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_compat.h"
43 #include "opt_ddb.h"
44 #include "opt_directio.h"
45 #include "opt_inet.h"
46 #include "opt_msgbuf.h"
47 #include "opt_swap.h"
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/sysproto.h>
52 #include <sys/signalvar.h>
53 #include <sys/kernel.h>
54 #include <sys/linker.h>
55 #include <sys/malloc.h>
56 #include <sys/proc.h>
57 #include <sys/buf.h>
58 #include <sys/reboot.h>
59 #include <sys/mbuf.h>
60 #include <sys/msgbuf.h>
61 #include <sys/sysent.h>
62 #include <sys/sysctl.h>
63 #include <sys/vmmeter.h>
64 #include <sys/bus.h>
65 #include <sys/usched.h>
66 #include <sys/reg.h>
67 
68 #include <vm/vm.h>
69 #include <vm/vm_param.h>
70 #include <sys/lock.h>
71 #include <vm/vm_kern.h>
72 #include <vm/vm_object.h>
73 #include <vm/vm_page.h>
74 #include <vm/vm_map.h>
75 #include <vm/vm_pager.h>
76 #include <vm/vm_extern.h>
77 
78 #include <sys/thread2.h>
79 #include <sys/mplock2.h>
80 
81 #include <sys/user.h>
82 #include <sys/exec.h>
83 #include <sys/cons.h>
84 
85 #include <ddb/ddb.h>
86 
87 #include <machine/cpu.h>
88 #include <machine/clock.h>
89 #include <machine/specialreg.h>
90 #include <machine/md_var.h>
91 #include <machine/pcb_ext.h>		/* pcb.h included via sys/user.h */
92 #include <machine/globaldata.h>		/* CPU_prvspace */
93 #include <machine/smp.h>
94 #ifdef PERFMON
95 #include <machine/perfmon.h>
96 #endif
97 #include <machine/cputypes.h>
98 
99 #include <bus/isa/rtc.h>
100 #include <sys/random.h>
101 #include <sys/ptrace.h>
102 #include <machine/sigframe.h>
103 #include <unistd.h>		/* umtx_* functions */
104 #include <pthread.h>		/* pthread_yield() */
105 
106 extern void dblfault_handler (void);
107 
108 #ifndef CPU_DISABLE_SSE
109 static void set_fpregs_xmm (struct save87 *, struct savexmm *);
110 static void fill_fpregs_xmm (struct savexmm *, struct save87 *);
111 #endif /* CPU_DISABLE_SSE */
112 #ifdef DIRECTIO
113 extern void ffs_rawread_setup(void);
114 #endif /* DIRECTIO */
115 
116 int64_t tsc_offsets[MAXCPU];
117 
118 #if defined(SWTCH_OPTIM_STATS)
119 extern int swtch_optim_stats;
120 SYSCTL_INT(_debug, OID_AUTO, swtch_optim_stats,
121 	CTLFLAG_RD, &swtch_optim_stats, 0, "");
122 SYSCTL_INT(_debug, OID_AUTO, tlb_flush_count,
123 	CTLFLAG_RD, &tlb_flush_count, 0, "");
124 #endif
125 
126 static int
127 sysctl_hw_physmem(SYSCTL_HANDLER_ARGS)
128 {
129 	u_long pmem = ctob(physmem);
130 
131 	int error = sysctl_handle_long(oidp, &pmem, 0, req);
132 	return (error);
133 }
134 
135 SYSCTL_PROC(_hw, HW_PHYSMEM, physmem, CTLTYPE_ULONG|CTLFLAG_RD,
136 	0, 0, sysctl_hw_physmem, "LU", "Total system memory in bytes (number of pages * page size)");
137 
138 static int
139 sysctl_hw_usermem(SYSCTL_HANDLER_ARGS)
140 {
141 	/* JG */
142 	int error = sysctl_handle_int(oidp, 0,
143 		ctob((int)Maxmem - vmstats.v_wire_count), req);
144 	return (error);
145 }
146 
147 SYSCTL_PROC(_hw, HW_USERMEM, usermem, CTLTYPE_INT|CTLFLAG_RD,
148 	0, 0, sysctl_hw_usermem, "IU", "");
149 
150 SYSCTL_ULONG(_hw, OID_AUTO, availpages, CTLFLAG_RD, &Maxmem, 0, "");
151 
152 #if 0
153 
154 static int
155 sysctl_machdep_msgbuf(SYSCTL_HANDLER_ARGS)
156 {
157 	int error;
158 
159 	/* Unwind the buffer, so that it's linear (possibly starting with
160 	 * some initial nulls).
