kernel - Major signal path adjustments to fix races, tsleep race fixes, +more
[dragonfly.git] / sys / platform / vkernel / i386 / trap.c
CommitLineData
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1/*-
2 * Copyright (C) 1994, David Greenman
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * the University of Utah, and William Jolitz.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
38 * $FreeBSD: src/sys/i386/i386/trap.c,v 1.147.2.11 2003/02/27 19:09:59 luoqi Exp $
c730be20 39 * $DragonFly: src/sys/platform/vkernel/i386/trap.c,v 1.35 2008/09/09 04:06:19 dillon Exp $
6f7b98e0
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40 */
41
42/*
43 * 386 Trap and System call handling
44 */
45
46#include "use_isa.h"
47#include "use_npx.h"
48
49#include "opt_ddb.h"
50#include "opt_ktrace.h"
51
52#include <sys/param.h>
53#include <sys/systm.h>
54#include <sys/proc.h>
55#include <sys/pioctl.h>
56#include <sys/kernel.h>
57#include <sys/resourcevar.h>
58#include <sys/signalvar.h>
b1b4e5a6 59#include <sys/signal2.h>
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60#include <sys/syscall.h>
61#include <sys/sysctl.h>
62#include <sys/sysent.h>
63#include <sys/uio.h>
64#include <sys/vmmeter.h>
65#include <sys/malloc.h>
66#ifdef KTRACE
67#include <sys/ktrace.h>
68#endif
80bbc910 69#include <sys/ktr.h>
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70#include <sys/upcall.h>
71#include <sys/vkernel.h>
72#include <sys/sysproto.h>
73#include <sys/sysunion.h>
135d7199 74#include <sys/vmspace.h>
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75
76#include <vm/vm.h>
77#include <vm/vm_param.h>
78#include <sys/lock.h>
79#include <vm/pmap.h>
80#include <vm/vm_kern.h>
81#include <vm/vm_map.h>
82#include <vm/vm_page.h>
83#include <vm/vm_extern.h>
84
85#include <machine/cpu.h>
86#include <machine/md_var.h>
87#include <machine/pcb.h>
88#include <machine/smp.h>
89#include <machine/tss.h>
90#include <machine/globaldata.h>
91
92#include <machine/vm86.h>
93
94#include <ddb/ddb.h>
684a93c4 95
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96#include <sys/msgport2.h>
97#include <sys/thread2.h>
684a93c4 98#include <sys/mplock2.h>
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99
100#ifdef SMP
101
102#define MAKEMPSAFE(have_mplock) \
103 if (have_mplock == 0) { \
104 get_mplock(); \
105 have_mplock = 1; \
106 }
107
108#else
109
110#define MAKEMPSAFE(have_mplock)
111
112#endif
113
114int (*pmath_emulate) (struct trapframe *);
115
6f7b98e0 116static int trap_pfault (struct trapframe *, int, vm_offset_t);
6092278a 117static void trap_fatal (struct trapframe *, int, vm_offset_t);
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118void dblfault_handler (void);
119
120#if 0
121extern inthand_t IDTVEC(syscall);
122#endif
123
124#define MAX_TRAP_MSG 28
125static char *trap_msg[] = {
126 "", /* 0 unused */
127 "privileged instruction fault", /* 1 T_PRIVINFLT */
128 "", /* 2 unused */
129 "breakpoint instruction fault", /* 3 T_BPTFLT */
130 "", /* 4 unused */
131 "", /* 5 unused */
132 "arithmetic trap", /* 6 T_ARITHTRAP */
133 "system forced exception", /* 7 T_ASTFLT */
134 "", /* 8 unused */
135 "general protection fault", /* 9 T_PROTFLT */
136 "trace trap", /* 10 T_TRCTRAP */
137 "", /* 11 unused */
138 "page fault", /* 12 T_PAGEFLT */
139 "", /* 13 unused */
140 "alignment fault", /* 14 T_ALIGNFLT */
141 "", /* 15 unused */
142 "", /* 16 unused */
143 "", /* 17 unused */
144 "integer divide fault", /* 18 T_DIVIDE */
145 "non-maskable interrupt trap", /* 19 T_NMI */
146 "overflow trap", /* 20 T_OFLOW */
147 "FPU bounds check fault", /* 21 T_BOUND */
148 "FPU device not available", /* 22 T_DNA */
149 "double fault", /* 23 T_DOUBLEFLT */
150 "FPU operand fetch fault", /* 24 T_FPOPFLT */
151 "invalid TSS fault", /* 25 T_TSSFLT */
152 "segment not present fault", /* 26 T_SEGNPFLT */
153 "stack fault", /* 27 T_STKFLT */
154 "machine check trap", /* 28 T_MCHK */
155};
156
157#ifdef DDB
158static int ddb_on_nmi = 1;
159SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW,
160 &ddb_on_nmi, 0, "Go to DDB on NMI");
161#endif
162static int panic_on_nmi = 1;
163SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
164 &panic_on_nmi, 0, "Panic on NMI");
165static int fast_release;
166SYSCTL_INT(_machdep, OID_AUTO, fast_release, CTLFLAG_RW,
167 &fast_release, 0, "Passive Release was optimal");
168static int slow_release;
169SYSCTL_INT(_machdep, OID_AUTO, slow_release, CTLFLAG_RW,
170 &slow_release, 0, "Passive Release was nonoptimal");
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171
172MALLOC_DEFINE(M_SYSMSG, "sysmsg", "sysmsg structure");
173extern int max_sysmsg;
174
175/*
7bd858e5 176 * Passively intercepts the thread switch function to increase
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177 * the thread priority from a user priority to a kernel priority, reducing
178 * syscall and trap overhead for the case where no switch occurs.
7bd858e5 179 *
d86a23e0 180 * Synchronizes td_ucred with p_ucred. This is used by system calls,
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MD
181 * signal handling, faults, AST traps, and anything else that enters the
182 * kernel from userland and provides the kernel with a stable read-only
183 * copy of the process ucred.
6f7b98e0 184 */
6f7b98e0 185static __inline void
d86a23e0 186userenter(struct thread *curtd, struct proc *curp)
6f7b98e0 187{
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MD
188 struct ucred *ocred;
189 struct ucred *ncred;
190
3824f392 191 curtd->td_release = lwkt_passive_release;
7bd858e5 192
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193 if (curtd->td_ucred != curp->p_ucred) {
194 ncred = crhold(curp->p_ucred);
195 ocred = curtd->td_ucred;
196 curtd->td_ucred = ncred;
7bd858e5
MD
197 if (ocred)
198 crfree(ocred);
199 }
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MD
200}
201
202/*
203 * Handle signals, upcalls, profiling, and other AST's and/or tasks that
204 * must be completed before we can return to or try to return to userland.
205 *
206 * Note that td_sticks is a 64 bit quantity, but there's no point doing 64
207 * arithmatic on the delta calculation so the absolute tick values are
208 * truncated to an integer.
209 */
210static void
211userret(struct lwp *lp, struct trapframe *frame, int sticks)
212{
213 struct proc *p = lp->lwp_proc;
214 int sig;
215
216 /*
217 * Charge system time if profiling. Note: times are in microseconds.
