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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_QSPINLOCK_H
#define _ASM_X86_QSPINLOCK_H
#include <linux/jump_label.h>
#include <asm/cpufeature.h>
#include <asm-generic/qspinlock_types.h>
#include <asm/paravirt.h>
#define queued_spin_unlock queued_spin_unlock
/**
* queued_spin_unlock - release a queued spinlock
* @lock : Pointer to queued spinlock structure
*
* A smp_store_release() on the least-significant byte.
*/
static inline void native_queued_spin_unlock(struct qspinlock *lock)
{
smp_store_release((u8 *)lock, 0);
}
#ifdef CONFIG_PARAVIRT_SPINLOCKS
extern void native_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
extern void __pv_init_lock_hash(void);
extern void __pv_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
extern void __raw_callee_save___pv_queued_spin_unlock(struct qspinlock *lock);
static inline void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
{
pv_queued_spin_lock_slowpath(lock, val);
}
static inline void queued_spin_unlock(struct qspinlock *lock)
{
pv_queued_spin_unlock(lock);
}
#define vcpu_is_preempted vcpu_is_preempted
static inline bool vcpu_is_preempted(long cpu)
{
return pv_vcpu_is_preempted(cpu);
}
#else
static inline void queued_spin_unlock(struct qspinlock *lock)
{
native_queued_spin_unlock(lock);
}
#endif
#ifdef CONFIG_PARAVIRT
DECLARE_STATIC_KEY_TRUE(virt_spin_lock_key);
void native_pv_lock_init(void) __init;
#define virt_spin_lock virt_spin_lock
static inline bool virt_spin_lock(struct qspinlock *lock)
{
if (!static_branch_likely(&virt_spin_lock_key))
return false;
/*
* On hypervisors without PARAVIRT_SPINLOCKS support we fall
* back to a Test-and-Set spinlock, because fair locks have
* horrible lock 'holder' preemption issues.
*/
do {
while (atomic_read(&lock->val) != 0)
cpu_relax();
} while (atomic_cmpxchg(&lock->val, 0, _Q_LOCKED_VAL) != 0);
return true;
}
#else
static inline void native_pv_lock_init(void)
{
}
#endif /* CONFIG_PARAVIRT */
#include <asm-generic/qspinlock.h>
#endif /* _ASM_X86_QSPINLOCK_H */
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