1 /* 2 * arch/s390/lib/spinlock.c 3 * Out of line spinlock code. 4 * 5 * Copyright (C) IBM Corp. 2004, 2006 6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) 7 */ 8 9 #include <linux/types.h> 10 #include <linux/module.h> 11 #include <linux/spinlock.h> 12 #include <linux/init.h> 13 #include <asm/io.h> 14 15 int spin_retry = 1000; 16 17 /** 18 * spin_retry= parameter 19 */ 20 static int __init spin_retry_setup(char *str) 21 { 22 spin_retry = simple_strtoul(str, &str, 0); 23 return 1; 24 } 25 __setup("spin_retry=", spin_retry_setup); 26 27 static inline void 28 _diag44(void) 29 { 30 #ifdef CONFIG_64BIT 31 if (MACHINE_HAS_DIAG44) 32 #endif 33 asm volatile("diag 0,0,0x44"); 34 } 35 36 void 37 _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc) 38 { 39 int count = spin_retry; 40 41 while (1) { 42 if (count-- <= 0) { 43 _diag44(); 44 count = spin_retry; 45 } 46 if (__raw_spin_is_locked(lp)) 47 continue; 48 if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0) 49 return; 50 } 51 } 52 EXPORT_SYMBOL(_raw_spin_lock_wait); 53 54 int 55 _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc) 56 { 57 int count = spin_retry; 58 59 while (count-- > 0) { 60 if (__raw_spin_is_locked(lp)) 61 continue; 62 if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0) 63 return 1; 64 } 65 return 0; 66 } 67 EXPORT_SYMBOL(_raw_spin_trylock_retry); 68 69 void 70 _raw_read_lock_wait(raw_rwlock_t *rw) 71 { 72 unsigned int old; 73 int count = spin_retry; 74 75 while (1) { 76 if (count-- <= 0) { 77 _diag44(); 78 count = spin_retry; 79 } 80 if (!__raw_read_can_lock(rw)) 81 continue; 82 old = rw->lock & 0x7fffffffU; 83 if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old) 84 return; 85 } 86 } 87 EXPORT_SYMBOL(_raw_read_lock_wait); 88 89 int 90 _raw_read_trylock_retry(raw_rwlock_t *rw) 91 { 92 unsigned int old; 93 int count = spin_retry; 94 95 while (count-- > 0) { 96 if (!__raw_read_can_lock(rw)) 97 continue; 98 old = rw->lock & 0x7fffffffU; 99 if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old) 100 return 1; 101 } 102 return 0; 103 } 104 EXPORT_SYMBOL(_raw_read_trylock_retry); 105 106 void 107 _raw_write_lock_wait(raw_rwlock_t *rw) 108 { 109 int count = spin_retry; 110 111 while (1) { 112 if (count-- <= 0) { 113 _diag44(); 114 count = spin_retry; 115 } 116 if (!__raw_write_can_lock(rw)) 117 continue; 118 if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0) 119 return; 120 } 121 } 122 EXPORT_SYMBOL(_raw_write_lock_wait); 123 124 int 125 _raw_write_trylock_retry(raw_rwlock_t *rw) 126 { 127 int count = spin_retry; 128 129 while (count-- > 0) { 130 if (!__raw_write_can_lock(rw)) 131 continue; 132 if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0) 133 return 1; 134 } 135 return 0; 136 } 137 EXPORT_SYMBOL(_raw_write_trylock_retry); 138