| 1 | /**************************************************************************** |
| 2 | |
| 3 | THIS SOFTWARE IS NOT COPYRIGHTED |
| 4 | |
| 5 | HP offers the following for use in the public domain. HP makes no |
| 6 | warranty with regard to the software or it's performance and the |
| 7 | user accepts the software "AS IS" with all faults. |
| 8 | |
| 9 | HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD |
| 10 | TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES |
| 11 | OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| 12 | |
| 13 | ****************************************************************************/ |
| 14 | |
| 15 | /**************************************************************************** |
| 16 | * Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $ |
| 17 | * |
| 18 | * Module name: remcom.c $ |
| 19 | * Revision: 1.34 $ |
| 20 | * Date: 91/03/09 12:29:49 $ |
| 21 | * Contributor: Lake Stevens Instrument Division$ |
| 22 | * |
| 23 | * Description: low level support for gdb debugger. $ |
| 24 | * |
| 25 | * Considerations: only works on target hardware $ |
| 26 | * |
| 27 | * Written by: Glenn Engel $ |
| 28 | * ModuleState: Experimental $ |
| 29 | * |
| 30 | * NOTES: See Below $ |
| 31 | * |
| 32 | * Modified for 386 by Jim Kingdon, Cygnus Support. |
| 33 | * |
| 34 | * To enable debugger support, two things need to happen. One, a |
| 35 | * call to set_debug_traps() is necessary in order to allow any breakpoints |
| 36 | * or error conditions to be properly intercepted and reported to gdb. |
| 37 | * Two, a breakpoint needs to be generated to begin communication. This |
| 38 | * is most easily accomplished by a call to breakpoint(). Breakpoint() |
| 39 | * simulates a breakpoint by executing a trap #1. |
| 40 | * |
| 41 | * The external function exceptionHandler() is |
| 42 | * used to attach a specific handler to a specific 386 vector number. |
| 43 | * It should use the same privilege level it runs at. It should |
| 44 | * install it as an interrupt gate so that interrupts are masked |
| 45 | * while the handler runs. |
| 46 | * Also, need to assign exceptionHook and oldExceptionHook. |
| 47 | * |
| 48 | * Because gdb will sometimes write to the stack area to execute function |
| 49 | * calls, this program cannot rely on using the supervisor stack so it |
| 50 | * uses it's own stack area reserved in the int array remcomStack. |
| 51 | * |
| 52 | ************* |
| 53 | * |
| 54 | * The following gdb commands are supported: |
| 55 | * |
| 56 | * command function Return value |
| 57 | * |
| 58 | * g return the value of the CPU registers hex data or ENN |
| 59 | * G set the value of the CPU registers OK or ENN |
| 60 | * |
| 61 | * mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN |
| 62 | * MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN |
| 63 | * |
| 64 | * c Resume at current address SNN ( signal NN) |
| 65 | * cAA..AA Continue at address AA..AA SNN |
| 66 | * |
| 67 | * s Step one instruction SNN |
| 68 | * sAA..AA Step one instruction from AA..AA SNN |
| 69 | * |
| 70 | * k kill |
| 71 | * |
| 72 | * ? What was the last sigval ? SNN (signal NN) |
| 73 | * |
| 74 | * All commands and responses are sent with a packet which includes a |
| 75 | * checksum. A packet consists of |
| 76 | * |
| 77 | * $<packet info>#<checksum>. |
| 78 | * |
| 79 | * where |
| 80 | * <packet info> :: <characters representing the command or response> |
| 81 | * <checksum> :: < two hex digits computed as modulo 256 sum of <packetinfo>> |
| 82 | * |
| 83 | * When a packet is received, it is first acknowledged with either '+' or '-'. |
| 84 | * '+' indicates a successful transfer. '-' indicates a failed transfer. |
| 85 | * |
| 86 | * Example: |
| 87 | * |
| 88 | * Host: Reply: |
| 89 | * $m0,10#2a +$00010203040506070809101112131415#42 |
| 90 | * |
| 91 | ****************************************************************************/ |
| 92 | |
| 93 | #include <stdio.h> |
| 94 | #include <string.h> |
| 95 | |
