disas.c

   1 /* General "disassemble this chunk" code.  Used for debugging. */
   2 #include "qemu/osdep.h"
   3 #include "disas/dis-asm.h"
   4 #include "elf.h"
   5 #include "qemu/qemu-print.h"
   6
   7 #include "cpu.h"
   8 #include "disas/disas.h"
   9 #include "disas/capstone.h"
  10
  11 typedef struct CPUDebug {
  12     struct disassemble_info info;
  13     CPUState *cpu;
  14 } CPUDebug;
  15
  16 /* Filled in by elfload.c.  Simplistic, but will do for now. */
  17 struct syminfo *syminfos = NULL;
  18
  19 /*
  20  * Get LENGTH bytes from info's buffer, at host address memaddr.
  21  * Transfer them to myaddr.
  22  */
  23 static int host_read_memory(bfd_vma memaddr, bfd_byte *myaddr, int length,
  24                             struct disassemble_info *info)
  25 {
  26     if (memaddr < info->buffer_vma
  27         || memaddr + length > info->buffer_vma + info->buffer_length) {
  28         /* Out of bounds.  Use EIO because GDB uses it.  */
  29         return EIO;
  30     }
  31     memcpy (myaddr, info->buffer + (memaddr - info->buffer_vma), length);
  32     return 0;
  33 }
  34
  35 /*
  36  * Get LENGTH bytes from info's buffer, at target address memaddr.
  37  * Transfer them to myaddr.
  38  */
  39 static int target_read_memory(bfd_vma memaddr, bfd_byte *myaddr, int length,
  40                               struct disassemble_info *info)
  41 {
  42     CPUDebug *s = container_of(info, CPUDebug, info);
  43     int r = cpu_memory_rw_debug(s->cpu, memaddr, myaddr, length, 0);
  44     return r ? EIO : 0;
  45 }
  46
  47 /*
  48  * Print an error message.  We can assume that this is in response to
  49  * an error return from {host,target}_read_memory.
  50  */
  51 static void perror_memory(int status, bfd_vma memaddr,
  52                           struct disassemble_info *info)
  53 {
  54     if (status != EIO) {
  55         /* Can't happen.  */
  56         info->fprintf_func(info->stream, "Unknown error %d\n", status);
  57     } else {
  58         /* Address between memaddr and memaddr + len was out of bounds.  */
  59         info->fprintf_func(info->stream,
  60                            "Address 0x%" PRIx64 " is out of bounds.\n",
  61                            memaddr);
  62     }
  63 }
  64
  65 /* Print address in hex. */
  66 static void print_address(bfd_vma addr, struct disassemble_info *info)
  67 {
  68     info->fprintf_func(info->stream, "0x%" PRIx64, addr);
  69 }
  70
  71 /* Print address in hex, truncated to the width of a host virtual address. */
  72 static void host_print_address(bfd_vma addr, struct disassemble_info *info)
  73 {
  74     print_address((uintptr_t)addr, info);
  75 }
  76
  77 /* Stub prevents some fruitless earching in optabs disassemblers. */
  78 static int symbol_at_address(bfd_vma addr, struct disassemble_info *info)
  79 {
  80     return 1;
  81 }
  82
  83 static int print_insn_objdump(bfd_vma pc, disassemble_info *info,
  84                               const char *prefix)
  85 {
  86     int i, n = info->buffer_length;
  87     uint8_t *buf = g_malloc(n);
  88
  89     info->read_memory_func(pc, buf, n, info);
  90
  91     for (i = 0; i < n; ++i) {
  92         if (i % 32 == 0) {
  93             info->fprintf_func(info->stream, "\n%s: ", prefix);
  94         }
  95         info->fprintf_func(info->stream, "%02x", buf[i]);
  96     }
  97
  98     g_free(buf);
  99     return n;
 100 }
 101
 102 static int print_insn_od_host(bfd_vma pc, disassemble_info *info)
 103 {
 104     return print_insn_objdump(pc, info, "OBJD-H");
 105 }
 106
 107 static int print_insn_od_target(bfd_vma pc, disassemble_info *info)
 108 {
 109     return print_insn_objdump(pc, info, "OBJD-T");
 110 }
 111
 112 static void initialize_debug(CPUDebug *s)
 113 {
 114     memset(s, 0, sizeof(*s));
 115     s->info.arch = bfd_arch_unknown;
 116     s->info.cap_arch = -1;
 117     s->info.cap_insn_unit = 4;
 118     s->info.cap_insn_split = 4;
 119     s->info.memory_error_func = perror_memory;
 120     s->info.symbol_at_address_func = symbol_at_address;
 121 }
 122
 123 static void initialize_debug_target(CPUDebug *s, CPUState *cpu)
 124 {
 125     initialize_debug(s);
 126
 127     s->cpu = cpu;
 128     s->info.read_memory_func = target_read_memory;
