xref: /freebsd-11.0-release/sys/amd64/amd64/machdep.c

/*-
 * Copyright (c) 1992 Terrence R. Lambert.
 * Copyright (c) 1982, 1987, 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * 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: @(#)machdep.c	7.4 (Berkeley) 6/3/91
 *	$Id: machdep.c,v 1.107 1995/02/10 07:44:03 davidg Exp $
 */

#include "npx.h"
#include "isa.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/buf.h>
#include <sys/reboot.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/msgbuf.h>
#include <sys/ioctl.h>
#include <sys/sysent.h>
#include <sys/tty.h>
#include <sys/sysctl.h>

#ifdef SYSVSHM
#include <sys/shm.h>
#endif

#ifdef SYSVMSG
#include <sys/msg.h>
#endif

#ifdef SYSVSEM
#include <sys/sem.h>
#endif

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

#include <sys/exec.h>
#include <sys/vnode.h>

#include <net/netisr.h>

extern vm_offset_t avail_start, avail_end;

#include "ether.h"

#include <machine/cpu.h>
#include <machine/npx.h>
#include <machine/reg.h>
#include <machine/psl.h>
#include <machine/clock.h>
#include <machine/specialreg.h>
#include <machine/sysarch.h>
#include <machine/cons.h>
#include <machine/devconf.h>
#include <machine/bootinfo.h>

#include <i386/isa/isa.h>
#include <i386/isa/isa_device.h>
#include <i386/isa/rtc.h>

static void identifycpu(void);
static void initcpu(void);

char machine[] = "i386";
char cpu_model[sizeof("Cy486DLC") + 1];

#ifndef PANIC_REBOOT_WAIT_TIME
#define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
#endif

/*
 * Declare these as initialized data so we can patch them.
 */
int	nswbuf = 0;
#ifdef	NBUF
int	nbuf = NBUF;
#else
int	nbuf = 0;
#endif

#ifdef BOUNCE_BUFFERS
extern char *bouncememory;
extern int maxbkva;
#ifdef BOUNCEPAGES
int	bouncepages = BOUNCEPAGES;
#else
int	bouncepages = 0;
#endif
#endif	/* BOUNCE_BUFFERS */

extern int freebufspace;
int	msgbufmapped = 0;		/* set when safe to use msgbuf */
int _udatasel, _ucodesel;


/*
 * Machine-dependent startup code
 */
int boothowto = 0, bootverbose = 0, Maxmem = 0, badpages = 0, physmem = 0;
long dumplo;
extern int bootdev;
int biosmem;

vm_offset_t	phys_avail[6];

int cpu_class;

void dumpsys __P((void));
vm_offset_t buffer_sva, buffer_eva;
vm_offset_t clean_sva, clean_eva;
vm_offset_t pager_sva, pager_eva;
extern int pager_map_size;

#define offsetof(type, member)	((size_t)(&((type *)0)->member))

void
cpu_startup()
{
	register unsigned i;
	register caddr_t v;
	extern void (*netisrs[32])(void);
	vm_offset_t maxaddr;
	vm_size_t size = 0;
	int firstaddr;
	vm_offset_t minaddr;

	if (boothowto & RB_VERBOSE)
		bootverbose++;

	/*
	 * Initialize error message buffer (at end of core).
	 */

	/* avail_end was pre-decremented in init_386() to compensate */
	for (i = 0; i < btoc(sizeof (struct msgbuf)); i++)
		pmap_enter(pmap_kernel(), (vm_offset_t)msgbufp,
			   avail_end + i * NBPG,
			   VM_PROT_ALL, TRUE);
	msgbufmapped = 1;

	/*
	 * Good {morning,afternoon,evening,night}.
	 */
	printf(version);
	startrtclock();
	identifycpu();
	printf("real memory  = %d (%d pages)\n", ptoa(physmem), physmem);
	if (badpages)
		printf("bad memory   = %d (%d pages)\n", ptoa(badpages), badpages);

	/*
	 * Quickly wire in netisrs.
	 */
#define DONET(isr, n) do { extern void isr(void); netisrs[n] = isr; } while(0)
#ifdef INET
#if NETHER > 0
	DONET(arpintr, NETISR_ARP);
#endif
	DONET(ipintr, NETISR_IP);
#endif
#ifdef NS
	DONET(nsintr, NETISR_NS);
#endif
#ifdef ISO
	DONET(clnlintr, NETISR_ISO);
#endif
#ifdef CCITT
	DONET(ccittintr, NETISR_CCITT);
#endif
#ifdef ISDN
	DONET(isdnintr, NETISR_ISDN);
#endif
#undef DONET

	/*
	 * Allocate space for system data structures.
	 * The first available kernel virtual address is in "v".
	 * As pages of kernel virtual memory are allocated, "v" is incremented.
	 * As pages of memory are allocated and cleared,
	 * "firstaddr" is incremented.
	 * An index into the kernel page table corresponding to the
	 * virtual memory address maintained in "v" is kept in "mapaddr".
	 */

	/*
	 * Make two passes.  The first pass calculates how much memory is
	 * needed and allocates it.  The second pass assigns virtual
	 * addresses to the various data structures.
	 */
	firstaddr = 0;
again:
	v = (caddr_t)firstaddr;

#define	valloc(name, type, num) \
	    (name) = (type *)v; v = (caddr_t)((name)+(num))
#define	valloclim(name, type, num, lim) \
	    (name) = (type *)v; v = (caddr_t)((lim) = ((name)+(num)))
	valloc(callout, struct callout, ncallout);
#ifdef SYSVSHM
	valloc(shmsegs, struct shmid_ds, shminfo.shmmni);
#endif
#ifdef SYSVSEM
	valloc(sema, struct semid_ds, seminfo.semmni);
	valloc(sem, struct sem, seminfo.semmns);
	/* This is pretty disgusting! */
	valloc(semu, int, (seminfo.semmnu * seminfo.semusz) / sizeof(int));
#endif
#ifdef SYSVMSG
	valloc(msgpool, char, msginfo.msgmax);
	valloc(msgmaps, struct msgmap, msginfo.msgseg);
	valloc(msghdrs, struct msg, msginfo.msgtql);
	valloc(msqids, struct msqid_ds, msginfo.msgmni);
#endif

	if (nbuf == 0) {
		nbuf = 32;
		if( physmem > 1024)
			nbuf += min((physmem - 1024) / 20, 1024);
	}
	nswbuf = min(nbuf, 128);

	valloc(swbuf, struct buf, nswbuf);
	valloc(buf, struct buf, nbuf);

#ifdef BOUNCE_BUFFERS
	/*
	 * If there is more than 16MB of memory, allocate some bounce buffers
	 */
	if (Maxmem > 4096) {
		if (bouncepages == 0) {
			bouncepages = 64;
			bouncepages += ((Maxmem - 4096) / 2048) * 32;
		}
		v = (caddr_t)((vm_offset_t)((vm_offset_t)v + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1));
		valloc(bouncememory, char, bouncepages * PAGE_SIZE);
	}
#endif