218 * This may do a copyout and block, so do it first even though it
219 * means some system time will be charged as user time.
220 */
4643740a 221 if (p->p_flags & P_PROFIL) {
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222 addupc_task(p, frame->tf_eip,
223 (u_int)((int)lp->lwp_thread->td_sticks - sticks));
224 }
225
226recheck:
227 /*
70d3d461
SS
228 * If the jungle wants us dead, so be it.
229 */
4643740a 230 if (lp->lwp_mpflags & LWP_MP_WEXIT) {
b5c4d81f 231 lwkt_gettoken(&p->p_token);
e3161323 232 lwp_exit(0);
b5c4d81f 233 lwkt_reltoken(&p->p_token); /* NOT REACHED */
e207d1fd 234 }
70d3d461
SS
235
236 /*
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237 * Block here if we are in a stopped state.
238 */
164b8401 239 if (p->p_stat == SSTOP) {
4643740a 240 lwkt_gettoken(&p->p_token);
9a379a4a 241 tstop();
4643740a 242 lwkt_reltoken(&p->p_token);
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243 goto recheck;
244 }
245
246 /*
898e34b3
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247 * Post any pending upcalls. If running a virtual kernel be sure
248 * to restore the virtual kernel's vmspace before posting the upcall.
6f7b98e0 249 */
4643740a 250 if (p->p_flags & (P_SIGVTALRM | P_SIGPROF | P_UPCALLPEND)) {
fc509460 251 lwkt_gettoken(&p->p_token);
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MD
252 if (p->p_flags & P_SIGVTALRM) {
253 p->p_flags &= ~P_SIGVTALRM;
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MD
254 ksignal(p, SIGVTALRM);
255 }
4643740a
MD
256 if (p->p_flags & P_SIGPROF) {
257 p->p_flags &= ~P_SIGPROF;
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258 ksignal(p, SIGPROF);
259 }
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MD
260 if (p->p_flags & P_UPCALLPEND) {
261 p->p_flags &= ~P_UPCALLPEND;
898e34b3
MD
262 postupcall(lp);
263 }
fc509460 264 lwkt_reltoken(&p->p_token);
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265 goto recheck;
266 }
267
268 /*
269 * Post any pending signals
2883d2d8
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270 *
271 * WARNING! postsig() can exit and not return.
6f7b98e0 272 */
e473f776 273 if ((sig = CURSIG_TRACE(lp)) != 0) {
fc509460 274 lwkt_gettoken(&p->p_token);
6f7b98e0 275 postsig(sig);
fc509460 276 lwkt_reltoken(&p->p_token);
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277 goto recheck;
278 }
279
280 /*
281 * block here if we are swapped out, but still process signals
282 * (such as SIGKILL). proc0 (the swapin scheduler) is already
283 * aware of our situation, we do not have to wake it up.
284 */
4643740a 285 if (p->p_flags & P_SWAPPEDOUT) {
616516c8 286 lwkt_gettoken(&p->p_token);
6f7b98e0 287 get_mplock();
4643740a 288 p->p_flags |= P_SWAPWAIT;
6f7b98e0 289 swapin_request();
4643740a 290 if (p->p_flags & P_SWAPWAIT)
6f7b98e0 291 tsleep(p, PCATCH, "SWOUT", 0);
4643740a 292 p->p_flags &= ~P_SWAPWAIT;
6f7b98e0 293 rel_mplock();
616516c8 294 lwkt_reltoken(&p->p_token);
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295 goto recheck;
296 }
ae7cb1b5
NT
297
298 /*
299 * Make sure postsig() handled request to restore old signal mask after
300 * running signal handler.
301 */
4643740a 302 KKASSERT((lp->lwp_flags & LWP_OLDMASK) == 0);
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303}
304
305/*
306 * Cleanup from userenter and any passive release that might have occured.
307 * We must reclaim the current-process designation before we can return
308 * to usermode. We also handle both LWKT and USER reschedule requests.
309 */
310static __inline void
311userexit(struct lwp *lp)
312{
313 struct thread *td = lp->lwp_thread;
f5df782c 314 /* globaldata_t gd = td->td_gd; */
6f7b98e0 315
6f7b98e0 316 /*
b9eb1c19
MD
317 * Handle stop requests at kernel priority. Any requests queued
318 * after this loop will generate another AST.
6f7b98e0 319 */
b9eb1c19 320 while (lp->lwp_proc->p_stat == SSTOP) {
4643740a 321 lwkt_gettoken(&lp->lwp_proc->p_token);
b9eb1c19 322 tstop();
4643740a 323 lwkt_reltoken(&lp->lwp_proc->p_token);
fede0c7f
NT
324 }
325
6f7b98e0 326 /*
6f7b98e0
MD
327 * Reduce our priority in preparation for a return to userland. If
328 * our passive release function was still in place, our priority was
329 * never raised and does not need to be reduced.
330 */
3824f392 331 lwkt_passive_recover(td);
6f7b98e0 332
b9eb1c19
MD
333 /*
334 * Become the current user scheduled process if we aren't already,
335 * and deal with reschedule requests and other factors.
336 */
337 lp->lwp_proc->p_usched->acquire_curproc(lp);
338 /* WARNING: we may have migrated cpu's */
339 /* gd = td->td_gd; */
340}
80bbc910
SS
341
342#if !defined(KTR_KERNENTRY)
343#define KTR_KERNENTRY KTR_ALL
344#endif
345KTR_INFO_MASTER(kernentry);
346KTR_INFO(KTR_KERNENTRY, kernentry, trap, 0, "pid=%d, tid=%d, trapno=%d, eva=%p",
347 sizeof(int) + sizeof(int) + sizeof(int) + sizeof(vm_offset_t));
348KTR_INFO(KTR_KERNENTRY, kernentry, trap_ret, 0, "pid=%d, tid=%d",
349 sizeof(int) + sizeof(int));
350KTR_INFO(KTR_KERNENTRY, kernentry, syscall, 0, "pid=%d, tid=%d, call=%d",
351 sizeof(int) + sizeof(int) + sizeof(int));
352KTR_INFO(KTR_KERNENTRY, kernentry, syscall_ret, 0, "pid=%d, tid=%d, err=%d",
353 sizeof(int) + sizeof(int) + sizeof(int));
354KTR_INFO(KTR_KERNENTRY, kernentry, fork_ret, 0, "pid=%d, tid=%d",
355 sizeof(int) + sizeof(int));
356
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MD
357/*
358 * Exception, fault, and trap interface to the kernel.
359 * This common code is called from assembly language IDT gate entry
360 * routines that prepare a suitable stack frame, and restore this
361 * frame after the exception has been processed.
362 *
363 * This function is also called from doreti in an interlock to handle ASTs.
364 * For example: hardwareint->INTROUTINE->(set ast)->doreti->trap
365 *
366 * NOTE! We have to retrieve the fault address prior to obtaining the
367 * MP lock because get_mplock() may switch out. YYY cr2 really ought
368 * to be retrieved by the assembly code, not here.
