diff mbox

[6/8] nptl: Fix Race conditions in pthread cancellation

Message ID 5435AD86.7030407@linux.vnet.ibm.com
State Dropped
Headers show

Commit Message

Adhemerval Zanella Netto Oct. 8, 2014, 9:32 p.m. UTC
bThis patches fixes some race conditions in NPTL cancellation code by
redefining how cancellable syscalls are defined and handled.  Current
approach is to enable asynchronous cancellation prior to making the syscall
and restore the previous cancellation type once the syscall returns.

As decribed in BZ#12683, this approach shows 2 important problems:

1. Cancellation can act after the syscall has returned from kernel, but
   before userspace saves the return value.  It might result in a resource
   leak if the syscall allocated a resource or a side effect (partial
   read/write), and there is no way to program handle it with cancellation
   handlers.

2. If a signal is handled while the thread is blocked at a cancellable
   syscall, the entire signal handler runs with asynchronous cancellation
   enabled.  This can lead to issues if the signal handler call functions
   which are async-signal-safe but not async-cancel-safe.

For cancellation to work correctly, there are 5 points at which the
cancellation signal could arrive:

1. Before the final testcancel before the syscall is made.
2. Between the testcancel and the syscall.
3. While the syscall is blocked and no side effects have yet taken place.
4. While the syscall is blocked but with some side effects already having
   taken place (e.g. a partial read or write).
5. After the syscall has returned.

And GLIBC wants to act on cancellation in cases 1, 2, and 3 but not in case
4 or 5.  The proposed solution follows:

* Handling case 1 is trivial: do a conditional branch based on whether the
  thread has received a cancellation request;
* Case 2 can be caught by the signal handler determining that the saved
  program counter (from the ucontext_t) is in some address range beginning
  just before the "testcancel" and ending with the syscall instruction.
* In this case, except for certain syscalls that ALWAYS fail with EINTR
  even for non-interrupting signals, the kernel will reset the program
  counter to point at the syscall instruction during signal handling, so
  that the syscall is restarted when the signal handler returns. So, from
  the signal handler's standpoint, this looks the same as case 2, and thus
  it's taken care of.
* In this case, the kernel cannot restart the syscall; when it's
  interrupted by a signal, the kernel must cause the syscall to return
  with whatever partial result it obtained (e.g. partial read or write).
* In this case, the saved program counter points just after the syscall
  instruction, so the signal handler won't act on cancellation.
  This one is equal to 4. since the program counter is past the syscall
  instruction already.

Another case that needs handling is syscalls that fail with EINTR even
when the signal handler is non-interrupting. In this case, the syscall
wrapper code can just check the cancellation flag when the errno result
is EINTR, and act on cancellation if it's set.

The proposed GLIBC adjustments are:

1. Remove the enable_asynccancel/disable_asynccancel function usage in
   syscall definition and instead make them call a common symbol that will
   check if cancellation is enabled, call the arch-specific cancellable
   entry-point and cancel the thread when required.
2. Provide a arch-specific symbol that contains global markers. These
   markers will be used in SIGCANCEL handler to check if the interruption
   has been called in a valid syscall and if the syscalls has been
   completed or not.
3. Rewrite SIGCANCEL asynchronous handler to check for both cancelling type
   and if current IP from signal handler falls between the global markes
   and act accordingly.
4. Adjust nptl/pthread_cancel.c to send an signal instead of acting
   directly. This avoid synchronization issues about updating the
   cancellation status and also focus the logic on signal handler and
   cancellation syscall code.
5. Adjust pthread code to replace CANCEL_ASYNC/CANCEL_RESET calls to
   appropriated cancelable futex syscalls.
6. Adjust libc code to replace LIBC_CANCEL_ASYNC/LIBC_CANCEL_RESET to
   appropriated cancelable syscalls.
7. Adjust 'lowlevellock.h' arch-specific implementations to provide
   cancelable futex calls (used in libpthread code).

This patch adds the proposed changes to NPTL and the changes required
for powerpc64.

--

	* nptl/Makefile [routines]: Add syscall_cancel object.
	[libpthread-routines]: Remove cancellation object.
	* nptl/Versions (libc) [GLIBC_PRIVATE]: Add __syscall_cancel,
	__syscall_cancel_arch_start, and __syscall_cancel_arch_end.
	* nptl/cancellation.c: Remove file.
	* nptl/descr.h (CANCELING_BIT): Remove define.
	(CANCELING_BITMASK): Likewise.
	(CANCEL_RESTMASK): Adjust value with CANCELED_BIT remove.
	* nptl/libc-cancellation.c (__syscall_cancel): Add non-cancellable
	implementation for loader and cancellable one for libc.
	(__syscall_do_cancel): New function: cancel call for syscall wrappers.
	* nptl/lowlevellock.c (__lll_timedwait_tid): Using cancellable futex
	call.
	* nptl/nptl-init.c (sigcancel_handler): Rewrite function to avoid race
	conditions.
	* nptl/pt-system.c [LIBC_CANCEL_HANDLED]: Remove definition.
	* nptl/pthreadP.h (__do_cancel): Rewrite to both disable asynchronous
	cancellation and setting the thread as cancelled.
	(CANCEL_ASYNC): Remove definition.
	(CANCEL_RESET): Likewise.
	(LIBC_CANCEL_ASYNC): Likewise.
	(LIBC_CANCEL_RESET): Likewise.
	(LIBC_CANCEL_HANDLED): Likewise.
	(__syscall_cancel_arch): Add prototype.
	(__pthread_enable_asynccancel): Remove prototype.
	(__pthread_disable_asynccancel): Likewise.
	(__libc_enable_asynccancel): Likewise.
	(__libc_disable_asynccancel): Likewise.
	(__librt_enable_asynccancel): Likewise.
	(__librt_disable_asynccancel): Likewise.
	(__syscall_cancel): Add prototype.
	* nptl/pthread_cancel.c (pthread_cancel): Rewrite to just set
	CANCELLED_BIT and call __pthread_kill.
	* nptl/pthread_cond_timedwait.c (__pthread_cond_timedwait): Remove
	calls to enable/disable asynchronous cancellation and use call to
	cancellable syscall entrypoint when required.
	* nptl/pthread_cond_wait.c (__pthread_cond_wait): Likewise.
	* nptl/pthread_create.c (start_thread): Likewise.
	* nptl/pthread_timedjoin.c (pthread_timedjoin_np): Likewise.
	* nptl/sem_timedwait.c (sem_timedwait):  Likewise.
	* nptl/sem_wait.c (__new_sem_wait): Likewise.
	* sysdeps/nptl/aio_misc.h (AIO_MISC_WAIT): Likewise.
	* sysdeps/nptl/gai_misc.h (GAI_MISC_WAIT): Likewise.
	* sysdeps/posix/sigpause.c (do_sigpause): Likewise.
	* sysdeps/posix/waitid.c (__waitid): Likewise.
	* sysdeps/nptl/lowlevellock.h (lll_wait_tid): Likewise.
	* nptl/pthread_exit.c (pthread_exit): Rewrite to set EXITING_BIT
	before call __pthread_unwind.
	* nptl/pthread_join.c (pthread_join): Remove CANCEL_ASYNC/CANCEL_RESET
	usage.
	* rt/Makefile [CFLAGS-librt-cancellation.c]: Remove rule.
	* sysdeps/generic/sysdep-cancel.h [LIBC_CANCEL_ASYNC]: Likewise.
	[LIBC_CANCEL_RESET]: Likewise.
	[LIBC_CANCEL_HANDLED]: Likewise.
	* sysdeps/unix/sysv/linux/clock_nanosleep.c (__clock_nanosleep):
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/fcntl.c (__libc_fnctl):
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/socket.S (__socket):
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep-cancel.h (PSEUDO):
	Likewise.
	* sysdeps/nptl/Makefile [librt-sysdep_routines]: Remove rule.
	* sysdeps/nptl/librt-cancellation.c: Remove file.
	* sysdeps/unix/sysv/linux/lowlevellock-futex.h (lll_futex_wait_cancel):
	New define: cancellable futex wait.
	(lll_futex_timed_wait_cancel): New define: cancellable timed wait.
	(lll_futex_timed_wait_bitset_cancel): New define: cancellable timed
	wait bitset.
	(lll_futex_wait_requeue_pi_cancel): New define: cancellable wait
	requeue PI futex.
	(lll_futex_timed_wait_requeue_pi_cancel): New define: cancellable time
	wait requeue PI futex.
	(lll_wait_tid): Use cancellable futex wait call.
	* sysdeps/powerpc/nptl/pthreaddef.h (__pthread_get_ip): New function:
	return ucontext_t instruction point address.
	* sysdeps/unix/sysdep.h (SYSCALL_CANCEL): New macro: cancelable
	syscall calls.
	* sysdeps/generic/sysdep-cancel.h (LIBC_CANCEL_ASYNC): Remove define.
	(LIBC_CANCEL_RESET): Likewise.
	(LIBC_CANCEL_HANDLED): Likewise.
	* sysdeps/unix/sysv/linux/pthread_kill.c (__pthread_kill): Allow
	SIGCANCEL to be sent.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h
	(SYSCALL_CANCEL_ERROR): New define.
	(SYSCALL_CANCEL_ERRNO): New define.
	* sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S: New file:
	cancellable syscall.
	* sysdeps/unix/sysv/linux/powerpc/sysdep.c (__syscall_cancel_error):
	New symbol: cancellable syscall error handler.
---
diff mbox

Patch

diff --git a/nptl/Makefile b/nptl/Makefile
index cb4bdd7..7d68dad 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -30,7 +30,7 @@  install-lib-ldscripts := libpthread.so
 
 routines = alloca_cutoff forward libc-lowlevellock libc-cancellation \
 	   libc-cleanup libc_pthread_init libc_multiple_threads \
-	   register-atfork unregister-atfork
+	   register-atfork unregister-atfork syscall_cancel
 shared-only-routines = forward
 
 libpthread-routines = nptl-init vars events version \
@@ -103,7 +103,6 @@  libpthread-routines = nptl-init vars events version \
 		      cleanup cleanup_defer cleanup_compat \
 		      cleanup_defer_compat unwind \
 		      pt-longjmp pt-cleanup\
-		      cancellation \
 		      lowlevellock lowlevelrobustlock \
 		      pt-fork pt-vfork \
 		      ptw-write ptw-read ptw-close ptw-fcntl ptw-accept \
@@ -156,7 +155,6 @@  CFLAGS-pthread_setcanceltype.c = -fexceptions -fasynchronous-unwind-tables
 
