The Tor Browser: netwerk/sctp/src/user_atomic.h@deefc01c0e14 (annotated)

netwerk/sctp/src/user_atomic.h@deefc01c0e14 (annotated)

netwerk/sctp/src/user_atomic.h

Thu, 15 Jan 2015 21:03:48 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 21:03:48 +0100
branch: TOR_BUG_9701
changeset 11: deefc01c0e14
permissions: -rwxr-xr-x

Integrate friendly tips from Tor colleagues to make (or not) 4.5 alpha 3;
This includes removal of overloaded (but unused) methods, and addition of
a overlooked call to DataStruct::SetData(nsISupports, uint32_t, bool.)

 /*-
  * 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

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netwerk/sctp/src/user_atomic.h@deefc01c0e14 (annotated)

netwerk/sctp/src/user_atomic.h