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Commit a0752279 authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Linus Torvalds
Browse files

local_t: i386 extension 



Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f43f7b46

include/asm-i386/local.h

+178 −27
Original line number Diff line number Diff line
@@ -2,47 +2,198 @@ 
#define _ARCH_I386_LOCAL_H



#include <linux/percpu.h>

#include <asm/system.h>

#include <asm/atomic.h>



typedef struct

{

	volatile long counter;

	atomic_long_t a;

} local_t;



#define LOCAL_INIT(i)	{ (i) }

#define LOCAL_INIT(i)	{ ATOMIC_LONG_INIT(i) }



#define local_read(v)	((v)->counter)

#define local_set(v,i)	(((v)->counter) = (i))

#define local_read(l)	atomic_long_read(&(l)->a)

#define local_set(l,i)	atomic_long_set(&(l)->a, (i))



static __inline__ void local_inc(local_t *v)

static __inline__ void local_inc(local_t *l)

{

	__asm__ __volatile__(

		"incl %0"

		:"+m" (v->counter));

		:"+m" (l->a.counter));

}



static __inline__ void local_dec(local_t *v)

static __inline__ void local_dec(local_t *l)

{

	__asm__ __volatile__(

		"decl %0"

		:"+m" (v->counter));

		:"+m" (l->a.counter));

}



static __inline__ void local_add(long i, local_t *v)

static __inline__ void local_add(long i, local_t *l)

{

	__asm__ __volatile__(

		"addl %1,%0"

		:"+m" (v->counter)

		:"+m" (l->a.counter)

		:"ir" (i));

}



static __inline__ void local_sub(long i, local_t *v)

static __inline__ void local_sub(long i, local_t *l)

{

	__asm__ __volatile__(

		"subl %1,%0"

		:"+m" (v->counter)

		:"+m" (l->a.counter)

		:"ir" (i));

}



/**

 * local_sub_and_test - subtract value from variable and test result

 * @i: integer value to subtract

 * @l: pointer of type local_t

 *

 * Atomically subtracts @i from @l and returns

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

 * other cases.

 */

static __inline__ int local_sub_and_test(long i, local_t *l)

{

	unsigned char c;



	__asm__ __volatile__(

		"subl %2,%0; sete %1"

		:"+m" (l->a.counter), "=qm" (c)

		:"ir" (i) : "memory");

	return c;

}



/**

 * local_dec_and_test - decrement and test

 * @l: pointer of type local_t

 *

 * Atomically decrements @l by 1 and

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

 * cases.

 */

static __inline__ int local_dec_and_test(local_t *l)

{

	unsigned char c;



	__asm__ __volatile__(

		"decl %0; sete %1"

		:"+m" (l->a.counter), "=qm" (c)

		: : "memory");

	return c != 0;

}



/**

 * local_inc_and_test - increment and test

 * @l: pointer of type local_t

 *

 * Atomically increments @l by 1

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

 * other cases.

 */

static __inline__ int local_inc_and_test(local_t *l)

{

	unsigned char c;



	__asm__ __volatile__(

		"incl %0; sete %1"

		:"+m" (l->a.counter), "=qm" (c)

		: : "memory");

	return c != 0;

}



/**

 * local_add_negative - add and test if negative

 * @l: pointer of type local_t

 * @i: integer value to add

 *

 * Atomically adds @i to @l and returns true

 * if the result is negative, or false when

 * result is greater than or equal to zero.

