aboutsummaryrefslogtreecommitdiff
path: root/disas.c
blob: 5325b7e6be67577da9493381a27ea03fcb33c224 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
/* General "disassemble this chunk" code.  Used for debugging. */
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "disas/bfd.h"
#include "elf.h"

#include "cpu.h"
#include "disas/disas.h"
#include "disas/capstone.h"

typedef struct CPUDebug {
    struct disassemble_info info;
    CPUState *cpu;
} CPUDebug;

/* Filled in by elfload.c.  Simplistic, but will do for now. */
struct syminfo *syminfos = NULL;

/* Get LENGTH bytes from info's buffer, at target address memaddr.
   Transfer them to myaddr.  */
int
buffer_read_memory(bfd_vma memaddr, bfd_byte *myaddr, int length,
                   struct disassemble_info *info)
{
    if (memaddr < info->buffer_vma
        || memaddr + length > info->buffer_vma + info->buffer_length)
        /* Out of bounds.  Use EIO because GDB uses it.  */
        return EIO;
    memcpy (myaddr, info->buffer + (memaddr - info->buffer_vma), length);
    return 0;
}

/* Get LENGTH bytes from info's buffer, at target address memaddr.
   Transfer them to myaddr.  */
static int
target_read_memory (bfd_vma memaddr,
                    bfd_byte *myaddr,
                    int length,
                    struct disassemble_info *info)
{
    CPUDebug *s = container_of(info, CPUDebug, info);

    cpu_memory_rw_debug(s->cpu, memaddr, myaddr, length, 0);
    return 0;
}

/* Print an error message.  We can assume that this is in response to
   an error return from buffer_read_memory.  */
void
perror_memory (int status, bfd_vma memaddr, struct disassemble_info *info)
{
  if (status != EIO)
    /* Can't happen.  */
    (*info->fprintf_func) (info->stream, "Unknown error %d\n", status);
  else
    /* Actually, address between memaddr and memaddr + len was
       out of bounds.  */
    (*info->fprintf_func) (info->stream,
			   "Address 0x%" PRIx64 " is out of bounds.\n", memaddr);
}

/* This could be in a separate file, to save minuscule amounts of space
   in statically linked executables.  */

/* Just print the address is hex.  This is included for completeness even
   though both GDB and objdump provide their own (to print symbolic
   addresses).  */

void
generic_print_address (bfd_vma addr, struct disassemble_info *info)
{
    (*info->fprintf_func) (info->stream, "0x%" PRIx64, addr);
}

/* Print address in hex, truncated to the width of a host virtual address. */
static void
generic_print_host_address(bfd_vma addr, struct disassemble_info *info)
{
    uint64_t mask = ~0ULL >> (64 - (sizeof(void *) * 8));
    generic_print_address(addr & mask, info);
}

/* Just return the given address.  */

int
generic_symbol_at_address (bfd_vma addr, struct disassemble_info *info)
{
  return 1;
}

bfd_vma bfd_getl64 (const bfd_byte *addr)
{
  unsigned long long v;

  v = (unsigned long long) addr[0];
  v |= (unsigned long long) addr[1] << 8;
  v |= (unsigned long long) addr[2] << 16;
  v |= (unsigned long long) addr[3] << 24;
  v |= (unsigned long long) addr[4] << 32;
  v |= (unsigned long long) addr[5] << 40;
  v |= (unsigned long long) addr[6] << 48;
  v |= (unsigned long long) addr[7] << 56;
  return (bfd_vma) v;
}

bfd_vma bfd_getl32 (const bfd_byte *addr)
{
  unsigned long v;

  v = (unsigned long) addr[0];
  v |= (unsigned long) addr[1] << 8;
  v |= (unsigned long) addr[2] << 16;
  v |= (unsigned long) addr[3] << 24;
  return (bfd_vma) v;
}

bfd_vma bfd_getb32 (const bfd_byte *addr)
{
  unsigned long v;

  v = (unsigned long) addr[0] << 24;
  v |= (unsigned long) addr[1] << 16;
  v |= (unsigned long) addr[2] << 8;
  v |= (unsigned long) addr[3];
  return (bfd_vma) v;
}

bfd_vma bfd_getl16 (const bfd_byte *addr)
{
  unsigned long v;

