[RFC,4/4] rseq registration tests

diff --git a/nptl/Makefile b/nptl/Makefile
index 3a5dc80c65..797309f7a8 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -323,7 +323,7 @@  tests = tst-attr1 tst-attr2 tst-attr3 tst-default-attr \
 tests-internal := tst-rwlock19 tst-rwlock20 \
 		  tst-sem11 tst-sem12 tst-sem13 \
 		  tst-barrier5 tst-signal7 tst-mutex8 tst-mutex8-static \
-		  tst-mutexpi8 tst-mutexpi8-static
+		  tst-mutexpi8 tst-mutexpi8-static tst-rseq
 
 xtests = tst-setuid1 tst-setuid1-static tst-setuid2 \
 	tst-mutexpp1 tst-mutexpp6 tst-mutexpp10
diff --git a/nptl/tst-rseq.c b/nptl/tst-rseq.c
new file mode 100644
index 0000000000..218acbee51
--- /dev/null
+++ b/nptl/tst-rseq.c
@@ -0,0 +1,384 @@ 
+/* Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, 2018.
+
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+/* These tests validate that rseq is registered from various execution
+   contexts (main thread, constructor, destructor, other threads, other
+   threads created from constructor and destructor, forked process
+   (without exec), pthread_atfork handlers, pthread setspecific
+   destructors, C++ thread and process destructors, signal handlers,
+   atexit handlers).
+
+   See the Linux kernel selftests for extensive rseq stress-tests.  */
+
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <support/check.h>
+
+#if defined (__linux__) && defined (__NR_rseq)
+#define HAS_RSEQ
+#endif
+
+#ifdef HAS_RSEQ
+#include <linux/rseq.h>
+#include <pthread.h>
+#include <syscall.h>
+#include <stdlib.h>
+#include <error.h>
+#include <errno.h>
+#include <string.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <atomic.h>
+
+static pthread_key_t rseq_test_key;
+
+extern __thread volatile struct rseq __rseq_abi
+__attribute__ ((tls_model ("initial-exec")));
+
+static int
+rseq_thread_registered (void)
+{
+  return __rseq_abi.cpu_id >= 0;
+}
+
+static int
+do_rseq_main_test (void)
+{
+  if (raise (SIGUSR1))
+    FAIL_EXIT1 ("error raising signal");
+  if (pthread_setspecific (rseq_test_key, (void *) 1l))
+    FAIL_EXIT1 ("error in pthread_setspecific");
+  if (!rseq_thread_registered ())
+    {
+      FAIL_RET ("rseq not registered in main thread");
+    }
+  return 0;
+}
+
+static void
+cancel_routine (void *arg)
+{
+  if (!rseq_thread_registered ())
+    {
+      printf ("rseq not registered in cancel routine\n");
+      support_record_failure ();
+    }
+}
+
+static int cancel_thread_ready;
+
+static void
+test_cancel_thread (void)
+{
+  pthread_cleanup_push (cancel_routine, NULL);
+  atomic_store_release (&cancel_thread_ready, 1);
+  for (;;)
+    usleep (100);
+  pthread_cleanup_pop (0);
+}
+
+static void *
+thread_function (void * arg)
+{
+  int i = (int) (intptr_t) arg;
+
+  if (raise (SIGUSR1))
+    FAIL_EXIT1 ("error raising signal");
+  if (i == 0)
+    test_cancel_thread ();
+  if (pthread_setspecific (rseq_test_key, (void *) 1l))
+    FAIL_EXIT1 ("error in pthread_setspecific");
+  return rseq_thread_registered () ? NULL : (void *) 1l;
+}
+
+static void
+sighandler (int sig)
+{
+  if (!rseq_thread_registered ())
+    {
+      printf ("rseq not registered in signal handler\n");
+      support_record_failure ();
+    }
+}
+
+static void
+setup_signals (void)
+{
+  struct sigaction sa;
+
+  sigemptyset (&sa.sa_mask);
+  sigaddset (&sa.sa_mask, SIGUSR1);
+  sa.sa_flags = 0;
+  sa.sa_handler = sighandler;
+  if (sigaction (SIGUSR1, &sa, NULL) != 0)
+    {
+      FAIL_EXIT1 ("sigaction failure: %s", strerror (errno));
+    }
+}
+
+#define N 7
+static const int t[N] = { 1, 2, 6, 5, 4, 3, 50 };
+
+static int
+do_rseq_threads_test (int nr_threads)
+{
+  pthread_t th[nr_threads];
+  int i;
+  int result = 0;
+  pthread_attr_t at;
+
+  if (pthread_attr_init (&at) != 0)
+    {
+      FAIL_EXIT1 ("attr_init failed");
+    }
+
+  if (pthread_attr_setstacksize (&at, 1 * 1024 * 1024) != 0)
+    {
+      FAIL_EXIT1 ("attr_setstacksize failed");
+    }
+
+  cancel_thread_ready = 0;
+  for (i = 0; i < nr_threads; ++i)
+    if (pthread_create (&th[i], NULL, thread_function,
+                        (void *) (intptr_t) i) != 0)
+      {
+        FAIL_EXIT1 ("creation of thread %d failed", i);
+      }
+
+  if (pthread_attr_destroy (&at) != 0)
+    {
+      FAIL_EXIT1 ("attr_destroy failed");
+    }
+
+  while (!atomic_load_acquire (&cancel_thread_ready))
+    usleep (100);
+
+  if (pthread_cancel (th[0]))
+    FAIL_EXIT1 ("error in pthread_cancel");
+
+  for (i = 0; i < nr_threads; ++i)
+    {
+      void *v;
+      if (pthread_join (th[i], &v) != 0)
+        {
