FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/trap.c
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 */
39
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42
43 /*
44 * 386 Trap and System call handling
45 */
46
47 #include "opt_clock.h"
48 #include "opt_cpu.h"
49 #include "opt_hwpmc_hooks.h"
50 #include "opt_isa.h"
51 #include "opt_kdb.h"
52 #include "opt_kdtrace.h"
53 #include "opt_ktrace.h"
54 #include "opt_npx.h"
55 #include "opt_trap.h"
56
57 #include <sys/param.h>
58 #include <sys/bus.h>
59 #include <sys/systm.h>
60 #include <sys/proc.h>
61 #include <sys/pioctl.h>
62 #include <sys/ptrace.h>
63 #include <sys/kdb.h>
64 #include <sys/kernel.h>
65 #include <sys/ktr.h>
66 #include <sys/lock.h>
67 #include <sys/mutex.h>
68 #include <sys/resourcevar.h>
69 #include <sys/signalvar.h>
70 #include <sys/syscall.h>
71 #include <sys/sysctl.h>
72 #include <sys/sysent.h>
73 #include <sys/uio.h>
74 #include <sys/vmmeter.h>
75 #ifdef KTRACE
76 #include <sys/ktrace.h>
77 #endif
78 #ifdef HWPMC_HOOKS
79 #include <sys/pmckern.h>
80 #endif
81 #include <security/audit/audit.h>
82
83 #include <vm/vm.h>
84 #include <vm/vm_param.h>
85 #include <vm/pmap.h>
86 #include <vm/vm_kern.h>
87 #include <vm/vm_map.h>
88 #include <vm/vm_page.h>
89 #include <vm/vm_extern.h>
90
91 #include <machine/cpu.h>
92 #include <machine/intr_machdep.h>
93 #include <machine/mca.h>
94 #include <machine/md_var.h>
95 #include <machine/pcb.h>
96 #ifdef SMP
97 #include <machine/smp.h>
98 #endif
99 #include <machine/tss.h>
100 #include <machine/vm86.h>
101
102 #ifdef POWERFAIL_NMI
103 #include <sys/syslog.h>
104 #include <machine/clock.h>
105 #endif
106
107 #ifdef KDTRACE_HOOKS
108 #include <sys/dtrace_bsd.h>
109
110 /*
111 * This is a hook which is initialised by the dtrace module
112 * to handle traps which might occur during DTrace probe
113 * execution.
114 */
115 dtrace_trap_func_t dtrace_trap_func;
116
117 dtrace_doubletrap_func_t dtrace_doubletrap_func;
118
119 /*
120 * This is a hook which is initialised by the systrace module
121 * when it is loaded. This keeps the DTrace syscall provider
122 * implementation opaque.
123 */
124 systrace_probe_func_t systrace_probe_func;
125 #endif
126
127 /* Defined in i386/i386/elf_machdep.c. */
128 extern struct sysentvec elf32_freebsd_sysvec;
129
130 extern void trap(struct trapframe *frame);
131 extern void syscall(struct trapframe *frame);
132
133 static int trap_pfault(struct trapframe *, int, vm_offset_t);
134 static void trap_fatal(struct trapframe *, vm_offset_t);
135 void dblfault_handler(void);
136
137 extern inthand_t IDTVEC(lcall_syscall);
138
139 #define MAX_TRAP_MSG 30
140 static char *trap_msg[] = {
141 "", /* 0 unused */
142 "privileged instruction fault", /* 1 T_PRIVINFLT */
143 "", /* 2 unused */
144 "breakpoint instruction fault", /* 3 T_BPTFLT */
145 "", /* 4 unused */
146 "", /* 5 unused */
147 "arithmetic trap", /* 6 T_ARITHTRAP */
148 "", /* 7 unused */
149 "", /* 8 unused */
150 "general protection fault", /* 9 T_PROTFLT */
151 "trace trap", /* 10 T_TRCTRAP */
152 "", /* 11 unused */
153 "page fault", /* 12 T_PAGEFLT */
154 "", /* 13 unused */
155 "alignment fault", /* 14 T_ALIGNFLT */
156 "", /* 15 unused */
157 "", /* 16 unused */
158 "", /* 17 unused */
159 "integer divide fault", /* 18 T_DIVIDE */
160 "non-maskable interrupt trap", /* 19 T_NMI */
161 "overflow trap", /* 20 T_OFLOW */
162 "FPU bounds check fault", /* 21 T_BOUND */
163 "FPU device not available", /* 22 T_DNA */
164 "double fault", /* 23 T_DOUBLEFLT */
165 "FPU operand fetch fault", /* 24 T_FPOPFLT */
166 "invalid TSS fault", /* 25 T_TSSFLT */
167 "segment not present fault", /* 26 T_SEGNPFLT */
168 "stack fault", /* 27 T_STKFLT */
169 "machine check trap", /* 28 T_MCHK */
170 "SIMD floating-point exception", /* 29 T_XMMFLT */
171 "reserved (unknown) fault", /* 30 T_RESERVED */
172 };
173
174 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
175 extern int has_f00f_bug;
176 #endif
177
178 #ifdef KDB
179 static int kdb_on_nmi = 1;
180 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW,
181 &kdb_on_nmi, 0, "Go to KDB on NMI");
182 #endif
183 static int panic_on_nmi = 1;
184 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
185 &panic_on_nmi, 0, "Panic on NMI");
186 static int prot_fault_translation = 0;
187 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW,
188 &prot_fault_translation, 0, "Select signal to deliver on protection fault");
189
190 extern char *syscallnames[];
191
192 /*
193 * Exception, fault, and trap interface to the FreeBSD kernel.
