/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright (c) 2003 Peter Wemm.
 * 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.
 */

#include <sys/cdefs.h>
#include "opt_cpu.h"
#include "opt_ddb.h"
#include "opt_kstack_pages.h"

#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/exec.h>
#include <sys/imgact.h>
#include <sys/kdb.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/reg.h>
#include <sys/rwlock.h>
#include <sys/signalvar.h>
#include <sys/smp.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/ucontext.h>
#include <sys/vmmeter.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>

#ifdef DDB
#ifndef KDB
#error KDB must be enabled in order for DDB to work!
#endif
#include <ddb/ddb.h>
#include <ddb/db_sym.h>
#endif

#include <machine/vmparam.h>
#include <machine/frame.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/proc.h>
#include <machine/sigframe.h>
#include <machine/specialreg.h>
#include <machine/trap.h>

_Static_assert(sizeof(mcontext_t) == 800, "mcontext_t size incorrect");
_Static_assert(sizeof(ucontext_t) == 880, "ucontext_t size incorrect");
_Static_assert(sizeof(siginfo_t) == 80, "siginfo_t size incorrect");

/*
 * Check that the value r is 16bit, i.e. fits into a segment register.
 */
static bool
is_seg_val(register_t r)
{
        return ((uint64_t)r <= 0xffff);
}

/*
 * Send an interrupt to process.
 *
 * Stack is set up to allow sigcode stored at top to call routine,
 * followed by call 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(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
{
        struct sigframe sf, *sfp;
        struct pcb *pcb;
        struct proc *p;
        struct thread *td;
        struct sigacts *psp;
        char *sp;
        struct trapframe *regs;
        char *xfpusave;
        size_t xfpusave_len;
        int sig;
        int oonstack;

        td = curthread;
        pcb = td->td_pcb;
        p = td->td_proc;
        PROC_LOCK_ASSERT(p, MA_OWNED);
        sig = ksi->ksi_signo;
        psp = p->p_sigacts;
        mtx_assert(&psp->ps_mtx, MA_OWNED);
        regs = td->td_frame;
        oonstack = sigonstack(regs->tf_rsp);

        /* Save user context. */
        bzero(&sf, sizeof(sf));
        sf.sf_uc.uc_sigmask = *mask;
        sf.sf_uc.uc_stack = td->td_sigstk;
        sf.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
            ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE;
        sf.sf_uc.uc_mcontext.mc_onstack = (oonstack) ? 1 : 0;
        sf.sf_uc.uc_mcontext.mc_rdi = regs->tf_rdi;
        sf.sf_uc.uc_mcontext.mc_rsi = regs->tf_rsi;
        sf.sf_uc.uc_mcontext.mc_rdx = regs->tf_rdx;
        sf.sf_uc.uc_mcontext.mc_rcx = regs->tf_rcx;
        sf.sf_uc.uc_mcontext.mc_r8 = regs->tf_r8;
        sf.sf_uc.uc_mcontext.mc_r9 = regs->tf_r9;
        sf.sf_uc.uc_mcontext.mc_rax = regs->tf_rax;
        sf.sf_uc.uc_mcontext.mc_rbx = regs->tf_rbx;
        sf.sf_uc.uc_mcontext.mc_rbp = regs->tf_rbp;
        sf.sf_uc.uc_mcontext.mc_r10 = regs->tf_r10;
        sf.sf_uc.uc_mcontext.mc_r11 = regs->tf_r11;
        sf.sf_uc.uc_mcontext.mc_r12 = regs->tf_r12;
        sf.sf_uc.uc_mcontext.mc_r13 = regs->tf_r13;
        sf.sf_uc.uc_mcontext.mc_r14 = regs->tf_r14;
        sf.sf_uc.uc_mcontext.mc_r15 = regs->tf_r15;
        sf.sf_uc.uc_mcontext.mc_trapno = regs->tf_trapno;
        sf.sf_uc.uc_mcontext.mc_fs = regs->tf_fs;
        sf.sf_uc.uc_mcontext.mc_gs = regs->tf_gs;
        sf.sf_uc.uc_mcontext.mc_addr = regs->tf_addr;
        sf.sf_uc.uc_mcontext.mc_flags = regs->tf_flags;
        sf.sf_uc.uc_mcontext.mc_es = regs->tf_es;
        sf.sf_uc.uc_mcontext.mc_ds = regs->tf_ds;
        sf.sf_uc.uc_mcontext.mc_err = regs->tf_err;
        sf.sf_uc.uc_mcontext.mc_rip = regs->tf_rip;
        sf.sf_uc.uc_mcontext.mc_cs = regs->tf_cs;
        sf.sf_uc.uc_mcontext.mc_rflags = regs->tf_rflags;
        sf.sf_uc.uc_mcontext.mc_rsp = regs->tf_rsp;
        sf.sf_uc.uc_mcontext.mc_ss = regs->tf_ss;
        sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext); /* magic */
        get_fpcontext(td, &sf.sf_uc.uc_mcontext, &xfpusave, &xfpusave_len);
        update_pcb_bases(pcb);
        sf.sf_uc.uc_mcontext.mc_fsbase = pcb->pcb_fsbase;
        sf.sf_uc.uc_mcontext.mc_gsbase = pcb->pcb_gsbase;
        bzero(sf.sf_uc.uc_mcontext.mc_spare,
            sizeof(sf.sf_uc.uc_mcontext.mc_spare));

