arch/mn10300/kernel/gdb-stub.c

   1 /* MN10300 GDB stub
   2  *
   3  * Originally written by Glenn Engel, Lake Stevens Instrument Division
   4  *
   5  * Contributed by HP Systems
   6  *
   7  * Modified for SPARC by Stu Grossman, Cygnus Support.
   8  *
   9  * Modified for Linux/MIPS (and MIPS in general) by Andreas Busse
  10  * Send complaints, suggestions etc. to <andy@waldorf-gmbh.de>
  11  *
  12  * Copyright (C) 1995 Andreas Busse
  13  *
  14  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
  15  * Modified for Linux/mn10300 by David Howells <dhowells@redhat.com>
  16  */
  17
  18 /*
  19  *  To enable debugger support, two things need to happen.  One, a
  20  *  call to set_debug_traps() is necessary in order to allow any breakpoints
  21  *  or error conditions to be properly intercepted and reported to gdb.
  22  *  Two, a breakpoint needs to be generated to begin communication.  This
  23  *  is most easily accomplished by a call to breakpoint().  Breakpoint()
  24  *  simulates a breakpoint by executing a BREAK instruction.
  25  *
  26  *
  27  *    The following gdb commands are supported:
  28  *
  29  * command          function                               Return value
  30  *
  31  *    g             return the value of the CPU registers  hex data or ENN
  32  *    G             set the value of the CPU registers     OK or ENN
  33  *
  34  *    mAA..AA,LLLL  Read LLLL bytes at address AA..AA      hex data or ENN
  35  *    MAA..AA,LLLL: Write LLLL bytes at address AA.AA      OK or ENN
  36  *
  37  *    c             Resume at current address              SNN   ( signal NN)
  38  *    cAA..AA       Continue at address AA..AA             SNN
  39  *
  40  *    s             Step one instruction                   SNN
  41  *    sAA..AA       Step one instruction from AA..AA       SNN
  42  *
  43  *    k             kill
  44  *
  45  *    ?             What was the last sigval ?             SNN   (signal NN)
  46  *
  47  *    bBB..BB       Set baud rate to BB..BB                OK or BNN, then sets
  48  *                                                         baud rate
  49  *
  50  * All commands and responses are sent with a packet which includes a
  51  * checksum.  A packet consists of
  52  *
  53  * $<packet info>#<checksum>.
  54  *
  55  * where
  56  * <packet info> :: <characters representing the command or response>
  57  * <checksum>    :: < two hex digits computed as modulo 256 sum of <packetinfo>>
  58  *
  59  * When a packet is received, it is first acknowledged with either '+' or '-'.
  60  * '+' indicates a successful transfer.  '-' indicates a failed transfer.
  61  *
  62  * Example:
  63  *
  64  * Host:                  Reply:
  65  * $m0,10#2a               +$00010203040506070809101112131415#42
  66  *
  67  *
  68  *  ==============
  69  *  MORE EXAMPLES:
  70  *  ==============
  71  *
  72  *  For reference -- the following are the steps that one
  73  *  company took (RidgeRun Inc) to get remote gdb debugging
  74  *  going. In this scenario the host machine was a PC and the
  75  *  target platform was a Galileo EVB64120A MIPS evaluation
  76  *  board.
  77  *
  78  *  Step 1:
  79  *  First download gdb-5.0.tar.gz from the internet.
  80  *  and then build/install the package.
  81  *
  82  *  Example:
  83  *    $ tar zxf gdb-5.0.tar.gz
  84  *    $ cd gdb-5.0
  85  *    $ ./configure --target=am33_2.0-linux-gnu
  86  *    $ make
  87  *    $ install
  88  *    am33_2.0-linux-gnu-gdb
  89  *
  90  *  Step 2:
  91  *  Configure linux for remote debugging and build it.
  92  *
  93  *  Example:
  94  *    $ cd ~/linux
  95  *    $ make menuconfig <go to "Kernel Hacking" and turn on remote debugging>
  96  *    $ make dep; make vmlinux
  97  *
  98  *  Step 3:
  99  *  Download the kernel to the remote target and start
 100  *  the kernel running. It will promptly halt and wait
 101  *  for the host gdb session to connect. It does this
 102  *  since the "Kernel Hacking" option has defined
 103  *  CONFIG_REMOTE_DEBUG which in turn enables your calls
 104  *  to:
 105  *     set_debug_traps();
 106  *     breakpoint();
 107  *
 108  *  Step 4:
 109  *  Start the gdb session on the host.
 110  *
 111  *  Example:
 112  *    $ am33_2.0-linux-gnu-gdb vmlinux
 113  *    (gdb) set remotebaud 115200
 114  *    (gdb) target remote /dev/ttyS1
 115  *    ...at this point you are connected to
 116  *       the remote target and can use gdb
 117  *       in the normal fasion. Setting
 118  *       breakpoints, single stepping,
 119  *       printing variables, etc.
 120  *
 121  */
 122
 123 #include <linux/string.h>
 124 #include <linux/kernel.h>
 125 #include <linux/signal.h>
 126 #include <linux/sched.h>
 127 #include <linux/mm.h>
 128 #include <linux/console.h>
 129 #include <linux/init.h>
 130 #include <linux/bug.h>
 131
 132 #include <asm/pgtable.h>
 133 #include <asm/system.h>
 134 #include <asm/gdb-stub.h>
 135 #include <asm/exceptions.h>
 136 #include <asm/cacheflush.h>
 137 #include <asm/serial-regs.h>
 138 #include <asm/busctl-regs.h>
 139 #include <unit/leds.h>
 140 #include <unit/serial.h>
 141
 142 /* define to use F7F7 rather than FF which is subverted by JTAG debugger */
 143 #undef GDBSTUB_USE_F7F7_AS_BREAKPOINT
 144
 145 /*
 146  * BUFMAX defines the maximum number of characters in inbound/outbound buffers
 147  * at least NUMREGBYTES*2 are needed for register packets
 148  */
 149 #define BUFMAX 2048
 150
 151 static const char gdbstub_banner[] =
 152         "Linux/MN10300 GDB Stub (c) RedHat 2007\n";
 153
 154 u8      gdbstub_rx_buffer[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
 155 u32     gdbstub_rx_inp;
 156 u32     gdbstub_rx_outp;
 157 u8      gdbstub_busy;
 158 u8      gdbstub_rx_overflow;
 159 u8      gdbstub_rx_unget;
 160
 161 static u8       gdbstub_flush_caches;
 162 static char     input_buffer[BUFMAX];
 163 static char     output_buffer[BUFMAX];
 164 static char     trans_buffer[BUFMAX];
 165
 166 struct gdbstub_bkpt {
 167         u8      *addr;          /* address of breakpoint */
 168         u8      len;            /* size of breakpoint */
 169         u8      origbytes[7];   /* original bytes */
 170 };
 171
 172 static struct gdbstub_bkpt gdbstub_bkpts[256];
 173
 174 /*
 175  * local prototypes
 176  */
 177 static void getpacket(char *buffer);
 178 static int putpacket(char *buffer);
 179 static int computeSignal(enum exception_code excep);
 180 static int hex(unsigned char ch);
 181 static int hexToInt(char **ptr, int *intValue);
 182 static unsigned char *mem2hex(const void *mem, char *buf, int count,
 183                               int may_fault);
 184 static const char *hex2mem(const char *buf, void *_mem, int count,
 185                            int may_fault);
 186
 187 /*
 188  * Convert ch from a hex digit to an int
 189  */
 190 static int hex(unsigned char ch)
 191 {
 192         if (ch >= 'a' && ch <= 'f')
 193                 return ch - 'a' + 10;
 194         if (ch >= '0' && ch <= '9')
 195                 return ch - '0';
 196         if (ch >= 'A' && ch <= 'F')
 197                 return ch - 'A' + 10;
 198         return -1;
 199 }
 200
 201 #ifdef CONFIG_GDBSTUB_DEBUGGING
 202
 203 void debug_to_serial(const char *p, int n)
 204 {
 205         __debug_to_serial(p, n);
 206         /* gdbstub_console_write(NULL, p, n); */
 207 }
 208
 209 void gdbstub_printk(const char *fmt, ...)
