1 /* $NetBSD: trap.c,v 1.276 2015/12/16 18:54:03 maxv Exp $ */
2
3 /*-
4 * Copyright (c) 1998, 2000, 2005, 2006, 2007, 2008 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Charles M. Hannum.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 /*-
33 * Copyright (c) 1990 The Regents of the University of California.
34 * All rights reserved.
35 *
36 * This code is derived from software contributed to Berkeley by
37 * the University of Utah, and William Jolitz.
38 *
39 * Redistribution and use in source and binary forms, with or without
40 * modification, are permitted provided that the following conditions
41 * are met:
42 * 1. Redistributions of source code must retain the above copyright
43 * notice, this list of conditions and the following disclaimer.
44 * 2. Redistributions in binary form must reproduce the above copyright
45 * notice, this list of conditions and the following disclaimer in the
46 * documentation and/or other materials provided with the distribution.
47 * 3. Neither the name of the University nor the names of its contributors
48 * may be used to endorse or promote products derived from this software
49 * without specific prior written permission.
50 *
51 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
52 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
53 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
54 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
55 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
56 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
57 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
58 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
59 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
60 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
61 * SUCH DAMAGE.
62 *
63 * @(#)trap.c 7.4 (Berkeley) 5/13/91
64 */
65
66 /*
67 * 386 Trap and System call handling
68 */
69
70 #include <sys/cdefs.h>
71 __KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.276 2015/12/16 18:54:03 maxv Exp $");
72
73 #include "opt_ddb.h"
74 #include "opt_kgdb.h"
75 #include "opt_lockdebug.h"
76 #include "opt_multiprocessor.h"
77 #include "opt_vm86.h"
78 #include "opt_kstack_dr0.h"
79 #include "opt_xen.h"
80 #include "opt_dtrace.h"
81
82 #include <sys/param.h>
83 #include <sys/systm.h>
84 #include <sys/proc.h>
85 #include <sys/acct.h>
86 #include <sys/kauth.h>
87 #include <sys/kernel.h>
88 #include <sys/kmem.h>
89 #include <sys/ras.h>
90 #include <sys/signal.h>
91 #include <sys/syscall.h>
92 #include <sys/cpu.h>
93 #include <sys/ucontext.h>
94
95 #include <uvm/uvm_extern.h>
96
97 #include <machine/cpufunc.h>
98 #include <machine/psl.h>
99 #include <machine/reg.h>
100 #include <machine/trap.h>
101 #include <machine/userret.h>
102 #include <machine/db_machdep.h>
103
104 #include "mca.h"
105 #if NMCA > 0
106 #include <machine/mca_machdep.h>
107 #endif
108
109 #include <x86/nmi.h>
110
111 #include "isa.h"
112
113 #include <sys/kgdb.h>
114
115 #ifdef KDTRACE_HOOKS
116 #include <sys/dtrace_bsd.h>
117
118 /*
119 * This is a hook which is initialised by the dtrace module
120 * to handle traps which might occur during DTrace probe
121 * execution.
122 */
123 dtrace_trap_func_t dtrace_trap_func = NULL;
124
125 dtrace_doubletrap_func_t dtrace_doubletrap_func = NULL;
126 #endif
127
128
129 void trap(struct trapframe *);
130 void trap_tss(struct i386tss *, int, int);
131 void trap_return_fault_return(struct trapframe *) __dead;
132
133 const char * const trap_type[] = {
134 "privileged instruction fault", /* 0 T_PRIVINFLT */
135 "breakpoint trap", /* 1 T_BPTFLT */
136 "arithmetic trap", /* 2 T_ARITHTRAP */
137 "asynchronous system trap", /* 3 T_ASTFLT */
