Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * include/asm-s390/spinlock.h |
| 3 | * |
| 4 | * S390 version |
| 5 | * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation |
| 6 | * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) |
| 7 | * |
| 8 | * Derived from "include/asm-i386/spinlock.h" |
| 9 | */ |
| 10 | |
| 11 | #ifndef __ASM_SPINLOCK_H |
| 12 | #define __ASM_SPINLOCK_H |
| 13 | |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 14 | #include <linux/smp.h> |
| 15 | |
Martin Schwidefsky | 638ad34 | 2011-10-30 15:17:13 +0100 | [diff] [blame] | 16 | extern int spin_retry; |
| 17 | |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 18 | static inline int |
| 19 | _raw_compare_and_swap(volatile unsigned int *lock, |
| 20 | unsigned int old, unsigned int new) |
| 21 | { |
Martin Schwidefsky | 94c12cc | 2006-09-28 16:56:43 +0200 | [diff] [blame] | 22 | asm volatile( |
| 23 | " cs %0,%3,%1" |
| 24 | : "=d" (old), "=Q" (*lock) |
| 25 | : "0" (old), "d" (new), "Q" (*lock) |
| 26 | : "cc", "memory" ); |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 27 | return old; |
| 28 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | |
| 30 | /* |
| 31 | * Simple spin lock operations. There are two variants, one clears IRQ's |
| 32 | * on the local processor, one does not. |
| 33 | * |
| 34 | * We make no fairness assumptions. They have a cost. |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 35 | * |
| 36 | * (the type definitions are in asm/spinlock_types.h) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | */ |
| 38 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 39 | #define arch_spin_is_locked(x) ((x)->owner_cpu != 0) |
| 40 | #define arch_spin_unlock_wait(lock) \ |
| 41 | do { while (arch_spin_is_locked(lock)) \ |
| 42 | arch_spin_relax(lock); } while (0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 44 | extern void arch_spin_lock_wait(arch_spinlock_t *); |
| 45 | extern void arch_spin_lock_wait_flags(arch_spinlock_t *, unsigned long flags); |
| 46 | extern int arch_spin_trylock_retry(arch_spinlock_t *); |
| 47 | extern void arch_spin_relax(arch_spinlock_t *lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 49 | static inline void arch_spin_lock(arch_spinlock_t *lp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | { |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 51 | int old; |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 52 | |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 53 | old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id()); |
Heiko Carstens | 3b4beb3 | 2008-01-26 14:11:03 +0100 | [diff] [blame] | 54 | if (likely(old == 0)) |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 55 | return; |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 56 | arch_spin_lock_wait(lp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | } |
| 58 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 59 | static inline void arch_spin_lock_flags(arch_spinlock_t *lp, |
Hisashi Hifumi | 894cdde | 2008-01-26 14:11:28 +0100 | [diff] [blame] | 60 | unsigned long flags) |
| 61 | { |
| 62 | int old; |
| 63 | |
| 64 | old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id()); |
| 65 | if (likely(old == 0)) |
| 66 | return; |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 67 | arch_spin_lock_wait_flags(lp, flags); |
Hisashi Hifumi | 894cdde | 2008-01-26 14:11:28 +0100 | [diff] [blame] | 68 | } |
| 69 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 70 | static inline int arch_spin_trylock(arch_spinlock_t *lp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 71 | { |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 72 | int old; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 74 | old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id()); |
Heiko Carstens | 3b4beb3 | 2008-01-26 14:11:03 +0100 | [diff] [blame] | 75 | if (likely(old == 0)) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 76 | return 1; |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 77 | return arch_spin_trylock_retry(lp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | } |
| 79 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 80 | static inline void arch_spin_unlock(arch_spinlock_t *lp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | { |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 82 | _raw_compare_and_swap(&lp->owner_cpu, lp->owner_cpu, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | } |
| 84 | |
| 85 | /* |
| 86 | * Read-write spinlocks, allowing multiple readers |
| 87 | * but only one writer. |
| 88 | * |
| 89 | * NOTE! it is quite common to have readers in interrupts |
