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 * $FreeBSD$
39 */
40
41 /*
42 * 386 Trap and System call handling
43 */
44
45 #include "opt_cpu.h"
46 #include "opt_ddb.h"
47 #include "opt_ktrace.h"
48 #include "opt_trap.h"
49 #include "opt_vm86.h"
50
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/proc.h>
54 #include <sys/pioctl.h>
55 #include <sys/kernel.h>
56 #include <sys/resourcevar.h>
57 #include <sys/signalvar.h>
58 #include <sys/syscall.h>
59 #include <sys/sysent.h>
60 #include <sys/uio.h>
61 #include <sys/vmmeter.h>
62 #ifdef KTRACE
63 #include <sys/ktrace.h>
64 #endif
65
66 #include <vm/vm.h>
67 #include <vm/vm_param.h>
68 #include <vm/vm_prot.h>
69 #include <sys/lock.h>
70 #include <vm/pmap.h>
71 #include <vm/vm_kern.h>
72 #include <vm/vm_map.h>
73 #include <vm/vm_page.h>
74 #include <vm/vm_extern.h>
75
76 #include <machine/cpu.h>
77 #include <machine/ipl.h>
78 #include <machine/md_var.h>
79 #include <machine/pcb.h>
80 #ifdef SMP
81 #include <machine/smp.h>
82 #endif
83 #include <machine/tss.h>
84
85 #include <i386/isa/intr_machdep.h>
86
87 #ifdef POWERFAIL_NMI
88 #include <sys/syslog.h>
89 #include <machine/clock.h>
90 #endif
91
92 #ifdef VM86
93 #include <machine/vm86.h>
94 #endif
95
96 #ifdef DDB
97 extern int in_Debugger, debugger_on_panic;
98 #endif
99
100 #include "isa.h"
101 #include "npx.h"
102
103 extern struct i386tss common_tss;
104
105 int (*pmath_emulate) __P((struct trapframe *));
106
107 extern void trap __P((struct trapframe frame));
108 extern int trapwrite __P((unsigned addr));
109 extern void syscall __P((struct trapframe frame));
110
111 static int trap_pfault __P((struct trapframe *, int, vm_offset_t));
112 static void trap_fatal __P((struct trapframe *, vm_offset_t));
113 void dblfault_handler __P((void));
114
115 extern inthand_t IDTVEC(syscall);
116
117 #define MAX_TRAP_MSG 28
118 static char *trap_msg[] = {
119 "", /* 0 unused */
120 "privileged instruction fault", /* 1 T_PRIVINFLT */
121 "", /* 2 unused */
122 "breakpoint instruction fault", /* 3 T_BPTFLT */
123 "", /* 4 unused */
124 "", /* 5 unused */
125 "arithmetic trap", /* 6 T_ARITHTRAP */
126 "system forced exception", /* 7 T_ASTFLT */
127 "", /* 8 unused */
128 "general protection fault", /* 9 T_PROTFLT */
129 "trace trap", /* 10 T_TRCTRAP */
130 "", /* 11 unused */
131 "page fault", /* 12 T_PAGEFLT */
132 "", /* 13 unused */
133 "alignment fault", /* 14 T_ALIGNFLT */
134 "", /* 15 unused */
135 "", /* 16 unused */
136 "", /* 17 unused */
137 "integer divide fault", /* 18 T_DIVIDE */
138 "non-maskable interrupt trap", /* 19 T_NMI */
139 "overflow trap", /* 20 T_OFLOW */
140 "FPU bounds check fault", /* 21 T_BOUND */
141 "FPU device not available", /* 22 T_DNA */
142 "double fault", /* 23 T_DOUBLEFLT */
143 "FPU operand fetch fault", /* 24 T_FPOPFLT */
144 "invalid TSS fault", /* 25 T_TSSFLT */
145 "segment not present fault", /* 26 T_SEGNPFLT */
146 "stack fault", /* 27 T_STKFLT */
147 "machine check trap", /* 28 T_MCHK */
148 };
149
150 static __inline void userret __P((struct proc *p, struct trapframe *frame,
151 u_quad_t oticks));
152
153 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
154 extern struct gate_descriptor *t_idt;
155 extern int has_f00f_bug;
156 #endif
157
158 static __inline void
159 userret(p, frame, oticks)
160 struct proc *p;
161 struct trapframe *frame;
162 u_quad_t oticks;
163 {
164 int sig, s;
165
166 while ((sig = CURSIG(p)) != 0)
167 postsig(sig);
168
169 #if 0
170 if (!want_resched &&
171 (p->p_priority <= p->p_usrpri) &&
172 (p->p_rtprio.type == RTP_PRIO_NORMAL)) {
173 int newpriority;
174 p->p_estcpu += 1;
175 newpriority = PUSER + p->p_estcpu / 4 + 2 * p->p_nice;
176 newpriority = min(newpriority, MAXPRI);
177 p->p_usrpri = newpriority;
178 }
179 #endif
180
181 p->p_priority = p->p_usrpri;
182 if (want_resched) {
183 /*
184 * Since we are curproc, clock will normally just change
185 * our priority without moving us from one queue to another
186 * (since the running process is not on a queue.)