        /* Allocate space for the signal handler context. */
        if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack &&
            SIGISMEMBER(psp->ps_sigonstack, sig)) {
                sp = (char *)td->td_sigstk.ss_sp + td->td_sigstk.ss_size;
#if defined(COMPAT_43)
                td->td_sigstk.ss_flags |= SS_ONSTACK;
#endif
        } else
                sp = (char *)regs->tf_rsp - REDZONE_SZ;
        if (xfpusave != NULL) {
                sp -= xfpusave_len;
                sp = (char *)((unsigned long)sp & ~0x3Ful);
                sf.sf_uc.uc_mcontext.mc_xfpustate = (register_t)sp;
        }
        sp -= sizeof(struct sigframe);
        /* Align to 16 bytes. */
        sfp = (struct sigframe *)STACKALIGN(sp);

        /* Build the argument list for the signal handler. */
        regs->tf_rdi = sig;                     /* arg 1 in %rdi */
        regs->tf_rdx = (register_t)&sfp->sf_uc; /* arg 3 in %rdx */
        bzero(&sf.sf_si, sizeof(sf.sf_si));
        if (SIGISMEMBER(psp->ps_siginfo, sig)) {
                /* Signal handler installed with SA_SIGINFO. */
                regs->tf_rsi = (register_t)&sfp->sf_si; /* arg 2 in %rsi */
                sf.sf_ahu.sf_action = (__siginfohandler_t *)catcher;

                /* Fill in POSIX parts */
                sf.sf_si = ksi->ksi_info;
                sf.sf_si.si_signo = sig; /* maybe a translated signal */
                regs->tf_rcx = (register_t)ksi->ksi_addr; /* arg 4 in %rcx */
        } else {
                /* Old FreeBSD-style arguments. */
                regs->tf_rsi = ksi->ksi_code;   /* arg 2 in %rsi */
                regs->tf_rcx = (register_t)ksi->ksi_addr; /* arg 4 in %rcx */
                sf.sf_ahu.sf_handler = catcher;
        }
        mtx_unlock(&psp->ps_mtx);
        PROC_UNLOCK(p);

        /*
         * Copy the sigframe out to the user's stack.
         */
        if (copyout(&sf, sfp, sizeof(*sfp)) != 0 ||
            (xfpusave != NULL && copyout(xfpusave,
            (void *)sf.sf_uc.uc_mcontext.mc_xfpustate, xfpusave_len)
            != 0)) {
                uprintf("pid %d comm %s has trashed its stack, killing\n",
                    p->p_pid, p->p_comm);
                PROC_LOCK(p);
                sigexit(td, SIGILL);
        }

        fpstate_drop(td);
        regs->tf_rsp = (long)sfp;
        regs->tf_rip = PROC_SIGCODE(p);
        regs->tf_rflags &= ~(PSL_T | PSL_D);
        regs->tf_cs = _ucodesel;
        regs->tf_ds = _udatasel;
        regs->tf_ss = _udatasel;
        regs->tf_es = _udatasel;
        regs->tf_fs = _ufssel;
        regs->tf_gs = _ugssel;
        regs->tf_flags = TF_HASSEGS;
        if ((pcb->pcb_flags & PCB_TLSBASE) != 0)
                pcb->pcb_fsbase = pcb->pcb_tlsbase;
        PROC_LOCK(p);
        mtx_lock(&psp->ps_mtx);
}

