arch/s390x/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 <asm/lowcore.h>
  14 #include <asm/s390_ext.h>
  15
  16 /*
  17  * Simple hash strategy: index = code & 0xff;
  18  * ext_int_hash[index] is the start of the list for all external interrupts
  19  * that hash to this index. With the current set of external interrupts
  20  * (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000
  21  * iucv and 0x2603 pfault) this is always the first element.
  22  */
  23 ext_int_info_t *ext_int_hash[256] = { 0, };
  24
  25 int register_external_interrupt(__u16 code, ext_int_handler_t handler) {
  26         ext_int_info_t *p;
  27         int index;
  28
  29         p = (ext_int_info_t *) kmalloc(sizeof(ext_int_info_t), GFP_ATOMIC);
  30         if (p == NULL)
  31                 return -ENOMEM;
  32         p->code = code;
  33         p->handler = handler;
  34         index = code & 0xff;
  35         p->next = ext_int_hash[index];
  36         ext_int_hash[index] = p;
  37         return 0;
  38 }
  39
  40 int register_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  41                                       ext_int_info_t *p) {
  42         int index;
  43
  44         if (p == NULL)
  45                 return -EINVAL;
  46         p->code = code;
  47         p->handler = handler;
  48         index = code & 0xff;
  49         p->next = ext_int_hash[index];
  50         ext_int_hash[index] = p;
  51         return 0;
  52 }
  53
  54 int unregister_external_interrupt(__u16 code, ext_int_handler_t handler) {
  55         ext_int_info_t *p, *q;
  56         int index;
  57
  58         index = code & 0xff;
  59         q = NULL;
  60         p = ext_int_hash[index];
  61         while (p != NULL) {
  62                 if (p->code == code && p->handler == handler)
  63                         break;
  64                 q = p;
  65                 p = p->next;
  66         }
  67         if (p == NULL)
  68                 return -ENOENT;
  69         if (q != NULL)
  70                 q->next = p->next;
  71         else
  72                 ext_int_hash[index] = p->next;
  73         kfree(p);
  74         return 0;
  75 }
  76
  77 int unregister_early_external_interrupt(__u16 code, ext_int_handler_t handler,
  78                                         ext_int_info_t *p) {
  79         ext_int_info_t *q;
  80         int index;
  81
  82         if (p == NULL || p->code != code || p->handler != handler)
  83                 return -EINVAL;
  84         index = code & 0xff;
  85         q = ext_int_hash[index];
  86         if (p != q) {
  87                 while (q != NULL) {
  88                         if (q->next == p)
  89                                 break;
  90                         q = q->next;
  91                 }
  92                 if (q == NULL)
  93                         return -ENOENT;
  94                 q->next = p->next;
  95         } else
  96                 ext_int_hash[index] = p->next;
  97         return 0;
  98 }
  99
 100 EXPORT_SYMBOL(register_external_interrupt);
 101 EXPORT_SYMBOL(unregister_external_interrupt);
 102