116 lines
2.3 KiB
C
116 lines
2.3 KiB
C
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/* ------------------------------- **
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** Atomic locking for MIPS **
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** ------------------------------- */
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static __inline__ int test_and_set_bit(int nr, volatile void *addr)
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{
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int mask, retval, mw;
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mask = 1;
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do {
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mw = load_linked(addr);
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retval = (mask & mw) != 0;
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} while (!store_conditional(addr, mw|mask));
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return retval;
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}
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static inline void _spin_lock(__dummy_lock_t *lock)
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{
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unsigned int tmp;
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__asm__ __volatile__(
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".set\tnoreorder\t\t\t# spin_lock\n"
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"1:\tll\t%1, %2\n\t"
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"bnez\t%1, 1b\n\t"
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" li\t%1, 1\n\t"
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"sc\t%1, %0\n\t"
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"beqz\t%1, 1b\n\t"
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" sync\n\t"
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".set\treorder"
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: "=o" (__dummy_lock(lock)), "=&r" (tmp)
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: "o" (__dummy_lock(lock))
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: "memory");
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}
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static inline void spin_unlock(__dummy_lock_t *lock)
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{
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__asm__ __volatile__(
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".set\tnoreorder\t\t\t# spin_unlock\n\t"
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"sync\n\t"
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"sw\t$0, %0\n\t"
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".set\treorder"
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: "=o" (__dummy_lock(lock))
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: "o" (__dummy_lock(lock))
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: "memory");
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}
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static inline void _read_lock(rwlock_t *rw)
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{
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unsigned int tmp;
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__asm__ __volatile__(
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".set\tnoreorder\t\t\t# read_lock\n"
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"1:\tll\t%1, %2\n\t"
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"bltz\t%1, 1b\n\t"
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" addu\t%1, 1\n\t"
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"sc\t%1, %0\n\t"
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"beqz\t%1, 1b\n\t"
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" sync\n\t"
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".set\treorder"
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: "=o" (__dummy_lock(rw)), "=&r" (tmp)
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: "o" (__dummy_lock(rw))
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: "memory");
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}
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/* Note the use of sub, not subu which will make the kernel die with an
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overflow exception if we ever try to unlock an rwlock that is already
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unlocked or is being held by a writer. */
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static inline void _read_unlock(rwlock_t *rw)
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{
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unsigned int tmp;
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__asm__ __volatile__(
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".set\tnoreorder\t\t\t# read_unlock\n"
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"1:\tll\t%1, %2\n\t"
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"sub\t%1, 1\n\t"
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"sc\t%1, %0\n\t"
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"beqz\t%1, 1b\n\t"
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".set\treorder"
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: "=o" (__dummy_lock(rw)), "=&r" (tmp)
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: "o" (__dummy_lock(rw))
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: "memory");
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}
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static inline void _write_lock(rwlock_t *rw)
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{
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unsigned int tmp;
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__asm__ __volatile__(
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".set\tnoreorder\t\t\t# write_lock\n"
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"1:\tll\t%1, %2\n\t"
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"bnez\t%1, 1b\n\t"
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" lui\t%1, 0x8000\n\t"
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"sc\t%1, %0\n\t"
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"beqz\t%1, 1b\n\t"
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" sync\n\t"
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".set\treorder"
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: "=o" (__dummy_lock(rw)), "=&r" (tmp)
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: "o" (__dummy_lock(rw))
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: "memory");
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}
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static inline void _write_unlock(rwlock_t *rw)
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{
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__asm__ __volatile__(
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".set\tnoreorder\t\t\t# write_unlock\n\t"
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"sync\n\t"
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"sw\t$0, %0\n\t"
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".set\treorder"
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: "=o" (__dummy_lock(rw))
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: "o" (__dummy_lock(rw))
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: "memory");
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}
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