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/10.0/sys/amd64/amd64/trap.c 256072 2013-10-05 21:22:35Z neel $");
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
100 /*
101 * This is a hook which is initialised by the dtrace module
102 * to handle traps which might occur during DTrace probe
103 * execution.
104 */
105 dtrace_trap_func_t dtrace_trap_func;
106
107 dtrace_doubletrap_func_t dtrace_doubletrap_func;
108
109 /*
110 * This is a hook which is initialised by the systrace module
111 * when it is loaded. This keeps the DTrace syscall provider
112 * implementation opaque.
113 */
114 systrace_probe_func_t systrace_probe_func;
115
116 /*
117 * These hooks are necessary for the pid, usdt and fasttrap providers.
118 */
119 dtrace_fasttrap_probe_ptr_t dtrace_fasttrap_probe_ptr;
120 dtrace_pid_probe_ptr_t dtrace_pid_probe_ptr;
121 dtrace_return_probe_ptr_t dtrace_return_probe_ptr;
122 #endif
123
124 extern void trap(struct trapframe *frame);
125 extern void syscall(struct trapframe *frame);
126 void dblfault_handler(struct trapframe *frame);
127
128 static int trap_pfault(struct trapframe *, int);
129 static void trap_fatal(struct trapframe *, vm_offset_t);
130
131 #define MAX_TRAP_MSG 33
132 static char *trap_msg[] = {
133 "", /* 0 unused */
134 "privileged instruction fault", /* 1 T_PRIVINFLT */
135 "", /* 2 unused */
136 "breakpoint instruction fault", /* 3 T_BPTFLT */
137 "", /* 4 unused */
138 "", /* 5 unused */
139 "arithmetic trap", /* 6 T_ARITHTRAP */
140 "", /* 7 unused */
141 "", /* 8 unused */
142 "general protection fault", /* 9 T_PROTFLT */
143 "trace trap", /* 10 T_TRCTRAP */
144 "", /* 11 unused */
145 "page fault", /* 12 T_PAGEFLT */
146 "", /* 13 unused */
147 "alignment fault", /* 14 T_ALIGNFLT */
148 "", /* 15 unused */
149 "", /* 16 unused */
150 "", /* 17 unused */
151 "integer divide fault", /* 18 T_DIVIDE */
152 "non-maskable interrupt trap", /* 19 T_NMI */
153 "overflow trap", /* 20 T_OFLOW */
154 "FPU bounds check fault", /* 21 T_BOUND */
155 "FPU device not available", /* 22 T_DNA */
156 "double fault", /* 23 T_DOUBLEFLT */
157 "FPU operand fetch fault", /* 24 T_FPOPFLT */
158 "invalid TSS fault", /* 25 T_TSSFLT */
159 "segment not present fault", /* 26 T_SEGNPFLT */
160 "stack fault", /* 27 T_STKFLT */
161 "machine check trap", /* 28 T_MCHK */
162 "SIMD floating-point exception", /* 29 T_XMMFLT */
163 "reserved (unknown) fault", /* 30 T_RESERVED */
164 "", /* 31 unused (reserved) */
165 "DTrace pid return trap", /* 32 T_DTRACE_RET */
166 "DTrace fasttrap probe trap", /* 33 T_DTRACE_PROBE */
167 };
168
169 #ifdef KDB
170 static int kdb_on_nmi = 1;
171 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW,
172 &kdb_on_nmi, 0, "Go to KDB on NMI");
173 TUNABLE_INT("machdep.kdb_on_nmi", &kdb_on_nmi);
174 #endif
175 static int panic_on_nmi = 1;
176 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
177 &panic_on_nmi, 0, "Panic on NMI");
178 TUNABLE_INT("machdep.panic_on_nmi", &panic_on_nmi);
179 static int prot_fault_translation;
180 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW,
181 &prot_fault_translation, 0,
182 "Select signal to deliver on protection fault");
183 static int uprintf_signal;
184 SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW,
185 &uprintf_signal, 0,
186 "Print debugging information on trap signal to ctty");
187
188 /*
189 * Exception, fault, and trap interface to the FreeBSD kernel.
