/*- * Copyright (c) 1998 Doug Rabson * 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. * * $FreeBSD$ */ #ifndef _MACHINE_ATOMIC_H_ #define _MACHINE_ATOMIC_H_ #ifndef _SYS_CDEFS_H_ #error this file needs sys/cdefs.h as a prerequisite #endif /* * To express interprocessor (as opposed to processor and device) memory * ordering constraints, use the atomic_*() functions with acquire and release * semantics rather than the *mb() functions. An architecture's memory * ordering (or memory consistency) model governs the order in which a * program's accesses to different locations may be performed by an * implementation of that architecture. In general, for memory regions * defined as writeback cacheable, the memory ordering implemented by amd64 * processors preserves the program ordering of a load followed by a load, a * load followed by a store, and a store followed by a store. Only a store * followed by a load to a different memory location may be reordered. * Therefore, except for special cases, like non-temporal memory accesses or * memory regions defined as write combining, the memory ordering effects * provided by the sfence instruction in the wmb() function and the lfence * instruction in the rmb() function are redundant. In contrast, the * atomic_*() functions with acquire and release semantics do not perform * redundant instructions for ordinary cases of interprocessor memory * ordering on any architecture. */ #define mb() __asm __volatile("mfence;" : : : "memory") #define wmb() __asm __volatile("sfence;" : : : "memory") #define rmb() __asm __volatile("lfence;" : : : "memory") /* * Various simple operations on memory, each of which is atomic in the * presence of interrupts and multiple processors. * * atomic_set_char(P, V) (*(u_char *)(P) |= (V)) * atomic_clear_char(P, V) (*(u_char *)(P) &= ~(V)) * atomic_add_char(P, V) (*(u_char *)(P) += (V)) * atomic_subtract_char(P, V) (*(u_char *)(P) -= (V)) * * atomic_set_short(P, V) (*(u_short *)(P) |= (V)) * atomic_clear_short(P, V) (*(u_short *)(P) &= ~(V)) * atomic_add_short(P, V) (*(u_short *)(P) += (V)) * atomic_subtract_short(P, V) (*(u_short *)(P) -= (V)) * * atomic_set_int(P, V) (*(u_int *)(P) |= (V)) * 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)) * 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;) */ /* * The above functions are expanded inline in the statically-linked * kernel. Lock prefixes are generated if an SMP kernel is being * built. * * Kernel modules call real functions which are built into the kernel. * This allows kernel modules to be portable between UP and SMP systems. */ #if defined(KLD_MODULE) || !defined(__GNUCLIKE_ASM) #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v); \ void atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v) int atomic_cmpset_int(volatile u_int *dst, u_int expect, u_int src); 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, u_int v); int atomic_testandset_long(volatile u_long *p, u_int v); int atomic_testandclear_int(volatile u_int *p, u_int v); int atomic_testandclear_long(volatile u_long *p, u_int v); void atomic_thread_fence_acq(void); void atomic_thread_fence_acq_rel(void); void atomic_thread_fence_rel(void); void atomic_thread_fence_seq_cst(void); #define ATOMIC_LOAD(TYPE) \ u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p) #define ATOMIC_STORE(TYPE) \ void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) #else /* !KLD_MODULE && __GNUCLIKE_ASM */ /* * For userland, always use lock prefixes so that the binaries will run * on both SMP and !SMP systems. */ #if defined(SMP) || !defined(_KERNEL) #define MPLOCKED "lock ; " #else #define MPLOCKED #endif /* * The assembly is volatilized to avoid code chunk removal by the compiler. * GCC aggressively reorders operations and memory clobbering is necessary * in order to avoid that for memory barriers. */ #define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \ static __inline void \ atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ { \ __asm __volatile(MPLOCKED OP \ : "+m" (*p) \ : CONS (V) \ : "cc"); \ } \ \ static __inline void \ atomic_##NAME##_barr_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ { \ __asm __volatile(MPLOCKED OP \ : "+m" (*p) \ : CONS (V) \ : "memory", "cc"); \ } \ struct __hack /* * Atomic compare and set, used by the mutex functions * * if (*dst == expect) *dst = src (all 32 bit words) * * Returns 0 on failure, non-zero on success */ static __inline int atomic_cmpset_int(volatile u_int *dst, u_int expect, u_int src) { u_char res; __asm __volatile( " " MPLOCKED " " " cmpxchgl %3,%1 ; " " sete %0 ; " "# atomic_cmpset_int" : "=q" (res), /* 0 */ "+m" (*dst), /* 1 */ "+a" (expect) /* 2 */ : "r" (src) /* 3 */ : "memory", "cc"); return (res); } static __inline int atomic_cmpset_long(volatile u_long *dst, u_long expect, u_long src) { u_char res; __asm __volatile( " " MPLOCKED " " " cmpxchgq %3,%1 ; " " sete %0 ; " "# atomic_cmpset_long" : "=q" (res), /* 0 */ "+m" (*dst), /* 1 */ "+a" (expect) /* 2 */ : "r" (src) /* 3 */ : "memory", "cc"); return (res); } /* * 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 u_int *p, u_int v) { __asm __volatile( " " MPLOCKED " " " xaddl %0,%1 ; " "# atomic_fetchadd_int" : "+r" (v), /* 0 */ "+m" (*p) /* 1 */ : : "cc"); return (v); } /* * Atomically add the value of v to the long integer pointed to by p and return * the previous value of *p. */ static __inline u_long atomic_fetchadd_long(volatile u_long *p, u_long v) { __asm __volatile( " " MPLOCKED " " " xaddq %0,%1 ; " "# atomic_fetchadd_long" : "+r" (v), /* 0 */ "+m" (*p) /* 1 */ : : "cc"); return (v); } static __inline int atomic_testandset_int(volatile u_int *p, u_int v) { u_char res; __asm __volatile( " " MPLOCKED " " " btsl %2,%1 ; " " setc %0 ; " "# atomic_testandset_int" : "=q" (res), /* 0 */ "+m" (*p) /* 1 */ : "Ir" (v & 0x1f) /* 2 */ : "cc"); return (res); } static __inline int atomic_testandset_long(volatile u_long *p, u_int v) { u_char res; __asm __volatile( " " MPLOCKED " " " btsq %2,%1 ; " " setc %0 ; " "# atomic_testandset_long" : "=q" (res), /* 0 */ "+m" (*p) /* 1 */ : "Jr" ((u_long)(v & 0x3f)) /* 2 */ : "cc"); return (res); } static __inline int atomic_testandclear_int(volatile u_int *p, u_int v) { u_char res; __asm __volatile( " " MPLOCKED " " " btrl %2,%1 ; " " setc %0 ; " "# atomic_testandclear_int" : "=q" (res), /* 0 */ "+m" (*p) /* 1 */ : "Ir" (v & 0x1f) /* 2 */ : "cc"); return (res); } static __inline int atomic_testandclear_long(volatile u_long *p, u_int v) { u_char res; __asm __volatile( " " MPLOCKED " " " btrq %2,%1 ; " " setc %0 ; " "# atomic_testandclear_long" : "=q" (res), /* 0 */ "+m" (*p) /* 1 */ : "Jr" ((u_long)(v & 0x3f)) /* 2 */ : "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. * * However, a load may pass a store if they are performed on distinct * addresses, so we need a Store/Load barrier for sequentially * consistent fences in SMP kernels. We use "lock addl $0,mem" for a * Store/Load barrier, as recommended by the AMD Software Optimization * Guide, and not mfence. To avoid false data dependencies, we use a * special address for "mem". In the kernel, we use a private per-cpu * cache line. In user space, we use a word in the stack's red zone * (-8(%rsp)). * * For UP kernels, however, the memory of the single processor is * always consistent, so we only need to stop the compiler from * reordering accesses in a way that violates the semantics of acquire * and release. */ #if defined(_KERNEL) /* * OFFSETOF_MONITORBUF == __pcpu_offset(pc_monitorbuf). * * The open-coded number is used instead of the symbolic expression to * avoid a dependency on sys/pcpu.h in machine/atomic.h consumers. * An assertion in amd64/vm_machdep.c ensures that the value is correct. */ #define OFFSETOF_MONITORBUF 0x180 #if defined(SMP) static __inline void __storeload_barrier(void) { __asm __volatile("lock; addl $0,%%gs:%0" : "+m" (*(u_int *)OFFSETOF_MONITORBUF) : : "memory", "cc"); } #else /* _KERNEL && UP */ static __inline void __storeload_barrier(void) { __compiler_membar(); } #endif /* SMP */ #else /* !