  v = (unsigned long) addr[0];
  v |= (unsigned long) addr[1] << 8;
  return (bfd_vma) v;
}

bfd_vma bfd_getb16 (const bfd_byte *addr)
{
  unsigned long v;

  v = (unsigned long) addr[0] << 24;
  v |= (unsigned long) addr[1] << 16;
  return (bfd_vma) v;
}

static int print_insn_objdump(bfd_vma pc, disassemble_info *info,
                              const char *prefix)
{
    int i, n = info->buffer_length;
    uint8_t *buf = g_malloc(n);

    info->read_memory_func(pc, buf, n, info);

    for (i = 0; i < n; ++i) {
        if (i % 32 == 0) {
            info->fprintf_func(info->stream, "\n%s: ", prefix);
        }
        info->fprintf_func(info->stream, "%02x", buf[i]);
    }

    g_free(buf);
    return n;
}

static int print_insn_od_host(bfd_vma pc, disassemble_info *info)
{
    return print_insn_objdump(pc, info, "OBJD-H");
}

static int print_insn_od_target(bfd_vma pc, disassemble_info *info)
{
    return print_insn_objdump(pc, info, "OBJD-T");
}

#ifdef CONFIG_CAPSTONE
/* Temporary storage for the capstone library.  This will be alloced via
   malloc with a size private to the library; thus there's no reason not
   to share this across calls and across host vs target disassembly.  */
static __thread cs_insn *cap_insn;

/* Initialize the Capstone library.  */
/* ??? It would be nice to cache this.  We would need one handle for the
   host and one for the target.  For most targets we can reset specific
   parameters via cs_option(CS_OPT_MODE, new_mode), but we cannot change
   CS_ARCH_* in this way.  Thus we would need to be able to close and
   re-open the target handle with a different arch for the target in order
   to handle AArch64 vs AArch32 mode switching.  */
static cs_err cap_disas_start(disassemble_info *info, csh *handle)
{
    cs_mode cap_mode = info->cap_mode;
    cs_err err;

    cap_mode += (info->endian == BFD_ENDIAN_BIG ? CS_MODE_BIG_ENDIAN
                 : CS_MODE_LITTLE_ENDIAN);

    err = cs_open(info->cap_arch, cap_mode, handle);
    if (err != CS_ERR_OK) {
        return err;
    }

    /* ??? There probably ought to be a better place to put this.  */
    if (info->cap_arch == CS_ARCH_X86) {
        /* We don't care about errors (if for some reason the library
           is compiled without AT&T syntax); the user will just have
           to deal with the Intel syntax.  */
        cs_option(*handle, CS_OPT_SYNTAX, CS_OPT_SYNTAX_ATT);
    }

    /* "Disassemble" unknown insns as ".byte W,X,Y,Z".  */
    cs_option(*handle, CS_OPT_SKIPDATA, CS_OPT_ON);

    /* Allocate temp space for cs_disasm_iter.  */
    if (cap_insn == NULL) {
        cap_insn = cs_malloc(*handle);
        if (cap_insn == NULL) {
            cs_close(handle);
            return CS_ERR_MEM;
        }
    }
    return CS_ERR_OK;
}

static void cap_dump_insn_units(disassemble_info *info, cs_insn *insn,
                                int i, int n)
{
    fprintf_function print = info->fprintf_func;
    FILE *stream = info->stream;

    switch (info->cap_insn_unit) {
    case 4:
        if (info->endian == BFD_ENDIAN_BIG) {
            for (; i < n; i += 4) {
                print(stream, " %08x", ldl_be_p(insn->bytes + i));

            }
        } else {
            for (; i < n; i += 4) {
                print(stream, " %08x", ldl_le_p(insn->bytes + i));
            }
        }
        break;

    case 2:
        if (info->endian == BFD_ENDIAN_BIG) {
            for (; i < n; i += 2) {
                print(stream, " %04x", lduw_be_p(insn->bytes + i));
            }
        } else {
            for (; i < n; i += 2) {
                print(stream, " %04x", lduw_le_p(insn->bytes + i));
            }
        }
        break;

    default:
        for (; i < n; i++) {
            print(stream, " %02x", insn->bytes[i]);
        }
        break;
    }
}

static void cap_dump_insn(disassemble_info *info, cs_insn *insn)
{
    fprintf_function print = info->fprintf_func;
    int i, n, split;

    print(info->stream, "0x%08" PRIx64 ": ", insn->address);

    n = insn->size;
    split = info->cap_insn_split;

