1 /* $NetBSD: fault.c,v 1.45 2003/11/20 14:44:36 scw Exp $ */
2
3 /*-
4 * Copyright 2004 Olivier Houchard
5 * Copyright 2003 Wasabi Systems, Inc.
6 * All rights reserved.
7 *
8 * Written by Steve C. Woodford for Wasabi Systems, Inc.
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 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed for the NetBSD Project by
21 * Wasabi Systems, Inc.
22 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
23 * or promote products derived from this software without specific prior
24 * written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38 /*-
39 * Copyright (c) 1994-1997 Mark Brinicombe.
40 * Copyright (c) 1994 Brini.
41 * All rights reserved.
42 *
43 * This code is derived from software written for Brini by Mark Brinicombe
44 *
45 * Redistribution and use in source and binary forms, with or without
46 * modification, are permitted provided that the following conditions
47 * are met:
48 * 1. Redistributions of source code must retain the above copyright
49 * notice, this list of conditions and the following disclaimer.
50 * 2. Redistributions in binary form must reproduce the above copyright
51 * notice, this list of conditions and the following disclaimer in the
52 * documentation and/or other materials provided with the distribution.
53 * 3. All advertising materials mentioning features or use of this software
54 * must display the following acknowledgement:
55 * This product includes software developed by Brini.
56 * 4. The name of the company nor the name of the author may be used to
57 * endorse or promote products derived from this software without specific
58 * prior written permission.
59 *
60 * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED
61 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
62 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
63 * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
64 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
65 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
66 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
70 * SUCH DAMAGE.
71 *
72 * RiscBSD kernel project
73 *
74 * fault.c
75 *
76 * Fault handlers
77 *
78 * Created : 28/11/94
79 */
80
81
82 #include <sys/cdefs.h>
83 __FBSDID("$FreeBSD: stable/10/sys/arm/arm/trap.c 335557 2018-06-22 11:16:17Z avg $");
84
85 #include <sys/param.h>
86 #include <sys/systm.h>
87 #include <sys/proc.h>
88 #include <sys/lock.h>
89 #include <sys/mutex.h>
90 #include <sys/signalvar.h>
91
92 #include <vm/vm.h>
93 #include <vm/pmap.h>
94 #include <vm/vm_kern.h>
95 #include <vm/vm_map.h>
96 #include <vm/vm_extern.h>
97
98 #include <machine/acle-compat.h>
99 #include <machine/cpu.h>
100 #include <machine/frame.h>
101 #include <machine/machdep.h>
102 #include <machine/pcb.h>
103 #include <machine/vmparam.h>
104
105 #ifdef KDB
106 #include <sys/kdb.h>
107 #endif
108
109 extern char fusubailout[];
110
111 #ifdef DEBUG
112 int last_fault_code; /* For the benefit of pmap_fault_fixup() */
113 #endif
114
115 struct ksig {
116 int signb;
117 u_long code;
118 };
119 struct data_abort {
120 int (*func)(struct trapframe *, u_int, u_int, struct thread *,
121 struct ksig *);
122 const char *desc;
123 };
124
125 static int dab_fatal(struct trapframe *, u_int, u_int, struct thread *,
126 struct ksig *);
127 static int dab_align(struct trapframe *, u_int, u_int, struct thread *,
128 struct ksig *);
129 static int dab_buserr(struct trapframe *, u_int, u_int, struct thread *,
130 struct ksig *);
131 static void prefetch_abort_handler(struct trapframe *);
132
133 static const struct data_abort data_aborts[] = {
134 {dab_fatal, "Vector Exception"},
135 {dab_align, "Alignment Fault 1"},
136 {dab_fatal, "Terminal Exception"},
137 {dab_align, "Alignment Fault 3"},
138 {dab_buserr, "External Linefetch Abort (S)"},
