Enable building libgcc with CET options.

Enable building libgcc with CET options by default on Linux/x86 if
binutils supports CET v2.0.  It can be disabled with --disable-cet.
It is an error to configure GCC with --enable-cet if bintuiils
doesn't support CET v2.0.

ENDBR instruction is added to __morestack_large_model since it is
called indirectly.

2017-11-17  Igor Tsimbalist  <igor.v.tsimbalist@intel.com>

config/
	* cet.m4: New file.

gcc/
	* config.gcc (extra_headers): Add cet.h for x86 targets.
	* config/i386/cet.h: New file.
	* doc/install.texi: Add --enable-cet/--disable-cet.

libgcc/
	* Makefile.in (configure_deps): Add $(srcdir)/../config/cet.m4.
	(CET_FLAGS): New.
	* config/i386/morestack.S: Include <cet.h>.
	(__morestack_large_model): Add _CET_ENDBR at function entrance.
	* config/i386/resms64.h: Include <cet.h>.
	* config/i386/resms64f.h: Likewise.
	* config/i386/resms64fx.h: Likewise.
	* config/i386/resms64x.h: Likewise.
	* config/i386/savms64.h: Likewise.
	* config/i386/savms64f.h: Likewise.
	* config/i386/t-linux (HOST_LIBGCC2_CFLAGS): Add $(CET_FLAGS).
	(CRTSTUFF_T_CFLAGS): Likewise.
	* configure.ac: Include ../config/cet.m4.
	Set and substitute CET_FLAGS.
	* configure: Regenerated.

From-SVN: r254868

12 files changed, 115 insertions, 2 deletions

diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index a069cd7..da4d1ad 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,21 @@
+2017-11-17  Igor Tsimbalist  <igor.v.tsimbalist@intel.com>
+
+	* Makefile.in (configure_deps): Add $(srcdir)/../config/cet.m4.
+	(CET_FLAGS): New.
+	* config/i386/morestack.S: Include <cet.h>.
+	(__morestack_large_model): Add _CET_ENDBR at function entrance.
+	* config/i386/resms64.h: Include <cet.h>.
+	* config/i386/resms64f.h: Likewise.
+	* config/i386/resms64fx.h: Likewise.
+	* config/i386/resms64x.h: Likewise.
+	* config/i386/savms64.h: Likewise.
+	* config/i386/savms64f.h: Likewise.
+	* config/i386/t-linux (HOST_LIBGCC2_CFLAGS): Add $(CET_FLAGS).
+	(CRTSTUFF_T_CFLAGS): Likewise.
+	* configure.ac: Include ../config/cet.m4.
+	Set and substitute CET_FLAGS.
+	* configure: Regenerated.
+
 2017-11-14  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* config.host (*-*-solaris2*): Adapt comment for Solaris 12
diff --git a/libgcc/Makefile.in b/libgcc/Makefile.in
index a1a392d..eaa68b5 100644
--- a/libgcc/Makefile.in
+++ b/libgcc/Makefile.in
@@ -171,7 +171,8 @@ configure_deps = \
 	$(srcdir)/../config/dfp.m4 \
 	$(srcdir)/../config/unwind_ipinfo.m4 \
 	$(srcdir)/../config/gthr.m4 \
-	$(srcdir)/../config/sjlj.m4
+	$(srcdir)/../config/sjlj.m4 \
+	$(srcdir)/../config/cet.m4
 
 $(srcdir)/configure: @MAINT@ $(srcdir)/configure.ac $(configure_deps)
 	cd $(srcdir) && $(AUTOCONF)
@@ -254,6 +255,8 @@ HOST_LIBGCC2_CFLAGS =
 
 PICFLAG = @PICFLAG@
 
+CET_FLAGS = @CET_FLAGS@
+
 # Defined in libgcc2.c, included only in the static library.
 LIB2FUNCS_ST = _eprintf __gcc_bcmp
 
diff --git a/libgcc/config/i386/morestack.S b/libgcc/config/i386/morestack.S
index 9d185c1..79d5db9 100644
--- a/libgcc/config/i386/morestack.S
+++ b/libgcc/config/i386/morestack.S
@@ -91,6 +91,8 @@
 # __morestack to call __morestack_non_split instead.  We just bump the
 # requested stack space by 16K.
 
