nptl: Add C11 threads mtx_* functions

This patch adds the mtx_* definitions from C11 threads (ISO/IEC 9899:2011),
more specifically mtx_init, mtx_destroy, mtx_lock, mtx_timedlock, mtx_trylock,
mtx_unlock, and required types.

Mostly of the definitions are composed based on POSIX conterparts, and mtx_t
is also based on internal pthread fields, but with a distinct internal layout
to avoid possible issues with code interchange (such as trying to pass POSIX
structure on C11 functions and to avoid inclusion of pthread.h).  The idea
is to make possible to share POSIX internal implementations for mostly of
the code (and making adjustment only when required).

Checked with a build for all major ABI (aarch64-linux-gnu, alpha-linux-gnu,
arm-linux-gnueabi, i386-linux-gnu, ia64-linux-gnu, m68k-linux-gnu,
microblaze-linux-gnu [1], mips{64}-linux-gnu, nios2-linux-gnu,
powerpc{64le}-linux-gnu, s390{x}-linux-gnu, sparc{64}-linux-gnu,
and x86_64-linux-gnu).

Also ran a full check on aarch64-linux-gnu, x86_64-linux-gnu, i686-linux-gnu,
arm-linux-gnueabhf, and powerpc64le-linux-gnu.

	[BZ #14092]
	* conform/data/threads.h-data (mtx_plain): New constant.
	(mtx_recursive): Likewise.
	(mtx_timed): Likewise.
	(mtx_t): New type.
	(mtx_init): New function.
	(mtx_lock): Likewise.
	(mtx_timedlock): Likewise.
	(mtx_trylock): Likewise.
	(mtx_unlock): Likewise.
	(mtx_destroy): Likewise.
	* nptl/Makefile (libpthread-routines): Add mtx_destroy, mtx_init,
	mtx_lock, mtx_timedlock, mtx_trylock, and mtx_unlock object.
	* nptl/Versions (libpthread) [GLIBC_2.28]): Add mtx_init, mtx_lock,
	mtx_timedlock, mtx_trylock, mtx_unlock, and mtx_destroy.
	* nptl/mtx_destroy.c: New file.
	* nptl/mtx_init.c: Likewise.
	* nptl/mtx_lock.c: Likewise.
	* nptl/mtx_timedlock.c: Likewise.
	* nptl/mtx_trylock.c: Likewise.
	* nptl/mtx_unlock.c: Likewise.
	* sysdeps/nptl/threads.h (mtx_plain): New enumeration.
	(mtx_recursive): Likewise.
	(mtx_timed): Likewise.
	(mtx_t): New type.
	(mtx_init): New prototype.
	(mtx_lock): Likewise.
	(mtx_timedlock): Likewise.
	(mtx_trylock): Likewise.
	(mtx_unlock): Likewise.
	(mtx_destroy): Likewise.

ChangeLog

@@ -1,5 +1,37 @@
 2018-07-24  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
+	[BZ #14092]
+	* conform/data/threads.h-data (mtx_plain): New constant.
+	(mtx_recursive): Likewise.
+	(mtx_timed): Likewise.
+	(mtx_t): New type.
+	(mtx_init): New function.
+	(mtx_lock): Likewise.
+	(mtx_timedlock): Likewise.
+	(mtx_trylock): Likewise.
+	(mtx_unlock): Likewise.
+	(mtx_destroy): Likewise.
+	* nptl/Makefile (libpthread-routines): Add mtx_destroy, mtx_init,
+	mtx_lock, mtx_timedlock, mtx_trylock, and mtx_unlock object.
+	* nptl/Versions (libpthread) [GLIBC_2.28]): Add mtx_init, mtx_lock,
+	mtx_timedlock, mtx_trylock, mtx_unlock, and mtx_destroy.
+	* nptl/mtx_destroy.c: New file.
+	* nptl/mtx_init.c: Likewise.
+	* nptl/mtx_lock.c: Likewise.
+	* nptl/mtx_timedlock.c: Likewise.
+	* nptl/mtx_trylock.c: Likewise.
+	* nptl/mtx_unlock.c: Likewise.
+	* sysdeps/nptl/threads.h (mtx_plain): New enumeration.
+	(mtx_recursive): Likewise.
+	(mtx_timed): Likewise.
+	(mtx_t): New type.
+	(mtx_init): New prototype.
+	(mtx_lock): Likewise.
+	(mtx_timedlock): Likewise.
+	(mtx_trylock): Likewise.
+	(mtx_unlock): Likewise.
+	(mtx_destroy): Likewise.
+
 	[BZ #14092]
 	* conform/Makefile (conformtest-headers-ISO11): Add threads.h.
 	(linknamespace-libs-ISO11): Add libpthread.a.