139 {NULL, "Translation Fault (S)"},
140 #if (ARM_MMU_V6 + ARM_MMU_V7) != 0
141 {NULL, "Translation Flag Fault"},
142 #else
143 {dab_buserr, "External Linefetch Abort (P)"},
144 #endif
145 {NULL, "Translation Fault (P)"},
146 {dab_buserr, "External Non-Linefetch Abort (S)"},
147 {NULL, "Domain Fault (S)"},
148 {dab_buserr, "External Non-Linefetch Abort (P)"},
149 {NULL, "Domain Fault (P)"},
150 {dab_buserr, "External Translation Abort (L1)"},
151 {NULL, "Permission Fault (S)"},
152 {dab_buserr, "External Translation Abort (L2)"},
153 {NULL, "Permission Fault (P)"}
154 };
155
156 /* Determine if a fault came from user mode */
157 #define TRAP_USERMODE(tf) ((tf->tf_spsr & PSR_MODE) == PSR_USR32_MODE)
158
159 /* Determine if 'x' is a permission fault */
160 #define IS_PERMISSION_FAULT(x) \
161 (((1 << ((x) & FAULT_TYPE_MASK)) & \
162 ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0)
163
164 static __inline void
call_trapsignal(struct thread * td,int sig,u_long code)165 call_trapsignal(struct thread *td, int sig, u_long code)
166 {
167 ksiginfo_t ksi;
168
169 ksiginfo_init_trap(&ksi);
170 ksi.ksi_signo = sig;
171 ksi.ksi_code = (int)code;
172 trapsignal(td, &ksi);
173 }
174
175 void
abort_handler(struct trapframe * tf,int type)176 abort_handler(struct trapframe *tf, int type)
177 {
178 struct vm_map *map;
179 struct pcb *pcb;
180 struct thread *td;
181 u_int user, far, fsr;
182 vm_prot_t ftype;
183 void *onfault;
184 vm_offset_t va;
185 int error = 0;
186 struct ksig ksig;
187 struct proc *p;
188
189 if (type == 1)
190 return (prefetch_abort_handler(tf));
191
192 /* Grab FAR/FSR before enabling interrupts */
193 far = cpu_faultaddress();
194 fsr = cpu_faultstatus();
195 #if 0
196 printf("data abort: fault address=%p (from pc=%p lr=%p)\n",
197 (void*)far, (void*)tf->tf_pc, (void*)tf->tf_svc_lr);
198 #endif
199
200 /* Update vmmeter statistics */
201 #if 0
202 vmexp.traps++;
203 #endif
204
205 td = curthread;
206 p = td->td_proc;
207
208 PCPU_INC(cnt.v_trap);
209 /* Data abort came from user mode? */
210 user = TRAP_USERMODE(tf);
211
212 if (user) {
213 td->td_pticks = 0;
214 td->td_frame = tf;
215 if (td->td_ucred != td->td_proc->p_ucred)
216 cred_update_thread(td);
217
218 }
219 /* Grab the current pcb */
220 pcb = td->td_pcb;
221 /* Re-enable interrupts if they were enabled previously */
222 if (td->td_md.md_spinlock_count == 0) {
223 if (__predict_true(tf->tf_spsr & PSR_I) == 0)
224 enable_interrupts(PSR_I);
225 if (__predict_true(tf->tf_spsr & PSR_F) == 0)
226 enable_interrupts(PSR_F);
227 }
228
229
230 /* Invoke the appropriate handler, if necessary */
231 if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) {
232 if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far,
233 td, &ksig)) {
234 goto do_trapsignal;
235 }
236 goto out;
237 }
238
239 /*
240 * At this point, we're dealing with one of the following data aborts:
241 *
242 * FAULT_TRANS_S - Translation -- Section
243 * FAULT_TRANS_P - Translation -- Page
244 * FAULT_DOMAIN_S - Domain -- Section
245 * FAULT_DOMAIN_P - Domain -- Page
246 * FAULT_PERM_S - Permission -- Section
247 * FAULT_PERM_P - Permission -- Page
248 *
249 * These are the main virtual memory-related faults signalled by
250 * the MMU.
251 */
252
253 /* fusubailout is used by [fs]uswintr to avoid page faulting */
254 if (__predict_false(pcb->pcb_onfault == fusubailout)) {
255 tf->tf_r0 = EFAULT;
256 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault;
257 return;
258 }
259
260 /*
261 * Make sure the Program Counter is sane. We could fall foul of
262 * someone executing Thumb code, in which case the PC might not
263 * be word-aligned. This would cause a kernel alignment fault
264 * further down if we have to decode the current instruction.
265 * XXX: It would be nice to be able to support Thumb at some point.
