Change method to determine base memory size.

[FreeBSD/FreeBSD.git] / 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
 * $FreeBSD$
 */

#include "opt_atalk.h"
#include "opt_compat.h"
#include "opt_cpu.h"
#include "opt_ddb.h"
#include "opt_inet.h"
#include "opt_ipx.h"
#include "opt_isa.h"
#include "opt_maxmem.h"
#include "opt_msgbuf.h"
#include "opt_npx.h"
#include "opt_perfmon.h"
#include "opt_kstack_pages.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/signalvar.h>
#include <sys/imgact.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/pcpu.h>
#include <sys/proc.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/reboot.h>
#include <sys/callout.h>
#include <sys/msgbuf.h>
#include <sys/sched.h>
#include <sys/sysent.h>
#include <sys/sysctl.h>
#include <sys/ucontext.h>
#include <sys/vmmeter.h>
#include <sys/bus.h>
#include <sys/eventhandler.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_kern.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_pager.h>
#include <vm/vm_extern.h>

#include <sys/user.h>
#include <sys/exec.h>
#include <sys/cons.h>

#include <ddb/ddb.h>

#include <net/netisr.h>

#include <machine/cpu.h>
#include <machine/cputypes.h>
#include <machine/reg.h>
#include <machine/clock.h>
#include <machine/specialreg.h>
#include <machine/bootinfo.h>
#include <machine/md_var.h>
#include <machine/pc/bios.h>
#include <machine/pcb_ext.h>            /* pcb.h included via sys/user.h */
#include <machine/proc.h>
#ifdef PERFMON
#include <machine/perfmon.h>
#endif
#ifdef SMP
#include <machine/privatespace.h>
#include <machine/smp.h>
#endif

#include <i386/isa/icu.h>
#include <i386/isa/intr_machdep.h>
#include <isa/rtc.h>
#include <machine/vm86.h>
#include <sys/ptrace.h>
#include <machine/sigframe.h>

extern void init386(int first);
extern void dblfault_handler(void);

extern void printcpuinfo(void); /* XXX header file */
extern void earlysetcpuclass(void);     /* same header file */
extern void finishidentcpu(void);
extern void panicifcpuunsupported(void);
extern void initializecpu(void);

#define CS_SECURE(cs)           (ISPL(cs) == SEL_UPL)
#define EFL_SECURE(ef, oef)     ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)

#if !defined(CPU_ENABLE_SSE) && defined(I686_CPU)
#define CPU_ENABLE_SSE
#endif
#if defined(CPU_DISABLE_SSE)
#undef CPU_ENABLE_SSE
#endif

static void cpu_startup(void *);
static void fpstate_drop(struct thread *td);
static void get_fpcontext(struct thread *td, mcontext_t *mcp);
static int  set_fpcontext(struct thread *td, const mcontext_t *mcp);
#ifdef CPU_ENABLE_SSE
static void set_fpregs_xmm(struct save87 *, struct savexmm *);
static void fill_fpregs_xmm(struct savexmm *, struct save87 *);
#endif /* CPU_ENABLE_SSE */
SYSINIT(cpu, SI_SUB_CPU, SI_ORDER_FIRST, cpu_startup, NULL)

int     _udatasel, _ucodesel;
u_int   atdevbase;

#if defined(SWTCH_OPTIM_STATS)
extern int swtch_optim_stats;
SYSCTL_INT(_debug, OID_AUTO, swtch_optim_stats,
        CTLFLAG_RD, &swtch_optim_stats, 0, "");
SYSCTL_INT(_debug, OID_AUTO, tlb_flush_count,
        CTLFLAG_RD, &tlb_flush_count, 0, "");
#endif

long physmem = 0;
int cold = 1;

#ifdef COMPAT_43
static void osendsig(sig_t catcher, int sig, sigset_t *mask, u_long code);
#endif

static int
sysctl_hw_physmem(SYSCTL_HANDLER_ARGS)
{
        u_long val;

        val = ctob(physmem);
        return (sysctl_handle_long(oidp, &val, 0, req));
}

SYSCTL_PROC(_hw, HW_PHYSMEM, physmem, CTLTYPE_ULONG | CTLFLAG_RD,
        0, 0, sysctl_hw_physmem, "LU", "");

static int
sysctl_hw_usermem(SYSCTL_HANDLER_ARGS)
{
        u_long val;

        val = ctob(physmem - cnt.v_wire_count);
        return (sysctl_handle_long(oidp, &val, 0, req));
}

SYSCTL_PROC(_hw, HW_USERMEM, usermem, CTLTYPE_ULONG | CTLFLAG_RD,
        0, 0, sysctl_hw_usermem, "LU", "");

static int
sysctl_hw_availpages(SYSCTL_HANDLER_ARGS)
{
        u_long val;

        val = i386_btop(avail_end - avail_start);
        return (sysctl_handle_long(oidp, &val, 0, req));
}

SYSCTL_PROC(_hw, OID_AUTO, availpages, CTLTYPE_ULONG | CTLFLAG_RD,
        0, 0, sysctl_hw_availpages, "LU", "");

long Maxmem = 0;

vm_offset_t phys_avail[10];

/* must be 2 less so 0 0 can signal end of chunks */
#define PHYS_AVAIL_ARRAY_END ((sizeof(phys_avail) / sizeof(vm_offset_t)) - 2)

struct kva_md_info kmi;

static struct trapframe proc0_tf;
#ifndef SMP
static struct pcpu __pcpu;
#endif

struct mtx icu_lock;

static void
cpu_startup(dummy)
        void *dummy;
{
        /*
         * Good {morning,afternoon,evening,night}.
         */
        earlysetcpuclass();
        startrtclock();
        printcpuinfo();
        panicifcpuunsupported();
#ifdef PERFMON
        perfmon_init();
#endif
        printf("real memory  = %u (%uK bytes)\n", ptoa(Maxmem),
            ptoa(Maxmem) / 1024);
        /*
         * Display any holes after the first chunk of extended memory.
         */
        if (bootverbose) {
                int indx;

                printf("Physical memory chunk(s):\n");
                for (indx = 0; phys_avail[indx + 1] != 0; indx += 2) {
                        unsigned int size1;

                        size1 = phys_avail[indx + 1] - phys_avail[indx];
                        printf("0x%08x - 0x%08x, %u bytes (%u pages)\n",
                            phys_avail[indx], phys_avail[indx + 1] - 1, size1,
                            size1 / PAGE_SIZE);
                }
        }

        vm_ksubmap_init(&kmi);

        printf("avail memory = %u (%uK bytes)\n", ptoa(cnt.v_free_count),
            ptoa(cnt.v_free_count) / 1024);

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

#ifndef SMP
        /* For SMP, we delay the cpu_setregs() until after SMP startup. */
        cpu_setregs();
#endif
}

/*
 * Send an interrupt to process.
 *
 * Stack is set up to allow sigcode stored
 * at top 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.
 */
#ifdef COMPAT_43
static void
osendsig(catcher, sig, mask, code)
        sig_t catcher;
        int sig;
        sigset_t *mask;
        u_long code;
{
        struct osigframe sf;
        struct osigframe *fp;
        struct proc *p;
        struct thread *td;
        struct sigacts *psp;
        struct trapframe *regs;
        int oonstack;

        td = curthread;
        p = td->td_proc;
        PROC_LOCK_ASSERT(p, MA_OWNED);
        psp = p->p_sigacts;
        regs = td->td_frame;
        oonstack = sigonstack(regs->tf_esp);

        /* Allocate space for the signal handler context. */
        if ((p->p_flag & P_ALTSTACK) && !oonstack &&
            SIGISMEMBER(psp->ps_sigonstack, sig)) {
                fp = (struct osigframe *)(p->p_sigstk.ss_sp +
                    p->p_sigstk.ss_size - sizeof(struct osigframe));
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
                p->p_sigstk.ss_flags |= SS_ONSTACK;
#endif
        } else
                fp = (struct osigframe *)regs->tf_esp - 1;
        PROC_UNLOCK(p);

        /* Translate the signal if appropriate. */
        if (p->p_sysent->sv_sigtbl && sig <= p->p_sysent->sv_sigsize)
                sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];

        /* Build the argument list for the signal handler. */
        sf.sf_signum = sig;
        sf.sf_scp = (register_t)&fp->sf_siginfo.si_sc;
        PROC_LOCK(p);
        if (SIGISMEMBER(p->p_sigacts->ps_siginfo, sig)) {
                /* Signal handler installed with SA_SIGINFO. */
                sf.sf_arg2 = (register_t)&fp->sf_siginfo;
                sf.sf_siginfo.si_signo = sig;
                sf.sf_siginfo.si_code = code;
                sf.sf_ahu.sf_action = (__osiginfohandler_t *)catcher;
        } else {
                /* Old FreeBSD-style arguments. */
                sf.sf_arg2 = code;
                sf.sf_addr = regs->tf_err;
                sf.sf_ahu.sf_handler = catcher;
        }
        PROC_UNLOCK(p);

        /* Save most if not all of trap frame. */
        sf.sf_siginfo.si_sc.sc_eax = regs->tf_eax;
        sf.sf_siginfo.si_sc.sc_ebx = regs->tf_ebx;
        sf.sf_siginfo.si_sc.sc_ecx = regs->tf_ecx;
        sf.sf_siginfo.si_sc.sc_edx = regs->tf_edx;
        sf.sf_siginfo.si_sc.sc_esi = regs->tf_esi;
        sf.sf_siginfo.si_sc.sc_edi = regs->tf_edi;
        sf.sf_siginfo.si_sc.sc_cs = regs->tf_cs;
        sf.sf_siginfo.si_sc.sc_ds = regs->tf_ds;
        sf.sf_siginfo.si_sc.sc_ss = regs->tf_ss;
        sf.sf_siginfo.si_sc.sc_es = regs->tf_es;
        sf.sf_siginfo.si_sc.sc_fs = regs->tf_fs;
        sf.sf_siginfo.si_sc.sc_gs = rgs();
        sf.sf_siginfo.si_sc.sc_isp = regs->tf_isp;