/*
 * 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.
 */
int
sys_sigreturn(struct thread *td, struct sigreturn_args *uap)
{
        ucontext_t uc;
        struct pcb *pcb;
        struct proc *p;
        struct trapframe *regs;
        ucontext_t *ucp;
        char *xfpustate;
        size_t xfpustate_len;
        long rflags;
        int cs, error, ret;
        ksiginfo_t ksi;

        pcb = td->td_pcb;
        p = td->td_proc;

        error = copyin(uap->sigcntxp, &uc, sizeof(uc));
        if (error != 0) {
                uprintf("pid %d (%s): sigreturn copyin failed\n",
                    p->p_pid, td->td_name);
                return (error);
        }
        ucp = &uc;
        if ((ucp->uc_mcontext.mc_flags & ~_MC_FLAG_MASK) != 0) {
                uprintf("pid %d (%s): sigreturn mc_flags %x\n", p->p_pid,
                    td->td_name, ucp->uc_mcontext.mc_flags);
                return (EINVAL);
        }
        regs = td->td_frame;
        rflags = ucp->uc_mcontext.mc_rflags;
        /*
         * Don't allow users to change privileged or reserved flags.
         */
        if (!EFL_SECURE(rflags, regs->tf_rflags)) {
                uprintf("pid %d (%s): sigreturn rflags = 0x%lx\n", p->p_pid,
                    td->td_name, rflags);
                return (EINVAL);
        }

        if (!is_seg_val(ucp->uc_mcontext.mc_ss) ||
            !is_seg_val(ucp->uc_mcontext.mc_cs)) {
                uprintf("pid %d (%s): sigreturn cs = %#lx ss = %#lx\n",
                    p->p_pid, td->td_name, ucp->uc_mcontext.mc_cs,
                    ucp->uc_mcontext.mc_ss);
                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)) {
                uprintf("pid %d (%s): sigreturn cs = 0x%x\n", p->p_pid,
                    td->td_name, cs);
                ksiginfo_init_trap(&ksi);
                ksi.ksi_signo = SIGBUS;
                ksi.ksi_code = BUS_OBJERR;
                ksi.ksi_trapno = T_PROTFLT;
                ksi.ksi_addr = (void *)regs->tf_rip;
                trapsignal(td, &ksi);
                return (EINVAL);
        }

        if ((uc.uc_mcontext.mc_flags & _MC_HASFPXSTATE) != 0) {
                xfpustate_len = uc.uc_mcontext.mc_xfpustate_len;
                if (xfpustate_len > cpu_max_ext_state_size -
                    sizeof(struct savefpu)) {
                        uprintf("pid %d (%s): sigreturn xfpusave_len = 0x%zx\n",
                            p->p_pid, td->td_name, xfpustate_len);
                        return (EINVAL);
                }
                xfpustate = (char *)fpu_save_area_alloc();
                error = copyin((const void *)uc.uc_mcontext.mc_xfpustate,
                    xfpustate, xfpustate_len);
                if (error != 0) {
                        fpu_save_area_free((struct savefpu *)xfpustate);
                        uprintf(
        "pid %d (%s): sigreturn copying xfpustate failed\n",
                            p->p_pid, td->td_name);
                        return (error);
                }
        } else {
                xfpustate = NULL;
                xfpustate_len = 0;
        }
        ret = set_fpcontext(td, &ucp->uc_mcontext, xfpustate, xfpustate_len);
        fpu_save_area_free((struct savefpu *)xfpustate);
        if (ret != 0) {
                uprintf("pid %d (%s): sigreturn set_fpcontext err %d\n",
                    p->p_pid, td->td_name, ret);
                return (ret);
        }
        bcopy(&ucp->uc_mcontext.mc_rdi, regs, sizeof(*regs));
        update_pcb_bases(pcb);
        pcb->pcb_fsbase = ucp->uc_mcontext.mc_fsbase;
        pcb->pcb_gsbase = ucp->uc_mcontext.mc_gsbase;