 # These are internal functions which similar functionality as setcancelstate
 # and setcanceltype.
-CFLAGS-cancellation.c = -fasynchronous-unwind-tables
 CFLAGS-libc-cancellation.c = -fasynchronous-unwind-tables
 
 # Calling pthread_exit() must cause the registered cancel handlers to
diff --git a/nptl/Versions b/nptl/Versions
index b7d4a9b..4114bc9 100644
--- a/nptl/Versions
+++ b/nptl/Versions
@@ -36,6 +36,9 @@  libc {
     __libc_pthread_init;
     __libc_current_sigrtmin_private; __libc_current_sigrtmax_private;
     __libc_allocate_rtsig_private;
+    __syscall_cancel;
+    __syscall_cancel_arch_start;
+    __syscall_cancel_arch_end;
   }
 }
 
diff --git a/nptl/cancellation.c b/nptl/cancellation.c
deleted file mode 100644
index aaf102d..0000000
--- a/nptl/cancellation.c
+++ /dev/null
@@ -1,99 +0,0 @@ 
-/* Copyright (C) 2002-2014 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
-
-   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 <setjmp.h>
-#include <stdlib.h>
-#include "pthreadP.h"
-
-
-/* The next two functions are similar to pthread_setcanceltype() but
-   more specialized for the use in the cancelable functions like write().
-   They do not need to check parameters etc.  */
-int
-attribute_hidden
-__pthread_enable_asynccancel (void)
-{
-  struct pthread *self = THREAD_SELF;
-  int oldval = THREAD_GETMEM (self, cancelhandling);
-
-  while (1)
-    {
-      int newval = oldval | CANCELTYPE_BITMASK;
-
-      if (newval == oldval)
-	break;
-
-      int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
-					      oldval);
-      if (__glibc_likely (curval == oldval))
-	{
-	  if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
-	    {
-	      THREAD_SETMEM (self, result, PTHREAD_CANCELED);
-	      __do_cancel ();
-	    }
-
-	  break;
-	}
-
-      /* Prepare the next round.  */
-      oldval = curval;
-    }
-
-  return oldval;
-}
-
-
-void
-internal_function attribute_hidden
-__pthread_disable_asynccancel (int oldtype)
-{
-  /* If asynchronous cancellation was enabled before we do not have
-     anything to do.  */
-  if (oldtype & CANCELTYPE_BITMASK)
-    return;
-
-  struct pthread *self = THREAD_SELF;
-  int newval;
-
-  int oldval = THREAD_GETMEM (self, cancelhandling);
-
-  while (1)
-    {
-      newval = oldval & ~CANCELTYPE_BITMASK;
-
-      int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
-					      oldval);
-      if (__glibc_likely (curval == oldval))
-	break;
-
-      /* Prepare the next round.  */
-      oldval = curval;
-    }
-
-  /* We cannot return when we are being canceled.  Upon return the
-     thread might be things which would have to be undone.  The
-     following loop should loop until the cancellation signal is
-     delivered.  */
-  while (__builtin_expect ((newval & (CANCELING_BITMASK | CANCELED_BITMASK))
-			   == CANCELING_BITMASK, 0))
-    {
-      lll_futex_wait (&self->cancelhandling, newval, LLL_PRIVATE);
-      newval = THREAD_GETMEM (self, cancelhandling);
-    }
-}
diff --git a/nptl/descr.h b/nptl/descr.h
index 6738591..a5b0b29 100644
--- a/nptl/descr.h
+++ b/nptl/descr.h
@@ -263,23 +263,20 @@  struct pthread
   /* Bit set if asynchronous cancellation mode is selected.  */
 #define CANCELTYPE_BIT		1
 #define CANCELTYPE_BITMASK	(0x01 << CANCELTYPE_BIT)
-  /* Bit set if canceling has been initiated.  */
-#define CANCELING_BIT		2
-#define CANCELING_BITMASK	(0x01 << CANCELING_BIT)
-  /* Bit set if canceled.  */
-#define CANCELED_BIT		3
+  /* Bit set if threads is canceled.  */
+#define CANCELED_BIT		2
 #define CANCELED_BITMASK	(0x01 << CANCELED_BIT)
   /* Bit set if thread is exiting.  */
-#define EXITING_BIT		4
+#define EXITING_BIT		3
 #define EXITING_BITMASK		(0x01 << EXITING_BIT)
   /* Bit set if thread terminated and TCB is freed.  */
-#define TERMINATED_BIT		5
+#define TERMINATED_BIT		4
 #define TERMINATED_BITMASK	(0x01 << TERMINATED_BIT)
   /* Bit set if thread is supposed to change XID.  */
-#define SETXID_BIT		6
+#define SETXID_BIT		5
 #define SETXID_BITMASK		(0x01 << SETXID_BIT)
   /* Mask for the rest.  Helps the compiler to optimize.  */
-#define CANCEL_RESTMASK		0xffffff80
+#define CANCEL_RESTMASK		0xffffffc0
 
 #define CANCEL_ENABLED_AND_CANCELED(value) \
   (((value) & (CANCELSTATE_BITMASK | CANCELED_BITMASK | EXITING_BITMASK	      \
diff --git a/nptl/libc-cancellation.c b/nptl/libc-cancellation.c
index c2c1fbb..5cb0d7d 100644
--- a/nptl/libc-cancellation.c
+++ b/nptl/libc-cancellation.c
@@ -16,9 +16,63 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#include <setjmp.h>
+#include <stdlib.h>
 #include "pthreadP.h"
 
+#ifdef IS_IN_rtld
 
-#define __pthread_enable_asynccancel __libc_enable_asynccancel
-#define __pthread_disable_asynccancel __libc_disable_asynccancel
-#include <nptl/cancellation.c>
+long int
+__syscall_cancel (__syscall_arg_t nr, __syscall_arg_t arg1,
+		  __syscall_arg_t arg2, __syscall_arg_t arg3,
+		  __syscall_arg_t arg4, __syscall_arg_t arg5,
+		  __syscall_arg_t arg6)
+{
+  INTERNAL_SYSCALL_DECL (err);
+  return INTERNAL_SYSCALL_NCS (nr, err, 6, arg1, arg2, arg3, arg4, arg5, arg6);
+}
+
+#else
+
+/* Cancellation function called by all cancellable syscalls.  */
+long int
+__syscall_cancel (__syscall_arg_t nr, __syscall_arg_t a1,
+		  __syscall_arg_t a2, __syscall_arg_t a3,
+		  __syscall_arg_t a4, __syscall_arg_t a5,
+		  __syscall_arg_t a6)
+{
+  pthread_t self = (pthread_t) THREAD_SELF;
+  volatile struct pthread *pd = (volatile struct pthread *) self;
+  long int result;
+
+  /* If cancellation is not enabled, call the syscall directly.  */
+  if (pd->cancelhandling & CANCELSTATE_BITMASK)
+    {
+      INTERNAL_SYSCALL_DECL (err);
+      result = INTERNAL_SYSCALL_NCS (nr, err, 6, a1, a2, a3, a4, a5, a6);
+      return INTERNAL_SYSCALL_ERROR_P (result, err) ? -result : result;
+    }
+
+  /* Call the arch-specific entry points that contains the globals markers
+     to be checked by SIGCANCEL handler.  */
+  result = __syscall_cancel_arch (&pd->cancelhandling, nr, a1, a2, a3, a4, a5,
+			          a6);
+
+  if ((result == -EINTR)
+      && (pd->cancelhandling & CANCELED_BITMASK)
+      && !(pd->cancelhandling & CANCELSTATE_BITMASK))
+    __do_cancel ();
+
+  return result;
+}
+libc_hidden_def (__syscall_cancel)
+
+/* Since __do_cancel is a always inline function, this creates a symbol the
+   arch-specific symbol can call to cancel the thread.  */
+void
+__syscall_do_cancel (void)
+{
+  __do_cancel ();
+}
+
+#endif
diff --git a/nptl/lowlevellock.c b/nptl/lowlevellock.c
index e198af7..0ff4ac3 100644
--- a/nptl/lowlevellock.c
+++ b/nptl/lowlevellock.c
@@ -115,7 +115,7 @@  __lll_timedwait_tid (int *tidp, const struct timespec *abstime)
 
       /* Wait until thread terminates.  The kernel so far does not use
 	 the private futex operations for this.  */
-      if (lll_futex_timed_wait (tidp, tid, &rt, LLL_SHARED) == -ETIMEDOUT)
+      if (lll_futex_timed_wait_cancel (tidp, tid, &rt, LLL_SHARED) == -ETIMEDOUT)
 	return ETIMEDOUT;
     }
 
diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
index 9f7b20a..cad7d11 100644
--- a/nptl/nptl-init.c
+++ b/nptl/nptl-init.c
@@ -188,36 +188,41 @@  sigcancel_handler (int sig, siginfo_t *si, void *ctx)
     return;
 
   struct pthread *self = THREAD_SELF;
+  volatile struct pthread *pd = (volatile struct pthread *) self;
+  ucontext_t *uc = ctx;
+  const char *tip = (const char *)__pthread_get_ip (ctx);
 
-  int oldval = THREAD_GETMEM (self, cancelhandling);
-  while (1)
+  extern const char __syscall_cancel_arch_start[1];
+  extern const char __syscall_cancel_arch_end[1];
+
+  if (((pd->cancelhandling & (CANCELSTATE_BITMASK)) != 0)
+      || ((pd->cancelhandling & CANCELED_BITMASK) == 0))
+    return;
+
+  __sigaddset (&uc->uc_sigmask, SIGCANCEL);
+
+  /* Check if asynchronous cancellation mode is set and if interrupted
+     instruction pointer falls within the cancellable syscall code.  For
+     interruptable syscalls that might generate external side-effects (partial
+     reads or writes, for instance), the kernel will set the IP to after
+     '__syscall_cancel_arch_end', thus disabling the cancellation and allowing
+     the process to handle such conditions.  */
+  if (pd->cancelhandling & CANCELTYPE_BITMASK ||
+      (tip >= __syscall_cancel_arch_start && tip < __syscall_cancel_arch_end))
     {
-      /* We are canceled now.  When canceled by another thread this flag
-	 is already set but if the signal is directly send (internally or
-	 from another process) is has to be done here.  */
-      int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
-
-      if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
-	/* Already canceled or exiting.  */
-	break;
-
-      int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
-					      oldval);
-      if (curval == oldval)
-	{
-	  /* Set the return value.  */
-	  THREAD_SETMEM (self, result, PTHREAD_CANCELED);
-
-	  /* Make sure asynchronous cancellation is still enabled.  */
-	  if ((newval & CANCELTYPE_BITMASK) != 0)
-	    /* Run the registered destructors and terminate the thread.  */
-	    __do_cancel ();
-
-	  break;
-	}
-
-      oldval = curval;
+      THREAD_ATOMIC_BIT_SET (self, cancelhandling, EXITING_BIT);
+      THREAD_SETMEM (self, result, PTHREAD_CANCELED);
+
+      /* __pthread_sigmask removes SIGCANCEL from the set.  */
+      INTERNAL_SYSCALL_DECL (err);
+      INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIGCANCEL, &uc->uc_sigmask, 0,
+                        _NSIG / 8);
+
+      __do_cancel ();
     }
+
+  INLINE_SYSCALL (tgkill, 3, THREAD_GETMEM (THREAD_SELF, pid), pd->tid,
+		  SIGCANCEL);
 }
 
