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-rw-r--r--arch/x86/include/asm/atomic_32.h22
-rw-r--r--arch/x86/lib/atomic64_32.c23
2 files changed, 23 insertions, 22 deletions
diff --git a/arch/x86/include/asm/atomic_32.h b/arch/x86/include/asm/atomic_32.h
index d7c8849b8c67..dc5a667ff791 100644
--- a/arch/x86/include/asm/atomic_32.h
+++ b/arch/x86/include/asm/atomic_32.h
@@ -295,6 +295,28 @@ extern void atomic64_set(atomic64_t *ptr, u64 new_val);
295 * 295 *
296 * Atomically reads the value of @ptr and returns it. 296 * Atomically reads the value of @ptr and returns it.
297 */ 297 */
298static inline u64 atomic64_read(atomic64_t *ptr)
299{
300 u64 res;
301
302 /*
303 * Note, we inline this atomic64_t primitive because
304 * it only clobbers EAX/EDX and leaves the others
305 * untouched. We also (somewhat subtly) rely on the
306 * fact that cmpxchg8b returns the current 64-bit value
307 * of the memory location we are touching:
308 */
309 asm volatile(
310 "mov %%ebx, %%eax\n\t"
311 "mov %%ecx, %%edx\n\t"
312 LOCK_PREFIX "cmpxchg8b %1\n"
313 : "=&A" (res)
314 : "m" (*ptr)
315 );
316
317 return res;
318}
319
298extern u64 atomic64_read(atomic64_t *ptr); 320extern u64 atomic64_read(atomic64_t *ptr);
299 321
300/** 322/**
diff --git a/arch/x86/lib/atomic64_32.c b/arch/x86/lib/atomic64_32.c
index 1d98c9eb6eac..824fa0be55a3 100644
--- a/arch/x86/lib/atomic64_32.c
+++ b/arch/x86/lib/atomic64_32.c
@@ -66,31 +66,10 @@ void atomic64_set(atomic64_t *ptr, u64 new_val)
66{ 66{
67 atomic64_xchg(ptr, new_val); 67 atomic64_xchg(ptr, new_val);
68} 68}
69EXPORT_SYMBOL(atomic64_read); 69EXPORT_SYMBOL(atomic64_set);
70 70
71/** 71/**
72 * atomic64_read - read atomic64 variable
73 * @ptr: pointer to type atomic64_t
74 *
75 * Atomically reads the value of @ptr and returns it.
76 */
77u64 atomic64_read(atomic64_t *ptr)
78{
79 u64 res;
80
81 asm volatile(
82 "mov %%ebx, %%eax\n\t"
83 "mov %%ecx, %%edx\n\t"
84 LOCK_PREFIX "cmpxchg8b %1\n"
85 : "+A" (res)
86 : "m" (*ptr)
87 );
88
89 return res;
90}
91EXPORT_SYMBOL(atomic64_read); 72EXPORT_SYMBOL(atomic64_read);
92
93/**
94 * atomic64_add_return - add and return 73 * atomic64_add_return - add and return
95 * @delta: integer value to add 74 * @delta: integer value to add
96 * @ptr: pointer to type atomic64_t 75 * @ptr: pointer to type atomic64_t