138 "protection fault", /* 4 T_PROTFLT */
139 "trace trap", /* 5 T_TRCTRAP */
140 "page fault", /* 6 T_PAGEFLT */
141 "alignment fault", /* 7 T_ALIGNFLT */
142 "integer divide fault", /* 8 T_DIVIDE */
143 "non-maskable interrupt", /* 9 T_NMI */
144 "overflow trap", /* 10 T_OFLOW */
145 "bounds check fault", /* 11 T_BOUND */
146 "FPU not available fault", /* 12 T_DNA */
147 "double fault", /* 13 T_DOUBLEFLT */
148 "FPU operand fetch fault", /* 14 T_FPOPFLT */
149 "invalid TSS fault", /* 15 T_TSSFLT */
150 "segment not present fault", /* 16 T_SEGNPFLT */
151 "stack fault", /* 17 T_STKFLT */
152 "machine check fault", /* 18 T_MCA */
153 "SSE FP exception", /* 19 T_XMM */
154 "reserved trap", /* 20 T_RESERVED */
155 };
156 int trap_types = __arraycount(trap_type);
157
158 #ifdef DEBUG
159 int trapdebug = 0;
160 #endif
161
162 #define IDTVEC(name) __CONCAT(X, name)
163
164 void
trap_tss(struct i386tss * tss,int trapno,int code)165 trap_tss(struct i386tss *tss, int trapno, int code)
166 {
167 struct trapframe tf;
168
169 tf.tf_gs = tss->tss_gs;
170 tf.tf_fs = tss->tss_fs;
171 tf.tf_es = tss->__tss_es;
172 tf.tf_ds = tss->__tss_ds;
173 tf.tf_edi = tss->__tss_edi;
174 tf.tf_esi = tss->__tss_esi;
175 tf.tf_ebp = tss->tss_ebp;
176 tf.tf_ebx = tss->__tss_ebx;
177 tf.tf_edx = tss->__tss_edx;
178 tf.tf_ecx = tss->__tss_ecx;
179 tf.tf_eax = tss->__tss_eax;
180 tf.tf_trapno = trapno;
181 tf.tf_err = code | TC_TSS;
182 tf.tf_eip = tss->__tss_eip;
183 tf.tf_cs = tss->__tss_cs;
184 tf.tf_eflags = tss->__tss_eflags;
185 tf.tf_esp = tss->tss_esp;
186 tf.tf_ss = tss->__tss_ss;
187 trap(&tf);
188 }
189
190 static void *
onfault_handler(const struct pcb * pcb,const struct trapframe * tf)191 onfault_handler(const struct pcb *pcb, const struct trapframe *tf)
192 {
193 struct onfault_table {
194 uintptr_t start;
195 uintptr_t end;
196 void *handler;
197 };
198 extern const struct onfault_table onfault_table[];
199 const struct onfault_table *p;
200 uintptr_t pc;
201
202 if (pcb->pcb_onfault != NULL) {
203 return pcb->pcb_onfault;
204 }
205
206 pc = tf->tf_eip;
207 for (p = onfault_table; p->start; p++) {
208 if (p->start <= pc && pc < p->end) {
209 return p->handler;
210 }
211 }
212 return NULL;
213 }
214
215 static void
trap_print(const struct trapframe * frame,const lwp_t * l)216 trap_print(const struct trapframe *frame, const lwp_t *l)
217 {
218 const int type = frame->tf_trapno;
219
220 if (frame->tf_trapno < trap_types) {
221 printf("fatal %s", trap_type[type]);
222 } else {
223 printf("unknown trap %d", type);
224 }
225 printf(" in %s mode\n", (type & T_USER) ? "user" : "supervisor");
226
227 printf("trap type %d code %x eip %x cs %x eflags %x cr2 %lx "
228 "ilevel %x esp %x\n",
229 type, frame->tf_err, frame->tf_eip, frame->tf_cs, frame->tf_eflags,
230 (long)rcr2(), curcpu()->ci_ilevel, frame->tf_esp);
231
232 printf("curlwp %p pid %d lid %d lowest kstack %p\n",
233 l, l->l_proc->p_pid, l->l_lid, KSTACK_LOWEST_ADDR(l));
234 }
235
236 static void
check_dr0(void)237 check_dr0(void)
238 {
239 #ifdef KSTACK_CHECK_DR0
240 u_int mask, dr6 = rdr6();
241
242 mask = 1 << 0; /* dr0 */
243 if (dr6 & mask) {
244 panic("trap on DR0: maybe kernel stack overflow\n");
245 #if 0
246 dr6 &= ~mask;
247 ldr6(dr6);
248 return;
249 #endif
250 }
251 #endif
252 }
253
254 /*
255 * trap(frame): exception, fault, and trap interface to BSD kernel.
256 *
257 * This common code is called from assembly language IDT gate entry routines
258 * that prepare a suitable stack frame, and restore this frame after the
259 * exception has been processed. Note that the effect is as if the arguments
260 * were passed call by reference.
