mirror of
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Implement atomic_swap() and atomic_testandset().
Reviewed by: arch, bde, jilles, kib
This commit is contained in:
Jung-uk Kim
parent
8e0cf70b5d
commit
8a1ee2d346
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=254617
@ -23,7 +23,7 @@
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.\"
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.\" $FreeBSD$
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.\"
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.Dd September 27, 2005
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.Dd August 20, 2013
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.Dt ATOMIC 9
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.Os
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.Sh NAME
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@ -62,6 +62,10 @@
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.Fn atomic_subtract_[acq_|rel_]<type> "volatile <type> *p" "<type> v"
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.Ft void
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.Fn atomic_store_rel_<type> "volatile <type> *p" "<type> v"
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.Ft <type>
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.Fn atomic_swap_<type> "volatile <type> *p" "<type> v"
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.Ft int
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.Fn atomic_testandset_<type> "volatile <type> *p" "u_int v"
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.Sh DESCRIPTION
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Each of the atomic operations is guaranteed to be atomic in the presence of
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interrupts.
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@ -184,9 +188,9 @@ This section describes the semantics of each operation using a C like notation.
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.Bd -literal -compact
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if (*dst == old) {
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*dst = new;
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return 1;
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return (1);
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} else
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return 0;
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return (0);
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.Ed
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.El
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.Pp
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@ -203,7 +207,7 @@ and
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.Bd -literal -compact
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tmp = *p;
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*p += v;
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return tmp;
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return (tmp);
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.Ed
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.El
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.Pp
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@ -216,9 +220,9 @@ and
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.Dq Li 32
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and do not have any variants with memory barriers at this time.
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.Bl -hang
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.It Fn atomic_load addr
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.It Fn atomic_load p
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.Bd -literal -compact
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return (*addr)
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return (*p);
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.Ed
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.El
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.Pp
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@ -226,11 +230,11 @@ The
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.Fn atomic_load
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functions are only provided with acquire memory barriers.
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.Bl -hang
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.It Fn atomic_readandclear addr
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.It Fn atomic_readandclear p
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.Bd -literal -compact
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temp = *addr;
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*addr = 0;
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return (temp);
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tmp = *p;
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*p = 0;
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return (tmp);
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.Ed
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.El
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.Pp
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@ -243,8 +247,7 @@ functions are not implemented for the types
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.Dq Li 8 ,
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and
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.Dq Li 16
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and do
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not have any variants with memory barriers at this time.
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and do not have any variants with memory barriers at this time.
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.Bl -hang
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.It Fn atomic_set p v
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.Bd -literal -compact
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@ -264,6 +267,44 @@ The
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.Fn atomic_store
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functions are only provided with release memory barriers.
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.Pp
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.Bl -hang
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.It Fn atomic_swap p v
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.Bd -literal -compact
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tmp = *p;
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*p = v;
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return (tmp);
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.Ed
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.El
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.Pp
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The
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.Fn atomic_swap
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functions are not implemented for the types
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.Dq Li char ,
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.Dq Li short ,
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.Dq Li ptr ,
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.Dq Li 8 ,
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and
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.Dq Li 16
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and do not have any variants with memory barriers at this time.
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.Bl -hang
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.It Fn atomic_testandset p v
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.Bd -literal -compact
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bit = 1 << (v % (sizeof(*p) * NBBY));
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tmp = (*p & bit) != 0;
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*p |= bit;
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return (tmp);
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.Ed
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.El
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.Pp
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The
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.Fn atomic_testandset
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functions are only implemented for the types
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.Dq Li int ,
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.Dq Li long
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and
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.Dq Li 32
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and do not have any variants with memory barriers at this time.
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.Pp
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The type
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.Dq Li 64
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is currently not implemented for any of the atomic operations on the
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@ -275,15 +316,17 @@ architectures.
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.Sh RETURN VALUES
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The
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.Fn atomic_cmpset
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function
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returns the result of the compare operation.
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function returns the result of the compare operation.
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The
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.Fn atomic_fetchadd ,
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.Fn atomic_load ,
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.Fn atomic_readandclear ,
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and
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.Fn atomic_readandclear
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functions
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return the value at the specified address.
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.Fn atomic_swap
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functions return the value at the specified address.
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The
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.Fn atomic_testandset
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function returns the result of the test operation.