+#include <cet.h>
+
 	.global __morestack_non_split
 	.hidden	__morestack_non_split
 
@@ -701,6 +703,7 @@ DW.ref.__gcc_personality_v0:
 __morestack_large_model:
 
 	.cfi_startproc
+	_CET_ENDBR
 
 	movq	%r10, %r11
 	andl	$0xffffffff, %r10d
diff --git a/libgcc/config/i386/resms64.h b/libgcc/config/i386/resms64.h
index f01b418..45a42da 100644
--- a/libgcc/config/i386/resms64.h
+++ b/libgcc/config/i386/resms64.h
@@ -23,6 +23,8 @@ a copy of the GCC Runtime Library Exception along with this program;
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
+#include <cet.h>
+
 #ifdef __x86_64__
 #include "i386-asm.h"
 
diff --git a/libgcc/config/i386/resms64f.h b/libgcc/config/i386/resms64f.h
index 743ec51..00805b3 100644
--- a/libgcc/config/i386/resms64f.h
+++ b/libgcc/config/i386/resms64f.h
@@ -23,6 +23,8 @@ a copy of the GCC Runtime Library Exception along with this program;
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
+#include <cet.h>
+
 #ifdef __x86_64__
 #include "i386-asm.h"
 
diff --git a/libgcc/config/i386/resms64fx.h b/libgcc/config/i386/resms64fx.h
index 965807a..85083cd 100644
--- a/libgcc/config/i386/resms64fx.h
+++ b/libgcc/config/i386/resms64fx.h
@@ -23,6 +23,8 @@ a copy of the GCC Runtime Library Exception along with this program;
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
+#include <cet.h>
+
 #ifdef __x86_64__
 #include "i386-asm.h"
 
diff --git a/libgcc/config/i386/resms64x.h b/libgcc/config/i386/resms64x.h
index 689a1de..fcf885e 100644
--- a/libgcc/config/i386/resms64x.h
+++ b/libgcc/config/i386/resms64x.h
@@ -23,6 +23,8 @@ a copy of the GCC Runtime Library Exception along with this program;
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
+#include <cet.h>
+
 #ifdef __x86_64__
 #include "i386-asm.h"
 
diff --git a/libgcc/config/i386/savms64.h b/libgcc/config/i386/savms64.h
index 28d5e35..570902d 100644
--- a/libgcc/config/i386/savms64.h
+++ b/libgcc/config/i386/savms64.h
@@ -23,6 +23,8 @@ a copy of the GCC Runtime Library Exception along with this program;
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
+#include <cet.h>
+
 #ifdef __x86_64__
 #include "i386-asm.h"
 
diff --git a/libgcc/config/i386/savms64f.h b/libgcc/config/i386/savms64f.h
index 723e108..51c9d97 100644
--- a/libgcc/config/i386/savms64f.h
+++ b/libgcc/config/i386/savms64f.h
@@ -23,6 +23,8 @@ a copy of the GCC Runtime Library Exception along with this program;
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
+#include <cet.h>
+
 #ifdef __x86_64__
 #include "i386-asm.h"
 
diff --git a/libgcc/config/i386/t-linux b/libgcc/config/i386/t-linux
index 11bb46e..8506a63 100644
--- a/libgcc/config/i386/t-linux
+++ b/libgcc/config/i386/t-linux
@@ -3,4 +3,5 @@
 # t-slibgcc-elf-ver and t-linux
 SHLIB_MAPFILES = libgcc-std.ver $(srcdir)/config/i386/libgcc-glibc.ver
 