	/*
	 * End of first pass, size has been calculated so allocate memory
	 */
	if (firstaddr == 0) {
		size = (vm_size_t)(v - firstaddr);
		firstaddr = (int)kmem_alloc(kernel_map, round_page(size));
		if (firstaddr == 0)
			panic("startup: no room for tables");
		goto again;
	}

	/*
	 * End of second pass, addresses have been assigned
	 */
	if ((vm_size_t)(v - firstaddr) != size)
		panic("startup: table size inconsistency");

#ifdef BOUNCE_BUFFERS
	clean_map = kmem_suballoc(kernel_map, &clean_sva, &clean_eva,
			(nbuf*MAXBSIZE) + (nswbuf*MAXPHYS) +
				maxbkva + pager_map_size, TRUE);
	io_map = kmem_suballoc(clean_map, &minaddr, &maxaddr, maxbkva, FALSE);
#else
	clean_map = kmem_suballoc(kernel_map, &clean_sva, &clean_eva,
			(nbuf*MAXBSIZE) + (nswbuf*MAXPHYS) + pager_map_size, TRUE);
#endif
	buffer_map = kmem_suballoc(clean_map, &buffer_sva, &buffer_eva,
				(nbuf*MAXBSIZE), TRUE);
	pager_map = kmem_suballoc(clean_map, &pager_sva, &pager_eva,
				(nswbuf*MAXPHYS) + pager_map_size, TRUE);
	exec_map = kmem_suballoc(kernel_map, &minaddr, &maxaddr,
				(16*ARG_MAX), TRUE);
	u_map = kmem_suballoc(kernel_map, &minaddr, &maxaddr,
				(maxproc*UPAGES*PAGE_SIZE), FALSE);

	/*
	 * Finally, allocate mbuf pool.  Since mclrefcnt is an off-size
	 * we use the more space efficient malloc in place of kmem_alloc.
	 */
	mclrefcnt = (char *)malloc(NMBCLUSTERS+CLBYTES/MCLBYTES,
				   M_MBUF, M_NOWAIT);
	bzero(mclrefcnt, NMBCLUSTERS+CLBYTES/MCLBYTES);
	mb_map = kmem_suballoc(kmem_map, (vm_offset_t *)&mbutl, &maxaddr,
			       VM_MBUF_SIZE, FALSE);
	/*
	 * Initialize callouts
	 */
	callfree = callout;
	for (i = 1; i < ncallout; i++)
		callout[i-1].c_next = &callout[i];

        if (boothowto & RB_CONFIG)
		userconfig();
	printf("avail memory = %d (%d pages)\n", ptoa(cnt.v_free_count), cnt.v_free_count);

#ifdef BOUNCE_BUFFERS
	/*
	 * init bounce buffers
	 */
	vm_bounce_init();
#endif

	/*
	 * Set up CPU-specific registers, cache, etc.
	 */
	initcpu();

	/*
	 * Set up buffers, so they can be used to read disk labels.
	 */
	bufinit();
	vm_pager_bufferinit();

	/*
	 * Configure the system.
	 */
	configure();
	if (bootverbose) {
		printf("BIOS Geometries:");
		for (i=0; i < N_BIOS_GEOM; i++)
			printf(" %x:%x\n", i, bootinfo.bi_bios_geom[i]);
		printf(" %d accounted for\n", bootinfo.bi_n_bios_used);
	}
}


struct cpu_nameclass i386_cpus[] = {
	{ "Intel 80286",	CPUCLASS_286 },		/* CPU_286   */
	{ "i386SX",		CPUCLASS_386 },		/* CPU_386SX */
	{ "i386DX",		CPUCLASS_386 },		/* CPU_386   */
	{ "i486SX",		CPUCLASS_486 },		/* CPU_486SX */
	{ "i486DX",		CPUCLASS_486 },		/* CPU_486   */
	{ "Pentium",		CPUCLASS_586 },		/* CPU_586   */
	{ "Cy486DLC",		CPUCLASS_486 },		/* CPU_486DLC */
};

static void
identifycpu()
{
	extern u_long cpu_id, cpu_high, cpu_feature;
	extern char cpu_vendor[];
	printf("CPU: ");
	if (cpu >= 0
	    && cpu < (sizeof i386_cpus/sizeof(struct cpu_nameclass))) {
		printf("%s", i386_cpus[cpu].cpu_name);
		cpu_class = i386_cpus[cpu].cpu_class;
		strncpy(cpu_model, i386_cpus[cpu].cpu_name, sizeof cpu_model);
	} else {
		printf("unknown cpu type %d\n", cpu);
		panic("startup: bad cpu id");
	}
	printf(" (");
	switch(cpu_class) {
	case CPUCLASS_286:
		printf("286");
		break;
	case CPUCLASS_386:
		printf("386");
		break;
	case CPUCLASS_486:
		printf("486");
		break;
	case CPUCLASS_586:
		printf("Pentium");
		break;
	default:
		printf("unknown");	/* will panic below... */
	}
	printf("-class CPU)");
#ifdef I586_CPU
	if(cpu_class == CPUCLASS_586) {
		calibrate_cyclecounter();
		printf(" %d MHz", pentium_mhz);
	}
#endif
	if(*cpu_vendor)
		printf("  Origin = \"%s\"",cpu_vendor);
	if(cpu_id)
		printf("  Id = 0x%lx",cpu_id);
	printf("\n");	/* cpu speed would be nice, but how? */
	if (!strcmp(cpu_vendor,"GenuineIntel")) {
		printf("  This is a");
		if ((cpu_id & 0xf00) > 3) {
			switch (cpu_id & 0x3000) {
			    case 0x1000: printf("Overdrive "); break;
			    case 0x2000: printf("Dual "); break;
			}
			if ((cpu_id & 0xf00) == 0x400)
			    printf("n i486");
			else if ((cpu_id & 0xf00) == 0x500)
			    printf(" Pentium ");
			else
			    printf(" unknown CPU");
			switch (cpu_id & 0xff0) {
			    case 0x400: printf("DX"); break;
			    case 0x410: printf("DX"); break;
			    case 0x420: printf("SX"); break;
			    case 0x430: printf("DX2"); break;
			    case 0x440: printf("SL"); break;
			    case 0x450: printf("SX2"); break;
			    case 0x470: printf("DX2 Write-Back Enhanced");
				break;
			    case 0x480: printf("DX4"); break;
			    case 0x510: printf("510\\60 or 567\\66"); break;
			    case 0x520: printf("735\\90 or 815\\100"); break;
			}
		}
		printf("  Stepping=%d", cpu_id & 0xf);
		if (cpu_high > 0) {
			printf("  Features=0x%lx",cpu_feature);
			if (cpu_feature & 0x1) printf(" FPU");
			if (cpu_feature & 0x2) printf(" VME");
			if (cpu_feature & 0x8) printf(" PSE");
			if (cpu_feature & 0x80) printf(" MCE");
			if (cpu_feature & 0x100) printf(" CX8");
			if (cpu_feature & 0x200) printf(" APIC");
		}
		printf("\n");
	}

