mono/utils/mono-hwcap-arm.c

   1 /**
   2  * \file
   3  * ARM hardware feature detection
   4  *
   5  * Authors:
   6  *    Alex Rønne Petersen (alexrp@xamarin.com)
   7  *    Elijah Taylor (elijahtaylor@google.com)
   8  *    Miguel de Icaza (miguel@xamarin.com)
   9  *    Neale Ferguson (Neale.Ferguson@SoftwareAG-usa.com)
  10  *    Paolo Molaro (lupus@xamarin.com)
  11  *    Rodrigo Kumpera (kumpera@gmail.com)
  12  *    Sebastien Pouliot (sebastien@xamarin.com)
  13  *    Zoltan Varga (vargaz@xamarin.com)
  14  *
  15  * Copyright 2003 Ximian, Inc.
  16  * Copyright 2003-2011 Novell, Inc
  17  * Copyright 2006 Broadcom
  18  * Copyright 2007-2008 Andreas Faerber
  19  * Copyright 2011-2013 Xamarin Inc
  20  * Licensed under the MIT license. See LICENSE file in the project root for full license information.
  21  */
  22
  23 #include "mono/utils/mono-hwcap.h"
  24
  25 #if defined(HAVE_SYS_AUXV_H) && !defined(PLATFORM_ANDROID)
  26 #include <sys/auxv.h>
  27 #elif defined(__APPLE__)
  28 #include <mach/machine.h>
  29 #include <sys/sysctl.h>
  30 #include <sys/types.h>
  31 #else
  32 #if defined (HAVE_SYS_UTSNAME_H)
  33 #include <sys/utsname.h>
  34 #endif
  35 #include <stdio.h>
  36 #endif
  37
  38 void
  39 mono_hwcap_arch_init (void)
  40 {
  41 #if defined(HAVE_SYS_AUXV_H) && !defined(PLATFORM_ANDROID)
  42         unsigned long hwcap;
  43         unsigned long platform;
  44
  45         if ((hwcap = getauxval(AT_HWCAP))) {
  46                 /* HWCAP_ARM_THUMB */
  47                 if (hwcap & 0x00000004)
  48                         mono_hwcap_arm_has_thumb = TRUE;
  49
  50                 /* HWCAP_ARM_VFP */
  51                 if (hwcap & 0x00000040)
  52                         mono_hwcap_arm_has_vfp = TRUE;
  53
  54                 /* HWCAP_ARM_VFPv3 */
  55                 if (hwcap & 0x00002000)
  56                         mono_hwcap_arm_has_vfp3 = TRUE;
  57
  58                 /* HWCAP_ARM_VFPv3D16 */
  59                 if (hwcap & 0x00004000)
  60                         mono_hwcap_arm_has_vfp3_d16 = TRUE;
  61
  62                 /* TODO: Find a way to detect Thumb 2. */
  63         }
  64
  65         if ((platform = getauxval(AT_PLATFORM))) {
  66                 const char *str = (const char *) platform;
  67
  68                 if (str [1] >= '5')
  69                         mono_hwcap_arm_is_v5 = TRUE;
  70
  71                 if (str [1] >= '6')
  72                         mono_hwcap_arm_is_v6 = TRUE;
  73
  74                 if (str [1] >= '7')
  75                         mono_hwcap_arm_is_v7 = TRUE;
  76
  77                 /* TODO: Find a way to detect v7s. */
  78         }
  79 #elif defined(__APPLE__)
  80         cpu_subtype_t sub_type;
  81         size_t length = sizeof (sub_type);
  82
  83         sysctlbyname ("hw.cpusubtype", &sub_type, &length, NULL, 0);
  84
  85         if (sub_type == CPU_SUBTYPE_ARM_V5TEJ || sub_type == CPU_SUBTYPE_ARM_XSCALE) {
  86                 mono_hwcap_arm_is_v5 = TRUE;
  87         } else if (sub_type == CPU_SUBTYPE_ARM_V6) {
  88                 mono_hwcap_arm_is_v5 = TRUE;
  89                 mono_hwcap_arm_is_v6 = TRUE;
  90         } else if (sub_type == CPU_SUBTYPE_ARM_V7 || sub_type == CPU_SUBTYPE_ARM_V7F || sub_type == CPU_SUBTYPE_ARM_V7K) {
  91                 mono_hwcap_arm_is_v5 = TRUE;
  92                 mono_hwcap_arm_is_v6 = TRUE;
  93                 mono_hwcap_arm_is_v7 = TRUE;
  94         }
  95
  96         /* TODO: Find a way to detect features like Thumb and VFP. */
  97 #else
  98         /* We can't use the auxiliary vector on Android due to
  99          * permissions, so fall back to /proc/cpuinfo. We also
 100          * hit this path if the target doesn't have sys/auxv.h.
