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) & 0xe000) == 0xe000) && \
   97                                  (((insn) & 0x1800) != 0))
   98 /*
   99  * Coprocessor, Advanced SIMD, and
  100  * Floating-point instructions on page A6-251
  101  * OP1 == 01 OR 11
  102  * OP2 == 1xxxxxx
  103  */
  104 #define THUMB_COPROC_INSN(insn) (((insn) & (3 << 26)) == (3 << 26))
  105 /*
  106  * Advanced SIMD element or structure
  107  * load/store instructions on page A7-275
  108  * OP1 == 11
  109  * OP2 == 001xxx0
  110 */
  111 #define THUMB_VFP_INSN(insn)    (((insn) & (0x1F1 << 20)) == (0x190 << 20))
  112 #define THUMB_COPROC(insn)      (((insn) >> 8) & 0xf)
  113 
  114 #define COPROC_VFP      10
  115 
  116 static int gdb_trapper(u_int, u_int, struct trapframe *, int);
  117 
  118 LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS];
  119 
  120 void *
  121 install_coproc_handler(int coproc, undef_handler_t handler)
  122 {
  123         struct undefined_handler *uh;
  124 
  125         KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc"));
  126         KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */
  127 
  128         /* XXX: M_TEMP??? */
  129         uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK);
  130         uh->uh_handler = handler;
  131         install_coproc_handler_static(coproc, uh);
  132         return uh;
  133 }
  134 
  135 void
  136 install_coproc_handler_static(int coproc, struct undefined_handler *uh)
  137 {
  138 
  139         LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link);
  140 }
  141 
  142 void
  143 remove_coproc_handler(void *cookie)
  144 {
  145         struct undefined_handler *uh = cookie;
  146 
  147         LIST_REMOVE(uh, uh_link);
  148         free(uh, M_TEMP);
  149 }
  150 
  151 static int
  152 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code)
  153 {
  154         struct thread *td;
  155         ksiginfo_t ksi;
  156         int error;
  157 
  158         td = (curthread == NULL) ? &thread0 : curthread;
  159 
  160         if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) {
  161                 if (code == FAULT_USER) {
  162                         ksiginfo_init_trap(&ksi);
  163                         ksi.ksi_signo = SIGTRAP;
  164                         ksi.ksi_code = TRAP_BRKPT;
  165                         ksi.ksi_addr = (u_int32_t *)addr;
  166                         trapsignal(td, &ksi);
  167                         return 0;
  168                 }
  169 #if 0
  170 #ifdef KGDB
  171                 return !kgdb_trap(T_BREAKPOINT, frame);
  172 #endif
  173 #endif
  174         }
  175 
  176         if (code == FAULT_USER) {
  177                 /* TODO: No support for ptrace from Thumb-2 */
  178                 if ((frame->tf_spsr & PSR_T) == 0 &&
  179                     insn == PTRACE_BREAKPOINT) {
  180                         PROC_LOCK(td->td_proc);
  181                         _PHOLD(td->td_proc);
  182                         error = ptrace_clear_single_step(td);
  183                         _PRELE(td->td_proc);
  184                         PROC_UNLOCK(td->td_proc);
  185                         if (error == 0) {
  186                                 ksiginfo_init_trap(&ksi);
  187                                 ksi.ksi_signo = SIGTRAP;
  188                                 ksi.ksi_code = TRAP_TRACE;
  189                                 ksi.ksi_addr = (u_int32_t *)addr;
  190                                 trapsignal(td, &ksi);
  191                                 return (0);
  192                         }
  193                 }
  194         }
  195 
  196         return 1;
  197 }
  198 
  199 static struct undefined_handler gdb_uh;
  200 
  201 void
  202 undefined_init(void)
  203 {
  204         int loop;
  205 
  206         /* Not actually necessary -- the initialiser is just NULL */
  207         for (loop = 0; loop < MAX_COPROCS; ++loop)
  208                 LIST_INIT(&undefined_handlers[loop]);
  209 
  210         /* Install handler for GDB breakpoints */
  211         gdb_uh.uh_handler = gdb_trapper;
  212         install_coproc_handler_static(0, &gdb_uh);
  213 }
  214 
  215 void
  216 undefinedinstruction(struct trapframe *frame)
  217 {
  218         struct thread *td;
  219         u_int fault_pc;
  220         int fault_instruction;
  221         int fault_code;
  222         int coprocessor;
  223         struct undefined_handler *uh;
  224 #ifdef VERBOSE_ARM32
  225         int s;
  226 #endif
  227         ksiginfo_t ksi;
  228 
  229         /* Enable interrupts if they were enabled before the exception. */
  230         if (__predict_true(frame->tf_spsr & PSR_I) == 0)
  231                 enable_interrupts(PSR_I);
  232         if (__predict_true(frame->tf_spsr & PSR_F) == 0)
  233                 enable_interrupts(PSR_F);
  234 
  235         VM_CNT_INC(v_trap);
  236 
  237         fault_pc = frame->tf_pc;
  238 
  239         /*
  240          * Get the current thread/proc structure or thread0/proc0 if there is
  241          * none.
