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Commit 93c9d7f6 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'x86-atomic-for-linus' of... 

Merge branch 'x86-atomic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-atomic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix LOCK_PREFIX_HERE for uniprocessor build
  x86, atomic64: In selftest, distinguish x86-64 from 586+
  x86-32: Fix atomic64_inc_not_zero return value convention
  lib: Fix atomic64_inc_not_zero test
  lib: Fix atomic64_add_unless return value convention
  x86-32: Fix atomic64_add_unless return value convention
  lib: Fix atomic64_add_unless test
  x86: Implement atomic[64]_dec_if_positive()
  lib: Only test atomic64_dec_if_positive on archs having it
  x86-32: Rewrite 32-bit atomic64 functions in assembly
  lib: Add self-test for atomic64_t
  x86-32: Allow UP/SMP lock replacement in cmpxchg64
  x86: Add support for lock prefix in alternatives
parents 7421a10d d9c5841e

arch/x86/include/asm/alternative.h

+6 −3
Original line number Diff line number Diff line
@@ -28,14 +28,17 @@ 
 */



#ifdef CONFIG_SMP

#define LOCK_PREFIX \

#define LOCK_PREFIX_HERE \

		".section .smp_locks,\"a\"\n"	\

		".balign 4\n"			\

		".long 661f - .\n" /* offset */	\

		".long 671f - .\n" /* offset */	\

		".previous\n"			\

		"661:\n\tlock; "

		"671:"



#define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; "



#else /* ! CONFIG_SMP */

#define LOCK_PREFIX_HERE ""

#define LOCK_PREFIX ""

#endif

arch/x86/include/asm/atomic.h

+23 −0
Original line number Diff line number Diff line
@@ -246,6 +246,29 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u) 


#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)



/*

 * atomic_dec_if_positive - decrement by 1 if old value positive

 * @v: pointer of type atomic_t

 *

 * The function returns the old value of *v minus 1, even if

 * the atomic variable, v, was not decremented.

 */

static inline int atomic_dec_if_positive(atomic_t *v)

{

	int c, old, dec;

	c = atomic_read(v);

	for (;;) {

		dec = c - 1;

		if (unlikely(dec < 0))

			break;

		old = atomic_cmpxchg((v), c, dec);

		if (likely(old == c))

			break;

		c = old;

	}

	return dec;

}



/**

 * atomic_inc_short - increment of a short integer

 * @v: pointer to type int

arch/x86/include/asm/atomic64_32.h

+211 −67
Original line number Diff line number Diff line
@@ -14,109 +14,193 @@ typedef struct { 


#define ATOMIC64_INIT(val)	{ (val) }



extern u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val);

#ifdef CONFIG_X86_CMPXCHG64

#define ATOMIC64_ALTERNATIVE_(f, g) "call atomic64_" #g "_cx8"

#else

#define ATOMIC64_ALTERNATIVE_(f, g) ALTERNATIVE("call atomic64_" #f "_386", "call atomic64_" #g "_cx8", X86_FEATURE_CX8)

#endif



#define ATOMIC64_ALTERNATIVE(f) ATOMIC64_ALTERNATIVE_(f, f)



/**

 * atomic64_cmpxchg - cmpxchg atomic64 variable

 * @p: pointer to type atomic64_t

 * @o: expected value

 * @n: new value

 *

 * Atomically sets @v to @n if it was equal to @o and returns

 * the old value.

 */



static inline long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n)

{

	return cmpxchg64(&v->counter, o, n);

}



/**

 * atomic64_xchg - xchg atomic64 variable

 * @ptr:      pointer to type atomic64_t

 * @new_val:  value to assign

 * @v: pointer to type atomic64_t

 * @n: value to assign

 *

 * Atomically xchgs the value of @ptr to @new_val and returns

 * Atomically xchgs the value of @v to @n and returns

 * the old value.

