/* * include/asm-xtensa/spinlock.h * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 2001 - 2005 Tensilica Inc. */ #ifndef _XTENSA_SPINLOCK_H #define _XTENSA_SPINLOCK_H #include <asm/barrier.h> #include <asm/processor.h> /* * spinlock * * There is at most one owner of a spinlock. There are not different * types of spinlock owners like there are for rwlocks (see below). * * When trying to obtain a spinlock, the function "spins" forever, or busy- * waits, until the lock is obtained. When spinning, presumably some other * owner will soon give up the spinlock making it available to others. Use * the trylock functions to avoid spinning forever. * * possible values: * * 0 nobody owns the spinlock * 1 somebody owns the spinlock */ #define arch_spin_is_locked(x) ((x)->slock != 0) static inline void arch_spin_lock(arch_spinlock_t *lock) { unsigned long tmp; __asm__ __volatile__( " movi %0, 0\n" " wsr %0, scompare1\n" "1: movi %0, 1\n" " s32c1i %0, %1, 0\n" " bnez %0, 1b\n" : "=&a" (tmp) : "a" (&lock->slock) : "memory"); } /* Returns 1 if the lock is obtained, 0 otherwise. */ static inline int arch_spin_trylock(arch_spinlock_t *lock) { unsigned long tmp; __asm__ __volatile__( " movi %0, 0\n" " wsr %0, scompare1\n" " movi %0, 1\n" " s32c1i %0, %1, 0\n" : "=&a" (tmp) : "a" (&lock->slock) : "memory"); return tmp == 0 ? 1 : 0; } static inline void arch_spin_unlock(arch_spinlock_t *lock) { unsigned long tmp; __asm__ __volatile__( " movi %0, 0\n" " s32ri %0, %1, 0\n" : "=&a" (tmp) : "a" (&lock->slock) : "memory"); } /* * rwlock * * Read-write locks are really a more flexible spinlock. They allow * multiple readers but only one writer. Write ownership is exclusive * (i.e., all other readers and writers are blocked from ownership while * there is a write owner). These rwlocks are unfair to writers. Writers * can be starved for an indefinite time by readers. * * possible values: * * 0 nobody owns the rwlock * >0 one or more readers own the rwlock * (the positive value is the actual number of readers) * 0x80000000 one writer owns the rwlock, no other writers, no readers */ static inline void arch_write_lock(arch_rwlock_t *rw) { unsigned long tmp; __asm__ __volatile__( " movi %0, 0\n" " wsr %0, scompare1\n" "1: movi %0, 1\n" " slli %0, %0, 31\n" " s32c1i %0, %1, 0\n" " bnez %0, 1b\n" : "=&a" (tmp) : "a" (&rw->lock) : "memory"); } /* Returns 1 if the lock is obtained, 0 otherwise. */ static inline int arch_write_trylock(arch_rwlock_t *rw) { unsigned long tmp; __asm__ __volatile__( " movi %0, 0\n" " wsr %0, scompare1\n" " movi %0, 1\n" " slli %0, %0, 31\n" " s32c1i %0, %1, 0\n" : "=&a" (tmp) : "a" (&rw->lock) : "memory"); return tmp == 0 ? 1 : 0; } static inline void arch_write_unlock(arch_rwlock_t *rw) { unsigned long tmp; __asm__ __volatile__( " movi %0, 0\n" " s32ri %0, %1, 0\n" : "=&a" (tmp) : "a" (&rw->lock) : "memory"); } static inline void arch_read_lock(arch_rwlock_t *rw) { unsigned long tmp; unsigned long result; __asm__ __volatile__( "1: l32i %1, %2, 0\n" " bltz %1, 1b\n" " wsr %1, scompare1\n" " addi %0, %1, 1\n" " s32c1i %0, %2, 0\n" " bne %0, %1, 1b\n" : "=&a" (result), "=&a" (tmp) : "a" (&rw->lock) : "memory"); } /* Returns 1 if the lock is obtained, 0 otherwise. */ static inline int arch_read_trylock(arch_rwlock_t *rw) { unsigned long result; unsigned long tmp; __asm__ __volatile__( " l32i %1, %2, 0\n" " addi %0, %1, 1\n" " bltz %0, 1f\n" " wsr %1, scompare1\n" " s32c1i %0, %2, 0\n" " sub %0, %0, %1\n" "1:\n" : "=&a" (result), "=&a" (tmp) : "a" (&rw->lock) : "memory"); return result == 0; } static inline void arch_read_unlock(arch_rwlock_t *rw) { unsigned long tmp1, tmp2; __asm__ __volatile__( "1: l32i %1, %2, 0\n" " addi %0, %1, -1\n" " wsr %1, scompare1\n" " s32c1i %0, %2, 0\n" " bne %0, %1, 1b\n" : "=&a" (tmp1), "=&a" (tmp2) : "a" (&rw->lock) : "memory"); } #endif /* _XTENSA_SPINLOCK_H */
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asm-offsets.h | File | 35 B | 0644 |
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asm-uaccess.h | File | 4.11 KB | 0644 |
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asmmacro.h | File | 2.76 KB | 0644 |
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atomic.h | File | 7.38 KB | 0644 |
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barrier.h | File | 542 B | 0644 |
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bitops.h | File | 5.08 KB | 0644 |
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bootparam.h | File | 1.37 KB | 0644 |
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bugs.h | File | 451 B | 0644 |
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cache.h | File | 969 B | 0644 |
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cacheasm.h | File | 3.77 KB | 0644 |
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cacheflush.h | File | 5.76 KB | 0644 |
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checksum.h | File | 6 KB | 0644 |
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cmpxchg.h | File | 3.9 KB | 0644 |
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coprocessor.h | File | 5.05 KB | 0644 |
