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_atalk.h"
43 #include "opt_compat.h"
44 #include "opt_ddb.h"
45 #include "opt_directio.h"
46 #include "opt_inet.h"
47 #include "opt_ipx.h"
48 #include "opt_msgbuf.h"
49 #include "opt_swap.h"
50 
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/sysproto.h>
54 #include <sys/signalvar.h>
55 #include <sys/kernel.h>
56 #include <sys/linker.h>
57 #include <sys/malloc.h>
58 #include <sys/proc.h>
59 #include <sys/buf.h>
60 #include <sys/reboot.h>
61 #include <sys/mbuf.h>
62 #include <sys/msgbuf.h>
63 #include <sys/sysent.h>
64 #include <sys/sysctl.h>
65 #include <sys/vmmeter.h>
66 #include <sys/bus.h>
67 #include <sys/upcall.h>
68 #include <sys/usched.h>
69 #include <sys/reg.h>
70 
71 #include <vm/vm.h>
72 #include <vm/vm_param.h>
73 #include <sys/lock.h>
74 #include <vm/vm_kern.h>
75 #include <vm/vm_object.h>
76 #include <vm/vm_page.h>
77 #include <vm/vm_map.h>
78 #include <vm/vm_pager.h>
79 #include <vm/vm_extern.h>
80 
81 #include <sys/thread2.h>
82 #include <sys/mplock2.h>
83 
84 #include <sys/user.h>
85 #include <sys/exec.h>
86 #include <sys/cons.h>
87 
88 #include <ddb/ddb.h>
89 
90 #include <machine/cpu.h>
91 #include <machine/clock.h>
92 #include <machine/specialreg.h>
93 #include <machine/md_var.h>
94 #include <machine/pcb_ext.h>		/* pcb.h included via sys/user.h */
95 #include <machine/globaldata.h>		/* CPU_prvspace */
96 #include <machine/smp.h>
97 #ifdef PERFMON
98 #include <machine/perfmon.h>
99 #endif
100 #include <machine/cputypes.h>
101 
102 #include <bus/isa/rtc.h>
103 #include <sys/random.h>
104 #include <sys/ptrace.h>
105 #include <machine/sigframe.h>
106 #include <unistd.h>		/* umtx_* functions */
107 #include <pthread.h>		/* pthread_yield() */
108 
109 extern void dblfault_handler (void);
110 
111 #ifndef CPU_DISABLE_SSE
112 static void set_fpregs_xmm (struct save87 *, struct savexmm *);
113 static void fill_fpregs_xmm (struct savexmm *, struct save87 *);
114 #endif /* CPU_DISABLE_SSE */
115 #ifdef DIRECTIO
116 extern void ffs_rawread_setup(void);
117 #endif /* DIRECTIO */
118 
119 #ifdef SMP
120 int64_t tsc_offsets[MAXCPU];
121 #else
122 int64_t tsc_offsets[1];
123 #endif
124 
125 #if defined(SWTCH_OPTIM_STATS)
126 extern int swtch_optim_stats;
127 SYSCTL_INT(_debug, OID_AUTO, swtch_optim_stats,
128 	CTLFLAG_RD, &swtch_optim_stats, 0, "");
129 SYSCTL_INT(_debug, OID_AUTO, tlb_flush_count,
130 	CTLFLAG_RD, &tlb_flush_count, 0, "");
131 #endif
132 
133 static int
134 sysctl_hw_physmem(SYSCTL_HANDLER_ARGS)
135 {
136 	/* JG */
137 	int error = sysctl_handle_int(oidp, 0, ctob((int)Maxmem), req);
138 	return (error);
139 }
140 
141 SYSCTL_PROC(_hw, HW_PHYSMEM, physmem, CTLTYPE_INT|CTLFLAG_RD,
142 	0, 0, sysctl_hw_physmem, "IU", "");
143 
144 static int
145 sysctl_hw_usermem(SYSCTL_HANDLER_ARGS)
146 {
147 	/* JG */
148 	int error = sysctl_handle_int(oidp, 0,
149 		ctob((int)Maxmem - vmstats.v_wire_count), req);
150 	return (error);
151 }
152 
153 SYSCTL_PROC(_hw, HW_USERMEM, usermem, CTLTYPE_INT|CTLFLAG_RD,
154 	0, 0, sysctl_hw_usermem, "IU", "");
155 
156 SYSCTL_ULONG(_hw, OID_AUTO, availpages, CTLFLAG_RD, &Maxmem, 0, "");
157 
158 #if 0
159 
160 static int
161 sysctl_machdep_msgbuf(SYSCTL_HANDLER_ARGS)
162 {
163 	int error;
164 
165 	/* Unwind the buffer, so that it's linear (possibly starting with
166 	 * some initial nulls).
