1  /* Initialize CPU feature data via IFUNC relocation.
       2     Copyright (C) 2015-2023 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  }