Add missing copyrights. Thanks to Jason Thorpe for politely noting the

mistake...

2 files changed, 1032 insertions, 0 deletions

diff --git a/sys/powerpc/aim/vm_machdep.c b/sys/powerpc/aim/vm_machdep.c
new file mode 100644
index 0000000..89edb49
--- /dev/null
+++ b/sys/powerpc/aim/vm_machdep.c
@@ -0,0 +1,516 @@
+/*-
+ * Copyright (c) 1982, 1986 The Regents of the University of California.
+ * Copyright (c) 1989, 1990 William Jolitz
+ * Copyright (c) 1994 John Dyson
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department, and William Jolitz.
+ *
+ * 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University 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 THE REGENTS 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 REGENTS 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.
+ *
+ *	from: @(#)vm_machdep.c	7.3 (Berkeley) 5/13/91
+ *	Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
+ *	$Id: vm_machdep.c,v 1.1 1998/06/10 10:53:40 dfr Exp $
+ */
+/*
+ * Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Author: Chris G. Demetriou
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/malloc.h>
+#include <sys/buf.h>
+#include <sys/vnode.h>
+#include <sys/vmmeter.h>
+#include <sys/kernel.h>
+#include <sys/sysctl.h>
+
+#include <machine/clock.h>
+#include <machine/cpu.h>
+#include <machine/md_var.h>
+#include <machine/prom.h>
+
+#include <vm/vm.h>
+#include <vm/vm_param.h>
+#include <vm/vm_prot.h>
+#include <sys/lock.h>
+#include <vm/vm_kern.h>
+#include <vm/vm_page.h>
+#include <vm/vm_map.h>
+#include <vm/vm_extern.h>
+
+#include <sys/user.h>
+
+/*
+ * quick version of vm_fault
+ */
+void
+vm_fault_quick(v, prot)
+	caddr_t v;
+	int prot;
+{
+	if (prot & VM_PROT_WRITE)
+		subyte(v, fubyte(v));
+	else
+		fubyte(v);
+}
+
+/*
+ * Finish a fork operation, with process p2 nearly set up.
+ * Copy and update the pcb, set up the stack so that the child
+ * ready to run and return to user mode.
+ */
+void
+cpu_fork(p1, p2)
+	register struct proc *p1, *p2;
+{
+	struct user *up = p2->p_addr;
+	int i;
+
+	p2->p_md.md_tf = p1->p_md.md_tf;
+	p2->p_md.md_flags = p1->p_md.md_flags & MDP_FPUSED;
+
+	/*
+	 * Cache the physical address of the pcb, so we can
+	 * swap to it easily.
+	 */
+	p2->p_md.md_pcbpaddr = (void*) vtophys((vm_offset_t) &up->u_pcb);
+
+	/*
+	 * Simulate a write to the process's U-area pages,
+	 * so that the system doesn't lose badly.
+	 * (If this isn't done, the kernel can't read or
+	 * write the kernel stack.  "Ouch!")
+	 */
+	for (i = 0; i < UPAGES; i++)
+		pmap_emulate_reference(p2, (vm_offset_t)up + i * PAGE_SIZE,
+		    0, 1);
+
+	/*
+	 * Copy floating point state from the FP chip to the PCB
+	 * if this process has state stored there.
+	 */
+	if (p1 == fpcurproc) {
+		alpha_pal_wrfen(1);
+		savefpstate(&fpcurproc->p_addr->u_pcb.pcb_fp);
+		alpha_pal_wrfen(0);
+	}
+
+	/*
+	 * Copy pcb and stack from proc p1 to p2.
+	 * We do this as cheaply as possible, copying only the active
+	 * part of the stack.  The stack and pcb need to agree;
+	 */
+	p2->p_addr->u_pcb = p1->p_addr->u_pcb;
+	p2->p_addr->u_pcb.pcb_hw.apcb_usp = alpha_pal_rdusp();
+
+	/*
+	 * Arrange for a non-local goto when the new process
+	 * is started, to resume here, returning nonzero from setjmp.
