diff --git a/sys/compat/linux/arch/amd64/linux_machdep.c b/sys/compat/linux/arch/amd64/linux_machdep.c
index 5a219ee98807..15cf52e9fb26 100644
--- a/sys/compat/linux/arch/amd64/linux_machdep.c
+++ b/sys/compat/linux/arch/amd64/linux_machdep.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: linux_machdep.c,v 1.6 2005/05/22 19:31:15 fvdl Exp $ */
+/*	$NetBSD: linux_machdep.c,v 1.7 2005/06/22 15:10:51 manu Exp $ */
 
 /*-
  * Copyright (c) 2005 Emmanuel Dreyfus, all rights reserved.
@@ -33,7 +33,7 @@
 
 #include <sys/cdefs.h>
 
-__KERNEL_RCSID(0, "$NetBSD: linux_machdep.c,v 1.6 2005/05/22 19:31:15 fvdl Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_machdep.c,v 1.7 2005/06/22 15:10:51 manu Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -188,7 +188,8 @@ linux_sendsig(ksi, mask)
 
 	bzero(&sigframe, sizeof(sigframe));
 	if (ps->sa_sigdesc[sig].sd_vers != 0)
-		sigframe.pretcode = (char *)ps->sa_sigdesc[sig].sd_tramp;
+		sigframe.pretcode = 
+		    (char *)(u_long)ps->sa_sigdesc[sig].sd_tramp;
 	else
 		sigframe.pretcode = NULL;
 
diff --git a/sys/compat/linux/arch/amd64/linux_syscall.h b/sys/compat/linux/arch/amd64/linux_syscall.h
index 809e0c71cf82..3450cf163d02 100644
--- a/sys/compat/linux/arch/amd64/linux_syscall.h
+++ b/sys/compat/linux/arch/amd64/linux_syscall.h
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_syscall.h,v 1.4 2005/05/22 19:29:40 fvdl Exp $ */
+/* $NetBSD: linux_syscall.h,v 1.5 2005/06/22 15:10:51 manu Exp $ */
 
 /*
  * System call numbers.
@@ -163,7 +163,7 @@
 /* syscall: "getsockopt" ret: "int" args: "int" "int" "int" "void *" "int *" */
 #define	LINUX_SYS_getsockopt	55
 
-/* syscall: "clone" ret: "int" args: "int" "void *" */
+/* syscall: "clone" ret: "int" args: "int" "void *" "void *" "void *" */
 #define	LINUX_SYS_clone	56
 
 /* syscall: "fork" ret: "int" args: */
@@ -496,6 +496,9 @@
 /* syscall: "getdents64" ret: "int" args: "int" "struct linux_dirent64 *" "unsigned int" */
 #define	LINUX_SYS_getdents64	217
 
+/* syscall: "set_tid_address" ret: "int" args: "int *" */
+#define	LINUX_SYS_set_tid_address	218
+
 /* syscall: "clock_settime" ret: "int" args: "clockid_t" "struct linux_timespec *" */
 #define	LINUX_SYS_clock_settime	227
 
diff --git a/sys/compat/linux/arch/amd64/linux_syscallargs.h b/sys/compat/linux/arch/amd64/linux_syscallargs.h
index 31979f4290a8..c5142e2f18a2 100644
--- a/sys/compat/linux/arch/amd64/linux_syscallargs.h
+++ b/sys/compat/linux/arch/amd64/linux_syscallargs.h
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_syscallargs.h,v 1.4 2005/05/22 19:29:40 fvdl Exp $ */
+/* $NetBSD: linux_syscallargs.h,v 1.5 2005/06/22 15:10:51 manu Exp $ */
 
 /*
  * System call argument lists.
@@ -218,6 +218,8 @@ struct linux_sys_getsockopt_args {
 struct linux_sys_clone_args {
 	syscallarg(int) flags;
 	syscallarg(void *) stack;
+	syscallarg(void *) parent_tidptr;
+	syscallarg(void *) child_tidptr;
 };
 
 struct linux_sys_execve_args {
@@ -608,6 +610,10 @@ struct linux_sys_getdents64_args {
 	syscallarg(unsigned int) count;
 };
 
+struct linux_sys_set_tid_address_args {
+	syscallarg(int *) tid;
+};
+
 struct linux_sys_clock_settime_args {
 	syscallarg(clockid_t) which;
 	syscallarg(struct linux_timespec *) tp;
@@ -964,6 +970,8 @@ int	linux_sys_time(struct lwp *, void *, register_t *);
 
 int	linux_sys_getdents64(struct lwp *, void *, register_t *);
 
