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f1717362 | 1 | /* Copyright (C) 2014-2016 Free Software Foundation, Inc. |
77401673 | 2 | Contributed by Kai Tietz <ktietz@redhat.com>. |
3 | ||
4 | This file is part of the GNU Atomic Library (libatomic). | |
5 | ||
6 | Libatomic is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 3 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | Libatomic is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | |
13 | FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
14 | more details. | |
15 | ||
16 | Under Section 7 of GPL version 3, you are granted additional | |
17 | permissions described in the GCC Runtime Library Exception, version | |
18 | 3.1, as published by the Free Software Foundation. | |
19 | ||
20 | You should have received a copy of the GNU General Public License and | |
21 | a copy of the GCC Runtime Library Exception along with this program; | |
22 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | <http://www.gnu.org/licenses/>. */ | |
24 | ||
25 | #define UWORD __shadow_UWORD | |
26 | #include <windows.h> | |
27 | #undef UWORD | |
28 | #include "libatomic_i.h" | |
29 | ||
30 | /* The target page size. Must be no larger than the runtime page size, | |
31 | lest locking fail with virtual address aliasing (i.e. a page mmaped | |
32 | at two locations). */ | |
33 | #ifndef PAGE_SIZE | |
34 | #define PAGE_SIZE 4096 | |
35 | #endif | |
36 | ||
37 | /* The target cacheline size. This is an optimization; the padding that | |
38 | should be applied to the locks to keep them from interfering. */ | |
39 | #ifndef CACHLINE_SIZE | |
40 | #define CACHLINE_SIZE 64 | |
41 | #endif | |
42 | ||
43 | /* The granularity at which locks are applied. Almost certainly the | |
44 | cachline size is the right thing to use here. */ | |
45 | #ifndef WATCH_SIZE | |
46 | #define WATCH_SIZE CACHLINE_SIZE | |
47 | #endif | |
48 | ||
49 | struct lock | |
50 | { | |
51 | HANDLE mutex; | |
52 | char pad[sizeof (HANDLE) < CACHLINE_SIZE | |
53 | ? CACHLINE_SIZE - sizeof (HANDLE) | |
54 | : 0]; | |
55 | }; | |
56 | ||
57 | #define NLOCKS (PAGE_SIZE / WATCH_SIZE) | |
58 | ||
59 | static struct lock locks[NLOCKS] = { | |
60 | [0 ... NLOCKS-1].mutex = NULL | |
61 | }; | |
62 | ||
63 | static inline uintptr_t | |
64 | addr_hash (void *ptr) | |
65 | { | |
66 | return ((uintptr_t)ptr / WATCH_SIZE) % NLOCKS; | |
67 | } | |
68 | ||
69 | void | |
70 | libat_lock_1 (void *ptr) | |
71 | { | |
72 | if (!locks[addr_hash (ptr)].mutex) | |
73 | locks[addr_hash (ptr)].mutex = CreateMutex (NULL, FALSE, NULL); | |
74 | WaitForSingleObject (locks[addr_hash (ptr)].mutex, INFINITE); | |
75 | } | |
76 | ||
77 | void | |
78 | libat_unlock_1 (void *ptr) | |
79 | { | |
80 | if (locks[addr_hash (ptr)].mutex) | |
81 | ReleaseMutex (locks[addr_hash (ptr)].mutex); | |
82 | } | |
83 | ||
84 | void | |
85 | libat_lock_n (void *ptr, size_t n) | |
86 | { | |
87 | uintptr_t h = addr_hash (ptr); | |
88 | size_t i = 0; | |
89 | ||
90 | /* Don't lock more than all the locks we have. */ | |
91 | if (n > PAGE_SIZE) | |
92 | n = PAGE_SIZE; | |
93 | ||
94 | do | |
95 | { | |
96 | if (!locks[h].mutex) | |
97 | locks[h].mutex = CreateMutex (NULL, FALSE, NULL); | |
98 | WaitForSingleObject (locks[h].mutex, INFINITE); | |
99 | if (++h == NLOCKS) | |
100 | h = 0; | |
101 | i += WATCH_SIZE; | |
102 | } | |
103 | while (i < n); | |
104 | } | |
105 | ||
106 | void | |
107 | libat_unlock_n (void *ptr, size_t n) | |
108 | { | |
109 | uintptr_t h = addr_hash (ptr); | |
110 | size_t i = 0; | |
111 | ||
112 | if (n > PAGE_SIZE) | |
113 | n = PAGE_SIZE; | |
114 | ||
115 | do | |
116 | { | |
117 | if (locks[h].mutex) | |
118 | ReleaseMutex (locks[h].mutex); | |
119 | if (++h == NLOCKS) | |
120 | h = 0; | |
121 | i += WATCH_SIZE; | |
122 | } | |
123 | while (i < n); | |
124 | } |