/* * 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 [31mCONFIG_PARAVIRT[0m #include <linux/types.h> #include <linux/atomic.h> #endif typedef struct qspinlock { atomic_t val; } arch_spinlock_t; /* * Initializier */ #define __ARCH_SPIN_LOCK_UNLOCKED { 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 [31mCONFIG_NR_CPUS[0m < (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 */ |