The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/arm/arm/trap.c

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    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: releng/10.2/sys/arm/arm/trap.c 278656 2015-02-13 02:02:12Z ian $");
   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/cpu.h>
   99 #include <machine/frame.h>
  100 #include <machine/machdep.h>
  101 #include <machine/pcb.h>
  102 #include <machine/vmparam.h>
  103 
  104 #ifdef KDB
  105 #include <sys/kdb.h>
  106 #endif
  107 
  108 extern char fusubailout[];
  109 
  110 #ifdef DEBUG
  111 int last_fault_code;    /* For the benefit of pmap_fault_fixup() */
  112 #endif
  113 
  114 struct ksig {
  115         int signb;
  116         u_long code;
  117 };
  118 struct data_abort {
  119         int (*func)(struct trapframe *, u_int, u_int, struct thread *, 
  120             struct ksig *);
  121         const char *desc;
  122 };
  123 
  124 static int dab_fatal(struct trapframe *, u_int, u_int, struct thread *,
  125     struct ksig *);
  126 static int dab_align(struct trapframe *, u_int, u_int, struct thread *,
  127     struct ksig *);
  128 static int dab_buserr(struct trapframe *, u_int, u_int, struct thread *,
  129     struct ksig *);
  130 static void prefetch_abort_handler(struct trapframe *);
  131 
  132 static const struct data_abort data_aborts[] = {
  133         {dab_fatal,     "Vector Exception"},
  134         {dab_align,     "Alignment Fault 1"},
  135         {dab_fatal,     "Terminal Exception"},
  136         {dab_align,     "Alignment Fault 3"},
  137         {dab_buserr,    "External Linefetch Abort (S)"},
  138         {NULL,          "Translation Fault (S)"},
  139 #if (ARM_MMU_V6 + ARM_MMU_V7) != 0
  140         {NULL,          "Translation Flag Fault"},
  141 #else
  142         {dab_buserr,    "External Linefetch Abort (P)"},
  143 #endif
  144         {NULL,          "Translation Fault (P)"},
  145         {dab_buserr,    "External Non-Linefetch Abort (S)"},
  146         {NULL,          "Domain Fault (S)"},
  147         {dab_buserr,    "External Non-Linefetch Abort (P)"},
  148         {NULL,          "Domain Fault (P)"},
  149         {dab_buserr,    "External Translation Abort (L1)"},
  150         {NULL,          "Permission Fault (S)"},
  151         {dab_buserr,    "External Translation Abort (L2)"},
  152         {NULL,          "Permission Fault (P)"}
  153 };
  154 
  155 /* Determine if a fault came from user mode */
  156 #define TRAP_USERMODE(tf)       ((tf->tf_spsr & PSR_MODE) == PSR_USR32_MODE)
  157 
  158 /* Determine if 'x' is a permission fault */
  159 #define IS_PERMISSION_FAULT(x)                                  \
  160         (((1 << ((x) & FAULT_TYPE_MASK)) &                      \
  161           ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0)
  162 
  163 static __inline void
  164 call_trapsignal(struct thread *td, int sig, u_long code)
  165 {
  166         ksiginfo_t ksi;
  167 
  168         ksiginfo_init_trap(&ksi);
  169         ksi.ksi_signo = sig;
  170         ksi.ksi_code = (int)code;
  171         trapsignal(td, &ksi);
  172 }
  173 
  174 void
  175 abort_handler(struct trapframe *tf, int type)
  176 {
  177         struct vm_map *map;
  178         struct pcb *pcb;
  179         struct thread *td;
  180         u_int user, far, fsr;
  181         vm_prot_t ftype;
  182         void *onfault;
  183         vm_offset_t va;
  184         int error = 0;
  185         struct ksig ksig;
  186         struct proc *p;
  187 
  188         if (type == 1)
  189                 return (prefetch_abort_handler(tf));
  190 
  191         /* Grab FAR/FSR before enabling interrupts */
  192         far = cpu_faultaddress();
  193         fsr = cpu_faultstatus();
  194 #if 0
  195         printf("data abort: fault address=%p (from pc=%p lr=%p)\n",
  196                (void*)far, (void*)tf->tf_pc, (void*)tf->tf_svc_lr);
  197 #endif
  198 
  199         /* Update vmmeter statistics */
  200 #if 0
  201         vmexp.traps++;
  202 #endif
  203 
  204         td = curthread;
  205         p = td->td_proc;
  206 
  207         PCPU_INC(cnt.v_trap);
  208         /* Data abort came from user mode? */
  209         user = TRAP_USERMODE(tf);
  210 
  211         if (user) {
  212                 td->td_pticks = 0;
