Update the KSE test utility to the new KSE API.

3 files changed, 482 insertions, 319 deletions

diff --git a/tools/KSE/ksetest/Makefile b/tools/KSE/ksetest/Makefile
index f7bb415..5c0a743 100644
--- a/tools/KSE/ksetest/Makefile
+++ b/tools/KSE/ksetest/Makefile
@@ -1,20 +1,7 @@
 # $FreeBSD$
-#	@(#)Makefile	8.1 (Berkeley) 6/2/93
-
 PROG=	ksetest
-SRCS=	kse_threads_test.c kse_asm.S
-#
-# To support "lazy" ps for non root/wheel users
-# add -DLAZY_PS to the cflags.  This helps
-# keep ps from being an unnecessary load
-# on large systems.
-#
-CFLAGS=-static -g -O
-#WARNS=	0
-#DPADD=	${LIBM} ${LIBKVM}
-#LDADD=	-lm -lkvm
-#BINGRP=	kmem
-#BINMODE=2555
-NOMAN=yes
+NOMAN=
+CFLAGS+= -g
+SRCS=	kse_asm.S kse_threads_test.c 
 
 .include <bsd.prog.mk>
diff --git a/tools/KSE/ksetest/kse_asm.S b/tools/KSE/ksetest/kse_asm.S
index a12358c..ae6ac7e 100644
--- a/tools/KSE/ksetest/kse_asm.S
+++ b/tools/KSE/ksetest/kse_asm.S
@@ -1,88 +1,149 @@
-/*-
+/*
+ * Copyright (c) 2002 Jonathan Mini <mini@freebsd.org>.
+ * Copyright (c) 2001 Daniel Eischen <deischen@freebsd.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Neither the name of the author nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
  * $FreeBSD$
  */
 
-#include <machine/asmacros.h>
-
-/*****************************************************************************/
-/* Scheduling                                                                */
-/*****************************************************************************/
-
-	.data
-
-	.text
-
-#define TF_GS		-0x04 /* don't laugh! */
-#define TF_FS		0x00
-#define TF_ES		0x04
-#define TF_DS		0x08
-#define TF_EDI		0x0c
-#define TF_ESI		0x10
-#define TF_EBP		0x14
-#define TF_ISP		0x18
-#define TF_EBX		0x1c
-#define TF_EDX		0x20
-#define TF_ECX		0x24
-#define TF_EAX		0x28
-#define TF_TRAPNO	0x2c
-#define TF_ERR		0x30
-#define TF_EIP		0x34
-#define TF_CS		0x38
-#define TF_EFLAGS	0x3c
-#define TF_ESP		0x40
-#define TF_SS		0x44
+#include <machine/asm.h>
+__FBSDID("$FreeBSD$");
 