 */

extern u64 atomic64_xchg(atomic64_t *ptr, u64 new_val);

static inline long long atomic64_xchg(atomic64_t *v, long long n)

{

	long long o;

	unsigned high = (unsigned)(n >> 32);

	unsigned low = (unsigned)n;

	asm volatile(ATOMIC64_ALTERNATIVE(xchg)

		     : "=A" (o), "+b" (low), "+c" (high)

		     : "S" (v)

		     : "memory"

		     );

	return o;

}



/**

 * atomic64_set - set atomic64 variable

 * @ptr:      pointer to type atomic64_t

 * @new_val:  value to assign

 * @v: pointer to type atomic64_t

 * @n: value to assign

 *

 * Atomically sets the value of @ptr to @new_val.

 * Atomically sets the value of @v to @n.

 */

extern void atomic64_set(atomic64_t *ptr, u64 new_val);

static inline void atomic64_set(atomic64_t *v, long long i)

{

	unsigned high = (unsigned)(i >> 32);

	unsigned low = (unsigned)i;

	asm volatile(ATOMIC64_ALTERNATIVE(set)

		     : "+b" (low), "+c" (high)

		     : "S" (v)

		     : "eax", "edx", "memory"

		     );

}



/**

 * atomic64_read - read atomic64 variable

 * @ptr:      pointer to type atomic64_t

 * @v: pointer to type atomic64_t

 *

 * Atomically reads the value of @ptr and returns it.

 * Atomically reads the value of @v and returns it.

 */

static inline u64 atomic64_read(atomic64_t *ptr)

static inline long long atomic64_read(atomic64_t *v)

{

	u64 res;



	/*

	 * Note, we inline this atomic64_t primitive because

	 * it only clobbers EAX/EDX and leaves the others

	 * untouched. We also (somewhat subtly) rely on the

	 * fact that cmpxchg8b returns the current 64-bit value

	 * of the memory location we are touching:

	 */

	asm volatile(

		"mov %%ebx, %%eax\n\t"

		"mov %%ecx, %%edx\n\t"

		LOCK_PREFIX "cmpxchg8b %1\n"

			: "=&A" (res)

			: "m" (*ptr)

	long long r;

	asm volatile(ATOMIC64_ALTERNATIVE(read)

		     : "=A" (r), "+c" (v)

		     : : "memory"

		     );



	return res;

	return r;

 }



extern u64 atomic64_read(atomic64_t *ptr);



/**

 * atomic64_add_return - add and return

 * @delta: integer value to add

 * @ptr:   pointer to type atomic64_t

 * @i: integer value to add

 * @v: pointer to type atomic64_t

 *

 * Atomically adds @delta to @ptr and returns @delta + *@ptr

 * Atomically adds @i to @v and returns @i + *@v

 */

extern u64 atomic64_add_return(u64 delta, atomic64_t *ptr);

static inline long long atomic64_add_return(long long i, atomic64_t *v)

{

	asm volatile(ATOMIC64_ALTERNATIVE(add_return)

		     : "+A" (i), "+c" (v)

		     : : "memory"

		     );

	return i;

}



/*

 * Other variants with different arithmetic operators:

 */

extern u64 atomic64_sub_return(u64 delta, atomic64_t *ptr);

extern u64 atomic64_inc_return(atomic64_t *ptr);

extern u64 atomic64_dec_return(atomic64_t *ptr);

static inline long long atomic64_sub_return(long long i, atomic64_t *v)

{

	asm volatile(ATOMIC64_ALTERNATIVE(sub_return)

		     : "+A" (i), "+c" (v)

		     : : "memory"

		     );

	return i;

}



static inline long long atomic64_inc_return(atomic64_t *v)

{

	long long a;

	asm volatile(ATOMIC64_ALTERNATIVE(inc_return)

		     : "=A" (a)

		     : "S" (v)

		     : "memory", "ecx"

		     );

	return a;

}



static inline long long atomic64_dec_return(atomic64_t *v)

{

	long long a;

	asm volatile(ATOMIC64_ALTERNATIVE(dec_return)

		     : "=A" (a)

		     : "S" (v)

		     : "memory", "ecx"

		     );

	return a;

}



/**

 * atomic64_add - add integer to atomic64 variable

 * @delta: integer value to add

 * @ptr:   pointer to type atomic64_t

 * @i: integer value to add

 * @v: pointer to type atomic64_t

 *

 * Atomically adds @delta to @ptr.

