[mirror_ubuntu-bionic-kernel.git] / include / asm-generic / qspinlock_types.h

/*
 * Queued spinlock
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.  See the
 * GNU General Public License for more details.
 *
 * (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P.
 *
 * Authors: Waiman Long <waiman.long@hp.com>
 */
#ifndef __ASM_GENERIC_QSPINLOCK_TYPES_H
#define __ASM_GENERIC_QSPINLOCK_TYPES_H

/*
 * Including atomic.h with PARAVIRT on will cause compilation errors because
 * of recursive header file incluson via paravirt_types.h. So don't include
 * it if PARAVIRT is on.
 */
#ifndef CONFIG_PARAVIRT
#include <linux/types.h>
#include <linux/atomic.h>
#endif

typedef struct qspinlock {
	union {
		atomic_t val;

		/*
		 * By using the whole 2nd least significant byte for the
		 * pending bit, we can allow better optimization of the lock
		 * acquisition for the pending bit holder.
		 */
#ifdef __LITTLE_ENDIAN
		struct {
			u8	locked;
			u8	pending;
		};
		struct {
			u16	locked_pending;
			u16	tail;
		};
#else
		struct {
			u16	tail;
			u16	locked_pending;
		};
		struct {
			u8	reserved[2];
			u8	pending;
			u8	locked;
		};
#endif
	};
} arch_spinlock_t;

/*
 * Initializier
 */
#define	__ARCH_SPIN_LOCK_UNLOCKED	{ { .val = ATOMIC_INIT(0) } }

/*
 * Bitfields in the atomic value:
 *
 * When NR_CPUS < 16K
 *  0- 7: locked byte
 *     8: pending
 *  9-15: not used
 * 16-17: tail index
 * 18-31: tail cpu (+1)
 *
 * When NR_CPUS >= 16K
 *  0- 7: locked byte
 *     8: pending
 *  9-10: tail index
 * 11-31: tail cpu (+1)
 */
#define	_Q_SET_MASK(type)	(((1U << _Q_ ## type ## _BITS) - 1)\
				      << _Q_ ## type ## _OFFSET)
#define _Q_LOCKED_OFFSET	0
#define _Q_LOCKED_BITS		8
#define _Q_LOCKED_MASK		_Q_SET_MASK(LOCKED)

#define _Q_PENDING_OFFSET	(_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
#if CONFIG_NR_CPUS < (1U << 14)
#define _Q_PENDING_BITS		8
#else
#define _Q_PENDING_BITS		1
#endif
#define _Q_PENDING_MASK		_Q_SET_MASK(PENDING)

#define _Q_TAIL_IDX_OFFSET	(_Q_PENDING_OFFSET + _Q_PENDING_BITS)
#define _Q_TAIL_IDX_BITS	2
#define _Q_TAIL_IDX_MASK	_Q_SET_MASK(TAIL_IDX)

#define _Q_TAIL_CPU_OFFSET	(_Q_TAIL_IDX_OFFSET + _Q_TAIL_IDX_BITS)
#define _Q_TAIL_CPU_BITS	(32 - _Q_TAIL_CPU_OFFSET)
#define _Q_TAIL_CPU_MASK	_Q_SET_MASK(TAIL_CPU)

#define _Q_TAIL_OFFSET		_Q_TAIL_IDX_OFFSET
#define _Q_TAIL_MASK		(_Q_TAIL_IDX_MASK | _Q_TAIL_CPU_MASK)

#define _Q_LOCKED_VAL		(1U << _Q_LOCKED_OFFSET)
#define _Q_PENDING_VAL		(1U << _Q_PENDING_OFFSET)