 210 {
 211         va_list args;
 212         int len;
 213
 214         /* Emit the output into the temporary buffer */
 215         va_start(args, fmt);
 216         len = vsnprintf(trans_buffer, sizeof(trans_buffer), fmt, args);
 217         va_end(args);
 218         debug_to_serial(trans_buffer, len);
 219 }
 220
 221 #endif
 222
 223 static inline char *gdbstub_strcpy(char *dst, const char *src)
 224 {
 225         int loop = 0;
 226         while ((dst[loop] = src[loop]))
 227                loop++;
 228         return dst;
 229 }
 230
 231 /*
 232  * scan for the sequence $<data>#<checksum>
 233  */
 234 static void getpacket(char *buffer)
 235 {
 236         unsigned char checksum;
 237         unsigned char xmitcsum;
 238         unsigned char ch;
 239         int count, i, ret, error;
 240
 241         for (;;) {
 242                 /*
 243                  * wait around for the start character,
 244                  * ignore all other characters
 245                  */
 246                 do {
 247                         gdbstub_io_rx_char(&ch, 0);
 248                 } while (ch != '$');
 249
 250                 checksum = 0;
 251                 xmitcsum = -1;
 252                 count = 0;
 253                 error = 0;
 254
 255                 /*
 256                  * now, read until a # or end of buffer is found
 257                  */
 258                 while (count < BUFMAX) {
 259                         ret = gdbstub_io_rx_char(&ch, 0);
 260                         if (ret < 0)
 261                                 error = ret;
 262
 263                         if (ch == '#')
 264                                 break;
 265                         checksum += ch;
 266                         buffer[count] = ch;
 267                         count++;
 268                 }
 269
 270                 if (error == -EIO) {
 271                         gdbstub_proto("### GDB Rx Error - Skipping packet"
 272                                       " ###\n");
 273                         gdbstub_proto("### GDB Tx NAK\n");
 274                         gdbstub_io_tx_char('-');
 275                         continue;
 276                 }
 277
 278                 if (count >= BUFMAX || error)
 279                         continue;
 280
 281                 buffer[count] = 0;
 282
 283                 /* read the checksum */
 284                 ret = gdbstub_io_rx_char(&ch, 0);
 285                 if (ret < 0)
 286                         error = ret;
 287                 xmitcsum = hex(ch) << 4;
 288
 289                 ret = gdbstub_io_rx_char(&ch, 0);
 290                 if (ret < 0)
 291                         error = ret;
 292                 xmitcsum |= hex(ch);
 293
 294                 if (error) {
 295                         if (error == -EIO)
 296                                 gdbstub_io("### GDB Rx Error -"
 297                                            " Skipping packet\n");
 298                         gdbstub_io("### GDB Tx NAK\n");
 299                         gdbstub_io_tx_char('-');
 300                         continue;
 301                 }
 302
 303                 /* check the checksum */
 304                 if (checksum != xmitcsum) {
 305                         gdbstub_io("### GDB Tx NAK\n");
 306                         gdbstub_io_tx_char('-');        /* failed checksum */
 307                         continue;
 308                 }
 309
 310                 gdbstub_proto("### GDB Rx '$%s#%02x' ###\n", buffer, checksum);
 311                 gdbstub_io("### GDB Tx ACK\n");
 312                 gdbstub_io_tx_char('+'); /* successful transfer */
 313
 314                 /*
 315                  * if a sequence char is present,
 316                  * reply the sequence ID
 317                  */
 318                 if (buffer[2] == ':') {
 319                         gdbstub_io_tx_char(buffer[0]);
 320                         gdbstub_io_tx_char(buffer[1]);
 321
 322                         /*
 323                          * remove sequence chars from buffer
 324                          */
 325                         count = 0;
 326                         while (buffer[count])
 327                                 count++;
 328                         for (i = 3; i <= count; i++)
 329                                 buffer[i - 3] = buffer[i];
 330                 }
 331
 332                 break;
 333         }
 334 }
 335
 336 /*
 337  * send the packet in buffer.
 338  * - return 0 if successfully ACK'd
 339  * - return 1 if abandoned due to new incoming packet
 340  */
 341 static int putpacket(char *buffer)
 342 {
 343         unsigned char checksum;
 344         unsigned char ch;
 345         int count;
 346
 347         /*
 348          * $<packet info>#<checksum>.
 349          */
 350         gdbstub_proto("### GDB Tx $'%s'#?? ###\n", buffer);
 351
 352         do {
 353                 gdbstub_io_tx_char('$');
 354                 checksum = 0;
 355                 count = 0;
 356
 357                 while ((ch = buffer[count]) != 0) {
 358                         gdbstub_io_tx_char(ch);
 359                         checksum += ch;
 360                         count += 1;
 361                 }
 362
 363                 gdbstub_io_tx_char('#');
 364                 gdbstub_io_tx_char(hex_asc_hi(checksum));
 365                 gdbstub_io_tx_char(hex_asc_lo(checksum));
 366
 367         } while (gdbstub_io_rx_char(&ch, 0),
 368                  ch == '-' && (gdbstub_io("### GDB Rx NAK\n"), 0),
 369                  ch != '-' && ch != '+' &&
 370                  (gdbstub_io("### GDB Rx ??? %02x\n", ch), 0),
 371                  ch != '+' && ch != '$');
 372
 373         if (ch == '+') {
 374                 gdbstub_io("### GDB Rx ACK\n");
 375                 return 0;
 376         }
 377
 378         gdbstub_io("### GDB Tx Abandoned\n");
 379         gdbstub_rx_unget = ch;
 380         return 1;
 381 }
 382
 383 /*
 384  * While we find nice hex chars, build an int.
 385  * Return number of chars processed.
 386  */
 387 static int hexToInt(char **ptr, int *intValue)
 388 {
 389         int numChars = 0;
 390         int hexValue;
 391
 392         *intValue = 0;
 393
 394         while (**ptr) {
 395                 hexValue = hex(**ptr);
 396                 if (hexValue < 0)
 397                         break;
 398
 399                 *intValue = (*intValue << 4) | hexValue;
 400                 numChars++;
 401
 402                 (*ptr)++;
 403         }
 404
 405         return (numChars);
 406 }
 407
 408 /*
 409  * We single-step by setting breakpoints. When an exception
 410  * is handled, we need to restore the instructions hoisted
 411  * when the breakpoints were set.
 412  *
 413  * This is where we save the original instructions.
 414  */
 415 static struct gdb_bp_save {
 416         u8      *addr;
 417         u8      opcode[2];
 418 } step_bp[2];
 419
 420 static const unsigned char gdbstub_insn_sizes[256] =
 421 {
 422         /* 1  2  3  4  5  6  7  8  9  a  b  c  d  e  f */
 423         1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, /* 0 */
 424         1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 1 */
 425         2, 2, 2, 2, 3, 3, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, /* 2 */
 426         3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, /* 3 */
 427         1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, /* 4 */
 428         1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, /* 5 */
 429         1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 6 */
 430         1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 7 */
 431         2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 8 */
 432         2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 9 */
 433         2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* a */
 434         2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* b */
 435         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 2, /* c */
 436         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* d */
 437         1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* e */
 438         0, 2, 2, 2, 2, 2, 2, 4, 0, 3, 0, 4, 0, 6, 7, 1  /* f */
 439 };
 440
 441 static int __gdbstub_mark_bp(u8 *addr, int ix)
 442 {
 443         /* vmalloc area */
 444         if (((u8 *) VMALLOC_START <= addr) && (addr < (u8 *) VMALLOC_END))
 445                 goto okay;
 446         /* SRAM, SDRAM */
 447         if (((u8 *) 0x80000000UL <= addr) && (addr < (u8 *) 0xa0000000UL))
 448                 goto okay;
 449         return 0;
 450
 451 okay:
 452         if (gdbstub_read_byte(addr + 0, &step_bp[ix].opcode[0]) < 0 ||
 453             gdbstub_read_byte(addr + 1, &step_bp[ix].opcode[1]) < 0)
 454                 return 0;
 455
 456         step_bp[ix].addr = addr;
 457         return 1;
 458 }
 459
 460 static inline void __gdbstub_restore_bp(void)
 461 {
 462 #ifdef GDBSTUB_USE_F7F7_AS_BREAKPOINT
 463         if (step_bp[0].addr) {
 464                 gdbstub_write_byte(step_bp[0].opcode[0], step_bp[0].addr + 0);
 465                 gdbstub_write_byte(step_bp[0].opcode[1], step_bp[0].addr + 1);
 466         }
 467         if (step_bp[1].addr) {
 468                 gdbstub_write_byte(step_bp[1].opcode[0], step_bp[1].addr + 0);