161 	 */
162 	error=sysctl_handle_opaque(oidp,msgbufp->msg_ptr+msgbufp->msg_bufr,
163 		msgbufp->msg_size-msgbufp->msg_bufr,req);
164 	if(error) return(error);
165 	if(msgbufp->msg_bufr>0) {
166 		error=sysctl_handle_opaque(oidp,msgbufp->msg_ptr,
167 			msgbufp->msg_bufr,req);
168 	}
169 	return(error);
170 }
171 
172 SYSCTL_PROC(_machdep, OID_AUTO, msgbuf, CTLTYPE_STRING|CTLFLAG_RD,
173 	0, 0, sysctl_machdep_msgbuf, "A","Contents of kernel message buffer");
174 
175 static int msgbuf_clear;
176 
177 static int
178 sysctl_machdep_msgbuf_clear(SYSCTL_HANDLER_ARGS)
179 {
180 	int error;
181 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2,
182 		req);
183 	if (!error && req->newptr) {
184 		/* Clear the buffer and reset write pointer */
185 		bzero(msgbufp->msg_ptr,msgbufp->msg_size);
186 		msgbufp->msg_bufr=msgbufp->msg_bufx=0;
187 		msgbuf_clear=0;
188 	}
189 	return (error);
190 }
191 
192 SYSCTL_PROC(_machdep, OID_AUTO, msgbuf_clear, CTLTYPE_INT|CTLFLAG_RW,
193 	&msgbuf_clear, 0, sysctl_machdep_msgbuf_clear, "I",
194 	"Clear kernel message buffer");
195 
196 #endif
197 
198 /*
199  * Send an interrupt to process.
200  *
201  * Stack is set up to allow sigcode stored
202  * at top to call routine, followed by kcall
203  * to sigreturn routine below.  After sigreturn
204  * resets the signal mask, the stack, and the
205  * frame pointer, it returns to the user
206  * specified pc, psl.
207  */
208 void
209 sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
210 {
211 	struct lwp *lp = curthread->td_lwp;
212 	struct proc *p = lp->lwp_proc;
213 	struct trapframe *regs;
214 	struct sigacts *psp = p->p_sigacts;
215 	struct sigframe sf, *sfp;
216 	int oonstack;
217 	char *sp;
218 
219 	regs = lp->lwp_md.md_regs;
220 	oonstack = (lp->lwp_sigstk.ss_flags & SS_ONSTACK) ? 1 : 0;
221 
222 	/* Save user context */
223 	bzero(&sf, sizeof(struct sigframe));
224 	sf.sf_uc.uc_sigmask = *mask;
225 	sf.sf_uc.uc_stack = lp->lwp_sigstk;
226 	sf.sf_uc.uc_mcontext.mc_onstack = oonstack;
227 	KKASSERT(__offsetof(struct trapframe, tf_rdi) == 0);
228 	bcopy(regs, &sf.sf_uc.uc_mcontext.mc_rdi, sizeof(struct trapframe));
229 
230 	/* Make the size of the saved context visible to userland */
231 	sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext);
232 
233 	/* Allocate and validate space for the signal handler context. */
234         if ((lp->lwp_flags & LWP_ALTSTACK) != 0 && !oonstack &&
235 	    SIGISMEMBER(psp->ps_sigonstack, sig)) {
236 		sp = (char *)(lp->lwp_sigstk.ss_sp + lp->lwp_sigstk.ss_size -
237 			      sizeof(struct sigframe));
238 		lp->lwp_sigstk.ss_flags |= SS_ONSTACK;
239 	} else {
240 		/* We take red zone into account */
241 		sp = (char *)regs->tf_rsp - sizeof(struct sigframe) - 128;
242 	}
243 
244 	/* Align to 16 bytes */
245 	sfp = (struct sigframe *)((intptr_t)sp & ~0xFUL);
246 
247 	/* Translate the signal is appropriate */
248 	if (p->p_sysent->sv_sigtbl) {
249 		if (sig <= p->p_sysent->sv_sigsize)
250 			sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
251 	}
252 
253 	/*
254 	 * Build the argument list for the signal handler.
255 	 *
256 	 * Arguments are in registers (%rdi, %rsi, %rdx, %rcx)
257 	 */
258 	regs->tf_rdi = sig;				/* argument 1 */
259 	regs->tf_rdx = (register_t)&sfp->sf_uc;		/* argument 3 */
260 
261 	if (SIGISMEMBER(psp->ps_siginfo, sig)) {
262 		/*
263 		 * Signal handler installed with SA_SIGINFO.
