Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 1 | /* |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 2 | * Out of line spinlock code. |
| 3 | * |
Heiko Carstens | a53c8fa | 2012-07-20 11:15:04 +0200 | [diff] [blame] | 4 | * Copyright IBM Corp. 2004, 2006 |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 5 | * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) |
| 6 | */ |
| 7 | |
| 8 | #include <linux/types.h> |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/spinlock.h> |
| 11 | #include <linux/init.h> |
Martin Schwidefsky | 8b646bd | 2012-03-11 11:59:26 -0400 | [diff] [blame] | 12 | #include <linux/smp.h> |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 13 | #include <asm/io.h> |
| 14 | |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 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 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 27 | void arch_spin_lock_wait(arch_spinlock_t *lp) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 28 | { |
| 29 | int count = spin_retry; |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 30 | unsigned int cpu = ~smp_processor_id(); |
Gerald Schaefer | 59b6978 | 2010-02-26 22:37:40 +0100 | [diff] [blame] | 31 | unsigned int owner; |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 32 | |
| 33 | while (1) { |
Gerald Schaefer | 59b6978 | 2010-02-26 22:37:40 +0100 | [diff] [blame] | 34 | owner = lp->owner_cpu; |
| 35 | if (!owner || smp_vcpu_scheduled(~owner)) { |
| 36 | for (count = spin_retry; count > 0; count--) { |
| 37 | if (arch_spin_is_locked(lp)) |
| 38 | continue; |
| 39 | if (_raw_compare_and_swap(&lp->owner_cpu, 0, |
| 40 | cpu) == 0) |
| 41 | return; |
| 42 | } |
| 43 | if (MACHINE_IS_LPAR) |
| 44 | continue; |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 45 | } |
Gerald Schaefer | 59b6978 | 2010-02-26 22:37:40 +0100 | [diff] [blame] | 46 | owner = lp->owner_cpu; |
| 47 | if (owner) |
Martin Schwidefsky | 8b646bd | 2012-03-11 11:59:26 -0400 | [diff] [blame] | 48 | smp_yield_cpu(~owner); |
Heiko Carstens | 3b4beb3 | 2008-01-26 14:11:03 +0100 | [diff] [blame] | 49 | if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 50 | return; |
| 51 | } |
| 52 | } |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 53 | EXPORT_SYMBOL(arch_spin_lock_wait); |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 54 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 55 | void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) |
Hisashi Hifumi | 894cdde | 2008-01-26 14:11:28 +0100 | [diff] [blame] | 56 | { |
| 57 | int count = spin_retry; |
| 58 | unsigned int cpu = ~smp_processor_id(); |
Gerald Schaefer | 59b6978 | 2010-02-26 22:37:40 +0100 | [diff] [blame] | 59 | unsigned int owner; |
Hisashi Hifumi | 894cdde | 2008-01-26 14:11:28 +0100 | [diff] [blame] | 60 | |
| 61 | local_irq_restore(flags); |
| 62 | while (1) { |
Gerald Schaefer | 59b6978 | 2010-02-26 22:37:40 +0100 | [diff] [blame] | 63 | owner = lp->owner_cpu; |
| 64 | if (!owner || smp_vcpu_scheduled(~owner)) { |
| 65 | for (count = spin_retry; count > 0; count--) { |
| 66 | if (arch_spin_is_locked(lp)) |
| 67 | continue; |
| 68 | local_irq_disable(); |
| 69 | if (_raw_compare_and_swap(&lp->owner_cpu, 0, |
| 70 | cpu) == 0) |
| 71 | return; |
| 72 | local_irq_restore(flags); |
| 73 | } |
| 74 | if (MACHINE_IS_LPAR) |
| 75 | continue; |
Hisashi Hifumi | 894cdde | 2008-01-26 14:11:28 +0100 | [diff] [blame] | 76 | } |
Gerald Schaefer | 59b6978 | 2010-02-26 22:37:40 +0100 | [diff] [blame] | 77 | owner = lp->owner_cpu; |
| 78 | if (owner) |
Martin Schwidefsky | 8b646bd | 2012-03-11 11:59:26 -0400 | [diff] [blame] | 79 | smp_yield_cpu(~owner); |
Hisashi Hifumi | 894cdde | 2008-01-26 14:11:28 +0100 | [diff] [blame] | 80 | local_irq_disable(); |