369 *
370 * XXX gd_trap_nesting_level currently prevents lwkt_switch() from panicing
371 * if an attempt is made to switch from a fast interrupt or IPI. This is
372 * necessary to properly take fatal kernel traps on SMP machines if
373 * get_mplock() has to block.
374 */
375
376void
6092278a 377user_trap(struct trapframe *frame)
6f7b98e0
MD
378{
379 struct globaldata *gd = mycpu;
380 struct thread *td = gd->gd_curthread;
381 struct lwp *lp = td->td_lwp;
382 struct proc *p;
383 int sticks = 0;
384 int i = 0, ucode = 0, type, code;
385#ifdef SMP
386 int have_mplock = 0;
387#endif
388#ifdef INVARIANTS
f9235b6d 389 int crit_count = td->td_critcount;
3933a3ab 390 lwkt_tokref_t curstop = td->td_toks_stop;
6f7b98e0
MD
391#endif
392 vm_offset_t eva;
393
394 p = td->td_proc;
135d7199
MD
395
396 /*
397 * This is a bad kludge to avoid changing the various trapframe
398 * structures. Because we are enabled as a virtual kernel,
399 * the original tf_err field will be passed to us shifted 16
400 * over in the tf_trapno field for T_PAGEFLT.
401 */
4e7c41c5 402 if (frame->tf_trapno == T_PAGEFLT)
135d7199 403 eva = frame->tf_err;
4e7c41c5 404 else
135d7199 405 eva = 0;
4e7c41c5
MD
406#if 0
407 kprintf("USER_TRAP AT %08x xflags %d trapno %d eva %08x\n",
408 frame->tf_eip, frame->tf_xflags, frame->tf_trapno, eva);
409#endif
135d7199
MD
410
411 /*
412 * Everything coming from user mode runs through user_trap,
413 * including system calls.
414 */
415 if (frame->tf_trapno == T_SYSCALL80) {
416 syscall2(frame);
417 return;
418 }
419
80bbc910
SS
420 KTR_LOG(kernentry_trap, lp->lwp_proc->p_pid, lp->lwp_tid,
421 frame->tf_trapno, eva);
422
6f7b98e0
MD
423#ifdef DDB
424 if (db_active) {
6092278a 425 eva = (frame->tf_trapno == T_PAGEFLT ? rcr2() : 0);
6f7b98e0
MD
426 ++gd->gd_trap_nesting_level;
427 MAKEMPSAFE(have_mplock);
6092278a 428 trap_fatal(frame, TRUE, eva);
6f7b98e0
MD
429 --gd->gd_trap_nesting_level;
430 goto out2;
431 }
432#endif
433
6f7b98e0
MD
434#if defined(I586_CPU) && !defined(NO_F00F_HACK)
435restart:
436#endif
6092278a
MD
437 type = frame->tf_trapno;
438 code = frame->tf_err;
6f7b98e0 439
d86a23e0 440 userenter(td, p);
6f7b98e0 441
6092278a
MD
442 sticks = (int)td->td_sticks;
443 lp->lwp_md.md_regs = frame;
6f7b98e0 444
6092278a
MD
445 switch (type) {
446 case T_PRIVINFLT: /* privileged instruction fault */
f2642d5a 447 ucode = ILL_PRVOPC;
6092278a
MD
448 i = SIGILL;
449 break;
6f7b98e0 450
6092278a
MD
451 case T_BPTFLT: /* bpt instruction fault */
452 case T_TRCTRAP: /* trace trap */
453 frame->tf_eflags &= ~PSL_T;
f2642d5a 454 ucode = TRAP_TRACE;
6092278a
MD
455 i = SIGTRAP;
456 break;
6f7b98e0 457
6092278a
MD
458 case T_ARITHTRAP: /* arithmetic trap */
459 ucode = code;
460 i = SIGFPE;
461 break;
6f7b98e0 462
6092278a
MD
463 case T_ASTFLT: /* Allow process switch */
464 mycpu->gd_cnt.v_soft++;
465 if (mycpu->gd_reqflags & RQF_AST_OWEUPC) {
2a418930 466 atomic_clear_int(&mycpu->gd_reqflags,
6092278a
MD
467 RQF_AST_OWEUPC);
468 addupc_task(p, p->p_prof.pr_addr,
469 p->p_prof.pr_ticks);
470 }
471 goto out;
6f7b98e0 472
6092278a
MD
473 /*
474 * The following two traps can happen in
475 * vm86 mode, and, if so, we want to handle
476 * them specially.
477 */
478 case T_PROTFLT: /* general protection fault */
479 case T_STKFLT: /* stack fault */
6f7b98e0 480#if 0
6092278a
MD
481 if (frame->tf_eflags & PSL_VM) {
482 i = vm86_emulate((struct vm86frame *)frame);
483 if (i == 0)
484 goto out;
6f7b98e0 485 break;
6092278a
MD
486 }
487#endif
f2642d5a
AH
488 i = SIGBUS;
489 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR;
490 break;
6092278a 491 case T_SEGNPFLT: /* segment not present fault */
f2642d5a
AH
492 i = SIGBUS;
493 ucode = BUS_ADRERR;
494 break;
6092278a
MD
495 case T_TSSFLT: /* invalid TSS fault */
496 case T_DOUBLEFLT: /* double fault */
f2642d5a
AH
497 i = SIGBUS;
498 ucode = BUS_OBJERR;
6092278a 499 default:
f2642d5a
AH
500#if 0
501 ucode = code + BUS_SEGM_FAULT ; /* XXX: ???*/
502#endif
503 ucode = BUS_OBJERR;
6092278a
MD
504 i = SIGBUS;
505 break;
506
507 case T_PAGEFLT: /* page fault */
508 MAKEMPSAFE(have_mplock);
509 i = trap_pfault(frame, TRUE, eva);
510 if (i == -1)
511 goto out;
6f7b98e0 512#if defined(I586_CPU) && !defined(NO_F00F_HACK)
6092278a
MD
513 if (i == -2)
514 goto restart;
6f7b98e0 515#endif
6092278a
MD
516 if (i == 0)
517 goto out;
6f7b98e0 518
f2642d5a 519#if 0
6092278a 520 ucode = T_PAGEFLT;
f2642d5a
AH
521#endif
522 if (i == SIGSEGV)
523 ucode = SEGV_MAPERR;
524 else
525 ucode = BUS_ADRERR;
6092278a 526 break;
6f7b98e0 527
6092278a
MD
528 case T_DIVIDE: /* integer divide fault */
529 ucode = FPE_INTDIV;
530 i = SIGFPE;
531 break;
6f7b98e0
MD
532
533#if NISA > 0
6092278a
MD
534 case T_NMI:
535 MAKEMPSAFE(have_mplock);
536 /* machine/parity/power fail/"kitchen sink" faults */
537 if (isa_nmi(code) == 0) {
6f7b98e0 538#ifdef DDB
6092278a
MD
539 /*
540 * NMI can be hooked up to a pushbutton
541 * for debugging.
