1 // SPDX-FileCopyrightText: 2010 Paolo Bonzini <pbonzini@redhat.com>
3 // SPDX-License-Identifier: LGPL-2.1-or-later
5 #ifndef _URCU_ARCH_GENERIC_H
6 #define _URCU_ARCH_GENERIC_H
9 * arch_generic.h: common definitions for multiple architectures.
12 #include <urcu/compiler.h>
13 #include <urcu/config.h>
14 #include <urcu/syscall-compat.h>
20 #ifndef CAA_CACHE_LINE_SIZE
21 #define CAA_CACHE_LINE_SIZE 64
24 #if !defined(cmm_mc) && !defined(cmm_rmc) && !defined(cmm_wmc)
25 #define CONFIG_HAVE_MEM_COHERENCY
27 * Architectures with cache coherency must _not_ define cmm_mc/cmm_rmc/cmm_wmc.
29 * For them, cmm_mc/cmm_rmc/cmm_wmc are implemented with a simple
30 * compiler barrier; in addition, we provide defaults for cmm_mb (using
31 * GCC builtins) as well as cmm_rmb and cmm_wmb (defaulting to cmm_mb).
34 #ifdef CONFIG_RCU_USE_ATOMIC_BUILTINS
37 # define cmm_smp_mb() __atomic_thread_fence(__ATOMIC_SEQ_CST)
40 #endif /* CONFIG_RCU_USE_ATOMIC_BUILTINS */
44 * cmm_mb() expands to __sync_synchronize() instead of __atomic_thread_fence
45 * with SEQ_CST because the former "issues a full memory barrier" while the
46 * latter "acts as a synchronization fence between threads" which is too weak
47 * for what we want, for example with I/O devices.
49 * Even though sync_synchronize seems to be an alias for a sequential consistent
50 * atomic thread fence on every architecture on GCC and Clang, this assumption
51 * might be untrue in future. Therefore, the definitions above are used to
52 * ensure correct behavior in the future.
54 * The above defintions are quoted from the GCC manual.
57 #define cmm_mb() __sync_synchronize()
61 #define cmm_rmb() cmm_mb()
65 #define cmm_wmb() cmm_mb()
68 #define cmm_mc() cmm_barrier()
69 #define cmm_rmc() cmm_barrier()
70 #define cmm_wmc() cmm_barrier()
73 * Architectures without cache coherency need something like the following:
75 * #define cmm_mc() arch_cache_flush()
76 * #define cmm_rmc() arch_cache_flush_read()
77 * #define cmm_wmc() arch_cache_flush_write()
79 * Of these, only cmm_mc is mandatory. cmm_rmc and cmm_wmc default to
80 * cmm_mc. cmm_mb/cmm_rmb/cmm_wmb use these definitions by default:
82 * #define cmm_mb() cmm_mc()
83 * #define cmm_rmb() cmm_rmc()
84 * #define cmm_wmb() cmm_wmc()
88 #define cmm_mb() cmm_mc()
92 #define cmm_rmb() cmm_rmc()
96 #define cmm_wmb() cmm_wmc()
100 #define cmm_rmc() cmm_mc()
104 #define cmm_wmc() cmm_mc()
108 /* Nop everywhere except on alpha. */
109 #ifndef cmm_read_barrier_depends
110 #define cmm_read_barrier_depends()
113 #ifdef CONFIG_RCU_SMP
115 #define cmm_smp_mb() cmm_mb()
118 #define cmm_smp_rmb() cmm_rmb()
121 #define cmm_smp_wmb() cmm_wmb()
124 #define cmm_smp_mc() cmm_mc()
127 #define cmm_smp_rmc() cmm_rmc()
130 #define cmm_smp_wmc() cmm_wmc()
132 #ifndef cmm_smp_read_barrier_depends
133 #define cmm_smp_read_barrier_depends() cmm_read_barrier_depends()
137 #define cmm_smp_mb() cmm_barrier()
140 #define cmm_smp_rmb() cmm_barrier()
143 #define cmm_smp_wmb() cmm_barrier()
146 #define cmm_smp_mc() cmm_barrier()
149 #define cmm_smp_rmc() cmm_barrier()
152 #define cmm_smp_wmc() cmm_barrier()
154 #ifndef cmm_smp_read_barrier_depends
155 #define cmm_smp_read_barrier_depends()
159 #ifndef caa_cpu_relax
160 #define caa_cpu_relax() cmm_barrier()
163 #ifndef HAS_CAA_GET_CYCLES
164 #define HAS_CAA_GET_CYCLES
166 #if defined(__APPLE__)
168 #include <mach/mach.h>
169 #include <mach/clock.h>
170 #include <mach/mach_time.h>
174 typedef uint64_t caa_cycles_t
;
176 static inline caa_cycles_t
caa_get_cycles (void)
178 mach_timespec_t ts
= { 0, 0 };
179 static clock_serv_t clock_service
;
181 if (caa_unlikely(!clock_service
)) {
182 if (host_get_clock_service(mach_host_self(),
183 SYSTEM_CLOCK
, &clock_service
))
186 if (caa_unlikely(clock_get_time(clock_service
, &ts
)))
188 return ((uint64_t) ts
.tv_sec
* 1000000000ULL) + ts
.tv_nsec
;
191 #elif defined(CONFIG_RCU_HAVE_CLOCK_GETTIME)
196 typedef uint64_t caa_cycles_t
;
198 static inline caa_cycles_t
caa_get_cycles (void)
202 if (caa_unlikely(clock_gettime(CLOCK_MONOTONIC
, &ts
)))
204 return ((uint64_t) ts
.tv_sec
* 1000000000ULL) + ts
.tv_nsec
;
209 #error caa_get_cycles() not implemented for this platform.
213 #endif /* HAS_CAA_GET_CYCLES */
219 #endif /* _URCU_ARCH_GENERIC_H */