[mirror_ubuntu-artful-kernel.git] / arch / powerpc / include / asm / mutex.h

/*
 * Optimised mutex implementation of include/asm-generic/mutex-dec.h algorithm
 */
#ifndef _ASM_POWERPC_MUTEX_H
#define _ASM_POWERPC_MUTEX_H

static inline int __mutex_cmpxchg_lock(atomic_t *v, int old, int new)
{
	int t;

	__asm__ __volatile__ (
"1:	lwarx	%0,0,%1		# mutex trylock\n\
	cmpw	0,%0,%2\n\
	bne-	2f\n"
	PPC405_ERR77(0,%1)
"	stwcx.	%3,0,%1\n\
	bne-	1b"
	PPC_ACQUIRE_BARRIER
	"\n\
2:"
	: "=&r" (t)
	: "r" (&v->counter), "r" (old), "r" (new)
	: "cc", "memory");

	return t;
}

static inline int __mutex_dec_return_lock(atomic_t *v)
{
	int t;

	__asm__ __volatile__(
"1:	lwarx	%0,0,%1		# mutex lock\n\
	addic	%0,%0,-1\n"
	PPC405_ERR77(0,%1)
"	stwcx.	%0,0,%1\n\
	bne-	1b"
	PPC_ACQUIRE_BARRIER
	: "=&r" (t)
	: "r" (&v->counter)
	: "cc", "memory");

	return t;
}

static inline int __mutex_inc_return_unlock(atomic_t *v)
{
	int t;

	__asm__ __volatile__(
	PPC_RELEASE_BARRIER
"1:	lwarx	%0,0,%1		# mutex unlock\n\
	addic	%0,%0,1\n"
	PPC405_ERR77(0,%1)
"	stwcx.	%0,0,%1 \n\
	bne-	1b"
	: "=&r" (t)
	: "r" (&v->counter)
	: "cc", "memory");

	return t;
}

/**
 *  __mutex_fastpath_lock - try to take the lock by moving the count
 *                          from 1 to a 0 value
 *  @count: pointer of type atomic_t
 *  @fail_fn: function to call if the original value was not 1
 *
 * Change the count from 1 to a value lower than 1, and call <fail_fn> if
 * it wasn't 1 originally. This function MUST leave the value lower than
 * 1 even when the "1" assertion wasn't true.
 */
static inline void
__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
	if (unlikely(__mutex_dec_return_lock(count) < 0))
		fail_fn(count);
}

/**
 *  __mutex_fastpath_lock_retval - try to take the lock by moving the count
 *                                 from 1 to a 0 value
 *  @count: pointer of type atomic_t
 *  @fail_fn: function to call if the original value was not 1
 *
 * Change the count from 1 to a value lower than 1, and call <fail_fn> if
 * it wasn't 1 originally. This function returns 0 if the fastpath succeeds,
 * or anything the slow path function returns.
 */
static inline int
__mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
{
	if (unlikely(__mutex_dec_return_lock(count) < 0))
		return fail_fn(count);
	return 0;
}

/**
 *  __mutex_fastpath_unlock - try to promote the count from 0 to 1
 *  @count: pointer of type atomic_t
 *  @fail_fn: function to call if the original value was not 0
 *
 * Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>.
 * In the failure case, this function is allowed to either set the value to
 * 1, or to set it to a value lower than 1.
 */
static inline void
__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
{
	if (unlikely(__mutex_inc_return_unlock(count) <= 0))
		fail_fn(count);
}

#define __mutex_slowpath_needs_to_unlock()		1

/**
 * __mutex_fastpath_trylock - try to acquire the mutex, without waiting
 *
 *  @count: pointer of type atomic_t
 *  @fail_fn: fallback function
 *
 * Change the count from 1 to 0, and return 1 (success), or if the count
 * was not 1, then return 0 (failure).
 */
static inline int
__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
{
	if (likely(__mutex_cmpxchg_lock(count, 1, 0) == 1))
		return 1;
	return 0;
}