167 	 */
168 	error=sysctl_handle_opaque(oidp,msgbufp->msg_ptr+msgbufp->msg_bufr,
169 		msgbufp->msg_size-msgbufp->msg_bufr,req);
170 	if(error) return(error);
171 	if(msgbufp->msg_bufr>0) {
172 		error=sysctl_handle_opaque(oidp,msgbufp->msg_ptr,
173 			msgbufp->msg_bufr,req);
174 	}
175 	return(error);
176 }
177 
178 SYSCTL_PROC(_machdep, OID_AUTO, msgbuf, CTLTYPE_STRING|CTLFLAG_RD,
179 	0, 0, sysctl_machdep_msgbuf, "A","Contents of kernel message buffer");
180 
181 static int msgbuf_clear;
182 
183 static int
184 sysctl_machdep_msgbuf_clear(SYSCTL_HANDLER_ARGS)
185 {
186 	int error;
187 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2,
188 		req);
189 	if (!error && req->newptr) {
190 		/* Clear the buffer and reset write pointer */
191 		bzero(msgbufp->msg_ptr,msgbufp->msg_size);
192 		msgbufp->msg_bufr=msgbufp->msg_bufx=0;
193 		msgbuf_clear=0;
194 	}
195 	return (error);
196 }
197 
198 SYSCTL_PROC(_machdep, OID_AUTO, msgbuf_clear, CTLTYPE_INT|CTLFLAG_RW,
199 	&msgbuf_clear, 0, sysctl_machdep_msgbuf_clear, "I",
200 	"Clear kernel message buffer");
201 
202 #endif
203 
204 /*
205  * Send an interrupt to process.
206  *
207  * Stack is set up to allow sigcode stored
208  * at top to call routine, followed by kcall
209  * to sigreturn routine below.  After sigreturn
210  * resets the signal mask, the stack, and the
211  * frame pointer, it returns to the user
212  * specified pc, psl.
213  */
214 void
215 sendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
216 {
217 	struct lwp *lp = curthread->td_lwp;
218 	struct proc *p = lp->lwp_proc;
219 	struct trapframe *regs;
220 	struct sigacts *psp = p->p_sigacts;
221 	struct sigframe sf, *sfp;
222 	int oonstack;
223 	char *sp;
224 
225 	regs = lp->lwp_md.md_regs;
226 	oonstack = (lp->lwp_sigstk.ss_flags & SS_ONSTACK) ? 1 : 0;
227 
228 	/* Save user context */
229 	bzero(&sf, sizeof(struct sigframe));
230 	sf.sf_uc.uc_sigmask = *mask;
231 	sf.sf_uc.uc_stack = lp->lwp_sigstk;
232 	sf.sf_uc.uc_mcontext.mc_onstack = oonstack;
233 	KKASSERT(__offsetof(struct trapframe, tf_rdi) == 0);
234 	bcopy(regs, &sf.sf_uc.uc_mcontext.mc_rdi, sizeof(struct trapframe));
235 
236 	/* Make the size of the saved context visible to userland */
237 	sf.sf_uc.uc_mcontext.mc_len = sizeof(sf.sf_uc.uc_mcontext);
238 
239 	/* Save mailbox pending state for syscall interlock semantics */
240 	if (p->p_flag & P_MAILBOX)
241 		sf.sf_uc.uc_mcontext.mc_xflags |= PGEX_MAILBOX;
242 
243 	/* Allocate and validate space for the signal handler context. */
244         if ((lp->lwp_flag & LWP_ALTSTACK) != 0 && !oonstack &&
245 	    SIGISMEMBER(psp->ps_sigonstack, sig)) {
246 		sp = (char *)(lp->lwp_sigstk.ss_sp + lp->lwp_sigstk.ss_size -
247 			      sizeof(struct sigframe));
248 		lp->lwp_sigstk.ss_flags |= SS_ONSTACK;
249 	} else {
250 		/* We take red zone into account */
251 		sp = (char *)regs->tf_rsp - sizeof(struct sigframe) - 128;
252 	}
253 
254 	/* Align to 16 bytes */
255 	sfp = (struct sigframe *)((intptr_t)sp & ~0xFUL);
256 
257 	/* Translate the signal is appropriate */
258 	if (p->p_sysent->sv_sigtbl) {
259 		if (sig <= p->p_sysent->sv_sigsize)
260 			sig = p->p_sysent->sv_sigtbl[_SIG_IDX(sig)];
261 	}
262 
263 	/*
264 	 * Build the argument list for the signal handler.
265 	 *
266 	 * Arguments are in registers (%rdi, %rsi, %rdx, %rcx)
267 	 */
268 	regs->tf_rdi = sig;				/* argument 1 */
269 	regs->tf_rdx = (register_t)&sfp->sf_uc;		/* argument 3 */
270 
271 	if (SIGISMEMBER(psp->ps_siginfo, sig)) {
272 		/*
273 		 * Signal handler installed with SA_SIGINFO.
274 		 *
275 		 * action(signo, siginfo, ucontext)
276 		 */
277 		regs->tf_rsi = (register_t)&sfp->sf_si;	/* argument 2 */
278 		regs->tf_rcx = (register_t)regs->tf_err; /* argument 4 */
279 		sf.sf_ahu.sf_action = (__siginfohandler_t *)catcher;
280 
281 		/* fill siginfo structure */
282 		sf.sf_si.si_signo = sig;
283 		sf.sf_si.si_code = code;
284 		sf.sf_si.si_addr = (void *)regs->tf_err;
285 	} else {
286 		/*
287 		 * Old FreeBSD-style arguments.
288 		 *
289 		 * handler (signo, code, [uc], addr)
290 		 */
291 		regs->tf_rsi = (register_t)code;	/* argument 2 */
292 		regs->tf_rcx = (register_t)regs->tf_err; /* argument 4 */
293 		sf.sf_ahu.sf_handler = catcher;
294 	}
295 
296 #if 0
297 	/*
298 	 * If we're a vm86 process, we want to save the segment registers.
299 	 * We also change eflags to be our emulated eflags, not the actual
300 	 * eflags.