187 * If that happened after we setrunqueue ourselves but before we
188 * mi_switch()'ed, we might not be on the queue indicated by
189 * our priority.
190 */
191 s = splhigh();
192 setrunqueue(p);
193 p->p_stats->p_ru.ru_nivcsw++;
194 mi_switch();
195 splx(s);
196 while ((sig = CURSIG(p)) != 0)
197 postsig(sig);
198 }
199 /*
200 * Charge system time if profiling.
201 */
202 if (p->p_flag & P_PROFIL)
203 addupc_task(p, frame->tf_eip,
204 (u_int)(p->p_sticks - oticks) * psratio);
205
206 curpriority = p->p_priority;
207 }
208
209 /*
210 * Exception, fault, and trap interface to the FreeBSD kernel.
211 * This common code is called from assembly language IDT gate entry
212 * routines that prepare a suitable stack frame, and restore this
213 * frame after the exception has been processed.
214 */
215
216 void
217 trap(frame)
218 struct trapframe frame;
219 {
220 struct proc *p = curproc;
221 u_quad_t sticks = 0;
222 int i = 0, ucode = 0, type, code;
223 vm_offset_t eva;
224
225 if (!(frame.tf_eflags & PSL_I)) {
226 /*
227 * Buggy application or kernel code has disabled interrupts
228 * and then trapped. Enabling interrupts now is wrong, but
229 * it is better than running with interrupts disabled until
230 * they are accidentally enabled later.
231 */
232 type = frame.tf_trapno;
233 if (ISPL(frame.tf_cs) == SEL_UPL || (frame.tf_eflags & PSL_VM))
234 printf(
235 "pid %ld (%s): trap %d with interrupts disabled\n",
236 (long)curproc->p_pid, curproc->p_comm, type);
237 else if (type != T_BPTFLT && type != T_TRCTRAP)
238 /*
239 * XXX not quite right, since this may be for a
240 * multiple fault in user mode.
241 */
242 printf("kernel trap %d with interrupts disabled\n",
243 type);
244 enable_intr();
245 }
246
247 eva = 0;
248 if (frame.tf_trapno == T_PAGEFLT) {
249 /*
250 * For some Cyrix CPUs, %cr2 is clobbered by interrupts.
251 * This problem is worked around by using an interrupt
252 * gate for the pagefault handler. We are finally ready
253 * to read %cr2 and then must reenable interrupts.
254 *
255 * XXX this should be in the switch statement, but the
256 * NO_FOOF_HACK and VM86 goto and ifdefs obfuscate the
257 * flow of control too much for this to be obviously
258 * correct.
259 */
260 eva = rcr2();
261 enable_intr();
262 }
263
264 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
265 restart:
266 #endif
267 type = frame.tf_trapno;
268 code = frame.tf_err;
269
270 #ifdef VM86
271 if (in_vm86call) {
272 if (frame.tf_eflags & PSL_VM &&
273 (type == T_PROTFLT || type == T_STKFLT)) {
274 i = vm86_emulate((struct vm86frame *)&frame);
275 if (i != 0)
276 /*
277 * returns to original process
278 */
279 vm86_trap((struct vm86frame *)&frame);
280 return;
281 }
282 switch (type) {
283 /*
284 * these traps want either a process context, or
285 * assume a normal userspace trap.
286 */
287 case T_PROTFLT:
288 case T_SEGNPFLT:
289 trap_fatal(&frame, eva);
290 return;
291 case T_TRCTRAP:
292 type = T_BPTFLT; /* kernel breakpoint */
293 /* FALL THROUGH */
294 }
295 goto kernel_trap; /* normal kernel trap handling */
296 }
297 #endif
298
299 if ((ISPL(frame.tf_cs) == SEL_UPL) || (frame.tf_eflags & PSL_VM)) {
300 /* user trap */
301
302 sticks = p->p_sticks;
303 p->p_md.md_regs = &frame;
304
305 switch (type) {
306 case T_PRIVINFLT: /* privileged instruction fault */
307 ucode = type;
308 i = SIGILL;
309 break;
310
311 case T_BPTFLT: /* bpt instruction fault */
312 case T_TRCTRAP: /* trace trap */
313 frame.tf_eflags &= ~PSL_T;
314 i = SIGTRAP;
315 break;
316
317 case T_ARITHTRAP: /* arithmetic trap */
318 ucode = code;
319 i = SIGFPE;
320 break;
321
322 case T_ASTFLT: /* Allow process switch */
323 astoff();
324 cnt.v_soft++;
325 if (p->p_flag & P_OWEUPC) {
326 p->p_flag &= ~P_OWEUPC;
327 addupc_task(p, p->p_stats->p_prof.pr_addr,
328 p->p_stats->p_prof.pr_ticks);
329 }
330 goto out;
331
332 /*
333 * The following two traps can happen in
334 * vm86 mode, and, if so, we want to handle
335 * them specially.
