FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/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: releng/10.2/sys/amd64/amd64/trap.c 284164 2015-06-08 19:44:04Z dim $");
42
43 /*
44 * AMD64 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
54 #include <sys/param.h>
55 #include <sys/bus.h>
56 #include <sys/systm.h>
57 #include <sys/proc.h>
58 #include <sys/pioctl.h>
59 #include <sys/ptrace.h>
60 #include <sys/kdb.h>
61 #include <sys/kernel.h>
62 #include <sys/ktr.h>
63 #include <sys/lock.h>
64 #include <sys/mutex.h>
65 #include <sys/resourcevar.h>
66 #include <sys/signalvar.h>
67 #include <sys/syscall.h>
68 #include <sys/sysctl.h>
69 #include <sys/sysent.h>
70 #include <sys/uio.h>
71 #include <sys/vmmeter.h>
72 #ifdef HWPMC_HOOKS
73 #include <sys/pmckern.h>
74 PMC_SOFT_DEFINE( , , page_fault, all);
75 PMC_SOFT_DEFINE( , , page_fault, read);
76 PMC_SOFT_DEFINE( , , page_fault, write);
77 #endif
78
79 #include <vm/vm.h>
80 #include <vm/vm_param.h>
81 #include <vm/pmap.h>
82 #include <vm/vm_kern.h>
83 #include <vm/vm_map.h>
84 #include <vm/vm_page.h>
85 #include <vm/vm_extern.h>
86
87 #include <machine/cpu.h>
88 #include <machine/intr_machdep.h>
89 #include <x86/mca.h>
90 #include <machine/md_var.h>
91 #include <machine/pcb.h>
92 #ifdef SMP
93 #include <machine/smp.h>
94 #endif
95 #include <machine/tss.h>
96
97 #ifdef KDTRACE_HOOKS
98 #include <sys/dtrace_bsd.h>
99 #endif
100
101 extern void trap(struct trapframe *frame);
102 extern void syscall(struct trapframe *frame);
103 void dblfault_handler(struct trapframe *frame);
104
105 static int trap_pfault(struct trapframe *, int);
106 static void trap_fatal(struct trapframe *, vm_offset_t);
107
108 #define MAX_TRAP_MSG 32
109 static char *trap_msg[] = {
110 "", /* 0 unused */
111 "privileged instruction fault", /* 1 T_PRIVINFLT */
112 "", /* 2 unused */
113 "breakpoint instruction fault", /* 3 T_BPTFLT */
114 "", /* 4 unused */
115 "", /* 5 unused */
116 "arithmetic trap", /* 6 T_ARITHTRAP */
117 "", /* 7 unused */
118 "", /* 8 unused */
119 "general protection fault", /* 9 T_PROTFLT */
120 "trace trap", /* 10 T_TRCTRAP */
121 "", /* 11 unused */
122 "page fault", /* 12 T_PAGEFLT */
123 "", /* 13 unused */
124 "alignment fault", /* 14 T_ALIGNFLT */
125 "", /* 15 unused */
126 "", /* 16 unused */
127 "", /* 17 unused */
128 "integer divide fault", /* 18 T_DIVIDE */
129 "non-maskable interrupt trap", /* 19 T_NMI */
130 "overflow trap", /* 20 T_OFLOW */
131 "FPU bounds check fault", /* 21 T_BOUND */
132 "FPU device not available", /* 22 T_DNA */
133 "double fault", /* 23 T_DOUBLEFLT */
134 "FPU operand fetch fault", /* 24 T_FPOPFLT */
135 "invalid TSS fault", /* 25 T_TSSFLT */
136 "segment not present fault", /* 26 T_SEGNPFLT */
137 "stack fault", /* 27 T_STKFLT */
138 "machine check trap", /* 28 T_MCHK */
139 "SIMD floating-point exception", /* 29 T_XMMFLT */
140 "reserved (unknown) fault", /* 30 T_RESERVED */
141 "", /* 31 unused (reserved) */
142 "DTrace pid return trap", /* 32 T_DTRACE_RET */
143 };
144
145 #ifdef KDB
146 static int kdb_on_nmi = 1;
147 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW,
148 &kdb_on_nmi, 0, "Go to KDB on NMI");
149 TUNABLE_INT("machdep.kdb_on_nmi", &kdb_on_nmi);
150 #endif
151 static int panic_on_nmi = 1;
152 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
153 &panic_on_nmi, 0, "Panic on NMI");
154 TUNABLE_INT("machdep.panic_on_nmi", &panic_on_nmi);
155 static int prot_fault_translation;
156 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW,
157 &prot_fault_translation, 0,
158 "Select signal to deliver on protection fault");
159 static int uprintf_signal;
160 SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW,
161 &uprintf_signal, 0,
162 "Print debugging information on trap signal to ctty");
163
164 /*
165 * Exception, fault, and trap interface to the FreeBSD kernel.