266 */
267 if (__predict_false((tf->tf_pc & 3) != 0)) {
268 if (user) {
269 /*
270 * Give the user an illegal instruction signal.
271 */
272 /* Deliver a SIGILL to the process */
273 ksig.signb = SIGILL;
274 ksig.code = 0;
275 goto do_trapsignal;
276 }
277
278 /*
279 * The kernel never executes Thumb code.
280 */
281 printf("\ndata_abort_fault: Misaligned Kernel-mode "
282 "Program Counter\n");
283 dab_fatal(tf, fsr, far, td, &ksig);
284 }
285
286 va = trunc_page((vm_offset_t)far);
287
288 /*
289 * It is only a kernel address space fault iff:
290 * 1. user == 0 and
291 * 2. pcb_onfault not set or
292 * 3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction.
293 */
294 if (user == 0 && (va >= VM_MIN_KERNEL_ADDRESS ||
295 (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) &&
296 __predict_true((pcb->pcb_onfault == NULL ||
297 (ReadWord(tf->tf_pc) & 0x05200000) != 0x04200000))) {
298 map = kernel_map;
299
300 /* Was the fault due to the FPE/IPKDB ? */
301 if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) {
302
303 /*
304 * Force exit via userret()
305 * This is necessary as the FPE is an extension to
306 * userland that actually runs in a priveledged mode
307 * but uses USR mode permissions for its accesses.
308 */
309 user = 1;
310 ksig.signb = SIGSEGV;
311 ksig.code = 0;
312 goto do_trapsignal;
313 }
314 } else {
315 map = &td->td_proc->p_vmspace->vm_map;
316 }
317
318 /*
319 * We need to know whether the page should be mapped as R or R/W. On
320 * armv6 and later the fault status register indicates whether the
321 * access was a read or write. Prior to armv6, we know that a
322 * permission fault can only be the result of a write to a read-only
323 * location, so we can deal with those quickly. Otherwise we need to
324 * disassemble the faulting instruction to determine if it was a write.
325 */
326 #if __ARM_ARCH >= 6
327 ftype = (fsr & FAULT_WNR) ? VM_PROT_READ | VM_PROT_WRITE : VM_PROT_READ;
328 #else
329 if (IS_PERMISSION_FAULT(fsr))
330 ftype = VM_PROT_WRITE;
331 else {
332 u_int insn = ReadWord(tf->tf_pc);
333
334 if (((insn & 0x0c100000) == 0x04000000) || /* STR/STRB */
335 ((insn & 0x0e1000b0) == 0x000000b0) || /* STRH/STRD */
336 ((insn & 0x0a100000) == 0x08000000)) { /* STM/CDT */
337 ftype = VM_PROT_WRITE;
338 } else {
339 if ((insn & 0x0fb00ff0) == 0x01000090) /* SWP */
340 ftype = VM_PROT_READ | VM_PROT_WRITE;
341 else
342 ftype = VM_PROT_READ;
343 }
344 }
345 #endif
346
347 /*
348 * See if the fault is as a result of ref/mod emulation,
349 * or domain mismatch.
350 */
351 #ifdef DEBUG
352 last_fault_code = fsr;
353 #endif
354 if (pmap_fault_fixup(vmspace_pmap(td->td_proc->p_vmspace), va, ftype,
355 user)) {
356 goto out;
357 }
358
359 onfault = pcb->pcb_onfault;
360 pcb->pcb_onfault = NULL;
361 if (map != kernel_map) {
362 PROC_LOCK(p);
363 p->p_lock++;
364 PROC_UNLOCK(p);
365 }
366 error = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
367 pcb->pcb_onfault = onfault;
368
369 if (map != kernel_map) {
370 PROC_LOCK(p);
371 p->p_lock--;
372 PROC_UNLOCK(p);
373 }
374 if (__predict_true(error == 0))
375 goto out;
376 if (user == 0) {
377 if (pcb->pcb_onfault) {
378 tf->tf_r0 = error;
379 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault;
380 return;
381 }
382
383 printf("\nvm_fault(%p, %x, %x, 0) -> %x\n", map, va, ftype,
384 error);
385 dab_fatal(tf, fsr, far, td, &ksig);
386 }
387
388
389 if (error == ENOMEM) {
390 printf("VM: pid %d (%s), uid %d killed: "
391 "out of swap\n", td->td_proc->p_pid, td->td_name,
392 (td->td_proc->p_ucred) ?