 469                 gdbstub_write_byte(step_bp[1].opcode[1], step_bp[1].addr + 1);
 470         }
 471 #else
 472         if (step_bp[0].addr)
 473                 gdbstub_write_byte(step_bp[0].opcode[0], step_bp[0].addr + 0);
 474         if (step_bp[1].addr)
 475                 gdbstub_write_byte(step_bp[1].opcode[0], step_bp[1].addr + 0);
 476 #endif
 477
 478         gdbstub_flush_caches = 1;
 479
 480         step_bp[0].addr         = NULL;
 481         step_bp[0].opcode[0]    = 0;
 482         step_bp[0].opcode[1]    = 0;
 483         step_bp[1].addr         = NULL;
 484         step_bp[1].opcode[0]    = 0;
 485         step_bp[1].opcode[1]    = 0;
 486 }
 487
 488 /*
 489  * emulate single stepping by means of breakpoint instructions
 490  */
 491 static int gdbstub_single_step(struct pt_regs *regs)
 492 {
 493         unsigned size;
 494         uint32_t x;
 495         uint8_t cur, *pc, *sp;
 496
 497         step_bp[0].addr         = NULL;
 498         step_bp[0].opcode[0]    = 0;
 499         step_bp[0].opcode[1]    = 0;
 500         step_bp[1].addr         = NULL;
 501         step_bp[1].opcode[0]    = 0;
 502         step_bp[1].opcode[1]    = 0;
 503         x = 0;
 504
 505         pc = (u8 *) regs->pc;
 506         sp = (u8 *) (regs + 1);
 507         if (gdbstub_read_byte(pc, &cur) < 0)
 508                 return -EFAULT;
 509
 510         gdbstub_bkpt("Single Step from %p { %02x }\n", pc, cur);
 511
 512         gdbstub_flush_caches = 1;
 513
 514         size = gdbstub_insn_sizes[cur];
 515         if (size > 0) {
 516                 if (!__gdbstub_mark_bp(pc + size, 0))
 517                         goto fault;
 518         } else {
 519                 switch (cur) {
 520                         /* Bxx (d8,PC) */
 521                 case 0xc0 ... 0xca:
 522                         if (gdbstub_read_byte(pc + 1, (u8 *) &x) < 0)
 523                                 goto fault;
 524                         if (!__gdbstub_mark_bp(pc + 2, 0))
 525                                 goto fault;
 526                         if ((x < 0 || x > 2) &&
 527                             !__gdbstub_mark_bp(pc + (s8) x, 1))
 528                                 goto fault;
 529                         break;
 530
 531                         /* LXX (d8,PC) */
 532                 case 0xd0 ... 0xda:
 533                         if (!__gdbstub_mark_bp(pc + 1, 0))
 534                                 goto fault;
 535                         if (regs->pc != regs->lar &&
 536                             !__gdbstub_mark_bp((u8 *) regs->lar, 1))
 537                                 goto fault;
 538                         break;
 539
 540                         /* SETLB - loads the next for bytes into the LIR
 541                          * register */
 542                 case 0xdb:
 543                         if (!__gdbstub_mark_bp(pc + 1, 0))
 544                                 goto fault;
 545                         break;
 546
 547                         /* JMP (d16,PC) or CALL (d16,PC) */
 548                 case 0xcc:
 549                 case 0xcd:
 550                         if (gdbstub_read_byte(pc + 1, ((u8 *) &x) + 0) < 0 ||
 551                             gdbstub_read_byte(pc + 2, ((u8 *) &x) + 1) < 0)
 552                                 goto fault;
 553                         if (!__gdbstub_mark_bp(pc + (s16) x, 0))
 554                                 goto fault;
 555                         break;
 556
 557                         /* JMP (d32,PC) or CALL (d32,PC) */
 558                 case 0xdc:
 559                 case 0xdd:
 560                         if (gdbstub_read_byte(pc + 1, ((u8 *) &x) + 0) < 0 ||
 561                             gdbstub_read_byte(pc + 2, ((u8 *) &x) + 1) < 0 ||
 562                             gdbstub_read_byte(pc + 3, ((u8 *) &x) + 2) < 0 ||
 563                             gdbstub_read_byte(pc + 4, ((u8 *) &x) + 3) < 0)
 564                                 goto fault;
 565                         if (!__gdbstub_mark_bp(pc + (s32) x, 0))
 566                                 goto fault;
 567                         break;
 568
 569                         /* RETF */
 570                 case 0xde:
 571                         if (!__gdbstub_mark_bp((u8 *) regs->mdr, 0))
 572                                 goto fault;
 573                         break;
 574
 575                         /* RET */
 576                 case 0xdf:
 577                         if (gdbstub_read_byte(pc + 2, (u8 *) &x) < 0)
 578                                 goto fault;
 579                         sp += (s8)x;
 580                         if (gdbstub_read_byte(sp + 0, ((u8 *) &x) + 0) < 0 ||
 581                             gdbstub_read_byte(sp + 1, ((u8 *) &x) + 1) < 0 ||
 582                             gdbstub_read_byte(sp + 2, ((u8 *) &x) + 2) < 0 ||
 583                             gdbstub_read_byte(sp + 3, ((u8 *) &x) + 3) < 0)
 584                                 goto fault;
 585                         if (!__gdbstub_mark_bp((u8 *) x, 0))
 586                                 goto fault;
 587                         break;
 588
 589                 case 0xf0:
 590                         if (gdbstub_read_byte(pc + 1, &cur) < 0)
 591                                 goto fault;
 592
 593                         if (cur >= 0xf0 && cur <= 0xf7) {
 594                                 /* JMP (An) / CALLS (An) */
 595                                 switch (cur & 3) {
 596                                 case 0: x = regs->a0; break;
 597                                 case 1: x = regs->a1; break;
 598                                 case 2: x = regs->a2; break;
 599                                 case 3: x = regs->a3; break;
 600                                 }
 601                                 if (!__gdbstub_mark_bp((u8 *) x, 0))
 602                                         goto fault;
 603                         } else if (cur == 0xfc) {
 604                                 /* RETS */
 605                                 if (gdbstub_read_byte(
 606                                             sp + 0, ((u8 *) &x) + 0) < 0 ||
 607                                     gdbstub_read_byte(
 608                                             sp + 1, ((u8 *) &x) + 1) < 0 ||
 609                                     gdbstub_read_byte(
 610                                             sp + 2, ((u8 *) &x) + 2) < 0 ||
 611                                     gdbstub_read_byte(
 612                                             sp + 3, ((u8 *) &x) + 3) < 0)
 613                                         goto fault;
 614                                 if (!__gdbstub_mark_bp((u8 *) x, 0))
 615                                         goto fault;
 616                         } else if (cur == 0xfd) {
 617                                 /* RTI */
 618                                 if (gdbstub_read_byte(
 619                                             sp + 4, ((u8 *) &x) + 0) < 0 ||
 620                                     gdbstub_read_byte(
 621                                             sp + 5, ((u8 *) &x) + 1) < 0 ||
 622                                     gdbstub_read_byte(
 623                                             sp + 6, ((u8 *) &x) + 2) < 0 ||
 624                                     gdbstub_read_byte(
 625                                             sp + 7, ((u8 *) &x) + 3) < 0)
 626                                         goto fault;
 627                                 if (!__gdbstub_mark_bp((u8 *) x, 0))
 628                                         goto fault;
 629                         } else {
 630                                 if (!__gdbstub_mark_bp(pc + 2, 0))
 631                                         goto fault;
 632                         }
 633
 634                         break;
 635
 636                         /* potential 3-byte conditional branches */
 637                 case 0xf8:
 638                         if (gdbstub_read_byte(pc + 1, &cur) < 0)
 639                                 goto fault;
 640                         if (!__gdbstub_mark_bp(pc + 3, 0))
 641                                 goto fault;
 642
 643                         if (cur >= 0xe8 && cur <= 0xeb) {
 644                                 if (gdbstub_read_byte(
 645                                             pc + 2, ((u8 *) &x) + 0) < 0)
 646                                         goto fault;
 647                                 if ((x < 0 || x > 3) &&
 648                                     !__gdbstub_mark_bp(pc + (s8) x, 1))
 649                                         goto fault;
 650                         }
 651                         break;
 652
 653                 case 0xfa:
 654                         if (gdbstub_read_byte(pc + 1, &cur) < 0)
 655                                 goto fault;
 656
 657                         if (cur == 0xff) {
 658                                 /* CALLS (d16,PC) */
 659                                 if (gdbstub_read_byte(
 660                                             pc + 2, ((u8 *) &x) + 0) < 0 ||
 661                                     gdbstub_read_byte(
 662                                             pc + 3, ((u8 *) &x) + 1) < 0)
 663                                         goto fault;
