1 | /*************************************************************************** |
2 | * _ _ ____ _ |
3 | * Project ___| | | | _ \| | |
4 | * / __| | | | |_) | | |
5 | * | (__| |_| | _ <| |___ |
6 | * \___|\___/|_| \_\_____| |
7 | * |
8 | * Copyright (C) 1998 - 2022, Daniel Stenberg, <[email protected]>, et al. |
9 | * |
10 | * This software is licensed as described in the file COPYING, which |
11 | * you should have received as part of this distribution. The terms |
12 | * are also available at https://curl.se/docs/copyright.html. |
13 | * |
14 | * You may opt to use, copy, modify, merge, publish, distribute and/or sell |
15 | * copies of the Software, and permit persons to whom the Software is |
16 | * furnished to do so, under the terms of the COPYING file. |
17 | * |
18 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY |
19 | * KIND, either express or implied. |
20 | * |
21 | * SPDX-License-Identifier: curl |
22 | * |
23 | ***************************************************************************/ |
24 | |
25 | #include "curl_setup.h" |
26 | |
27 | #define GLOBAL_INIT_IS_THREADSAFE |
28 | |
29 | #if defined(_WIN32_WINNT) && _WIN32_WINNT >= 0x600 |
30 | |
31 | #ifdef __MINGW32__ |
32 | #ifndef __MINGW64_VERSION_MAJOR |
33 | #if (__MINGW32_MAJOR_VERSION < 5) || \ |
34 | (__MINGW32_MAJOR_VERSION == 5 && __MINGW32_MINOR_VERSION == 0) |
35 | /* mingw >= 5.0.1 defines SRWLOCK, and slightly different from MS define */ |
36 | typedef PVOID SRWLOCK, *PSRWLOCK; |
37 | #endif |
38 | #endif |
39 | #ifndef SRWLOCK_INIT |
40 | #define SRWLOCK_INIT NULL |
41 | #endif |
42 | #endif /* __MINGW32__ */ |
43 | |
44 | #define curl_simple_lock SRWLOCK |
45 | #define CURL_SIMPLE_LOCK_INIT SRWLOCK_INIT |
46 | |
47 | #define curl_simple_lock_lock(m) AcquireSRWLockExclusive(m) |
48 | #define curl_simple_lock_unlock(m) ReleaseSRWLockExclusive(m) |
49 | |
50 | #elif defined (HAVE_ATOMIC) |
51 | #include <stdatomic.h> |
52 | #if defined(HAVE_SCHED_YIELD) |
53 | #include <sched.h> |
54 | #endif |
55 | |
56 | #define curl_simple_lock atomic_int |
57 | #define CURL_SIMPLE_LOCK_INIT 0 |
58 | |
59 | /* a clang-thing */ |
60 | #ifndef __has_builtin |
61 | #define __has_builtin(x) 0 |
62 | #endif |
63 | |
64 | #ifndef __INTEL_COMPILER |
65 | /* The Intel compiler tries to look like GCC *and* clang *and* lies in its |
66 | __has_builtin() function, so override it. */ |
67 | |
68 | /* if GCC on i386/x86_64 or if the built-in is present */ |
69 | #if ( (defined(__GNUC__) && !defined(__clang__)) && \ |
70 | (defined(__i386__) || defined(__x86_64__))) || \ |
71 | __has_builtin(__builtin_ia32_pause) |
72 | #define HAVE_BUILTIN_IA32_PAUSE |
73 | #endif |
74 | |
75 | #endif |
76 | |
77 | static inline void curl_simple_lock_lock(curl_simple_lock *lock) |
78 | { |
79 | for(;;) { |
80 | if(!atomic_exchange_explicit(lock, true, memory_order_acquire)) |
81 | break; |
82 | /* Reduce cache coherency traffic */ |
83 | while(atomic_load_explicit(lock, memory_order_relaxed)) { |
84 | /* Reduce load (not mandatory) */ |
85 | #ifdef HAVE_BUILTIN_IA32_PAUSE |
86 | __builtin_ia32_pause(); |
87 | #elif defined(__aarch64__) |
88 | __asm__ volatile("yield" ::: "memory" ); |
89 | #elif defined(HAVE_SCHED_YIELD) |
90 | sched_yield(); |
91 | #endif |
92 | } |
93 | } |
94 | } |
95 | |
96 | static inline void curl_simple_lock_unlock(curl_simple_lock *lock) |
97 | { |
98 | atomic_store_explicit(lock, false, memory_order_release); |
99 | } |
100 | |
101 | #else |
102 | |
103 | #undef GLOBAL_INIT_IS_THREADSAFE |
104 | |
105 | #endif |
106 | |