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/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2010-2014 Intel Corporation
*/
#ifndef _RTE_SPINLOCK_H_
#define _RTE_SPINLOCK_H_
/**
* @file
*
* RTE Spinlocks
*
* This file defines an API for read-write locks, which are implemented
* in an architecture-specific way. This kind of lock simply waits in
* a loop repeatedly checking until the lock becomes available.
*
* All locks must be initialised before use, and only initialised once.
*
*/
#include <rte_lcore.h>
#ifdef RTE_FORCE_INTRINSICS
#include <rte_common.h>
#endif
#include <rte_pause.h>
/**
* The rte_spinlock_t type.
*/
typedef struct {
volatile int locked; /**< lock status 0 = unlocked, 1 = locked */
} rte_spinlock_t;
/**
* A static spinlock initializer.
*/
#define RTE_SPINLOCK_INITIALIZER { 0 }
/**
* Initialize the spinlock to an unlocked state.
*
* @param sl
* A pointer to the spinlock.
*/
static inline void
rte_spinlock_init(rte_spinlock_t *sl)
{
sl->locked = 0;
}
/**
* Take the spinlock.
*
* @param sl
* A pointer to the spinlock.
*/
static inline void
rte_spinlock_lock(rte_spinlock_t *sl);
#ifdef RTE_FORCE_INTRINSICS
static inline void
rte_spinlock_lock(rte_spinlock_t *sl)
{
while (__sync_lock_test_and_set(&sl->locked, 1))
while(sl->locked)
rte_pause();
}
#endif
/**
* Release the spinlock.
*
* @param sl
* A pointer to the spinlock.
*/
static inline void
rte_spinlock_unlock (rte_spinlock_t *sl);
#ifdef RTE_FORCE_INTRINSICS
static inline void
rte_spinlock_unlock (rte_spinlock_t *sl)
{
__sync_lock_release(&sl->locked);
}
#endif
/**
* Try to take the lock.
*
* @param sl
* A pointer to the spinlock.
* @return
* 1 if the lock is successfully taken; 0 otherwise.
*/
static inline int
rte_spinlock_trylock (rte_spinlock_t *sl);
#ifdef RTE_FORCE_INTRINSICS
static inline int
rte_spinlock_trylock (rte_spinlock_t *sl)
{
return __sync_lock_test_and_set(&sl->locked,1) == 0;
}
#endif
/**
* Test if the lock is taken.
*
* @param sl
* A pointer to the spinlock.
* @return
* 1 if the lock is currently taken; 0 otherwise.
*/
static inline int rte_spinlock_is_locked (rte_spinlock_t *sl)
{
return sl->locked;
}
/**
* Test if hardware transactional memory (lock elision) is supported
*
* @return
* 1 if the hardware transactional memory is supported; 0 otherwise.
*/
static inline int rte_tm_supported(void);
/**
* Try to execute critical section in a hardware memory transaction,
* if it fails or not available take the spinlock.
*
* NOTE: An attempt to perform a HW I/O operation inside a hardware memory
* transaction always aborts the transaction since the CPU is not able to
* roll-back should the transaction fail. Therefore, hardware transactional
* locks are not advised to be used around rte_eth_rx_burst() and
* rte_eth_tx_burst() calls.
*
* @param sl
* A pointer to the spinlock.
*/
static inline void
rte_spinlock_lock_tm(rte_spinlock_t *sl);
/**
* Commit hardware memory transaction or release the spinlock if
* the spinlock is used as a fall-back
*
* @param sl
* A pointer to the spinlock.
*/
static inline void
rte_spinlock_unlock_tm(rte_spinlock_t *sl);
/**
* Try to execute critical section in a hardware memory transaction,
* if it fails or not available try to take the lock.
*
* NOTE: An attempt to perform a HW I/O operation inside a hardware memory
* transaction always aborts the transaction since the CPU is not able to
* roll-back should the transaction fail. Therefore, hardware transactional
* locks are not advised to be used around rte_eth_rx_burst() and
* rte_eth_tx_burst() calls.