166 * This common code is called from assembly language IDT gate entry
167 * routines that prepare a suitable stack frame, and restore this
168 * frame after the exception has been processed.
169 */
170
171 void
172 trap(struct trapframe *frame)
173 {
174 #ifdef KDTRACE_HOOKS
175 struct reg regs;
176 #endif
177 struct thread *td = curthread;
178 struct proc *p = td->td_proc;
179 int i = 0, ucode = 0, code;
180 u_int type;
181 register_t addr = 0;
182 ksiginfo_t ksi;
183
184 PCPU_INC(cnt.v_trap);
185 type = frame->tf_trapno;
186
187 #ifdef SMP
188 /* Handler for NMI IPIs used for stopping CPUs. */
189 if (type == T_NMI) {
190 if (ipi_nmi_handler() == 0)
191 goto out;
192 }
193 #endif /* SMP */
194
195 #ifdef KDB
196 if (kdb_active) {
197 kdb_reenter();
198 goto out;
199 }
200 #endif
201
202 if (type == T_RESERVED) {
203 trap_fatal(frame, 0);
204 goto out;
205 }
206
207 #ifdef HWPMC_HOOKS
208 /*
209 * CPU PMCs interrupt using an NMI. If the PMC module is
210 * active, pass the 'rip' value to the PMC module's interrupt
211 * handler. A return value of '1' from the handler means that
212 * the NMI was handled by it and we can return immediately.
213 */
214 if (type == T_NMI && pmc_intr &&
215 (*pmc_intr)(PCPU_GET(cpuid), frame))
216 goto out;
217 #endif
218
219 if (type == T_MCHK) {
220 mca_intr();
221 goto out;
222 }
223
224 #ifdef KDTRACE_HOOKS
225 /*
226 * A trap can occur while DTrace executes a probe. Before
227 * executing the probe, DTrace blocks re-scheduling and sets
228 * a flag in its per-cpu flags to indicate that it doesn't
229 * want to fault. On returning from the probe, the no-fault
230 * flag is cleared and finally re-scheduling is enabled.
231 */
232 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
233 goto out;
234 #endif
235
236 if ((frame->tf_rflags & PSL_I) == 0) {
237 /*
238 * Buggy application or kernel code has disabled
239 * interrupts and then trapped. Enabling interrupts
240 * now is wrong, but it is better than running with
241 * interrupts disabled until they are accidentally
242 * enabled later.
243 */
244 if (ISPL(frame->tf_cs) == SEL_UPL)
245 uprintf(
246 "pid %ld (%s): trap %d with interrupts disabled\n",
247 (long)curproc->p_pid, curthread->td_name, type);
248 else if (type != T_NMI && type != T_BPTFLT &&
249 type != T_TRCTRAP) {
250 /*
251 * XXX not quite right, since this may be for a
252 * multiple fault in user mode.
253 */
254 printf("kernel trap %d with interrupts disabled\n",
255 type);
256
257 /*
258 * We shouldn't enable interrupts while holding a
259 * spin lock.
