libthread: simplify

Now that everything uses pthreads and pthreadperthread,
can delete various conditionals, all the custom context code,
and so on. Also update documents.

Fixes #355.

23 files changed, 12 insertions, 1477 deletions

diff --git a/include/libc.h b/include/libc.h
index 4bb537d6..1e24f0bb 100644
--- a/include/libc.h
+++ b/include/libc.h
@@ -473,10 +473,8 @@ extern	_Thread	*(*threadnow)(void);
 typedef struct Lock Lock;
 struct Lock
 {
-#ifdef PLAN9PORT_USING_PTHREADS
 	int init;
 	pthread_mutex_t mutex;
-#endif
 	int held;
 };
 
diff --git a/include/u.h b/include/u.h
index f84e348a..856e10f4 100644
--- a/include/u.h
+++ b/include/u.h
@@ -67,7 +67,6 @@ typedef long p9jmp_buf[sizeof(sigjmp_buf)/sizeof(long)];
 #if defined(__linux__)
 #	include <sys/types.h>
 #	include <pthread.h>
-#	define PLAN9PORT_USING_PTHREADS 1
 #	if defined(__USE_MISC)
 #		undef _NEEDUSHORT
 #		undef _NEEDUINT
@@ -76,7 +75,6 @@ typedef long p9jmp_buf[sizeof(sigjmp_buf)/sizeof(long)];
 #elif defined(__sun__)
 #	include <sys/types.h>
 #	include <pthread.h>
-#	define PLAN9PORT_USING_PTHREADS 1
 #	undef _NEEDUSHORT
 #	undef _NEEDUINT
 #	undef _NEEDULONG
@@ -84,7 +82,6 @@ typedef long p9jmp_buf[sizeof(sigjmp_buf)/sizeof(long)];
 #elif defined(__FreeBSD__)
 #	include <sys/types.h>
 #	include <osreldate.h>
-#	define PLAN9PORT_USING_PTHREADS 1
 #	include <pthread.h>
 #	if !defined(_POSIX_SOURCE)
 #		undef _NEEDUSHORT
@@ -93,7 +90,6 @@ typedef long p9jmp_buf[sizeof(sigjmp_buf)/sizeof(long)];
 #elif defined(__APPLE__)
 #	include <sys/types.h>
 #	include <pthread.h>
-#	define PLAN9PORT_USING_PTHREADS 1
 #	if __GNUC__ < 4
 #		undef _NEEDUSHORT
 #		undef _NEEDUINT
@@ -108,20 +104,19 @@ typedef long p9jmp_buf[sizeof(sigjmp_buf)/sizeof(long)];
 #elif defined(__NetBSD__)
 #	include <sched.h>
 #	include <sys/types.h>
+#	include <pthread.h>
 #	undef _NEEDUSHORT
 #	undef _NEEDUINT
 #	undef _NEEDULONG
 #elif defined(__OpenBSD__)
 #	include <sys/types.h>
 #	include <pthread.h>
-#	define PLAN9PORT_USING_PTHREADS 1
 #	undef _NEEDUSHORT
 #	undef _NEEDUINT
 #	undef _NEEDULONG
 #else
 	/* No idea what system this is -- try some defaults */
 #	include <pthread.h>
-#	define PLAN9PORT_USING_PTHREADS 1
 #endif
 