 
@@ -375,7 +380,10 @@  __pthread_initialize_minimal_internal (void)
      it is only asynchronous cancellation which is affected.  */
   struct sigaction sa;
   sa.sa_sigaction = sigcancel_handler;
-  sa.sa_flags = SA_SIGINFO;
+  /* The signal handle should be non-interruptible to avoid the risk of
+     spurious EINTR caused by SIGCANCEL sent to process or if pthread_cancel
+     is called while cancellation is disabled in the target thread.  */
+  sa.sa_flags = SA_SIGINFO | SA_RESTART;
   __sigemptyset (&sa.sa_mask);
 
   (void) __libc_sigaction (SIGCANCEL, &sa, NULL);
diff --git a/nptl/pt-system.c b/nptl/pt-system.c
index 4fc1bf2..20d976a 100644
--- a/nptl/pt-system.c
+++ b/nptl/pt-system.c
@@ -27,6 +27,3 @@  system (const char *line)
 {
   return __libc_system (line);
 }
-
-/* __libc_system in libc.so handles cancellation.  */
-LIBC_CANCEL_HANDLED ();
diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
index d4415ba..2643a99 100644
--- a/nptl/pthreadP.h
+++ b/nptl/pthreadP.h
@@ -272,49 +272,31 @@  __do_cancel (void)
   struct pthread *self = THREAD_SELF;
 
   /* Make sure we get no more cancellations.  */
-  THREAD_ATOMIC_BIT_SET (self, cancelhandling, EXITING_BIT);
+  int oldval = THREAD_GETMEM (self, cancelhandling);
+  while (1)
+    {
+      int newval = (oldval | CANCELSTATE_BITMASK);
+      newval &= ~(CANCELTYPE_BITMASK);
+      if (oldval == newval)
+	break;
+
+      int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
+					  oldval);
+      if (__glibc_likely (curval == oldval))
+	break;
+      oldval = curval;
+    }
+
+  THREAD_SETMEM (self, result, PTHREAD_CANCELED);
 
   __pthread_unwind ((__pthread_unwind_buf_t *)
 		    THREAD_GETMEM (self, cleanup_jmp_buf));
 }
 
-
-/* Set cancellation mode to asynchronous.  */
-#define CANCEL_ASYNC() \
-  __pthread_enable_asynccancel ()
-/* Reset to previous cancellation mode.  */
-#define CANCEL_RESET(oldtype) \
-  __pthread_disable_asynccancel (oldtype)
-
-#if !defined NOT_IN_libc
-/* Same as CANCEL_ASYNC, but for use in libc.so.  */
-# define LIBC_CANCEL_ASYNC() \
-  __libc_enable_asynccancel ()
-/* Same as CANCEL_RESET, but for use in libc.so.  */
-# define LIBC_CANCEL_RESET(oldtype) \
-  __libc_disable_asynccancel (oldtype)
-# define LIBC_CANCEL_HANDLED() \
-  __asm (".globl " __SYMBOL_PREFIX "__libc_enable_asynccancel"); \
-  __asm (".globl " __SYMBOL_PREFIX "__libc_disable_asynccancel")
-#elif defined IS_IN_libpthread
-# define LIBC_CANCEL_ASYNC() CANCEL_ASYNC ()
-# define LIBC_CANCEL_RESET(val) CANCEL_RESET (val)
-# define LIBC_CANCEL_HANDLED() \
-  __asm (".globl " __SYMBOL_PREFIX "__pthread_enable_asynccancel"); \
-  __asm (".globl " __SYMBOL_PREFIX "__pthread_disable_asynccancel")
-#elif defined IS_IN_librt
-# define LIBC_CANCEL_ASYNC() \
-  __librt_enable_asynccancel ()
-# define LIBC_CANCEL_RESET(val) \
-  __librt_disable_asynccancel (val)
-# define LIBC_CANCEL_HANDLED() \
-  __asm (".globl " __SYMBOL_PREFIX "__librt_enable_asynccancel"); \
-  __asm (".globl " __SYMBOL_PREFIX "__librt_disable_asynccancel")
-#else
-# define LIBC_CANCEL_ASYNC()	0 /* Just a dummy value.  */
-# define LIBC_CANCEL_RESET(val)	((void)(val)) /* Nothing, but evaluate it.  */
-# define LIBC_CANCEL_HANDLED()	/* Nothing.  */
-#endif
+extern long int __syscall_cancel_arch (volatile void *, __syscall_arg_t nr,
+     __syscall_arg_t arg1, __syscall_arg_t arg2, __syscall_arg_t arg3,
+     __syscall_arg_t arg4, __syscall_arg_t arg5, __syscall_arg_t arg6);
+libc_hidden_proto (__syscall_cancel_arch);
 
 
 /* Internal prototypes.  */
@@ -482,9 +464,6 @@  extern int __pthread_equal (pthread_t thread1, pthread_t thread2);
 extern int __pthread_kill (pthread_t threadid, int signo);
 extern void __pthread_exit (void *value) __attribute__ ((__noreturn__));
 extern int __pthread_setcanceltype (int type, int *oldtype);
-extern int __pthread_enable_asynccancel (void) attribute_hidden;
-extern void __pthread_disable_asynccancel (int oldtype)
-     internal_function attribute_hidden;
 
 #ifdef IS_IN_libpthread
 hidden_proto (__pthread_mutex_init)
@@ -514,16 +493,6 @@  extern int __pthread_cond_wait_2_0 (pthread_cond_2_0_t *cond,
 extern int __pthread_getaffinity_np (pthread_t th, size_t cpusetsize,
 				     cpu_set_t *cpuset);
 
-/* The two functions are in libc.so and not exported.  */
-extern int __libc_enable_asynccancel (void) attribute_hidden;
-extern void __libc_disable_asynccancel (int oldtype)
-     internal_function attribute_hidden;
-
-
-/* The two functions are in librt.so and not exported.  */
-extern int __librt_enable_asynccancel (void) attribute_hidden;
-extern void __librt_disable_asynccancel (int oldtype)
-     internal_function attribute_hidden;
 
 #ifdef IS_IN_libpthread
 /* Special versions which use non-exported functions.  */
diff --git a/nptl/pthread_cancel.c b/nptl/pthread_cancel.c
index 057b5cc..58b398b 100644
--- a/nptl/pthread_cancel.c
+++ b/nptl/pthread_cancel.c
@@ -18,11 +18,10 @@ 
 
 #include <errno.h>
 #include <signal.h>
-#include "pthreadP.h"
-#include "atomic.h"
+#include <pthreadP.h>
+#include <atomic.h>
 #include <sysdep.h>
 
-
 int
 pthread_cancel (pthread_t th)
 {
@@ -36,67 +35,17 @@  pthread_cancel (pthread_t th)
 #ifdef SHARED
   pthread_cancel_init ();
 #endif
-  int result = 0;
-  int oldval;
-  int newval;
-  do
-    {
-    again:
-      oldval = pd->cancelhandling;
-      newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
-
-      /* Avoid doing unnecessary work.  The atomic operation can
-	 potentially be expensive if the bug has to be locked and
-	 remote cache lines have to be invalidated.  */
-      if (oldval == newval)
-	break;
-
-      /* If the cancellation is handled asynchronously just send a
-	 signal.  We avoid this if possible since it's more
-	 expensive.  */
-      if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval))
-	{
-	  /* Mark the cancellation as "in progress".  */
-	  if (atomic_compare_and_exchange_bool_acq (&pd->cancelhandling,
-						    oldval | CANCELING_BITMASK,
-						    oldval))
-	    goto again;
-
-	  /* The cancellation handler will take care of marking the
-	     thread as canceled.  */
-	  INTERNAL_SYSCALL_DECL (err);
-
-	  /* One comment: The PID field in the TCB can temporarily be
-	     changed (in fork).  But this must not affect this code
-	     here.  Since this function would have to be called while
-	     the thread is executing fork, it would have to happen in
-	     a signal handler.  But this is no allowed, pthread_cancel
-	     is not guaranteed to be async-safe.  */
-	  int val;
-	  val = INTERNAL_SYSCALL (tgkill, err, 3,
-				  THREAD_GETMEM (THREAD_SELF, pid), pd->tid,
-				  SIGCANCEL);
-
-	  if (INTERNAL_SYSCALL_ERROR_P (val, err))
-	    result = INTERNAL_SYSCALL_ERRNO (val, err);
-
-	  break;
-	}
 
-	/* A single-threaded process should be able to kill itself, since there is
-	   nothing in the POSIX specification that says that it cannot.  So we set
-	   multiple_threads to true so that cancellation points get executed.  */
-	THREAD_SETMEM (THREAD_SELF, header.multiple_threads, 1);
+  THREAD_ATOMIC_BIT_SET (pd, cancelhandling, CANCELED_BIT);
+  /* A single-threaded process should be able to kill itself, since there is
+     nothing in the POSIX specification that says that it cannot.  So we set
+     multiple_threads to true so that cancellation points get executed.  */
+  THREAD_SETMEM (THREAD_SELF, header.multiple_threads, 1);
 #ifndef TLS_MULTIPLE_THREADS_IN_TCB
-	__pthread_multiple_threads = *__libc_multiple_threads_ptr = 1;
+  __pthread_multiple_threads = *__libc_multiple_threads_ptr = 1;
 #endif
-    }
-  /* Mark the thread as canceled.  This has to be done
-     atomically since other bits could be modified as well.  */
-  while (atomic_compare_and_exchange_bool_acq (&pd->cancelhandling, newval,
-					       oldval));
 
