disas.c

   1 /* General "disassemble this chunk" code.  Used for debugging. */
   2 #include "config.h"
   3 #include "dis-asm.h"
   4 #include "disas.h"
   5 #include "elf.h"
   6 #include <errno.h>
   7
   8 #include "cpu.h"
   9 #include "exec-all.h"
  10
  11 /* Filled in by elfload.c.  Simplistic, but will do for now. */
  12 unsigned int disas_num_syms;
  13 void *disas_symtab;
  14 const char *disas_strtab;
  15
  16 /* Get LENGTH bytes from info's buffer, at target address memaddr.
  17    Transfer them to myaddr.  */
  18 int
  19 buffer_read_memory (memaddr, myaddr, length, info)
  20      bfd_vma memaddr;
  21      bfd_byte *myaddr;
  22      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     memcpy (myaddr, info->buffer + (memaddr - info->buffer_vma), length);
  30     return 0;
  31 }
  32
  33 #if !defined(CONFIG_USER_ONLY)
  34 /* Get LENGTH bytes from info's buffer, at target address memaddr.
  35    Transfer them to myaddr.  */
  36 static int
  37 target_read_memory (memaddr, myaddr, length, info)
  38      bfd_vma memaddr;
  39      bfd_byte *myaddr;
  40      int length;
  41      struct disassemble_info *info;
  42 {
  43     int i;
  44     for(i = 0; i < length; i++) {
  45         myaddr[i] = ldub_code((void *)((long)memaddr + i));
  46     }
  47     return 0;
  48 }
  49 #endif
  50
  51 /* Print an error message.  We can assume that this is in response to
  52    an error return from buffer_read_memory.  */
  53 void
  54 perror_memory (status, memaddr, info)
  55      int status;
  56      bfd_vma memaddr;
  57      struct disassemble_info *info;
  58 {
  59   if (status != EIO)
  60     /* Can't happen.  */
  61     (*info->fprintf_func) (info->stream, "Unknown error %d\n", status);
  62   else
  63     /* Actually, address between memaddr and memaddr + len was
  64        out of bounds.  */
  65     (*info->fprintf_func) (info->stream,
  66                            "Address 0x%llx is out of bounds.\n", memaddr);
  67 }
  68
  69 /* This could be in a separate file, to save miniscule amounts of space
  70    in statically linked executables.  */
  71
  72 /* Just print the address is hex.  This is included for completeness even
  73    though both GDB and objdump provide their own (to print symbolic
  74    addresses).  */
  75
  76 void
  77 generic_print_address (addr, info)
  78      bfd_vma addr;
  79      struct disassemble_info *info;
  80 {
  81   (*info->fprintf_func) (info->stream, "0x%llx", addr);
  82 }
  83
  84 /* Just return the given address.  */
  85
  86 int
  87 generic_symbol_at_address (addr, info)
  88      bfd_vma addr;
  89      struct disassemble_info * info;
  90 {
  91   return 1;
  92 }
  93
  94 bfd_vma bfd_getl32 (const bfd_byte *addr)
  95 {
  96   unsigned long v;
  97
  98   v = (unsigned long) addr[0];
  99   v |= (unsigned long) addr[1] << 8;
 100   v |= (unsigned long) addr[2] << 16;
 101   v |= (unsigned long) addr[3] << 24;
 102   return (bfd_vma) v;
 103 }
 104
 105 bfd_vma bfd_getb32 (const bfd_byte *addr)
 106 {
 107   unsigned long v;
 108
 109   v = (unsigned long) addr[0] << 24;
 110   v |= (unsigned long) addr[1] << 16;
 111   v |= (unsigned long) addr[2] << 8;
 112   v |= (unsigned long) addr[3];
 113   return (bfd_vma) v;
 114 }
 115
 116 /* Disassemble this for me please... (debugging). 'flags' is only used
