nptl: Reinstate pthread_timedjoin_np as a cancellation point (BZ#24215)

Patch ce7eb0e90315 ("nptl: Cleanup cancellation macros") changed the
join sequence for internal common __pthread_timedjoin_ex to use the
new macro lll_wait_tid.  The idea was this macro would issue the
cancellable futex operation depending whether the timeout is used or
not.  However if a timeout is used, __lll_timedwait_tid is called and
it is not a cancellable entrypoint.

This patch fixes it by simplifying the code in various ways:

  - Instead of adding the cancellation handling on __lll_timedwait_tid,
    it moves the generic implementation to pthread_join_common.c (called
    now timedwait_tid with some fixes to use the correct type for pid).

  - The llvm_wait_tid macro is removed, along with its replication on
    x86_64, i686, and sparc arch-specific lowlevellock.h.

  - sparc32 __lll_timedwait_tid is also removed, since the code is similar
    to generic one.

  - x86_64 and i386 provides arch-specific __lll_timedwait_tid which is
    also removed since they are similar in functionality to generic C code
    and there is no indication it is better than compiler generated code.

New tests, tst-join8 and tst-join9, are provided to check if
pthread_timedjoin_np acts as a cancellation point.

Checked on x86_64-linux-gnu, i686-linux-gnu, sparcv9-linux-gnu, and
aarch64-linux-gnu.

	[BZ #24215]
	* nptl/Makefile (lpthread-routines): Remove lll_timedwait_tid.
	(tests): Add tst-join8 tst-join9.
	* nptl/lll_timedwait_tid.c: Remove file.
	* sysdeps/sparc/sparc32/lll_timedwait_tid.c: Likewise.
	* sysdeps/unix/sysv/linux/i386/lll_timedwait_tid.c: Likewise.
	* sysdeps/sysv/linux/x86_64/lll_timedwait_tid.c: Likewise.
	* nptl/pthread_join_common.c (timedwait_tid): New function.
	(__pthread_timedjoin_ex): Act as cancellation entrypoint is block
	is set.
	* nptl/tst-join5.c (thread_join): New function.
	(tf1, tf2, do_test): Use libsupport and add pthread_timedjoin_np
	check.
	* nptl/tst-join8.c: New file.
	* nptl/tst-join9.c: Likewise.
	* sysdeps/nptl/lowlevellock-futex.h (lll_futex_wait_cancel,
	lll_futex_timed_wait_cancel): Add generic macros.
	* sysdeps/nptl/lowlevellock.h (__lll_timedwait_tid, lll_wait_tid):
	Remove definitions.
	* sysdeps/unix/sysv/linux/i386/lowlevellock.h: Likewise.
	* sysdeps/unix/sysv/linux/sparc/lowlevellock.h: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/lowlevellock.h: Likewise.
	* sysdeps/sparc/sparc32/lowlevellock.c (__lll_timedwait_tid):
	Remove function.
	* sysdeps/unix/sysv/linux/i386/lowlevellock.S (__lll_timedwait_tid):
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/lowlevellock.S: Likewise.
	* sysdeps/unix/sysv/linux/lowlevellock-futex.h
	(lll_futex_timed_wait_cancel): New macro.

2 files changed, 7 insertions, 26 deletions

diff --git a/sysdeps/nptl/lowlevellock-futex.h b/sysdeps/nptl/lowlevellock-futex.h
index 50ceba7..bb8effe 100644
--- a/sysdeps/nptl/lowlevellock-futex.h
+++ b/sysdeps/nptl/lowlevellock-futex.h
@@ -82,5 +82,12 @@
                                  val, private)                          \
   -ENOSYS
 
+/* Like lll_futex_wait, but acting as a cancellable entrypoint.  */
+#define lll_futex_wait_cancel(futexp, val, private) \
+  -ENOSYS
+
+/* Like lll_futex_timed_wait, but acting as a cancellable entrypoint.  */
+#define lll_futex_timed_wait_cancel(futexp, val, timeout, private) \
+  -ENOSYS
 
 #endif  /* lowlevellock-futex.h */
diff --git a/sysdeps/nptl/lowlevellock.h b/sysdeps/nptl/lowlevellock.h
index 36bbc47..6f017af 100644
--- a/sysdeps/nptl/lowlevellock.h
+++ b/sysdeps/nptl/lowlevellock.h
@@ -175,30 +175,4 @@ extern int __lll_timedlock_wait (int *futex, const struct timespec *,
 #define LLL_LOCK_INITIALIZER		(0)
 #define LLL_LOCK_INITIALIZER_LOCKED	(1)
 
-extern int __lll_timedwait_tid (int *, const struct timespec *)
-     attribute_hidden;
-
-/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
-   wake-up when the clone terminates.  The memory location contains the
-   thread ID while the clone is running and is reset to zero by the kernel
-   afterwards.  The kernel up to version 3.16.3 does not use the private futex
-   operations for futex wake-up when the clone terminates.
-   If ABSTIME is not NULL, is used a timeout for futex call.  If the timeout
-   occurs then return ETIMEOUT, if ABSTIME is invalid, return EINVAL.
-   The futex operation are issues with cancellable versions.  */
-#define lll_wait_tid(tid, abstime)					\
-  ({									\
-    int __res = 0;							\
-    __typeof (tid) __tid;						\
-    if (abstime != NULL)						\
-      __res = __lll_timedwait_tid (&(tid), (abstime));			\
-    else								\
-      /* We need acquire MO here so that we synchronize with the 	\
-	 kernel's store to 0 when the clone terminates. (see above)  */	\
-      while ((__tid = atomic_load_acquire (&(tid))) != 0)		\
-        lll_futex_wait_cancel (&(tid), __tid, LLL_SHARED);		\
-    __res;								\
-  })
-
-
 #endif	/* lowlevellock.h */