atomic/atomic_unknown.h
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 /* 
  * Copyright (C) 2006 iptelorg GmbH
  *
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  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
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  *
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  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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  */
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 /**
  * @file
  * @brief Atomic operations and memory barriers implemented using locks
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  *
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  * Atomic operations and memory barriers implemented using locks
  * (for architectures not yet supported via inline assembler).
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  *
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  * \warning atomic ops do not include memory barriers, see atomic_ops.h
  * for more details 
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  *
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  * Config defines:
  * - NOSMP (membars are null in this case)
  * - HAVE_ASM_INLINE_MEMBAR (membars already defined => use them)
  * - HAVE_ASM_INLINE_ATOMIC_OPS (atomic ops already defined => don't
  *   redefine them)
  * @ingroup atomic
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  */
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 /* 
  * History:
  * --------
  *  2006-03-08  created by andrei
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  *  2007-05-11  added atomic_add and atomic_cmpxchg 
  *              use lock_set if lock economy is not needed (andrei)
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  *  2007-05-29  added membar_depends(), membar_*_atomic_op and
  *                membar_*_atomic_setget (andrei)
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  */
 
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 #ifndef _atomic_unknown_h
 #define _atomic_unknown_h
 
 #include "../lock_ops.h"
 
 
 
 #ifndef HAVE_ASM_INLINE_MEMBAR
 
 #ifdef NOSMP
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 #define membar() do {} while(0)
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 #else /* SMP */
 
 #warning no native memory barrier implementations, falling back to slow lock \
 	       based workarround
 
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 #define MEMBAR_USES_LOCK
 
 extern gen_lock_t* __membar_lock; /* init in atomic_ops.c */
 #define _membar_lock    lock_get(__membar_lock)
 #define _membar_unlock  lock_release(__membar_lock)
 
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 /* memory barriers 
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  *  not a known cpu -> fall back unlock/lock: safe but costly  (it should 
  *  include a memory barrier effect)
  *  lock/unlock does not imply a full memory barrier effect (it allows mixing
  *   operations from before the lock with operations after the lock _inside_
  *  the lock & unlock block; however in most implementations it is equivalent
  *  with at least membar StoreStore | StoreLoad | LoadStore => only LoadLoad
  *  is missing). On the other hand and unlock/lock will always be equivalent
  *  with a full memory barrier
  *  => to be safe we must use either unlock; lock or lock; unlock; lock; unlock
  *  --andrei*/
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 #define membar() \
 	do{\
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 		_membar_unlock; \
 		_membar_lock; \
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 	} while(0)
 #endif /* NOSMP */
 
 
 #define membar_write() membar()
 
 #define membar_read()  membar()
 
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 #ifndef __CPU_alpha
 #define membar_depends()  do {} while(0) /* really empty, not even a cc bar. */
 #else
 /* really slow */
 #define membar_depends()  membar_read()
 #endif
 
 #define membar_enter_lock() do {} while(0)
 #define membar_leave_lock() do {} while(0)
 
 /* membars after or before atomic_ops or atomic_setget -> use these or
  *  mb_<atomic_op_name>() if you need a memory barrier in one of these
  *  situations (on some archs where the atomic operations imply memory
  *   barriers is better to use atomic_op_x(); membar_atomic_op() then
  *    atomic_op_x(); membar()) */
 #define membar_atomic_op()				membar()
 #define membar_atomic_setget()			membar()
 #define membar_write_atomic_op()		membar_write()
 #define membar_write_atomic_setget()	membar_write()
 #define membar_read_atomic_op()			membar_read()
 #define membar_read_atomic_setget()		membar_read()
 
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 #endif /* HAVE_ASM_INLINE_MEMBAR */
 
 
 #ifndef HAVE_ASM_INLINE_ATOMIC_OPS
 
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 #ifdef GEN_LOCK_SET_T_UNLIMITED
 #ifndef ATOMIC_OPS_USE_LOCK_SET
 #define ATOMIC_OPS_USE_LOCK_SET
 #endif
 #else
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 #ifndef ATOMIC_OPS_USE_LOCK
 #define ATOMIC_OPS_USE_LOCK
 #endif
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 #endif /* GEN_LOCK_SET_T_UNLIMITED */
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 #ifdef ATOMIC_OPS_USE_LOCK_SET 
 #define _ATOMIC_LS_SIZE	256
 /* hash after the variable address: ignore first 4 bits since
  * vars are generally alloc'ed at at least 16 bytes multiples */
 #define _atomic_ls_hash(v)  ((((unsigned long)(v))>>4)&(_ATOMIC_LS_SIZE-1))
 extern gen_lock_set_t* _atomic_lock_set;
 
 #define atomic_lock(v)   lock_set_get(_atomic_lock_set, _atomic_ls_hash(v))
 #define atomic_unlock(v) lock_set_release(_atomic_lock_set, _atomic_ls_hash(v))
 