264 		 *
265 		 * action(signo, siginfo, ucontext)
266 		 */
267 		regs->tf_rsi = (register_t)&sfp->sf_si;	/* argument 2 */
268 		regs->tf_rcx = (register_t)regs->tf_err; /* argument 4 */
269 		sf.sf_ahu.sf_action = (__siginfohandler_t *)catcher;
270 
271 		/* fill siginfo structure */
272 		sf.sf_si.si_signo = sig;
273 		sf.sf_si.si_code = code;
274 		sf.sf_si.si_addr = (void *)regs->tf_addr;
275 	} else {
276 		/*
277 		 * Old FreeBSD-style arguments.
278 		 *
279 		 * handler (signo, code, [uc], addr)
280 		 */
281 		regs->tf_rsi = (register_t)code;	/* argument 2 */
282 		regs->tf_rcx = (register_t)regs->tf_addr; /* argument 4 */
283 		sf.sf_ahu.sf_handler = catcher;
284 	}
285 
286 #if 0
287 	/*
288 	 * If we're a vm86 process, we want to save the segment registers.
289 	 * We also change eflags to be our emulated eflags, not the actual
290 	 * eflags.
291 	 */
292 	if (regs->tf_eflags & PSL_VM) {
293 		struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
294 		struct vm86_kernel *vm86 = &lp->lwp_thread->td_pcb->pcb_ext->ext_vm86;
295 
296 		sf.sf_uc.uc_mcontext.mc_gs = tf->tf_vm86_gs;
297 		sf.sf_uc.uc_mcontext.mc_fs = tf->tf_vm86_fs;
298 		sf.sf_uc.uc_mcontext.mc_es = tf->tf_vm86_es;
299 		sf.sf_uc.uc_mcontext.mc_ds = tf->tf_vm86_ds;
300 
301 		if (vm86->vm86_has_vme == 0)
302 			sf.sf_uc.uc_mcontext.mc_eflags =
303 			    (tf->tf_eflags & ~(PSL_VIF | PSL_VIP)) |
304 			    (vm86->vm86_eflags & (PSL_VIF | PSL_VIP));
305 
306 		/*
307 		 * Clear PSL_NT to inhibit T_TSSFLT faults on return from
308 		 * syscalls made by the signal handler.  This just avoids
309 		 * wasting time for our lazy fixup of such faults.  PSL_NT
310 		 * does nothing in vm86 mode, but vm86 programs can set it
311 		 * almost legitimately in probes for old cpu types.
312 		 */
313 		tf->tf_eflags &= ~(PSL_VM | PSL_NT | PSL_VIF | PSL_VIP);
314 	}
315 #endif
316 
317 	/*
318 	 * Save the FPU state and reinit the FP unit
319 	 */
320 	npxpush(&sf.sf_uc.uc_mcontext);
321 
322 	/*
323 	 * Copy the sigframe out to the user's stack.
324 	 */
325 	if (copyout(&sf, sfp, sizeof(struct sigframe)) != 0) {
326 		/*
327 		 * Something is wrong with the stack pointer.
328 		 * ...Kill the process.
329 		 */
330 		sigexit(lp, SIGILL);
331 	}
332 
333 	regs->tf_rsp = (register_t)sfp;
334 	regs->tf_rip = PS_STRINGS - *(p->p_sysent->sv_szsigcode);
335 
336 	/*
337 	 * i386 abi specifies that the direction flag must be cleared
338 	 * on function entry
339 	 */
340 	regs->tf_rflags &= ~(PSL_T|PSL_D);
341 
342 	/*
343 	 * 64 bit mode has a code and stack selector but
344 	 * no data or extra selector.  %fs and %gs are not
345 	 * stored in-context.
346 	 */
347 	regs->tf_cs = _ucodesel;
348 	regs->tf_ss = _udatasel;
349 }
350 
351 /*
352  * Sanitize the trapframe for a virtual kernel passing control to a custom
353  * VM context.  Remove any items that would otherwise create a privilage
354  * issue.
355  *
356  * XXX at the moment we allow userland to set the resume flag.  Is this a
357  * bad idea?
358  */
359 int
360 cpu_sanitize_frame(struct trapframe *frame)
361 {
362 	frame->tf_cs = _ucodesel;
363 	frame->tf_ss = _udatasel;
364 	/* XXX VM (8086) mode not supported? */
365 	frame->tf_rflags &= (PSL_RF | PSL_USERCHANGE | PSL_VM_UNSUPP);
366 	frame->tf_rflags |= PSL_RESERVED_DEFAULT | PSL_I;
367 
368 	return(0);
369 }
370 
371 /*
372  * Sanitize the tls so loading the descriptor does not blow up
373  * on us.  For x86_64 we don't have to do anything.