 #ifndef O_DIRECT
diff --git a/src/libthread/386-ucontext.c b/src/libthread/386-ucontext.c
deleted file mode 100644
index 3afa9513..00000000
--- a/src/libthread/386-ucontext.c
+++ /dev/null
@@ -1,22 +0,0 @@
-#include "threadimpl.h"
-
-void
-makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
-{
-	int *sp;
-
-	sp = USPALIGN(ucp, 4);
-	sp -= argc;
-	memmove(sp, &argc+1, argc*sizeof(int));
-	*--sp = 0;		/* return address */
-	ucp->uc_mcontext.mc_eip = (long)func;
-	ucp->uc_mcontext.mc_esp = (int)sp;
-}
-
-int
-swapcontext(ucontext_t *oucp, ucontext_t *ucp)
-{
-	if(getcontext(oucp) == 0)
-		setcontext(ucp);
-	return 0;
-}
diff --git a/src/libthread/386-ucontext.h b/src/libthread/386-ucontext.h
deleted file mode 100644
index b1ee81b3..00000000
--- a/src/libthread/386-ucontext.h
+++ /dev/null
@@ -1,119 +0,0 @@
-#define	setcontext(u)	setmcontext(&(u)->uc_mcontext)
-#define	getcontext(u)	getmcontext(&(u)->uc_mcontext)
-typedef struct mcontext mcontext_t;
-typedef struct ucontext ucontext_t;
-
-extern	int		swapcontext(ucontext_t*, ucontext_t*);
-extern	void		makecontext(ucontext_t*, void(*)(), int, ...);
-extern	int		getmcontext(mcontext_t*);
-extern	void		setmcontext(mcontext_t*);
-
-/*-
- * Copyright (c) 1999 Marcel Moolenaar
- * 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
- *    in this position and unchanged.
- * 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.
- * 3. The name of the author may not be used to endorse or promote products
- *    derived from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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: src/sys/sys/ucontext.h,v 1.4 1999/10/11 20:33:17 luoqi Exp $
- */
-
-/* #include <machine/ucontext.h> */
-
-/*-
- * Copyright (c) 1999 Marcel Moolenaar
- * 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
- *    in this position and unchanged.
- * 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.
- * 3. The name of the author may not be used to endorse or promote products
- *    derived from this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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: src/sys/i386/include/ucontext.h,v 1.4 1999/10/11 20:33:09 luoqi Exp $
- */
-
-struct mcontext {
-	/*
-	 * The first 20 fields must match the definition of
-	 * sigcontext. So that we can support sigcontext
-	 * and ucontext_t at the same time.
-	 */
-	int	mc_onstack;		/* XXX - sigcontext compat. */
-	int	mc_gs;
-	int	mc_fs;
-	int	mc_es;
-	int	mc_ds;
-	int	mc_edi;
-	int	mc_esi;
-	int	mc_ebp;
-	int	mc_isp;
-	int	mc_ebx;
-	int	mc_edx;
-	int	mc_ecx;
-	int	mc_eax;
-	int	mc_trapno;
-	int	mc_err;
-	int	mc_eip;
-	int	mc_cs;
-	int	mc_eflags;
-	int	mc_esp;			/* machine state */
-	int	mc_ss;
-
-	int	mc_fpregs[28];		/* env87 + fpacc87 + u_long */
-	int	__spare__[17];
-};
-
-struct ucontext {
-	/*
-	 * Keep the order of the first two fields. Also,
-	 * keep them the first two fields in the structure.
-	 * This way we can have a union with struct
-	 * sigcontext and ucontext_t. This allows us to
-	 * support them both at the same time.
-	 * note: the union is not defined, though.
-	 */
-	sigset_t	uc_sigmask;
-	mcontext_t	uc_mcontext;
-
-	struct __ucontext *uc_link;
-	stack_t		uc_stack;
-	int		__spare__[8];
-};
diff --git a/src/libthread/COPYING.SPARC64-CONTEXT b/src/libthread/COPYING.SPARC64-CONTEXT
deleted file mode 100644
index 3b204400..00000000
--- a/src/libthread/COPYING.SPARC64-CONTEXT
+++ /dev/null
@@ -1,458 +0,0 @@
-		  GNU LESSER GENERAL PUBLIC LICENSE
-		       Version 2.1, February 1999
-
- Copyright (C) 1991, 1999 Free Software Foundation, Inc.
-     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
-
-[This is the first released version of the Lesser GPL.  It also counts
- as the successor of the GNU Library Public License, version 2, hence
- the version number 2.1.]
-
-			    Preamble
-
-  The licenses for most software are designed to take away your
-freedom to share and change it.  By contrast, the GNU General Public
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-can use it too, but we suggest you first think carefully about whether
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-conditions are imposed on you (whether by court order, agreement or
-otherwise) that contradict the conditions of this License, they do not
-excuse you from the conditions of this License.  If you cannot
-distribute so as to satisfy simultaneously your obligations under this
-License and any other pertinent obligations, then as a consequence you
-may not distribute the Library at all.  For example, if a patent
-license would not permit royalty-free redistribution of the Library by
-all those who receive copies directly or indirectly through you, then
-the only way you could satisfy both it and this License would be to
-refrain entirely from distribution of the Library.
-
-If any portion of this section is held invalid or unenforceable under any
-particular circumstance, the balance of the section is intended to apply,
-and the section as a whole is intended to apply in other circumstances.
-
-It is not the purpose of this section to induce you to infringe any
-patents or other property right claims or to contest validity of any
-such claims; this section has the sole purpose of protecting the
-integrity of the free software distribution system which is
-implemented by public license practices.  Many people have made
-generous contributions to the wide range of software distributed
-through that system in reliance on consistent application of that
-system; it is up to the author/donor to decide if he or she is willing
-to distribute software through any other system and a licensee cannot
-impose that choice.
-
-This section is intended to make thoroughly clear what is believed to
-be a consequence of the rest of this License.
-
-  12. If the distribution and/or use of the Library is restricted in
-certain countries either by patents or by copyrighted interfaces, the
-original copyright holder who places the Library under this License may add
-an explicit geographical distribution limitation excluding those countries,
-so that distribution is permitted only in or among countries not thus
-excluded.  In such case, this License incorporates the limitation as if
-written in the body of this License.
-
-  13. The Free Software Foundation may publish revised and/or new
-versions of the Lesser General Public License from time to time.
-Such new versions will be similar in spirit to the present version,
-but may differ in detail to address new problems or concerns.
-
-Each version is given a distinguishing version number.  If the Library
-specifies a version number of this License which applies to it and
-"any later version", you have the option of following the terms and
-conditions either of that version or of any later version published by
-the Free Software Foundation.  If the Library does not specify a
-license version number, you may choose any version ever published by
-the Free Software Foundation.
-
-  14. If you wish to incorporate parts of the Library into other free
-programs whose distribution conditions are incompatible with these,
-write to the author to ask for permission.  For software which is
-copyrighted by the Free Software Foundation, write to the Free
-Software Foundation; we sometimes make exceptions for this.  Our
-decision will be guided by the two goals of preserving the free status
-of all derivatives of our free software and of promoting the sharing
-and reuse of software generally.
-
-			    NO WARRANTY
-
-  15. BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO
-WARRANTY FOR THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW.
-EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR
-OTHER PARTIES PROVIDE THE LIBRARY "AS IS" WITHOUT WARRANTY OF ANY
-KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE
-IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE
-LIBRARY IS WITH YOU.  SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME
-THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
-
-  16. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
-WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY
-AND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOU
-FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
-CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
-LIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
-RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
-FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
-SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
-DAMAGES.
-
-		     END OF TERMS AND CONDITIONS
diff --git a/src/libthread/COPYRIGHT b/src/libthread/COPYRIGHT
index d0820965..212b96bc 100644
--- a/src/libthread/COPYRIGHT
+++ b/src/libthread/COPYRIGHT
@@ -42,12 +42,3 @@ Contains parts of an earlier library that has:
  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
  * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
 */
-
-===
-
-The above notices do *NOT* apply to Linux-sparc64-context.S
-or to sparc64-ucontext.c.  Those are functions from
-the GNU C library and are provided for systems that use the GNU C
-library but somehow are missing those functions.  They are
-distributed under the Lesser GPL; see COPYING.SPARC64-CONTEXT.
-
diff --git a/src/libthread/Linux-arm-asm.s b/src/libthread/Linux-arm-asm.s
deleted file mode 100644
index 9bd54f8a..00000000
--- a/src/libthread/Linux-arm-asm.s
+++ /dev/null
@@ -1,41 +0,0 @@
-.globl mygetmcontext
-mygetmcontext:
-	str	r1, [r0,#4]
-	str	r2, [r0,#8]
-	str	r3, [r0,#12]
-	str	r4, [r0,#16]
-	str	r5, [r0,#20]
-	str	r6, [r0,#24]
-	str	r7, [r0,#28]
-	str	r8, [r0,#32]
-	str	r9, [r0,#36]
-	str	r10, [r0,#40]
-	str	r11, [r0,#44]
-	str	r12, [r0,#48]
-	str	r13, [r0,#52]
-	str	r14, [r0,#56]
-	/* store 1 as r0-to-restore */
-	mov	r1, #1
-	str	r1, [r0]
-	/* return 0 */
-	mov	r0, #0
-	mov	pc, lr
-
-.globl mysetmcontext
-mysetmcontext:
-	ldr	r1, [r0,#4]
-	ldr	r2, [r0,#8]
-	ldr	r3, [r0,#12]
-	ldr	r4, [r0,#16]
-	ldr	r5, [r0,#20]
-	ldr	r6, [r0,#24]
-	ldr	r7, [r0,#28]
-	ldr	r8, [r0,#32]
-	ldr	r9, [r0,#36]
-	ldr	r10, [r0,#40]
-	ldr	r11, [r0,#44]
-	ldr	r12, [r0,#48]
-	ldr	r13, [r0,#52]
-	ldr	r14, [r0,#56]
-	ldr	r0, [r0]
-	mov	pc, lr
diff --git a/src/libthread/Linux-sparc64-context.S b/src/libthread/Linux-sparc64-context.S
deleted file mode 100644
index 1cc38391..00000000
--- a/src/libthread/Linux-sparc64-context.S
+++ /dev/null
@@ -1,135 +0,0 @@
-/* Copyright (C) 2001 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-     Contributed by Jakub Jelinek <jakub@redhat.com>.
-
-   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, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
-
-/* Constants shared between setcontext() and getcontext().  Don't
-   install this header file.  */
-
-
-#define UC_LINK		0
-#define __UC_SIGMASK	16
-#define UC_M_PC		40
-#define UC_M_NPC	48
-#define UC_SIGMASK	536
-#define SIGMASK_WORDS	16
-
-/* Copyright (C) 1997, 2001 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Richard Henderson (rth@tamu.edu).
-
-   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, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
-
-#define ENTRY(x) x:
-#define END(x)
-
-/*#include "ucontext_i.h" (up above) */
-
-/* int getcontext(ucontext_t *); */
-
-ENTRY(getcontext)
-
-	ldx	[%o0 + UC_LINK], %o1	/* Preserve uc_link field, the
-					   trap clears it.  */
-	ta	0x6e
-1:
-	ldx	[%o0 + UC_M_PC], %o2
-	ldx	[%o0 + UC_M_NPC], %o3
-	ldx	[%o0 + __UC_SIGMASK], %o4
-	stx	%o1, [%o0 + UC_LINK]
-	add	%o2, 2f - 1b, %o2
-	stx	%o2, [%o0 + UC_M_PC]
-	add	%o3, 2f - 1b, %o3
-	stx	%o3, [%o0 + UC_M_NPC]
-#if SIGMASK_WORDS == 16
-	stx	%o4, [%o0 + UC_SIGMASK]
-	stx	%g0, [%o0 + UC_SIGMASK + 8]
-	stx	%g0, [%o0 + UC_SIGMASK + 16]
-	stx	%g0, [%o0 + UC_SIGMASK + 24]
-	stx	%g0, [%o0 + UC_SIGMASK + 32]
-	stx	%g0, [%o0 + UC_SIGMASK + 40]
-	stx	%g0, [%o0 + UC_SIGMASK + 48]
-	stx	%g0, [%o0 + UC_SIGMASK + 56]
-	stx	%g0, [%o0 + UC_SIGMASK + 64]
-	stx	%g0, [%o0 + UC_SIGMASK + 72]
-	stx	%g0, [%o0 + UC_SIGMASK + 80]
-	stx	%g0, [%o0 + UC_SIGMASK + 88]
-	stx	%g0, [%o0 + UC_SIGMASK + 96]
-	stx	%g0, [%o0 + UC_SIGMASK + 104]
-	stx	%g0, [%o0 + UC_SIGMASK + 112]
-	stx	%g0, [%o0 + UC_SIGMASK + 120]
-#else
-# error Adjust getcontext
-#endif
-2:
-	retl
-	 clr	%o0
-
-END(getcontext)
-
-/* Copyright (C) 1997, 2001 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Richard Henderson (rth@tamu.edu).
-
-   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, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
-
-/*
-#include <sysdep.h>
-#include "ucontext_i.h"
-*/
-
-/* int setcontext(ucontext_t *ctx); */
-.weak setcontext
-ENTRY(setcontext)
-
-	mov	1, %o1
-
-/* int __setcontext(ucontext_t *ctx, int restoremask); */
-ENTRY(__setcontext)
-
-	ldx	[%o0 + UC_SIGMASK], %o2
-	stx	%o2, [%o0 + __UC_SIGMASK]
-	ta	0x6f
-
-END(__setcontext)
-
diff --git a/src/libthread/OpenBSD-386-asm.s b/src/libthread/OpenBSD-386-asm.s
deleted file mode 100644
index ed18d2f0..00000000
--- a/src/libthread/OpenBSD-386-asm.s
+++ /dev/null
@@ -1,45 +0,0 @@
-.globl getmcontext
-getmcontext:
-	movl	4(%esp), %eax
-
-	movl	%fs, 8(%eax)
-	movl	%es, 12(%eax)
-	movl	%ds, 16(%eax)
-	movl	%ss, 76(%eax)
-	movl	%edi, 20(%eax)
-	movl	%esi, 24(%eax)
-	movl	%ebp, 28(%eax)
-	movl	%ebx, 36(%eax)
-	movl	%edx, 40(%eax)
-	movl	%ecx, 44(%eax)
-
-	movl	$1, 48(%eax)	/* %eax */
-	movl	(%esp), %ecx	/* %eip */
-	movl	%ecx, 60(%eax)
-	leal	4(%esp), %ecx	/* %esp */
-	movl	%ecx, 72(%eax)
-
-	movl	44(%eax), %ecx	/* restore %ecx */
-	movl	$0, %eax
-	ret
-
-.globl setmcontext
-setmcontext:
-	movl	4(%esp), %eax
-
-	movl	8(%eax), %fs
-	movl	12(%eax), %es
-	movl	16(%eax), %ds
-	movl	76(%eax), %ss
-	movl	20(%eax), %edi
-	movl	24(%eax), %esi
-	movl	28(%eax), %ebp
-	movl	36(%eax), %ebx
-	movl	40(%eax), %edx
-	movl	44(%eax), %ecx
-
-	movl	72(%eax), %esp
-	pushl	60(%eax)	/* new %eip */
-	movl	48(%eax), %eax
-	ret
-
diff --git a/src/libthread/OpenBSD-power-asm.S b/src/libthread/OpenBSD-power-asm.S
deleted file mode 100644
index 36035eb5..00000000
--- a/src/libthread/OpenBSD-power-asm.S
+++ /dev/null
@@ -1,73 +0,0 @@
-ENTRY(_getmcontext)				/* xxx: instruction scheduling */
-	mflr	%r0
-	mfcr	%r5
-	mfctr	%r6
-	mfxer	%r7
-	stw	%r0, 0*4(%r3)
-	stw	%r5, 1*4(%r3)
-	stw	%r6, 2*4(%r3)
-	stw	%r7, 3*4(%r3)
-
-	stw	%r1, 4*4(%r3)
-	stw	%r2, 5*4(%r3)
-	li	%r5, 1			/* return value for setmcontext */
-	stw	%r5, 6*4(%r3)
-
-	stw	%r13, (0+7)*4(%r3)	/* callee-save GPRs */
-	stw	%r14, (1+7)*4(%r3)	/* xxx: block move */
-	stw	%r15, (2+7)*4(%r3)
-	stw	%r16, (3+7)*4(%r3)
-	stw	%r17, (4+7)*4(%r3)
-	stw	%r18, (5+7)*4(%r3)
-	stw	%r19, (6+7)*4(%r3)
-	stw	%r20, (7+7)*4(%r3)
-	stw	%r21, (8+7)*4(%r3)
-	stw	%r22, (9+7)*4(%r3)
-	stw	%r23, (10+7)*4(%r3)
-	stw	%r24, (11+7)*4(%r3)
-	stw	%r25, (12+7)*4(%r3)
-	stw	%r26, (13+7)*4(%r3)
-	stw	%r27, (14+7)*4(%r3)
-	stw	%r28, (15+7)*4(%r3)
-	stw	%r29, (16+7)*4(%r3)
-	stw	%r30, (17+7)*4(%r3)
-	stw	%r31, (18+7)*4(%r3)
-
-	li	%r3, 0			/* return */
-	blr
-
-ENTRY(_setmcontext)
-	lwz	%r13, (0+7)*4(%r3)	/* callee-save GPRs */
-	lwz	%r14, (1+7)*4(%r3)	/* xxx: block move */
-	lwz	%r15, (2+7)*4(%r3)
-	lwz	%r16, (3+7)*4(%r3)
-	lwz	%r17, (4+7)*4(%r3)
-	lwz	%r18, (5+7)*4(%r3)
-	lwz	%r19, (6+7)*4(%r3)
-	lwz	%r20, (7+7)*4(%r3)
-	lwz	%r21, (8+7)*4(%r3)
-	lwz	%r22, (9+7)*4(%r3)
-	lwz	%r23, (10+7)*4(%r3)
-	lwz	%r24, (11+7)*4(%r3)
-	lwz	%r25, (12+7)*4(%r3)
-	lwz	%r26, (13+7)*4(%r3)
-	lwz	%r27, (14+7)*4(%r3)
-	lwz	%r28, (15+7)*4(%r3)
-	lwz	%r29, (16+7)*4(%r3)
-	lwz	%r30, (17+7)*4(%r3)
-	lwz	%r31, (18+7)*4(%r3)
-
-	lwz	%r1, 4*4(%r3)
-	lwz	%r2, 5*4(%r3)
-
-	lwz	%r0, 0*4(%r3)
-	mtlr	%r0
-	lwz	%r0, 1*4(%r3)
-	mtcr	%r0			/* mtcrf 0xFF, %r0 */
-	lwz	%r0, 2*4(%r3)
-	mtctr	%r0
-	lwz	%r0, 3*4(%r3)
-	mtxer	%r0
-
-	lwz	%r3,	6*4(%r3)
-	blr
diff --git a/src/libthread/OpenBSD-x86_64-asm.S b/src/libthread/OpenBSD-x86_64-asm.S
deleted file mode 100644
index e982cdef..00000000
--- a/src/libthread/OpenBSD-x86_64-asm.S
+++ /dev/null
@@ -1,44 +0,0 @@
-.text
-.align 8
-
-.globl libthread_getmcontext
-libthread_getmcontext:
-	movq	$1, 0*8(%rdi)  // rax
-	movq	%rbx, 1*8(%rdi)
-	movq	%rcx, 2*8(%rdi)
-	movq	%rdx, 3*8(%rdi)
-	movq	%rsi, 4*8(%rdi)
-	movq	%rdi, 5*8(%rdi)
-	movq	%rbp, 6*8(%rdi)
-	movq	%rsp, 7*8(%rdi)
-	movq	%r8, 8*8(%rdi)
-	movq	%r9, 9*8(%rdi)
-	movq	%r10, 10*8(%rdi)
-	movq	%r11, 11*8(%rdi)
-	movq	%r12, 12*8(%rdi)
-	movq	%r13, 13*8(%rdi)
-	movq	%r14, 14*8(%rdi)
-	movq	%r15, 15*8(%rdi)
-	movq	$0, %rax
-	ret
-
-.globl libthread_setmcontext
-libthread_setmcontext:
-	movq	0*8(%rdi), %rax
-	movq	1*8(%rdi), %rbx
-	movq	2*8(%rdi), %rcx
-	movq	3*8(%rdi), %rdx
-	movq	4*8(%rdi), %rsi
-	// %rdi later
-	movq	6*8(%rdi), %rbp
-	movq	7*8(%rdi), %rsp
-	movq	8*8(%rdi), %r8
-	movq	9*8(%rdi), %r9
-	movq	10*8(%rdi), %r10
-	movq	11*8(%rdi), %r11
-	movq	12*8(%rdi), %r12
-	movq	13*8(%rdi), %r13
-	movq	14*8(%rdi), %r14
-	movq	15*8(%rdi), %r15
-	movq	5*8(%rdi), %rdi
-	ret
diff --git a/src/libthread/arm-ucontext.c b/src/libthread/arm-ucontext.c
deleted file mode 100644
index 512ca973..00000000
--- a/src/libthread/arm-ucontext.c
+++ /dev/null
@@ -1,24 +0,0 @@
-#include "threadimpl.h"
-
-void
-makecontext(ucontext_t *uc, void (*fn)(void), int argc, ...)
-{
-	int i, *sp;
-	va_list arg;
-
-	sp = USPALIGN(uc, 4);
-	va_start(arg, argc);
-	for(i=0; i<4 && i<argc; i++)
-		(&uc->uc_mcontext.arm_r0)[i] = va_arg(arg, uint);
-	va_end(arg);
-	uc->uc_mcontext.arm_sp = (uint)sp;
-	uc->uc_mcontext.arm_lr = (uint)fn;
-}
-
-int
-swapcontext(ucontext_t *oucp, const ucontext_t *ucp)
-{
-	if(getcontext(oucp) == 0)
-		setcontext(ucp);
-	return 0;
-}
diff --git a/src/libthread/mkfile b/src/libthread/mkfile
index eca4f4df..40941f43 100644
--- a/src/libthread/mkfile
+++ b/src/libthread/mkfile
@@ -1,15 +1,14 @@
 <$PLAN9/src/mkhdr
 