+int	linux_sys_set_tid_address(struct lwp *, void *, register_t *);
+
 int	linux_sys_clock_settime(struct lwp *, void *, register_t *);
 
 int	linux_sys_clock_gettime(struct lwp *, void *, register_t *);
diff --git a/sys/compat/linux/arch/amd64/linux_syscalls.c b/sys/compat/linux/arch/amd64/linux_syscalls.c
index 12631aa9d35e..b71bca52d3ff 100644
--- a/sys/compat/linux/arch/amd64/linux_syscalls.c
+++ b/sys/compat/linux/arch/amd64/linux_syscalls.c
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_syscalls.c,v 1.4 2005/05/22 19:29:40 fvdl Exp $ */
+/* $NetBSD: linux_syscalls.c,v 1.5 2005/06/22 15:10:51 manu Exp $ */
 
 /*
  * System call names.
@@ -8,7 +8,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_syscalls.c,v 1.4 2005/05/22 19:29:40 fvdl Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_syscalls.c,v 1.5 2005/06/22 15:10:51 manu Exp $");
 
 #if defined(_KERNEL_OPT)
 #if defined(_KERNEL_OPT)
@@ -248,7 +248,7 @@ const char *const linux_syscallnames[] = {
 	"#215 (unimplemented epoll_wait_old)",		/* 215 = unimplemented epoll_wait_old */
 	"#216 (unimplemented remap_file_pages)",		/* 216 = unimplemented remap_file_pages */
 	"getdents64",			/* 217 = getdents64 */
-	"#218 (unimplemented set_tid_address)",		/* 218 = unimplemented set_tid_address */
+	"set_tid_address",			/* 218 = set_tid_address */
 	"#219 (unimplemented restart_syscall)",		/* 219 = unimplemented restart_syscall */
 	"#220 (unimplemented semtimedop)",		/* 220 = unimplemented semtimedop */
 	"#221 (unimplemented fadvise64)",		/* 221 = unimplemented fadvise64 */
diff --git a/sys/compat/linux/arch/amd64/linux_sysent.c b/sys/compat/linux/arch/amd64/linux_sysent.c
index d6fbeb202f72..b5e2e0af2799 100644
--- a/sys/compat/linux/arch/amd64/linux_sysent.c
+++ b/sys/compat/linux/arch/amd64/linux_sysent.c
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_sysent.c,v 1.4 2005/05/22 19:29:40 fvdl Exp $ */
+/* $NetBSD: linux_sysent.c,v 1.5 2005/06/22 15:10:51 manu Exp $ */
 
 /*
  * System call switch table.
@@ -8,7 +8,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_sysent.c,v 1.4 2005/05/22 19:29:40 fvdl Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_sysent.c,v 1.5 2005/06/22 15:10:51 manu Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_compat_43.h"
@@ -142,7 +142,7 @@ struct sysent linux_sysent[] = {
 	    linux_sys_setsockopt },		/* 54 = setsockopt */
 	{ 5, s(struct linux_sys_getsockopt_args), 0,
 	    linux_sys_getsockopt },		/* 55 = getsockopt */
-	{ 2, s(struct linux_sys_clone_args), 0,
+	{ 4, s(struct linux_sys_clone_args), 0,
 	    linux_sys_clone },			/* 56 = clone */
 	{ 0, 0, 0,
 	    sys_fork },				/* 57 = fork */
@@ -466,8 +466,8 @@ struct sysent linux_sysent[] = {
 	    linux_sys_nosys },			/* 216 = unimplemented remap_file_pages */
 	{ 3, s(struct linux_sys_getdents64_args), 0,
 	    linux_sys_getdents64 },		/* 217 = getdents64 */
-	{ 0, 0, 0,
-	    linux_sys_nosys },			/* 218 = unimplemented set_tid_address */
+	{ 1, s(struct linux_sys_set_tid_address_args), 0,
+	    linux_sys_set_tid_address },	/* 218 = set_tid_address */
 	{ 0, 0, 0,
 	    linux_sys_nosys },			/* 219 = unimplemented restart_syscall */
 	{ 0, 0, 0,
diff --git a/sys/compat/linux/arch/amd64/syscalls.master b/sys/compat/linux/arch/amd64/syscalls.master
index 4e0960e6462e..3eb452e1d43c 100644
--- a/sys/compat/linux/arch/amd64/syscalls.master
+++ b/sys/compat/linux/arch/amd64/syscalls.master
@@ -1,4 +1,4 @@
-	$NetBSD: syscalls.master,v 1.4 2005/05/22 19:29:15 fvdl Exp $
+	$NetBSD: syscalls.master,v 1.5 2005/06/22 15:10:51 manu Exp $
 