        /* Build the signal context to be used by osigreturn(). */
        sf.sf_siginfo.si_sc.sc_onstack = (oonstack) ? 1 : 0;
        SIG2OSIG(*mask, sf.sf_siginfo.si_sc.sc_mask);
        sf.sf_siginfo.si_sc.sc_sp = regs->tf_esp;
        sf.sf_siginfo.si_sc.sc_fp = regs->tf_ebp;
        sf.sf_siginfo.si_sc.sc_pc = regs->tf_eip;
        sf.sf_siginfo.si_sc.sc_ps = regs->tf_eflags;
        sf.sf_siginfo.si_sc.sc_trapno = regs->tf_trapno;
        sf.sf_siginfo.si_sc.sc_err = regs->tf_err;

        /*
         * If we're a vm86 process, we want to save the segment registers.
         * We also change eflags to be our emulated eflags, not the actual
         * eflags.
         */
        if (regs->tf_eflags & PSL_VM) {
                /* XXX confusing names: `tf' isn't a trapframe; `regs' is. */
                struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
                struct vm86_kernel *vm86 = &td->td_pcb->pcb_ext->ext_vm86;

                sf.sf_siginfo.si_sc.sc_gs = tf->tf_vm86_gs;
                sf.sf_siginfo.si_sc.sc_fs = tf->tf_vm86_fs;
                sf.sf_siginfo.si_sc.sc_es = tf->tf_vm86_es;
                sf.sf_siginfo.si_sc.sc_ds = tf->tf_vm86_ds;

                if (vm86->vm86_has_vme == 0)
                        sf.sf_siginfo.si_sc.sc_ps =
                            (tf->tf_eflags & ~(PSL_VIF | PSL_VIP)) |
                            (vm86->vm86_eflags & (PSL_VIF | PSL_VIP));

                /* See sendsig() for comments. */
                tf->tf_eflags &= ~(PSL_VM | PSL_NT | PSL_VIF | PSL_VIP);
        }

        /*
         * Copy the sigframe out to the user's stack.
         */
        if (copyout(&sf, fp, sizeof(*fp)) != 0) {
#ifdef DEBUG
                printf("process %ld has trashed its stack\n", (long)p->p_pid);
#endif
                PROC_LOCK(p);
                sigexit(td, SIGILL);
        }

        regs->tf_esp = (int)fp;
        regs->tf_eip = PS_STRINGS - szosigcode;
        regs->tf_eflags &= ~PSL_T;
        regs->tf_cs = _ucodesel;
        regs->tf_ds = _udatasel;
        regs->tf_es = _udatasel;
        regs->tf_fs = _udatasel;
        load_gs(_udatasel);
        regs->tf_ss = _udatasel;
        PROC_LOCK(p);
}
#endif /* COMPAT_43 */

void
sendsig(catcher, sig, mask, code)
        sig_t catcher;
        int sig;
        sigset_t *mask;
        u_long code;
{
        struct sigframe sf;
        struct proc *p;
        struct thread *td;
        struct sigacts *psp;
        struct trapframe *regs;
        struct sigframe *sfp;
        int oonstack;

        td = curthread;
        p = td->td_proc;
        PROC_LOCK_ASSERT(p, MA_OWNED);
        psp = p->p_sigacts;
#ifdef COMPAT_43
        if (SIGISMEMBER(psp->ps_osigset, sig)) {
                osendsig(catcher, sig, mask, code);
                return;
        }
#endif
        regs = td->td_frame;
        oonstack = sigonstack(regs->tf_esp);

        /* Save user context. */
        bzero(&sf, sizeof(sf));
        sf.sf_uc.uc_sigmask = *mask;
        sf.sf_uc.uc_stack = p->p_sigstk;
        sf.sf_uc.uc_stack.ss_flags = (p->p_flag & P_ALTSTACK)
            ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
        sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0;
        sf.sf_uc.uc_mcontext.mc_gs = rgs();
        bcopy(regs, &sf.sf_uc.uc_mcontext.mc_fs, sizeof(*regs));
        sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext); /* magic */
        get_fpcontext(td, &sf.sf_uc.uc_mcontext);
        fpstate_drop(td);

        /* Allocate space for the signal handler context. */
        if ((p->p_flag & P_ALTSTACK) != 0 && !oonstack &&
            SIGISMEMBER(psp->ps_sigonstack, sig)) {
                sfp = (struct sigframe *)(p->p_sigstk.ss_sp +
                    p->p_sigstk.ss_size - sizeof(struct sigframe));
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
                p->p_sigstk.ss_flags |= SS_ONSTACK;
#endif
        } else
                sfp = (struct sigframe *)regs->tf_esp - 1;
        PROC_UNLOCK(p);

        /* Translate the signal if appropriate. */
        if (p->p_sysent->sv_sigtbl && sig <= p->p_sysent->sv_sigsize)
                sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];

        /* Build the argument list for the signal handler. */
        sf.sf_signum = sig;
        sf.sf_ucontext = (register_t)&sfp->sf_uc;
        PROC_LOCK(p);
        if (SIGISMEMBER(p->p_sigacts->ps_siginfo, sig)) {
                /* Signal handler installed with SA_SIGINFO. */
                sf.sf_siginfo = (register_t)&sfp->sf_si;
                sf.sf_ahu.sf_action = (__siginfohandler_t *)catcher;

                /* Fill in POSIX parts */
                sf.sf_si.si_signo = sig;
                sf.sf_si.si_code = code;
                sf.sf_si.si_addr = (void *)regs->tf_err;
                sf.sf_si.si_pid = p->p_pid;
                sf.sf_si.si_uid = p->p_ucred->cr_uid;
        } else {
                /* Old FreeBSD-style arguments. */
                sf.sf_siginfo = code;
                sf.sf_addr = regs->tf_err;
                sf.sf_ahu.sf_handler = catcher;
        }
        PROC_UNLOCK(p);

        /*
         * If we're a vm86 process, we want to save the segment registers.
         * We also change eflags to be our emulated eflags, not the actual
         * eflags.
         */
        if (regs->tf_eflags & PSL_VM) {
                struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
                struct vm86_kernel *vm86 = &td->td_pcb->pcb_ext->ext_vm86;

                sf.sf_uc.uc_mcontext.mc_gs = tf->tf_vm86_gs;
                sf.sf_uc.uc_mcontext.mc_fs = tf->tf_vm86_fs;
                sf.sf_uc.uc_mcontext.mc_es = tf->tf_vm86_es;
                sf.sf_uc.uc_mcontext.mc_ds = tf->tf_vm86_ds;

                if (vm86->vm86_has_vme == 0)
                        sf.sf_uc.uc_mcontext.mc_eflags =
                            (tf->tf_eflags & ~(PSL_VIF | PSL_VIP)) |
                            (vm86->vm86_eflags & (PSL_VIF | PSL_VIP));

                /*
                 * Clear PSL_NT to inhibit T_TSSFLT faults on return from
                 * syscalls made by the signal handler.  This just avoids
                 * wasting time for our lazy fixup of such faults.  PSL_NT
                 * does nothing in vm86 mode, but vm86 programs can set it
                 * almost legitimately in probes for old cpu types.
                 */
                tf->tf_eflags &= ~(PSL_VM | PSL_NT | PSL_VIF | PSL_VIP);
        }

        /*
         * Copy the sigframe out to the user's stack.
         */
        if (copyout(&sf, sfp, sizeof(*sfp)) != 0) {
#ifdef DEBUG
                printf("process %ld has trashed its stack\n", (long)p->p_pid);
#endif
                PROC_LOCK(p);
                sigexit(td, SIGILL);
        }

        regs->tf_esp = (int)sfp;
        regs->tf_eip = PS_STRINGS - *(p->p_sysent->sv_szsigcode);
        regs->tf_eflags &= ~PSL_T;
        regs->tf_cs = _ucodesel;
        regs->tf_ds = _udatasel;
        regs->tf_es = _udatasel;
        regs->tf_fs = _udatasel;
        regs->tf_ss = _udatasel;
        PROC_LOCK(p);
}

/*
 * 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.
 *
 * MPSAFE
 */
int
osigreturn(td, uap)
        struct thread *td;
        struct osigreturn_args /* {
                struct osigcontext *sigcntxp;
        } */ *uap;
{
#ifdef COMPAT_43
        struct osigcontext sc;
        struct trapframe *regs;
        struct osigcontext *scp;
        struct proc *p = td->td_proc;
        int eflags, error;

        regs = td->td_frame;
        error = copyin(uap->sigcntxp, &sc, sizeof(sc));
        if (error != 0)
                return (error);
        scp = &sc;
        eflags = scp->sc_ps;
        if (eflags & PSL_VM) {
                struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
                struct vm86_kernel *vm86;

                /*
                 * if pcb_ext == 0 or vm86_inited == 0, the user hasn't
                 * set up the vm86 area, and we can't enter vm86 mode.
                 */
                if (td->td_pcb->pcb_ext == 0)
                        return (EINVAL);
                vm86 = &td->td_pcb->pcb_ext->ext_vm86;
                if (vm86->vm86_inited == 0)
                        return (EINVAL);