336 */
337 case T_PROTFLT: /* general protection fault */
338 case T_STKFLT: /* stack fault */
339 #ifdef VM86
340 if (frame.tf_eflags & PSL_VM) {
341 i = vm86_emulate((struct vm86frame *)&frame);
342 if (i == 0)
343 goto out;
344 break;
345 }
346 #endif /* VM86 */
347 /* FALL THROUGH */
348
349 case T_SEGNPFLT: /* segment not present fault */
350 case T_TSSFLT: /* invalid TSS fault */
351 case T_DOUBLEFLT: /* double fault */
352 default:
353 ucode = code + BUS_SEGM_FAULT ;
354 i = SIGBUS;
355 break;
356
357 case T_PAGEFLT: /* page fault */
358 i = trap_pfault(&frame, TRUE, eva);
359 if (i == -1)
360 return;
361 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
362 if (i == -2)
363 goto restart;
364 #endif
365 if (i == 0)
366 goto out;
367
368 ucode = T_PAGEFLT;
369 break;
370
371 case T_DIVIDE: /* integer divide fault */
372 ucode = FPE_INTDIV_TRAP;
373 i = SIGFPE;
374 break;
375
376 #if NISA > 0
377 case T_NMI:
378 #ifdef POWERFAIL_NMI
379 goto handle_powerfail;
380 #else /* !POWERFAIL_NMI */
381 #ifdef DDB
382 /* NMI can be hooked up to a pushbutton for debugging */
383 printf ("NMI ... going to debugger\n");
384 if (kdb_trap (type, 0, &frame))
385 return;
386 #endif /* DDB */
387 /* machine/parity/power fail/"kitchen sink" faults */
388 if (isa_nmi(code) == 0) return;
389 panic("NMI indicates hardware failure");
390 #endif /* POWERFAIL_NMI */
391 #endif /* NISA > 0 */
392
393 case T_OFLOW: /* integer overflow fault */
394 ucode = FPE_INTOVF_TRAP;
395 i = SIGFPE;
396 break;
397
398 case T_BOUND: /* bounds check fault */
399 ucode = FPE_SUBRNG_TRAP;
400 i = SIGFPE;
401 break;
402
403 case T_DNA:
404 #if NNPX > 0
405 /* if a transparent fault (due to context switch "late") */
406 if (npxdna())
407 return;
408 #endif
409 if (!pmath_emulate) {
410 i = SIGFPE;
411 ucode = FPE_FPU_NP_TRAP;
412 break;
413 }
414 i = (*pmath_emulate)(&frame);
415 if (i == 0) {
416 if (!(frame.tf_eflags & PSL_T))
417 return;
418 frame.tf_eflags &= ~PSL_T;
419 i = SIGTRAP;
420 }
421 /* else ucode = emulator_only_knows() XXX */
422 break;
423
424 case T_FPOPFLT: /* FPU operand fetch fault */
425 ucode = T_FPOPFLT;
426 i = SIGILL;
427 break;
428 }
429 } else {
430 #ifdef VM86
431 kernel_trap:
432 #endif
433 /* kernel trap */
434
435 switch (type) {
436 case T_PAGEFLT: /* page fault */
437 (void) trap_pfault(&frame, FALSE, eva);
438 return;
439
440 case T_DNA:
441 #if NNPX > 0
442 /*
443 * The kernel is apparently using npx for copying.
444 * XXX this should be fatal unless the kernel has
445 * registered such use.
446 */
447 if (npxdna())
448 return;
449 #endif
450 break;
451
452 case T_PROTFLT: /* general protection fault */
453 case T_SEGNPFLT: /* segment not present fault */
454 /*
455 * Invalid segment selectors and out of bounds
456 * %eip's and %esp's can be set up in user mode.
457 * This causes a fault in kernel mode when the
458 * kernel tries to return to user mode. We want
459 * to get this fault so that we can fix the
460 * problem here and not have to check all the
461 * selectors and pointers when the user changes
462 * them.