    /* Dump the first SPLIT bytes of the instruction.  */
    cap_dump_insn_units(info, insn, 0, MIN(n, split));

    /* Add padding up to SPLIT so that mnemonics line up.  */
    if (n < split) {
        int width = (split - n) / info->cap_insn_unit;
        width *= (2 * info->cap_insn_unit + 1);
        print(info->stream, "%*s", width, "");
    }

    /* Print the actual instruction.  */
    print(info->stream, "  %-8s %s\n", insn->mnemonic, insn->op_str);

    /* Dump any remaining part of the insn on subsequent lines.  */
    for (i = split; i < n; i += split) {
        print(info->stream, "0x%08" PRIx64 ": ", insn->address + i);
        cap_dump_insn_units(info, insn, i, MIN(n, i + split));
        print(info->stream, "\n");
    }
}

/* Disassemble SIZE bytes at PC for the target.  */
static bool cap_disas_target(disassemble_info *info, uint64_t pc, size_t size)
{
    uint8_t cap_buf[1024];
    csh handle;
    cs_insn *insn;
    size_t csize = 0;

    if (cap_disas_start(info, &handle) != CS_ERR_OK) {
        return false;
    }
    insn = cap_insn;

    while (1) {
        size_t tsize = MIN(sizeof(cap_buf) - csize, size);
        const uint8_t *cbuf = cap_buf;

        target_read_memory(pc + csize, cap_buf + csize, tsize, info);
        csize += tsize;
        size -= tsize;

        while (cs_disasm_iter(handle, &cbuf, &csize, &pc, insn)) {
           cap_dump_insn(info, insn);
        }

        /* If the target memory is not consumed, go back for more... */
        if (size != 0) {
            /* ... taking care to move any remaining fractional insn
               to the beginning of the buffer.  */
            if (csize != 0) {
                memmove(cap_buf, cbuf, csize);
            }
            continue;
        }

        /* Since the target memory is consumed, we should not have
           a remaining fractional insn.  */
        if (csize != 0) {
            (*info->fprintf_func)(info->stream,
                "Disassembler disagrees with translator "
                "over instruction decoding\n"
                "Please report this to qemu-devel@nongnu.org\n");
        }
        break;
    }

    cs_close(&handle);
    return true;
}

/* Disassemble SIZE bytes at CODE for the host.  */
static bool cap_disas_host(disassemble_info *info, void *code, size_t size)
{
    csh handle;
    const uint8_t *cbuf;
    cs_insn *insn;
    uint64_t pc;

    if (cap_disas_start(info, &handle) != CS_ERR_OK) {
        return false;
    }
    insn = cap_insn;

    cbuf = code;
    pc = (uintptr_t)code;

    while (cs_disasm_iter(handle, &cbuf, &size, &pc, insn)) {
       cap_dump_insn(info, insn);
    }
    if (size != 0) {
        (*info->fprintf_func)(info->stream,
            "Disassembler disagrees with TCG over instruction encoding\n"
            "Please report this to qemu-devel@nongnu.org\n");
    }

    cs_close(&handle);
    return true;
}

#if !defined(CONFIG_USER_ONLY)
/* Disassemble COUNT insns at PC for the target.  */
static bool cap_disas_monitor(disassemble_info *info, uint64_t pc, int count)
{
    uint8_t cap_buf[32];
    csh handle;
    cs_insn *insn;
    size_t csize = 0;

    if (cap_disas_start(info, &handle) != CS_ERR_OK) {
        return false;
    }
    insn = cap_insn;

    while (1) {
        /* We want to read memory for one insn, but generically we do not
           know how much memory that is.  We have a small buffer which is
           known to be sufficient for all supported targets.  Try to not
           read beyond the page, Just In Case.  For even more simplicity,
           ignore the actual target page size and use a 1k boundary.  If
           that turns out to be insufficient, we'll come back around the
           loop and read more.  */
        uint64_t epc = QEMU_ALIGN_UP(pc + csize + 1, 1024);
        size_t tsize = MIN(sizeof(cap_buf) - csize, epc - pc);
        const uint8_t *cbuf = cap_buf;