#endif /* __ASM_GENERIC_QSPINLOCK_TYPES_H */
Commit	Line	Data
a33fda35 WL	1	/*
	2	* Queued spinlock
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation; either version 2 of the License, or
	7	* (at your option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P.
	15	*
	16	* Authors: Waiman Long <waiman.long@hp.com>
	17	*/
	18	#ifndef __ASM_GENERIC_QSPINLOCK_TYPES_H
	19	#define __ASM_GENERIC_QSPINLOCK_TYPES_H
	20
	21	/*
	22	* Including atomic.h with PARAVIRT on will cause compilation errors because
	23	* of recursive header file incluson via paravirt_types.h. So don't include
	24	* it if PARAVIRT is on.
	25	*/
	26	#ifndef CONFIG_PARAVIRT
	27	#include <linux/types.h>
	28	#include <linux/atomic.h>
	29	#endif
	30
	31	typedef struct qspinlock {
5c58f3ba WD	32	union {
	33	atomic_t val;
	34
	35	/*
	36	* By using the whole 2nd least significant byte for the
	37	* pending bit, we can allow better optimization of the lock
	38	* acquisition for the pending bit holder.
	39	*/
	40	#ifdef __LITTLE_ENDIAN
	41	struct {
	42	u8 locked;
	43	u8 pending;
	44	};
	45	struct {
	46	u16 locked_pending;
	47	u16 tail;
	48	};
	49	#else
	50	struct {
	51	u16 tail;
	52	u16 locked_pending;
	53	};
	54	struct {
	55	u8 reserved[2];
	56	u8 pending;
	57	u8 locked;
	58	};
	59	#endif
	60	};
a33fda35 WL	61	} arch_spinlock_t;
a33fda35 WL	62
b82e5302 DS	63	/*
	64	* Initializier
	65	*/
6a255ce3	66	#define __ARCH_SPIN_LOCK_UNLOCKED { { .val = ATOMIC_INIT(0) } }
b82e5302	67
a33fda35 WL	68	/*
	69	* Bitfields in the atomic value:
	70	*
69f9cae9 PZI	71	* When NR_CPUS < 16K
	72	* 0- 7: locked byte
	73	* 8: pending
	74	* 9-15: not used
	75	* 16-17: tail index
	76	* 18-31: tail cpu (+1)
	77	*
	78	* When NR_CPUS >= 16K
a33fda35	79	* 0- 7: locked byte
c1fb159d PZI	80	* 8: pending
	81	* 9-10: tail index
	82	* 11-31: tail cpu (+1)
a33fda35 WL	83	*/
	84	#define _Q_SET_MASK(type) (((1U << _Q_ ## type ## _BITS) - 1)\
	85	<< _Q_ ## type ## _OFFSET)
	86	#define _Q_LOCKED_OFFSET 0
	87	#define _Q_LOCKED_BITS 8
	88	#define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
	89
c1fb159d	90	#define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
69f9cae9 PZI	91	#if CONFIG_NR_CPUS < (1U << 14)
	92	#define _Q_PENDING_BITS 8
	93	#else
c1fb159d	94	#define _Q_PENDING_BITS 1
69f9cae9	95	#endif
c1fb159d PZI	96	#define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
	97
	98	#define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
a33fda35 WL	99	#define _Q_TAIL_IDX_BITS 2
	100	#define _Q_TAIL_IDX_MASK _Q_SET_MASK(TAIL_IDX)
	101
	102	#define _Q_TAIL_CPU_OFFSET (_Q_TAIL_IDX_OFFSET + _Q_TAIL_IDX_BITS)
	103	#define _Q_TAIL_CPU_BITS (32 - _Q_TAIL_CPU_OFFSET)
	104	#define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
	105
69f9cae9	106	#define _Q_TAIL_OFFSET _Q_TAIL_IDX_OFFSET
6403bd7d WL	107	#define _Q_TAIL_MASK (_Q_TAIL_IDX_MASK \| _Q_TAIL_CPU_MASK)
6403bd7d WL	108
a33fda35	109	#define _Q_LOCKED_VAL (1U << _Q_LOCKED_OFFSET)
c1fb159d	110	#define _Q_PENDING_VAL (1U << _Q_PENDING_OFFSET)
a33fda35 WL	111
a33fda35 WL	112	#endif /* __ASM_GENERIC_QSPINLOCK_TYPES_H */