diff --git a/lib/libkse/thread/thr_init.c b/lib/libkse/thread/thr_init.c
index be3ad8072756..7f6099458d8c 100644
--- a/lib/libkse/thread/thr_init.c
+++ b/lib/libkse/thread/thr_init.c
@@ -268,9 +268,7 @@ _libpthread_init(struct pthread *curthread)
 	_kse_initial->k_kseg = _kseg_alloc(NULL);
 	if (_kse_initial->k_kseg == NULL)
 		PANIC("Can't allocate initial kseg.");
-#ifdef SYSTEM_SCOPE_ONLY
 	_kse_initial->k_kseg->kg_flags |= KGF_SINGLE_THREAD;
-#endif
 	_kse_initial->k_schedq = &_kse_initial->k_kseg->kg_schedq;
 
 	TAILQ_INSERT_TAIL(&_kse_initial->k_kseg->kg_kseq, _kse_initial, k_kgqe);
@@ -309,6 +307,9 @@ _libpthread_init(struct pthread *curthread)
 	_kcb_set(_thr_initial->kse->k_kcb);
 	_tcb_set(_thr_initial->kse->k_kcb, _thr_initial->tcb);
 	_thr_initial->kse->k_flags |= KF_INITIALIZED;
+
+	_thr_signal_init();
+	_kse_critical_leave(&_thr_initial->tcb->tcb_tmbx);
 }
 
 /*
@@ -322,9 +323,7 @@ init_main_thread(struct pthread *thread)
 
 	/* Setup the thread attributes. */
 	thread->attr = _pthread_attr_default;
-#ifdef SYSTEM_SCOPE_ONLY
 	thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
-#endif
 	/*
 	 * Set up the thread stack.
 	 *
diff --git a/lib/libkse/thread/thr_kern.c b/lib/libkse/thread/thr_kern.c
index ae151d7b9a84..33b4c54b359a 100644
--- a/lib/libkse/thread/thr_kern.c
+++ b/lib/libkse/thread/thr_kern.c
@@ -411,6 +411,9 @@ _kse_setthreaded(int threaded)
 	sigset_t sigset;
 
 	if ((threaded != 0) && (__isthreaded == 0)) {
+		SIGFILLSET(sigset);
+		__sys_sigprocmask(SIG_SETMASK, &sigset, &_thr_initial->sigmask);
+
 		/*
 		 * Tell the kernel to create a KSE for the initial thread
 		 * and enable upcalls in it.
@@ -425,10 +428,11 @@ _kse_setthreaded(int threaded)
 		_tcb_set(_kse_initial->k_kcb, _thr_initial->tcb);
 		KSE_SET_MBOX(_kse_initial, _thr_initial);
 		_kse_initial->k_kcb->kcb_kmbx.km_flags |= KMF_BOUND;
+#else
+		_thr_initial->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
+		_kse_initial->k_kseg->kg_flags &= ~KGF_SINGLE_THREAD;
+		_kse_initial->k_kcb->kcb_kmbx.km_curthread = NULL;
 #endif
-		SIGFILLSET(sigset);
-		__sys_sigprocmask(SIG_SETMASK, &sigset, &_thr_initial->sigmask);
-		_thr_signal_init();
 
 		/*
 		 * Locking functions in libc are required when there are
@@ -963,12 +967,6 @@ kse_sched_multi(struct kse_mailbox *kmbx)
 	 */
 	_tcb_set(curkse->k_kcb, NULL);
 
-	/* This may have returned from a kse_release(). */
-	if (KSE_WAITING(curkse)) {
-		DBG_MSG("Entered upcall when KSE is waiting.");
-		KSE_CLEAR_WAIT(curkse);
-	}
-
 	/* If this is an upcall; take the scheduler lock. */
 	if (curkse->k_switch == 0)
 		KSE_SCHED_LOCK(curkse, curkse->k_kseg);
@@ -1156,16 +1154,16 @@ thr_resume_wrapper(int sig, siginfo_t *siginfo, ucontext_t *ucp)
 {
 	struct pthread *curthread = _get_curthread();
 	struct kse *curkse;
-	int ret, err_save = curthread->error;
+	int ret, err_save = errno;
 
