arch/s390/kernel/s390_ext.c

   1 /*
   2  *  arch/s390/kernel/s390_ext.c
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Holger Smolinski (Holger.Smolinski@de.ibm.com),
   7  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/errno.h>
  14 #include <linux/kernel_stat.h>
  15
  16 #include <asm/lowcore.h>
  17 #include <asm/s390_ext.h>
  18 #include <asm/irq.h>
  19
  20 /*
  21  * Simple hash strategy: index = code & 0xff;
  22  * ext_int_hash[index] is the start of the list for all external interrupts
  23  * that hash to this index. With the current set of external interrupts
  24  * (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000
  25  * iucv and 0x2603 pfault) this is always the first element.
  26  */
  27 ext_int_info_t *ext_int_hash[256] = { 0, };
  28
  29 int register_external_interrupt(__u16 code, ext_int_handler_t handler)
  30 {
  31         ext_int_info_t *p;
  32         int index;
  33
  34         p = (ext_int_info_t *) kmalloc(sizeof(ext_int_info_t), GFP_ATOMIC);
  35         if (p == NULL)
  36                 return -ENOMEM;
  37         p->code = code;
  38         p->handler = handler;
  39         index = code & 0xff;
  40         p->next = ext_int_hash[index];
  41         ext_int_hash[index] = p;
  42         return 0;
  43 }
  44
  45 int register_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  46                                       ext_int_info_t *p)
  47 {
  48         int index;
  49
  50         if (p == NULL)
  51                 return -EINVAL;
  52         p->code = code;
  53         p->handler = handler;
  54         index = code & 0xff;
  55         p->next = ext_int_hash[index];
  56         ext_int_hash[index] = p;
  57         return 0;
  58 }
  59
  60 int unregister_external_interrupt(__u16 code, ext_int_handler_t handler)
  61 {
  62         ext_int_info_t *p, *q;
  63         int index;
  64
  65         index = code & 0xff;
  66         q = NULL;
  67         p = ext_int_hash[index];
  68         while (p != NULL) {
  69                 if (p->code == code && p->handler == handler)
  70                         break;
  71                 q = p;
  72                 p = p->next;
  73         }
  74         if (p == NULL)
  75                 return -ENOENT;
  76         if (q != NULL)
  77                 q->next = p->next;
  78         else
  79                 ext_int_hash[index] = p->next;
  80         kfree(p);
  81         return 0;
  82 }
  83
  84 int unregister_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  85                                         ext_int_info_t *p)
  86 {
  87         ext_int_info_t *q;
  88         int index;
  89
  90         if (p == NULL || p->code != code || p->handler != handler)
  91                 return -EINVAL;
  92         index = code & 0xff;
  93         q = ext_int_hash[index];
  94         if (p != q) {
  95                 while (q != NULL) {
  96                         if (q->next == p)
  97                                 break;
  98                         q = q->next;
  99                 }
 100                 if (q == NULL)
 101                         return -ENOENT;
 102                 q->next = p->next;
 103         } else
 104                 ext_int_hash[index] = p->next;
 105         return 0;
 106 }
 107
 108 void do_extint(struct pt_regs *regs, unsigned short code)
 109 {
 110         ext_int_info_t *p;
 111         int index;
 112
 113         irq_enter();
 114         asm volatile ("mc 0,0");
 115         if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)
 116                 account_ticks(regs);
 117         kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
 118         index = code & 0xff;
 119         for (p = ext_int_hash[index]; p; p = p->next) {
 120                 if (likely(p->code == code)) {
 121                         if (likely(p->handler))
 122                                 p->handler(regs, code);
 123                 }
 124         }
 125         irq_exit();
 126 }
 127
 128 EXPORT_SYMBOL(register_external_interrupt);
 129 EXPORT_SYMBOL(unregister_external_interrupt);
 130