261 */
262 void
trap(struct trapframe * frame)263 trap(struct trapframe *frame)
264 {
265 struct lwp *l = curlwp;
266 struct proc *p;
267 struct pcb *pcb;
268 extern char fusubail[], kcopy_fault[], return_address_fault[],
269 IDTVEC(osyscall)[];
270 struct trapframe *vframe;
271 ksiginfo_t ksi;
272 void *onfault;
273 int type, error;
274 uint32_t cr2;
275 bool pfail;
276
277 if (__predict_true(l != NULL)) {
278 pcb = lwp_getpcb(l);
279 p = l->l_proc;
280 } else {
281 /*
282 * this can happen eg. on break points in early on boot.
283 */
284 pcb = NULL;
285 p = NULL;
286 }
287 type = frame->tf_trapno;
288
289 #ifdef DEBUG
290 if (trapdebug) {
291 trap_print(frame, l);
292 }
293 #endif
294 if (type != T_NMI &&
295 !KERNELMODE(frame->tf_cs, frame->tf_eflags)) {
296 type |= T_USER;
297 l->l_md.md_regs = frame;
298 pcb->pcb_cr2 = 0;
299 LWP_CACHE_CREDS(l, p);
300 }
301
302 #ifdef KDTRACE_HOOKS
303 /*
304 * A trap can occur while DTrace executes a probe. Before
305 * executing the probe, DTrace blocks re-scheduling and sets
306 * a flag in its per-cpu flags to indicate that it doesn't
307 * want to fault. On returning from the the probe, the no-fault
308 * flag is cleared and finally re-scheduling is enabled.
309 *
310 * If the DTrace kernel module has registered a trap handler,
311 * call it and if it returns non-zero, assume that it has
312 * handled the trap and modified the trap frame so that this
313 * function can return normally.
314 */
315 if ((type == T_PROTFLT || type == T_PAGEFLT) &&
316 dtrace_trap_func != NULL) {
317 if ((*dtrace_trap_func)(frame, type)) {
318 return;
319 }
320 }
321 #endif
322
323 switch (type) {
324
325 case T_ASTFLT:
326 /*FALLTHROUGH*/
327
328 default:
329 we_re_toast:
330 if (type == T_TRCTRAP)
331 check_dr0();
332 else
333 trap_print(frame, l);
334
335 if (kdb_trap(type, 0, frame))
336 return;
337 if (kgdb_trap(type, frame))
338 return;
339 /*
340 * If this is a breakpoint, don't panic if we're not connected.
341 */
342 if (type == T_BPTFLT && kgdb_disconnected()) {
343 printf("kgdb: ignored %s\n", trap_type[type]);
344 return;
345 }
346 panic("trap");
347 /*NOTREACHED*/
348
349 case T_PROTFLT:
350 case T_SEGNPFLT:
351 case T_ALIGNFLT:
352 case T_TSSFLT:
353 if (p == NULL)
354 goto we_re_toast;
355 /* Check for copyin/copyout fault. */
356 onfault = onfault_handler(pcb, frame);
357 if (onfault != NULL) {
358 copyefault:
359 error = EFAULT;
360 copyfault:
361 frame->tf_eip = (uintptr_t)onfault;
362 frame->tf_eax = error;
363 return;
364 }
365
366 /*
367 * Check for failure during return to user mode.
368 * This can happen loading invalid values into the segment
369 * registers, or during the 'iret' itself.
370 *
371 * We do this by looking at the instruction we faulted on.
372 * The specific instructions we recognize only happen when
373 * returning from a trap, syscall, or interrupt.
374 */
375
376 kernelfault:
377 KSI_INIT_TRAP(&ksi);
378 ksi.ksi_signo = SIGSEGV;
379 ksi.ksi_code = SEGV_ACCERR;
380 ksi.ksi_trap = type;
381
382 switch (*(u_char *)frame->tf_eip) {
383 case 0xcf: /* iret */
384 /*
385 * The 'iret' instruction faulted, so we have the
386 * 'user' registers saved after the kernel %eip:%cs:%fl
387 * of the 'iret' and below that the user %eip:%cs:%fl
388 * the 'iret' was processing.
389 * We must delete the 3 words of kernel return address
390 * from the stack to generate a normal stack frame
391 * (eg for sending a SIGSEGV).