 	DBG_MSG(">>> sig wrapper\n");
 	if (curthread->lock_switch)
 		PANIC("thr_resume_wrapper, lock_switch != 0\n");
 	thr_resume_check(curthread, ucp, NULL);
+	errno = err_save;
 	_kse_critical_enter();
 	curkse = _get_curkse();
 	curthread->tcb->tcb_tmbx.tm_context = *ucp;
-	curthread->error = err_save;
 	ret = _thread_switch(curkse->k_kcb, curthread->tcb, 1);
 	if (ret != 0)
 		PANIC("thr_resume_wrapper: thread has returned "
@@ -2290,11 +2288,7 @@ kse_reinit(struct kse *kse, int sys_scope)
 	kse->k_kseg = 0;
 	kse->k_schedq = 0;
 	kse->k_locklevel = 0;
-	SIGEMPTYSET(kse->k_sigmask);
-	bzero(&kse->k_sigq, sizeof(kse->k_sigq));
-	kse->k_check_sigq = 0;
 	kse->k_flags = 0;
-	kse->k_waiting = 0;
 	kse->k_idle = 0;
 	kse->k_error = 0;
 	kse->k_cpu = 0;
diff --git a/lib/libkse/thread/thr_nanosleep.c b/lib/libkse/thread/thr_nanosleep.c
index 8e709ff3b479..57bbef9e37fc 100644
--- a/lib/libkse/thread/thr_nanosleep.c
+++ b/lib/libkse/thread/thr_nanosleep.c
@@ -55,8 +55,7 @@ _nanosleep(const struct timespec *time_to_sleep,
 		errno = EINVAL;
 		ret = -1;
 	} else {
-		if (!_kse_isthreaded() ||
-		    (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM))
+		if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
 			return (__sys_nanosleep(time_to_sleep, time_remaining));
 			
 		KSE_GET_TOD(curthread->kse, &ts);
diff --git a/lib/libkse/thread/thr_private.h b/lib/libkse/thread/thr_private.h
index 0664aca4b24c..c1ea5928438c 100644
--- a/lib/libkse/thread/thr_private.h
+++ b/lib/libkse/thread/thr_private.h
@@ -188,14 +188,10 @@ struct kse {
 	struct lock		k_lock;
 	struct lockuser		k_lockusers[MAX_KSE_LOCKLEVEL];
 	int			k_locklevel;
-	sigset_t		k_sigmask;
-	struct sigstatus	k_sigq[_SIG_MAXSIG];
 	stack_t			k_stack;
-	int			k_check_sigq;
 	int			k_flags;
 #define	KF_STARTED			0x0001	/* kernel kse created */
 #define	KF_INITIALIZED			0x0002	/* initialized on 1st upcall */
-	int			k_waiting;
 	int			k_idle;		/* kse is idle */
 	int			k_error;	/* syscall errno in critical */
 	int			k_cpu;		/* CPU ID when bound */
@@ -294,11 +290,6 @@ do { \
 #define KSE_WAITQ_INSERT(kse, thrd)	kse_waitq_insert(thrd)
 #define	KSE_WAITQ_FIRST(kse)		TAILQ_FIRST(&(kse)->k_schedq->sq_waitq)
 
-#define	KSE_SET_WAIT(kse) 	atomic_store_rel_int(&(kse)->k_waiting, 1)
-
-#define	KSE_CLEAR_WAIT(kse) 	atomic_store_rel_int(&(kse)->k_waiting, 0)
-
-#define	KSE_WAITING(kse)	(kse)->k_waiting != 0
 #define	KSE_WAKEUP(kse)		kse_wakeup(&(kse)->k_kcb->kcb_kmbx)
 
 #define	KSE_SET_IDLE(kse)	((kse)->k_idle = 1)
@@ -733,9 +724,6 @@ struct pthread {
 	 */
 	int			interrupted;
 
-	/* Signal number when in state PS_SIGWAIT: */
-	int			signo;
-
 	/*
 	 * Set to non-zero when this thread has entered a critical
 	 * region.  We allow for recursive entries into critical regions.
diff --git a/lib/libkse/thread/thr_sig.c b/lib/libkse/thread/thr_sig.c
index 3c6821284be7..01b0914a4374 100644
--- a/lib/libkse/thread/thr_sig.c
+++ b/lib/libkse/thread/thr_sig.c
@@ -310,24 +310,6 @@ _thr_sig_handler(int sig, siginfo_t *info, ucontext_t *ucp)
 
 	DBG_MSG(">>> _thr_sig_handler(%d)\n", sig);
 
-	curkse = _get_curkse();
-	if ((curkse == NULL) || ((curkse->k_flags & KF_STARTED) == 0)) {
-		/* Upcalls are not yet started; just call the handler. */
-		sigfunc = _thread_sigact[sig - 1].sa_sigaction;
-		if (((__sighandler_t *)sigfunc != SIG_DFL) &&
-		    ((__sighandler_t *)sigfunc != SIG_IGN) &&
-		    (sigfunc != (__siginfohandler_t *)_thr_sig_handler)) {
-			if (((_thread_sigact[sig - 1].sa_flags & SA_SIGINFO)
-			    != 0) || (info == NULL))
-				(*(sigfunc))(sig, info, ucp);
-			else
-				(*(sigfunc))(sig,
-				    (siginfo_t*)(intptr_t)info->si_code, ucp);
-		}
-
-		return;
-	}
-
 	curthread = _get_curthread();
 	if (curthread == NULL)
 		PANIC("No current thread.\n");
@@ -359,11 +341,11 @@ _thr_sig_handler(int sig, siginfo_t *info, ucontext_t *ucp)
 	}
 