	/*
	 * Now that we have told the user what they have,
	 * let them know if that machine type isn't configured.
	 */
	switch (cpu_class) {
	case CPUCLASS_286:	/* a 286 should not make it this far, anyway */
#if !defined(I386_CPU) && !defined(I486_CPU) && !defined(I586_CPU)
#error This kernel is not configured for one of the supported CPUs
#endif
#if !defined(I386_CPU)
	case CPUCLASS_386:
#endif
#if !defined(I486_CPU)
	case CPUCLASS_486:
#endif
#if !defined(I586_CPU)
	case CPUCLASS_586:
#endif
		panic("CPU class not configured");
	default:
		break;
	}
}

extern char kstack[];

/*
 * Send an interrupt to process.
 *
 * Stack is set up to allow sigcode stored
 * in u. to call routine, followed by kcall
 * to sigreturn routine below.  After sigreturn
 * resets the signal mask, the stack, and the
 * frame pointer, it returns to the user
 * specified pc, psl.
 */
void
sendsig(catcher, sig, mask, code)
	sig_t catcher;
	int sig, mask;
	unsigned code;
{
	register struct proc *p = curproc;
	register int *regs;
	register struct sigframe *fp;
	struct sigacts *psp = p->p_sigacts;
	int oonstack;

	regs = p->p_md.md_regs;
        oonstack = psp->ps_sigstk.ss_flags & SA_ONSTACK;
	/*
	 * Allocate and validate space for the signal handler
	 * context. Note that if the stack is in P0 space, the
	 * call to grow() is a nop, and the useracc() check
	 * will fail if the process has not already allocated
	 * the space with a `brk'.
	 */
        if ((psp->ps_flags & SAS_ALTSTACK) &&
	    (psp->ps_sigstk.ss_flags & SA_ONSTACK) == 0 &&
	    (psp->ps_sigonstack & sigmask(sig))) {
		fp = (struct sigframe *)(psp->ps_sigstk.ss_sp +
		    psp->ps_sigstk.ss_size - sizeof(struct sigframe));
		psp->ps_sigstk.ss_flags |= SA_ONSTACK;
	} else {
		fp = (struct sigframe *)(regs[tESP]
			- sizeof(struct sigframe));
	}

	/*
	 * grow() will return FALSE if the fp will not fit inside the stack
	 *	and the stack can not be grown. useracc will return FALSE
	 *	if access is denied.
	 */
	if ((grow(p, (int)fp) == FALSE) ||
	    (useracc((caddr_t)fp, sizeof (struct sigframe), B_WRITE) == FALSE)) {
		/*
		 * Process has trashed its stack; give it an illegal
		 * instruction to halt it in its tracks.
		 */
		SIGACTION(p, SIGILL) = SIG_DFL;
		sig = sigmask(SIGILL);
		p->p_sigignore &= ~sig;
		p->p_sigcatch &= ~sig;
		p->p_sigmask &= ~sig;
		psignal(p, SIGILL);
		return;
	}

	/*
	 * Build the argument list for the signal handler.
	 */
	if (p->p_sysent->sv_sigtbl) {
		if (sig < p->p_sysent->sv_sigsize)
			sig = p->p_sysent->sv_sigtbl[sig];
		else
			sig = p->p_sysent->sv_sigsize + 1;
	}
	fp->sf_signum = sig;
	fp->sf_code = code;
	fp->sf_scp = &fp->sf_sc;
	fp->sf_addr = (char *) regs[tERR];
	fp->sf_handler = catcher;

	/* save scratch registers */
	fp->sf_sc.sc_eax = regs[tEAX];
	fp->sf_sc.sc_ebx = regs[tEBX];
	fp->sf_sc.sc_ecx = regs[tECX];
	fp->sf_sc.sc_edx = regs[tEDX];
	fp->sf_sc.sc_esi = regs[tESI];
	fp->sf_sc.sc_edi = regs[tEDI];
	fp->sf_sc.sc_cs = regs[tCS];
	fp->sf_sc.sc_ds = regs[tDS];
	fp->sf_sc.sc_ss = regs[tSS];
	fp->sf_sc.sc_es = regs[tES];
	fp->sf_sc.sc_isp = regs[tISP];

	/*
	 * Build the signal context to be used by sigreturn.
	 */
	fp->sf_sc.sc_onstack = oonstack;
	fp->sf_sc.sc_mask = mask;
	fp->sf_sc.sc_sp = regs[tESP];
	fp->sf_sc.sc_fp = regs[tEBP];
	fp->sf_sc.sc_pc = regs[tEIP];
	fp->sf_sc.sc_ps = regs[tEFLAGS];
	regs[tESP] = (int)fp;
	regs[tEIP] = (int)((struct pcb *)kstack)->pcb_sigc;
	regs[tEFLAGS] &= ~PSL_VM;
	regs[tCS] = _ucodesel;
	regs[tDS] = _udatasel;
	regs[tES] = _udatasel;
	regs[tSS] = _udatasel;
}

/*
 * System call to cleanup state after a signal
 * has been taken.  Reset signal mask and
 * stack state from context left by sendsig (above).
 * Return to previous pc and psl as specified by
 * context left by sendsig. Check carefully to
 * make sure that the user has not modified the
 * state to gain improper privileges.
 */
struct sigreturn_args {
	struct sigcontext *sigcntxp;
};

int
sigreturn(p, uap, retval)
	struct proc *p;
	struct sigreturn_args *uap;
	int *retval;
{
	register struct sigcontext *scp;
	register struct sigframe *fp;
	register int *regs = p->p_md.md_regs;
	int eflags;

	/*
	 * (XXX old comment) regs[tESP] points to the return address.
	 * The user scp pointer is above that.
	 * The return address is faked in the signal trampoline code
	 * for consistency.
	 */
	scp = uap->sigcntxp;
	fp = (struct sigframe *)
	     ((caddr_t)scp - offsetof(struct sigframe, sf_sc));

	if (useracc((caddr_t)fp, sizeof (*fp), 0) == 0)
		return(EINVAL);

	/*
	 * Don't allow users to change privileged or reserved flags.
	 */
#define	EFLAGS_SECURE(ef, oef)	((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
	eflags = scp->sc_ps;
	/*
	 * XXX do allow users to change the privileged flag PSL_RF.  The
	 * cpu sets PSL_RF in tf_eflags for faults.  Debuggers should
	 * sometimes set it there too.  tf_eflags is kept in the signal
	 * context during signal handling and there is no other place
	 * to remember it, so the PSL_RF bit may be corrupted by the
	 * signal handler without us knowing.  Corruption of the PSL_RF
	 * bit at worst causes one more or one less debugger trap, so
	 * allowing it is fairly harmless.
	 */
	if (!EFLAGS_SECURE(eflags & ~PSL_RF, regs[tEFLAGS] & ~PSL_RF)) {
#ifdef DEBUG
    		printf("sigreturn: eflags = 0x%x\n", eflags);
#endif
    		return(EINVAL);
	}

	/*
	 * Don't allow users to load a valid privileged %cs.  Let the
	 * hardware check for invalid selectors, excess privilege in
	 * other selectors, invalid %eip's and invalid %esp's.
	 */
#define	CS_SECURE(cs)	(ISPL(cs) == SEL_UPL)
	if (!CS_SECURE(scp->sc_cs)) {
#ifdef DEBUG
    		printf("sigreturn: cs = 0x%x\n", scp->sc_cs);
#endif
		trapsignal(p, SIGBUS, T_PROTFLT);
		return(EINVAL);
	}

