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| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2011-09-28 11:49:28 -0700 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy@goop.org> | 2011-11-25 10:42:59 -0800 |
| commit | 3d94ae0c70a71a9824479366775e2c7679a57d94 (patch) | |
| tree | 041c1013f123fb3177bed6b70375fdc4f6c0ddff | |
| parent | 4a7f340c6a75ec5fca23d9c80a59f3f28cc4a61e (diff) | |
| download | op-kernel-dev-3d94ae0c70a71a9824479366775e2c7679a57d94.zip op-kernel-dev-3d94ae0c70a71a9824479366775e2c7679a57d94.tar.gz | |
x86/cmpxchg: add a locked add() helper
Mostly to remove some conditional code in spinlock.h.
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
| -rw-r--r-- | arch/x86/include/asm/cmpxchg.h | 42 | ||||
| -rw-r--r-- | arch/x86/include/asm/spinlock.h | 15 |
2 files changed, 43 insertions, 14 deletions
diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h index 5d3acdf..49eade1 100644 --- a/arch/x86/include/asm/cmpxchg.h +++ b/arch/x86/include/asm/cmpxchg.h @@ -14,6 +14,8 @@ extern void __cmpxchg_wrong_size(void) __compiletime_error("Bad argument size for cmpxchg"); extern void __xadd_wrong_size(void) __compiletime_error("Bad argument size for xadd"); +extern void __add_wrong_size(void) + __compiletime_error("Bad argument size for add"); /* * Constants for operation sizes. On 32-bit, the 64-bit size it set to @@ -207,4 +209,44 @@ extern void __xadd_wrong_size(void) #define xadd_sync(ptr, inc) __xadd((ptr), (inc), "lock; ") #define xadd_local(ptr, inc) __xadd((ptr), (inc), "") +#define __add(ptr, inc, lock) \ + ({ \ + __typeof__ (*(ptr)) __ret = (inc); \ + switch (sizeof(*(ptr))) { \ + case __X86_CASE_B: \ + asm volatile (lock "addb %b1, %0\n" \ + : "+m" (*(ptr)) : "ri" (inc) \ + : "memory", "cc"); \ + break; \ + case __X86_CASE_W: \ + asm volatile (lock "addw %w1, %0\n" \ + : "+m" (*(ptr)) : "ri" (inc) \ + : "memory", "cc"); \ + break; \ + case __X86_CASE_L: \ + asm volatile (lock "addl %1, %0\n" \ + : "+m" (*(ptr)) : "ri" (inc) \ + : "memory", "cc"); \ + break; \ + case __X86_CASE_Q: \ + asm volatile (lock "addq %1, %0\n" \ + : "+m" (*(ptr)) : "ri" (inc) \ + : "memory", "cc"); \ + break; \ + default: \ + __add_wrong_size(); \ + } \ + __ret; \ + }) + +/* + * add_*() adds "inc" to "*ptr" + * + * __add() takes a lock prefix + * add_smp() is locked when multiple CPUs are online + * add_sync() is always locked + */ +#define add_smp(ptr, inc) __add((ptr), (inc), LOCK_PREFIX) +#define add_sync(ptr, inc) __add((ptr), (inc), "lock; ") + #endif /* ASM_X86_CMPXCHG_H */ diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index 972c260..a82c2bf 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -79,23 +79,10 @@ static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) return cmpxchg(&lock->head_tail, old.head_tail, new.head_tail) == old.head_tail; } -#if (NR_CPUS < 256) static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) { - asm volatile(UNLOCK_LOCK_PREFIX "incb %0" - : "+m" (lock->head_tail) - : - : "memory", "cc"); + __add(&lock->tickets.head, 1, UNLOCK_LOCK_PREFIX); } -#else -static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) -{ - asm volatile(UNLOCK_LOCK_PREFIX "incw %0" - : "+m" (lock->head_tail) - : - : "memory", "cc"); -} -#endif static inline int __ticket_spin_is_locked(arch_spinlock_t *lock) { |