| 96 | /************************************************************************ |
| 97 | * |
| 98 | * external low-level support routines |
| 99 | */ |
| 100 | typedef void (*ExceptionHook)(int); /* pointer to function with int parm */ |
| 101 | typedef void (*Function)(); /* pointer to a function */ |
| 102 | |
| 103 | extern void putDebugChar(); /* write a single character */ |
| 104 | extern int getDebugChar(); /* read and return a single char */ |
| 105 | |
| 106 | extern Function exceptionHandler(); /* assign an exception handler */ |
| 107 | extern ExceptionHook exceptionHook; /* hook variable for errors/exceptions */ |
| 108 | |
| 109 | /************************************************************************/ |
| 110 | /* BUFMAX defines the maximum number of characters in inbound/outbound buffers*/ |
| 111 | /* at least NUMREGBYTES*2 are needed for register packets */ |
| 112 | #define BUFMAX 400 |
| 113 | |
| 114 | static char initialized; /* boolean flag. != 0 means we've been initialized */ |
| 115 | |
| 116 | int remote_debug; |
| 117 | /* debug > 0 prints ill-formed commands in valid packets & checksum errors */ |
| 118 | |
| 119 | void waitabit(); |
| 120 | |
| 121 | static const char hexchars[]="0123456789abcdef"; |
| 122 | |
| 123 | /* Number of registers. */ |
| 124 | #define NUMREGS 16 |
| 125 | |
| 126 | /* Number of bytes of registers. */ |
| 127 | #define NUMREGBYTES (NUMREGS * 4) |
| 128 | |
| 129 | enum regnames {EAX, ECX, EDX, EBX, ESP, EBP, ESI, EDI, |
| 130 | PC /* also known as eip */, |
| 131 | PS /* also known as eflags */, |
| 132 | CS, SS, DS, ES, FS, GS}; |
| 133 | |
| 134 | /* |
| 135 | * these should not be static cuz they can be used outside this module |
| 136 | */ |
| 137 | int registers[NUMREGS]; |
| 138 | |
| 139 | #define STACKSIZE 10000 |
| 140 | int remcomStack[STACKSIZE/sizeof(int)]; |
| 141 | static int* stackPtr = &remcomStack[STACKSIZE/sizeof(int) - 1]; |
| 142 | |
| 143 | /* |
| 144 | * In many cases, the system will want to continue exception processing |
| 145 | * when a continue command is given. |
| 146 | * oldExceptionHook is a function to invoke in this case. |
| 147 | */ |
| 148 | |
| 149 | static ExceptionHook oldExceptionHook; |
| 150 | |
| 151 | /*************************** ASSEMBLY CODE MACROS *************************/ |
| 152 | /* */ |
| 153 | |
| 154 | extern void |
| 155 | return_to_prog (); |
| 156 | |
| 157 | /* Restore the program's registers (including the stack pointer, which |
| 158 | means we get the right stack and don't have to worry about popping our |
| 159 | return address and any stack frames and so on) and return. */ |
| 160 | asm(".text"); |
| 161 | asm(".globl _return_to_prog"); |
| 162 | asm("_return_to_prog:"); |
| 163 | asm(" movw _registers+44, %ss"); |
| 164 | asm(" movl _registers+16, %esp"); |
| 165 | asm(" movl _registers+4, %ecx"); |
| 166 | asm(" movl _registers+8, %edx"); |
| 167 | asm(" movl _registers+12, %ebx"); |
| 168 | asm(" movl _registers+20, %ebp"); |
| 169 | asm(" movl _registers+24, %esi"); |
| 170 | asm(" movl _registers+28, %edi"); |
| 171 | asm(" movw _registers+48, %ds"); |
| 172 | asm(" movw _registers+52, %es"); |
| 173 | asm(" movw _registers+56, %fs"); |
| 174 | asm(" movw _registers+60, %gs"); |
| 175 | asm(" movl _registers+36, %eax"); |
| 176 | asm(" pushl %eax"); /* saved eflags */ |
| 177 | asm(" movl _registers+40, %eax"); |
| 178 | asm(" pushl %eax"); /* saved cs */ |
| 179 | asm(" movl _registers+32, %eax"); |
| 180 | asm(" pushl %eax"); /* saved eip */ |
| 181 | asm(" movl _registers, %eax"); |
| 182 | /* use iret to restore pc and flags together so |
| 183 | that trace flag works right. */ |
| 184 | asm(" iret"); |
| 185 | |
| 186 | #define BREAKPOINT() asm(" int $3"); |
| 187 | |
| 188 | /* Put the error code here just in case the user cares. */ |
| 189 | int gdb_i386errcode; |
| 190 | /* Likewise, the vector number here (since GDB only gets the signal |
| 191 | number through the usual means, and that's not very specific). */ |
| 192 | int gdb_i386vector = -1; |
| 193 | |
