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65 lines
2.7 KiB
C
65 lines
2.7 KiB
C
#ifndef COSMOPOLITAN_LIBC_INTRIN_SPINLOCK_H_
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#define COSMOPOLITAN_LIBC_INTRIN_SPINLOCK_H_
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#include "libc/bits/weaken.h"
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#include "libc/calls/calls.h"
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#include "libc/intrin/kprintf.h"
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#include "libc/log/backtrace.internal.h"
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#include "libc/log/log.h"
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#if defined(_SPINLOCK_DEBUG)
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#define _spinlock(lock) _spinlock_debug(lock)
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#elif defined(TINY)
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#define _spinlock(lock) _spinlock_tiny(lock)
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#else
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#define _spinlock(lock) _spinlock_optimistic(lock)
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#endif
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#define _spunlock(lock) __atomic_clear(lock, __ATOMIC_RELAXED)
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#define _trylock(lock) __atomic_test_and_set(lock, __ATOMIC_SEQ_CST)
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#define _seizelock(lock) \
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do { \
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typeof(*(lock)) x = 1; \
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__atomic_store(lock, &x, __ATOMIC_RELEASE); \
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} while (0)
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#define _spinlock_tiny(lock) \
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do { \
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while (_trylock(lock)) { \
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__builtin_ia32_pause(); \
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} \
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} while (0)
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#define _spinlock_optimistic(lock) \
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do { \
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for (;;) { \
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typeof(*(lock)) x; \
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__atomic_load(lock, &x, __ATOMIC_RELAXED); \
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if (!x && !_trylock(lock)) { \
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break; \
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} else { \
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__builtin_ia32_pause(); \
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} \
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} \
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} while (0)
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#define _spinlock_debug(lock) \
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do { \
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typeof(*(lock)) me, owner; \
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me = gettid(); \
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if (_trylock(lock)) { \
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__atomic_load(lock, &owner, __ATOMIC_RELAXED); \
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if (owner == me) { \
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kprintf("%s:%d: warning: possible spinlock re-entry in %s()\n", \
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__FILE__, __LINE__, __FUNCTION__); \
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if (weaken(ShowBacktrace)) { \
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weaken(ShowBacktrace)(2, 0); \
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} \
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} \
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_spinlock_optimistic(lock); \
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} \
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*lock = me; \
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} while (0)
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#endif /* COSMOPOLITAN_LIBC_INTRIN_SPINLOCK_H_ */
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