 664                                 if (!__gdbstub_mark_bp(pc + (s16) x, 0))
 665                                         goto fault;
 666                         } else {
 667                                 if (!__gdbstub_mark_bp(pc + 4, 0))
 668                                         goto fault;
 669                         }
 670                         break;
 671
 672                 case 0xfc:
 673                         if (gdbstub_read_byte(pc + 1, &cur) < 0)
 674                                 goto fault;
 675                         if (cur == 0xff) {
 676                                 /* CALLS (d32,PC) */
 677                                 if (gdbstub_read_byte(
 678                                             pc + 2, ((u8 *) &x) + 0) < 0 ||
 679                                     gdbstub_read_byte(
 680                                             pc + 3, ((u8 *) &x) + 1) < 0 ||
 681                                     gdbstub_read_byte(
 682                                             pc + 4, ((u8 *) &x) + 2) < 0 ||
 683                                     gdbstub_read_byte(
 684                                             pc + 5, ((u8 *) &x) + 3) < 0)
 685                                         goto fault;
 686                                 if (!__gdbstub_mark_bp(
 687                                             pc + (s32) x, 0))
 688                                         goto fault;
 689                         } else {
 690                                 if (!__gdbstub_mark_bp(
 691                                             pc + 6, 0))
 692                                         goto fault;
 693                         }
 694                         break;
 695
 696                 }
 697         }
 698
 699         gdbstub_bkpt("Step: %02x at %p; %02x at %p\n",
 700                      step_bp[0].opcode[0], step_bp[0].addr,
 701                      step_bp[1].opcode[0], step_bp[1].addr);
 702
 703         if (step_bp[0].addr) {
 704 #ifdef GDBSTUB_USE_F7F7_AS_BREAKPOINT
 705                 if (gdbstub_write_byte(0xF7, step_bp[0].addr + 0) < 0 ||
 706                     gdbstub_write_byte(0xF7, step_bp[0].addr + 1) < 0)
 707                         goto fault;
 708 #else
 709                 if (gdbstub_write_byte(0xFF, step_bp[0].addr + 0) < 0)
 710                         goto fault;
 711 #endif
 712         }
 713
 714         if (step_bp[1].addr) {
 715 #ifdef GDBSTUB_USE_F7F7_AS_BREAKPOINT
 716                 if (gdbstub_write_byte(0xF7, step_bp[1].addr + 0) < 0 ||
 717                     gdbstub_write_byte(0xF7, step_bp[1].addr + 1) < 0)
 718                         goto fault;
 719 #else
 720                 if (gdbstub_write_byte(0xFF, step_bp[1].addr + 0) < 0)
 721                         goto fault;
 722 #endif
 723         }
 724
 725         return 0;
 726
 727  fault:
 728         /* uh-oh - silly address alert, try and restore things */
 729         __gdbstub_restore_bp();
 730         return -EFAULT;
 731 }
 732
 733 #ifdef CONFIG_GDBSTUB_CONSOLE
 734
 735 void gdbstub_console_write(struct console *con, const char *p, unsigned n)
 736 {
 737         static const char gdbstub_cr[] = { 0x0d };
 738         char outbuf[26];
 739         int qty;
 740         u8 busy;
 741
 742         busy = gdbstub_busy;
 743         gdbstub_busy = 1;
 744
 745         outbuf[0] = 'O';
 746
 747         while (n > 0) {
 748                 qty = 1;
 749
 750                 while (n > 0 && qty < 20) {
 751                         mem2hex(p, outbuf + qty, 2, 0);
 752                         qty += 2;
 753                         if (*p == 0x0a) {
 754                                 mem2hex(gdbstub_cr, outbuf + qty, 2, 0);
 755                                 qty += 2;
 756                         }
 757                         p++;
 758                         n--;
 759                 }
 760
 761                 outbuf[qty] = 0;
 762                 putpacket(outbuf);
 763         }
 764
 765         gdbstub_busy = busy;
 766 }
 767
 768 static kdev_t gdbstub_console_dev(struct console *con)
 769 {
 770         return MKDEV(1, 3); /* /dev/null */
 771 }
 772
 773 static struct console gdbstub_console = {
 774         .name   = "gdb",
 775         .write  = gdbstub_console_write,
 776         .device = gdbstub_console_dev,
 777         .flags  = CON_PRINTBUFFER,
 778         .index  = -1,
 779 };
 780
 781 #endif
 782
 783 /*
 784  * Convert the memory pointed to by mem into hex, placing result in buf.
 785  * - if successful, return a pointer to the last char put in buf (NUL)
 786  * - in case of mem fault, return NULL
 787  * may_fault is non-zero if we are reading from arbitrary memory, but is
 788  * currently not used.
 789  */
 790 static
 791 unsigned char *mem2hex(const void *_mem, char *buf, int count, int may_fault)
 792 {
 793         const u8 *mem = _mem;
 794         u8 ch[4];
 795
 796         if ((u32) mem & 1 && count >= 1) {
 797                 if (gdbstub_read_byte(mem, ch) != 0)
 798                         return 0;
 799                 buf = pack_hex_byte(buf, ch[0]);
 800                 mem++;
 801                 count--;
 802         }
 803
 804         if ((u32) mem & 3 && count >= 2) {
 805                 if (gdbstub_read_word(mem, ch) != 0)
 806                         return 0;
 807                 buf = pack_hex_byte(buf, ch[0]);
 808                 buf = pack_hex_byte(buf, ch[1]);
 809                 mem += 2;
 810                 count -= 2;
 811         }
 812
 813         while (count >= 4) {
 814                 if (gdbstub_read_dword(mem, ch) != 0)
 815                         return 0;
 816                 buf = pack_hex_byte(buf, ch[0]);
 817                 buf = pack_hex_byte(buf, ch[1]);
 818                 buf = pack_hex_byte(buf, ch[2]);
 819                 buf = pack_hex_byte(buf, ch[3]);
 820                 mem += 4;
 821                 count -= 4;
 822         }
 823
 824         if (count >= 2) {
 825                 if (gdbstub_read_word(mem, ch) != 0)
 826                         return 0;
 827                 buf = pack_hex_byte(buf, ch[0]);
 828                 buf = pack_hex_byte(buf, ch[1]);
 829                 mem += 2;
 830                 count -= 2;
 831         }
 832
 833         if (count >= 1) {
 834                 if (gdbstub_read_byte(mem, ch) != 0)
 835                         return 0;
 836                 buf = pack_hex_byte(buf, ch[0]);
 837         }
 838
 839         *buf = 0;
 840         return buf;
 841 }
 842
 843 /*
 844  * convert the hex array pointed to by buf into binary to be placed in mem
 845  * return a pointer to the character AFTER the last byte written
 846  * may_fault is non-zero if we are reading from arbitrary memory, but is
 847  * currently not used.
 848  */
 849 static
 850 const char *hex2mem(const char *buf, void *_mem, int count, int may_fault)
 851 {
 852         u8 *mem = _mem;
 853         union {
 854                 u32 val;
 855                 u8 b[4];
 856         } ch;
 857
 858         if ((u32) mem & 1 && count >= 1) {
 859                 ch.b[0]  = hex(*buf++) << 4;
 860                 ch.b[0] |= hex(*buf++);
 861                 if (gdbstub_write_byte(ch.val, mem) != 0)
 862                         return 0;
 863                 mem++;
 864                 count--;
 865         }
 866
 867         if ((u32) mem & 3 && count >= 2) {
 868                 ch.b[0]  = hex(*buf++) << 4;
 869                 ch.b[0] |= hex(*buf++);
 870                 ch.b[1]  = hex(*buf++) << 4;
 871                 ch.b[1] |= hex(*buf++);
 872                 if (gdbstub_write_word(ch.val, mem) != 0)
 873                         return 0;
 874                 mem += 2;
 875                 count -= 2;
 876         }
 877
 878         while (count >= 4) {
 879                 ch.b[0]  = hex(*buf++) << 4;
 880                 ch.b[0] |= hex(*buf++);
 881                 ch.b[1]  = hex(*buf++) << 4;
 882                 ch.b[1] |= hex(*buf++);
 883                 ch.b[2]  = hex(*buf++) << 4;
 884                 ch.b[2] |= hex(*buf++);
 885                 ch.b[3]  = hex(*buf++) << 4;
 886                 ch.b[3] |= hex(*buf++);
 887                 if (gdbstub_write_dword(ch.val, mem) != 0)
 888                         return 0;
 889                 mem += 4;
 890                 count -= 4;
 891         }
 892
 893         if (count >= 2) {
 894                 ch.b[0]  = hex(*buf++) << 4;
 895                 ch.b[0] |= hex(*buf++);
 896                 ch.b[1]  = hex(*buf++) << 4;
 897                 ch.b[1] |= hex(*buf++);
 898                 if (gdbstub_write_word(ch.val, mem) != 0)
 899                         return 0;
 900                 mem += 2;
 901                 count -= 2;
 902         }
 903
 904         if (count >= 1) {
 905                 ch.b[0]  = hex(*buf++) << 4;
 906                 ch.b[0] |= hex(*buf++);
 907                 if (gdbstub_write_byte(ch.val, mem) != 0)
 908                         return 0;
 909         }
 910
 911         return buf;
 912 }
 913
 914 /*
 915  * This table contains the mapping between MN10300 exception codes, and
 916  * signals, which are primarily what GDB understands.  It also indicates
 917  * which hardware traps we need to commandeer when initializing the stub.