542 */
543 if (ddb_on_nmi) {
544 kprintf ("NMI ... going to debugger\n");
545 kdb_trap (type, 0, frame);
546 }
6f7b98e0 547#endif /* DDB */
6092278a
MD
548 goto out2;
549 } else if (panic_on_nmi)
550 panic("NMI indicates hardware failure");
551 break;
6f7b98e0
MD
552#endif /* NISA > 0 */
553
6092278a
MD
554 case T_OFLOW: /* integer overflow fault */
555 ucode = FPE_INTOVF;
556 i = SIGFPE;
557 break;
6f7b98e0 558
6092278a
MD
559 case T_BOUND: /* bounds check fault */
560 ucode = FPE_FLTSUB;
561 i = SIGFPE;
562 break;
6f7b98e0 563
6092278a 564 case T_DNA:
431d0fef
MD
565 /*
566 * Virtual kernel intercept - pass the DNA exception
567 * to the (emulated) virtual kernel if it asked to handle
568 * it. This occurs when the virtual kernel is holding
569 * onto the FP context for a different emulated
570 * process then the one currently running.
571 *
572 * We must still call npxdna() since we may have
573 * saved FP state that the (emulated) virtual kernel
574 * needs to hand over to a different emulated process.
575 */
39005e16 576 if (lp->lwp_vkernel && lp->lwp_vkernel->ve &&
431d0fef
MD
577 (td->td_pcb->pcb_flags & FP_VIRTFP)
578 ) {
579 npxdna(frame);
580 break;
581 }
6f7b98e0 582#if NNPX > 0
6092278a
MD
583 /*
584 * The kernel may have switched out the FP unit's
585 * state, causing the user process to take a fault
586 * when it tries to use the FP unit. Restore the
587 * state here
588 */
431d0fef 589 if (npxdna(frame))
6092278a 590 goto out;
6f7b98e0 591#endif
6092278a 592 if (!pmath_emulate) {
6f7b98e0 593 i = SIGFPE;
6092278a 594 ucode = FPE_FPU_NP_TRAP;
6f7b98e0
MD
595 break;
596 }
6092278a
MD
597 i = (*pmath_emulate)(frame);
598 if (i == 0) {
599 if (!(frame->tf_eflags & PSL_T))
6f7b98e0 600 goto out2;
6092278a
MD
601 frame->tf_eflags &= ~PSL_T;
602 i = SIGTRAP;
6f7b98e0 603 }
6092278a
MD
604 /* else ucode = emulator_only_knows() XXX */
605 break;
6f7b98e0 606
6092278a 607 case T_FPOPFLT: /* FPU operand fetch fault */
f2642d5a 608 ucode = ILL_COPROC;
6092278a
MD
609 i = SIGILL;
610 break;
611
612 case T_XMMFLT: /* SIMD floating-point exception */
613 ucode = 0; /* XXX */
614 i = SIGFPE;
615 break;
6f7b98e0
MD
616 }
617
618 /*
619 * Virtual kernel intercept - if the fault is directly related to a
620 * VM context managed by a virtual kernel then let the virtual kernel
621 * handle it.
622 */
39005e16 623 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
287ebb09 624 vkernel_trap(lp, frame);
6f7b98e0
MD
625 goto out;
626 }
627
628 /*
629 * Translate fault for emulators (e.g. Linux)
630 */
631 if (*p->p_sysent->sv_transtrap)
632 i = (*p->p_sysent->sv_transtrap)(i, type);
633
634 MAKEMPSAFE(have_mplock);
08f2f1bb 635 trapsignal(lp, i, ucode);
6f7b98e0
MD
636
637#ifdef DEBUG
638 if (type <= MAX_TRAP_MSG) {
639 uprintf("fatal process exception: %s",
640 trap_msg[type]);
641 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
642 uprintf(", fault VA = 0x%lx", (u_long)eva);
643 uprintf("\n");
644 }
645#endif
646
647out:
6092278a 648 userret(lp, frame, sticks);
6f7b98e0
MD
649 userexit(lp);
650out2: ;
651#ifdef SMP
652 if (have_mplock)
653 rel_mplock();
654#endif
80bbc910 655 KTR_LOG(kernentry_trap_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
6f7b98e0 656#ifdef INVARIANTS
f9235b6d 657 KASSERT(crit_count == td->td_critcount,
3933a3ab 658 ("trap: critical section count mismatch! %d/%d",
f9235b6d 659 crit_count, td->td_pri));
3933a3ab
MD
660 KASSERT(curstop == td->td_toks_stop,
661 ("trap: extra tokens held after trap! %zd/%zd",
662 curstop - &td->td_toks_base,
663 td->td_toks_stop - &td->td_toks_base));
6f7b98e0
MD
664#endif
665}
666
6092278a
MD
667void
668kern_trap(struct trapframe *frame)
6f7b98e0 669{
6092278a
MD
670 struct globaldata *gd = mycpu;
671 struct thread *td = gd->gd_curthread;
08f2f1bb 672 struct lwp *lp;
6092278a
MD
673 struct proc *p;
674 int i = 0, ucode = 0, type, code;
675#ifdef SMP
676 int have_mplock = 0;
677#endif
678#ifdef INVARIANTS
f9235b6d 679 int crit_count = td->td_critcount;
3933a3ab 680 lwkt_tokref_t curstop = td->td_toks_stop;
6092278a
MD
681#endif
682 vm_offset_t eva;
6f7b98e0 683
08f2f1bb 684 lp = td->td_lwp;
6092278a 685 p = td->td_proc;
6f7b98e0 686
4e7c41c5 687 if (frame->tf_trapno == T_PAGEFLT)
6092278a 688 eva = frame->tf_err;
4e7c41c5 689 else
135d7199 690 eva = 0;
135d7199
MD
691
692#ifdef DDB
693 if (db_active) {
694 ++gd->gd_trap_nesting_level;
695 MAKEMPSAFE(have_mplock);
696 trap_fatal(frame, FALSE, eva);
697 --gd->gd_trap_nesting_level;
698 goto out2;
699 }
700#endif
6092278a
MD
701 type = frame->tf_trapno;
702 code = frame->tf_err;
703
704#if 0
705kernel_trap:
706#endif
707 /* kernel trap */
708
709 switch (type) {
710 case T_PAGEFLT: /* page fault */
711 MAKEMPSAFE(have_mplock);
712 trap_pfault(frame, FALSE, eva);
713 goto out2;
6f7b98e0 714
6092278a
MD
715 case T_DNA:
716#if NNPX > 0
6f7b98e0 717 /*
6092278a
MD
718 * The kernel may be using npx for copying or other
719 * purposes.
6f7b98e0 720 */
431d0fef
MD
721 panic("kernel NPX should not happen");
722 if (npxdna(frame))
6092278a
MD
723 goto out2;
724#endif
725 break;
6f7b98e0 726
6092278a
MD
727 case T_PROTFLT: /* general protection fault */
728 case T_SEGNPFLT: /* segment not present fault */
6f7b98e0 729 /*
6092278a
MD
730 * Invalid segment selectors and out of bounds
731 * %eip's and %esp's can be set up in user mode.
732 * This causes a fault in kernel mode when the
733 * kernel tries to return to user mode. We want
734 * to get this fault so that we can fix the
735 * problem here and not have to check all the
736 * selectors and pointers when the user changes
737 * them.
