Get context switching between kernel threads going.

Since the stacks for kernel threads are not mapped 1:1 this involves
translating virtual addresses into physical addresses when making
OPAL calls.

16 files changed, 225 insertions, 48 deletions

diff --git a/sys/arch/powerpc64/dev/opal.c b/sys/arch/powerpc64/dev/opal.c
index f6f66874b07..152fc3a3391 100644
--- a/sys/arch/powerpc64/dev/opal.c
+++ b/sys/arch/powerpc64/dev/opal.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: opal.c,v 1.1 2020/06/10 15:01:40 kettenis Exp $	*/
+/*	$OpenBSD: opal.c,v 1.2 2020/06/14 17:56:54 kettenis Exp $	*/
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
  *
@@ -88,7 +88,7 @@ opal_gettime(struct todr_chip_handle *ch, struct timeval *tv)
 	int64_t error;
 
 	do {
-		error = opal_rtc_read(&date, &time);
+		error = opal_rtc_read(opal_phys(&date), opal_phys(&time));
 		if (error == OPAL_BUSY_EVENT)
 			opal_poll_events(NULL);
 	} while (error == OPAL_BUSY_EVENT);
diff --git a/sys/arch/powerpc64/dev/phb.c b/sys/arch/powerpc64/dev/phb.c
index 86726f19f09..4cd808127bd 100644
--- a/sys/arch/powerpc64/dev/phb.c
+++ b/sys/arch/powerpc64/dev/phb.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: phb.c,v 1.6 2020/06/13 22:58:42 kettenis Exp $	*/
+/*	$OpenBSD: phb.c,v 1.7 2020/06/14 17:56:54 kettenis Exp $	*/
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
  *
@@ -383,7 +383,8 @@ phb_conf_read(void *v, pcitag_t tag, int reg)
 	uint16_t pci_error_state;
 	uint8_t freeze_state;
 
-	error = opal_pci_config_read_word(sc->sc_phb_id, tag, reg, &data);
+	error = opal_pci_config_read_word(sc->sc_phb_id,
+	    tag, reg, opal_phys(&data));
 	if (error == OPAL_SUCCESS && data != 0xffffffff)
 		return data;
 
@@ -392,7 +393,7 @@ phb_conf_read(void *v, pcitag_t tag, int reg)
 	 * an error state.  Clear the error.
 	 */
 	error = opal_pci_eeh_freeze_status(sc->sc_phb_id, sc->sc_pe_number,
-	    &freeze_state, &pci_error_state, NULL);
+	    opal_phys(&freeze_state), opal_phys(&pci_error_state), NULL);
 	if (freeze_state)
 		opal_pci_eeh_freeze_clear(sc->sc_phb_id, sc->sc_pe_number,
 		    OPAL_EEH_ACTION_CLEAR_FREEZE_ALL);
@@ -469,11 +470,11 @@ phb_intr_establish(void *v, pci_intr_handle_t ih, int level,
 
 		if (ih.ih_type == PCI_MSI32) {
 			error = opal_get_msi_32(sc->sc_phb_id, 0, xive,
-			    1, &addr32, &data);
+			    1, opal_phys(&addr32), opal_phys(&data));
 			addr = addr32;
 		} else {
 			error = opal_get_msi_64(sc->sc_phb_id, 0, xive,
-			    1, &addr, &data);
+			    1, opal_phys(&addr), opal_phys(&data));
 		}
 		if (error != OPAL_SUCCESS)
 			return NULL;
diff --git a/sys/arch/powerpc64/dev/xive.c b/sys/arch/powerpc64/dev/xive.c
index 77e298fc597..3c96a2e4606 100644
--- a/sys/arch/powerpc64/dev/xive.c
+++ b/sys/arch/powerpc64/dev/xive.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: xive.c,v 1.1 2020/06/13 22:58:42 kettenis Exp $	*/
+/*	$OpenBSD: xive.c,v 1.2 2020/06/14 17:56:54 kettenis Exp $	*/
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
  *
@@ -234,8 +234,9 @@ xive_intr_establish(uint32_t girq, int type, int level,
 		return NULL;
 	lirq = sc->sc_lirq++;
 