+	 */
+#ifdef DIAGNOSTIC
+	if (p1 != curproc)
+		panic("cpu_fork: curproc");
+	if ((up->u_pcb.pcb_hw.apcb_flags & ALPHA_PCB_FLAGS_FEN) != 0)
+		printf("DANGER WILL ROBINSON: FEN SET IN cpu_fork!\n");
+#endif
+
+	/*
+	 * create the child's kernel stack, from scratch.
+	 */
+	{
+		struct trapframe *p2tf;
+
+		/*
+		 * Pick a stack pointer, leaving room for a trapframe;
+		 * copy trapframe from parent so return to user mode
+		 * will be to right address, with correct registers.
+		 */
+		p2tf = p2->p_md.md_tf = (struct trapframe *)
+		    ((char *)p2->p_addr + USPACE - sizeof(struct trapframe));
+		bcopy(p1->p_md.md_tf, p2->p_md.md_tf,
+		    sizeof(struct trapframe));
+
+		/*
+		 * Set up return-value registers as fork() libc stub expects.
+		 */
+		p2tf->tf_regs[FRAME_V0] = p1->p_pid;	/* parent's pid */
+		p2tf->tf_regs[FRAME_A3] = 0;		/* no error */
+		p2tf->tf_regs[FRAME_A4] = 1;		/* is child */
+
+		/*
+		 * Arrange for continuation at child_return(), which
+		 * will return to exception_return().  Note that the child
+		 * process doesn't stay in the kernel for long!
+		 * 
+		 * This is an inlined version of cpu_set_kpc.
+		 */
+		up->u_pcb.pcb_hw.apcb_ksp = (u_int64_t)p2tf;	
+		up->u_pcb.pcb_context[0] =
+		    (u_int64_t)child_return;		/* s0: pc */
+		up->u_pcb.pcb_context[1] =
+		    (u_int64_t)exception_return;	/* s1: ra */
+		up->u_pcb.pcb_context[2] = (u_long) p2;	/* s2: a0 */
+		up->u_pcb.pcb_context[7] =
+		    (u_int64_t)switch_trampoline;	/* ra: assembly magic */
+	}
+}
+
+/*
+ * Intercept the return address from a freshly forked process that has NOT
+ * been scheduled yet.
+ *
+ * This is needed to make kernel threads stay in kernel mode.
+ */
+void
+cpu_set_fork_handler(p, func, arg)
+	struct proc *p;
+	void (*func) __P((void *));
+	void *arg;
+{
+	/*
+	 * Note that the trap frame follows the args, so the function
+	 * is really called like this:  func(arg, frame);
+	 */
+	p->p_addr->u_pcb.pcb_context[0] = (u_long) func;
+	p->p_addr->u_pcb.pcb_context[2] = (u_long) arg;
+}
+
+/*
+ * cpu_exit is called as the last action during exit.
+ * We release the address space of the process, block interrupts,
+ * and call switch_exit.  switch_exit switches to proc0's PCB and stack,
+ * then jumps into the middle of cpu_switch, as if it were switching
+ * from proc0.
+ */
+void
+cpu_exit(p)
+	register struct proc *p;
+{
+	if (p == fpcurproc)
+		fpcurproc = NULL;
+
+	(void) splhigh();
+	cnt.v_swtch++;
+	cpu_switch(p);
+	panic("cpu_exit");
+}
+
+void
+cpu_wait(p)
+	struct proc *p;
+{
+	/* drop per-process resources */
+	pmap_dispose_proc(p);
+
+	/* and clean-out the vmspace */
+	vmspace_free(p->p_vmspace);
+}
+
+/*
+ * Dump the machine specific header information at the start of a core dump.
+ */
+int
+cpu_coredump(p, vp, cred)
+	struct proc *p;
+	struct vnode *vp;
+	struct ucred *cred;
+{
+
+	return (vn_rdwr(UIO_WRITE, vp, (caddr_t) p->p_addr, ctob(UPAGES),
+	    (off_t)0, UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred, (int *)NULL,
+	    p));
+}
+
+#ifdef notyet
+static void
+setredzone(pte, vaddr)
+	u_short *pte;
+	caddr_t vaddr;
+{
+/* eventually do this by setting up an expand-down stack segment
+   for ss0: selector, allowing stack access down to top of u.
