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Diffstat (limited to 'arch/tile/include/asm/spinlock_64.h')
-rw-r--r-- | arch/tile/include/asm/spinlock_64.h | 138 |
1 files changed, 0 insertions, 138 deletions
diff --git a/arch/tile/include/asm/spinlock_64.h b/arch/tile/include/asm/spinlock_64.h deleted file mode 100644 index 5b616ef642a8..000000000000 --- a/arch/tile/include/asm/spinlock_64.h +++ /dev/null @@ -1,138 +0,0 @@ -/* - * Copyright 2011 Tilera Corporation. All Rights Reserved. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation, version 2. - * - * This program is distributed in the hope that it will be useful, but - * WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or - * NON INFRINGEMENT. See the GNU General Public License for - * more details. - * - * 64-bit SMP ticket spinlocks, allowing only a single CPU anywhere - * (the type definitions are in asm/spinlock_types.h) - */ - -#ifndef _ASM_TILE_SPINLOCK_64_H -#define _ASM_TILE_SPINLOCK_64_H - -#include <linux/compiler.h> - -/* Shifts and masks for the various fields in "lock". */ -#define __ARCH_SPIN_CURRENT_SHIFT 17 -#define __ARCH_SPIN_NEXT_MASK 0x7fff -#define __ARCH_SPIN_NEXT_OVERFLOW 0x8000 - -/* - * Return the "current" portion of a ticket lock value, - * i.e. the number that currently owns the lock. - */ -static inline u32 arch_spin_current(u32 val) -{ - return val >> __ARCH_SPIN_CURRENT_SHIFT; -} - -/* - * Return the "next" portion of a ticket lock value, - * i.e. the number that the next task to try to acquire the lock will get. - */ -static inline u32 arch_spin_next(u32 val) -{ - return val & __ARCH_SPIN_NEXT_MASK; -} - -/* The lock is locked if a task would have to wait to get it. */ -static inline int arch_spin_is_locked(arch_spinlock_t *lock) -{ - /* Use READ_ONCE() to ensure that calling this in a loop is OK. */ - u32 val = READ_ONCE(lock->lock); - return arch_spin_current(val) != arch_spin_next(val); -} - -/* Bump the current ticket so the next task owns the lock. */ -static inline void arch_spin_unlock(arch_spinlock_t *lock) -{ - wmb(); /* guarantee anything modified under the lock is visible */ - __insn_fetchadd4(&lock->lock, 1U << __ARCH_SPIN_CURRENT_SHIFT); -} - -void arch_spin_lock_slow(arch_spinlock_t *lock, u32 val); - -/* Grab the "next" ticket number and bump it atomically. - * If the current ticket is not ours, go to the slow path. - * We also take the slow path if the "next" value overflows. - */ -static inline void arch_spin_lock(arch_spinlock_t *lock) -{ - u32 val = __insn_fetchadd4(&lock->lock, 1); - u32 ticket = val & (__ARCH_SPIN_NEXT_MASK | __ARCH_SPIN_NEXT_OVERFLOW); - if (unlikely(arch_spin_current(val) != ticket)) - arch_spin_lock_slow(lock, ticket); -} - -/* Try to get the lock, and return whether we succeeded. */ -int arch_spin_trylock(arch_spinlock_t *lock); - -/* - * Read-write spinlocks, allowing multiple readers - * but only one writer. - * - * We use fetchadd() for readers, and fetchor() with the sign bit - * for writers. - */ - -#define __WRITE_LOCK_BIT (1 << 31) - -static inline int arch_write_val_locked(int val) -{ - return val < 0; /* Optimize "val & __WRITE_LOCK_BIT". */ -} - -extern void __read_lock_failed(arch_rwlock_t *rw); - -static inline void arch_read_lock(arch_rwlock_t *rw) -{ - u32 val = __insn_fetchaddgez4(&rw->lock, 1); - if (unlikely(arch_write_val_locked(val))) - __read_lock_failed(rw); -} - -extern void __write_lock_failed(arch_rwlock_t *rw, u32 val); - -static inline void arch_write_lock(arch_rwlock_t *rw) -{ - u32 val = __insn_fetchor4(&rw->lock, __WRITE_LOCK_BIT); - if (unlikely(val != 0)) - __write_lock_failed(rw, val); -} - -static inline void arch_read_unlock(arch_rwlock_t *rw) -{ - __insn_mf(); - __insn_fetchadd4(&rw->lock, -1); -} - -static inline void arch_write_unlock(arch_rwlock_t *rw) -{ - __insn_mf(); - __insn_exch4(&rw->lock, 0); /* Avoid waiting in the write buffer. */ -} - -static inline int arch_read_trylock(arch_rwlock_t *rw) -{ - return !arch_write_val_locked(__insn_fetchaddgez4(&rw->lock, 1)); -} - -static inline int arch_write_trylock(arch_rwlock_t *rw) -{ - u32 val = __insn_fetchor4(&rw->lock, __WRITE_LOCK_BIT); - if (likely(val == 0)) - return 1; - if (!arch_write_val_locked(val)) - __insn_fetchand4(&rw->lock, ~__WRITE_LOCK_BIT); - return 0; -} - -#endif /* _ASM_TILE_SPINLOCK_64_H */ |