| 194 | /* GDB stores segment registers in 32-bit words (that's just the way |
| 195 | m-i386v.h is written). So zero the appropriate areas in registers. */ |
| 196 | #define SAVE_REGISTERS1() \ |
| 197 | asm ("movl %eax, _registers"); \ |
| 198 | asm ("movl %ecx, _registers+4"); \ |
| 199 | asm ("movl %edx, _registers+8"); \ |
| 200 | asm ("movl %ebx, _registers+12"); \ |
| 201 | asm ("movl %ebp, _registers+20"); \ |
| 202 | asm ("movl %esi, _registers+24"); \ |
| 203 | asm ("movl %edi, _registers+28"); \ |
| 204 | asm ("movw $0, %ax"); \ |
| 205 | asm ("movw %ds, _registers+48"); \ |
| 206 | asm ("movw %ax, _registers+50"); \ |
| 207 | asm ("movw %es, _registers+52"); \ |
| 208 | asm ("movw %ax, _registers+54"); \ |
| 209 | asm ("movw %fs, _registers+56"); \ |
| 210 | asm ("movw %ax, _registers+58"); \ |
| 211 | asm ("movw %gs, _registers+60"); \ |
| 212 | asm ("movw %ax, _registers+62"); |
| 213 | #define SAVE_ERRCODE() \ |
| 214 | asm ("popl %ebx"); \ |
| 215 | asm ("movl %ebx, _gdb_i386errcode"); |
| 216 | #define SAVE_REGISTERS2() \ |
| 217 | asm ("popl %ebx"); /* old eip */ \ |
| 218 | asm ("movl %ebx, _registers+32"); \ |
| 219 | asm ("popl %ebx"); /* old cs */ \ |
| 220 | asm ("movl %ebx, _registers+40"); \ |
| 221 | asm ("movw %ax, _registers+42"); \ |
| 222 | asm ("popl %ebx"); /* old eflags */ \ |
| 223 | asm ("movl %ebx, _registers+36"); \ |
| 224 | /* Now that we've done the pops, we can save the stack pointer."); */ \ |
| 225 | asm ("movw %ss, _registers+44"); \ |
| 226 | asm ("movw %ax, _registers+46"); \ |
| 227 | asm ("movl %esp, _registers+16"); |
| 228 | |
| 229 | /* See if mem_fault_routine is set, if so just IRET to that address. */ |
| 230 | #define CHECK_FAULT() \ |
| 231 | asm ("cmpl $0, _mem_fault_routine"); \ |
| 232 | asm ("jne mem_fault"); |
| 233 | |
| 234 | asm (".text"); |
| 235 | asm ("mem_fault:"); |
| 236 | /* OK to clobber temp registers; we're just going to end up in set_mem_err. */ |
| 237 | /* Pop error code from the stack and save it. */ |
| 238 | asm (" popl %eax"); |
| 239 | asm (" movl %eax, _gdb_i386errcode"); |
| 240 | |
| 241 | asm (" popl %eax"); /* eip */ |
| 242 | /* We don't want to return there, we want to return to the function |
| 243 | pointed to by mem_fault_routine instead. */ |
| 244 | asm (" movl _mem_fault_routine, %eax"); |
| 245 | asm (" popl %ecx"); /* cs (low 16 bits; junk in hi 16 bits). */ |
| 246 | asm (" popl %edx"); /* eflags */ |
| 247 | |
| 248 | /* Remove this stack frame; when we do the iret, we will be going to |
| 249 | the start of a function, so we want the stack to look just like it |
| 250 | would after a "call" instruction. */ |
| 251 | asm (" leave"); |
| 252 | |
| 253 | /* Push the stuff that iret wants. */ |
| 254 | asm (" pushl %edx"); /* eflags */ |
| 255 | asm (" pushl %ecx"); /* cs */ |
| 256 | asm (" pushl %eax"); /* eip */ |
| 257 | |
| 258 | /* Zero mem_fault_routine. */ |
| 259 | asm (" movl $0, %eax"); |
| 260 | asm (" movl %eax, _mem_fault_routine"); |
| 261 | |
| 262 | asm ("iret"); |
| 263 | |
| 264 | #define CALL_HOOK() asm("call _remcomHandler"); |
| 265 | |
| 266 | /* This function is called when a i386 exception occurs. It saves |
| 267 | * all the cpu regs in the _registers array, munges the stack a bit, |
| 268 | * and invokes an exception handler (remcom_handler). |
| 269 | * |
| 270 | * stack on entry: stack on exit: |
| 271 | * old eflags vector number |
| 272 | * old cs (zero-filled to 32 bits) |
| 273 | * old eip |
| 274 | * |
| 275 | */ |
| 276 | extern void _catchException3(); |
| 277 | asm(".text"); |
| 278 | asm(".globl __catchException3"); |
| 279 | asm("__catchException3:"); |
| 280 | SAVE_REGISTERS1(); |
| 281 | SAVE_REGISTERS2(); |
| 282 | asm ("pushl $3"); |
| 283 | CALL_HOOK(); |
| 284 | |
| 285 | /* Same thing for exception 1. */ |
| 286 | extern void _catchException1(); |
| 287 | asm(".text"); |
| 288 | asm(".globl __catchException1"); |
| 289 | asm("__catchException1:"); |
| 290 | SAVE_REGISTERS1(); |
| 291 | SAVE_REGISTERS2(); |
| 292 | asm ("pushl $1"); |
| 293 | CALL_HOOK(); |