	/* restore scratch registers */
	regs[tEAX] = scp->sc_eax;
	regs[tEBX] = scp->sc_ebx;
	regs[tECX] = scp->sc_ecx;
	regs[tEDX] = scp->sc_edx;
	regs[tESI] = scp->sc_esi;
	regs[tEDI] = scp->sc_edi;
	regs[tCS] = scp->sc_cs;
	regs[tDS] = scp->sc_ds;
	regs[tES] = scp->sc_es;
	regs[tSS] = scp->sc_ss;
	regs[tISP] = scp->sc_isp;

	if (useracc((caddr_t)scp, sizeof (*scp), 0) == 0)
		return(EINVAL);

	if (scp->sc_onstack & 01)
		p->p_sigacts->ps_sigstk.ss_flags |= SA_ONSTACK;
	else
		p->p_sigacts->ps_sigstk.ss_flags &= ~SA_ONSTACK;
	p->p_sigmask = scp->sc_mask &~
	    (sigmask(SIGKILL)|sigmask(SIGCONT)|sigmask(SIGSTOP));
	regs[tEBP] = scp->sc_fp;
	regs[tESP] = scp->sc_sp;
	regs[tEIP] = scp->sc_pc;
	regs[tEFLAGS] = eflags;
	return(EJUSTRETURN);
}

/*
 * a simple function to make the system panic (and dump a vmcore)
 * in a predictable fashion
 */
void diediedie()
{
	panic("because you said to!");
}

int	waittime = -1;
struct pcb dumppcb;

__dead void
boot(arghowto)
	int arghowto;
{
	register long dummy;		/* r12 is reserved */
	register int howto;		/* r11 == how to boot */
	register int devtype;		/* r10 == major of root dev */
	extern int cold;

	if (cold) {
		printf("hit reset please");
		for(;;);
	}
	howto = arghowto;
	if ((howto&RB_NOSYNC) == 0 && waittime < 0) {
		register struct buf *bp;
		int iter, nbusy;

		waittime = 0;
		printf("\nsyncing disks... ");
		/*
		 * Release inodes held by texts before update.
		 */
		if (panicstr == 0)
			vnode_pager_umount(NULL);
		sync(curproc, NULL, NULL);

		for (iter = 0; iter < 20; iter++) {
			nbusy = 0;
			for (bp = &buf[nbuf]; --bp >= buf; ) {
				if ((bp->b_flags & (B_BUSY|B_INVAL)) == B_BUSY) {
					nbusy++;
				}
			}
			if (nbusy == 0)
				break;
			printf("%d ", nbusy);
			DELAY(40000 * iter);
		}
		if (nbusy) {
			/*
			 * Failed to sync all blocks. Indicate this and don't
			 * unmount filesystems (thus forcing an fsck on reboot).
			 */
			printf("giving up\n");
		} else {
			printf("done\n");
			/*
			 * Unmount filesystems
			 */
			if (panicstr == 0)
				vfs_unmountall();
		}
		DELAY(100000);			/* wait for console output to finish */
	}
	splhigh();
	devtype = major(rootdev);
	if (howto&RB_HALT) {
		printf("\n");
		printf("The operating system has halted.\n");
		printf("Please press any key to reboot.\n\n");
		cngetc();
	} else {
		if (howto & RB_DUMP) {
			savectx(&dumppcb, 0);
			dumppcb.pcb_ptd = rcr3();
			dumpsys();

			if (PANIC_REBOOT_WAIT_TIME != 0) {
				if (PANIC_REBOOT_WAIT_TIME != -1) {
					int loop;
					printf("Automatic reboot in %d seconds - press a key on the console to abort\n",
						PANIC_REBOOT_WAIT_TIME);
					for (loop = PANIC_REBOOT_WAIT_TIME; loop > 0; --loop) {
						DELAY(1000 * 1000); /* one second */
						if (cncheckc()) /* Did user type a key? */
							break;
					}
					if (!loop)
						goto die;
				}
			} else { /* zero time specified - reboot NOW */
				goto die;
			}
			printf("--> Press a key on the console to reboot <--\n");
			cngetc();
		}
	}
#ifdef lint
	dummy = 0; dummy = dummy;
	printf("howto %d, devtype %d\n", arghowto, devtype);
#endif
die:
	printf("Rebooting...\n");
	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
	cpu_reset();
	for(;;) ;
	/* NOTREACHED */
}

unsigned long	dumpmag = 0x8fca0101UL;	/* magic number for savecore */
int		dumpsize = 0;		/* also for savecore */

#ifdef DODUMP
int		dodump = 1;
#else
int		dodump = 0;
#endif
/*
 * Doadump comes here after turning off memory management and
 * getting on the dump stack, either when called above, or by
 * the auto-restart code.
 */
void
dumpsys()
{

	if (!dodump)
		return;
	if (dumpdev == NODEV)
		return;
	if ((minor(dumpdev)&07) != 1)
		return;
	dumpsize = Maxmem;
	printf("\ndumping to dev %lx, offset %ld\n", dumpdev, dumplo);
	printf("dump ");
	switch ((*bdevsw[major(dumpdev)].d_dump)(dumpdev)) {

	case ENXIO:
		printf("device bad\n");
		break;

	case EFAULT:
		printf("device not ready\n");
		break;

	case EINVAL:
		printf("area improper\n");
		break;

	case EIO:
		printf("i/o error\n");
		break;

	case EINTR:
		printf("aborted from console\n");
		break;

	default:
		printf("succeeded\n");
		break;
	}
}

static void
initcpu()
{
}

/*
 * Clear registers on exec
 */
void
setregs(p, entry, stack)
	struct proc *p;
	u_long entry;
	u_long stack;
{
	int *regs = p->p_md.md_regs;

	bzero(regs, sizeof(struct trapframe));
	regs[tEIP] = entry;
	regs[tESP] = stack;
	regs[tEFLAGS] = PSL_USER | (regs[tEFLAGS] & PSL_T);
	regs[tSS] = _udatasel;
	regs[tDS] = _udatasel;
	regs[tES] = _udatasel;
	regs[tCS] = _ucodesel;

	p->p_addr->u_pcb.pcb_flags = 0;	/* no fp at all */
	load_cr0(rcr0() | CR0_TS);	/* start emulating */
#if	NNPX > 0
	npxinit(__INITIAL_NPXCW__);
#endif	/* NNPX > 0 */
}

/*
 * machine dependent system variables.
 */
int
cpu_sysctl(name, namelen, oldp, oldlenp, newp, newlen, p)
	int *name;
	u_int namelen;
	void *oldp;
	size_t *oldlenp;
	void *newp;
	size_t newlen;
	struct proc *p;
{
	int error;

