diff options
Diffstat (limited to 'arch/tile/lib/spinlock_64.c')
-rw-r--r-- | arch/tile/lib/spinlock_64.c | 97 |
1 files changed, 0 insertions, 97 deletions
diff --git a/arch/tile/lib/spinlock_64.c b/arch/tile/lib/spinlock_64.c deleted file mode 100644 index de414c22892f..000000000000 --- a/arch/tile/lib/spinlock_64.c +++ /dev/null @@ -1,97 +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. - */ - -#include <linux/spinlock.h> -#include <linux/module.h> -#include <asm/processor.h> - -#include "spinlock_common.h" - -/* - * Read the spinlock value without allocating in our cache and without - * causing an invalidation to another cpu with a copy of the cacheline. - * This is important when we are spinning waiting for the lock. - */ -static inline u32 arch_spin_read_noalloc(void *lock) -{ - return atomic_cmpxchg((atomic_t *)lock, -1, -1); -} - -/* - * Wait until the high bits (current) match my ticket. - * If we notice the overflow bit set on entry, we clear it. - */ -void arch_spin_lock_slow(arch_spinlock_t *lock, u32 my_ticket) -{ - if (unlikely(my_ticket & __ARCH_SPIN_NEXT_OVERFLOW)) { - __insn_fetchand4(&lock->lock, ~__ARCH_SPIN_NEXT_OVERFLOW); - my_ticket &= ~__ARCH_SPIN_NEXT_OVERFLOW; - } - - for (;;) { - u32 val = arch_spin_read_noalloc(lock); - u32 delta = my_ticket - arch_spin_current(val); - if (delta == 0) - return; - relax((128 / CYCLES_PER_RELAX_LOOP) * delta); - } -} -EXPORT_SYMBOL(arch_spin_lock_slow); - -/* - * Check the lock to see if it is plausible, and try to get it with cmpxchg(). - */ -int arch_spin_trylock(arch_spinlock_t *lock) -{ - u32 val = arch_spin_read_noalloc(lock); - if (unlikely(arch_spin_current(val) != arch_spin_next(val))) - return 0; - return cmpxchg(&lock->lock, val, (val + 1) & ~__ARCH_SPIN_NEXT_OVERFLOW) - == val; -} -EXPORT_SYMBOL(arch_spin_trylock); - - -/* - * If the read lock fails due to a writer, we retry periodically - * until the value is positive and we write our incremented reader count. - */ -void __read_lock_failed(arch_rwlock_t *rw) -{ - u32 val; - int iterations = 0; - do { - delay_backoff(iterations++); - val = __insn_fetchaddgez4(&rw->lock, 1); - } while (unlikely(arch_write_val_locked(val))); -} -EXPORT_SYMBOL(__read_lock_failed); - -/* - * If we failed because there were readers, clear the "writer" bit - * so we don't block additional readers. Otherwise, there was another - * writer anyway, so our "fetchor" made no difference. Then wait, - * issuing periodic fetchor instructions, till we get the lock. - */ -void __write_lock_failed(arch_rwlock_t *rw, u32 val) -{ - int iterations = 0; - do { - if (!arch_write_val_locked(val)) - val = __insn_fetchand4(&rw->lock, ~__WRITE_LOCK_BIT); - delay_backoff(iterations++); - val = __insn_fetchor4(&rw->lock, __WRITE_LOCK_BIT); - } while (val != 0); -} -EXPORT_SYMBOL(__write_lock_failed); |