drivers/bios_emulator/x86emu/debug.c

   1 /****************************************************************************
   2 *
   3 *                       Realmode X86 Emulator Library
   4 *
   5 *               Copyright (C) 1991-2004 SciTech Software, Inc.
   6 *                    Copyright (C) David Mosberger-Tang
   7 *                      Copyright (C) 1999 Egbert Eich
   8 *
   9 *  ========================================================================
  10 *
  11 *  Permission to use, copy, modify, distribute, and sell this software and
  12 *  its documentation for any purpose is hereby granted without fee,
  13 *  provided that the above copyright notice appear in all copies and that
  14 *  both that copyright notice and this permission notice appear in
  15 *  supporting documentation, and that the name of the authors not be used
  16 *  in advertising or publicity pertaining to distribution of the software
  17 *  without specific, written prior permission.  The authors makes no
  18 *  representations about the suitability of this software for any purpose.
  19 *  It is provided "as is" without express or implied warranty.
  20 *
  21 *  THE AUTHORS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  22 *  INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  23 *  EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  24 *  CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
  25 *  USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
  26 *  OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  27 *  PERFORMANCE OF THIS SOFTWARE.
  28 *
  29 *  ========================================================================
  30 *
  31 * Language:     ANSI C
  32 * Environment:  Any
  33 * Developer:    Kendall Bennett
  34 *
  35 * Description:  This file contains the code to handle debugging of the
  36 *               emulator.
  37 *
  38 ****************************************************************************/
  39
  40 #include <stdarg.h>
  41 #include <common.h>
  42 #include <linux/ctype.h>
  43 #include "x86emu/x86emui.h"
  44
  45 /*----------------------------- Implementation ----------------------------*/
  46
  47 #ifdef DEBUG
  48
  49 static void print_encoded_bytes(u16 s, u16 o);
  50 static void print_decoded_instruction(void);
  51 static int x86emu_parse_line(char *s, int *ps, int *n);
  52
  53 /* should look something like debug's output. */
  54 void X86EMU_trace_regs(void)
  55 {
  56         if (DEBUG_TRACE()) {
  57                 x86emu_dump_regs();
  58         }
  59         if (DEBUG_DECODE() && !DEBUG_DECODE_NOPRINT()) {
  60                 printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
  61                 print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
  62                 print_decoded_instruction();
  63         }
  64 }
  65
  66 void X86EMU_trace_xregs(void)
  67 {
  68         if (DEBUG_TRACE()) {
  69                 x86emu_dump_xregs();
  70         }
  71 }
  72
  73 void x86emu_just_disassemble(void)
  74 {
  75         /*
  76          * This routine called if the flag DEBUG_DISASSEMBLE is set kind
  77          * of a hack!
  78          */
  79         printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
  80         print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
  81         print_decoded_instruction();
  82 }
  83
  84 static void disassemble_forward(u16 seg, u16 off, int n)
  85 {
  86         X86EMU_sysEnv tregs;
  87         int i;
  88         u8 op1;
  89         /*
  90          * hack, hack, hack.  What we do is use the exact machinery set up
  91          * for execution, except that now there is an additional state
  92          * flag associated with the "execution", and we are using a copy
  93          * of the register struct.  All the major opcodes, once fully
  94          * decoded, have the following two steps: TRACE_REGS(r,m);
  95          * SINGLE_STEP(r,m); which disappear if DEBUG is not defined to
  96          * the preprocessor.  The TRACE_REGS macro expands to:
  97          *
  98          * if (debug&DEBUG_DISASSEMBLE)
  99          *     {just_disassemble(); goto EndOfInstruction;}
 100          *     if (debug&DEBUG_TRACE) trace_regs(r,m);
 101          *
 102          * ......  and at the last line of the routine.
 103          *
 104          * EndOfInstruction: end_instr();
 105          *
 106          * Up to the point where TRACE_REG is expanded, NO modifications
 107          * are done to any register EXCEPT the IP register, for fetch and
 108          * decoding purposes.
 109          *
 110          * This was done for an entirely different reason, but makes a
 111          * nice way to get the system to help debug codes.
