linux_dsm_epyc7002/arch/x86/include/asm/qspinlock.h
Waiman Long 6c62985d57 x86/paravirt: Change vcp_is_preempted() arg type to long
The cpu argument in the function prototype of vcpu_is_preempted()
is changed from int to long. That makes it easier to provide a better
optimized assembly version of that function.

For Xen, vcpu_is_preempted(long) calls xen_vcpu_stolen(int), the
downcast from long to int is not a problem as vCPU number won't exceed
32 bits.

Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-02-21 12:48:06 +01:00

73 lines
1.8 KiB
C

#ifndef _ASM_X86_QSPINLOCK_H
#define _ASM_X86_QSPINLOCK_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
#define virt_spin_lock virt_spin_lock
static inline bool virt_spin_lock(struct qspinlock *lock)
{
if (!static_cpu_has(X86_FEATURE_HYPERVISOR))
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;
}
#endif /* CONFIG_PARAVIRT */
#include <asm-generic/qspinlock.h>
#endif /* _ASM_X86_QSPINLOCK_H */