usr/src/lib/libdisasm/sparc/dis_sparc.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*
  28  * Copyright 2007 Jason King.  All rights reserved.
  29  * Use is subject to license terms.
  30  */
  31
  32 /*
  33  * The sparc disassembler is mostly straightforward, each instruction is
  34  * represented by an inst_t structure.  The inst_t definitions are organized
  35  * into tables.  The tables are correspond to the opcode maps documented in the
  36  * various sparc architecture manuals.  Each table defines the bit range of the
  37  * instruction whose value act as an index into the array of instructions.  A
  38  * table can also refer to another table if needed.  Each table also contains
  39  * a function pointer of type format_fcn that knows how to output the
  40  * instructions in the table, as well as handle any synthetic instructions
  41  *
  42  * Unfortunately, the changes from sparcv8 -> sparcv9 not only include new
  43  * instructions, they sometimes renamed or just reused the same instruction to
  44  * do different operations (i.e. the sparcv8 coprocessor instructions).  To
  45  * accommodate this, each table can define an overlay table.  The overlay table
  46  * is a list of (table index, architecture, new instruction definition) values.
  47  *
  48  *
  49  * Traversal starts with the first table,
  50  *   get index value from the instruction
  51  *   if an relevant overlay entry exists for this index,
  52  *        grab the overlay definition
  53  *   else
  54  *        grab the definition from the array (corresponding to the index value)
  55  *
  56  * If the entry is an instruction,
  57  *     call print function of instruction.
  58  * If the entry is a pointer to another table
  59  *     traverse the table
  60  * If not valid,
  61  *     return an error
  62  *
  63  *
  64  * To keep dis happy, for sparc, instead of actually returning an error, if
  65  * the instruction cannot be disassembled, we instead merely place the value
  66  * of the instruction into the output buffer.
  67  *
  68  * Adding new instructions:
  69  *
  70  * With the above information, it hopefully makes it clear how to add support
  71  * for decoding new instructions.  Presumably, with new instructions will come
  72  * a new dissassembly mode (I.e. DIS_SPARC_V8, DIS_SPARC_V9, etc.).
  73  *
  74  * If the dissassembled format does not correspond to one of the existing
  75  * formats, a new formatter will have to be written.  The 'flags' value of
  76  * inst_t is intended to instruct the corresponding formatter about how to
  77  * output the instruction.
  78  *
  79  * If the corresponding entry in the correct table is currently unoccupied,
  80  * simply replace the INVALID entry with the correct definition.  The INST and
  81  * TABLE macros are suggested to be used for this.  If there is already an
  82  * instruction defined, then the entry must be placed in an overlay table.  If
  83  * no overlay table exists for the instruction table, one will need to be
  84  * created.
  85  */
  86
  87 #include <libdisasm.h>
  88 #include <stdlib.h>
  89 #include <stdio.h>
  90 #include <sys/types.h>
  91 #include <sys/byteorder.h>
  92 #include <string.h>
  93
  94 #include "libdisasm_impl.h"
  95 #include "dis_sparc.h"
  96
  97 static const inst_t *dis_get_overlay(dis_handle_t *, const table_t *,
  98     uint32_t);
  99 static uint32_t dis_get_bits(uint32_t, int, int);
 100
 101 #if !defined(DIS_STANDALONE)
 102 static void do_binary(uint32_t);
 103 #endif /* DIS_STANDALONE */
 104
 105 dis_handle_t *
 106 dis_handle_create(int flags, void *data, dis_lookup_f lookup_func,
 107     dis_read_f read_func)
 108 {
 109
 110 #if !defined(DIS_STANDALONE)
 111         char *opt = NULL;
 112         char *opt2, *save, *end;
 113 #endif
 114         dis_handle_t *dhp;
 115
 116         if ((flags & (DIS_SPARC_V8|DIS_SPARC_V9|DIS_SPARC_V9_SGI)) == 0) {
 117                 (void) dis_seterrno(E_DIS_INVALFLAG);
 118                 return (NULL);
 119         }
 120
 121         if ((dhp = dis_zalloc(sizeof (struct dis_handle))) == NULL) {
 122                 (void) dis_seterrno(E_DIS_NOMEM);
 123                 return (NULL);
 124         }
 125
 126         dhp->dh_lookup = lookup_func;
 127         dhp->dh_read = read_func;
 128         dhp->dh_flags = flags;
 129         dhp->dh_data = data;
 130         dhp->dh_debug = DIS_DEBUG_COMPAT;
 131
 132 #if !defined(DIS_STANDALONE)
 133
 134         opt = getenv("_LIBDISASM_DEBUG");
 135         if (opt == NULL)
 136                 return (dhp);
 137
 138         opt2 = strdup(opt);
 139         if (opt2 == NULL) {
 140                 dis_handle_destroy(dhp);
 141                 (void) dis_seterrno(E_DIS_NOMEM);
 142                 return (NULL);
 143         }
 144         save = opt2;
 145
 146         while (opt2 != NULL) {
 147                 end = strchr(opt2, ',');
 148
 149                 if (end != 0)
 150                         *end++ = '\0';
 151
 152                 if (strcasecmp("synth-all", opt2) == 0)
 153                         dhp->dh_debug |= DIS_DEBUG_SYN_ALL;
 154
 155                 if (strcasecmp("compat", opt2) == 0)
 156                         dhp->dh_debug |= DIS_DEBUG_COMPAT;
 157
 158                 if (strcasecmp("synth-none", opt2) == 0)
 159                         dhp->dh_debug &= ~(DIS_DEBUG_SYN_ALL|DIS_DEBUG_COMPAT);
 160
 161                 if (strcasecmp("binary", opt2) == 0)
 162                         dhp->dh_debug |= DIS_DEBUG_PRTBIN;
 163
 164                 if (strcasecmp("format", opt2) == 0)
 165                         dhp->dh_debug |= DIS_DEBUG_PRTFMT;
 166
 167                 if (strcasecmp("all", opt2) == 0)
 168                         dhp->dh_debug = DIS_DEBUG_ALL;
 169
 170                 if (strcasecmp("none", opt2) == 0)
 171                         dhp->dh_debug = DIS_DEBUG_NONE;
 172
 173                 opt2 = end;
 174         }
 175         free(save);
 176 #endif /* DIS_STANDALONE */
 177         return (dhp);
 178 }
 179
 180 void
 181 dis_handle_destroy(dis_handle_t *dhp)
 182 {
 183         dis_free(dhp, sizeof (dis_handle_t));
 184 }
 185
 186 void
 187 dis_set_data(dis_handle_t *dhp, void *data)
 188 {
 189         dhp->dh_data = data;
 190 }
 191
 192 void
 193 dis_flags_set(dis_handle_t *dhp, int f)
 194 {
 195         dhp->dh_flags |= f;
 196 }
 197
 198 void
 199 dis_flags_clear(dis_handle_t *dhp, int f)
 200 {
 201         dhp->dh_flags &= ~f;
 202 }
 203
 204 /* ARGSUSED */
 205 int
 206 dis_max_instrlen(dis_handle_t *dhp)
 207 {
 208         return (4);
 209 }
 210
 211 /*
 212  * The dis_i386.c comment for this says it returns the previous instruction,
 213  * however, I'm fairly sure it's actually returning the _address_ of the
 214  * nth previous instruction.
