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 */