#if defined(COMPAT_43)
        if (ucp->uc_mcontext.mc_onstack & 1)
                td->td_sigstk.ss_flags |= SS_ONSTACK;
        else
                td->td_sigstk.ss_flags &= ~SS_ONSTACK;
#endif

        kern_sigprocmask(td, SIG_SETMASK, &ucp->uc_sigmask, NULL, 0);
        return (EJUSTRETURN);
}

#ifdef COMPAT_FREEBSD4
int
freebsd4_sigreturn(struct thread *td, struct freebsd4_sigreturn_args *uap)
{

        return sys_sigreturn(td, (struct sigreturn_args *)uap);
}
#endif

/*
 * Reset the hardware debug registers if they were in use.
 * They won't have any meaning for the newly exec'd process.
 */
void
x86_clear_dbregs(struct pcb *pcb)
{
        if ((pcb->pcb_flags & PCB_DBREGS) == 0)
                return;

        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 == curpcb) {
                /*
                 * Clear the debug registers on the running CPU,
                 * otherwise they will end up affecting the next
                 * process we switch to.
                 */
                reset_dbregs();
        }
        clear_pcb_flags(pcb, PCB_DBREGS);
}

/*
 * Reset registers to default values on exec.
 */
void
exec_setregs(struct thread *td, struct image_params *imgp, uintptr_t stack)
{
        struct trapframe *regs;
        struct pcb *pcb;
        register_t saved_rflags;

        regs = td->td_frame;
        pcb = td->td_pcb;

        if (td->td_proc->p_md.md_ldt != NULL)
                user_ldt_free(td);

        update_pcb_bases(pcb);
        pcb->pcb_fsbase = pcb->pcb_tlsbase = 0;
        pcb->pcb_gsbase = 0;
        clear_pcb_flags(pcb, PCB_32BIT | PCB_TLSBASE);
        pcb->pcb_initial_fpucw = __INITIAL_FPUCW__;

        saved_rflags = regs->tf_rflags & PSL_T;
        bzero((char *)regs, sizeof(struct trapframe));
        regs->tf_rip = imgp->entry_addr;
        regs->tf_rsp = ((stack - 8) & ~0xFul) + 8;
        regs->tf_rdi = stack;           /* argv */
        regs->tf_rflags = PSL_USER | saved_rflags;
        regs->tf_ss = _udatasel;
        regs->tf_cs = _ucodesel;
        regs->tf_ds = _udatasel;
        regs->tf_es = _udatasel;
        regs->tf_fs = _ufssel;
        regs->tf_gs = _ugssel;
        regs->tf_flags = TF_HASSEGS;

        x86_clear_dbregs(pcb);

        /*
         * Drop the FP state if we hold it, so that the process gets a
         * clean FP state if it uses the FPU again.
         */
        fpstate_drop(td);
}

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

        tp = td->td_frame;
        return (fill_frame_regs(tp, regs));
}

int
fill_frame_regs(struct trapframe *tp, struct reg *regs)
{

        regs->r_r15 = tp->tf_r15;
        regs->r_r14 = tp->tf_r14;
        regs->r_r13 = tp->tf_r13;
        regs->r_r12 = tp->tf_r12;
        regs->r_r11 = tp->tf_r11;
        regs->r_r10 = tp->tf_r10;
        regs->r_r9  = tp->tf_r9;
        regs->r_r8  = tp->tf_r8;
        regs->r_rdi = tp->tf_rdi;
        regs->r_rsi = tp->tf_rsi;
        regs->r_rbp = tp->tf_rbp;
        regs->r_rbx = tp->tf_rbx;
        regs->r_rdx = tp->tf_rdx;
        regs->r_rcx = tp->tf_rcx;
        regs->r_rax = tp->tf_rax;
        regs->r_rip = tp->tf_rip;
        regs->r_cs = tp->tf_cs;
        regs->r_rflags = tp->tf_rflags;
        regs->r_rsp = tp->tf_rsp;
        regs->r_ss = tp->tf_ss;
        if (tp->tf_flags & TF_HASSEGS) {
                regs->r_ds = tp->tf_ds;
                regs->r_es = tp->tf_es;
                regs->r_fs = tp->tf_fs;
                regs->r_gs = tp->tf_gs;
        } else {
                regs->r_ds = 0;
                regs->r_es = 0;
                regs->r_fs = 0;
                regs->r_gs = 0;
        }
        regs->r_err = 0;
        regs->r_trapno = 0;
        return (0);
}