 * Atomically adds @i to @v.

 */

extern void atomic64_add(u64 delta, atomic64_t *ptr);

static inline long long atomic64_add(long long i, atomic64_t *v)

{

	asm volatile(ATOMIC64_ALTERNATIVE_(add, add_return)

		     : "+A" (i), "+c" (v)

		     : : "memory"

		     );

	return i;

}



/**

 * atomic64_sub - subtract the atomic64 variable

 * @delta: integer value to subtract

 * @ptr:   pointer to type atomic64_t

 * @i: integer value to subtract

 * @v: pointer to type atomic64_t

 *

 * Atomically subtracts @delta from @ptr.

 * Atomically subtracts @i from @v.

 */

extern void atomic64_sub(u64 delta, atomic64_t *ptr);

static inline long long atomic64_sub(long long i, atomic64_t *v)

{

	asm volatile(ATOMIC64_ALTERNATIVE_(sub, sub_return)

		     : "+A" (i), "+c" (v)

		     : : "memory"

		     );

	return i;

}



/**

 * atomic64_sub_and_test - subtract value from variable and test result

 * @delta: integer value to subtract

 * @ptr:   pointer to type atomic64_t

 * @i: integer value to subtract

 * @v: pointer to type atomic64_t

  *

 * Atomically subtracts @delta from @ptr and returns

 * Atomically subtracts @i from @v and returns

 * true if the result is zero, or false for all

 * other cases.

 */

extern int atomic64_sub_and_test(u64 delta, atomic64_t *ptr);

static inline int atomic64_sub_and_test(long long i, atomic64_t *v)

{

	return atomic64_sub_return(i, v) == 0;

}



/**

 * atomic64_inc - increment atomic64 variable

 * @ptr: pointer to type atomic64_t

 * @v: pointer to type atomic64_t

 *

 * Atomically increments @ptr by 1.

 * Atomically increments @v by 1.

 */

extern void atomic64_inc(atomic64_t *ptr);

static inline void atomic64_inc(atomic64_t *v)

{

	asm volatile(ATOMIC64_ALTERNATIVE_(inc, inc_return)

		     : : "S" (v)

		     : "memory", "eax", "ecx", "edx"

		     );

}



/**

 * atomic64_dec - decrement atomic64 variable
@@ -124,37 +208,97 @@ extern void atomic64_inc(atomic64_t *ptr); 
 *

 * Atomically decrements @ptr by 1.

 */

extern void atomic64_dec(atomic64_t *ptr);

static inline void atomic64_dec(atomic64_t *v)

{

	asm volatile(ATOMIC64_ALTERNATIVE_(dec, dec_return)

		     : : "S" (v)

		     : "memory", "eax", "ecx", "edx"

		     );

}



/**

 * atomic64_dec_and_test - decrement and test

 * @ptr: pointer to type atomic64_t

 * @v: pointer to type atomic64_t

 *

 * Atomically decrements @ptr by 1 and

 * Atomically decrements @v by 1 and

 * returns true if the result is 0, or false for all other

 * cases.

 */

extern int atomic64_dec_and_test(atomic64_t *ptr);

static inline int atomic64_dec_and_test(atomic64_t *v)

{

	return atomic64_dec_return(v) == 0;

}



/**

 * atomic64_inc_and_test - increment and test

 * @ptr: pointer to type atomic64_t

 * @v: pointer to type atomic64_t

 *

 * Atomically increments @ptr by 1

 * Atomically increments @v by 1

 * and returns true if the result is zero, or false for all

 * other cases.

