diff options
Diffstat (limited to 'arch/x86/xen/spinlock.c')
| -rw-r--r-- | arch/x86/xen/spinlock.c | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index cc9b1e182fc..d69cc6c3f80 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -116,9 +116,26 @@ static inline void spin_time_accum_blocked(u64 start) } #endif /* CONFIG_XEN_DEBUG_FS */ +/* + * Size struct xen_spinlock so it's the same as arch_spinlock_t. + */ +#if NR_CPUS < 256 +typedef u8 xen_spinners_t; +# define inc_spinners(xl) \ + asm(LOCK_PREFIX " incb %0" : "+m" ((xl)->spinners) : : "memory"); +# define dec_spinners(xl) \ + asm(LOCK_PREFIX " decb %0" : "+m" ((xl)->spinners) : : "memory"); +#else +typedef u16 xen_spinners_t; +# define inc_spinners(xl) \ + asm(LOCK_PREFIX " incw %0" : "+m" ((xl)->spinners) : : "memory"); +# define dec_spinners(xl) \ + asm(LOCK_PREFIX " decw %0" : "+m" ((xl)->spinners) : : "memory"); +#endif + struct xen_spinlock { unsigned char lock; /* 0 -> free; 1 -> locked */ - unsigned short spinners; /* count of waiting cpus */ + xen_spinners_t spinners; /* count of waiting cpus */ }; static int xen_spin_is_locked(struct arch_spinlock *lock) @@ -164,8 +181,7 @@ static inline struct xen_spinlock *spinning_lock(struct xen_spinlock *xl) wmb(); /* set lock of interest before count */ - asm(LOCK_PREFIX " incw %0" - : "+m" (xl->spinners) : : "memory"); + inc_spinners(xl); return prev; } @@ -176,8 +192,7 @@ static inline struct xen_spinlock *spinning_lock(struct xen_spinlock *xl) */ static inline void unspinning_lock(struct xen_spinlock *xl, struct xen_spinlock *prev) { - asm(LOCK_PREFIX " decw %0" - : "+m" (xl->spinners) : : "memory"); + dec_spinners(xl); wmb(); /* decrement count before restoring lock */ __this_cpu_write(lock_spinners, prev); } @@ -373,6 +388,8 @@ void xen_uninit_lock_cpu(int cpu) void __init xen_init_spinlocks(void) { + BUILD_BUG_ON(sizeof(struct xen_spinlock) > sizeof(arch_spinlock_t)); + pv_lock_ops.spin_is_locked = xen_spin_is_locked; pv_lock_ops.spin_is_contended = xen_spin_is_contended; pv_lock_ops.spin_lock = xen_spin_lock; |