392 */
393 vframe = (void *)((int *)frame + 3);
394 if (KERNELMODE(vframe->tf_cs, vframe->tf_eflags))
395 goto we_re_toast;
396 memmove(vframe, frame,
397 offsetof(struct trapframe, tf_eip));
398 /* Set the faulting address to the user %eip */
399 ksi.ksi_addr = (void *)vframe->tf_eip;
400 break;
401 case 0x8e:
402 switch (*(uint32_t *)frame->tf_eip) {
403 case 0x8e242c8e: /* mov (%esp,%gs), then */
404 case 0x0424648e: /* mov 0x4(%esp),%fs */
405 case 0x0824448e: /* mov 0x8(%esp),%es */
406 case 0x0c245c8e: /* mov 0xc(%esp),%ds */
407 break;
408 default:
409 goto we_re_toast;
410 }
411 /*
412 * We faulted loading one if the user segment registers.
413 * The stack frame containing the user registers is
414 * still valid and is just below the %eip:%cs:%fl of
415 * the kernel fault frame.
416 */
417 vframe = (void *)(&frame->tf_eflags + 1);
418 if (KERNELMODE(vframe->tf_cs, vframe->tf_eflags))
419 goto we_re_toast;
420 /* There is no valid address for the fault */
421 break;
422 default:
423 goto we_re_toast;
424 }
425 /*
426 * We might have faulted trying to execute the
427 * trampoline for a local (nested) signal handler.
428 * Only generate SIGSEGV if the user %cs isn't changed.
429 * (This is only strictly necessary in the 'iret' case.)
430 */
431 if (!pmap_exec_fixup(&p->p_vmspace->vm_map, vframe, pcb)) {
432 /* Save outer frame for any signal return */
433 l->l_md.md_regs = vframe;
434 (*p->p_emul->e_trapsignal)(l, &ksi);
435 }
436 /* Return to user by reloading the user frame */
437 trap_return_fault_return(vframe);
438 /* NOTREACHED */
439
440 case T_PROTFLT|T_USER: /* protection fault */
441 case T_TSSFLT|T_USER:
442 case T_SEGNPFLT|T_USER:
443 case T_STKFLT|T_USER:
444 case T_ALIGNFLT|T_USER:
445 KSI_INIT_TRAP(&ksi);
446
447 ksi.ksi_addr = (void *)rcr2();
448 switch (type) {
449 case T_SEGNPFLT|T_USER:
450 case T_STKFLT|T_USER:
451 ksi.ksi_signo = SIGBUS;
452 ksi.ksi_code = BUS_ADRERR;
453 break;
454 case T_TSSFLT|T_USER:
455 ksi.ksi_signo = SIGBUS;
456 ksi.ksi_code = BUS_OBJERR;
457 break;
458 case T_ALIGNFLT|T_USER:
459 ksi.ksi_signo = SIGBUS;
460 ksi.ksi_code = BUS_ADRALN;
461 break;
462 case T_PROTFLT|T_USER:
463 #ifdef VM86
464 if (frame->tf_eflags & PSL_VM) {
465 vm86_gpfault(l, type & ~T_USER);
466 goto out;
467 }
468 #endif
469 /*
470 * If pmap_exec_fixup does something,
471 * let's retry the trap.
472 */
473 if (pmap_exec_fixup(&p->p_vmspace->vm_map, frame, pcb)){
474 goto out;
475 }
476 ksi.ksi_signo = SIGSEGV;
477 ksi.ksi_code = SEGV_ACCERR;
478 break;
479 default:
480 KASSERT(0);
481 break;
482 }
483 goto trapsignal;
484
485 case T_PRIVINFLT|T_USER: /* privileged instruction fault */
486 case T_FPOPFLT|T_USER: /* coprocessor operand fault */
487 KSI_INIT_TRAP(&ksi);
488 ksi.ksi_signo = SIGILL;
489 ksi.ksi_addr = (void *) frame->tf_eip;
490 switch (type) {
491 case T_PRIVINFLT|T_USER:
492 ksi.ksi_code = ILL_PRVOPC;
493 break;
494 case T_FPOPFLT|T_USER:
495 ksi.ksi_code = ILL_COPROC;
496 break;
497 default:
498 ksi.ksi_code = 0;
499 break;
500 }
501 goto trapsignal;
502
503 case T_ASTFLT|T_USER:
504 /* Allow process switch. */
505 //curcpu()->ci_data.cpu_nast++;
506 if (l->l_pflag & LP_OWEUPC) {
507 l->l_pflag &= ~LP_OWEUPC;
508 ADDUPROF(l);
509 }
510 /* Allow a forced task switch. */
511 if (curcpu()->ci_want_resched) {
512 preempt();
513 }
514 goto out;
515
516 case T_BOUND|T_USER:
517 case T_OFLOW|T_USER:
518 case T_DIVIDE|T_USER:
519 KSI_INIT_TRAP(&ksi);
520 ksi.ksi_signo = SIGFPE;
521 ksi.ksi_addr = (void *)frame->tf_eip;
522 switch (type) {
523 case T_BOUND|T_USER:
524 ksi.ksi_code = FPE_FLTSUB;
525 break;
526 case T_OFLOW|T_USER:
527 ksi.ksi_code = FPE_INTOVF;
528 break;
529 case T_DIVIDE|T_USER:
530 ksi.ksi_code = FPE_INTDIV;
531 break;
532 default:
533 ksi.ksi_code = 0;
534 break;
535 }
536 goto trapsignal;
537
538 case T_PAGEFLT:
539 /* Allow page faults in kernel mode. */
540 if (__predict_false(l == NULL))
541 goto we_re_toast;
542
543 /*
544 * fusubail is used by [fs]uswintr() to prevent page faulting
545 * from inside the profiling interrupt.