 112          */
 113         tregs = M;
 114         tregs.x86.R_IP = off;
 115         tregs.x86.R_CS = seg;
 116
 117         /* reset the decoding buffers */
 118         tregs.x86.enc_str_pos = 0;
 119         tregs.x86.enc_pos = 0;
 120
 121         /* turn on the "disassemble only, no execute" flag */
 122         tregs.x86.debug |= DEBUG_DISASSEMBLE_F;
 123
 124         /* DUMP NEXT n instructions to screen in straight_line fashion */
 125         /*
 126          * This looks like the regular instruction fetch stream, except
 127          * that when this occurs, each fetched opcode, upon seeing the
 128          * DEBUG_DISASSEMBLE flag set, exits immediately after decoding
 129          * the instruction.  XXX --- CHECK THAT MEM IS NOT AFFECTED!!!
 130          * Note the use of a copy of the register structure...
 131          */
 132         for (i = 0; i < n; i++) {
 133                 op1 = (*sys_rdb) (((u32) M.x86.R_CS << 4) + (M.x86.R_IP++));
 134                 (x86emu_optab[op1]) (op1);
 135         }
 136         /* end major hack mode. */
 137 }
 138
 139 void x86emu_check_ip_access(void)
 140 {
 141         /* NULL as of now */
 142 }
 143
 144 void x86emu_check_sp_access(void)
 145 {
 146 }
 147
 148 void x86emu_check_mem_access(u32 dummy)
 149 {
 150         /*  check bounds, etc */
 151 }
 152
 153 void x86emu_check_data_access(uint dummy1, uint dummy2)
 154 {
 155         /*  check bounds, etc */
 156 }
 157
 158 void x86emu_inc_decoded_inst_len(int x)
 159 {
 160         M.x86.enc_pos += x;
 161 }
 162
 163 void x86emu_decode_printf(char *x)
 164 {
 165         sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", x);
 166         M.x86.enc_str_pos += strlen(x);
 167 }
 168
 169 void x86emu_decode_printf2(char *x, int y)
 170 {
 171         char temp[100];
 172         sprintf(temp, x, y);
 173         sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", temp);
 174         M.x86.enc_str_pos += strlen(temp);
 175 }
 176
 177 void x86emu_end_instr(void)
 178 {
 179         M.x86.enc_str_pos = 0;
 180         M.x86.enc_pos = 0;
 181 }
 182
 183 static void print_encoded_bytes(u16 s, u16 o)
 184 {
 185         int i;
 186         char buf1[64];
 187         for (i = 0; i < M.x86.enc_pos; i++) {
 188                 sprintf(buf1 + 2 * i, "%02x", fetch_data_byte_abs(s, o + i));
 189         }
 190         printk("%-20s", buf1);
 191 }
 192
 193 static void print_decoded_instruction(void)
 194 {
 195         printk("%s", M.x86.decoded_buf);
 196 }
 197
 198 void x86emu_print_int_vect(u16 iv)
 199 {
 200         u16 seg, off;
 201
 202         if (iv > 256)
 203                 return;
 204         seg = fetch_data_word_abs(0, iv * 4);
 205         off = fetch_data_word_abs(0, iv * 4 + 2);
 206         printk("%04x:%04x ", seg, off);
 207 }
 208
 209 void X86EMU_dump_memory(u16 seg, u16 off, u32 amt)
 210 {
 211         u32 start = off & 0xfffffff0;
 212         u32 end = (off + 16) & 0xfffffff0;
 213         u32 i;
 214         u32 current;
 215
 216         current = start;
 217         while (end <= off + amt) {
 218                 printk("%04x:%04x ", seg, start);
 219                 for (i = start; i < off; i++)
 220                         printk("   ");
 221                 for (; i < end; i++)
 222                         printk("%02x ", fetch_data_byte_abs(seg, i));
 223                 printk("\n");
 224                 start = end;
 225                 end = start + 16;
 226         }
 227 }
 228
 229 void x86emu_single_step(void)
 230 {
 231         char s[1024];
 232         int ps[10];
 233         int ntok;
 234         int cmd;
 235         int done;
 236         int segment;
 237         int offset;
 238         static int breakpoint;
 239         static int noDecode = 1;
 240
 241         char *p;
 242
 243         if (DEBUG_BREAK()) {
 244                 if (M.x86.saved_ip != breakpoint) {
 245                         return;
 246                 } else {
