0b2fcfdb8b
Without branch hints, the very unlikely chance of the loop repeating due to cmpxchg failure is unrolled with gcc-4 that I have tested. Improve this for architectures with a native cas/cmpxchg. llsc archs should try to implement this natively. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Andi Kleen <ak@muc.de> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
437 lines
9.6 KiB
C
437 lines
9.6 KiB
C
#ifndef __ARCH_X86_64_ATOMIC__
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#define __ARCH_X86_64_ATOMIC__
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#include <linux/config.h>
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#include <asm/types.h>
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/* atomic_t should be 32 bit signed type */
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/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc..
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*/
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#ifdef CONFIG_SMP
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#define LOCK "lock ; "
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#else
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#define LOCK ""
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#endif
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/*
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* Make sure gcc doesn't try to be clever and move things around
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* on us. We need to use _exactly_ the address the user gave us,
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* not some alias that contains the same information.
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*/
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typedef struct { volatile int counter; } atomic_t;
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#define ATOMIC_INIT(i) { (i) }
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/**
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* atomic_read - read atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically reads the value of @v.
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*/
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#define atomic_read(v) ((v)->counter)
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/**
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* atomic_set - set atomic variable
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* @v: pointer of type atomic_t
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* @i: required value
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*
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* Atomically sets the value of @v to @i.
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*/
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#define atomic_set(v,i) (((v)->counter) = (i))
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/**
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* atomic_add - add integer to atomic variable
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* @i: integer value to add
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* @v: pointer of type atomic_t
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*
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* Atomically adds @i to @v.
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*/
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static __inline__ void atomic_add(int i, atomic_t *v)
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{
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__asm__ __volatile__(
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LOCK "addl %1,%0"
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:"=m" (v->counter)
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:"ir" (i), "m" (v->counter));
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}
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/**
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* atomic_sub - subtract the atomic variable
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v.
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*/
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static __inline__ void atomic_sub(int i, atomic_t *v)
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{
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__asm__ __volatile__(
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LOCK "subl %1,%0"
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:"=m" (v->counter)
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:"ir" (i), "m" (v->counter));
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}
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/**
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* atomic_sub_and_test - subtract value from variable and test result
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v and returns
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* true if the result is zero, or false for all
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* other cases.
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*/
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static __inline__ int atomic_sub_and_test(int i, atomic_t *v)
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{
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unsigned char c;
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__asm__ __volatile__(
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LOCK "subl %2,%0; sete %1"
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:"=m" (v->counter), "=qm" (c)
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:"ir" (i), "m" (v->counter) : "memory");
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return c;
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}
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/**
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* atomic_inc - increment atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1.
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*/
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static __inline__ void atomic_inc(atomic_t *v)
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{
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__asm__ __volatile__(
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LOCK "incl %0"
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:"=m" (v->counter)
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:"m" (v->counter));
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}
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/**
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* atomic_dec - decrement atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1.
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*/
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static __inline__ void atomic_dec(atomic_t *v)
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{
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__asm__ __volatile__(
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LOCK "decl %0"
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:"=m" (v->counter)
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:"m" (v->counter));
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}
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/**
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* atomic_dec_and_test - decrement and test
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1 and
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* returns true if the result is 0, or false for all other
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* cases.
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*/
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static __inline__ int atomic_dec_and_test(atomic_t *v)
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{
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unsigned char c;
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__asm__ __volatile__(
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LOCK "decl %0; sete %1"
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:"=m" (v->counter), "=qm" (c)
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:"m" (v->counter) : "memory");
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return c != 0;
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}
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/**
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* atomic_inc_and_test - increment and test
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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static __inline__ int atomic_inc_and_test(atomic_t *v)
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{
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unsigned char c;
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__asm__ __volatile__(
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LOCK "incl %0; sete %1"
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:"=m" (v->counter), "=qm" (c)
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:"m" (v->counter) : "memory");
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return c != 0;
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}
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/**
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* atomic_add_negative - add and test if negative
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* @i: integer value to add
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* @v: pointer of type atomic_t
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*
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* Atomically adds @i to @v and returns true
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* if the result is negative, or false when
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* result is greater than or equal to zero.