194 * This common code is called from assembly language IDT gate entry
195 * routines that prepare a suitable stack frame, and restore this
196 * frame after the exception has been processed.
197 */
198
199 void
200 trap(struct trapframe *frame)
201 {
202 struct thread *td = curthread;
203 struct proc *p = td->td_proc;
204 int i = 0, ucode = 0, code;
205 u_int type;
206 register_t addr = 0;
207 vm_offset_t eva;
208 ksiginfo_t ksi;
209 #ifdef POWERFAIL_NMI
210 static int lastalert = 0;
211 #endif
212
213 PCPU_INC(cnt.v_trap);
214 type = frame->tf_trapno;
215
216 #ifdef SMP
217 #ifdef STOP_NMI
218 /* Handler for NMI IPIs used for stopping CPUs. */
219 if (type == T_NMI) {
220 if (ipi_nmi_handler() == 0)
221 goto out;
222 }
223 #endif /* STOP_NMI */
224 #endif /* SMP */
225
226 #ifdef KDB
227 if (kdb_active) {
228 kdb_reenter();
229 goto out;
230 }
231 #endif
232
233 #ifdef HWPMC_HOOKS
234 /*
235 * CPU PMCs interrupt using an NMI so we check for that first.
236 * If the HWPMC module is active, 'pmc_hook' will point to
237 * the function to be called. A return value of '1' from the
238 * hook means that the NMI was handled by it and that we can
239 * return immediately.
240 */
241 if (type == T_NMI && pmc_intr &&
242 (*pmc_intr)(PCPU_GET(cpuid), frame))
243 goto out;
244 #endif
245
246 if (type == T_MCHK) {
247 if (!mca_intr())
248 trap_fatal(frame, 0);
249 goto out;
250 }
251
252 #ifdef KDTRACE_HOOKS
253 /*
254 * A trap can occur while DTrace executes a probe. Before
255 * executing the probe, DTrace blocks re-scheduling and sets
256 * a flag in it's per-cpu flags to indicate that it doesn't
257 * want to fault. On returning from the probe, the no-fault
258 * flag is cleared and finally re-scheduling is enabled.
259 *
260 * If the DTrace kernel module has registered a trap handler,
261 * call it and if it returns non-zero, assume that it has
262 * handled the trap and modified the trap frame so that this
263 * function can return normally.
264 */
265 if ((type == T_PROTFLT || type == T_PAGEFLT) &&
266 dtrace_trap_func != NULL)
267 if ((*dtrace_trap_func)(frame, type))
268 goto out;
269 #endif
270
271 if ((frame->tf_eflags & PSL_I) == 0) {
272 /*
273 * Buggy application or kernel code has disabled
274 * interrupts and then trapped. Enabling interrupts
275 * now is wrong, but it is better than running with
276 * interrupts disabled until they are accidentally
277 * enabled later.
278 */
279 if (ISPL(frame->tf_cs) == SEL_UPL || (frame->tf_eflags & PSL_VM))
280 printf(
281 "pid %ld (%s): trap %d with interrupts disabled\n",
282 (long)curproc->p_pid, curproc->p_comm, type);
283 else if (type != T_BPTFLT && type != T_TRCTRAP &&
284 frame->tf_eip != (int)cpu_switch_load_gs) {
285 /*
286 * XXX not quite right, since this may be for a
287 * multiple fault in user mode.
288 */
289 printf("kernel trap %d with interrupts disabled\n",
290 type);
291 /*
292 * Page faults need interrupts disabled until later,
293 * and we shouldn't enable interrupts while holding
294 * a spin lock or if servicing an NMI.