                /* Go back to user mode if both flags are set. */
                if ((eflags & PSL_VIP) && (eflags & PSL_VIF))
                        trapsignal(p, SIGBUS, 0);

                if (vm86->vm86_has_vme) {
                        eflags = (tf->tf_eflags & ~VME_USERCHANGE) |
                            (eflags & VME_USERCHANGE) | PSL_VM;
                } else {
                        vm86->vm86_eflags = eflags;     /* save VIF, VIP */
                        eflags = (tf->tf_eflags & ~VM_USERCHANGE) |
                            (eflags & VM_USERCHANGE) | PSL_VM;
                }
                tf->tf_vm86_ds = scp->sc_ds;
                tf->tf_vm86_es = scp->sc_es;
                tf->tf_vm86_fs = scp->sc_fs;
                tf->tf_vm86_gs = scp->sc_gs;
                tf->tf_ds = _udatasel;
                tf->tf_es = _udatasel;
                tf->tf_fs = _udatasel;
        } else {
                /*
                 * Don't allow users to change privileged or reserved flags.
                 */
                /*
                 * 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 (!EFL_SECURE(eflags & ~PSL_RF, regs->tf_eflags & ~PSL_RF)) {
                        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.
                 */
                if (!CS_SECURE(scp->sc_cs)) {
                        trapsignal(p, SIGBUS, T_PROTFLT);
                        return (EINVAL);
                }
                regs->tf_ds = scp->sc_ds;
                regs->tf_es = scp->sc_es;
                regs->tf_fs = scp->sc_fs;
        }

        /* Restore remaining registers. */
        regs->tf_eax = scp->sc_eax;
        regs->tf_ebx = scp->sc_ebx;
        regs->tf_ecx = scp->sc_ecx;
        regs->tf_edx = scp->sc_edx;
        regs->tf_esi = scp->sc_esi;
        regs->tf_edi = scp->sc_edi;
        regs->tf_cs = scp->sc_cs;
        regs->tf_ss = scp->sc_ss;
        regs->tf_isp = scp->sc_isp;
        regs->tf_ebp = scp->sc_fp;
        regs->tf_esp = scp->sc_sp;
        regs->tf_eip = scp->sc_pc;
        regs->tf_eflags = eflags;

        PROC_LOCK(p);
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
        if (scp->sc_onstack & 1)
                p->p_sigstk.ss_flags |= SS_ONSTACK;
        else
                p->p_sigstk.ss_flags &= ~SS_ONSTACK;
#endif
        SIGSETOLD(p->p_sigmask, scp->sc_mask);
        SIG_CANTMASK(p->p_sigmask);
        signotify(p);
        PROC_UNLOCK(p);
        return (EJUSTRETURN);
#else /* !COMPAT_43 */
        return (ENOSYS);
#endif /* COMPAT_43 */
}

/*
 * MPSAFE
 */
int
sigreturn(td, uap)
        struct thread *td;
        struct sigreturn_args /* {
                const __ucontext *sigcntxp;
        } */ *uap;
{
        ucontext_t uc;
        struct proc *p = td->td_proc;
        struct trapframe *regs;
        const ucontext_t *ucp;
        int cs, eflags, error, ret;

        error = copyin(uap->sigcntxp, &uc, sizeof(uc));
        if (error != 0)
                return (error);
        ucp = &uc;
        regs = td->td_frame;
        eflags = ucp->uc_mcontext.mc_eflags;
        if (eflags & PSL_VM) {
                struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
                struct vm86_kernel *vm86;

                /*
                 * if pcb_ext == 0 or vm86_inited == 0, the user hasn't
                 * set up the vm86 area, and we can't enter vm86 mode.
                 */
                if (td->td_pcb->pcb_ext == 0)
                        return (EINVAL);
                vm86 = &td->td_pcb->pcb_ext->ext_vm86;
                if (vm86->vm86_inited == 0)
                        return (EINVAL);

                /* Go back to user mode if both flags are set. */
                if ((eflags & PSL_VIP) && (eflags & PSL_VIF))
                        trapsignal(p, SIGBUS, 0);

                if (vm86->vm86_has_vme) {
                        eflags = (tf->tf_eflags & ~VME_USERCHANGE) |
                            (eflags & VME_USERCHANGE) | PSL_VM;
                } else {
                        vm86->vm86_eflags = eflags;     /* save VIF, VIP */
                        eflags = (tf->tf_eflags & ~VM_USERCHANGE) |
                            (eflags & VM_USERCHANGE) | PSL_VM;
                }
                bcopy(&ucp->uc_mcontext.mc_fs, tf, sizeof(struct trapframe));
                tf->tf_eflags = eflags;
                tf->tf_vm86_ds = tf->tf_ds;
                tf->tf_vm86_es = tf->tf_es;
                tf->tf_vm86_fs = tf->tf_fs;
                tf->tf_vm86_gs = ucp->uc_mcontext.mc_gs;
                tf->tf_ds = _udatasel;
                tf->tf_es = _udatasel;
                tf->tf_fs = _udatasel;
        } else {
                /*
                 * Don't allow users to change privileged or reserved flags.
                 */
                /*
                 * 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 (!EFL_SECURE(eflags & ~PSL_RF, regs->tf_eflags & ~PSL_RF)) {
                        printf("sigreturn: eflags = 0x%x\n", eflags);
                        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.
                 */
                cs = ucp->uc_mcontext.mc_cs;
                if (!CS_SECURE(cs)) {
                        printf("sigreturn: cs = 0x%x\n", cs);
                        trapsignal(p, SIGBUS, T_PROTFLT);
                        return (EINVAL);
                }

                ret = set_fpcontext(td, &ucp->uc_mcontext);
                if (ret != 0)
                        return (ret);
                bcopy(&ucp->uc_mcontext.mc_fs, regs, sizeof(*regs));
        }

        PROC_LOCK(p);
#if defined(COMPAT_43) || defined(COMPAT_SUNOS)
        if (ucp->uc_mcontext.mc_onstack & 1)
                p->p_sigstk.ss_flags |= SS_ONSTACK;
        else
                p->p_sigstk.ss_flags &= ~SS_ONSTACK;
#endif

        p->p_sigmask = ucp->uc_sigmask;
        SIG_CANTMASK(p->p_sigmask);
        signotify(p);
        PROC_UNLOCK(p);
        return (EJUSTRETURN);
}

/*
 * Machine dependent boot() routine
 *
 * I haven't seen anything to put here yet
 * Possibly some stuff might be grafted back here from boot()
 */
void
cpu_boot(int howto)
{
}

/*
 * Shutdown the CPU as much as possible
 */
void
cpu_halt(void)
{
        for (;;)
                __asm__ ("hlt");
}

/*
 * Hook to idle the CPU when possible.  In the SMP case we default to
 * off because a halted cpu will not currently pick up a new thread in the
 * run queue until the next timer tick.  If turned on this will result in
 * approximately a 4.2% loss in real time performance in buildworld tests
 * (but improves user and sys times oddly enough), and saves approximately
 * 5% in power consumption on an idle machine (tests w/2xCPU 1.1GHz P3).
 *
 * XXX we need to have a cpu mask of idle cpus and generate an IPI or
 * otherwise generate some sort of interrupt to wake up cpus sitting in HLT.
 * Then we can have our cake and eat it too.
 */
#ifdef SMP
static int      cpu_idle_hlt = 0;
#else
static int      cpu_idle_hlt = 1;
#endif
SYSCTL_INT(_machdep, OID_AUTO, cpu_idle_hlt, CTLFLAG_RW,
    &cpu_idle_hlt, 0, "Idle loop HLT enable");

/*
 * Note that we have to be careful here to avoid a race between checking
 * sched_runnable() and actually halting.  If we don't do this, we may waste
 * the time between calling hlt and the next interrupt even though there
 * is a runnable process.
 */
void
cpu_idle(void)
{
        if (cpu_idle_hlt) {
                disable_intr();
                if (sched_runnable()) {
                        enable_intr();
                } else {
                        /*
                         * we must absolutely guarentee that hlt is the
                         * absolute next instruction after sti or we
                         * introduce a timing window.
                         */
                        __asm __volatile("sti; hlt");
                }
        }
}

/*
 * Clear registers on exec
 */
void
exec_setregs(td, entry, stack, ps_strings)
        struct thread *td;
        u_long entry;
        u_long stack;
        u_long ps_strings;
{
        struct trapframe *regs = td->td_frame;
        struct pcb *pcb = td->td_pcb;

        /* Reset pc->pcb_gs and %gs before possibly invalidating it. */
        pcb->pcb_gs = _udatasel;
        load_gs(_udatasel);

        if (td->td_proc->p_md.md_ldt)
                user_ldt_free(td);
  
        bzero((char *)regs, sizeof(struct trapframe));
        regs->tf_eip = entry;
        regs->tf_esp = stack;
        regs->tf_eflags = PSL_USER | (regs->tf_eflags & PSL_T);
        regs->tf_ss = _udatasel;
        regs->tf_ds = _udatasel;
        regs->tf_es = _udatasel;
        regs->tf_fs = _udatasel;
        regs->tf_cs = _ucodesel;

        /* PS_STRINGS value for BSD/OS binaries.  It is 0 for non-BSD/OS. */
        regs->tf_ebx = ps_strings;

        /*
         * Reset the hardware debug registers if they were in use.
         * They won't have any meaning for the newly exec'd process.  
         */
        if (pcb->pcb_flags & PCB_DBREGS) {
                pcb->pcb_dr0 = 0;
                pcb->pcb_dr1 = 0;
                pcb->pcb_dr2 = 0;
                pcb->pcb_dr3 = 0;
                pcb->pcb_dr6 = 0;
                pcb->pcb_dr7 = 0;
                if (pcb == PCPU_GET(curpcb)) {
                        /*
                         * Clear the debug registers on the running
                         * CPU, otherwise they will end up affecting
                         * the next process we switch to.
                         */
                        reset_dbregs();
                }
                pcb->pcb_flags &= ~PCB_DBREGS;
        }