 /*
- * savethread
+ * Where do we define these?
  */
-GEN_ENTRY(savethread)
-
-	/* Switch to new thread.  First, save context as needed. */
-	pushl	%edx
-	movl	8(%esp), %edx	/* get context area */
-	
-	movl	%eax,TF_EAX(%edx)
-	movl	%ebx,TF_EBX(%edx)
-	movl	%ecx,TF_ECX(%edx)
-	popl	%eax			/* get dx off the stack again */
-	movl	%eax,TF_EDX(%edx)
-	movl	(%esp),%eax		/* get the return address */
-	movl	%eax,TF_EIP(%edx)
-	movl	%esp,TF_ESP(%edx)
-	movl	%esp,TF_ISP(%edx)	/* XXX */
-	movl	%ebp,TF_EBP(%edx)
-	movl	%esi,TF_ESI(%edx)
-	movl	%edi,TF_EDI(%edx)
-	movl	%cs,TF_CS(%edx)
-	movl	%ds,TF_DS(%edx)
-	movl	%es,TF_ES(%edx)
-	movl	%fs,TF_FS(%edx)
-	movl	%gs,TF_GS(%edx)
-	ret
-
-
-GEN_ENTRY(loadthread)
-	mov	4(%esp), %edx	/* get context area */
+#define	MC_SIZE			640	/* sizeof mcontext_t */
+#define	UC_MC_OFFSET		16	/* offset to mcontext from ucontext */
+#define	UC_MC_LEN_OFFSET	96	/* offset to mc_len from mcontext */
+#define	MC_LEN_OFFSET		80	/* offset to mc_len from mcontext */
+#define	MC_FP_REGS_OFFSET	96	/* offset to FP regs from mcontext */
+#define	MC_FP_CW_OFFSET		96	/* offset to FP control word */
+#define	MC_OWNEDFP_OFFSET	88	/* offset to mc_ownedfp from mcontext */
+#define	KM_STACK_SP_OFFSET	32	/* offset to km_stack.ss_sp */
+#define	KM_STACK_SIZE_OFFSET	36	/* offset to km_stack.ss_sp */
+#define	KM_FUNC_OFFSET		28	/* offset to km_func */
+ 
+/*
+ * int uts_to_thread(thread_mailbox *tdp, thread_mailbox **curthreadp);
+ *
+ * Does not return on success, returns -1 otherwise.
+ */
+ENTRY(uts_to_thread)
+	movl	4(%esp), %edx		/* get address of thread_mailbox */
+					/* .. ucontext_t is at offset 0 */
+	cmpl	$0, %edx		/* check for null pointer */
+	jne	1f
+	movl	$-1, %eax
+	jmp	5f
+1:	cmpl	$MC_SIZE, UC_MC_LEN_OFFSET(%edx) /* is context valid? */
+	je	2f
+	movl	$-1, %eax		/* bzzzt, invalid context */
+	jmp	5f
+2:	movl	8(%esp), %eax		/* get address of curthreadp */
+	movl	%edx, (%eax)		/* we're now the current thread */
+	/*
+	 * From here on, we don't touch the old stack.
+	 */
+	addl	$UC_MC_OFFSET, %edx	/* add offset to mcontext */
+	movl	4(%edx), %gs
+	movl	8(%edx), %fs
+	movl	12(%edx), %es
+	movl	16(%edx), %ds
+	movl	76(%edx), %ss
+	movl	20(%edx), %edi
+	movl	24(%edx), %esi
+	movl	28(%edx), %ebp
+	movl	72(%edx), %esp		/* switch to context defined stack */
+	subl	$4, %esp		/* leave space for the return address */
+	movl	60(%edx), %eax		/* put return address at top of stack */
+	movl	%eax, (%esp)
+	cmpl	$0, MC_OWNEDFP_OFFSET(%edx) /* are FP regs valid? */
+	jz	3f
+	frstor	MC_FP_REGS_OFFSET(%edx) /* restore FP regs */
+	jmp	4f
+3:	fninit
+	fldcw	MC_FP_CW_OFFSET(%edx)
+4:	movl	48(%edx), %eax		/* restore ax, bx, cx */
+	movl	36(%edx), %ebx
+	movl	44(%edx), %ecx
+	pushl	68(%edx)		/* flags on stack */
+	pushl	40(%edx)		/* %edx on stack  */
+	popl	%edx			/* %edx off stack */
+	popf				/* flags off stack */
+5:	ret				/* %eip off stack */
 