6f7b98e0 738 */
6092278a
MD
739 if (mycpu->gd_intr_nesting_level == 0) {
740 if (td->td_pcb->pcb_onfault) {
741 frame->tf_eip =
742 (register_t)td->td_pcb->pcb_onfault;
743 goto out2;
744 }
6f7b98e0 745 }
6092278a 746 break;
6f7b98e0 747
6092278a 748 case T_TSSFLT:
6f7b98e0 749 /*
6092278a
MD
750 * PSL_NT can be set in user mode and isn't cleared
751 * automatically when the kernel is entered. This
752 * causes a TSS fault when the kernel attempts to
753 * `iret' because the TSS link is uninitialized. We
754 * want to get this fault so that we can fix the
755 * problem here and not every time the kernel is
756 * entered.
6f7b98e0 757 */
6092278a
MD
758 if (frame->tf_eflags & PSL_NT) {
759 frame->tf_eflags &= ~PSL_NT;
760 goto out2;
761 }
762 break;
6f7b98e0 763
6092278a
MD
764 case T_TRCTRAP: /* trace trap */
765#if 0
766 if (frame->tf_eip == (int)IDTVEC(syscall)) {
767 /*
768 * We've just entered system mode via the
769 * syscall lcall. Continue single stepping
770 * silently until the syscall handler has
771 * saved the flags.
772 */
773 goto out2;
774 }
775 if (frame->tf_eip == (int)IDTVEC(syscall) + 1) {
776 /*
777 * The syscall handler has now saved the
778 * flags. Stop single stepping it.
779 */
780 frame->tf_eflags &= ~PSL_T;
781 goto out2;
782 }
783#endif
784#if 0
6f7b98e0 785 /*
6092278a
MD
786 * Ignore debug register trace traps due to
787 * accesses in the user's address space, which
788 * can happen under several conditions such as
789 * if a user sets a watchpoint on a buffer and
790 * then passes that buffer to a system call.
791 * We still want to get TRCTRAPS for addresses
792 * in kernel space because that is useful when
793 * debugging the kernel.
6f7b98e0 794 */
6092278a
MD
795 if (user_dbreg_trap()) {
796 /*
797 * Reset breakpoint bits because the
798 * processor doesn't
799 */
800 load_dr6(rdr6() & 0xfffffff0);
801 goto out2;
6f7b98e0 802 }
6092278a
MD
803#endif
804 /*
805 * Fall through (TRCTRAP kernel mode, kernel address)
806 */
807 case T_BPTFLT:
808 /*
809 * If DDB is enabled, let it handle the debugger trap.
810 * Otherwise, debugger traps "can't happen".
811 */
812#ifdef DDB
813 MAKEMPSAFE(have_mplock);
814 if (kdb_trap (type, 0, frame))
815 goto out2;
816#endif
817 break;
58e0cae5
MD
818 case T_DIVIDE:
819 MAKEMPSAFE(have_mplock);
820 trap_fatal(frame, FALSE, eva);
821 goto out2;
6092278a
MD
822 case T_NMI:
823 MAKEMPSAFE(have_mplock);
824 trap_fatal(frame, FALSE, eva);
825 goto out2;
2612135b
TS
826 case T_SYSCALL80:
827 /*
828 * Ignore this trap generated from a spurious SIGTRAP.
829 *
830 * single stepping in / syscalls leads to spurious / SIGTRAP
831 * so ignore
832 *
833 * Haiku (c) 2007 Simon 'corecode' Schubert
834 */
835 goto out2;
6f7b98e0
MD
836 }
837
6092278a
MD
838 /*
839 * Translate fault for emulators (e.g. Linux)
840 */
841 if (*p->p_sysent->sv_transtrap)
842 i = (*p->p_sysent->sv_transtrap)(i, type);
6f7b98e0 843
6092278a 844 MAKEMPSAFE(have_mplock);
08f2f1bb 845 trapsignal(lp, i, ucode);
6092278a
MD
846
847#ifdef DEBUG
848 if (type <= MAX_TRAP_MSG) {
849 uprintf("fatal process exception: %s",
850 trap_msg[type]);
851 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
852 uprintf(", fault VA = 0x%lx", (u_long)eva);
853 uprintf("\n");
854 }
855#endif
856
857out2:
858 ;
859#ifdef SMP
860 if (have_mplock)
861 rel_mplock();
862#endif
863#ifdef INVARIANTS
f9235b6d 864 KASSERT(crit_count == td->td_critcount,
3933a3ab 865 ("trap: critical section count mismatch! %d/%d",
f9235b6d 866 crit_count, td->td_pri));
3933a3ab
MD
867 KASSERT(curstop == td->td_toks_stop,
868 ("trap: extra tokens held after trap! %zd/%zd",
869 curstop - &td->td_toks_base,
870 td->td_toks_stop - &td->td_toks_base));
6f7b98e0 871#endif
6092278a 872}
6f7b98e0
MD
873
874int
875trap_pfault(struct trapframe *frame, int usermode, vm_offset_t eva)
876{
877 vm_offset_t va;
878 struct vmspace *vm = NULL;
879 vm_map_t map = 0;
880 int rv = 0;
1b9d3514 881 int fault_flags;
6f7b98e0
MD
882 vm_prot_t ftype;
883 thread_t td = curthread;
287ebb09 884 struct lwp *lp = td->td_lwp;
6f7b98e0
MD
885
886 va = trunc_page(eva);
6092278a 887 if (usermode == FALSE) {
6f7b98e0 888 /*
6092278a 889 * This is a fault on kernel virtual memory.
6f7b98e0 890 */
6f7b98e0
MD
891 map = &kernel_map;
892 } else {
893 /*
894 * This is a fault on non-kernel virtual memory.
895 * vm is initialized above to NULL. If curproc is NULL
896 * or curproc->p_vmspace is NULL the fault is fatal.
897 */
287ebb09
MD
898 if (lp != NULL)
899 vm = lp->lwp_vmspace;
6f7b98e0
MD
900
901 if (vm == NULL)
902 goto nogo;
903
904 map = &vm->vm_map;
905 }
906
4e7c41c5 907 if (frame->tf_xflags & PGEX_W)
0035dca9 908 ftype = VM_PROT_READ | VM_PROT_WRITE;
6f7b98e0
MD
909 else
910 ftype = VM_PROT_READ;
911
912 if (map != &kernel_map) {
913 /*
914 * Keep swapout from messing with us during this
915 * critical time.
916 */
287ebb09 917 PHOLD(lp->lwp_proc);
6f7b98e0
MD
918
919 /*
1b9d3514
MD
920 * Issue fault
921 */
922 fault_flags = 0;
923 if (usermode)
924 fault_flags |= VM_FAULT_BURST;
925 if (ftype & VM_PROT_WRITE)
926 fault_flags |= VM_FAULT_DIRTY;
927 else
928 fault_flags |= VM_FAULT_NORMAL;
929 rv = vm_fault(map, va, ftype, fault_flags);
6f7b98e0 930
287ebb09 931 PRELE(lp->lwp_proc);
6f7b98e0
MD
932 } else {
933 /*
934 * Don't have to worry about process locking or stacks in the kernel.
