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Rather than starting init and creating kthreads by forking and then
doing a cpu_set_kpc(), just pass the entry point and argument all
the way down the fork path starting with fork1().  In order to
avoid special-casing the normal fork in every cpu_fork(), MI code
passes down child_return() and the child process pointer explicitly.

This fixes a race condition on multiprocessor systems; a CPU could
grab the newly created processes (which has been placed on a run queue)
before cpu_set_kpc() would be performed.

/*	$NetBSD: vm_machdep.c,v 1.9 2000/05/28 05:49:03 thorpej Exp $	*/

/*-
 * Copyright (c) 1995 Charles M. Hannum.  All rights reserved.
 * Copyright (c) 1982, 1986 The Regents of the University of California.
 * Copyright (c) 1989, 1990 William Jolitz
 * 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.
 *
 *	@(#)vm_machdep.c	7.3 (Berkeley) 5/13/91
 */

/*
 *	Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <sys/buf.h>
#include <sys/user.h>
#include <sys/core.h>
#include <sys/exec.h>
#include <sys/ptrace.h>

#include <vm/vm.h>
#include <vm/vm_kern.h>

#include <machine/cpu.h>
#include <machine/reg.h>

void	setredzone __P((u_short *, caddr_t));

/*
 * Finish a fork operation, with process p2 nearly set up.
 * Copy and update the pcb and trap frame, making the child ready to run.
 * 
 * Rig the child's kernel stack so that it will start out in
 * proc_trampoline() and call child_return() with p2 as an
 * argument. This causes the newly-created child process to go
 * directly to user level with an apparent return value of 0 from
 * fork(), while the parent process returns normally.
 *
 * p1 is the process being forked; if p1 == &proc0, we are creating
 * a kernel thread, and the return path and argument are specified with
 * `func' and `arg'.
 *
 * If an alternate user-level stack is requested (with non-zero values
 * in both the stack and stacksize args), set up the user stack pointer
 * accordingly.
 */
void
cpu_fork(p1, p2, stack, stacksize, func, arg)
	register struct proc *p1, *p2;
	void *stack;
	size_t stacksize;
	void (*func) __P((void *));
	void *arg;
{
	register struct pcb *pcb = &p2->p_addr->u_pcb;
	register struct trapframe *tf;
	register struct switchframe *sf;

#ifdef sh3_debug
	printf("cpu_fork:p1(%p),p2(%p)\n", p1, p2);
#endif

	p2->p_md.md_flags = p1->p_md.md_flags;

	/* Copy pcb from proc p1 to p2. */
	if (p1 == curproc) {
		/* Sync the PCB before we copy it. */
		savectx(curpcb);
	}
#ifdef DIAGNOSTIC
	else if (p1 != &proc0)
		panic("cpu_fork: curproc");
#endif
	*pcb = p1->p_addr->u_pcb;
	pmap_activate(p2);

	/* set up the kernel stack pointer */
	pcb->kr15 = (int)p2->p_addr + USPACE - sizeof(struct trapframe);

	/*
	 * Copy the trapframe.
	 */
	p2->p_md.md_regs = tf = (struct trapframe *)pcb->kr15 - 1;
	*tf = *p1->p_md.md_regs;

	/*
	 * If specified, give the child a different stack.
	 */
	if (stack != NULL)
		tf->tf_r15 = (u_int)stack + stacksize;

	sf = (struct switchframe *)tf - 1;
	sf->sf_ppl = 0;
	sf->sf_r12 = (int)func;
	sf->sf_r11 = (int)arg;
	sf->sf_pr = (int)proc_trampoline;
	pcb->r15 = (int)sf;

	/* convert r15, kr15 to physical address , because tlb miss must not
	   be occured when accessing kernel stack */
	pcb->r15 = vtophys(pcb->r15);
	pcb->kr15 = vtophys(pcb->kr15);
}

void
cpu_swapout(p)
	struct proc *p;
{

}

/*
 * cpu_exit is called as the last action during exit.
 *
 * We clean up a little and then call switch_exit() with the old proc as an
 * argument.  switch_exit() first switches to proc0's context, and finally
 * jumps into switch() to wait for another process to wake up.
 */
void
cpu_exit(p)
	register struct proc *p;
{
	uvmexp.swtch++;
	switch_exit(p);
}

/*
 * Dump the machine specific segment at the start of a core dump.
 */
struct md_core {
	struct reg intreg;
};

int
cpu_coredump(p, vp, cred, chdr)
	struct proc *p;
	struct vnode *vp;
	struct ucred *cred;
	struct core *chdr;
{
	struct md_core md_core;
	struct coreseg cseg;
	int error;