 918  */
 919 static const struct excep_to_sig_map {
 920         enum exception_code     excep;  /* MN10300 exception code */
 921         unsigned char           signo;  /* Signal that we map this into */
 922 } excep_to_sig_map[] = {
 923         { EXCEP_ITLBMISS,       SIGSEGV         },
 924         { EXCEP_DTLBMISS,       SIGSEGV         },
 925         { EXCEP_TRAP,           SIGTRAP         },
 926         { EXCEP_ISTEP,          SIGTRAP         },
 927         { EXCEP_IBREAK,         SIGTRAP         },
 928         { EXCEP_OBREAK,         SIGTRAP         },
 929         { EXCEP_UNIMPINS,       SIGILL          },
 930         { EXCEP_UNIMPEXINS,     SIGILL          },
 931         { EXCEP_MEMERR,         SIGSEGV         },
 932         { EXCEP_MISALIGN,       SIGSEGV         },
 933         { EXCEP_BUSERROR,       SIGBUS          },
 934         { EXCEP_ILLINSACC,      SIGSEGV         },
 935         { EXCEP_ILLDATACC,      SIGSEGV         },
 936         { EXCEP_IOINSACC,       SIGSEGV         },
 937         { EXCEP_PRIVINSACC,     SIGSEGV         },
 938         { EXCEP_PRIVDATACC,     SIGSEGV         },
 939         { EXCEP_FPU_DISABLED,   SIGFPE          },
 940         { EXCEP_FPU_UNIMPINS,   SIGFPE          },
 941         { EXCEP_FPU_OPERATION,  SIGFPE          },
 942         { EXCEP_WDT,            SIGALRM         },
 943         { EXCEP_NMI,            SIGQUIT         },
 944         { EXCEP_IRQ_LEVEL0,     SIGINT          },
 945         { EXCEP_IRQ_LEVEL1,     SIGINT          },
 946         { EXCEP_IRQ_LEVEL2,     SIGINT          },
 947         { EXCEP_IRQ_LEVEL3,     SIGINT          },
 948         { EXCEP_IRQ_LEVEL4,     SIGINT          },
 949         { EXCEP_IRQ_LEVEL5,     SIGINT          },
 950         { EXCEP_IRQ_LEVEL6,     SIGINT          },
 951         { 0, 0}
 952 };
 953
 954 /*
 955  * convert the MN10300 exception code into a UNIX signal number
 956  */
 957 static int computeSignal(enum exception_code excep)
 958 {
 959         const struct excep_to_sig_map *map;
 960
 961         for (map = excep_to_sig_map; map->signo; map++)
 962                 if (map->excep == excep)
 963                         return map->signo;
 964
 965         return SIGHUP; /* default for things we don't know about */
 966 }
 967
 968 static u32 gdbstub_fpcr, gdbstub_fpufs_array[32];
 969
 970 /*
 971  *
 972  */
 973 static void gdbstub_store_fpu(void)
 974 {
 975 #ifdef CONFIG_FPU
 976
 977         asm volatile(
 978                 "or %2,epsw\n"
 979 #ifdef CONFIG_MN10300_PROC_MN103E010
 980                 "nop\n"
 981                 "nop\n"
 982 #endif
 983                 "mov %1, a1\n"
 984                 "fmov fs0,  (a1+)\n"
 985                 "fmov fs1,  (a1+)\n"
 986                 "fmov fs2,  (a1+)\n"
 987                 "fmov fs3,  (a1+)\n"
 988                 "fmov fs4,  (a1+)\n"
 989                 "fmov fs5,  (a1+)\n"
 990                 "fmov fs6,  (a1+)\n"
 991                 "fmov fs7,  (a1+)\n"
 992                 "fmov fs8,  (a1+)\n"
 993                 "fmov fs9,  (a1+)\n"
 994                 "fmov fs10, (a1+)\n"
 995                 "fmov fs11, (a1+)\n"
 996                 "fmov fs12, (a1+)\n"
 997                 "fmov fs13, (a1+)\n"
 998                 "fmov fs14, (a1+)\n"
 999                 "fmov fs15, (a1+)\n"
1000                 "fmov fs16, (a1+)\n"
1001                 "fmov fs17, (a1+)\n"
1002                 "fmov fs18, (a1+)\n"
1003                 "fmov fs19, (a1+)\n"
1004                 "fmov fs20, (a1+)\n"
1005                 "fmov fs21, (a1+)\n"
1006                 "fmov fs22, (a1+)\n"
1007                 "fmov fs23, (a1+)\n"
1008                 "fmov fs24, (a1+)\n"
1009                 "fmov fs25, (a1+)\n"
1010                 "fmov fs26, (a1+)\n"
1011                 "fmov fs27, (a1+)\n"
1012                 "fmov fs28, (a1+)\n"
1013                 "fmov fs29, (a1+)\n"
1014                 "fmov fs30, (a1+)\n"
1015                 "fmov fs31, (a1+)\n"
1016                 "fmov fpcr, %0\n"
1017                 : "=d"(gdbstub_fpcr)
1018                 : "g" (&gdbstub_fpufs_array), "i"(EPSW_FE)
1019                 : "a1"
1020                 );
1021 #endif
1022 }
1023
1024 /*
1025  *
1026  */
1027 static void gdbstub_load_fpu(void)
1028 {
1029 #ifdef CONFIG_FPU
1030
1031         asm volatile(
1032                 "or %1,epsw\n"
1033 #ifdef CONFIG_MN10300_PROC_MN103E010
1034                 "nop\n"
1035                 "nop\n"
1036 #endif
1037                 "mov %0, a1\n"
1038                 "fmov (a1+), fs0\n"
1039                 "fmov (a1+), fs1\n"
1040                 "fmov (a1+), fs2\n"
1041                 "fmov (a1+), fs3\n"
1042                 "fmov (a1+), fs4\n"
1043                 "fmov (a1+), fs5\n"
1044                 "fmov (a1+), fs6\n"
1045                 "fmov (a1+), fs7\n"
1046                 "fmov (a1+), fs8\n"
1047                 "fmov (a1+), fs9\n"
1048                 "fmov (a1+), fs10\n"
1049                 "fmov (a1+), fs11\n"
1050                 "fmov (a1+), fs12\n"
1051                 "fmov (a1+), fs13\n"
1052                 "fmov (a1+), fs14\n"
1053                 "fmov (a1+), fs15\n"
1054                 "fmov (a1+), fs16\n"
1055                 "fmov (a1+), fs17\n"
1056                 "fmov (a1+), fs18\n"
1057                 "fmov (a1+), fs19\n"
1058                 "fmov (a1+), fs20\n"
1059                 "fmov (a1+), fs21\n"
1060                 "fmov (a1+), fs22\n"
1061                 "fmov (a1+), fs23\n"
1062                 "fmov (a1+), fs24\n"
1063                 "fmov (a1+), fs25\n"
1064                 "fmov (a1+), fs26\n"
1065                 "fmov (a1+), fs27\n"
1066                 "fmov (a1+), fs28\n"
1067                 "fmov (a1+), fs29\n"
1068                 "fmov (a1+), fs30\n"
1069                 "fmov (a1+), fs31\n"
1070                 "fmov %2, fpcr\n"
1071                 :
1072                 : "g" (&gdbstub_fpufs_array), "i"(EPSW_FE), "d"(gdbstub_fpcr)
1073                 : "a1"
1074         );
1075 #endif
1076 }
1077
1078 /*
1079  * set a software breakpoint
1080  */
1081 int gdbstub_set_breakpoint(u8 *addr, int len)
1082 {
1083         int bkpt, loop, xloop;
1084
1085 #ifdef GDBSTUB_USE_F7F7_AS_BREAKPOINT
1086         len = (len + 1) & ~1;
1087 #endif
1088
1089         gdbstub_bkpt("setbkpt(%p,%d)\n", addr, len);
1090
1091         for (bkpt = 255; bkpt >= 0; bkpt--)
1092                 if (!gdbstub_bkpts[bkpt].addr)
1093                         break;
1094         if (bkpt < 0)
1095                 return -ENOSPC;
1096
1097         for (loop = 0; loop < len; loop++)
1098                 if (gdbstub_read_byte(&addr[loop],
1099                                       &gdbstub_bkpts[bkpt].origbytes[loop]
1100                                       ) < 0)
1101                         return -EFAULT;
1102
1103         gdbstub_flush_caches = 1;
1104
1105 #ifdef GDBSTUB_USE_F7F7_AS_BREAKPOINT
1106         for (loop = 0; loop < len; loop++)
1107                 if (gdbstub_write_byte(0xF7, &addr[loop]) < 0)
1108                         goto restore;
1109 #else
1110         for (loop = 0; loop < len; loop++)
1111                 if (gdbstub_write_byte(0xFF, &addr[loop]) < 0)
1112                         goto restore;
1113 #endif
1114
1115         gdbstub_bkpts[bkpt].addr = addr;
1116         gdbstub_bkpts[bkpt].len = len;
1117
1118         gdbstub_bkpt("Set BKPT[%02x]: %p-%p {%02x%02x%02x%02x%02x%02x%02x}\n",
1119                      bkpt,
1120                      gdbstub_bkpts[bkpt].addr,
1121                      gdbstub_bkpts[bkpt].addr + gdbstub_bkpts[bkpt].len - 1,
1122                      gdbstub_bkpts[bkpt].origbytes[0],
1123                      gdbstub_bkpts[bkpt].origbytes[1],
1124                      gdbstub_bkpts[bkpt].origbytes[2],
1125                      gdbstub_bkpts[bkpt].origbytes[3],
1126                      gdbstub_bkpts[bkpt].origbytes[4],
1127                      gdbstub_bkpts[bkpt].origbytes[5],
1128                      gdbstub_bkpts[bkpt].origbytes[6]
1129                      );
1130
1131         return 0;
1132
1133 restore:
1134         for (xloop = 0; xloop < loop; xloop++)
1135                 gdbstub_write_byte(gdbstub_bkpts[bkpt].origbytes[xloop],
1136                                    addr + xloop);
1137         return -EFAULT;
1138 }
1139
1140 /*
1141  * clear a software breakpoint
1142  */
1143 int gdbstub_clear_breakpoint(u8 *addr, int len)
1144 {
1145         int bkpt, loop;
1146
1147 #ifdef GDBSTUB_USE_F7F7_AS_BREAKPOINT
1148         len = (len + 1) & ~1;
1149 #endif
1150
1151         gdbstub_bkpt("clearbkpt(%p,%d)\n", addr, len);
1152
1153         for (bkpt = 255; bkpt >= 0; bkpt--)
1154                 if (gdbstub_bkpts[bkpt].addr == addr &&
1155                     gdbstub_bkpts[bkpt].len == len)
1156                         break;
1157         if (bkpt < 0)
1158                 return -ENOENT;
1159
1160         gdbstub_bkpts[bkpt].addr = NULL;
1161
1162         gdbstub_flush_caches = 1;
1163
1164         for (loop = 0; loop < len; loop++)
1165                 if (gdbstub_write_byte(gdbstub_bkpts[bkpt].origbytes[loop],
1166                                        addr + loop) < 0)
1167                         return -EFAULT;
1168
1169         return 0;
1170 }
1171
1172 /*
1173  * This function does all command processing for interfacing to gdb
1174  * - returns 1 if the exception should be skipped, 0 otherwise.