-HOST_LIBGCC2_CFLAGS += -mlong-double-80 -DUSE_ELF_SYMVER
+HOST_LIBGCC2_CFLAGS += -mlong-double-80 -DUSE_ELF_SYMVER $(CET_FLAGS)
+CRTSTUFF_T_CFLAGS += $(CET_FLAGS)
diff --git a/libgcc/configure b/libgcc/configure
index 20169b1..38a28c2 100644
--- a/libgcc/configure
+++ b/libgcc/configure
@@ -573,6 +573,7 @@ vis_hide
 real_host_noncanonical
 accel_dir_suffix
 force_explicit_eh_registry
+CET_FLAGS
 fixed_point
 enable_decimal_float
 decimal_float
@@ -675,6 +676,7 @@ with_build_libsubdir
 enable_largefile
 enable_decimal_float
 with_system_libunwind
+enable_cet
 enable_explicit_exception_frame_registration
 with_glibc_version
 enable_tls
@@ -1314,6 +1316,8 @@ Optional Features:
 			enable decimal float extension to C.  Selecting 'bid'
 			or 'dpd' choses which decimal floating point format
 			to use
+  --enable-cet            enable Intel CET in target libraries
+                          [default=default]
   --enable-explicit-exception-frame-registration
                           register exception tables explicitly at module
                           start, for use e.g. for compatibility with
@@ -4773,6 +4777,74 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_sjlj_exceptions" >&5
 $as_echo "$ac_cv_sjlj_exceptions" >&6; }
 
+ # Check whether --enable-cet was given.
+if test "${enable_cet+set}" = set; then :
+  enableval=$enable_cet;
+      case "$enableval" in
+       yes|no|default) ;;
+       *) as_fn_error "Unknown argument to enable/disable cet" "$LINENO" 5 ;;
+                          esac
+
+else
+  enable_cet=default
+fi
+
+
+case "$host" in
+  i[34567]86-*-linux* | x86_64-*-linux*)
+    case "$enable_cet" in
+      default)
+	# Check if assembler supports CET.
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+asm ("setssbsy");
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  enable_cet=yes
+else
+  enable_cet=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+	;;
+      yes)
+	# Check if assembler supports CET.
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+asm ("setssbsy");
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+else
+  as_fn_error "assembler with CET support is required for --enable-cet" "$LINENO" 5
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+	;;
+    esac
+    ;;
+  *)
+    enable_cet=no
+    ;;
+esac
+if test x$enable_cet = xyes; then
+  CET_FLAGS="-fcf-protection -mcet"
+fi
+
+
+
 # Check whether --enable-explicit-exception-frame-registration was given.
 if test "${enable_explicit_exception_frame_registration+set}" = set; then :
   enableval=$enable_explicit_exception_frame_registration;
diff --git a/libgcc/configure.ac b/libgcc/configure.ac
index 53e7775..6e76a68 100644
--- a/libgcc/configure.ac
+++ b/libgcc/configure.ac
@@ -11,6 +11,7 @@ sinclude(../config/dfp.m4)
 sinclude(../config/unwind_ipinfo.m4)
 sinclude(../config/gthr.m4)
 sinclude(../config/sjlj.m4)
+sinclude(../config/cet.m4)
 
 AC_PREREQ(2.64)
 AC_INIT([GNU C Runtime Library], 1.0,,[libgcc])
@@ -236,6 +237,9 @@ GCC_CHECK_UNWIND_GETIPINFO
 # Check if the compiler is configured for setjmp/longjmp exceptions.
 GCC_CHECK_SJLJ_EXCEPTIONS
 
+GCC_CET_FLAGS(CET_FLAGS)
+AC_SUBST(CET_FLAGS)
+
 AC_ARG_ENABLE([explicit-exception-frame-registration],
   [AC_HELP_STRING([--enable-explicit-exception-frame-registration],
      [register exception tables explicitly at module start, for use