301 	 */
302 	if (regs->tf_eflags & PSL_VM) {
303 		struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
304 		struct vm86_kernel *vm86 = &lp->lwp_thread->td_pcb->pcb_ext->ext_vm86;
305 
306 		sf.sf_uc.uc_mcontext.mc_gs = tf->tf_vm86_gs;
307 		sf.sf_uc.uc_mcontext.mc_fs = tf->tf_vm86_fs;
308 		sf.sf_uc.uc_mcontext.mc_es = tf->tf_vm86_es;
309 		sf.sf_uc.uc_mcontext.mc_ds = tf->tf_vm86_ds;
310 
311 		if (vm86->vm86_has_vme == 0)
312 			sf.sf_uc.uc_mcontext.mc_eflags =
313 			    (tf->tf_eflags & ~(PSL_VIF | PSL_VIP)) |
314 			    (vm86->vm86_eflags & (PSL_VIF | PSL_VIP));
315 
316 		/*
317 		 * Clear PSL_NT to inhibit T_TSSFLT faults on return from
318 		 * syscalls made by the signal handler.  This just avoids
319 		 * wasting time for our lazy fixup of such faults.  PSL_NT
320 		 * does nothing in vm86 mode, but vm86 programs can set it
321 		 * almost legitimately in probes for old cpu types.
322 		 */
323 		tf->tf_eflags &= ~(PSL_VM | PSL_NT | PSL_VIF | PSL_VIP);
324 	}
325 #endif
326 
327 	/*
328 	 * Save the FPU state and reinit the FP unit
329 	 */
330 	npxpush(&sf.sf_uc.uc_mcontext);
331 
332 	/*
333 	 * Copy the sigframe out to the user's stack.
334 	 */
335 	if (copyout(&sf, sfp, sizeof(struct sigframe)) != 0) {
336 		/*
337 		 * Something is wrong with the stack pointer.
338 		 * ...Kill the process.
339 		 */
340 		sigexit(lp, SIGILL);
341 	}
342 
343 	regs->tf_rsp = (register_t)sfp;
344 	regs->tf_rip = PS_STRINGS - *(p->p_sysent->sv_szsigcode);
345 
346 	/*
347 	 * i386 abi specifies that the direction flag must be cleared
348 	 * on function entry
349 	 */
350 	regs->tf_rflags &= ~(PSL_T|PSL_D);
351 
352 	/*
353 	 * 64 bit mode has a code and stack selector but
354 	 * no data or extra selector.  %fs and %gs are not
355 	 * stored in-context.
356 	 */
357 	regs->tf_cs = _ucodesel;
358 	regs->tf_ss = _udatasel;
359 }
360 
361 /*
362  * Sanitize the trapframe for a virtual kernel passing control to a custom
363  * VM context.  Remove any items that would otherwise create a privilage
364  * issue.
365  *
366  * XXX at the moment we allow userland to set the resume flag.  Is this a
367  * bad idea?
368  */
369 int
370 cpu_sanitize_frame(struct trapframe *frame)
371 {
372 	frame->tf_cs = _ucodesel;
373 	frame->tf_ss = _udatasel;
374 	/* XXX VM (8086) mode not supported? */
375 	frame->tf_rflags &= (PSL_RF | PSL_USERCHANGE | PSL_VM_UNSUPP);
376 	frame->tf_rflags |= PSL_RESERVED_DEFAULT | PSL_I;
377 
378 	return(0);
379 }
380 
381 /*
382  * Sanitize the tls so loading the descriptor does not blow up
383  * on us.  For x86_64 we don't have to do anything.
384  */
385 int
386 cpu_sanitize_tls(struct savetls *tls)
387 {
388 	return(0);
389 }
390 
391 /*
392  * sigreturn(ucontext_t *sigcntxp)
393  *
394  * System call to cleanup state after a signal
395  * has been taken.  Reset signal mask and
396  * stack state from context left by sendsig (above).
397  * Return to previous pc and psl as specified by
398  * context left by sendsig. Check carefully to
399  * make sure that the user has not modified the
400  * state to gain improper privileges.
401  */
402 #define	EFL_SECURE(ef, oef)	((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
403 #define	CS_SECURE(cs)		(ISPL(cs) == SEL_UPL)
404 
405 int
406 sys_sigreturn(struct sigreturn_args *uap)
407 {
408 	struct lwp *lp = curthread->td_lwp;
409 	struct proc *p = lp->lwp_proc;
410 	struct trapframe *regs;
411 	ucontext_t uc;
412 	ucontext_t *ucp;
413 	register_t rflags;
414 	int cs;
415 	int error;
416 
417 	/*
418 	 * We have to copy the information into kernel space so userland
419 	 * can't modify it while we are sniffing it.
420 	 */
421 	regs = lp->lwp_md.md_regs;
422 	error = copyin(uap->sigcntxp, &uc, sizeof(uc));
423 	if (error)
424 		return (error);
425 	ucp = &uc;
426 	rflags = ucp->uc_mcontext.mc_rflags;
427 
428 	/* VM (8086) mode not supported */
429 	rflags &= ~PSL_VM_UNSUPP;
430 
431 #if 0
432 	if (eflags & PSL_VM) {
433 		struct trapframe_vm86 *tf = (struct trapframe_vm86 *)regs;
434 		struct vm86_kernel *vm86;
435 
436 		/*
437 		 * if pcb_ext == 0 or vm86_inited == 0, the user hasn't
438 		 * set up the vm86 area, and we can't enter vm86 mode.