190 * This common code is called from assembly language IDT gate entry
191 * routines that prepare a suitable stack frame, and restore this
192 * frame after the exception has been processed.
193 */
194
195 void
196 trap(struct trapframe *frame)
197 {
198 struct thread *td = curthread;
199 struct proc *p = td->td_proc;
200 int i = 0, ucode = 0, code;
201 u_int type;
202 register_t addr = 0;
203 ksiginfo_t ksi;
204
205 PCPU_INC(cnt.v_trap);
206 type = frame->tf_trapno;
207
208 #ifdef SMP
209 /* Handler for NMI IPIs used for stopping CPUs. */
210 if (type == T_NMI) {
211 if (ipi_nmi_handler() == 0)
212 goto out;
213 }
214 #endif /* SMP */
215
216 #ifdef KDB
217 if (kdb_active) {
218 kdb_reenter();
219 goto out;
220 }
221 #endif
222
223 if (type == T_RESERVED) {
224 trap_fatal(frame, 0);
225 goto out;
226 }
227
228 #ifdef HWPMC_HOOKS
229 /*
230 * CPU PMCs interrupt using an NMI. If the PMC module is
231 * active, pass the 'rip' value to the PMC module's interrupt
232 * handler. A return value of '1' from the handler means that
233 * the NMI was handled by it and we can return immediately.
234 */
235 if (type == T_NMI && pmc_intr &&
236 (*pmc_intr)(PCPU_GET(cpuid), frame))
237 goto out;
238 #endif
239
240 if (type == T_MCHK) {
241 mca_intr();
242 goto out;
243 }
244
245 #ifdef KDTRACE_HOOKS
246 /*
247 * A trap can occur while DTrace executes a probe. Before
248 * executing the probe, DTrace blocks re-scheduling and sets
249 * a flag in it's per-cpu flags to indicate that it doesn't
250 * want to fault. On returning from the probe, the no-fault
251 * flag is cleared and finally re-scheduling is enabled.
252 *
253 * If the DTrace kernel module has registered a trap handler,
254 * call it and if it returns non-zero, assume that it has
255 * handled the trap and modified the trap frame so that this
256 * function can return normally.
257 */
258 if (type == T_DTRACE_PROBE || type == T_DTRACE_RET ||
259 type == T_BPTFLT) {
260 struct reg regs;
261
262 fill_frame_regs(frame, ®s);
263 if (type == T_DTRACE_PROBE &&
264 dtrace_fasttrap_probe_ptr != NULL &&
265 dtrace_fasttrap_probe_ptr(®s) == 0)
266 goto out;
267 else if (type == T_BPTFLT &&
268 dtrace_pid_probe_ptr != NULL &&
269 dtrace_pid_probe_ptr(®s) == 0)
270 goto out;
271 else if (type == T_DTRACE_RET &&
272 dtrace_return_probe_ptr != NULL &&
273 dtrace_return_probe_ptr(®s) == 0)
274 goto out;
275 }
276 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
277 goto out;
278 #endif
279
280 if ((frame->tf_rflags & PSL_I) == 0) {
281 /*
282 * Buggy application or kernel code has disabled
283 * interrupts and then trapped. Enabling interrupts
284 * now is wrong, but it is better than running with
285 * interrupts disabled until they are accidentally
286 * enabled later.
287 */
288 if (ISPL(frame->tf_cs) == SEL_UPL)
289 uprintf(
290 "pid %ld (%s): trap %d with interrupts disabled\n",
291 (long)curproc->p_pid, curthread->td_name, type);
292 else if (type != T_NMI && type != T_BPTFLT &&
293 type != T_TRCTRAP) {
294 /*
295 * XXX not quite right, since this may be for a
296 * multiple fault in user mode.
297 */
298 printf("kernel trap %d with interrupts disabled\n",
299 type);
300
301 /*
302 * We shouldn't enable interrupts while holding a
303 * spin lock.
