1 /*-
2  * Copyright (c) 1992 Terrence R. Lambert.
3  * Copyright (C) 1994, David Greenman
4  * Copyright (c) 1982, 1987, 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * William Jolitz.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	from: @(#)machdep.c	7.4 (Berkeley) 6/3/91
39  * $FreeBSD: src/sys/i386/i386/machdep.c,v 1.385.2.30 2003/05/31 08:48:05 alc Exp $
40  */
41 
42 #include "opt_ddb.h"
43 #include "opt_inet.h"
44 #include "opt_msgbuf.h"
45 #include "opt_swap.h"
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/sysproto.h>
50 #include <sys/signalvar.h>
51 #include <sys/kernel.h>
52 #include <sys/linker.h>
53 #include <sys/malloc.h>
54 #include <sys/proc.h>
55 #include <sys/buf.h>
56 #include <sys/reboot.h>
57 #include <sys/mbuf.h>
58 #include <sys/msgbuf.h>
59 #include <sys/sysent.h>
60 #include <sys/sysctl.h>
61 #include <sys/vmmeter.h>
62 #include <sys/bus.h>
63 #include <sys/usched.h>
64 #include <sys/reg.h>
65 
66 #include <vm/vm.h>
67 #include <vm/vm_param.h>
68 #include <sys/lock.h>
69 #include <vm/vm_kern.h>
70 #include <vm/vm_object.h>
71 #include <vm/vm_page.h>
72 #include <vm/vm_map.h>
73 #include <vm/vm_pager.h>
74 #include <vm/vm_extern.h>
75 
76 #include <sys/thread2.h>
77 #include <sys/mplock2.h>
78 
79 #include <sys/exec.h>
80 #include <sys/cons.h>
81 
82 #include <ddb/ddb.h>
83 
84 #include <machine/cpu.h>
85 #include <machine/clock.h>
86 #include <machine/specialreg.h>
87 #include <machine/md_var.h>
88 #include <machine/pcb.h>
89 #include <machine/pcb_ext.h>
90 #include <machine/globaldata.h>		/* CPU_prvspace */
91 #include <machine/smp.h>
92 #include <machine/cputypes.h>
93 
94 #include <bus/isa/rtc.h>
95 #include <sys/random.h>
96 #include <sys/ptrace.h>
97 #include <machine/sigframe.h>
98 #include <unistd.h>		/* umtx_* functions */
99 
100 extern void dblfault_handler (void);
101 
102 static void set_fpregs_xmm (struct save87 *, struct savexmm *);
103 static void fill_fpregs_xmm (struct savexmm *, struct save87 *);
104 
105 int64_t tsc_offsets[MAXCPU];
106 
107 #if defined(SWTCH_OPTIM_STATS)
108 extern int swtch_optim_stats;
109 SYSCTL_INT(_debug, OID_AUTO, swtch_optim_stats,
110 	CTLFLAG_RD, &swtch_optim_stats, 0, "");
111 SYSCTL_INT(_debug, OID_AUTO, tlb_flush_count,
112 	CTLFLAG_RD, &tlb_flush_count, 0, "");
113 #endif
114 
115 static int
116 sysctl_hw_physmem(SYSCTL_HANDLER_ARGS)
117 {
118 	u_long pmem = ctob(physmem);
119 	int error;
120 
121 	error = sysctl_handle_long(oidp, &pmem, 0, req);
122 
123 	return (error);
124 }
125 
126 SYSCTL_PROC(_hw, HW_PHYSMEM, physmem, CTLTYPE_ULONG|CTLFLAG_RD,
127 	0, 0, sysctl_hw_physmem, "LU", "Total system memory in bytes (number of pages * page size)");
128 
129 static int
130 sysctl_hw_usermem(SYSCTL_HANDLER_ARGS)
131 {
132 	u_long usermem = ctob(Maxmem - vmstats.v_wire_count);
133 	int error;
134 
135 	error = sysctl_handle_long(oidp, &usermem, 0, req);
136 
137 	return (error);
138 }
139 
140 SYSCTL_PROC(_hw, HW_USERMEM, usermem, CTLTYPE_ULONG|CTLFLAG_RD,
141 	0, 0, sysctl_hw_usermem, "LU", "");
142 
143 SYSCTL_ULONG(_hw, OID_AUTO, availpages, CTLFLAG_RD, &Maxmem, 0, "");
144 
145 /*
146  * Send an interrupt to process.