1175  */
1176 static int gdbstub(struct pt_regs *regs, enum exception_code excep)
1177 {
1178         unsigned long *stack;
1179         unsigned long epsw, mdr;
1180         uint32_t zero, ssp;
1181         uint8_t broke;
1182         char *ptr;
1183         int sigval;
1184         int addr;
1185         int length;
1186         int loop;
1187
1188         if (excep == EXCEP_FPU_DISABLED)
1189                 return 0;
1190
1191         gdbstub_flush_caches = 0;
1192
1193         mn10300_set_gdbleds(1);
1194
1195         asm volatile("mov mdr,%0" : "=d"(mdr));
1196         local_save_flags(epsw);
1197         arch_local_change_intr_mask_level(
1198                 NUM2EPSW_IM(CONFIG_GDBSTUB_IRQ_LEVEL + 1));
1199
1200         gdbstub_store_fpu();
1201
1202 #ifdef CONFIG_GDBSTUB_IMMEDIATE
1203         /* skip the initial pause loop */
1204         if (regs->pc == (unsigned long) __gdbstub_pause)
1205                 regs->pc = (unsigned long) start_kernel;
1206 #endif
1207
1208         /* if we were single stepping, restore the opcodes hoisted for the
1209          * breakpoint[s] */
1210         broke = 0;
1211         if ((step_bp[0].addr && step_bp[0].addr == (u8 *) regs->pc) ||
1212             (step_bp[1].addr && step_bp[1].addr == (u8 *) regs->pc))
1213                 broke = 1;
1214
1215         __gdbstub_restore_bp();
1216
1217         if (gdbstub_rx_unget) {
1218                 sigval = SIGINT;
1219                 if (gdbstub_rx_unget != 3)
1220                         goto packet_waiting;
1221                 gdbstub_rx_unget = 0;
1222         }
1223
1224         stack = (unsigned long *) regs->sp;
1225         sigval = broke ? SIGTRAP : computeSignal(excep);
1226
1227         /* send information about a BUG() */
1228         if (!user_mode(regs) && excep == EXCEP_SYSCALL15) {
1229                 const struct bug_entry *bug;
1230
1231                 bug = find_bug(regs->pc);
1232                 if (bug)
1233                         goto found_bug;
1234                 length = snprintf(trans_buffer, sizeof(trans_buffer),
1235                                   "BUG() at address %lx\n", regs->pc);
1236                 goto send_bug_pkt;
1237
1238         found_bug:
1239                 length = snprintf(trans_buffer, sizeof(trans_buffer),
1240                                   "BUG() at address %lx (%s:%d)\n",
1241                                   regs->pc, bug->file, bug->line);
1242
1243         send_bug_pkt:
1244                 ptr = output_buffer;
1245                 *ptr++ = 'O';
1246                 ptr = mem2hex(trans_buffer, ptr, length, 0);
1247                 *ptr = 0;
1248                 putpacket(output_buffer);
1249
1250                 regs->pc -= 2;
1251                 sigval = SIGABRT;
1252         } else if (regs->pc == (unsigned long) __gdbstub_bug_trap) {
1253                 regs->pc = regs->mdr;
1254                 sigval = SIGABRT;
1255         }
1256
1257         /*
1258          * send a message to the debugger's user saying what happened if it may
1259          * not be clear cut (we can't map exceptions onto signals properly)
1260          */
1261         if (sigval != SIGINT && sigval != SIGTRAP && sigval != SIGILL) {
1262                 static const char title[] = "Excep ", tbcberr[] = "BCBERR ";
1263                 static const char crlf[] = "\r\n";
1264                 char hx;
1265                 u32 bcberr = BCBERR;
1266
1267                 ptr = output_buffer;
1268                 *ptr++ = 'O';
1269                 ptr = mem2hex(title, ptr, sizeof(title) - 1, 0);
1270
1271                 hx = hex_asc_hi(excep >> 8);
1272                 ptr = pack_hex_byte(ptr, hx);
1273                 hx = hex_asc_lo(excep >> 8);
1274                 ptr = pack_hex_byte(ptr, hx);
1275                 hx = hex_asc_hi(excep);
1276                 ptr = pack_hex_byte(ptr, hx);
1277                 hx = hex_asc_lo(excep);
1278                 ptr = pack_hex_byte(ptr, hx);
1279
1280                 ptr = mem2hex(crlf, ptr, sizeof(crlf) - 1, 0);
1281                 *ptr = 0;
1282                 putpacket(output_buffer);       /* send it off... */
1283
1284                 /* BCBERR */
1285                 ptr = output_buffer;
1286                 *ptr++ = 'O';
1287                 ptr = mem2hex(tbcberr, ptr, sizeof(tbcberr) - 1, 0);
1288
1289                 hx = hex_asc_hi(bcberr >> 24);
1290                 ptr = pack_hex_byte(ptr, hx);
1291                 hx = hex_asc_lo(bcberr >> 24);
1292                 ptr = pack_hex_byte(ptr, hx);
1293                 hx = hex_asc_hi(bcberr >> 16);
1294                 ptr = pack_hex_byte(ptr, hx);
1295                 hx = hex_asc_lo(bcberr >> 16);
1296                 ptr = pack_hex_byte(ptr, hx);
1297                 hx = hex_asc_hi(bcberr >> 8);
1298                 ptr = pack_hex_byte(ptr, hx);
1299                 hx = hex_asc_lo(bcberr >> 8);
1300                 ptr = pack_hex_byte(ptr, hx);
1301                 hx = hex_asc_hi(bcberr);
1302                 ptr = pack_hex_byte(ptr, hx);
1303                 hx = hex_asc_lo(bcberr);
1304                 ptr = pack_hex_byte(ptr, hx);
1305
1306                 ptr = mem2hex(crlf, ptr, sizeof(crlf) - 1, 0);
1307                 *ptr = 0;
1308                 putpacket(output_buffer);       /* send it off... */
1309         }
1310
1311         /*
1312          * tell the debugger that an exception has occurred
1313          */
1314         ptr = output_buffer;
1315
1316         /*
1317          * Send trap type (converted to signal)
1318          */
1319         *ptr++ = 'T';
1320         ptr = pack_hex_byte(ptr, sigval);
1321
1322         /*
1323          * Send Error PC
1324          */
1325         ptr = pack_hex_byte(ptr, GDB_REGID_PC);
1326         *ptr++ = ':';
1327         ptr = mem2hex(&regs->pc, ptr, 4, 0);
1328         *ptr++ = ';';
1329
1330         /*
1331          * Send frame pointer
1332          */
1333         ptr = pack_hex_byte(ptr, GDB_REGID_FP);
1334         *ptr++ = ':';
1335         ptr = mem2hex(&regs->a3, ptr, 4, 0);
1336         *ptr++ = ';';
1337
1338         /*
1339          * Send stack pointer
1340          */
1341         ssp = (unsigned long) (regs + 1);
1342         ptr = pack_hex_byte(ptr, GDB_REGID_SP);
1343         *ptr++ = ':';
1344         ptr = mem2hex(&ssp, ptr, 4, 0);
1345         *ptr++ = ';';
1346
1347         *ptr++ = 0;
1348         putpacket(output_buffer);       /* send it off... */
1349
1350 packet_waiting:
1351         /*
1352          * Wait for input from remote GDB
1353          */
1354         while (1) {
1355                 output_buffer[0] = 0;
1356                 getpacket(input_buffer);
1357
1358                 switch (input_buffer[0]) {
1359                         /* request repeat of last signal number */
1360                 case '?':
1361                         output_buffer[0] = 'S';
1362                         output_buffer[1] = hex_asc_hi(sigval);
1363                         output_buffer[2] = hex_asc_lo(sigval);
1364                         output_buffer[3] = 0;
1365                         break;
1366
1367                 case 'd':
1368                         /* toggle debug flag */
1369                         break;
1370
1371                         /*
1372                          * Return the value of the CPU registers
1373                          */
1374                 case 'g':
1375                         zero = 0;
1376                         ssp = (u32) (regs + 1);
1377                         ptr = output_buffer;
1378                         ptr = mem2hex(&regs->d0, ptr, 4, 0);
1379                         ptr = mem2hex(&regs->d1, ptr, 4, 0);
1380                         ptr = mem2hex(&regs->d2, ptr, 4, 0);
1381                         ptr = mem2hex(&regs->d3, ptr, 4, 0);
1382                         ptr = mem2hex(&regs->a0, ptr, 4, 0);
1383                         ptr = mem2hex(&regs->a1, ptr, 4, 0);
1384                         ptr = mem2hex(&regs->a2, ptr, 4, 0);
1385                         ptr = mem2hex(&regs->a3, ptr, 4, 0);
1386
1387                         ptr = mem2hex(&ssp, ptr, 4, 0);         /* 8 */
1388                         ptr = mem2hex(&regs->pc, ptr, 4, 0);
1389                         ptr = mem2hex(&regs->mdr, ptr, 4, 0);