+   this means though that protection violations need to be handled
+   thru a double fault exception that must do an integral task
+   switch to a known good context, within which a dump can be
+   taken. a sensible scheme might be to save the initial context
+   used by sched (that has physical memory mapped 1:1 at bottom)
+   and take the dump while still in mapped mode */
+}
+#endif
+
+/*
+ * Map an IO request into kernel virtual address space.
+ *
+ * All requests are (re)mapped into kernel VA space.
+ * Notice that we use b_bufsize for the size of the buffer
+ * to be mapped.  b_bcount might be modified by the driver.
+ */
+void
+vmapbuf(bp)
+	register struct buf *bp;
+{
+	register caddr_t addr, v, kva;
+	vm_offset_t pa;
+
+	if ((bp->b_flags & B_PHYS) == 0)
+		panic("vmapbuf");
+
+	for (v = bp->b_saveaddr, addr = (caddr_t)trunc_page(bp->b_data);
+	    addr < bp->b_data + bp->b_bufsize;
+	    addr += PAGE_SIZE, v += PAGE_SIZE) {
+		/*
+		 * Do the vm_fault if needed; do the copy-on-write thing
+		 * when reading stuff off device into memory.
+		 */
+		vm_fault_quick(addr,
+			(bp->b_flags&B_READ)?(VM_PROT_READ|VM_PROT_WRITE):VM_PROT_READ);
+		pa = trunc_page(pmap_kextract((vm_offset_t) addr));
+		if (pa == 0)
+			panic("vmapbuf: page not present");
+		vm_page_hold(PHYS_TO_VM_PAGE(pa));
+		pmap_kenter((vm_offset_t) v, pa);
+	}
+
+	kva = bp->b_saveaddr;
+	bp->b_saveaddr = bp->b_data;
+	bp->b_data = kva + (((vm_offset_t) bp->b_data) & PAGE_MASK);
+}
+
+/*
+ * Free the io map PTEs associated with this IO operation.
+ * We also invalidate the TLB entries and restore the original b_addr.
+ */
+void
+vunmapbuf(bp)
+	register struct buf *bp;
+{
+	register caddr_t addr;
+	vm_offset_t pa;
+
+	if ((bp->b_flags & B_PHYS) == 0)
+		panic("vunmapbuf");
+
+	for (addr = (caddr_t)trunc_page(bp->b_data);
+	    addr < bp->b_data + bp->b_bufsize;
+	    addr += PAGE_SIZE) {
+		pa = trunc_page(pmap_kextract((vm_offset_t) addr));
+		pmap_kremove((vm_offset_t) addr);
+		vm_page_unhold(PHYS_TO_VM_PAGE(pa));
+	}
+
+	bp->b_data = bp->b_saveaddr;
+}
+
+/*
+ * Force reset the processor by invalidating the entire address space!
+ */
+void
+cpu_reset()
+{
+	prom_halt(0);
+}
+
+/*
+ * Grow the user stack to allow for 'sp'. This version grows the stack in
+ *	chunks of SGROWSIZ.
+ */
+int
+grow(p, sp)
+	struct proc *p;
+	size_t sp;
+{
+	unsigned int nss;
+	caddr_t v;
+	struct vmspace *vm = p->p_vmspace;
+
+	if ((caddr_t)sp <= vm->vm_maxsaddr || sp >= (size_t) USRSTACK)
+	    return (1);
+
+	nss = roundup(USRSTACK - (unsigned)sp, PAGE_SIZE);
+
+	if (nss > p->p_rlimit[RLIMIT_STACK].rlim_cur)
+		return (0);
+
+	if (vm->vm_ssize && roundup(vm->vm_ssize << PAGE_SHIFT,
+	    SGROWSIZ) < nss) {
+		int grow_amount;
+		/*
+		 * If necessary, grow the VM that the stack occupies
+		 * to allow for the rlimit. This allows us to not have
+		 * to allocate all of the VM up-front in execve (which
+		 * is expensive).