 */

static __inline__ int local_add_negative(long i, local_t *l)

{

	unsigned char c;



	__asm__ __volatile__(

		"addl %2,%0; sets %1"

		:"+m" (l->a.counter), "=qm" (c)

		:"ir" (i) : "memory");

	return c;

}



/**

 * local_add_return - add and return

 * @l: pointer of type local_t

 * @i: integer value to add

 *

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

 */

static __inline__ long local_add_return(long i, local_t *l)

{

	long __i;

#ifdef CONFIG_M386

	unsigned long flags;

	if(unlikely(boot_cpu_data.x86==3))

		goto no_xadd;

#endif

	/* Modern 486+ processor */

	__i = i;

	__asm__ __volatile__(

		"xaddl %0, %1;"

		:"+r" (i), "+m" (l->a.counter)

		: : "memory");

	return i + __i;



#ifdef CONFIG_M386

no_xadd: /* Legacy 386 processor */

	local_irq_save(flags);

	__i = local_read(l);

	local_set(l, i + __i);

	local_irq_restore(flags);

	return i + __i;

#endif

}



static __inline__ long local_sub_return(long i, local_t *l)

{

	return local_add_return(-i,l);

}



#define local_inc_return(l)  (local_add_return(1,l))

#define local_dec_return(l)  (local_sub_return(1,l))



#define local_cmpxchg(l, o, n) \

	(cmpxchg_local(&((l)->a.counter), (o), (n)))

/* Always has a lock prefix */

#define local_xchg(l, n) (xchg(&((l)->a.counter), (n)))



/**

 * local_add_unless - add unless the number is a given value

 * @l: pointer of type local_t

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

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

 *

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

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

 */

#define local_add_unless(l, a, u)				\

({								\

	long c, old;						\

	c = local_read(l);					\

	for (;;) {						\

		if (unlikely(c == (u)))				\

			break;					\

		old = local_cmpxchg((l), c, c + (a));	\

		if (likely(old == c))				\

			break;					\

		c = old;					\

	}							\

	c != (u);						\

})

#define local_inc_not_zero(l) local_add_unless((l), 1, 0)



/* On x86, these are no better than the atomic variants. */

#define __local_inc(l)		local_inc(l)

#define __local_dec(l)		local_dec(l)
@@ -56,27 +207,27 @@ static __inline__ void local_sub(long i, local_t *v) 


/* Need to disable preemption for the cpu local counters otherwise we could

   still access a variable of a previous CPU in a non atomic way. */

#define cpu_local_wrap_v(v)	 	\

#define cpu_local_wrap_v(l)	 	\

	({ local_t res__;		\

	   preempt_disable(); 		\

	   res__ = (v);			\

	   res__ = (l);			\

	   preempt_enable();		\

	   res__; })

#define cpu_local_wrap(v)		\

#define cpu_local_wrap(l)		\

	({ preempt_disable();		\

	   v;				\

	   l;				\

	   preempt_enable(); })		\



#define cpu_local_read(v)    cpu_local_wrap_v(local_read(&__get_cpu_var(v)))

#define cpu_local_set(v, i)  cpu_local_wrap(local_set(&__get_cpu_var(v), (i)))

#define cpu_local_inc(v)     cpu_local_wrap(local_inc(&__get_cpu_var(v)))

#define cpu_local_dec(v)     cpu_local_wrap(local_dec(&__get_cpu_var(v)))

#define cpu_local_add(i, v)  cpu_local_wrap(local_add((i), &__get_cpu_var(v)))

#define cpu_local_sub(i, v)  cpu_local_wrap(local_sub((i), &__get_cpu_var(v)))



#define __cpu_local_inc(v)	cpu_local_inc(v)

#define __cpu_local_dec(v)	cpu_local_dec(v)

#define __cpu_local_add(i, v)	cpu_local_add((i), (v))

#define __cpu_local_sub(i, v)	cpu_local_sub((i), (v))

#define cpu_local_read(l)    cpu_local_wrap_v(local_read(&__get_cpu_var(l)))

#define cpu_local_set(l, i)  cpu_local_wrap(local_set(&__get_cpu_var(l), (i)))

#define cpu_local_inc(l)     cpu_local_wrap(local_inc(&__get_cpu_var(l)))

#define cpu_local_dec(l)     cpu_local_wrap(local_dec(&__get_cpu_var(l)))

#define cpu_local_add(i, l)  cpu_local_wrap(local_add((i), &__get_cpu_var(l)))