+          printf ("join of thread %d failed\n", i);
+          result = 1;
+        }
+      else if (i != 0 && v != NULL)
+        {
+          printf ("join %d successful, but child failed\n", i);
+          result = 1;
+        }
+      else if (i == 0 && v == NULL)
+        {
+          printf ("join %d successful, child did not fail as expected\n", i);
+          result = 1;
+        }
+    }
+  return result;
+}
+
+static int
+sys_rseq (volatile struct rseq *rseq_abi, uint32_t rseq_len,
+          int flags, uint32_t sig)
+{
+  return syscall (__NR_rseq, rseq_abi, rseq_len, flags, sig);
+}
+
+static int
+rseq_available (void)
+{
+  int rc;
+
+  rc = sys_rseq (NULL, 0, 0, 0);
+  if (rc != -1)
+    FAIL_EXIT1 ("Unexpected rseq return value %d", rc);
+  switch (errno)
+    {
+    case ENOSYS:
+      return 0;
+    case EINVAL:
+      return 1;
+    default:
+      FAIL_EXIT1 ("Unexpected rseq error %s", strerror (errno));
+    }
+}
+
+static int
+do_rseq_fork_test (void)
+{
+  int status;
+  pid_t pid, retpid;
+
+  pid = fork ();
+  switch (pid)
+    {
+      case 0:
+        exit (do_rseq_main_test ());
+      case -1:
+        FAIL_EXIT1 ("Unexpected fork error %s", strerror (errno));
+    }
+  retpid = TEMP_FAILURE_RETRY (waitpid (pid, &status, 0));
+  if (retpid != pid)
+    {
+      FAIL_EXIT1 ("waitpid returned %ld, expected %ld",
+                  (long int) retpid, (long int) pid);
+    }
+  if (WEXITSTATUS (status))
+    {
+      printf ("rseq not registered in child\n");
+      return 1;
+    }
+  return 0;
+}
+
+static int
+do_rseq_test (void)
+{
+  int i, result = 0;
+
+  if (!rseq_available ())
+    {
+      FAIL_UNSUPPORTED ("kernel does not support rseq, skipping test");
+    }
+  setup_signals ();
+  if (raise (SIGUSR1))
+    FAIL_EXIT1 ("error raising signal");
+  if (do_rseq_main_test ())
+    result = 1;
+  for (i = 0; i < N; i++)
+    {
+      if (do_rseq_threads_test (t[i]))
+        result = 1;
+    }
+  if (do_rseq_fork_test ())
+    result = 1;
+  return result;
+}
+
+static void
+atfork_prepare (void)
+{
+  if (!rseq_thread_registered ())
+    {
+      printf ("rseq not registered in pthread atfork prepare\n");
+      support_record_failure ();
+    }
+}
+
+static void
+atfork_parent (void)
+{
+  if (!rseq_thread_registered ())
+    {
+      printf ("rseq not registered in pthread atfork parent\n");
+      support_record_failure ();
+    }
+}
+
+static void
+atfork_child (void)
+{
+  if (!rseq_thread_registered ())
+    {
+      printf ("rseq not registered in pthread atfork child\n");
+      support_record_failure ();
+    }
+}
+
+static void
+rseq_key_destructor (void *arg)
+{
+  /* Cannot use deferred failure reporting after main () returns.  */
+  if (!rseq_thread_registered ())
+    FAIL_EXIT1 ("rseq not registered in pthread key destructor");
+}
+
+static void
+do_rseq_create_key (void)
+{
+  if (pthread_key_create (&rseq_test_key, rseq_key_destructor))
+    FAIL_EXIT1 ("error in pthread_key_create");
+}
+
+static void
+do_rseq_delete_key (void)
+{
+  if (pthread_key_delete (rseq_test_key))
+    FAIL_EXIT1 ("error in pthread_key_delete");
+}
+
+static void
+atexit_handler (void)
+{
+  /* Cannot use deferred failure reporting after main () returns.  */
+  if (!rseq_thread_registered ())
+    FAIL_EXIT1 ("rseq not registered in atexit handler");
+}
+
+static void __attribute__ ((constructor))
+do_rseq_constructor_test (void)
+{
+  support_record_failure_init ();
+  if (atexit (atexit_handler))
+    {
+      FAIL_EXIT1 ("error calling atexit");
+    }
+  do_rseq_create_key ();
+  if (pthread_atfork (atfork_prepare, atfork_parent, atfork_child))
+    FAIL_EXIT1 ("error calling pthread_atfork");
+  if (do_rseq_test ())
+    FAIL_EXIT1 ("rseq not registered within constructor");
+}
+
+static void __attribute__ ((destructor))
+do_rseq_destructor_test (void)
+{
+  /* Cannot use deferred failure reporting after main () returns.  */
+  if (do_rseq_test ())
+    FAIL_EXIT1 ("rseq not registered within destructor");
+  do_rseq_delete_key ();
+}
+
+/* Test C++ destructor called at thread and process exit.  */
+void
+__call_tls_dtors (void)
+{
+  /* Cannot use deferred failure reporting after main () returns.  */
+  if (!rseq_thread_registered ())
+    FAIL_EXIT1 ("rseq not registered in C++ thread/process exit destructor");
+}
+#else
+static int
+do_rseq_test (void)
+{
+  FAIL_UNSUPPORTED ("kernel headers do not support rseq, skipping test");
+  return 0;
+}
+#endif
+
+static int
+do_test (void)
+{
+  return do_rseq_test ();
+}
+
+#include <support/test-driver.c>