 	/* It is now safe to invoke signal handler */
-	err_save = curthread->error;
+	err_save = errno;
 	timeout_save = curthread->timeout;
 	intr_save = curthread->interrupted;
-	/* Get a fresh copy of signal mask from kernel, for thread dump only */
-	__sys_sigprocmask(SIG_SETMASK, NULL, &curthread->sigmask);
+	/* Get a fresh copy of signal mask, for thread dump only */
+	curthread->sigmask = ucp->uc_sigmask;
 	_kse_critical_enter();
 	KSE_LOCK_ACQUIRE(curkse, &_thread_signal_lock);
 	sigfunc = _thread_sigact[sig - 1].sa_sigaction;
@@ -389,15 +371,20 @@ _thr_sig_handler(int sig, siginfo_t *info, ucontext_t *ucp)
 				 ucp);
 	} else {
 		if ((__sighandler_t *)sigfunc == SIG_DFL) {
-			if (sigprop(sig) & SA_KILL)
-				kse_thr_interrupt(NULL, KSE_INTR_SIGEXIT, sig);
+			if (sigprop(sig) & SA_KILL) {
+				if (_kse_isthreaded())
+					kse_thr_interrupt(NULL,
+						 KSE_INTR_SIGEXIT, sig);
+				else
+					kill(getpid(), sig);
+			}
 #ifdef NOTYET
 			else if (sigprop(sig) & SA_STOP)
 				kse_thr_interrupt(NULL, KSE_INTR_JOBSTOP, sig);
 #endif
 		}
 	}
-	curthread->error = err_save;
+	errno = err_save;
 	curthread->timeout = timeout_save;
 	curthread->interrupted = intr_save;
 	_kse_critical_enter();
@@ -445,13 +432,13 @@ thr_sig_invoke_handler(struct pthread *curthread, int sig, siginfo_t *info,
 	}
 	KSE_LOCK_RELEASE(curkse, &_thread_signal_lock);
 	KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
-	_kse_critical_leave(&curthread->tcb->tcb_tmbx);
 	/*
 	 * We are processing buffered signals, synchronize working
 	 * signal mask into kernel.
 	 */
 	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
 		__sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL);
+	_kse_critical_leave(&curthread->tcb->tcb_tmbx);
 	ucp->uc_sigmask = sigmask;
 	if (((__sighandler_t *)sigfunc != SIG_DFL) &&
 	    ((__sighandler_t *)sigfunc != SIG_IGN)) {
@@ -462,8 +449,13 @@ thr_sig_invoke_handler(struct pthread *curthread, int sig, siginfo_t *info,
 			    ucp);
 	} else {
 		if ((__sighandler_t *)sigfunc == SIG_DFL) {
-			if (sigprop(sig) & SA_KILL)
-				kse_thr_interrupt(NULL, KSE_INTR_SIGEXIT, sig);
+			if (sigprop(sig) & SA_KILL) {
+				if (_kse_isthreaded())
+					kse_thr_interrupt(NULL,
+						 KSE_INTR_SIGEXIT, sig);
+				else
+					kill(getpid(), sig);
+			}
 #ifdef NOTYET
 			else if (sigprop(sig) & SA_STOP)
 				kse_thr_interrupt(NULL, KSE_INTR_JOBSTOP, sig);
@@ -1049,7 +1041,6 @@ thr_sigframe_restore(struct pthread *thread, struct pthread_sigframe *psf)
 		PANIC("invalid pthread_sigframe\n");
 	thread->flags = psf->psf_flags;
 	thread->interrupted = psf->psf_interrupted;
-	thread->signo = psf->psf_signo;
 	thread->state = psf->psf_state;
 	thread->data = psf->psf_wait_data;
 	thread->wakeup_time = psf->psf_wakeup_time;
@@ -1062,7 +1053,6 @@ thr_sigframe_save(struct pthread *thread, struct pthread_sigframe *psf)
 	psf->psf_flags =
 	    thread->flags & (THR_FLAGS_PRIVATE | THR_FLAGS_IN_TDLIST);
 	psf->psf_interrupted = thread->interrupted;
-	psf->psf_signo = thread->signo;
 	psf->psf_state = thread->state;
 	psf->psf_wait_data = thread->data;
 	psf->psf_wakeup_time = thread->wakeup_time;
@@ -1074,7 +1064,10 @@ _thr_signal_init(void)
 	struct sigaction act;
 	__siginfohandler_t *sigfunc;
 	int i;
+	sigset_t sigset;
 
+	SIGFILLSET(sigset);
+	__sys_sigprocmask(SIG_SETMASK, &sigset, &_thr_initial->sigmask);
 	/* Enter a loop to get the existing signal status: */
 	for (i = 1; i <= _SIG_MAXSIG; i++) {
 		/* Check for signals which cannot be trapped: */
@@ -1111,11 +1104,13 @@ _thr_signal_init(void)
 	act.sa_flags = SA_SIGINFO | SA_RESTART;
 	act.sa_sigaction = (__siginfohandler_t *)&_thr_sig_handler;
 	if (__sys_sigaction(SIGINFO, &act, NULL) != 0) {
+		__sys_sigprocmask(SIG_SETMASK, &_thr_initial->sigmask, NULL);
 		/*
 		 * Abort this process if signal initialisation fails:
 		 */
 		PANIC("Cannot initialize signal handler");
 	}
+	__sys_sigprocmask(SIG_SETMASK, &_thr_initial->sigmask, NULL);
 }
 