+		 * Grow the VM by the amount requested rounded up to
+		 * the nearest SGROWSIZ to provide for some hysteresis.
+		 */
+		grow_amount = roundup((nss - (vm->vm_ssize << PAGE_SHIFT)), SGROWSIZ);
+		v = (char *)USRSTACK - roundup(vm->vm_ssize << PAGE_SHIFT,
+		    SGROWSIZ) - grow_amount;
+		/*
+		 * If there isn't enough room to extend by SGROWSIZ, then
+		 * just extend to the maximum size
+		 */
+		if (v < vm->vm_maxsaddr) {
+			v = vm->vm_maxsaddr;
+			grow_amount = MAXSSIZ - (vm->vm_ssize << PAGE_SHIFT);
+		}
+		if ((grow_amount == 0) || (vm_map_find(&vm->vm_map, NULL, 0, (vm_offset_t *)&v,
+		    grow_amount, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0) != KERN_SUCCESS)) {
+			return (0);
+		}
+		vm->vm_ssize += grow_amount >> PAGE_SHIFT;
+	}
+
+	return (1);
+}
+
+static int cnt_prezero;
+
+SYSCTL_INT(_machdep, OID_AUTO, cnt_prezero, CTLFLAG_RD, &cnt_prezero, 0, "");
+
+/*
+ * Implement the pre-zeroed page mechanism.
+ * This routine is called from the idle loop.
+ */
+int
+vm_page_zero_idle()
+{
+	static int free_rover;
+	vm_page_t m;
+	int s;
+
+	/*
+	 * XXX
+	 * We stop zeroing pages when there are sufficent prezeroed pages.
+	 * This threshold isn't really needed, except we want to
+	 * bypass unneeded calls to vm_page_list_find, and the
+	 * associated cache flush and latency.  The pre-zero will
+	 * still be called when there are significantly more
+	 * non-prezeroed pages than zeroed pages.  The threshold
+	 * of half the number of reserved pages is arbitrary, but
+	 * approximately the right amount.  Eventually, we should
+	 * perhaps interrupt the zero operation when a process
+	 * is found to be ready to run.
+	 */
+	if (cnt.v_free_count - vm_page_zero_count <= cnt.v_free_reserved / 2)
+		return (0);
+#ifdef SMP
+	if (try_mplock()) {
+#endif
+		s = splvm();
+		m = vm_page_list_find(PQ_FREE, free_rover);
+		if (m != NULL) {
+			--(*vm_page_queues[m->queue].lcnt);
+			TAILQ_REMOVE(vm_page_queues[m->queue].pl, m, pageq);
+			m->queue = PQ_NONE;
+			splx(s);
+#if 0
+			rel_mplock();
+#endif
+			pmap_zero_page(VM_PAGE_TO_PHYS(m));
+#if 0
+			get_mplock();
+#endif
+			(void)splvm();
+			m->queue = PQ_ZERO + m->pc;
+			++(*vm_page_queues[m->queue].lcnt);
+			TAILQ_INSERT_HEAD(vm_page_queues[m->queue].pl, m,
+			    pageq);
+			free_rover = (free_rover + PQ_PRIME3) & PQ_L2_MASK;
+			++vm_page_zero_count;
+			++cnt_prezero;
+		}
+		splx(s);
+#ifdef SMP
+		rel_mplock();
+#endif
+		return (1);
+#ifdef SMP
+	}
+#endif
+	return (0);
+}
+
+/*
+ * Software interrupt handler for queued VM system processing.
+ */   
+void  
+swi_vm() 
+{     
+#if 0
+	if (busdma_swi_pending != 0)
+		busdma_swi();
+#endif
+}
+
+/*
+ * Tell whether this address is in some physical memory region.
+ * Currently used by the kernel coredump code in order to avoid
+ * dumping the ``ISA memory hole'' which could cause indefinite hangs,
+ * or other unpredictable behaviour.
+ */
+
+
+int
+is_physical_memory(addr)
+	vm_offset_t addr;
+{
+	/*
+	 * stuff other tests for known memory-mapped devices (PCI?)