  213                 td->td_frame = tf;
  214                 if (td->td_ucred != td->td_proc->p_ucred)
  215                         cred_update_thread(td);
  216 
  217         }
  218         /* Grab the current pcb */
  219         pcb = td->td_pcb;
  220         /* Re-enable interrupts if they were enabled previously */
  221         if (td->td_md.md_spinlock_count == 0) {
  222                 if (__predict_true(tf->tf_spsr & PSR_I) == 0)
  223                         enable_interrupts(PSR_I);
  224                 if (__predict_true(tf->tf_spsr & PSR_F) == 0)
  225                         enable_interrupts(PSR_F);
  226         }
  227 
  228 
  229         /* Invoke the appropriate handler, if necessary */
  230         if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) {
  231                 if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far,
  232                     td, &ksig)) {
  233                         goto do_trapsignal;
  234                 }
  235                 goto out;
  236         }
  237 
  238         /*
  239          * At this point, we're dealing with one of the following data aborts:
  240          *
  241          *  FAULT_TRANS_S  - Translation -- Section
  242          *  FAULT_TRANS_P  - Translation -- Page
  243          *  FAULT_DOMAIN_S - Domain -- Section
  244          *  FAULT_DOMAIN_P - Domain -- Page
  245          *  FAULT_PERM_S   - Permission -- Section
  246          *  FAULT_PERM_P   - Permission -- Page
  247          *
  248          * These are the main virtual memory-related faults signalled by
  249          * the MMU.
  250          */
  251 
  252         /* fusubailout is used by [fs]uswintr to avoid page faulting */
  253         if (__predict_false(pcb->pcb_onfault == fusubailout)) {
  254                 tf->tf_r0 = EFAULT;
  255                 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault;
  256                 return;
  257         }
  258 
  259         /*
  260          * Make sure the Program Counter is sane. We could fall foul of
  261          * someone executing Thumb code, in which case the PC might not
  262          * be word-aligned. This would cause a kernel alignment fault
  263          * further down if we have to decode the current instruction.
  264          * XXX: It would be nice to be able to support Thumb at some point.
  265          */
  266         if (__predict_false((tf->tf_pc & 3) != 0)) {
  267                 if (user) {
  268                         /*
  269                          * Give the user an illegal instruction signal.
  270                          */
  271                         /* Deliver a SIGILL to the process */
  272                         ksig.signb = SIGILL;
  273                         ksig.code = 0;
  274                         goto do_trapsignal;
  275                 }
  276 
  277                 /*
  278                  * The kernel never executes Thumb code.
  279                  */
  280                 printf("\ndata_abort_fault: Misaligned Kernel-mode "
  281                     "Program Counter\n");
  282                 dab_fatal(tf, fsr, far, td, &ksig);
  283         }
  284 
  285         va = trunc_page((vm_offset_t)far);
  286 
  287         /*
  288          * It is only a kernel address space fault iff:
  289          *      1. user == 0  and
  290          *      2. pcb_onfault not set or
  291          *      3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction.
  292          */
  293         if (user == 0 && (va >= VM_MIN_KERNEL_ADDRESS ||
  294             (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) &&
  295             __predict_true((pcb->pcb_onfault == NULL ||
  296              (ReadWord(tf->tf_pc) & 0x05200000) != 0x04200000))) {
  297                 map = kernel_map;
  298 
  299                 /* Was the fault due to the FPE/IPKDB ? */
  300                 if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) {
  301 
  302                         /*
  303                          * Force exit via userret()
  304                          * This is necessary as the FPE is an extension to
  305                          * userland that actually runs in a priveledged mode
  306                          * but uses USR mode permissions for its accesses.