439 		 */
440 		if (lp->lwp_thread->td_pcb->pcb_ext == 0)
441 			return (EINVAL);
442 		vm86 = &lp->lwp_thread->td_pcb->pcb_ext->ext_vm86;
443 		if (vm86->vm86_inited == 0)
444 			return (EINVAL);
445 
446 		/* go back to user mode if both flags are set */
447 		if ((eflags & PSL_VIP) && (eflags & PSL_VIF))
448 			trapsignal(lp->lwp_proc, SIGBUS, 0);
449 
450 		if (vm86->vm86_has_vme) {
451 			eflags = (tf->tf_eflags & ~VME_USERCHANGE) |
452 			    (eflags & VME_USERCHANGE) | PSL_VM;
453 		} else {
454 			vm86->vm86_eflags = eflags;	/* save VIF, VIP */
455 			eflags = (tf->tf_eflags & ~VM_USERCHANGE) |					    (eflags & VM_USERCHANGE) | PSL_VM;
456 		}
457 		bcopy(&ucp.uc_mcontext.mc_gs, tf, sizeof(struct trapframe));
458 		tf->tf_eflags = eflags;
459 		tf->tf_vm86_ds = tf->tf_ds;
460 		tf->tf_vm86_es = tf->tf_es;
461 		tf->tf_vm86_fs = tf->tf_fs;
462 		tf->tf_vm86_gs = tf->tf_gs;
463 		tf->tf_ds = _udatasel;
464 		tf->tf_es = _udatasel;
465 #if 0
466 		tf->tf_fs = _udatasel;
467 		tf->tf_gs = _udatasel;
468 #endif
469 	} else
470 #endif
471 	{
472 		/*
473 		 * Don't allow users to change privileged or reserved flags.
474 		 */
475 		/*
476 		 * XXX do allow users to change the privileged flag PSL_RF.
477 		 * The cpu sets PSL_RF in tf_eflags for faults.  Debuggers
478 		 * should sometimes set it there too.  tf_eflags is kept in
479 		 * the signal context during signal handling and there is no
480 		 * other place to remember it, so the PSL_RF bit may be
481 		 * corrupted by the signal handler without us knowing.
482 		 * Corruption of the PSL_RF bit at worst causes one more or
483 		 * one less debugger trap, so allowing it is fairly harmless.
484 		 */
485 		if (!EFL_SECURE(rflags & ~PSL_RF, regs->tf_rflags & ~PSL_RF)) {
486 			kprintf("sigreturn: rflags = 0x%lx\n", (long)rflags);
487 			return(EINVAL);
488 		}
489 
490 		/*
491 		 * Don't allow users to load a valid privileged %cs.  Let the
492 		 * hardware check for invalid selectors, excess privilege in
493 		 * other selectors, invalid %eip's and invalid %esp's.
494 		 */
495 		cs = ucp->uc_mcontext.mc_cs;
496 		if (!CS_SECURE(cs)) {
497 			kprintf("sigreturn: cs = 0x%x\n", cs);
498 			trapsignal(lp, SIGBUS, T_PROTFLT);
499 			return(EINVAL);
500 		}
501 		bcopy(&ucp->uc_mcontext.mc_rdi, regs, sizeof(struct trapframe));
502 	}
503 
504 	/*
505 	 * Restore the FPU state from the frame
506 	 */
507 	npxpop(&ucp->uc_mcontext);
508 
509 	/*
510 	 * Merge saved signal mailbox pending flag to maintain interlock
511 	 * semantics against system calls.
512 	 */
513 	if (ucp->uc_mcontext.mc_xflags & PGEX_MAILBOX)
514 		p->p_flag |= P_MAILBOX;
515 
516 	if (ucp->uc_mcontext.mc_onstack & 1)
517 		lp->lwp_sigstk.ss_flags |= SS_ONSTACK;
518 	else
519 		lp->lwp_sigstk.ss_flags &= ~SS_ONSTACK;
520 
521 	lp->lwp_sigmask = ucp->uc_sigmask;
522 	SIG_CANTMASK(lp->lwp_sigmask);
523 	return(EJUSTRETURN);
524 }
525 
526 /*
527  * Stack frame on entry to function.  %rax will contain the function vector,
528  * %rcx will contain the function data.  flags, rcx, and rax will have
529  * already been pushed on the stack.
530  */
531 struct upc_frame {
532 	register_t	rax;
533 	register_t	rcx;
534 	register_t	rdx;
535 	register_t	flags;
536 	register_t	oldip;
537 };
538 
539 void
540 sendupcall(struct vmupcall *vu, int morepending)
541 {
542 	struct lwp *lp = curthread->td_lwp;
543 	struct trapframe *regs;
544 	struct upcall upcall;
545 	struct upc_frame upc_frame;
546 	int	crit_count = 0;
547 
548 	/*
549 	 * If we are a virtual kernel running an emulated user process
550 	 * context, switch back to the virtual kernel context before
551 	 * trying to post the signal.
552 	 */
553 	if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
554 		lp->lwp_md.md_regs->tf_trapno = 0;
555 		vkernel_trap(lp, lp->lwp_md.md_regs);
556 	}
557 
558 	/*
559 	 * Get the upcall data structure
560 	 */
561 	if (copyin(lp->lwp_upcall, &upcall, sizeof(upcall)) ||
562 	    copyin((char *)upcall.upc_uthread + upcall.upc_critoff, &crit_count, sizeof(int))
563 	) {
564 		vu->vu_pending = 0;
565 		kprintf("bad upcall address\n");
566 		return;
567 	}
568 
569 	/*
570 	 * If the data structure is already marked pending or has a critical
571 	 * section count, mark the data structure as pending and return
572 	 * without doing an upcall.  vu_pending is left set.