374  */
375 int
376 cpu_sanitize_tls(struct savetls *tls)
377 {
378 	return(0);
379 }
380 
381 /*
382  * sigreturn(ucontext_t *sigcntxp)
383  *
384  * System call to cleanup state after a signal
385  * has been taken.  Reset signal mask and
386  * stack state from context left by sendsig (above).
387  * Return to previous pc and psl as specified by
388  * context left by sendsig. Check carefully to
389  * make sure that the user has not modified the
390  * state to gain improper privileges.
391  */
392 #define	EFL_SECURE(ef, oef)	((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
393 #define	CS_SECURE(cs)		(ISPL(cs) == SEL_UPL)
394 
395 int
396 sys_sigreturn(struct sigreturn_args *uap)
397 {
398 	struct lwp *lp = curthread->td_lwp;
399 	struct trapframe *regs;
400 	ucontext_t uc;
401 	ucontext_t *ucp;
402 	register_t rflags;
403 	int cs;
404 	int error;
405 
406 	/*
407 	 * We have to copy the information into kernel space so userland
408 	 * can't modify it while we are sniffing it.
409 	 */
410 	regs = lp->lwp_md.md_regs;
411 	error = copyin(uap->sigcntxp, &uc, sizeof(uc));
412 	if (error)
413 		return (error);
414 	ucp = &uc;
415 	rflags = ucp->uc_mcontext.mc_rflags;
416 
417 	/* VM (8086) mode not supported */
418 	rflags &= ~PSL_VM_UNSUPP;
419 
420 #if 0
421 	if (eflags & PSL_VM) {
422 		struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
423 		struct vm86_kernel *vm86;
424 
425 		/*
426 		 * if pcb_ext == 0 or vm86_inited == 0, the user hasn't
427 		 * set up the vm86 area, and we can't enter vm86 mode.
428 		 */
429 		if (lp->lwp_thread->td_pcb->pcb_ext == 0)
430 			return (EINVAL);
431 		vm86 = &lp->lwp_thread->td_pcb->pcb_ext->ext_vm86;
432 		if (vm86->vm86_inited == 0)
433 			return (EINVAL);
434 
435 		/* go back to user mode if both flags are set */
436 		if ((eflags & PSL_VIP) && (eflags & PSL_VIF))
437 			trapsignal(lp->lwp_proc, SIGBUS, 0);
438 
439 		if (vm86->vm86_has_vme) {
440 			eflags = (tf->tf_eflags & ~VME_USERCHANGE) |
441 			    (eflags & VME_USERCHANGE) | PSL_VM;
442 		} else {
443 			vm86->vm86_eflags = eflags;	/* save VIF, VIP */
444 			eflags = (tf->tf_eflags & ~VM_USERCHANGE) |					    (eflags & VM_USERCHANGE) | PSL_VM;
445 		}
446 		bcopy(&ucp.uc_mcontext.mc_gs, tf, sizeof(struct trapframe));
447 		tf->tf_eflags = eflags;
448 		tf->tf_vm86_ds = tf->tf_ds;
449 		tf->tf_vm86_es = tf->tf_es;
450 		tf->tf_vm86_fs = tf->tf_fs;
451 		tf->tf_vm86_gs = tf->tf_gs;
452 		tf->tf_ds = _udatasel;
453 		tf->tf_es = _udatasel;
454 #if 0
455 		tf->tf_fs = _udatasel;
456 		tf->tf_gs = _udatasel;
457 #endif
458 	} else
459 #endif
460 	{
461 		/*
462 		 * Don't allow users to change privileged or reserved flags.
463 		 */
464 		/*
465 		 * XXX do allow users to change the privileged flag PSL_RF.
466 		 * The cpu sets PSL_RF in tf_eflags for faults.  Debuggers
467 		 * should sometimes set it there too.  tf_eflags is kept in
468 		 * the signal context during signal handling and there is no
469 		 * other place to remember it, so the PSL_RF bit may be
470 		 * corrupted by the signal handler without us knowing.
471 		 * Corruption of the PSL_RF bit at worst causes one more or
472 		 * one less debugger trap, so allowing it is fairly harmless.
