hurd: Implement prefer_map_32bit_exec tunable

This makes the prefer_map_32bit_exec tunable no longer Linux-specific.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20230423215526.346009-4-bugaevc@gmail.com>

5 files changed, 119 insertions, 0 deletions

diff --git a/sysdeps/x86_64/64/Makefile b/sysdeps/x86_64/64/Makefile
new file mode 100644
index 0000000000..73fcfe0bb0
--- /dev/null
+++ b/sysdeps/x86_64/64/Makefile
@@ -0,0 +1,22 @@
+ifeq ($(subdir),elf)
+
+tests-map-32bit = \
+  tst-map-32bit-1a \
+  tst-map-32bit-1b \
+# tests-map-32bit
+tst-map-32bit-1a-no-pie = yes
+tst-map-32bit-1b-no-pie = yes
+tests += $(tests-map-32bit)
+
+modules-map-32bit = \
+  tst-map-32bit-mod \
+# modules-map-32bit
+modules-names += $(modules-map-32bit)
+
+$(objpfx)tst-map-32bit-mod.so: $(libsupport)
+tst-map-32bit-1a-ENV = LD_PREFER_MAP_32BIT_EXEC=1
+$(objpfx)tst-map-32bit-1a: $(objpfx)tst-map-32bit-mod.so
+tst-map-32bit-1b-ENV = GLIBC_TUNABLES=glibc.cpu.prefer_map_32bit_exec=1
+$(objpfx)tst-map-32bit-1b: $(objpfx)tst-map-32bit-mod.so
+
+endif
diff --git a/sysdeps/x86_64/64/dl-tunables.list b/sysdeps/x86_64/64/dl-tunables.list
new file mode 100644
index 0000000000..0aab52e662
--- /dev/null
+++ b/sysdeps/x86_64/64/dl-tunables.list
@@ -0,0 +1,29 @@
+# x86-64 specific tunables.
+# 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/>.
+
+glibc {
+  cpu {
+    prefer_map_32bit_exec {
+      type: INT_32
+      minval: 0
+      maxval: 1
+      env_alias: LD_PREFER_MAP_32BIT_EXEC
+      security_level: SXID_IGNORE
+    }
+  }
+}
diff --git a/sysdeps/x86_64/64/tst-map-32bit-1a.c b/sysdeps/x86_64/64/tst-map-32bit-1a.c
new file mode 100644
index 0000000000..abc396589e
--- /dev/null
+++ b/sysdeps/x86_64/64/tst-map-32bit-1a.c
@@ -0,0 +1,34 @@
+/* Check that LD_PREFER_MAP_32BIT_EXEC works in PDE and shared library.
+   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 <stdio.h>
+#include <stdint.h>
+#include <support/check.h>
+
+extern void dso_check_map_32bit (void);
+
+static int
+do_test (void)
+{
+  printf ("do_test: %p\n", do_test);
+  TEST_VERIFY ((uintptr_t) do_test < 0xffffffffUL);
+  dso_check_map_32bit ();
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/x86_64/64/tst-map-32bit-1b.c b/sysdeps/x86_64/64/tst-map-32bit-1b.c
new file mode 100644
index 0000000000..34ab01c773
--- /dev/null
+++ b/sysdeps/x86_64/64/tst-map-32bit-1b.c
@@ -0,0 +1 @@
+#include "tst-map-32bit-1a.c"
diff --git a/sysdeps/x86_64/64/tst-map-32bit-mod.c b/sysdeps/x86_64/64/tst-map-32bit-mod.c
new file mode 100644
index 0000000000..78d4b6133c
--- /dev/null
+++ b/sysdeps/x86_64/64/tst-map-32bit-mod.c
@@ -0,0 +1,33 @@
+/* Check that LD_PREFER_MAP_32BIT_EXEC works in shared library.
+   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 <stdio.h>
+#include <stdint.h>
+#include <support/check.h>
+
+static void
+dso_do_test (void)
+{
+}
+
+void
+dso_check_map_32bit (void)
+{
+  printf ("dso_do_test: %p\n", dso_do_test);
+  TEST_VERIFY ((uintptr_t) dso_do_test < 0xffffffffUL);
+}