393 td->td_proc->p_ucred->cr_uid : -1);
394 ksig.signb = SIGKILL;
395 } else {
396 ksig.signb = SIGSEGV;
397 }
398 ksig.code = 0;
399 do_trapsignal:
400 call_trapsignal(td, ksig.signb, ksig.code);
401 out:
402 /* If returning to user mode, make sure to invoke userret() */
403 if (user)
404 userret(td, tf);
405 }
406
407 /*
408 * dab_fatal() handles the following data aborts:
409 *
410 * FAULT_WRTBUF_0 - Vector Exception
411 * FAULT_WRTBUF_1 - Terminal Exception
412 *
413 * We should never see these on a properly functioning system.
414 *
415 * This function is also called by the other handlers if they
416 * detect a fatal problem.
417 *
418 * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort.
419 */
420 static int
dab_fatal(struct trapframe * tf,u_int fsr,u_int far,struct thread * td,struct ksig * ksig)421 dab_fatal(struct trapframe *tf, u_int fsr, u_int far, struct thread *td,
422 struct ksig *ksig)
423 {
424 const char *mode;
425 #ifdef KDB
426 bool handled;
427 #endif
428
429 #ifdef KDB
430 if (kdb_active) {
431 kdb_reenter();
432 return (0);
433 }
434 #endif
435 mode = TRAP_USERMODE(tf) ? "user" : "kernel";
436
437 disable_interrupts(PSR_I|PSR_F);
438 if (td != NULL) {
439 printf("Fatal %s mode data abort: '%s'\n", mode,
440 data_aborts[fsr & FAULT_TYPE_MASK].desc);
441 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr);
442 if ((fsr & FAULT_IMPRECISE) == 0)
443 printf("%08x, ", far);
444 else
445 printf("Invalid, ");
446 printf("spsr=%08x\n", tf->tf_spsr);
447 } else {
448 printf("Fatal %s mode prefetch abort at 0x%08x\n",
449 mode, tf->tf_pc);
450 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr);
451 }
452
453 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n",
454 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3);
455 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n",
456 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7);
457 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n",
458 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11);
459 printf("r12=%08x, ", tf->tf_r12);
460
461 if (TRAP_USERMODE(tf))
462 printf("usp=%08x, ulr=%08x",
463 tf->tf_usr_sp, tf->tf_usr_lr);
464 else
465 printf("ssp=%08x, slr=%08x",
466 tf->tf_svc_sp, tf->tf_svc_lr);
467 printf(", pc =%08x\n\n", tf->tf_pc);
468
469 #ifdef KDB
470 if (debugger_on_panic) {
471 kdb_why = KDB_WHY_TRAP;
472 handled = kdb_trap(fsr, 0, tf);
473 kdb_why = KDB_WHY_UNSET;
474 if (handled)
475 return (0);
476 }
477 #endif
478 panic("Fatal abort");
479 /*NOTREACHED*/
480 }
481
482 /*
483 * dab_align() handles the following data aborts:
484 *
485 * FAULT_ALIGN_0 - Alignment fault
486 * FAULT_ALIGN_1 - Alignment fault
487 *
488 * These faults are fatal if they happen in kernel mode. Otherwise, we
489 * deliver a bus error to the process.
490 */
491 static int
dab_align(struct trapframe * tf,u_int fsr,u_int far,struct thread * td,struct ksig * ksig)492 dab_align(struct trapframe *tf, u_int fsr, u_int far, struct thread *td,
493 struct ksig *ksig)
494 {
495
496 /* Alignment faults are always fatal if they occur in kernel mode */
497 if (!TRAP_USERMODE(tf)) {
498 if (!td || !td->td_pcb->pcb_onfault)
499 dab_fatal(tf, fsr, far, td, ksig);
500 tf->tf_r0 = EFAULT;
501 tf->tf_pc = (int)td->td_pcb->pcb_onfault;
502 return (0);
503 }
504
505 /* pcb_onfault *must* be NULL at this point */
506
507 /* Deliver a bus error signal to the process */
508 ksig->code = 0;
509 ksig->signb = SIGBUS;
510 td->td_frame = tf;
511
512 return (1);
513 }
514
515 /*
516 * dab_buserr() handles the following data aborts:
517 *
518 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section
519 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page
520 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section
521 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page
522 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1
523 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2
524 *
525 * If pcb_onfault is set, flag the fault and return to the handler.