	/* all sysctl names at this level are terminal */
	if (namelen != 1)
		return (ENOTDIR);               /* overloaded */

	switch (name[0]) {
	case CPU_CONSDEV:
		return (sysctl_rdstruct(oldp, oldlenp, newp, &cn_tty->t_dev,
		   sizeof cn_tty->t_dev));
	case CPU_ADJKERNTZ:
		error = sysctl_int(oldp, oldlenp, newp, newlen, &adjkerntz);
		if (!error && newp)
			resettodr();
		return error;
	case CPU_DISRTCSET:
		return (sysctl_int(oldp, oldlenp, newp,	newlen,	&disable_rtc_set));
	default:
		return (EOPNOTSUPP);
	}
	/* NOTREACHED */
}

/*
 * Initialize 386 and configure to run kernel
 */

/*
 * Initialize segments & interrupt table
 */

int currentldt;
int _default_ldt;
union descriptor gdt[NGDT];		/* global descriptor table */
struct gate_descriptor idt[NIDT];	/* interrupt descriptor table */
union descriptor ldt[NLDT];		/* local descriptor table */

struct	i386tss	tss, panic_tss;

extern  struct user *proc0paddr;

/* software prototypes -- in more palatable form */
struct soft_segment_descriptor gdt_segs[] = {
/* GNULL_SEL	0 Null Descriptor */
{	0x0,			/* segment base address  */
	0x0,			/* length */
	0,			/* segment type */
	0,			/* segment descriptor priority level */
	0,			/* segment descriptor present */
	0, 0,
	0,			/* default 32 vs 16 bit size */
	0  			/* limit granularity (byte/page units)*/ },
/* GCODE_SEL	1 Code Descriptor for kernel */
{	0x0,			/* segment base address  */
	0xfffff,		/* length - all address space */
	SDT_MEMERA,		/* segment type */
	0,			/* segment descriptor priority level */
	1,			/* segment descriptor present */
	0, 0,
	1,			/* default 32 vs 16 bit size */
	1  			/* limit granularity (byte/page units)*/ },
/* GDATA_SEL	2 Data Descriptor for kernel */
{	0x0,			/* segment base address  */
	0xfffff,		/* length - all address space */
	SDT_MEMRWA,		/* segment type */
	0,			/* segment descriptor priority level */
	1,			/* segment descriptor present */
	0, 0,
	1,			/* default 32 vs 16 bit size */
	1  			/* limit granularity (byte/page units)*/ },
/* GLDT_SEL	3 LDT Descriptor */
{	(int) ldt,		/* segment base address  */
	sizeof(ldt)-1,		/* length - all address space */
	SDT_SYSLDT,		/* segment type */
	0,			/* segment descriptor priority level */
	1,			/* segment descriptor present */
	0, 0,
	0,			/* unused - default 32 vs 16 bit size */
	0  			/* limit granularity (byte/page units)*/ },
/* GTGATE_SEL	4 Null Descriptor - Placeholder */
{	0x0,			/* segment base address  */
	0x0,			/* length - all address space */
	0,			/* segment type */
	0,			/* segment descriptor priority level */
	0,			/* segment descriptor present */
	0, 0,
	0,			/* default 32 vs 16 bit size */
	0  			/* limit granularity (byte/page units)*/ },
/* GPANIC_SEL	5 Panic Tss Descriptor */
{	(int) &panic_tss,	/* segment base address  */
	sizeof(tss)-1,		/* length - all address space */
	SDT_SYS386TSS,		/* segment type */
	0,			/* segment descriptor priority level */
	1,			/* segment descriptor present */
	0, 0,
	0,			/* unused - default 32 vs 16 bit size */
	0  			/* limit granularity (byte/page units)*/ },
/* GPROC0_SEL	6 Proc 0 Tss Descriptor */
{	(int) kstack,		/* segment base address  */
	sizeof(tss)-1,		/* length - all address space */
	SDT_SYS386TSS,		/* segment type */
	0,			/* segment descriptor priority level */
	1,			/* segment descriptor present */
	0, 0,
	0,			/* unused - default 32 vs 16 bit size */
	0  			/* limit granularity (byte/page units)*/ },
/* GUSERLDT_SEL	7 User LDT Descriptor per process */
{	(int) ldt,		/* segment base address  */
	(512 * sizeof(union descriptor)-1),		/* length */
	SDT_SYSLDT,		/* segment type */
	0,			/* segment descriptor priority level */
	1,			/* segment descriptor present */
	0, 0,
	0,			/* unused - default 32 vs 16 bit size */
	0  			/* limit granularity (byte/page units)*/ },
/* GAPMCODE32_SEL 8 APM BIOS 32-bit interface (32bit Code) */
{	0,			/* segment base address (overwritten by APM)  */
	0xfffff,		/* length */
	SDT_MEMERA,		/* segment type */
	0,			/* segment descriptor priority level */
	1,			/* segment descriptor present */
	0, 0,
	1,			/* default 32 vs 16 bit size */
	1  			/* limit granularity (byte/page units)*/ },
/* GAPMCODE16_SEL 9 APM BIOS 32-bit interface (16bit Code) */
{	0,			/* segment base address (overwritten by APM)  */
	0xfffff,		/* length */
	SDT_MEMERA,		/* segment type */
	0,			/* segment descriptor priority level */
	1,			/* segment descriptor present */
	0, 0,
	0,			/* default 32 vs 16 bit size */
	1  			/* limit granularity (byte/page units)*/ },
/* GAPMDATA_SEL	10 APM BIOS 32-bit interface (Data) */
{	0,			/* segment base address (overwritten by APM) */
	0xfffff,		/* length */
	SDT_MEMRWA,		/* segment type */
	0,			/* segment descriptor priority level */
	1,			/* segment descriptor present */
	0, 0,
	1,			/* default 32 vs 16 bit size */
	1  			/* limit granularity (byte/page units)*/ },
};

struct soft_segment_descriptor ldt_segs[] = {
	/* Null Descriptor - overwritten by call gate */
{	0x0,			/* segment base address  */
	0x0,			/* length - all address space */
	0,			/* segment type */
	0,			/* segment descriptor priority level */
	0,			/* segment descriptor present */
	0, 0,
	0,			/* default 32 vs 16 bit size */
	0  			/* limit granularity (byte/page units)*/ },
	/* Null Descriptor - overwritten by call gate */
{	0x0,			/* segment base address  */
	0x0,			/* length - all address space */
	0,			/* segment type */
	0,			/* segment descriptor priority level */
	0,			/* segment descriptor present */
	0, 0,
	0,			/* default 32 vs 16 bit size */
	0  			/* limit granularity (byte/page units)*/ },
	/* Null Descriptor - overwritten by call gate */
{	0x0,			/* segment base address  */
	0x0,			/* length - all address space */
	0,			/* segment type */
	0,			/* segment descriptor priority level */
	0,			/* segment descriptor present */
	0, 0,
	0,			/* default 32 vs 16 bit size */
	0  			/* limit granularity (byte/page units)*/ },
	/* Code Descriptor for user */
{	0x0,			/* segment base address  */
	0xfffff,		/* length - all address space */
	SDT_MEMERA,		/* segment type */
	SEL_UPL,		/* segment descriptor priority level */
	1,			/* segment descriptor present */
	0, 0,
	1,			/* default 32 vs 16 bit size */
	1  			/* limit granularity (byte/page units)*/ },
	/* Data Descriptor for user */
{	0x0,			/* segment base address  */
	0xfffff,		/* length - all address space */
	SDT_MEMRWA,		/* segment type */
	SEL_UPL,		/* segment descriptor priority level */
	1,			/* segment descriptor present */
	0, 0,
	1,			/* default 32 vs 16 bit size */
	1  			/* limit granularity (byte/page units)*/ },
};

void
setidt(idx, func, typ, dpl)
	int idx;
	inthand_t *func;
	int typ;
	int dpl;
{
	struct gate_descriptor *ip = idt + idx;

	ip->gd_looffset = (int)func;
	ip->gd_selector = 8;
	ip->gd_stkcpy = 0;
	ip->gd_xx = 0;
	ip->gd_type = typ;
	ip->gd_dpl = dpl;
	ip->gd_p = 1;
	ip->gd_hioffset = ((int)func)>>16 ;
}