 ;	@(#)syscalls.master	8.1 (Berkeley) 7/19/93
 
@@ -153,7 +153,8 @@
 			    int optname, void *optval, int optlen); }
 55	STD		{ int linux_sys_getsockopt(int s, int level, \
 			    int optname, void *optval, int *optlen); }
-56	STD		{ int linux_sys_clone(int flags, void *stack); }
+56	STD		{ int linux_sys_clone(int flags, void *stack, \
+			    void *parent_tidptr, void *child_tidptr); }
 57	NOARGS		{ int sys_fork(void); }
 58	NOARGS		{ int sys___vfork14(void); }
 59	STD		{ int linux_sys_execve(const char *path, char **argp, \
@@ -365,7 +366,7 @@
 216	UNIMPL		remap_file_pages
 217	STD		{ int linux_sys_getdents64(int fd, \
 			    struct linux_dirent64 *dent, unsigned int count); }
-218	UNIMPL		set_tid_address
+218	STD		{ int linux_sys_set_tid_address(int *tid); }
 219	UNIMPL		restart_syscall
 220	UNIMPL		semtimedop
 221	UNIMPL		fadvise64
diff --git a/sys/compat/linux/common/linux_emuldata.h b/sys/compat/linux/common/linux_emuldata.h
index d80108686eb6..c6180022f95f 100644
--- a/sys/compat/linux/common/linux_emuldata.h
+++ b/sys/compat/linux/common/linux_emuldata.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: linux_emuldata.h,v 1.7 2005/02/26 23:10:19 perry Exp $	*/
+/*	$NetBSD: linux_emuldata.h,v 1.8 2005/06/22 15:10:51 manu Exp $	*/
 
 /*-
  * Copyright (c) 1998,2002 The NetBSD Foundation, Inc.
@@ -48,6 +48,7 @@
 struct linux_emuldata_shared {
 	caddr_t	p_break;	/* Processes' idea of break */
 	int refs;
+	pid_t group_pid;	/* PID of Linux process (group of threads) */
 };
 
 struct linux_emuldata {
@@ -57,6 +58,10 @@ struct linux_emuldata {
 	int	debugreg[8];	/* GDB information for ptrace - for use, */
 				/* see ../arch/i386/linux_ptrace.c */
 	struct linux_emuldata_shared *s;
+	int *child_set_tid;	/* in clone(): Child's TID to set on clone */
+	int *child_clear_tid;	/* in clone(): Child's TID to clear on exit */
+	int *set_tid;		/* in clone(): Own TID to set on clone */
+	int *clear_tid;		/* Own TID to clear on exit */
 };
 
 #endif /* !_COMMON_LINUX_EMULDATA_H */
diff --git a/sys/compat/linux/common/linux_exec.c b/sys/compat/linux/common/linux_exec.c
index 8f5b8a108948..67892d02dc1b 100644
--- a/sys/compat/linux/common/linux_exec.c
+++ b/sys/compat/linux/common/linux_exec.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: linux_exec.c,v 1.76 2005/06/02 16:54:52 tsutsui Exp $	*/
+/*	$NetBSD: linux_exec.c,v 1.77 2005/06/22 15:10:51 manu Exp $	*/
 
 /*-
  * Copyright (c) 1994, 1995, 1998, 2000 The NetBSD Foundation, Inc.
@@ -38,7 +38,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_exec.c,v 1.76 2005/06/02 16:54:52 tsutsui Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_exec.c,v 1.77 2005/06/22 15:10:51 manu Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -81,6 +81,8 @@ static void linux_e_proc_fork __P((struct proc *, struct proc *, int));
 static void linux_e_proc_exit __P((struct proc *));
 static void linux_e_proc_init __P((struct proc *, struct proc *, int));
 
+static void linux_userret_settid __P((struct lwp *, void *));
+
 /*
  * Execve(2). Just check the alternate emulation path, and pass it on
  * to the NetBSD execve().
@@ -159,6 +161,7 @@ linux_e_proc_init(p, parent, forkflags)
 {
 	struct linux_emuldata *e = p->p_emuldata;
 	struct linux_emuldata_shared *s;
+	struct linux_emuldata *ep = NULL;
 
 	if (!e) {
 		/* allocate new Linux emuldata */
@@ -172,9 +175,17 @@ linux_e_proc_init(p, parent, forkflags)
 
 	memset(e, '\0', sizeof(struct linux_emuldata));
 