147  *
148  * Stack is set up to allow sigcode stored
149  * at top to call routine, followed by kcall
150  * to sigreturn routine below.  After sigreturn
151  * resets the signal mask, the stack, and the
152  * frame pointer, it returns to the user
153  * specified pc, psl.
154  */
155 void
156 sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
157 {
158 	struct lwp *lp = curthread->td_lwp;
159 	struct proc *p = lp->lwp_proc;
160 	struct trapframe *regs;
161 	struct sigacts *psp = p->p_sigacts;
162 	struct sigframe sf, *sfp;
163 	int oonstack;
164 	char *sp;
165 
166 	regs = lp->lwp_md.md_regs;
167 	oonstack = (lp->lwp_sigstk.ss_flags & SS_ONSTACK) ? 1 : 0;
168 
169 	/* Save user context */
170 	bzero(&sf, sizeof(struct sigframe));
171 	sf.sf_uc.uc_sigmask = *mask;
172 	sf.sf_uc.uc_stack = lp->lwp_sigstk;
173 	sf.sf_uc.uc_mcontext.mc_onstack = oonstack;
174 	KKASSERT(__offsetof(struct trapframe, tf_rdi) == 0);
175 	/* gcc8 craps out on -Warray-bounds w/ optimized bcopy */
176 	_bcopy(regs, &sf.sf_uc.uc_mcontext.mc_rdi, sizeof(struct trapframe));
177 
178 	/* Make the size of the saved context visible to userland */
179 	sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext);
180 
181 	/* Allocate and validate space for the signal handler context. */
182         if ((lp->lwp_flags & LWP_ALTSTACK) != 0 && !oonstack &&
183 	    SIGISMEMBER(psp->ps_sigonstack, sig)) {
184 		sp = (char *)lp->lwp_sigstk.ss_sp + lp->lwp_sigstk.ss_size -
185 		    sizeof(struct sigframe);
186 		lp->lwp_sigstk.ss_flags |= SS_ONSTACK;
187 	} else {
188 		/* We take red zone into account */
189 		sp = (char *)regs->tf_rsp - sizeof(struct sigframe) - 128;
190 	}
191 
192 	/* Align to 16 bytes */
193 	sfp = (struct sigframe *)((intptr_t)sp & ~0xFUL);
194 
195 	/* Translate the signal is appropriate */
196 	if (p->p_sysent->sv_sigtbl) {
197 		if (sig <= p->p_sysent->sv_sigsize)
198 			sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
199 	}
200 
201 	/*
202 	 * Build the argument list for the signal handler.
203 	 *
204 	 * Arguments are in registers (%rdi, %rsi, %rdx, %rcx)
205 	 */
206 	regs->tf_rdi = sig;				/* argument 1 */
207 	regs->tf_rdx = (register_t)&sfp->sf_uc;		/* argument 3 */
208 
209 	if (SIGISMEMBER(psp->ps_siginfo, sig)) {
210 		/*
211 		 * Signal handler installed with SA_SIGINFO.
212 		 *
213 		 * action(signo, siginfo, ucontext)
214 		 */
215 		regs->tf_rsi = (register_t)&sfp->sf_si;	/* argument 2 */
216 		regs->tf_rcx = (register_t)regs->tf_err; /* argument 4 */
217 		sf.sf_ahu.sf_action = (__siginfohandler_t *)catcher;
218 
219 		/* fill siginfo structure */
220 		sf.sf_si.si_signo = sig;
221 		sf.sf_si.si_pid = psp->ps_frominfo[sig].pid;
222 		sf.sf_si.si_uid = psp->ps_frominfo[sig].uid;
223 		sf.sf_si.si_code = code;
224 		sf.sf_si.si_addr = (void *)regs->tf_addr;
225 	} else {
226 		/*
227 		 * Old FreeBSD-style arguments.