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.Sh EXAMPLES
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This example uses the
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.Fn atomic_cmpset_acq_ptr
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@ -354,3 +397,9 @@ The
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.Fn atomic_fetchadd
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operations were added in
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.Fx 6.0 .
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The
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.Fn atomic_swap
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and
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.Fn atomic_testandset
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operations were added in
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.Fx 10.0 .
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@ -54,12 +54,14 @@
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* atomic_clear_int(P, V) (*(u_int *)(P) &= ~(V))
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* atomic_add_int(P, V) (*(u_int *)(P) += (V))
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* atomic_subtract_int(P, V) (*(u_int *)(P) -= (V))
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* atomic_swap_int(P, V) (return (*(u_int *)(P)); *(u_int *)(P) = (V);)
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* atomic_readandclear_int(P) (return (*(u_int *)(P)); *(u_int *)(P) = 0;)
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*
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* atomic_set_long(P, V) (*(u_long *)(P) |= (V))
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* atomic_clear_long(P, V) (*(u_long *)(P) &= ~(V))
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* atomic_add_long(P, V) (*(u_long *)(P) += (V))
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* atomic_subtract_long(P, V) (*(u_long *)(P) -= (V))
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* atomic_swap_long(P, V) (return (*(u_long *)(P)); *(u_long *)(P) = (V);)
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* atomic_readandclear_long(P) (return (*(u_long *)(P)); *(u_long *)(P) = 0;)
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*/
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@ -80,6 +82,8 @@ int atomic_cmpset_int(volatile u_int *dst, u_int expect, u_int src);
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int atomic_cmpset_long(volatile u_long *dst, u_long expect, u_long src);
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u_int atomic_fetchadd_int(volatile u_int *p, u_int v);
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u_long atomic_fetchadd_long(volatile u_long *p, u_long v);
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int atomic_testandset_int(volatile u_int *p, u_int v);
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int atomic_testandset_long(volatile u_long *p, u_int v);
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#define ATOMIC_LOAD(TYPE, LOP) \
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u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p)
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@ -205,6 +209,40 @@ atomic_fetchadd_long(volatile u_long *p, u_long v)
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return (v);
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}
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static __inline int
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atomic_testandset_int(volatile u_int *p, u_int v)
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{
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u_char res;
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__asm __volatile(
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" " MPLOCKED " "
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" btsl %2,%1 ; "
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" setc %0 ; "
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"# atomic_testandset_int"
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: "=q" (res), /* 0 */
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"+m" (*p) /* 1 */
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: "Ir" (v & 0x1f) /* 2 */
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: "cc");
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return (res);
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}
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static __inline int
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atomic_testandset_long(volatile u_long *p, u_int v)
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{
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u_char res;
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__asm __volatile(
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" " MPLOCKED " "
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" btsq %2,%1 ; "
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" setc %0 ; "
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"# atomic_testandset_long"
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: "=q" (res), /* 0 */
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"+m" (*p) /* 1 */
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: "Jr" ((u_long)(v & 0x3f)) /* 2 */
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: "cc");
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return (res);
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}
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/*
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* We assume that a = b will do atomic loads and stores. Due to the
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* IA32 memory model, a simple store guarantees release semantics.
