/*	$OpenBSD: vm_machdep.c,v 1.15 2015/05/05 02:13:46 guenther Exp $	*/
/*	$NetBSD: vm_machdep.c,v 1.31 2004/01/04 11:33:29 jdolecek Exp $	*/

/*
 * Copyright (c) 1994-1998 Mark Brinicombe.
 * Copyright (c) 1994 Brini.
 * All rights reserved.
 *
 * This code is derived from software written for Brini by Mark Brinicombe
 *
 * 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 Brini.
 * 4. The name of the company nor the name of the author may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY BRINI ``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 BRINI 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.
 *
 * RiscBSD kernel project
 *
 * vm_machdep.h
 *
 * vm machine specific bits
 *
 * Created      : 08/10/94
 */

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

#include <uvm/uvm_extern.h>

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

extern pv_addr_t systempage;

int process_read_regs	(struct proc *p, struct reg *regs);
int process_read_fpregs	(struct proc *p, struct fpreg *regs);

extern void proc_trampoline	(void);

/*
 * Special compilation symbols:
 *
 * STACKCHECKS - Fill undefined and supervisor stacks with a known pattern
 *		 on forking and check the pattern on exit, reporting
 *		 the amount of stack used.
 */

/*
 * 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)
	struct proc *p1;
	struct proc *p2;
	void *stack;
	size_t stacksize;
	void (*func) (void *);
	void *arg;
{
	struct pcb *pcb = (struct pcb *)&p2->p_addr->u_pcb;
	struct trapframe *tf;
	struct switchframe *sf;

#ifdef PMAP_DEBUG
	if (pmap_debug_level >= 0)
		printf("cpu_fork: %p %p %p\n", p1, p2, &proc0);
#endif	/* PMAP_DEBUG */

	if (p1 == curproc) {
		/* Sync the PCB before we copy it. */
		savectx(curpcb);
	}

	/* Copy the pcb */
	*pcb = p1->p_addr->u_pcb;

	/* 
	 * Set up the undefined stack for the process.
	 * Note: this stack is not in use if we are forking from p1
	 */
	pcb->pcb_un.un_32.pcb32_und_sp = (u_int)p2->p_addr +
	    USPACE_UNDEF_STACK_TOP;
	pcb->pcb_un.un_32.pcb32_sp = (u_int)p2->p_addr + USPACE_SVC_STACK_TOP;

#ifdef STACKCHECKS
	/* Fill the undefined stack with a known pattern */
	memset(((u_char *)p2->p_addr) + USPACE_UNDEF_STACK_BOTTOM, 0xdd,
	    (USPACE_UNDEF_STACK_TOP - USPACE_UNDEF_STACK_BOTTOM));
	/* Fill the kernel stack with a known pattern */
	memset(((u_char *)p2->p_addr) + USPACE_SVC_STACK_BOTTOM, 0xdd,
	    (USPACE_SVC_STACK_TOP - USPACE_SVC_STACK_BOTTOM));
#endif	/* STACKCHECKS */

#ifdef PMAP_DEBUG
	if (pmap_debug_level >= 0) {
		printf("p1->procaddr=%p p1->procaddr->u_pcb=%p pid=%d pmap=%p\n",
		    p1->p_addr, &p1->p_addr->u_pcb, p1->p_pid,
		    p1->p_vmspace->vm_map.pmap);
		printf("p2->procaddr=%p p2->procaddr->u_pcb=%p pid=%d pmap=%p\n",
		    p2->p_addr, &p2->p_addr->u_pcb, p2->p_pid,
		    p2->p_vmspace->vm_map.pmap);
	}
#endif	/* PMAP_DEBUG */

	pmap_activate(p2);

	p2->p_addr->u_pcb.pcb_tf = tf =
	    (struct trapframe *)pcb->pcb_un.un_32.pcb32_sp - 1;
	*tf = *p1->p_addr->u_pcb.pcb_tf;

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

	sf = (struct switchframe *)tf - 1;
	sf->sf_r4 = (u_int)func;
	sf->sf_r5 = (u_int)arg;
	sf->sf_pc = (u_int)proc_trampoline;
	pcb->pcb_un.un_32.pcb32_sp = (u_int)sf;
}

void
cpu_exit(struct proc *p)
{
	pmap_deactivate(p);
	sched_exit(p);
}

/*
 * Map a user I/O request into kernel virtual address space.
 * Note: the pages are already locked by uvm_vslock(), so we
 * do not need to pass an access_type to pmap_enter().
 */
void
vmapbuf(bp, len)
	struct buf *bp;
	vsize_t len;
{
	vaddr_t faddr, taddr, off;
	paddr_t fpa;


#ifdef PMAP_DEBUG
	if (pmap_debug_level >= 0)
		printf("vmapbuf: bp=%08x buf=%08x len=%08x\n", (u_int)bp,
		    (u_int)bp->b_data, (u_int)len);
#endif	/* PMAP_DEBUG */
    
	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.
	 */
	while (len) {
		(void) pmap_extract(vm_map_pmap(&bp->b_proc->p_vmspace->vm_map),
		    faddr, &fpa);
		pmap_enter(pmap_kernel(), taddr, fpa,
		    PROT_READ | PROT_WRITE,
		    PROT_READ | PROT_WRITE | PMAP_WIRED);
		faddr += PAGE_SIZE;
		taddr += PAGE_SIZE;
		len -= PAGE_SIZE;
	}
	pmap_update(pmap_kernel());
}

/*
 * Unmap a previously-mapped user I/O request.
 */
void
vunmapbuf(bp, len)
	struct buf *bp;
	vsize_t len;
{
	vaddr_t addr, off;

#ifdef PMAP_DEBUG
	if (pmap_debug_level >= 0)
		printf("vunmapbuf: bp=%08x buf=%08x len=%08x\n",
		    (u_int)bp, (u_int)bp->b_data, (u_int)len);
#endif	/* PMAP_DEBUG */

	if ((bp->b_flags & B_PHYS) == 0)
		panic("vunmapbuf");

	/*
	 * Make sure the cache does not have dirty data for the
	 * pages we had mapped.
	 */
	addr = trunc_page((vaddr_t)bp->b_data);
	off = (vaddr_t)bp->b_data - addr;
	len = round_page(off + len);
	
	pmap_remove(pmap_kernel(), addr, addr + len);
	pmap_update(pmap_kernel());
	uvm_km_free_wakeup(phys_map, addr, len);
	bp->b_data = bp->b_saveaddr;
	bp->b_saveaddr = 0;
}

/* End of vm_machdep.c */
