1 /* $NetBSD: fault.c,v 1.45 2003/11/20 14:44:36 scw Exp $ */
4 * Copyright 2004 Olivier Houchard
5 * Copyright 2003 Wasabi Systems, Inc.
8 * Written by Steve C. Woodford for Wasabi Systems, Inc.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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
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.
39 * Copyright (c) 1994-1997 Mark Brinicombe.
40 * Copyright (c) 1994 Brini.
41 * All rights reserved.
43 * This code is derived from software written for Brini by Mark Brinicombe
45 * Redistribution and use in source and binary forms, with or without
46 * modification, are permitted provided that the following conditions
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.
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
72 * RiscBSD kernel project
82 #include <sys/dtrace_bsd.h>
85 #include <sys/cdefs.h>
86 __FBSDID("$FreeBSD$");
88 #include <sys/param.h>
89 #include <sys/systm.h>
92 #include <sys/mutex.h>
93 #include <sys/signalvar.h>
97 #include <vm/vm_kern.h>
98 #include <vm/vm_map.h>
99 #include <vm/vm_extern.h>
101 #include <machine/cpu.h>
102 #include <machine/frame.h>
103 #include <machine/machdep.h>
104 #include <machine/pcb.h>
105 #include <machine/vmparam.h>
111 extern char fusubailout[];
114 int last_fault_code; /* For the benefit of pmap_fault_fixup() */
122 int (*func)(struct trapframe *, u_int, u_int, struct thread *,
127 static int dab_fatal(struct trapframe *, u_int, u_int, struct thread *,
129 static int dab_align(struct trapframe *, u_int, u_int, struct thread *,
131 static int dab_buserr(struct trapframe *, u_int, u_int, struct thread *,
133 static void prefetch_abort_handler(struct trapframe *);
135 static const struct data_abort data_aborts[] = {
136 {dab_fatal, "Vector Exception"},
137 {dab_align, "Alignment Fault 1"},
138 {dab_fatal, "Terminal Exception"},
139 {dab_align, "Alignment Fault 3"},
140 {dab_buserr, "External Linefetch Abort (S)"},
141 {NULL, "Translation Fault (S)"},
142 #if (ARM_MMU_V6 + ARM_MMU_V7) != 0
143 {NULL, "Translation Flag Fault"},
145 {dab_buserr, "External Linefetch Abort (P)"},
147 {NULL, "Translation Fault (P)"},
148 {dab_buserr, "External Non-Linefetch Abort (S)"},
149 {NULL, "Domain Fault (S)"},
150 {dab_buserr, "External Non-Linefetch Abort (P)"},
151 {NULL, "Domain Fault (P)"},
152 {dab_buserr, "External Translation Abort (L1)"},
153 {NULL, "Permission Fault (S)"},
154 {dab_buserr, "External Translation Abort (L2)"},
155 {NULL, "Permission Fault (P)"}
158 /* Determine if a fault came from user mode */
159 #define TRAP_USERMODE(tf) ((tf->tf_spsr & PSR_MODE) == PSR_USR32_MODE)
161 /* Determine if 'x' is a permission fault */
162 #define IS_PERMISSION_FAULT(x) \
163 (((1 << ((x) & FAULT_TYPE_MASK)) & \
164 ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0)
167 call_trapsignal(struct thread *td, int sig, u_long code)
171 ksiginfo_init_trap(&ksi);
173 ksi.ksi_code = (int)code;
174 trapsignal(td, &ksi);
178 abort_handler(struct trapframe *tf, int type)
183 u_int user, far, fsr;
192 return (prefetch_abort_handler(tf));
194 /* Grab FAR/FSR before enabling interrupts */
195 far = cpu_faultaddress();
196 fsr = cpu_faultstatus();
198 printf("data abort: fault address=%p (from pc=%p lr=%p)\n",
199 (void*)far, (void*)tf->tf_pc, (void*)tf->tf_svc_lr);
202 /* Update vmmeter statistics */
210 PCPU_INC(cnt.v_trap);
211 /* Data abort came from user mode? */
212 user = TRAP_USERMODE(tf);
217 if (td->td_ucred != td->td_proc->p_ucred)
218 cred_update_thread(td);
221 /* Grab the current pcb */
223 /* Re-enable interrupts if they were enabled previously */
224 if (td->td_md.md_spinlock_count == 0) {
225 if (__predict_true(tf->tf_spsr & PSR_I) == 0)
226 enable_interrupts(PSR_I);
227 if (__predict_true(tf->tf_spsr & PSR_F) == 0)
228 enable_interrupts(PSR_F);
232 /* Invoke the appropriate handler, if necessary */
233 if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) {
234 if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far,
242 * At this point, we're dealing with one of the following data aborts:
244 * FAULT_TRANS_S - Translation -- Section
245 * FAULT_TRANS_P - Translation -- Page
246 * FAULT_DOMAIN_S - Domain -- Section
247 * FAULT_DOMAIN_P - Domain -- Page
248 * FAULT_PERM_S - Permission -- Section
249 * FAULT_PERM_P - Permission -- Page
251 * These are the main virtual memory-related faults signalled by
255 /* fusubailout is used by [fs]uswintr to avoid page faulting */
256 if (__predict_false(pcb->pcb_onfault == fusubailout)) {
258 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault;
263 * Make sure the Program Counter is sane. We could fall foul of
264 * someone executing Thumb code, in which case the PC might not
265 * be word-aligned. This would cause a kernel alignment fault
266 * further down if we have to decode the current instruction.