| 294 | |
| 295 | /* Same thing for exception 0. */ |
| 296 | extern void _catchException0(); |
| 297 | asm(".text"); |
| 298 | asm(".globl __catchException0"); |
| 299 | asm("__catchException0:"); |
| 300 | SAVE_REGISTERS1(); |
| 301 | SAVE_REGISTERS2(); |
| 302 | asm ("pushl $0"); |
| 303 | CALL_HOOK(); |
| 304 | |
| 305 | /* Same thing for exception 4. */ |
| 306 | extern void _catchException4(); |
| 307 | asm(".text"); |
| 308 | asm(".globl __catchException4"); |
| 309 | asm("__catchException4:"); |
| 310 | SAVE_REGISTERS1(); |
| 311 | SAVE_REGISTERS2(); |
| 312 | asm ("pushl $4"); |
| 313 | CALL_HOOK(); |
| 314 | |
| 315 | /* Same thing for exception 5. */ |
| 316 | extern void _catchException5(); |
| 317 | asm(".text"); |
| 318 | asm(".globl __catchException5"); |
| 319 | asm("__catchException5:"); |
| 320 | SAVE_REGISTERS1(); |
| 321 | SAVE_REGISTERS2(); |
| 322 | asm ("pushl $5"); |
| 323 | CALL_HOOK(); |
| 324 | |
| 325 | /* Same thing for exception 6. */ |
| 326 | extern void _catchException6(); |
| 327 | asm(".text"); |
| 328 | asm(".globl __catchException6"); |
| 329 | asm("__catchException6:"); |
| 330 | SAVE_REGISTERS1(); |
| 331 | SAVE_REGISTERS2(); |
| 332 | asm ("pushl $6"); |
| 333 | CALL_HOOK(); |
| 334 | |
| 335 | /* Same thing for exception 7. */ |
| 336 | extern void _catchException7(); |
| 337 | asm(".text"); |
| 338 | asm(".globl __catchException7"); |
| 339 | asm("__catchException7:"); |
| 340 | SAVE_REGISTERS1(); |
| 341 | SAVE_REGISTERS2(); |
| 342 | asm ("pushl $7"); |
| 343 | CALL_HOOK(); |
| 344 | |
| 345 | /* Same thing for exception 8. */ |
| 346 | extern void _catchException8(); |
| 347 | asm(".text"); |
| 348 | asm(".globl __catchException8"); |
| 349 | asm("__catchException8:"); |
| 350 | SAVE_REGISTERS1(); |
| 351 | SAVE_ERRCODE(); |
| 352 | SAVE_REGISTERS2(); |
| 353 | asm ("pushl $8"); |
| 354 | CALL_HOOK(); |
| 355 | |
| 356 | /* Same thing for exception 9. */ |
| 357 | extern void _catchException9(); |
| 358 | asm(".text"); |
| 359 | asm(".globl __catchException9"); |
| 360 | asm("__catchException9:"); |
| 361 | SAVE_REGISTERS1(); |
| 362 | SAVE_REGISTERS2(); |
| 363 | asm ("pushl $9"); |
| 364 | CALL_HOOK(); |
| 365 | |
| 366 | /* Same thing for exception 10. */ |
| 367 | extern void _catchException10(); |
| 368 | asm(".text"); |
| 369 | asm(".globl __catchException10"); |
| 370 | asm("__catchException10:"); |
| 371 | SAVE_REGISTERS1(); |
| 372 | SAVE_ERRCODE(); |
| 373 | SAVE_REGISTERS2(); |
| 374 | asm ("pushl $10"); |
| 375 | CALL_HOOK(); |
| 376 | |
| 377 | /* Same thing for exception 12. */ |
| 378 | extern void _catchException12(); |
| 379 | asm(".text"); |
| 380 | asm(".globl __catchException12"); |
| 381 | asm("__catchException12:"); |
| 382 | SAVE_REGISTERS1(); |
| 383 | SAVE_ERRCODE(); |
| 384 | SAVE_REGISTERS2(); |
| 385 | asm ("pushl $12"); |
| 386 | CALL_HOOK(); |
| 387 | |
| 388 | /* Same thing for exception 16. */ |
| 389 | extern void _catchException16(); |
| 390 | asm(".text"); |
| 391 | asm(".globl __catchException16"); |
| 392 | asm("__catchException16:"); |
| 393 | SAVE_REGISTERS1(); |
| 394 | SAVE_REGISTERS2(); |
| 395 | asm ("pushl $16"); |
| 396 | CALL_HOOK(); |
| 397 | |
| 398 | /* For 13, 11, and 14 we have to deal with the CHECK_FAULT stuff. */ |
| 399 | |
| 400 | /* Same thing for exception 13. */ |
| 401 | extern void _catchException13 (); |
| 402 | asm (".text"); |
| 403 | asm (".globl __catchException13"); |
| 404 | asm ("__catchException13:"); |
| 405 | CHECK_FAULT(); |
| 406 | SAVE_REGISTERS1(); |
| 407 | SAVE_ERRCODE(); |
| 408 | SAVE_REGISTERS2(); |
| 409 | asm ("pushl $13"); |
| 410 | CALL_HOOK(); |
| 411 | |
| 412 | /* Same thing for exception 11. */ |
| 413 | extern void _catchException11 (); |
| 414 | asm (".text"); |
| 415 | asm (".globl __catchException11"); |
| 416 | asm ("__catchException11:"); |
| 417 | CHECK_FAULT(); |
| 418 | SAVE_REGISTERS1(); |
| 419 | SAVE_ERRCODE(); |
| 420 | SAVE_REGISTERS2(); |
| 421 | asm ("pushl $11"); |
| 422 | CALL_HOOK(); |
| 423 | |