473 		 */
474 		if (!EFL_SECURE(rflags & ~PSL_RF, regs->tf_rflags & ~PSL_RF)) {
475 			kprintf("sigreturn: rflags = 0x%lx\n", (long)rflags);
476 			return(EINVAL);
477 		}
478 
479 		/*
480 		 * Don't allow users to load a valid privileged %cs.  Let the
481 		 * hardware check for invalid selectors, excess privilege in
482 		 * other selectors, invalid %eip's and invalid %esp's.
483 		 */
484 		cs = ucp->uc_mcontext.mc_cs;
485 		if (!CS_SECURE(cs)) {
486 			kprintf("sigreturn: cs = 0x%x\n", cs);
487 			trapsignal(lp, SIGBUS, T_PROTFLT);
488 			return(EINVAL);
489 		}
490 		bcopy(&ucp->uc_mcontext.mc_rdi, regs, sizeof(struct trapframe));
491 	}
492 
493 	/*
494 	 * Restore the FPU state from the frame
495 	 */
496 	npxpop(&ucp->uc_mcontext);
497 
498 	if (ucp->uc_mcontext.mc_onstack & 1)
499 		lp->lwp_sigstk.ss_flags |= SS_ONSTACK;
500 	else
501 		lp->lwp_sigstk.ss_flags &= ~SS_ONSTACK;
502 
503 	lp->lwp_sigmask = ucp->uc_sigmask;
504 	SIG_CANTMASK(lp->lwp_sigmask);
505 	return(EJUSTRETURN);
506 }
507 
508 /*
509  * cpu_idle() represents the idle LWKT.  You cannot return from this function
510  * (unless you want to blow things up!).  Instead we look for runnable threads
511  * and loop or halt as appropriate.  Giant is not held on entry to the thread.
512  *
513  * The main loop is entered with a critical section held, we must release
514  * the critical section before doing anything else.  lwkt_switch() will
515  * check for pending interrupts due to entering and exiting its own
516  * critical section.
517  *
518  * Note on cpu_idle_hlt:  On an SMP system we rely on a scheduler IPI
519  * to wake a HLTed cpu up.
520  */
521 static int	cpu_idle_hlt = 1;
522 static int	cpu_idle_hltcnt;
523 static int	cpu_idle_spincnt;
524 SYSCTL_INT(_machdep, OID_AUTO, cpu_idle_hlt, CTLFLAG_RW,
525     &cpu_idle_hlt, 0, "Idle loop HLT enable");
526 SYSCTL_INT(_machdep, OID_AUTO, cpu_idle_hltcnt, CTLFLAG_RW,
527     &cpu_idle_hltcnt, 0, "Idle loop entry halts");
528 SYSCTL_INT(_machdep, OID_AUTO, cpu_idle_spincnt, CTLFLAG_RW,
529     &cpu_idle_spincnt, 0, "Idle loop entry spins");
530 
531 void
532 cpu_idle(void)
533 {
534 	struct thread *td = curthread;
535 	struct mdglobaldata *gd = mdcpu;
536 	int reqflags;
537 
538 	crit_exit();
539 	KKASSERT(td->td_critcount == 0);
540 	cpu_enable_intr();
541 
542 	for (;;) {
543 		/*
544 		 * See if there are any LWKTs ready to go.
545 		 */
546 		lwkt_switch();
547 
548 		/*
549 		 * The idle loop halts only if no threads are scheduleable
550 		 * and no signals have occured.
551 		 */
552 		if (cpu_idle_hlt &&
553 		    (td->td_gd->gd_reqflags & RQF_IDLECHECK_WK_MASK) == 0) {
554 			splz();
555 			if ((td->td_gd->gd_reqflags & RQF_IDLECHECK_WK_MASK) == 0) {
556 #ifdef DEBUGIDLE
557 				struct timeval tv1, tv2;
558 				gettimeofday(&tv1, NULL);
559 #endif
560 				reqflags = gd->mi.gd_reqflags &
561 					   ~RQF_IDLECHECK_WK_MASK;
562 				KKASSERT(gd->mi.gd_processing_ipiq == 0);
563 				umtx_sleep(&gd->mi.gd_reqflags, reqflags,
564 					   1000000);
565 #ifdef DEBUGIDLE
566 				gettimeofday(&tv2, NULL);
567 				if (tv2.tv_usec - tv1.tv_usec +
568 				    (tv2.tv_sec - tv1.tv_sec) * 1000000
569 				    > 500000) {
570 					kprintf("cpu %d idlelock %08x %08x\n",
571 						gd->mi.gd_cpuid,
572 						gd->mi.gd_reqflags,
573 						gd->gd_fpending);
574 				}
575 #endif
576 			}
577 			++cpu_idle_hltcnt;
578 		} else {
579 			splz();
580 			__asm __volatile("pause");
581 			++cpu_idle_spincnt;
582 		}
583 	}
584 }
585 
586 /*
587  * Called by the spinlock code with or without a critical section held
588  * when a spinlock is found to be seriously constested.