 247                         M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
 248                         M.x86.debug |= DEBUG_TRACE_F;
 249                         M.x86.debug &= ~DEBUG_BREAK_F;
 250                         print_decoded_instruction();
 251                         X86EMU_trace_regs();
 252                 }
 253         }
 254         done = 0;
 255         offset = M.x86.saved_ip;
 256         while (!done) {
 257                 printk("-");
 258                 cmd = x86emu_parse_line(s, ps, &ntok);
 259                 switch (cmd) {
 260                 case 'u':
 261                         disassemble_forward(M.x86.saved_cs, (u16) offset, 10);
 262                         break;
 263                 case 'd':
 264                         if (ntok == 2) {
 265                                 segment = M.x86.saved_cs;
 266                                 offset = ps[1];
 267                                 X86EMU_dump_memory(segment, (u16) offset, 16);
 268                                 offset += 16;
 269                         } else if (ntok == 3) {
 270                                 segment = ps[1];
 271                                 offset = ps[2];
 272                                 X86EMU_dump_memory(segment, (u16) offset, 16);
 273                                 offset += 16;
 274                         } else {
 275                                 segment = M.x86.saved_cs;
 276                                 X86EMU_dump_memory(segment, (u16) offset, 16);
 277                                 offset += 16;
 278                         }
 279                         break;
 280                 case 'c':
 281                         M.x86.debug ^= DEBUG_TRACECALL_F;
 282                         break;
 283                 case 's':
 284                         M.x86.debug ^=
 285                             DEBUG_SVC_F | DEBUG_SYS_F | DEBUG_SYSINT_F;
 286                         break;
 287                 case 'r':
 288                         X86EMU_trace_regs();
 289                         break;
 290                 case 'x':
 291                         X86EMU_trace_xregs();
 292                         break;
 293                 case 'g':
 294                         if (ntok == 2) {
 295                                 breakpoint = ps[1];
 296                                 if (noDecode) {
 297                                         M.x86.debug |= DEBUG_DECODE_NOPRINT_F;
 298                                 } else {
 299                                         M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
 300                                 }
 301                                 M.x86.debug &= ~DEBUG_TRACE_F;
 302                                 M.x86.debug |= DEBUG_BREAK_F;
 303                                 done = 1;
 304                         }
 305                         break;
 306                 case 'q':
 307                         M.x86.debug |= DEBUG_EXIT;
 308                         return;
 309                 case 'P':
 310                         noDecode = (noDecode) ? 0 : 1;
 311                         printk("Toggled decoding to %s\n",
 312                                (noDecode) ? "false" : "true");
 313                         break;
 314                 case 't':
 315                 case 0:
 316                         done = 1;
 317                         break;
 318                 }
 319         }
 320 }
 321
 322 int X86EMU_trace_on(void)
 323 {
 324         return M.x86.debug |= DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F;
 325 }
 326
 327 int X86EMU_trace_off(void)
 328 {
 329         return M.x86.debug &= ~(DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F);
 330 }
 331
 332 static int x86emu_parse_line(char *s, int *ps, int *n)
 333 {
 334         int cmd;
 335
 336         *n = 0;
 337         while (isblank(*s))
 338                 s++;
 339         ps[*n] = *s;
 340         switch (*s) {
 341         case '\n':