 117    for i386: non zero means 16 bit code */
 118 void disas(FILE *out, void *code, unsigned long size, int is_host, int flags)
 119 {
 120     uint8_t *pc;
 121     int count;
 122     struct disassemble_info disasm_info;
 123     int (*print_insn)(bfd_vma pc, disassemble_info *info);
 124
 125     INIT_DISASSEMBLE_INFO(disasm_info, out, fprintf);
 126
 127 #if !defined(CONFIG_USER_ONLY)
 128     if (!is_host) {
 129         disasm_info.read_memory_func = target_read_memory;
 130     }
 131 #endif
 132
 133     disasm_info.buffer = code;
 134     disasm_info.buffer_vma = (unsigned long)code;
 135     disasm_info.buffer_length = size;
 136
 137     if (is_host) {
 138 #ifdef WORDS_BIGENDIAN
 139         disasm_info.endian = BFD_ENDIAN_BIG;
 140 #else
 141         disasm_info.endian = BFD_ENDIAN_LITTLE;
 142 #endif
 143 #ifdef __i386__
 144         disasm_info.mach = bfd_mach_i386_i386;
 145         print_insn = print_insn_i386;
 146 #elif defined(__powerpc__)
 147         print_insn = print_insn_ppc;
 148 #elif defined(__alpha__)
 149         print_insn = print_insn_alpha;
 150 #elif defined(__sparc__)
 151         print_insn = print_insn_sparc;
 152 #elif defined(__arm__)
 153         print_insn = print_insn_arm;
 154 #else
 155         fprintf(out, "Asm output not supported on this arch\n");
 156         return;
 157 #endif
 158     } else {
 159 #ifdef TARGET_WORDS_BIGENDIAN
 160         disasm_info.endian = BFD_ENDIAN_BIG;
 161 #else
 162         disasm_info.endian = BFD_ENDIAN_LITTLE;
 163 #endif
 164 #if defined(TARGET_I386)
 165         if (!flags)
 166             disasm_info.mach = bfd_mach_i386_i386;
 167         else
 168             disasm_info.mach = bfd_mach_i386_i8086;
 169         print_insn = print_insn_i386;
 170 #elif defined(TARGET_ARM)
 171         print_insn = print_insn_arm;
 172 #elif defined(TARGET_SPARC)
 173         print_insn = print_insn_sparc;
 174 #else
 175         fprintf(out, "Asm output not supported on this arch\n");
 176         return;
 177 #endif
 178     }
 179
 180     for (pc = code; pc < (uint8_t *)code + size; pc += count) {
 181         fprintf(out, "0x%08lx:  ", (long)pc);
 182 #ifdef __arm__
 183         /* since data are included in the code, it is better to
 184            display code data too */
 185         if (is_host) {
 186             fprintf(out, "%08x  ", (int)bfd_getl32((const bfd_byte *)pc));
 187         }
 188 #endif
 189         count = print_insn((unsigned long)pc, &disasm_info);
 190         fprintf(out, "\n");
 191         if (count < 0)
 192             break;
 193     }
 194 }
 195
 196 /* Look up symbol for debugging purpose.  Returns "" if unknown. */
 197 const char *lookup_symbol(void *orig_addr)
 198 {
 199     unsigned int i;
 200     /* Hack, because we know this is x86. */
 201     Elf32_Sym *sym = disas_symtab;
 202
 203     for (i = 0; i < disas_num_syms; i++) {
 204         if (sym[i].st_shndx == SHN_UNDEF
 205             || sym[i].st_shndx >= SHN_LORESERVE)
 206             continue;
 207
 208         if (ELF_ST_TYPE(sym[i].st_info) != STT_FUNC)
 209             continue;
 210
 211         if ((long)orig_addr >= sym[i].st_value
 212             && (long)orig_addr < sym[i].st_value + sym[i].st_size)
 213             return disas_strtab + sym[i].st_name;
 214     }
 215     return "";
 216 }