304 */
305 if (td->td_md.md_spinlock_count == 0)
306 enable_intr();
307 }
308 }
309
310 code = frame->tf_err;
311
312 if (ISPL(frame->tf_cs) == SEL_UPL) {
313 /* user trap */
314
315 td->td_pticks = 0;
316 td->td_frame = frame;
317 addr = frame->tf_rip;
318 if (td->td_ucred != p->p_ucred)
319 cred_update_thread(td);
320
321 switch (type) {
322 case T_PRIVINFLT: /* privileged instruction fault */
323 i = SIGILL;
324 ucode = ILL_PRVOPC;
325 break;
326
327 case T_BPTFLT: /* bpt instruction fault */
328 case T_TRCTRAP: /* trace trap */
329 enable_intr();
330 frame->tf_rflags &= ~PSL_T;
331 i = SIGTRAP;
332 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
333 break;
334
335 case T_ARITHTRAP: /* arithmetic trap */
336 ucode = fputrap_x87();
337 if (ucode == -1)
338 goto userout;
339 i = SIGFPE;
340 break;
341
342 case T_PROTFLT: /* general protection fault */
343 i = SIGBUS;
344 ucode = BUS_OBJERR;
345 break;
346 case T_STKFLT: /* stack fault */
347 case T_SEGNPFLT: /* segment not present fault */
348 i = SIGBUS;
349 ucode = BUS_ADRERR;
350 break;
351 case T_TSSFLT: /* invalid TSS fault */
352 i = SIGBUS;
353 ucode = BUS_OBJERR;
354 break;
355 case T_DOUBLEFLT: /* double fault */
356 default:
357 i = SIGBUS;
358 ucode = BUS_OBJERR;
359 break;
360
361 case T_PAGEFLT: /* page fault */
362 addr = frame->tf_addr;
363 i = trap_pfault(frame, TRUE);
364 if (i == -1)
365 goto userout;
366 if (i == 0)
367 goto user;
368
369 if (i == SIGSEGV)
370 ucode = SEGV_MAPERR;
371 else {
372 if (prot_fault_translation == 0) {
373 /*
374 * Autodetect.
375 * This check also covers the images
376 * without the ABI-tag ELF note.
377 */
378 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD
379 && p->p_osrel >= P_OSREL_SIGSEGV) {
380 i = SIGSEGV;
381 ucode = SEGV_ACCERR;
382 } else {
383 i = SIGBUS;
384 ucode = BUS_PAGE_FAULT;
385 }
386 } else if (prot_fault_translation == 1) {
387 /*
388 * Always compat mode.
389 */
390 i = SIGBUS;
391 ucode = BUS_PAGE_FAULT;
392 } else {
393 /*
394 * Always SIGSEGV mode.
395 */
396 i = SIGSEGV;
397 ucode = SEGV_ACCERR;
398 }
399 }
400 break;
401
402 case T_DIVIDE: /* integer divide fault */
403 ucode = FPE_INTDIV;
404 i = SIGFPE;
405 break;
406
407 #ifdef DEV_ISA
408 case T_NMI:
409 /* machine/parity/power fail/"kitchen sink" faults */
410 if (isa_nmi(code) == 0) {
411 #ifdef KDB
412 /*
413 * NMI can be hooked up to a pushbutton
414 * for debugging.