| 81 | if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) |
| 82 | return; |
| 83 | local_irq_restore(flags); |
| 84 | } |
| 85 | } |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 86 | EXPORT_SYMBOL(arch_spin_lock_wait_flags); |
Hisashi Hifumi | 894cdde | 2008-01-26 14:11:28 +0100 | [diff] [blame] | 87 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 88 | int arch_spin_trylock_retry(arch_spinlock_t *lp) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 89 | { |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 90 | unsigned int cpu = ~smp_processor_id(); |
| 91 | int count; |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 92 | |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 93 | for (count = spin_retry; count > 0; count--) { |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 94 | if (arch_spin_is_locked(lp)) |
Christian Ehrhardt | 9656716 | 2006-03-09 17:33:49 -0800 | [diff] [blame] | 95 | continue; |
Heiko Carstens | 3b4beb3 | 2008-01-26 14:11:03 +0100 | [diff] [blame] | 96 | if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 97 | return 1; |
| 98 | } |
| 99 | return 0; |
| 100 | } |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 101 | EXPORT_SYMBOL(arch_spin_trylock_retry); |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 102 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 103 | void arch_spin_relax(arch_spinlock_t *lock) |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 104 | { |
| 105 | unsigned int cpu = lock->owner_cpu; |
Gerald Schaefer | 59b6978 | 2010-02-26 22:37:40 +0100 | [diff] [blame] | 106 | if (cpu != 0) { |
| 107 | if (MACHINE_IS_VM || MACHINE_IS_KVM || |
| 108 | !smp_vcpu_scheduled(~cpu)) |
Martin Schwidefsky | 8b646bd | 2012-03-11 11:59:26 -0400 | [diff] [blame] | 109 | smp_yield_cpu(~cpu); |
Gerald Schaefer | 59b6978 | 2010-02-26 22:37:40 +0100 | [diff] [blame] | 110 | } |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 111 | } |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 112 | EXPORT_SYMBOL(arch_spin_relax); |
Martin Schwidefsky | 3c1fcfe | 2006-09-30 23:27:45 -0700 | [diff] [blame] | 113 | |
Thomas Gleixner | fb3a6bb | 2009-12-03 20:01:19 +0100 | [diff] [blame] | 114 | void _raw_read_lock_wait(arch_rwlock_t *rw) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 115 | { |
| 116 | unsigned int old; |
| 117 | int count = spin_retry; |
| 118 | |
| 119 | while (1) { |
| 120 | if (count-- <= 0) { |
Martin Schwidefsky | 8b646bd | 2012-03-11 11:59:26 -0400 | [diff] [blame] | 121 | smp_yield(); |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 122 | count = spin_retry; |
| 123 | } |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 124 | if (!arch_read_can_lock(rw)) |
Christian Ehrhardt | 9656716 | 2006-03-09 17:33:49 -0800 | [diff] [blame] | 125 | continue; |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 126 | old = rw->lock & 0x7fffffffU; |
| 127 | if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old) |
| 128 | return; |
| 129 | } |
| 130 | } |
| 131 | EXPORT_SYMBOL(_raw_read_lock_wait); |
| 132 | |
Thomas Gleixner | fb3a6bb | 2009-12-03 20:01:19 +0100 | [diff] [blame] | 133 | void _raw_read_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags) |
Heiko Carstens | ce58ae6 | 2009-06-12 10:26:22 +0200 | [diff] [blame] | 134 | { |
| 135 | unsigned int old; |
| 136 | int count = spin_retry; |
| 137 | |
| 138 | local_irq_restore(flags); |
| 139 | while (1) { |
| 140 | if (count-- <= 0) { |
Martin Schwidefsky | 8b646bd | 2012-03-11 11:59:26 -0400 | [diff] [blame] | 141 | smp_yield(); |
Heiko Carstens | ce58ae6 | 2009-06-12 10:26:22 +0200 | [diff] [blame] | 142 | count = spin_retry; |