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

        tp = td->td_frame;
        rflags = regs->r_rflags & 0xffffffff;
        if (!EFL_SECURE(rflags, tp->tf_rflags) || !CS_SECURE(regs->r_cs))
                return (EINVAL);
        tp->tf_r15 = regs->r_r15;
        tp->tf_r14 = regs->r_r14;
        tp->tf_r13 = regs->r_r13;
        tp->tf_r12 = regs->r_r12;
        tp->tf_r11 = regs->r_r11;
        tp->tf_r10 = regs->r_r10;
        tp->tf_r9  = regs->r_r9;
        tp->tf_r8  = regs->r_r8;
        tp->tf_rdi = regs->r_rdi;
        tp->tf_rsi = regs->r_rsi;
        tp->tf_rbp = regs->r_rbp;
        tp->tf_rbx = regs->r_rbx;
        tp->tf_rdx = regs->r_rdx;
        tp->tf_rcx = regs->r_rcx;
        tp->tf_rax = regs->r_rax;
        tp->tf_rip = regs->r_rip;
        tp->tf_cs = regs->r_cs;
        tp->tf_rflags = rflags;
        tp->tf_rsp = regs->r_rsp;
        tp->tf_ss = regs->r_ss;
        if (0) {        /* XXXKIB */
                tp->tf_ds = regs->r_ds;
                tp->tf_es = regs->r_es;
                tp->tf_fs = regs->r_fs;
                tp->tf_gs = regs->r_gs;
                tp->tf_flags = TF_HASSEGS;
        }
        set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
        return (0);
}

/* XXX check all this stuff! */
/* externalize from sv_xmm */
static void
fill_fpregs_xmm(struct savefpu *sv_xmm, struct fpreg *fpregs)
{
        struct envxmm *penv_fpreg = (struct envxmm *)&fpregs->fpr_env;
        struct envxmm *penv_xmm = &sv_xmm->sv_env;
        int i;

        /* pcb -> fpregs */
        bzero(fpregs, sizeof(*fpregs));

        /* FPU control/status */
        penv_fpreg->en_cw = penv_xmm->en_cw;
        penv_fpreg->en_sw = penv_xmm->en_sw;
        penv_fpreg->en_tw = penv_xmm->en_tw;
        penv_fpreg->en_opcode = penv_xmm->en_opcode;
        penv_fpreg->en_rip = penv_xmm->en_rip;
        penv_fpreg->en_rdp = penv_xmm->en_rdp;
        penv_fpreg->en_mxcsr = penv_xmm->en_mxcsr;
        penv_fpreg->en_mxcsr_mask = penv_xmm->en_mxcsr_mask;

        /* FPU registers */
        for (i = 0; i < 8; ++i)
                bcopy(sv_xmm->sv_fp[i].fp_acc.fp_bytes, fpregs->fpr_acc[i], 10);

        /* SSE registers */
        for (i = 0; i < 16; ++i)
                bcopy(sv_xmm->sv_xmm[i].xmm_bytes, fpregs->fpr_xacc[i], 16);
}

/* internalize from fpregs into sv_xmm */
static void
set_fpregs_xmm(struct fpreg *fpregs, struct savefpu *sv_xmm)
{
        struct envxmm *penv_xmm = &sv_xmm->sv_env;
        struct envxmm *penv_fpreg = (struct envxmm *)&fpregs->fpr_env;
        int i;

        /* fpregs -> pcb */
        /* FPU control/status */
        penv_xmm->en_cw = penv_fpreg->en_cw;
        penv_xmm->en_sw = penv_fpreg->en_sw;
        penv_xmm->en_tw = penv_fpreg->en_tw;
        penv_xmm->en_opcode = penv_fpreg->en_opcode;
        penv_xmm->en_rip = penv_fpreg->en_rip;
        penv_xmm->en_rdp = penv_fpreg->en_rdp;
        penv_xmm->en_mxcsr = penv_fpreg->en_mxcsr;
        penv_xmm->en_mxcsr_mask = penv_fpreg->en_mxcsr_mask & cpu_mxcsr_mask;