526 * If the fault occurred in user mode, give the process a SIGBUS.
527 *
528 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2
529 * can be flagged as imprecise in the FSR. This causes a real headache
530 * since some of the machine state is lost. In this case, tf->tf_pc
531 * may not actually point to the offending instruction. In fact, if
532 * we've taken a double abort fault, it generally points somewhere near
533 * the top of "data_abort_entry" in exception.S.
534 *
535 * In all other cases, these data aborts are considered fatal.
536 */
537 static int
dab_buserr(struct trapframe * tf,u_int fsr,u_int far,struct thread * td,struct ksig * ksig)538 dab_buserr(struct trapframe *tf, u_int fsr, u_int far, struct thread *td,
539 struct ksig *ksig)
540 {
541 struct pcb *pcb = td->td_pcb;
542
543 #ifdef __XSCALE__
544 if ((fsr & FAULT_IMPRECISE) != 0 &&
545 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) {
546 /*
547 * Oops, an imprecise, double abort fault. We've lost the
548 * r14_abt/spsr_abt values corresponding to the original
549 * abort, and the spsr saved in the trapframe indicates
550 * ABT mode.
551 */
552 tf->tf_spsr &= ~PSR_MODE;
553
554 /*
555 * We use a simple heuristic to determine if the double abort
556 * happened as a result of a kernel or user mode access.
557 * If the current trapframe is at the top of the kernel stack,
558 * the fault _must_ have come from user mode.
559 */
560 if (tf != ((struct trapframe *)pcb->pcb_regs.sf_sp) - 1) {
561 /*
562 * Kernel mode. We're either about to die a
563 * spectacular death, or pcb_onfault will come
564 * to our rescue. Either way, the current value
565 * of tf->tf_pc is irrelevant.
566 */
567 tf->tf_spsr |= PSR_SVC32_MODE;
568 if (pcb->pcb_onfault == NULL)
569 printf("\nKernel mode double abort!\n");
570 } else {
571 /*
572 * User mode. We've lost the program counter at the
573 * time of the fault (not that it was accurate anyway;
574 * it's not called an imprecise fault for nothing).
575 * About all we can do is copy r14_usr to tf_pc and
576 * hope for the best. The process is about to get a
577 * SIGBUS, so it's probably history anyway.
578 */
579 tf->tf_spsr |= PSR_USR32_MODE;
580 tf->tf_pc = tf->tf_usr_lr;
581 }
582 }
583
584 /* FAR is invalid for imprecise exceptions */
585 if ((fsr & FAULT_IMPRECISE) != 0)
586 far = 0;
587 #endif /* __XSCALE__ */
588
589 if (pcb->pcb_onfault) {
590 tf->tf_r0 = EFAULT;
591 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault;
592 return (0);
593 }
594
595 /*
596 * At this point, if the fault happened in kernel mode, we're toast
597 */
598 if (!TRAP_USERMODE(tf))
599 dab_fatal(tf, fsr, far, td, ksig);
600
601 /* Deliver a bus error signal to the process */
602 ksig->signb = SIGBUS;
603 ksig->code = 0;
604 td->td_frame = tf;
605
606 return (1);
607 }
608
609 /*
610 * void prefetch_abort_handler(struct trapframe *tf)
611 *
612 * Abort handler called when instruction execution occurs at
613 * a non existent or restricted (access permissions) memory page.
614 * If the address is invalid and we were in SVC mode then panic as
615 * the kernel should never prefetch abort.
616 * If the address is invalid and the page is mapped then the user process
617 * does no have read permission so send it a signal.
618 * Otherwise fault the page in and try again.
