x86-64: Properly align stack in _dl_tlsdesc_dynamic [BZ #20309]

Since _dl_tlsdesc_dynamic is called via PLT, we need to add 8 bytes for
push in the PLT entry to align the stack.

	[BZ #20309]
	* configure.ac (have-mtls-dialect-gnu2): Set to yes if
	-mtls-dialect=gnu2 works.
	* configure: Regenerated.
	* elf/Makefile [have-mtls-dialect-gnu2 = yes]
	(tests): Add tst-gnu2-tls1.
	(modules-names): Add tst-gnu2-tls1mod.
	($(objpfx)tst-gnu2-tls1): New.
	(tst-gnu2-tls1mod.so-no-z-defs): Likewise.
	(CFLAGS-tst-gnu2-tls1mod.c): Likewise.
	* elf/tst-gnu2-tls1.c: New file.
	* elf/tst-gnu2-tls1mod.c: Likewise.
	* sysdeps/x86_64/dl-tlsdesc.S (_dl_tlsdesc_dynamic): Add 8
	bytes for push in the PLT entry to align the stack.

1 files changed, 56 insertions, 0 deletions

diff --git a/elf/tst-gnu2-tls1mod.c b/elf/tst-gnu2-tls1mod.c
new file mode 100644
index 0000000000..45c48164b2
--- /dev/null
+++ b/elf/tst-gnu2-tls1mod.c
@@ -0,0 +1,56 @@
+/* DSO used by tst-gnu2-tls1.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+static __thread int ld;
+
+int *
+get_ld (void)
+{
+  return &ld;
+}
+
+void
+set_ld (int i)
+{
+  ld = i;
+}
+
+int
+test_ld (int i)
+{
+  return ld == i;
+}
+extern __thread int gd;
+
+int *
+get_gd (void)
+{
+  return &gd;
+}
+
+void
+set_gd (int i)
+{
+  gd = i;
+}
+
+int
+test_gd (int i)
+{
+  return gd == i;
+}