undefined.c

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    1 /*      $NetBSD: undefined.c,v 1.22 2003/11/29 22:21:29 bjh21 Exp $     */
    2 
    3 /*-
    4  * SPDX-License-Identifier: BSD-4-Clause
    5  *
    6  * Copyright (c) 2001 Ben Harris.
    7  * Copyright (c) 1995 Mark Brinicombe.
    8  * Copyright (c) 1995 Brini.
    9  * All rights reserved.
   10  *
   11  * This code is derived from software written for Brini by Mark Brinicombe
   12  *
   13  * Redistribution and use in source and binary forms, with or without
   14  * modification, are permitted provided that the following conditions
   15  * are met:
   16  * 1. Redistributions of source code must retain the above copyright
   17  *    notice, this list of conditions and the following disclaimer.
   18  * 2. Redistributions in binary form must reproduce the above copyright
   19  *    notice, this list of conditions and the following disclaimer in the
   20  *    documentation and/or other materials provided with the distribution.
   21  * 3. All advertising materials mentioning features or use of this software
   22  *    must display the following acknowledgement:
   23  *      This product includes software developed by Brini.
   24  * 4. The name of the company nor the name of the author may be used to
   25  *    endorse or promote products derived from this software without specific
   26  *    prior written permission.
   27  *
   28  * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED
   29  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   30  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   31  * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
   32  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   33  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   34  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   38  * SUCH DAMAGE.
   39  *
   40  * RiscBSD kernel project
   41  *
   42  * undefined.c
   43  *
   44  * Fault handler
   45  *
   46  * Created      : 06/01/95
   47  */
   48 
   49 #include "opt_ddb.h"
   50 
   51 #include <sys/cdefs.h>
   52 __FBSDID("$FreeBSD$");
   53 
   54 #include <sys/param.h>
   55 #include <sys/malloc.h>
   56 #include <sys/queue.h>
   57 #include <sys/signal.h>
   58 #include <sys/systm.h>
   59 #include <sys/proc.h>
   60 #include <sys/syslog.h>
   61 #include <sys/vmmeter.h>
   62 #include <sys/lock.h>
   63 #include <sys/mutex.h>
   64 #include <sys/signalvar.h>
   65 #include <sys/ptrace.h>
   66 #include <sys/vmmeter.h>
   67 #ifdef KDB
   68 #include <sys/kdb.h>
   69 #endif
   70 
   71 #include <vm/vm.h>
   72 #include <vm/vm_extern.h>
   73 
   74 #include <machine/armreg.h>
   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 #endif
   86 
   87 #ifdef KDB
   88 #include <machine/db_machdep.h>
   89 #endif
   90 
   91 #define ARM_COPROC_INSN(insn)   (((insn) & (1 << 27)) != 0)
   92 #define ARM_VFP_INSN(insn)      ((((insn) & 0xfe000000) == 0xf2000000) || \
   93     (((insn) & 0xff100000) == 0xf4000000))
   94 #define ARM_COPROC(insn)        (((insn) >> 8) & 0xf)
   95 
   96 #define THUMB_32BIT_INSN(insn)  ((insn) >= 0xe800)
   97 #define THUMB_COPROC_INSN(insn) (((insn) & (3 << 26)) == (3 << 26))
   98 #define THUMB_COPROC_UNDEFINED(insn) (((insn) & 0x3e << 20) == 0)
   99 #define THUMB_VFP_INSN(insn)    (((insn) & (3 << 24)) == (3 << 24))
  100 #define THUMB_COPROC(insn)      (((insn) >> 8) & 0xf)
  101 
  102 #define COPROC_VFP      10
  103 
  104 static int gdb_trapper(u_int, u_int, struct trapframe *, int);
  105 
  106 LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS];
  107 
  108 void *
  109 install_coproc_handler(int coproc, undef_handler_t handler)
  110 {
  111         struct undefined_handler *uh;
  112 
  113         KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc"));
  114         KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */
  115 
  116         /* XXX: M_TEMP??? */
  117         uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK);
  118         uh->uh_handler = handler;
  119         install_coproc_handler_static(coproc, uh);