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@ -296,43 +334,39 @@ ATOMIC_STORE(long);
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#ifndef WANT_FUNCTIONS
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/* Read the current value and store a zero in the destination. */
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/* Read the current value and store a new value in the destination. */
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#ifdef __GNUCLIKE_ASM
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static __inline u_int
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atomic_readandclear_int(volatile u_int *p)
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atomic_swap_int(volatile u_int *p, u_int v)
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{
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u_int res;
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res = 0;
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__asm __volatile(
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" xchgl %1,%0 ; "
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"# atomic_readandclear_int"
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: "+r" (res), /* 0 */
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"# atomic_swap_int"
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: "+r" (v), /* 0 */
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"+m" (*p)); /* 1 */
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return (res);
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return (v);
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}
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static __inline u_long
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atomic_readandclear_long(volatile u_long *p)
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atomic_swap_long(volatile u_long *p, u_long v)
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{
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u_long res;
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res = 0;
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__asm __volatile(
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" xchgq %1,%0 ; "
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"# atomic_readandclear_long"
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: "+r" (res), /* 0 */
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"# atomic_swap_long"
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: "+r" (v), /* 0 */
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"+m" (*p)); /* 1 */
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return (res);
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return (v);
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}
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#else /* !__GNUCLIKE_ASM */
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u_int atomic_readandclear_int(volatile u_int *p);
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u_long atomic_readandclear_long(volatile u_long *p);
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u_int atomic_swap_int(volatile u_int *p, u_int v);
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u_long atomic_swap_long(volatile u_long *p, u_long v);
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#endif /* __GNUCLIKE_ASM */
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@ -376,6 +410,9 @@ u_long atomic_readandclear_long(volatile u_long *p);
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#define atomic_cmpset_acq_long atomic_cmpset_long
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#define atomic_cmpset_rel_long atomic_cmpset_long
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#define atomic_readandclear_int(p) atomic_swap_int(p, 0)
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#define atomic_readandclear_long(p) atomic_swap_long(p, 0)
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/* Operations on 8-bit bytes. */
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#define atomic_set_8 atomic_set_char
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#define atomic_set_acq_8 atomic_set_acq_char
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@ -426,8 +463,10 @@ u_long atomic_readandclear_long(volatile u_long *p);
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#define atomic_cmpset_32 atomic_cmpset_int
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#define atomic_cmpset_acq_32 atomic_cmpset_acq_int
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#define atomic_cmpset_rel_32 atomic_cmpset_rel_int
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#define atomic_swap_32 atomic_swap_int
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#define atomic_readandclear_32 atomic_readandclear_int
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#define atomic_fetchadd_32 atomic_fetchadd_int
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#define atomic_testandset_32 atomic_testandset_int
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/* Operations on 64-bit quad words. */
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#define atomic_set_64 atomic_set_long
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@ -447,7 +486,9 @@ u_long atomic_readandclear_long(volatile u_long *p);
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#define atomic_cmpset_64 atomic_cmpset_long
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#define atomic_cmpset_acq_64 atomic_cmpset_acq_long
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#define atomic_cmpset_rel_64 atomic_cmpset_rel_long
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#define atomic_swap_64 atomic_swap_long
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#define atomic_readandclear_64 atomic_readandclear_long
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#define atomic_testandset_64 atomic_testandset_long
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/* Operations on pointers. */
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#define atomic_set_ptr atomic_set_long
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@ -467,6 +508,7 @@ u_long atomic_readandclear_long(volatile u_long *p);
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#define atomic_cmpset_ptr atomic_cmpset_long
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#define atomic_cmpset_acq_ptr atomic_cmpset_acq_long
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#define atomic_cmpset_rel_ptr atomic_cmpset_rel_long
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#define atomic_swap_ptr atomic_swap_long
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#define atomic_readandclear_ptr atomic_readandclear_long
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#endif /* !WANT_FUNCTIONS */
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@ -54,12 +54,14 @@
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* atomic_clear_int(P, V) (*(u_int *)(P) &= ~(V))
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* atomic_add_int(P, V) (*(u_int *)(P) += (V))
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* atomic_subtract_int(P, V) (*(u_int *)(P) -= (V))
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* atomic_swap_int(P, V) (return (*(u_int *)(P)); *(u_int *)(P) = (V);)
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* atomic_readandclear_int(P) (return (*(u_int *)(P)); *(u_int *)(P) = 0;)
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*
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* atomic_set_long(P, V) (*(u_long *)(P) |= (V))
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* atomic_clear_long(P, V) (*(u_long *)(P) &= ~(V))
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* atomic_add_long(P, V) (*(u_long *)(P) += (V))
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* atomic_subtract_long(P, V) (*(u_long *)(P) -= (V))
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* atomic_swap_long(P, V) (return (*(u_long *)(P)); *(u_long *)(P) = (V);)
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* atomic_readandclear_long(P) (return (*(u_long *)(P)); *(u_long *)(P) = 0;)
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*/
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@ -78,6 +80,7 @@ void atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v)
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int atomic_cmpset_int(volatile u_int *dst, u_int expect, u_int src);
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u_int atomic_fetchadd_int(volatile u_int *p, u_int v);
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int atomic_testandset_int(volatile u_int *p, u_int v);
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#define ATOMIC_LOAD(TYPE, LOP) \
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u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p)
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@ -275,6 +278,23 @@ atomic_fetchadd_int(volatile u_int *p, u_int v)
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return (v);
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}
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static __inline int
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atomic_testandset_int(volatile u_int *p, u_int v)
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{
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u_char res;
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__asm __volatile(
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" " MPLOCKED " "
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" btsl %2,%1 ; "
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" setc %0 ; "
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"# atomic_testandset_int"
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: "=q" (res), /* 0 */
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"+m" (*p) /* 1 */
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: "Ir" (v & 0x1f) /* 2 */
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: "cc");
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return (res);
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}
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/*
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* We assume that a = b will do atomic loads and stores. Due to the
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* IA32 memory model, a simple store guarantees release semantics.