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*/
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static __inline__ int atomic_add_negative(int i, atomic_t *v)
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{
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unsigned char c;
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__asm__ __volatile__(
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LOCK "addl %2,%0; sets %1"
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:"=m" (v->counter), "=qm" (c)
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:"ir" (i), "m" (v->counter) : "memory");
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return c;
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}
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/**
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* atomic_add_return - add and return
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* @i: integer value to add
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* @v: pointer of type atomic_t
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*
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* Atomically adds @i to @v and returns @i + @v
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*/
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static __inline__ int atomic_add_return(int i, atomic_t *v)
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{
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int __i = i;
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__asm__ __volatile__(
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LOCK "xaddl %0, %1;"
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:"=r"(i)
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:"m"(v->counter), "0"(i));
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return i + __i;
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}
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static __inline__ int atomic_sub_return(int i, atomic_t *v)
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{
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return atomic_add_return(-i,v);
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}
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#define atomic_inc_return(v) (atomic_add_return(1,v))
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#define atomic_dec_return(v) (atomic_sub_return(1,v))
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/* An 64bit atomic type */
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typedef struct { volatile long counter; } atomic64_t;
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#define ATOMIC64_INIT(i) { (i) }
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/**
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* atomic64_read - read atomic64 variable
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* @v: pointer of type atomic64_t
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*
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* Atomically reads the value of @v.
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* Doesn't imply a read memory barrier.
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*/
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#define atomic64_read(v) ((v)->counter)
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/**
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* atomic64_set - set atomic64 variable
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* @v: pointer to type atomic64_t
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* @i: required value
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*
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* Atomically sets the value of @v to @i.
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*/
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#define atomic64_set(v,i) (((v)->counter) = (i))
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/**
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* atomic64_add - add integer to atomic64 variable
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* @i: integer value to add
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* @v: pointer to type atomic64_t
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*
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* Atomically adds @i to @v.
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*/
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static __inline__ void atomic64_add(long i, atomic64_t *v)
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{
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__asm__ __volatile__(
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LOCK "addq %1,%0"
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:"=m" (v->counter)
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:"ir" (i), "m" (v->counter));
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}
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/**
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* atomic64_sub - subtract the atomic64 variable
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* @i: integer value to subtract
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* @v: pointer to type atomic64_t
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*
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* Atomically subtracts @i from @v.
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*/
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static __inline__ void atomic64_sub(long i, atomic64_t *v)
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{
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__asm__ __volatile__(
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LOCK "subq %1,%0"
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:"=m" (v->counter)
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:"ir" (i), "m" (v->counter));
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}
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/**
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* atomic64_sub_and_test - subtract value from variable and test result
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* @i: integer value to subtract
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* @v: pointer to type atomic64_t
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*
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* Atomically subtracts @i from @v and returns
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* true if the result is zero, or false for all
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* other cases.
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*/
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static __inline__ int atomic64_sub_and_test(long i, atomic64_t *v)
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{
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unsigned char c;
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__asm__ __volatile__(
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LOCK "subq %2,%0; sete %1"
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:"=m" (v->counter), "=qm" (c)
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:"ir" (i), "m" (v->counter) : "memory");
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return c;
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}
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/**
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* atomic64_inc - increment atomic64 variable
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* @v: pointer to type atomic64_t
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*
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* Atomically increments @v by 1.
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*/
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static __inline__ void atomic64_inc(atomic64_t *v)
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{
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__asm__ __volatile__(
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LOCK "incq %0"
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:"=m" (v->counter)
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:"m" (v->counter));
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}
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/**
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* atomic64_dec - decrement atomic64 variable
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* @v: pointer to type atomic64_t
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*
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* Atomically decrements @v by 1.
