From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- arch/s390/include/asm/spinlock.h | 148 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 148 insertions(+) create mode 100644 arch/s390/include/asm/spinlock.h (limited to 'arch/s390/include/asm/spinlock.h') diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h new file mode 100644 index 000000000..37127cd77 --- /dev/null +++ b/arch/s390/include/asm/spinlock.h @@ -0,0 +1,148 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * S390 version + * Copyright IBM Corp. 1999 + * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) + * + * Derived from "include/asm-i386/spinlock.h" + */ + +#ifndef __ASM_SPINLOCK_H +#define __ASM_SPINLOCK_H + +#include +#include +#include +#include +#include + +#define SPINLOCK_LOCKVAL (S390_lowcore.spinlock_lockval) + +extern int spin_retry; + +bool arch_vcpu_is_preempted(int cpu); + +#define vcpu_is_preempted arch_vcpu_is_preempted + +/* + * Simple spin lock operations. There are two variants, one clears IRQ's + * on the local processor, one does not. + * + * We make no fairness assumptions. They have a cost. + * + * (the type definitions are in asm/spinlock_types.h) + */ + +void arch_spin_relax(arch_spinlock_t *lock); +#define arch_spin_relax arch_spin_relax + +void arch_spin_lock_wait(arch_spinlock_t *); +int arch_spin_trylock_retry(arch_spinlock_t *); +void arch_spin_lock_setup(int cpu); + +static inline u32 arch_spin_lockval(int cpu) +{ + return cpu + 1; +} + +static inline int arch_spin_value_unlocked(arch_spinlock_t lock) +{ + return lock.lock == 0; +} + +static inline int arch_spin_is_locked(arch_spinlock_t *lp) +{ + return READ_ONCE(lp->lock) != 0; +} + +static inline int arch_spin_trylock_once(arch_spinlock_t *lp) +{ + barrier(); + return likely(__atomic_cmpxchg_bool(&lp->lock, 0, SPINLOCK_LOCKVAL)); +} + +static inline void arch_spin_lock(arch_spinlock_t *lp) +{ + if (!arch_spin_trylock_once(lp)) + arch_spin_lock_wait(lp); +} + +static inline int arch_spin_trylock(arch_spinlock_t *lp) +{ + if (!arch_spin_trylock_once(lp)) + return arch_spin_trylock_retry(lp); + return 1; +} + +static inline void arch_spin_unlock(arch_spinlock_t *lp) +{ + typecheck(int, lp->lock); + kcsan_release(); + asm_inline volatile( + ALTERNATIVE("nop", ".insn rre,0xb2fa0000,7,0", 49) /* NIAI 7 */ + " sth %1,%0\n" + : "=R" (((unsigned short *) &lp->lock)[1]) + : "d" (0) : "cc", "memory"); +} + +/* + * Read-write spinlocks, allowing multiple readers + * but only one writer. + * + * NOTE! it is quite common to have readers in interrupts + * but no interrupt writers. For those circumstances we + * can "mix" irq-safe locks - any writer needs to get a + * irq-safe write-lock, but readers can get non-irqsafe + * read-locks. + */ + +#define arch_read_relax(rw) barrier() +#define arch_write_relax(rw) barrier() + +void arch_read_lock_wait(arch_rwlock_t *lp); +void arch_write_lock_wait(arch_rwlock_t *lp); + +static inline void arch_read_lock(arch_rwlock_t *rw) +{ + int old; + + old = __atomic_add(1, &rw->cnts); + if (old & 0xffff0000) + arch_read_lock_wait(rw); +} + +static inline void arch_read_unlock(arch_rwlock_t *rw) +{ + __atomic_add_const_barrier(-1, &rw->cnts); +} + +static inline void arch_write_lock(arch_rwlock_t *rw) +{ + if (!__atomic_cmpxchg_bool(&rw->cnts, 0, 0x30000)) + arch_write_lock_wait(rw); +} + +static inline void arch_write_unlock(arch_rwlock_t *rw) +{ + __atomic_add_barrier(-0x30000, &rw->cnts); +} + + +static inline int arch_read_trylock(arch_rwlock_t *rw) +{ + int old; + + old = READ_ONCE(rw->cnts); + return (!(old & 0xffff0000) && + __atomic_cmpxchg_bool(&rw->cnts, old, old + 1)); +} + +static inline int arch_write_trylock(arch_rwlock_t *rw) +{ + int old; + + old = READ_ONCE(rw->cnts); + return !old && __atomic_cmpxchg_bool(&rw->cnts, 0, 0x30000); +} + +#endif /* __ASM_SPINLOCK_H */ -- cgit v1.2.3