 void
diff --git a/lib/libkse/thread/thr_sigaction.c b/lib/libkse/thread/thr_sigaction.c
index c4f5be8f08b5..ed84c2061ed8 100644
--- a/lib/libkse/thread/thr_sigaction.c
+++ b/lib/libkse/thread/thr_sigaction.c
@@ -52,9 +52,6 @@ _sigaction(int sig, const struct sigaction * act, struct sigaction * oact)
 		errno = EINVAL;
 		ret = -1;
 	} else {
-		if (!_kse_isthreaded())
-			return __sys_sigaction(sig, act, oact);
-
 		if (act)
 			newact = *act;
 
diff --git a/lib/libkse/thread/thr_sigmask.c b/lib/libkse/thread/thr_sigmask.c
index 635bac28d8e2..15740f409b38 100644
--- a/lib/libkse/thread/thr_sigmask.c
+++ b/lib/libkse/thread/thr_sigmask.c
@@ -49,9 +49,6 @@ _pthread_sigmask(int how, const sigset_t *set, sigset_t *oset)
 	sigset_t oldset, newset;
 	int ret;
 
-	if (! _kse_isthreaded())
-		_kse_setthreaded(1);
-
 	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
 		ret = __sys_sigprocmask(how, set, oset);
 		if (ret != 0)
diff --git a/lib/libkse/thread/thr_sigpending.c b/lib/libkse/thread/thr_sigpending.c
index ad5354beca33..7a0a76dcb8c3 100644
--- a/lib/libkse/thread/thr_sigpending.c
+++ b/lib/libkse/thread/thr_sigpending.c
@@ -55,8 +55,7 @@ _sigpending(sigset_t *set)
 		ret = EINVAL;
 	}
 	else {
-		if (!_kse_isthreaded() ||
-		    (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM))
+		if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
 			return (__sys_sigpending(set));
 
 		crit = _kse_critical_enter();
diff --git a/lib/libkse/thread/thr_sigprocmask.c b/lib/libkse/thread/thr_sigprocmask.c
index 262848a810ee..d87df58e60c0 100644
--- a/lib/libkse/thread/thr_sigprocmask.c
+++ b/lib/libkse/thread/thr_sigprocmask.c
@@ -46,9 +46,10 @@ _sigprocmask(int how, const sigset_t *set, sigset_t *oset)
 {
 	int ret;
 
-	if (_kse_isthreaded() == 0)
-		ret = __sys_sigprocmask(how, set, oset);
-	else
-		ret = pthread_sigmask(how, set, oset);
+	ret = pthread_sigmask(how, set, oset);
+	if (ret) {
+		errno = ret;
+		ret = -1;
+	}
 	return (ret);
 }
diff --git a/lib/libkse/thread/thr_sigsuspend.c b/lib/libkse/thread/thr_sigsuspend.c
index e3402a468a6e..4d3aa4ec2580 100644
--- a/lib/libkse/thread/thr_sigsuspend.c
+++ b/lib/libkse/thread/thr_sigsuspend.c
@@ -47,8 +47,7 @@ _sigsuspend(const sigset_t *set)
 	sigset_t	oldmask, newmask;
 	int             ret = -1;
 
-	if (!_kse_isthreaded() ||
-	    (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM))
+	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
 		return (__sys_sigsuspend(set));
 
 	/* Check if a new signal set was provided by the caller: */
diff --git a/lib/libkse/thread/thr_sigwait.c b/lib/libkse/thread/thr_sigwait.c
index d3c00381493e..43f932172ffe 100644
--- a/lib/libkse/thread/thr_sigwait.c
+++ b/lib/libkse/thread/thr_sigwait.c
@@ -55,8 +55,7 @@ lib_sigtimedwait(const sigset_t *set, siginfo_t *info,
 	kse_critical_t  crit;
 	siginfo_t	siginfo;
 
-	if (!_kse_isthreaded() ||
-	    (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)) {
+	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
 		if (info == NULL)
 			info = &siginfo;
 		return (__sys_sigtimedwait((sigset_t *)set, info,
diff --git a/lib/libkse/thread/thr_yield.c b/lib/libkse/thread/thr_yield.c
index 1133784945a9..5c24113c2767 100644
--- a/lib/libkse/thread/thr_yield.c
+++ b/lib/libkse/thread/thr_yield.c
@@ -42,7 +42,7 @@ _sched_yield(void)
 {
 	struct pthread	*curthread = _get_curthread();
 
-	if (!_kse_isthreaded() || curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
+	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
 		return (__sys_sched_yield());
 
 	/* Reset the accumulated time slice value for the current thread: */
@@ -60,8 +60,7 @@ _pthread_yield(void)
 {
 	struct pthread	*curthread = _get_curthread();
 