	CORE_SETMAGIC(*chdr, COREMAGIC, MID_MACHINE, 0);
	chdr->c_hdrsize = ALIGN(sizeof(*chdr));
	chdr->c_seghdrsize = ALIGN(sizeof(cseg));
	chdr->c_cpusize = sizeof(md_core);

	/* Save integer registers. */
	error = process_read_regs(p, &md_core.intreg);
	if (error)
		return error;


	CORE_SETMAGIC(cseg, CORESEGMAGIC, MID_MACHINE, CORE_CPU);
	cseg.c_addr = 0;
	cseg.c_size = chdr->c_cpusize;

	error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&cseg, chdr->c_seghdrsize,
	    (off_t)chdr->c_hdrsize, UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred,
	    (int *)0, p);
	if (error)
		return error;

	error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&md_core, sizeof(md_core),
	    (off_t)(chdr->c_hdrsize + chdr->c_seghdrsize), UIO_SYSSPACE,
	    IO_NODELOCKED|IO_UNIT, cred, (int *)0, p);
	if (error)
		return error;

	chdr->c_nseg++;
	return 0;
}

#if 0
/*
 * Set a red zone in the kernel stack after the u. area.
 */
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

/*
 * Move pages from one kernel virtual address to another.
 * Both addresses are assumed to reside in the Sysmap,
 * and size must be a multiple of CLSIZE.
 */
void
pagemove(from, to, size)
	register caddr_t from, to;
	size_t size;
{
	register pt_entry_t *fpte, *tpte;

	if (size % NBPG)
		panic("pagemove");
	fpte = kvtopte(from);
	tpte = kvtopte(to);
	while (size > 0) {
		*tpte++ = *fpte;
		*fpte++ = 0;
		from += NBPG;
		to += NBPG;
		size -= NBPG;
	}
	pmap_update();
}

extern vm_map_t phys_map;

/*
 * Map an IO request into kernel virtual address space.  Requests fall into
 * one of five catagories:
 *
 *	B_PHYS|B_UAREA:	User u-area swap.
 *			Address is relative to start of u-area (p_addr).
 *	B_PHYS|B_PAGET:	User page table swap.
 *			Address is a kernel VA in usrpt (Usrptmap).
 *	B_PHYS|B_DIRTY:	Dirty page push.
 *			Address is a VA in proc2's address space.
 *	B_PHYS|B_PGIN:	Kernel pagein of user pages.
 *			Address is VA in user's address space.
 *	B_PHYS:		User "raw" IO request.
 *			Address is VA in user's address space.
 *
 * All requests are (re)mapped into kernel VA space via the phys_map
 * (a name with only slightly more meaning than "kernel_map")
 */

void
vmapbuf(bp, len)
	struct buf *bp;
	vsize_t len;
{
	vaddr_t faddr, taddr, off;
	paddr_t fpa;

	if ((bp->b_flags & B_PHYS) == 0)
		panic("vmapbuf");
	faddr = trunc_page((vaddr_t)bp->b_saveaddr = bp->b_data);
	off = (vaddr_t)bp->b_data - faddr;
	len = round_page(off + len);
	taddr= uvm_km_valloc_wait(phys_map, len);
	bp->b_data = (caddr_t)(taddr + off);
	/*
	 * The region is locked, so we expect that pmap_pte() will return
	 * non-NULL.
	 * XXX: unwise to expect this in a multithreaded environment.
	 * anything can happen to a pmap between the time we lock a 
	 * region, release the pmap lock, and then relock it for
	 * the pmap_extract().
	 *
	 * no need to flush TLB since we expect nothing to be mapped
	 * where we we just allocated (TLB will be flushed when our
	 * mapping is removed).
	 */
	while (len) {
		pmap_extract(vm_map_pmap(&bp->b_proc->p_vmspace->vm_map),
			     faddr, &fpa);
		pmap_enter(vm_map_pmap(phys_map), taddr, fpa,
			   VM_PROT_READ|VM_PROT_WRITE, PMAP_WIRED);
		faddr += PAGE_SIZE;
		taddr += PAGE_SIZE;
		len -= PAGE_SIZE;
	}
}

/*
 * 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, len)
	struct buf *bp;
	vsize_t len;
{
	vaddr_t addr, off;

	if ((bp->b_flags & B_PHYS) == 0)
		panic("vunmapbuf");
	addr = trunc_page((vaddr_t)bp->b_data);
	off = (vaddr_t)bp->b_data - addr;
	len = round_page(off + len);
	uvm_km_free_wakeup(phys_map, addr, len);
	bp->b_data = bp->b_saveaddr;
	bp->b_saveaddr = 0;
}