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