        /* FPU registers */
        for (i = 0; i < 8; ++i)
                bcopy(fpregs->fpr_acc[i], sv_xmm->sv_fp[i].fp_acc.fp_bytes, 10);

        /* SSE registers */
        for (i = 0; i < 16; ++i)
                bcopy(fpregs->fpr_xacc[i], sv_xmm->sv_xmm[i].xmm_bytes, 16);
}

/* externalize from td->pcb */
int
fill_fpregs(struct thread *td, struct fpreg *fpregs)
{

        KASSERT(td == curthread || TD_IS_SUSPENDED(td) ||
            P_SHOULDSTOP(td->td_proc),
            ("not suspended thread %p", td));
        fpugetregs(td);
        fill_fpregs_xmm(get_pcb_user_save_td(td), fpregs);
        return (0);
}

/* internalize to td->pcb */
int
set_fpregs(struct thread *td, struct fpreg *fpregs)
{

        critical_enter();
        set_fpregs_xmm(fpregs, get_pcb_user_save_td(td));
        fpuuserinited(td);
        critical_exit();
        return (0);
}

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

        pcb = td->td_pcb;
        tp = td->td_frame;
        PROC_LOCK(curthread->td_proc);
        mcp->mc_onstack = sigonstack(tp->tf_rsp);
        PROC_UNLOCK(curthread->td_proc);
        mcp->mc_r15 = tp->tf_r15;
        mcp->mc_r14 = tp->tf_r14;
        mcp->mc_r13 = tp->tf_r13;
        mcp->mc_r12 = tp->tf_r12;
        mcp->mc_r11 = tp->tf_r11;
        mcp->mc_r10 = tp->tf_r10;
        mcp->mc_r9  = tp->tf_r9;
        mcp->mc_r8  = tp->tf_r8;
        mcp->mc_rdi = tp->tf_rdi;
        mcp->mc_rsi = tp->tf_rsi;
        mcp->mc_rbp = tp->tf_rbp;
        mcp->mc_rbx = tp->tf_rbx;
        mcp->mc_rcx = tp->tf_rcx;
        mcp->mc_rflags = tp->tf_rflags;
        if (flags & GET_MC_CLEAR_RET) {
                mcp->mc_rax = 0;
                mcp->mc_rdx = 0;
                mcp->mc_rflags &= ~PSL_C;
        } else {
                mcp->mc_rax = tp->tf_rax;
                mcp->mc_rdx = tp->tf_rdx;
        }
        mcp->mc_rip = tp->tf_rip;
        mcp->mc_cs = tp->tf_cs;
        mcp->mc_rsp = tp->tf_rsp;
        mcp->mc_ss = tp->tf_ss;
        mcp->mc_ds = tp->tf_ds;
        mcp->mc_es = tp->tf_es;
        mcp->mc_fs = tp->tf_fs;
        mcp->mc_gs = tp->tf_gs;
        mcp->mc_flags = tp->tf_flags;
        mcp->mc_len = sizeof(*mcp);
        get_fpcontext(td, mcp, NULL, NULL);
        update_pcb_bases(pcb);
        mcp->mc_fsbase = pcb->pcb_fsbase;
        mcp->mc_gsbase = pcb->pcb_gsbase;
        mcp->mc_xfpustate = 0;
        mcp->mc_xfpustate_len = 0;
        mcp->mc_tlsbase = (pcb->pcb_flags & PCB_TLSBASE) != 0 ?
            pcb->pcb_tlsbase : 0;
        bzero(mcp->mc_spare, sizeof(mcp->mc_spare));
        return (0);
}