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*/
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static __inline__ void atomic64_dec(atomic64_t *v)
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{
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__asm__ __volatile__(
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LOCK "decq %0"
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:"=m" (v->counter)
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:"m" (v->counter));
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}
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/**
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* atomic64_dec_and_test - decrement and test
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* @v: pointer to type atomic64_t
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*
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* Atomically decrements @v by 1 and
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* returns true if the result is 0, or false for all other
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* cases.
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*/
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static __inline__ int atomic64_dec_and_test(atomic64_t *v)
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{
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unsigned char c;
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__asm__ __volatile__(
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LOCK "decq %0; sete %1"
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:"=m" (v->counter), "=qm" (c)
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:"m" (v->counter) : "memory");
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return c != 0;
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}
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/**
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* atomic64_inc_and_test - increment and test
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* @v: pointer to type atomic64_t
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*
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* Atomically increments @v by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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static __inline__ int atomic64_inc_and_test(atomic64_t *v)
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{
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unsigned char c;
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__asm__ __volatile__(
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LOCK "incq %0; sete %1"
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:"=m" (v->counter), "=qm" (c)
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:"m" (v->counter) : "memory");
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return c != 0;
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}
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/**
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* atomic64_add_negative - add and test if negative
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* @i: integer value to add
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* @v: pointer to type atomic64_t
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*
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* Atomically adds @i to @v and returns true
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* if the result is negative, or false when
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* result is greater than or equal to zero.
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*/
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static __inline__ int atomic64_add_negative(long i, atomic64_t *v)
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{
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unsigned char c;
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__asm__ __volatile__(
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LOCK "addq %2,%0; sets %1"
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:"=m" (v->counter), "=qm" (c)
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:"ir" (i), "m" (v->counter) : "memory");
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return c;
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}
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/**
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* atomic64_add_return - add and return
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* @i: integer value to add
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* @v: pointer to type atomic64_t
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*
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* Atomically adds @i to @v and returns @i + @v
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*/
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static __inline__ long atomic64_add_return(long i, atomic64_t *v)
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{
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long __i = i;
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__asm__ __volatile__(
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LOCK "xaddq %0, %1;"
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:"=r"(i)
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:"m"(v->counter), "0"(i));
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return i + __i;
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}
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static __inline__ long atomic64_sub_return(long i, atomic64_t *v)
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{
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return atomic64_add_return(-i,v);
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}
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#define atomic64_inc_return(v) (atomic64_add_return(1,v))
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#define atomic64_dec_return(v) (atomic64_sub_return(1,v))
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#define atomic_cmpxchg(v, old, new) ((int)cmpxchg(&((v)->counter), old, new))
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#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
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/**
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* atomic_add_unless - add unless the number is a given value
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* @v: pointer of type atomic_t
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* @a: the amount to add to v...
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* @u: ...unless v is equal to u.
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*
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* Atomically adds @a to @v, so long as it was not @u.
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* Returns non-zero if @v was not @u, and zero otherwise.
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*/
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#define atomic_add_unless(v, a, u) \
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({ \
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int c, old; \
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c = atomic_read(v); \
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for (;;) { \
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if (unlikely(c == (u))) \
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break; \
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old = atomic_cmpxchg((v), c, c + (a)); \
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if (likely(old == c)) \
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break; \
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c = old; \
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} \
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c != (u); \
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})
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#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
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/* These are x86-specific, used by some header files */
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#define atomic_clear_mask(mask, addr) \
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__asm__ __volatile__(LOCK "andl %0,%1" \
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: : "r" (~(mask)),"m" (*addr) : "memory")
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#define atomic_set_mask(mask, addr) \
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__asm__ __volatile__(LOCK "orl %0,%1" \
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: : "r" ((unsigned)mask),"m" (*(addr)) : "memory")
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/* Atomic operations are already serializing on x86 */
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#define smp_mb__before_atomic_dec() barrier()
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#define smp_mb__after_atomic_dec() barrier()
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#define smp_mb__before_atomic_inc() barrier()
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#define smp_mb__after_atomic_inc() barrier()
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#include <asm-generic/atomic.h>
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#endif
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