arch/s390/kernel/s390_ext.c

   1 /*
   2  *    Copyright IBM Corp. 1999,2010
   3  *    Author(s): Holger Smolinski <Holger.Smolinski@de.ibm.com>,
   4  *               Martin Schwidefsky <schwidefsky@de.ibm.com>,
   5  */
   6
   7 #include <linux/kernel_stat.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/module.h>
  10 #include <linux/kernel.h>
  11 #include <linux/ftrace.h>
  12 #include <linux/errno.h>
  13 #include <linux/slab.h>
  14 #include <asm/s390_ext.h>
  15 #include <asm/irq_regs.h>
  16 #include <asm/cputime.h>
  17 #include <asm/lowcore.h>
  18 #include <asm/irq.h>
  19 #include "entry.h"
  20
  21 struct ext_int_info {
  22         struct ext_int_info *next;
  23         ext_int_handler_t handler;
  24         __u16 code;
  25 };
  26
  27 /*
  28  * ext_int_hash[index] is the start of the list for all external interrupts
  29  * that hash to this index. With the current set of external interrupts
  30  * (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000
  31  * iucv and 0x2603 pfault) this is always the first element.
  32  */
  33 static struct ext_int_info *ext_int_hash[256];
  34
  35 static inline int ext_hash(__u16 code)
  36 {
  37         return (code + (code >> 9)) & 0xff;
  38 }
  39
  40 int register_external_interrupt(__u16 code, ext_int_handler_t handler)
  41 {
  42         struct ext_int_info *p;
  43         int index;
  44
  45         p = kmalloc(sizeof(*p), GFP_ATOMIC);
  46         if (!p)
  47                 return -ENOMEM;
  48         p->code = code;
  49         p->handler = handler;
  50         index = ext_hash(code);
  51         p->next = ext_int_hash[index];
  52         ext_int_hash[index] = p;
  53         return 0;
  54 }
  55 EXPORT_SYMBOL(register_external_interrupt);
  56
  57 int unregister_external_interrupt(__u16 code, ext_int_handler_t handler)
  58 {
  59         struct ext_int_info *p, *q;
  60         int index;
  61
  62         index = ext_hash(code);
  63         q = NULL;
  64         p = ext_int_hash[index];
  65         while (p) {
  66                 if (p->code == code && p->handler == handler)
  67                         break;
  68                 q = p;
  69                 p = p->next;
  70         }
  71         if (!p)
  72                 return -ENOENT;
  73         if (q)
  74                 q->next = p->next;
  75         else
  76                 ext_int_hash[index] = p->next;
  77         kfree(p);
  78         return 0;
  79 }
  80 EXPORT_SYMBOL(unregister_external_interrupt);
  81
  82 void __irq_entry do_extint(struct pt_regs *regs, unsigned int ext_int_code,
  83                            unsigned int param32, unsigned long param64)
  84 {
  85         struct pt_regs *old_regs;
  86         unsigned short code;
  87         struct ext_int_info *p;
  88         int index;
  89
  90         code = (unsigned short) ext_int_code;
  91         old_regs = set_irq_regs(regs);
  92         s390_idle_check(regs, S390_lowcore.int_clock,
  93                         S390_lowcore.async_enter_timer);
  94         irq_enter();
  95         if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
  96                 /* Serve timer interrupts first. */
  97                 clock_comparator_work();
  98         kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
  99         if (code != 0x1004)
 100                 __get_cpu_var(s390_idle).nohz_delay = 1;
 101         index = ext_hash(code);
 102         for (p = ext_int_hash[index]; p; p = p->next) {
 103                 if (likely(p->code == code))
 104                         p->handler(ext_int_code, param32, param64);
 105         }
 106         irq_exit();
 107         set_irq_regs(old_regs);
 108 }