 129     s->info.print_address_func = print_address;
 130 #ifdef TARGET_WORDS_BIGENDIAN
 131     s->info.endian = BFD_ENDIAN_BIG;
 132 #else
 133     s->info.endian = BFD_ENDIAN_LITTLE;
 134 #endif
 135
 136     CPUClass *cc = CPU_GET_CLASS(cpu);
 137     if (cc->disas_set_info) {
 138         cc->disas_set_info(cpu, &s->info);
 139     }
 140 }
 141
 142 static void initialize_debug_host(CPUDebug *s)
 143 {
 144     initialize_debug(s);
 145
 146     s->info.read_memory_func = host_read_memory;
 147     s->info.print_address_func = host_print_address;
 148 #ifdef HOST_WORDS_BIGENDIAN
 149     s->info.endian = BFD_ENDIAN_BIG;
 150 #else
 151     s->info.endian = BFD_ENDIAN_LITTLE;
 152 #endif
 153 #if defined(CONFIG_TCG_INTERPRETER)
 154     s->info.print_insn = print_insn_tci;
 155 #elif defined(__i386__)
 156     s->info.mach = bfd_mach_i386_i386;
 157     s->info.print_insn = print_insn_i386;
 158     s->info.cap_arch = CS_ARCH_X86;
 159     s->info.cap_mode = CS_MODE_32;
 160     s->info.cap_insn_unit = 1;
 161     s->info.cap_insn_split = 8;
 162 #elif defined(__x86_64__)
 163     s->info.mach = bfd_mach_x86_64;
 164     s->info.print_insn = print_insn_i386;
 165     s->info.cap_arch = CS_ARCH_X86;
 166     s->info.cap_mode = CS_MODE_64;
 167     s->info.cap_insn_unit = 1;
 168     s->info.cap_insn_split = 8;
 169 #elif defined(_ARCH_PPC)
 170     s->info.disassembler_options = (char *)"any";
 171     s->info.print_insn = print_insn_ppc;
 172     s->info.cap_arch = CS_ARCH_PPC;
 173 # ifdef _ARCH_PPC64
 174     s->info.cap_mode = CS_MODE_64;
 175 # endif
 176 #elif defined(__riscv) && defined(CONFIG_RISCV_DIS)
 177 #if defined(_ILP32) || (__riscv_xlen == 32)
 178     s->info.print_insn = print_insn_riscv32;
 179 #elif defined(_LP64)
 180     s->info.print_insn = print_insn_riscv64;
 181 #else
 182 #error unsupported RISC-V ABI
 183 #endif
 184 #elif defined(__aarch64__)
 185     s->info.cap_arch = CS_ARCH_ARM64;
 186 # ifdef CONFIG_ARM_A64_DIS
 187     s->info.print_insn = print_insn_arm_a64;
 188 # endif
 189 #elif defined(__alpha__)
 190     s->info.print_insn = print_insn_alpha;
 191 #elif defined(__sparc__)
 192     s->info.print_insn = print_insn_sparc;
 193     s->info.mach = bfd_mach_sparc_v9b;
 194 #elif defined(__arm__)
 195     /* TCG only generates code for arm mode.  */
 196     s->info.print_insn = print_insn_arm;
 197     s->info.cap_arch = CS_ARCH_ARM;
 198 #elif defined(__MIPSEB__)
 199     s->info.print_insn = print_insn_big_mips;
 200 #elif defined(__MIPSEL__)
 201     s->info.print_insn = print_insn_little_mips;
 202 #elif defined(__m68k__)
 203     s->info.print_insn = print_insn_m68k;
 204 #elif defined(__s390__)
 205     s->info.print_insn = print_insn_s390;
 206     s->info.cap_arch = CS_ARCH_SYSZ;
 207     s->info.cap_insn_unit = 2;
 208     s->info.cap_insn_split = 6;
 209 #elif defined(__hppa__)
 210     s->info.print_insn = print_insn_hppa;
 211 #endif
 212 }
 213
 214 /* Disassemble this for me please... (debugging).  */
 215 void target_disas(FILE *out, CPUState *cpu, target_ulong code,
 216                   target_ulong size)
 217 {
 218     target_ulong pc;
 219     int count;
 220     CPUDebug s;
 221
 222     initialize_debug_target(&s, cpu);
 223     s.info.fprintf_func = fprintf;
 224     s.info.stream = out;
 225     s.info.buffer_vma = code;
 226     s.info.buffer_length = size;
 227
 228     if (s.info.cap_arch >= 0 && cap_disas_target(&s.info, code, size)) {
 229         return;
 230     }
 231
 232     if (s.info.print_insn == NULL) {
 233         s.info.print_insn = print_insn_od_target;
 234     }
 235
 236     for (pc = code; size > 0; pc += count, size -= count) {
 237         fprintf(out, "0x" TARGET_FMT_lx ":  ", pc);
 238         count = s.info.print_insn(pc, &s.info);
 239         fprintf(out, "\n");
 240         if (count < 0)
 241             break;
 242         if (size < count) {
 243             fprintf(out,
 244                     "Disassembler disagrees with translator over instruction "
 245                     "decoding\n"
 246                     "Please report this to qemu-devel@nongnu.org\n");
 247             break;
 248         }
 249     }
 250 }
 251
 252 static int plugin_printf(FILE *stream, const char *fmt, ...)