295 */
296 if (type != T_NMI && type != T_PAGEFLT &&
297 td->td_md.md_spinlock_count == 0)
298 enable_intr();
299 }
300 }
301
302 eva = 0;
303 code = frame->tf_err;
304 if (type == T_PAGEFLT) {
305 /*
306 * For some Cyrix CPUs, %cr2 is clobbered by
307 * interrupts. This problem is worked around by using
308 * an interrupt gate for the pagefault handler. We
309 * are finally ready to read %cr2 and then must
310 * reenable interrupts.
311 *
312 * If we get a page fault while in a critical section, then
313 * it is most likely a fatal kernel page fault. The kernel
314 * is already going to panic trying to get a sleep lock to
315 * do the VM lookup, so just consider it a fatal trap so the
316 * kernel can print out a useful trap message and even get
317 * to the debugger.
318 *
319 * If we get a page fault while holding a non-sleepable
320 * lock, then it is most likely a fatal kernel page fault.
321 * If WITNESS is enabled, then it's going to whine about
322 * bogus LORs with various VM locks, so just skip to the
323 * fatal trap handling directly.
324 */
325 eva = rcr2();
326 if (td->td_critnest != 0 ||
327 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL,
328 "Kernel page fault") != 0)
329 trap_fatal(frame, eva);
330 else
331 enable_intr();
332 }
333
334 if ((ISPL(frame->tf_cs) == SEL_UPL) ||
335 ((frame->tf_eflags & PSL_VM) &&
336 !(PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL))) {
337 /* user trap */
338
339 td->td_pticks = 0;
340 td->td_frame = frame;
341 addr = frame->tf_eip;
342 if (td->td_ucred != p->p_ucred)
343 cred_update_thread(td);
344
345 switch (type) {
346 case T_PRIVINFLT: /* privileged instruction fault */
347 i = SIGILL;
348 ucode = ILL_PRVOPC;
349 break;
350
351 case T_BPTFLT: /* bpt instruction fault */
352 case T_TRCTRAP: /* trace trap */
353 enable_intr();
354 frame->tf_eflags &= ~PSL_T;
355 i = SIGTRAP;
356 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
357 break;
358
359 case T_ARITHTRAP: /* arithmetic trap */
360 #ifdef DEV_NPX
361 ucode = npxtrap();
362 if (ucode == -1)
363 goto userout;
364 #else
365 ucode = 0;
366 #endif
367 i = SIGFPE;
368 break;
369
370 /*
371 * The following two traps can happen in
372 * vm86 mode, and, if so, we want to handle
373 * them specially.
374 */
375 case T_PROTFLT: /* general protection fault */
376 case T_STKFLT: /* stack fault */
377 if (frame->tf_eflags & PSL_VM) {
378 i = vm86_emulate((struct vm86frame *)frame);
379 if (i == 0)
380 goto user;
381 break;
382 }
383 i = SIGBUS;
384 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR;
385 break;
386 case T_SEGNPFLT: /* segment not present fault */
387 i = SIGBUS;
388 ucode = BUS_ADRERR;
389 break;
390 case T_TSSFLT: /* invalid TSS fault */
391 i = SIGBUS;
392 ucode = BUS_OBJERR;
393 break;
394 case T_DOUBLEFLT: /* double fault */
395 default:
396 i = SIGBUS;
397 ucode = BUS_OBJERR;
398 break;
399
400 case T_PAGEFLT: /* page fault */
401 #ifdef KSE
402 if (td->td_pflags & TDP_SA)
403 thread_user_enter(td);
404 #endif
405
406 i = trap_pfault(frame, TRUE, eva);
407 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
408 if (i == -2) {
409 /*
410 * The f00f hack workaround has triggered, so
411 * treat the fault as an illegal instruction
412 * (T_PRIVINFLT) instead of a page fault.
413 */
414 type = frame->tf_trapno = T_PRIVINFLT;
415
416 /* Proceed as in that case. */
417 ucode = ILL_PRVOPC;
418 i = SIGILL;
419 break;
420 }
421 #endif
422 if (i == -1)
423 goto userout;
424 if (i == 0)
425 goto user;
426
427 if (i == SIGSEGV)
428 ucode = SEGV_MAPERR;
429 else {
430 if (prot_fault_translation == 0) {
431 /*
432 * Autodetect.
433 * This check also covers the images
434 * without the ABI-tag ELF note.
435 */
436 if (curproc->p_sysent ==
437 &elf32_freebsd_sysvec &&
438 p->p_osrel >= 700004) {
439 i = SIGSEGV;
440 ucode = SEGV_ACCERR;
441 } else {
442 i = SIGBUS;
443 ucode = BUS_PAGE_FAULT;
444 }
445 } else if (prot_fault_translation == 1) {
446 /*
447 * Always compat mode.
448 */
449 i = SIGBUS;
450 ucode = BUS_PAGE_FAULT;
451 } else {
452 /*
453 * Always SIGSEGV mode.