546 */
547 onfault = pcb->pcb_onfault;
548 if (onfault == fusubail || onfault == return_address_fault) {
549 goto copyefault;
550 }
551 if (cpu_intr_p() || (l->l_pflag & LP_INTR) != 0) {
552 goto we_re_toast;
553 }
554
555 cr2 = rcr2();
556
557 if (frame->tf_err & PGEX_X) {
558 /* SMEP might have brought us here */
559 if (cr2 > VM_MIN_ADDRESS && cr2 <= VM_MAXUSER_ADDRESS)
560 panic("prevented execution of %p (SMEP)",
561 (void *)cr2);
562 }
563
564 goto faultcommon;
565
566 case T_PAGEFLT|T_USER: { /* page fault */
567 register vaddr_t va;
568 register struct vmspace *vm;
569 register struct vm_map *map;
570 vm_prot_t ftype;
571 extern struct vm_map *kernel_map;
572
573 cr2 = rcr2();
574 faultcommon:
575 vm = p->p_vmspace;
576 if (__predict_false(vm == NULL)) {
577 goto we_re_toast;
578 }
579 pcb->pcb_cr2 = cr2;
580 va = trunc_page((vaddr_t)cr2);
581 /*
582 * It is only a kernel address space fault iff:
583 * 1. (type & T_USER) == 0 and
584 * 2. pcb_onfault not set or
585 * 3. pcb_onfault set but supervisor space fault
586 * The last can occur during an exec() copyin where the
587 * argument space is lazy-allocated.
588 */
589 if (type == T_PAGEFLT && va >= KERNBASE)
590 map = kernel_map;
591 else
592 map = &vm->vm_map;
593 if (frame->tf_err & PGEX_W)
594 ftype = VM_PROT_WRITE;
595 else if (frame->tf_err & PGEX_X)
596 ftype = VM_PROT_EXECUTE;
597 else
598 ftype = VM_PROT_READ;
599
600 #ifdef DIAGNOSTIC
601 if (map == kernel_map && va == 0) {
602 printf("trap: bad kernel access at %lx\n", va);
603 goto we_re_toast;
604 }
605 #endif
606 /* Fault the original page in. */
607 onfault = pcb->pcb_onfault;
608 pcb->pcb_onfault = NULL;
609 error = uvm_fault(map, va, ftype);
610 pcb->pcb_onfault = onfault;
611 if (error == 0) {
612 if (map != kernel_map && (void *)va >= vm->vm_maxsaddr)
613 uvm_grow(p, va);
614
615 pfail = false;
616 while (type == T_PAGEFLT) {
617 /*
618 * we need to switch pmap now if we're in
619 * the middle of copyin/out.
620 *
621 * but we don't need to do so for kcopy as
622 * it never touch userspace.
623 */
624 kpreempt_disable();
625 if (curcpu()->ci_want_pmapload) {
626 onfault = onfault_handler(pcb, frame);
627 if (onfault != kcopy_fault) {
628 pmap_load();
629 }
630 }
631 /*
632 * We need to keep the pmap loaded and
633 * so avoid being preempted until back
634 * into the copy functions. Disable
635 * interrupts at the hardware level before
636 * re-enabling preemption. Interrupts
637 * will be re-enabled by 'iret' when
638 * returning back out of the trap stub.
639 * They'll only be re-enabled when the
640 * program counter is once again in
641 * the copy functions, and so visible
642 * to cpu_kpreempt_exit().