-  return result;
+  return __pthread_kill (th, SIGCANCEL);
 }
 
 PTHREAD_STATIC_FN_REQUIRE (pthread_create)
diff --git a/nptl/pthread_cond_timedwait.c b/nptl/pthread_cond_timedwait.c
index f8f4d38..7c457c2 100644
--- a/nptl/pthread_cond_timedwait.c
+++ b/nptl/pthread_cond_timedwait.c
@@ -41,7 +41,6 @@  extern void __condvar_cleanup (void *arg)
 
 struct _condvar_cleanup_buffer
 {
-  int oldtype;
   pthread_cond_t *cond;
   pthread_mutex_t *mutex;
   unsigned int bc_seq;
@@ -62,7 +61,7 @@  __pthread_cond_timedwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
   int pshared = (cond->__data.__mutex == (void *) ~0l)
 		? LLL_SHARED : LLL_PRIVATE;
 
-#if (defined lll_futex_timed_wait_requeue_pi \
+#if (defined lll_futex_timed_wait_requeue_pi_cancel \
      && defined __ASSUME_REQUEUE_PI)
   int pi_flag = 0;
 #endif
@@ -155,12 +154,9 @@  __pthread_cond_timedwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
       /* Prepare to wait.  Release the condvar futex.  */
       lll_unlock (cond->__data.__lock, pshared);
 
-      /* Enable asynchronous cancellation.  Required by the standard.  */
-      cbuffer.oldtype = __pthread_enable_asynccancel ();
-
 /* REQUEUE_PI was implemented after FUTEX_CLOCK_REALTIME, so it is sufficient
    to check just the former.  */
-#if (defined lll_futex_timed_wait_requeue_pi \
+#if (defined lll_futex_timed_wait_requeue_pi_cancel \
      && defined __ASSUME_REQUEUE_PI)
       /* If pi_flag remained 1 then it means that we had the lock and the mutex
 	 but a spurious waker raced ahead of us.  Give back the mutex before
@@ -176,10 +172,11 @@  __pthread_cond_timedwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
 	{
 	  unsigned int clockbit = (cond->__data.__nwaiters & 1
 				   ? 0 : FUTEX_CLOCK_REALTIME);
-	  err = lll_futex_timed_wait_requeue_pi (&cond->__data.__futex,
-						 futex_val, abstime, clockbit,
-						 &mutex->__data.__lock,
-						 pshared);
+	  err = lll_futex_timed_wait_requeue_pi_cancel (&cond->__data.__futex,
+							futex_val, abstime,
+							clockbit,
+							&mutex->__data.__lock,
+							pshared);
 	  pi_flag = (err == 0);
 	}
       else
@@ -187,21 +184,19 @@  __pthread_cond_timedwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
 
 	{
 #if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
-     || !defined lll_futex_timed_wait_bitset)
+     || !defined lll_futex_timed_wait_bitset_cancel)
 	  /* Wait until woken by signal or broadcast.  */
-	  err = lll_futex_timed_wait (&cond->__data.__futex,
-				      futex_val, &rt, pshared);
+	  err = lll_futex_timed_wait_cancel (&cond->__data.__futex,
+					     futex_val, &rt, pshared);
 #else
 	  unsigned int clockbit = (cond->__data.__nwaiters & 1
 				   ? 0 : FUTEX_CLOCK_REALTIME);
-	  err = lll_futex_timed_wait_bitset (&cond->__data.__futex, futex_val,
-					     abstime, clockbit, pshared);
+	  err = lll_futex_timed_wait_bitset_cancel (&cond->__data.__futex,
+						    futex_val,abstime,
+						    clockbit, pshared);
 #endif
 	}
 
-      /* Disable asynchronous cancellation.  */
-      __pthread_disable_asynccancel (cbuffer.oldtype);
-
       /* We are going to look at shared data again, so get the lock.  */
       lll_lock (cond->__data.__lock, pshared);
 
diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
index 077abc4..4655369 100644
--- a/nptl/pthread_cond_wait.c
+++ b/nptl/pthread_cond_wait.c
@@ -29,7 +29,6 @@ 
 
 struct _condvar_cleanup_buffer
 {
-  int oldtype;
   pthread_cond_t *cond;
   pthread_mutex_t *mutex;
   unsigned int bc_seq;
@@ -106,7 +105,7 @@  __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex)
   int pshared = (cond->__data.__mutex == (void *) ~0l)
 		? LLL_SHARED : LLL_PRIVATE;
 
-#if (defined lll_futex_wait_requeue_pi \
+#if (defined lll_futex_wait_requeue_pi_cancel \
      && defined __ASSUME_REQUEUE_PI)
   int pi_flag = 0;
 #endif
@@ -157,10 +156,7 @@  __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex)
       /* Prepare to wait.  Release the condvar futex.  */
       lll_unlock (cond->__data.__lock, pshared);
 
-      /* Enable asynchronous cancellation.  Required by the standard.  */
-      cbuffer.oldtype = __pthread_enable_asynccancel ();
-
-#if (defined lll_futex_wait_requeue_pi \
+#if (defined lll_futex_wait_requeue_pi_cancel \
      && defined __ASSUME_REQUEUE_PI)
       /* If pi_flag remained 1 then it means that we had the lock and the mutex
 	 but a spurious waker raced ahead of us.  Give back the mutex before
@@ -174,19 +170,17 @@  __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex)
 
       if (pi_flag)
 	{
-	  err = lll_futex_wait_requeue_pi (&cond->__data.__futex,
-					   futex_val, &mutex->__data.__lock,
-					   pshared);
+	  err = lll_futex_wait_requeue_pi_cancel (&cond->__data.__futex,
+						  futex_val,
+						  &mutex->__data.__lock,
+						  pshared);
 
 	  pi_flag = (err == 0);
 	}
       else
 #endif
 	  /* Wait until woken by signal or broadcast.  */
-	lll_futex_wait (&cond->__data.__futex, futex_val, pshared);
-
-      /* Disable asynchronous cancellation.  */
-      __pthread_disable_asynccancel (cbuffer.oldtype);
+	lll_futex_wait_cancel (&cond->__data.__futex, futex_val, pshared);
 
       /* We are going to look at shared data again, so get the lock.  */
       lll_lock (cond->__data.__lock, pshared);
diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
index b9af010..8eee243 100644
--- a/nptl/pthread_create.c
+++ b/nptl/pthread_create.c
@@ -266,7 +266,7 @@  start_thread (void *arg)
   /* If the parent was running cancellation handlers while creating
      the thread the new thread inherited the signal mask.  Reset the
      cancellation signal mask.  */
-  if (__glibc_unlikely (pd->parent_cancelhandling & CANCELING_BITMASK))
+  if (__glibc_unlikely (pd->parent_cancelhandling & CANCELED_BITMASK))
     {
       INTERNAL_SYSCALL_DECL (err);
       sigset_t mask;
@@ -293,14 +293,10 @@  start_thread (void *arg)
 
       if (__glibc_unlikely (pd->stopped_start))
 	{
-	  int oldtype = CANCEL_ASYNC ();
-
 	  /* Get the lock the parent locked to force synchronization.  */
 	  lll_lock (pd->lock, LLL_PRIVATE);
 	  /* And give it up right away.  */
 	  lll_unlock (pd->lock, LLL_PRIVATE);
-
-	  CANCEL_RESET (oldtype);
 	}
 
       LIBC_PROBE (pthread_start, 3, (pthread_t) pd, pd->start_routine, pd->arg);
diff --git a/nptl/pthread_exit.c b/nptl/pthread_exit.c
index 0ec1ea6..4068bf5 100644
--- a/nptl/pthread_exit.c
+++ b/nptl/pthread_exit.c
@@ -23,9 +23,14 @@ 
 void
 __pthread_exit (void *value)
 {
-  THREAD_SETMEM (THREAD_SELF, result, value);
+  struct pthread *self = THREAD_SELF;
 
-  __do_cancel ();
+  THREAD_SETMEM (self, result, value);
+
+  THREAD_ATOMIC_BIT_SET (self, cancelhandling, EXITING_BIT);
+
+  __pthread_unwind ((__pthread_unwind_buf_t *)
+		    THREAD_GETMEM (self, cleanup_jmp_buf));
 }
 strong_alias (__pthread_exit, pthread_exit)
 
diff --git a/nptl/pthread_join.c b/nptl/pthread_join.c
index e822bbd..88ae5c9 100644
--- a/nptl/pthread_join.c
+++ b/nptl/pthread_join.c
@@ -61,13 +61,10 @@  pthread_join (pthread_t threadid, void **thread_return)
      un-wait-ed for again.  */
   pthread_cleanup_push (cleanup, &pd->joinid);
 
-  /* Switch to asynchronous cancellation.  */
-  int oldtype = CANCEL_ASYNC ();
-
   if ((pd == self
        || (self->joinid == pd
 	   && (pd->cancelhandling
-	       & (CANCELING_BITMASK | CANCELED_BITMASK | EXITING_BITMASK
+	       & (CANCELED_BITMASK | EXITING_BITMASK
 		  | TERMINATED_BITMASK)) == 0))
       && !CANCEL_ENABLED_AND_CANCELED (self->cancelhandling))
     /* This is a deadlock situation.  The threads are waiting for each
@@ -89,10 +86,6 @@  pthread_join (pthread_t threadid, void **thread_return)
     /* Wait for the child.  */
     lll_wait_tid (pd->tid);
 
-
-  /* Restore cancellation mode.  */
-  CANCEL_RESET (oldtype);
-
   /* Remove the handler.  */
   pthread_cleanup_pop (0);
 
diff --git a/nptl/pthread_timedjoin.c b/nptl/pthread_timedjoin.c
index 3a12bbf..df2a2ee 100644
--- a/nptl/pthread_timedjoin.c
+++ b/nptl/pthread_timedjoin.c
@@ -71,17 +71,9 @@  pthread_timedjoin_np (pthread_t threadid, void **thread_return,
      un-wait-ed for again.  */
   pthread_cleanup_push (cleanup, &pd->joinid);
 
-  /* Switch to asynchronous cancellation.  */
-  int oldtype = CANCEL_ASYNC ();
-
-
   /* Wait for the child.  */
   result = lll_timedwait_tid (pd->tid, abstime);
 
