The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/arm/arm/undefined.c

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    1 /*      $NetBSD: undefined.c,v 1.22 2003/11/29 22:21:29 bjh21 Exp $     */
    2 
    3 /*-
    4  * Copyright (c) 2001 Ben Harris.
    5  * Copyright (c) 1995 Mark Brinicombe.
    6  * Copyright (c) 1995 Brini.
    7  * All rights reserved.
    8  *
    9  * This code is derived from software written for Brini by Mark Brinicombe
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  * 3. All advertising materials mentioning features or use of this software
   20  *    must display the following acknowledgement:
   21  *      This product includes software developed by Brini.
   22  * 4. The name of the company nor the name of the author may be used to
   23  *    endorse or promote products derived from this software without specific
   24  *    prior written permission.
   25  *
   26  * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED
   27  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   28  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   29  * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
   30  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   31  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   32  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   36  * SUCH DAMAGE.
   37  *
   38  * RiscBSD kernel project
   39  *
   40  * undefined.c
   41  *
   42  * Fault handler
   43  *
   44  * Created      : 06/01/95
   45  */
   46 
   47 
   48 #include "opt_ddb.h"
   49 
   50 #include <sys/cdefs.h>
   51 __FBSDID("$FreeBSD: releng/8.1/sys/arm/arm/undefined.c 184205 2008-10-23 15:53:51Z des $");
   52 
   53 #include <sys/param.h>
   54 #include <sys/malloc.h>
   55 #include <sys/queue.h>
   56 #include <sys/signal.h>
   57 #include <sys/systm.h>
   58 #include <sys/proc.h>
   59 #include <sys/syslog.h>
   60 #include <sys/vmmeter.h>
   61 #include <sys/lock.h>
   62 #include <sys/mutex.h>
   63 #include <sys/signalvar.h>
   64 #include <sys/ptrace.h>
   65 #ifdef KDB
   66 #include <sys/kdb.h>
   67 #endif
   68 #ifdef FAST_FPE
   69 #include <sys/acct.h>
   70 #endif
   71 
   72 #include <vm/vm.h>
   73 #include <vm/vm_extern.h>
   74 
   75 #include <machine/asm.h>
   76 #include <machine/cpu.h>
   77 #include <machine/frame.h>
   78 #include <machine/undefined.h>
   79 #include <machine/trap.h>
   80 
   81 #include <machine/disassem.h>
   82 
   83 #ifdef DDB
   84 #include <ddb/db_output.h>
   85 #include <machine/db_machdep.h>
   86 #endif
   87 
   88 #ifdef acorn26
   89 #include <machine/machdep.h>
   90 #endif
   91 
   92 static int gdb_trapper(u_int, u_int, struct trapframe *, int);
   93 #ifdef FAST_FPE
   94 extern int want_resched;
   95 #endif
   96 
   97 LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS];
   98 
   99 
  100 void *
  101 install_coproc_handler(int coproc, undef_handler_t handler)
  102 {
  103         struct undefined_handler *uh;
  104 
  105         KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc"));
  106         KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */
  107 
  108         /* XXX: M_TEMP??? */
  109         uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK);
  110         uh->uh_handler = handler;
  111         install_coproc_handler_static(coproc, uh);
  112         return uh;
  113 }
  114 
  115 void
  116 install_coproc_handler_static(int coproc, struct undefined_handler *uh)
  117 {
  118 
  119         LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link);
  120 }
  121 
  122 void
  123 remove_coproc_handler(void *cookie)
  124 {
  125         struct undefined_handler *uh = cookie;
  126 
  127         LIST_REMOVE(uh, uh_link);
  128         free(uh, M_TEMP);
  129 }
  130 
  131 
  132 static int
  133 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code)
  134 {
  135         struct thread *td;
  136         ksiginfo_t ksi;
  137 
  138         td = (curthread == NULL) ? &thread0 : curthread;
  139 
  140         if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) {
  141                 if (code == FAULT_USER) {
  142                         ksiginfo_init_trap(&ksi);
  143                         ksi.ksi_signo = SIGTRAP;
  144                         ksi.ksi_code = TRAP_BRKPT;
  145                         ksi.ksi_addr = (u_int32_t *)addr;
  146                         trapsignal(td, &ksi);
  147                         return 0;
  148                 }
  149 #if 0
  150 #ifdef KGDB
  151                 return !kgdb_trap(T_BREAKPOINT, frame);
  152 #endif
  153 #endif
  154         }
  155         return 1;
  156 }
  157 
  158 static struct undefined_handler gdb_uh;
  159 
  160 void
  161 undefined_init()
  162 {
  163         int loop;
  164 
  165         /* Not actually necessary -- the initialiser is just NULL */
  166         for (loop = 0; loop < MAX_COPROCS; ++loop)
  167                 LIST_INIT(&undefined_handlers[loop]);
  168 
  169         /* Install handler for GDB breakpoints */
  170         gdb_uh.uh_handler = gdb_trapper;
  171         install_coproc_handler_static(0, &gdb_uh);
  172 }
  173 
  174 
  175 void
  176 undefinedinstruction(trapframe_t *frame)
  177 {
  178         struct thread *td;
  179         u_int fault_pc;
  180         int fault_instruction;
  181         int fault_code;
  182         int coprocessor;
  183         struct undefined_handler *uh;
  184 #ifdef VERBOSE_ARM32
  185         int s;
  186 #endif
  187         ksiginfo_t ksi;
  188 
  189         /* Enable interrupts if they were enabled before the exception. */
  190         if (!(frame->tf_spsr & I32_bit))
  191                 enable_interrupts(I32_bit|F32_bit);
  192 
  193         frame->tf_pc -= INSN_SIZE;
  194         PCPU_INC(cnt.v_trap);
  195 
  196         fault_pc = frame->tf_pc;
  197 
  198         /* 
  199          * Get the current thread/proc structure or thread0/proc0 if there is 
  200          * none.