-	error = opal_xive_get_irq_info(girq, &flags, &eoi_page,
-	    &trig_page, &esb_shift, NULL);
+	error = opal_xive_get_irq_info(girq, opal_phys(&flags),
+	    opal_phys(&eoi_page), opal_phys(&trig_page),
+	    opal_phys(&esb_shift), NULL);
 	if (error != OPAL_SUCCESS)
 		return NULL;
 	page_size = 1 << esb_shift;
diff --git a/sys/arch/powerpc64/include/cpu.h b/sys/arch/powerpc64/include/cpu.h
index ed1e2b49322..106b4269f3e 100644
--- a/sys/arch/powerpc64/include/cpu.h
+++ b/sys/arch/powerpc64/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.10 2020/06/13 22:58:42 kettenis Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.11 2020/06/14 17:56:54 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -103,6 +103,8 @@ void delay(u_int);
 #define PROC_STACK(p)		0
 #define PROC_PC(p)		0
 
+void	proc_trampoline(void);
+
 static inline void
 intr_enable(void)
 {
diff --git a/sys/arch/powerpc64/include/frame.h b/sys/arch/powerpc64/include/frame.h
index fff56e63634..7cadf7e48c9 100644
--- a/sys/arch/powerpc64/include/frame.h
+++ b/sys/arch/powerpc64/include/frame.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: frame.h,v 1.2 2020/05/22 15:07:47 kettenis Exp $	*/
+/*	$OpenBSD: frame.h,v 1.3 2020/06/14 17:56:54 kettenis Exp $	*/
 
 /*
  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
@@ -38,6 +38,37 @@
  * This is to ensure alignment of the stackpointer
  */
 #define	FRAMELEN	roundup(sizeof(struct trapframe) + 32, 16)
-#define	trapframe(p)	((struct trapframe *)NULL)
+
+struct callframe {
+	register_t	cf_sp;
+	register_t	cf_cr;
+	register_t	cf_lr;
+	register_t	cf_toc;
+};
+
+struct switchframe {
+	register_t	sf_sp;
+	register_t	sf_cr;
+	register_t	sf_lr;		/* unused */
+	register_t	sf_toc;		/* unused */
+	register_t	sf_r14;
+	register_t	sf_r15;
+	register_t	sf_r16;
+	register_t	sf_r17;
+	register_t	sf_r18;
+	register_t	sf_r19;
+	register_t	sf_r20;
+	register_t	sf_r21;
+	register_t	sf_r22;
+	register_t	sf_r23;
+	register_t	sf_r24;
+	register_t	sf_r25;
+	register_t	sf_r26;
+	register_t	sf_r27;
+	register_t	sf_r28;
+	register_t	sf_r29;
+	register_t	sf_r30;
+	register_t	sf_r31;
+};
 
 #endif /* _MACHDEP_FRAME_H_ */
diff --git a/sys/arch/powerpc64/include/opal.h b/sys/arch/powerpc64/include/opal.h
index 0a3f2094d88..741cde370a1 100644
--- a/sys/arch/powerpc64/include/opal.h
+++ b/sys/arch/powerpc64/include/opal.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: opal.h,v 1.9 2020/06/13 22:58:42 kettenis Exp $	*/
+/*	$OpenBSD: opal.h,v 1.10 2020/06/14 17:56:54 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -131,6 +131,9 @@
 #define XIVE_DUMP_EMU_STATE	0x00000005
 
 #ifndef _LOCORE
+
+void	*opal_phys(void *);
+
 int64_t	opal_test(uint64_t);
 int64_t	opal_console_write(int64_t, int64_t *, const uint8_t *);
 int64_t	opal_console_read(int64_t, int64_t *, uint8_t *);
@@ -174,6 +177,7 @@ int64_t	opal_xive_set_vp_info(uint64_t, uint64_t, uint64_t);
 int64_t	opal_xive_dump(uint32_t, uint32_t);
 