  307                          */
  308                         user = 1;
  309                         ksig.signb = SIGSEGV;
  310                         ksig.code = 0;
  311                         goto do_trapsignal;
  312                 }
  313         } else {
  314                 map = &td->td_proc->p_vmspace->vm_map;
  315         }
  316 
  317         /*
  318          * We need to know whether the page should be mapped as R or R/W.  On
  319          * armv6 and later the fault status register indicates whether the
  320          * access was a read or write.  Prior to armv6, we know that a
  321          * permission fault can only be the result of a write to a read-only
  322          * location, so we can deal with those quickly.  Otherwise we need to
  323          * disassemble the faulting instruction to determine if it was a write.
  324          */
  325 #if ARM_ARCH_6 || ARM_ARCH_7A
  326         ftype = (fsr & FAULT_WNR) ? VM_PROT_READ | VM_PROT_WRITE : VM_PROT_READ;
  327 #else
  328         if (IS_PERMISSION_FAULT(fsr))
  329                 ftype = VM_PROT_WRITE;
  330         else {
  331                 u_int insn = ReadWord(tf->tf_pc);
  332 
  333                 if (((insn & 0x0c100000) == 0x04000000) ||      /* STR/STRB */
  334                     ((insn & 0x0e1000b0) == 0x000000b0) ||      /* STRH/STRD */
  335                     ((insn & 0x0a100000) == 0x08000000)) {      /* STM/CDT */
  336                         ftype = VM_PROT_WRITE;
  337                 } else {
  338                         if ((insn & 0x0fb00ff0) == 0x01000090)  /* SWP */
  339                                 ftype = VM_PROT_READ | VM_PROT_WRITE;
  340                         else
  341                                 ftype = VM_PROT_READ;
  342                 }
  343         }
  344 #endif
  345 
  346         /*
  347          * See if the fault is as a result of ref/mod emulation,
  348          * or domain mismatch.
  349          */
  350 #ifdef DEBUG
  351         last_fault_code = fsr;
  352 #endif
  353         if (pmap_fault_fixup(vmspace_pmap(td->td_proc->p_vmspace), va, ftype,
  354             user)) {
  355                 goto out;
  356         }
  357 
  358         onfault = pcb->pcb_onfault;
  359         pcb->pcb_onfault = NULL;
  360         if (map != kernel_map) {
  361                 PROC_LOCK(p);
  362                 p->p_lock++;
  363                 PROC_UNLOCK(p);
  364         }
  365         error = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
  366         pcb->pcb_onfault = onfault;
  367 
  368         if (map != kernel_map) {
  369                 PROC_LOCK(p);
  370                 p->p_lock--;
  371                 PROC_UNLOCK(p);
  372         }
  373         if (__predict_true(error == 0))
  374                 goto out;
  375         if (user == 0) {
  376                 if (pcb->pcb_onfault) {
  377                         tf->tf_r0 = error;
  378                         tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault;
  379                         return;
  380                 }
  381 
  382                 printf("\nvm_fault(%p, %x, %x, 0) -> %x\n", map, va, ftype,
  383                     error);
  384                 dab_fatal(tf, fsr, far, td, &ksig);
  385         }
  386 
  387 
  388         if (error == ENOMEM) {
  389                 printf("VM: pid %d (%s), uid %d killed: "
  390                     "out of swap\n", td->td_proc->p_pid, td->td_name,
  391                     (td->td_proc->p_ucred) ?
  392                      td->td_proc->p_ucred->cr_uid : -1);
  393                 ksig.signb = SIGKILL;
  394         } else {
  395                 ksig.signb = SIGSEGV;
  396         }
  397         ksig.code = 0;
  398 do_trapsignal:
  399         call_trapsignal(td, ksig.signb, ksig.code);
  400 out:
  401         /* If returning to user mode, make sure to invoke userret() */
  402         if (user)
  403                 userret(td, tf);
  404 }
  405 
  406 /*
  407  * dab_fatal() handles the following data aborts:
  408  *
  409  *  FAULT_WRTBUF_0 - Vector Exception
  410  *  FAULT_WRTBUF_1 - Terminal Exception
  411  *
  412  * We should never see these on a properly functioning system.
  413  *
  414  * This function is also called by the other handlers if they
  415  * detect a fatal problem.
  416  *
  417  * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort.