267 * XXX: It would be nice to be able to support Thumb at some point.
269 if (__predict_false((tf->tf_pc & 3) != 0)) {
272 * Give the user an illegal instruction signal.
274 /* Deliver a SIGILL to the process */
281 * The kernel never executes Thumb code.
283 printf("\ndata_abort_fault: Misaligned Kernel-mode "
284 "Program Counter\n");
285 dab_fatal(tf, fsr, far, td, &ksig);
288 va = trunc_page((vm_offset_t)far);
291 * It is only a kernel address space fault iff:
293 * 2. pcb_onfault not set or
294 * 3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction.
296 if (user == 0 && (va >= VM_MIN_KERNEL_ADDRESS ||
297 (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) &&
298 __predict_true((pcb->pcb_onfault == NULL ||
299 (ReadWord(tf->tf_pc) & 0x05200000) != 0x04200000))) {
302 /* Was the fault due to the FPE/IPKDB ? */
303 if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) {
306 * Force exit via userret()
307 * This is necessary as the FPE is an extension to
308 * userland that actually runs in a priveledged mode
309 * but uses USR mode permissions for its accesses.
312 ksig.signb = SIGSEGV;
317 map = &td->td_proc->p_vmspace->vm_map;
321 * We need to know whether the page should be mapped as R or R/W. On
322 * armv6 and later the fault status register indicates whether the
323 * access was a read or write. Prior to armv6, we know that a
324 * permission fault can only be the result of a write to a read-only
325 * location, so we can deal with those quickly. Otherwise we need to
326 * disassemble the faulting instruction to determine if it was a write.
328 #if ARM_ARCH_6 || ARM_ARCH_7A
329 ftype = (fsr & FAULT_WNR) ? VM_PROT_READ | VM_PROT_WRITE : VM_PROT_READ;
331 if (IS_PERMISSION_FAULT(fsr))
332 ftype = VM_PROT_WRITE;
334 u_int insn = ReadWord(tf->tf_pc);
336 if (((insn & 0x0c100000) == 0x04000000) || /* STR/STRB */
337 ((insn & 0x0e1000b0) == 0x000000b0) || /* STRH/STRD */
338 ((insn & 0x0a100000) == 0x08000000)) { /* STM/CDT */
339 ftype = VM_PROT_WRITE;
341 if ((insn & 0x0fb00ff0) == 0x01000090) /* SWP */
342 ftype = VM_PROT_READ | VM_PROT_WRITE;
344 ftype = VM_PROT_READ;
350 * See if the fault is as a result of ref/mod emulation,
351 * or domain mismatch.
354 last_fault_code = fsr;
356 if (td->td_critnest != 0 || WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK,
357 NULL, "Kernel page fault") != 0)
358 goto fatal_pagefault;
360 if (pmap_fault_fixup(vmspace_pmap(td->td_proc->p_vmspace), va, ftype,
365 onfault = pcb->pcb_onfault;
366 pcb->pcb_onfault = NULL;
367 if (map != kernel_map) {
372 error = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
373 pcb->pcb_onfault = onfault;
375 if (map != kernel_map) {
380 if (__predict_true(error == 0))
384 if (pcb->pcb_onfault) {
386 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault;
390 printf("\nvm_fault(%p, %x, %x, 0) -> %x\n", map, va, ftype,
392 dab_fatal(tf, fsr, far, td, &ksig);
396 if (error == ENOMEM) {
397 printf("VM: pid %d (%s), uid %d killed: "
398 "out of swap\n", td->td_proc->p_pid, td->td_name,
399 (td->td_proc->p_ucred) ?
