aarch64: Add tests for Guarded Control Stack

These tests validate that GCS tunable works as expected depending
on the GCS markings in the test binaries.

Tests validate both static and dynamically linked binaries.

These new tests are AArch64 specific. Moreover, they are included only
if linker supports the "-z gcs=<value>" option. If built, these tests
will run on systems with and without HWCAP_GCS. In the latter case the
tests will be reported as UNSUPPORTED.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

diff --git a/sysdeps/unix/sysv/linux/aarch64/Makefile b/sysdeps/unix/sysv/linux/aarch64/Makefile
index 1fdad67fae18935fa44b8a50fdc60c3cdedd5580..e16799fedd325f51db8a56389fe24b11d44f8ec9 100644 (file)
--- a/sysdeps/unix/sysv/linux/aarch64/Makefile
+++ b/sysdeps/unix/sysv/linux/aarch64/Makefile
@@ -3,7 +3,77 @@ sysdep_headers += sys/elf.h
 tests += \
   tst-aarch64-pkey \
   # tests
-endif
+
+ifneq (no,$(findstring no,$(have-cc-gcs) $(have-test-cc-gcs) $(have-ld-gcs)))
+
+gcs-tests-dynamic = \
+  tst-gcs-disabled \
+  tst-gcs-enforced \
+  tst-gcs-enforced-abort \
+  tst-gcs-optional-off \
+  tst-gcs-optional-on \
+  tst-gcs-override \
+  # gcs-tests-dynamic
+
+gcs-tests-static = \
+  tst-gcs-disabled-static \
+  tst-gcs-enforced-static \
+  tst-gcs-enforced-static-abort \
+  tst-gcs-optional-static-off \
+  tst-gcs-optional-static-on \
+  tst-gcs-override-static \
+  # gcs-tests-static
+
+tests += \
+  $(gcs-tests-dynamic) \
+  $(gcs-tests-static) \
+  # tests
+
+tests-static += \
+  $(gcs-tests-static) \
+  # tests-static
+
+define run-gcs-abort-test
+  $(test-wrapper-env) $(run-program-env) \
+  $(tst-gcs-$*-abort-ENV) $(host-test-program-cmd)
+endef
+
+$(objpfx)tst-gcs-%-abort.out: $(..)sysdeps/unix/sysv/linux/aarch64/tst-gcs-abort.sh \
+       $(objpfx)tst-gcs-%-abort
+       $(SHELL) $< $(common-objpfx) $(test-name) '$(run-gcs-abort-test)'; \
+       $(evaluate-test)
+
+LDFLAGS-tst-gcs-disabled += -Wl,-z gcs=always
+LDFLAGS-tst-gcs-enforced += -Wl,-z gcs=always
+LDFLAGS-tst-gcs-enforced-abort += -Wl,-z gcs=never
+LDFLAGS-tst-gcs-optional-on += -Wl,-z gcs=always
+LDFLAGS-tst-gcs-optional-off += -Wl,-z gcs=never
+LDFLAGS-tst-gcs-override += -Wl,-z gcs=never
+
+LDFLAGS-tst-gcs-disabled-static += -Wl,-z gcs=always
+LDFLAGS-tst-gcs-enforced-static += -Wl,-z gcs=always
+LDFLAGS-tst-gcs-enforced-static-abort += -Wl,-z gcs=never
+LDFLAGS-tst-gcs-optional-static-on += -Wl,-z gcs=always
+LDFLAGS-tst-gcs-optional-static-off += -Wl,-z gcs=never
+LDFLAGS-tst-gcs-override-static += -Wl,-z gcs=never
+
+tst-gcs-disabled-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=0
+tst-gcs-enforced-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=1
+tst-gcs-enforced-abort-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=1
+tst-gcs-optional-on-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=2
+tst-gcs-optional-off-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=2
+tst-gcs-override-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=3
+
+tst-gcs-disabled-static-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=0
+tst-gcs-enforced-static-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=1
+tst-gcs-enforced-static-abort-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=1
+tst-gcs-optional-static-on-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=2
+tst-gcs-optional-static-off-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=2
+tst-gcs-override-static-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=3
+
+endif # ifeq ($(have-test-cc-gcs),yes)
+
+endif # ifeq ($(subdir),misc)
 
 ifeq ($(subdir),stdlib)
 gen-as-const-headers += ucontext_i.sym

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-abort.sh b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-abort.sh
new file mode 100644 (file)
index 0000000..9e2be2d
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-abort.sh
@@ -0,0 +1,39 @@
+#!/bin/sh
+# Test wrapper for AArch64 tests for GCS that are expected to abort.
+# Copyright (C) 2025 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/>.
+
+objpfx=$1; shift
+tstname=$1; shift
+tstrun=$1; shift
+
+logfile=$objpfx/$tstname.out
+
+rm -vf $logfile
+touch $logfile
+
+${tstrun} 2>> $logfile >> $logfile; status=$?
+
+if test $status -eq 127 \
+  && grep -q -w "not GCS compatible" "$logfile" ; then
+  exit 0
+elif test $status -eq 77; then
+  exit 77
+else
+  echo "unexpected test output or exit status $status"
+  exit 1
+fi