-SYSOFILES=`{sh ./sysofiles.sh}
 LIB=libthread.a
 OFILES=\
-	$SYSOFILES\
 	bg.$O\
 	channel.$O\
 	daemonize.$O\
 	exec.$O\
 	ioproc.$O\
 	iorw.$O\
+	pthread.$O\
 	ref.$O\
 	thread.$O\
 	wait.$O\
diff --git a/src/libthread/power-ucontext.c b/src/libthread/power-ucontext.c
deleted file mode 100644
index 32a8e931..00000000
--- a/src/libthread/power-ucontext.c
+++ /dev/null
@@ -1,26 +0,0 @@
-#include "threadimpl.h"
-
-void
-makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
-{
-	ulong *sp, *tos;
-	va_list arg;
-
-	if(argc != 2)
-		sysfatal("libthread: makecontext misused");
-	sp = USPALIGN(ucp, 16);
-	ucp->mc.pc = (long)func;
-	ucp->mc.sp = (long)sp;
-	va_start(arg, argc);
-	ucp->mc.r3 = va_arg(arg, long);
-	ucp->mc.r4 = va_arg(arg, long);
-	va_end(arg);
-}
-
-int
-swapcontext(ucontext_t *oucp, ucontext_t *ucp)
-{
-	if(getcontext(oucp) == 0)
-		setcontext(ucp);
-	return 0;
-}
diff --git a/src/libthread/power-ucontext.h b/src/libthread/power-ucontext.h
deleted file mode 100644
index 1985d98d..00000000
--- a/src/libthread/power-ucontext.h
+++ /dev/null
@@ -1,36 +0,0 @@
-#define	setcontext(u)	_setmcontext(&(u)->mc)
-#define	getcontext(u)	_getmcontext(&(u)->mc)
-typedef struct mcontext mcontext_t;
-typedef struct ucontext ucontext_t;
-struct mcontext
-{
-	ulong	pc;		/* lr */
-	ulong	cr;		/* mfcr */
-	ulong	ctr;		/* mfcr */
-	ulong	xer;		/* mfcr */
-	ulong	sp;		/* callee saved: r1 */
-	ulong	toc;		/* callee saved: r2 */
-	ulong	r3;		/* first arg to function, return register: r3 */
-	ulong	gpr[19];	/* callee saved: r13-r31 */
-/*
-// XXX: currently do not save vector registers or floating-point state
-//	ulong	pad;
-//	uvlong	fpr[18];	/ * callee saved: f14-f31 * /
-//	ulong	vr[4*12];	/ * callee saved: v20-v31, 256-bits each * /
-*/
-};
-
-struct ucontext
-{
-	struct {
-		void *ss_sp;
-		uint ss_size;
-	} uc_stack;
-	sigset_t uc_sigmask;
-	mcontext_t mc;
-};
-
-void makecontext(ucontext_t*, void(*)(void), int, ...);
-int swapcontext(ucontext_t*, ucontext_t*);
-int _getmcontext(mcontext_t*);
-void _setmcontext(mcontext_t*);
diff --git a/src/libthread/sparc64-ucontext.c b/src/libthread/sparc64-ucontext.c
deleted file mode 100644
index e4800c19..00000000
--- a/src/libthread/sparc64-ucontext.c
+++ /dev/null
@@ -1,49 +0,0 @@
-/* Copyright (C) 2001 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Jakub Jelinek <jakub@redhat.com>.
-
-   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, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
-
-#include <ucontext.h>
-
-#define UC_M_PC 40
-#define UC_M_NPC 48
-
-extern int __getcontext (ucontext_t *ucp);
-extern int __setcontext (const ucontext_t *ucp, int restoremask);
-
-int
-swapcontext (ucontext_t *oucp, const ucontext_t *ucp)
-{
-  extern void __swapcontext_ret (void);
-  /* Save the current machine context to oucp.  */
-  __getcontext (oucp);
-  /* Modify oucp to skip the __setcontext call on reactivation.  */
-  *(long*)((char*)oucp+UC_M_PC) = (long)__swapcontext_ret;
-  *(long*)((char*)oucp+UC_M_NPC) = (long)__swapcontext_ret + 4;
-  /* Restore the machine context in ucp.  */
-  __setcontext (ucp, 1);
-  return 0;
-}
-
-asm ("							\n\
-	.text						\n\
-	.type	__swapcontext_ret, #function		\n\
-__swapcontext_ret:					\n\
-	return	%i7 + 8					\n\
-	 clr	%o0					\n\
-	.size	__swapcontext_ret, .-__swapcontext_ret	\n\
-     ");
diff --git a/src/libthread/stkmalloc.c b/src/libthread/stkmalloc.c
deleted file mode 100644
index 083aea1b..00000000
--- a/src/libthread/stkmalloc.c
+++ /dev/null
@@ -1,13 +0,0 @@
-#include "threadimpl.h"
-
-void*
-_threadstkalloc(int n)
-{
-	return malloc(n);
-}
-
-void
-_threadstkfree(void *v, int n)
-{
-	free(v);
-}
diff --git a/src/libthread/stkmmap.c b/src/libthread/stkmmap.c
deleted file mode 100644
index f4a24630..00000000
--- a/src/libthread/stkmmap.c
+++ /dev/null
@@ -1,25 +0,0 @@
-#include <u.h>
-#include <sys/mman.h>
-#include "threadimpl.h"
-
-#ifndef MAP_STACK
-#define MAP_STACK 0
-#endif
-
-void*
-_threadstkalloc(int n)
-{
-	void *p;
-
-	p = mmap(nil, n, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON|MAP_STACK, -1, 0);
-	if(p == (void*)-1)
-		return nil;
-	return p;
-}
-
-void
-_threadstkfree(void *v, int n)
-{
-	if(n > 0)
-		munmap(v, n);
-}
diff --git a/src/libthread/sysofiles.sh b/src/libthread/sysofiles.sh
deleted file mode 100644
index cf9e0234..00000000
--- a/src/libthread/sysofiles.sh
+++ /dev/null
@@ -1,27 +0,0 @@
-#!/bin/sh
-
-test -f $PLAN9/config && . $PLAN9/config
-
-echo pthread.o
-
-case "$SYSNAME" in
-OpenBSD)
-	echo stkmmap.o
-	;;
-*)
-	echo stkmalloc.o
-esac
-
-# Various libc don't supply swapcontext, makecontext, so we do.
-case "$SYSNAME-$OBJTYPE" in
-Linux-arm | Linux-sparc64 | NetBSD-arm | OpenBSD-386 | OpenBSD-power | OpenBSD-x86_64)
-	echo $OBJTYPE-ucontext.o
-	;;
-esac
-
-# A few libc don't supply setcontext, getcontext, so we do.
-case "$SYSNAME-$OBJTYPE" in
-Linux-arm | Linux-sparc64 | OpenBSD-386 | OpenBSD-power | OpenBSD-x86_64)
-	echo $SYSNAME-$OBJTYPE-asm.o
-	;;
-esac
diff --git a/src/libthread/thread.c b/src/libthread/thread.c
index 0c764000..d72bf896 100644
--- a/src/libthread/thread.c
+++ b/src/libthread/thread.c
@@ -7,7 +7,6 @@ static	uint		threadnsysproc;
 static	Lock		threadnproclock;
 static	Ref		threadidref;
 static	Proc		*threadmainproc;
-static	int		pthreadperthread = 1;
 
