1 /* Copyright (C) 2018 Wildfire Games.
2 *
3 * Permission is hereby granted, free of charge, to any person obtaining
4 * a copy of this software and associated documentation files (the
5 * "Software"), to deal in the Software without restriction, including
6 * without limitation the rights to use, copy, modify, merge, publish,
7 * distribute, sublicense, and/or sell copies of the Software, and to
8 * permit persons to whom the Software is furnished to do so, subject to
9 * the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included
12 * in all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
15 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
17 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
18 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
19 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
20 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21 */
22
23 #include "precompiled.h"
24 #include "lib/allocators/page_aligned.h"
25
26 #include "lib/alignment.h"
27 #include "lib/sysdep/cpu.h" // cpu_CAS
28
29
30 //-----------------------------------------------------------------------------
31
StatusFromMap(void * ret)32 static inline Status StatusFromMap(void* ret)
33 {
34 if(ret != MAP_FAILED)
35 return INFO::OK;
36 WARN_RETURN(StatusFromErrno());
37 }
38
39 // "anonymous" effectively means mapping /dev/zero, but is more efficient.
40 // MAP_ANONYMOUS is not in SUSv3, but is a very common extension.
41 // unfortunately, MacOS X only defines MAP_ANON, which Solaris says is
42 // deprecated. workaround there: define MAP_ANONYMOUS in terms of MAP_ANON.
43 #ifndef MAP_ANONYMOUS
44 # define MAP_ANONYMOUS MAP_ANON
45 #endif
46
47 static const int mmap_flags = MAP_PRIVATE|MAP_ANONYMOUS;
48
mem_Reserve(size_t size,u8 ** pp)49 Status mem_Reserve(size_t size, u8** pp)
50 {
51 errno = 0;
52 void* ret = mmap(0, size, PROT_NONE, mmap_flags, -1, 0);
53 *pp = (u8*)ret;
54 return StatusFromMap(ret);
55 }
56
mem_Release(u8 * p,size_t size)57 Status mem_Release(u8* p, size_t size)
58 {
59 errno = 0;
60 if(munmap(p, size) != 0)
61 WARN_RETURN(StatusFromErrno());
62 return 0;
63 }
64
mem_Commit(u8 * p,size_t size,int prot)65 Status mem_Commit(u8* p, size_t size, int prot)
66 {
67 // avoid misinterpretation by mmap.
68 if(prot == PROT_NONE)
69 WARN_RETURN(ERR::INVALID_PARAM);
70
71 errno = 0;
72 void* ret = mmap(p, size, prot, mmap_flags|MAP_FIXED, -1, 0);
73 return StatusFromMap(ret);
74 }
75
mem_Decommit(u8 * p,size_t size)76 Status mem_Decommit(u8* p, size_t size)
77 {
78 errno = 0;
79 void* ret = mmap(p, size, PROT_NONE, mmap_flags|MAP_FIXED, -1, 0);
80 return StatusFromMap(ret);
81 }
82
mem_Protect(u8 * p,size_t size,int prot)83 Status mem_Protect(u8* p, size_t size, int prot)
84 {
85 errno = 0;
86 if(mprotect(p, size, prot) != 0)
87 WARN_RETURN(StatusFromErrno());
88 return 0;
89
90 }
91
92
93 //-----------------------------------------------------------------------------
94
page_aligned_alloc(size_t size)95 void* page_aligned_alloc(size_t size)
96 {
97 const size_t alignedSize = Align<g_PageSize>(size);
98 u8* p = 0;
99 RETURN_0_IF_ERR(mem_Reserve(alignedSize, &p));
100 RETURN_0_IF_ERR(mem_Commit(p, alignedSize, PROT_READ|PROT_WRITE));
101 return p;
102 }
103
104
page_aligned_free(void * p,size_t size)105 void page_aligned_free(void* p, size_t size)
106 {
107 if(!p)
108 return;
109 ENSURE(IsAligned(p, g_PageSize));
110 const size_t alignedSize = Align<g_PageSize>(size);
111 (void)mem_Release((u8*)p, alignedSize);
112 }
113