1 /**************************************************************************
2 *
3 * Copyright 2008-2010 VMware, Inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28
29 /*
30 * Memory alignment wrappers.
31 */
32
33
34 #ifndef _OS_MEMORY_H_
35 #error "Must not be included directly. Include os_memory.h instead"
36 #endif
37
38
39 /**
40 * Add two size_t values with integer overflow check.
41 * TODO: leverage __builtin_add_overflow where available
42 */
43 static inline bool
add_overflow_size_t(size_t a,size_t b,size_t * res)44 add_overflow_size_t(size_t a, size_t b, size_t *res)
45 {
46 *res = a + b;
47 return *res < a || *res < b;
48 }
49
50
51 #if defined(HAVE_POSIX_MEMALIGN)
52
53 static inline void *
os_malloc_aligned(size_t size,size_t alignment)54 os_malloc_aligned(size_t size, size_t alignment)
55 {
56 void *ptr;
57 alignment = (alignment + sizeof(void*) - 1) & ~(sizeof(void*) - 1);
58 if(posix_memalign(&ptr, alignment, size) != 0)
59 return NULL;
60 return ptr;
61 }
62
63 #define os_free_aligned(_ptr) free(_ptr)
64
65 #else
66
67 /**
68 * Return memory on given byte alignment
69 */
70 static inline void *
os_malloc_aligned(size_t size,size_t alignment)71 os_malloc_aligned(size_t size, size_t alignment)
72 {
73 char *ptr, *buf;
74 size_t alloc_size;
75
76 /*
77 * Calculate
78 *
79 * alloc_size = size + alignment + sizeof(void *)
80 *
81 * while checking for overflow.
82 */
83 if (add_overflow_size_t(size, alignment, &alloc_size) ||
84 add_overflow_size_t(alloc_size, sizeof(void *), &alloc_size)) {
85 return NULL;
86 }
87
88 ptr = (char *) os_malloc(alloc_size);
89 if (!ptr)
90 return NULL;
91
92 buf = (char *)(((uintptr_t)ptr + sizeof(void *) + alignment - 1) & ~((uintptr_t)(alignment - 1)));
93 *(char **)(buf - sizeof(void *)) = ptr;
94
95 return buf;
96 }
97
98
99 /**
100 * Free memory returned by os_malloc_aligned().
101 */
102 static inline void
os_free_aligned(void * ptr)103 os_free_aligned(void *ptr)
104 {
105 if (ptr) {
106 void **cubbyHole = (void **) ((char *) ptr - sizeof(void *));
107 void *realAddr = *cubbyHole;
108 os_free(realAddr);
109 }
110 }
111
112 #endif
113
114 /**
115 * Reallocate memeory, with alignment
116 */
117 static inline void *
os_realloc_aligned(void * ptr,size_t oldsize,size_t newsize,size_t alignment)118 os_realloc_aligned(void *ptr, size_t oldsize, size_t newsize, size_t alignment)
119 {
120 const size_t copySize = MIN2(oldsize, newsize);
121 void *newBuf = os_malloc_aligned(newsize, alignment);
122 if (newBuf && ptr && copySize > 0) {
123 memcpy(newBuf, ptr, copySize);
124 }
125
126 os_free_aligned(ptr);
127 return newBuf;
128 }
129