util/memalign.c

   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 }