util/cpuinfo-aarch64.c

   1 /*
   2  * SPDX-License-Identifier: GPL-2.0-or-later
   3  * Host specific cpu indentification for AArch64.
   4  */
   5
   6 #include "qemu/osdep.h"
   7 #include "host/cpuinfo.h"
   8
   9 #ifdef CONFIG_LINUX
  10 # ifdef CONFIG_GETAUXVAL
  11 #  include <sys/auxv.h>
  12 # else
  13 #  include <asm/hwcap.h>
  14 #  include "elf.h"
  15 # endif
  16 #endif
  17 #ifdef CONFIG_DARWIN
  18 # include <sys/sysctl.h>
  19 #endif
  20
  21 unsigned cpuinfo;
  22
  23 #ifdef CONFIG_DARWIN
  24 static bool sysctl_for_bool(const char *name)
  25 {
  26     int val = 0;
  27     size_t len = sizeof(val);
  28
  29     if (sysctlbyname(name, &val, &len, NULL, 0) == 0) {
  30         return val != 0;
  31     }
  32
  33     /*
  34      * We might in the future ask for properties not present in older kernels,
  35      * but we're only asking about static properties, all of which should be
  36      * 'int'.  So we shouln't see ENOMEM (val too small), or any of the other
  37      * more exotic errors.
  38      */
  39     assert(errno == ENOENT);
  40     return false;
  41 }
  42 #endif
  43
  44 /* Called both as constructor and (possibly) via other constructors. */
  45 unsigned __attribute__((constructor)) cpuinfo_init(void)
  46 {
  47     unsigned info = cpuinfo;
  48
  49     if (info) {
  50         return info;
  51     }
  52
  53     info = CPUINFO_ALWAYS;
  54
  55 #ifdef CONFIG_LINUX
  56     unsigned long hwcap = qemu_getauxval(AT_HWCAP);
  57     info |= (hwcap & HWCAP_ATOMICS ? CPUINFO_LSE : 0);
  58     info |= (hwcap & HWCAP_USCAT ? CPUINFO_LSE2 : 0);
  59     info |= (hwcap & HWCAP_AES ? CPUINFO_AES: 0);
  60 #endif
  61 #ifdef CONFIG_DARWIN
  62     info |= sysctl_for_bool("hw.optional.arm.FEAT_LSE") * CPUINFO_LSE;
  63     info |= sysctl_for_bool("hw.optional.arm.FEAT_LSE2") * CPUINFO_LSE2;
  64     info |= sysctl_for_bool("hw.optional.arm.FEAT_AES") * CPUINFO_AES;
  65 #endif
  66
  67     cpuinfo = info;
  68     return info;
  69 }