-/*	movl	TF_ISP(%edx), %esp */	/* select which is correct */
-	movl	TF_ESP(%edx), %esp	/* get the new stack online */
-	movl	TF_EBP(%edx), %ebp
-	movl	TF_EIP(%edx),%eax
-	push	%eax			/* return adddress */
-#if 0
-	movl	TF_CS(%edx), %cs
-	movl	TF_DS(%edx), %ds
-	movl	TF_ES(%edx), %es
-	movl	TF_FS(%edx), %fs
-	movl	TF_GS(%edx), %gs
-#endif
-	movl	TF_ESI(%edx), %esi
-	movl	TF_EDI(%edx), %edi
+/*
+ * int thread_to_uts(thread_mailbox *tm, kse_mailbox *km);
+ *
+ * Does not return on success, returns -1 otherwise.
+ */
+ENTRY(thread_to_uts)
+	movl	4(%esp), %eax		/* get address of context */
+	cmpl	$0, %eax		/* check for null pointer */
+	jne	1f
+	movl	$-1, %eax
+	jmp	2f
+1:	pushl	%edx			/* save value of edx */
+	movl	%eax, %edx		/* get address of context */
+	addl	$UC_MC_OFFSET, %edx	/* add offset to mcontext */
+	movl	%gs, 4(%edx)
+	movl	%fs, 8(%edx)
+	movl	%es, 12(%edx)
+	movl	%ds, 16(%edx)
+	movl	%edi, 20(%edx)
+	movl	%esi, 24(%edx)
+	movl	%ebp, 28(%edx)
+	movl	%ebx, 36(%edx)
+	movl	$0, 48(%edx)		/* store successful return in eax */
+	popl	%eax			/* get saved value of edx */
+	movl	%eax, 40(%edx)		/* save edx */
+	movl	%ecx, 44(%edx)
+	movl	(%esp), %eax		/* get return address */
+	movl	%eax, 60(%edx)		/* save return address */
+	movl	%ss, 76(%edx)
+	/*
+	 * Don't save floating point registers here.
+	 *
+	 * This is an explicit call to get the current context, so
+	 * the caller is done with the floating point registers.
+	 * Contexts formed by involuntary switches, such as signal delivery,
+	 * have floating point registers saved by the kernel.
+	 */
+	fnstcw	MC_FP_CW_OFFSET(%edx)
+	movl	$0, MC_OWNEDFP_OFFSET(%edx) /* no FP */
+	lahf				/* get eflags */
+	movl	%eax, 68(%edx)		/* store eflags */
+	movl	%esp, %eax		/* setcontext pushes the return  */
+	addl	$4, %eax		/*   address onto the top of the */
+	movl	%eax, 72(%edx)		/*   stack; account for this     */
+	movl	$MC_SIZE, MC_LEN_OFFSET(%edx) /* context is now valid */
+	movl	8(%esp), %edx		/* get address of mailbox */
+	movl	KM_STACK_SP_OFFSET(%edx), %eax	/* get bottom of stack */
+	addl	KM_STACK_SIZE_OFFSET(%edx), %eax /* add length */
+	movl	%eax, %esp		/* switch to the uts's stack */
+	pushl	%edx			/* push the address of the mailbox */
+	pushl	KM_FUNC_OFFSET(%edx)	/* .. the uts can return to itself */
+	pushl	KM_FUNC_OFFSET(%edx)	/* push the address of the uts func */
+2:	ret
 
-	movl	TF_EDX(%edx), %eax
-	pushl	%eax		
-	movl	TF_ECX(%edx), %ecx
-	movl	TF_EBX(%edx), %ebx
-	movl	TF_EAX(%edx), %eax
-	popl	%edx
-	ret
diff --git a/tools/KSE/ksetest/kse_threads_test.c b/tools/KSE/ksetest/kse_threads_test.c
index fb4f22e..09f8786 100644
--- a/tools/KSE/ksetest/kse_threads_test.c
+++ b/tools/KSE/ksetest/kse_threads_test.c
@@ -1,275 +1,390 @@
-/*
+/*-
+ * Copyright (c) 2002 Jonathan Mini (mini@freebsd.org).
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
  * $FreeBSD$
  */
-#define _KERNEL
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <setjmp.h>
+#include <sys/types.h>
+#include <sys/signal.h>
+#include <sys/signalvar.h>
+#include <sys/sysctl.h>
 #include <sys/kse.h>
-#include <sys/queue.h>
-
-/*#define DEBUG*/
-/*************************************************************
- * These should probably be in a .h file
- **************************************************************/
-typedef void thread_fn(void *arg);
-
-struct user_thread {
-	struct thread_mailbox mbox;
-	char		*stack;
-	int		stack_size;
-	TAILQ_ENTRY(user_thread) runq_next;
-};
-
-struct per_kse {
-	struct kse_mailbox mbox;
-	struct user_thread *curthread;
-};
-/*************************************************************
- * Debug stuff
- **************************************************************/
-#ifdef	DEBUG
-
-jmp_buf jb3;
-#define DUMPREGS(desc) do {_setjmp(jb3); printjb(jb3, desc); } while (0)
-
-char *regname[] = {"%eip","%ebx","%esp","%ebp",
-			"%esi","%edi","fpcr","MSK0",
-			"MSK1","MSK2","MSK3"};
-
-
-static 
-printjb(struct _jmp_buf *jb, char *desc)
-{
-	
-	int i;
-	printf("jb (%s) is at 0x%x\n", desc, jb);
-	for( i = 0; i< _JBLEN-4; i++) {
-		printf("jb[%d] (%s) = 0x%x\n", i, regname[i], jb[0]._jb[i]);
-	}
-}
+#include <sys/ucontext.h>
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <time.h>
+#include <unistd.h>
+
+#undef TRACE_UTS
+
+#ifdef TRACE_UTS
+#define	UPFMT(fmt...)	pfmt(#fmt)
+#define	UPSTR(s)	pstr(s)
+#define	UPCHAR(c)	pchar(c)
 #else
-#define DUMPREGS(desc) do {} while (0)
+#define	UPFMT(fmt...)	/* Nothing. */
+#define	UPSTR(s)	/* Nothing. */
+#define	UPCHAR(c)	/* Nothing. */
 #endif
 