+	if (parent)
+		ep = parent->p_emuldata;
+
 	if (forkflags & FORK_SHAREVM) {
-		struct linux_emuldata *e2 = parent->p_emuldata;
-		s = e2->s;
+#ifdef DIAGNOSTIC
+		if (ep == NULL) {
+			killproc(p, "FORK_SHAREVM while emuldata is NULL\n");
+			return;
+		}
+#endif
+		s = ep->s;
 		s->refs++;
 	} else {
 		struct vmspace *vm;
@@ -193,9 +204,33 @@ linux_e_proc_init(p, parent, forkflags)
 		vm = (parent) ? parent->p_vmspace : p->p_vmspace;
 		s->p_break = vm->vm_daddr + ctob(vm->vm_dsize);
 
+		/*
+		 * Linux threads are emulated as NetBSD processes (not lwp)
+		 * We use native PID for Linux TID. The Linux TID is the
+		 * PID of the first process in the group. It is stored
+		 * here
+		 */
+		s->group_pid = p->p_pid;
 	}
 
 	e->s = s;
+
+	/* 
+	 * initialize TID pointers. ep->child_clear_tid and 
+	 * ep->child_set_tid will not be used beyond this point.
+	 */
+	e->child_clear_tid = NULL;
+	e->child_set_tid = NULL;
+	if (ep != NULL) {
+		e->clear_tid = ep->child_clear_tid;
+		e->set_tid = ep->child_set_tid;
+		ep->child_clear_tid = NULL;
+		ep->child_set_tid = NULL;
+	} else {
+		e->clear_tid = NULL;
+		e->set_tid = NULL;
+	}
+
 	p->p_emuldata = e;
 }
 
@@ -222,6 +257,23 @@ linux_e_proc_exit(p)
 {
 	struct linux_emuldata *e = p->p_emuldata;
 
+	/* Emulate LINUX_CLONE_CHILD_CLEARTID */
+	if (e->clear_tid != NULL) {
+		int error;
+		int null = 0;
+
+		if ((error = copyout(&null, 
+		    e->clear_tid, 
+		    sizeof(null))) != 0)
+			printf("linux_e_proc_exit: cannot clear TID\n");
+
+#ifdef notyet /* Not yet implemented */
+		if ((error = linux_sys_futex(e->clear_tid, 
+		    LINUX_FUTEX_WAKE, 1, NULL, NULL, 0)) != 0)
+			printf("linux_e_proc_exit: linux_sys_futex failed\n");
+#endif
+	}
+
 	/* free Linux emuldata and set the pointer to null */
 	e->s->refs--;
 	if (e->s->refs == 0)
@@ -238,6 +290,8 @@ linux_e_proc_fork(p, parent, forkflags)
 	struct proc *p, *parent;
 	int forkflags;
 {
+	struct linux_emuldata *e;
+
 	/*
 	 * The new process might share some vmspace-related stuff
 	 * with parent, depending on fork flags (CLONE_VM et.al).
@@ -246,4 +300,36 @@ linux_e_proc_fork(p, parent, forkflags)
 	 */
 	p->p_emuldata = NULL;
 	linux_e_proc_init(p, parent, forkflags);
+
+	/* 
+	 * Emulate LINUX_CLONE_CHILD_SETTID: This cannot be done  
+	 * right now because the child VM is not set up. We will
+	 * do it at userret time.
+	 */
+	e = p->p_emuldata;
+	if (e->set_tid != NULL) 
+		p->p_userret = (*linux_userret_settid);
+
+	return;
+}
+
+static void
+linux_userret_settid(l, arg)
+	struct lwp *l;
+	void *arg;
+{
+	struct proc *p = l->l_proc;
+	struct linux_emuldata *led = p->p_emuldata;
+	int error;
+
+	p->p_userret = NULL;
+
+	/* Emulate LINUX_CLONE_CHILD_SETTID  */
+	if (led->set_tid != NULL) {
+		if ((error = copyout(&p->p_pid,
+		    led->set_tid, sizeof(p->p_pid))) != 0)
+			printf("linux_userret_settid: cannot set TID\n");
+	}
+
+	return;	
 }
diff --git a/sys/compat/linux/common/linux_sched.c b/sys/compat/linux/common/linux_sched.c
index 74eaef7caa59..f7d5c6701044 100644
--- a/sys/compat/linux/common/linux_sched.c
+++ b/sys/compat/linux/common/linux_sched.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: linux_sched.c,v 1.18 2004/09/10 22:22:20 wiz Exp $	*/
+/*	$NetBSD: linux_sched.c,v 1.19 2005/06/22 15:10:51 manu Exp $	*/
 
