/* * arch/s390/lib/spinlock.c * Out of line spinlock code. * * Copyright (C) IBM Corp. 2004, 2006 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) */ #include <linux/types.h> #include <linux/module.h> #include <linux/spinlock.h> #include <linux/init.h> #include <asm/io.h> int spin_retry = 1000; /** * spin_retry= parameter */ static int __init spin_retry_setup(char *str) { spin_retry = simple_strtoul(str, &str, 0); return 1; } __setup("spin_retry=", spin_retry_setup); static inline void _raw_yield(void) { if (MACHINE_HAS_DIAG44) asm volatile("diag 0,0,0x44"); } static inline void _raw_yield_cpu(int cpu) { if (MACHINE_HAS_DIAG9C) asm volatile("diag %0,0,0x9c" : : "d" (__cpu_logical_map[cpu])); else _raw_yield(); } void _raw_spin_lock_wait(raw_spinlock_t *lp, unsigned int pc) { int count = spin_retry; unsigned int cpu = ~smp_processor_id(); while (1) { if (count-- <= 0) { unsigned int owner = lp->owner_cpu; if (owner != 0) _raw_yield_cpu(~owner); count = spin_retry; } if (__raw_spin_is_locked(lp)) continue; if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) { lp->owner_pc = pc; return; } } } EXPORT_SYMBOL(_raw_spin_lock_wait); int _raw_spin_trylock_retry(raw_spinlock_t *lp, unsigned int pc) { unsigned int cpu = ~smp_processor_id(); int count; for (count = spin_retry; count > 0; count--) { if (__raw_spin_is_locked(lp)) continue; if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0) { lp->owner_pc = pc; return 1; } } return 0; } EXPORT_SYMBOL(_raw_spin_trylock_retry); void _raw_spin_relax(raw_spinlock_t *lock) { unsigned int cpu = lock->owner_cpu; if (cpu != 0) _raw_yield_cpu(~cpu); } EXPORT_SYMBOL(_raw_spin_relax); void _raw_read_lock_wait(raw_rwlock_t *rw) { unsigned int old; int count = spin_retry; while (1) { if (count-- <= 0) { _raw_yield(); count = spin_retry; } if (!__raw_read_can_lock(rw)) continue; old = rw->lock & 0x7fffffffU; if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old) return; } } EXPORT_SYMBOL(_raw_read_lock_wait); int _raw_read_trylock_retry(raw_rwlock_t *rw) { unsigned int old; int count = spin_retry; while (count-- > 0) { if (!__raw_read_can_lock(rw)) continue; old = rw->lock & 0x7fffffffU; if (_raw_compare_and_swap(&rw->lock, old, old + 1) == old) return 1; } return 0; } EXPORT_SYMBOL(_raw_read_trylock_retry); void _raw_write_lock_wait(raw_rwlock_t *rw) { int count = spin_retry; while (1) { if (count-- <= 0) { _raw_yield(); count = spin_retry; } if (!__raw_write_can_lock(rw)) continue; if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0) return; } } EXPORT_SYMBOL(_raw_write_lock_wait); int _raw_write_trylock_retry(raw_rwlock_t *rw) { int count = spin_retry; while (count-- > 0) { if (!__raw_write_can_lock(rw)) continue; if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0) return 1; } return 0; } EXPORT_SYMBOL(_raw_write_trylock_retry);