-/*************************************************************
- * Globals
- **************************************************************/
-struct per_kse first_kse; /* for NOW cheat and make it global */
-TAILQ_HEAD(, user_thread) runqueue = TAILQ_HEAD_INITIALIZER(runqueue);
-/*************************************************************
- * Implementation parameters
- **************************************************************/
-#define T_STACKSIZE	(16*4096)	/* thread stacksize */
-#define K_STACKSIZE	(1*4096)	/* KSE (UTS) stacksize */
-
-/*************************************************************
- * UTS funcions.
- * Simple round_robin for now.
- **************************************************************/
-static void
-runq_insert(struct user_thread *thread)
-{
-	TAILQ_INSERT_TAIL(&runqueue, thread, runq_next);
-}
+#define MAIN_STACK_SIZE			(1024 * 1024)
+#define THREAD_STACK_SIZE		(32 * 1024)
 
-static struct user_thread *
-select_thread(void)
-{
-	struct user_thread *thread;
+static struct kse_mailbox	uts_mb;
+static struct thread_mailbox	*run_queue;
+static struct thread_mailbox	*aa;
 
-	if ((thread = TAILQ_FIRST(&runqueue))) {
-		TAILQ_REMOVE(&runqueue, thread, runq_next);
-	}
-	return (thread);
-}
+static int progress = 0;
 
-/*************************************************************
- * The UTS upcall entrypoint
- * Called once on startup (and left by longjump)
- * and there-after, returned to by the upcall many times.
- **************************************************************/
-void
-UTS(struct kse_mailbox *ke_mbox)
-{
-	struct user_thread *thread;
-	struct thread_mailbox *completed;
-	struct per_kse *ksedata;
-	int done = 0;	
-
-	/**********************************/
-	/* UTS upcall starts running here. */
-	/**********************************/
-	/**********************************/
-
-	ksedata = ke_mbox->kmbx_UTS_handle;
-	/* If there are returned syscall threads, put them on the run queue */
-	if ((completed = ke_mbox->kmbx_completed_threads)) {
-		ke_mbox->kmbx_completed_threads = NULL;
-		while (completed) {
-			thread = completed->UTS_handle;
-			completed = completed->next_completed;
-			runq_insert(thread);
-		}
-	}
+static void	init_uts(void);
+static void	enter_uts(void);
+static void	pchar(char c);
+static void	pfmt(const char *fmt, ...);
+static void	pstr(const char *s);
+static void	runq_insert(struct thread_mailbox *tm);
+static struct thread_mailbox *runq_remove(void);
+static void	thread_start(const void *func, int arg);
+static void	uts(struct kse_mailbox *km);
 
-	/* find highest priority thread and load it */
-	if ((thread = select_thread())) {
-		ksedata->curthread = thread;
-		ke_mbox->kmbx_current_thread = &thread->mbox;
+extern int uts_to_thread(struct thread_mailbox *tdp, struct thread_mailbox **curthreadp);
 
-		/* loads context similar to longjmp() */
-		loadthread(&thread->mbox.ctx.tfrm.tf_tf);
-		/* NOTREACHED */
-	}
-	kse_yield(); 		/* in the kernel it does a thread_exit() */
-	/* NOTREACHED */
-} 
-
-/*************************************************************
- * Startup mechanism functions
- **************************************************************/
-static int
-kickkse(struct per_kse *ksedata, int newgroup)
+static void
+nano(int len)
 {
-	char * newstack;
-	jmp_buf jb1;
-	jmp_buf jb2;
-	struct kse_mailbox *mboxaddr;
-	struct per_kse *user_UTS_info;
-	int err;
-
-	newstack = malloc(K_STACKSIZE);
-	mboxaddr = &ksedata->mbox;
-	mboxaddr->kmbx_stackbase = newstack;
-	mboxaddr->kmbx_stacksize = K_STACKSIZE;
-	mboxaddr->kmbx_upcall = &UTS;
-	mboxaddr->kmbx_UTS_handle = ksedata;
-	err = kse_new(mboxaddr, newgroup);
-	return(err);
-}
+	struct timespec time_to_sleep;
+	struct timespec time_remaining;
 