260 */
261 if (td->td_md.md_spinlock_count == 0)
262 enable_intr();
263 }
264 }
265
266 code = frame->tf_err;
267
268 if (ISPL(frame->tf_cs) == SEL_UPL) {
269 /* user trap */
270
271 td->td_pticks = 0;
272 td->td_frame = frame;
273 addr = frame->tf_rip;
274 if (td->td_ucred != p->p_ucred)
275 cred_update_thread(td);
276
277 switch (type) {
278 case T_PRIVINFLT: /* privileged instruction fault */
279 i = SIGILL;
280 ucode = ILL_PRVOPC;
281 break;
282
283 case T_BPTFLT: /* bpt instruction fault */
284 case T_TRCTRAP: /* trace trap */
285 enable_intr();
286 #ifdef KDTRACE_HOOKS
287 if (type == T_BPTFLT) {
288 fill_frame_regs(frame, ®s);
289 if (dtrace_pid_probe_ptr != NULL &&
290 dtrace_pid_probe_ptr(®s) == 0)
291 goto out;
292 }
293 #endif
294 frame->tf_rflags &= ~PSL_T;
295 i = SIGTRAP;
296 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
297 break;
298
299 case T_ARITHTRAP: /* arithmetic trap */
300 ucode = fputrap_x87();
301 if (ucode == -1)
302 goto userout;
303 i = SIGFPE;
304 break;
305
306 case T_PROTFLT: /* general protection fault */
307 i = SIGBUS;
308 ucode = BUS_OBJERR;
309 break;
310 case T_STKFLT: /* stack fault */
311 case T_SEGNPFLT: /* segment not present fault */
312 i = SIGBUS;
313 ucode = BUS_ADRERR;
314 break;
315 case T_TSSFLT: /* invalid TSS fault */
316 i = SIGBUS;
317 ucode = BUS_OBJERR;
318 break;
319 case T_ALIGNFLT:
320 i = SIGBUS;
321 ucode = BUS_ADRALN;
322 break;
323 case T_DOUBLEFLT: /* double fault */
324 default:
325 i = SIGBUS;
326 ucode = BUS_OBJERR;
327 break;
328
329 case T_PAGEFLT: /* page fault */
330 addr = frame->tf_addr;
331 i = trap_pfault(frame, TRUE);
332 if (i == -1)
333 goto userout;
334 if (i == 0)
335 goto user;
336
337 if (i == SIGSEGV)
338 ucode = SEGV_MAPERR;
339 else {
340 if (prot_fault_translation == 0) {
341 /*
342 * Autodetect.
343 * This check also covers the images
344 * without the ABI-tag ELF note.
345 */
346 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD
347 && p->p_osrel >= P_OSREL_SIGSEGV) {
348 i = SIGSEGV;
349 ucode = SEGV_ACCERR;
350 } else {
351 i = SIGBUS;
352 ucode = BUS_PAGE_FAULT;
353 }
354 } else if (prot_fault_translation == 1) {
355 /*
356 * Always compat mode.
357 */
358 i = SIGBUS;
359 ucode = BUS_PAGE_FAULT;
360 } else {
361 /*
362 * Always SIGSEGV mode.
363 */
364 i = SIGSEGV;
365 ucode = SEGV_ACCERR;
366 }
367 }
368 break;
369
370 case T_DIVIDE: /* integer divide fault */
371 ucode = FPE_INTDIV;
372 i = SIGFPE;
373 break;
374
375 #ifdef DEV_ISA
376 case T_NMI:
377 /* machine/parity/power fail/"kitchen sink" faults */
378 if (isa_nmi(code) == 0) {
379 #ifdef KDB
380 /*
381 * NMI can be hooked up to a pushbutton
382 * for debugging.
