[glibc] x86/cet: Add tests for GLIBC_TUNABLES=glibc.cpu.hwcaps=-SHSTK

[glibc] x86/cet: Add tests for GLIBC_TUNABLES=glibc.cpu.hwcaps=-SHSTK

[H.J. Lu]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=9424ce80c2a08f4dfc06d5442b770ed5ec798c4b

commit 9424ce80c2a08f4dfc06d5442b770ed5ec798c4b
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Mar 17 16:21:49 2023 -0700

    x86/cet: Add tests for GLIBC_TUNABLES=glibc.cpu.hwcaps=-SHSTK
    
    Verify that GLIBC_TUNABLES=glibc.cpu.hwcaps=-SHSTK turns off shadow
    stack properly.

Diff:
---
 sysdeps/x86/Makefile                     |  7 +++++++
 sysdeps/x86/tst-shstk-legacy-1c-static.c |  1 +
 sysdeps/x86/tst-shstk-legacy-1c.c        | 20 ++++++++++++++++++++
 3 files changed, 28 insertions(+)

diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
index 23f3ac1430..b857ad6ea6 100644
--- a/sysdeps/x86/Makefile
+++ b/sysdeps/x86/Makefile
@@ -171,10 +171,13 @@ tests += \
   tst-shstk-legacy-1a-static \
   tst-shstk-legacy-1b \
   tst-shstk-legacy-1b-static \
+  tst-shstk-legacy-1c \
+  tst-shstk-legacy-1c-static \
 # tests
 tests-static += \
   tst-shstk-legacy-1a-static \
   tst-shstk-legacy-1b-static \
+  tst-shstk-legacy-1c-static \
 # tests-static
 extra-objs += \
   tst-shstk-legacy-1-extra.o \
@@ -272,6 +275,10 @@ $(objpfx)tst-shstk-legacy-1a: $(objpfx)tst-shstk-legacy-1-extra.o
 $(objpfx)tst-shstk-legacy-1a-static: $(objpfx)tst-shstk-legacy-1-extra.o
 $(objpfx)tst-shstk-legacy-1b: $(objpfx)tst-shstk-legacy-1-extra.o
 $(objpfx)tst-shstk-legacy-1b-static: $(objpfx)tst-shstk-legacy-1-extra.o
+tst-shstk-legacy-1c-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-SHSTK
+tst-shstk-legacy-1c-static-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-SHSTK
+$(objpfx)tst-shstk-legacy-1c: $(objpfx)tst-shstk-legacy-1-extra.o
+$(objpfx)tst-shstk-legacy-1c-static: $(objpfx)tst-shstk-legacy-1-extra.o
 endif
 
 # Add -fcf-protection to CFLAGS when CET is enabled.
diff --git a/sysdeps/x86/tst-shstk-legacy-1c-static.c b/sysdeps/x86/tst-shstk-legacy-1c-static.c
new file mode 100644
index 0000000000..91ea346aaf
--- /dev/null
+++ b/sysdeps/x86/tst-shstk-legacy-1c-static.c
@@ -0,0 +1 @@
+#include "tst-shstk-legacy-1c.c"
diff --git a/sysdeps/x86/tst-shstk-legacy-1c.c b/sysdeps/x86/tst-shstk-legacy-1c.c
new file mode 100644
index 0000000000..eb218c6c70
--- /dev/null
+++ b/sysdeps/x86/tst-shstk-legacy-1c.c
@@ -0,0 +1,20 @@
+/* Check that legacy shadow stack code won't trigger segfault with
+   GLIBC_TUNABLES=glibc.cpu.hwcaps=-SHSTK
+   Copyright (C) 2023 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include "tst-shstk-legacy-1a.c"