| 424 | /* Same thing for exception 14. */ |
| 425 | extern void _catchException14 (); |
| 426 | asm (".text"); |
| 427 | asm (".globl __catchException14"); |
| 428 | asm ("__catchException14:"); |
| 429 | CHECK_FAULT(); |
| 430 | SAVE_REGISTERS1(); |
| 431 | SAVE_ERRCODE(); |
| 432 | SAVE_REGISTERS2(); |
| 433 | asm ("pushl $14"); |
| 434 | CALL_HOOK(); |
| 435 | |
| 436 | /* |
| 437 | * remcomHandler is a front end for handle_exception. It moves the |
| 438 | * stack pointer into an area reserved for debugger use. |
| 439 | */ |
| 440 | asm("_remcomHandler:"); |
| 441 | asm(" popl %eax"); /* pop off return address */ |
| 442 | asm(" popl %eax"); /* get the exception number */ |
| 443 | asm(" movl _stackPtr, %esp"); /* move to remcom stack area */ |
| 444 | asm(" pushl %eax"); /* push exception onto stack */ |
| 445 | asm(" call _handle_exception"); /* this never returns */ |
| 446 | |
| 447 | void _returnFromException() |
| 448 | { |
| 449 | return_to_prog (); |
| 450 | } |
| 451 | |
| 452 | int hex(ch) |
| 453 | char ch; |
| 454 | { |
| 455 | if ((ch >= 'a') && (ch <= 'f')) return (ch-'a'+10); |
| 456 | if ((ch >= '0') && (ch <= '9')) return (ch-'0'); |
| 457 | if ((ch >= 'A') && (ch <= 'F')) return (ch-'A'+10); |
| 458 | return (-1); |
| 459 | } |
| 460 | |
| 461 | |
| 462 | /* scan for the sequence $<data>#<checksum> */ |
| 463 | void getpacket(buffer) |
| 464 | char * buffer; |
| 465 | { |
| 466 | unsigned char checksum; |
| 467 | unsigned char xmitcsum; |
| 468 | int i; |
| 469 | int count; |
| 470 | char ch; |
| 471 | |
| 472 | do { |
| 473 | /* wait around for the start character, ignore all other characters */ |
| 474 | while ((ch = (getDebugChar() & 0x7f)) != '$'); |
| 475 | checksum = 0; |
| 476 | xmitcsum = -1; |
| 477 | |
| 478 | count = 0; |
| 479 | |
| 480 | /* now, read until a # or end of buffer is found */ |
| 481 | while (count < BUFMAX) { |
| 482 | ch = getDebugChar() & 0x7f; |
| 483 | if (ch == '#') break; |
| 484 | checksum = checksum + ch; |
| 485 | buffer[count] = ch; |
| 486 | count = count + 1; |
| 487 | } |
| 488 | buffer[count] = 0; |
| 489 | |
| 490 | if (ch == '#') { |
| 491 | xmitcsum = hex(getDebugChar() & 0x7f) << 4; |
| 492 | xmitcsum += hex(getDebugChar() & 0x7f); |
| 493 | if ((remote_debug ) && (checksum != xmitcsum)) { |
| 494 | fprintf (stderr ,"bad checksum. My count = 0x%x, sent=0x%x. buf=%s\n", |
| 495 | checksum,xmitcsum,buffer); |
| 496 | } |
| 497 | |
| 498 | if (checksum != xmitcsum) putDebugChar('-'); /* failed checksum */ |
| 499 | else { |
| 500 | putDebugChar('+'); /* successful transfer */ |
| 501 | /* if a sequence char is present, reply the sequence ID */ |
| 502 | if (buffer[2] == ':') { |
| 503 | putDebugChar( buffer[0] ); |
| 504 | putDebugChar( buffer[1] ); |
| 505 | /* remove sequence chars from buffer */ |
| 506 | count = strlen(buffer); |
| 507 | for (i=3; i <= count; i++) buffer[i-3] = buffer[i]; |
| 508 | } |
| 509 | } |
| 510 | } |
| 511 | } while (checksum != xmitcsum); |
| 512 | |
| 513 | } |
| 514 | |
| 515 | /* send the packet in buffer. */ |
| 516 | |
| 517 | |
| 518 | void putpacket(buffer) |
| 519 | char * buffer; |
| 520 | { |
| 521 | unsigned char checksum; |
| 522 | int count; |
| 523 | char ch; |
| 524 | |
| 525 | /* $<packet info>#<checksum>. */ |
| 526 | do { |
| 527 | putDebugChar('$'); |
| 528 | checksum = 0; |
| 529 | count = 0; |
| 530 | |
| 531 | while (ch=buffer[count]) { |
| 532 | putDebugChar(ch); |
| 533 | checksum += ch; |
| 534 | count += 1; |
| 535 | } |
| 536 | |
| 537 | putDebugChar('#'); |
| 538 | putDebugChar(hexchars[checksum >> 4]); |
| 539 | putDebugChar(hexchars[checksum % 16]); |
| 540 | |
| 541 | } while ((getDebugChar() & 0x7f) != '+'); |
| 542 | |
| 543 | } |
| 544 | |
| 545 | char remcomInBuffer[BUFMAX]; |
| 546 | char remcomOutBuffer[BUFMAX]; |
| 547 | static short error; |
| 548 | |
| 549 | |
| 550 | void debug_error(format, parm) |
| 551 | char * format; |
| 552 | char * parm; |
| 553 | { |
| 554 | if (remote_debug) fprintf (stderr,format,parm); |
| 555 | } |
| 556 | |
