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 atomic_t spin_retry_counter; 17 int spin_retry = 1000; 18 19 /** 20 * spin_retry= parameter 21 */ 22 static int __init spin_retry_setup(char *str) 23 { 24 spin_retry = simple_strtoul(str, &str, 0); 25 return 1; 26 } 27 __setup("spin_retry=", spin_retry_setup); 28 29 static inline void 30 _diag44(void) 31 { 32 #ifdef CONFIG_64BIT 33 if (MACHINE_HAS_DIAG44) 34 #endif 35 asm volatile("diag 0,0,0x44"); 36 } 37 38 void 39 _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc) 40 { 41 int count = spin_retry; 42 43 while (1) { 44 if (count-- <= 0) { 45 _diag44(); 46 count = spin_retry; 47 } 48 atomic_inc(&spin_retry_counter); 49 if (_raw_compare_and_swap(&lp->lock, 0, pc) == 0) 50 return; 51 } 52 } 53 EXPORT_SYMBOL(_raw_spin_lock_wait); 54 55 int 56 _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc) 57 { 58 int count = spin_retry; 59 60 while (count-- > 0) { 61 atomic_inc(&spin_retry_counter); 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 atomic_inc(&spin_retry_counter); 81 old = rw->lock & 0x7fffffffU; 82 if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old) 83 return; 84 } 85 } 86 EXPORT_SYMBOL(_raw_read_lock_wait); 87 88 int 89 _raw_read_trylock_retry(raw_rwlock_t *rw) 90 { 91 unsigned int old; 92 int count = spin_retry; 93 94 while (count-- > 0) { 95 atomic_inc(&spin_retry_counter); 96 old = rw->lock & 0x7fffffffU; 97 if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old) 98 return 1; 99 } 100 return 0; 101 } 102 EXPORT_SYMBOL(_raw_read_trylock_retry); 103 104 void 105 _raw_write_lock_wait(raw_rwlock_t *rw) 106 { 107 int count = spin_retry; 108 109 while (1) { 110 if (count-- <= 0) { 111 _diag44(); 112 count = spin_retry; 113 } 114 atomic_inc(&spin_retry_counter); 115 if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0) 116 return; 117 } 118 } 119 EXPORT_SYMBOL(_raw_write_lock_wait); 120 121 int 122 _raw_write_trylock_retry(raw_rwlock_t *rw) 123 { 124 int count = spin_retry; 125 126 while (count-- > 0) { 127 atomic_inc(&spin_retry_counter); 128 if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0) 129 return 1; 130 } 131 return 0; 132 } 133 EXPORT_SYMBOL(_raw_write_trylock_retry); 134