*
* @param sl
* A pointer to the spinlock.
* @return
* 1 if the hardware memory transaction is successfully started
* or lock is successfully taken; 0 otherwise.
*/
static inline int
rte_spinlock_trylock_tm(rte_spinlock_t *sl);
/**
* The rte_spinlock_recursive_t type.
*/
typedef struct {
rte_spinlock_t sl; /**< the actual spinlock */
volatile int user; /**< core id using lock, -1 for unused */
volatile int count; /**< count of time this lock has been called */
} rte_spinlock_recursive_t;
/**
* A static recursive spinlock initializer.
*/
#define RTE_SPINLOCK_RECURSIVE_INITIALIZER {RTE_SPINLOCK_INITIALIZER, -1, 0}
/**
* Initialize the recursive spinlock to an unlocked state.
*
* @param slr
* A pointer to the recursive spinlock.
*/
static inline void rte_spinlock_recursive_init(rte_spinlock_recursive_t *slr)
{
rte_spinlock_init(&slr->sl);
slr->user = -1;
slr->count = 0;
}
/**
* Take the recursive spinlock.
*
* @param slr
* A pointer to the recursive spinlock.
*/
static inline void rte_spinlock_recursive_lock(rte_spinlock_recursive_t *slr)
{
int id = rte_gettid();
if (slr->user != id) {
rte_spinlock_lock(&slr->sl);
slr->user = id;
}
slr->count++;
}
/**
* Release the recursive spinlock.
*
* @param slr
* A pointer to the recursive spinlock.
*/
static inline void rte_spinlock_recursive_unlock(rte_spinlock_recursive_t *slr)
{
if (--(slr->count) == 0) {
slr->user = -1;
rte_spinlock_unlock(&slr->sl);
}
}
/**
* Try to take the recursive lock.
*
* @param slr
* A pointer to the recursive spinlock.
* @return
* 1 if the lock is successfully taken; 0 otherwise.
*/
static inline int rte_spinlock_recursive_trylock(rte_spinlock_recursive_t *slr)
{
int id = rte_gettid();
if (slr->user != id) {
if (rte_spinlock_trylock(&slr->sl) == 0)
return 0;
slr->user = id;
}
slr->count++;
return 1;
}
/**
* Try to execute critical section in a hardware memory transaction,
* if it fails or not available take the recursive spinlocks
*
* NOTE: An attempt to perform a HW I/O operation inside a hardware memory
* transaction always aborts the transaction since the CPU is not able to
* roll-back should the transaction fail. Therefore, hardware transactional
* locks are not advised to be used around rte_eth_rx_burst() and
* rte_eth_tx_burst() calls.
*
* @param slr
* A pointer to the recursive spinlock.
*/
static inline void rte_spinlock_recursive_lock_tm(
rte_spinlock_recursive_t *slr);
/**
* Commit hardware memory transaction or release the recursive spinlock
* if the recursive spinlock is used as a fall-back
*
* @param slr
* A pointer to the recursive spinlock.
*/
static inline void rte_spinlock_recursive_unlock_tm(
rte_spinlock_recursive_t *slr);
/**
* Try to execute critical section in a hardware memory transaction,
* if it fails or not available try to take the recursive lock
*
* NOTE: An attempt to perform a HW I/O operation inside a hardware memory
* transaction always aborts the transaction since the CPU is not able to
* roll-back should the transaction fail. Therefore, hardware transactional
* locks are not advised to be used around rte_eth_rx_burst() and
* rte_eth_tx_burst() calls.
*
* @param slr
* A pointer to the recursive spinlock.
* @return
* 1 if the hardware memory transaction is successfully started
* or lock is successfully taken; 0 otherwise.
*/
static inline int rte_spinlock_recursive_trylock_tm(
rte_spinlock_recursive_t *slr);
#endif /* _RTE_SPINLOCK_H_ */
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