935 */
936 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
937 }
938
939 if (rv == KERN_SUCCESS)
940 return (0);
941nogo:
942 if (!usermode) {
943 if (td->td_gd->gd_intr_nesting_level == 0 &&
944 td->td_pcb->pcb_onfault) {
945 frame->tf_eip = (register_t)td->td_pcb->pcb_onfault;
946 return (0);
947 }
6092278a 948 trap_fatal(frame, usermode, eva);
6f7b98e0
MD
949 return (-1);
950 }
6f7b98e0
MD
951 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
952}
953
954static void
6092278a 955trap_fatal(struct trapframe *frame, int usermode, vm_offset_t eva)
6f7b98e0
MD
956{
957 int code, type, ss, esp;
958
4e7c41c5 959 code = frame->tf_xflags;
6f7b98e0
MD
960 type = frame->tf_trapno;
961
9097944f 962 if (type <= MAX_TRAP_MSG) {
6f7b98e0
MD
963 kprintf("\n\nFatal trap %d: %s while in %s mode\n",
964 type, trap_msg[type],
9097944f
MD
965 (usermode ? "user" : "kernel"));
966 }
6f7b98e0 967#ifdef SMP
6a8aa90e 968 /* two separate prints in case of a trap on an unmapped page */
39005e16 969 kprintf("cpuid = %d\n", mycpu->gd_cpuid);
6f7b98e0
MD
970#endif
971 if (type == T_PAGEFLT) {
d557216f 972 kprintf("fault virtual address = %p\n", (void *)eva);
6f7b98e0 973 kprintf("fault code = %s %s, %s\n",
6092278a 974 usermode ? "user" : "supervisor",
6f7b98e0
MD
975 code & PGEX_W ? "write" : "read",
976 code & PGEX_P ? "protection violation" : "page not present");
977 }
978 kprintf("instruction pointer = 0x%x:0x%x\n",
979 frame->tf_cs & 0xffff, frame->tf_eip);
9097944f 980 if (usermode) {
6f7b98e0
MD
981 ss = frame->tf_ss & 0xffff;
982 esp = frame->tf_esp;
983 } else {
984 ss = GSEL(GDATA_SEL, SEL_KPL);
985 esp = (int)&frame->tf_esp;
986 }
987 kprintf("stack pointer = 0x%x:0x%x\n", ss, esp);
988 kprintf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp);
989 kprintf("processor eflags = ");
990 if (frame->tf_eflags & PSL_T)
991 kprintf("trace trap, ");
992 if (frame->tf_eflags & PSL_I)
993 kprintf("interrupt enabled, ");
994 if (frame->tf_eflags & PSL_NT)
995 kprintf("nested task, ");
996 if (frame->tf_eflags & PSL_RF)
997 kprintf("resume, ");
998#if 0
999 if (frame->tf_eflags & PSL_VM)
1000 kprintf("vm86, ");
1001#endif
1002 kprintf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12);
1003 kprintf("current process = ");
1004 if (curproc) {
1005 kprintf("%lu (%s)\n",
1006 (u_long)curproc->p_pid, curproc->p_comm ?
1007 curproc->p_comm : "");
1008 } else {
1009 kprintf("Idle\n");
1010 }
1011 kprintf("current thread = pri %d ", curthread->td_pri);
f9235b6d 1012 if (curthread->td_critcount)
6f7b98e0
MD
1013 kprintf("(CRIT)");
1014 kprintf("\n");
1015#ifdef SMP
1016/**
1017 * XXX FIXME:
1018 * we probably SHOULD have stopped the other CPUs before now!
1019 * another CPU COULD have been touching cpl at this moment...
1020 */
1021 kprintf(" <- SMP: XXX");
1022#endif
1023 kprintf("\n");
1024
1025#ifdef KDB
1026 if (kdb_trap(&psl))
1027 return;
1028#endif
1029#ifdef DDB
1030 if ((debugger_on_panic || db_active) && kdb_trap(type, code, frame))
1031 return;
1032#endif
1033 kprintf("trap number = %d\n", type);
1034 if (type <= MAX_TRAP_MSG)
1035 panic("%s", trap_msg[type]);
1036 else
1037 panic("unknown/reserved trap");
1038}
1039
1040/*
1041 * Double fault handler. Called when a fault occurs while writing
1042 * a frame for a trap/exception onto the stack. This usually occurs
1043 * when the stack overflows (such is the case with infinite recursion,
1044 * for example).
1045 *
1046 * XXX Note that the current PTD gets replaced by IdlePTD when the
1047 * task switch occurs. This means that the stack that was active at
1048 * the time of the double fault is not available at <kstack> unless
1049 * the machine was idle when the double fault occurred. The downside
1050 * of this is that "trace <ebp>" in ddb won't work.
1051 */
1052void
1053dblfault_handler(void)
1054{
1055 struct mdglobaldata *gd = mdcpu;
1056
1057 kprintf("\nFatal double fault:\n");
1058 kprintf("eip = 0x%x\n", gd->gd_common_tss.tss_eip);
1059 kprintf("esp = 0x%x\n", gd->gd_common_tss.tss_esp);
1060 kprintf("ebp = 0x%x\n", gd->gd_common_tss.tss_ebp);
1061#ifdef SMP
6a8aa90e 1062 /* two separate prints in case of a trap on an unmapped page */
39005e16 1063 kprintf("cpuid = %d\n", mycpu->gd_cpuid);
6f7b98e0
MD
1064#endif
1065 panic("double fault");
1066}
1067
1068/*
7bd858e5 1069 * syscall2 - MP aware system call request C handler
6f7b98e0 1070 *
7bd858e5
MD
1071 * A system call is essentially treated as a trap except that the
1072 * MP lock is not held on entry or return. We are responsible for
1073 * obtaining the MP lock if necessary and for handling ASTs
1074 * (e.g. a task switch) prior to return.
6f7b98e0 1075 *
7bd858e5 1076 * MPSAFE
6f7b98e0 1077 */
6f7b98e0 1078void
6092278a 1079syscall2(struct trapframe *frame)
6f7b98e0
MD
1080{
1081 struct thread *td = curthread;
1082 struct proc *p = td->td_proc;
1083 struct lwp *lp = td->td_lwp;
1084 caddr_t params;
1085 struct sysent *callp;
1086 register_t orig_tf_eflags;
1087 int sticks;
1088 int error;
1089 int narg;
1090#ifdef INVARIANTS
f9235b6d 1091 int crit_count = td->td_critcount;
6f7b98e0
MD
1092#endif
1093#ifdef SMP
1094 int have_mplock = 0;
1095#endif
1096 u_int code;
1097 union sysunion args;
1098
80bbc910
SS
1099 KTR_LOG(kernentry_syscall, lp->lwp_proc->p_pid, lp->lwp_tid,
1100 frame->tf_eax);
1101
d86a23e0 1102 userenter(td, p); /* lazy raise our priority */
6f7b98e0
MD
1103
1104 /*
1105 * Misc
1106 */
1107 sticks = (int)td->td_sticks;
6092278a 1108 orig_tf_eflags = frame->tf_eflags;
6f7b98e0
MD
1109
1110 /*
1111 * Virtual kernel intercept - if a VM context managed by a virtual
1112 * kernel issues a system call the virtual kernel handles it, not us.
