xref: /openbmc/qemu/util/memalign.c (revision b86c6ba6)
1 /*
2  * memalign.c: Allocate an aligned memory region
3  *
4  * Copyright (c) 2003-2008 Fabrice Bellard
5  * Copyright (c) 2010-2016 Red Hat, Inc.
6  * Copyright (c) 2022 Linaro Ltd
7  *
8  * Permission is hereby granted, free of charge, to any person obtaining a copy
9  * of this software and associated documentation files (the "Software"), to deal
10  * in the Software without restriction, including without limitation the rights
11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12  * copies of the Software, and to permit persons to whom the Software is
13  * furnished to do so, subject to the following conditions:
14  *
15  * The above copyright notice and this permission notice shall be included in
16  * all copies or substantial portions of the Software.
17  *
18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24  * THE SOFTWARE.
25  */
26 
27 #include "qemu/osdep.h"
28 #include "qemu/host-utils.h"
29 #include "qemu/memalign.h"
30 #include "trace.h"
31 
32 void *qemu_try_memalign(size_t alignment, size_t size)
33 {
34     void *ptr;
35 
36     if (alignment < sizeof(void*)) {
37         alignment = sizeof(void*);
38     } else {
39         g_assert(is_power_of_2(alignment));
40     }
41 
42     /*
43      * Handling of 0 allocations varies among the different
44      * platform APIs (for instance _aligned_malloc() will
45      * fail) -- ensure that we always return a valid non-NULL
46      * pointer that can be freed by qemu_vfree().
47      */
48     if (size == 0) {
49         size++;
50     }
51 #if defined(CONFIG_POSIX_MEMALIGN)
52     int ret;
53     ret = posix_memalign(&ptr, alignment, size);
54     if (ret != 0) {
55         errno = ret;
56         ptr = NULL;
57     }
58 #elif defined(CONFIG_ALIGNED_MALLOC)
59     ptr = _aligned_malloc(size, alignment);
60 #elif defined(CONFIG_VALLOC)
61     ptr = valloc(size);
62 #elif defined(CONFIG_MEMALIGN)
63     ptr = memalign(alignment, size);
64 #else
65     #error No function to allocate aligned memory available
66 #endif
67     trace_qemu_memalign(alignment, size, ptr);
68     return ptr;
69 }
70 
71 void *qemu_memalign(size_t alignment, size_t size)
72 {
73     void *p = qemu_try_memalign(alignment, size);
74     if (p) {
75         return p;
76     }
77     fprintf(stderr,
78             "qemu_memalign: failed to allocate %zu bytes at alignment %zu: %s\n",
79             size, alignment, strerror(errno));
80     abort();
81 }
82 
83 void qemu_vfree(void *ptr)
84 {
85     trace_qemu_vfree(ptr);
86 #if !defined(CONFIG_POSIX_MEMALIGN) && defined(CONFIG_ALIGNED_MALLOC)
87     /* Only Windows _aligned_malloc needs a special free function */
88     _aligned_free(ptr);
89 #else
90     free(ptr);
91 #endif
92 }
93