#define	IDTVEC(name)	__CONCAT(X,name)

extern inthand_t
	IDTVEC(div), IDTVEC(dbg), IDTVEC(nmi), IDTVEC(bpt), IDTVEC(ofl),
	IDTVEC(bnd), IDTVEC(ill), IDTVEC(dna), IDTVEC(dble), IDTVEC(fpusegm),
	IDTVEC(tss), IDTVEC(missing), IDTVEC(stk), IDTVEC(prot),
	IDTVEC(page), IDTVEC(rsvd), IDTVEC(fpu), IDTVEC(align),
	IDTVEC(syscall);

void
sdtossd(sd, ssd)
	struct segment_descriptor *sd;
	struct soft_segment_descriptor *ssd;
{
	ssd->ssd_base  = (sd->sd_hibase << 24) | sd->sd_lobase;
	ssd->ssd_limit = (sd->sd_hilimit << 16) | sd->sd_lolimit;
	ssd->ssd_type  = sd->sd_type;
	ssd->ssd_dpl   = sd->sd_dpl;
	ssd->ssd_p     = sd->sd_p;
	ssd->ssd_def32 = sd->sd_def32;
	ssd->ssd_gran  = sd->sd_gran;
}

void
init386(first)
	int first;
{
	extern char etext[];
	int x;
	unsigned biosbasemem, biosextmem;
	struct gate_descriptor *gdp;
	int gsel_tss;
	extern int sigcode,szsigcode;
	/* table descriptors - used to load tables by microp */
	struct region_descriptor r_gdt, r_idt;
	int	pagesinbase, pagesinext;
	int	target_page;
	extern struct pte *CMAP1;
	extern caddr_t CADDR1;

	proc0.p_addr = proc0paddr;

	/*
	 * Initialize the console before we print anything out.
	 */

	cninit ();

	/*
	 * make gdt memory segments, the code segment goes up to end of the
	 * page with etext in it, the data segment goes to the end of
	 * the address space
	 */
	/*
	 * XXX text protection is temporarily (?) disabled.  The limit was
	 * i386_btop(i386_round_page(etext)) - 1.
	 */
	gdt_segs[GCODE_SEL].ssd_limit = i386_btop(0) - 1;
	gdt_segs[GDATA_SEL].ssd_limit = i386_btop(0) - 1;
	for (x = 0; x < NGDT; x++)
		ssdtosd(&gdt_segs[x], &gdt[x].sd);

	/* make ldt memory segments */
	/*
	 * The data segment limit must not cover the user area because we
	 * don't want the user area to be writable in copyout() etc. (page
	 * level protection is lost in kernel mode on 386's).  Also, we
	 * don't want the user area to be writable directly (page level
	 * protection of the user area is not available on 486's with
	 * CR0_WP set, because there is no user-read/kernel-write mode).
	 *
	 * XXX - VM_MAXUSER_ADDRESS is an end address, not a max.  And it
	 * should be spelled ...MAX_USER...
	 */
#define VM_END_USER_RW_ADDRESS	VM_MAXUSER_ADDRESS
	/*
	 * The code segment limit has to cover the user area until we move
	 * the signal trampoline out of the user area.  This is safe because
	 * the code segment cannot be written to directly.
	 */
#define VM_END_USER_R_ADDRESS	(VM_END_USER_RW_ADDRESS + UPAGES * NBPG)
	ldt_segs[LUCODE_SEL].ssd_limit = i386_btop(VM_END_USER_R_ADDRESS) - 1;
	ldt_segs[LUDATA_SEL].ssd_limit = i386_btop(VM_END_USER_RW_ADDRESS) - 1;
	/* Note. eventually want private ldts per process */
	for (x = 0; x < NLDT; x++)
		ssdtosd(&ldt_segs[x], &ldt[x].sd);

	/* exceptions */
	for (x = 0; x < NIDT; x++)
		setidt(x, &IDTVEC(rsvd), SDT_SYS386TGT, SEL_KPL);
	setidt(0, &IDTVEC(div),  SDT_SYS386TGT, SEL_KPL);
	setidt(1, &IDTVEC(dbg),  SDT_SYS386TGT, SEL_KPL);
	setidt(2, &IDTVEC(nmi),  SDT_SYS386TGT, SEL_KPL);
 	setidt(3, &IDTVEC(bpt),  SDT_SYS386TGT, SEL_UPL);
	setidt(4, &IDTVEC(ofl),  SDT_SYS386TGT, SEL_UPL);
	setidt(5, &IDTVEC(bnd),  SDT_SYS386TGT, SEL_KPL);
	setidt(6, &IDTVEC(ill),  SDT_SYS386TGT, SEL_KPL);
	setidt(7, &IDTVEC(dna),  SDT_SYS386TGT, SEL_KPL);
	setidt(8, &IDTVEC(dble),  SDT_SYS386TGT, SEL_KPL);
	setidt(9, &IDTVEC(fpusegm),  SDT_SYS386TGT, SEL_KPL);
	setidt(10, &IDTVEC(tss),  SDT_SYS386TGT, SEL_KPL);
	setidt(11, &IDTVEC(missing),  SDT_SYS386TGT, SEL_KPL);
	setidt(12, &IDTVEC(stk),  SDT_SYS386TGT, SEL_KPL);
	setidt(13, &IDTVEC(prot),  SDT_SYS386TGT, SEL_KPL);
	setidt(14, &IDTVEC(page),  SDT_SYS386TGT, SEL_KPL);
	setidt(15, &IDTVEC(rsvd),  SDT_SYS386TGT, SEL_KPL);
	setidt(16, &IDTVEC(fpu),  SDT_SYS386TGT, SEL_KPL);
	setidt(17, &IDTVEC(align), SDT_SYS386TGT, SEL_KPL);

#include	"isa.h"
#if	NISA >0
	isa_defaultirq();
#endif

	r_gdt.rd_limit = sizeof(gdt) - 1;
	r_gdt.rd_base =  (int) gdt;
	lgdt(&r_gdt);

	r_idt.rd_limit = sizeof(idt) - 1;
	r_idt.rd_base = (int) idt;
	lidt(&r_idt);