573 	 */
574 	if (upcall.upc_pending || crit_count >= vu->vu_pending) {
575 		if (upcall.upc_pending < vu->vu_pending) {
576 			upcall.upc_pending = vu->vu_pending;
577 			copyout(&upcall.upc_pending, &lp->lwp_upcall->upc_pending,
578 				sizeof(upcall.upc_pending));
579 		}
580 		return;
581 	}
582 
583 	/*
584 	 * We can run this upcall now, clear vu_pending.
585 	 *
586 	 * Bump our critical section count and set or clear the
587 	 * user pending flag depending on whether more upcalls are
588 	 * pending.  The user will be responsible for calling
589 	 * upc_dispatch(-1) to process remaining upcalls.
590 	 */
591 	vu->vu_pending = 0;
592 	upcall.upc_pending = morepending;
593 	++crit_count;
594 	copyout(&upcall.upc_pending, &lp->lwp_upcall->upc_pending,
595 		sizeof(upcall.upc_pending));
596 	copyout(&crit_count, (char *)upcall.upc_uthread + upcall.upc_critoff,
597 		sizeof(int));
598 
599 	/*
600 	 * Construct a stack frame and issue the upcall
601 	 */
602 	regs = lp->lwp_md.md_regs;
603 	upc_frame.rax = regs->tf_rax;
604 	upc_frame.rcx = regs->tf_rcx;
605 	upc_frame.rdx = regs->tf_rdx;
606 	upc_frame.flags = regs->tf_rflags;
607 	upc_frame.oldip = regs->tf_rip;
608 	if (copyout(&upc_frame, (void *)(regs->tf_rsp - sizeof(upc_frame)),
609 	    sizeof(upc_frame)) != 0) {
610 		kprintf("bad stack on upcall\n");
611 	} else {
612 		regs->tf_rax = (register_t)vu->vu_func;
613 		regs->tf_rcx = (register_t)vu->vu_data;
614 		regs->tf_rdx = (register_t)lp->lwp_upcall;
615 		regs->tf_rip = (register_t)vu->vu_ctx;
616 		regs->tf_rsp -= sizeof(upc_frame);
617 	}
618 }
619 
620 /*
621  * fetchupcall occurs in the context of a system call, which means that
622  * we have to return EJUSTRETURN in order to prevent eax and edx from
623  * being overwritten by the syscall return value.
624  *
625  * if vu is not NULL we return the new context in %edx, the new data in %ecx,
626  * and the function pointer in %eax.
627  */
628 int
629 fetchupcall(struct vmupcall *vu, int morepending, void *rsp)
630 {
631 	struct upc_frame upc_frame;
632 	struct lwp *lp = curthread->td_lwp;
633 	struct trapframe *regs;
634 	int error;
635 	struct upcall upcall;
636 	int crit_count;
637 
638 	regs = lp->lwp_md.md_regs;
639 
640 	error = copyout(&morepending, &lp->lwp_upcall->upc_pending, sizeof(int));
641 	if (error == 0) {
642 	    if (vu) {
643 		/*
644 		 * This jumps us to the next ready context.
645 		 */
646 		vu->vu_pending = 0;
647 		error = copyin(lp->lwp_upcall, &upcall, sizeof(upcall));
648 		crit_count = 0;
649 		if (error == 0)
650 			error = copyin((char *)upcall.upc_uthread + upcall.upc_critoff, &crit_count, sizeof(int));
651 		++crit_count;
652 		if (error == 0)
653 			error = copyout(&crit_count, (char *)upcall.upc_uthread + upcall.upc_critoff, sizeof(int));
654 		regs->tf_rax = (register_t)vu->vu_func;
655 		regs->tf_rcx = (register_t)vu->vu_data;
656 		regs->tf_rdx = (register_t)lp->lwp_upcall;
657 		regs->tf_rip = (register_t)vu->vu_ctx;
658 		regs->tf_rsp = (register_t)rsp;
659 	    } else {
660 		/*
661 		 * This returns us to the originally interrupted code.
662 		 */
663 		error = copyin(rsp, &upc_frame, sizeof(upc_frame));
664 		regs->tf_rax = upc_frame.rax;
665 		regs->tf_rcx = upc_frame.rcx;
666 		regs->tf_rdx = upc_frame.rdx;
667 		regs->tf_rflags = (regs->tf_rflags & ~PSL_USERCHANGE) |
668 				(upc_frame.flags & PSL_USERCHANGE);
669 		regs->tf_rip = upc_frame.oldip;
670 		regs->tf_rsp = (register_t)((char *)rsp + sizeof(upc_frame));
671 	    }
672 	}
673 	if (error == 0)
674 		error = EJUSTRETURN;
675 	return(error);
676 }
677 
678 /*
679  * cpu_idle() represents the idle LWKT.  You cannot return from this function
680  * (unless you want to blow things up!).  Instead we look for runnable threads
681  * and loop or halt as appropriate.  Giant is not held on entry to the thread.
682  *
683  * The main loop is entered with a critical section held, we must release
684  * the critical section before doing anything else.  lwkt_switch() will
685  * check for pending interrupts due to entering and exiting its own
686  * critical section.
687  *
688  * Note on cpu_idle_hlt:  On an SMP system we rely on a scheduler IPI
689  * to wake a HLTed cpu up.  However, there are cases where the idlethread
690  * will be entered with the possibility that no IPI will occur and in such
691  * cases lwkt_switch() sets RQF_WAKEUP and we nominally check
692  * RQF_IDLECHECK_WK_MASK.