-	if (!_kse_isthreaded() ||
-	    curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
+	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
 		__sys_sched_yield();
 		return;
 	}
diff --git a/lib/libpthread/thread/thr_init.c b/lib/libpthread/thread/thr_init.c
index be3ad8072756..7f6099458d8c 100644
--- a/lib/libpthread/thread/thr_init.c
+++ b/lib/libpthread/thread/thr_init.c
@@ -268,9 +268,7 @@ _libpthread_init(struct pthread *curthread)
 	_kse_initial->k_kseg = _kseg_alloc(NULL);
 	if (_kse_initial->k_kseg == NULL)
 		PANIC("Can't allocate initial kseg.");
-#ifdef SYSTEM_SCOPE_ONLY
 	_kse_initial->k_kseg->kg_flags |= KGF_SINGLE_THREAD;
-#endif
 	_kse_initial->k_schedq = &_kse_initial->k_kseg->kg_schedq;
 
 	TAILQ_INSERT_TAIL(&_kse_initial->k_kseg->kg_kseq, _kse_initial, k_kgqe);
@@ -309,6 +307,9 @@ _libpthread_init(struct pthread *curthread)
 	_kcb_set(_thr_initial->kse->k_kcb);
 	_tcb_set(_thr_initial->kse->k_kcb, _thr_initial->tcb);
 	_thr_initial->kse->k_flags |= KF_INITIALIZED;
+
+	_thr_signal_init();
+	_kse_critical_leave(&_thr_initial->tcb->tcb_tmbx);
 }
 
 /*
@@ -322,9 +323,7 @@ init_main_thread(struct pthread *thread)
 
 	/* Setup the thread attributes. */
 	thread->attr = _pthread_attr_default;
-#ifdef SYSTEM_SCOPE_ONLY
 	thread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
-#endif
 	/*
 	 * Set up the thread stack.
 	 *
diff --git a/lib/libpthread/thread/thr_kern.c b/lib/libpthread/thread/thr_kern.c
index ae151d7b9a84..33b4c54b359a 100644
--- a/lib/libpthread/thread/thr_kern.c
+++ b/lib/libpthread/thread/thr_kern.c
@@ -411,6 +411,9 @@ _kse_setthreaded(int threaded)
 	sigset_t sigset;
 
 	if ((threaded != 0) && (__isthreaded == 0)) {
+		SIGFILLSET(sigset);
+		__sys_sigprocmask(SIG_SETMASK, &sigset, &_thr_initial->sigmask);
+
 		/*
 		 * Tell the kernel to create a KSE for the initial thread
 		 * and enable upcalls in it.
@@ -425,10 +428,11 @@ _kse_setthreaded(int threaded)
 		_tcb_set(_kse_initial->k_kcb, _thr_initial->tcb);
 		KSE_SET_MBOX(_kse_initial, _thr_initial);
 		_kse_initial->k_kcb->kcb_kmbx.km_flags |= KMF_BOUND;
+#else
+		_thr_initial->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
+		_kse_initial->k_kseg->kg_flags &= ~KGF_SINGLE_THREAD;
+		_kse_initial->k_kcb->kcb_kmbx.km_curthread = NULL;
 #endif
-		SIGFILLSET(sigset);
-		__sys_sigprocmask(SIG_SETMASK, &sigset, &_thr_initial->sigmask);
-		_thr_signal_init();
 
 		/*
 		 * Locking functions in libc are required when there are
@@ -963,12 +967,6 @@ kse_sched_multi(struct kse_mailbox *kmbx)
 	 */
 	_tcb_set(curkse->k_kcb, NULL);
 
-	/* This may have returned from a kse_release(). */
-	if (KSE_WAITING(curkse)) {
-		DBG_MSG("Entered upcall when KSE is waiting.");
-		KSE_CLEAR_WAIT(curkse);
-	}
-
 	/* If this is an upcall; take the scheduler lock. */
 	if (curkse->k_switch == 0)
 		KSE_SCHED_LOCK(curkse, curkse->k_kseg);
@@ -1156,16 +1154,16 @@ thr_resume_wrapper(int sig, siginfo_t *siginfo, ucontext_t *ucp)
 {
 	struct pthread *curthread = _get_curthread();
 	struct kse *curkse;
-	int ret, err_save = curthread->error;
+	int ret, err_save = errno;
 
 	DBG_MSG(">>> sig wrapper\n");
 	if (curthread->lock_switch)
 		PANIC("thr_resume_wrapper, lock_switch != 0\n");
 	thr_resume_check(curthread, ucp, NULL);
+	errno = err_save;
 	_kse_critical_enter();
 	curkse = _get_curkse();
 	curthread->tcb->tcb_tmbx.tm_context = *ucp;
-	curthread->error = err_save;
 	ret = _thread_switch(curkse->k_kcb, curthread->tcb, 1);
 	if (ret != 0)
 		PANIC("thr_resume_wrapper: thread has returned "
@@ -2290,11 +2288,7 @@ kse_reinit(struct kse *kse, int sys_scope)
 	kse->k_kseg = 0;
 	kse->k_schedq = 0;
 	kse->k_locklevel = 0;
-	SIGEMPTYSET(kse->k_sigmask);
-	bzero(&kse->k_sigq, sizeof(kse->k_sigq));
-	kse->k_check_sigq = 0;
 	kse->k_flags = 0;
-	kse->k_waiting = 0;
 	kse->k_idle = 0;
 	kse->k_error = 0;
 	kse->k_cpu = 0;
diff --git a/lib/libpthread/thread/thr_nanosleep.c b/lib/libpthread/thread/thr_nanosleep.c
index 8e709ff3b479..57bbef9e37fc 100644
--- a/lib/libpthread/thread/thr_nanosleep.c
+++ b/lib/libpthread/thread/thr_nanosleep.c
@@ -55,8 +55,7 @@ _nanosleep(const struct timespec *time_to_sleep,
 		errno = EINVAL;
 		ret = -1;
 	} else {
-		if (!_kse_isthreaded() ||
-		    (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM))
+		if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
 			return (__sys_nanosleep(time_to_sleep, time_remaining));
 			