| 557 | /* Address of a routine to RTE to if we get a memory fault. */ |
| 558 | static void (*volatile mem_fault_routine)() = NULL; |
| 559 | |
| 560 | /* Indicate to caller of mem2hex or hex2mem that there has been an |
| 561 | error. */ |
| 562 | static volatile int mem_err = 0; |
| 563 | |
| 564 | void |
| 565 | set_mem_err () |
| 566 | { |
| 567 | mem_err = 1; |
| 568 | } |
| 569 | |
| 570 | /* These are separate functions so that they are so short and sweet |
| 571 | that the compiler won't save any registers (if there is a fault |
| 572 | to mem_fault, they won't get restored, so there better not be any |
| 573 | saved). */ |
| 574 | int |
| 575 | get_char (addr) |
| 576 | char *addr; |
| 577 | { |
| 578 | return *addr; |
| 579 | } |
| 580 | |
| 581 | void |
| 582 | set_char (addr, val) |
| 583 | char *addr; |
| 584 | int val; |
| 585 | { |
| 586 | *addr = val; |
| 587 | } |
| 588 | |
| 589 | /* convert the memory pointed to by mem into hex, placing result in buf */ |
| 590 | /* return a pointer to the last char put in buf (null) */ |
| 591 | /* If MAY_FAULT is non-zero, then we should set mem_err in response to |
| 592 | a fault; if zero treat a fault like any other fault in the stub. */ |
| 593 | char* mem2hex(mem, buf, count, may_fault) |
| 594 | char* mem; |
| 595 | char* buf; |
| 596 | int count; |
| 597 | int may_fault; |
| 598 | { |
| 599 | int i; |
| 600 | unsigned char ch; |
| 601 | |
| 602 | if (may_fault) |
| 603 | mem_fault_routine = set_mem_err; |
| 604 | for (i=0;i<count;i++) { |
| 605 | ch = get_char (mem++); |
| 606 | if (may_fault && mem_err) |
| 607 | return (buf); |
| 608 | *buf++ = hexchars[ch >> 4]; |
| 609 | *buf++ = hexchars[ch % 16]; |
| 610 | } |
| 611 | *buf = 0; |
| 612 | if (may_fault) |
| 613 | mem_fault_routine = NULL; |
| 614 | return(buf); |
| 615 | } |
| 616 | |
| 617 | /* convert the hex array pointed to by buf into binary to be placed in mem */ |
| 618 | /* return a pointer to the character AFTER the last byte written */ |
| 619 | char* hex2mem(buf, mem, count, may_fault) |
| 620 | char* buf; |
| 621 | char* mem; |
| 622 | int count; |
| 623 | int may_fault; |
| 624 | { |
| 625 | int i; |
| 626 | unsigned char ch; |
| 627 | |
| 628 | if (may_fault) |
| 629 | mem_fault_routine = set_mem_err; |
| 630 | for (i=0;i<count;i++) { |
| 631 | ch = hex(*buf++) << 4; |
| 632 | ch = ch + hex(*buf++); |
| 633 | set_char (mem++, ch); |
| 634 | if (may_fault && mem_err) |
| 635 | return (mem); |
| 636 | } |
| 637 | if (may_fault) |
| 638 | mem_fault_routine = NULL; |
| 639 | return(mem); |
| 640 | } |
| 641 | |
| 642 | /* this function takes the 386 exception vector and attempts to |
| 643 | translate this number into a unix compatible signal value */ |
| 644 | int computeSignal( exceptionVector ) |
| 645 | int exceptionVector; |
| 646 | { |
| 647 | int sigval; |
| 648 | switch (exceptionVector) { |
| 649 | case 0 : sigval = 8; break; /* divide by zero */ |
| 650 | case 1 : sigval = 5; break; /* debug exception */ |
| 651 | case 3 : sigval = 5; break; /* breakpoint */ |
| 652 | case 4 : sigval = 16; break; /* into instruction (overflow) */ |
| 653 | case 5 : sigval = 16; break; /* bound instruction */ |
| 654 | case 6 : sigval = 4; break; /* Invalid opcode */ |
| 655 | case 7 : sigval = 8; break; /* coprocessor not available */ |
| 656 | case 8 : sigval = 7; break; /* double fault */ |
| 657 | case 9 : sigval = 11; break; /* coprocessor segment overrun */ |
| 658 | case 10 : sigval = 11; break; /* Invalid TSS */ |
| 659 | case 11 : sigval = 11; break; /* Segment not present */ |
| 660 | case 12 : sigval = 11; break; /* stack exception */ |
| 661 | case 13 : sigval = 11; break; /* general protection */ |
| 662 | case 14 : sigval = 11; break; /* page fault */ |
| 663 | case 16 : sigval = 7; break; /* coprocessor error */ |
| 664 | default: |
| 665 | sigval = 7; /* "software generated"*/ |
| 666 | } |
| 667 | return (sigval); |
| 668 | } |
| 669 | |
| 670 | /**********************************************/ |
| 671 | /* WHILE WE FIND NICE HEX CHARS, BUILD AN INT */ |