-
-  /* Restore cancellation mode.  */
-  CANCEL_RESET (oldtype);
-
   /* Remove the handler.  */
   pthread_cleanup_pop (0);
 
diff --git a/nptl/sem_timedwait.c b/nptl/sem_timedwait.c
index 7dfe51d..5fae92f 100644
--- a/nptl/sem_timedwait.c
+++ b/nptl/sem_timedwait.c
@@ -29,22 +29,6 @@ 
 
 extern void __sem_wait_cleanup (void *arg) attribute_hidden;
 
-/* This is in a seperate function in order to make sure gcc
-   puts the call site into an exception region, and thus the
-   cleanups get properly run.  */
-static int
-__attribute__ ((noinline))
-do_futex_timed_wait (struct new_sem *isem, struct timespec *rt)
-{
-  int err, oldtype = __pthread_enable_asynccancel ();
-
-  err = lll_futex_timed_wait (&isem->value, 0, rt,
-			      isem->private ^ FUTEX_PRIVATE_FLAG);
-
-  __pthread_disable_asynccancel (oldtype);
-  return err;
-}
-
 int
 sem_timedwait (sem_t *sem, const struct timespec *abstime)
 {
@@ -93,7 +77,8 @@  sem_timedwait (sem_t *sem, const struct timespec *abstime)
       /* Do wait.  */
       rt.tv_sec = sec;
       rt.tv_nsec = nsec;
-      err = do_futex_timed_wait(isem, &rt);
+      err = lll_futex_timed_wait_cancel (&isem->value, 0, &rt,
+				         isem->private ^ FUTEX_PRIVATE_FLAG);
       if (err != 0 && err != -EWOULDBLOCK)
 	{
 	  __set_errno (-err);
diff --git a/nptl/sem_wait.c b/nptl/sem_wait.c
index b12babb..7f995c9 100644
--- a/nptl/sem_wait.c
+++ b/nptl/sem_wait.c
@@ -37,21 +37,6 @@  __sem_wait_cleanup (void *arg)
   atomic_decrement (&isem->nwaiters);
 }
 
-/* This is in a seperate function in order to make sure gcc
-   puts the call site into an exception region, and thus the
-   cleanups get properly run.  */
-static int
-__attribute__ ((noinline))
-do_futex_wait (struct new_sem *isem)
-{
-  int err, oldtype = __pthread_enable_asynccancel ();
-
-  err = lll_futex_wait (&isem->value, 0, isem->private ^ FUTEX_PRIVATE_FLAG);
-
-  __pthread_disable_asynccancel (oldtype);
-  return err;
-}
-
 int
 __new_sem_wait (sem_t *sem)
 {
@@ -67,7 +52,8 @@  __new_sem_wait (sem_t *sem)
 
   while (1)
     {
-      err = do_futex_wait(isem);
+      err = lll_futex_wait_cancel (&isem->value, 0,
+				   isem->private ^ FUTEX_PRIVATE_FLAG);
       if (err != 0 && err != -EWOULDBLOCK)
 	{
 	  __set_errno (-err);
@@ -104,14 +90,8 @@  __old_sem_wait (sem_t *sem)
       if (atomic_decrement_if_positive (futex) > 0)
 	return 0;
 
-      /* Enable asynchronous cancellation.  Required by the standard.  */
-      int oldtype = __pthread_enable_asynccancel ();
-
       /* Always assume the semaphore is shared.  */
-      err = lll_futex_wait (futex, 0, LLL_SHARED);
-
-      /* Disable asynchronous cancellation.  */
-      __pthread_disable_asynccancel (oldtype);
+      err = lll_futex_wait_cancel (futex, 0, LLL_SHARED);
     }
   while (err == 0 || err == -EWOULDBLOCK);
 
diff --git a/rt/Makefile b/rt/Makefile
index 875deb3..c9af7d8 100644
--- a/rt/Makefile
+++ b/rt/Makefile
@@ -62,7 +62,6 @@  include ../Rules
 
 CFLAGS-aio_suspend.c = -fexceptions
 CFLAGS-clock_nanosleep.c = -fexceptions -fasynchronous-unwind-tables
-CFLAGS-librt-cancellation.c = -fasynchronous-unwind-tables
 
 LDFLAGS-rt.so = -Wl,--enable-new-dtags,-z,nodelete
 
diff --git a/sysdeps/generic/sysdep-cancel.h b/sysdeps/generic/sysdep-cancel.h
index ba6a1e0..5c84b44 100644
--- a/sysdeps/generic/sysdep-cancel.h
+++ b/sysdeps/generic/sysdep-cancel.h
@@ -3,6 +3,3 @@ 
 /* No multi-thread handling enabled.  */
 #define SINGLE_THREAD_P (1)
 #define RTLD_SINGLE_THREAD_P (1)
-#define LIBC_CANCEL_ASYNC()	0 /* Just a dummy value.  */
-#define LIBC_CANCEL_RESET(val)	((void)(val)) /* Nothing, but evaluate it.  */
-#define LIBC_CANCEL_HANDLED()	/* Nothing.  */
diff --git a/sysdeps/nptl/Makefile b/sysdeps/nptl/Makefile
index bedf39b..3cdf2fd 100644
--- a/sysdeps/nptl/Makefile
+++ b/sysdeps/nptl/Makefile
@@ -21,8 +21,7 @@  libpthread-sysdep_routines += errno-loc
 endif
 
 ifeq ($(subdir),rt)
-librt-sysdep_routines += timer_routines librt-cancellation
-CFLAGS-librt-cancellation.c += -fexceptions -fasynchronous-unwind-tables
+librt-sysdep_routines += timer_routines
 
 ifeq ($(have-forced-unwind),yes)
 tests += tst-mqueue8x
diff --git a/sysdeps/nptl/aio_misc.h b/sysdeps/nptl/aio_misc.h
index c3de84b..e34c548 100644
--- a/sysdeps/nptl/aio_misc.h
+++ b/sysdeps/nptl/aio_misc.h
@@ -41,15 +41,15 @@ 
       {									      \
 	pthread_mutex_unlock (&__aio_requests_mutex);			      \
 									      \
-	int oldtype;							      \
-	if (cancel)							      \
-	  oldtype = LIBC_CANCEL_ASYNC ();				      \
-									      \
 	int status;							      \
 	do								      \
 	  {								      \
-	    status = lll_futex_timed_wait (futexaddr, oldval, timeout,	      \
-					   LLL_PRIVATE);		      \
+	    if (cancel)							      \
+	      status = lll_futex_timed_wait_cancel (futexaddr, oldval,	      \
+						    timeout, LLL_PRIVATE);    \
+	    else							      \
+	      status = lll_futex_timed_wait (futexaddr, oldval, timeout,      \
+					     LLL_PRIVATE);		      \
 	    if (status != -EWOULDBLOCK)					      \
 	      break;							      \
 									      \
@@ -57,9 +57,6 @@ 
 	  }								      \
 	while (oldval != 0);						      \
 									      \
-	if (cancel)							      \
-	  LIBC_CANCEL_RESET (oldtype);					      \
-									      \
 	if (status == -EINTR)						      \
 	  result = EINTR;						      \
 	else if (status == -ETIMEDOUT)					      \
diff --git a/sysdeps/nptl/gai_misc.h b/sysdeps/nptl/gai_misc.h
index 942f2b1..40301aa 100644
--- a/sysdeps/nptl/gai_misc.h
+++ b/sysdeps/nptl/gai_misc.h
@@ -42,15 +42,15 @@ 
       {									      \
 	pthread_mutex_unlock (&__gai_requests_mutex);			      \
 									      \
-	int oldtype;							      \
-	if (cancel)							      \
-	  oldtype = LIBC_CANCEL_ASYNC ();				      \
-									      \
 	int status;							      \
 	do								      \
 	  {								      \
-	    status = lll_futex_timed_wait (futexaddr, oldval, timeout,	      \
-					   LLL_PRIVATE);		      \
+	    if (cancel)							      \
+	      status = lll_futex_timed_wait_cancel (futexaddr, oldval,	      \
+						    timeout, LLL_PRIVATE);    \
+	    else							      \
+	      status = lll_futex_timed_wait (futexaddr, oldval, timeout,      \
+					     LLL_PRIVATE);		      \
 	    if (status != -EWOULDBLOCK)					      \
 	      break;							      \
 									      \
@@ -58,9 +58,6 @@ 
 	  }								      \
 	while (oldval != 0);						      \
 									      \
-	if (cancel)							      \
-	  LIBC_CANCEL_RESET (oldtype);					      \
-									      \
 	if (status == -EINTR)						      \
 	  result = EINTR;						      \
 	else if (status == -ETIMEDOUT)					      \
diff --git a/sysdeps/nptl/librt-cancellation.c b/sysdeps/nptl/librt-cancellation.c
deleted file mode 100644
index c0258ba..0000000
--- a/sysdeps/nptl/librt-cancellation.c
+++ /dev/null
@@ -1,24 +0,0 @@ 
-/* Copyright (C) 2002-2014 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
-
-   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 <nptl/pthreadP.h>
-
-
-#define __pthread_enable_asynccancel __librt_enable_asynccancel
-#define __pthread_disable_asynccancel __librt_disable_asynccancel
-#include <nptl/cancellation.c>
diff --git a/sysdeps/nptl/lowlevellock.h b/sysdeps/nptl/lowlevellock.h
index 28f4ba3..abfd528 100644
--- a/sysdeps/nptl/lowlevellock.h
+++ b/sysdeps/nptl/lowlevellock.h
@@ -172,7 +172,7 @@  extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *,
   do {					\
     __typeof (tid) __tid;		\
     while ((__tid = (tid)) != 0)	\
-      lll_futex_wait (&(tid), __tid, LLL_SHARED);\
+      lll_futex_wait_cancel (&(tid), __tid, LLL_SHARED);\
   } while (0)
 
 extern int __lll_timedwait_tid (int *, const struct timespec *)
diff --git a/sysdeps/posix/sigpause.c b/sysdeps/posix/sigpause.c
index 3dcf86c..6210861 100644
--- a/sysdeps/posix/sigpause.c
+++ b/sysdeps/posix/sigpause.c
@@ -50,16 +50,7 @@  do_sigpause (int sig_or_mask, int is_sig)
 int
 __sigpause (int sig_or_mask, int is_sig)
 {
-  if (SINGLE_THREAD_P)
-    return do_sigpause (sig_or_mask, is_sig);
-
-  int oldtype = LIBC_CANCEL_ASYNC ();
-
-  int result = do_sigpause (sig_or_mask, is_sig);
-
-  LIBC_CANCEL_RESET (oldtype);
-
-  return result;
+  return do_sigpause (sig_or_mask, is_sig);
 }
 libc_hidden_def (__sigpause)
 
diff --git a/sysdeps/posix/waitid.c b/sysdeps/posix/waitid.c
index d8c3e15..93eeb62 100644
--- a/sysdeps/posix/waitid.c
+++ b/sysdeps/posix/waitid.c
@@ -151,16 +151,7 @@  OUR_WAITID (idtype_t idtype, id_t id, siginfo_t *infop, int options)
 int
 __waitid (idtype_t idtype, id_t id, siginfo_t *infop, int options)
 {
-  if (SINGLE_THREAD_P)
-    return do_waitid (idtype, id, infop, options);
-
-  int oldtype = LIBC_CANCEL_ASYNC ();
-
-  int result = do_waitid (idtype, id, infop, options);
-
-  LIBC_CANCEL_RESET (oldtype);
-
-  return result;
+  return do_waitid (idtype, id, infop, options);
 }
 weak_alias (__waitid, waitid)
 strong_alias (__waitid, __libc_waitid)
diff --git a/sysdeps/powerpc/nptl/pthreaddef.h b/sysdeps/powerpc/nptl/pthreaddef.h
index 5c6a0cd..5fe1cdb 100644
--- a/sysdeps/powerpc/nptl/pthreaddef.h
+++ b/sysdeps/powerpc/nptl/pthreaddef.h
@@ -15,6 +15,9 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
+#ifndef _PTHREADDEF_H
+# define _PTHREADDEF_H
+
 /* Default stack size.  */
 #define ARCH_STACK_DEFAULT_SIZE	(4 * 1024 * 1024)
 