383 */
384 if (kdb_on_nmi) {
385 printf ("NMI ... going to debugger\n");
386 kdb_trap(type, 0, frame);
387 }
388 #endif /* KDB */
389 goto userout;
390 } else if (panic_on_nmi)
391 panic("NMI indicates hardware failure");
392 break;
393 #endif /* DEV_ISA */
394
395 case T_OFLOW: /* integer overflow fault */
396 ucode = FPE_INTOVF;
397 i = SIGFPE;
398 break;
399
400 case T_BOUND: /* bounds check fault */
401 ucode = FPE_FLTSUB;
402 i = SIGFPE;
403 break;
404
405 case T_DNA:
406 /* transparent fault (due to context switch "late") */
407 KASSERT(PCB_USER_FPU(td->td_pcb),
408 ("kernel FPU ctx has leaked"));
409 fpudna();
410 goto userout;
411
412 case T_FPOPFLT: /* FPU operand fetch fault */
413 ucode = ILL_COPROC;
414 i = SIGILL;
415 break;
416
417 case T_XMMFLT: /* SIMD floating-point exception */
418 ucode = fputrap_sse();
419 if (ucode == -1)
420 goto userout;
421 i = SIGFPE;
422 break;
423 #ifdef KDTRACE_HOOKS
424 case T_DTRACE_RET:
425 enable_intr();
426 fill_frame_regs(frame, ®s);
427 if (dtrace_return_probe_ptr != NULL &&
428 dtrace_return_probe_ptr(®s) == 0)
429 goto out;
430 break;
431 #endif
432 }
433 } else {
434 /* kernel trap */
435
436 KASSERT(cold || td->td_ucred != NULL,
437 ("kernel trap doesn't have ucred"));
438 switch (type) {
439 case T_PAGEFLT: /* page fault */
440 (void) trap_pfault(frame, FALSE);
441 goto out;
442
443 case T_DNA:
444 KASSERT(!PCB_USER_FPU(td->td_pcb),
445 ("Unregistered use of FPU in kernel"));
446 fpudna();
447 goto out;
448
449 case T_ARITHTRAP: /* arithmetic trap */
450 case T_XMMFLT: /* SIMD floating-point exception */
451 case T_FPOPFLT: /* FPU operand fetch fault */
452 /*
453 * For now, supporting kernel handler
454 * registration for FPU traps is overkill.
455 */
456 trap_fatal(frame, 0);
457 goto out;
458
459 case T_STKFLT: /* stack fault */
460 case T_PROTFLT: /* general protection fault */
461 case T_SEGNPFLT: /* segment not present fault */
462 if (td->td_intr_nesting_level != 0)
463 break;
464
465 /*
466 * Invalid segment selectors and out of bounds
467 * %rip's and %rsp's can be set up in user mode.
468 * This causes a fault in kernel mode when the
469 * kernel tries to return to user mode. We want
470 * to get this fault so that we can fix the
471 * problem here and not have to check all the
472 * selectors and pointers when the user changes
473 * them.
474 */
475 if (frame->tf_rip == (long)doreti_iret) {
476 frame->tf_rip = (long)doreti_iret_fault;
477 goto out;
478 }
479 if (frame->tf_rip == (long)ld_ds) {
480 frame->tf_rip = (long)ds_load_fault;
481 goto out;
482 }
483 if (frame->tf_rip == (long)ld_es) {
484 frame->tf_rip = (long)es_load_fault;
485 goto out;
486 }
487 if (frame->tf_rip == (long)ld_fs) {
488 frame->tf_rip = (long)fs_load_fault;
489 goto out;
490 }
491 if (frame->tf_rip == (long)ld_gs) {
492 frame->tf_rip = (long)gs_load_fault;
493 goto out;
494 }
495 if (frame->tf_rip == (long)ld_gsbase) {
496 frame->tf_rip = (long)gsbase_load_fault;
497 goto out;
498 }
499 if (frame->tf_rip == (long)ld_fsbase) {
500 frame->tf_rip = (long)fsbase_load_fault;
501 goto out;
502 }
503 if (curpcb->pcb_onfault != NULL) {
504 frame->tf_rip = (long)curpcb->pcb_onfault;
505 goto out;
506 }
507 break;
508
509 case T_TSSFLT:
510 /*
511 * PSL_NT can be set in user mode and isn't cleared
512 * automatically when the kernel is entered. This
513 * causes a TSS fault when the kernel attempts to
514 * `iret' because the TSS link is uninitialized. We
515 * want to get this fault so that we can fix the
516 * problem here and not every time the kernel is
517 * entered.