 void	opal_printf(const char *fmt, ...);
+
 #endif
 
 #endif /* _MACHINE_OPAL_H_ */
diff --git a/sys/arch/powerpc64/include/pcb.h b/sys/arch/powerpc64/include/pcb.h
index f6bf78bd428..a40e0ee8b50 100644
--- a/sys/arch/powerpc64/include/pcb.h
+++ b/sys/arch/powerpc64/include/pcb.h
@@ -1,7 +1,26 @@
+/*	$OpenBSD: pcb.h,v 1.2 2020/06/14 17:56:54 kettenis Exp $	*/
+
+/*
+ * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
 #ifndef _MACHINE_PCB_H_
 #define _MACHINE_PCB_H_
 
 struct pcb {
+	register_t pcb_sp;
 	u_int	pcb_flags;
 };
 
diff --git a/sys/arch/powerpc64/include/proc.h b/sys/arch/powerpc64/include/proc.h
index 0fe31ea20c9..b5e2281f0b9 100644
--- a/sys/arch/powerpc64/include/proc.h
+++ b/sys/arch/powerpc64/include/proc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: proc.h,v 1.1 2020/05/16 17:11:14 kettenis Exp $	*/
+/*	$OpenBSD: proc.h,v 1.2 2020/06/14 17:56:54 kettenis Exp $	*/
 
 /*
  * Copyright (c) 1991 Regents of the University of California.
@@ -38,6 +38,7 @@
  * Machine-dependent part of the proc structure for arm64.
  */
 struct mdproc {
+	struct trapframe *md_regs;
 	volatile int md_astpending;
 };
 
diff --git a/sys/arch/powerpc64/include/tcb.h b/sys/arch/powerpc64/include/tcb.h
index 26646141826..8b9d671f777 100644
--- a/sys/arch/powerpc64/include/tcb.h
+++ b/sys/arch/powerpc64/include/tcb.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tcb.h,v 1.1 2020/05/16 17:11:14 kettenis Exp $	*/
+/*	$OpenBSD: tcb.h,v 1.2 2020/06/14 17:56:54 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2011 Philip Guenther <guenther@openbsd.org>
@@ -22,9 +22,9 @@
 #ifdef _KERNEL
 
 #define TCB_GET(p)		\
-	((void *)trapframe(p)->fixreg[2])
+	((void *)(p)->p_md.md_regs->fixreg[2])
 #define TCB_SET(p, addr)	\
-	(trapframe(p)->fixreg[2] = (__register_t)(addr))
+	((p)->p_md.md_regs->fixreg[2] = (__register_t)(addr))
 
 #else /* _KERNEL */
 
@@ -34,7 +34,7 @@
 /* powerpc offsets the TCB pointer 0x7000 bytes after the data */
 #define TCB_OFFSET	0x7000
 
-register void *__tcb __asm__ ("r2");
+register void *__tcb __asm__ ("r13");
 #define TCB_GET()		(__tcb)
 #define TCB_SET(tcb)		((__tcb) = (tcb))
 
diff --git a/sys/arch/powerpc64/powerpc64/genassym.cf b/sys/arch/powerpc64/powerpc64/genassym.cf
index cc15a195a0e..92e42abdbd3 100644
--- a/sys/arch/powerpc64/powerpc64/genassym.cf
+++ b/sys/arch/powerpc64/powerpc64/genassym.cf
@@ -1,4 +1,4 @@
-#	$OpenBSD: genassym.cf,v 1.3 2020/05/22 16:27:49 kettenis Exp $
+#	$OpenBSD: genassym.cf,v 1.4 2020/06/14 17:56:54 kettenis Exp $
 #
 # Copyright (c) 1982, 1990 The Regents of the University of California.
 # All rights reserved.
@@ -31,8 +31,13 @@
 #
 
 include <sys/param.h>
+include <sys/proc.h>
+
+include <machine/intr.h>
+include <machine/pcb.h>
 