228 		 *
229 		 * handler (signo, code, [uc], addr)
230 		 */
231 		regs->tf_rsi = (register_t)code;	/* argument 2 */
232 		regs->tf_rcx = (register_t)regs->tf_addr; /* argument 4 */
233 		sf.sf_ahu.sf_handler = catcher;
234 	}
235 
236 #if 0
237 	/*
238 	 * If we're a vm86 process, we want to save the segment registers.
239 	 * We also change eflags to be our emulated eflags, not the actual
240 	 * eflags.
241 	 */
242 	if (regs->tf_eflags & PSL_VM) {
243 		struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
244 		struct vm86_kernel *vm86 = &lp->lwp_thread->td_pcb->pcb_ext->ext_vm86;
245 
246 		sf.sf_uc.uc_mcontext.mc_gs = tf->tf_vm86_gs;
247 		sf.sf_uc.uc_mcontext.mc_fs = tf->tf_vm86_fs;
248 		sf.sf_uc.uc_mcontext.mc_es = tf->tf_vm86_es;
249 		sf.sf_uc.uc_mcontext.mc_ds = tf->tf_vm86_ds;
250 
251 		if (vm86->vm86_has_vme == 0)
252 			sf.sf_uc.uc_mcontext.mc_eflags =
253 			    (tf->tf_eflags & ~(PSL_VIF | PSL_VIP)) |
254 			    (vm86->vm86_eflags & (PSL_VIF | PSL_VIP));
255 
256 		/*
257 		 * Clear PSL_NT to inhibit T_TSSFLT faults on return from
258 		 * syscalls made by the signal handler.  This just avoids
259 		 * wasting time for our lazy fixup of such faults.  PSL_NT
260 		 * does nothing in vm86 mode, but vm86 programs can set it
261 		 * almost legitimately in probes for old cpu types.
262 		 */
263 		tf->tf_eflags &= ~(PSL_VM | PSL_NT | PSL_VIF | PSL_VIP);
264 	}
265 #endif
266 
267 	/*
268 	 * Save the FPU state and reinit the FP unit
269 	 */
270 	npxpush(&sf.sf_uc.uc_mcontext);
271 
272 	/*
273 	 * Copy the sigframe out to the user's stack.
274 	 */
275 	if (copyout(&sf, sfp, sizeof(struct sigframe)) != 0) {
276 		/*
277 		 * Something is wrong with the stack pointer.
278 		 * ...Kill the process.
279 		 */
280 		sigexit(lp, SIGILL);
281 	}
282 
283 	regs->tf_rsp = (register_t)sfp;
284 	regs->tf_rip = trunc_page64(PS_STRINGS - *(p->p_sysent->sv_szsigcode));
285 	regs->tf_rip -= SZSIGCODE_EXTRA_BYTES;
286 
287 	/*
288 	 * x86 abi specifies that the direction flag must be cleared
289 	 * on function entry
290 	 */
291 	regs->tf_rflags &= ~(PSL_T|PSL_D);
292 
293 	/*
294 	 * 64 bit mode has a code and stack selector but
295 	 * no data or extra selector.  %fs and %gs are not
296 	 * stored in-context.
297 	 */
298 	regs->tf_cs = _ucodesel;
299 	regs->tf_ss = _udatasel;
300 }
301 
302 /*
303  * Sanitize the trapframe for a virtual kernel passing control to a custom
304  * VM context.  Remove any items that would otherwise create a privilage
305  * issue.
306  *
307  * XXX at the moment we allow userland to set the resume flag.  Is this a
308  * bad idea?
309  */
310 int
311 cpu_sanitize_frame(struct trapframe *frame)
312 {
313 	frame->tf_cs = _ucodesel;
314 	frame->tf_ss = _udatasel;
315 	/* XXX VM (8086) mode not supported? */
316 	frame->tf_rflags &= (PSL_RF | PSL_USERCHANGE | PSL_VM_UNSUPP);
317 	frame->tf_rflags |= PSL_RESERVED_DEFAULT | PSL_I;
318 
319 	return(0);
320 }
321 
322 /*
323  * Sanitize the tls so loading the descriptor does not blow up
324  * on us.  For x86_64 we don't have to do anything.
325  */
326 int
327 cpu_sanitize_tls(struct savetls *tls)
328 {
329 	return(0);
330 }
331 
332 /*
333  * sigreturn(ucontext_t *sigcntxp)
334  *
335  * System call to cleanup state after a signal
336  * has been taken.  Reset signal mask and
337  * stack state from context left by sendsig (above).