| 90 | * but no interrupt writers. For those circumstances we |
| 91 | * can "mix" irq-safe locks - any writer needs to get a |
| 92 | * irq-safe write-lock, but readers can get non-irqsafe |
| 93 | * read-locks. |
| 94 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | |
| 96 | /** |
| 97 | * read_can_lock - would read_trylock() succeed? |
| 98 | * @lock: the rwlock in question. |
| 99 | */ |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 100 | #define arch_read_can_lock(x) ((int)(x)->lock >= 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | |
| 102 | /** |
| 103 | * write_can_lock - would write_trylock() succeed? |
| 104 | * @lock: the rwlock in question. |
| 105 | */ |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 106 | #define arch_write_can_lock(x) ((x)->lock == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | |
Thomas Gleixner | fb3a6bb | 2009-12-03 20:01:19 +0100 | [diff] [blame] | 108 | extern void _raw_read_lock_wait(arch_rwlock_t *lp); |
| 109 | extern void _raw_read_lock_wait_flags(arch_rwlock_t *lp, unsigned long flags); |
| 110 | extern int _raw_read_trylock_retry(arch_rwlock_t *lp); |
| 111 | extern void _raw_write_lock_wait(arch_rwlock_t *lp); |
| 112 | extern void _raw_write_lock_wait_flags(arch_rwlock_t *lp, unsigned long flags); |
| 113 | extern int _raw_write_trylock_retry(arch_rwlock_t *lp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 115 | static inline void arch_read_lock(arch_rwlock_t *rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | { |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 117 | unsigned int old; |
| 118 | old = rw->lock & 0x7fffffffU; |
| 119 | if (_raw_compare_and_swap(&rw->lock, old, old + 1) != old) |
| 120 | _raw_read_lock_wait(rw); |
| 121 | } |
| 122 | |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 123 | static inline void arch_read_lock_flags(arch_rwlock_t *rw, unsigned long flags) |
Heiko Carstens | ce58ae6 | 2009-06-12 10:26:22 +0200 | [diff] [blame] | 124 | { |
| 125 | unsigned int old; |
| 126 | old = rw->lock & 0x7fffffffU; |
| 127 | if (_raw_compare_and_swap(&rw->lock, old, old + 1) != old) |
| 128 | _raw_read_lock_wait_flags(rw, flags); |
| 129 | } |
| 130 | |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 131 | static inline void arch_read_unlock(arch_rwlock_t *rw) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 132 | { |
| 133 | unsigned int old, cmp; |
| 134 | |
| 135 | old = rw->lock; |
| 136 | do { |
| 137 | cmp = old; |
| 138 | old = _raw_compare_and_swap(&rw->lock, old, old - 1); |
| 139 | } while (cmp != old); |
| 140 | } |
| 141 | |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 142 | static inline void arch_write_lock(arch_rwlock_t *rw) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 143 | { |
| 144 | if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0)) |
| 145 | _raw_write_lock_wait(rw); |
| 146 | } |
| 147 | |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 148 | static inline void arch_write_lock_flags(arch_rwlock_t *rw, unsigned long flags) |
Heiko Carstens | ce58ae6 | 2009-06-12 10:26:22 +0200 | [diff] [blame] | 149 | { |
| 150 | if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0)) |
| 151 | _raw_write_lock_wait_flags(rw, flags); |
| 152 | } |
| 153 | |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 154 | static inline void arch_write_unlock(arch_rwlock_t *rw) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 155 | { |
| 156 | _raw_compare_and_swap(&rw->lock, 0x80000000, 0); |
| 157 | } |
| 158 | |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 159 | static inline int arch_read_trylock(arch_rwlock_t *rw) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 160 | { |
| 161 | unsigned int old; |
| 162 | old = rw->lock & 0x7fffffffU; |
| 163 | if (likely(_raw_compare_and_swap(&rw->lock, old, old + 1) == old)) |
| 164 | return 1; |
| 165 | return _raw_read_trylock_retry(rw); |
| 166 | } |
| 167 | |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 168 | static inline int arch_write_trylock(arch_rwlock_t *rw) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 169 | { |
| 170 | if (likely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0)) |
| 171 | return 1; |
| 172 | return _raw_write_trylock_retry(rw); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | } |
| 174 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 175 | #define arch_read_relax(lock) cpu_relax() |
| 176 | #define arch_write_relax(lock) cpu_relax() |
Martin Schwidefsky | ef6edc9 | 2006-09-30 23:27:43 -0700 | [diff] [blame] | 177 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | #endif /* __ASM_SPINLOCK_H */ |