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current.h | File | 675 B | 0644 |
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delay.h | File | 1.63 KB | 0644 |
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dma-mapping.h | File | 855 B | 0644 |
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dma.h | File | 1.79 KB | 0644 |
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elf.h | File | 5.75 KB | 0644 |
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fixmap.h | File | 2.5 KB | 0644 |
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flat.h | File | 686 B | 0644 |
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ftrace.h | File | 979 B | 0644 |
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futex.h | File | 2.59 KB | 0644 |
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highmem.h | File | 2.33 KB | 0644 |
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hw_breakpoint.h | File | 1.45 KB | 0644 |
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hw_irq.h | File | 320 B | 0644 |
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initialize_mmu.h | File | 4.58 KB | 0644 |
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io.h | File | 2.09 KB | 0644 |
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irq.h | File | 1.46 KB | 0644 |
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irqflags.h | File | 1.99 KB | 0644 |
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kmem_layout.h | File | 2.07 KB | 0644 |
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mmu.h | File | 462 B | 0644 |
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mmu_context.h | File | 3.62 KB | 0644 |
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module.h | File | 525 B | 0644 |
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mxregs.h | File | 1.3 KB | 0644 |
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nommu_context.h | File | 602 B | 0644 |
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page.h | File | 5.69 KB | 0644 |
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pci-bridge.h | File | 2.16 KB | 0644 |
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pci.h | File | 1.37 KB | 0644 |
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perf_event.h | File | 108 B | 0644 |
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pgalloc.h | File | 1.84 KB | 0644 |
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pgtable.h | File | 14.89 KB | 0644 |
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platform.h | File | 1.75 KB | 0644 |
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processor.h | File | 7.44 KB | 0644 |
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ptrace.h | File | 3.74 KB | 0644 |
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regs.h | File | 3.87 KB | 0644 |
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segment.h | File | 376 B | 0644 |
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serial.h | File | 443 B | 0644 |
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shmparam.h | File | 561 B | 0644 |
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signal.h | File | 502 B | 0644 |
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smp.h | File | 967 B | 0644 |
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spinlock.h | File | 4.6 KB | 0644 |
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spinlock_types.h | File | 412 B | 0644 |
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stacktrace.h | File | 1.13 KB | 0644 |
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string.h | File | 2.65 KB | 0644 |
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switch_to.h | File | 601 B | 0644 |
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syscall.h | File | 982 B | 0644 |
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sysmem.h | File | 426 B | 0644 |
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thread_info.h | File | 3.62 KB | 0644 |
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timex.h | File | 1.79 KB | 0644 |
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tlb.h | File | 1.1 KB | 0644 |
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tlbflush.h | File | 5.53 KB | 0644 |
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traps.h | File | 1.87 KB | 0644 |
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types.h | File | 501 B | 0644 |
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uaccess.h | File | 8.67 KB | 0644 |
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ucontext.h | File | 540 B | 0644 |
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unaligned.h | File | 864 B | 0644 |
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unistd.h | File | 639 B | 0644 |
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user.h | File | 507 B | 0644 |
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vectors.h | File | 4.05 KB | 0644 |
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vga.h | File | 434 B | 0644 |
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