619 */
620 static void
prefetch_abort_handler(struct trapframe * tf)621 prefetch_abort_handler(struct trapframe *tf)
622 {
623 struct thread *td;
624 struct proc * p;
625 struct vm_map *map;
626 vm_offset_t fault_pc, va;
627 int error = 0;
628 struct ksig ksig;
629
630
631 #if 0
632 /* Update vmmeter statistics */
633 uvmexp.traps++;
634 #endif
635 #if 0
636 printf("prefetch abort handler: %p %p\n", (void*)tf->tf_pc,
637 (void*)tf->tf_usr_lr);
638 #endif
639
640 td = curthread;
641 p = td->td_proc;
642 PCPU_INC(cnt.v_trap);
643
644 if (TRAP_USERMODE(tf)) {
645 td->td_frame = tf;
646 if (td->td_ucred != td->td_proc->p_ucred)
647 cred_update_thread(td);
648 }
649 fault_pc = tf->tf_pc;
650 if (td->td_md.md_spinlock_count == 0) {
651 if (__predict_true(tf->tf_spsr & PSR_I) == 0)
652 enable_interrupts(PSR_I);
653 if (__predict_true(tf->tf_spsr & PSR_F) == 0)
654 enable_interrupts(PSR_F);
655 }
656
657 /* Prefetch aborts cannot happen in kernel mode */
658 if (__predict_false(!TRAP_USERMODE(tf)))
659 dab_fatal(tf, 0, tf->tf_pc, NULL, &ksig);
660 td->td_pticks = 0;
661
662
663 /* Ok validate the address, can only execute in USER space */
664 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS ||
665 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) {
666 ksig.signb = SIGSEGV;
667 ksig.code = 0;
668 goto do_trapsignal;
669 }
670
671 map = &td->td_proc->p_vmspace->vm_map;
672 va = trunc_page(fault_pc);
673
674 /*
675 * See if the pmap can handle this fault on its own...
676 */
677 #ifdef DEBUG
678 last_fault_code = -1;
679 #endif
680 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ, 1))
681 goto out;
682
683 if (map != kernel_map) {
684 PROC_LOCK(p);
685 p->p_lock++;
686 PROC_UNLOCK(p);
687 }
688
689 error = vm_fault(map, va, VM_PROT_READ | VM_PROT_EXECUTE,
690 VM_FAULT_NORMAL);
691 if (map != kernel_map) {
692 PROC_LOCK(p);
693 p->p_lock--;
694 PROC_UNLOCK(p);
695 }
696
697 if (__predict_true(error == 0))
698 goto out;
699
700 if (error == ENOMEM) {
701 printf("VM: pid %d (%s), uid %d killed: "
702 "out of swap\n", td->td_proc->p_pid, td->td_name,
703 (td->td_proc->p_ucred) ?
704 td->td_proc->p_ucred->cr_uid : -1);
705 ksig.signb = SIGKILL;
706 } else {
707 ksig.signb = SIGSEGV;
708 }
709 ksig.code = 0;
710
711 do_trapsignal:
712 call_trapsignal(td, ksig.signb, ksig.code);
713
714 out:
715 userret(td, tf);
716
717 }
718
719 extern int badaddr_read_1(const uint8_t *, uint8_t *);
720 extern int badaddr_read_2(const uint16_t *, uint16_t *);
721 extern int badaddr_read_4(const uint32_t *, uint32_t *);
722 /*
723 * Tentatively read an 8, 16, or 32-bit value from 'addr'.
724 * If the read succeeds, the value is written to 'rptr' and zero is returned.
725 * Else, return EFAULT.
726 */
727 int
badaddr_read(void * addr,size_t size,void * rptr)728 badaddr_read(void *addr, size_t size, void *rptr)
729 {
730 union {
731 uint8_t v1;
732 uint16_t v2;
733 uint32_t v4;
734 } u;
735 int rv;
736
737 cpu_drain_writebuf();
738
739 /* Read from the test address. */
740 switch (size) {
741 case sizeof(uint8_t):
742 rv = badaddr_read_1(addr, &u.v1);
743 if (rv == 0 && rptr)
744 *(uint8_t *) rptr = u.v1;
745 break;
746
747 case sizeof(uint16_t):
748 rv = badaddr_read_2(addr, &u.v2);
749 if (rv == 0 && rptr)
750 *(uint16_t *) rptr = u.v2;
751 break;
752
753 case sizeof(uint32_t):
754 rv = badaddr_read_4(addr, &u.v4);
755 if (rv == 0 && rptr)
756 *(uint32_t *) rptr = u.v4;
757 break;
758
759 default:
760 panic("badaddr: invalid size (%lu)", (u_long) size);
761 }
762
763 /* Return EFAULT if the address was invalid, else zero */
764 return (rv);
765 }
766