sysdeps/x86/dl-get-cpu-features.c

   1 /* Initialize CPU feature data via IFUNC relocation.
   2    Copyright (C) 2015-2022 Free Software Foundation, Inc.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18
  19 #include <ldsodefs.h>
  20
  21 #ifdef SHARED
  22 # include <cpu-features.c>
  23 # include <gcc-macros.h>
  24
  25 /* NB: Normally, DL_PLATFORM_INIT calls init_cpu_features to initialize
  26    CPU features in dynamic executable.  But when loading ld.so inside of
  27    static executable, DL_PLATFORM_INIT isn't called and IFUNC relocation
  28    is used to call init_cpu_features.  In static executable, it is called
  29    once by IFUNC relocation.  In dynamic executable, it is called twice
  30    by DL_PLATFORM_INIT and by IFUNC relocation.  */
  31 extern void __x86_cpu_features (void) attribute_hidden;
  32 void (*const __x86_cpu_features_p) (void) attribute_hidden
  33   = __x86_cpu_features;
  34
  35 void
  36 _dl_x86_init_cpu_features (void)
  37 {
  38   struct cpu_features *cpu_features = __get_cpu_features ();
  39   if (cpu_features->basic.kind == arch_kind_unknown)
  40     {
  41       init_cpu_features (cpu_features);
  42
  43 # if IS_IN (rtld)
  44       /* See isa-level.c.  */
  45 #  if defined GCCMACRO__GCC_HAVE_SYNC_COMPARE_AND_SWAP_16               \
  46   && defined HAVE_X86_LAHF_SAHF && defined GCCMACRO__POPCNT__           \
  47   && defined GCCMACRO__SSE3__ && defined GCCMACRO__SSSE3__              \
  48   && defined GCCMACRO__SSE4_1__ && defined GCCMACRO__SSE4_2__
  49       if (!(cpu_features->isa_1 & GNU_PROPERTY_X86_ISA_1_V2))
  50         _dl_fatal_printf ("\
  51 Fatal glibc error: CPU does not support x86-64-v%d\n", 2);
  52 #   if defined GCCMACRO__AVX__ && defined GCCMACRO__AVX2__ \
  53   && defined GCCMACRO__F16C__ && defined GCCMACRO__FMA__   \
  54   && defined GCCMACRO__LZCNT__ && defined HAVE_X86_MOVBE
  55       if (!(cpu_features->isa_1 & GNU_PROPERTY_X86_ISA_1_V3))
  56         _dl_fatal_printf ("\
  57 Fatal glibc error: CPU does not support x86-64-v%d\n", 3);
  58 #    if defined GCCMACRO__AVX512F__ && defined GCCMACRO__AVX512BW__ \
  59      && defined GCCMACRO__AVX512CD__ && defined GCCMACRO__AVX512DQ__ \
  60      && defined GCCMACRO__AVX512VL__
  61       if (!(cpu_features->isa_1 & GNU_PROPERTY_X86_ISA_1_V4))
  62         _dl_fatal_printf ("\
  63 Fatal glibc error: CPU does not support x86-64-v%d\n", 4);
  64 #    endif /* ISA level 4 */
  65 #   endif /* ISA level 3 */
  66 #  endif /* ISA level 2 */
  67 # endif /* IS_IN (rtld) */
  68     }
  69 }
  70
  71 __ifunc (__x86_cpu_features, __x86_cpu_features, NULL, void,
  72          _dl_x86_init_cpu_features);
  73 #endif
  74
  75 #undef _dl_x86_get_cpu_features
  76
  77 const struct cpu_features *
  78 _dl_x86_get_cpu_features (void)
  79 {
  80   return &GLRO(dl_x86_cpu_features);
  81 }