nptl: Add rseq registration

The rseq area is placed directly into struct pthread.  rseq
registration failure is not treated as an error, so it is possible
that threads run with inconsistent registration status.

<sys/rseq.h> is not yet installed as a public header.

Co-Authored-By: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

1 files changed, 64 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/tst-rseq.c b/sysdeps/unix/sysv/linux/tst-rseq.c
new file mode 100644
index 0000000000..926376b6a5
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-rseq.c
@@ -0,0 +1,64 @@
+/* Restartable Sequences single-threaded tests.
+   Copyright (C) 2021 Free Software Foundation, Inc.
+
+   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/>.  */
+
+/* These tests validate that rseq is registered from main in an executable
+   not linked against libpthread.  */
+
+#include <support/check.h>
+#include <stdio.h>
+#include <sys/rseq.h>
+#include <unistd.h>
+
+#ifdef RSEQ_SIG
+# include <errno.h>
+# include <error.h>
+# include <stdlib.h>
+# include <string.h>
+# include <syscall.h>
+# include "tst-rseq.h"
+
+static void
+do_rseq_main_test (void)
+{
+  TEST_VERIFY_EXIT (rseq_thread_registered ());
+}
+
+static void
+do_rseq_test (void)
+{
+  if (!rseq_available ())
+    {
+      FAIL_UNSUPPORTED ("kernel does not support rseq, skipping test");
+    }
+  do_rseq_main_test ();
+}
+#else /* RSEQ_SIG */
+static void
+do_rseq_test (void)
+{
+  FAIL_UNSUPPORTED ("glibc does not define RSEQ_SIG, skipping test");
+}
+#endif /* RSEQ_SIG */
+
+static int
+do_test (void)
+{
+  do_rseq_test ();
+  return 0;
+}
+
+#include <support/test-driver.c>