+	 * here
+	 */
+
+	return 1;
+}
diff --git a/sys/powerpc/powerpc/vm_machdep.c b/sys/powerpc/powerpc/vm_machdep.c
new file mode 100644
index 0000000..89edb49
--- /dev/null
+++ b/sys/powerpc/powerpc/vm_machdep.c
@@ -0,0 +1,516 @@
+/*-
+ * Copyright (c) 1982, 1986 The Regents of the University of California.
+ * Copyright (c) 1989, 1990 William Jolitz
+ * Copyright (c) 1994 John Dyson
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * the Systems Programming Group of the University of Utah Computer
+ * Science Department, and William Jolitz.
+ *
+ * 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.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University 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 THE REGENTS 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 REGENTS 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.
+ *
+ *	from: @(#)vm_machdep.c	7.3 (Berkeley) 5/13/91
+ *	Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
+ *	$Id: vm_machdep.c,v 1.1 1998/06/10 10:53:40 dfr Exp $
+ */
+/*
+ * Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Author: Chris G. Demetriou
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/proc.h>
+#include <sys/malloc.h>
+#include <sys/buf.h>
+#include <sys/vnode.h>
+#include <sys/vmmeter.h>
+#include <sys/kernel.h>
+#include <sys/sysctl.h>
+
+#include <machine/clock.h>
+#include <machine/cpu.h>
+#include <machine/md_var.h>
+#include <machine/prom.h>
+
+#include <vm/vm.h>
+#include <vm/vm_param.h>
+#include <vm/vm_prot.h>
+#include <sys/lock.h>
+#include <vm/vm_kern.h>
+#include <vm/vm_page.h>
+#include <vm/vm_map.h>
+#include <vm/vm_extern.h>
+
+#include <sys/user.h>
+
+/*
+ * quick version of vm_fault
+ */
+void
+vm_fault_quick(v, prot)
+	caddr_t v;
+	int prot;
+{
+	if (prot & VM_PROT_WRITE)
+		subyte(v, fubyte(v));
+	else
+		fubyte(v);
+}
+
+/*
+ * Finish a fork operation, with process p2 nearly set up.
+ * Copy and update the pcb, set up the stack so that the child
+ * ready to run and return to user mode.
+ */
+void
+cpu_fork(p1, p2)
+	register struct proc *p1, *p2;
+{
+	struct user *up = p2->p_addr;
+	int i;
+
+	p2->p_md.md_tf = p1->p_md.md_tf;
+	p2->p_md.md_flags = p1->p_md.md_flags & MDP_FPUSED;
+
+	/*
+	 * Cache the physical address of the pcb, so we can
+	 * swap to it easily.
+	 */
+	p2->p_md.md_pcbpaddr = (void*) vtophys((vm_offset_t) &up->u_pcb);
+
+	/*
+	 * Simulate a write to the process's U-area pages,
+	 * so that the system doesn't lose badly.
+	 * (If this isn't done, the kernel can't read or
+	 * write the kernel stack.  "Ouch!")
+	 */
+	for (i = 0; i < UPAGES; i++)
+		pmap_emulate_reference(p2, (vm_offset_t)up + i * PAGE_SIZE,
+		    0, 1);
+
+	/*
+	 * Copy floating point state from the FP chip to the PCB
+	 * if this process has state stored there.
+	 */
+	if (p1 == fpcurproc) {
+		alpha_pal_wrfen(1);
+		savefpstate(&fpcurproc->p_addr->u_pcb.pcb_fp);
+		alpha_pal_wrfen(0);
+	}
+
+	/*
+	 * Copy pcb and stack from proc p1 to p2.
+	 * We do this as cheaply as possible, copying only the active
+	 * part of the stack.  The stack and pcb need to agree;
+	 */
+	p2->p_addr->u_pcb = p1->p_addr->u_pcb;
+	p2->p_addr->u_pcb.pcb_hw.apcb_usp = alpha_pal_rdusp();
+
+	/*
+	 * Arrange for a non-local goto when the new process
+	 * is started, to resume here, returning nonzero from setjmp.