#define cpu_local_sub(i, l)  cpu_local_wrap(local_sub((i), &__get_cpu_var(l)))



#define __cpu_local_inc(l)	cpu_local_inc(l)

#define __cpu_local_dec(l)	cpu_local_dec(l)

#define __cpu_local_add(i, l)	cpu_local_add((i), (l))

#define __cpu_local_sub(i, l)	cpu_local_sub((i), (l))



#endif /* _ARCH_I386_LOCAL_H */

include/asm-i386/system.h

+58 −1
Original line number Diff line number Diff line
@@ -305,6 +305,9 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz 
#define sync_cmpxchg(ptr,o,n)\

	((__typeof__(*(ptr)))__sync_cmpxchg((ptr),(unsigned long)(o),\

					(unsigned long)(n),sizeof(*(ptr))))

#define cmpxchg_local(ptr,o,n)\

	((__typeof__(*(ptr)))__cmpxchg_local((ptr),(unsigned long)(o),\

					(unsigned long)(n),sizeof(*(ptr))))

#endif



static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
@@ -367,6 +370,33 @@ static inline unsigned long __sync_cmpxchg(volatile void *ptr, 
	return old;

}



static inline unsigned long __cmpxchg_local(volatile void *ptr,

			unsigned long old, unsigned long new, int size)

{

	unsigned long prev;

	switch (size) {

	case 1:

		__asm__ __volatile__("cmpxchgb %b1,%2"

				     : "=a"(prev)

				     : "q"(new), "m"(*__xg(ptr)), "0"(old)

				     : "memory");

		return prev;

	case 2:

		__asm__ __volatile__("cmpxchgw %w1,%2"

				     : "=a"(prev)

				     : "r"(new), "m"(*__xg(ptr)), "0"(old)

				     : "memory");

		return prev;

	case 4:

		__asm__ __volatile__("cmpxchgl %1,%2"

				     : "=a"(prev)

				     : "r"(new), "m"(*__xg(ptr)), "0"(old)

				     : "memory");

		return prev;

	}

	return old;

}



#ifndef CONFIG_X86_CMPXCHG

/*

 * Building a kernel capable running on 80386. It may be necessary to
@@ -403,6 +433,17 @@ static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old, 
					(unsigned long)(n), sizeof(*(ptr))); \

	__ret;								\

})

#define cmpxchg_local(ptr,o,n)						\

({									\

	__typeof__(*(ptr)) __ret;					\

	if (likely(boot_cpu_data.x86 > 3))				\

		__ret = __cmpxchg_local((ptr), (unsigned long)(o),	\

					(unsigned long)(n), sizeof(*(ptr))); \

	else								\

		__ret = cmpxchg_386((ptr), (unsigned long)(o),		\

					(unsigned long)(n), sizeof(*(ptr))); \

	__ret;								\

})

#endif



#ifdef CONFIG_X86_CMPXCHG64
@@ -421,10 +462,26 @@ static inline unsigned long long __cmpxchg64(volatile void *ptr, unsigned long l 
	return prev;

}



static inline unsigned long long __cmpxchg64_local(volatile void *ptr,

			unsigned long long old, unsigned long long new)

{

	unsigned long long prev;

	__asm__ __volatile__("cmpxchg8b %3"

			     : "=A"(prev)

			     : "b"((unsigned long)new),

			       "c"((unsigned long)(new >> 32)),

			       "m"(*__xg(ptr)),

			       "0"(old)

			     : "memory");

	return prev;

}



#define cmpxchg64(ptr,o,n)\

	((__typeof__(*(ptr)))__cmpxchg64((ptr),(unsigned long long)(o),\

					(unsigned long long)(n)))



#define cmpxchg64_local(ptr,o,n)\

	((__typeof__(*(ptr)))__cmpxchg64_local((ptr),(unsigned long long)(o),\

					(unsigned long long)(n)))

#endif

    

/*