1  /* Support for GNU properties in ldconfig.  x86 version.
       2     Copyright (C) 2021-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #ifndef _ELF_READ_PROP_H
      20  #define _ELF_READ_PROP_H
      21  
      22  #include <dl-cache.h>
      23  
      24  /* Called for each property in the NT_GNU_PROPERTY_TYPE_0 note of SEGMENT.
      25     Return value:
      26       false: Continue processing the properties.
      27       true : Stop processing the properties.
      28   */
      29  static inline bool __attribute__ ((always_inline))
      30  read_gnu_property (unsigned int *isal_level, uint32_t type,
      31  		   uint32_t datasz, void *data)
      32  {
      33    /* Property type must be in ascending order.  */
      34    if (type > GNU_PROPERTY_X86_ISA_1_NEEDED)
      35      return true;
      36  
      37    if (type == GNU_PROPERTY_X86_ISA_1_NEEDED)
      38      {
      39        if (datasz == 4)
      40  	{
      41  	  /* The size of GNU_PROPERTY_X86_ISA_1_NEEDED must be 4 bytes.
      42  	     There is no point to continue if this type is ill-formed.  */
      43  	  unsigned int isa_1_needed = *(unsigned int *) data;
      44  	  _Static_assert (((sizeof (isa_1_needed) * 8)
      45  			   <= (1 << DL_CACHE_HWCAP_ISA_LEVEL_COUNT)),
      46  			  "DL_CACHE_HWCAP_ISA_LEVEL_COUNT is too small");
      47  	  if (isa_1_needed != 0)
      48  	    {
      49  	      unsigned int level;
      50  	      asm ("bsr %1, %0" : "=r" (level) : "g" (isa_1_needed));
      51  	      *isal_level = level;
      52  	    }
      53  	}
      54        return true;
      55      }
      56  
      57    return false;
      58  }
      59  
      60  #endif