aarch64: Add GCS tests for dlopen

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

Makeconfig

@@ -633,7 +633,7 @@ link-libc-printers-tests = $(link-libc-rpath) \
 			   $(link-libc-tests-after-rpath-link)
 
 # This is how to find at build-time things that will be installed there.
-rpath-dirs = math elf dlfcn nss nis rt resolv mathvec support
+rpath-dirs = math elf dlfcn nss nis rt resolv mathvec support misc
 rpath-link = \
 $(common-objdir):$(subst $(empty) ,:,$(patsubst ../$(subdir),.,$(rpath-dirs:%=$(common-objpfx)%)))
 else  # build-static

sysdeps/unix/sysv/linux/aarch64/Makefile

@@ -8,6 +8,11 @@ ifneq (no,$(findstring no,$(have-cc-gcs) $(have-test-cc-gcs) $(have-ld-gcs)))
 
 gcs-tests-dynamic = \
   tst-gcs-disabled \
+  tst-gcs-dlopen-disabled \
+  tst-gcs-dlopen-enforced \
+  tst-gcs-dlopen-optional-off \
+  tst-gcs-dlopen-optional-on \
+  tst-gcs-dlopen-override \
   tst-gcs-enforced \
   tst-gcs-enforced-abort \
   tst-gcs-optional-off \
@@ -100,6 +105,24 @@ tst-gcs-shared-enforced-abort-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=1
 tst-gcs-shared-optional-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=2
 tst-gcs-shared-override-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=3
 
+LDFLAGS-tst-gcs-dlopen-disabled = -Wl,-z gcs=always
+LDFLAGS-tst-gcs-dlopen-enforced = -Wl,-z gcs=always
+LDFLAGS-tst-gcs-dlopen-optional-on = -Wl,-z gcs=always
+LDFLAGS-tst-gcs-dlopen-optional-off = -Wl,-z gcs=never
+LDFLAGS-tst-gcs-dlopen-override = -Wl,-z gcs=always
+
+tst-gcs-dlopen-disabled-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=0
+tst-gcs-dlopen-enforced-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=1
+tst-gcs-dlopen-optional-on-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=2
+tst-gcs-dlopen-optional-off-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=2
+tst-gcs-dlopen-override-ENV = GLIBC_TUNABLES=glibc.cpu.aarch64_gcs=3
+
+$(objpfx)tst-gcs-dlopen-disabled.out: $(objpfx)tst-gcs-mod2.so
+$(objpfx)tst-gcs-dlopen-enforced.out: $(objpfx)tst-gcs-mod2.so
+$(objpfx)tst-gcs-dlopen-optional-on.out: $(objpfx)tst-gcs-mod2.so
+$(objpfx)tst-gcs-dlopen-optional-off.out: $(objpfx)tst-gcs-mod2.so
+$(objpfx)tst-gcs-dlopen-override.out: $(objpfx)tst-gcs-mod2.so
+
 endif # ifeq ($(have-test-cc-gcs),yes)
 
 endif # ifeq ($(subdir),misc)

sysdeps/unix/sysv/linux/aarch64/tst-gcs-dlopen-disabled.c

@@ -0,0 +1,3 @@
+#define TEST_GCS_EXPECT_ENABLED 0
+#define TEST_GCS_EXPECT_DLOPEN 1
+#include "tst-gcs-dlopen.c"

sysdeps/unix/sysv/linux/aarch64/tst-gcs-dlopen-enforced.c

@@ -0,0 +1,3 @@
+#define TEST_GCS_EXPECT_ENABLED 1
+#define TEST_GCS_EXPECT_DLOPEN 0
+#include "tst-gcs-dlopen.c"

sysdeps/unix/sysv/linux/aarch64/tst-gcs-dlopen-optional-off.c

@@ -0,0 +1,3 @@
+#define TEST_GCS_EXPECT_ENABLED 0
+#define TEST_GCS_EXPECT_DLOPEN 1
+#include "tst-gcs-dlopen.c"

sysdeps/unix/sysv/linux/aarch64/tst-gcs-dlopen-optional-on.c

@@ -0,0 +1,3 @@
+#define TEST_GCS_EXPECT_ENABLED 1
+#define TEST_GCS_EXPECT_DLOPEN 0
+#include "tst-gcs-dlopen.c"

sysdeps/unix/sysv/linux/aarch64/tst-gcs-dlopen-override.c

@@ -0,0 +1,3 @@
+#define TEST_GCS_EXPECT_ENABLED 1
+#define TEST_GCS_EXPECT_DLOPEN 1
+#include "tst-gcs-dlopen.c"

sysdeps/unix/sysv/linux/aarch64/tst-gcs-dlopen.c

@@ -0,0 +1,62 @@
+/* AArch64 tests for GCS for dlopen use case.
+   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 "tst-gcs-helper.h"
+
+#include <dlfcn.h>
+#include <string.h>
+
+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;
+    }
+  /* The tst-gcs-mod2.so test library does not have GCS marking.  */
+  void *h = dlopen ("tst-gcs-mod2.so", RTLD_NOW);
+  const char *err = dlerror ();
+
+#if TEST_GCS_EXPECT_DLOPEN
+  TEST_VERIFY (h != NULL);
+#else
+  TEST_VERIFY (h == NULL);
+  /* Only accept expected GCS-related errors.  */
+  TEST_VERIFY (strstr (err, "not GCS compatible") != NULL);
+#endif
+
+#if TEST_GCS_EXPECT_ENABLED
+  TEST_VERIFY (__check_gcs_status ());
+#else
+  TEST_VERIFY (!__check_gcs_status ());
+#endif
+
+  if (h == NULL)
+    printf ("dlopen error: %s\n", err);
+  else
+    {
+      puts ("library loaded normally");
+      dlclose (h);
+    }
+
+  return 0;
+}
+
+#include <support/test-driver.c>