mono/utils/mono-hwcap-arm.c

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