415 */
416 if (kdb_on_nmi) {
417 printf ("NMI ... going to debugger\n");
418 kdb_trap(type, 0, frame);
419 }
420 #endif /* KDB */
421 goto userout;
422 } else if (panic_on_nmi)
423 panic("NMI indicates hardware failure");
424 break;
425 #endif /* DEV_ISA */
426
427 case T_OFLOW: /* integer overflow fault */
428 ucode = FPE_INTOVF;
429 i = SIGFPE;
430 break;
431
432 case T_BOUND: /* bounds check fault */
433 ucode = FPE_FLTSUB;
434 i = SIGFPE;
435 break;
436
437 case T_DNA:
438 /* transparent fault (due to context switch "late") */
439 KASSERT(PCB_USER_FPU(td->td_pcb),
440 ("kernel FPU ctx has leaked"));
441 fpudna();
442 goto userout;
443
444 case T_FPOPFLT: /* FPU operand fetch fault */
445 ucode = ILL_COPROC;
446 i = SIGILL;
447 break;
448
449 case T_XMMFLT: /* SIMD floating-point exception */
450 ucode = fputrap_sse();
451 if (ucode == -1)
452 goto userout;
453 i = SIGFPE;
454 break;
455 }
456 } else {
457 /* kernel trap */
458
459 KASSERT(cold || td->td_ucred != NULL,
460 ("kernel trap doesn't have ucred"));
461 switch (type) {
462 case T_PAGEFLT: /* page fault */
463 (void) trap_pfault(frame, FALSE);
464 goto out;
465
466 case T_DNA:
467 KASSERT(!PCB_USER_FPU(td->td_pcb),
468 ("Unregistered use of FPU in kernel"));
469 fpudna();
470 goto out;
471
472 case T_ARITHTRAP: /* arithmetic trap */
473 case T_XMMFLT: /* SIMD floating-point exception */
474 case T_FPOPFLT: /* FPU operand fetch fault */
475 /*
476 * XXXKIB for now disable any FPU traps in kernel
477 * handler registration seems to be overkill
478 */
479 trap_fatal(frame, 0);
480 goto out;
481
482 case T_STKFLT: /* stack fault */
483 break;
484
485 case T_PROTFLT: /* general protection fault */
486 case T_SEGNPFLT: /* segment not present fault */
487 if (td->td_intr_nesting_level != 0)
488 break;
489
490 /*
491 * Invalid segment selectors and out of bounds
492 * %rip's and %rsp's can be set up in user mode.
493 * This causes a fault in kernel mode when the
494 * kernel tries to return to user mode. We want
495 * to get this fault so that we can fix the
496 * problem here and not have to check all the
497 * selectors and pointers when the user changes
498 * them.
499 */
500 if (frame->tf_rip == (long)doreti_iret) {
501 frame->tf_rip = (long)doreti_iret_fault;
502 goto out;
503 }
504 if (frame->tf_rip == (long)ld_ds) {
505 frame->tf_rip = (long)ds_load_fault;
506 goto out;
507 }
508 if (frame->tf_rip == (long)ld_es) {
509 frame->tf_rip = (long)es_load_fault;
510 goto out;
511 }
512 if (frame->tf_rip == (long)ld_fs) {
513 frame->tf_rip = (long)fs_load_fault;
514 goto out;
515 }
516 if (frame->tf_rip == (long)ld_gs) {
517 frame->tf_rip = (long)gs_load_fault;
518 goto out;
519 }
520 if (frame->tf_rip == (long)ld_gsbase) {
521 frame->tf_rip = (long)gsbase_load_fault;
522 goto out;
523 }
524 if (frame->tf_rip == (long)ld_fsbase) {
525 frame->tf_rip = (long)fsbase_load_fault;
526 goto out;
527 }
528 if (curpcb->pcb_onfault != NULL) {
529 frame->tf_rip = (long)curpcb->pcb_onfault;
530 goto out;
531 }
532 break;
533
534 case T_TSSFLT:
535 /*
536 * PSL_NT can be set in user mode and isn't cleared
537 * automatically when the kernel is entered. This
538 * causes a TSS fault when the kernel attempts to
539 * `iret' because the TSS link is uninitialized. We
540 * want to get this fault so that we can fix the
541 * problem here and not every time the kernel is
542 * entered.
543 */
544 if (frame->tf_rflags & PSL_NT) {
545 frame->tf_rflags &= ~PSL_NT;
546 goto out;
547 }
548 break;
549
550 case T_TRCTRAP: /* trace trap */
551 /*
552 * Ignore debug register trace traps due to
553 * accesses in the user's address space, which
554 * can happen under several conditions such as
555 * if a user sets a watchpoint on a buffer and
556 * then passes that buffer to a system call.