@@ -31,3 +34,11 @@ 
 
 /* Location of current stack frame.  */
 #define CURRENT_STACK_FRAME	__builtin_frame_address (0)
+
+static inline
+const char * __pthread_get_ip (const ucontext_t *uc)
+{
+  return (char *)uc->uc_mcontext.gp_regs[PT_NIP];
+}
+
+#endif
diff --git a/sysdeps/unix/sysdep.h b/sysdeps/unix/sysdep.h
index 6367742..e14b55f 100644
--- a/sysdeps/unix/sysdep.h
+++ b/sysdeps/unix/sysdep.h
@@ -20,31 +20,69 @@ 
 #include <sys/syscall.h>
 #define	HAVE_SYSCALLS
 
+#ifndef __ASSEMBLER__
+# include <errno.h>
+
 /* Note that using a `PASTE' macro loses.  */
 #define	SYSCALL__(name, args)	PSEUDO (__##name, name, args)
 #define	SYSCALL(name, args)	PSEUDO (name, name, args)
 
 /* Cancellation macros.  */
-#define __SYSCALL_NARGS_X(a,b,c,d,e,f,g,n,...) n
+#ifndef __SSC
+typedef long __syscall_arg_t;
+# define __SSC(__x) ((__syscall_arg_t) (__x))
+#endif
+
+#define __SYSCALL_CANCEL0(__n) \
+  (__syscall_cancel)(__n, 0, 0, 0, 0, 0, 0)
+#define __SYSCALL_CANCEL1(__n, __a) \
+  (__syscall_cancel)(__n, __SSC(__a), 0, 0, 0, 0, 0)
+#define __SYSCALL_CANCEL2(__n, __a, __b) \
+  (__syscall_cancel)(__n, __SSC(__a), __SSC(__b), 0, 0, 0, 0)
+#define __SYSCALL_CANCEL3(__n, __a, __b, __c) \
+  (__syscall_cancel)(__n, __SSC(__a), __SSC(__b), __SSC(__c), 0, 0, 0)
+#define __SYSCALL_CANCEL4(__n, __a, __b, __c, __d) \
+  (__syscall_cancel)(__n, __SSC(__a), __SSC(__b), __SSC(__c), __SSC(__d), \
+		     0, 0)
+#define __SYSCALL_CANCEL5(__n, __a, __b, __c, __d, __e) \
+  (__syscall_cancel)(__n, __SSC(__a), __SSC(__b), __SSC(__c), __SSC(__d), \
+		     __SSC(__e), 0)
+#define __SYSCALL_CANCEL6(__n, __a, __b, __c, __d, __e, __f) \
+  (__syscall_cancel)(__n, __SSC(__a), __SSC(__b), __SSC(__c), __SSC(__d), \
+		     __SSC(__e), __SSC(__f))
+
+#define __SYSCALL_NARGS_X(a,b,c,d,e,f,g,h,n,...) n
 #define __SYSCALL_NARGS(...) \
   __SYSCALL_NARGS_X (__VA_ARGS__, 7, 6, 5, 4, 3, 2, 1, 0,)
+#define __SYSCALL_CONCAT_X(__a,__b)	__a##__b
+#define __SYSCALL_CONCAT(__a,__b)	__SYSCALL_CONCAT_X (__a, __b)
+#define __SYSCALL_DISP(__b,...) \
+  __SYSCALL_CONCAT (__b,__SYSCALL_NARGS(__VA_ARGS__))(__VA_ARGS__)
+
+#define __SYSCALL_CANCEL(...) __SYSCALL_DISP (__SYSCALL_CANCEL, __VA_ARGS__)
 
-#define SYSCALL_CANCEL(name, ...) \
-  ({									     \
-    long int sc_ret;							     \
-    if (SINGLE_THREAD_P) 						     \
-      sc_ret = INLINE_SYSCALL (name, __SYSCALL_NARGS(__VA_ARGS__),	     \
-			       __VA_ARGS__);				     \
-    else								     \
-      {									     \
-	int sc_cancel_oldtype = LIBC_CANCEL_ASYNC ();			     \
-	sc_ret = INLINE_SYSCALL (name, __SYSCALL_NARGS (__VA_ARGS__),	     \
-				 __VA_ARGS__);				     \
-        LIBC_CANCEL_RESET (sc_cancel_oldtype);				     \
-      }									     \
-    sc_ret;								     \
+#define SYSCALL_CANCEL_NCS(name, nr, args...)				\
+  __SYSCALL_CANCEL (__NR_##name, nr, args)
+
+#define SYSCALL_CANCEL(name, args...)					\
+  ({									\
+    long int sc_ret = SYSCALL_CANCEL_NCS (name, args);			\
+    if (SYSCALL_CANCEL_ERROR (sc_ret))					\
+      {									\
+        __set_errno (SYSCALL_CANCEL_ERRNO (sc_ret));			\
+        sc_ret = -1L;							\
+      }									\
+    sc_ret;								\
   })
 
+long int __syscall_cancel (__syscall_arg_t nr, __syscall_arg_t arg1,
+			   __syscall_arg_t arg2, __syscall_arg_t arg3,
+			   __syscall_arg_t arg4, __syscall_arg_t arg5,
+			   __syscall_arg_t arg6);
+libc_hidden_proto (__syscall_cancel);
+
+#endif
+
 /* Machine-dependent sysdep.h files are expected to define the macro
    PSEUDO (function_name, syscall_name) to emit assembly code to define the
    C-callable function FUNCTION_NAME to do system call SYSCALL_NAME.
diff --git a/sysdeps/unix/sysv/linux/clock_nanosleep.c b/sysdeps/unix/sysv/linux/clock_nanosleep.c
index 174c0d0..1e83f63 100644
--- a/sysdeps/unix/sysv/linux/clock_nanosleep.c
+++ b/sysdeps/unix/sysv/linux/clock_nanosleep.c
@@ -28,7 +28,6 @@  int
 __clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
 		   struct timespec *rem)
 {
-  INTERNAL_SYSCALL_DECL (err);
   int r;
 
   if (clock_id == CLOCK_THREAD_CPUTIME_ID)
@@ -36,19 +35,9 @@  __clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
   if (clock_id == CLOCK_PROCESS_CPUTIME_ID)
     clock_id = MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED);
 
-  if (SINGLE_THREAD_P)
-    r = INTERNAL_SYSCALL (clock_nanosleep, err, 4, clock_id, flags, req, rem);
-  else
-    {
-      int oldstate = LIBC_CANCEL_ASYNC ();
+  r = SYSCALL_CANCEL_NCS (clock_nanosleep, clock_id, flags, req, rem);
 
-      r = INTERNAL_SYSCALL (clock_nanosleep, err, 4, clock_id, flags, req,
-			    rem);
-
-      LIBC_CANCEL_RESET (oldstate);
-    }
-
-  return (INTERNAL_SYSCALL_ERROR_P (r, err)
-	  ? INTERNAL_SYSCALL_ERRNO (r, err) : 0);
+  return (SYSCALL_CANCEL_ERROR (r)
+	  ? SYSCALL_CANCEL_ERRNO (r) : 0);
 }
 weak_alias (__clock_nanosleep, clock_nanosleep)
diff --git a/sysdeps/unix/sysv/linux/lowlevellock-futex.h b/sysdeps/unix/sysv/linux/lowlevellock-futex.h
index 343afd6..f0eb9fa 100644
--- a/sysdeps/unix/sysv/linux/lowlevellock-futex.h
+++ b/sysdeps/unix/sysv/linux/lowlevellock-futex.h
@@ -133,5 +133,50 @@ 
 					 private),                      \
 		     nr_wake, nr_move, mutex, val)
 
+/* Cancellable futex macros.  */
+#define lll_futex_wait_cancel(futexp, val, private) \
+  lll_futex_timed_wait_cancel (futexp, val, NULL, private)
+
+#define lll_futex_timed_wait_cancel(futexp, val, timespec, private)	      \
+  ({									      \
+    long int __ret;							      \
+    int __op = FUTEX_WAIT;						      \
+                                                                              \
+    __ret = __syscall_cancel (__NR_futex, __SSC (futexp),		      \
+			      __SSC (__lll_private_flag (__op, private)),     \
+			      __SSC (val), __SSC (timespec), 0, 0);           \
+    __ret;								      \
+  })
+
+#define lll_futex_timed_wait_bitset_cancel(futexp, val, timespec, clockbit,   \
+					   private)			      \
+  ({                                                                          \
+    long int __ret;                                                           \
+    int __op = FUTEX_WAIT_BITSET | clockbit;                                  \
+                                                                              \
+    __ret = __syscall_cancel (__NR_futex, __SSC (futexp),		      \
+			      __SSC (__lll_private_flag (__op, private)),     \
+			      __SSC (val), __SSC (timespec), 0,	              \
+                              FUTEX_BITSET_MATCH_ANY);                        \
+    __ret;								      \
+  })
+
+#define lll_futex_wait_requeue_pi_cancel(futexp, val, mutex, private) \
+  lll_futex_timed_wait_requeue_pi_cancel (futexp, val, NULL, 0, mutex, private)
+
+#define lll_futex_timed_wait_requeue_pi_cancel(futexp, val, timespec, 	      \
+					       clockbit, mutex, private)      \
+  ({									      \
+    long int __ret;							      \
+    int __op = FUTEX_WAIT_REQUEUE_PI | clockbit;			      \
+									      \
+    __ret = __syscall_cancel (__NR_futex, __SSC (futexp),		      \
+			      __SSC (__lll_private_flag (__op, private)),     \
+			      __SSC (val), __SSC (timespec),		      \
+			      __SSC (mutex), 0); 		      	      \
+    __ret;								      \
+  })
+
+
 