693  */
694 static int	cpu_idle_hlt = 1;
695 static int	cpu_idle_hltcnt;
696 static int	cpu_idle_spincnt;
697 SYSCTL_INT(_machdep, OID_AUTO, cpu_idle_hlt, CTLFLAG_RW,
698     &cpu_idle_hlt, 0, "Idle loop HLT enable");
699 SYSCTL_INT(_machdep, OID_AUTO, cpu_idle_hltcnt, CTLFLAG_RW,
700     &cpu_idle_hltcnt, 0, "Idle loop entry halts");
701 SYSCTL_INT(_machdep, OID_AUTO, cpu_idle_spincnt, CTLFLAG_RW,
702     &cpu_idle_spincnt, 0, "Idle loop entry spins");
703 
704 void
705 cpu_idle(void)
706 {
707 	struct thread *td = curthread;
708 	struct mdglobaldata *gd = mdcpu;
709 	int reqflags;
710 
711 	crit_exit();
712 	KKASSERT(td->td_critcount == 0);
713 	cpu_enable_intr();
714 	for (;;) {
715 		/*
716 		 * See if there are any LWKTs ready to go.
717 		 */
718 		lwkt_switch();
719 
720 		/*
721 		 * The idle loop halts only if no threads are scheduleable
722 		 * and no signals have occured.
723 		 */
724 		if (cpu_idle_hlt &&
725 		    (td->td_gd->gd_reqflags & RQF_IDLECHECK_WK_MASK) == 0) {
726 			splz();
727 			if ((td->td_gd->gd_reqflags & RQF_IDLECHECK_WK_MASK) == 0) {
728 #ifdef DEBUGIDLE
729 				struct timeval tv1, tv2;
730 				gettimeofday(&tv1, NULL);
731 #endif
732 				reqflags = gd->mi.gd_reqflags &
733 					   ~RQF_IDLECHECK_WK_MASK;
734 				umtx_sleep(&gd->mi.gd_reqflags, reqflags,
735 					   1000000);
736 #ifdef DEBUGIDLE
737 				gettimeofday(&tv2, NULL);
738 				if (tv2.tv_usec - tv1.tv_usec +
739 				    (tv2.tv_sec - tv1.tv_sec) * 1000000
740 				    > 500000) {
741 					kprintf("cpu %d idlelock %08x %08x\n",
742 						gd->mi.gd_cpuid,
743 						gd->mi.gd_reqflags,
744 						gd->gd_fpending);
745 				}
746 #endif
747 			}
748 			++cpu_idle_hltcnt;
749 		} else {
750 			splz();
751 #ifdef SMP
752 			__asm __volatile("pause");
753 #endif
754 			++cpu_idle_spincnt;
755 		}
756 	}
757 }
758 
759 #ifdef SMP
760 
761 /*
762  * Called by the spinlock code with or without a critical section held
763  * when a spinlock is found to be seriously constested.
764  *
765  * We need to enter a critical section to prevent signals from recursing
766  * into pthreads.
767  */
768 void
769 cpu_spinlock_contested(void)
770 {
771 	cpu_pause();
772 }
773 
774 #endif
775 
776 /*
777  * Clear registers on exec
778  */
779 void
780 exec_setregs(u_long entry, u_long stack, u_long ps_strings)
781 {
782 	struct thread *td = curthread;
783 	struct lwp *lp = td->td_lwp;
784 	struct pcb *pcb = td->td_pcb;
785 	struct trapframe *regs = lp->lwp_md.md_regs;
786 
787 	/* was i386_user_cleanup() in NetBSD */
788 	user_ldt_free(pcb);
789 
790 	bzero((char *)regs, sizeof(struct trapframe));
791 	regs->tf_rip = entry;
792 	regs->tf_rsp = ((stack - 8) & ~0xFul) + 8; /* align the stack */
793 	regs->tf_rdi = stack;		/* argv */
794 	regs->tf_rflags = PSL_USER | (regs->tf_rflags & PSL_T);
795 	regs->tf_ss = _udatasel;
796 	regs->tf_cs = _ucodesel;
797 	regs->tf_rbx = ps_strings;
798 
799 	/*
800 	 * Reset the hardware debug registers if they were in use.
801 	 * They won't have any meaning for the newly exec'd process.
802 	 */
803 	if (pcb->pcb_flags & PCB_DBREGS) {
804 		pcb->pcb_dr0 = 0;
805 		pcb->pcb_dr1 = 0;
806 		pcb->pcb_dr2 = 0;
807 		pcb->pcb_dr3 = 0;
808 		pcb->pcb_dr6 = 0;
809 		pcb->pcb_dr7 = 0; /* JG set bit 10? */
810 		if (pcb == td->td_pcb) {
811 			/*
812 			 * Clear the debug registers on the running
813 			 * CPU, otherwise they will end up affecting
814 			 * the next process we switch to.
815 			 */
816 			reset_dbregs();
817 		}
818 		pcb->pcb_flags &= ~PCB_DBREGS;
819 	}
820 
821 	/*
822 	 * Initialize the math emulator (if any) for the current process.
823 	 * Actually, just clear the bit that says that the emulator has
824 	 * been initialized.  Initialization is delayed until the process
825 	 * traps to the emulator (if it is done at all) mainly because
826 	 * emulators don't provide an entry point for initialization.
827 	 */
828 	pcb->pcb_flags &= ~FP_SOFTFP;
829 
830 	/*
831 	 * NOTE: do not set CR0_TS here.  npxinit() must do it after clearing
832 	 *	 gd_npxthread.  Otherwise a preemptive interrupt thread
833 	 *	 may panic in npxdna().