  242          */
  243         td = curthread == NULL ? &thread0 : curthread;
  244 
  245         coprocessor = 0;
  246         if ((frame->tf_spsr & PSR_T) == 0) {
  247                 /*
  248                  * Make sure the program counter is correctly aligned so we
  249                  * don't take an alignment fault trying to read the opcode.
  250                  */
  251                 if (__predict_false((fault_pc & 3) != 0)) {
  252                         ksiginfo_init_trap(&ksi);
  253                         ksi.ksi_signo = SIGILL;
  254                         ksi.ksi_code = ILL_ILLADR;
  255                         ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
  256                         trapsignal(td, &ksi);
  257                         userret(td, frame);
  258                         return;
  259                 }
  260 
  261                 /*
  262                  * Should use fuword() here .. but in the interests of
  263                  * squeezing every bit of speed we will just use ReadWord().
  264                  * We know the instruction can be read as was just executed
  265                  * so this will never fail unless the kernel is screwed up
  266                  * in which case it does not really matter does it ?
  267                  */
  268 
  269                 fault_instruction = *(u_int32_t *)fault_pc;
  270 
  271                 /* Check for coprocessor instruction */
  272 
  273                 /*
  274                  * According to the datasheets you only need to look at bit
  275                  * 27 of the instruction to tell the difference between and
  276                  * undefined instruction and a coprocessor instruction
  277                  * following an undefined instruction trap.
  278                  */
  279 
  280                 if (ARM_COPROC_INSN(fault_instruction))
  281                         coprocessor = ARM_COPROC(fault_instruction);
  282                 else {          /* check for special instructions */
  283                         if (ARM_VFP_INSN(fault_instruction))
  284                                 coprocessor = COPROC_VFP; /* vfp / simd */
  285                 }
  286         } else {
  287 #if __ARM_ARCH >= 7
  288                 fault_instruction = *(uint16_t *)fault_pc;
  289                 if (THUMB_32BIT_INSN(fault_instruction)) {
  290                         fault_instruction <<= 16;
  291                         fault_instruction |= *(uint16_t *)(fault_pc + 2);
  292 
  293                         /* Coprocessor, Advanced SIMD and Floating-point */
  294                         if (THUMB_COPROC_INSN(fault_instruction))
  295                                 coprocessor = THUMB_COPROC(fault_instruction);
  296                         else {
  297                                 /* Advanced SIMD load/store */
  298                                 if (THUMB_VFP_INSN(fault_instruction))
  299                                         coprocessor = COPROC_VFP; /* SIMD */
  300                         }
  301                 }
  302 #else
  303                 /*
  304                  * No support for Thumb-2 on this cpu
  305                  */
  306                 ksiginfo_init_trap(&ksi);
  307                 ksi.ksi_signo = SIGILL;
  308                 ksi.ksi_code = ILL_ILLADR;
  309                 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
  310                 trapsignal(td, &ksi);
  311                 userret(td, frame);
  312                 return;
  313 #endif
  314         }
  315 
  316         if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) {
  317                 /*
  318                  * Modify the fault_code to reflect the USR/SVC state at
  319                  * time of fault.
  320                  */
  321                 fault_code = FAULT_USER;
  322                 td->td_frame = frame;
  323         } else
  324                 fault_code = 0;
  325 
  326         /* OK this is were we do something about the instruction. */
  327         LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link)
  328             if (uh->uh_handler(fault_pc, fault_instruction, frame,
  329                                fault_code) == 0)
  330                     break;
  331 
  332         if (uh == NULL && (fault_code & FAULT_USER)) {
  333                 /* Fault has not been handled */
  334                 ksiginfo_init_trap(&ksi);
  335                 ksi.ksi_signo = SIGILL;
  336                 ksi.ksi_code = ILL_ILLOPC;
  337                 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
  338                 trapsignal(td, &ksi);
  339         }
  340 
  341         if ((fault_code & FAULT_USER) == 0) {
  342                 if (fault_instruction == KERNEL_BREAKPOINT) {
  343 #ifdef KDB
  344                         kdb_trap(T_BREAKPOINT, 0, frame);
  345 #else
  346                         printf("No debugger in kernel.\n");
  347 #endif
  348                         return;
  349                 }
  350                 else
  351                         panic("Undefined instruction in kernel (0x%08x).\n",
  352                             fault_instruction);
  353         }
  354 
  355         userret(td, frame);
  356 }
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FreeBSD/Linux Kernel Cross Reference sys/arm/arm/undefined.c

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