 struct	cpu_info
+member	ci_curproc
 member	ci_tempsave
 define	CPUSAVE_SRR0	0
 define	CPUSAVE_SRR1	8
@@ -87,3 +92,36 @@ member	srr1
 member	dar
 member	dsisr
 member	exc
+
+struct	pcb
+member	pcb_sp
+
+struct	proc
+member	p_addr
+member	p_stat
+
+export	SONPROC
+
+define	SFRAMELEN	sizeof(struct switchframe)
+struct	switchframe
+member	sf_r14
+member	sf_r15
+member	sf_r16
+member	sf_r17
+member	sf_r18
+member	sf_r19
+member	sf_r20
+member	sf_r21
+member	sf_r22
+member	sf_r23
+member	sf_r24
+member	sf_r25
+member	sf_r26
+member	sf_r27
+member	sf_r28
+member	sf_r29
+member	sf_r30
+member	sf_r31
+member	sf_cr
+
+export	IPL_NONE
diff --git a/sys/arch/powerpc64/powerpc64/locore.S b/sys/arch/powerpc64/powerpc64/locore.S
index d3463a44069..66f1490d2f2 100644
--- a/sys/arch/powerpc64/powerpc64/locore.S
+++ b/sys/arch/powerpc64/powerpc64/locore.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.S,v 1.12 2020/06/13 22:58:42 kettenis Exp $	*/
+/*	$OpenBSD: locore.S,v 1.13 2020/06/14 17:56:54 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -16,6 +16,8 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#include "assym.h"
+
 #include <machine/opal.h>
 #include <machine/psl.h>
 
@@ -55,8 +57,78 @@ cpu_idle_leave:
 
 	.globl cpu_switchto
 cpu_switchto:
+	mflr	%r0
+	std	%r0, 16(%r1)
+	mfcr	%r10
+	stdu	%r1, -SFRAMELEN(%r1)
+	std	%r10, SF_CR(%r1)
+	std	%r14, SF_R14(%r1)
+	std	%r15, SF_R15(%r1)
+	std	%r16, SF_R16(%r1)
+	std	%r17, SF_R17(%r1)
+	std	%r18, SF_R18(%r1)
+	std	%r19, SF_R19(%r1)
+	std	%r20, SF_R20(%r1)
+	std	%r21, SF_R21(%r1)
+	std	%r22, SF_R22(%r1)
+	std	%r23, SF_R23(%r1)
+	std	%r24, SF_R24(%r1)
+	std	%r25, SF_R25(%r1)
+	std	%r26, SF_R26(%r1)
+	std	%r27, SF_R27(%r1)
+	std	%r28, SF_R28(%r1)
+	std	%r29, SF_R29(%r1)
+	std	%r30, SF_R30(%r1)
+	std	%r31, SF_R31(%r1)
+
+	ld	%r31, P_ADDR(%r3)
+	std	%r1, PCB_SP(%r31)
+
+	li	%r31, SONPROC
+	stb	%r31, P_STAT(%r4)
+	std	%r4, CI_CURPROC(%r13)
+
+	ld	%r31, P_ADDR(%r4)
+	ld	%r1, PCB_SP(%r31)
+
+	ld	%r31, SF_R31(%r1)
+	ld	%r30, SF_R30(%r1)
+	ld	%r29, SF_R29(%r1)
+	ld	%r28, SF_R28(%r1)
+	ld	%r27, SF_R27(%r1)
+	ld	%r26, SF_R26(%r1)
+	ld	%r25, SF_R25(%r1)
+	ld	%r24, SF_R24(%r1)
+	ld	%r23, SF_R23(%r1)
+	ld	%r22, SF_R22(%r1)
+	ld	%r21, SF_R21(%r1)
+	ld	%r20, SF_R20(%r1)
+	ld	%r19, SF_R19(%r1)
+	ld	%r18, SF_R18(%r1)
+	ld	%r17, SF_R17(%r1)
+	ld	%r16, SF_R16(%r1)
+	ld	%r15, SF_R15(%r1)
+	ld	%r14, SF_R14(%r1)
+	ld	%r10, SF_CR(%r1)
+	addi	%r1, %r1, SFRAMELEN
+	mtcr	%r10
+	ld	%r0, 16(%r1)
+	mtlr	%r0
 	blr
 