 342                 *n += 1;
 343                 return 0;
 344         default:
 345                 cmd = *s;
 346                 *n += 1;
 347         }
 348
 349         while (1) {
 350                 while (!isblank(*s) && *s != '\n')
 351                         s++;
 352
 353                 if (*s == '\n')
 354                         return cmd;
 355
 356                 while (isblank(*s))
 357                         s++;
 358
 359                 *n += 1;
 360         }
 361 }
 362
 363 #endif                          /* DEBUG */
 364
 365 void x86emu_dump_regs(void)
 366 {
 367         printk("\tAX=%04x  ", M.x86.R_AX);
 368         printk("BX=%04x  ", M.x86.R_BX);
 369         printk("CX=%04x  ", M.x86.R_CX);
 370         printk("DX=%04x  ", M.x86.R_DX);
 371         printk("SP=%04x  ", M.x86.R_SP);
 372         printk("BP=%04x  ", M.x86.R_BP);
 373         printk("SI=%04x  ", M.x86.R_SI);
 374         printk("DI=%04x\n", M.x86.R_DI);
 375         printk("\tDS=%04x  ", M.x86.R_DS);
 376         printk("ES=%04x  ", M.x86.R_ES);
 377         printk("SS=%04x  ", M.x86.R_SS);
 378         printk("CS=%04x  ", M.x86.R_CS);
 379         printk("IP=%04x   ", M.x86.R_IP);
 380         if (ACCESS_FLAG(F_OF))
 381                 printk("OV ");  /* CHECKED... */
 382         else
 383                 printk("NV ");
 384         if (ACCESS_FLAG(F_DF))
 385                 printk("DN ");
 386         else
 387                 printk("UP ");
 388         if (ACCESS_FLAG(F_IF))
 389                 printk("EI ");
 390         else
 391                 printk("DI ");
 392         if (ACCESS_FLAG(F_SF))
 393                 printk("NG ");
 394         else
 395                 printk("PL ");
 396         if (ACCESS_FLAG(F_ZF))
 397                 printk("ZR ");
 398         else
 399                 printk("NZ ");
 400         if (ACCESS_FLAG(F_AF))
 401                 printk("AC ");
 402         else
 403                 printk("NA ");
 404         if (ACCESS_FLAG(F_PF))
 405                 printk("PE ");
 406         else
 407                 printk("PO ");
 408         if (ACCESS_FLAG(F_CF))
 409                 printk("CY ");
 410         else
 411                 printk("NC ");
 412         printk("\n");
 413 }
 414
 415 void x86emu_dump_xregs(void)
 416 {
 417         printk("\tEAX=%08x  ", M.x86.R_EAX);
 418         printk("EBX=%08x  ", M.x86.R_EBX);
 419         printk("ECX=%08x  ", M.x86.R_ECX);
 420         printk("EDX=%08x  \n", M.x86.R_EDX);
 421         printk("\tESP=%08x  ", M.x86.R_ESP);
 422         printk("EBP=%08x  ", M.x86.R_EBP);
 423         printk("ESI=%08x  ", M.x86.R_ESI);
 424         printk("EDI=%08x\n", M.x86.R_EDI);
 425         printk("\tDS=%04x  ", M.x86.R_DS);
 426         printk("ES=%04x  ", M.x86.R_ES);
 427         printk("SS=%04x  ", M.x86.R_SS);
 428         printk("CS=%04x  ", M.x86.R_CS);
 429         printk("EIP=%08x\n\t", M.x86.R_EIP);
 430         if (ACCESS_FLAG(F_OF))
 431                 printk("OV ");  /* CHECKED... */
 432         else
 433                 printk("NV ");
 434         if (ACCESS_FLAG(F_DF))
 435                 printk("DN ");
 436         else
 437                 printk("UP ");
 438         if (ACCESS_FLAG(F_IF))
 439                 printk("EI ");
 440         else
 441                 printk("DI ");
 442         if (ACCESS_FLAG(F_SF))
 443                 printk("NG ");
 444         else
 445                 printk("PL ");
 446         if (ACCESS_FLAG(F_ZF))
 447                 printk("ZR ");
 448         else
 449                 printk("NZ ");
 450         if (ACCESS_FLAG(F_AF))
 451                 printk("AC ");
 452         else
 453                 printk("NA ");
 454         if (ACCESS_FLAG(F_PF))
 455                 printk("PE ");
 456         else
 457                 printk("PO ");
 458         if (ACCESS_FLAG(F_CF))
 459                 printk("CY ");
 460         else
 461                 printk("NC ");
 462         printk("\n");
 463 }