  418  */
  419 static int
  420 dab_fatal(struct trapframe *tf, u_int fsr, u_int far, struct thread *td,
  421     struct ksig *ksig)
  422 {
  423         const char *mode;
  424 
  425         mode = TRAP_USERMODE(tf) ? "user" : "kernel";
  426 
  427         disable_interrupts(PSR_I|PSR_F);
  428         if (td != NULL) {
  429                 printf("Fatal %s mode data abort: '%s'\n", mode,
  430                     data_aborts[fsr & FAULT_TYPE_MASK].desc);
  431                 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr);
  432                 if ((fsr & FAULT_IMPRECISE) == 0)
  433                         printf("%08x, ", far);
  434                 else
  435                         printf("Invalid,  ");
  436                 printf("spsr=%08x\n", tf->tf_spsr);
  437         } else {
  438                 printf("Fatal %s mode prefetch abort at 0x%08x\n",
  439                     mode, tf->tf_pc);
  440                 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr);
  441         }
  442 
  443         printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n",
  444             tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3);
  445         printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n",
  446             tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7);
  447         printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n",
  448             tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11);
  449         printf("r12=%08x, ", tf->tf_r12);
  450 
  451         if (TRAP_USERMODE(tf))
  452                 printf("usp=%08x, ulr=%08x",
  453                     tf->tf_usr_sp, tf->tf_usr_lr);
  454         else
  455                 printf("ssp=%08x, slr=%08x",
  456                     tf->tf_svc_sp, tf->tf_svc_lr);
  457         printf(", pc =%08x\n\n", tf->tf_pc);
  458 
  459 #ifdef KDB
  460         if (debugger_on_panic || kdb_active)
  461                 if (kdb_trap(fsr, 0, tf))
  462                         return (0);
  463 #endif
  464         panic("Fatal abort");
  465         /*NOTREACHED*/
  466 }
  467 
  468 /*
  469  * dab_align() handles the following data aborts:
  470  *
  471  *  FAULT_ALIGN_0 - Alignment fault
  472  *  FAULT_ALIGN_1 - Alignment fault
  473  *
  474  * These faults are fatal if they happen in kernel mode. Otherwise, we
  475  * deliver a bus error to the process.
  476  */
  477 static int
  478 dab_align(struct trapframe *tf, u_int fsr, u_int far, struct thread *td,
  479     struct ksig *ksig)
  480 {
  481 
  482         /* Alignment faults are always fatal if they occur in kernel mode */
  483         if (!TRAP_USERMODE(tf)) {
  484                 if (!td || !td->td_pcb->pcb_onfault)
  485                         dab_fatal(tf, fsr, far, td, ksig);
  486                 tf->tf_r0 = EFAULT;
  487                 tf->tf_pc = (int)td->td_pcb->pcb_onfault;
  488                 return (0);
  489         }
  490 
  491         /* pcb_onfault *must* be NULL at this point */
  492 
  493         /* Deliver a bus error signal to the process */
  494         ksig->code = 0;
  495         ksig->signb = SIGBUS;
  496         td->td_frame = tf;
  497 
  498         return (1);
  499 }
  500 
  501 /*
  502  * dab_buserr() handles the following data aborts:
  503  *
  504  *  FAULT_BUSERR_0 - External Abort on Linefetch -- Section
  505  *  FAULT_BUSERR_1 - External Abort on Linefetch -- Page
  506  *  FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section
  507  *  FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page
  508  *  FAULT_BUSTRNL1 - External abort on Translation -- Level 1
  509  *  FAULT_BUSTRNL2 - External abort on Translation -- Level 2
  510  *
  511  * If pcb_onfault is set, flag the fault and return to the handler.
  512  * If the fault occurred in user mode, give the process a SIGBUS.
  513  *
  514  * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2
  515  * can be flagged as imprecise in the FSR. This causes a real headache
  516  * since some of the machine state is lost. In this case, tf->tf_pc
  517  * may not actually point to the offending instruction. In fact, if
  518  * we've taken a double abort fault, it generally points somewhere near
  519  * the top of "data_abort_entry" in exception.S.
  520  *
  521  * In all other cases, these data aborts are considered fatal.