454 */
455 i = SIGSEGV;
456 ucode = SEGV_ACCERR;
457 }
458 }
459 addr = eva;
460 break;
461
462 case T_DIVIDE: /* integer divide fault */
463 ucode = FPE_INTDIV;
464 i = SIGFPE;
465 break;
466
467 #ifdef DEV_ISA
468 case T_NMI:
469 #ifdef POWERFAIL_NMI
470 #ifndef TIMER_FREQ
471 # define TIMER_FREQ 1193182
472 #endif
473 mtx_lock(&Giant);
474 if (time_second - lastalert > 10) {
475 log(LOG_WARNING, "NMI: power fail\n");
476 sysbeep(TIMER_FREQ/880, hz);
477 lastalert = time_second;
478 }
479 mtx_unlock(&Giant);
480 goto userout;
481 #else /* !POWERFAIL_NMI */
482 /* machine/parity/power fail/"kitchen sink" faults */
483 /* XXX Giant */
484 if (isa_nmi(code) == 0) {
485 #ifdef KDB
486 /*
487 * NMI can be hooked up to a pushbutton
488 * for debugging.
489 */
490 if (kdb_on_nmi) {
491 printf ("NMI ... going to debugger\n");
492 kdb_trap(type, 0, frame);
493 }
494 #endif /* KDB */
495 goto userout;
496 } else if (panic_on_nmi)
497 panic("NMI indicates hardware failure");
498 break;
499 #endif /* POWERFAIL_NMI */
500 #endif /* DEV_ISA */
501
502 case T_OFLOW: /* integer overflow fault */
503 ucode = FPE_INTOVF;
504 i = SIGFPE;
505 break;
506
507 case T_BOUND: /* bounds check fault */
508 ucode = FPE_FLTSUB;
509 i = SIGFPE;
510 break;
511
512 case T_DNA:
513 #ifdef DEV_NPX
514 /* transparent fault (due to context switch "late") */
515 if (npxdna())
516 goto userout;
517 #endif
518 printf("pid %d killed due to lack of floating point\n",
519 p->p_pid);
520 i = SIGKILL;
521 ucode = 0;
522 break;
523
524 case T_FPOPFLT: /* FPU operand fetch fault */
525 ucode = ILL_COPROC;
526 i = SIGILL;
527 break;
528
529 case T_XMMFLT: /* SIMD floating-point exception */
530 ucode = 0; /* XXX */
531 i = SIGFPE;
532 break;
533 }
534 } else {
535 /* kernel trap */
536
537 KASSERT(cold || td->td_ucred != NULL,
538 ("kernel trap doesn't have ucred"));
539 switch (type) {
540 case T_PAGEFLT: /* page fault */
541 (void) trap_pfault(frame, FALSE, eva);
542 goto out;
543
544 case T_DNA:
545 #ifdef DEV_NPX
546 /*
547 * The kernel is apparently using npx for copying.
548 * XXX this should be fatal unless the kernel has
549 * registered such use.
550 */
551 if (npxdna())
552 goto out;
553 #endif
554 break;
555
556 /*
557 * The following two traps can happen in
558 * vm86 mode, and, if so, we want to handle
559 * them specially.
560 */
561 case T_PROTFLT: /* general protection fault */
562 case T_STKFLT: /* stack fault */
563 if (frame->tf_eflags & PSL_VM) {
564 i = vm86_emulate((struct vm86frame *)frame);
565 if (i != 0)
566 /*
567 * returns to original process
568 */
569 vm86_trap((struct vm86frame *)frame);
570 goto out;
571 }
572 if (type == T_STKFLT)
573 break;
574
575 /* FALL THROUGH */
576
577 case T_SEGNPFLT: /* segment not present fault */
578 if (PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL)
579 break;
580
581 /*
582 * Invalid %fs's and %gs's can be created using
583 * procfs or PT_SETREGS or by invalidating the
584 * underlying LDT entry. This causes a fault
585 * in kernel mode when the kernel attempts to
586 * switch contexts. Lose the bad context
587 * (XXX) so that we can continue, and generate
588 * a signal.
589 */
590 if (frame->tf_eip == (int)cpu_switch_load_gs) {
591 PCPU_GET(curpcb)->pcb_gs = 0;
592 #if 0
593 PROC_LOCK(p);
594 psignal(p, SIGBUS);
595 PROC_UNLOCK(p);
596 #endif
597 goto out;
598 }
599
600 if (td->td_intr_nesting_level != 0)
601 break;
602
603 /*
604 * Invalid segment selectors and out of bounds
605 * %eip's and %esp's can be set up in user mode.
606 * This causes a fault in kernel mode when the
607 * kernel tries to return to user mode. We want
608 * to get this fault so that we can fix the
609 * problem here and not have to check all the
610 * selectors and pointers when the user changes
611 * them.