        /* Make certain that we can make progress.  */
        assert(tsize != 0);
        info->read_memory_func(pc, cap_buf + csize, tsize, info);
        csize += tsize;

        if (cs_disasm_iter(handle, &cbuf, &csize, &pc, insn)) {
            cap_dump_insn(info, insn);
            if (--count <= 0) {
                break;
            }
        }
        memmove(cap_buf, cbuf, csize);
    }

    cs_close(&handle);
    return true;
}
#endif /* !CONFIG_USER_ONLY */
#else
# define cap_disas_target(i, p, s)  false
# define cap_disas_host(i, p, s)  false
# define cap_disas_monitor(i, p, c)  false
#endif /* CONFIG_CAPSTONE */

/* Disassemble this for me please... (debugging).  */
void target_disas(FILE *out, CPUState *cpu, target_ulong code,
                  target_ulong size)
{
    CPUClass *cc = CPU_GET_CLASS(cpu);
    target_ulong pc;
    int count;
    CPUDebug s;

    INIT_DISASSEMBLE_INFO(s.info, out, fprintf);

    s.cpu = cpu;
    s.info.read_memory_func = target_read_memory;
    s.info.buffer_vma = code;
    s.info.buffer_length = size;
    s.info.print_address_func = generic_print_address;
    s.info.cap_arch = -1;
    s.info.cap_mode = 0;
    s.info.cap_insn_unit = 4;
    s.info.cap_insn_split = 4;

#ifdef TARGET_WORDS_BIGENDIAN
    s.info.endian = BFD_ENDIAN_BIG;
#else
    s.info.endian = BFD_ENDIAN_LITTLE;
#endif

    if (cc->disas_set_info) {
        cc->disas_set_info(cpu, &s.info);
    }

    if (s.info.cap_arch >= 0 && cap_disas_target(&s.info, code, size)) {
        return;
    }

    if (s.info.print_insn == NULL) {
        s.info.print_insn = print_insn_od_target;
    }

    for (pc = code; size > 0; pc += count, size -= count) {
	fprintf(out, "0x" TARGET_FMT_lx ":  ", pc);
	count = s.info.print_insn(pc, &s.info);
	fprintf(out, "\n");
	if (count < 0)
	    break;
        if (size < count) {
            fprintf(out,
                    "Disassembler disagrees with translator over instruction "
                    "decoding\n"
                    "Please report this to qemu-devel@nongnu.org\n");
            break;
        }
    }
}

/* Disassemble this for me please... (debugging). */
void disas(FILE *out, void *code, unsigned long size)
{
    uintptr_t pc;
    int count;
    CPUDebug s;
    int (*print_insn)(bfd_vma pc, disassemble_info *info) = NULL;

    INIT_DISASSEMBLE_INFO(s.info, out, fprintf);
    s.info.print_address_func = generic_print_host_address;

    s.info.buffer = code;
    s.info.buffer_vma = (uintptr_t)code;
    s.info.buffer_length = size;
    s.info.cap_arch = -1;
    s.info.cap_mode = 0;
    s.info.cap_insn_unit = 4;
    s.info.cap_insn_split = 4;