	_default_ldt = GSEL(GLDT_SEL, SEL_KPL);
	lldt(_default_ldt);
	currentldt = _default_ldt;

#ifdef DDB
	kdb_init();
	if (boothowto & RB_KDB)
		Debugger("Boot flags requested debugger");
#endif

	/* Use BIOS values stored in RTC CMOS RAM, since probing
	 * breaks certain 386 AT relics.
	 */
	biosbasemem = rtcin(RTC_BASELO)+ (rtcin(RTC_BASEHI)<<8);
	biosextmem = rtcin(RTC_EXTLO)+ (rtcin(RTC_EXTHI)<<8);

	/*
	 * Print a warning if the official BIOS interface disagrees
	 * with the hackish interface used above.  Eventually only
	 * the official interface should be used.
	 */
	if (bootinfo.bi_memsizes_valid) {
		if (bootinfo.bi_basemem != biosbasemem)
			printf("BIOS basemem (%dK) != RTC basemem (%dK)\n",
			       bootinfo.bi_basemem, biosbasemem);
		if (bootinfo.bi_extmem != biosextmem)
			printf("BIOS extmem (%dK) != RTC extmem (%dK)\n",
			       bootinfo.bi_extmem, biosextmem);
	}

	/*
	 * If BIOS tells us that it has more than 640k in the basemem,
	 *	don't believe it - set it to 640k.
	 */
	if (biosbasemem > 640)
		biosbasemem = 640;

	/*
	 * Some 386 machines might give us a bogus number for extended
	 *	mem. If this happens, stop now.
	 */
#ifndef LARGEMEM
	if (biosextmem > 65536) {
		panic("extended memory beyond limit of 64MB");
		/* NOTREACHED */
	}
#endif

	pagesinbase = biosbasemem * 1024 / NBPG;
	pagesinext = biosextmem * 1024 / NBPG;

	/*
	 * Special hack for chipsets that still remap the 384k hole when
	 *	there's 16MB of memory - this really confuses people that
	 *	are trying to use bus mastering ISA controllers with the
	 *	"16MB limit"; they only have 16MB, but the remapping puts
	 *	them beyond the limit.
	 */
	/*
	 * If extended memory is between 15-16MB (16-17MB phys address range),
	 *	chop it to 15MB.
	 */
	if ((pagesinext > 3840) && (pagesinext < 4096))
		pagesinext = 3840;

	/*
	 * Maxmem isn't the "maximum memory", it's one larger than the
	 * highest page of of the physical address space. It should be
	 * called something like "Maxphyspage".
	 */
	Maxmem = pagesinext + 0x100000/PAGE_SIZE;

#ifdef MAXMEM
	Maxmem = MAXMEM/4;
#endif
	/*
	 * Calculate number of physical pages, but account for Maxmem
	 *	adjustment above.
	 */
	physmem = pagesinbase + Maxmem - 0x100000/PAGE_SIZE;

	/* call pmap initialization to make new kernel address space */
	pmap_bootstrap (first, 0);

	/*
	 * Do a quick, non-destructive check over extended memory to verify
	 * what the BIOS tells us agrees with reality. Adjust down Maxmem
	 * if we find that the page can't be correctly written to/read from.
	 */

	for (target_page = Maxmem - 1; target_page >= atop(first); target_page--) {
		int tmp;

		/*
		 * map page into kernel: valid, read/write, non-cacheable
		 */
		*(int *)CMAP1 = PG_V | PG_KW | PG_N | ptoa(target_page);
		pmap_update();

		tmp = *(int *)CADDR1;
		/*
		 * Test for alternating 1's and 0's
		 */
		*(int *)CADDR1 = 0xaaaaaaaa;
		if (*(int *)CADDR1 != 0xaaaaaaaa) {
			Maxmem = target_page;
			badpages++;
			continue;
		}
		/*
		 * Test for alternating 0's and 1's
		 */
		*(int *)CADDR1 = 0x55555555;
		if (*(int *)CADDR1 != 0x55555555) {
			Maxmem = target_page;
			badpages++;
			continue;
		}
		/*
		 * Test for all 1's
		 */
		*(int *)CADDR1 = 0xffffffff;
		if (*(int *)CADDR1 != 0xffffffff) {
			Maxmem = target_page;
			badpages++;
			continue;
		}
		/*
		 * Test for all 0's
		 */
		*(int *)CADDR1 = 0x0;
		if (*(int *)CADDR1 != 0x0) {
			/*
			 * test of page failed
			 */
			Maxmem = target_page;
			badpages++;
			continue;
		}
		*(int *)CADDR1 = tmp;
	}
	if (badpages != 0)
		printf("WARNING: BIOS extended memory size and reality don't agree.\n");

	*(int *)CMAP1 = 0;
	pmap_update();

	avail_end = (Maxmem << PAGE_SHIFT)
		    - i386_round_page(sizeof(struct msgbuf));

	/*
	 * Initialize pointers to the two chunks of memory; for use
	 *	later in vm_page_startup.
	 */
	/* avail_start is initialized in pmap_bootstrap */
	x = 0;
	if (pagesinbase > 1) {
		phys_avail[x++] = NBPG;		/* skip first page of memory */
		phys_avail[x++] = pagesinbase * NBPG;	/* memory up to the ISA hole */
	}
	phys_avail[x++] = avail_start;	/* memory up to the end */
	phys_avail[x++] = avail_end;
	phys_avail[x++] = 0;		/* no more chunks */
	phys_avail[x++] = 0;

	/* now running on new page tables, configured,and u/iom is accessible */

	/* make a initial tss so microp can get interrupt stack on syscall! */
	proc0.p_addr->u_pcb.pcb_tss.tss_esp0 = (int) kstack + UPAGES*NBPG;
	proc0.p_addr->u_pcb.pcb_tss.tss_ss0 = GSEL(GDATA_SEL, SEL_KPL) ;
	gsel_tss = GSEL(GPROC0_SEL, SEL_KPL);

	((struct i386tss *)gdt_segs[GPROC0_SEL].ssd_base)->tss_ioopt =
		(sizeof(tss))<<16;

	ltr(gsel_tss);

	/* make a call gate to reenter kernel with */
	gdp = &ldt[LSYS5CALLS_SEL].gd;

	x = (int) &IDTVEC(syscall);
	gdp->gd_looffset = x++;
	gdp->gd_selector = GSEL(GCODE_SEL,SEL_KPL);
	gdp->gd_stkcpy = 1;
	gdp->gd_type = SDT_SYS386CGT;
	gdp->gd_dpl = SEL_UPL;
	gdp->gd_p = 1;
	gdp->gd_hioffset = ((int) &IDTVEC(syscall)) >>16;

	/* transfer to user mode */

	_ucodesel = LSEL(LUCODE_SEL, SEL_UPL);
	_udatasel = LSEL(LUDATA_SEL, SEL_UPL);

	/* setup proc 0's pcb */
	bcopy(&sigcode, proc0.p_addr->u_pcb.pcb_sigc, szsigcode);
	proc0.p_addr->u_pcb.pcb_flags = 0;
	proc0.p_addr->u_pcb.pcb_ptd = IdlePTD;
}