        /*
         * Initialize the math emulator (if any) for the current process.
         * Actually, just clear the bit that says that the emulator has
         * been initialized.  Initialization is delayed until the process
         * traps to the emulator (if it is done at all) mainly because
         * emulators don't provide an entry point for initialization.
         */
        td->td_pcb->pcb_flags &= ~FP_SOFTFP;

        /*
         * Arrange to trap the next npx or `fwait' instruction (see npx.c
         * for why fwait must be trapped at least if there is an npx or an
         * emulator).  This is mainly to handle the case where npx0 is not
         * configured, since the npx routines normally set up the trap
         * otherwise.  It should be done only at boot time, but doing it
         * here allows modifying `npx_exists' for testing the emulator on
         * systems with an npx.
         */
        load_cr0(rcr0() | CR0_MP | CR0_TS);

        /* Initialize the npx (if any) for the current process. */
        /*
         * XXX the above load_cr0() also initializes it and is a layering
         * violation if NPX is configured.  It drops the npx partially
         * and this would be fatal if we were interrupted now, and decided
         * to force the state to the pcb, and checked the invariant
         * (CR0_TS clear) if and only if PCPU_GET(fpcurthread) != NULL).
         * ALL of this can happen except the check.  The check used to
         * happen and be fatal later when we didn't complete the drop
         * before returning to user mode.  This should be fixed properly
         * soon.
         */
        fpstate_drop(td);

        /*
         * XXX - Linux emulator
         * Make sure sure edx is 0x0 on entry. Linux binaries depend
         * on it.
         */
        td->td_retval[1] = 0;
}

void
cpu_setregs(void)
{
        unsigned int cr0;

        cr0 = rcr0();
#ifdef SMP
        cr0 |= CR0_NE;                  /* Done by npxinit() */
#endif
        cr0 |= CR0_MP | CR0_TS;         /* Done at every execve() too. */
#ifndef I386_CPU
        cr0 |= CR0_WP | CR0_AM;
#endif
        load_cr0(cr0);
        load_gs(_udatasel);
}

static int
sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
{
        int error;
        error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2,
                req);
        if (!error && req->newptr)
                resettodr();
        return (error);
}

SYSCTL_PROC(_machdep, CPU_ADJKERNTZ, adjkerntz, CTLTYPE_INT|CTLFLAG_RW,
        &adjkerntz, 0, sysctl_machdep_adjkerntz, "I", "");

SYSCTL_INT(_machdep, CPU_DISRTCSET, disable_rtc_set,
        CTLFLAG_RW, &disable_rtc_set, 0, "");

SYSCTL_STRUCT(_machdep, CPU_BOOTINFO, bootinfo, 
        CTLFLAG_RD, &bootinfo, bootinfo, "");

SYSCTL_INT(_machdep, CPU_WALLCLOCK, wall_cmos_clock,
        CTLFLAG_RW, &wall_cmos_clock, 0, "");

u_long bootdev;         /* not a dev_t - encoding is different */
SYSCTL_ULONG(_machdep, OID_AUTO, guessed_bootdev,
        CTLFLAG_RD, &bootdev, 0, "Maybe the Boot device (not in dev_t format)");

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

/*
 * Initialize segments & interrupt table
 */

int _default_ldt;
union descriptor gdt[NGDT * MAXCPU];    /* global descriptor table */
static struct gate_descriptor idt0[NIDT];
struct gate_descriptor *idt = &idt0[0]; /* interrupt descriptor table */
union descriptor ldt[NLDT];             /* local descriptor table */
#ifdef SMP
/* table descriptors - used to load tables by microp */
struct region_descriptor r_gdt, r_idt;
#endif

int private_tss;                        /* flag indicating private tss */

#if defined(I586_CPU) && !defined(NO_F00F_HACK)
extern int has_f00f_bug;
#endif

static struct i386tss dblfault_tss;
static char dblfault_stack[PAGE_SIZE];

extern  struct user     *proc0uarea;
extern  vm_offset_t     proc0kstack;


/* 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)*/ },
/* GPRIV_SEL    3 SMP Per-Processor Private Data Descriptor */
{       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)*/ },
/* GPROC0_SEL   4 Proc 0 Tss Descriptor */
{
        0x0,                    /* segment base address */
        sizeof(struct i386tss)-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)*/ },
/* GLDT_SEL     5 LDT Descriptor */
{       (int) ldt,              /* segment base address  */
        sizeof(ldt)-1,          /* length - all address space */
        SDT_SYSLDT,             /* segment type */
        SEL_UPL,                /* 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 6 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)*/ },
/* GTGATE_SEL   7 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)*/ },
/* GBIOSLOWMEM_SEL 8 BIOS access to realmode segment 0x40, must be #8 in GDT */
{       0x400,                  /* segment base address */
        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)*/ },
/* GPANIC_SEL   9 Panic Tss Descriptor */
{       (int) &dblfault_tss,    /* segment base address  */
        sizeof(struct i386tss)-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)*/ },
/* GBIOSCODE32_SEL 10 BIOS 32-bit interface (32bit Code) */
{       0,                      /* segment base address (overwritten)  */
        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)*/ },
/* GBIOSCODE16_SEL 11 BIOS 32-bit interface (16bit Code) */
{       0,                      /* segment base address (overwritten)  */
        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)*/ },
/* GBIOSDATA_SEL 12 BIOS 32-bit interface (Data) */
{       0,                      /* segment base address (overwritten) */
        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)*/ },
/* GBIOSUTIL_SEL 13 BIOS 16-bit interface (Utility) */
{       0,                      /* segment base address (overwritten) */
        0xfffff,                /* length */
        SDT_MEMRWA,             /* 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)*/ },
/* GBIOSARGS_SEL 14 BIOS 16-bit interface (Arguments) */
{       0,                      /* segment base address (overwritten) */
        0xfffff,                /* length */
        SDT_MEMRWA,             /* 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)*/ },
};

static 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)*/ },
        /* 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)*/ },
        /* 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, selec)
        int idx;
        inthand_t *func;
        int typ;
        int dpl;
        int selec;
{
        struct gate_descriptor *ip;

        ip = idt + idx;
        ip->gd_looffset = (int)func;
        ip->gd_selector = selec;
        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(fpusegm),
        IDTVEC(tss), IDTVEC(missing), IDTVEC(stk), IDTVEC(prot),
        IDTVEC(page), IDTVEC(mchk), IDTVEC(rsvd), IDTVEC(fpu), IDTVEC(align),
        IDTVEC(xmm), IDTVEC(lcall_syscall), IDTVEC(int0x80_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;
}

#define PHYSMAP_SIZE    (2 * 8)

/*
 * Populate the (physmap) array with base/bound pairs describing the
 * available physical memory in the system, then test this memory and
 * build the phys_avail array describing the actually-available memory.
 *
 * If we cannot accurately determine the physical memory map, then use
 * value from the 0xE801 call, and failing that, the RTC.
 *
 * Total memory size may be set by the kernel environment variable
 * hw.physmem or the compile-time define MAXMEM.
 */
static void
getmemsize(int first)
{
        int i, physmap_idx, pa_indx;
        u_int basemem, extmem;
        struct vm86frame vmf;
        struct vm86context vmc;
        vm_offset_t pa, physmap[PHYSMAP_SIZE];
        pt_entry_t *pte;
        char *cp;
        struct bios_smap *smap;

        bzero(&vmf, sizeof(struct vm86frame));
        bzero(physmap, sizeof(physmap));
        basemem = 0;

        /*
         * map page 1 R/W into the kernel page table so we can use it
         * as a buffer.  The kernel will unmap this page later.
         */
        pmap_kenter(KERNBASE + (1 << PAGE_SHIFT), 1);

        /*
         * get memory map with INT 15:E820
         */
        vmc.npages = 0;
        smap = (void *)vm86_addpage(&vmc, 1, KERNBASE + (1 << PAGE_SHIFT));
        vm86_getptr(&vmc, (vm_offset_t)smap, &vmf.vmf_es, &vmf.vmf_di);

        physmap_idx = 0;
        vmf.vmf_ebx = 0;
        do {
                vmf.vmf_eax = 0xE820;
                vmf.vmf_edx = SMAP_SIG;
                vmf.vmf_ecx = sizeof(struct bios_smap);
                i = vm86_datacall(0x15, &vmf, &vmc);
                if (i || vmf.vmf_eax != SMAP_SIG)
                        break;
                if (boothowto & RB_VERBOSE)
                        printf("SMAP type=%02x base=%08x %08x len=%08x %08x\n",
                                smap->type,
                                *(u_int32_t *)((char *)&smap->base + 4),
                                (u_int32_t)smap->base,
                                *(u_int32_t *)((char *)&smap->length + 4),
                                (u_int32_t)smap->length);

                if (smap->type != 0x01)
                        goto next_run;

                if (smap->length == 0)
                        goto next_run;

                if (smap->base >= 0xffffffff) {
                        printf("%uK of memory above 4GB ignored\n",
                            (u_int)(smap->length / 1024));
                        goto next_run;
                }

                for (i = 0; i <= physmap_idx; i += 2) {
                        if (smap->base < physmap[i + 1]) {
                                if (boothowto & RB_VERBOSE)
                                        printf(
        "Overlapping or non-montonic memory region, ignoring second region\n");
                                goto next_run;
                        }
                }

                if (smap->base == physmap[physmap_idx + 1]) {
                        physmap[physmap_idx + 1] += smap->length;
                        goto next_run;
                }

                physmap_idx += 2;
                if (physmap_idx == PHYSMAP_SIZE) {
                        printf(
                "Too many segments in the physical address map, giving up\n");
                        break;
                }
                physmap[physmap_idx] = smap->base;
                physmap[physmap_idx + 1] = smap->base + smap->length;
next_run: ;
        } while (vmf.vmf_ebx != 0);

