/* * Copyright 2010 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. * * 32-bit SMP spinlocks. */ #ifndef _ASM_TILE_SPINLOCK_32_H #define _ASM_TILE_SPINLOCK_32_H #include <linux/atomic.h> #include <asm/page.h> #include <linux/compiler.h> /* * We only use even ticket numbers so the '1' inserted by a tns is * an unambiguous "ticket is busy" flag. */ #define TICKET_QUANTUM 2 /* * SMP ticket spinlocks, allowing only a single CPU anywhere * * (the type definitions are in asm/spinlock_types.h) */ static inline int arch_spin_is_locked(arch_spinlock_t *lock) { /* * Note that even if a new ticket is in the process of being * acquired, so lock->next_ticket is 1, it's still reasonable * to claim the lock is held, since it will be momentarily * if not already. There's no need to wait for a "valid" * lock->next_ticket to become available. * Use READ_ONCE() to ensure that calling this in a loop is OK. */ int curr = READ_ONCE(lock->current_ticket); int next = READ_ONCE(lock->next_ticket); return next != curr; } void arch_spin_lock(arch_spinlock_t *lock); int arch_spin_trylock(arch_spinlock_t *lock); static inline void arch_spin_unlock(arch_spinlock_t *lock) { /* For efficiency, overlap fetching the old ticket with the wmb(). */ int old_ticket = lock->current_ticket; wmb(); /* guarantee anything modified under the lock is visible */ lock->current_ticket = old_ticket + TICKET_QUANTUM; } /* * Read-write spinlocks, allowing multiple readers * but only one writer. * * We use a "tns/store-back" technique on a single word to manage * the lock state, looping around to retry if the tns returns 1. */ /* Internal layout of the word; do not use. */ #define _WR_NEXT_SHIFT 8 #define _WR_CURR_SHIFT 16 #define _WR_WIDTH 8 #define _RD_COUNT_SHIFT 24 #define _RD_COUNT_WIDTH 8 /** * arch_read_lock() - acquire a read lock. */ void arch_read_lock(arch_rwlock_t *rwlock); /** * arch_write_lock() - acquire a write lock. */ void arch_write_lock(arch_rwlock_t *rwlock); /** * arch_read_trylock() - try to acquire a read lock. */ int arch_read_trylock(arch_rwlock_t *rwlock); /** * arch_write_trylock() - try to acquire a write lock. */ int arch_write_trylock(arch_rwlock_t *rwlock); /** * arch_read_unlock() - release a read lock. */ void arch_read_unlock(arch_rwlock_t *rwlock); /** * arch_write_unlock() - release a write lock. */ void arch_write_unlock(arch_rwlock_t *rwlock); #endif /* _ASM_TILE_SPINLOCK_32_H */
Name | Type | Size | Permission | Actions |
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Kbuild | File | 439 B | 0644 |
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asm-offsets.h | File | 35 B | 0644 |
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atomic.h | File | 5.14 KB | 0644 |
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atomic_32.h | File | 8.91 KB | 0644 |
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atomic_64.h | File | 5.51 KB | 0644 |
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backtrace.h | File | 3.98 KB | 0644 |
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barrier.h | File | 2.89 KB | 0644 |
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bitops.h | File | 2.37 KB | 0644 |
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bitops_32.h | File | 4.01 KB | 0644 |
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bitops_64.h | File | 2.67 KB | 0644 |
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cache.h | File | 2.6 KB | 0644 |
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cacheflush.h | File | 4.94 KB | 0644 |
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checksum.h | File | 1.23 KB | 0644 |
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cmpxchg.h | File | 3.47 KB | 0644 |
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compat.h | File | 7.38 KB | 0644 |
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current.h | File | 947 B | 0644 |
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delay.h | File | 1.1 KB | 0644 |
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device.h | File | 978 B | 0644 |
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div64.h | File | 319 B | 0644 |
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dma-mapping.h | File | 1.82 KB | 0644 |
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dma.h | File | 762 B | 0644 |
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elf.h | File | 5.42 KB | 0644 |
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fixmap.h | File | 2.73 KB | 0644 |
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ftrace.h | File | 1.08 KB | 0644 |
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futex.h | File | 4.23 KB | 0644 |
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hardirq.h | File | 1.28 KB | 0644 |
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hardwall.h | File | 1.08 KB | 0644 |
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highmem.h | File | 2.08 KB | 0644 |
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homecache.h | File | 4.21 KB | 0644 |
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hugetlb.h | File | 3.04 KB | 0644 |
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hv_driver.h | File | 1.92 KB | 0644 |