463 */
464 #define MAYBE_DORETI_FAULT(where, whereto) \
465 do { \
466 if (frame.tf_eip == (int)where) { \
467 frame.tf_eip = (int)whereto; \
468 return; \
469 } \
470 } while (0)
471
472 if (intr_nesting_level == 0) {
473 /*
474 * Invalid %fs's and %gs's can be created using
475 * procfs or PT_SETREGS or by invalidating the
476 * underlying LDT entry. This causes a fault
477 * in kernel mode when the kernel attempts to
478 * switch contexts. Lose the bad context
479 * (XXX) so that we can continue, and generate
480 * a signal.
481 */
482 if (frame.tf_eip == (int)cpu_switch_load_fs) {
483 curpcb->pcb_fs = 0;
484 psignal(p, SIGBUS);
485 return;
486 }
487 if (frame.tf_eip == (int)cpu_switch_load_gs) {
488 curpcb->pcb_gs = 0;
489 psignal(p, SIGBUS);
490 return;
491 }
492 MAYBE_DORETI_FAULT(doreti_iret,
493 doreti_iret_fault);
494 MAYBE_DORETI_FAULT(doreti_popl_ds,
495 doreti_popl_ds_fault);
496 MAYBE_DORETI_FAULT(doreti_popl_es,
497 doreti_popl_es_fault);
498 if (curpcb && curpcb->pcb_onfault) {
499 frame.tf_eip = (int)curpcb->pcb_onfault;
500 return;
501 }
502 }
503 break;
504
505 case T_TSSFLT:
506 /*
507 * PSL_NT can be set in user mode and isn't cleared
508 * automatically when the kernel is entered. This
509 * causes a TSS fault when the kernel attempts to
510 * `iret' because the TSS link is uninitialized. We
511 * want to get this fault so that we can fix the
512 * problem here and not every time the kernel is
513 * entered.
514 */
515 if (frame.tf_eflags & PSL_NT) {
516 frame.tf_eflags &= ~PSL_NT;
517 return;
518 }
519 break;
520
521 case T_TRCTRAP: /* trace trap */
522 if (frame.tf_eip == (int)IDTVEC(syscall)) {
523 /*
524 * We've just entered system mode via the
525 * syscall lcall. Continue single stepping
526 * silently until the syscall handler has
527 * saved the flags.
528 */
529 return;
530 }
531 if (frame.tf_eip == (int)IDTVEC(syscall) + 1) {
532 /*
533 * The syscall handler has now saved the
534 * flags. Stop single stepping it.
535 */
536 frame.tf_eflags &= ~PSL_T;
537 return;
538 }
539 /*
540 * Fall through.
541 */
542 case T_BPTFLT:
543 /*
544 * If DDB is enabled, let it handle the debugger trap.
545 * Otherwise, debugger traps "can't happen".
546 */
547 #ifdef DDB
548 if (kdb_trap (type, 0, &frame))
549 return;
550 #endif
551 break;
552
553 #if NISA > 0
554 case T_NMI:
555 #ifdef POWERFAIL_NMI
556 #ifndef TIMER_FREQ
557 # define TIMER_FREQ 1193182
558 #endif
559 handle_powerfail:
560 {
561 static unsigned lastalert = 0;
562
563 if(time_second - lastalert > 10)
564 {
565 log(LOG_WARNING, "NMI: power fail\n");
566 sysbeep(TIMER_FREQ/880, hz);
567 lastalert = time_second;
568 }
569 return;
570 }
571 #else /* !POWERFAIL_NMI */
572 #ifdef DDB
573 /* NMI can be hooked up to a pushbutton for debugging */
574 printf ("NMI ... going to debugger\n");
575 if (kdb_trap (type, 0, &frame))
576 return;
577 #endif /* DDB */
578 /* machine/parity/power fail/"kitchen sink" faults */
579 if (isa_nmi(code) == 0) return;
580 /* FALL THROUGH */
581 #endif /* POWERFAIL_NMI */
582 #endif /* NISA > 0 */
583 }
584
585 trap_fatal(&frame, eva);
586 return;
587 }
588
589 /* Translate fault for emulators (e.g. Linux) */
590 if (*p->p_sysent->sv_transtrap)
591 i = (*p->p_sysent->sv_transtrap)(i, type);
592
593 trapsignal(p, i, ucode);
594
595 #ifdef DEBUG
596 if (type <= MAX_TRAP_MSG) {
597 uprintf("fatal process exception: %s",
598 trap_msg[type]);
599 if ((type == T_PAGEFLT) || (type == T_PROTFLT))
600 uprintf(", fault VA = 0x%lx", (u_long)eva);
601 uprintf("\n");
602 }
603 #endif
604
605 out:
606 userret(p, &frame, sticks);
607 }
608
609 #ifdef notyet
610 /*
611 * This version doesn't allow a page fault to user space while
612 * in the kernel. The rest of the kernel needs to be made "safe"
613 * before this can be used. I think the only things remaining
614 * to be made safe are the iBCS2 code and the process tracing/
615 * debugging code.