 215  */
 216 /* ARGSUSED */
 217 uint64_t
 218 dis_previnstr(dis_handle_t *dhp, uint64_t pc, int n)
 219 {
 220         if (n <= 0)
 221                 return (pc);
 222
 223         if (pc < n)
 224                 return (pc);
 225
 226         return (pc - n*4);
 227 }
 228
 229 /* ARGSUSED */
 230 int
 231 dis_instrlen(dis_handle_t *dhp, uint64_t pc)
 232 {
 233         return (4);
 234 }
 235
 236 int
 237 dis_disassemble(dis_handle_t *dhp, uint64_t addr, char *buf, size_t buflen)
 238 {
 239         const table_t *tp = &initial_table;
 240         const inst_t *inp = NULL;
 241
 242         uint32_t instr;
 243         uint32_t idx = 0;
 244
 245         if (dhp->dh_read(dhp->dh_data, addr, &instr, sizeof (instr)) !=
 246             sizeof (instr))
 247                 return (-1);
 248
 249         dhp->dh_buf    = buf;
 250         dhp->dh_buflen = buflen;
 251         dhp->dh_addr   = addr;
 252
 253         buf[0] = '\0';
 254
 255         /* this allows sparc code to be tested on x86 */
 256         instr = BE_32(instr);
 257
 258 #if !defined(DIS_STANDALONE)
 259         if ((dhp->dh_debug & DIS_DEBUG_PRTBIN) != 0)
 260                 do_binary(instr);
 261 #endif /* DIS_STANDALONE */
 262
 263         /* CONSTCOND */
 264         while (1) {
 265                 idx = dis_get_bits(instr, tp->tbl_field, tp->tbl_len);
 266                 inp = &tp->tbl_inp[idx];
 267
 268                 inp = dis_get_overlay(dhp, tp, idx);
 269
 270                 if ((inp->in_type == INST_NONE) ||
 271                     ((inp->in_arch & dhp->dh_flags) == 0))
 272                         goto error;
 273
 274                 if (inp->in_type == INST_TBL) {
 275                         tp = inp->in_data.in_tbl;
 276                         continue;
 277                 }
 278
 279                 break;
 280         }
 281
 282         if (tp->tbl_fmt(dhp, instr, inp, idx) == 0)
 283                 return (0);
 284
 285 error:
 286
 287         (void) snprintf(buf, buflen,
 288             ((dhp->dh_flags & DIS_OCTAL) != 0) ? "0%011lo" : "0x%08lx",
 289             instr);
 290
 291         return (0);
 292 }
 293
 294 static uint32_t
 295 dis_get_bits(uint32_t instr, int offset, int length)
 296 {
 297         uint32_t mask, val;
 298         int i;
 299
 300         for (i = 0, mask = 0; i < length; ++i)
 301                 mask |= (1UL << i);
 302
 303         mask = mask << (offset - length + 1);
 304
 305         val = instr & mask;
 306
 307         val = val >> (offset - length + 1);
 308
 309         return (val);
 310 }
 311
 312 static const inst_t *
 313 dis_get_overlay(dis_handle_t *dhp, const table_t *tp, uint32_t idx)
 314 {
 315         const inst_t *ip = &tp->tbl_inp[idx];
 316         int i;
 317
 318         if (tp->tbl_ovp == NULL)
 319                 return (ip);
 320
 321         for (i = 0; tp->tbl_ovp[i].ov_idx != -1; ++i) {
 322                 if (tp->tbl_ovp[i].ov_idx != idx)
 323                         continue;
 324
 325                 if ((tp->tbl_ovp[i].ov_inst.in_arch & dhp->dh_flags) == 0)
 326                         continue;
 327
 328                 ip = &tp->tbl_ovp[i].ov_inst;
 329                 break;
 330         }
 331
 332         return (ip);
 333 }
 334
 335 #if !defined(DIS_STANDALONE)
 336 static void
 337 do_binary(uint32_t instr)
 338 {
 339         (void) fprintf(stderr, "DISASM: ");
 340         prt_binary(instr, 32);
 341         (void) fprintf(stderr, "\n");
 342 }
 343 #endif /* DIS_STANDALONE */