config/cet.m4

   1 dnl
   2 dnl GCC_CET_FLAGS
   3 dnl    (SHELL-CODE_HANDLER)
   4 dnl
   5 AC_DEFUN([GCC_CET_FLAGS],[dnl
   6 GCC_ENABLE(cet, no, ,[enable Intel CET in target libraries],
   7            permit yes|no|auto)
   8 AC_MSG_CHECKING([for CET support])
   9
  10 case "$host" in
  11   i[[34567]]86-*-linux* | x86_64-*-linux*)
  12     case "$enable_cet" in
  13       auto)
  14         # Check if target supports multi-byte NOPs
  15         # and if assembler supports CET insn.
  16         AC_COMPILE_IFELSE(
  17          [AC_LANG_PROGRAM(
  18           [],
  19           [
  20 #if !defined(__SSE2__)
  21 #error target does not support multi-byte NOPs
  22 #else
  23 asm ("setssbsy");
  24 #endif
  25           ])],
  26          [enable_cet=yes],
  27          [enable_cet=no])
  28         ;;
  29       yes)
  30         # Check if assembler supports CET.
  31         AC_COMPILE_IFELSE(
  32          [AC_LANG_PROGRAM(
  33           [],
  34           [asm ("setssbsy");])],
  35          [],
  36          [AC_MSG_ERROR([assembler with CET support is required for --enable-cet])])
  37         ;;
  38     esac
  39     ;;
  40   *)
  41     enable_cet=no
  42     ;;
  43 esac
  44 if test x$enable_cet = xyes; then
  45   $1="-fcf-protection -mshstk"
  46   AC_MSG_RESULT([yes])
  47 else
  48   AC_MSG_RESULT([no])
  49 fi
  50 ])