1390                         ptr = mem2hex(&regs->epsw, ptr, 4, 0);
1391                         ptr = mem2hex(&regs->lir, ptr, 4, 0);
1392                         ptr = mem2hex(&regs->lar, ptr, 4, 0);
1393                         ptr = mem2hex(&regs->mdrq, ptr, 4, 0);
1394
1395                         ptr = mem2hex(&regs->e0, ptr, 4, 0);    /* 15 */
1396                         ptr = mem2hex(&regs->e1, ptr, 4, 0);
1397                         ptr = mem2hex(&regs->e2, ptr, 4, 0);
1398                         ptr = mem2hex(&regs->e3, ptr, 4, 0);
1399                         ptr = mem2hex(&regs->e4, ptr, 4, 0);
1400                         ptr = mem2hex(&regs->e5, ptr, 4, 0);
1401                         ptr = mem2hex(&regs->e6, ptr, 4, 0);
1402                         ptr = mem2hex(&regs->e7, ptr, 4, 0);
1403
1404                         ptr = mem2hex(&ssp, ptr, 4, 0);
1405                         ptr = mem2hex(&regs, ptr, 4, 0);
1406                         ptr = mem2hex(&regs->sp, ptr, 4, 0);
1407                         ptr = mem2hex(&regs->mcrh, ptr, 4, 0);  /* 26 */
1408                         ptr = mem2hex(&regs->mcrl, ptr, 4, 0);
1409                         ptr = mem2hex(&regs->mcvf, ptr, 4, 0);
1410
1411                         ptr = mem2hex(&gdbstub_fpcr, ptr, 4, 0); /* 29 - FPCR */
1412                         ptr = mem2hex(&zero, ptr, 4, 0);
1413                         ptr = mem2hex(&zero, ptr, 4, 0);
1414                         for (loop = 0; loop < 32; loop++)
1415                                 ptr = mem2hex(&gdbstub_fpufs_array[loop],
1416                                               ptr, 4, 0); /* 32 - FS0-31 */
1417
1418                         break;
1419
1420                         /*
1421                          * set the value of the CPU registers - return OK
1422                          */
1423                 case 'G':
1424                 {
1425                         const char *ptr;
1426
1427                         ptr = &input_buffer[1];
1428                         ptr = hex2mem(ptr, &regs->d0, 4, 0);
1429                         ptr = hex2mem(ptr, &regs->d1, 4, 0);
1430                         ptr = hex2mem(ptr, &regs->d2, 4, 0);
1431                         ptr = hex2mem(ptr, &regs->d3, 4, 0);
1432                         ptr = hex2mem(ptr, &regs->a0, 4, 0);
1433                         ptr = hex2mem(ptr, &regs->a1, 4, 0);
1434                         ptr = hex2mem(ptr, &regs->a2, 4, 0);
1435                         ptr = hex2mem(ptr, &regs->a3, 4, 0);
1436
1437                         ptr = hex2mem(ptr, &ssp, 4, 0);         /* 8 */
1438                         ptr = hex2mem(ptr, &regs->pc, 4, 0);
1439                         ptr = hex2mem(ptr, &regs->mdr, 4, 0);
1440                         ptr = hex2mem(ptr, &regs->epsw, 4, 0);
1441                         ptr = hex2mem(ptr, &regs->lir, 4, 0);
1442                         ptr = hex2mem(ptr, &regs->lar, 4, 0);
1443                         ptr = hex2mem(ptr, &regs->mdrq, 4, 0);
1444
1445                         ptr = hex2mem(ptr, &regs->e0, 4, 0);    /* 15 */
1446                         ptr = hex2mem(ptr, &regs->e1, 4, 0);
1447                         ptr = hex2mem(ptr, &regs->e2, 4, 0);
1448                         ptr = hex2mem(ptr, &regs->e3, 4, 0);
1449                         ptr = hex2mem(ptr, &regs->e4, 4, 0);
1450                         ptr = hex2mem(ptr, &regs->e5, 4, 0);
1451                         ptr = hex2mem(ptr, &regs->e6, 4, 0);
1452                         ptr = hex2mem(ptr, &regs->e7, 4, 0);
1453
1454                         ptr = hex2mem(ptr, &ssp, 4, 0);
1455                         ptr = hex2mem(ptr, &zero, 4, 0);
1456                         ptr = hex2mem(ptr, &regs->sp, 4, 0);
1457                         ptr = hex2mem(ptr, &regs->mcrh, 4, 0);  /* 26 */
1458                         ptr = hex2mem(ptr, &regs->mcrl, 4, 0);
1459                         ptr = hex2mem(ptr, &regs->mcvf, 4, 0);
1460
1461                         ptr = hex2mem(ptr, &zero, 4, 0);        /* 29 - FPCR */
1462                         ptr = hex2mem(ptr, &zero, 4, 0);
1463                         ptr = hex2mem(ptr, &zero, 4, 0);
1464                         for (loop = 0; loop < 32; loop++)     /* 32 - FS0-31 */
1465                                 ptr = hex2mem(ptr, &zero, 4, 0);
1466
1467 #if 0
1468                         /*
1469                          * See if the stack pointer has moved. If so, then copy
1470                          * the saved locals and ins to the new location.
1471                          */
1472                         unsigned long *newsp = (unsigned long *) registers[SP];
1473                         if (sp != newsp)
1474                                 sp = memcpy(newsp, sp, 16 * 4);
1475 #endif
1476
1477                         gdbstub_strcpy(output_buffer, "OK");
1478                 }
1479                 break;
1480
1481                 /*
1482                  * mAA..AA,LLLL  Read LLLL bytes at address AA..AA
1483                  */
1484                 case 'm':
1485                         ptr = &input_buffer[1];
1486
1487                         if (hexToInt(&ptr, &addr) &&
1488                             *ptr++ == ',' &&
1489                             hexToInt(&ptr, &length)
1490                             ) {
1491                                 if (mem2hex((char *) addr, output_buffer,
1492                                             length, 1))
1493                                         break;
1494                                 gdbstub_strcpy(output_buffer, "E03");
1495                         } else {
1496                                 gdbstub_strcpy(output_buffer, "E01");
1497                         }
1498                         break;
1499
1500                         /*
1501                          * MAA..AA,LLLL: Write LLLL bytes at address AA.AA
1502                          * return OK
1503                          */
1504                 case 'M':
1505                         ptr = &input_buffer[1];
1506
1507                         if (hexToInt(&ptr, &addr) &&
1508                             *ptr++ == ',' &&
1509                             hexToInt(&ptr, &length) &&
1510                             *ptr++ == ':'
1511                             ) {
1512                                 if (hex2mem(ptr, (char *) addr, length, 1))
1513                                         gdbstub_strcpy(output_buffer, "OK");
1514                                 else
1515                                         gdbstub_strcpy(output_buffer, "E03");
1516
1517                                 gdbstub_flush_caches = 1;
1518                         } else {
1519                                 gdbstub_strcpy(output_buffer, "E02");
1520                         }
1521                         break;
1522
1523                         /*
1524                          * cAA..AA    Continue at address AA..AA(optional)
1525                          */
1526                 case 'c':
1527                         /* try to read optional parameter, pc unchanged if no
1528                          * parm */
1529
1530                         ptr = &input_buffer[1];
1531                         if (hexToInt(&ptr, &addr))
1532                                 regs->pc = addr;
1533                         goto done;
1534
1535                         /*
1536                          * kill the program
1537                          */
1538                 case 'k' :
1539                         goto done;      /* just continue */
1540
1541                         /*
1542                          * Reset the whole machine (FIXME: system dependent)
1543                          */
1544                 case 'r':
1545                         break;
1546
1547                         /*
1548                          * Step to next instruction
1549                          */
1550                 case 's':
1551                         /*
1552                          * using the T flag doesn't seem to perform single
1553                          * stepping (it seems to wind up being caught by the
1554                          * JTAG unit), so we have to use breakpoints and
1555                          * continue instead.