+	.globl proc_trampoline
+proc_trampoline:
+#ifdef MULTIPROCESSOR
+	bl	proc_trampoline_mp
+#endif
+	li	%r3, IPL_NONE
+	bl	splx
+	mr	%r12, %r31
+	mr	%r3, %r30
+	mtctr	%r12
+	bctrl
+	b	trapexit
+
 /*
  * OPAL interfaces
  */
diff --git a/sys/arch/powerpc64/powerpc64/locore0.S b/sys/arch/powerpc64/powerpc64/locore0.S
index baf7a893325..c1c8737c437 100644
--- a/sys/arch/powerpc64/powerpc64/locore0.S
+++ b/sys/arch/powerpc64/powerpc64/locore0.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore0.S,v 1.3 2020/06/06 22:34:08 kettenis Exp $	*/
+/*	$OpenBSD: locore0.S,v 1.4 2020/06/14 17:56:54 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -33,7 +33,7 @@ _start:
 
 	addis	%r1, %r30, (initstack_end - 1b)@ha
 	addi	%r1, %r1, (initstack_end - 1b)@l
-	addi	%r1, %r1, -32
+	addi	%r1, %r1, -(FRAMELEN + 32)
 
 	/*
 	 * Not all kexec(8) flavours actually pass the OPAL entry point.
@@ -68,6 +68,7 @@ _start:
 	.data
 
 	.align PAGE_SHIFT
+	.globl initstack
 initstack:
 	.space USPACE
 initstack_end:
diff --git a/sys/arch/powerpc64/powerpc64/machdep.c b/sys/arch/powerpc64/powerpc64/machdep.c
index fad05d73487..050db4b0f47 100644
--- a/sys/arch/powerpc64/powerpc64/machdep.c
+++ b/sys/arch/powerpc64/powerpc64/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.22 2020/06/14 17:08:17 kettenis Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.23 2020/06/14 17:56:54 kettenis Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -22,6 +22,7 @@
 #include <sys/exec.h>
 #include <sys/exec_elf.h>
 #include <sys/msgbuf.h>
+#include <sys/proc.h>
 #include <sys/reboot.h>
 
 #include <machine/cpufunc.h>
@@ -70,6 +71,8 @@ extern char hvtrapcode[], hvtrapcodeend[];
 extern char generictrap[];
 extern char generichvtrap[];
 
+extern char initstack[];
+
 struct fdt_reg memreg[VM_PHYSSEG_MAX];
 int nmemreg;
 
@@ -89,6 +92,7 @@ void
 init_powernv(void *fdt, void *tocbase)
 {
 	struct fdt_reg reg;
+	register_t uspace;
 	paddr_t trap;
 	uint64_t msr;
 	void *node;
@@ -220,6 +224,10 @@ init_powernv(void *fdt, void *tocbase)
 	isync();
 
 	initmsgbuf((caddr_t)uvm_pageboot_alloc(MSGBUFSIZE), MSGBUFSIZE);
+
+	proc0paddr = (struct user *)initstack;
+	uspace = (register_t)proc0paddr + USPACE - FRAMELEN;
+	proc0.p_md.md_regs = (struct trapframe *)uspace;
 }
 
 void
diff --git a/sys/arch/powerpc64/powerpc64/process_machdep.c b/sys/arch/powerpc64/powerpc64/process_machdep.c
index 112d3b9ee55..8709ed2f3f7 100644
--- a/sys/arch/powerpc64/powerpc64/process_machdep.c
+++ b/sys/arch/powerpc64/powerpc64/process_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: process_machdep.c,v 1.1 2020/05/16 17:11:14 kettenis Exp $	*/
+/*	$OpenBSD: process_machdep.c,v 1.2 2020/06/14 17:56:54 kettenis Exp $	*/
 /*	$NetBSD: process_machdep.c,v 1.1 1996/09/30 16:34:53 ws Exp $	*/
 