 #endif  /* lowlevellock-futex.h */
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/fcntl.c b/sysdeps/unix/sysv/linux/powerpc/powerpc64/fcntl.c
index ee31a1b..ad1169b 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/fcntl.c
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/fcntl.c
@@ -23,8 +23,7 @@ 
 
 #include <sys/syscall.h>
 
-
-#ifndef NO_CANCELLATION
+#ifndef IS_IN_rtld
 int
 __fcntl_nocancel (int fd, int cmd, ...)
 {
@@ -39,7 +38,6 @@  __fcntl_nocancel (int fd, int cmd, ...)
 }
 #endif
 
-
 int
 __libc_fcntl (int fd, int cmd, ...)
 {
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/socket.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/socket.S
index 2a253e1..f41a179 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/socket.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/socket.S
@@ -48,10 +48,10 @@ 
 
 #if _CALL_ELF == 2
 #define FRAMESIZE (FRAME_MIN_SIZE+16+64)
-#define stackblock (FRAME_MIN_SIZE+16)
+#define STACKBLOCK (FRAME_MIN_SIZE+16)
 #else
 #define FRAMESIZE (FRAME_MIN_SIZE+16)
-#define stackblock (FRAMESIZE+FRAME_PARM_SAVE) /* offset to parm save area.  */
+#define STACKBLOCK (FRAMESIZE+FRAME_PARM_SAVE) /* offset to parm save area.  */
 #endif
 
 	.text
@@ -59,75 +59,69 @@  ENTRY(__socket)
 	CALL_MCOUNT NARGS
 	stdu r1,-FRAMESIZE(r1)
 	cfi_adjust_cfa_offset(FRAMESIZE)
+
 #if NARGS >= 1
-	std  r3,stackblock(r1)
+	std  r3,STACKBLOCK(r1)
 #endif
 #if NARGS >= 2
-	std  r4,8+stackblock(r1)
+	std  r4,8+STACKBLOCK(r1)
 #endif
 #if NARGS >= 3
-	std  r5,16+stackblock(r1)
+	std  r5,16+STACKBLOCK(r1)
 #endif
 #if NARGS >= 4
-	std  r6,24+stackblock(r1)
+	std  r6,24+STACKBLOCK(r1)
 #endif
 #if NARGS >= 5
-	std  r7,32+stackblock(r1)
+	std  r7,32+STACKBLOCK(r1)
 #endif
 #if NARGS >= 6
-	std  r8,40+stackblock(r1)
+	std  r8,40+STACKBLOCK(r1)
 #endif
 #if NARGS >= 7
-	std  r9,48+stackblock(r1)
+	std  r9,48+STACKBLOCK(r1)
 #endif
 #if NARGS >= 8
-	std  r10,56+stackblock(r1)
+	std  r10,56+STACKBLOCK(r1)
 #endif
 #if NARGS >= 9
 #error too many arguments!
 #endif
 
-#if defined NEED_CANCELLATION && defined CENABLE
+#ifdef NEED_CANCELLATION
 	SINGLE_THREAD_P
-	bne-	.Lsocket_cancel
+	bne-	L(socket_cancel)
 #endif
 
-	li	r3,P(SOCKOP_,socket)
-	addi	r4,r1,stackblock
-	DO_CALL(SYS_ify(socketcall))
-	addi	r1,r1,FRAMESIZE
+#ifndef NEED_CANCELLATION
+        li      r3,P(SOCKOP_,socket)
+        addi    r4,r1,STACKBLOCK
+        DO_CALL(SYS_ify(socketcall))
+	addi    r1,r1,FRAMESIZE
 	cfi_adjust_cfa_offset(-FRAMESIZE)
-	PSEUDO_RET
-
-#if defined NEED_CANCELLATION && defined CENABLE
-.Lsocket_cancel:
-	cfi_adjust_cfa_offset(FRAMESIZE)
+	bnslr+
+	TAIL_CALL_SYSCALL_ERROR
+#else
+L(socket_cancel):
 	mflr	r9
 	std	r9,FRAMESIZE+FRAME_LR_SAVE(r1)
-	cfi_offset (lr, FRAME_LR_SAVE)
-	CENABLE
-	std	r3,FRAME_MIN_SIZE+8(r1)
-	li	r3,P(SOCKOP_,socket)
-	addi	r4,r1,stackblock
-	DO_CALL(SYS_ify(socketcall))
-	mfcr	r0
-	std	r3,FRAME_MIN_SIZE(r1)
-	std	r0,FRAMESIZE+FRAME_CR_SAVE(r1)
-	cfi_offset (cr, FRAME_CR_SAVE)
-	ld  	r3,FRAME_MIN_SIZE+8(r1)
-	CDISABLE
-	ld	r4,FRAMESIZE+FRAME_LR_SAVE(r1)
-	ld	r0,FRAMESIZE+FRAME_CR_SAVE(r1)
-	ld	r3,FRAME_MIN_SIZE(r1)
-	mtlr	r4
-	mtcr	r0
+	cfi_offset(lr, FRAME_LR_SAVE);
+
+	li	r3,SYS_ify (socketcall)
+	li	r4,P(SOCKOP_,socket)
+	addi	r5,r1,STACKBLOCK
+	bl	HIDDEN_JUMPTARGET(__syscall_cancel)
+	nop
+	bl	JUMPTARGET(__syscall_cancel_error)
+	nop
+	ld	r9,FRAMESIZE+FRAME_LR_SAVE(r1)
+	mtlr	r9
+	cfi_restore(lr)
 	addi	r1,r1,FRAMESIZE
 	cfi_adjust_cfa_offset(-FRAMESIZE)
-	cfi_restore(lr)
-	cfi_restore(cr)
-	PSEUDO_RET
-#endif
-PSEUDO_END (__socket)
+	blr
+#endif /* NEED_CANCELLATION  */
+END (__socket)
 
 #ifndef NO_WEAK_ALIAS
 weak_alias (__socket, socket)
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep-cancel.h b/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep-cancel.h
index 5807d9d..b78d64b 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep-cancel.h
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep-cancel.h
@@ -31,117 +31,59 @@ 
 #  define DASHDASHPFX(str) __##str
 # endif
 
-#if _CALL_ELF == 2
-#define CANCEL_FRAMESIZE (FRAME_MIN_SIZE+16+48)
-#define CANCEL_PARM_SAVE (FRAME_MIN_SIZE+16)
-#else
-#define CANCEL_FRAMESIZE (FRAME_MIN_SIZE+16)
-#define CANCEL_PARM_SAVE (CANCEL_FRAMESIZE+FRAME_PARM_SAVE)
-#endif
+# ifdef NOT_IN_libc
+#  undef HIDDEN_JUMPTARGET
+#  define HIDDEN_JUMPTARGET(__symbol) __symbol
+# endif
+
+#define CANCEL_FRAMESIZE (FRAME_MIN_SIZE)
 
 # undef PSEUDO
 # define PSEUDO(name, syscall_name, args)				\
   .section ".text";							\
   ENTRY (name)								\
     SINGLE_THREAD_P;							\
-    bne- .Lpseudo_cancel;						\
-  .type DASHDASHPFX(syscall_name##_nocancel),@function;			\
-  .globl DASHDASHPFX(syscall_name##_nocancel);				\
-  DASHDASHPFX(syscall_name##_nocancel):					\
+    bne- L(pseudo_cancel);						\
     DO_CALL (SYS_ify (syscall_name));					\
-    PSEUDO_RET;								\
-  .size DASHDASHPFX(syscall_name##_nocancel),.-DASHDASHPFX(syscall_name##_nocancel);	\
-  .Lpseudo_cancel:							\
-    stdu 1,-CANCEL_FRAMESIZE(1);					\
-    cfi_adjust_cfa_offset (CANCEL_FRAMESIZE);				\
-    mflr 9;								\
-    std  9,CANCEL_FRAMESIZE+FRAME_LR_SAVE(1);				\
+    bnslr+;								\
+    TAIL_CALL_SYSCALL_ERROR;						\
+  L(pseudo_cancel):							\
+    mflr r0;								\
+    std  r0,FRAME_LR_SAVE(r1);						\
     cfi_offset (lr, FRAME_LR_SAVE);					\
-    DOCARGS_##args;	/* save syscall args around CENABLE.  */	\
-    CENABLE;								\
-    std  3,FRAME_MIN_SIZE(1); /* store CENABLE return value (MASK).  */	\
-    UNDOCARGS_##args;	/* restore syscall args.  */			\
-    DO_CALL (SYS_ify (syscall_name));					\
-    mfcr 0;		/* save CR/R3 around CDISABLE.  */		\
-    std  3,FRAME_MIN_SIZE+8(1);						\
-    std  0,CANCEL_FRAMESIZE+FRAME_CR_SAVE(1);				\
-    cfi_offset (cr, FRAME_CR_SAVE);					\
-    ld   3,FRAME_MIN_SIZE(1); /* pass MASK to CDISABLE.  */		\
-    CDISABLE;								\
-    ld   9,CANCEL_FRAMESIZE+FRAME_LR_SAVE(1);				\
-    ld   0,CANCEL_FRAMESIZE+FRAME_CR_SAVE(1); /* restore CR/R3. */	\
-    ld   3,FRAME_MIN_SIZE+8(1);						\
-    mtlr 9;								\
-    mtcr 0;								\
-    addi 1,1,CANCEL_FRAMESIZE;						\
+    stdu r1,-CANCEL_FRAMESIZE(r1);					\
+    cfi_adjust_cfa_offset (CANCEL_FRAMESIZE);				\
+    mr   r9,r8;								\
+    mr   r8,r7;								\
+    mr   r7,r6;								\
+    mr   r6,r5;								\
+    mr   r5,r4;								\
+    mr   r4,r3;								\
+    li   r3,SYS_ify (syscall_name);					\
+    bl   HIDDEN_JUMPTARGET(__syscall_cancel);				\
+    nop;								\
+    bl   JUMPTARGET(__syscall_cancel_error);				\
+    nop;								\
+    addi r1,r1,CANCEL_FRAMESIZE;					\
     cfi_adjust_cfa_offset (-CANCEL_FRAMESIZE);				\
+    ld   r0,FRAME_LR_SAVE(r1);						\
+    mtlr r0;								\
     cfi_restore (lr);							\
-    cfi_restore (cr)
-
-# define DOCARGS_0
-# define UNDOCARGS_0
-
-# define DOCARGS_1	std 3,CANCEL_PARM_SAVE(1); DOCARGS_0
-# define UNDOCARGS_1	ld 3,CANCEL_PARM_SAVE(1); UNDOCARGS_0
-
-# define DOCARGS_2	std 4,CANCEL_PARM_SAVE+8(1); DOCARGS_1
-# define UNDOCARGS_2	ld 4,CANCEL_PARM_SAVE+8(1); UNDOCARGS_1
+    blr
 