338  * Return to previous pc and psl as specified by
339  * context left by sendsig. Check carefully to
340  * make sure that the user has not modified the
341  * state to gain improper privileges.
342  */
343 #define	EFL_SECURE(ef, oef)	((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
344 #define	CS_SECURE(cs)		(ISPL(cs) == SEL_UPL)
345 
346 int
347 sys_sigreturn(struct sigreturn_args *uap)
348 {
349 	struct lwp *lp = curthread->td_lwp;
350 	struct trapframe *regs;
351 	ucontext_t uc;
352 	ucontext_t *ucp;
353 	register_t rflags;
354 	int cs;
355 	int error;
356 
357 	/*
358 	 * We have to copy the information into kernel space so userland
359 	 * can't modify it while we are sniffing it.
360 	 */
361 	regs = lp->lwp_md.md_regs;
362 	error = copyin(uap->sigcntxp, &uc, sizeof(uc));
363 	if (error)
364 		return (error);
365 	ucp = &uc;
366 	rflags = ucp->uc_mcontext.mc_rflags;
367 
368 	/* VM (8086) mode not supported */
369 	rflags &= ~PSL_VM_UNSUPP;
370 
371 #if 0
372 	if (eflags & PSL_VM) {
373 		struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
374 		struct vm86_kernel *vm86;
375 
376 		/*
377 		 * if pcb_ext == 0 or vm86_inited == 0, the user hasn't
378 		 * set up the vm86 area, and we can't enter vm86 mode.
379 		 */
380 		if (lp->lwp_thread->td_pcb->pcb_ext == 0)
381 			return (EINVAL);
382 		vm86 = &lp->lwp_thread->td_pcb->pcb_ext->ext_vm86;
383 		if (vm86->vm86_inited == 0)
384 			return (EINVAL);
385 
386 		/* go back to user mode if both flags are set */
387 		if ((eflags & PSL_VIP) && (eflags & PSL_VIF))
388 			trapsignal(lp->lwp_proc, SIGBUS, 0);
389 
390 		if (vm86->vm86_has_vme) {
391 			eflags = (tf->tf_eflags & ~VME_USERCHANGE) |
392 			    (eflags & VME_USERCHANGE) | PSL_VM;
393 		} else {
394 			vm86->vm86_eflags = eflags;	/* save VIF, VIP */
395 			eflags = (tf->tf_eflags & ~VM_USERCHANGE) |					    (eflags & VM_USERCHANGE) | PSL_VM;
396 		}
397 		bcopy(&ucp.uc_mcontext.mc_gs, tf, sizeof(struct trapframe));
398 		tf->tf_eflags = eflags;
399 		tf->tf_vm86_ds = tf->tf_ds;
400 		tf->tf_vm86_es = tf->tf_es;
401 		tf->tf_vm86_fs = tf->tf_fs;
402 		tf->tf_vm86_gs = tf->tf_gs;
403 		tf->tf_ds = _udatasel;
404 		tf->tf_es = _udatasel;
405 #if 0
406 		tf->tf_fs = _udatasel;
407 		tf->tf_gs = _udatasel;
408 #endif
409 	} else
410 #endif
411 	{
412 		/*
413 		 * Don't allow users to change privileged or reserved flags.
414 		 */
415 		/*
416 		 * XXX do allow users to change the privileged flag PSL_RF.
417 		 * The cpu sets PSL_RF in tf_eflags for faults.  Debuggers
418 		 * should sometimes set it there too.  tf_eflags is kept in
419 		 * the signal context during signal handling and there is no
420 		 * other place to remember it, so the PSL_RF bit may be
421 		 * corrupted by the signal handler without us knowing.
422 		 * Corruption of the PSL_RF bit at worst causes one more or
423 		 * one less debugger trap, so allowing it is fairly harmless.
424 		 */
425 		if (!EFL_SECURE(rflags & ~PSL_RF, regs->tf_rflags & ~PSL_RF)) {
426 			kprintf("sigreturn: rflags = 0x%lx\n", (long)rflags);
427 			return(EINVAL);
428 		}
429 
430 		/*
431 		 * Don't allow users to load a valid privileged %cs.  Let the
432 		 * hardware check for invalid selectors, excess privilege in
433 		 * other selectors, invalid %eip's and invalid %esp's.