589  *
590  * We need to enter a critical section to prevent signals from recursing
591  * into pthreads.
592  */
593 void
594 cpu_spinlock_contested(void)
595 {
596 	cpu_pause();
597 }
598 
599 /*
600  * Clear registers on exec
601  */
602 void
603 exec_setregs(u_long entry, u_long stack, u_long ps_strings)
604 {
605 	struct thread *td = curthread;
606 	struct lwp *lp = td->td_lwp;
607 	struct pcb *pcb = td->td_pcb;
608 	struct trapframe *regs = lp->lwp_md.md_regs;
609 
610 	/* was i386_user_cleanup() in NetBSD */
611 	user_ldt_free(pcb);
612 
613 	bzero((char *)regs, sizeof(struct trapframe));
614 	regs->tf_rip = entry;
615 	regs->tf_rsp = ((stack - 8) & ~0xFul) + 8; /* align the stack */
616 	regs->tf_rdi = stack;		/* argv */
617 	regs->tf_rflags = PSL_USER | (regs->tf_rflags & PSL_T);
618 	regs->tf_ss = _udatasel;
619 	regs->tf_cs = _ucodesel;
620 	regs->tf_rbx = ps_strings;
621 
622 	/*
623 	 * Reset the hardware debug registers if they were in use.
624 	 * They won't have any meaning for the newly exec'd process.
625 	 */
626 	if (pcb->pcb_flags & PCB_DBREGS) {
627 		pcb->pcb_dr0 = 0;
628 		pcb->pcb_dr1 = 0;
629 		pcb->pcb_dr2 = 0;
630 		pcb->pcb_dr3 = 0;
631 		pcb->pcb_dr6 = 0;
632 		pcb->pcb_dr7 = 0; /* JG set bit 10? */
633 		if (pcb == td->td_pcb) {
634 			/*
635 			 * Clear the debug registers on the running
636 			 * CPU, otherwise they will end up affecting
637 			 * the next process we switch to.
638 			 */
639 			reset_dbregs();
640 		}
641 		pcb->pcb_flags &= ~PCB_DBREGS;
642 	}
643 
644 	/*
645 	 * Initialize the math emulator (if any) for the current process.
646 	 * Actually, just clear the bit that says that the emulator has
647 	 * been initialized.  Initialization is delayed until the process
648 	 * traps to the emulator (if it is done at all) mainly because
649 	 * emulators don't provide an entry point for initialization.
650 	 */
651 	pcb->pcb_flags &= ~FP_SOFTFP;
652 
653 	/*
654 	 * NOTE: do not set CR0_TS here.  npxinit() must do it after clearing
655 	 *	 gd_npxthread.  Otherwise a preemptive interrupt thread
656 	 *	 may panic in npxdna().
657 	 */
658 	crit_enter();
659 #if 0
660 	load_cr0(rcr0() | CR0_MP);
661 #endif
662 
663 	/*
664 	 * NOTE: The MSR values must be correct so we can return to
665 	 * 	 userland.  gd_user_fs/gs must be correct so the switch
666 	 *	 code knows what the current MSR values are.
667 	 */
668 	pcb->pcb_fsbase = 0;	/* Values loaded from PCB on switch */
669 	pcb->pcb_gsbase = 0;
670 	/* Initialize the npx (if any) for the current process. */
671 	npxinit(__INITIAL_FPUCW__);
672 	crit_exit();
673 
674 	/*
675 	 * note: linux emulator needs edx to be 0x0 on entry, which is
676 	 * handled in execve simply by setting the 64 bit syscall
677 	 * return value to 0.