| 672 | /* RETURN NUMBER OF CHARS PROCESSED */ |
| 673 | /**********************************************/ |
| 674 | int hexToInt(char **ptr, int *intValue) |
| 675 | { |
| 676 | int numChars = 0; |
| 677 | int hexValue; |
| 678 | |
| 679 | *intValue = 0; |
| 680 | |
| 681 | while (**ptr) |
| 682 | { |
| 683 | hexValue = hex(**ptr); |
| 684 | if (hexValue >=0) |
| 685 | { |
| 686 | *intValue = (*intValue <<4) | hexValue; |
| 687 | numChars ++; |
| 688 | } |
| 689 | else |
| 690 | break; |
| 691 | |
| 692 | (*ptr)++; |
| 693 | } |
| 694 | |
| 695 | return (numChars); |
| 696 | } |
| 697 | |
| 698 | /* |
| 699 | * This function does all command procesing for interfacing to gdb. |
| 700 | */ |
| 701 | void handle_exception(int exceptionVector) |
| 702 | { |
| 703 | int sigval; |
| 704 | int addr, length; |
| 705 | char * ptr; |
| 706 | int newPC; |
| 707 | |
| 708 | gdb_i386vector = exceptionVector; |
| 709 | |
| 710 | if (remote_debug) printf("vector=%d, sr=0x%x, pc=0x%x\n", |
| 711 | exceptionVector, |
| 712 | registers[ PS ], |
| 713 | registers[ PC ]); |
| 714 | |
| 715 | /* reply to host that an exception has occurred */ |
| 716 | sigval = computeSignal( exceptionVector ); |
| 717 | remcomOutBuffer[0] = 'S'; |
| 718 | remcomOutBuffer[1] = hexchars[sigval >> 4]; |
| 719 | remcomOutBuffer[2] = hexchars[sigval % 16]; |
| 720 | remcomOutBuffer[3] = 0; |
| 721 | |
| 722 | putpacket(remcomOutBuffer); |
| 723 | |
| 724 | while (1==1) { |
| 725 | error = 0; |
| 726 | remcomOutBuffer[0] = 0; |
| 727 | getpacket(remcomInBuffer); |
| 728 | switch (remcomInBuffer[0]) { |
| 729 | case '?' : remcomOutBuffer[0] = 'S'; |
| 730 | remcomOutBuffer[1] = hexchars[sigval >> 4]; |
| 731 | remcomOutBuffer[2] = hexchars[sigval % 16]; |
| 732 | remcomOutBuffer[3] = 0; |
| 733 | break; |
| 734 | case 'd' : remote_debug = !(remote_debug); /* toggle debug flag */ |
| 735 | break; |
| 736 | case 'g' : /* return the value of the CPU registers */ |
| 737 | mem2hex((char*) registers, remcomOutBuffer, NUMREGBYTES, 0); |
| 738 | break; |
| 739 | case 'G' : /* set the value of the CPU registers - return OK */ |
| 740 | hex2mem(&remcomInBuffer[1], (char*) registers, NUMREGBYTES, 0); |
| 741 | strcpy(remcomOutBuffer,"OK"); |
| 742 | break; |
| 743 | case 'P' : /* set the value of a single CPU register - return OK */ |
| 744 | { |
| 745 | int regno; |
| 746 | |
| 747 | ptr = &remcomInBuffer[1]; |
| 748 | if (hexToInt (&ptr, ®no) && *ptr++ == '=') |
| 749 | if (regno >= 0 && regno < NUMREGS) |
| 750 | { |
| 751 | hex2mem (ptr, (char *)®isters[regno], 4, 0); |
| 752 | strcpy(remcomOutBuffer,"OK"); |
| 753 | break; |
| 754 | } |
| 755 | |
| 756 | strcpy (remcomOutBuffer, "E01"); |
| 757 | break; |
| 758 | } |
| 759 | |
| 760 | /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ |
| 761 | case 'm' : |
| 762 | /* TRY TO READ %x,%x. IF SUCCEED, SET PTR = 0 */ |
| 763 | ptr = &remcomInBuffer[1]; |
| 764 | if (hexToInt(&ptr,&addr)) |
| 765 | if (*(ptr++) == ',') |
| 766 | if (hexToInt(&ptr,&length)) |
| 767 | { |
| 768 | ptr = 0; |
| 769 | mem_err = 0; |
| 770 | mem2hex((char*) addr, remcomOutBuffer, length, 1); |
| 771 | if (mem_err) { |
| 772 | strcpy (remcomOutBuffer, "E03"); |
| 773 | debug_error ("memory fault"); |
| 774 | } |
| 775 | } |
| 776 | |
| 777 | if (ptr) |
| 778 | { |
| 779 | strcpy(remcomOutBuffer,"E01"); |
| 780 | debug_error("malformed read memory command: %s",remcomInBuffer); |
| 781 | } |
| 782 | break; |
| 783 | |
| 784 | /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */ |
| 785 | case 'M' : |
| 786 | /* TRY TO READ '%x,%x:'. IF SUCCEED, SET PTR = 0 */ |
| 787 | ptr = &remcomInBuffer[1]; |
| 788 | if (hexToInt(&ptr,&addr)) |
| 789 | if (*(ptr++) == ',') |
| 790 | if (hexToInt(&ptr,&length)) |
| 791 | if (*(ptr++) == ':') |
| 792 | { |
| 793 | mem_err = 0; |
| 794 | hex2mem(ptr, (char*) addr, length, 1); |
| 795 | |
| 796 | if (mem_err) { |
| 797 | strcpy (remcomOutBuffer, "E03"); |
| 798 | debug_error ("memory fault"); |
| 799 | } else { |
| 800 | strcpy(remcomOutBuffer,"OK"); |
| 801 | } |
| 802 | |