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ide.h | File | 758 B | 0644 |
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insn.h | File | 1.79 KB | 0644 |
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io.h | File | 12.43 KB | 0644 |
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irq.h | File | 3.11 KB | 0644 |
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irq_work.h | File | 283 B | 0644 |
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irqflags.h | File | 10.55 KB | 0644 |
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jump_label.h | File | 1.47 KB | 0644 |
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kdebug.h | File | 769 B | 0644 |
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kexec.h | File | 2.23 KB | 0644 |
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kgdb.h | File | 1.99 KB | 0644 |
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kmap_types.h | File | 1.02 KB | 0644 |
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kprobes.h | File | 2.19 KB | 0644 |
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linkage.h | File | 1.46 KB | 0644 |
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mmu.h | File | 965 B | 0644 |
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mmu_context.h | File | 4.5 KB | 0644 |
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mmzone.h | File | 2.07 KB | 0644 |
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module.h | File | 1.12 KB | 0644 |
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page.h | File | 10.32 KB | 0644 |
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pci.h | File | 6.58 KB | 0644 |
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percpu.h | File | 1.79 KB | 0644 |
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perf_event.h | File | 766 B | 0644 |
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pgalloc.h | File | 4.76 KB | 0644 |
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pgtable.h | File | 15.66 KB | 0644 |
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pgtable_32.h | File | 4.08 KB | 0644 |
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pgtable_64.h | File | 5.11 KB | 0644 |
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pmc.h | File | 2.15 KB | 0644 |
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processor.h | File | 10.62 KB | 0644 |
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ptrace.h | File | 2.96 KB | 0644 |
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sections.h | File | 1.37 KB | 0644 |
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setup.h | File | 1.63 KB | 0644 |
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sigframe.h | File | 956 B | 0644 |
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signal.h | File | 1.07 KB | 0644 |
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smp.h | File | 3.98 KB | 0644 |
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spinlock.h | File | 741 B | 0644 |
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spinlock_32.h | File | 2.9 KB | 0644 |
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spinlock_64.h | File | 3.88 KB | 0644 |
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spinlock_types.h | File | 1.58 KB | 0644 |
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stack.h | File | 2.59 KB | 0644 |
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string.h | File | 1.19 KB | 0644 |
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switch_to.h | File | 2.75 KB | 0644 |
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syscall.h | File | 2.88 KB | 0644 |
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syscalls.h | File | 2.35 KB | 0644 |
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thread_info.h | File | 5.54 KB | 0644 |
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tile-desc.h | File | 650 B | 0644 |
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tile-desc_32.h | File | 12.54 KB | 0644 |
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tile-desc_64.h | File | 10.83 KB | 0644 |
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timex.h | File | 1.71 KB | 0644 |
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tlb.h | File | 878 B | 0644 |
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tlbflush.h | File | 3.99 KB | 0644 |
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topology.h | File | 1.52 KB | 0644 |
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traps.h | File | 2.44 KB | 0644 |
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uaccess.h | File | 12.77 KB | 0644 |
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unaligned.h | File | 1.56 KB | 0644 |
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unistd.h | File | 777 B | 0644 |
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user.h | File | 717 B | 0644 |
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vdso.h | File | 1.84 KB | 0644 |
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vga.h | File | 1.05 KB | 0644 |
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word-at-a-time.h | File | 1.07 KB | 0644 |
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