+	 */
+#ifdef DIAGNOSTIC
+	if (p1 != curproc)
+		panic("cpu_fork: curproc");
+	if ((up->u_pcb.pcb_hw.apcb_flags & ALPHA_PCB_FLAGS_FEN) != 0)
+		printf("DANGER WILL ROBINSON: FEN SET IN cpu_fork!\n");
+#endif
+
+	/*
+	 * create the child's kernel stack, from scratch.
+	 */
+	{
+		struct trapframe *p2tf;
+
+		/*
+		 * Pick a stack pointer, leaving room for a trapframe;
+		 * copy trapframe from parent so return to user mode
+		 * will be to right address, with correct registers.
+		 */
+		p2tf = p2->p_md.md_tf = (struct trapframe *)
+		    ((char *)p2->p_addr + USPACE - sizeof(struct trapframe));
+		bcopy(p1->p_md.md_tf, p2->p_md.md_tf,
+		    sizeof(struct trapframe));
+
+		/*
+		 * Set up return-value registers as fork() libc stub expects.
+		 */
+		p2tf->tf_regs[FRAME_V0] = p1->p_pid;	/* parent's pid */
+		p2tf->tf_regs[FRAME_A3] = 0;		/* no error */
+		p2tf->tf_regs[FRAME_A4] = 1;		/* is child */
+
+		/*
+		 * Arrange for continuation at child_return(), which
+		 * will return to exception_return().  Note that the child
+		 * process doesn't stay in the kernel for long!
+		 * 
+		 * This is an inlined version of cpu_set_kpc.
+		 */
+		up->u_pcb.pcb_hw.apcb_ksp = (u_int64_t)p2tf;	
+		up->u_pcb.pcb_context[0] =
+		    (u_int64_t)child_return;		/* s0: pc */
+		up->u_pcb.pcb_context[1] =
+		    (u_int64_t)exception_return;	/* s1: ra */
+		up->u_pcb.pcb_context[2] = (u_long) p2;	/* s2: a0 */
+		up->u_pcb.pcb_context[7] =
+		    (u_int64_t)switch_trampoline;	/* ra: assembly magic */
+	}
+}
+
+/*
+ * Intercept the return address from a freshly forked process that has NOT
+ * been scheduled yet.
+ *
+ * This is needed to make kernel threads stay in kernel mode.
+ */
+void
+cpu_set_fork_handler(p, func, arg)
+	struct proc *p;
+	void (*func) __P((void *));
+	void *arg;
+{
+	/*
+	 * Note that the trap frame follows the args, so the function
+	 * is really called like this:  func(arg, frame);
+	 */
+	p->p_addr->u_pcb.pcb_context[0] = (u_long) func;
+	p->p_addr->u_pcb.pcb_context[2] = (u_long) arg;
+}
+
+/*
+ * cpu_exit is called as the last action during exit.
+ * We release the address space of the process, block interrupts,
+ * and call switch_exit.  switch_exit switches to proc0's PCB and stack,
+ * then jumps into the middle of cpu_switch, as if it were switching
+ * from proc0.
+ */
+void
+cpu_exit(p)
+	register struct proc *p;
+{
+	if (p == fpcurproc)
+		fpcurproc = NULL;
+
+	(void) splhigh();
+	cnt.v_swtch++;
+	cpu_switch(p);
+	panic("cpu_exit");
+}
+
+void
+cpu_wait(p)
+	struct proc *p;
+{
+	/* drop per-process resources */
+	pmap_dispose_proc(p);
+
+	/* and clean-out the vmspace */
+	vmspace_free(p->p_vmspace);
+}
+
+/*
+ * Dump the machine specific header information at the start of a core dump.
+ */
+int
+cpu_coredump(p, vp, cred)
+	struct proc *p;
+	struct vnode *vp;
+	struct ucred *cred;
+{
+
+	return (vn_rdwr(UIO_WRITE, vp, (caddr_t) p->p_addr, ctob(UPAGES),
+	    (off_t)0, UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred, (int *)NULL,
+	    p));
+}
+
+#ifdef notyet
+static void
+setredzone(pte, vaddr)
+	u_short *pte;
+	caddr_t vaddr;
+{
+/* eventually do this by setting up an expand-down stack segment
+   for ss0: selector, allowing stack access down to top of u.
