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