616 */
617 static int
618 trap_pfault(frame, usermode, eva)
619 struct trapframe *frame;
620 int usermode;
621 vm_offset_t eva;
622 {
623 vm_offset_t va;
624 struct vmspace *vm = NULL;
625 vm_map_t map = 0;
626 int rv = 0;
627 vm_prot_t ftype;
628 struct proc *p = curproc;
629
630 if (frame->tf_err & PGEX_W)
631 ftype = VM_PROT_READ | VM_PROT_WRITE;
632 else
633 ftype = VM_PROT_READ;
634
635 va = trunc_page(eva);
636 if (va < VM_MIN_KERNEL_ADDRESS) {
637 vm_offset_t v;
638 vm_page_t mpte;
639
640 if (p == NULL ||
641 (!usermode && va < VM_MAXUSER_ADDRESS &&
642 (intr_nesting_level != 0 || curpcb == NULL ||
643 curpcb->pcb_onfault == NULL))) {
644 trap_fatal(frame, eva);
645 return (-1);
646 }
647
648 /*
649 * This is a fault on non-kernel virtual memory.
650 * vm is initialized above to NULL. If curproc is NULL
651 * or curproc->p_vmspace is NULL the fault is fatal.
652 */
653 vm = p->p_vmspace;
654 if (vm == NULL)
655 goto nogo;
656
657 map = &vm->vm_map;
658
659 /*
660 * Keep swapout from messing with us during this
661 * critical time.
662 */
663 ++p->p_lock;
664
665 /*
666 * Grow the stack if necessary
667 */
668 #ifndef VM_STACK
669 if ((caddr_t)va > vm->vm_maxsaddr && va < USRSTACK) {
670 if (!grow(p, va)) {
671 rv = KERN_FAILURE;
672 --p->p_lock;
673 goto nogo;
674 }
675 }
676
677 #else
678 /* grow_stack returns false only if va falls into
679 * a growable stack region and the stack growth
680 * fails. It returns true if va was not within
681 * a growable stack region, or if the stack
682 * growth succeeded.
683 */
684 if (!grow_stack (p, va)) {
685 rv = KERN_FAILURE;
686 --p->p_lock;
687 goto nogo;
688 }
689 #endif
690
691 /* Fault in the user page: */
692 rv = vm_fault(map, va, ftype,
693 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0);
694
695 --p->p_lock;
696 } else {
697 /*
698 * Don't allow user-mode faults in kernel address space.
699 */
700 if (usermode)
701 goto nogo;
702
703 /*
704 * Since we know that kernel virtual address addresses
705 * always have pte pages mapped, we just have to fault
706 * the page.
707 */
708 rv = vm_fault(kernel_map, va, ftype, FALSE);
709 }
710
711 if (rv == KERN_SUCCESS)
712 return (0);
713 nogo:
714 if (!usermode) {
715 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) {
716 frame->tf_eip = (int)curpcb->pcb_onfault;
717 return (0);
718 }
719 trap_fatal(frame, eva);
720 return (-1);
721 }
722
723 /* kludge to pass faulting virtual address to sendsig */
724 frame->tf_err = eva;
725
726 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
727 }
728 #endif
729
730 int
731 trap_pfault(frame, usermode, eva)
732 struct trapframe *frame;
733 int usermode;
734 vm_offset_t eva;
735 {
736 vm_offset_t va;
737 struct vmspace *vm = NULL;
738 vm_map_t map = 0;
739 int rv = 0;
740 vm_prot_t ftype;
741 struct proc *p = curproc;
742
743 va = trunc_page(eva);
744 if (va >= KERNBASE) {
745 /*
746 * Don't allow user-mode faults in kernel address space.
747 * An exception: if the faulting address is the invalid
748 * instruction entry in the IDT, then the Intel Pentium
749 * F00F bug workaround was triggered, and we need to
750 * treat it is as an illegal instruction, and not a page
751 * fault.
752 */
753 #if defined(I586_CPU) && !defined(NO_F00F_HACK)
754 if ((eva == (unsigned int)&t_idt[6]) && has_f00f_bug) {
755 frame->tf_trapno = T_PRIVINFLT;
756 return -2;
757 }
758 #endif
759 if (usermode)
760 goto nogo;
761
762 map = kernel_map;
763 } else {
764 /*
765 * This is a fault on non-kernel virtual memory.