612 */
613 if (frame->tf_eip == (int)doreti_iret) {
614 frame->tf_eip = (int)doreti_iret_fault;
615 goto out;
616 }
617 if (frame->tf_eip == (int)doreti_popl_ds) {
618 frame->tf_eip = (int)doreti_popl_ds_fault;
619 goto out;
620 }
621 if (frame->tf_eip == (int)doreti_popl_es) {
622 frame->tf_eip = (int)doreti_popl_es_fault;
623 goto out;
624 }
625 if (frame->tf_eip == (int)doreti_popl_fs) {
626 frame->tf_eip = (int)doreti_popl_fs_fault;
627 goto out;
628 }
629 if (PCPU_GET(curpcb)->pcb_onfault != NULL) {
630 frame->tf_eip =
631 (int)PCPU_GET(curpcb)->pcb_onfault;
632 goto out;
633 }
634 break;
635
636 case T_TSSFLT:
637 /*
638 * PSL_NT can be set in user mode and isn't cleared
639 * automatically when the kernel is entered. This
640 * causes a TSS fault when the kernel attempts to
641 * `iret' because the TSS link is uninitialized. We
642 * want to get this fault so that we can fix the
643 * problem here and not every time the kernel is
644 * entered.
645 */
646 if (frame->tf_eflags & PSL_NT) {
647 frame->tf_eflags &= ~PSL_NT;
648 goto out;
649 }
650 break;
651
652 case T_TRCTRAP: /* trace trap */
653 if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) {
654 /*
655 * We've just entered system mode via the
656 * syscall lcall. Continue single stepping
657 * silently until the syscall handler has
658 * saved the flags.
659 */
660 goto out;
661 }
662 if (frame->tf_eip == (int)IDTVEC(lcall_syscall) + 1) {
663 /*
664 * The syscall handler has now saved the
665 * flags. Stop single stepping it.
666 */
667 frame->tf_eflags &= ~PSL_T;
668 goto out;
669 }
670 /*
671 * Ignore debug register trace traps due to
672 * accesses in the user's address space, which
673 * can happen under several conditions such as
674 * if a user sets a watchpoint on a buffer and
675 * then passes that buffer to a system call.
676 * We still want to get TRCTRAPS for addresses
677 * in kernel space because that is useful when
678 * debugging the kernel.
679 */
680 /* XXX Giant */
681 if (user_dbreg_trap() &&
682 !(PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL)) {
683 /*
684 * Reset breakpoint bits because the
685 * processor doesn't
686 */
687 load_dr6(rdr6() & 0xfffffff0);
688 goto out;
689 }
690 /*
691 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
692 */
693 case T_BPTFLT:
694 /*
695 * If KDB is enabled, let it handle the debugger trap.
696 * Otherwise, debugger traps "can't happen".
697 */
698 #ifdef KDB
699 if (kdb_trap(type, 0, frame))
700 goto out;
701 #endif
702 break;
703
704 #ifdef DEV_ISA
705 case T_NMI:
706 #ifdef POWERFAIL_NMI
707 mtx_lock(&Giant);
708 if (time_second - lastalert > 10) {
709 log(LOG_WARNING, "NMI: power fail\n");
710 sysbeep(TIMER_FREQ/880, hz);
711 lastalert = time_second;
712 }
713 mtx_unlock(&Giant);
714 goto out;
715 #else /* !POWERFAIL_NMI */
716 /* XXX Giant */
717 /* machine/parity/power fail/"kitchen sink" faults */
718 if (isa_nmi(code) == 0) {
719 #ifdef KDB
720 /*
721 * NMI can be hooked up to a pushbutton
722 * for debugging.
723 */
724 if (kdb_on_nmi) {
725 printf ("NMI ... going to debugger\n");
726 kdb_trap(type, 0, frame);
727 }
728 #endif /* KDB */
729 goto out;
730 } else if (panic_on_nmi == 0)
731 goto out;
732 /* FALLTHROUGH */
733 #endif /* POWERFAIL_NMI */
734 #endif /* DEV_ISA */
735 }
736
737 trap_fatal(frame, eva);
738 goto out;
739 }
740
741 /* Translate fault for emulators (e.g. Linux) */
742 if (*p->p_sysent->sv_transtrap)
743 i = (*p->p_sysent->sv_transtrap)(i, type);
744
745 ksiginfo_init_trap(&ksi);
746 ksi.ksi_signo = i;
747 ksi.ksi_code = ucode;
748 ksi.ksi_addr = (void *)addr;
749 ksi.ksi_trapno = type;
750 trapsignal(td, &ksi);
751
752 #ifdef DEBUG
753 if (type <= MAX_TRAP_MSG) {
754 uprintf("fatal process exception: %s",
755 trap_msg[type]);
756 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
757 uprintf(", fault VA = 0x%lx", (u_long)eva);
758 uprintf("\n");
759 }
760 #endif
761
762 user:
763 userret(td, frame);
764 mtx_assert(&Giant, MA_NOTOWNED);
765 userout:
766 out:
767 return;
768 }
769
770 static int
771 trap_pfault(frame, usermode, eva)
772 struct trapframe *frame;
773 int usermode;
774 vm_offset_t eva;
775 {
776 vm_offset_t va;
777 struct vmspace *vm = NULL;
778 vm_map_t map;
779 int rv = 0;
780 vm_prot_t ftype;
781 struct thread *td = curthread;
782 struct proc *p = td->td_proc;
783
784 va = trunc_page(eva);
785 if (va >= KERNBASE) {
786 /*
787 * Don't allow user-mode faults in kernel address space.
