Date: Tue, 30 Jul 2013 15:56:36 -0400 From: Jung-uk Kim <jkim@FreeBSD.org> To: freebsd-arch@FreeBSD.org Cc: kib@FreeBSD.org, dumbbell@FreeBSD.org Subject: [PATCH] Atomic swap and test-and-set Message-ID: <51F81A74.4030009@FreeBSD.org>
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This is a multi-part message in MIME format. --------------050506090501030302020606 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The attached patch implements atomic_swap_<type>() and atomic_testandset_<type>() for x86. <type> is int or long ATM. The semantics of each operation (in atomic(9) style): atomic_swap(p, v) r = *p; *p = v; return (r); atomic_testandset(p, s) v = (<type>)1 << s % (sizeof(<type>) * NBBY); r = (*p & v) != 0; *p |= v; return (r); Note atomic_readandclear_<type>() is now obsolete and implemented as a macro around atomic_swap_<type>() where the new value v is 0. Please let me know if you have any objection. Thanks! Jung-uk Kim * Note 1: This patch is also available from here. http://people.freebsd.org/~jkim/atomic.diff * Note 2: These atomic ops are useful for porting Linux drivers and it may simplify diffs, e.g., drm2 for AMD GPUs project. Currently, I am using the following wrapper: http://people.freebsd.org/~jkim/drm_atomic.h A full patch against kms-radeon tree is here: http://people.freebsd.org/~jkim/drm_atomic.diff -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (FreeBSD) iQEcBAEBAgAGBQJR+Bp0AAoJECXpabHZMqHOpIsIAMqEjNehGRe7q7B7CPC2cqdY aEWiRlKXLa0K3Vi2f9asYFlbhIm+PstV8Juhw2ijT/P3i55xoQTc4DqP6H4ISUgK pKM8TLAFJWlItf3o8HV/q7Tns/iaqb8cnB0D2jLUtheeM8UTXEim+XOSWILL+csR zuXGDSDGC0vTxip00ocPUdtdG/Y5Sg/Eq+5CZYp58DSoEBDfuKhGJc3xrC6QrMGx zwBkmAp5escfFkyE1WLI99tJevrQZpqJViD+66dDcLW56w4Aqpqib69sMMEs/meJ KrwKRwt9+kgvwEFiDGXzDsjVfcTky9Cb8zn3jbBrGxtNxd4aHgCNY1xeG98kHaM= =6LmO -----END PGP SIGNATURE----- --------------050506090501030302020606 Content-Type: text/x-patch; name="atomic.diff" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="atomic.diff" Index: sys/amd64/include/atomic.h =================================================================== --- sys/amd64/include/atomic.h (revision 253812) +++ sys/amd64/include/atomic.h (working copy) @@ -54,6 +54,7 @@ * atomic_clear_int(P, V) (*(u_int *)(P) &= ~(V)) * atomic_add_int(P, V) (*(u_int *)(P) += (V)) * atomic_subtract_int(P, V) (*(u_int *)(P) -= (V)) + * atomic_swap_int(P, V) (return (*(u_int *)(P)); *(u_int *)(P) = (V);) * atomic_readandclear_int(P) (return (*(u_int *)(P)); *(u_int *)(P) = 0;) * * atomic_set_long(P, V) (*(u_long *)(P) |= (V)) @@ -60,6 +61,7 @@ * atomic_clear_long(P, V) (*(u_long *)(P) &= ~(V)) * atomic_add_long(P, V) (*(u_long *)(P) += (V)) * atomic_subtract_long(P, V) (*(u_long *)(P) -= (V)) + * atomic_swap_long(P, V) (return (*(u_long *)(P)); *(u_long *)(P) = (V);) * atomic_readandclear_long(P) (return (*(u_long *)(P)); *(u_long *)(P) = 0;) */ @@ -80,6 +82,8 @@ int atomic_cmpset_int(volatile u_int *dst, u_int e int atomic_cmpset_long(volatile u_long *dst, u_long expect, u_long src); u_int atomic_fetchadd_int(volatile u_int *p, u_int v); u_long atomic_fetchadd_long(volatile u_long *p, u_long v); +int atomic_testandset_int(volatile u_int *p, int v); +int atomic_testandset_long(volatile u_long *p, int v); #define ATOMIC_LOAD(TYPE, LOP) \ u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p) @@ -211,6 +215,44 @@ atomic_fetchadd_long(volatile u_long *p, u_long v) return (v); } +static __inline int +atomic_testandset_int(volatile u_int *p, int v) +{ + u_char res; + + __asm __volatile( + " " MPLOCKED " " + " btsl %2, %1 ; " + " setc %0 ; " + "# atomic_testandset_int" + : "=r" (res), /* 0 */ + "=m" (*p) /* 1 */ + : "r" (v), /* 2 */ + "m" (*p) + : "cc"); + + return (res); +} + +static __inline int +atomic_testandset_long(volatile u_long *p, int v) +{ + u_char res; + + __asm __volatile( + " " MPLOCKED " " + " btsq %2, %1 ; " + " setc %0 ; " + "# atomic_testandset_long" + : "=r" (res), /* 0 */ + "=m" (*p) /* 1 */ + : "r" ((u_long)v), /* 2 */ + "m" (*p) + : "cc"); + + return (res); +} + /* * We assume that a = b will do atomic loads and stores. Due to the * IA32 memory model, a simple store guarantees release semantics. @@ -303,45 +345,41 @@ ATOMIC_STORE(long); #ifndef WANT_FUNCTIONS -/* Read the current value and store a zero in the destination. */ +/* Read the current value and store a new value in the destination. */ #ifdef __GNUCLIKE_ASM static __inline u_int -atomic_readandclear_int(volatile u_int *addr) +atomic_swap_int(volatile u_int *p, u_int v) { - u_int res; - res = 0; __asm __volatile( - " xchgl %1,%0 ; " - "# atomic_readandclear_int" - : "+r" (res), /* 0 */ - "=m" (*addr) /* 1 */ - : "m" (*addr)); + " xchgl %1, %0 ; " + "# atomic_swap_int" + : "+r" (v), /* 0 */ + "=m" (*p) /* 1 */ + : "m" (*p)); - return (res); + return (v); } static __inline u_long -atomic_readandclear_long(volatile u_long *addr) +atomic_swap_long(volatile u_long *p, u_long v) { - u_long res; - res = 0; __asm __volatile( - " xchgq %1,%0 ; " - "# atomic_readandclear_long" - : "+r" (res), /* 0 */ - "=m" (*addr) /* 1 */ - : "m" (*addr)); + " xchgq %1, %0 ; " + "# atomic_swap_long" + : "+r" (v), /* 0 */ + "=m" (*p) /* 1 */ + : "m" (*p)); - return (res); + return (v); } #else /* !__GNUCLIKE_ASM */ -u_int atomic_readandclear_int(volatile u_int *addr); -u_long atomic_readandclear_long(volatile u_long *addr); +u_int atomic_swap_int(volatile u_int *, u_int); +u_long atomic_swap_long(volatile u_long *, u_long); #endif /* __GNUCLIKE_ASM */ @@ -385,6 +423,9 @@ static __inline u_long #define atomic_cmpset_acq_long atomic_cmpset_long #define atomic_cmpset_rel_long atomic_cmpset_long +#define atomic_readandclear_int(p) atomic_swap_int(p, 0) +#define atomic_readandclear_long(p) atomic_swap_long(p, 0) + /* Operations on 8-bit bytes. */ #define atomic_set_8 atomic_set_char #define atomic_set_acq_8 atomic_set_acq_char @@ -435,8 +476,10 @@ static __inline u_long #define atomic_cmpset_32 atomic_cmpset_int #define atomic_cmpset_acq_32 atomic_cmpset_acq_int #define atomic_cmpset_rel_32 atomic_cmpset_rel_int +#define atomic_swap_32 atomic_swap_int #define atomic_readandclear_32 atomic_readandclear_int #define atomic_fetchadd_32 atomic_fetchadd_int +#define atomic_testandset_32 atomic_testandset_int /* Operations on 64-bit quad words. */ #define atomic_set_64 atomic_set_long @@ -456,7 +499,9 @@ static __inline u_long #define atomic_cmpset_64 atomic_cmpset_long #define atomic_cmpset_acq_64 atomic_cmpset_acq_long #define atomic_cmpset_rel_64 atomic_cmpset_rel_long +#define atomic_swap_64 atomic_swap_long #define atomic_readandclear_64 atomic_readandclear_long +#define atomic_testandset_64 atomic_testandset_long /* Operations on pointers. */ #define atomic_set_ptr atomic_set_long @@ -476,6 +521,7 @@ static __inline u_long #define atomic_cmpset_ptr atomic_cmpset_long #define atomic_cmpset_acq_ptr atomic_cmpset_acq_long #define atomic_cmpset_rel_ptr atomic_cmpset_rel_long +#define atomic_swap_ptr atomic_swap_long #define atomic_readandclear_ptr atomic_readandclear_long #endif /* !WANT_FUNCTIONS */ Index: sys/i386/include/atomic.h =================================================================== --- sys/i386/include/atomic.h (revision 253812) +++ sys/i386/include/atomic.h (working copy) @@ -54,6 +54,7 @@ * atomic_clear_int(P, V) (*(u_int *)(P) &= ~(V)) * atomic_add_int(P, V) (*(u_int *)(P) += (V)) * atomic_subtract_int(P, V) (*(u_int *)(P) -= (V)) + * atomic_swap_int(P, V) (return (*(u_int *)(P)); *(u_int *)(P) = (V);) * atomic_readandclear_int(P) (return (*(u_int *)(P)); *(u_int *)(P) = 0;) * * atomic_set_long(P, V) (*(u_long *)(P) |= (V)) @@ -60,6 +61,7 @@ * atomic_clear_long(P, V) (*(u_long *)(P) &= ~(V)) * atomic_add_long(P, V) (*(u_long *)(P) += (V)) * atomic_subtract_long(P, V) (*(u_long *)(P) -= (V)) + * atomic_swap_long(P, V) (return (*(u_long *)(P)); *(u_long *)(P) = (V);) * atomic_readandclear_long(P) (return (*(u_long *)(P)); *(u_long *)(P) = 0;) */ @@ -78,6 +80,7 @@ void atomic_##NAME##_barr_##TYPE(volatile u_##TYPE int atomic_cmpset_int(volatile u_int *dst, u_int expect, u_int src); u_int atomic_fetchadd_int(volatile u_int *p, u_int v); +int atomic_testandset_int(volatile u_int *p, int v); #define ATOMIC_LOAD(TYPE, LOP) \ u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p) @@ -281,6 +284,25 @@ atomic_fetchadd_int(volatile u_int *p, u_int v) return (v); } +static __inline int +atomic_testandset_int(volatile u_int *p, int v) +{ + u_char res; + + __asm __volatile( + " " MPLOCKED " " + " btsl %2, %1 ; " + " setc %0 ; " + "# atomic_testandset_int" + : "=r" (res), /* 0 */ + "=m" (*p) /* 1 */ + : "r" (v), /* 2 */ + "m" (*p) + : "cc"); + + return (res); +} + /* * We assume that a = b will do atomic loads and stores. Due to the * IA32 memory model, a simple store guarantees release semantics. @@ -393,45 +415,41 @@ atomic_fetchadd_long(volatile u_long *p, u_long v) return (atomic_fetchadd_int((volatile u_int *)p, (u_int)v)); } -/* Read the current value and store a zero in the destination. */ +static __inline int +atomic_testandset_long(volatile u_long *p, int v) +{ + + return (atomic_testandset_int((volatile u_int *)p, v)); +} + +/* Read the current value and store a new value in the destination. */ #ifdef __GNUCLIKE_ASM static __inline u_int -atomic_readandclear_int(volatile u_int *addr) +atomic_swap_int(volatile u_int *p, u_int v) { - u_int res; - res = 0; __asm __volatile( - " xchgl %1,%0 ; " - "# atomic_readandclear_int" - : "+r" (res), /* 0 */ - "=m" (*addr) /* 1 */ - : "m" (*addr)); + " xchgl %1, %0 ; " + "# atomic_swap_int" + : "+r" (v), /* 0 */ + "=m" (*p) /* 1 */ + : "m" (*p)); - return (res); + return (v); } static __inline u_long -atomic_readandclear_long(volatile u_long *addr) +atomic_swap_long(volatile u_long *p, u_long v) { - u_long res; - res = 0; - __asm __volatile( - " xchgl %1,%0 ; " - "# atomic_readandclear_long" - : "+r" (res), /* 0 */ - "=m" (*addr) /* 1 */ - : "m" (*addr)); - - return (res); + return (atomic_swap_int((volatile u_int *)p, (u_int)v)); } #else /* !__GNUCLIKE_ASM */ -u_int atomic_readandclear_int(volatile u_int *addr); -u_long atomic_readandclear_long(volatile u_long *addr); +u_int atomic_swap_int(volatile u_int *, u_int); +u_long atomic_swap_long(volatile u_long *, u_long); #endif /* __GNUCLIKE_ASM */ @@ -475,6 +493,9 @@ static __inline u_long #define atomic_cmpset_acq_long atomic_cmpset_long #define atomic_cmpset_rel_long atomic_cmpset_long +#define atomic_readandclear_int(p) atomic_swap_int(p, 0) +#define atomic_readandclear_long(p) atomic_swap_long(p, 0) + /* Operations on 8-bit bytes. */ #define atomic_set_8 atomic_set_char #define atomic_set_acq_8 atomic_set_acq_char @@ -525,8 +546,10 @@ static __inline u_long #define atomic_cmpset_32 atomic_cmpset_int #define atomic_cmpset_acq_32 atomic_cmpset_acq_int #define atomic_cmpset_rel_32 atomic_cmpset_rel_int +#define atomic_swap_32 atomic_swap_int #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) \ @@ -565,6 +588,8 @@ static __inline u_long #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)) --------------050506090501030302020606--
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