557 * We still want to get TRCTRAPS for addresses
558 * in kernel space because that is useful when
559 * debugging the kernel.
560 */
561 if (user_dbreg_trap()) {
562 /*
563 * Reset breakpoint bits because the
564 * processor doesn't
565 */
566 /* XXX check upper bits here */
567 load_dr6(rdr6() & 0xfffffff0);
568 goto out;
569 }
570 /*
571 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
572 */
573 case T_BPTFLT:
574 /*
575 * If KDB is enabled, let it handle the debugger trap.
576 * Otherwise, debugger traps "can't happen".
577 */
578 #ifdef KDB
579 if (kdb_trap(type, 0, frame))
580 goto out;
581 #endif
582 break;
583
584 #ifdef DEV_ISA
585 case T_NMI:
586 /* machine/parity/power fail/"kitchen sink" faults */
587 if (isa_nmi(code) == 0) {
588 #ifdef KDB
589 /*
590 * NMI can be hooked up to a pushbutton
591 * for debugging.
592 */
593 if (kdb_on_nmi) {
594 printf ("NMI ... going to debugger\n");
595 kdb_trap(type, 0, frame);
596 }
597 #endif /* KDB */
598 goto out;
599 } else if (panic_on_nmi == 0)
600 goto out;
601 /* FALLTHROUGH */
602 #endif /* DEV_ISA */
603 }
604
605 trap_fatal(frame, 0);
606 goto out;
607 }
608
609 /* Translate fault for emulators (e.g. Linux) */
610 if (*p->p_sysent->sv_transtrap)
611 i = (*p->p_sysent->sv_transtrap)(i, type);
612
613 ksiginfo_init_trap(&ksi);
614 ksi.ksi_signo = i;
615 ksi.ksi_code = ucode;
616 ksi.ksi_trapno = type;
617 ksi.ksi_addr = (void *)addr;
618 if (uprintf_signal) {
619 uprintf("pid %d comm %s: signal %d err %lx code %d type %d "
620 "addr 0x%lx rsp 0x%lx rip 0x%lx "
621 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n",
622 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr,
623 frame->tf_rsp, frame->tf_rip,
624 fubyte((void *)(frame->tf_rip + 0)),
625 fubyte((void *)(frame->tf_rip + 1)),
626 fubyte((void *)(frame->tf_rip + 2)),
627 fubyte((void *)(frame->tf_rip + 3)),
628 fubyte((void *)(frame->tf_rip + 4)),
629 fubyte((void *)(frame->tf_rip + 5)),
630 fubyte((void *)(frame->tf_rip + 6)),
631 fubyte((void *)(frame->tf_rip + 7)));
632 }
633 KASSERT((read_rflags() & PSL_I) != 0, ("interrupts disabled"));
634 trapsignal(td, &ksi);
635
636 user:
637 userret(td, frame);
638 KASSERT(PCB_USER_FPU(td->td_pcb),
639 ("Return from trap with kernel FPU ctx leaked"));
640 userout:
641 out:
642 return;
643 }
644
645 static int
646 trap_pfault(frame, usermode)
647 struct trapframe *frame;
648 int usermode;
649 {
650 vm_offset_t va;
651 struct vmspace *vm;
652 vm_map_t map;
653 int rv = 0;
654 vm_prot_t ftype;
655 struct thread *td = curthread;
656 struct proc *p = td->td_proc;
657 vm_offset_t eva = frame->tf_addr;
658
659 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) {
660 /*
661 * Due to both processor errata and lazy TLB invalidation when
662 * access restrictions are removed from virtual pages, memory
663 * accesses that are allowed by the physical mapping layer may
664 * nonetheless cause one spurious page fault per virtual page.
665 * When the thread is executing a "no faulting" section that
666 * is bracketed by vm_fault_{disable,enable}_pagefaults(),
667 * every page fault is treated as a spurious page fault,
668 * unless it accesses the same virtual address as the most
669 * recent page fault within the same "no faulting" section.
