| /* SPDX-License-Identifier: GPL-2.0 */ | |
| #ifndef _ASM_LOONGARCH_QSPINLOCK_H | |
| #define _ASM_LOONGARCH_QSPINLOCK_H | |
| #include <linux/jump_label.h> | |
| #ifdef CONFIG_PARAVIRT | |
| DECLARE_STATIC_KEY_FALSE(virt_spin_lock_key); | |
| #define virt_spin_lock virt_spin_lock | |
| static inline bool virt_spin_lock(struct qspinlock *lock) | |
| { | |
| int val; | |
| if (!static_branch_unlikely(&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. | |
| */ | |
| __retry: | |
| val = atomic_read(&lock->val); | |
| if (val || !atomic_try_cmpxchg(&lock->val, &val, _Q_LOCKED_VAL)) { | |
| cpu_relax(); | |
| goto __retry; | |
| } | |
| return true; | |
| } | |
| #endif /* CONFIG_PARAVIRT */ | |
| #include <asm-generic/qspinlock.h> | |
| #endif // _ASM_LOONGARCH_QSPINLOCK_H |