766 * vm is initialized above to NULL. If curproc is NULL
767 * or curproc->p_vmspace is NULL the fault is fatal.
768 */
769 if (p != NULL)
770 vm = p->p_vmspace;
771
772 if (vm == NULL)
773 goto nogo;
774
775 map = &vm->vm_map;
776 }
777
778 if (frame->tf_err & PGEX_W)
779 ftype = VM_PROT_READ | VM_PROT_WRITE;
780 else
781 ftype = VM_PROT_READ;
782
783 if (map != kernel_map) {
784 /*
785 * Keep swapout from messing with us during this
786 * critical time.
787 */
788 ++p->p_lock;
789
790 /*
791 * Grow the stack if necessary
792 */
793 #ifndef VM_STACK
794 if ((caddr_t)va > vm->vm_maxsaddr && va < USRSTACK) {
795 if (!grow(p, va)) {
796 rv = KERN_FAILURE;
797 --p->p_lock;
798 goto nogo;
799 }
800 }
801 #else
802 /* grow_stack returns false only if va falls into
803 * a growable stack region and the stack growth
804 * fails. It returns true if va was not within
805 * a growable stack region, or if the stack
806 * growth succeeded.
807 */
808 if (!grow_stack (p, va)) {
809 rv = KERN_FAILURE;
810 --p->p_lock;
811 goto nogo;
812 }
813 #endif
814
815 /* Fault in the user page: */
816 rv = vm_fault(map, va, ftype,
817 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0);
818
819 --p->p_lock;
820 } else {
821 /*
822 * Don't have to worry about process locking or stacks in the kernel.
823 */
824 rv = vm_fault(map, va, ftype, FALSE);
825 }
826
827 if (rv == KERN_SUCCESS)
828 return (0);
829 nogo:
830 if (!usermode) {
831 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) {
832 frame->tf_eip = (int)curpcb->pcb_onfault;
833 return (0);
834 }
835 trap_fatal(frame, eva);
836 return (-1);
837 }
838
839 /* kludge to pass faulting virtual address to sendsig */
840 frame->tf_err = eva;
841
842 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
843 }
844
845 static void
846 trap_fatal(frame, eva)
847 struct trapframe *frame;
848 vm_offset_t eva;
849 {
850 int code, type, ss, esp;
851 struct soft_segment_descriptor softseg;
852
853 code = frame->tf_err;
854 type = frame->tf_trapno;
855 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg);
856
857 if (type <= MAX_TRAP_MSG)
858 printf("\n\nFatal trap %d: %s while in %s mode\n",
859 type, trap_msg[type],
860 frame->tf_eflags & PSL_VM ? "vm86" :
861 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
862 #ifdef SMP
863 /* three seperate prints in case of a trap on an unmapped page */
864 printf("mp_lock = %08x; ", mp_lock);
865 printf("cpuid = %d; ", cpuid);
866 printf("lapic.id = %08x\n", lapic.id);
867 #endif
868 if (type == T_PAGEFLT) {
869 printf("fault virtual address = 0x%x\n", eva);
870 printf("fault code = %s %s, %s\n",
871 code & PGEX_U ? "user" : "supervisor",
872 code & PGEX_W ? "write" : "read",
873 code & PGEX_P ? "protection violation" : "page not present");
874 }
875 printf("instruction pointer = 0x%x:0x%x\n",
876 frame->tf_cs & 0xffff, frame->tf_eip);
877 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) {
878 ss = frame->tf_ss & 0xffff;
879 esp = frame->tf_esp;
880 } else {
881 ss = GSEL(GDATA_SEL, SEL_KPL);
882 esp = (int)&frame->tf_esp;
883 }
884 printf("stack pointer = 0x%x:0x%x\n", ss, esp);
885 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp);
886 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n",
887 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
888 printf(" = DPL %d, pres %d, def32 %d, gran %d\n",
889 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32,
890 softseg.ssd_gran);
891 printf("processor eflags = ");
892 if (frame->tf_eflags & PSL_T)
893 printf("trace trap, ");
894 if (frame->tf_eflags & PSL_I)
895 printf("interrupt enabled, ");
896 if (frame->tf_eflags & PSL_NT)
897 printf("nested task, ");
898 if (frame->tf_eflags & PSL_RF)
899 printf("resume, ");
900 if (frame->tf_eflags & PSL_VM)
901 printf("vm86, ");
902 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12);
903 printf("current process = ");
904 if (curproc) {
905 printf("%lu (%s)\n",
906 (u_long)curproc->p_pid, curproc->p_comm ?
