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 /*-

  * Copyright (c) 2009-2010 Brad Penoff

  * Copyright (c) 2009-2010 Humaira Kamal

  * Copyright (c) 2011-2012 Irene Ruengeler

  * Copyright (c) 2011-2012 Michael Tuexen

  *

  * All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions

  * are met:

  * 1. Redistributions of source code must retain the above copyright

  *    notice, this list of conditions and the following disclaimer.

  * 2. Redistributions in binary form must reproduce the above copyright

  *    notice, this list of conditions and the following disclaimer in the

  *    documentation and/or other materials provided with the distribution.

  *

  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

  * SUCH DAMAGE.

  */

 #ifndef _USER_ATOMIC_H_

 #define _USER_ATOMIC_H_

 /* __Userspace__ version of sys/i386/include/atomic.h goes here */

 /* TODO In the future, might want to not use i386 specific assembly.

  *    The options include:

  *       - implement them generically (but maybe not truly atomic?) in userspace

  *       - have ifdef's for __Userspace_arch_ perhaps (OS isn't enough...)

  */

 #include <stdio.h>

 #include <sys/types.h>

 #if defined(__Userspace_os_Darwin) || defined (__Userspace_os_Windows)

 #if defined (__Userspace_os_Windows)

 #define atomic_add_int(addr, val) InterlockedExchangeAdd((LPLONG)addr, (LONG)val)

 #define atomic_fetchadd_int(addr, val) InterlockedExchangeAdd((LPLONG)addr, (LONG)val)

 #define atomic_subtract_int(addr, val)   InterlockedExchangeAdd((LPLONG)addr,-((LONG)val))

 #define atomic_cmpset_int(dst, exp, src) InterlockedCompareExchange((LPLONG)dst, src, exp)

 #define SCTP_DECREMENT_AND_CHECK_REFCOUNT(addr) (InterlockedExchangeAdd((LPLONG)addr, (-1L)) == 1)

 #else

 #include <libkern/OSAtomic.h>

 #define atomic_add_int(addr, val) OSAtomicAdd32Barrier(val, (int32_t *)addr)

 #define atomic_fetchadd_int(addr, val) OSAtomicAdd32Barrier(val, (int32_t *)addr)

 #define atomic_subtract_int(addr, val) OSAtomicAdd32Barrier(-val, (int32_t *)addr)

 #define atomic_cmpset_int(dst, exp, src) OSAtomicCompareAndSwapIntBarrier(exp, src, (int *)dst)

 #define SCTP_DECREMENT_AND_CHECK_REFCOUNT(addr) (atomic_fetchadd_int(addr, -1) == 0)

 #endif

 #if defined(INVARIANTS)

 #define SCTP_SAVE_ATOMIC_DECREMENT(addr, val) \

 { \

 	int32_t newval; \

 	newval = atomic_fetchadd_int(addr, -val); \

 	if (newval < 0) { \

 		panic("Counter goes negative"); \

 	} \

 }

 #else

 #define SCTP_SAVE_ATOMIC_DECREMENT(addr, val) \

 { \

 	int32_t newval; \

 	newval = atomic_fetchadd_int(addr, -val); \

 	if (newval < 0) { \

 		*addr = 0; \

 	} \

 }

 #if defined(__Userspace_os_Windows)

 static void atomic_init() {} /* empty when we are not using atomic_mtx */

 #else

 static inline void atomic_init() {} /* empty when we are not using atomic_mtx */

 #endif

 #endif

 #else

 /* Using gcc built-in functions for atomic memory operations

    Reference: http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html

    Requires gcc version 4.1.0

    compile with -march=i486

  */

 /*Atomically add V to *P.*/

 #define atomic_add_int(P, V)	 (void) __sync_fetch_and_add(P, V)

 /*Atomically subtrace V from *P.*/

 #define atomic_subtract_int(P, V) (void) __sync_fetch_and_sub(P, V)

 /*

  * Atomically add the value of v to the integer pointed to by p and return

  * the previous value of *p.

  */

 #define atomic_fetchadd_int(p, v) __sync_fetch_and_add(p, v)

 /* Following explanation from src/sys/i386/include/atomic.h,

  * for atomic compare and set

  *

  * if (*dst == exp) *dst = src (all 32 bit words)

  *

  * Returns 0 on failure, non-zero on success

  */

 #define atomic_cmpset_int(dst, exp, src) __sync_bool_compare_and_swap(dst, exp, src)

 #define SCTP_DECREMENT_AND_CHECK_REFCOUNT(addr) (atomic_fetchadd_int(addr, -1) == 1)

 #if defined(INVARIANTS)

 #define SCTP_SAVE_ATOMIC_DECREMENT(addr, val) \

 { \

 	int32_t oldval; \

 	oldval = atomic_fetchadd_int(addr, -val); \

 	if (oldval < val) { \

 		panic("Counter goes negative"); \

 	} \

 }

 #else

 #define SCTP_SAVE_ATOMIC_DECREMENT(addr, val) \

 { \

 	int32_t oldval; \

 	oldval = atomic_fetchadd_int(addr, -val); \

 	if (oldval < val) { \

 		*addr = 0; \

 	} \

 }

 #endif

 static inline void atomic_init() {} /* empty when we are not using atomic_mtx */

 #endif

 #if 0 /* using libatomic_ops */

 #include "user_include/atomic_ops.h"

 /*Atomically add incr to *P, and return the original value of *P.*/

 #define atomic_add_int(P, V)	 AO_fetch_and_add((AO_t*)P, V)

 #define atomic_subtract_int(P, V) AO_fetch_and_add((AO_t*)P, -(V))

 /*

  * Atomically add the value of v to the integer pointed to by p and return

  * the previous value of *p.