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled-static.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled-static.c
new file mode 100644 (file)
index 0000000..c71d68c
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled-static.c
@@ -0,0 +1 @@
+#include "tst-gcs-disabled.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled.c
new file mode 100644 (file)
index 0000000..bd68878
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-disabled.c
@@ -0,0 +1,2 @@
+#define TEST_GCS_EXPECT_ENABLED 0
+#include "tst-gcs-skeleton.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-abort.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-abort.c
new file mode 100644 (file)
index 0000000..608318f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-abort.c
@@ -0,0 +1,2 @@
+#define TEST_GCS_EXPECT_ENABLED 1
+#include "tst-gcs-skeleton.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static-abort.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static-abort.c
new file mode 100644 (file)
index 0000000..c20a999
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static-abort.c
@@ -0,0 +1 @@
+#include "tst-gcs-enforced-abort.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static.c
new file mode 100644 (file)
index 0000000..bb39dad
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced-static.c
@@ -0,0 +1 @@
+#include "tst-gcs-enforced.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced.c
new file mode 100644 (file)
index 0000000..608318f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-enforced.c
@@ -0,0 +1,2 @@
+#define TEST_GCS_EXPECT_ENABLED 1
+#include "tst-gcs-skeleton.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-off.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-off.c
new file mode 100644 (file)
index 0000000..bd68878
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-off.c
@@ -0,0 +1,2 @@
+#define TEST_GCS_EXPECT_ENABLED 0
+#include "tst-gcs-skeleton.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-on.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-on.c
new file mode 100644 (file)
index 0000000..608318f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-on.c
@@ -0,0 +1,2 @@
+#define TEST_GCS_EXPECT_ENABLED 1
+#include "tst-gcs-skeleton.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-off.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-off.c
new file mode 100644 (file)
index 0000000..54e3b9a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-off.c
@@ -0,0 +1 @@
+#include "tst-gcs-optional-off.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-on.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-on.c
new file mode 100644 (file)
index 0000000..11b884b
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-optional-static-on.c
@@ -0,0 +1 @@
+#include "tst-gcs-optional-on.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override-static.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override-static.c
new file mode 100644 (file)
index 0000000..09055dc
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override-static.c
@@ -0,0 +1 @@
+#include "tst-gcs-override.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override.c
new file mode 100644 (file)
index 0000000..608318f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-override.c
@@ -0,0 +1,2 @@
+#define TEST_GCS_EXPECT_ENABLED 1
+#include "tst-gcs-skeleton.c"

diff --git a/sysdeps/unix/sysv/linux/aarch64/tst-gcs-skeleton.c b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-skeleton.c
new file mode 100644 (file)
index 0000000..37692c9
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/aarch64/tst-gcs-skeleton.c
@@ -0,0 +1,58 @@
+/* AArch64 tests for GCS.
+   Copyright (C) 2025 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 <support/check.h>
+#include <support/support.h>
+#include <support/test-driver.h>
+
+#include <stdio.h>
+#include <sys/auxv.h>
+
+static bool __check_gcs_status (void)
+{
+  register unsigned long x16 asm ("x16");
+  asm volatile (
+    "mov       x16, #1 /* _CHKFEAT_GCS */\n"
+    "hint      40 /* CHKFEAT_X16 */\n"
+    : "=r" (x16));
+  return x16 ^ 1;
+}
+
+static int
+do_test (void)
+{
+  /* Check if GCS could possible by enabled.  */
+  if (!(getauxval (AT_HWCAP) & HWCAP_GCS))
+    {
+      puts ("kernel or CPU does not support GCS");
+      return EXIT_UNSUPPORTED;
+    }
+  bool gcs_enabled = __check_gcs_status ();
+  if (gcs_enabled)
+    puts ("GCS enabled");
+  else
+    puts ("GCS not enabled");
+#if TEST_GCS_EXPECT_ENABLED
+  TEST_VERIFY (gcs_enabled);
+#else
+  TEST_VERIFY (!gcs_enabled);
+#endif
+  return 0;
+}
+
+#include <support/test-driver.c>