        /*
         * Perform "base memory" related probes & setup
         */
        for (i = 0; i <= physmap_idx; i += 2) {
                if (physmap[i] == 0x00000000) {
                        basemem = physmap[i + 1] / 1024;
                        break;
                }
        }

        /* Fall back to the old compatibility function for base memory */
        if (basemem == 0) {
                vm86_intcall(0x12, &vmf);
                basemem = vmf.vmf_ax;
        }

        if (basemem > 640) {
                printf("Preposterous BIOS basemem of %uK, truncating to 640K\n",
                        basemem);
                basemem = 640;
        }

        /*
         * XXX if biosbasemem is now < 640, there is a `hole'
         * between the end of base memory and the start of
         * ISA memory.  The hole may be empty or it may
         * contain BIOS code or data.  Map it read/write so
         * that the BIOS can write to it.  (Memory from 0 to
         * the physical end of the kernel is mapped read-only
         * to begin with and then parts of it are remapped.
         * The parts that aren't remapped form holes that
         * remain read-only and are unused by the kernel.
         * The base memory area is below the physical end of
         * the kernel and right now forms a read-only hole.
         * The part of it from PAGE_SIZE to
         * (trunc_page(biosbasemem * 1024) - 1) will be
         * remapped and used by the kernel later.)
         *
         * This code is similar to the code used in
         * pmap_mapdev, but since no memory needs to be
         * allocated we simply change the mapping.
         */
        for (pa = trunc_page(basemem * 1024);
             pa < ISA_HOLE_START; pa += PAGE_SIZE)
                pmap_kenter(KERNBASE + pa, pa);

        /*
         * if basemem != 640, map pages r/w into vm86 page table so
         * that the bios can scribble on it.
         */
        pte = (pt_entry_t *)vm86paddr;
        for (i = basemem / 4; i < 160; i++)
                pte[i] = (i << PAGE_SHIFT) | PG_V | PG_RW | PG_U;

        if (physmap[1] != 0)
                goto physmap_done;

        /*
         * If we failed above, try memory map with INT 15:E801
         */
        vmf.vmf_ax = 0xE801;
        if (vm86_intcall(0x15, &vmf) == 0) {
                extmem = vmf.vmf_cx + vmf.vmf_dx * 64;
        } else {
#if 0
                vmf.vmf_ah = 0x88;
                vm86_intcall(0x15, &vmf);
                extmem = vmf.vmf_ax;
#else
                /*
                 * Prefer the RTC value for extended memory.
                 */
                extmem = rtcin(RTC_EXTLO) + (rtcin(RTC_EXTHI) << 8);
#endif
        }

        /*
         * 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 ((extmem > 15 * 1024) && (extmem < 16 * 1024))
                extmem = 15 * 1024;

        physmap[0] = 0;
        physmap[1] = basemem * 1024;
        physmap_idx = 2;
        physmap[physmap_idx] = 0x100000;
        physmap[physmap_idx + 1] = physmap[physmap_idx] + extmem * 1024;

physmap_done:
        /*
         * Now, physmap contains a map of physical memory.
         */

#ifdef SMP
        /* make hole for AP bootstrap code */
        physmap[1] = mp_bootaddress(physmap[1] / 1024);

        /* look for the MP hardware - needed for apic addresses */
        i386_mp_probe();
#endif

        /*
         * Maxmem isn't the "maximum memory", it's one larger than the
         * highest page of the physical address space.  It should be
         * called something like "Maxphyspage".  We may adjust this 
         * based on ``hw.physmem'' and the results of the memory test.
         */
        Maxmem = atop(physmap[physmap_idx + 1]);

#ifdef MAXMEM
        Maxmem = MAXMEM / 4;
#endif

        /*
         * hw.physmem is a size in bytes; we also allow k, m, and g suffixes
         * for the appropriate modifiers.  This overrides MAXMEM.
         */
        if ((cp = getenv("hw.physmem")) != NULL) {
                u_int64_t AllowMem, sanity;
                char *ep;

                sanity = AllowMem = strtouq(cp, &ep, 0);
                if ((ep != cp) && (*ep != 0)) {
                        switch(*ep) {
                        case 'g':
                        case 'G':
                                AllowMem <<= 10;
                        case 'm':
                        case 'M':
                                AllowMem <<= 10;
                        case 'k':
                        case 'K':
                                AllowMem <<= 10;
                                break;
                        default:
                                AllowMem = sanity = 0;
                        }
                        if (AllowMem < sanity)
                                AllowMem = 0;
                }
                if (AllowMem == 0)
                        printf("Ignoring invalid memory size of '%s'\n", cp);
                else
                        Maxmem = atop(AllowMem);
                freeenv(cp);
        }

        if (atop(physmap[physmap_idx + 1]) != Maxmem &&
            (boothowto & RB_VERBOSE))
                printf("Physical memory use set to %ldK\n", Maxmem * 4);

        /*
         * If Maxmem has been increased beyond what the system has detected,
         * extend the last memory segment to the new limit.
         */ 
        if (atop(physmap[physmap_idx + 1]) < Maxmem)
                physmap[physmap_idx + 1] = ptoa(Maxmem);

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

        /*
         * Size up each available chunk of physical memory.
         */
        physmap[0] = PAGE_SIZE;         /* mask off page 0 */
        pa_indx = 0;
        phys_avail[pa_indx++] = physmap[0];
        phys_avail[pa_indx] = physmap[0];
        pte = CMAP1;

        /*
         * physmap is in bytes, so when converting to page boundaries,
         * round up the start address and round down the end address.
         */
        for (i = 0; i <= physmap_idx; i += 2) {
                vm_offset_t end;

                end = ptoa(Maxmem);
                if (physmap[i + 1] < end)
                        end = trunc_page(physmap[i + 1]);
                for (pa = round_page(physmap[i]); pa < end; pa += PAGE_SIZE) {
                        int tmp, page_bad;
                        int *ptr = (int *)CADDR1;

                        /*
                         * block out kernel memory as not available.
                         */
                        if (pa >= 0x100000 && pa < first)
                                continue;
        
                        page_bad = FALSE;

                        /*
                         * map page into kernel: valid, read/write,non-cacheable
                         */
                        *pte = pa | PG_V | PG_RW | PG_N;
                        invltlb();

                        tmp = *(int *)ptr;
                        /*
                         * Test for alternating 1's and 0's
                         */
                        *(volatile int *)ptr = 0xaaaaaaaa;
                        if (*(volatile int *)ptr != 0xaaaaaaaa) {
                                page_bad = TRUE;
                        }
                        /*
                         * Test for alternating 0's and 1's
                         */
                        *(volatile int *)ptr = 0x55555555;
                        if (*(volatile int *)ptr != 0x55555555) {
                        page_bad = TRUE;
                        }
                        /*
                         * Test for all 1's
                         */
                        *(volatile int *)ptr = 0xffffffff;
                        if (*(volatile int *)ptr != 0xffffffff) {
                                page_bad = TRUE;
                        }
                        /*
                         * Test for all 0's
                         */
                        *(volatile int *)ptr = 0x0;
                        if (*(volatile int *)ptr != 0x0) {
                                page_bad = TRUE;
                        }
                        /*
                         * Restore original value.
                         */
                        *(int *)ptr = tmp;

                        /*
                         * Adjust array of valid/good pages.
                         */
                        if (page_bad == TRUE) {
                                continue;
                        }
                        /*
                         * If this good page is a continuation of the
                         * previous set of good pages, then just increase
                         * the end pointer. Otherwise start a new chunk.
                         * Note that "end" points one higher than end,
                         * making the range >= start and < end.
                         * If we're also doing a speculative memory
                         * test and we at or past the end, bump up Maxmem
                         * so that we keep going. The first bad page
                         * will terminate the loop.
                         */
                        if (phys_avail[pa_indx] == pa) {
                                phys_avail[pa_indx] += PAGE_SIZE;
                        } else {
                                pa_indx++;
                                if (pa_indx == PHYS_AVAIL_ARRAY_END) {
                                        printf(
                "Too many holes in the physical address space, giving up\n");
                                        pa_indx--;
                                        break;
                                }
                                phys_avail[pa_indx++] = pa;     /* start */
                                phys_avail[pa_indx] = pa + PAGE_SIZE;   /* end */
                        }
                        physmem++;
                }
        }
        *pte = 0;
        invltlb();

        /*
         * XXX
         * The last chunk must contain at least one page plus the message
         * buffer to avoid complicating other code (message buffer address
         * calculation, etc.).
         */
        while (phys_avail[pa_indx - 1] + PAGE_SIZE +
            round_page(MSGBUF_SIZE) >= phys_avail[pa_indx]) {
                physmem -= atop(phys_avail[pa_indx] - phys_avail[pa_indx - 1]);
                phys_avail[pa_indx--] = 0;
                phys_avail[pa_indx--] = 0;
        }

        Maxmem = atop(phys_avail[pa_indx]);