  120         return uh;
  121 }
  122 
  123 void
  124 install_coproc_handler_static(int coproc, struct undefined_handler *uh)
  125 {
  126 
  127         LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link);
  128 }
  129 
  130 void
  131 remove_coproc_handler(void *cookie)
  132 {
  133         struct undefined_handler *uh = cookie;
  134 
  135         LIST_REMOVE(uh, uh_link);
  136         free(uh, M_TEMP);
  137 }
  138 
  139 static int
  140 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code)
  141 {
  142         struct thread *td;
  143         ksiginfo_t ksi;
  144         int error;
  145 
  146         td = (curthread == NULL) ? &thread0 : curthread;
  147 
  148         if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) {
  149                 if (code == FAULT_USER) {
  150                         ksiginfo_init_trap(&ksi);
  151                         ksi.ksi_signo = SIGTRAP;
  152                         ksi.ksi_code = TRAP_BRKPT;
  153                         ksi.ksi_addr = (u_int32_t *)addr;
  154                         trapsignal(td, &ksi);
  155                         return 0;
  156                 }
  157 #if 0
  158 #ifdef KGDB
  159                 return !kgdb_trap(T_BREAKPOINT, frame);
  160 #endif
  161 #endif
  162         }
  163 
  164         if (code == FAULT_USER) {
  165                 /* TODO: No support for ptrace from Thumb-2 */
  166                 if ((frame->tf_spsr & PSR_T) == 0 &&
  167                     insn == PTRACE_BREAKPOINT) {
  168                         PROC_LOCK(td->td_proc);
  169                         _PHOLD(td->td_proc);
  170                         error = ptrace_clear_single_step(td);
  171                         _PRELE(td->td_proc);
  172                         PROC_UNLOCK(td->td_proc);
  173                         if (error == 0) {
  174                                 ksiginfo_init_trap(&ksi);
  175                                 ksi.ksi_signo = SIGTRAP;
  176                                 ksi.ksi_code = TRAP_TRACE;
  177                                 ksi.ksi_addr = (u_int32_t *)addr;
  178                                 trapsignal(td, &ksi);
  179                                 return (0);
  180                         }
  181                 }
  182         }
  183 
  184         return 1;
  185 }
  186 
  187 static struct undefined_handler gdb_uh;
  188 
  189 void
  190 undefined_init(void)
  191 {
  192         int loop;
  193 
  194         /* Not actually necessary -- the initialiser is just NULL */
  195         for (loop = 0; loop < MAX_COPROCS; ++loop)
  196                 LIST_INIT(&undefined_handlers[loop]);
  197 
  198         /* Install handler for GDB breakpoints */
  199         gdb_uh.uh_handler = gdb_trapper;
  200         install_coproc_handler_static(0, &gdb_uh);
  201 }
  202 
  203 void
  204 undefinedinstruction(struct trapframe *frame)
  205 {
  206         struct thread *td;
  207         u_int fault_pc;
  208         int fault_instruction;
  209         int fault_code;
  210         int coprocessor;
  211         struct undefined_handler *uh;
  212 #ifdef VERBOSE_ARM32
  213         int s;
  214 #endif
  215         ksiginfo_t ksi;
  216 
  217         /* Enable interrupts if they were enabled before the exception. */
  218         if (__predict_true(frame->tf_spsr & PSR_I) == 0)
  219                 enable_interrupts(PSR_I);
  220         if (__predict_true(frame->tf_spsr & PSR_F) == 0)
  221                 enable_interrupts(PSR_F);
  222 
  223         VM_CNT_INC(v_trap);
  224 
  225         fault_pc = frame->tf_pc;
  226 
  227         /*
  228          * Get the current thread/proc structure or thread0/proc0 if there is
  229          * none.
  230          */
  231         td = curthread == NULL ? &thread0 : curthread;
  232 
  233         coprocessor = 0;
  234         if ((frame->tf_spsr & PSR_T) == 0) {
  235                 /*
  236                  * Make sure the program counter is correctly aligned so we
  237                  * don't take an alignment fault trying to read the opcode.