  */

 #define atomic_fetchadd_int(p, v) AO_fetch_and_add((AO_t*)p, v)

 /* Atomically compare *addr to old_val, and replace *addr by new_val

    if the first comparison succeeds.  Returns nonzero if the comparison

    succeeded and *addr was updated.

 */

 /* Following Explanation from src/sys/i386/include/atomic.h, which

    matches that of AO_compare_and_swap above.

  * Atomic compare and set, used by the mutex functions

  *

  * if (*dst == exp) *dst = src (all 32 bit words)

  *

  * Returns 0 on failure, non-zero on success

  */

 #define atomic_cmpset_int(dst, exp, src) AO_compare_and_swap((AO_t*)dst, exp, src)

 static inline void atomic_init() {} /* empty when we are not using atomic_mtx */

 #endif /* closing #if for libatomic */

 #if 0 /* using atomic_mtx */

 #include <pthread.h>

 extern userland_mutex_t atomic_mtx;

 #if defined (__Userspace_os_Windows)

 static inline void atomic_init() {

 	InitializeCriticalSection(&atomic_mtx);

 }

 static inline void atomic_destroy() {

 	DeleteCriticalSection(&atomic_mtx);

 }

 static inline void atomic_lock() {

 	EnterCriticalSection(&atomic_mtx);

 }

 static inline void atomic_unlock() {

 	LeaveCriticalSection(&atomic_mtx);

 }

 #else

 static inline void atomic_init() {

 	(void)pthread_mutex_init(&atomic_mtx, NULL);

 }

 static inline void atomic_destroy() {

 	(void)pthread_mutex_destroy(&atomic_mtx);

 }

 static inline void atomic_lock() {

 	(void)pthread_mutex_lock(&atomic_mtx);

 }

 static inline void atomic_unlock() {

 	(void)pthread_mutex_unlock(&atomic_mtx);

 }

 #endif

 /*

  * For userland, always use lock prefixes so that the binaries will run

  * on both SMP and !SMP systems.

  */

 #define	MPLOCKED	"lock ; "

 /*

  * Atomically add the value of v to the integer pointed to by p and return

  * the previous value of *p.

  */

 static __inline u_int

 atomic_fetchadd_int(volatile void *n, u_int v)

 {

 	int *p = (int *) n;

 	atomic_lock();

 	__asm __volatile(

 	"	" MPLOCKED "		"

 	"	xaddl	%0, %1 ;	"

 	"# atomic_fetchadd_int"

 	: "+r" (v),			/* 0 (result) */

 	  "=m" (*p)			/* 1 */

 	: "m" (*p));			/* 2 */

 	atomic_unlock();

 	return (v);

 }

 #ifdef CPU_DISABLE_CMPXCHG

 static __inline int

 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)

 {

 	u_char res;

 	atomic_lock();

 	__asm __volatile(

 	"	pushfl ;		"

 	"	cli ;			"

 	"	cmpl	%3,%4 ;		"

 	"	jne	1f ;		"

 	"	movl	%2,%1 ;		"

 	"1:				"

 	"       sete	%0 ;		"

 	"	popfl ;			"

 	"# atomic_cmpset_int"

 	: "=q" (res),			/* 0 */

 	  "=m" (*dst)			/* 1 */

 	: "r" (src),			/* 2 */

 	  "r" (exp),			/* 3 */

 	  "m" (*dst)			/* 4 */

 	: "memory");

 	atomic_unlock();

 	return (res);

 }

 #else /* !CPU_DISABLE_CMPXCHG */

 static __inline int

 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)

 {

 	atomic_lock();

 	u_char res;

 	__asm __volatile(

 	"	" MPLOCKED "		"

 	"	cmpxchgl %2,%1 ;	"

 	"	sete	%0 ;		"

 	"1:				"

 	"# atomic_cmpset_int"

 	: "=a" (res),			/* 0 */

 	  "=m" (*dst)			/* 1 */

 	: "r" (src),			/* 2 */

 	  "a" (exp),			/* 3 */

 	  "m" (*dst)			/* 4 */

 	: "memory");

 	atomic_unlock();

 	return (res);

 }

 #endif /* CPU_DISABLE_CMPXCHG */

 #define atomic_add_int(P, V)	 do {   \

 		atomic_lock();          \

 		(*(u_int *)(P) += (V)); \

 		atomic_unlock();        \

 } while(0)

 #define atomic_subtract_int(P, V)  do {   \

 		atomic_lock();            \

 		(*(u_int *)(P) -= (V));   \

 		atomic_unlock();          \

 } while(0)

 #endif

 #endif