678 	 */
679 }
680 
681 void
682 cpu_setregs(void)
683 {
684 #if 0
685 	unsigned int cr0;
686 
687 	cr0 = rcr0();
688 	cr0 |= CR0_NE;			/* Done by npxinit() */
689 	cr0 |= CR0_MP | CR0_TS;		/* Done at every execve() too. */
690 	cr0 |= CR0_WP | CR0_AM;
691 	load_cr0(cr0);
692 	load_gs(_udatasel);
693 #endif
694 }
695 
696 static int
697 sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
698 {
699 	int error;
700 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2,
701 		req);
702 	if (!error && req->newptr)
703 		resettodr();
704 	return (error);
705 }
706 
707 SYSCTL_PROC(_machdep, CPU_ADJKERNTZ, adjkerntz, CTLTYPE_INT|CTLFLAG_RW,
708 	&adjkerntz, 0, sysctl_machdep_adjkerntz, "I", "");
709 
710 extern u_long bootdev;		/* not a cdev_t - encoding is different */
711 SYSCTL_ULONG(_machdep, OID_AUTO, guessed_bootdev,
712 	CTLFLAG_RD, &bootdev, 0, "Boot device (not in cdev_t format)");
713 
714 /*
715  * Initialize 386 and configure to run kernel
716  */
717 
718 /*
719  * Initialize segments & interrupt table
720  */
721 
722 extern  struct user *proc0paddr;
723 
724 #if 0
725 
726 extern inthand_t
727 	IDTVEC(div), IDTVEC(dbg), IDTVEC(nmi), IDTVEC(bpt), IDTVEC(ofl),
728 	IDTVEC(bnd), IDTVEC(ill), IDTVEC(dna), IDTVEC(fpusegm),
729 	IDTVEC(tss), IDTVEC(missing), IDTVEC(stk), IDTVEC(prot),
730 	IDTVEC(page), IDTVEC(mchk), IDTVEC(rsvd), IDTVEC(fpu), IDTVEC(align),
731 	IDTVEC(xmm), IDTVEC(dblfault),
732 	IDTVEC(fast_syscall), IDTVEC(fast_syscall32);
733 #endif
734 
735 #ifdef DEBUG_INTERRUPTS
736 extern inthand_t *Xrsvdary[256];
737 #endif
738 
739 int
740 ptrace_set_pc(struct lwp *lp, unsigned long addr)
741 {
742 	lp->lwp_md.md_regs->tf_rip = addr;
743 	return (0);
744 }
745 
746 int
747 ptrace_single_step(struct lwp *lp)
748 {
749 	lp->lwp_md.md_regs->tf_rflags |= PSL_T;
750 	return (0);
751 }
752 
753 int
754 fill_regs(struct lwp *lp, struct reg *regs)
755 {
756 	struct trapframe *tp;
757 
758 	if ((tp = lp->lwp_md.md_regs) == NULL)
759 		return EINVAL;
760 	bcopy(&tp->tf_rdi, &regs->r_rdi, sizeof(*regs));
761 	return (0);
762 }
763 
764 int
765 set_regs(struct lwp *lp, struct reg *regs)
766 {
767 	struct trapframe *tp;
768 
769 	tp = lp->lwp_md.md_regs;
770 	if (!EFL_SECURE(regs->r_rflags, tp->tf_rflags) ||
771 	    !CS_SECURE(regs->r_cs))
772 		return (EINVAL);
773 	bcopy(&regs->r_rdi, &tp->tf_rdi, sizeof(*regs));
774 	return (0);
775 }
776 
777 #ifndef CPU_DISABLE_SSE
778 static void
779 fill_fpregs_xmm(struct savexmm *sv_xmm, struct save87 *sv_87)
780 {
781 	struct env87 *penv_87 = &sv_87->sv_env;
782 	struct envxmm *penv_xmm = &sv_xmm->sv_env;
783 	int i;
784 
785 	/* FPU control/status */
786 	penv_87->en_cw = penv_xmm->en_cw;
787 	penv_87->en_sw = penv_xmm->en_sw;
788 	penv_87->en_tw = penv_xmm->en_tw;
789 	penv_87->en_fip = penv_xmm->en_fip;
790 	penv_87->en_fcs = penv_xmm->en_fcs;
791 	penv_87->en_opcode = penv_xmm->en_opcode;
792 	penv_87->en_foo = penv_xmm->en_foo;
793 	penv_87->en_fos = penv_xmm->en_fos;
794 
795 	/* FPU registers */
796 	for (i = 0; i < 8; ++i)
797 		sv_87->sv_ac[i] = sv_xmm->sv_fp[i].fp_acc;
798 }
799 
800 static void
801 set_fpregs_xmm(struct save87 *sv_87, struct savexmm *sv_xmm)
802 {
803 	struct env87 *penv_87 = &sv_87->sv_env;
804 	struct envxmm *penv_xmm = &sv_xmm->sv_env;
805 	int i;
806 
807 	/* FPU control/status */
808 	penv_xmm->en_cw = penv_87->en_cw;
809 	penv_xmm->en_sw = penv_87->en_sw;
810 	penv_xmm->en_tw = penv_87->en_tw;
811 	penv_xmm->en_fip = penv_87->en_fip;
812 	penv_xmm->en_fcs = penv_87->en_fcs;
813 	penv_xmm->en_opcode = penv_87->en_opcode;
814 	penv_xmm->en_foo = penv_87->en_foo;
815 	penv_xmm->en_fos = penv_87->en_fos;
816 