518 */
519 if (frame->tf_rflags & PSL_NT) {
520 frame->tf_rflags &= ~PSL_NT;
521 goto out;
522 }
523 break;
524
525 case T_TRCTRAP: /* trace trap */
526 /*
527 * Ignore debug register trace traps due to
528 * accesses in the user's address space, which
529 * can happen under several conditions such as
530 * if a user sets a watchpoint on a buffer and
531 * then passes that buffer to a system call.
532 * We still want to get TRCTRAPS for addresses
533 * in kernel space because that is useful when
534 * debugging the kernel.
535 */
536 if (user_dbreg_trap()) {
537 /*
538 * Reset breakpoint bits because the
539 * processor doesn't
540 */
541 /* XXX check upper bits here */
542 load_dr6(rdr6() & 0xfffffff0);
543 goto out;
544 }
545 /*
546 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
547 */
548 case T_BPTFLT:
549 /*
550 * If KDB is enabled, let it handle the debugger trap.
551 * Otherwise, debugger traps "can't happen".
552 */
553 #ifdef KDB
554 if (kdb_trap(type, 0, frame))
555 goto out;
556 #endif
557 break;
558
559 #ifdef DEV_ISA
560 case T_NMI:
561 /* machine/parity/power fail/"kitchen sink" faults */
562 if (isa_nmi(code) == 0) {
563 #ifdef KDB
564 /*
565 * NMI can be hooked up to a pushbutton
566 * for debugging.
567 */
568 if (kdb_on_nmi) {
569 printf ("NMI ... going to debugger\n");
570 kdb_trap(type, 0, frame);
571 }
572 #endif /* KDB */
573 goto out;
574 } else if (panic_on_nmi == 0)
575 goto out;
576 /* FALLTHROUGH */
577 #endif /* DEV_ISA */
578 }
579
580 trap_fatal(frame, 0);
581 goto out;
582 }
583
584 /* Translate fault for emulators (e.g. Linux) */
585 if (*p->p_sysent->sv_transtrap)
586 i = (*p->p_sysent->sv_transtrap)(i, type);
587
588 ksiginfo_init_trap(&ksi);
589 ksi.ksi_signo = i;
590 ksi.ksi_code = ucode;
591 ksi.ksi_trapno = type;
592 ksi.ksi_addr = (void *)addr;
593 if (uprintf_signal) {
594 uprintf("pid %d comm %s: signal %d err %lx code %d type %d "
595 "addr 0x%lx rsp 0x%lx rip 0x%lx "
596 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n",
597 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr,
598 frame->tf_rsp, frame->tf_rip,
599 fubyte((void *)(frame->tf_rip + 0)),
600 fubyte((void *)(frame->tf_rip + 1)),
601 fubyte((void *)(frame->tf_rip + 2)),
602 fubyte((void *)(frame->tf_rip + 3)),
603 fubyte((void *)(frame->tf_rip + 4)),
604 fubyte((void *)(frame->tf_rip + 5)),
605 fubyte((void *)(frame->tf_rip + 6)),
606 fubyte((void *)(frame->tf_rip + 7)));
607 }
608 KASSERT((read_rflags() & PSL_I) != 0, ("interrupts disabled"));
609 trapsignal(td, &ksi);
610
611 user:
612 userret(td, frame);
613 KASSERT(PCB_USER_FPU(td->td_pcb),
614 ("Return from trap with kernel FPU ctx leaked"));
615 userout:
616 out:
617 return;
618 }
619
620 static int
621 trap_pfault(frame, usermode)
622 struct trapframe *frame;
623 int usermode;
624 {
625 vm_offset_t va;
626 struct vmspace *vm;
627 vm_map_t map;
628 int rv = 0;
629 vm_prot_t ftype;
630 struct thread *td = curthread;
631 struct proc *p = td->td_proc;
632 vm_offset_t eva = frame->tf_addr;
633
634 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) {
635 /*
636 * Due to both processor errata and lazy TLB invalidation when
637 * access restrictions are removed from virtual pages, memory
638 * accesses that are allowed by the physical mapping layer may
639 * nonetheless cause one spurious page fault per virtual page.