/*
 * The registers are in the frame; the frame is in the user area of
 * the process in question; when the process is active, the registers
 * are in "the kernel stack"; when it's not, they're still there, but
 * things get flipped around.  So, since p->p_md.md_regs is the whole address
 * of the register set, take its offset from the kernel stack, and
 * index into the user block.  Don't you just *love* virtual memory?
 * (I'm starting to think seymour is right...)
 */
#define	TF_REGP(p)	((struct trapframe *) \
			 ((char *)(p)->p_addr \
			  + ((char *)(p)->p_md.md_regs - kstack)))

int
ptrace_set_pc(p, addr)
	struct proc *p;
	unsigned int addr;
{
	TF_REGP(p)->tf_eip = addr;
	return (0);
}

int
ptrace_single_step(p)
	struct proc *p;
{
	TF_REGP(p)->tf_eflags |= PSL_T;
	return (0);
}

int
ptrace_getregs(p, addr)
	struct proc *p;
	unsigned int *addr;
{
	int error;
	struct reg regs;

	error = fill_regs(p, &regs);
	if (error)
		return (error);
	return (copyout(&regs, addr, sizeof regs));
}

int
ptrace_setregs(p, addr)
	struct proc *p;
	unsigned int *addr;
{
	int error;
	struct reg regs;

	error = copyin(addr, &regs, sizeof regs);
	if (error)
		return (error);
	return (set_regs(p, &regs));
}

int ptrace_write_u(p, off, data)
	struct proc *p;
	vm_offset_t off;
	int data;
{
	struct trapframe frame_copy;
	vm_offset_t min;
	struct trapframe *tp;

	/*
	 * Privileged kernel state is scattered all over the user area.
	 * Only allow write access to parts of regs and to fpregs.
	 */
	min = (char *)p->p_md.md_regs - kstack;
	if (off >= min && off <= min + sizeof(struct trapframe) - sizeof(int)) {
		tp = TF_REGP(p);
		frame_copy = *tp;
		*(int *)((char *)&frame_copy + (off - min)) = data;
		if (!EFLAGS_SECURE(frame_copy.tf_eflags, tp->tf_eflags) ||
		    !CS_SECURE(frame_copy.tf_cs))
			return (EINVAL);
		*(int*)((char *)p->p_addr + off) = data;
		return (0);
	}
	min = offsetof(struct user, u_pcb) + offsetof(struct pcb, pcb_savefpu);
	if (off >= min && off <= min + sizeof(struct save87) - sizeof(int)) {
		*(int*)((char *)p->p_addr + off) = data;
		return (0);
	}
	return (EFAULT);
}

int
fill_regs(p, regs)
	struct proc *p;
	struct reg *regs;
{
	struct trapframe *tp;

	tp = TF_REGP(p);
	regs->r_es = tp->tf_es;
	regs->r_ds = tp->tf_ds;
	regs->r_edi = tp->tf_edi;
	regs->r_esi = tp->tf_esi;
	regs->r_ebp = tp->tf_ebp;
	regs->r_ebx = tp->tf_ebx;
	regs->r_edx = tp->tf_edx;
	regs->r_ecx = tp->tf_ecx;
	regs->r_eax = tp->tf_eax;
	regs->r_eip = tp->tf_eip;
	regs->r_cs = tp->tf_cs;
	regs->r_eflags = tp->tf_eflags;
	regs->r_esp = tp->tf_esp;
	regs->r_ss = tp->tf_ss;
	return (0);
}

int
set_regs(p, regs)
	struct proc *p;
	struct reg *regs;
{
	struct trapframe *tp;

	tp = TF_REGP(p);
	if (!EFLAGS_SECURE(regs->r_eflags, tp->tf_eflags) ||
	    !CS_SECURE(regs->r_cs))
		return (EINVAL);
	tp->tf_es = regs->r_es;
	tp->tf_ds = regs->r_ds;
	tp->tf_edi = regs->r_edi;
	tp->tf_esi = regs->r_esi;
	tp->tf_ebp = regs->r_ebp;
	tp->tf_ebx = regs->r_ebx;
	tp->tf_edx = regs->r_edx;
	tp->tf_ecx = regs->r_ecx;
	tp->tf_eax = regs->r_eax;
	tp->tf_eip = regs->r_eip;
	tp->tf_cs = regs->r_cs;
	tp->tf_eflags = regs->r_eflags;
	tp->tf_esp = regs->r_esp;
	tp->tf_ss = regs->r_ss;
	return (0);
}

#ifndef DDB
void
Debugger(const char *msg)
{
	printf("Debugger(\"%s\") called.\n", msg);
}
#endif /* no DDB */

#include <sys/disklabel.h>
#define b_cylin	b_resid
/*
 * Determine the size of the transfer, and make sure it is
 * within the boundaries of the partition. Adjust transfer
 * if needed, and signal errors or early completion.
 */
int
bounds_check_with_label(struct buf *bp, struct disklabel *lp, int wlabel)
{
        struct partition *p = lp->d_partitions + dkpart(bp->b_dev);
        int labelsect = lp->d_partitions[0].p_offset;
        int maxsz = p->p_size,
                sz = (bp->b_bcount + DEV_BSIZE - 1) >> DEV_BSHIFT;

        /* overwriting disk label ? */
        /* XXX should also protect bootstrap in first 8K */
        if (bp->b_blkno + p->p_offset <= LABELSECTOR + labelsect &&
#if LABELSECTOR != 0
            bp->b_blkno + p->p_offset + sz > LABELSECTOR + labelsect &&
#endif
            (bp->b_flags & B_READ) == 0 && wlabel == 0) {
                bp->b_error = EROFS;
                goto bad;
        }

#if     defined(DOSBBSECTOR) && defined(notyet)
        /* overwriting master boot record? */
        if (bp->b_blkno + p->p_offset <= DOSBBSECTOR &&
            (bp->b_flags & B_READ) == 0 && wlabel == 0) {
                bp->b_error = EROFS;
                goto bad;
        }
#endif

        /* beyond partition? */
        if (bp->b_blkno < 0 || bp->b_blkno + sz > maxsz) {
                /* if exactly at end of disk, return an EOF */
                if (bp->b_blkno == maxsz) {
                        bp->b_resid = bp->b_bcount;
                        return(0);
                }
                /* or truncate if part of it fits */
                sz = maxsz - bp->b_blkno;
                if (sz <= 0) {
                        bp->b_error = EINVAL;
                        goto bad;
                }
                bp->b_bcount = sz << DEV_BSHIFT;
        }

        /* calculate cylinder for disksort to order transfers with */
        bp->b_pblkno = bp->b_blkno + p->p_offset;
        bp->b_cylin = bp->b_pblkno / lp->d_secpercyl;
        return(1);

bad:
        bp->b_flags |= B_ERROR;
        return(-1);
}

int
disk_externalize(int drive, void *userp, size_t *maxlen)
{
	if(*maxlen < sizeof drive) {
		return ENOMEM;
	}

	*maxlen -= sizeof drive;
	return copyout(&drive, userp, sizeof drive);
}