_KERNEL */ static __inline void __storeload_barrier(void) { __asm __volatile("lock; addl $0,-8(%%rsp)" : : : "memory", "cc"); } #endif /* _KERNEL*/ #define ATOMIC_LOAD(TYPE) \ static __inline u_##TYPE \ atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ { \ u_##TYPE res; \ \ res = *p; \ __compiler_membar(); \ return (res); \ } \ struct __hack #define ATOMIC_STORE(TYPE) \ static __inline void \ atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v) \ { \ \ __compiler_membar(); \ *p = v; \ } \ struct __hack static __inline void atomic_thread_fence_acq(void) { __compiler_membar(); } static __inline void atomic_thread_fence_rel(void) { __compiler_membar(); } static __inline void atomic_thread_fence_acq_rel(void) { __compiler_membar(); } static __inline void atomic_thread_fence_seq_cst(void) { __storeload_barrier(); } #endif /* KLD_MODULE || !__GNUCLIKE_ASM */ ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v); ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v); ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v); ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v); ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v); ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v); ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v); ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v); ATOMIC_ASM(set, int, "orl %1,%0", "ir", v); ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v); ATOMIC_ASM(add, int, "addl %1,%0", "ir", v); ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v); ATOMIC_ASM(set, long, "orq %1,%0", "ir", v); ATOMIC_ASM(clear, long, "andq %1,%0", "ir", ~v); ATOMIC_ASM(add, long, "addq %1,%0", "ir", v); ATOMIC_ASM(subtract, long, "subq %1,%0", "ir", v); #define ATOMIC_LOADSTORE(TYPE) \ ATOMIC_LOAD(TYPE); \ ATOMIC_STORE(TYPE) ATOMIC_LOADSTORE(char); ATOMIC_LOADSTORE(short); ATOMIC_LOADSTORE(int); ATOMIC_LOADSTORE(long); #undef ATOMIC_ASM #undef ATOMIC_LOAD #undef ATOMIC_STORE #undef ATOMIC_LOADSTORE #ifndef WANT_FUNCTIONS /* Read the current value and store a new value in the destination. */ #ifdef __GNUCLIKE_ASM static __inline u_int atomic_swap_int(volatile u_int *p, u_int v) { __asm __volatile( " xchgl %1,%0 ; " "# atomic_swap_int" : "+r" (v), /* 0 */ "+m" (*p)); /* 1 */ return (v); } static __inline u_long atomic_swap_long(volatile u_long *p, u_long v) { __asm __volatile( " xchgq %1,%0 ; " "# atomic_swap_long" : "+r" (v), /* 0 */ "+m" (*p)); /* 1 */ return (v); } #else /* !__GNUCLIKE_ASM */ u_int atomic_swap_int(volatile u_int *p, u_int v); u_long atomic_swap_long(volatile u_long *p, u_long v); #endif /* __GNUCLIKE_ASM */ #define atomic_set_acq_char atomic_set_barr_char #define atomic_set_rel_char atomic_set_barr_char #define atomic_clear_acq_char atomic_clear_barr_char #define atomic_clear_rel_char atomic_clear_barr_char #define atomic_add_acq_char atomic_add_barr_char #define atomic_add_rel_char atomic_add_barr_char #define atomic_subtract_acq_char atomic_subtract_barr_char #define atomic_subtract_rel_char atomic_subtract_barr_char #define atomic_set_acq_short atomic_set_barr_short #define atomic_set_rel_short atomic_set_barr_short #define atomic_clear_acq_short atomic_clear_barr_short #define atomic_clear_rel_short atomic_clear_barr_short #define atomic_add_acq_short atomic_add_barr_short #define atomic_add_rel_short atomic_add_barr_short #define atomic_subtract_acq_short atomic_subtract_barr_short #define atomic_subtract_rel_short atomic_subtract_barr_short #define atomic_set_acq_int atomic_set_barr_int #define atomic_set_rel_int atomic_set_barr_int #define atomic_clear_acq_int atomic_clear_barr_int #define atomic_clear_rel_int atomic_clear_barr_int #define atomic_add_acq_int atomic_add_barr_int #define atomic_add_rel_int atomic_add_barr_int #define atomic_subtract_acq_int atomic_subtract_barr_int #define atomic_subtract_rel_int atomic_subtract_barr_int #define atomic_cmpset_acq_int atomic_cmpset_int #define atomic_cmpset_rel_int atomic_cmpset_int #define atomic_set_acq_long atomic_set_barr_long #define atomic_set_rel_long atomic_set_barr_long #define atomic_clear_acq_long atomic_clear_barr_long #define atomic_clear_rel_long atomic_clear_barr_long #define atomic_add_acq_long atomic_add_barr_long #define atomic_add_rel_long atomic_add_barr_long #define atomic_subtract_acq_long atomic_subtract_barr_long #define atomic_subtract_rel_long atomic_subtract_barr_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 #define atomic_set_rel_8 atomic_set_rel_char #define atomic_clear_8 atomic_clear_char #define atomic_clear_acq_8 atomic_clear_acq_char #define atomic_clear_rel_8 atomic_clear_rel_char #define atomic_add_8 atomic_add_char #define atomic_add_acq_8 atomic_add_acq_char #define atomic_add_rel_8 atomic_add_rel_char #define atomic_subtract_8 atomic_subtract_char #define atomic_subtract_acq_8 atomic_subtract_acq_char #define atomic_subtract_rel_8 atomic_subtract_rel_char #define atomic_load_acq_8 atomic_load_acq_char #define atomic_store_rel_8 atomic_store_rel_char /* Operations on 16-bit words. */ #define atomic_set_16 atomic_set_short #define atomic_set_acq_16 atomic_set_acq_short #define atomic_set_rel_16 atomic_set_rel_short #define atomic_clear_16 atomic_clear_short #define atomic_clear_acq_16 atomic_clear_acq_short #define atomic_clear_rel_16 atomic_clear_rel_short #define atomic_add_16 atomic_add_short #define atomic_add_acq_16 atomic_add_acq_short #define atomic_add_rel_16 atomic_add_rel_short #define atomic_subtract_16 atomic_subtract_short #define atomic_subtract_acq_16 atomic_subtract_acq_short #define atomic_subtract_rel_16 atomic_subtract_rel_short #define atomic_load_acq_16 atomic_load_acq_short #define atomic_store_rel_16 atomic_store_rel_short /* Operations on 32-bit double words. */ #define atomic_set_32 atomic_set_int #define atomic_set_acq_32 atomic_set_acq_int #define atomic_set_rel_32 atomic_set_rel_int #define atomic_clear_32 atomic_clear_int #define atomic_clear_acq_32 atomic_clear_acq_int #define atomic_clear_rel_32 atomic_clear_rel_int #define atomic_add_32 atomic_add_int #define atomic_add_acq_32 atomic_add_acq_int #define atomic_add_rel_32 atomic_add_rel_int #define atomic_subtract_32 atomic_subtract_int #define atomic_subtract_acq_32 atomic_subtract_acq_int #define atomic_subtract_rel_32 atomic_subtract_rel_int #define atomic_load_acq_32 atomic_load_acq_int #define atomic_store_rel_32 atomic_store_rel_int #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 #define atomic_testandclear_32 atomic_testandclear_int /* Operations on 64-bit quad words. */ #define atomic_set_64 atomic_set_long #define atomic_set_acq_64 atomic_set_acq_long #define atomic_set_rel_64 atomic_set_rel_long #define atomic_clear_64 atomic_clear_long #define atomic_clear_acq_64 atomic_clear_acq_long #define atomic_clear_rel_64 atomic_clear_rel_long #define atomic_add_64 atomic_add_long #define atomic_add_acq_64 atomic_add_acq_long #define atomic_add_rel_64 atomic_add_rel_long #define atomic_subtract_64 atomic_subtract_long #define atomic_subtract_acq_64 atomic_subtract_acq_long #define atomic_subtract_rel_64 atomic_subtract_rel_long #define atomic_load_acq_64 atomic_load_acq_long #define atomic_store_rel_64 atomic_store_rel_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_fetchadd_64 atomic_fetchadd_long #define atomic_testandset_64 atomic_testandset_long #define atomic_testandclear_64 atomic_testandclear_long /* Operations on pointers. */ #define atomic_set_ptr atomic_set_long #define atomic_set_acq_ptr atomic_set_acq_long #define atomic_set_rel_ptr atomic_set_rel_long #define atomic_clear_ptr atomic_clear_long #define atomic_clear_acq_ptr atomic_clear_acq_long #define atomic_clear_rel_ptr atomic_clear_rel_long #define atomic_add_ptr atomic_add_long #define atomic_add_acq_ptr atomic_add_acq_long #define atomic_add_rel_ptr atomic_add_rel_long #define atomic_subtract_ptr atomic_subtract_long #define atomic_subtract_acq_ptr atomic_subtract_acq_long #define atomic_subtract_rel_ptr atomic_subtract_rel_long #define atomic_load_acq_ptr atomic_load_acq_long #define atomic_store_rel_ptr atomic_store_rel_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 */ #endif /* !_MACHINE_ATOMIC_H_ */