788 * An exception: if the faulting address is the invalid
789 * instruction entry in the IDT, then the Intel Pentium
790 * F00F bug workaround was triggered, and we need to
791 * treat it is as an illegal instruction, and not a page
792 * fault.
793 */
794 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
795 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug)
796 return -2;
797 #endif
798 if (usermode)
799 goto nogo;
800
801 map = kernel_map;
802 } else {
803 /*
804 * This is a fault on non-kernel virtual memory.
805 * vm is initialized above to NULL. If curproc is NULL
806 * or curproc->p_vmspace is NULL the fault is fatal.
807 */
808 if (p != NULL)
809 vm = p->p_vmspace;
810
811 if (vm == NULL)
812 goto nogo;
813
814 map = &vm->vm_map;
815 }
816
817 /*
818 * PGEX_I is defined only if the execute disable bit capability is
819 * supported and enabled.
820 */
821 if (frame->tf_err & PGEX_W)
822 ftype = VM_PROT_WRITE;
823 #ifdef PAE
824 else if ((frame->tf_err & PGEX_I) && pg_nx != 0)
825 ftype = VM_PROT_EXECUTE;
826 #endif
827 else
828 ftype = VM_PROT_READ;
829
830 if (map != kernel_map) {
831 /*
832 * Keep swapout from messing with us during this
833 * critical time.
834 */
835 PROC_LOCK(p);
836 ++p->p_lock;
837 PROC_UNLOCK(p);
838
839 /* Fault in the user page: */
840 rv = vm_fault(map, va, ftype,
841 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY
842 : VM_FAULT_NORMAL);
843
844 PROC_LOCK(p);
845 --p->p_lock;
846 PROC_UNLOCK(p);
847 } else {
848 /*
849 * Don't have to worry about process locking or stacks in the
850 * kernel.
851 */
852 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
853 }
854 if (rv == KERN_SUCCESS)
855 return (0);
856 nogo:
857 if (!usermode) {
858 if (td->td_intr_nesting_level == 0 &&
859 PCPU_GET(curpcb)->pcb_onfault != NULL) {
860 frame->tf_eip = (int)PCPU_GET(curpcb)->pcb_onfault;
861 return (0);
862 }
863 trap_fatal(frame, eva);
864 return (-1);
865 }
866
867 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
868 }
869
870 static void
871 trap_fatal(frame, eva)
872 struct trapframe *frame;
873 vm_offset_t eva;
874 {
875 int code, ss, esp;
876 u_int type;
877 struct soft_segment_descriptor softseg;
878 char *msg;
879
880 code = frame->tf_err;
881 type = frame->tf_trapno;
882 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg);
883
884 if (type <= MAX_TRAP_MSG)
885 msg = trap_msg[type];
886 else
887 msg = "UNKNOWN";
888 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg,
889 frame->tf_eflags & PSL_VM ? "vm86" :
890 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
891 #ifdef SMP
892 /* two separate prints in case of a trap on an unmapped page */
893 printf("cpuid = %d; ", PCPU_GET(cpuid));
894 printf("apic id = %02x\n", PCPU_GET(apic_id));
895 #endif
896 if (type == T_PAGEFLT) {
897 printf("fault virtual address = 0x%x\n", eva);
898 printf("fault code = %s %s, %s\n",
899 code & PGEX_U ? "user" : "supervisor",
900 code & PGEX_W ? "write" : "read",
901 code & PGEX_P ? "protection violation" : "page not present");
902 }
903 printf("instruction pointer = 0x%x:0x%x\n",
904 frame->tf_cs & 0xffff, frame->tf_eip);
905 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) {
906 ss = frame->tf_ss & 0xffff;
907 esp = frame->tf_esp;
908 } else {
909 ss = GSEL(GDATA_SEL, SEL_KPL);
910 esp = (int)&frame->tf_esp;
911 }
912 printf("stack pointer = 0x%x:0x%x\n", ss, esp);
913 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp);
914 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n",
915 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
916 printf(" = DPL %d, pres %d, def32 %d, gran %d\n",
917 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32,
918 softseg.ssd_gran);