conform/data/threads.h-data

@@ -6,8 +6,13 @@ constant thrd_error
 constant thrd_nomem
 constant thrd_timedout
 
+constant mtx_plain
+constant mtx_recursive
+constant mtx_timed
+
 type thrd_t
 type thrd_start_t
+type mtx_t
 
 function int thrd_create (thrd_t*, thrd_start_t, void*)
 function int thrd_equal (thrd_t, thrd_t)
@@ -18,6 +23,13 @@ function int thrd_detach (thrd_t)
 function int thrd_join (thrd_t, int*)
 function void thrd_yield (void)
 
+function int mtx_init (mtx_t*, int)
+function int mtx_lock (mtx_t*)
+function int mtx_timedlock (mtx_t*, const struct timespec*)
+function int mtx_trylock (mtx_t*)
+function int mtx_unlock (mtx_t*)
+function void mtx_destroy (mtx_t*)
+
 #include "time.h-data"
 
 #endif

nptl/Makefile

@@ -141,7 +141,9 @@ libpthread-routines = nptl-init nptlfreeres vars events version pt-interp \
 		      pthread_mutex_setprioceiling \
 		      pthread_setname pthread_getname \
 		      pthread_setattr_default_np pthread_getattr_default_np \
-		      thrd_create thrd_detach thrd_exit thrd_join
+		      thrd_create thrd_detach thrd_exit thrd_join \
+		      mtx_destroy mtx_init mtx_lock mtx_timedlock \
+		      mtx_trylock mtx_unlock
 #		      pthread_setuid pthread_seteuid pthread_setreuid \
 #		      pthread_setresuid \
 #		      pthread_setgid pthread_setegid pthread_setregid \

nptl/Versions

@@ -272,6 +272,7 @@ libpthread {
   # C11 thread symbols.
   GLIBC_2.28 {
     thrd_create; thrd_detach; thrd_exit; thrd_join;
+    mtx_init; mtx_lock; mtx_timedlock; mtx_trylock; mtx_unlock; mtx_destroy;
   }
 
   GLIBC_PRIVATE {

nptl/mtx_destroy.c

@@ -0,0 +1,26 @@
+/* C11 threads mutex destroy implementation.
+   Copyright (C) 2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include "thrd_priv.h"
+#include "pthreadP.h"
+
+void
+mtx_destroy (mtx_t *mutex)
+{
+  __pthread_mutex_destroy ((pthread_mutex_t *) mutex);
+}

nptl/mtx_init.c

@@ -0,0 +1,53 @@
+/* C11 threads mutex initialization implementation.
+   Copyright (C) 2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdalign.h>
+
+#include "thrd_priv.h"
+
+int
+mtx_init (mtx_t *mutex, int type)
+{
+  _Static_assert (sizeof (mtx_t) == sizeof (pthread_mutex_t),
+		  "sizeof (mtx_t) != sizeof (pthread_mutex_t)");
+  _Static_assert (alignof (mtx_t) == alignof (pthread_mutex_t),
+		  "alignof (mtx_t) != alignof (pthread_mutex_t)");
+
+  pthread_mutexattr_t attr;
+
+  __pthread_mutexattr_init (&attr);
+
+  /* Another possible solution would be to set the flags directly in
+     mutex object. */
+  switch (type)
+  {
+    case mtx_plain | mtx_recursive:
+    case mtx_timed | mtx_recursive:
+      __pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
+      break;
+    case mtx_plain:
+    case mtx_timed: /* No difference between both in standard */
+    default:
+      __pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_NORMAL);
+      break;
+  }
+
+  int err_code = __pthread_mutex_init ((pthread_mutex_t *) mutex, &attr);
+  /* pthread_mutexattr_destroy implementation is a noop.  */
+  return thrd_err_map (err_code);
+}

