X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=include%2Fasm-x86%2Fspinlock.h;h=4f9a9861799ac648d406856a8a5ed1881e678a25;hb=77508ec8e6ed72c9ba8ca74248a7aabd664e3f57;hp=bc6376f1bc5a9d8029c8448b49fcba8685c9b7b8;hpb=cf867ac375cea7c7a834eaddaf373e2662d9e260;p=linux-2.6-omap-h63xx.git diff --git a/include/asm-x86/spinlock.h b/include/asm-x86/spinlock.h index bc6376f1bc5..4f9a9861799 100644 --- a/include/asm-x86/spinlock.h +++ b/include/asm-x86/spinlock.h @@ -6,7 +6,7 @@ #include #include #include - +#include /* * Your basic SMP spinlocks, allowing only a single CPU anywhere * @@ -20,18 +20,8 @@ */ #ifdef CONFIG_X86_32 -typedef char _slock_t; -# define LOCK_INS_DEC "decb" -# define LOCK_INS_XCH "xchgb" -# define LOCK_INS_MOV "movb" -# define LOCK_INS_CMP "cmpb" # define LOCK_PTR_REG "a" #else -typedef int _slock_t; -# define LOCK_INS_DEC "decl" -# define LOCK_INS_XCH "xchgl" -# define LOCK_INS_MOV "movl" -# define LOCK_INS_CMP "cmpl" # define LOCK_PTR_REG "D" #endif @@ -64,21 +54,21 @@ typedef int _slock_t; * much between them in performance though, especially as locks are out of line. */ #if (NR_CPUS < 256) -static inline int __raw_spin_is_locked(raw_spinlock_t *lock) +static inline int __ticket_spin_is_locked(raw_spinlock_t *lock) { - int tmp = *(volatile signed int *)(&(lock)->slock); + int tmp = ACCESS_ONCE(lock->slock); return (((tmp >> 8) & 0xff) != (tmp & 0xff)); } -static inline int __raw_spin_is_contended(raw_spinlock_t *lock) +static inline int __ticket_spin_is_contended(raw_spinlock_t *lock) { - int tmp = *(volatile signed int *)(&(lock)->slock); + int tmp = ACCESS_ONCE(lock->slock); return (((tmp >> 8) & 0xff) - (tmp & 0xff)) > 1; } -static __always_inline void __raw_spin_lock(raw_spinlock_t *lock) +static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock) { short inc = 0x0100; @@ -97,9 +87,7 @@ static __always_inline void __raw_spin_lock(raw_spinlock_t *lock) : "memory", "cc"); } -#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock) - -static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock) +static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock) { int tmp; short new; @@ -120,7 +108,7 @@ static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock) return tmp; } -static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock) +static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock) { asm volatile(UNLOCK_LOCK_PREFIX "incb %0" : "+m" (lock->slock) @@ -128,21 +116,21 @@ static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock) : "memory", "cc"); } #else -static inline int __raw_spin_is_locked(raw_spinlock_t *lock) +static inline int __ticket_spin_is_locked(raw_spinlock_t *lock) { - int tmp = *(volatile signed int *)(&(lock)->slock); + int tmp = ACCESS_ONCE(lock->slock); return (((tmp >> 16) & 0xffff) != (tmp & 0xffff)); } -static inline int __raw_spin_is_contended(raw_spinlock_t *lock) +static inline int __ticket_spin_is_contended(raw_spinlock_t *lock) { - int tmp = *(volatile signed int *)(&(lock)->slock); + int tmp = ACCESS_ONCE(lock->slock); return (((tmp >> 16) & 0xffff) - (tmp & 0xffff)) > 1; } -static __always_inline void __raw_spin_lock(raw_spinlock_t *lock) +static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock) { int inc = 0x00010000; int tmp; @@ -163,9 +151,7 @@ static __always_inline void __raw_spin_lock(raw_spinlock_t *lock) : "memory", "cc"); } -#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock) - -static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock) +static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock) { int tmp; int new; @@ -187,7 +173,7 @@ static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock) return tmp; } -static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock) +static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock) { asm volatile(UNLOCK_LOCK_PREFIX "incw %0" : "+m" (lock->slock) @@ -196,6 +182,98 @@ static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock) } #endif +#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock) + +#ifdef CONFIG_PARAVIRT +/* + * Define virtualization-friendly old-style lock byte lock, for use in + * pv_lock_ops if desired. + * + * This differs from the pre-2.6.24 spinlock by always using xchgb + * rather than decb to take the lock; this allows it to use a + * zero-initialized lock structure. It also maintains a 1-byte + * contention counter, so that we can implement + * __byte_spin_is_contended. + */ +struct __byte_spinlock { + s8 lock; + s8 spinners; +}; + +static inline int __byte_spin_is_locked(raw_spinlock_t *lock) +{ + struct __byte_spinlock *bl = (struct __byte_spinlock *)lock; + return bl->lock != 0; +} + +static inline int __byte_spin_is_contended(raw_spinlock_t *lock) +{ + struct __byte_spinlock *bl = (struct __byte_spinlock *)lock; + return bl->spinners != 0; +} + +static inline void __byte_spin_lock(raw_spinlock_t *lock) +{ + struct __byte_spinlock *bl = (struct __byte_spinlock *)lock; + s8 val = 1; + + asm("1: xchgb %1, %0\n" + " test %1,%1\n" + " jz 3f\n" + " " LOCK_PREFIX "incb %2\n" + "2: rep;nop\n" + " cmpb $1, %0\n" + " je 2b\n" + " " LOCK_PREFIX "decb %2\n" + " jmp 1b\n" + "3:" + : "+m" (bl->lock), "+q" (val), "+m" (bl->spinners): : "memory"); +} + +static inline int __byte_spin_trylock(raw_spinlock_t *lock) +{ + struct __byte_spinlock *bl = (struct __byte_spinlock *)lock; + u8 old = 1; + + asm("xchgb %1,%0" + : "+m" (bl->lock), "+q" (old) : : "memory"); + + return old == 0; +} + +static inline void __byte_spin_unlock(raw_spinlock_t *lock) +{ + struct __byte_spinlock *bl = (struct __byte_spinlock *)lock; + smp_wmb(); + bl->lock = 0; +} +#else /* !CONFIG_PARAVIRT */ +static inline int __raw_spin_is_locked(raw_spinlock_t *lock) +{ + return __ticket_spin_is_locked(lock); +} + +static inline int __raw_spin_is_contended(raw_spinlock_t *lock) +{ + return __ticket_spin_is_contended(lock); +} + +static __always_inline void __raw_spin_lock(raw_spinlock_t *lock) +{ + __ticket_spin_lock(lock); +} + +static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock) +{ + return __ticket_spin_trylock(lock); +} + +static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock) +{ + __ticket_spin_unlock(lock); +} +#endif /* CONFIG_PARAVIRT */ + static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock) { while (__raw_spin_is_locked(lock))