834 	 */
835 	crit_enter();
836 #if 0
837 	load_cr0(rcr0() | CR0_MP);
838 #endif
839 
840 	/*
841 	 * NOTE: The MSR values must be correct so we can return to
842 	 * 	 userland.  gd_user_fs/gs must be correct so the switch
843 	 *	 code knows what the current MSR values are.
844 	 */
845 	pcb->pcb_fsbase = 0;	/* Values loaded from PCB on switch */
846 	pcb->pcb_gsbase = 0;
847 	/* Initialize the npx (if any) for the current process. */
848 	npxinit(__INITIAL_NPXCW__);
849 	crit_exit();
850 
851 	/*
852 	 * note: linux emulator needs edx to be 0x0 on entry, which is
853 	 * handled in execve simply by setting the 64 bit syscall
854 	 * return value to 0.
855 	 */
856 }
857 
858 void
859 cpu_setregs(void)
860 {
861 #if 0
862 	unsigned int cr0;
863 
864 	cr0 = rcr0();
865 	cr0 |= CR0_NE;			/* Done by npxinit() */
866 	cr0 |= CR0_MP | CR0_TS;		/* Done at every execve() too. */
867 	cr0 |= CR0_WP | CR0_AM;
868 	load_cr0(cr0);
869 	load_gs(_udatasel);
870 #endif
871 }
872 
873 static int
874 sysctl_machdep_adjkerntz(SYSCTL_HANDLER_ARGS)
875 {
876 	int error;
877 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2,
878 		req);
879 	if (!error && req->newptr)
880 		resettodr();
881 	return (error);
882 }
883 
884 SYSCTL_PROC(_machdep, CPU_ADJKERNTZ, adjkerntz, CTLTYPE_INT|CTLFLAG_RW,
885 	&adjkerntz, 0, sysctl_machdep_adjkerntz, "I", "");
886 
887 extern u_long bootdev;		/* not a cdev_t - encoding is different */
888 SYSCTL_ULONG(_machdep, OID_AUTO, guessed_bootdev,
889 	CTLFLAG_RD, &bootdev, 0, "Boot device (not in cdev_t format)");
890 
891 /*
892  * Initialize 386 and configure to run kernel
893  */
894 
895 /*
896  * Initialize segments & interrupt table
897  */
898 
899 extern  struct user *proc0paddr;
900 
901 #if 0
902 
903 extern inthand_t
904 	IDTVEC(div), IDTVEC(dbg), IDTVEC(nmi), IDTVEC(bpt), IDTVEC(ofl),
905 	IDTVEC(bnd), IDTVEC(ill), IDTVEC(dna), IDTVEC(fpusegm),
906 	IDTVEC(tss), IDTVEC(missing), IDTVEC(stk), IDTVEC(prot),
907 	IDTVEC(page), IDTVEC(mchk), IDTVEC(rsvd), IDTVEC(fpu), IDTVEC(align),
908 	IDTVEC(xmm), IDTVEC(dblfault),
909 	IDTVEC(fast_syscall), IDTVEC(fast_syscall32);
910 #endif
911 
912 #ifdef DEBUG_INTERRUPTS
913 extern inthand_t *Xrsvdary[256];
914 #endif
915 
916 int
917 ptrace_set_pc(struct lwp *lp, unsigned long addr)
918 {
919 	lp->lwp_md.md_regs->tf_rip = addr;
920 	return (0);
921 }
922 
923 int
924 ptrace_single_step(struct lwp *lp)
925 {
926 	lp->lwp_md.md_regs->tf_rflags |= PSL_T;
927 	return (0);
928 }
929 
930 int
931 fill_regs(struct lwp *lp, struct reg *regs)
932 {
933 	struct trapframe *tp;
934 
935 	tp = lp->lwp_md.md_regs;
936 	bcopy(&tp->tf_rdi, &regs->r_rdi, sizeof(*regs));
937 	return (0);
938 }
939 
940 int
941 set_regs(struct lwp *lp, struct reg *regs)
942 {
943 	struct trapframe *tp;
944 
945 	tp = lp->lwp_md.md_regs;
946 	if (!EFL_SECURE(regs->r_rflags, tp->tf_rflags) ||
947 	    !CS_SECURE(regs->r_cs))
948 		return (EINVAL);
949 	bcopy(&regs->r_rdi, &tp->tf_rdi, sizeof(*regs));
950 	return (0);
951 }
952 
953 #ifndef CPU_DISABLE_SSE
954 static void
955 fill_fpregs_xmm(struct savexmm *sv_xmm, struct save87 *sv_87)
956 {
957 	struct env87 *penv_87 = &sv_87->sv_env;
958 	struct envxmm *penv_xmm = &sv_xmm->sv_env;
959 	int i;
960 
961 	/* FPU control/status */
962 	penv_87->en_cw = penv_xmm->en_cw;
963 	penv_87->en_sw = penv_xmm->en_sw;
964 	penv_87->en_tw = penv_xmm->en_tw;
965 	penv_87->en_fip = penv_xmm->en_fip;
966 	penv_87->en_fcs = penv_xmm->en_fcs;
967 	penv_87->en_opcode = penv_xmm->en_opcode;
968 	penv_87->en_foo = penv_xmm->en_foo;
969 	penv_87->en_fos = penv_xmm->en_fos;
970 
971 	/* FPU registers */
972 	for (i = 0; i < 8; ++i)
973 		sv_87->sv_ac[i] = sv_xmm->sv_fp[i].fp_acc;
974 
975 	sv_87->sv_ex_sw = sv_xmm->sv_ex_sw;
976 }
977 
978 static void
979 set_fpregs_xmm(struct save87 *sv_87, struct savexmm *sv_xmm)
980 {
981 	struct env87 *penv_87 = &sv_87->sv_env;
982 	struct envxmm *penv_xmm = &sv_xmm->sv_env;
983 	int i;
984 
985 	/* FPU control/status */
986 	penv_xmm->en_cw = penv_87->en_cw;