        /* Trim off space for the message buffer. */
        phys_avail[pa_indx] -= round_page(MSGBUF_SIZE);

        avail_end = phys_avail[pa_indx];
}

void
init386(first)
        int first;
{
        struct gate_descriptor *gdp;
        int gsel_tss, metadata_missing, off, x;
#ifndef SMP
        /* table descriptors - used to load tables by microp */
        struct region_descriptor r_gdt, r_idt;
#endif
        struct pcpu *pc;

        proc0.p_uarea = proc0uarea;
        thread0.td_kstack = proc0kstack;
        thread0.td_pcb = (struct pcb *)
           (thread0.td_kstack + KSTACK_PAGES * PAGE_SIZE) - 1;
        atdevbase = ISA_HOLE_START + KERNBASE;

        /*
         * This may be done better later if it gets more high level
         * components in it. If so just link td->td_proc here.
         */
        proc_linkup(&proc0, &ksegrp0, &kse0, &thread0);

        metadata_missing = 0;
        if (bootinfo.bi_modulep) {
                preload_metadata = (caddr_t)bootinfo.bi_modulep + KERNBASE;
                preload_bootstrap_relocate(KERNBASE);
        } else {
                metadata_missing = 1;
        }
        if (envmode == 1)
                kern_envp = static_env;
        else if (bootinfo.bi_envp)
                kern_envp = (caddr_t)bootinfo.bi_envp + KERNBASE;

        /* Init basic tunables, hz etc */
        init_param1();

        /*
         * 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(round_page(etext)) - 1.
         */
        gdt_segs[GCODE_SEL].ssd_limit = atop(0 - 1);
        gdt_segs[GDATA_SEL].ssd_limit = atop(0 - 1);
#ifdef SMP
        pc = &SMP_prvspace[0].pcpu;
        gdt_segs[GPRIV_SEL].ssd_limit =
                atop(sizeof(struct privatespace) - 1);
#else
        pc = &__pcpu;
        gdt_segs[GPRIV_SEL].ssd_limit =
                atop(sizeof(struct pcpu) - 1);
#endif
        gdt_segs[GPRIV_SEL].ssd_base = (int) pc;
        gdt_segs[GPROC0_SEL].ssd_base = (int) &pc->pc_common_tss;

        for (x = 0; x < NGDT; x++) {
#ifdef BDE_DEBUGGER
                /* avoid overwriting db entries with APM ones */
                if (x >= GAPMCODE32_SEL && x <= GAPMDATA_SEL)
                        continue;
#endif
                ssdtosd(&gdt_segs[x], &gdt[x].sd);
        }

        r_gdt.rd_limit = NGDT * sizeof(gdt[0]) - 1;
        r_gdt.rd_base =  (int) gdt;
        lgdt(&r_gdt);

        pcpu_init(pc, 0, sizeof(struct pcpu));
        PCPU_SET(prvspace, pc);
        PCPU_SET(curthread, &thread0);

        /*
         * Initialize mutexes.
         *
         * icu_lock: in order to allow an interrupt to occur in a critical
         *           section, to set pcpu->ipending (etc...) properly, we
         *           must be able to get the icu lock, so it can't be
         *           under witness.
         */
        mutex_init();
        mtx_init(&clock_lock, "clk", NULL, MTX_SPIN | MTX_RECURSE);
        mtx_init(&icu_lock, "icu", NULL, MTX_SPIN | MTX_NOWITNESS);

        /* make ldt memory segments */
        /*
         * XXX - VM_MAXUSER_ADDRESS is an end address, not a max.  And it
         * should be spelled ...MAX_USER...
         */
        ldt_segs[LUCODE_SEL].ssd_limit = atop(VM_MAXUSER_ADDRESS - 1);
        ldt_segs[LUDATA_SEL].ssd_limit = atop(VM_MAXUSER_ADDRESS - 1);
        for (x = 0; x < sizeof ldt_segs / sizeof ldt_segs[0]; x++)
                ssdtosd(&ldt_segs[x], &ldt[x].sd);

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

        /* exceptions */
        for (x = 0; x < NIDT; x++)
                setidt(x, &IDTVEC(rsvd), SDT_SYS386TGT, SEL_KPL,
                    GSEL(GCODE_SEL, SEL_KPL));
        setidt(0, &IDTVEC(div),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(1, &IDTVEC(dbg),  SDT_SYS386IGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(2, &IDTVEC(nmi),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(3, &IDTVEC(bpt),  SDT_SYS386IGT, SEL_UPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(4, &IDTVEC(ofl),  SDT_SYS386TGT, SEL_UPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(5, &IDTVEC(bnd),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(6, &IDTVEC(ill),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(7, &IDTVEC(dna),  SDT_SYS386TGT, SEL_KPL
            , GSEL(GCODE_SEL, SEL_KPL));
        setidt(8, 0,  SDT_SYSTASKGT, SEL_KPL, GSEL(GPANIC_SEL, SEL_KPL));
        setidt(9, &IDTVEC(fpusegm),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(10, &IDTVEC(tss),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(11, &IDTVEC(missing),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(12, &IDTVEC(stk),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(13, &IDTVEC(prot),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(14, &IDTVEC(page),  SDT_SYS386IGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(15, &IDTVEC(rsvd),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(16, &IDTVEC(fpu),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(17, &IDTVEC(align), SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(18, &IDTVEC(mchk),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(19, &IDTVEC(xmm), SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(0x80, &IDTVEC(int0x80_syscall), SDT_SYS386TGT, SEL_UPL,
            GSEL(GCODE_SEL, SEL_KPL));

        r_idt.rd_limit = sizeof(idt0) - 1;
        r_idt.rd_base = (int) idt;
        lidt(&r_idt);

        /*
         * Initialize the console before we print anything out.
         */
        cninit();

        if (metadata_missing)
                printf("WARNING: loader(8) metadata is missing!\n");

#ifdef DEV_ISA
        isa_defaultirq();
#endif

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

        finishidentcpu();       /* Final stage of CPU initialization */
        setidt(6, &IDTVEC(ill),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        setidt(13, &IDTVEC(prot),  SDT_SYS386TGT, SEL_KPL,
            GSEL(GCODE_SEL, SEL_KPL));
        initializecpu();        /* Initialize CPU registers */

        /* make an initial tss so cpu can get interrupt stack on syscall! */
        /* Note: -16 is so we can grow the trapframe if we came from vm86 */
        PCPU_SET(common_tss.tss_esp0, thread0.td_kstack +
            KSTACK_PAGES * PAGE_SIZE - sizeof(struct pcb) - 16);
        PCPU_SET(common_tss.tss_ss0, GSEL(GDATA_SEL, SEL_KPL));
        gsel_tss = GSEL(GPROC0_SEL, SEL_KPL);
        private_tss = 0;
        PCPU_SET(tss_gdt, &gdt[GPROC0_SEL].sd);
        PCPU_SET(common_tssd, *PCPU_GET(tss_gdt));
        PCPU_SET(common_tss.tss_ioopt, (sizeof (struct i386tss)) << 16);
        ltr(gsel_tss);

        dblfault_tss.tss_esp = dblfault_tss.tss_esp0 = dblfault_tss.tss_esp1 =
            dblfault_tss.tss_esp2 = (int)&dblfault_stack[sizeof(dblfault_stack)];
        dblfault_tss.tss_ss = dblfault_tss.tss_ss0 = dblfault_tss.tss_ss1 =
            dblfault_tss.tss_ss2 = GSEL(GDATA_SEL, SEL_KPL);
        dblfault_tss.tss_cr3 = (int)IdlePTD;
        dblfault_tss.tss_eip = (int)dblfault_handler;
        dblfault_tss.tss_eflags = PSL_KERNEL;
        dblfault_tss.tss_ds = dblfault_tss.tss_es =
            dblfault_tss.tss_gs = GSEL(GDATA_SEL, SEL_KPL);
        dblfault_tss.tss_fs = GSEL(GPRIV_SEL, SEL_KPL);
        dblfault_tss.tss_cs = GSEL(GCODE_SEL, SEL_KPL);
        dblfault_tss.tss_ldt = GSEL(GLDT_SEL, SEL_KPL);

        vm86_initialize();
        getmemsize(first);
        init_param2(physmem);

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

        /* Map the message buffer. */
        for (off = 0; off < round_page(MSGBUF_SIZE); off += PAGE_SIZE)
                pmap_kenter((vm_offset_t)msgbufp + off, avail_end + off);

        msgbufinit(msgbufp, MSGBUF_SIZE);

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

        x = (int) &IDTVEC(lcall_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 = x >> 16;

        /* XXX does this work? */
        ldt[LBSDICALLS_SEL] = ldt[LSYS5CALLS_SEL];
        ldt[LSOL26CALLS_SEL] = ldt[LSYS5CALLS_SEL];

        /* transfer to user mode */

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

        /* setup proc 0's pcb */
        thread0.td_pcb->pcb_flags = 0; /* XXXKSE */
        thread0.td_pcb->pcb_cr3 = (int)IdlePTD;
        thread0.td_pcb->pcb_ext = 0;
        thread0.td_frame = &proc0_tf;
}

void
cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t size)
{
}

#if defined(I586_CPU) && !defined(NO_F00F_HACK)
static void f00f_hack(void *unused);
SYSINIT(f00f_hack, SI_SUB_INTRINSIC, SI_ORDER_FIRST, f00f_hack, NULL);

static void
f00f_hack(void *unused) {
        struct gate_descriptor *new_idt;
#ifndef SMP
        struct region_descriptor r_idt;
#endif
        vm_offset_t tmp;

        if (!has_f00f_bug)
                return;