400 td->td_proc->p_ucred->cr_uid : -1);
401 ksig.signb = SIGKILL;
403 ksig.signb = SIGSEGV;
407 call_trapsignal(td, ksig.signb, ksig.code);
409 /* If returning to user mode, make sure to invoke userret() */
415 * dab_fatal() handles the following data aborts:
417 * FAULT_WRTBUF_0 - Vector Exception
418 * FAULT_WRTBUF_1 - Terminal Exception
420 * We should never see these on a properly functioning system.
422 * This function is also called by the other handlers if they
423 * detect a fatal problem.
425 * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort.
428 dab_fatal(struct trapframe *tf, u_int fsr, u_int far, struct thread *td,
434 if (!TRAP_USERMODE(tf)) {
435 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(tf, far & FAULT_TYPE_MASK))
440 mode = TRAP_USERMODE(tf) ? "user" : "kernel";
442 disable_interrupts(PSR_I|PSR_F);
444 printf("Fatal %s mode data abort: '%s'\n", mode,
445 data_aborts[fsr & FAULT_TYPE_MASK].desc);
446 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr);
447 if ((fsr & FAULT_IMPRECISE) == 0)
448 printf("%08x, ", far);
451 printf("spsr=%08x\n", tf->tf_spsr);
453 printf("Fatal %s mode prefetch abort at 0x%08x\n",
455 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr);
458 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n",
459 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3);
460 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n",
461 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7);
462 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n",
463 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11);
464 printf("r12=%08x, ", tf->tf_r12);
466 if (TRAP_USERMODE(tf))
467 printf("usp=%08x, ulr=%08x",
468 tf->tf_usr_sp, tf->tf_usr_lr);
470 printf("ssp=%08x, slr=%08x",
471 tf->tf_svc_sp, tf->tf_svc_lr);
472 printf(", pc =%08x\n\n", tf->tf_pc);
475 if (debugger_on_panic || kdb_active)
476 if (kdb_trap(fsr, 0, tf))
479 panic("Fatal abort");
484 * dab_align() handles the following data aborts:
486 * FAULT_ALIGN_0 - Alignment fault
487 * FAULT_ALIGN_1 - Alignment fault
489 * These faults are fatal if they happen in kernel mode. Otherwise, we
490 * deliver a bus error to the process.
493 dab_align(struct trapframe *tf, u_int fsr, u_int far, struct thread *td,
497 /* Alignment faults are always fatal if they occur in kernel mode */
498 if (!TRAP_USERMODE(tf)) {
499 if (!td || !td->td_pcb->pcb_onfault)
500 dab_fatal(tf, fsr, far, td, ksig);
502 tf->tf_pc = (int)td->td_pcb->pcb_onfault;
506 /* pcb_onfault *must* be NULL at this point */
508 /* Deliver a bus error signal to the process */
510 ksig->signb = SIGBUS;
517 * dab_buserr() handles the following data aborts:
519 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section
520 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page
521 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section
522 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page
523 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1
524 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2
526 * If pcb_onfault is set, flag the fault and return to the handler.
527 * If the fault occurred in user mode, give the process a SIGBUS.
529 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2
530 * can be flagged as imprecise in the FSR. This causes a real headache
531 * since some of the machine state is lost. In this case, tf->tf_pc
532 * may not actually point to the offending instruction. In fact, if
533 * we've taken a double abort fault, it generally points somewhere near
534 * the top of "data_abort_entry" in exception.S.
536 * In all other cases, these data aborts are considered fatal.
539 dab_buserr(struct trapframe *tf, u_int fsr, u_int far, struct thread *td,
542 struct pcb *pcb = td->td_pcb;
545 if ((fsr & FAULT_IMPRECISE) != 0 &&
546 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) {
548 * Oops, an imprecise, double abort fault. We've lost the
549 * r14_abt/spsr_abt values corresponding to the original
550 * abort, and the spsr saved in the trapframe indicates
553 tf->tf_spsr &= ~PSR_MODE;
556 * We use a simple heuristic to determine if the double abort
557 * happened as a result of a kernel or user mode access.
558 * If the current trapframe is at the top of the kernel stack,
559 * the fault _must_ have come from user mode.
561 if (tf != ((struct trapframe *)pcb->pcb_regs.sf_sp) - 1) {
563 * Kernel mode. We're either about to die a
564 * spectacular death, or pcb_onfault will come
565 * to our rescue. Either way, the current value
566 * of tf->tf_pc is irrelevant.
