basr  14,%2\n"
  85                                      "   la    15,0(%1)\n"
  86                                      : : "a" (new), "a" (old),
  87                                          "a" (__do_softirq)
  88                                      : "0", "1", "2", "3", "4", "5", "14",
  89                                        "cc", "memory" );
  90                 } else
  91                         /* We are already on the async stack. */
  92                         __do_softirq();
  93         }
  94
  95         local_irq_restore(flags);
  96 }
  97
  98 void init_irq_proc(void)
  99 {
 100         struct proc_dir_entry *root_irq_dir;
 101
 102         root_irq_dir = proc_mkdir("irq", NULL);
 103         create_prof_cpu_mask(root_irq_dir);
 104 }