 static	void		addproc(Proc*);
 static	void		delproc(Proc*);
@@ -16,9 +15,7 @@ static	void		delthread(_Threadlist*, _Thread*);
 static	int		onlist(_Threadlist*, _Thread*);
 static	void		addthreadinproc(Proc*, _Thread*);
 static	void		delthreadinproc(Proc*, _Thread*);
-static	void		contextswitch(Context *from, Context *to);
 static	void		procmain(Proc*);
-static	void		procscheduler(Proc*);
 static	int		threadinfo(void*, char*);
 static 	void		pthreadscheduler(Proc *p);
 static	void		pthreadsleepschedlocked(Proc *p, _Thread *t);
@@ -86,114 +83,24 @@ procalloc(void)
 	return p;
 }
 
-static void
-threadstart(uint y, uint x)
-{
-	_Thread *t;
-	ulong z;
-
-//print("threadstart\n");
-	z = (ulong)x << 16;	/* hide undefined 32-bit shift from 32-bit compilers */
-	z <<= 16;
-	z |= y;
-	t = (_Thread*)z;
-
-//print("threadstart sp=%p arg=%p startfn=%p t=%p\n", &t, t, t->startfn, t->startarg);
-	t->startfn(t->startarg);
-/*print("threadexits %p\n", v); */
-	threadexits(nil);
-/*print("not reacehd\n"); */
-}
-
-static _Thread*
-threadalloc(void (*fn)(void*), void *arg, uint stack)
+_Thread*
+_threadcreate(Proc *p, void (*fn)(void*), void *arg, uint stack)
 {
 	_Thread *t;
-	sigset_t zero;
-	uint x, y;
-	ulong z;
 