670 */
671 if (td->td_md.md_spurflt_addr != eva ||
672 (td->td_pflags & TDP_RESETSPUR) != 0) {
673 /*
674 * Do nothing to the TLB. A stale TLB entry is
675 * flushed automatically by a page fault.
676 */
677 td->td_md.md_spurflt_addr = eva;
678 td->td_pflags &= ~TDP_RESETSPUR;
679 return (0);
680 }
681 } else {
682 /*
683 * If we get a page fault while in a critical section, then
684 * it is most likely a fatal kernel page fault. The kernel
685 * is already going to panic trying to get a sleep lock to
686 * do the VM lookup, so just consider it a fatal trap so the
687 * kernel can print out a useful trap message and even get
688 * to the debugger.
689 *
690 * If we get a page fault while holding a non-sleepable
691 * lock, then it is most likely a fatal kernel page fault.
692 * If WITNESS is enabled, then it's going to whine about
693 * bogus LORs with various VM locks, so just skip to the
694 * fatal trap handling directly.
695 */
696 if (td->td_critnest != 0 ||
697 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL,
698 "Kernel page fault") != 0) {
699 trap_fatal(frame, eva);
700 return (-1);
701 }
702 }
703 va = trunc_page(eva);
704 if (va >= VM_MIN_KERNEL_ADDRESS) {
705 /*
706 * Don't allow user-mode faults in kernel address space.
707 */
708 if (usermode)
709 goto nogo;
710
711 map = kernel_map;
712 } else {
713 /*
714 * This is a fault on non-kernel virtual memory. If either
715 * p or p->p_vmspace is NULL, then the fault is fatal.
716 */
717 if (p == NULL || (vm = p->p_vmspace) == NULL)
718 goto nogo;
719
720 map = &vm->vm_map;
721
722 /*
723 * When accessing a usermode address, kernel must be
724 * ready to accept the page fault, and provide a
725 * handling routine. Since accessing the address
726 * without the handler is a bug, do not try to handle
727 * it normally, and panic immediately.
728 */
729 if (!usermode && (td->td_intr_nesting_level != 0 ||
730 curpcb->pcb_onfault == NULL)) {
731 trap_fatal(frame, eva);
732 return (-1);
733 }
734 }
735
736 /*
737 * If the trap was caused by errant bits in the PTE then panic.
738 */
739 if (frame->tf_err & PGEX_RSV) {
740 trap_fatal(frame, eva);
741 return (-1);
742 }
743
744 /*
745 * PGEX_I is defined only if the execute disable bit capability is
746 * supported and enabled.
747 */
748 if (frame->tf_err & PGEX_W)
749 ftype = VM_PROT_WRITE;
750 else if ((frame->tf_err & PGEX_I) && pg_nx != 0)
751 ftype = VM_PROT_EXECUTE;
752 else
753 ftype = VM_PROT_READ;
754
755 if (map != kernel_map) {
756 /*
757 * Keep swapout from messing with us during this
758 * critical time.
759 */
760 PROC_LOCK(p);
761 ++p->p_lock;
762 PROC_UNLOCK(p);
763
764 /* Fault in the user page: */
765 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
766
767 PROC_LOCK(p);
768 --p->p_lock;
769 PROC_UNLOCK(p);
770 } else {
771 /*
772 * Don't have to worry about process locking or stacks in the
773 * kernel.