 101          */
 102
 103 #if defined (HAVE_SYS_UTSNAME_H)
 104         struct utsname name;
 105
 106         /* Only fails if `name` is invalid (it isn't). */
 107         g_assert (!uname (&name));
 108
 109         if (!strncmp (name.machine, "aarch64", 7) || !strncmp (name.machine, "armv8", 5)) {
 110                 /*
 111                  * We're a 32-bit program running on an ARMv8 system.
 112                  * Whether the system is actually 32-bit or 64-bit
 113                  * doesn't matter to us. The important thing is that
 114                  * all 3 of ARMv8's execution states (A64, A32, T32)
 115                  * are guaranteed to have all of the features that
 116                  * we want to detect and use.
 117                  *
 118                  * We do this ARMv8 detection via uname () because
 119                  * in the early days of ARMv8 on Linux, the
 120                  * /proc/cpuinfo format was a disaster and there
 121                  * were multiple (merged into mainline) attempts at
 122                  * cleaning it up (read: breaking applications that
 123                  * tried to rely on it). So now multiple ARMv8
 124                  * systems in the wild have different /proc/cpuinfo
 125                  * output, some of which are downright useless.
 126                  *
 127                  * So, when it comes to detecting ARMv8 in a 32-bit
 128                  * program, it's better to just avoid /proc/cpuinfo
 129                  * entirely. Maybe in a decade or two, we won't
 130                  * have to worry about this mess that the Linux ARM
 131                  * maintainers created. One can hope.
 132                  */
 133
 134                 mono_hwcap_arm_is_v5 = TRUE;
 135                 mono_hwcap_arm_is_v6 = TRUE;
 136                 mono_hwcap_arm_is_v7 = TRUE;
 137
 138                 mono_hwcap_arm_has_vfp = TRUE;
 139                 mono_hwcap_arm_has_vfp3 = TRUE;
 140                 mono_hwcap_arm_has_vfp3_d16 = TRUE;
 141
 142                 mono_hwcap_arm_has_thumb = TRUE;
 143                 mono_hwcap_arm_has_thumb2 = TRUE;
 144         }
 145 #endif
 146
 147         char buf [512];
 148         char *line;
 149
 150         FILE *file = fopen ("/proc/cpuinfo", "r");
 151
 152         if (file) {
 153                 while ((line = fgets (buf, 512, file))) {
 154                         if (!strncmp (line, "Processor", 9) ||
 155                             !strncmp (line, "model name", 10)) {
 156                                 char *ver = strstr (line, "(v");
 157
 158                                 if (ver) {
 159                                         if (ver [2] >= '5')
 160                                                 mono_hwcap_arm_is_v5 = TRUE;
 161
 162                                         if (ver [2] >= '6')
 163                                                 mono_hwcap_arm_is_v6 = TRUE;
 164
 165                                         if (ver [2] >= '7')
 166                                                 mono_hwcap_arm_is_v7 = TRUE;
 167
 168                                         /* TODO: Find a way to detect v7s. */
 169                                 }
 170
 171                                 continue;
 172                         }
 173
 174                         if (!strncmp (line, "Features", 8)) {
 175                                 if (strstr (line, "thumb"))
 176                                         mono_hwcap_arm_has_thumb = TRUE;
 177
 178                                 /* TODO: Find a way to detect Thumb 2. */
 179
 180                                 if (strstr (line, "vfp"))
 181                                         mono_hwcap_arm_has_vfp = TRUE;
 182
 183                                 if (strstr (line, "vfpv3"))
 184                                         mono_hwcap_arm_has_vfp3 = TRUE;
 185
 186                                 if (strstr (line, "vfpv3-d16"))
 187                                         mono_hwcap_arm_has_vfp3_d16 = TRUE;
 188
 189                                 continue;
 190                         }
 191                 }
 192
 193                 fclose (file);
 194         }
 195 #endif
 196 }