 253 {
 254     /* We abuse the FILE parameter to pass a GString. */
 255     GString *s = (GString *)stream;
 256     int initial_len = s->len;
 257     va_list va;
 258
 259     va_start(va, fmt);
 260     g_string_append_vprintf(s, fmt, va);
 261     va_end(va);
 262
 263     return s->len - initial_len;
 264 }
 265
 266 static void plugin_print_address(bfd_vma addr, struct disassemble_info *info)
 267 {
 268     /* does nothing */
 269 }
 270
 271
 272 /*
 273  * We should only be dissembling one instruction at a time here. If
 274  * there is left over it usually indicates the front end has read more
 275  * bytes than it needed.
 276  */
 277 char *plugin_disas(CPUState *cpu, uint64_t addr, size_t size)
 278 {
 279     CPUDebug s;
 280     GString *ds = g_string_new(NULL);
 281
 282     initialize_debug_target(&s, cpu);
 283     s.info.fprintf_func = plugin_printf;
 284     s.info.stream = (FILE *)ds;  /* abuse this slot */
 285     s.info.buffer_vma = addr;
 286     s.info.buffer_length = size;
 287     s.info.print_address_func = plugin_print_address;
 288
 289     if (s.info.cap_arch >= 0 && cap_disas_plugin(&s.info, addr, size)) {
 290         ; /* done */
 291     } else if (s.info.print_insn) {
 292         s.info.print_insn(addr, &s.info);
 293     } else {
 294         ; /* cannot disassemble -- return empty string */
 295     }
 296
 297     /* Return the buffer, freeing the GString container.  */
 298     return g_string_free(ds, false);
 299 }
 300
 301 /* Disassemble this for me please... (debugging). */
 302 void disas(FILE *out, const void *code, unsigned long size)
 303 {
 304     uintptr_t pc;
 305     int count;
 306     CPUDebug s;
 307
 308     initialize_debug_host(&s);
 309     s.info.fprintf_func = fprintf;
 310     s.info.stream = out;
 311     s.info.buffer = code;
 312     s.info.buffer_vma = (uintptr_t)code;
 313     s.info.buffer_length = size;
 314
 315     if (s.info.cap_arch >= 0 && cap_disas_host(&s.info, code, size)) {
 316         return;
 317     }
 318
 319     if (s.info.print_insn == NULL) {
 320         s.info.print_insn = print_insn_od_host;
 321     }
 322     for (pc = (uintptr_t)code; size > 0; pc += count, size -= count) {
 323         fprintf(out, "0x%08" PRIxPTR ":  ", pc);
 324         count = s.info.print_insn(pc, &s.info);
 325         fprintf(out, "\n");
 326         if (count < 0) {
 327             break;
 328         }
 329     }
 330
 331 }
 332
 333 /* Look up symbol for debugging purpose.  Returns "" if unknown. */
 334 const char *lookup_symbol(target_ulong orig_addr)
 335 {
 336     const char *symbol = "";
 337     struct syminfo *s;
 338
 339     for (s = syminfos; s; s = s->next) {
 340         symbol = s->lookup_symbol(s, orig_addr);
 341         if (symbol[0] != '\0') {
 342             break;
 343         }
 344     }
 345
 346     return symbol;
 347 }
 348
 349 #if !defined(CONFIG_USER_ONLY)
 350
 351 #include "monitor/monitor.h"
 352
 353 static int
 354 physical_read_memory(bfd_vma memaddr, bfd_byte *myaddr, int length,
 355                      struct disassemble_info *info)
 356 {
 357     CPUDebug *s = container_of(info, CPUDebug, info);
 358     MemTxResult res;
 359
 360     res = address_space_read(s->cpu->as, memaddr, MEMTXATTRS_UNSPECIFIED,
 361                              myaddr, length);
 362     return res == MEMTX_OK ? 0 : EIO;
 363 }
 364
 365 /* Disassembler for the monitor.  */
 366 void monitor_disas(Monitor *mon, CPUState *cpu,
 367                    target_ulong pc, int nb_insn, int is_physical)
 368 {
 369     int count, i;
 370     CPUDebug s;
 371
 372     initialize_debug_target(&s, cpu);
 373     s.info.fprintf_func = qemu_fprintf;
 374     if (is_physical) {
 375         s.info.read_memory_func = physical_read_memory;
 376     }
 377     s.info.buffer_vma = pc;
 378
 379     if (s.info.cap_arch >= 0 && cap_disas_monitor(&s.info, pc, nb_insn)) {
 380         return;
 381     }
 382
 383     if (!s.info.print_insn) {
 384         monitor_printf(mon, "0x" TARGET_FMT_lx
 385                        ": Asm output not supported on this arch\n", pc);
 386         return;
 387     }
 388
 389     for(i = 0; i < nb_insn; i++) {
 390         monitor_printf(mon, "0x" TARGET_FMT_lx ":  ", pc);
 391         count = s.info.print_insn(pc, &s.info);
 392         monitor_printf(mon, "\n");
 393         if (count < 0)
 394             break;
 395         pc += count;
 396     }
 397 }
 398 #endif