987 	penv_xmm->en_sw = penv_87->en_sw;
988 	penv_xmm->en_tw = penv_87->en_tw;
989 	penv_xmm->en_fip = penv_87->en_fip;
990 	penv_xmm->en_fcs = penv_87->en_fcs;
991 	penv_xmm->en_opcode = penv_87->en_opcode;
992 	penv_xmm->en_foo = penv_87->en_foo;
993 	penv_xmm->en_fos = penv_87->en_fos;
994 
995 	/* FPU registers */
996 	for (i = 0; i < 8; ++i)
997 		sv_xmm->sv_fp[i].fp_acc = sv_87->sv_ac[i];
998 
999 	sv_xmm->sv_ex_sw = sv_87->sv_ex_sw;
1000 }
1001 #endif /* CPU_DISABLE_SSE */
1002 
1003 int
1004 fill_fpregs(struct lwp *lp, struct fpreg *fpregs)
1005 {
1006 #ifndef CPU_DISABLE_SSE
1007 	if (cpu_fxsr) {
1008 		fill_fpregs_xmm(&lp->lwp_thread->td_pcb->pcb_save.sv_xmm,
1009 				(struct save87 *)fpregs);
1010 		return (0);
1011 	}
1012 #endif /* CPU_DISABLE_SSE */
1013 	bcopy(&lp->lwp_thread->td_pcb->pcb_save.sv_87, fpregs, sizeof *fpregs);
1014 	return (0);
1015 }
1016 
1017 int
1018 set_fpregs(struct lwp *lp, struct fpreg *fpregs)
1019 {
1020 #ifndef CPU_DISABLE_SSE
1021 	if (cpu_fxsr) {
1022 		set_fpregs_xmm((struct save87 *)fpregs,
1023 			       &lp->lwp_thread->td_pcb->pcb_save.sv_xmm);
1024 		return (0);
1025 	}
1026 #endif /* CPU_DISABLE_SSE */
1027 	bcopy(fpregs, &lp->lwp_thread->td_pcb->pcb_save.sv_87, sizeof *fpregs);
1028 	return (0);
1029 }
1030 
1031 int
1032 fill_dbregs(struct lwp *lp, struct dbreg *dbregs)
1033 {
1034 	return (ENOSYS);
1035 }
1036 
1037 int
1038 set_dbregs(struct lwp *lp, struct dbreg *dbregs)
1039 {
1040 	return (ENOSYS);
1041 }
1042 
1043 #if 0
1044 /*
1045  * Return > 0 if a hardware breakpoint has been hit, and the
1046  * breakpoint was in user space.  Return 0, otherwise.
1047  */
1048 int
1049 user_dbreg_trap(void)
1050 {
1051         u_int32_t dr7, dr6; /* debug registers dr6 and dr7 */
1052         u_int32_t bp;       /* breakpoint bits extracted from dr6 */
1053         int nbp;            /* number of breakpoints that triggered */
1054         caddr_t addr[4];    /* breakpoint addresses */
1055         int i;
1056 
1057         dr7 = rdr7();
1058         if ((dr7 & 0x000000ff) == 0) {
1059                 /*
1060                  * all GE and LE bits in the dr7 register are zero,
1061                  * thus the trap couldn't have been caused by the
1062                  * hardware debug registers
1063                  */
1064                 return 0;
1065         }
1066 
1067         nbp = 0;
1068         dr6 = rdr6();
1069         bp = dr6 & 0x0000000f;
1070 
1071         if (!bp) {
1072                 /*
1073                  * None of the breakpoint bits are set meaning this
1074                  * trap was not caused by any of the debug registers
1075                  */
1076                 return 0;
1077         }
1078 
1079         /*
1080          * at least one of the breakpoints were hit, check to see
1081          * which ones and if any of them are user space addresses
1082          */
1083 
1084         if (bp & 0x01) {
1085                 addr[nbp++] = (caddr_t)rdr0();
1086         }
1087         if (bp & 0x02) {
1088                 addr[nbp++] = (caddr_t)rdr1();
1089         }
1090         if (bp & 0x04) {
1091                 addr[nbp++] = (caddr_t)rdr2();
1092         }
1093         if (bp & 0x08) {
1094                 addr[nbp++] = (caddr_t)rdr3();
1095         }
1096 
1097         for (i=0; i<nbp; i++) {
1098                 if (addr[i] <
1099                     (caddr_t)VM_MAX_USER_ADDRESS) {
1100                         /*
1101                          * addr[i] is in user space
1102                          */
1103                         return nbp;
1104                 }
1105         }
1106 
1107         /*
1108          * None of the breakpoints are in user space.
1109          */
1110         return 0;
1111 }
1112 
1113 #endif
1114 
1115 void
1116 identcpu(void)
1117 {
1118 	int regs[4];
1119 
1120 	do_cpuid(1, regs);
1121 	cpu_feature = regs[3];
1122 }
1123 
1124 
1125 #ifndef DDB
1126 void
1127 Debugger(const char *msg)
1128 {
1129 	kprintf("Debugger(\"%s\") called.\n", msg);
1130 }
1131 #endif /* no DDB */
1132