+	time_to_sleep.tv_sec = 0;
+	time_to_sleep.tv_nsec = len * 10000;
+	nanosleep(&time_to_sleep, &time_remaining);
+}
 
-static int
-startkse(struct per_kse *ksedata)
+void
+aaaa(int c)
 {
-	return (kickkse(ksedata, 0));
+	for (;;) {
+		pchar(c);
+		nano(1);
+	}
 }
 
-static int
-startksegrp(struct per_kse *ksedata)
+static void
+foof(int sig)
 {
-	return(kickkse(ksedata, 1));
+	pfmt("\n[%d]\n", sig);
+	thread_start(aaaa, '0' + progress++);
 }
 
-void badreturn()
+void
+spin(int arg)
 {
-	printf("thread returned when shouldn't\n");
-	exit(1);
+	for (;;) enter_uts(); sched_yield();
 }
 
-__inline__ void
-pushontostack(struct user_thread *tcb, int value)
+/*
+ * Test Userland Thread Scheduler (UTS) suite for KSE.
+ */
+int
+main(void)
 {
-	int *SP;
+	int i;
 
-	SP = (int *)(tcb->mbox.ctx.tfrm.tf_tf.tf_isp);
-	*--SP = value;
-	tcb->mbox.ctx.tfrm.tf_tf.tf_isp = (int)SP;
+	thread_start(spin, '.');
+	// thread_start(spin);
+	init_uts();
+	for (i = 0;1;i++) {
+//		if (i < 1000)
+//			thread_start(aaaa, 'a' + (i % 26));
+		pchar('A' + (i % 26));
+		nano(5);
+	}
+	pstr("\n** main() exiting **\n");
+	return (EX_OK);
 }
 
-struct user_thread *
-makethread(thread_fn *fn, int arg1, void *arg2)
+
+/*
+ * Enter the UTS from a thread.
+ */
+static void
+enter_uts(void)
 {
-	struct user_thread *tcb;
-
-	/* We could combine these mallocs */
-	tcb = malloc(sizeof *tcb);
-	bzero(tcb, sizeof(*tcb));
-	tcb->mbox.UTS_handle = tcb; /* back pointer */
-
-	/* malloc the thread's stack */
-	/* We COULD mmap it with STACK characteristics */
-	/* Then we could add a guard page. */
-	tcb->stack_size = T_STACKSIZE; /* set the size we want */
-	tcb->stack = malloc(tcb->stack_size);
-
-	/* Make sure there are good defaults */
-	savethread(&tcb->mbox.ctx.tfrm.tf_tf);
-
-	/* set the PC to the fn */
-	tcb->mbox.ctx.tfrm.tf_tf.tf_eip = (int) fn;
-
-	/* Set the stack and push on the args and a dummy return address */
-	tcb->mbox.ctx.tfrm.tf_tf.tf_ebp =
-	tcb->mbox.ctx.tfrm.tf_tf.tf_isp =
-	tcb->mbox.ctx.tfrm.tf_tf.tf_esp =
-	    (int)(&tcb->stack[tcb->stack_size - 16]);
-	pushontostack(tcb, (int)arg2);
-	pushontostack(tcb, (int)arg1);
-	pushontostack(tcb, (int)&badreturn); /* safety return address */
-	return (tcb);
+	struct thread_mailbox	*td;
+
+	/* XXX: We should atomically exchange these two. */
+	td = uts_mb.km_curthread;
+	uts_mb.km_curthread = NULL;
+
+	thread_to_uts(td, &uts_mb);
 }
 