/*
 * 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, mcontext_t *mcp)
{
        struct pcb *pcb;
        struct trapframe *tp;
        char *xfpustate;
        long rflags;
        int ret;

        pcb = td->td_pcb;
        tp = td->td_frame;
        if (mcp->mc_len != sizeof(*mcp) ||
            (mcp->mc_flags & ~_MC_FLAG_MASK) != 0)
                return (EINVAL);
        if (!is_seg_val(mcp->mc_ss) || !is_seg_val(mcp->mc_cs))
                return (EINVAL);
        rflags = (mcp->mc_rflags & PSL_USERCHANGE) |
            (tp->tf_rflags & ~PSL_USERCHANGE);
        if (mcp->mc_flags & _MC_HASFPXSTATE) {
                if (mcp->mc_xfpustate_len > cpu_max_ext_state_size -
                    sizeof(struct savefpu))
                        return (EINVAL);
                xfpustate = (char *)fpu_save_area_alloc();
                ret = copyin((void *)mcp->mc_xfpustate, xfpustate,
                    mcp->mc_xfpustate_len);
                if (ret != 0) {
                        fpu_save_area_free((struct savefpu *)xfpustate);
                        return (ret);
                }
        } else
                xfpustate = NULL;
        ret = set_fpcontext(td, mcp, xfpustate, mcp->mc_xfpustate_len);
        fpu_save_area_free((struct savefpu *)xfpustate);
        if (ret != 0)
                return (ret);
        tp->tf_r15 = mcp->mc_r15;
        tp->tf_r14 = mcp->mc_r14;
        tp->tf_r13 = mcp->mc_r13;
        tp->tf_r12 = mcp->mc_r12;
        tp->tf_r11 = mcp->mc_r11;
        tp->tf_r10 = mcp->mc_r10;
        tp->tf_r9  = mcp->mc_r9;
        tp->tf_r8  = mcp->mc_r8;
        tp->tf_rdi = mcp->mc_rdi;
        tp->tf_rsi = mcp->mc_rsi;
        tp->tf_rbp = mcp->mc_rbp;
        tp->tf_rbx = mcp->mc_rbx;
        tp->tf_rdx = mcp->mc_rdx;
        tp->tf_rcx = mcp->mc_rcx;
        tp->tf_rax = mcp->mc_rax;
        tp->tf_rip = mcp->mc_rip;
        tp->tf_rflags = rflags;
        tp->tf_rsp = mcp->mc_rsp;
        tp->tf_ss = mcp->mc_ss;
        tp->tf_flags = mcp->mc_flags;
        if (tp->tf_flags & TF_HASSEGS) {
                tp->tf_ds = mcp->mc_ds;
                tp->tf_es = mcp->mc_es;
                tp->tf_fs = mcp->mc_fs;
                tp->tf_gs = mcp->mc_gs;
        }
        set_pcb_flags(pcb, PCB_FULL_IRET);
        if (mcp->mc_flags & _MC_HASBASES) {
                pcb->pcb_fsbase = mcp->mc_fsbase;
                pcb->pcb_gsbase = mcp->mc_gsbase;
        }
        if ((mcp->mc_flags & _MC_HASTLSBASE) != 0) {
                pcb->pcb_tlsbase = mcp->mc_tlsbase;
                set_pcb_flags(pcb, PCB_TLSBASE);
        }
        return (0);
}

void
get_fpcontext(struct thread *td, mcontext_t *mcp, char **xfpusave,
    size_t *xfpusave_len)
{
        mcp->mc_ownedfp = fpugetregs(td);
        bcopy(get_pcb_user_save_td(td), &mcp->mc_fpstate[0],
            sizeof(mcp->mc_fpstate));
        mcp->mc_fpformat = fpuformat();
        if (xfpusave == NULL)
                return;
        if (!use_xsave || cpu_max_ext_state_size <= sizeof(struct savefpu)) {
                *xfpusave_len = 0;
                *xfpusave = NULL;
        } else {
                mcp->mc_flags |= _MC_HASFPXSTATE;
                *xfpusave_len = mcp->mc_xfpustate_len =
                    cpu_max_ext_state_size - sizeof(struct savefpu);
                *xfpusave = (char *)(get_pcb_user_save_td(td) + 1);
        }
}

int
set_fpcontext(struct thread *td, mcontext_t *mcp, char *xfpustate,
    size_t xfpustate_len)
{
        int error;

        if (mcp->mc_fpformat == _MC_FPFMT_NODEV)
                return (0);
        else if (mcp->mc_fpformat != _MC_FPFMT_XMM)
                return (EINVAL);
        else if (mcp->mc_ownedfp == _MC_FPOWNED_NONE) {
                /* We don't care what state is left in the FPU or PCB. */
                fpstate_drop(td);
                error = 0;
        } else if (mcp->mc_ownedfp == _MC_FPOWNED_FPU ||
            mcp->mc_ownedfp == _MC_FPOWNED_PCB) {
                error = fpusetregs(td, (struct savefpu *)&mcp->mc_fpstate,
                    xfpustate, xfpustate_len);
        } else
                return (EINVAL);
        return (error);
}