434 		 */
435 		cs = ucp->uc_mcontext.mc_cs;
436 		if (!CS_SECURE(cs)) {
437 			kprintf("sigreturn: cs = 0x%x\n", cs);
438 			trapsignal(lp, SIGBUS, T_PROTFLT);
439 			return(EINVAL);
440 		}
441 		bcopy(&ucp->uc_mcontext.mc_rdi, regs, sizeof(struct trapframe));
442 	}
443 
444 	/*
445 	 * Restore the FPU state from the frame
446 	 */
447 	npxpop(&ucp->uc_mcontext);
448 
449 	if (ucp->uc_mcontext.mc_onstack & 1)
450 		lp->lwp_sigstk.ss_flags |= SS_ONSTACK;
451 	else
452 		lp->lwp_sigstk.ss_flags &= ~SS_ONSTACK;
453 
454 	lp->lwp_sigmask = ucp->uc_sigmask;
455 	SIG_CANTMASK(lp->lwp_sigmask);
456 	return(EJUSTRETURN);
457 }
458 
459 /*
460  * cpu_idle() represents the idle LWKT.  You cannot return from this function
461  * (unless you want to blow things up!).  Instead we look for runnable threads
462  * and loop or halt as appropriate.  Giant is not held on entry to the thread.
463  *
464  * The main loop is entered with a critical section held, we must release
465  * the critical section before doing anything else.  lwkt_switch() will
466  * check for pending interrupts due to entering and exiting its own
467  * critical section.
468  *
469  * Note on cpu_idle_hlt:  On an SMP system we rely on a scheduler IPI
470  * to wake a HLTed cpu up.
471  */
472 __read_mostly static int	cpu_idle_hlt = 1;
473 SYSCTL_INT(_machdep, OID_AUTO, cpu_idle_hlt, CTLFLAG_RW,
474     &cpu_idle_hlt, 0, "Idle loop HLT enable");
475 
476 void
477 cpu_idle(void)
478 {
479 	struct thread *td = curthread;
480 	struct mdglobaldata *gd = mdcpu;
481 	int reqflags;
482 
483 	crit_exit();
484 	KKASSERT(td->td_critcount == 0);
485 	cpu_enable_intr();
486 
487 	for (;;) {
488 		/*
489 		 * See if there are any LWKTs ready to go.
490 		 */
491 		lwkt_switch();
492 
493 		/*
494 		 * The idle loop halts only if no threads are scheduleable
495 		 * and no signals have occured.
496 		 */
497 		if (cpu_idle_hlt &&
498 		    (td->td_gd->gd_reqflags & RQF_IDLECHECK_WK_MASK) == 0) {
499 			splz();
500 			if ((td->td_gd->gd_reqflags & RQF_IDLECHECK_WK_MASK) == 0) {
501 #ifdef DEBUGIDLE
502 				struct timeval tv1, tv2;
503 				gettimeofday(&tv1, NULL);
504 #endif
505 				reqflags = gd->mi.gd_reqflags &
506 					   ~RQF_IDLECHECK_WK_MASK;
507 				KKASSERT(gd->mi.gd_processing_ipiq == 0);
508 				umtx_sleep(&gd->mi.gd_reqflags, reqflags,
509 					   1000000);
510 #ifdef DEBUGIDLE
511 				gettimeofday(&tv2, NULL);
512 				if (tv2.tv_usec - tv1.tv_usec +
513 				    (tv2.tv_sec - tv1.tv_sec) * 1000000
514 				    > 500000) {
515 					kprintf("cpu %d idlelock %08x %08x\n",
516 						gd->mi.gd_cpuid,
517 						gd->mi.gd_reqflags,
518 						gd->gd_fpending);
519 				}
520 #endif
521 			}
522 		} else {
523 			splz();
524 			__asm __volatile("pause");
525 		}
526 	}
527 }
528 
529 /*
530  * Called by the spinlock code with or without a critical section held
531  * when a spinlock is found to be seriously constested.