 		KSE_GET_TOD(curthread->kse, &ts);
diff --git a/lib/libpthread/thread/thr_private.h b/lib/libpthread/thread/thr_private.h
index 0664aca4b24c..c1ea5928438c 100644
--- a/lib/libpthread/thread/thr_private.h
+++ b/lib/libpthread/thread/thr_private.h
@@ -188,14 +188,10 @@ struct kse {
 	struct lock		k_lock;
 	struct lockuser		k_lockusers[MAX_KSE_LOCKLEVEL];
 	int			k_locklevel;
-	sigset_t		k_sigmask;
-	struct sigstatus	k_sigq[_SIG_MAXSIG];
 	stack_t			k_stack;
-	int			k_check_sigq;
 	int			k_flags;
 #define	KF_STARTED			0x0001	/* kernel kse created */
 #define	KF_INITIALIZED			0x0002	/* initialized on 1st upcall */
-	int			k_waiting;
 	int			k_idle;		/* kse is idle */
 	int			k_error;	/* syscall errno in critical */
 	int			k_cpu;		/* CPU ID when bound */
@@ -294,11 +290,6 @@ do { \
 #define KSE_WAITQ_INSERT(kse, thrd)	kse_waitq_insert(thrd)
 #define	KSE_WAITQ_FIRST(kse)		TAILQ_FIRST(&(kse)->k_schedq->sq_waitq)
 
-#define	KSE_SET_WAIT(kse) 	atomic_store_rel_int(&(kse)->k_waiting, 1)
-
-#define	KSE_CLEAR_WAIT(kse) 	atomic_store_rel_int(&(kse)->k_waiting, 0)
-
-#define	KSE_WAITING(kse)	(kse)->k_waiting != 0
 #define	KSE_WAKEUP(kse)		kse_wakeup(&(kse)->k_kcb->kcb_kmbx)
 
 #define	KSE_SET_IDLE(kse)	((kse)->k_idle = 1)
@@ -733,9 +724,6 @@ struct pthread {
 	 */
 	int			interrupted;
 
-	/* Signal number when in state PS_SIGWAIT: */
-	int			signo;
-
 	/*
 	 * Set to non-zero when this thread has entered a critical
 	 * region.  We allow for recursive entries into critical regions.
diff --git a/lib/libpthread/thread/thr_sig.c b/lib/libpthread/thread/thr_sig.c
index 3c6821284be7..01b0914a4374 100644
--- a/lib/libpthread/thread/thr_sig.c
+++ b/lib/libpthread/thread/thr_sig.c
@@ -310,24 +310,6 @@ _thr_sig_handler(int sig, siginfo_t *info, ucontext_t *ucp)
 
 	DBG_MSG(">>> _thr_sig_handler(%d)\n", sig);
 
-	curkse = _get_curkse();
-	if ((curkse == NULL) || ((curkse->k_flags & KF_STARTED) == 0)) {
-		/* Upcalls are not yet started; just call the handler. */
-		sigfunc = _thread_sigact[sig - 1].sa_sigaction;
-		if (((__sighandler_t *)sigfunc != SIG_DFL) &&
-		    ((__sighandler_t *)sigfunc != SIG_IGN) &&
-		    (sigfunc != (__siginfohandler_t *)_thr_sig_handler)) {
-			if (((_thread_sigact[sig - 1].sa_flags & SA_SIGINFO)
-			    != 0) || (info == NULL))
-				(*(sigfunc))(sig, info, ucp);
-			else
-				(*(sigfunc))(sig,
-				    (siginfo_t*)(intptr_t)info->si_code, ucp);
-		}
-
-		return;
-	}
-
 	curthread = _get_curthread();
 	if (curthread == NULL)
 		PANIC("No current thread.\n");
@@ -359,11 +341,11 @@ _thr_sig_handler(int sig, siginfo_t *info, ucontext_t *ucp)
 	}
 