 */

extern int atomic64_inc_and_test(atomic64_t *ptr);

static inline int atomic64_inc_and_test(atomic64_t *v)

{

	return atomic64_inc_return(v) == 0;

}



/**

 * atomic64_add_negative - add and test if negative

 * @delta: integer value to add

 * @ptr:   pointer to type atomic64_t

 * @i: integer value to add

 * @v: pointer to type atomic64_t

 *

 * Atomically adds @delta to @ptr and returns true

 * Atomically adds @i to @v and returns true

 * if the result is negative, or false when

 * result is greater than or equal to zero.

 */

extern int atomic64_add_negative(u64 delta, atomic64_t *ptr);

static inline int atomic64_add_negative(long long i, atomic64_t *v)

{

	return atomic64_add_return(i, v) < 0;

}



/**

 * atomic64_add_unless - add unless the number is a given value

 * @v: pointer of type atomic64_t

 * @a: the amount to add to v...

 * @u: ...unless v is equal to u.

 *

 * Atomically adds @a to @v, so long as it was not @u.

 * Returns non-zero if @v was not @u, and zero otherwise.

 */

static inline int atomic64_add_unless(atomic64_t *v, long long a, long long u)

{

	unsigned low = (unsigned)u;

	unsigned high = (unsigned)(u >> 32);

	asm volatile(ATOMIC64_ALTERNATIVE(add_unless) "\n\t"

		     : "+A" (a), "+c" (v), "+S" (low), "+D" (high)

		     : : "memory");

	return (int)a;

}





static inline int atomic64_inc_not_zero(atomic64_t *v)

{

	int r;

	asm volatile(ATOMIC64_ALTERNATIVE(inc_not_zero)

		     : "=a" (r)

		     : "S" (v)

		     : "ecx", "edx", "memory"

		     );

	return r;

}



static inline long long atomic64_dec_if_positive(atomic64_t *v)

{

	long long r;

	asm volatile(ATOMIC64_ALTERNATIVE(dec_if_positive)

		     : "=A" (r)

		     : "S" (v)

		     : "ecx", "memory"

		     );

	return r;

}



#undef ATOMIC64_ALTERNATIVE

#undef ATOMIC64_ALTERNATIVE_



#endif /* _ASM_X86_ATOMIC64_32_H */

arch/x86/include/asm/atomic64_64.h

+23 −0
Original line number Diff line number Diff line
@@ -221,4 +221,27 @@ static inline int atomic64_add_unless(atomic64_t *v, long a, long u) 


#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)



/*

 * atomic64_dec_if_positive - decrement by 1 if old value positive

 * @v: pointer of type atomic_t

 *

 * The function returns the old value of *v minus 1, even if

 * the atomic variable, v, was not decremented.

 */

static inline long atomic64_dec_if_positive(atomic64_t *v)

{

	long c, old, dec;

	c = atomic64_read(v);

	for (;;) {

		dec = c - 1;

		if (unlikely(dec < 0))

			break;

		old = atomic64_cmpxchg((v), c, dec);

		if (likely(old == c))

			break;

		c = old;

	}

	return dec;

}



#endif /* _ASM_X86_ATOMIC64_64_H */

arch/x86/include/asm/cmpxchg_32.h

+2 −1
Original line number Diff line number Diff line
@@ -271,7 +271,8 @@ extern unsigned long long cmpxchg_486_u64(volatile void *, u64, u64); 
	__typeof__(*(ptr)) __ret;				\

	__typeof__(*(ptr)) __old = (o);				\

	__typeof__(*(ptr)) __new = (n);				\

	alternative_io("call cmpxchg8b_emu",			\

	alternative_io(LOCK_PREFIX_HERE				\

			"call cmpxchg8b_emu",			\

			"lock; cmpxchg8b (%%esi)" ,		\

		       X86_FEATURE_CX8,				\

		       "=A" (__ret),				\