        GIANT_REQUIRED;

        printf("Intel Pentium detected, installing workaround for F00F bug\n");

        r_idt.rd_limit = sizeof(idt0) - 1;

        tmp = kmem_alloc(kernel_map, PAGE_SIZE * 2);
        if (tmp == 0)
                panic("kmem_alloc returned 0");
        if (((unsigned int)tmp & (PAGE_SIZE-1)) != 0)
                panic("kmem_alloc returned non-page-aligned memory");
        /* Put the first seven entries in the lower page */
        new_idt = (struct gate_descriptor*)(tmp + PAGE_SIZE - (7*8));
        bcopy(idt, new_idt, sizeof(idt0));
        r_idt.rd_base = (int)new_idt;
        lidt(&r_idt);
        idt = new_idt;
        if (vm_map_protect(kernel_map, tmp, tmp + PAGE_SIZE,
                           VM_PROT_READ, FALSE) != KERN_SUCCESS)
                panic("vm_map_protect failed");
        return;
}
#endif /* defined(I586_CPU) && !NO_F00F_HACK */

int
ptrace_set_pc(struct thread *td, unsigned long addr)
{
        td->td_frame->tf_eip = addr;
        return (0);
}

int
ptrace_single_step(struct thread *td)
{
        td->td_frame->tf_eflags |= PSL_T;
        return (0);
}

int
fill_regs(struct thread *td, struct reg *regs)
{
        struct pcb *pcb;
        struct trapframe *tp;

        tp = td->td_frame;
        regs->r_fs = tp->tf_fs;
        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;
        pcb = td->td_pcb;
        regs->r_gs = pcb->pcb_gs;
        return (0);
}

int
set_regs(struct thread *td, struct reg *regs)
{
        struct pcb *pcb;
        struct trapframe *tp;

        tp = td->td_frame;
        if (!EFL_SECURE(regs->r_eflags, tp->tf_eflags) ||
            !CS_SECURE(regs->r_cs))
                return (EINVAL);
        tp->tf_fs = regs->r_fs;
        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;
        pcb = td->td_pcb;
        pcb->pcb_gs = regs->r_gs;
        return (0);
}

#ifdef CPU_ENABLE_SSE
static void
fill_fpregs_xmm(sv_xmm, sv_87)
        struct savexmm *sv_xmm;
        struct save87 *sv_87;
{
        register struct env87 *penv_87 = &sv_87->sv_env;
        register struct envxmm *penv_xmm = &sv_xmm->sv_env;
        int i;

        bzero(sv_87, sizeof(*sv_87));

        /* FPU control/status */
        penv_87->en_cw = penv_xmm->en_cw;
        penv_87->en_sw = penv_xmm->en_sw;
        penv_87->en_tw = penv_xmm->en_tw;
        penv_87->en_fip = penv_xmm->en_fip;
        penv_87->en_fcs = penv_xmm->en_fcs;
        penv_87->en_opcode = penv_xmm->en_opcode;
        penv_87->en_foo = penv_xmm->en_foo;
        penv_87->en_fos = penv_xmm->en_fos;

        /* FPU registers */
        for (i = 0; i < 8; ++i)
                sv_87->sv_ac[i] = sv_xmm->sv_fp[i].fp_acc;
}

static void
set_fpregs_xmm(sv_87, sv_xmm)
        struct save87 *sv_87;
        struct savexmm *sv_xmm;
{
        register struct env87 *penv_87 = &sv_87->sv_env;
        register struct envxmm *penv_xmm = &sv_xmm->sv_env;
        int i;

        /* FPU control/status */
        penv_xmm->en_cw = penv_87->en_cw;
        penv_xmm->en_sw = penv_87->en_sw;
        penv_xmm->en_tw = penv_87->en_tw;
        penv_xmm->en_fip = penv_87->en_fip;
        penv_xmm->en_fcs = penv_87->en_fcs;
        penv_xmm->en_opcode = penv_87->en_opcode;
        penv_xmm->en_foo = penv_87->en_foo;
        penv_xmm->en_fos = penv_87->en_fos;

        /* FPU registers */
        for (i = 0; i < 8; ++i)
                sv_xmm->sv_fp[i].fp_acc = sv_87->sv_ac[i];
}
#endif /* CPU_ENABLE_SSE */

int
fill_fpregs(struct thread *td, struct fpreg *fpregs)
{
#ifdef CPU_ENABLE_SSE
        if (cpu_fxsr) {
                fill_fpregs_xmm(&td->td_pcb->pcb_save.sv_xmm,
                                                (struct save87 *)fpregs);
                return (0);
        }
#endif /* CPU_ENABLE_SSE */
        bcopy(&td->td_pcb->pcb_save.sv_87, fpregs, sizeof *fpregs);
        return (0);
}

int
set_fpregs(struct thread *td, struct fpreg *fpregs)
{
#ifdef CPU_ENABLE_SSE
        if (cpu_fxsr) {
                set_fpregs_xmm((struct save87 *)fpregs,
                                           &td->td_pcb->pcb_save.sv_xmm);
                return (0);
        }
#endif /* CPU_ENABLE_SSE */
        bcopy(fpregs, &td->td_pcb->pcb_save.sv_87, sizeof *fpregs);
        return (0);
}

/*
 * Get machine context.
 */
void
get_mcontext(struct thread *td, mcontext_t *mcp)
{
        struct trapframe *tp;

        tp = td->td_frame;

        mcp->mc_onstack = sigonstack(tp->tf_esp);
        mcp->mc_gs = td->td_pcb->pcb_gs;
        mcp->mc_fs = tp->tf_fs;
        mcp->mc_es = tp->tf_es;
        mcp->mc_ds = tp->tf_ds;
        mcp->mc_edi = tp->tf_edi;
        mcp->mc_esi = tp->tf_esi;
        mcp->mc_ebp = tp->tf_ebp;
        mcp->mc_isp = tp->tf_isp;
        mcp->mc_ebx = tp->tf_ebx;
        mcp->mc_edx = tp->tf_edx;
        mcp->mc_ecx = tp->tf_ecx;
        mcp->mc_eax = tp->tf_eax;
        mcp->mc_eip = tp->tf_eip;
        mcp->mc_cs = tp->tf_cs;
        mcp->mc_eflags = tp->tf_eflags;
        mcp->mc_esp = tp->tf_esp;
        mcp->mc_ss = tp->tf_ss;
        mcp->mc_len = sizeof(*mcp);
        get_fpcontext(td, mcp);
}

/*
 * Set machine context.
 *
 * However, we don't set any but the user modifiable flags, and we won't
 * touch the cs selector.
 */
int
set_mcontext(struct thread *td, const mcontext_t *mcp)
{
        struct trapframe *tp;
        int eflags, ret;

        tp = td->td_frame;
        if (mcp->mc_len != sizeof(*mcp))
                return (EINVAL);
        eflags = (mcp->mc_eflags & PSL_USERCHANGE) |
            (tp->tf_eflags & ~PSL_USERCHANGE);
        if ((ret = set_fpcontext(td, mcp)) == 0) {
                tp->tf_fs = mcp->mc_fs;
                tp->tf_es = mcp->mc_es;
                tp->tf_ds = mcp->mc_ds;
                tp->tf_edi = mcp->mc_edi;
                tp->tf_esi = mcp->mc_esi;
                tp->tf_ebp = mcp->mc_ebp;
                tp->tf_ebx = mcp->mc_ebx;
                tp->tf_edx = mcp->mc_edx;
                tp->tf_ecx = mcp->mc_ecx;
                tp->tf_eax = mcp->mc_eax;
                tp->tf_eip = mcp->mc_eip;
                tp->tf_eflags = eflags;
                tp->tf_esp = mcp->mc_esp;
                tp->tf_ss = mcp->mc_ss;
                td->td_pcb->pcb_gs = mcp->mc_gs;
                ret = 0;
        }
        return (ret);
}

static void
get_fpcontext(struct thread *td, mcontext_t *mcp)
{
#ifndef DEV_NPX
        mcp->mc_fpformat = _MC_FPFMT_NODEV;
        mcp->mc_ownedfp = _MC_FPOWNED_NONE;
#else /* DEV_NPX */
        union savefpu *addr;

        /*
         * XXX mc_fpstate might be misaligned, since its declaration is not
         * unportabilized using __attribute__((aligned(16))) like the
         * declaration of struct savemm, and anyway, alignment doesn't work
         * for auto variables since we don't use gcc's pessimal stack
         * alignment.  Work around this by abusing the spare fields after
         * mcp->mc_fpstate.
         *
         * XXX unpessimize most cases by only aligning when fxsave might be
         * called, although this requires knowing too much about
         * npxgetregs()'s internals.
         */
        addr = (union savefpu *)&mcp->mc_fpstate;
        if (td == PCPU_GET(fpcurthread) &&
#ifdef CPU_ENABLE_SSE
            cpu_fxsr &&
#endif
            ((uintptr_t)(void *)addr & 0xF)) {
                do
                        addr = (void *)((char *)addr + 4);
                while ((uintptr_t)(void *)addr & 0xF);
        }
        mcp->mc_ownedfp = npxgetregs(td, addr);
        if (addr != (union savefpu *)&mcp->mc_fpstate) {
                bcopy(addr, &mcp->mc_fpstate, sizeof(mcp->mc_fpstate));
                bzero(&mcp->mc_spare2, sizeof(mcp->mc_spare2));
        }
        bcopy(&mcp->mc_fpstate, &td->td_pcb->pcb_save, sizeof(mcp->mc_fpstate));
        mcp->mc_fpformat = npxformat();
#endif /* !DEV_NPX */
}

static int
set_fpcontext(struct thread *td, const mcontext_t *mcp)
{
        union savefpu *addr;