 	/* It is now safe to invoke signal handler */
-	err_save = curthread->error;
+	err_save = errno;
 	timeout_save = curthread->timeout;
 	intr_save = curthread->interrupted;
-	/* Get a fresh copy of signal mask from kernel, for thread dump only */
-	__sys_sigprocmask(SIG_SETMASK, NULL, &curthread->sigmask);
+	/* Get a fresh copy of signal mask, for thread dump only */
+	curthread->sigmask = ucp->uc_sigmask;
 	_kse_critical_enter();
 	KSE_LOCK_ACQUIRE(curkse, &_thread_signal_lock);
 	sigfunc = _thread_sigact[sig - 1].sa_sigaction;
@@ -389,15 +371,20 @@ _thr_sig_handler(int sig, siginfo_t *info, ucontext_t *ucp)
 				 ucp);
 	} else {
 		if ((__sighandler_t *)sigfunc == SIG_DFL) {
-			if (sigprop(sig) & SA_KILL)
-				kse_thr_interrupt(NULL, KSE_INTR_SIGEXIT, sig);
+			if (sigprop(sig) & SA_KILL) {
+				if (_kse_isthreaded())
+					kse_thr_interrupt(NULL,
+						 KSE_INTR_SIGEXIT, sig);
+				else
+					kill(getpid(), sig);
+			}
 #ifdef NOTYET
 			else if (sigprop(sig) & SA_STOP)
 				kse_thr_interrupt(NULL, KSE_INTR_JOBSTOP, sig);
 #endif
 		}
 	}
-	curthread->error = err_save;
+	errno = err_save;
 	curthread->timeout = timeout_save;
 	curthread->interrupted = intr_save;
 	_kse_critical_enter();
@@ -445,13 +432,13 @@ thr_sig_invoke_handler(struct pthread *curthread, int sig, siginfo_t *info,
 	}
 	KSE_LOCK_RELEASE(curkse, &_thread_signal_lock);
 	KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
-	_kse_critical_leave(&curthread->tcb->tcb_tmbx);
 	/*
 	 * We are processing buffered signals, synchronize working
 	 * signal mask into kernel.
 	 */
 	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
 		__sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL);
+	_kse_critical_leave(&curthread->tcb->tcb_tmbx);
 	ucp->uc_sigmask = sigmask;
 	if (((__sighandler_t *)sigfunc != SIG_DFL) &&
 	    ((__sighandler_t *)sigfunc != SIG_IGN)) {
@@ -462,8 +449,13 @@ thr_sig_invoke_handler(struct pthread *curthread, int sig, siginfo_t *info,
 			    ucp);
 	} else {
 		if ((__sighandler_t *)sigfunc == SIG_DFL) {
-			if (sigprop(sig) & SA_KILL)
-				kse_thr_interrupt(NULL, KSE_INTR_SIGEXIT, sig);
+			if (sigprop(sig) & SA_KILL) {
+				if (_kse_isthreaded())
+					kse_thr_interrupt(NULL,
+						 KSE_INTR_SIGEXIT, sig);
+				else
+					kill(getpid(), sig);
+			}
 #ifdef NOTYET
 			else if (sigprop(sig) & SA_STOP)
 				kse_thr_interrupt(NULL, KSE_INTR_JOBSTOP, sig);
@@ -1049,7 +1041,6 @@ thr_sigframe_restore(struct pthread *thread, struct pthread_sigframe *psf)
 		PANIC("invalid pthread_sigframe\n");
 	thread->flags = psf->psf_flags;
 	thread->interrupted = psf->psf_interrupted;
-	thread->signo = psf->psf_signo;
 	thread->state = psf->psf_state;
 	thread->data = psf->psf_wait_data;
 	thread->wakeup_time = psf->psf_wakeup_time;
@@ -1062,7 +1053,6 @@ thr_sigframe_save(struct pthread *thread, struct pthread_sigframe *psf)
 	psf->psf_flags =
 	    thread->flags & (THR_FLAGS_PRIVATE | THR_FLAGS_IN_TDLIST);
 	psf->psf_interrupted = thread->interrupted;
-	psf->psf_signo = thread->signo;
 	psf->psf_state = thread->state;
 	psf->psf_wait_data = thread->data;
 	psf->psf_wakeup_time = thread->wakeup_time;
@@ -1074,7 +1064,10 @@ _thr_signal_init(void)
 	struct sigaction act;
 	__siginfohandler_t *sigfunc;
 	int i;
+	sigset_t sigset;
 
+	SIGFILLSET(sigset);
+	__sys_sigprocmask(SIG_SETMASK, &sigset, &_thr_initial->sigmask);
 	/* Enter a loop to get the existing signal status: */
 	for (i = 1; i <= _SIG_MAXSIG; i++) {
 		/* Check for signals which cannot be trapped: */
@@ -1111,11 +1104,13 @@ _thr_signal_init(void)
 	act.sa_flags = SA_SIGINFO | SA_RESTART;
 	act.sa_sigaction = (__siginfohandler_t *)&_thr_sig_handler;
 	if (__sys_sigaction(SIGINFO, &act, NULL) != 0) {
+		__sys_sigprocmask(SIG_SETMASK, &_thr_initial->sigmask, NULL);
 		/*
 		 * Abort this process if signal initialisation fails:
 		 */
 		PANIC("Cannot initialize signal handler");
 	}
+	__sys_sigprocmask(SIG_SETMASK, &_thr_initial->sigmask, NULL);
 }
 