643 */
644 #ifndef XEN
645 x86_disable_intr();
646 #endif
647 l->l_nopreempt--;
648 if (l->l_nopreempt > 0 || !l->l_dopreempt ||
649 pfail) {
650 return;
651 }
652 #ifndef XEN
653 x86_enable_intr();
654 #endif
655 /*
656 * If preemption fails for some reason,
657 * don't retry it. The conditions won't
658 * change under our nose.
659 */
660 pfail = kpreempt(0);
661 }
662 goto out;
663 }
664
665 if (type == T_PAGEFLT) {
666 onfault = onfault_handler(pcb, frame);
667 if (onfault != NULL)
668 goto copyfault;
669 printf("uvm_fault(%p, %#lx, %d) -> %#x\n",
670 map, va, ftype, error);
671 goto kernelfault;
672 }
673
674 KSI_INIT_TRAP(&ksi);
675 ksi.ksi_trap = type & ~T_USER;
676 ksi.ksi_addr = (void *)cr2;
677 switch (error) {
678 case EINVAL:
679 ksi.ksi_signo = SIGBUS;
680 ksi.ksi_code = BUS_ADRERR;
681 break;
682 case EACCES:
683 ksi.ksi_signo = SIGSEGV;
684 ksi.ksi_code = SEGV_ACCERR;
685 error = EFAULT;
686 break;
687 case ENOMEM:
688 ksi.ksi_signo = SIGKILL;
689 printf("UVM: pid %d.%d (%s), uid %d killed: "
690 "out of swap\n", p->p_pid, l->l_lid, p->p_comm,
691 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1);
692 break;
693 default:
694 ksi.ksi_signo = SIGSEGV;
695 ksi.ksi_code = SEGV_MAPERR;
696 break;
697 }
698
699 #ifdef TRAP_SIGDEBUG
700 printf("pid %d.%d (%s): signal %d at eip %x addr %lx "
701 "error %d\n", p->p_pid, l->l_lid, p->p_comm, ksi.ksi_signo,
702 frame->tf_eip, va, error);
703 #endif
704 (*p->p_emul->e_trapsignal)(l, &ksi);
705 break;
706 }
707
708 case T_TRCTRAP:
709 /* Check whether they single-stepped into a lcall. */
710 if (frame->tf_eip == (int)IDTVEC(osyscall))
711 return;
712 if (frame->tf_eip == (int)IDTVEC(osyscall) + 1) {
713 frame->tf_eflags &= ~PSL_T;
714 return;
715 }
716 goto we_re_toast;
717
718 case T_BPTFLT|T_USER: /* bpt instruction fault */
719 case T_TRCTRAP|T_USER: /* trace trap */
720 /*
721 * Don't go single-stepping into a RAS.
722 */
723 if (p->p_raslist == NULL ||
724 (ras_lookup(p, (void *)frame->tf_eip) == (void *)-1)) {
725 KSI_INIT_TRAP(&ksi);
726 ksi.ksi_signo = SIGTRAP;
727 ksi.ksi_trap = type & ~T_USER;
728 if (type == (T_BPTFLT|T_USER))
729 ksi.ksi_code = TRAP_BRKPT;
730 else
731 ksi.ksi_code = TRAP_TRACE;
732 ksi.ksi_addr = (void *)frame->tf_eip;
733 (*p->p_emul->e_trapsignal)(l, &ksi);
734 }
735 break;
736
737 case T_NMI:
738 if (nmi_dispatch(frame))
739 return;
740 /* NMI can be hooked up to a pushbutton for debugging */
741 if (kgdb_trap(type, frame))
742 return;
743 if (kdb_trap(type, 0, frame))
744 return;
745 /* machine/parity/power fail/"kitchen sink" faults */
746 #if NMCA > 0
747 mca_nmi();
748 #endif
749 x86_nmi();
750 }
751
752 if ((type & T_USER) == 0)
753 return;
754 out:
755 userret(l);
756 return;
757 trapsignal:
758 ksi.ksi_trap = type & ~T_USER;
759 (*p->p_emul->e_trapsignal)(l, &ksi);
760 userret(l);
761 }
762
763 /*
764 * startlwp: start of a new LWP.
765 */
766 void
startlwp(void * arg)767 startlwp(void *arg)
768 {
769 ucontext_t *uc = arg;
770 lwp_t *l = curlwp;
771 int error __diagused;
772
773 error = cpu_setmcontext(l, &uc->uc_mcontext, uc->uc_flags);
774 KASSERT(error == 0);
775
776 kmem_free(uc, sizeof(ucontext_t));
777 userret(l);
778 }
779