640 * When the thread is executing a "no faulting" section that
641 * is bracketed by vm_fault_{disable,enable}_pagefaults(),
642 * every page fault is treated as a spurious page fault,
643 * unless it accesses the same virtual address as the most
644 * recent page fault within the same "no faulting" section.
645 */
646 if (td->td_md.md_spurflt_addr != eva ||
647 (td->td_pflags & TDP_RESETSPUR) != 0) {
648 /*
649 * Do nothing to the TLB. A stale TLB entry is
650 * flushed automatically by a page fault.
651 */
652 td->td_md.md_spurflt_addr = eva;
653 td->td_pflags &= ~TDP_RESETSPUR;
654 return (0);
655 }
656 } else {
657 /*
658 * If we get a page fault while in a critical section, then
659 * it is most likely a fatal kernel page fault. The kernel
660 * is already going to panic trying to get a sleep lock to
661 * do the VM lookup, so just consider it a fatal trap so the
662 * kernel can print out a useful trap message and even get
663 * to the debugger.
664 *
665 * If we get a page fault while holding a non-sleepable
666 * lock, then it is most likely a fatal kernel page fault.
667 * If WITNESS is enabled, then it's going to whine about
668 * bogus LORs with various VM locks, so just skip to the
669 * fatal trap handling directly.
670 */
671 if (td->td_critnest != 0 ||
672 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL,
673 "Kernel page fault") != 0) {
674 trap_fatal(frame, eva);
675 return (-1);
676 }
677 }
678 va = trunc_page(eva);
679 if (va >= VM_MIN_KERNEL_ADDRESS) {
680 /*
681 * Don't allow user-mode faults in kernel address space.
682 */
683 if (usermode)
684 goto nogo;
685
686 map = kernel_map;
687 } else {
688 /*
689 * This is a fault on non-kernel virtual memory. If either
690 * p or p->p_vmspace is NULL, then the fault is fatal.
691 */
692 if (p == NULL || (vm = p->p_vmspace) == NULL)
693 goto nogo;
694
695 map = &vm->vm_map;
696
697 /*
698 * When accessing a usermode address, kernel must be
699 * ready to accept the page fault, and provide a
700 * handling routine. Since accessing the address
701 * without the handler is a bug, do not try to handle
702 * it normally, and panic immediately.
703 */
704 if (!usermode && (td->td_intr_nesting_level != 0 ||
705 curpcb->pcb_onfault == NULL)) {
706 trap_fatal(frame, eva);
707 return (-1);
708 }
709 }
710
711 /*
712 * If the trap was caused by errant bits in the PTE then panic.
713 */
714 if (frame->tf_err & PGEX_RSV) {
715 trap_fatal(frame, eva);
716 return (-1);
717 }
718
719 /*
720 * PGEX_I is defined only if the execute disable bit capability is
721 * supported and enabled.
722 */
723 if (frame->tf_err & PGEX_W)
724 ftype = VM_PROT_WRITE;
725 else if ((frame->tf_err & PGEX_I) && pg_nx != 0)
726 ftype = VM_PROT_EXECUTE;
727 else
728 ftype = VM_PROT_READ;
729
730 if (map != kernel_map) {
731 /*
732 * Keep swapout from messing with us during this
733 * critical time.
734 */
735 PROC_LOCK(p);
736 ++p->p_lock;
737 PROC_UNLOCK(p);
738
739 /* Fault in the user page: */
740 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
741
742 PROC_LOCK(p);
743 --p->p_lock;
744 PROC_UNLOCK(p);
745 } else {
746 /*
747 * Don't have to worry about process locking or stacks in the
748 * kernel.