  201          */
  202         td = curthread == NULL ? &thread0 : curthread;
  203 
  204         /*
  205          * Make sure the program counter is correctly aligned so we
  206          * don't take an alignment fault trying to read the opcode.
  207          */
  208         if (__predict_false((fault_pc & 3) != 0)) {
  209                 ksiginfo_init_trap(&ksi);
  210                 ksi.ksi_signo = SIGILL;
  211                 ksi.ksi_code = ILL_ILLADR;
  212                 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
  213                 trapsignal(td, &ksi);
  214                 userret(td, frame);
  215                 return;
  216         }
  217 
  218         /*
  219          * Should use fuword() here .. but in the interests of squeezing every
  220          * bit of speed we will just use ReadWord(). We know the instruction
  221          * can be read as was just executed so this will never fail unless the
  222          * kernel is screwed up in which case it does not really matter does
  223          * it ?
  224          */
  225 
  226         fault_instruction = *(u_int32_t *)fault_pc;
  227 
  228         /* Update vmmeter statistics */
  229 #if 0
  230         uvmexp.traps++;
  231 #endif
  232         /* Check for coprocessor instruction */
  233 
  234         /*
  235          * According to the datasheets you only need to look at bit 27 of the
  236          * instruction to tell the difference between and undefined
  237          * instruction and a coprocessor instruction following an undefined
  238          * instruction trap.
  239          */
  240 
  241         if ((fault_instruction & (1 << 27)) != 0)
  242                 coprocessor = (fault_instruction >> 8) & 0x0f;
  243         else
  244                 coprocessor = 0;
  245 
  246         if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) {
  247                 /*
  248                  * Modify the fault_code to reflect the USR/SVC state at
  249                  * time of fault.
  250                  */
  251                 fault_code = FAULT_USER;
  252                 td->td_frame = frame;
  253         } else
  254                 fault_code = 0;
  255 
  256         /* OK this is were we do something about the instruction. */
  257         LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link)
  258             if (uh->uh_handler(fault_pc, fault_instruction, frame,
  259                                fault_code) == 0)
  260                     break;
  261 
  262         if (fault_code & FAULT_USER && fault_instruction == PTRACE_BREAKPOINT) {
  263                 PROC_LOCK(td->td_proc);
  264                 _PHOLD(td->td_proc);
  265                 ptrace_clear_single_step(td);
  266                 _PRELE(td->td_proc);
  267                 PROC_UNLOCK(td->td_proc);
  268                 return;
  269         }
  270 
  271         if (uh == NULL && (fault_code & FAULT_USER)) {
  272                 /* Fault has not been handled */
  273                 ksiginfo_init_trap(&ksi);
  274                 ksi.ksi_signo = SIGILL;
  275                 ksi.ksi_code = ILL_ILLOPC;
  276                 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
  277                 trapsignal(td, &ksi);
  278         }
  279 
  280         if ((fault_code & FAULT_USER) == 0) {
  281                 if (fault_instruction == KERNEL_BREAKPOINT) {
  282 #ifdef KDB
  283                         kdb_trap(T_BREAKPOINT, 0, frame);
  284 #else
  285                         printf("No debugger in kernel.\n");
  286 #endif
  287                         return;
  288                 } else
  289                         panic("Undefined instruction in kernel.\n");
  290         }
  291 
  292 #ifdef FAST_FPE
  293         /* Optimised exit code */
  294         {
  295 
  296                 /*
  297                  * Check for reschedule request, at the moment there is only
  298                  * 1 ast so this code should always be run
  299                  */
  300 
  301                 if (want_resched) {
  302                         /*
  303                          * We are being preempted.
  304                          */
  305                         preempt(0);
  306                 }
  307 
  308                 /* Invoke MI userret code */
  309                 mi_userret(td);
  310 
  311 #if 0
  312                 l->l_priority = l->l_usrpri;
  313 
  314                 curcpu()->ci_schedstate.spc_curpriority = l->l_priority;
  315 #endif
  316         }
  317 
  318 #else
  319         userret(td, frame);
  320 #endif
  321 }

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