532  *
533  * We need to enter a critical section to prevent signals from recursing
534  * into pthreads.
535  */
536 void
537 cpu_spinlock_contested(void)
538 {
539 	cpu_pause();
540 }
541 
542 /*
543  * Clear registers on exec
544  */
545 void
546 exec_setregs(u_long entry, u_long stack, u_long ps_strings)
547 {
548 	struct thread *td = curthread;
549 	struct lwp *lp = td->td_lwp;
550 	struct pcb *pcb = td->td_pcb;
551 	struct trapframe *regs = lp->lwp_md.md_regs;
552 
553 	user_ldt_free(pcb);
554 
555 	bzero((char *)regs, sizeof(struct trapframe));
556 	regs->tf_rip = entry;
557 	regs->tf_rsp = ((stack - 8) & ~0xFul) + 8; /* align the stack */
558 	regs->tf_rdi = stack;		/* argv */
559 	regs->tf_rflags = PSL_USER | (regs->tf_rflags & PSL_T);
560 	regs->tf_ss = _udatasel;
561 	regs->tf_cs = _ucodesel;
562 	regs->tf_rbx = ps_strings;
563 
564 	/*
565 	 * Reset the hardware debug registers if they were in use.
566 	 * They won't have any meaning for the newly exec'd process.
567 	 */
568 	if (pcb->pcb_flags & PCB_DBREGS) {
569 		pcb->pcb_dr0 = 0;
570 		pcb->pcb_dr1 = 0;
571 		pcb->pcb_dr2 = 0;
572 		pcb->pcb_dr3 = 0;
573 		pcb->pcb_dr6 = 0;
574 		pcb->pcb_dr7 = 0; /* JG set bit 10? */
575 		if (pcb == td->td_pcb) {
576 			/*
577 			 * Clear the debug registers on the running
578 			 * CPU, otherwise they will end up affecting
579 			 * the next process we switch to.
580 			 */
581 			reset_dbregs();
582 		}
583 		pcb->pcb_flags &= ~PCB_DBREGS;
584 	}
585 
586 	/*
587 	 * Initialize the math emulator (if any) for the current process.
588 	 * Actually, just clear the bit that says that the emulator has
589 	 * been initialized.  Initialization is delayed until the process
590 	 * traps to the emulator (if it is done at all) mainly because
591 	 * emulators don't provide an entry point for initialization.
592 	 */
593 	pcb->pcb_flags &= ~FP_SOFTFP;
594 
595 	/*
596 	 * NOTE: do not set CR0_TS here.  npxinit() must do it after clearing
597 	 *	 gd_npxthread.  Otherwise a preemptive interrupt thread
598 	 *	 may panic in npxdna().
599 	 */
600 	crit_enter();
601 #if 0
602 	load_cr0(rcr0() | CR0_MP);
603 #endif
604 
605 	/*
606 	 * NOTE: The MSR values must be correct so we can return to
607 	 *	 userland.  gd_user_fs/gs must be correct so the switch
608 	 *	 code knows what the current MSR values are.
609 	 */
610 	pcb->pcb_fsbase = 0;	/* Values loaded from PCB on switch */
611 	pcb->pcb_gsbase = 0;
612 	/* Initialize the npx (if any) for the current process. */
613 	npxinit();
614 	crit_exit();
615 
616 	/*
617 	 * note: linux emulator needs edx to be 0x0 on entry, which is
618 	 * handled in execve simply by setting the 64 bit syscall
619 	 * return value to 0.