1113 * Restore the virtual kernel context and return from its system
1114 * call. The current frame is copied out to the virtual kernel.
1115 */
39005e16 1116 if (lp->lwp_vkernel && lp->lwp_vkernel->ve) {
bb47c072 1117 vkernel_trap(lp, frame);
6f7b98e0
MD
1118 error = EJUSTRETURN;
1119 goto out;
1120 }
1121
1122 /*
1123 * Get the system call parameters and account for time
1124 */
6092278a
MD
1125 lp->lwp_md.md_regs = frame;
1126 params = (caddr_t)frame->tf_esp + sizeof(int);
1127 code = frame->tf_eax;
6f7b98e0
MD
1128
1129 if (p->p_sysent->sv_prepsyscall) {
1130 (*p->p_sysent->sv_prepsyscall)(
6092278a 1131 frame, (int *)(&args.nosys.sysmsg + 1),
6f7b98e0
MD
1132 &code, &params);
1133 } else {
1134 /*
1135 * Need to check if this is a 32 bit or 64 bit syscall.
1136 * fuword is MP aware.
1137 */
1138 if (code == SYS_syscall) {
1139 /*
1140 * Code is first argument, followed by actual args.
1141 */
1142 code = fuword(params);
1143 params += sizeof(int);
1144 } else if (code == SYS___syscall) {
1145 /*
1146 * Like syscall, but code is a quad, so as to maintain
1147 * quad alignment for the rest of the arguments.
1148 */
1149 code = fuword(params);
1150 params += sizeof(quad_t);
1151 }
1152 }
1153
1154 code &= p->p_sysent->sv_mask;
1155 if (code >= p->p_sysent->sv_size)
1156 callp = &p->p_sysent->sv_table[0];
1157 else
1158 callp = &p->p_sysent->sv_table[code];
1159
1160 narg = callp->sy_narg & SYF_ARGMASK;
1161
1162 /*
1163 * copyin is MP aware, but the tracing code is not
1164 */
1165 if (narg && params) {
1166 error = copyin(params, (caddr_t)(&args.nosys.sysmsg + 1),
1167 narg * sizeof(register_t));
1168 if (error) {
1169#ifdef KTRACE
1170 if (KTRPOINT(td, KTR_SYSCALL)) {
1171 MAKEMPSAFE(have_mplock);
1172
9fb04d14 1173 ktrsyscall(lp, code, narg,
6f7b98e0
MD
1174 (void *)(&args.nosys.sysmsg + 1));
1175 }
1176#endif
1177 goto bad;
1178 }
1179 }
1180
1181#ifdef KTRACE
1182 if (KTRPOINT(td, KTR_SYSCALL)) {
1183 MAKEMPSAFE(have_mplock);
9fb04d14 1184 ktrsyscall(lp, code, narg, (void *)(&args.nosys.sysmsg + 1));
6f7b98e0
MD
1185 }
1186#endif
1187
1188 /*
1189 * For traditional syscall code edx is left untouched when 32 bit
1190 * results are returned. Since edx is loaded from fds[1] when the
1191 * system call returns we pre-set it here.
1192 */
1193 args.sysmsg_fds[0] = 0;
6092278a 1194 args.sysmsg_fds[1] = frame->tf_edx;
6f7b98e0
MD
1195
1196 /*
1197 * The syscall might manipulate the trap frame. If it does it
1198 * will probably return EJUSTRETURN.
1199 */
6092278a 1200 args.sysmsg_frame = frame;
6f7b98e0
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1201
1202 STOPEVENT(p, S_SCE, narg); /* MP aware */
1203
6f7b98e0 1204 /*
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1205 * NOTE: All system calls run MPSAFE now. The system call itself
1206 * is responsible for getting the MP lock.
6f7b98e0 1207 */
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1208 error = (*callp->sy_call)(&args);
1209
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MD
1210#if 0
1211 kprintf("system call %d returned %d\n", code, error);
1212#endif
1213
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MD
1214out:
1215 /*
1216 * MP SAFE (we may or may not have the MP lock at this point)
1217 */
1218 switch (error) {
1219 case 0:
1220 /*
1221 * Reinitialize proc pointer `p' as it may be different
1222 * if this is a child returning from fork syscall.
1223 */
1224 p = curproc;
1225 lp = curthread->td_lwp;
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MD
1226 frame->tf_eax = args.sysmsg_fds[0];
1227 frame->tf_edx = args.sysmsg_fds[1];
1228 frame->tf_eflags &= ~PSL_C;
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1229 break;
1230 case ERESTART:
1231 /*
1232 * Reconstruct pc, assuming lcall $X,y is 7 bytes,
1233 * int 0x80 is 2 bytes. We saved this in tf_err.
1234 */
6092278a 1235 frame->tf_eip -= frame->tf_err;
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MD
1236 break;
1237 case EJUSTRETURN:
1238 break;
1239 case EASYNC:
1240 panic("Unexpected EASYNC return value (for now)");
1241 default:
1242bad:
1243 if (p->p_sysent->sv_errsize) {
1244 if (error >= p->p_sysent->sv_errsize)
1245 error = -1; /* XXX */
1246 else
1247 error = p->p_sysent->sv_errtbl[error];
1248 }
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MD
1249 frame->tf_eax = error;
1250 frame->tf_eflags |= PSL_C;
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1251 break;
1252 }
1253
1254 /*
1255 * Traced syscall. trapsignal() is not MP aware.
1256 */
1257 if ((orig_tf_eflags & PSL_T) /*&& !(orig_tf_eflags & PSL_VM)*/) {
1258 MAKEMPSAFE(have_mplock);
6092278a 1259 frame->tf_eflags &= ~PSL_T;
f2642d5a 1260 trapsignal(lp, SIGTRAP, TRAP_TRACE);
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MD
1261 }
1262
1263 /*
1264 * Handle reschedule and other end-of-syscall issues
1265 */
6092278a 1266 userret(lp, frame, sticks);
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MD
1267
1268#ifdef KTRACE
1269 if (KTRPOINT(td, KTR_SYSRET)) {
1270 MAKEMPSAFE(have_mplock);
9fb04d14 1271 ktrsysret(lp, code, error, args.sysmsg_result);
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MD
1272 }
1273#endif
1274
1275 /*
1276 * This works because errno is findable through the
1277 * register set. If we ever support an emulation where this
1278 * is not the case, this code will need to be revisited.