-	/* allocate the task and stack together */
+	USED(stack);
 	t = malloc(sizeof *t);
 	if(t == nil)
-		sysfatal("threadalloc malloc: %r");
+		sysfatal("threadcreate malloc: %r");
 	memset(t, 0, sizeof *t);
 	t->id = incref(&threadidref);
-//print("fn=%p arg=%p\n", fn, arg);
 	t->startfn = fn;
 	t->startarg = arg;
-//print("makecontext sp=%p t=%p startfn=%p\n", (char*)t->stk+t->stksize, t, t->startfn);
-
-	/* do a reasonable initialization */
-	if(stack == 0)
-		return t;
-	t->stk = _threadstkalloc(stack);
-	if(t->stk == nil)
-		sysfatal("threadalloc malloc stack: %r");
-	t->stksize = stack;
-	memset(&t->context.uc, 0, sizeof t->context.uc);
-	sigemptyset(&zero);
-	sigprocmask(SIG_BLOCK, &zero, &t->context.uc.uc_sigmask);
-//print("makecontext sp=%p t=%p startfn=%p\n", (char*)t->stk+t->stksize, t, t->startfn);
-
-	/* must initialize with current context */
-	if(getcontext(&t->context.uc) < 0)
-		sysfatal("threadalloc getcontext: %r");
-//print("makecontext sp=%p t=%p startfn=%p\n", (char*)t->stk+t->stksize, t, t->startfn);
-
-	/*
-	 * Call makecontext to do the real work.
-	 * To avoid various mistakes on other system software,
-	 * debuggers, and so on, don't get too close to both
-	 * ends of the stack. Just staying away is much easier
-	 * than debugging everything (outside our control)
-	 * that has off-by-one errors.
-	 */
-	t->context.uc.uc_stack.ss_sp = (void*)(t->stk+64);
-	t->context.uc.uc_stack.ss_size = t->stksize-2*64;
-#if defined(__sun__) && !defined(__MAKECONTEXT_V2_SOURCE)		/* sigh */
-	/* can avoid this with __MAKECONTEXT_V2_SOURCE but only on SunOS 5.9 */
-	t->context.uc.uc_stack.ss_sp =
-		(char*)t->context.uc.uc_stack.ss_sp
-		+t->context.uc.uc_stack.ss_size;
-#endif
-	/*
-	 * All this magic is because you have to pass makecontext a
-	 * function that takes some number of word-sized variables,
-	 * and on 64-bit machines pointers are bigger than words.
-	 */
-//print("makecontext sp=%p t=%p startfn=%p\n", (char*)t->stk+t->stksize, t, t->startfn);
-	z = (ulong)t;
-	y = z;
-	z >>= 16;	/* hide undefined 32-bit shift from 32-bit compilers */
-	x = z>>16;
-	makecontext(&t->context.uc, (void(*)(void))threadstart, 2, y, x);
-
-	return t;
-}
-
-_Thread*
-_threadcreate(Proc *p, void (*fn)(void*), void *arg, uint stack)
-{
-	_Thread *t;
-
-	/* defend against bad C libraries */
-	if(stack < (256<<10))
-		stack = 256<<10;
-
-	if(p->nthread == 0 || pthreadperthread)
-		stack = 0; // not using it
-	t = threadalloc(fn, arg, stack);
 	t->proc = p;
-	if(pthreadperthread) {
-		if(p->nthread != 0)
-			_threadpthreadstart(p, t);
-		else
-			t->mainthread = 1;
-	} else {
-		if(p->nthread == 0)
-			p->thread0 = t;
-	}
+	if(p->nthread != 0)
+		_threadpthreadstart(p, t);
+	else
+		t->mainthread = 1;
 	p->nthread++;
 	addthreadinproc(p, t);
 	_threadready(t);
@@ -232,15 +139,8 @@ _threadswitch(void)
 