  522  */
  523 static int
  524 dab_buserr(struct trapframe *tf, u_int fsr, u_int far, struct thread *td,
  525     struct ksig *ksig)
  526 {
  527         struct pcb *pcb = td->td_pcb;
  528 
  529 #ifdef __XSCALE__
  530         if ((fsr & FAULT_IMPRECISE) != 0 &&
  531             (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) {
  532                 /*
  533                  * Oops, an imprecise, double abort fault. We've lost the
  534                  * r14_abt/spsr_abt values corresponding to the original
  535                  * abort, and the spsr saved in the trapframe indicates
  536                  * ABT mode.
  537                  */
  538                 tf->tf_spsr &= ~PSR_MODE;
  539 
  540                 /*
  541                  * We use a simple heuristic to determine if the double abort
  542                  * happened as a result of a kernel or user mode access.
  543                  * If the current trapframe is at the top of the kernel stack,
  544                  * the fault _must_ have come from user mode.
  545                  */
  546                 if (tf != ((struct trapframe *)pcb->pcb_regs.sf_sp) - 1) {
  547                         /*
  548                          * Kernel mode. We're either about to die a
  549                          * spectacular death, or pcb_onfault will come
  550                          * to our rescue. Either way, the current value
  551                          * of tf->tf_pc is irrelevant.
  552                          */
  553                         tf->tf_spsr |= PSR_SVC32_MODE;
  554                         if (pcb->pcb_onfault == NULL)
  555                                 printf("\nKernel mode double abort!\n");
  556                 } else {
  557                         /*
  558                          * User mode. We've lost the program counter at the
  559                          * time of the fault (not that it was accurate anyway;
  560                          * it's not called an imprecise fault for nothing).
  561                          * About all we can do is copy r14_usr to tf_pc and
  562                          * hope for the best. The process is about to get a
  563                          * SIGBUS, so it's probably history anyway.
  564                          */
  565                         tf->tf_spsr |= PSR_USR32_MODE;
  566                         tf->tf_pc = tf->tf_usr_lr;
  567                 }
  568         }
  569 
  570         /* FAR is invalid for imprecise exceptions */
  571         if ((fsr & FAULT_IMPRECISE) != 0)
  572                 far = 0;
  573 #endif /* __XSCALE__ */
  574 
  575         if (pcb->pcb_onfault) {
  576                 tf->tf_r0 = EFAULT;
  577                 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault;
  578                 return (0);
  579         }
  580 
  581         /*
  582          * At this point, if the fault happened in kernel mode, we're toast
  583          */
  584         if (!TRAP_USERMODE(tf))
  585                 dab_fatal(tf, fsr, far, td, ksig);
  586 
  587         /* Deliver a bus error signal to the process */
  588         ksig->signb = SIGBUS;
  589         ksig->code = 0;
  590         td->td_frame = tf;
  591 
  592         return (1);
  593 }
  594 
  595 /*
  596  * void prefetch_abort_handler(struct trapframe *tf)
  597  *
  598  * Abort handler called when instruction execution occurs at
  599  * a non existent or restricted (access permissions) memory page.
  600  * If the address is invalid and we were in SVC mode then panic as
  601  * the kernel should never prefetch abort.
  602  * If the address is invalid and the page is mapped then the user process
  603  * does no have read permission so send it a signal.
  604  * Otherwise fault the page in and try again.
  605  */
  606 static void
  607 prefetch_abort_handler(struct trapframe *tf)
  608 {
  609         struct thread *td;
  610         struct proc * p;
  611         struct vm_map *map;
  612         vm_offset_t fault_pc, va;
  613         int error = 0;
  614         struct ksig ksig;
  615 
  616 
  617 #if 0
  618         /* Update vmmeter statistics */
  619         uvmexp.traps++;
  620 #endif
  621 #if 0
  622         printf("prefetch abort handler: %p %p\n", (void*)tf->tf_pc,
  623             (void*)tf->tf_usr_lr);
  624 #endif
  625 
  626         td = curthread;
  627         p = td->td_proc;
  628         PCPU_INC(cnt.v_trap);
  629 
  630         if (TRAP_USERMODE(tf)) {
  631                 td->td_frame = tf;
  632                 if (td->td_ucred != td->td_proc->p_ucred)
  633                         cred_update_thread(td);
  634         }
  635         fault_pc = tf->tf_pc;
  636         if (td->td_md.md_spinlock_count == 0) {
  637                 if (__predict_true(tf->tf_spsr & PSR_I) == 0)
  638                         enable_interrupts(PSR_I);
  639                 if (__predict_true(tf->tf_spsr & PSR_F) == 0)
  640                         enable_interrupts(PSR_F);
  641         }
  642 
  643         /* Prefetch aborts cannot happen in kernel mode */
  644         if (__predict_false(!TRAP_USERMODE(tf)))
  645                 dab_fatal(tf, 0, tf->tf_pc, NULL, &ksig);
  646         td->td_pticks = 0;
  647 
  648 
  649         /* Ok validate the address, can only execute in USER space */
  650         if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS ||
  651             (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) {
  652                 ksig.signb = SIGSEGV;
  653                 ksig.code = 0;
  654                 goto do_trapsignal;
  655         }
  656 
  657         map = &td->td_proc->p_vmspace->vm_map;
  658         va = trunc_page(fault_pc);
  659 
  660         /*
  661          * See if the pmap can handle this fault on its own...