void
fpstate_drop(struct thread *td)
{

        KASSERT(PCB_USER_FPU(td->td_pcb), ("fpstate_drop: kernel-owned fpu"));
        critical_enter();
        if (PCPU_GET(fpcurthread) == td)
                fpudrop();
        /*
         * XXX force a full drop of the fpu.  The above only drops it if we
         * owned it.
         *
         * XXX I don't much like fpugetuserregs()'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 fpugetuserregs()... perhaps we just
         * have too many layers.
         */
        clear_pcb_flags(curthread->td_pcb,
            PCB_FPUINITDONE | PCB_USERFPUINITDONE);
        critical_exit();
}

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[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[6] = pcb->pcb_dr6;
                dbregs->dr[7] = pcb->pcb_dr7;
        }
        dbregs->dr[4] = 0;
        dbregs->dr[5] = 0;
        dbregs->dr[8] = 0;
        dbregs->dr[9] = 0;
        dbregs->dr[10] = 0;
        dbregs->dr[11] = 0;
        dbregs->dr[12] = 0;
        dbregs->dr[13] = 0;
        dbregs->dr[14] = 0;
        dbregs->dr[15] = 0;
        return (0);
}

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

        if (td == NULL) {
                load_dr0(dbregs->dr[0]);
                load_dr1(dbregs->dr[1]);
                load_dr2(dbregs->dr[2]);
                load_dr3(dbregs->dr[3]);
                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 or a general protection fault right here.
                 * Upper bits of dr6 and dr7 must not be set
                 */
                for (i = 0; i < 4; i++) {
                        if (DBREG_DR7_ACCESS(dbregs->dr[7], i) == 0x02)
                                return (EINVAL);
                        if (td->td_frame->tf_cs == _ucode32sel &&
                            DBREG_DR7_LEN(dbregs->dr[7], i) == DBREG_DR7_LEN_8)
                                return (EINVAL);
                }
                if ((dbregs->dr[6] & 0xffffffff00000000ul) != 0 ||
                    (dbregs->dr[7] & 0xffffffff00000000ul) != 0)
                        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.
                 *
                 * 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 (DBREG_DR7_ENABLED(dbregs->dr[7], 0)) {
                        /* dr0 is enabled */
                        if (dbregs->dr[0] >= VM_MAXUSER_ADDRESS)
                                return (EINVAL);
                }
                if (DBREG_DR7_ENABLED(dbregs->dr[7], 1)) {
                        /* dr1 is enabled */
                        if (dbregs->dr[1] >= VM_MAXUSER_ADDRESS)
                                return (EINVAL);
                }
                if (DBREG_DR7_ENABLED(dbregs->dr[7], 2)) {
                        /* dr2 is enabled */
                        if (dbregs->dr[2] >= VM_MAXUSER_ADDRESS)
                                return (EINVAL);
                }
                if (DBREG_DR7_ENABLED(dbregs->dr[7], 3)) {
                        /* 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];

                set_pcb_flags(pcb, PCB_DBREGS);
        }

        return (0);
}

void
reset_dbregs(void)
{

        load_dr7(0);    /* Turn off the control bits first */
        load_dr0(0);
        load_dr1(0);
        load_dr2(0);
        load_dr3(0);
        load_dr6(0);
}

/*
 * Return > 0 if a hardware breakpoint has been hit, and the
 * breakpoint was in user space.  Return 0, otherwise.
 */
int
user_dbreg_trap(register_t dr6)
{
        u_int64_t dr7;
        u_int64_t bp;       /* breakpoint bits extracted from dr6 */
        int nbp;            /* number of breakpoints that triggered */
        caddr_t addr[4];    /* breakpoint addresses */
        int i;

        bp = dr6 & DBREG_DR6_BMASK;
        if (bp == 0) {
                /*
                 * None of the breakpoint bits are set meaning this
                 * trap was not caused by any of the debug registers
                 */
                return (0);
        }

        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;

        /*
         * 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);
}