774 */
775 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
776 }
777 if (rv == KERN_SUCCESS) {
778 #ifdef HWPMC_HOOKS
779 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) {
780 PMC_SOFT_CALL_TF( , , page_fault, all, frame);
781 if (ftype == VM_PROT_READ)
782 PMC_SOFT_CALL_TF( , , page_fault, read,
783 frame);
784 else
785 PMC_SOFT_CALL_TF( , , page_fault, write,
786 frame);
787 }
788 #endif
789 return (0);
790 }
791 nogo:
792 if (!usermode) {
793 if (td->td_intr_nesting_level == 0 &&
794 curpcb->pcb_onfault != NULL) {
795 frame->tf_rip = (long)curpcb->pcb_onfault;
796 return (0);
797 }
798 trap_fatal(frame, eva);
799 return (-1);
800 }
801 return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
802 }
803
804 static void
805 trap_fatal(frame, eva)
806 struct trapframe *frame;
807 vm_offset_t eva;
808 {
809 int code, ss;
810 u_int type;
811 long esp;
812 struct soft_segment_descriptor softseg;
813 char *msg;
814
815 code = frame->tf_err;
816 type = frame->tf_trapno;
817 sdtossd(&gdt[NGDT * PCPU_GET(cpuid) + IDXSEL(frame->tf_cs & 0xffff)],
818 &softseg);
819
820 if (type <= MAX_TRAP_MSG)
821 msg = trap_msg[type];
822 else
823 msg = "UNKNOWN";
824 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg,
825 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
826 #ifdef SMP
827 /* two separate prints in case of a trap on an unmapped page */
828 printf("cpuid = %d; ", PCPU_GET(cpuid));
829 printf("apic id = %02x\n", PCPU_GET(apic_id));
830 #endif
831 if (type == T_PAGEFLT) {
832 printf("fault virtual address = 0x%lx\n", eva);
833 printf("fault code = %s %s %s%s, %s\n",
834 code & PGEX_U ? "user" : "supervisor",
835 code & PGEX_W ? "write" : "read",
836 code & PGEX_I ? "instruction" : "data",
837 code & PGEX_RSV ? " rsv" : "",
838 code & PGEX_P ? "protection violation" : "page not present");
839 }
840 printf("instruction pointer = 0x%lx:0x%lx\n",
841 frame->tf_cs & 0xffff, frame->tf_rip);
842 if (ISPL(frame->tf_cs) == SEL_UPL) {
843 ss = frame->tf_ss & 0xffff;
844 esp = frame->tf_rsp;
845 } else {
846 ss = GSEL(GDATA_SEL, SEL_KPL);
847 esp = (long)&frame->tf_rsp;
848 }
849 printf("stack pointer = 0x%x:0x%lx\n", ss, esp);
850 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp);
851 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n",
852 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
853 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n",
854 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32,
855 softseg.ssd_gran);
856 printf("processor eflags = ");
857 if (frame->tf_rflags & PSL_T)
858 printf("trace trap, ");
859 if (frame->tf_rflags & PSL_I)
860 printf("interrupt enabled, ");
861 if (frame->tf_rflags & PSL_NT)
862 printf("nested task, ");
863 if (frame->tf_rflags & PSL_RF)
864 printf("resume, ");
865 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12);
866 printf("current process = ");
867 if (curproc) {
868 printf("%lu (%s)\n",
869 (u_long)curproc->p_pid, curthread->td_name ?
870 curthread->td_name : "");
871 } else {
872 printf("Idle\n");
873 }
874
875 #ifdef KDB
876 if (debugger_on_panic || kdb_active)
877 if (kdb_trap(type, 0, frame))
878 return;
879 #endif
880 printf("trap number = %d\n", type);
881 if (type <= MAX_TRAP_MSG)
882 panic("%s", trap_msg[type]);
883 else
884 panic("unknown/reserved trap");
885 }
886
887 /*
888 * Double fault handler. Called when a fault occurs while writing
889 * a frame for a trap/exception onto the stack. This usually occurs
890 * when the stack overflows (such is the case with infinite recursion,
891 * for example).