nptl/mtx_lock.c

@@ -0,0 +1,26 @@
+/* C11 threads mutex lock implementation.
+   Copyright (C) 2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include "thrd_priv.h"
+
+int
+mtx_lock (mtx_t *mutex)
+{
+  int err_code = __pthread_mutex_lock ((pthread_mutex_t *) mutex);
+  return thrd_err_map (err_code);
+}

nptl/mtx_timedlock.c

@@ -0,0 +1,28 @@
+/* C11 threads mutex timed lock implementation.
+   Copyright (C) 2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include "thrd_priv.h"
+
+int
+mtx_timedlock (mtx_t *restrict mutex,
+	       const struct timespec *restrict time_point)
+{
+  int err_code = __pthread_mutex_timedlock ((pthread_mutex_t *)mutex,
+					    time_point);
+  return thrd_err_map (err_code);
+}

nptl/mtx_trylock.c

@@ -0,0 +1,26 @@
+/* C11 threads mutex try lock implementation.
+   Copyright (C) 2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include "thrd_priv.h"
+
+int
+mtx_trylock (mtx_t *mutex)
+{
+  int err_code = __pthread_mutex_trylock ((pthread_mutex_t *) mutex);
+  return thrd_err_map (err_code);
+}

nptl/mtx_unlock.c

@@ -0,0 +1,26 @@
+/* C11 threads mutex unlock implementation.
+   Copyright (C) 2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include "thrd_priv.h"
+
+int
+mtx_unlock (mtx_t *mutex)
+{
+  int err_code = __pthread_mutex_unlock ((pthread_mutex_t *) mutex);
+  return thrd_err_map (err_code);
+}

nptl/threads.h

@@ -24,6 +24,7 @@
 
 __BEGIN_DECLS
 
+#include <bits/pthreadtypes-arch.h>
 #include <bits/types/struct_timespec.h>
 
 typedef unsigned long int thrd_t;
@@ -39,6 +40,20 @@ enum
   thrd_timedout = 4
 };
 
+/* Mutex types.  */
+enum
+{
+  mtx_plain     = 0,
+  mtx_recursive = 1,
+  mtx_timed     = 2
+};
+
+typedef union
+{
+  char __size[__SIZEOF_PTHREAD_MUTEX_T];
+  long int __align __LOCK_ALIGNMENT;
+} mtx_t;
+
 /* Threads functions.  */
 
 /* Create a new thread executing the function __FUNC.  Arguments for __FUNC
@@ -85,6 +100,35 @@ thrd_equal (thrd_t __thread1, thrd_t __thread2)
 }
 #endif
 
+
+/* Mutex functions.  */
+
+/* Creates a new mutex object with type __TYPE.  If successful the new
+   object is pointed by __MUTEX.  */
+extern int mtx_init (mtx_t *__mutex, int __type);
+
+/* Block the current thread until the mutex pointed to by __MUTEX is
+   unlocked.  In that case current thread will not be blocked.  */
+extern int mtx_lock (mtx_t *__mutex);
+
+/* Block the current thread until the mutex pointed by __MUTEX is unlocked
+   or time pointed by __TIME_POINT is reached.  In case the mutex is unlock,
+   the current thread will not be blocked.  */
+extern int mtx_timedlock (mtx_t *__restrict __mutex,
+			  const struct timespec *__restrict __time_point);
+
+/* Try to lock the mutex pointed by __MUTEX without blocking.  If the mutex
+   is free the current threads takes control of it, otherwise it returns
+   immediately.  */
+extern int mtx_trylock (mtx_t *__mutex);
+
+/* Unlock the mutex pointed by __MUTEX.  It may potentially awake other
+   threads waiting on this mutex.  */
+extern int mtx_unlock (mtx_t *__mutex);
+
+/* Destroy the mutex object pointed by __MUTEX.  */
+extern void mtx_destroy (mtx_t *__mutex);
+
 __END_DECLS
 
 #endif /* _THREADS_H */