#ifdef HOST_WORDS_BIGENDIAN
    s.info.endian = BFD_ENDIAN_BIG;
#else
    s.info.endian = BFD_ENDIAN_LITTLE;
#endif
#if defined(CONFIG_TCG_INTERPRETER)
    print_insn = print_insn_tci;
#elif defined(__i386__)
    s.info.mach = bfd_mach_i386_i386;
    print_insn = print_insn_i386;
    s.info.cap_arch = CS_ARCH_X86;
    s.info.cap_mode = CS_MODE_32;
    s.info.cap_insn_unit = 1;
    s.info.cap_insn_split = 8;
#elif defined(__x86_64__)
    s.info.mach = bfd_mach_x86_64;
    print_insn = print_insn_i386;
    s.info.cap_arch = CS_ARCH_X86;
    s.info.cap_mode = CS_MODE_64;
    s.info.cap_insn_unit = 1;
    s.info.cap_insn_split = 8;
#elif defined(_ARCH_PPC)
    s.info.disassembler_options = (char *)"any";
    print_insn = print_insn_ppc;
    s.info.cap_arch = CS_ARCH_PPC;
# ifdef _ARCH_PPC64
    s.info.cap_mode = CS_MODE_64;
# endif
#elif defined(__riscv__)
    print_insn = print_insn_riscv;
#elif defined(__aarch64__) && defined(CONFIG_ARM_A64_DIS)
    print_insn = print_insn_arm_a64;
    s.info.cap_arch = CS_ARCH_ARM64;
#elif defined(__alpha__)
    print_insn = print_insn_alpha;
#elif defined(__sparc__)
    print_insn = print_insn_sparc;
    s.info.mach = bfd_mach_sparc_v9b;
#elif defined(__arm__)
    print_insn = print_insn_arm;
    s.info.cap_arch = CS_ARCH_ARM;
    /* TCG only generates code for arm mode.  */
#elif defined(__MIPSEB__)
    print_insn = print_insn_big_mips;
#elif defined(__MIPSEL__)
    print_insn = print_insn_little_mips;
#elif defined(__m68k__)
    print_insn = print_insn_m68k;
#elif defined(__s390__)
    print_insn = print_insn_s390;
#elif defined(__hppa__)
    print_insn = print_insn_hppa;
#endif

    if (s.info.cap_arch >= 0 && cap_disas_host(&s.info, code, size)) {
        return;
    }

    if (print_insn == NULL) {
        print_insn = print_insn_od_host;
    }
    for (pc = (uintptr_t)code; size > 0; pc += count, size -= count) {
        fprintf(out, "0x%08" PRIxPTR ":  ", pc);
        count = print_insn(pc, &s.info);
	fprintf(out, "\n");
	if (count < 0)
	    break;
    }
}

/* Look up symbol for debugging purpose.  Returns "" if unknown. */
const char *lookup_symbol(target_ulong orig_addr)
{
    const char *symbol = "";
    struct syminfo *s;

    for (s = syminfos; s; s = s->next) {
        symbol = s->lookup_symbol(s, orig_addr);
        if (symbol[0] != '\0') {
            break;
        }
    }

    return symbol;
}

#if !defined(CONFIG_USER_ONLY)

#include "monitor/monitor.h"

static int
physical_read_memory(bfd_vma memaddr, bfd_byte *myaddr, int length,
                     struct disassemble_info *info)
{
    cpu_physical_memory_read(memaddr, myaddr, length);
    return 0;
}

/* Disassembler for the monitor.  */
void monitor_disas(Monitor *mon, CPUState *cpu,
                   target_ulong pc, int nb_insn, int is_physical)
{
    CPUClass *cc = CPU_GET_CLASS(cpu);
    int count, i;
    CPUDebug s;

    INIT_DISASSEMBLE_INFO(s.info, (FILE *)mon, monitor_fprintf);

    s.cpu = cpu;
    s.info.read_memory_func
        = (is_physical ? physical_read_memory : target_read_memory);
    s.info.print_address_func = generic_print_address;
    s.info.buffer_vma = pc;
    s.info.cap_arch = -1;
    s.info.cap_mode = 0;
    s.info.cap_insn_unit = 4;
    s.info.cap_insn_split = 4;

#ifdef TARGET_WORDS_BIGENDIAN
    s.info.endian = BFD_ENDIAN_BIG;
#else
    s.info.endian = BFD_ENDIAN_LITTLE;
#endif

    if (cc->disas_set_info) {
        cc->disas_set_info(cpu, &s.info);
    }

    if (s.info.cap_arch >= 0 && cap_disas_monitor(&s.info, pc, nb_insn)) {
        return;
    }

    if (!s.info.print_insn) {
        monitor_printf(mon, "0x" TARGET_FMT_lx
                       ": Asm output not supported on this arch\n", pc);
        return;
    }

    for(i = 0; i < nb_insn; i++) {
	monitor_printf(mon, "0x" TARGET_FMT_lx ":  ", pc);
        count = s.info.print_insn(pc, &s.info);
	monitor_printf(mon, "\n");
	if (count < 0)
	    break;
        pc += count;
    }
}
#endif