+   this means though that protection violations need to be handled
+   thru a double fault exception that must do an integral task
+   switch to a known good context, within which a dump can be
+   taken. a sensible scheme might be to save the initial context
+   used by sched (that has physical memory mapped 1:1 at bottom)
+   and take the dump while still in mapped mode */
+}
+#endif
+
+/*
+ * Map an IO request into kernel virtual address space.
+ *
+ * All requests are (re)mapped into kernel VA space.
+ * Notice that we use b_bufsize for the size of the buffer
+ * to be mapped.  b_bcount might be modified by the driver.
+ */
+void
+vmapbuf(bp)
+	register struct buf *bp;
+{
+	register caddr_t addr, v, kva;
+	vm_offset_t pa;
+
+	if ((bp->b_flags & B_PHYS) == 0)
+		panic("vmapbuf");
+
+	for (v = bp->b_saveaddr, addr = (caddr_t)trunc_page(bp->b_data);
+	    addr < bp->b_data + bp->b_bufsize;
+	    addr += PAGE_SIZE, v += PAGE_SIZE) {
+		/*
+		 * Do the vm_fault if needed; do the copy-on-write thing
+		 * when reading stuff off device into memory.
+		 */
+		vm_fault_quick(addr,
+			(bp->b_flags&B_READ)?(VM_PROT_READ|VM_PROT_WRITE):VM_PROT_READ);
+		pa = trunc_page(pmap_kextract((vm_offset_t) addr));
+		if (pa == 0)
+			panic("vmapbuf: page not present");
+		vm_page_hold(PHYS_TO_VM_PAGE(pa));
+		pmap_kenter((vm_offset_t) v, pa);
+	}
+
+	kva = bp->b_saveaddr;
+	bp->b_saveaddr = bp->b_data;
+	bp->b_data = kva + (((vm_offset_t) bp->b_data) & PAGE_MASK);
+}
+
+/*
+ * Free the io map PTEs associated with this IO operation.
+ * We also invalidate the TLB entries and restore the original b_addr.
+ */
+void
+vunmapbuf(bp)
+	register struct buf *bp;
+{
+	register caddr_t addr;
+	vm_offset_t pa;
+
+	if ((bp->b_flags & B_PHYS) == 0)
+		panic("vunmapbuf");
+
+	for (addr = (caddr_t)trunc_page(bp->b_data);
+	    addr < bp->b_data + bp->b_bufsize;
+	    addr += PAGE_SIZE) {
+		pa = trunc_page(pmap_kextract((vm_offset_t) addr));
+		pmap_kremove((vm_offset_t) addr);
+		vm_page_unhold(PHYS_TO_VM_PAGE(pa));
+	}
+
+	bp->b_data = bp->b_saveaddr;
+}
+
+/*
+ * Force reset the processor by invalidating the entire address space!
+ */
+void
+cpu_reset()
+{
+	prom_halt(0);
+}
+
+/*
+ * Grow the user stack to allow for 'sp'. This version grows the stack in
+ *	chunks of SGROWSIZ.
+ */
+int
+grow(p, sp)
+	struct proc *p;
+	size_t sp;
+{
+	unsigned int nss;
+	caddr_t v;
+	struct vmspace *vm = p->p_vmspace;
+
+	if ((caddr_t)sp <= vm->vm_maxsaddr || sp >= (size_t) USRSTACK)
+	    return (1);
+
+	nss = roundup(USRSTACK - (unsigned)sp, PAGE_SIZE);
+
+	if (nss > p->p_rlimit[RLIMIT_STACK].rlim_cur)
+		return (0);
+
+	if (vm->vm_ssize && roundup(vm->vm_ssize << PAGE_SHIFT,
+	    SGROWSIZ) < nss) {
+		int grow_amount;
+		/*
+		 * If necessary, grow the VM that the stack occupies
+		 * to allow for the rlimit. This allows us to not have
+		 * to allocate all of the VM up-front in execve (which
+		 * is expensive).