919 printf("processor eflags = ");
920 if (frame->tf_eflags & PSL_T)
921 printf("trace trap, ");
922 if (frame->tf_eflags & PSL_I)
923 printf("interrupt enabled, ");
924 if (frame->tf_eflags & PSL_NT)
925 printf("nested task, ");
926 if (frame->tf_eflags & PSL_RF)
927 printf("resume, ");
928 if (frame->tf_eflags & PSL_VM)
929 printf("vm86, ");
930 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12);
931 printf("current process = ");
932 if (curproc) {
933 printf("%lu (%s)\n", (u_long)curproc->p_pid, curproc->p_comm);
934 } else {
935 printf("Idle\n");
936 }
937
938 #ifdef KDB
939 if (debugger_on_panic || kdb_active) {
940 frame->tf_err = eva; /* smuggle fault address to ddb */
941 if (kdb_trap(type, 0, frame)) {
942 frame->tf_err = code; /* restore error code */
943 return;
944 }
945 frame->tf_err = code; /* restore error code */
946 }
947 #endif
948 printf("trap number = %d\n", type);
949 if (type <= MAX_TRAP_MSG)
950 panic("%s", trap_msg[type]);
951 else
952 panic("unknown/reserved trap");
953 }
954
955 /*
956 * Double fault handler. Called when a fault occurs while writing
957 * a frame for a trap/exception onto the stack. This usually occurs
958 * when the stack overflows (such is the case with infinite recursion,
959 * for example).
960 *
961 * XXX Note that the current PTD gets replaced by IdlePTD when the
962 * task switch occurs. This means that the stack that was active at
963 * the time of the double fault is not available at <kstack> unless
964 * the machine was idle when the double fault occurred. The downside
965 * of this is that "trace <ebp>" in ddb won't work.
966 */
967 void
968 dblfault_handler()
969 {
970 #ifdef KDTRACE_HOOKS
971 if (dtrace_doubletrap_func != NULL)
972 (*dtrace_doubletrap_func)();
973 #endif
974 printf("\nFatal double fault:\n");
975 printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip));
976 printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp));
977 printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp));
978 #ifdef SMP
979 /* two separate prints in case of a trap on an unmapped page */
980 printf("cpuid = %d; ", PCPU_GET(cpuid));
981 printf("apic id = %02x\n", PCPU_GET(apic_id));
982 #endif
983 panic("double fault");
984 }
985
986 /*
987 * syscall - system call request C handler
988 *
989 * A system call is essentially treated as a trap.
990 */
991 void
992 syscall(struct trapframe *frame)
993 {
994 caddr_t params;
995 struct sysent *callp;
996 struct thread *td = curthread;
997 struct proc *p = td->td_proc;
998 register_t orig_tf_eflags;
999 int error;
1000 int narg;
1001 int args[8];
1002 u_int code;
1003 ksiginfo_t ksi;
1004
1005 PCPU_INC(cnt.v_syscall);
1006
1007 #ifdef DIAGNOSTIC
1008 if (ISPL(frame->tf_cs) != SEL_UPL) {
1009 panic("syscall");
1010 /* NOT REACHED */
1011 }
1012 #endif
1013
1014 td->td_pticks = 0;
1015 td->td_frame = frame;
1016 if (td->td_ucred != p->p_ucred)
1017 cred_update_thread(td);
1018 #ifdef KSE
1019 if (p->p_flag & P_SA)
1020 thread_user_enter(td);
1021 #endif
1022 params = (caddr_t)frame->tf_esp + sizeof(int);
1023 code = frame->tf_eax;
1024 orig_tf_eflags = frame->tf_eflags;
1025
1026 if (p->p_sysent->sv_prepsyscall) {
1027 /*
1028 * The prep code is MP aware.
1029 */
1030 (*p->p_sysent->sv_prepsyscall)(frame, args, &code, ¶ms);
1031 } else {
1032 /*
1033 * Need to check if this is a 32 bit or 64 bit syscall.
1034 * fuword is MP aware.
1035 */
1036 if (code == SYS_syscall) {
1037 /*
1038 * Code is first argument, followed by actual args.
1039 */
1040 code = fuword(params);
1041 params += sizeof(int);
1042 } else if (code == SYS___syscall) {
1043 /*
1044 * Like syscall, but code is a quad, so as to maintain
1045 * quad alignment for the rest of the arguments.
