redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

x86: Add xadd helper macro 

Add a common xadd implementation.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Link: http://lkml.kernel.org/r/4E5BCC40.3030501@goop.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
hifive-unleashed-5.1
Jeremy Fitzhardinge 2011-06-21 12:00:55 -07:00 committed by H. Peter Anvin
parent e9826380d8
commit 433b352061
1 changed files with 43 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
arch/x86/include/asm/cmpxchg.h
View File

@ -6,6 +6,7 @@
/* Non-existant functions to indicate usage errors at link time. */
extern void __xchg_wrong_size(void);
extern void __cmpxchg_wrong_size(void);
extern void __xadd_wrong_size(void);
/*
* Constants for operation sizes. On 32-bit, the 64-bit size it set to
@ -157,4 +158,46 @@ extern void __cmpxchg_wrong_size(void);
__cmpxchg_local((ptr), (old), (new), sizeof(*ptr))
#endif
#define __xadd(ptr, inc, lock) \
({ \
__typeof__ (*(ptr)) __ret = (inc); \
switch (sizeof(*(ptr))) { \
case __X86_CASE_B: \
asm volatile (lock "xaddb %b0, %1\n" \
: "+r" (__ret), "+m" (*(ptr)) \
: : "memory", "cc"); \
break; \
case __X86_CASE_W: \
asm volatile (lock "xaddw %w0, %1\n" \
: "+r" (__ret), "+m" (*(ptr)) \
: : "memory", "cc"); \
break; \
case __X86_CASE_L: \
asm volatile (lock "xaddl %0, %1\n" \
: "+r" (__ret), "+m" (*(ptr)) \
: : "memory", "cc"); \
break; \
case __X86_CASE_Q: \
asm volatile (lock "xaddq %q0, %1\n" \
: "+r" (__ret), "+m" (*(ptr)) \
: : "memory", "cc"); \
break; \
default: \
__xadd_wrong_size(); \
} \
__ret; \
})
/*
* xadd() adds "inc" to "*ptr" and atomically returns the previous
* value of "*ptr".
*
* xadd() is locked when multiple CPUs are online
* xadd_sync() is always locked
* xadd_local() is never locked
*/
#define xadd(ptr, inc) __xadd((ptr), (inc), LOCK_PREFIX)
#define xadd_sync(ptr, inc) __xadd((ptr), (inc), "lock; ")
#define xadd_local(ptr, inc) __xadd((ptr), (inc), "")
#endif /* ASM_X86_CMPXCHG_H */