 /*
@@ -103,7 +103,7 @@ process_read_fpregs(struct proc *p, struct fpreg *regs)
 int
 process_set_pc(struct proc *p, caddr_t addr)
 {
-	struct trapframe *tf = trapframe(p);
+	struct trapframe *tf = p->p_md.md_regs;
 	
 	tf->srr0 = (u_int32_t)addr;
 	return 0;
diff --git a/sys/arch/powerpc64/powerpc64/trap_subr.S b/sys/arch/powerpc64/powerpc64/trap_subr.S
index 0f1a633da1a..bcfcc82926b 100644
--- a/sys/arch/powerpc64/powerpc64/trap_subr.S
+++ b/sys/arch/powerpc64/powerpc64/trap_subr.S
@@ -1,4 +1,4 @@
-/* $OpenBSD: trap_subr.S,v 1.6 2020/06/13 22:58:42 kettenis Exp $ */
+/* $OpenBSD: trap_subr.S,v 1.7 2020/06/14 17:56:54 kettenis Exp $ */
 /* $NetBSD: trap_subr.S,v 1.20 2002/04/22 23:20:08 kleink Exp $	*/
 
 /*-
@@ -283,5 +283,7 @@ generictrap:
 	addi	%r3, %r1, 48
 	bl	trap
 
+	.globl	trapexit
+trapexit:
 	FRAME_LEAVE(CI_TEMPSAVE)
 	rfid
diff --git a/sys/arch/powerpc64/powerpc64/vm_machdep.c b/sys/arch/powerpc64/powerpc64/vm_machdep.c
index 62ac3db8305..1112931c022 100644
--- a/sys/arch/powerpc64/powerpc64/vm_machdep.c
+++ b/sys/arch/powerpc64/powerpc64/vm_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vm_machdep.c,v 1.1 2020/05/16 17:11:14 kettenis Exp $	*/
+/*	$OpenBSD: vm_machdep.c,v 1.2 2020/06/14 17:56:54 kettenis Exp $	*/
 
 /*-
  * Copyright (c) 1995 Charles M. Hannum.  All rights reserved.
@@ -67,39 +67,36 @@ void
 cpu_fork(struct proc *p1, struct proc *p2, void *stack, void *tcb,
     void (*func)(void *), void *arg)
 {
-#if 0
 	struct pcb *pcb = &p2->p_addr->u_pcb;
 	struct trapframe *tf;
+	struct callframe *cf;
 	struct switchframe *sf;
-
-	// Does any flushing need to be done if process was running?
+	register_t kstack;
 
 	/* Copy the pcb. */
 	*pcb = p1->p_addr->u_pcb;
-	pcb->pcb_fpcpu = NULL;
 
 	pmap_activate(p2);
 
-	tf = (struct trapframe *)((u_long)p2->p_addr
-	    + USPACE
-	    - sizeof(struct trapframe)
-	    - 0x10);
-
-	tf = (struct trapframe *)STACKALIGN(tf);
-	pcb->pcb_tf = tf;
-	*tf = *p1->p_addr->u_pcb.pcb_tf;
+	kstack = (register_t)p2->p_addr + USPACE - FRAMELEN -
+	    (arc4random() & PAGE_MASK & ~_STACKALIGNBYTES);
+	p2->p_md.md_regs = tf = (struct trapframe *)kstack;
+	*tf = *p1->p_md.md_regs;
 
 	if (stack != NULL)
-		tf->tf_sp = STACKALIGN(stack);
+		tf->fixreg[1] = STACKALIGN(stack);
 	if (tcb != NULL)
-		pcb->pcb_tcb = tcb;
+		tf->fixreg[13] = (register_t)tcb;
 
-	sf = (struct switchframe *)tf - 1;
-	sf->sf_x19 = (uint64_t)func;
-	sf->sf_x20 = (uint64_t)arg;
-	sf->sf_lr = (u_int64_t)&proc_trampoline;
-	pcb->pcb_sp = (uint64_t)sf;
-#endif
+	cf = (struct callframe *)tf - 1;
+	memset(cf, 0, sizeof(*cf));
+	cf->cf_lr = (register_t)&proc_trampoline;
+
+	sf = (struct switchframe *)cf - 1;
+	memset(sf, 0, sizeof(*sf));
+	sf->sf_r31 = (register_t)func;
+	sf->sf_r30 = (register_t)arg;
+	pcb->pcb_sp = (register_t)sf;
 }
 
 /*