749 */
750 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
751 }
752 if (rv == KERN_SUCCESS) {
753 #ifdef HWPMC_HOOKS
754 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) {
755 PMC_SOFT_CALL_TF( , , page_fault, all, frame);
756 if (ftype == VM_PROT_READ)
757 PMC_SOFT_CALL_TF( , , page_fault, read,
758 frame);
759 else
760 PMC_SOFT_CALL_TF( , , page_fault, write,
761 frame);
762 }
763 #endif
764 return (0);
765 }
766 nogo:
767 if (!usermode) {
768 if (td->td_intr_nesting_level == 0 &&
769 curpcb->pcb_onfault != NULL) {
770 frame->tf_rip = (long)curpcb->pcb_onfault;
771 return (0);
772 }
773 trap_fatal(frame, eva);
774 return (-1);
775 }
776 return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
777 }
778
779 static void
780 trap_fatal(frame, eva)
781 struct trapframe *frame;
782 vm_offset_t eva;
783 {
784 int code, ss;
785 u_int type;
786 long esp;
787 struct soft_segment_descriptor softseg;
788 char *msg;
789
790 code = frame->tf_err;
791 type = frame->tf_trapno;
792 sdtossd(&gdt[NGDT * PCPU_GET(cpuid) + IDXSEL(frame->tf_cs & 0xffff)],
793 &softseg);
794
795 if (type <= MAX_TRAP_MSG)
796 msg = trap_msg[type];
797 else
798 msg = "UNKNOWN";
799 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg,
800 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
801 #ifdef SMP
802 /* two separate prints in case of a trap on an unmapped page */
803 printf("cpuid = %d; ", PCPU_GET(cpuid));
804 printf("apic id = %02x\n", PCPU_GET(apic_id));
805 #endif
806 if (type == T_PAGEFLT) {
807 printf("fault virtual address = 0x%lx\n", eva);
808 printf("fault code = %s %s %s%s, %s\n",
809 code & PGEX_U ? "user" : "supervisor",
810 code & PGEX_W ? "write" : "read",
811 code & PGEX_I ? "instruction" : "data",
812 code & PGEX_RSV ? " rsv" : "",
813 code & PGEX_P ? "protection violation" : "page not present");
814 }
815 printf("instruction pointer = 0x%lx:0x%lx\n",
816 frame->tf_cs & 0xffff, frame->tf_rip);
817 if (ISPL(frame->tf_cs) == SEL_UPL) {
818 ss = frame->tf_ss & 0xffff;
819 esp = frame->tf_rsp;
820 } else {
821 ss = GSEL(GDATA_SEL, SEL_KPL);
822 esp = (long)&frame->tf_rsp;
823 }
824 printf("stack pointer = 0x%x:0x%lx\n", ss, esp);
825 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp);
826 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n",
827 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
828 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n",
829 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32,
830 softseg.ssd_gran);
831 printf("processor eflags = ");
832 if (frame->tf_rflags & PSL_T)
833 printf("trace trap, ");
834 if (frame->tf_rflags & PSL_I)
835 printf("interrupt enabled, ");
836 if (frame->tf_rflags & PSL_NT)
837 printf("nested task, ");
838 if (frame->tf_rflags & PSL_RF)
839 printf("resume, ");
840 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12);
841 printf("current process = %d (%s)\n",
842 curproc->p_pid, curthread->td_name);
843
844 #ifdef KDB
845 if (debugger_on_panic || kdb_active)
846 if (kdb_trap(type, 0, frame))
847 return;
848 #endif
849 printf("trap number = %d\n", type);
850 if (type <= MAX_TRAP_MSG)
851 panic("%s", trap_msg[type]);
852 else
853 panic("unknown/reserved trap");
854 }
855
856 /*
857 * Double fault handler. Called when a fault occurs while writing
858 * a frame for a trap/exception onto the stack. This usually occurs
859 * when the stack overflows (such is the case with infinite recursion,
860 * for example).