-/*************************************************************
- * code for three separate threads. (so we can see if it works)
- *************************************************************/
-static void 
-thread1_code(void *arg)
+/*
+ * Initialise threading.
+ */
+static void
+init_uts(void)
 {
-	for(;;) {
-		sleep (1);
-		write(1,".",1);
-	}
+	struct thread_mailbox *tm;
+	int mib[2];
+	char	*p;
+	size_t len;
+
+	/*
+	 * Create initial thread.
+	 */
+	tm = (struct thread_mailbox *)calloc(1, sizeof(struct thread_mailbox));
+
+	/* Throw us into its context. */
+	getcontext(&tm->tm_context);
+
+	/* Find our stack. */
+	mib[0] = CTL_KERN;
+	mib[1] = KERN_USRSTACK;
+	len = sizeof(p);
+	if (sysctl(mib, 2, &p, &len, NULL, 0) == -1)
+		pstr("sysctl(CTL_KER.KERN_USRSTACK) failed.\n");
+	pfmt("main() : 0x%x\n", tm);
+	pfmt("eip -> 0x%x\n", tm->tm_context.uc_mcontext.mc_eip);
+	tm->tm_context.uc_stack.ss_sp = p - MAIN_STACK_SIZE;
+	tm->tm_context.uc_stack.ss_size = MAIN_STACK_SIZE;
+
+	/*
+	 * Create KSE mailbox.
+	 */
+	p = (char *)malloc(THREAD_STACK_SIZE);
+	bzero(&uts_mb, sizeof(struct kse_mailbox));
+	uts_mb.km_stack.ss_sp = p;
+	uts_mb.km_stack.ss_size = THREAD_STACK_SIZE;
+	uts_mb.km_func = (void *)uts;
+	pfmt("uts() at : 0x%x\n", uts);
+	pfmt("uts stack at : 0x%x - 0x%x\n", p, p + THREAD_STACK_SIZE);
+
+	/*
+	 * Start KSE scheduling.
+	 */
+	pfmt("kse_new() -> %d\n", kse_new(&uts_mb, 0));
+	uts_mb.km_curthread = tm;
+
+	/*
+	 * Arrange to deliver signals via KSE.
+	 */
+	signal(SIGURG, foof);
 }
 
-static void 
-thread2_code(void *arg)
+/*
+ * Write a single character to stdout, in a thread-safe manner.
+ */
+static void
+pchar(char c)
 {
-	for(;;) {
-		sleep (3);
-		write(1,"+",1);
-	}
+
+	write(STDOUT_FILENO, &c, 1);
 }
 
-static void 
-thread3_code(void *arg)
+/*
+ * Write formatted output to stdout, in a thread-safe manner.
+ *
+ * Recognises the following conversions:
+ *	%c	-> char
+ *	%d	-> signed int (base 10)
+ *	%s	-> string
+ *	%u	-> unsigned int (base 10)
+ *	%x	-> unsigned int (base 16)
+ */
+static void
+pfmt(const char *fmt, ...)
 {
-	for(;;) {
-		sleep (5);
-		write(1,"=",1);
+	static const char digits[16] = "0123456789abcdef";
+	va_list	 ap;
+	char buf[10];
+	char *s;
+	unsigned r, u;
+	int c, d;
+
+	va_start(ap, fmt);
+	while ((c = *fmt++)) {
+		if (c == '%') {
+			c = *fmt++;
+			switch (c) {
+			case 'c':
+				pchar(va_arg(ap, int));
+				continue;
+			case 's':
+				pstr(va_arg(ap, char *));
+				continue;
+			case 'd':
+			case 'u':
+			case 'x':
+				r = ((c == 'u') || (c == 'd')) ? 10 : 16;
+				if (c == 'd') {
+					d = va_arg(ap, unsigned);
+					if (d < 0) {
+						pchar('-');
+						u = (unsigned)(d * -1);
+					} else
+						u = (unsigned)d;
+				} else
+					u = va_arg(ap, unsigned);
+				s = buf;
+				do {
+					*s++ = digits[u % r];
+				} while (u /= r);
+				while (--s >= buf)
+					pchar(*s);
+				continue;
+			}
+		}
+		pchar(c);
 	}
+	va_end(ap);
 }
 
+static void
+pstr(const char *s)
+{
 
+	write(STDOUT_FILENO, s, strlen(s));
+}
 
-int main()
+/*
+ * Insert a thread into the run queue.
+ */
+static void
+runq_insert(struct thread_mailbox *tm)
 {
 