 #else
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 extern gen_lock_t* _atomic_lock; /* declared and init in ../atomic_ops.c */
 
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 #define atomic_lock(v)    lock_get(_atomic_lock)
 #define atomic_unlock(v)  lock_release(_atomic_lock)
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 #endif /* ATOMIC_OPS_USE_LOCK_SET */
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 /* atomic ops */
 
 
 /* OP can include var (function param), no other var. is declared */
 #define ATOMIC_FUNC_DECL(NAME, OP, P_TYPE, RET_TYPE, RET_EXPR) \
 	inline static RET_TYPE atomic_##NAME##_##P_TYPE (volatile P_TYPE *var) \
 	{ \
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 		atomic_lock(var); \
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 		OP ; \
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 		atomic_unlock(var); \
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 		return RET_EXPR; \
 	}
 
 
 /* like above, but takes an extra param: v =>
  *  OP can use var and v (function params) */
 #define ATOMIC_FUNC_DECL1(NAME, OP, P_TYPE, RET_TYPE, RET_EXPR) \
 	inline static RET_TYPE atomic_##NAME##_##P_TYPE (volatile P_TYPE *var, \
 														P_TYPE v) \
 	{ \
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 		atomic_lock(var); \
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 		OP ; \
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 		atomic_unlock(var); \
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 		return RET_EXPR; \
 	}
 
 /* OP can include var (function param), and ret (return)
  *  ( like ATOMIC_FUNC_DECL, but includes ret) */
 #define ATOMIC_FUNC_DECL_RET(NAME, OP, P_TYPE, RET_TYPE, RET_EXPR) \
 	inline static RET_TYPE atomic_##NAME##_##P_TYPE (volatile P_TYPE *var) \
 	{ \
 		P_TYPE ret; \
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 		atomic_lock(var); \
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 		OP ; \
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 		atomic_unlock(var); \
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 		return RET_EXPR; \
 	}
 
 /* like ATOMIC_FUNC_DECL1, but declares an extra variable: P_TYPE ret */
 #define ATOMIC_FUNC_DECL1_RET(NAME, OP, P_TYPE, RET_TYPE, RET_EXPR) \
 	inline static RET_TYPE atomic_##NAME##_##P_TYPE (volatile P_TYPE *var, \
 														P_TYPE v) \
 	{ \
 		P_TYPE ret; \
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 		atomic_lock(var); \
 		OP ; \
 		atomic_unlock(var); \
 		return RET_EXPR; \
 	}
 
 /* like ATOMIC_FUNC_DECL1_RET, but takes an extra param */
 #define ATOMIC_FUNC_DECL2_RET(NAME, OP, P_TYPE, RET_TYPE, RET_EXPR) \
 	inline static RET_TYPE atomic_##NAME##_##P_TYPE (volatile P_TYPE *var, \
 														P_TYPE v1, P_TYPE v2)\
 	{ \
 		P_TYPE ret; \
 		atomic_lock(var); \
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 		OP ; \
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 		atomic_unlock(var); \
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 		return RET_EXPR; \
 	}
 
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 ATOMIC_FUNC_DECL(inc,      (*var)++, int, void, /* no return */ )
 ATOMIC_FUNC_DECL(dec,      (*var)--, int, void, /* no return */ )
 ATOMIC_FUNC_DECL1(and,     *var&=v, int, void, /* no return */ )
 ATOMIC_FUNC_DECL1(or,      *var|=v, int, void, /* no return */ )
 ATOMIC_FUNC_DECL_RET(inc_and_test, ret=++(*var), int, int, (ret==0) )
 ATOMIC_FUNC_DECL_RET(dec_and_test, ret=--(*var), int, int, (ret==0) )
 ATOMIC_FUNC_DECL1_RET(get_and_set, ret=*var;*var=v , int, int,  ret)
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 ATOMIC_FUNC_DECL2_RET(cmpxchg, ret=*var;\
 							*var=(((ret!=v1)-1)&v2)+(~((ret!=v1)-1)&ret),\
 							int, int,  ret)
 ATOMIC_FUNC_DECL1_RET(add, *var+=v;ret=*var, int, int, ret )
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 ATOMIC_FUNC_DECL(inc,      (*var)++, long, void, /* no return */ )
 ATOMIC_FUNC_DECL(dec,      (*var)--, long, void, /* no return */ )
 ATOMIC_FUNC_DECL1(and,     *var&=v, long, void, /* no return */ )
 ATOMIC_FUNC_DECL1(or,      *var|=v, long, void, /* no return */ )
 ATOMIC_FUNC_DECL_RET(inc_and_test, ret=++(*var), long, long, (ret==0) )
 ATOMIC_FUNC_DECL_RET(dec_and_test, ret=--(*var), long, long, (ret==0) )
 ATOMIC_FUNC_DECL1_RET(get_and_set, ret=*var;*var=v , long, long,  ret)
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 ATOMIC_FUNC_DECL2_RET(cmpxchg, ret=*var;\
 							*var=(((ret!=v1)-1)&v2)+(~((ret!=v1)-1)&ret),\
 							long, long,  ret)
 ATOMIC_FUNC_DECL1_RET(add, *var+=v;ret=*var, long, long, ret )
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 #define atomic_inc(var) atomic_inc_int(&(var)->val)
 #define atomic_dec(var) atomic_dec_int(&(var)->val)
 #define atomic_and(var, mask) atomic_and_int(&(var)->val, (mask))
 #define atomic_or(var, mask)  atomic_or_int(&(var)->val, (mask))
 #define atomic_dec_and_test(var) atomic_dec_and_test_int(&(var)->val)
 #define atomic_inc_and_test(var) atomic_inc_and_test_int(&(var)->val)
 #define atomic_get_and_set(var, i) atomic_get_and_set_int(&(var)->val, i)
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 #define atomic_cmpxchg(var, old, new_v) \
 	atomic_cmpxchg_int(&(var)->val, old, new_v)
 #define atomic_add(var, v) atomic_add_int(&(var)->val, v)
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 /* memory barrier versions, the same as "normal" versions (since the
  *  locks act as membars), *  except fot * the set/get 
  */
 