892 */
893 void
894 dblfault_handler(struct trapframe *frame)
895 {
896 #ifdef KDTRACE_HOOKS
897 if (dtrace_doubletrap_func != NULL)
898 (*dtrace_doubletrap_func)();
899 #endif
900 printf("\nFatal double fault\n");
901 printf("rip = 0x%lx\n", frame->tf_rip);
902 printf("rsp = 0x%lx\n", frame->tf_rsp);
903 printf("rbp = 0x%lx\n", frame->tf_rbp);
904 #ifdef SMP
905 /* two separate prints in case of a trap on an unmapped page */
906 printf("cpuid = %d; ", PCPU_GET(cpuid));
907 printf("apic id = %02x\n", PCPU_GET(apic_id));
908 #endif
909 panic("double fault");
910 }
911
912 int
913 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
914 {
915 struct proc *p;
916 struct trapframe *frame;
917 register_t *argp;
918 caddr_t params;
919 int reg, regcnt, error;
920
921 p = td->td_proc;
922 frame = td->td_frame;
923 reg = 0;
924 regcnt = 6;
925
926 params = (caddr_t)frame->tf_rsp + sizeof(register_t);
927 sa->code = frame->tf_rax;
928
929 if (sa->code == SYS_syscall || sa->code == SYS___syscall) {
930 sa->code = frame->tf_rdi;
931 reg++;
932 regcnt--;
933 }
934 if (p->p_sysent->sv_mask)
935 sa->code &= p->p_sysent->sv_mask;
936
937 if (sa->code >= p->p_sysent->sv_size)
938 sa->callp = &p->p_sysent->sv_table[0];
939 else
940 sa->callp = &p->p_sysent->sv_table[sa->code];
941
942 sa->narg = sa->callp->sy_narg;
943 KASSERT(sa->narg <= sizeof(sa->args) / sizeof(sa->args[0]),
944 ("Too many syscall arguments!"));
945 error = 0;
946 argp = &frame->tf_rdi;
947 argp += reg;
948 bcopy(argp, sa->args, sizeof(sa->args[0]) * regcnt);
949 if (sa->narg > regcnt) {
950 KASSERT(params != NULL, ("copyin args with no params!"));
951 error = copyin(params, &sa->args[regcnt],
952 (sa->narg - regcnt) * sizeof(sa->args[0]));
953 }
954
955 if (error == 0) {
956 td->td_retval[0] = 0;
957 td->td_retval[1] = frame->tf_rdx;
958 }
959
960 return (error);
961 }
962
963 #include "../../kern/subr_syscall.c"
964
965 /*
966 * System call handler for native binaries. The trap frame is already
967 * set up by the assembler trampoline and a pointer to it is saved in
968 * td_frame.
969 */
970 void
971 amd64_syscall(struct thread *td, int traced)
972 {
973 struct syscall_args sa;
974 int error;
975 ksiginfo_t ksi;
976
977 #ifdef DIAGNOSTIC
978 if (ISPL(td->td_frame->tf_cs) != SEL_UPL) {
979 panic("syscall");
980 /* NOT REACHED */
981 }
982 #endif
983 error = syscallenter(td, &sa);
984
985 /*
986 * Traced syscall.
987 */
988 if (__predict_false(traced)) {
989 td->td_frame->tf_rflags &= ~PSL_T;
990 ksiginfo_init_trap(&ksi);
991 ksi.ksi_signo = SIGTRAP;
992 ksi.ksi_code = TRAP_TRACE;
993 ksi.ksi_addr = (void *)td->td_frame->tf_rip;
994 trapsignal(td, &ksi);
995 }
996
997 KASSERT(PCB_USER_FPU(td->td_pcb),
998 ("System call %s returing with kernel FPU ctx leaked",
999 syscallname(td->td_proc, sa.code)));
1000 KASSERT(td->td_pcb->pcb_save == get_pcb_user_save_td(td),
1001 ("System call %s returning with mangled pcb_save",
1002 syscallname(td->td_proc, sa.code)));
1003
1004 syscallret(td, error, &sa);
1005
1006 /*
1007 * If the user-supplied value of %rip is not a canonical
1008 * address, then some CPUs will trigger a ring 0 #GP during
1009 * the sysret instruction. However, the fault handler would
1010 * execute in ring 0 with the user's %gs and %rsp which would
1011 * not be safe. Instead, use the full return path which
1012 * catches the problem safely.
1013 */
1014 if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS)
1015 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
1016 }
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