1279 */
1280 STOPEVENT(p, S_SCX, code);
1281
1282 userexit(lp);
1283#ifdef SMP
1284 /*
1285 * Release the MP lock if we had to get it
1286 */
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1287 if (have_mplock)
1288 rel_mplock();
1289#endif
80bbc910 1290 KTR_LOG(kernentry_syscall_ret, lp->lwp_proc->p_pid, lp->lwp_tid, error);
6f7b98e0 1291#ifdef INVARIANTS
f9235b6d 1292 KASSERT(crit_count == td->td_critcount,
6f7b98e0 1293 ("syscall: critical section count mismatch! %d/%d",
f9235b6d 1294 crit_count, td->td_pri));
3933a3ab
MD
1295 KASSERT(&td->td_toks_base == td->td_toks_stop,
1296 ("syscall: extra tokens held after trap! %zd",
1297 td->td_toks_stop - &td->td_toks_base));
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MD
1298#endif
1299}
1300
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MD
1301/*
1302 * NOTE: mplock not held at any point
1303 */
91bd9c1e
SS
1304void
1305fork_return(struct lwp *lp, struct trapframe *frame)
1306{
1307 frame->tf_eax = 0; /* Child returns zero */
1308 frame->tf_eflags &= ~PSL_C; /* success */
1309 frame->tf_edx = 1;
1310
1311 generic_lwp_return(lp, frame);
80bbc910 1312 KTR_LOG(kernentry_fork_ret, lp->lwp_proc->p_pid, lp->lwp_tid);
91bd9c1e
SS
1313}
1314
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MD
1315/*
1316 * Simplified back end of syscall(), used when returning from fork()
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1317 * directly into user mode.
1318 *
1319 * This code will return back into the fork trampoline code which then
1320 * runs doreti.
1321 *
1322 * NOTE: The mplock is not held at any point.
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1323 */
1324void
91bd9c1e 1325generic_lwp_return(struct lwp *lp, struct trapframe *frame)
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1326{
1327 struct proc *p = lp->lwp_proc;
1328
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MD
1329 /*
1330 * Newly forked processes are given a kernel priority. We have to
1331 * adjust the priority to a normal user priority and fake entry
1332 * into the kernel (call userenter()) to install a passive release
1333 * function just in case userret() decides to stop the process. This
1334 * can occur when ^Z races a fork. If we do not install the passive
1335 * release function the current process designation will not be
1336 * released when the thread goes to sleep.
1337 */
1338 lwkt_setpri_self(TDPRI_USER_NORM);
d86a23e0 1339 userenter(lp->lwp_thread, p);
c7eb0589 1340 userret(lp, frame, 0);
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MD
1341#ifdef KTRACE
1342 if (KTRPOINT(lp->lwp_thread, KTR_SYSRET))
9fb04d14 1343 ktrsysret(lp, SYS_fork, 0, 0);
6f7b98e0 1344#endif
4643740a 1345 lp->lwp_flags |= LWP_PASSIVE_ACQ;
6f7b98e0 1346 userexit(lp);
4643740a 1347 lp->lwp_flags &= ~LWP_PASSIVE_ACQ;
6f7b98e0 1348}
9ad680a3 1349
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MD
1350/*
1351 * doreti has turned into this. The frame is directly on the stack. We
1352 * pull everything else we need (fpu and tls context) from the current
1353 * thread.
1354 *
1355 * Note on fpu interactions: In a virtual kernel, the fpu context for
1356 * an emulated user mode process is not shared with the virtual kernel's
1357 * fpu context, so we only have to 'stack' fpu contexts within the virtual
1358 * kernel itself, and not even then since the signal() contexts that we care
1359 * about save and restore the FPU state (I think anyhow).
1360 *
1361 * vmspace_ctl() returns an error only if it had problems instaling the
1362 * context we supplied or problems copying data to/from our VM space.
1363 */
9ad680a3 1364void
c7eb0589 1365go_user(struct intrframe *frame)
9ad680a3 1366{
c7eb0589 1367 struct trapframe *tf = (void *)&frame->if_gs;
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MD
1368 int r;
1369
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1370 /*
1371 * Interrupts may be disabled on entry, make sure all signals
1372 * can be received before beginning our loop.
1373 */
1374 sigsetmask(0);
1375
1376 /*
1377 * Switch to the current simulated user process, then call
1378 * user_trap() when we break out of it (usually due to a signal).
1379 */
135d7199 1380 for (;;) {
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MD
1381 /*
1382 * Tell the real kernel whether it is ok to use the FP
1383 * unit or not.
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1384 *
1385 * The critical section is required to prevent an interrupt
1386 * from causing a preemptive task switch and changing
1387 * the FP state.
431d0fef 1388 */
eaaa6d60 1389 crit_enter();
431d0fef 1390 if (mdcpu->gd_npxthread == curthread) {
4b486183 1391 tf->tf_xflags &= ~PGEX_FPFAULT;
431d0fef 1392 } else {
4b486183 1393 tf->tf_xflags |= PGEX_FPFAULT;
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MD
1394 }
1395
1396 /*
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1397 * Run emulated user process context. This call interlocks
1398 * with new mailbox signals.
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1399 *
1400 * Set PGEX_U unconditionally, indicating a user frame (the
1401 * bit is normally set only by T_PAGEFLT).
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MD
1402 */
1403 r = vmspace_ctl(&curproc->p_vmspace->vm_pmap, VMSPACE_CTL_RUN,
1404 tf, &curthread->td_savevext);
eaaa6d60 1405 crit_exit();
c7eb0589 1406 frame->if_xflags |= PGEX_U;
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MD
1407#if 0
1408 kprintf("GO USER %d trap %d EVA %08x EIP %08x ESP %08x XFLAGS %02x/%02x\n",
1409 r, tf->tf_trapno, tf->tf_err, tf->tf_eip, tf->tf_esp,
c7eb0589 1410 tf->tf_xflags, frame->if_xflags);
4b486183 1411#endif
7c1212ec 1412 if (r < 0) {
24eb47e0 1413 if (errno != EINTR)
bb47c072 1414 panic("vmspace_ctl failed error %d", errno);
aaf8b91f 1415 } else {
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MD
1416 if (tf->tf_trapno) {
1417 user_trap(tf);
7c1212ec 1418 }
aaf8b91f 1419 }
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MD
1420 if (mycpu->gd_reqflags & RQF_AST_MASK) {
1421 tf->tf_trapno = T_ASTFLT;
1422 user_trap(tf);
1423 }
1424 tf->tf_trapno = 0;
135d7199 1425 }
9ad680a3 1426}
135d7199 1427
431d0fef 1428/*
4b486183 1429 * If PGEX_FPFAULT is set then set FP_VIRTFP in the PCB to force a T_DNA
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1430 * fault (which is then passed back to the virtual kernel) if an attempt is
1431 * made to use the FP unit.
1432 *
1433 * XXX this is a fairly big hack.
1434 */
1435void
1436set_vkernel_fp(struct trapframe *frame)
1437{
1438 struct thread *td = curthread;
1439
4b486183 1440 if (frame->tf_xflags & PGEX_FPFAULT) {
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MD
1441 td->td_pcb->pcb_flags |= FP_VIRTFP;
1442 if (mdcpu->gd_npxthread == td)
1443 npxexit();
1444 } else {
1445 td->td_pcb->pcb_flags &= ~FP_VIRTFP;
1446 }
1447}
1448
bb47c072
MD
1449/*
1450 * Called from vkernel_trap() to fixup the vkernel's syscall
1451 * frame for vmspace_ctl() return.
1452 */
1453void
1454cpu_vkernel_trap(struct trapframe *frame, int error)
1455{
1456 frame->tf_eax = error;
1457 if (error)
1458 frame->tf_eflags |= PSL_C;
1459 else
1460 frame->tf_eflags &= ~PSL_C;
1461}