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, 52 insertions, 0 deletions

diff --git a/elf/tst-gnu2-tls1.c b/elf/tst-gnu2-tls1.c
new file mode 100644
index 0000000000..f55de59fc7
--- /dev/null
+++ b/elf/tst-gnu2-tls1.c
@@ -0,0 +1,52 @@
+/* Test local and global dynamic models for GNU2 TLS.
+   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/>.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+extern int * get_gd (void);
+extern void set_gd (int);
+extern int test_gd (int);
+extern int * get_ld (void);
+extern void set_ld (int);
+extern int test_ld (int);
+
+__thread int gd = 1;
+
+static int
+do_test (void)
+{
+  int *p;
+
+  p = get_gd ();
+  set_gd (3);
+  if (*p != 3 || !test_gd (3))
+    abort ();
+
+  p = get_ld ();
+  set_ld (4);
+  if (*p != 4 || !test_ld (4))
+    abort ();
+
+  printf ("PASS\n");
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"