diff options
author | 2015-08-04 12:17:53 -0700 | |
---|---|---|
committer | 2015-08-04 15:44:42 -0700 | |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/s390/lib/spinlock.c | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/s390/lib/spinlock.c')
-rw-r--r-- | kernel/arch/s390/lib/spinlock.c | 272 |
1 files changed, 272 insertions, 0 deletions
diff --git a/kernel/arch/s390/lib/spinlock.c b/kernel/arch/s390/lib/spinlock.c new file mode 100644 index 000000000..d6c9991f7 --- /dev/null +++ b/kernel/arch/s390/lib/spinlock.c @@ -0,0 +1,272 @@ +/* + * Out of line spinlock code. + * + * Copyright 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 <linux/smp.h> +#include <asm/io.h> + +int spin_retry = -1; + +static int __init spin_retry_init(void) +{ + if (spin_retry < 0) + spin_retry = MACHINE_HAS_CAD ? 10 : 1000; + return 0; +} +early_initcall(spin_retry_init); + +/** + * 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_compare_and_delay(unsigned int *lock, unsigned int old) +{ + asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock)); +} + +void arch_spin_lock_wait(arch_spinlock_t *lp) +{ + unsigned int cpu = SPINLOCK_LOCKVAL; + unsigned int owner; + int count; + + while (1) { + owner = ACCESS_ONCE(lp->lock); + /* Try to get the lock if it is free. */ + if (!owner) { + if (_raw_compare_and_swap(&lp->lock, 0, cpu)) + return; + continue; + } + /* Check if the lock owner is running. */ + if (!smp_vcpu_scheduled(~owner)) { + smp_yield_cpu(~owner); + continue; + } + /* Loop for a while on the lock value. */ + count = spin_retry; + do { + if (MACHINE_HAS_CAD) + _raw_compare_and_delay(&lp->lock, owner); + owner = ACCESS_ONCE(lp->lock); + } while (owner && count-- > 0); + if (!owner) + continue; + /* + * For multiple layers of hypervisors, e.g. z/VM + LPAR + * yield the CPU if the lock is still unavailable. + */ + if (!MACHINE_IS_LPAR) + smp_yield_cpu(~owner); + } +} +EXPORT_SYMBOL(arch_spin_lock_wait); + +void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) +{ + unsigned int cpu = SPINLOCK_LOCKVAL; + unsigned int owner; + int count; + + local_irq_restore(flags); + while (1) { + owner = ACCESS_ONCE(lp->lock); + /* Try to get the lock if it is free. */ + if (!owner) { + local_irq_disable(); + if (_raw_compare_and_swap(&lp->lock, 0, cpu)) + return; + local_irq_restore(flags); + } + /* Check if the lock owner is running. */ + if (!smp_vcpu_scheduled(~owner)) { + smp_yield_cpu(~owner); + continue; + } + /* Loop for a while on the lock value. */ + count = spin_retry; + do { + if (MACHINE_HAS_CAD) + _raw_compare_and_delay(&lp->lock, owner); + owner = ACCESS_ONCE(lp->lock); + } while (owner && count-- > 0); + if (!owner) + continue; + /* + * For multiple layers of hypervisors, e.g. z/VM + LPAR + * yield the CPU if the lock is still unavailable. + */ + if (!MACHINE_IS_LPAR) + smp_yield_cpu(~owner); + } +} +EXPORT_SYMBOL(arch_spin_lock_wait_flags); + +int arch_spin_trylock_retry(arch_spinlock_t *lp) +{ + unsigned int cpu = SPINLOCK_LOCKVAL; + unsigned int owner; + int count; + + for (count = spin_retry; count > 0; count--) { + owner = ACCESS_ONCE(lp->lock); + /* Try to get the lock if it is free. */ + if (!owner) { + if (_raw_compare_and_swap(&lp->lock, 0, cpu)) + return 1; + } else if (MACHINE_HAS_CAD) + _raw_compare_and_delay(&lp->lock, owner); + } + return 0; +} +EXPORT_SYMBOL(arch_spin_trylock_retry); + +void _raw_read_lock_wait(arch_rwlock_t *rw) +{ + unsigned int owner, old; + int count = spin_retry; + +#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES + __RAW_LOCK(&rw->lock, -1, __RAW_OP_ADD); +#endif + owner = 0; + while (1) { + if (count-- <= 0) { + if (owner && !smp_vcpu_scheduled(~owner)) + smp_yield_cpu(~owner); + count = spin_retry; + } + old = ACCESS_ONCE(rw->lock); + owner = ACCESS_ONCE(rw->owner); + if ((int) old < 0) { + if (MACHINE_HAS_CAD) + _raw_compare_and_delay(&rw->lock, old); + continue; + } + if (_raw_compare_and_swap(&rw->lock, old, old + 1)) + return; + } +} +EXPORT_SYMBOL(_raw_read_lock_wait); + +int _raw_read_trylock_retry(arch_rwlock_t *rw) +{ + unsigned int old; + int count = spin_retry; + + while (count-- > 0) { + old = ACCESS_ONCE(rw->lock); + if ((int) old < 0) { + if (MACHINE_HAS_CAD) + _raw_compare_and_delay(&rw->lock, old); + continue; + } + if (_raw_compare_and_swap(&rw->lock, old, old + 1)) + return 1; + } + return 0; +} +EXPORT_SYMBOL(_raw_read_trylock_retry); + +#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES + +void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev) +{ + unsigned int owner, old; + int count = spin_retry; + + owner = 0; + while (1) { + if (count-- <= 0) { + if (owner && !smp_vcpu_scheduled(~owner)) + smp_yield_cpu(~owner); + count = spin_retry; + } + old = ACCESS_ONCE(rw->lock); + owner = ACCESS_ONCE(rw->owner); + smp_rmb(); + if ((int) old >= 0) { + prev = __RAW_LOCK(&rw->lock, 0x80000000, __RAW_OP_OR); + old = prev; + } + if ((old & 0x7fffffff) == 0 && (int) prev >= 0) + break; + if (MACHINE_HAS_CAD) + _raw_compare_and_delay(&rw->lock, old); + } +} +EXPORT_SYMBOL(_raw_write_lock_wait); + +#else /* CONFIG_HAVE_MARCH_Z196_FEATURES */ + +void _raw_write_lock_wait(arch_rwlock_t *rw) +{ + unsigned int owner, old, prev; + int count = spin_retry; + + prev = 0x80000000; + owner = 0; + while (1) { + if (count-- <= 0) { + if (owner && !smp_vcpu_scheduled(~owner)) + smp_yield_cpu(~owner); + count = spin_retry; + } + old = ACCESS_ONCE(rw->lock); + owner = ACCESS_ONCE(rw->owner); + if ((int) old >= 0 && + _raw_compare_and_swap(&rw->lock, old, old | 0x80000000)) + prev = old; + else + smp_rmb(); + if ((old & 0x7fffffff) == 0 && (int) prev >= 0) + break; + if (MACHINE_HAS_CAD) + _raw_compare_and_delay(&rw->lock, old); + } +} +EXPORT_SYMBOL(_raw_write_lock_wait); + +#endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */ + +int _raw_write_trylock_retry(arch_rwlock_t *rw) +{ + unsigned int old; + int count = spin_retry; + + while (count-- > 0) { + old = ACCESS_ONCE(rw->lock); + if (old) { + if (MACHINE_HAS_CAD) + _raw_compare_and_delay(&rw->lock, old); + continue; + } + if (_raw_compare_and_swap(&rw->lock, 0, 0x80000000)) + return 1; + } + return 0; +} +EXPORT_SYMBOL(_raw_write_trylock_retry); + +void arch_lock_relax(unsigned int cpu) +{ + if (!cpu) + return; + if (MACHINE_IS_LPAR && smp_vcpu_scheduled(~cpu)) + return; + smp_yield_cpu(~cpu); +} +EXPORT_SYMBOL(arch_lock_relax); |