1  /* Support for GNU properties.  AArch64 version.
       2     Copyright (C) 2018-2023 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 _DL_PROP_H
      20  #define _DL_PROP_H
      21  
      22  extern void _dl_bti_protect (struct link_map *, int) attribute_hidden;
      23  
      24  extern void _dl_bti_check (struct link_map *, const char *)
      25      attribute_hidden;
      26  
      27  static inline void __attribute__ ((always_inline))
      28  _rtld_main_check (struct link_map *m, const char *program)
      29  {
      30    _dl_bti_check (m, program);
      31  }
      32  
      33  static inline void __attribute__ ((always_inline))
      34  _dl_open_check (struct link_map *m)
      35  {
      36    _dl_bti_check (m, NULL);
      37  }
      38  
      39  static inline void __attribute__ ((always_inline))
      40  _dl_process_pt_note (struct link_map *l, int fd, const ElfW(Phdr) *ph)
      41  {
      42  }
      43  
      44  static inline int
      45  _dl_process_gnu_property (struct link_map *l, int fd, uint32_t type,
      46  			  uint32_t datasz, void *data)
      47  {
      48    if (!GLRO(dl_aarch64_cpu_features).bti)
      49      /* Skip note processing.  */
      50      return 0;
      51  
      52    if (type == GNU_PROPERTY_AARCH64_FEATURE_1_AND)
      53      {
      54        /* Stop if the property note is ill-formed.  */
      55        if (datasz != 4)
      56  	return 0;
      57  
      58        unsigned int feature_1 = *(unsigned int *) data;
      59        if (feature_1 & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)
      60  	_dl_bti_protect (l, fd);
      61  
      62        /* Stop if we processed the property note.  */
      63        return 0;
      64      }
      65    /* Continue.  */
      66    return 1;
      67  }
      68  
      69  #endif /* _DL_PROP_H */