620 	 */
621 }
622 
623 void
624 cpu_setregs(void)
625 {
626 #if 0
627 	unsigned int cr0;
628 
629 	cr0 = rcr0();
630 	cr0 |= CR0_NE;			/* Done by npxinit() */
631 	cr0 |= CR0_MP | CR0_TS;		/* Done at every execve() too. */
632 	cr0 |= CR0_WP | CR0_AM;
633 	load_cr0(cr0);
634 	load_gs(_udatasel);
635 #endif
636 }
637 
638 static int
639 sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
640 {
641 	int error;
642 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2,
643 		req);
644 	if (!error && req->newptr)
645 		resettodr();
646 	return (error);
647 }
648 
649 SYSCTL_PROC(_machdep, CPU_ADJKERNTZ, adjkerntz, CTLTYPE_INT|CTLFLAG_RW,
650 	&adjkerntz, 0, sysctl_machdep_adjkerntz, "I", "");
651 
652 /*
653  * Initialize x86 and configure to run kernel
654  */
655 
656 /*
657  * Initialize segments & interrupt table
658  */
659 
660 extern  struct user *proc0paddr;
661 
662 #if 0
663 
664 extern inthand_t
665 	IDTVEC(div), IDTVEC(dbg), IDTVEC(nmi), IDTVEC(bpt), IDTVEC(ofl),
666 	IDTVEC(bnd), IDTVEC(ill), IDTVEC(dna), IDTVEC(fpusegm),
667 	IDTVEC(tss), IDTVEC(missing), IDTVEC(stk), IDTVEC(prot),
668 	IDTVEC(page), IDTVEC(mchk), IDTVEC(rsvd), IDTVEC(fpu), IDTVEC(align),
669 	IDTVEC(xmm), IDTVEC(dblfault),
670 	IDTVEC(fast_syscall), IDTVEC(fast_syscall32);
671 #endif
672 
673 int
674 ptrace_set_pc(struct lwp *lp, unsigned long addr)
675 {
676 	lp->lwp_md.md_regs->tf_rip = addr;
677 	return (0);
678 }
679 
680 int
681 ptrace_single_step(struct lwp *lp)
682 {
683 	lp->lwp_md.md_regs->tf_rflags |= PSL_T;
684 	return (0);
685 }
686 
687 int
688 fill_regs(struct lwp *lp, struct reg *regs)
689 {
690 	struct trapframe *tp;
691 
692 	if ((tp = lp->lwp_md.md_regs) == NULL)
693 		return EINVAL;
694 	bcopy(&tp->tf_rdi, &regs->r_rdi, sizeof(*regs));
695 	return (0);
696 }
697 
698 int
699 set_regs(struct lwp *lp, struct reg *regs)
700 {
701 	struct trapframe *tp;
702 
703 	tp = lp->lwp_md.md_regs;
704 	if (!EFL_SECURE(regs->r_rflags, tp->tf_rflags) ||
705 	    !CS_SECURE(regs->r_cs))
706 		return (EINVAL);
707 	bcopy(&regs->r_rdi, &tp->tf_rdi, sizeof(*regs));
708 	return (0);
709 }
710 
711 static void
712 fill_fpregs_xmm(struct savexmm *sv_xmm, struct save87 *sv_87)
713 {
714 	struct env87 *penv_87 = &sv_87->sv_env;
715 	struct envxmm *penv_xmm = &sv_xmm->sv_env;
716 	int i;
717 
718 	/* FPU control/status */
719 	penv_87->en_cw = penv_xmm->en_cw;
720 	penv_87->en_sw = penv_xmm->en_sw;
721 	penv_87->en_tw = penv_xmm->en_tw;
722 	penv_87->en_fip = penv_xmm->en_fip;
723 	penv_87->en_fcs = penv_xmm->en_fcs;
724 	penv_87->en_opcode = penv_xmm->en_opcode;
725 	penv_87->en_foo = penv_xmm->en_foo;
726 	penv_87->en_fos = penv_xmm->en_fos;
727 
728 	/* FPU registers */
729 	for (i = 0; i < 8; ++i)
730 		sv_87->sv_ac[i] = sv_xmm->sv_fp[i].fp_acc;
731 }
732 
733 static void
734 set_fpregs_xmm(struct save87 *sv_87, struct savexmm *sv_xmm)
735 {
736 	struct env87 *penv_87 = &sv_87->sv_env;
737 	struct envxmm *penv_xmm = &sv_xmm->sv_env;
738 	int i;
739 
740 	/* FPU control/status */
741 	penv_xmm->en_cw = penv_87->en_cw;
742 	penv_xmm->en_sw = penv_87->en_sw;
743 	penv_xmm->en_tw = penv_87->en_tw;
744 	penv_xmm->en_fip = penv_87->en_fip;
745 	penv_xmm->en_fcs = penv_87->en_fcs;
746 	penv_xmm->en_opcode = penv_87->en_opcode;
747 	penv_xmm->en_foo = penv_87->en_foo;
748 	penv_xmm->en_fos = penv_87->en_fos;
749 
750 	/* FPU registers */
751 	for (i = 0; i < 8; ++i)
752 		sv_xmm->sv_fp[i].fp_acc = sv_87->sv_ac[i];