817 	/* FPU registers */
818 	for (i = 0; i < 8; ++i)
819 		sv_xmm->sv_fp[i].fp_acc = sv_87->sv_ac[i];
820 }
821 #endif /* CPU_DISABLE_SSE */
822 
823 int
824 fill_fpregs(struct lwp *lp, struct fpreg *fpregs)
825 {
826 	if (lp->lwp_thread == NULL || lp->lwp_thread->td_pcb == NULL)
827 		return EINVAL;
828 #ifndef CPU_DISABLE_SSE
829 	if (cpu_fxsr) {
830 		fill_fpregs_xmm(&lp->lwp_thread->td_pcb->pcb_save.sv_xmm,
831 				(struct save87 *)fpregs);
832 		return (0);
833 	}
834 #endif /* CPU_DISABLE_SSE */
835 	bcopy(&lp->lwp_thread->td_pcb->pcb_save.sv_87, fpregs, sizeof *fpregs);
836 	return (0);
837 }
838 
839 int
840 set_fpregs(struct lwp *lp, struct fpreg *fpregs)
841 {
842 #ifndef CPU_DISABLE_SSE
843 	if (cpu_fxsr) {
844 		set_fpregs_xmm((struct save87 *)fpregs,
845 			       &lp->lwp_thread->td_pcb->pcb_save.sv_xmm);
846 		return (0);
847 	}
848 #endif /* CPU_DISABLE_SSE */
849 	bcopy(fpregs, &lp->lwp_thread->td_pcb->pcb_save.sv_87, sizeof *fpregs);
850 	return (0);
851 }
852 
853 int
854 fill_dbregs(struct lwp *lp, struct dbreg *dbregs)
855 {
856 	return (ENOSYS);
857 }
858 
859 int
860 set_dbregs(struct lwp *lp, struct dbreg *dbregs)
861 {
862 	return (ENOSYS);
863 }
864 
865 #if 0
866 /*
867  * Return > 0 if a hardware breakpoint has been hit, and the
868  * breakpoint was in user space.  Return 0, otherwise.
869  */
870 int
871 user_dbreg_trap(void)
872 {
873         u_int32_t dr7, dr6; /* debug registers dr6 and dr7 */
874         u_int32_t bp;       /* breakpoint bits extracted from dr6 */
875         int nbp;            /* number of breakpoints that triggered */
876         caddr_t addr[4];    /* breakpoint addresses */
877         int i;
878 
879         dr7 = rdr7();
880         if ((dr7 & 0x000000ff) == 0) {
881                 /*
882                  * all GE and LE bits in the dr7 register are zero,
883                  * thus the trap couldn't have been caused by the
884                  * hardware debug registers
885                  */
886                 return 0;
887         }
888 
889         nbp = 0;
890         dr6 = rdr6();
891         bp = dr6 & 0x0000000f;
892 
893         if (!bp) {
894                 /*
895                  * None of the breakpoint bits are set meaning this
896                  * trap was not caused by any of the debug registers
897                  */
898                 return 0;
899         }
900 
901         /*
902          * at least one of the breakpoints were hit, check to see
903          * which ones and if any of them are user space addresses
904          */
905 
906         if (bp & 0x01) {
907                 addr[nbp++] = (caddr_t)rdr0();
908         }
909         if (bp & 0x02) {
910                 addr[nbp++] = (caddr_t)rdr1();
911         }
912         if (bp & 0x04) {
913                 addr[nbp++] = (caddr_t)rdr2();
914         }
915         if (bp & 0x08) {
916                 addr[nbp++] = (caddr_t)rdr3();
917         }
918 
919         for (i=0; i<nbp; i++) {
920                 if (addr[i] <
921                     (caddr_t)VM_MAX_USER_ADDRESS) {
922                         /*
923                          * addr[i] is in user space
924                          */
925                         return nbp;
926                 }
927         }
928 
929         /*
930          * None of the breakpoints are in user space.
931          */
932         return 0;
933 }
934 
935 #endif
936 
937 void
938 identcpu(void)
939 {
940 	int regs[4];
941 
942 	do_cpuid(1, regs);
943 	cpu_feature = regs[3];
944 }
945 
946 
947 #ifndef DDB
948 void
949 Debugger(const char *msg)
950 {
951 	kprintf("Debugger(\"%s\") called.\n", msg);
952 }
953 #endif /* no DDB */
954