907 curproc->p_comm : "");
908 } else {
909 printf("Idle\n");
910 }
911 printf("interrupt mask = ");
912 if ((cpl & net_imask) == net_imask)
913 printf("net ");
914 if ((cpl & tty_imask) == tty_imask)
915 printf("tty ");
916 if ((cpl & bio_imask) == bio_imask)
917 printf("bio ");
918 if ((cpl & cam_imask) == cam_imask)
919 printf("cam ");
920 if (cpl == 0)
921 printf("none");
922 #ifdef SMP
923 /**
924 * XXX FIXME:
925 * we probably SHOULD have stopped the other CPUs before now!
926 * another CPU COULD have been touching cpl at this moment...
927 */
928 printf(" <- SMP: XXX");
929 #endif
930 printf("\n");
931
932 #ifdef KDB
933 if (kdb_trap(&psl))
934 return;
935 #endif
936 #ifdef DDB
937 if ((debugger_on_panic || in_Debugger) && kdb_trap(type, 0, frame))
938 return;
939 #endif
940 printf("trap number = %d\n", type);
941 if (type <= MAX_TRAP_MSG)
942 panic(trap_msg[type]);
943 else
944 panic("unknown/reserved trap");
945 }
946
947 /*
948 * Double fault handler. Called when a fault occurs while writing
949 * a frame for a trap/exception onto the stack. This usually occurs
950 * when the stack overflows (such is the case with infinite recursion,
951 * for example).
952 *
953 * XXX Note that the current PTD gets replaced by IdlePTD when the
954 * task switch occurs. This means that the stack that was active at
955 * the time of the double fault is not available at <kstack> unless
956 * the machine was idle when the double fault occurred. The downside
957 * of this is that "trace <ebp>" in ddb won't work.
958 */
959 void
960 dblfault_handler()
961 {
962 printf("\nFatal double fault:\n");
963 printf("eip = 0x%x\n", common_tss.tss_eip);
964 printf("esp = 0x%x\n", common_tss.tss_esp);
965 printf("ebp = 0x%x\n", common_tss.tss_ebp);
966 #ifdef SMP
967 /* three seperate prints in case of a trap on an unmapped page */
968 printf("mp_lock = %08x; ", mp_lock);
969 printf("cpuid = %d; ", cpuid);
970 printf("lapic.id = %08x\n", lapic.id);
971 #endif
972 panic("double fault");
973 }
974
975 /*
976 * Compensate for 386 brain damage (missing URKR).
977 * This is a little simpler than the pagefault handler in trap() because
978 * it the page tables have already been faulted in and high addresses
979 * are thrown out early for other reasons.
980 */
981 int trapwrite(addr)
982 unsigned addr;
983 {
984 struct proc *p;
985 vm_offset_t va;
986 struct vmspace *vm;
987 int rv;
988
989 va = trunc_page((vm_offset_t)addr);
990 /*
991 * XXX - MAX is END. Changed > to >= for temp. fix.
992 */
993 if (va >= VM_MAXUSER_ADDRESS)
994 return (1);
995
996 p = curproc;
997 vm = p->p_vmspace;
998
999 ++p->p_lock;
1000
1001 #ifndef VM_STACK
1002 if ((caddr_t)va >= vm->vm_maxsaddr && va < USRSTACK) {
1003 if (!grow(p, va)) {
1004 --p->p_lock;
1005 return (1);
1006 }
1007 }
1008 #else
1009 if (!grow_stack (p, va)) {
1010 --p->p_lock;
1011 return (1);
1012 }
1013 #endif
1014
1015 /*
1016 * fault the data page
1017 */
1018 rv = vm_fault(&vm->vm_map, va, VM_PROT_READ|VM_PROT_WRITE, VM_FAULT_DIRTY);
1019
1020 --p->p_lock;
1021
1022 if (rv != KERN_SUCCESS)
1023 return 1;
1024
1025 return (0);
1026 }
1027
1028 /*
1029 * System call request from POSIX system call gate interface to kernel.
1030 * Like trap(), argument is call by reference.
1031 */
1032 void
1033 syscall(frame)
1034 struct trapframe frame;
1035 {
1036 caddr_t params;
1037 int i;
1038 struct sysent *callp;
1039 struct proc *p = curproc;
1040 u_quad_t sticks;
1041 int error;
1042 int args[8];
1043 u_int code;
1044
1045 #ifdef DIAGNOSTIC
1046 if (ISPL(frame.tf_cs) != SEL_UPL)
1047 panic("syscall");
1048 #endif
1049 sticks = p->p_sticks;
1050 p->p_md.md_regs = &frame;
1051 params = (caddr_t)frame.tf_esp + sizeof(int);
1052 code = frame.tf_eax;
1053 if (p->p_sysent->sv_prepsyscall) {
1054 (*p->p_sysent->sv_prepsyscall)(&frame, args, &code, ¶ms);
1055 } else {
1056 /*
1057 * Need to check if this is a 32 bit or 64 bit syscall.