753 }
754 
755 int
756 fill_fpregs(struct lwp *lp, struct fpreg *fpregs)
757 {
758 	if (lp->lwp_thread == NULL || lp->lwp_thread->td_pcb == NULL)
759 		return EINVAL;
760 	if (cpu_fxsr) {
761 		fill_fpregs_xmm(&lp->lwp_thread->td_pcb->pcb_save.sv_xmm,
762 				(struct save87 *)fpregs);
763 		return (0);
764 	}
765 	bcopy(&lp->lwp_thread->td_pcb->pcb_save.sv_87, fpregs, sizeof *fpregs);
766 	return (0);
767 }
768 
769 int
770 set_fpregs(struct lwp *lp, struct fpreg *fpregs)
771 {
772 	if (cpu_fxsr) {
773 		set_fpregs_xmm((struct save87 *)fpregs,
774 			       &lp->lwp_thread->td_pcb->pcb_save.sv_xmm);
775 		return (0);
776 	}
777 	bcopy(fpregs, &lp->lwp_thread->td_pcb->pcb_save.sv_87, sizeof *fpregs);
778 	return (0);
779 }
780 
781 int
782 fill_dbregs(struct lwp *lp, struct dbreg *dbregs)
783 {
784 	return (ENOSYS);
785 }
786 
787 int
788 set_dbregs(struct lwp *lp, struct dbreg *dbregs)
789 {
790 	return (ENOSYS);
791 }
792 
793 #if 0
794 /*
795  * Return > 0 if a hardware breakpoint has been hit, and the
796  * breakpoint was in user space.  Return 0, otherwise.
797  */
798 int
799 user_dbreg_trap(void)
800 {
801         u_int32_t dr7, dr6; /* debug registers dr6 and dr7 */
802         u_int32_t bp;       /* breakpoint bits extracted from dr6 */
803         int nbp;            /* number of breakpoints that triggered */
804         caddr_t addr[4];    /* breakpoint addresses */
805         int i;
806 
807         dr7 = rdr7();
808         if ((dr7 & 0x000000ff) == 0) {
809                 /*
810                  * all GE and LE bits in the dr7 register are zero,
811                  * thus the trap couldn't have been caused by the
812                  * hardware debug registers
813                  */
814                 return 0;
815         }
816 
817         nbp = 0;
818         dr6 = rdr6();
819         bp = dr6 & 0x0000000f;
820 
821         if (!bp) {
822                 /*
823                  * None of the breakpoint bits are set meaning this
824                  * trap was not caused by any of the debug registers
825                  */
826                 return 0;
827         }
828 
829         /*
830          * at least one of the breakpoints were hit, check to see
831          * which ones and if any of them are user space addresses
832          */
833 
834         if (bp & 0x01) {
835                 addr[nbp++] = (caddr_t)rdr0();
836         }
837         if (bp & 0x02) {
838                 addr[nbp++] = (caddr_t)rdr1();
839         }
840         if (bp & 0x04) {
841                 addr[nbp++] = (caddr_t)rdr2();
842         }
843         if (bp & 0x08) {
844                 addr[nbp++] = (caddr_t)rdr3();
845         }
846 
847         for (i=0; i<nbp; i++) {
848                 if (addr[i] <
849                     (caddr_t)VM_MAX_USER_ADDRESS) {
850                         /*
851                          * addr[i] is in user space
852                          */
853                         return nbp;
854                 }
855         }
856 
857         /*
858          * None of the breakpoints are in user space.
859          */
860         return 0;
861 }
862 
863 #endif
864 
865 void
866 identcpu(void)
867 {
868 	int regs[4];
869 
870 	do_cpuid(1, regs);
871 	cpu_feature = regs[3];
872 }
873 
874 
875 #ifndef DDB
876 void
877 Debugger(const char *msg)
878 {
879 	kprintf("Debugger(\"%s\") called.\n", msg);
880 }
881 #endif /* no DDB */
882