  238                  */
  239                 if (__predict_false((fault_pc & 3) != 0)) {
  240                         ksiginfo_init_trap(&ksi);
  241                         ksi.ksi_signo = SIGILL;
  242                         ksi.ksi_code = ILL_ILLADR;
  243                         ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
  244                         trapsignal(td, &ksi);
  245                         userret(td, frame);
  246                         return;
  247                 }
  248 
  249                 /*
  250                  * Should use fuword() here .. but in the interests of
  251                  * squeezing every bit of speed we will just use ReadWord().
  252                  * We know the instruction can be read as was just executed
  253                  * so this will never fail unless the kernel is screwed up
  254                  * in which case it does not really matter does it ?
  255                  */
  256 
  257                 fault_instruction = *(u_int32_t *)fault_pc;
  258 
  259                 /* Check for coprocessor instruction */
  260 
  261                 /*
  262                  * According to the datasheets you only need to look at bit
  263                  * 27 of the instruction to tell the difference between and
  264                  * undefined instruction and a coprocessor instruction
  265                  * following an undefined instruction trap.
  266                  */
  267 
  268                 if (ARM_COPROC_INSN(fault_instruction))
  269                         coprocessor = ARM_COPROC(fault_instruction);
  270                 else {          /* check for special instructions */
  271                         if (ARM_VFP_INSN(fault_instruction))
  272                                 coprocessor = COPROC_VFP; /* vfp / simd */
  273                 }
  274         } else {
  275 #if __ARM_ARCH >= 7
  276                 fault_instruction = *(uint16_t *)fault_pc;
  277                 if (THUMB_32BIT_INSN(fault_instruction)) {
  278                         fault_instruction <<= 16;
  279                         fault_instruction |= *(uint16_t *)(fault_pc + 2);
  280 
  281                         /*
  282                          * Is it a Coprocessor, Advanced SIMD, or
  283                          * Floating-point instruction.
  284                          */
  285                         if (THUMB_COPROC_INSN(fault_instruction)) {
  286                                 if (THUMB_COPROC_UNDEFINED(fault_instruction)) {
  287                                         /* undefined insn */
  288                                 } else if (THUMB_VFP_INSN(fault_instruction))
  289                                         coprocessor = COPROC_VFP;
  290                                 else
  291                                         coprocessor =
  292                                             THUMB_COPROC(fault_instruction);
  293                         }
  294                 }
  295 #else
  296                 /*
  297                  * No support for Thumb-2 on this cpu
  298                  */
  299                 ksiginfo_init_trap(&ksi);
  300                 ksi.ksi_signo = SIGILL;
  301                 ksi.ksi_code = ILL_ILLADR;
  302                 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
  303                 trapsignal(td, &ksi);
  304                 userret(td, frame);
  305                 return;
  306 #endif
  307         }
  308 
  309         if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) {
  310                 /*
  311                  * Modify the fault_code to reflect the USR/SVC state at
  312                  * time of fault.
  313                  */
  314                 fault_code = FAULT_USER;
  315                 td->td_frame = frame;
  316         } else
  317                 fault_code = 0;
  318 
  319         /* OK this is were we do something about the instruction. */
  320         LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link)
  321             if (uh->uh_handler(fault_pc, fault_instruction, frame,
  322                                fault_code) == 0)
  323                     break;
  324 
  325         if (uh == NULL && (fault_code & FAULT_USER)) {
  326                 /* Fault has not been handled */
  327                 ksiginfo_init_trap(&ksi);
  328                 ksi.ksi_signo = SIGILL;
  329                 ksi.ksi_code = ILL_ILLOPC;
  330                 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
  331                 trapsignal(td, &ksi);
  332         }
  333 
  334         if ((fault_code & FAULT_USER) == 0) {
  335                 if (fault_instruction == KERNEL_BREAKPOINT) {
  336 #ifdef KDB
  337                         kdb_trap(T_BREAKPOINT, 0, frame);
  338 #else
  339                         printf("No debugger in kernel.\n");
  340 #endif
  341                         return;
  342                 }
  343                 else
  344                         panic("Undefined instruction in kernel.\n");
  345         }
  346 
  347         userret(td, frame);
  348 }
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FreeBSD/Linux Kernel Cross Reference sys/arm/arm/undefined.c

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