sysdeps/aarch64/sys/ifunc.h

   1 /* Definitions used by AArch64 indirect function resolvers.
   2    Copyright (C) 2019-2022 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 _SYS_IFUNC_H
  20 #define _SYS_IFUNC_H
  21
  22 /* A second argument is passed to the ifunc resolver.  */
  23 #define _IFUNC_ARG_HWCAP        (1ULL << 62)
  24
  25 /* The prototype of a gnu indirect function resolver on AArch64 is
  26
  27      ElfW(Addr) ifunc_resolver (uint64_t, const __ifunc_arg_t *);
  28
  29    the first argument should have the _IFUNC_ARG_HWCAP bit set and
  30    the remaining bits should match the AT_HWCAP settings.  */
  31
  32 /* Second argument to an ifunc resolver.  */
  33 struct __ifunc_arg_t
  34 {
  35   unsigned long _size; /* Size of the struct, so it can grow.  */
  36   unsigned long _hwcap;
  37   unsigned long _hwcap2;
  38 };
  39
  40 typedef struct __ifunc_arg_t __ifunc_arg_t;
  41
  42 #endif