1058 */
1059 if (code == SYS_syscall) {
1060 /*
1061 * Code is first argument, followed by actual args.
1062 */
1063 code = fuword(params);
1064 params += sizeof(int);
1065 } else if (code == SYS___syscall) {
1066 /*
1067 * Like syscall, but code is a quad, so as to maintain
1068 * quad alignment for the rest of the arguments.
1069 */
1070 code = fuword(params);
1071 params += sizeof(quad_t);
1072 }
1073 }
1074
1075 if (p->p_sysent->sv_mask)
1076 code &= p->p_sysent->sv_mask;
1077
1078 if (code >= p->p_sysent->sv_size)
1079 callp = &p->p_sysent->sv_table[0];
1080 else
1081 callp = &p->p_sysent->sv_table[code];
1082
1083 if (params && (i = callp->sy_narg * sizeof(int)) &&
1084 (error = copyin(params, (caddr_t)args, (u_int)i))) {
1085 #ifdef KTRACE
1086 if (KTRPOINT(p, KTR_SYSCALL))
1087 ktrsyscall(p->p_tracep, code, callp->sy_narg, args);
1088 #endif
1089 goto bad;
1090 }
1091 #ifdef KTRACE
1092 if (KTRPOINT(p, KTR_SYSCALL))
1093 ktrsyscall(p->p_tracep, code, callp->sy_narg, args);
1094 #endif
1095 p->p_retval[0] = 0;
1096 p->p_retval[1] = frame.tf_edx;
1097
1098 STOPEVENT(p, S_SCE, callp->sy_narg);
1099
1100 error = (*callp->sy_call)(p, args);
1101
1102 switch (error) {
1103
1104 case 0:
1105 /*
1106 * Reinitialize proc pointer `p' as it may be different
1107 * if this is a child returning from fork syscall.
1108 */
1109 p = curproc;
1110 frame.tf_eax = p->p_retval[0];
1111 frame.tf_edx = p->p_retval[1];
1112 frame.tf_eflags &= ~PSL_C;
1113 break;
1114
1115 case ERESTART:
1116 /*
1117 * Reconstruct pc, assuming lcall $X,y is 7 bytes,
1118 * int 0x80 is 2 bytes. We saved this in tf_err.
1119 */
1120 frame.tf_eip -= frame.tf_err;
1121 break;
1122
1123 case EJUSTRETURN:
1124 break;
1125
1126 default:
1127 bad:
1128 if (p->p_sysent->sv_errsize)
1129 if (error >= p->p_sysent->sv_errsize)
1130 error = -1; /* XXX */
1131 else
1132 error = p->p_sysent->sv_errtbl[error];
1133 frame.tf_eax = error;
1134 frame.tf_eflags |= PSL_C;
1135 break;
1136 }
1137
1138 if ((frame.tf_eflags & PSL_T) && !(frame.tf_eflags & PSL_VM)) {
1139 /* Traced syscall. */
1140 frame.tf_eflags &= ~PSL_T;
1141 trapsignal(p, SIGTRAP, 0);
1142 }
1143
1144 userret(p, &frame, sticks);
1145
1146 #ifdef KTRACE
1147 if (KTRPOINT(p, KTR_SYSRET))
1148 ktrsysret(p->p_tracep, code, error, p->p_retval[0]);
1149 #endif
1150
1151 /*
1152 * This works because errno is findable through the
1153 * register set. If we ever support an emulation where this
1154 * is not the case, this code will need to be revisited.
1155 */
1156 STOPEVENT(p, S_SCX, code);
1157
1158 }
1159
1160 /*
1161 * Simplified back end of syscall(), used when returning from fork()
1162 * directly into user mode.
1163 */
1164 void
1165 fork_return(p, frame)
1166 struct proc *p;
1167 struct trapframe frame;
1168 {
1169 frame.tf_eax = 0; /* Child returns zero */
1170 frame.tf_eflags &= ~PSL_C; /* success */
1171 frame.tf_edx = 1;
1172
1173 userret(p, &frame, 0);
1174 #ifdef KTRACE
1175 if (KTRPOINT(p, KTR_SYSRET))
1176 ktrsysret(p->p_tracep, SYS_fork, 0, 0);
1177 #endif
1178 }
Cache object: d803135cf64778662398fe00da97a983
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