#endif
Commit	Line	Data
2acbb8c6	1	/*
ae564c63 NP	2	* Optimised mutex implementation of include/asm-generic/mutex-dec.h algorithm
	3	*/
	4	#ifndef _ASM_POWERPC_MUTEX_H
	5	#define _ASM_POWERPC_MUTEX_H
	6
	7	static inline int __mutex_cmpxchg_lock(atomic_t *v, int old, int new)
	8	{
	9	int t;
	10
	11	__asm__ __volatile__ (
	12	"1: lwarx %0,0,%1 # mutex trylock\n\
	13	cmpw 0,%0,%2\n\
	14	bne- 2f\n"
	15	PPC405_ERR77(0,%1)
	16	" stwcx. %3,0,%1\n\
	17	bne- 1b"
f10e2e5b	18	PPC_ACQUIRE_BARRIER
ae564c63 NP	19	"\n\
	20	2:"
	21	: "=&r" (t)
	22	: "r" (&v->counter), "r" (old), "r" (new)
	23	: "cc", "memory");
	24
	25	return t;
	26	}
	27
	28	static inline int __mutex_dec_return_lock(atomic_t *v)
	29	{
	30	int t;
	31
	32	__asm__ __volatile__(
	33	"1: lwarx %0,0,%1 # mutex lock\n\
	34	addic %0,%0,-1\n"
	35	PPC405_ERR77(0,%1)
	36	" stwcx. %0,0,%1\n\
	37	bne- 1b"
f10e2e5b	38	PPC_ACQUIRE_BARRIER
ae564c63 NP	39	: "=&r" (t)
	40	: "r" (&v->counter)
	41	: "cc", "memory");
	42
	43	return t;
	44	}
	45
	46	static inline int __mutex_inc_return_unlock(atomic_t *v)
	47	{
	48	int t;
	49
	50	__asm__ __volatile__(
f10e2e5b	51	PPC_RELEASE_BARRIER
ae564c63 NP	52	"1: lwarx %0,0,%1 # mutex unlock\n\
	53	addic %0,%0,1\n"
	54	PPC405_ERR77(0,%1)
	55	" stwcx. %0,0,%1 \n\
	56	bne- 1b"
	57	: "=&r" (t)
	58	: "r" (&v->counter)
	59	: "cc", "memory");
	60
	61	return t;
	62	}
	63
	64	/**
	65	* __mutex_fastpath_lock - try to take the lock by moving the count
	66	* from 1 to a 0 value
	67	* @count: pointer of type atomic_t
	68	* @fail_fn: function to call if the original value was not 1
	69	*
	70	* Change the count from 1 to a value lower than 1, and call <fail_fn> if
	71	* it wasn't 1 originally. This function MUST leave the value lower than
	72	* 1 even when the "1" assertion wasn't true.
	73	*/
	74	static inline void
	75	__mutex_fastpath_lock(atomic_t count, void (fail_fn)(atomic_t *))
	76	{
	77	if (unlikely(__mutex_dec_return_lock(count) < 0))
	78	fail_fn(count);
	79	}
	80
	81	/**
	82	* __mutex_fastpath_lock_retval - try to take the lock by moving the count
	83	* from 1 to a 0 value
	84	* @count: pointer of type atomic_t
	85	* @fail_fn: function to call if the original value was not 1
	86	*
	87	* Change the count from 1 to a value lower than 1, and call <fail_fn> if
	88	* it wasn't 1 originally. This function returns 0 if the fastpath succeeds,
	89	* or anything the slow path function returns.
	90	*/
	91	static inline int
	92	__mutex_fastpath_lock_retval(atomic_t count, int (fail_fn)(atomic_t *))
	93	{
	94	if (unlikely(__mutex_dec_return_lock(count) < 0))
	95	return fail_fn(count);
	96	return 0;
	97	}
	98
	99	/**
	100	* __mutex_fastpath_unlock - try to promote the count from 0 to 1
	101	* @count: pointer of type atomic_t
	102	* @fail_fn: function to call if the original value was not 0
	103	*
	104	* Try to promote the count from 0 to 1. If it wasn't 0, call <fail_fn>.
	105	* In the failure case, this function is allowed to either set the value to
	106	* 1, or to set it to a value lower than 1.
	107	*/
	108	static inline void
	109	__mutex_fastpath_unlock(atomic_t count, void (fail_fn)(atomic_t *))
	110	{
	111	if (unlikely(__mutex_inc_return_unlock(count) <= 0))
	112	fail_fn(count);
	113	}
	114
	115	#define __mutex_slowpath_needs_to_unlock() 1
116
117	/**
118	* __mutex_fastpath_trylock - try to acquire the mutex, without waiting
119	*
120	* @count: pointer of type atomic_t
121	* @fail_fn: fallback function
2acbb8c6	122	*
ae564c63 NP	123	* Change the count from 1 to 0, and return 1 (success), or if the count
ae564c63 NP	124	* was not 1, then return 0 (failure).
2acbb8c6	125	*/
ae564c63 NP	126	static inline int
	127	__mutex_fastpath_trylock(atomic_t count, int (fail_fn)(atomic_t *))
	128	{
	129	if (likely(__mutex_cmpxchg_lock(count, 1, 0) == 1))
	130	return 1;
	131	return 0;
	132	}
2acbb8c6	133
ae564c63	134	#endif