1 /*
2 *
3 * Copyright 2015 gRPC authors.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19 #ifndef GRPC_IMPL_CODEGEN_ATM_GCC_SYNC_H
20 #define GRPC_IMPL_CODEGEN_ATM_GCC_SYNC_H
21
22 /* variant of atm_platform.h for gcc and gcc-like compiers with __sync_*
23 interface */
24 #include <grpc/impl/codegen/port_platform.h>
25
26 typedef intptr_t gpr_atm;
27 #define GPR_ATM_MAX INTPTR_MAX
28 #define GPR_ATM_MIN INTPTR_MIN
29 #define GPR_ATM_INC_CAS_THEN(blah) blah
30 #define GPR_ATM_INC_ADD_THEN(blah) blah
31
32 #define GPR_ATM_COMPILE_BARRIER_() __asm__ __volatile__("" : : : "memory")
33
34 #if defined(__i386) || defined(__x86_64__)
35 /* All loads are acquire loads and all stores are release stores. */
36 #define GPR_ATM_LS_BARRIER_() GPR_ATM_COMPILE_BARRIER_()
37 #else
38 #define GPR_ATM_LS_BARRIER_() gpr_atm_full_barrier()
39 #endif
40
41 #define gpr_atm_full_barrier() (__sync_synchronize())
42
gpr_atm_acq_load(const gpr_atm * p)43 static __inline gpr_atm gpr_atm_acq_load(const gpr_atm* p) {
44 gpr_atm value = *p;
45 GPR_ATM_LS_BARRIER_();
46 return value;
47 }
48
gpr_atm_no_barrier_load(const gpr_atm * p)49 static __inline gpr_atm gpr_atm_no_barrier_load(const gpr_atm* p) {
50 gpr_atm value = *p;
51 GPR_ATM_COMPILE_BARRIER_();
52 return value;
53 }
54
gpr_atm_rel_store(gpr_atm * p,gpr_atm value)55 static __inline void gpr_atm_rel_store(gpr_atm* p, gpr_atm value) {
56 GPR_ATM_LS_BARRIER_();
57 *p = value;
58 }
59
gpr_atm_no_barrier_store(gpr_atm * p,gpr_atm value)60 static __inline void gpr_atm_no_barrier_store(gpr_atm* p, gpr_atm value) {
61 GPR_ATM_COMPILE_BARRIER_();
62 *p = value;
63 }
64
65 #undef GPR_ATM_LS_BARRIER_
66 #undef GPR_ATM_COMPILE_BARRIER_
67
68 #define gpr_atm_no_barrier_fetch_add(p, delta) \
69 gpr_atm_full_fetch_add((p), (delta))
70 #define gpr_atm_full_fetch_add(p, delta) (__sync_fetch_and_add((p), (delta)))
71
72 #define gpr_atm_no_barrier_cas(p, o, n) gpr_atm_acq_cas((p), (o), (n))
73 #define gpr_atm_acq_cas(p, o, n) (__sync_bool_compare_and_swap((p), (o), (n)))
74 #define gpr_atm_rel_cas(p, o, n) gpr_atm_acq_cas((p), (o), (n))
75 #define gpr_atm_full_cas(p, o, n) gpr_atm_acq_cas((p), (o), (n))
76
gpr_atm_full_xchg(gpr_atm * p,gpr_atm n)77 static __inline gpr_atm gpr_atm_full_xchg(gpr_atm* p, gpr_atm n) {
78 gpr_atm cur;
79 do {
80 cur = gpr_atm_acq_load(p);
81 } while (!gpr_atm_rel_cas(p, cur, n));
82 return cur;
83 }
84
85 #endif /* GRPC_IMPL_CODEGEN_ATM_GCC_SYNC_H */
86