        if (mcp->mc_fpformat == _MC_FPFMT_NODEV)
                return (0);
        if (mcp->mc_ownedfp == _MC_FPOWNED_NONE)
                /* We don't care what state is left in the FPU or PCB. */
                fpstate_drop(td);
        else if (mcp->mc_ownedfp == _MC_FPOWNED_FPU ||
            mcp->mc_ownedfp == _MC_FPOWNED_PCB) {
                /* XXX align as above. */
                addr = (union savefpu *)&mcp->mc_fpstate;
                if (td == PCPU_GET(fpcurthread) &&
#ifdef CPU_ENABLE_SSE
                    cpu_fxsr &&
#endif
                    ((uintptr_t)(void *)addr & 0xF)) {
                        do
                                addr = (void *)((char *)addr + 4);
                        while ((uintptr_t)(void *)addr & 0xF);
                        bcopy(&mcp->mc_fpstate, addr, sizeof(mcp->mc_fpstate));
                }
#ifdef DEV_NPX
                /*
                 * XXX we violate the dubious requirement that npxsetregs()
                 * be called with interrupts disabled.
                 */
                npxsetregs(td, addr);
                /*
                 * Don't bother putting things back where they were in the
                 * misaligned case, since we know that the caller won't use
                 * them again.
                 */
        } else {
                /*
                 * There is no valid FPU state in *mcp, so use the saved
                 * state in the PCB if there is one.  XXX the test for
                 * whether there is one seems to be quite broken.  We
                 * forcibly drop the state in sendsig().
                 */
                if ((td->td_pcb->pcb_flags & PCB_NPXINITDONE) != 0)
                        npxsetregs(td, &td->td_pcb->pcb_save);
#endif
#if !defined(COMPAT_FREEBSD4) && !defined(COMPAT_43)
                return (EINVAL);
#endif
        }
        return (0);
}

static void
fpstate_drop(struct thread *td)
{
        register_t s;

        s = intr_disable();
#ifdef DEV_NPX
        if (PCPU_GET(fpcurthread) == td)
                npxdrop();
#endif
        /*
         * XXX force a full drop of the npx.  The above only drops it if we
         * owned it.  npxgetregs() has the same bug in the !cpu_fxsr case.
         *
         * XXX I don't much like npxgetregs()'s semantics of doing a full
         * drop.  Dropping only to the pcb matches fnsave's behaviour.
         * We only need to drop to !PCB_INITDONE in sendsig().  But
         * sendsig() is the only caller of npxgetregs()... perhaps we just
         * have too many layers.
         */
        curthread->td_pcb->pcb_flags &= ~PCB_NPXINITDONE;
        intr_restore(s);
}

int
fill_dbregs(struct thread *td, struct dbreg *dbregs)
{
        struct pcb *pcb;

        if (td == NULL) {
                dbregs->dr[0] = rdr0();
                dbregs->dr[1] = rdr1();
                dbregs->dr[2] = rdr2();
                dbregs->dr[3] = rdr3();
                dbregs->dr[4] = rdr4();
                dbregs->dr[5] = rdr5();
                dbregs->dr[6] = rdr6();
                dbregs->dr[7] = rdr7();
        } else {
                pcb = td->td_pcb;
                dbregs->dr[0] = pcb->pcb_dr0;
                dbregs->dr[1] = pcb->pcb_dr1;
                dbregs->dr[2] = pcb->pcb_dr2;
                dbregs->dr[3] = pcb->pcb_dr3;
                dbregs->dr[4] = 0;
                dbregs->dr[5] = 0;
                dbregs->dr[6] = pcb->pcb_dr6;
                dbregs->dr[7] = pcb->pcb_dr7;
        }
        return (0);
}

int
set_dbregs(struct thread *td, struct dbreg *dbregs)
{
        struct pcb *pcb;
        int i;
        u_int32_t mask1, mask2;

        if (td == NULL) {
                load_dr0(dbregs->dr[0]);
                load_dr1(dbregs->dr[1]);
                load_dr2(dbregs->dr[2]);
                load_dr3(dbregs->dr[3]);
                load_dr4(dbregs->dr[4]);
                load_dr5(dbregs->dr[5]);
                load_dr6(dbregs->dr[6]);
                load_dr7(dbregs->dr[7]);
        } else {
                /*
                 * Don't let an illegal value for dr7 get set.  Specifically,
                 * check for undefined settings.  Setting these bit patterns
                 * result in undefined behaviour and can lead to an unexpected
                 * TRCTRAP.
                 */
                for (i = 0, mask1 = 0x3<<16, mask2 = 0x2<<16; i < 8; 
                     i++, mask1 <<= 2, mask2 <<= 2)
                        if ((dbregs->dr[7] & mask1) == mask2)
                                return (EINVAL);
                
                pcb = td->td_pcb;
                
                /*
                 * Don't let a process set a breakpoint that is not within the
                 * process's address space.  If a process could do this, it
                 * could halt the system by setting a breakpoint in the kernel
                 * (if ddb was enabled).  Thus, we need to check to make sure
                 * that no breakpoints are being enabled for addresses outside
                 * process's address space, unless, perhaps, we were called by
                 * uid 0.
                 *
                 * XXX - what about when the watched area of the user's
                 * address space is written into from within the kernel
                 * ... wouldn't that still cause a breakpoint to be generated
                 * from within kernel mode?
                 */

                if (suser(td) != 0) {
                        if (dbregs->dr[7] & 0x3) {
                                /* dr0 is enabled */
                                if (dbregs->dr[0] >= VM_MAXUSER_ADDRESS)
                                        return (EINVAL);
                        }
                        
                        if (dbregs->dr[7] & (0x3<<2)) {
                                /* dr1 is enabled */
                                if (dbregs->dr[1] >= VM_MAXUSER_ADDRESS)
                                        return (EINVAL);
                        }
                        
                        if (dbregs->dr[7] & (0x3<<4)) {
                                /* dr2 is enabled */
                                if (dbregs->dr[2] >= VM_MAXUSER_ADDRESS)
                                        return (EINVAL);
                        }
                        
                        if (dbregs->dr[7] & (0x3<<6)) {
                                /* dr3 is enabled */
                                if (dbregs->dr[3] >= VM_MAXUSER_ADDRESS)
                                        return (EINVAL);
                        }
                }

                pcb->pcb_dr0 = dbregs->dr[0];
                pcb->pcb_dr1 = dbregs->dr[1];
                pcb->pcb_dr2 = dbregs->dr[2];
                pcb->pcb_dr3 = dbregs->dr[3];
                pcb->pcb_dr6 = dbregs->dr[6];
                pcb->pcb_dr7 = dbregs->dr[7];

                pcb->pcb_flags |= PCB_DBREGS;
        }

        return (0);
}

/*
 * Return > 0 if a hardware breakpoint has been hit, and the
 * breakpoint was in user space.  Return 0, otherwise.
 */
int
user_dbreg_trap(void)
{
        u_int32_t dr7, dr6; /* debug registers dr6 and dr7 */
        u_int32_t bp;       /* breakpoint bits extracted from dr6 */
        int nbp;            /* number of breakpoints that triggered */
        caddr_t addr[4];    /* breakpoint addresses */
        int i;
        
        dr7 = rdr7();
        if ((dr7 & 0x000000ff) == 0) {
                /*
                 * all GE and LE bits in the dr7 register are zero,
                 * thus the trap couldn't have been caused by the
                 * hardware debug registers
                 */
                return 0;
        }

        nbp = 0;
        dr6 = rdr6();
        bp = dr6 & 0x0000000f;

        if (!bp) {
                /*
                 * None of the breakpoint bits are set meaning this
                 * trap was not caused by any of the debug registers
                 */
                return 0;
        }

        /*
         * at least one of the breakpoints were hit, check to see
         * which ones and if any of them are user space addresses
         */

        if (bp & 0x01) {
                addr[nbp++] = (caddr_t)rdr0();
        }
        if (bp & 0x02) {
                addr[nbp++] = (caddr_t)rdr1();
        }
        if (bp & 0x04) {
                addr[nbp++] = (caddr_t)rdr2();
        }
        if (bp & 0x08) {
                addr[nbp++] = (caddr_t)rdr3();
        }

        for (i=0; i<nbp; i++) {
                if (addr[i] <
                    (caddr_t)VM_MAXUSER_ADDRESS) {
                        /*
                         * addr[i] is in user space
                         */
                        return nbp;
                }
        }

        /*
         * None of the breakpoints are in user space.
         */
        return 0;
}


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

#ifdef DDB

/*
 * Provide inb() and outb() as functions.  They are normally only
 * available as macros calling inlined functions, thus cannot be
 * called inside DDB.
 *
 * The actual code is stolen from <machine/cpufunc.h>, and de-inlined.
 */

#undef inb
#undef outb

/* silence compiler warnings */
u_char inb(u_int);
void outb(u_int, u_char);

u_char
inb(u_int port)
{
        u_char  data;
        /*
         * We use %%dx and not %1 here because i/o is done at %dx and not at
         * %edx, while gcc generates inferior code (movw instead of movl)
         * if we tell it to load (u_short) port.
         */
        __asm __volatile("inb %%dx,%0" : "=a" (data) : "d" (port));
        return (data);
}

void
outb(u_int port, u_char data)
{
        u_char  al;
        /*
         * Use an unnecessary assignment to help gcc's register allocator.
         * This make a large difference for gcc-1.40 and a tiny difference
         * for gcc-2.6.0.  For gcc-1.40, al had to be ``asm("ax")'' for
         * best results.  gcc-2.6.0 can't handle this.
         */
        al = data;
        __asm __volatile("outb %0,%%dx" : : "a" (al), "d" (port));
}

#endif /* DDB */