 /* mb_atomic_{set,get} use membar() : if we're lucky we have membars
  * for the arch. (e.g. sparc32) => membar() might be cheaper then lock/unlock */
 #define mb_atomic_set_int(v, i) \
 	do{ \
 		membar(); \
 		atomic_set_int(v, i); \
 	}while(0)
 
 inline static int  mb_atomic_get_int(volatile int* v)
 {
 		membar();
 		return atomic_get_int(v);
 }
 
 
 #define mb_atomic_set_long(v, i) \
 	do{ \
 		membar(); \
 		atomic_set_long(v, i); \
 	}while(0)
 
 inline static long mb_atomic_get_long(volatile long* v)
 {
 		membar();
 		return atomic_get_long(v);
 }
 
 
 /* the rest are the same as the non membar version (the locks have a membar
  * effect) */
 #define mb_atomic_inc_int(v)	atomic_inc_int(v)
 #define mb_atomic_dec_int(v)	atomic_dec_int(v)
 #define mb_atomic_or_int(v, m)	atomic_or_int(v, m)
 #define mb_atomic_and_int(v, m)	atomic_and_int(v, m)
 #define mb_atomic_inc_and_test_int(v)	atomic_inc_and_test_int(v)
 #define mb_atomic_dec_and_test_int(v)	atomic_dec_and_test_int(v)
 #define mb_atomic_get_and_set_int(v, i)	atomic_get_and_set_int(v, i)
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 #define mb_atomic_cmpxchg_int(v, o, n)	atomic_cmpxchg_int(v, o, n)
 #define mb_atomic_add_int(v, i)	atomic_add_int(v, i)
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 #define mb_atomic_inc_long(v)	atomic_inc_long(v)
 #define mb_atomic_dec_long(v)	atomic_dec_long(v)
 #define mb_atomic_or_long(v, m)	atomic_or_long(v, m)
 #define mb_atomic_and_long(v, m)	atomic_and_long(v, m)
 #define mb_atomic_inc_and_test_long(v)	atomic_inc_and_test_long(v)
 #define mb_atomic_dec_and_test_long(v)	atomic_dec_and_test_long(v)
 #define mb_atomic_get_and_set_long(v, i)	atomic_get_and_set_long(v, i)
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 #define mb_atomic_cmpxchg_long(v, o, n)	atomic_cmpxchg_long(v, o, n)
 #define mb_atomic_add_long(v, i)	atomic_add_long(v, i)
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 #define mb_atomic_inc(var) mb_atomic_inc_int(&(var)->val)
 #define mb_atomic_dec(var) mb_atomic_dec_int(&(var)->val)
 #define mb_atomic_and(var, mask) mb_atomic_and_int(&(var)->val, (mask))
 #define mb_atomic_or(var, mask)  mb_atomic_or_int(&(var)->val, (mask))
 #define mb_atomic_dec_and_test(var) mb_atomic_dec_and_test_int(&(var)->val)
 #define mb_atomic_inc_and_test(var) mb_atomic_inc_and_test_int(&(var)->val)
 #define mb_atomic_get_and_set(var, i) mb_atomic_get_and_set_int(&(var)->val, i)
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 #define mb_atomic_cmpxchg(v, o, n)	atomic_cmpxchg_int(&(v)->val, o, n)
 #define mb_atomic_add(v, i)	atomic_add_int(&(v)->val, i)
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 #define mb_atomic_get(var)	mb_atomic_get_int(&(var)->val)
 #define mb_atomic_set(var, i)	mb_atomic_set_int(&(var)->val, i)
 
 #endif /* if HAVE_ASM_INLINE_ATOMIC_OPS */
 
 #endif