+		 * Grow the VM by the amount requested rounded up to
+		 * the nearest SGROWSIZ to provide for some hysteresis.
+		 */
+		grow_amount = roundup((nss - (vm->vm_ssize << PAGE_SHIFT)), SGROWSIZ);
+		v = (char *)USRSTACK - roundup(vm->vm_ssize << PAGE_SHIFT,
+		    SGROWSIZ) - grow_amount;
+		/*
+		 * If there isn't enough room to extend by SGROWSIZ, then
+		 * just extend to the maximum size
+		 */
+		if (v < vm->vm_maxsaddr) {
+			v = vm->vm_maxsaddr;
+			grow_amount = MAXSSIZ - (vm->vm_ssize << PAGE_SHIFT);
+		}
+		if ((grow_amount == 0) || (vm_map_find(&vm->vm_map, NULL, 0, (vm_offset_t *)&v,
+		    grow_amount, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0) != KERN_SUCCESS)) {
+			return (0);
+		}
+		vm->vm_ssize += grow_amount >> PAGE_SHIFT;
+	}
+
+	return (1);
+}
+
+static int cnt_prezero;
+
+SYSCTL_INT(_machdep, OID_AUTO, cnt_prezero, CTLFLAG_RD, &cnt_prezero, 0, "");
+
+/*
+ * Implement the pre-zeroed page mechanism.
+ * This routine is called from the idle loop.
+ */
+int
+vm_page_zero_idle()
+{
+	static int free_rover;
+	vm_page_t m;
+	int s;
+
+	/*
+	 * XXX
+	 * We stop zeroing pages when there are sufficent prezeroed pages.
+	 * This threshold isn't really needed, except we want to
+	 * bypass unneeded calls to vm_page_list_find, and the
+	 * associated cache flush and latency.  The pre-zero will
+	 * still be called when there are significantly more
+	 * non-prezeroed pages than zeroed pages.  The threshold
+	 * of half the number of reserved pages is arbitrary, but
+	 * approximately the right amount.  Eventually, we should
+	 * perhaps interrupt the zero operation when a process
+	 * is found to be ready to run.
+	 */
+	if (cnt.v_free_count - vm_page_zero_count <= cnt.v_free_reserved / 2)
+		return (0);
+#ifdef SMP
+	if (try_mplock()) {
+#endif
+		s = splvm();
+		m = vm_page_list_find(PQ_FREE, free_rover);
+		if (m != NULL) {
+			--(*vm_page_queues[m->queue].lcnt);
+			TAILQ_REMOVE(vm_page_queues[m->queue].pl, m, pageq);
+			m->queue = PQ_NONE;
+			splx(s);
+#if 0
+			rel_mplock();
+#endif
+			pmap_zero_page(VM_PAGE_TO_PHYS(m));
+#if 0
+			get_mplock();
+#endif
+			(void)splvm();
+			m->queue = PQ_ZERO + m->pc;
+			++(*vm_page_queues[m->queue].lcnt);
+			TAILQ_INSERT_HEAD(vm_page_queues[m->queue].pl, m,
+			    pageq);
+			free_rover = (free_rover + PQ_PRIME3) & PQ_L2_MASK;
+			++vm_page_zero_count;
+			++cnt_prezero;
+		}
+		splx(s);
+#ifdef SMP
+		rel_mplock();
+#endif
+		return (1);
+#ifdef SMP
+	}
+#endif
+	return (0);
+}
+
+/*
+ * Software interrupt handler for queued VM system processing.
+ */   
+void  
+swi_vm() 
+{     
+#if 0
+	if (busdma_swi_pending != 0)
+		busdma_swi();
+#endif
+}
+
+/*
+ * Tell whether this address is in some physical memory region.
+ * Currently used by the kernel coredump code in order to avoid
+ * dumping the ``ISA memory hole'' which could cause indefinite hangs,
+ * or other unpredictable behaviour.
+ */
+
+
+int
+is_physical_memory(addr)
+	vm_offset_t addr;
+{
+	/*
+	 * stuff other tests for known memory-mapped devices (PCI?)
+	 * here
+	 */
+
+	return 1;
+}