-	/* set up global structures */
-	TAILQ_INIT(&runqueue);
-
-	/* define two threads to run, they are runnable but not yet running */
-	runq_insert( makethread(&thread1_code, 0, NULL));
-	runq_insert( makethread(&thread2_code, 0, NULL));
+	tm->tm_next = run_queue;
+	run_queue = tm;
+}
 
-	/* and one which we will run ourself */
-	first_kse.curthread = makethread(&thread3_code, 0, NULL);
+/*
+ * Select and remove a thread from the run queue.
+ */
+static struct thread_mailbox *
+runq_remove(void)
+{
+	struct thread_mailbox *p, *p1;
+
+	if (run_queue == NULL)
+		return (NULL);
+	p1 = NULL;
+	for (p = run_queue; p->tm_next != NULL; p = p->tm_next)
+		p1 = p;
+	if (p1 == NULL)
+		run_queue = NULL;
+	else
+		p1->tm_next = NULL;
+	return (p);
+}
 
-	/* start two KSEs in different KSEGRPs */
-	if (startkse(&first_kse)) {
-		perror("failed to start KSE");
-		exit(1);
+/*
+ * Userland thread scheduler.
+ */
+static void
+uts(struct kse_mailbox *km)
+{
+	struct thread_mailbox *tm, *p;
+	int ret, i;
+
+	UPSTR("\n--uts() start--\n");
+	UPFMT("mailbox -> %x\n", km);
+
+	/*
+	 * Insert any processes back from being blocked
+	 * in the kernel into the run queue.
+	 */
+	p = km->km_completed;
+	uts_mb.km_completed = NULL;
+	UPFMT("km_completed -> 0x%x", p);
+	while ((tm = p) != NULL) {
+		p = tm->tm_next;
+		UPFMT(" 0x%x", p);
+		runq_insert(tm);
+	}
+	UPCHAR('\n');
+
+	/*
+	 * Process any signals we've recieved (but only if we have
+	 * somewhere to deliver them to).
+	 */
+	if ((run_queue != NULL) && SIGNOTEMPTY(km->km_sigscaught)) {
+		for (i = 0;i < _SIG_MAXSIG;i++)
+			if (SIGISMEMBER(km->km_sigscaught, i)) {
+				signalcontext(&run_queue->tm_context, i, foof);
+				break;
+			}
+		bzero(&km->km_sigscaught, sizeof(sigset_t));
 	}
 
-	/* startksegrp(&second_kse); */ /* we can't do 2 KSEs yet */
-	/* One will be sufficient */
+	/*
+	 * Pull a thread off the run queue.
+	 */
+	p = runq_remove();
+#if 0
+	if ((p == aa) && (progress > 0)) {
+		--progress;
+		signalcontext(&p->tm_context, 1, foof);
+	}
+#endif
 
-	/* we are a thread, start the ball rolling */
-	/* let the kernel know we are it */
-	first_kse.mbox.kmbx_current_thread = &first_kse.curthread->mbox;
-	thread3_code(NULL);
-	return 0;
+	/*
+	 * Either schedule a thread, or idle if none ready to run.
+	 */
+	if (p != NULL) {
+		UPFMT("\n-- uts() scheduling 0x%x--\n", p);
+		UPFMT("eip -> 0x%x progress -> %d\n",
+		    p->tm_context.uc_mcontext.mc_eip, progress);
+		UPSTR("curthread set\n");
+		uts_to_thread(p, &km->km_curthread);
+		UPSTR("\n-- uts_to_thread() failed --\n");
+	}
+	kse_yield();
+	pstr("** uts() exiting **\n");
+	exit(EX_SOFTWARE);
 }
 
+/*
+ * Start a thread.
+ */
+static void
+thread_start(const void *func, int arg)
+{
+	struct thread_mailbox *tm;
+	char *p;
+
+	aa = tm = (struct thread_mailbox *)calloc(1, sizeof(struct thread_mailbox));
+	pfmt("thread_start() : 0x%x %x\n", tm, &aa->tm_context);
+	getcontext(&tm->tm_context);
+	p = (char *)malloc(THREAD_STACK_SIZE);
+	tm->tm_context.uc_stack.ss_sp = p;
+	tm->tm_context.uc_stack.ss_size = THREAD_STACK_SIZE;
+	makecontext(&tm->tm_context, func, 2, arg);
+	// setcontext(&tm->tm_context);
+	runq_insert(tm);
+}