arch/s390/lib/spinlock.c

   1 /*
   2  *  arch/s390/lib/spinlock.c
   3  *    Out of line spinlock code.
   4  *
   5  *  S390 version
   6  *    Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
   7  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
   8  */
   9
  10 #include <linux/types.h>
  11 #include <linux/module.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/init.h>
  14 #include <asm/io.h>
  15
  16 int spin_retry = 1000;
  17
  18 /**
  19  * spin_retry= parameter
  20  */
  21 static int __init spin_retry_setup(char *str)
  22 {
  23         spin_retry = simple_strtoul(str, &str, 0);
  24         return 1;
  25 }
  26 __setup("spin_retry=", spin_retry_setup);
  27
  28 static inline void
  29 _diag44(void)
  30 {
  31 #ifdef CONFIG_64BIT
  32         if (MACHINE_HAS_DIAG44)
  33 #endif
  34                 asm volatile("diag 0,0,0x44");
  35 }
  36
  37 void
  38 _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc)
  39 {
  40         int count = spin_retry;
  41
  42         while (1) {
  43                 if (count-- <= 0) {
  44                         _diag44();
  45                         count = spin_retry;
  46                 }
  47                 if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0)
  48                         return;
  49         }
  50 }
  51 EXPORT_SYMBOL(_raw_spin_lock_wait);
  52
  53 int
  54 _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc)
  55 {
  56         int count = spin_retry;
  57
  58         while (count-- > 0) {
  59                 if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0)
  60                         return 1;
  61         }
  62         return 0;
  63 }
  64 EXPORT_SYMBOL(_raw_spin_trylock_retry);
  65
  66 void
  67 _raw_read_lock_wait(raw_rwlock_t *rw)
  68 {
  69         unsigned int old;
  70         int count = spin_retry;
  71
  72         while (1) {
  73                 if (count-- <= 0) {
  74                         _diag44();
  75                         count = spin_retry;
  76                 }
  77                 old = rw->lock & 0x7fffffffU;
  78                 if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
  79                         return;
  80         }
  81 }
  82 EXPORT_SYMBOL(_raw_read_lock_wait);
  83
  84 int
  85 _raw_read_trylock_retry(raw_rwlock_t *rw)
  86 {
  87         unsigned int old;
  88         int count = spin_retry;
  89
  90         while (count-- > 0) {
  91                 old = rw->lock & 0x7fffffffU;
  92                 if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old)
  93                         return 1;
  94         }
  95         return 0;
  96 }
  97 EXPORT_SYMBOL(_raw_read_trylock_retry);
  98
  99 void
 100 _raw_write_lock_wait(raw_rwlock_t *rw)
 101 {
 102         int count = spin_retry;
 103
 104         while (1) {
 105                 if (count-- <= 0) {
 106                         _diag44();
 107                         count = spin_retry;
 108                 }
 109                 if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
 110                         return;
 111         }
 112 }
 113 EXPORT_SYMBOL(_raw_write_lock_wait);
 114
 115 int
 116 _raw_write_trylock_retry(raw_rwlock_t *rw)
 117 {
 118         int count = spin_retry;
 119
 120         while (count-- > 0) {
 121                 if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)
 122                         return 1;
 123         }
 124         return 0;
 125 }
 126 EXPORT_SYMBOL(_raw_write_trylock_retry);