-# define DOCARGS_3	std 5,CANCEL_PARM_SAVE+16(1); DOCARGS_2
-# define UNDOCARGS_3	ld 5,CANCEL_PARM_SAVE+16(1); UNDOCARGS_2
-
-# define DOCARGS_4	std 6,CANCEL_PARM_SAVE+24(1); DOCARGS_3
-# define UNDOCARGS_4	ld 6,CANCEL_PARM_SAVE+24(1); UNDOCARGS_3
-
-# define DOCARGS_5	std 7,CANCEL_PARM_SAVE+32(1); DOCARGS_4
-# define UNDOCARGS_5	ld 7,CANCEL_PARM_SAVE+32(1); UNDOCARGS_4
-
-# define DOCARGS_6	std 8,CANCEL_PARM_SAVE+40(1); DOCARGS_5
-# define UNDOCARGS_6	ld 8,CANCEL_PARM_SAVE+40(1); UNDOCARGS_5
-
-# ifdef IS_IN_libpthread
-#  ifdef SHARED
-#   define CENABLE	bl JUMPTARGET(__pthread_enable_asynccancel)
-#   define CDISABLE	bl JUMPTARGET(__pthread_disable_asynccancel)
-#  else
-#   define CENABLE	bl JUMPTARGET(__pthread_enable_asynccancel); nop
-#   define CDISABLE	bl JUMPTARGET(__pthread_disable_asynccancel); nop
-#  endif
-# elif !defined NOT_IN_libc
-#  ifdef SHARED
-#   define CENABLE	bl JUMPTARGET(__libc_enable_asynccancel)
-#   define CDISABLE	bl JUMPTARGET(__libc_disable_asynccancel)
-#  else
-#   define CENABLE	bl JUMPTARGET(__libc_enable_asynccancel); nop
-#   define CDISABLE	bl JUMPTARGET(__libc_disable_asynccancel); nop
-#  endif
-# elif defined IS_IN_librt
-#  ifdef SHARED
-#   define CENABLE	bl JUMPTARGET(__librt_enable_asynccancel)
-#   define CDISABLE	bl JUMPTARGET(__librt_disable_asynccancel)
-#  else
-#   define CENABLE	bl JUMPTARGET(__librt_enable_asynccancel); nop
-#   define CDISABLE	bl JUMPTARGET(__librt_disable_asynccancel); nop
-#  endif
-# else
-#  error Unsupported library
-# endif
+# undef PSEUDO_RET
+# define PSEUDO_RET
 
 # ifndef __ASSEMBLER__
-#  define SINGLE_THREAD_P						\
-  __builtin_expect (THREAD_GETMEM (THREAD_SELF,				\
-				   header.multiple_threads) == 0, 1)
+#  define SINGLE_THREAD_P                                               \
+  __builtin_expect (THREAD_GETMEM (THREAD_SELF,                         \
+                                   header.multiple_threads) == 0, 1)
 # else
-#   define SINGLE_THREAD_P						\
-  lwz   10,MULTIPLE_THREADS_OFFSET(13);				\
+#   define SINGLE_THREAD_P                                              \
+  lwz   10,MULTIPLE_THREADS_OFFSET(13);                         	\
   cmpwi 10,0
 # endif
 
-#elif !defined __ASSEMBLER__
-
-# define SINGLE_THREAD_P (1)
-# define NO_CANCELLATION 1
-
 #endif
 
 #ifndef __ASSEMBLER__
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h b/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h
index 93e454e..4922752 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h
@@ -184,6 +184,15 @@ 
     sc_ret;								\
   })
 
+#undef SYSCALL_CANCEL_ERROR
+#define SYSCALL_CANCEL_ERROR(err)					\
+  (err > 0xfffffffffffff000UL)
+
+#undef SYSCALL_CANCEL_ERRNO
+#define SYSCALL_CANCEL_ERRNO(err)					\
+  (-err)
+
+
 /* Define a macro which expands inline into the wrapper code for a system
    call. This use is for internal calls that do not need to handle errors
    normally. It will never touch errno. This returns just what the kernel
diff --git a/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S b/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S
new file mode 100644
index 0000000..4d9e5b5
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S
@@ -0,0 +1,56 @@ 
+/* Cancellable syscall wrapper - powerpc version.
+   Copyright (C) 2014 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 <sysdep.h>
+
+ENTRY (__syscall_cancel_arch)
+
+	.globl __syscall_cancel_arch_start
+	.type  __syscall_cancel_arch_start,@function
+__syscall_cancel_arch_start:
+
+	/*mflr	r10
+	std	r10,FRAME_LR_SAVE(r1)*/
+
+	lwz     r0,0(r3)
+	rldicl. r0,r0,62,63
+	beq     1f
+	b       __syscall_do_cancel
+	nop
+1:
+	mr      r0,r4
+	mr      r3,r5
+	mr      r4,r6
+	mr      r5,r7
+	mr      r6,r8
+	mr      r7,r9
+	mr      r8,r10
+	sc
+
+	.globl __syscall_cancel_arch_end
+	.type  __syscall_cancel_arch_end,@function
+__syscall_cancel_arch_end:
+
+	/*ld	r10,FRAME_LR_SAVE(r1)
+	mtlr	r10*/
+
+	bnslr+
+	neg	r3,r3
+	blr
+END (__syscall_cancel_arch)
+libc_hidden_def (__syscall_cancel_arch)
diff --git a/sysdeps/unix/sysv/linux/powerpc/sysdep.c b/sysdeps/unix/sysv/linux/powerpc/sysdep.c
index 0c11d2b..1684399 100644
--- a/sysdeps/unix/sysv/linux/powerpc/sysdep.c
+++ b/sysdeps/unix/sysv/linux/powerpc/sysdep.c
@@ -26,3 +26,14 @@  __syscall_error (int err_no)
   __set_errno (err_no);
   return -1;
 }
+
+long int
+__syscall_cancel_error (unsigned long err)
+{
+  if (__glibc_unlikely ((err) & (1 << 28)))
+    {
+      __set_errno (-err);
+      return -1;
+    }
+  return err;
+}
diff --git a/sysdeps/unix/sysv/linux/pthread_kill.c b/sysdeps/unix/sysv/linux/pthread_kill.c
index d4af6ac..b929645 100644
--- a/sysdeps/unix/sysv/linux/pthread_kill.c
+++ b/sysdeps/unix/sysv/linux/pthread_kill.c
@@ -41,9 +41,8 @@  __pthread_kill (pthread_t threadid, int signo)
     /* Not a valid thread handle.  */
     return ESRCH;
 
-  /* Disallow sending the signal we use for cancellation, timers,
-     for the setxid implementation.  */
-  if (signo == SIGCANCEL || signo == SIGTIMER || signo == SIGSETXID)
+  /* Disallow sending the signal we use for setxid implementation.  */
+  if (signo == SIGSETXID)
     return EINVAL;
 
   /* We have a special syscall to do the work.  */
diff --git a/sysdeps/unix/sysv/linux/sigwait.c b/sysdeps/unix/sysv/linux/sigwait.c
index 688a078..6063cfc 100644
--- a/sysdeps/unix/sysv/linux/sigwait.c
+++ b/sysdeps/unix/sysv/linux/sigwait.c
@@ -55,32 +55,17 @@  do_sigwait (const sigset_t *set, int *sig)
 
   /* XXX The size argument hopefully will have to be changed to the
      real size of the user-level sigset_t.  */
-#ifdef INTERNAL_SYSCALL
-  INTERNAL_SYSCALL_DECL (err);
   do
-    ret = INTERNAL_SYSCALL (rt_sigtimedwait, err, 4, set,
-			    NULL, NULL, _NSIG / 8);
-  while (INTERNAL_SYSCALL_ERROR_P (ret, err)
-	 && INTERNAL_SYSCALL_ERRNO (ret, err) == EINTR);
-  if (! INTERNAL_SYSCALL_ERROR_P (ret, err))
+    ret = SYSCALL_CANCEL_NCS (rt_sigtimedwait, set, NULL, NULL, _NSIG / 8);
+  while (SYSCALL_CANCEL_ERROR (ret)
+	 && SYSCALL_CANCEL_ERRNO (ret) == EINTR);
+  if (!SYSCALL_CANCEL_ERROR (ret))
     {
       *sig = ret;
       ret = 0;
     }
   else
-    ret = INTERNAL_SYSCALL_ERRNO (ret, err);
-#else
-  do
-    ret = INLINE_SYSCALL (rt_sigtimedwait, 4, set, NULL, NULL, _NSIG / 8);
-  while (ret == -1 && errno == EINTR);
-  if (ret != -1)
-    {
-      *sig = ret;
-      ret = 0;
-    }
-  else
-    ret = errno;
-#endif
+    ret = SYSCALL_CANCEL_ERRNO (ret);
 
   return ret;
 }
@@ -88,16 +73,7 @@  do_sigwait (const sigset_t *set, int *sig)
 int
 __sigwait (const sigset_t *set, int *sig)
 {
-  if (SINGLE_THREAD_P)
-    return do_sigwait (set, sig);
-
-  int oldtype = LIBC_CANCEL_ASYNC ();
-
-  int result = do_sigwait (set, sig);
-
-  LIBC_CANCEL_RESET (oldtype);
-
-  return result;
+  return do_sigwait (set, sig);
 }
 libc_hidden_def (__sigwait)
 weak_alias (__sigwait, sigwait)