1046 */
1047 code = fuword(params);
1048 params += sizeof(quad_t);
1049 }
1050 }
1051
1052 if (p->p_sysent->sv_mask)
1053 code &= p->p_sysent->sv_mask;
1054
1055 if (code >= p->p_sysent->sv_size)
1056 callp = &p->p_sysent->sv_table[0];
1057 else
1058 callp = &p->p_sysent->sv_table[code];
1059
1060 narg = callp->sy_narg;
1061
1062 /*
1063 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware
1064 */
1065 if (params != NULL && narg != 0)
1066 error = copyin(params, (caddr_t)args,
1067 (u_int)(narg * sizeof(int)));
1068 else
1069 error = 0;
1070
1071 #ifdef KTRACE
1072 if (KTRPOINT(td, KTR_SYSCALL))
1073 ktrsyscall(code, narg, args);
1074 #endif
1075
1076 CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td,
1077 td->td_proc->p_pid, td->td_proc->p_comm, code);
1078
1079 td->td_syscalls++;
1080
1081 if (error == 0) {
1082 td->td_retval[0] = 0;
1083 td->td_retval[1] = frame->tf_edx;
1084
1085 STOPEVENT(p, S_SCE, narg);
1086
1087 PTRACESTOP_SC(p, td, S_PT_SCE);
1088
1089 #ifdef KDTRACE_HOOKS
1090 /*
1091 * If the systrace module has registered it's probe
1092 * callback and if there is a probe active for the
1093 * syscall 'entry', process the probe.
1094 */
1095 if (systrace_probe_func != NULL && callp->sy_entry != 0)
1096 (*systrace_probe_func)(callp->sy_entry, code, callp,
1097 args);
1098 #endif
1099
1100 AUDIT_SYSCALL_ENTER(code, td);
1101 error = (*callp->sy_call)(td, args);
1102 AUDIT_SYSCALL_EXIT(error, td);
1103
1104 /* Save the latest error return value. */
1105 td->td_errno = error;
1106
1107 #ifdef KDTRACE_HOOKS
1108 /*
1109 * If the systrace module has registered it's probe
1110 * callback and if there is a probe active for the
1111 * syscall 'return', process the probe.
1112 */
1113 if (systrace_probe_func != NULL && callp->sy_return != 0)
1114 (*systrace_probe_func)(callp->sy_return, code, callp,
1115 args);
1116 #endif
1117 }
1118
1119 switch (error) {
1120 case 0:
1121 frame->tf_eax = td->td_retval[0];
1122 frame->tf_edx = td->td_retval[1];
1123 frame->tf_eflags &= ~PSL_C;
1124 break;
1125
1126 case ERESTART:
1127 /*
1128 * Reconstruct pc, assuming lcall $X,y is 7 bytes,
1129 * int 0x80 is 2 bytes. We saved this in tf_err.
1130 */
1131 frame->tf_eip -= frame->tf_err;
1132 break;
1133
1134 case EJUSTRETURN:
1135 break;
1136
1137 default:
1138 if (p->p_sysent->sv_errsize) {
1139 if (error >= p->p_sysent->sv_errsize)
1140 error = -1; /* XXX */
1141 else
1142 error = p->p_sysent->sv_errtbl[error];
1143 }
1144 frame->tf_eax = error;
1145 frame->tf_eflags |= PSL_C;
1146 break;
1147 }
1148
1149 /*
1150 * Traced syscall.
1151 */
1152 if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) {
1153 frame->tf_eflags &= ~PSL_T;
1154 ksiginfo_init_trap(&ksi);
1155 ksi.ksi_signo = SIGTRAP;
1156 ksi.ksi_code = TRAP_TRACE;
1157 ksi.ksi_addr = (void *)frame->tf_eip;
1158 trapsignal(td, &ksi);
1159 }
1160
1161 /*
1162 * Check for misbehavior.
1163 */
1164 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
1165 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???");
1166 KASSERT(td->td_critnest == 0,
1167 ("System call %s returning in a critical section",
1168 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"));
1169 KASSERT(td->td_locks == 0,
1170 ("System call %s returning with %d locks held",
1171 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???",
1172 td->td_locks));
1173
1174 /*
1175 * Handle reschedule and other end-of-syscall issues
1176 */
1177 userret(td, frame);
1178
1179 CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td,
1180 td->td_proc->p_pid, td->td_proc->p_comm, code);
1181
1182 #ifdef KTRACE
1183 if (KTRPOINT(td, KTR_SYSRET))
1184 ktrsysret(code, error, td->td_retval[0]);
1185 #endif
1186
1187 /*
1188 * This works because errno is findable through the
1189 * register set. If we ever support an emulation where this
1190 * is not the case, this code will need to be revisited.
1191 */
1192 STOPEVENT(p, S_SCX, code);
1193
1194 PTRACESTOP_SC(p, td, S_PT_SCX);
1195 }
1196
Cache object: 6a1423934204a2b164d4d2581d263995
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