| 143 | } |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 144 | if (!arch_read_can_lock(rw)) |
Heiko Carstens | ce58ae6 | 2009-06-12 10:26:22 +0200 | [diff] [blame] | 145 | continue; |
| 146 | old = rw->lock & 0x7fffffffU; |
| 147 | local_irq_disable(); |
| 148 | if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old) |
| 149 | return; |
| 150 | } |
| 151 | } |
| 152 | EXPORT_SYMBOL(_raw_read_lock_wait_flags); |
| 153 | |
Thomas Gleixner | fb3a6bb | 2009-12-03 20:01:19 +0100 | [diff] [blame] | 154 | int _raw_read_trylock_retry(arch_rwlock_t *rw) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 155 | { |
| 156 | unsigned int old; |
| 157 | int count = spin_retry; |
| 158 | |
| 159 | while (count-- > 0) { |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 160 | if (!arch_read_can_lock(rw)) |
Christian Ehrhardt | 9656716 | 2006-03-09 17:33:49 -0800 | [diff] [blame] | 161 | continue; |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 162 | old = rw->lock & 0x7fffffffU; |
| 163 | if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old) |
| 164 | return 1; |
| 165 | } |
| 166 | return 0; |
| 167 | } |
| 168 | EXPORT_SYMBOL(_raw_read_trylock_retry); |
| 169 | |
Thomas Gleixner | fb3a6bb | 2009-12-03 20:01:19 +0100 | [diff] [blame] | 170 | void _raw_write_lock_wait(arch_rwlock_t *rw) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 171 | { |
| 172 | int count = spin_retry; |
| 173 | |
| 174 | while (1) { |
| 175 | if (count-- <= 0) { |
Martin Schwidefsky | 8b646bd | 2012-03-11 11:59:26 -0400 | [diff] [blame] | 176 | smp_yield(); |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 177 | count = spin_retry; |
| 178 | } |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 179 | if (!arch_write_can_lock(rw)) |
Christian Ehrhardt | 9656716 | 2006-03-09 17:33:49 -0800 | [diff] [blame] | 180 | continue; |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 181 | if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0) |
| 182 | return; |
| 183 | } |
| 184 | } |
| 185 | EXPORT_SYMBOL(_raw_write_lock_wait); |
| 186 | |
Thomas Gleixner | fb3a6bb | 2009-12-03 20:01:19 +0100 | [diff] [blame] | 187 | void _raw_write_lock_wait_flags(arch_rwlock_t *rw, unsigned long flags) |
Heiko Carstens | ce58ae6 | 2009-06-12 10:26:22 +0200 | [diff] [blame] | 188 | { |
| 189 | int count = spin_retry; |
| 190 | |
| 191 | local_irq_restore(flags); |
| 192 | while (1) { |
| 193 | if (count-- <= 0) { |
Martin Schwidefsky | 8b646bd | 2012-03-11 11:59:26 -0400 | [diff] [blame] | 194 | smp_yield(); |
Heiko Carstens | ce58ae6 | 2009-06-12 10:26:22 +0200 | [diff] [blame] | 195 | count = spin_retry; |
| 196 | } |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 197 | if (!arch_write_can_lock(rw)) |
Heiko Carstens | ce58ae6 | 2009-06-12 10:26:22 +0200 | [diff] [blame] | 198 | continue; |
| 199 | local_irq_disable(); |
| 200 | if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0) |
| 201 | return; |
| 202 | } |
| 203 | } |
| 204 | EXPORT_SYMBOL(_raw_write_lock_wait_flags); |
| 205 | |
Thomas Gleixner | fb3a6bb | 2009-12-03 20:01:19 +0100 | [diff] [blame] | 206 | int _raw_write_trylock_retry(arch_rwlock_t *rw) |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 207 | { |
| 208 | int count = spin_retry; |
| 209 | |
| 210 | while (count-- > 0) { |
Thomas Gleixner | e593194 | 2009-12-03 20:08:46 +0100 | [diff] [blame] | 211 | if (!arch_write_can_lock(rw)) |
Christian Ehrhardt | 9656716 | 2006-03-09 17:33:49 -0800 | [diff] [blame] | 212 | continue; |
Martin Schwidefsky | 951f22d | 2005-07-27 11:44:57 -0700 | [diff] [blame] | 213 | if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0) |
| 214 | return 1; |
| 215 | } |
| 216 | return 0; |
| 217 | } |
| 218 | EXPORT_SYMBOL(_raw_write_trylock_retry); |