568 tf->tf_spsr |= PSR_SVC32_MODE;
569 if (pcb->pcb_onfault == NULL)
570 printf("\nKernel mode double abort!\n");
573 * User mode. We've lost the program counter at the
574 * time of the fault (not that it was accurate anyway;
575 * it's not called an imprecise fault for nothing).
576 * About all we can do is copy r14_usr to tf_pc and
577 * hope for the best. The process is about to get a
578 * SIGBUS, so it's probably history anyway.
580 tf->tf_spsr |= PSR_USR32_MODE;
581 tf->tf_pc = tf->tf_usr_lr;
585 /* FAR is invalid for imprecise exceptions */
586 if ((fsr & FAULT_IMPRECISE) != 0)
588 #endif /* __XSCALE__ */
590 if (pcb->pcb_onfault) {
592 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault;
597 * At this point, if the fault happened in kernel mode, we're toast
599 if (!TRAP_USERMODE(tf))
600 dab_fatal(tf, fsr, far, td, ksig);
602 /* Deliver a bus error signal to the process */
603 ksig->signb = SIGBUS;
611 * void prefetch_abort_handler(struct trapframe *tf)
613 * Abort handler called when instruction execution occurs at
614 * a non existent or restricted (access permissions) memory page.
615 * If the address is invalid and we were in SVC mode then panic as
616 * the kernel should never prefetch abort.
617 * If the address is invalid and the page is mapped then the user process
618 * does no have read permission so send it a signal.
619 * Otherwise fault the page in and try again.
622 prefetch_abort_handler(struct trapframe *tf)
627 vm_offset_t fault_pc, va;
633 /* Update vmmeter statistics */
637 printf("prefetch abort handler: %p %p\n", (void*)tf->tf_pc,
638 (void*)tf->tf_usr_lr);
643 PCPU_INC(cnt.v_trap);
645 if (TRAP_USERMODE(tf)) {
647 if (td->td_ucred != td->td_proc->p_ucred)
648 cred_update_thread(td);
650 fault_pc = tf->tf_pc;
651 if (td->td_md.md_spinlock_count == 0) {
652 if (__predict_true(tf->tf_spsr & PSR_I) == 0)
653 enable_interrupts(PSR_I);
654 if (__predict_true(tf->tf_spsr & PSR_F) == 0)
655 enable_interrupts(PSR_F);
658 /* Prefetch aborts cannot happen in kernel mode */
659 if (__predict_false(!TRAP_USERMODE(tf)))
660 dab_fatal(tf, 0, tf->tf_pc, NULL, &ksig);
664 /* Ok validate the address, can only execute in USER space */
665 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS ||
666 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) {
667 ksig.signb = SIGSEGV;
672 map = &td->td_proc->p_vmspace->vm_map;
673 va = trunc_page(fault_pc);
676 * See if the pmap can handle this fault on its own...
679 last_fault_code = -1;
681 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ, 1))
684 if (map != kernel_map) {
690 error = vm_fault(map, va, VM_PROT_READ | VM_PROT_EXECUTE,
692 if (map != kernel_map) {
698 if (__predict_true(error == 0))
701 if (error == ENOMEM) {
702 printf("VM: pid %d (%s), uid %d killed: "
703 "out of swap\n", td->td_proc->p_pid, td->td_name,
704 (td->td_proc->p_ucred) ?
705 td->td_proc->p_ucred->cr_uid : -1);
706 ksig.signb = SIGKILL;
708 ksig.signb = SIGSEGV;
713 call_trapsignal(td, ksig.signb, ksig.code);
720 extern int badaddr_read_1(const uint8_t *, uint8_t *);
721 extern int badaddr_read_2(const uint16_t *, uint16_t *);
722 extern int badaddr_read_4(const uint32_t *, uint32_t *);
724 * Tentatively read an 8, 16, or 32-bit value from 'addr'.
725 * If the read succeeds, the value is written to 'rptr' and zero is returned.
726 * Else, return EFAULT.
729 badaddr_read(void *addr, size_t size, void *rptr)
738 cpu_drain_writebuf();
740 /* Read from the test address. */
742 case sizeof(uint8_t):
743 rv = badaddr_read_1(addr, &u.v1);
745 *(uint8_t *) rptr = u.v1;
748 case sizeof(uint16_t):
749 rv = badaddr_read_2(addr, &u.v2);
751 *(uint16_t *) rptr = u.v2;
754 case sizeof(uint32_t):
755 rv = badaddr_read_4(addr, &u.v4);
757 *(uint32_t *) rptr = u.v4;
761 panic("badaddr: invalid size (%lu)", (u_long) size);
764 /* Return EFAULT if the address was invalid, else zero */