| 803 | ptr = 0; |
| 804 | } |
| 805 | if (ptr) |
| 806 | { |
| 807 | strcpy(remcomOutBuffer,"E02"); |
| 808 | debug_error("malformed write memory command: %s",remcomInBuffer); |
| 809 | } |
| 810 | break; |
| 811 | |
| 812 | /* cAA..AA Continue at address AA..AA(optional) */ |
| 813 | /* sAA..AA Step one instruction from AA..AA(optional) */ |
| 814 | case 'c' : |
| 815 | case 's' : |
| 816 | /* try to read optional parameter, pc unchanged if no parm */ |
| 817 | ptr = &remcomInBuffer[1]; |
| 818 | if (hexToInt(&ptr,&addr)) |
| 819 | registers[ PC ] = addr; |
| 820 | |
| 821 | newPC = registers[ PC]; |
| 822 | |
| 823 | /* clear the trace bit */ |
| 824 | registers[ PS ] &= 0xfffffeff; |
| 825 | |
| 826 | /* set the trace bit if we're stepping */ |
| 827 | if (remcomInBuffer[0] == 's') registers[ PS ] |= 0x100; |
| 828 | |
| 829 | /* |
| 830 | * If we found a match for the PC AND we are not returning |
| 831 | * as a result of a breakpoint (33), |
| 832 | * trace exception (9), nmi (31), jmp to |
| 833 | * the old exception handler as if this code never ran. |
| 834 | */ |
| 835 | #if 0 |
| 836 | /* Don't really think we need this, except maybe for protection |
| 837 | exceptions. */ |
| 838 | /* |
| 839 | * invoke the previous handler. |
| 840 | */ |
| 841 | if (oldExceptionHook) |
| 842 | (*oldExceptionHook) (frame->exceptionVector); |
| 843 | newPC = registers[ PC ]; /* pc may have changed */ |
| 844 | #endif /* 0 */ |
| 845 | |
| 846 | _returnFromException(); /* this is a jump */ |
| 847 | |
| 848 | break; |
| 849 | |
| 850 | /* kill the program */ |
| 851 | case 'k' : /* do nothing */ |
| 852 | #if 0 |
| 853 | /* Huh? This doesn't look like "nothing". |
| 854 | m68k-stub.c and sparc-stub.c don't have it. */ |
| 855 | BREAKPOINT(); |
| 856 | #endif |
| 857 | break; |
| 858 | } /* switch */ |
| 859 | |
| 860 | /* reply to the request */ |
| 861 | putpacket(remcomOutBuffer); |
| 862 | } |
| 863 | } |
| 864 | |
| 865 | /* this function is used to set up exception handlers for tracing and |
| 866 | breakpoints */ |
| 867 | void set_debug_traps() |
| 868 | { |
| 869 | extern void remcomHandler(); |
| 870 | int exception; |
| 871 | |
| 872 | stackPtr = &remcomStack[STACKSIZE/sizeof(int) - 1]; |
| 873 | |
| 874 | exceptionHandler (0, _catchException0); |
| 875 | exceptionHandler (1, _catchException1); |
| 876 | exceptionHandler (3, _catchException3); |
| 877 | exceptionHandler (4, _catchException4); |
| 878 | exceptionHandler (5, _catchException5); |
| 879 | exceptionHandler (6, _catchException6); |
| 880 | exceptionHandler (7, _catchException7); |
| 881 | exceptionHandler (8, _catchException8); |
| 882 | exceptionHandler (9, _catchException9); |
| 883 | exceptionHandler (10, _catchException10); |
| 884 | exceptionHandler (11, _catchException11); |
| 885 | exceptionHandler (12, _catchException12); |
| 886 | exceptionHandler (13, _catchException13); |
| 887 | exceptionHandler (14, _catchException14); |
| 888 | exceptionHandler (16, _catchException16); |
| 889 | |
| 890 | if (exceptionHook != remcomHandler) |
| 891 | { |
| 892 | oldExceptionHook = exceptionHook; |
| 893 | exceptionHook = remcomHandler; |
| 894 | } |
| 895 | |
| 896 | /* In case GDB is started before us, ack any packets (presumably |
| 897 | "$?#xx") sitting there. */ |
| 898 | putDebugChar ('+'); |
| 899 | |
| 900 | initialized = 1; |
| 901 | |
| 902 | } |
| 903 | |
| 904 | /* This function will generate a breakpoint exception. It is used at the |
| 905 | beginning of a program to sync up with a debugger and can be used |
| 906 | otherwise as a quick means to stop program execution and "break" into |
| 907 | the debugger. */ |
| 908 | |
| 909 | void breakpoint() |
| 910 | { |
| 911 | if (initialized) |
| 912 | #if 0 |
| 913 | handle_exception(3); |
| 914 | #else |
| 915 | BREAKPOINT(); |
| 916 | #endif |
| 917 | waitabit(); |
| 918 | } |
| 919 | |
| 920 | int waitlimit = 1000000; |
| 921 | |
| 922 | void |
| 923 | waitabit() |
| 924 | { |
| 925 | int i; |
| 926 | for (i = 0; i < waitlimit; i++) ; |
| 927 | } |