cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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osq_lock.h (1066B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef __LINUX_OSQ_LOCK_H
      3#define __LINUX_OSQ_LOCK_H
      4
      5/*
      6 * An MCS like lock especially tailored for optimistic spinning for sleeping
      7 * lock implementations (mutex, rwsem, etc).
      8 */
      9struct optimistic_spin_node {
     10	struct optimistic_spin_node *next, *prev;
     11	int locked; /* 1 if lock acquired */
     12	int cpu; /* encoded CPU # + 1 value */
     13};
     14
     15struct optimistic_spin_queue {
     16	/*
     17	 * Stores an encoded value of the CPU # of the tail node in the queue.
     18	 * If the queue is empty, then it's set to OSQ_UNLOCKED_VAL.
     19	 */
     20	atomic_t tail;
     21};
     22
     23#define OSQ_UNLOCKED_VAL (0)
     24
     25/* Init macro and function. */
     26#define OSQ_LOCK_UNLOCKED { ATOMIC_INIT(OSQ_UNLOCKED_VAL) }
     27
     28static inline void osq_lock_init(struct optimistic_spin_queue *lock)
     29{
     30	atomic_set(&lock->tail, OSQ_UNLOCKED_VAL);
     31}
     32
     33extern bool osq_lock(struct optimistic_spin_queue *lock);
     34extern void osq_unlock(struct optimistic_spin_queue *lock);
     35
     36static inline bool osq_is_locked(struct optimistic_spin_queue *lock)
     37{
     38	return atomic_read(&lock->tail) != OSQ_UNLOCKED_VAL;
     39}
     40
     41#endif