  662          */
  663 #ifdef DEBUG
  664         last_fault_code = -1;
  665 #endif
  666         if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ, 1))
  667                 goto out;
  668 
  669         if (map != kernel_map) {
  670                 PROC_LOCK(p);
  671                 p->p_lock++;
  672                 PROC_UNLOCK(p);
  673         }
  674 
  675         error = vm_fault(map, va, VM_PROT_READ | VM_PROT_EXECUTE,
  676             VM_FAULT_NORMAL);
  677         if (map != kernel_map) {
  678                 PROC_LOCK(p);
  679                 p->p_lock--;
  680                 PROC_UNLOCK(p);
  681         }
  682 
  683         if (__predict_true(error == 0))
  684                 goto out;
  685 
  686         if (error == ENOMEM) {
  687                 printf("VM: pid %d (%s), uid %d killed: "
  688                     "out of swap\n", td->td_proc->p_pid, td->td_name,
  689                     (td->td_proc->p_ucred) ?
  690                      td->td_proc->p_ucred->cr_uid : -1);
  691                 ksig.signb = SIGKILL;
  692         } else {
  693                 ksig.signb = SIGSEGV;
  694         }
  695         ksig.code = 0;
  696 
  697 do_trapsignal:
  698         call_trapsignal(td, ksig.signb, ksig.code);
  699 
  700 out:
  701         userret(td, tf);
  702 
  703 }
  704 
  705 extern int badaddr_read_1(const uint8_t *, uint8_t *);
  706 extern int badaddr_read_2(const uint16_t *, uint16_t *);
  707 extern int badaddr_read_4(const uint32_t *, uint32_t *);
  708 /*
  709  * Tentatively read an 8, 16, or 32-bit value from 'addr'.
  710  * If the read succeeds, the value is written to 'rptr' and zero is returned.
  711  * Else, return EFAULT.
  712  */
  713 int
  714 badaddr_read(void *addr, size_t size, void *rptr)
  715 {
  716         union {
  717                 uint8_t v1;
  718                 uint16_t v2;
  719                 uint32_t v4;
  720         } u;
  721         int rv;
  722 
  723         cpu_drain_writebuf();
  724 
  725         /* Read from the test address. */
  726         switch (size) {
  727         case sizeof(uint8_t):
  728                 rv = badaddr_read_1(addr, &u.v1);
  729                 if (rv == 0 && rptr)
  730                         *(uint8_t *) rptr = u.v1;
  731                 break;
  732 
  733         case sizeof(uint16_t):
  734                 rv = badaddr_read_2(addr, &u.v2);
  735                 if (rv == 0 && rptr)
  736                         *(uint16_t *) rptr = u.v2;
  737                 break;
  738 
  739         case sizeof(uint32_t):
  740                 rv = badaddr_read_4(addr, &u.v4);
  741                 if (rv == 0 && rptr)
  742                         *(uint32_t *) rptr = u.v4;
  743                 break;
  744 
  745         default:
  746                 panic("badaddr: invalid size (%lu)", (u_long) size);
  747         }
  748 
  749         /* Return EFAULT if the address was invalid, else zero */
  750         return (rv);

Cache object: babcb75ea31d747cd40be04db9b0bd5d


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