 /*-
  * Copyright (c) 1999 The NetBSD Foundation, Inc.
@@ -42,7 +42,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_sched.c,v 1.18 2004/09/10 22:22:20 wiz Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_sched.c,v 1.19 2005/06/22 15:10:51 manu Exp $");
 
 #include <sys/param.h>
 #include <sys/mount.h>
@@ -56,6 +56,7 @@ __KERNEL_RCSID(0, "$NetBSD: linux_sched.c,v 1.18 2004/09/10 22:22:20 wiz Exp $")
 
 #include <compat/linux/common/linux_types.h>
 #include <compat/linux/common/linux_signal.h>
+#include <compat/linux/common/linux_emuldata.h>
 
 #include <compat/linux/linux_syscallargs.h>
 
@@ -70,8 +71,16 @@ linux_sys_clone(l, v, retval)
 	struct linux_sys_clone_args /* {
 		syscallarg(int) flags;
 		syscallarg(void *) stack;
+#ifdef __amd64__
+		syscallarg(void *) parent_tidptr;
+		syscallarg(void *) child_tidptr;
+#endif
 	} */ *uap = v;
 	int flags, sig;
+	int error;
+#ifdef __amd64__
+	struct linux_emuldata *led;
+#endif
 
 	/*
 	 * We don't support the Linux CLONE_PID or CLONE_PTRACE flags.
@@ -108,14 +117,44 @@ linux_sys_clone(l, v, retval)
 		return (EINVAL);
 	sig = linux_to_native_signo[sig];
 
+#ifdef __amd64__
+	led = (struct linux_emuldata *)l->l_proc->p_emuldata;
+
+	if (SCARG(uap, flags) & LINUX_CLONE_PARENT_SETTID) {
+		if (SCARG(uap, parent_tidptr) == NULL) {
+			printf("linux_sys_clone: NULL parent_tidptr\n");
+			return EINVAL;
+		}
+
+		if ((error = copyout(&l->l_proc->p_pid,
+		    SCARG(uap, parent_tidptr), 
+		    sizeof(l->l_proc->p_pid))) != 0)
+			return error;
+	}
+
+	/* CLONE_CHILD_CLEARTID: TID clear in the child on exit() */
+	if (SCARG(uap, flags) & LINUX_CLONE_CHILD_CLEARTID)
+		led->child_clear_tid = SCARG(uap, child_tidptr);
+	else	
+		led->child_clear_tid = NULL;
+
+	/* CLONE_CHILD_SETTID: TID set in the child on clone() */
+	if (SCARG(uap, flags) & LINUX_CLONE_CHILD_SETTID)
+		led->child_set_tid = SCARG(uap, child_tidptr);
+	else
+		led->child_set_tid = NULL;
+#endif
 	/*
 	 * Note that Linux does not provide a portable way of specifying
 	 * the stack area; the caller must know if the stack grows up
 	 * or down.  So, we pass a stack size of 0, so that the code
 	 * that makes this adjustment is a noop.
 	 */
-	return (fork1(l, flags, sig, SCARG(uap, stack), 0,
-	    NULL, NULL, retval, NULL));
+	if ((error = fork1(l, flags, sig, SCARG(uap, stack), 0,
+	    NULL, NULL, retval, NULL)) != 0)
+		return error;
+
+	return 0;
 }
 
 int
@@ -367,3 +406,24 @@ linux_sys_exit_group(l, v, retval)
 	return 0;
 }
 #endif /* !__m68k__ */
+
+#ifdef __amd64__
+int
+linux_sys_set_tid_address(l, v, retval)
+	struct lwp *l;
+	void *v;
+	register_t *retval;
+{
+	struct linux_sys_set_tid_address_args /* {
+		syscallarg(int *) tidptr;
+	} */ *uap = v;
+	struct linux_emuldata *led;
+
+	led = (struct linux_emuldata *)l->l_proc->p_emuldata;
+	led->clear_tid = SCARG(uap, tid);
+
+	*retval = l->l_proc->p_pid;
+
+	return 0;
+}
+#endif /* __amd64__ */