 void
diff --git a/lib/libpthread/thread/thr_sigaction.c b/lib/libpthread/thread/thr_sigaction.c
index c4f5be8f08b5..ed84c2061ed8 100644
--- a/lib/libpthread/thread/thr_sigaction.c
+++ b/lib/libpthread/thread/thr_sigaction.c
@@ -52,9 +52,6 @@ _sigaction(int sig, const struct sigaction * act, struct sigaction * oact)
 		errno = EINVAL;
 		ret = -1;
 	} else {
-		if (!_kse_isthreaded())
-			return __sys_sigaction(sig, act, oact);
-
 		if (act)
 			newact = *act;
 
diff --git a/lib/libpthread/thread/thr_sigmask.c b/lib/libpthread/thread/thr_sigmask.c
index 635bac28d8e2..15740f409b38 100644
--- a/lib/libpthread/thread/thr_sigmask.c
+++ b/lib/libpthread/thread/thr_sigmask.c
@@ -49,9 +49,6 @@ _pthread_sigmask(int how, const sigset_t *set, sigset_t *oset)
 	sigset_t oldset, newset;
 	int ret;
 
-	if (! _kse_isthreaded())
-		_kse_setthreaded(1);
-
 	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
 		ret = __sys_sigprocmask(how, set, oset);
 		if (ret != 0)
diff --git a/lib/libpthread/thread/thr_sigpending.c b/lib/libpthread/thread/thr_sigpending.c
index ad5354beca33..7a0a76dcb8c3 100644
--- a/lib/libpthread/thread/thr_sigpending.c
+++ b/lib/libpthread/thread/thr_sigpending.c
@@ -55,8 +55,7 @@ _sigpending(sigset_t *set)
 		ret = EINVAL;
 	}
 	else {
-		if (!_kse_isthreaded() ||
-		    (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM))
+		if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
 			return (__sys_sigpending(set));
 
 		crit = _kse_critical_enter();
diff --git a/lib/libpthread/thread/thr_sigprocmask.c b/lib/libpthread/thread/thr_sigprocmask.c
index 262848a810ee..d87df58e60c0 100644
--- a/lib/libpthread/thread/thr_sigprocmask.c
+++ b/lib/libpthread/thread/thr_sigprocmask.c
@@ -46,9 +46,10 @@ _sigprocmask(int how, const sigset_t *set, sigset_t *oset)
 {
 	int ret;
 
-	if (_kse_isthreaded() == 0)
-		ret = __sys_sigprocmask(how, set, oset);
-	else
-		ret = pthread_sigmask(how, set, oset);
+	ret = pthread_sigmask(how, set, oset);
+	if (ret) {
+		errno = ret;
+		ret = -1;
+	}
 	return (ret);
 }
diff --git a/lib/libpthread/thread/thr_sigsuspend.c b/lib/libpthread/thread/thr_sigsuspend.c
index e3402a468a6e..4d3aa4ec2580 100644
--- a/lib/libpthread/thread/thr_sigsuspend.c
+++ b/lib/libpthread/thread/thr_sigsuspend.c
@@ -47,8 +47,7 @@ _sigsuspend(const sigset_t *set)
 	sigset_t	oldmask, newmask;
 	int             ret = -1;
 
-	if (!_kse_isthreaded() ||
-	    (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM))
+	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
 		return (__sys_sigsuspend(set));
 
 	/* Check if a new signal set was provided by the caller: */
diff --git a/lib/libpthread/thread/thr_sigwait.c b/lib/libpthread/thread/thr_sigwait.c
index d3c00381493e..43f932172ffe 100644
--- a/lib/libpthread/thread/thr_sigwait.c
+++ b/lib/libpthread/thread/thr_sigwait.c
@@ -55,8 +55,7 @@ lib_sigtimedwait(const sigset_t *set, siginfo_t *info,
 	kse_critical_t  crit;
 	siginfo_t	siginfo;
 
-	if (!_kse_isthreaded() ||
-	    (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)) {
+	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
 		if (info == NULL)
 			info = &siginfo;
 		return (__sys_sigtimedwait((sigset_t *)set, info,
diff --git a/lib/libpthread/thread/thr_yield.c b/lib/libpthread/thread/thr_yield.c
index 1133784945a9..5c24113c2767 100644
--- a/lib/libpthread/thread/thr_yield.c
+++ b/lib/libpthread/thread/thr_yield.c
@@ -42,7 +42,7 @@ _sched_yield(void)
 {
 	struct pthread	*curthread = _get_curthread();
 
-	if (!_kse_isthreaded() || curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
+	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
 		return (__sys_sched_yield());
 
 	/* Reset the accumulated time slice value for the current thread: */
@@ -60,8 +60,7 @@ _pthread_yield(void)
 {
 	struct pthread	*curthread = _get_curthread();
 
-	if (!_kse_isthreaded() ||
-	    curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
+	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
 		__sys_sched_yield();
 		return;
 	}