 	needstack(0);
 	p = proc();
-
 /*print("threadswtch %p\n", p); */
-
-	if(pthreadperthread)
-		pthreadscheduler(p);
-	else if(p->thread == p->thread0)
-		procscheduler(p);
-	else
-		contextswitch(&p->thread->context, &p->schedcontext);
+	pthreadscheduler(p);
 }
 
 void
@@ -339,15 +239,6 @@ threadsysfatal(char *fmt, va_list arg)
 }
 
 static void
-contextswitch(Context *from, Context *to)
-{
-	if(swapcontext(&from->uc, &to->uc) < 0){
-		fprint(2, "swapcontext failed: %r\n");
-		assert(0);
-	}
-}
-
-static void
 procmain(Proc *p)
 {
 	_Thread *t;
@@ -357,7 +248,6 @@ procmain(Proc *p)
 	/* take out first thread to run on system stack */
 	t = p->runqueue.head;
 	delthread(&p->runqueue, t);
-	memset(&t->context.uc, 0, sizeof t->context.uc);
 
 	/* run it */
 	p->thread = t;
@@ -379,84 +269,6 @@ _threadpthreadmain(Proc *p, _Thread *t)
 }
 
 static void
-procscheduler(Proc *p)
-{
-	_Thread *t;
-
-	_threaddebug(nil, "scheduler enter");
-//print("s %p\n", p);
-	for(;;) {
-		/* Finish running current thread. */
-		lock(&p->lock);
-		t = p->thread;
-		p->thread = nil;
-		if(t->exiting){
-			delthreadinproc(p, t);
-			p->nthread--;
-	/*print("nthread %d\n", p->nthread); */
-			_threadstkfree(t->stk, t->stksize);
-			/*
-			 * Cannot free p->thread0 yet: it is used for the
-			 * context switches back to the scheduler.
-			 * Instead, we will free it at the end of this function.
-			 * But all the other threads can be freed now.
-			 */
-			if(t != p->thread0)
-				free(t);
-		}
-
-		/* Pick next thread. */
-		t = procnext(p, nil);
-		if(t == nil)
-			break;
-		_threaddebug(nil, "run %d (%s)", t->id, t->name);
-	//print("run %p %p %p %p\n", t, *(uintptr*)(t->context.uc.mc.sp), t->context.uc.mc.di, t->context.uc.mc.si);
-		unlock(&p->lock);
-
-		/* Switch to next thread. */
-		if(t == p->thread0)
-			return;
-		contextswitch(&p->schedcontext, &t->context);
-
-		_threaddebug(nil, "back in scheduler");
-	/*print("back in scheduler\n"); */
-	}
-
-	/* No more threads in proc. Clean up. */
-	_threaddebug(nil, "scheduler exit");
-	if(p->mainproc){
-		/*
-		 * Stupid bug - on Linux 2.6 and maybe elsewhere,
-		 * if the main thread exits then the others keep running
-		 * but the process shows up as a zombie in ps and is not
-		 * attachable with ptrace.  We'll just sit around pretending
-		 * to be a system proc instead of exiting.
-		 */
-		_threaddaemonize();
-		lock(&threadnproclock);
-		if(++threadnsysproc == threadnproc)
-			threadexitsall(p->msg);
-		p->sysproc = 1;
-		unlock(&threadnproclock);
-		for(;;)
-		 	sleep(1000);
-	}
-
-	delproc(p);
-	lock(&threadnproclock);
-	if(p->sysproc)
-		--threadnsysproc;
-	if(--threadnproc == threadnsysproc)
-		threadexitsall(p->msg);
-	unlock(&threadnproclock);
-	unlock(&p->lock);
-	_threadsetproc(nil);
-	free(p->thread0);
-	free(p);
-	_threadpexit();
-}
-
-static void
 pthreadsleepschedlocked(Proc *p, _Thread *t)
 {
 	_threaddebug(t, "pthreadsleepsched %p %d", p, t->id);;
@@ -913,15 +725,6 @@ main(int argc, char **argv)
 	if(opts == nil)
 		opts = "";
 
-	pthreadperthread = (strstr(opts, "pthreadperthread") != nil);
-#ifdef PLAN9PORT_ASAN
-	// ASAN can't deal with the coroutine stack switches.
-	// In theory it has support for informing it about stack switches,
-	// but even with those calls added it can't deal with things
-	// like fork or exit from a coroutine stack.
-	// Easier to just run in pthread-per-thread mode.
-	pthreadperthread = 1;
-#endif
 	if(threadmaybackground() && strstr(opts, "nodaemon") == nil && getenv("NOLIBTHREADDAEMONIZE") == nil)
 		_threadsetupdaemonize();
 