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@ -386,43 +406,40 @@ atomic_fetchadd_long(volatile u_long *p, u_long v)
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return (atomic_fetchadd_int((volatile u_int *)p, (u_int)v));
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}
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/* Read the current value and store a zero in the destination. */
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static __inline int
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atomic_testandset_long(volatile u_long *p, u_int v)
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{
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return (atomic_testandset_int((volatile u_int *)p, v));
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}
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/* Read the current value and store a new value in the destination. */
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#ifdef __GNUCLIKE_ASM
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static __inline u_int
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atomic_readandclear_int(volatile u_int *p)
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atomic_swap_int(volatile u_int *p, u_int v)
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{
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u_int res;
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res = 0;
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__asm __volatile(
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" xchgl %1,%0 ; "
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"# atomic_readandclear_int"
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: "+r" (res), /* 0 */
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"# atomic_swap_int"
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: "+r" (v), /* 0 */
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"+m" (*p)); /* 1 */
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return (res);
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return (v);
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}
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static __inline u_long
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atomic_readandclear_long(volatile u_long *p)
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atomic_swap_long(volatile u_long *p, u_long v)
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{
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u_long res;
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res = 0;
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__asm __volatile(
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" xchgl %1,%0 ; "
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"# atomic_readandclear_long"
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: "+r" (res), /* 0 */
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"+m" (*p)); /* 1 */
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return (res);
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return (atomic_swap_int((volatile u_int *)p, (u_int)v));
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}
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#else /* !__GNUCLIKE_ASM */
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u_int atomic_readandclear_int(volatile u_int *p);
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u_long atomic_readandclear_long(volatile u_long *p);
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u_int atomic_swap_int(volatile u_int *p, u_int v);
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u_long atomic_swap_long(volatile u_long *p, u_long v);
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#endif /* __GNUCLIKE_ASM */
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@ -466,6 +483,9 @@ u_long atomic_readandclear_long(volatile u_long *p);
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#define atomic_cmpset_acq_long atomic_cmpset_long
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#define atomic_cmpset_rel_long atomic_cmpset_long
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#define atomic_readandclear_int(p) atomic_swap_int(p, 0)
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#define atomic_readandclear_long(p) atomic_swap_long(p, 0)
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/* Operations on 8-bit bytes. */
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#define atomic_set_8 atomic_set_char
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#define atomic_set_acq_8 atomic_set_acq_char
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@ -516,8 +536,10 @@ u_long atomic_readandclear_long(volatile u_long *p);
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#define atomic_cmpset_32 atomic_cmpset_int
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#define atomic_cmpset_acq_32 atomic_cmpset_acq_int
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#define atomic_cmpset_rel_32 atomic_cmpset_rel_int
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#define atomic_swap_32 atomic_swap_int
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#define atomic_readandclear_32 atomic_readandclear_int
|
||||
#define atomic_fetchadd_32 atomic_fetchadd_int
|
||||
#define atomic_testandset_32 atomic_testandset_int
|
||||
|
||||
/* Operations on pointers. */
|
||||
#define atomic_set_ptr(p, v) \
|
||||
@ -556,6 +578,8 @@ u_long atomic_readandclear_long(volatile u_long *p);
|
||||
#define atomic_cmpset_rel_ptr(dst, old, new) \
|
||||
atomic_cmpset_rel_int((volatile u_int *)(dst), (u_int)(old), \
|
||||
(u_int)(new))
|
||||
#define atomic_swap_ptr(p, v) \
|
||||
atomic_swap_int((volatile u_int *)(p), (u_int)(v))
|
||||
#define atomic_readandclear_ptr(p) \
|
||||
atomic_readandclear_int((volatile u_int *)(p))
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user