861 */
862 void
863 dblfault_handler(struct trapframe *frame)
864 {
865 #ifdef KDTRACE_HOOKS
866 if (dtrace_doubletrap_func != NULL)
867 (*dtrace_doubletrap_func)();
868 #endif
869 printf("\nFatal double fault\n");
870 printf("rip = 0x%lx\n", frame->tf_rip);
871 printf("rsp = 0x%lx\n", frame->tf_rsp);
872 printf("rbp = 0x%lx\n", frame->tf_rbp);
873 #ifdef SMP
874 /* two separate prints in case of a trap on an unmapped page */
875 printf("cpuid = %d; ", PCPU_GET(cpuid));
876 printf("apic id = %02x\n", PCPU_GET(apic_id));
877 #endif
878 panic("double fault");
879 }
880
881 int
882 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
883 {
884 struct proc *p;
885 struct trapframe *frame;
886 register_t *argp;
887 caddr_t params;
888 int reg, regcnt, error;
889
890 p = td->td_proc;
891 frame = td->td_frame;
892 reg = 0;
893 regcnt = 6;
894
895 params = (caddr_t)frame->tf_rsp + sizeof(register_t);
896 sa->code = frame->tf_rax;
897
898 if (sa->code == SYS_syscall || sa->code == SYS___syscall) {
899 sa->code = frame->tf_rdi;
900 reg++;
901 regcnt--;
902 }
903 if (p->p_sysent->sv_mask)
904 sa->code &= p->p_sysent->sv_mask;
905
906 if (sa->code >= p->p_sysent->sv_size)
907 sa->callp = &p->p_sysent->sv_table[0];
908 else
909 sa->callp = &p->p_sysent->sv_table[sa->code];
910
911 sa->narg = sa->callp->sy_narg;
912 KASSERT(sa->narg <= sizeof(sa->args) / sizeof(sa->args[0]),
913 ("Too many syscall arguments!"));
914 error = 0;
915 argp = &frame->tf_rdi;
916 argp += reg;
917 bcopy(argp, sa->args, sizeof(sa->args[0]) * regcnt);
918 if (sa->narg > regcnt) {
919 KASSERT(params != NULL, ("copyin args with no params!"));
920 error = copyin(params, &sa->args[regcnt],
921 (sa->narg - regcnt) * sizeof(sa->args[0]));
922 }
923
924 if (error == 0) {
925 td->td_retval[0] = 0;
926 td->td_retval[1] = frame->tf_rdx;
927 }
928
929 return (error);
930 }
931
932 #include "../../kern/subr_syscall.c"
933
934 /*
935 * System call handler for native binaries. The trap frame is already
936 * set up by the assembler trampoline and a pointer to it is saved in
937 * td_frame.
938 */
939 void
940 amd64_syscall(struct thread *td, int traced)
941 {
942 struct syscall_args sa;
943 int error;
944 ksiginfo_t ksi;
945
946 #ifdef DIAGNOSTIC
947 if (ISPL(td->td_frame->tf_cs) != SEL_UPL) {
948 panic("syscall");
949 /* NOT REACHED */
950 }
951 #endif
952 error = syscallenter(td, &sa);
953
954 /*
955 * Traced syscall.
956 */
957 if (__predict_false(traced)) {
958 td->td_frame->tf_rflags &= ~PSL_T;
959 ksiginfo_init_trap(&ksi);
960 ksi.ksi_signo = SIGTRAP;
961 ksi.ksi_code = TRAP_TRACE;
962 ksi.ksi_addr = (void *)td->td_frame->tf_rip;
963 trapsignal(td, &ksi);
964 }
965
966 KASSERT(PCB_USER_FPU(td->td_pcb),
967 ("System call %s returing with kernel FPU ctx leaked",
968 syscallname(td->td_proc, sa.code)));
969 KASSERT(td->td_pcb->pcb_save == get_pcb_user_save_td(td),
970 ("System call %s returning with mangled pcb_save",
971 syscallname(td->td_proc, sa.code)));
972
973 syscallret(td, error, &sa);
974
975 /*
976 * If the user-supplied value of %rip is not a canonical
977 * address, then some CPUs will trigger a ring 0 #GP during
978 * the sysret instruction. However, the fault handler would
979 * execute in ring 0 with the user's %gs and %rsp which would
980 * not be safe. Instead, use the full return path which
981 * catches the problem safely.
982 */
983 if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS)
984 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
985 }
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