@@ -956,7 +759,7 @@ main(int argc, char **argv)
 	t = _threadcreate(p, threadmainstart, nil, mainstacksize);
 	t->mainthread = 1;
 	procmain(p);
-	sysfatal("procscheduler returned in threadmain!");
+	sysfatal("procmain returned in libthread");
 	/* does not return */
 	return 0;
 }
diff --git a/src/libthread/threadimpl.h b/src/libthread/threadimpl.h
index 14646031..9eddba21 100644
--- a/src/libthread/threadimpl.h
+++ b/src/libthread/threadimpl.h
@@ -9,36 +9,11 @@
 #	if defined(__APPLE__)
 #		define _XOPEN_SOURCE    /* for Snow Leopard */
 #	endif
-#	include <ucontext.h>
 #endif
 #include <sys/utsname.h>
 #include "libc.h"
 #include "thread.h"
 
-#if defined(__OpenBSD__)
-#	define mcontext libthread_mcontext
-#	define mcontext_t libthread_mcontext_t
-#	define ucontext libthread_ucontext
-#	define ucontext_t libthread_ucontext_t
-#	if defined __i386__
-#		include "386-ucontext.h"
-#	elif defined __amd64__
-#		include "x86_64-ucontext.h"
-#	else
-#		include "power-ucontext.h"
-#	endif
-extern pid_t rfork_thread(int, void*, int(*)(void*), void*);
-#endif
-
-#if defined(__arm__)
-int mygetmcontext(ulong*);
-void mysetmcontext(const ulong*);
-#define	setcontext(u)	mysetmcontext(&(u)->uc_mcontext.arm_r0)
-#define	getcontext(u)	mygetmcontext(&(u)->uc_mcontext.arm_r0)
-#endif
-
-
-typedef struct Context Context;
 typedef struct Execjob Execjob;
 typedef struct Proc Proc;
 typedef struct _Procrendez _Procrendez;
@@ -54,11 +29,6 @@ enum
 	STACK = 8192
 };
 
-struct Context
-{
-	ucontext_t	uc;
-};
-
 struct Execjob
 {
 	int *fd;
@@ -72,11 +42,7 @@ struct _Procrendez
 {
 	Lock		*l;
 	int		asleep;
-#ifdef PLAN9PORT_USING_PTHREADS
 	pthread_cond_t	cond;
-#else
-	int		pid;
-#endif
 };
 
 struct _Thread
@@ -85,15 +51,10 @@ struct _Thread
 	_Thread	*prev;
 	_Thread	*allnext;
 	_Thread	*allprev;
-	Context	context;
 	void	(*startfn)(void*);
 	void	*startarg;
 	uint	id;
-#ifdef PLAN9PORT_USING_PTHREADS
 	pthread_t	osprocid;
-#else
-	int		osprocid;
-#endif
 	uchar	*stk;
 	uint	stksize;
 	int		exiting;
@@ -115,11 +76,7 @@ struct Proc
 	Proc		*next;
 	Proc		*prev;
 	char		msg[128];
-#ifdef PLAN9PORT_USING_PTHREADS
 	pthread_t	osprocid;
-#else
-	int		osprocid;
-#endif
 	Lock		lock;
 	int			nswitch;
 	_Thread		*thread0;
@@ -133,7 +90,6 @@ struct Proc
 	_Procrendez	runrend;
 	Lock		schedlock;
 	_Thread	*schedthread;
-	Context	schedcontext;
 	void		*udata;
 	Jmp		sigjmp;
 	int		mainproc;
diff --git a/src/libthread/x86_64-ucontext.c b/src/libthread/x86_64-ucontext.c
deleted file mode 100644
index 5d1aaefc..00000000
--- a/src/libthread/x86_64-ucontext.c
+++ /dev/null
@@ -1,28 +0,0 @@
-#include "threadimpl.h"
-
-void
-makecontext(ucontext_t *uc, void (*fn)(void), int argc, ...)
-{
-	uintptr *sp;
-	va_list arg;
-
-	if(argc != 2)
-		sysfatal("libthread: makecontext misused");
-	va_start(arg, argc);
-	uc->mc.di = va_arg(arg, uint);
-	uc->mc.si = va_arg(arg, uint);
-	va_end(arg);
-
-	sp = USPALIGN(uc, 16);
-	*--sp = 0;  // fn's return address
-	*--sp = (uintptr)fn;  // return address of setcontext
-	uc->mc.sp = (uintptr)sp;
-}
-
-int
-swapcontext(ucontext_t *oucp, ucontext_t *ucp)
-{
-	if(getcontext(oucp) == 0)
-		setcontext(ucp);
-	return 0;
-}
diff --git a/src/libthread/x86_64-ucontext.h b/src/libthread/x86_64-ucontext.h
deleted file mode 100644
index e0640761..00000000
--- a/src/libthread/x86_64-ucontext.h
+++ /dev/null
@@ -1,42 +0,0 @@
-#define	setcontext(u)	libthread_setmcontext(&(u)->mc)
-#define	getcontext(u)	libthread_getmcontext(&(u)->mc)
-typedef struct mcontext mcontext_t;
-typedef struct ucontext ucontext_t;
-
-struct mcontext
-{
-	uintptr	ax;
-	uintptr	bx;
-	uintptr cx;
-	uintptr dx;
-	uintptr si;
-	uintptr di;
-	uintptr	bp;
-	uintptr sp;
-	uintptr r8;
-	uintptr r9;
-	uintptr r10;
-	uintptr r11;
-	uintptr r12;
-	uintptr r13;
-	uintptr r14;
-	uintptr r15;
-/*
-// XXX: currently do not save vector registers or floating-point state
-*/
-};
-
-struct ucontext
-{
-	struct {
-		void *ss_sp;
-		uint ss_size;
-	} uc_stack;
-	sigset_t uc_sigmask;
-	mcontext_t mc;
-};
-
-void makecontext(ucontext_t*, void(*)(void), int, ...);
-int swapcontext(ucontext_t*, ucontext_t*);
-int libthread_getmcontext(mcontext_t*);
-void libthread_setmcontext(mcontext_t*);