1556                          */
1557                         if (gdbstub_single_step(regs) < 0)
1558                                 /* ignore any fault error for now */
1559                                 gdbstub_printk("unable to set single-step"
1560                                                " bp\n");
1561                         goto done;
1562
1563                         /*
1564                          * Set baud rate (bBB)
1565                          */
1566                 case 'b':
1567                         do {
1568                                 int baudrate;
1569
1570                                 ptr = &input_buffer[1];
1571                                 if (!hexToInt(&ptr, &baudrate)) {
1572                                         gdbstub_strcpy(output_buffer, "B01");
1573                                         break;
1574                                 }
1575
1576                                 if (baudrate) {
1577                                         /* ACK before changing speed */
1578                                         putpacket("OK");
1579                                         gdbstub_io_set_baud(baudrate);
1580                                 }
1581                         } while (0);
1582                         break;
1583
1584                         /*
1585                          * Set breakpoint
1586                          */
1587                 case 'Z':
1588                         ptr = &input_buffer[1];
1589
1590                         if (!hexToInt(&ptr, &loop) || *ptr++ != ',' ||
1591                             !hexToInt(&ptr, &addr) || *ptr++ != ',' ||
1592                             !hexToInt(&ptr, &length)
1593                             ) {
1594                                 gdbstub_strcpy(output_buffer, "E01");
1595                                 break;
1596                         }
1597
1598                         /* only support software breakpoints */
1599                         gdbstub_strcpy(output_buffer, "E03");
1600                         if (loop != 0 ||
1601                             length < 1 ||
1602                             length > 7 ||
1603                             (unsigned long) addr < 4096)
1604                                 break;
1605
1606                         if (gdbstub_set_breakpoint((u8 *) addr, length) < 0)
1607                                 break;
1608
1609                         gdbstub_strcpy(output_buffer, "OK");
1610                         break;
1611
1612                         /*
1613                          * Clear breakpoint
1614                          */
1615                 case 'z':
1616                         ptr = &input_buffer[1];
1617
1618                         if (!hexToInt(&ptr, &loop) || *ptr++ != ',' ||
1619                             !hexToInt(&ptr, &addr) || *ptr++ != ',' ||
1620                             !hexToInt(&ptr, &length)
1621                             ) {
1622                                 gdbstub_strcpy(output_buffer, "E01");
1623                                 break;
1624                         }
1625
1626                         /* only support software breakpoints */
1627                         gdbstub_strcpy(output_buffer, "E03");
1628                         if (loop != 0 ||
1629                             length < 1 ||
1630                             length > 7 ||
1631                             (unsigned long) addr < 4096)
1632                                 break;
1633
1634                         if (gdbstub_clear_breakpoint((u8 *) addr, length) < 0)
1635                                 break;
1636
1637                         gdbstub_strcpy(output_buffer, "OK");
1638                         break;
1639
1640                 default:
1641                         gdbstub_proto("### GDB Unsupported Cmd '%s'\n",
1642                                       input_buffer);
1643                         break;
1644                 }
1645
1646                 /* reply to the request */
1647                 putpacket(output_buffer);
1648         }
1649
1650 done:
1651         /*
1652          * Need to flush the instruction cache here, as we may
1653          * have deposited a breakpoint, and the icache probably
1654          * has no way of knowing that a data ref to some location
1655          * may have changed something that is in the instruction
1656          * cache.
1657          * NB: We flush both caches, just to be sure...
1658          */
1659         if (gdbstub_flush_caches)
1660                 gdbstub_purge_cache();
1661
1662         gdbstub_load_fpu();
1663         mn10300_set_gdbleds(0);
1664         if (excep == EXCEP_NMI)
1665                 NMICR = NMICR_NMIF;
1666
1667         touch_softlockup_watchdog();
1668
1669         local_irq_restore(epsw);
1670         return 1;
1671 }
1672
1673 /*
1674  * handle event interception
1675  */
1676 asmlinkage int gdbstub_intercept(struct pt_regs *regs,
1677                                  enum exception_code excep)
1678 {
1679         static u8 notfirst = 1;
1680         int ret;
1681
1682         if (gdbstub_busy)
1683                 gdbstub_printk("--> gdbstub reentered itself\n");
1684         gdbstub_busy = 1;
1685
1686         if (notfirst) {
1687                 unsigned long mdr;
1688                 asm("mov mdr,%0" : "=d"(mdr));
1689
1690                 gdbstub_entry(
1691                         "--> gdbstub_intercept(%p,%04x) [MDR=%lx PC=%lx]\n",
1692                         regs, excep, mdr, regs->pc);
1693
1694                 gdbstub_entry(
1695                         "PC:  %08lx EPSW:  %08lx  SSP: %08lx mode: %s\n",
1696                         regs->pc, regs->epsw, (unsigned long) &ret,
1697                         user_mode(regs) ? "User" : "Super");
1698                 gdbstub_entry(
1699                         "d0:  %08lx   d1:  %08lx   d2: %08lx   d3: %08lx\n",
1700                         regs->d0, regs->d1, regs->d2, regs->d3);
1701                 gdbstub_entry(
1702                         "a0:  %08lx   a1:  %08lx   a2: %08lx   a3: %08lx\n",
1703                         regs->a0, regs->a1, regs->a2, regs->a3);
1704                 gdbstub_entry(
1705                         "e0:  %08lx   e1:  %08lx   e2: %08lx   e3: %08lx\n",
1706                         regs->e0, regs->e1, regs->e2, regs->e3);
1707                 gdbstub_entry(
1708                         "e4:  %08lx   e5:  %08lx   e6: %08lx   e7: %08lx\n",
1709                         regs->e4, regs->e5, regs->e6, regs->e7);
1710                 gdbstub_entry(
1711                         "lar: %08lx   lir: %08lx  mdr: %08lx  usp: %08lx\n",
1712                         regs->lar, regs->lir, regs->mdr, regs->sp);
1713                 gdbstub_entry(
1714                         "cvf: %08lx   crl: %08lx  crh: %08lx  drq: %08lx\n",
1715                         regs->mcvf, regs->mcrl, regs->mcrh, regs->mdrq);
1716                 gdbstub_entry(
1717                         "threadinfo=%p task=%p)\n",
1718                         current_thread_info(), current);
1719         } else {
1720                 notfirst = 1;
1721         }
1722
1723         ret = gdbstub(regs, excep);
1724
1725         gdbstub_entry("<-- gdbstub_intercept()\n");
1726         gdbstub_busy = 0;
1727         return ret;
1728 }
1729
1730 /*
1731  * handle the GDB stub itself causing an exception
1732  */
1733 asmlinkage void gdbstub_exception(struct pt_regs *regs,
1734                                   enum exception_code excep)
1735 {
1736         unsigned long mdr;
1737
1738         asm("mov mdr,%0" : "=d"(mdr));
1739         gdbstub_entry("--> gdbstub exception({%p},%04x) [MDR=%lx]\n",
1740                       regs, excep, mdr);
1741
1742         while ((unsigned long) regs == 0xffffffff) {}
1743
1744         /* handle guarded memory accesses where we know it might fault */
1745         if (regs->pc == (unsigned) gdbstub_read_byte_guard) {
1746                 regs->pc = (unsigned) gdbstub_read_byte_cont;
1747                 goto fault;
1748         }
1749
1750         if (regs->pc == (unsigned) gdbstub_read_word_guard) {
1751                 regs->pc = (unsigned) gdbstub_read_word_cont;
1752                 goto fault;
1753         }
1754
1755         if (regs->pc == (unsigned) gdbstub_read_dword_guard) {
1756                 regs->pc = (unsigned) gdbstub_read_dword_cont;
1757                 goto fault;
1758         }
1759
1760         if (regs->pc == (unsigned) gdbstub_write_byte_guard) {
1761                 regs->pc = (unsigned) gdbstub_write_byte_cont;
1762                 goto fault;
1763         }
1764
1765         if (regs->pc == (unsigned) gdbstub_write_word_guard) {
1766                 regs->pc = (unsigned) gdbstub_write_word_cont;
1767                 goto fault;
1768         }
1769
1770         if (regs->pc == (unsigned) gdbstub_write_dword_guard) {
1771                 regs->pc = (unsigned) gdbstub_write_dword_cont;
1772                 goto fault;
1773         }
1774
1775         gdbstub_printk("\n### GDB stub caused an exception ###\n");
1776
1777         /* something went horribly wrong */
1778         console_verbose();
1779         show_registers(regs);
1780
1781         panic("GDB Stub caused an unexpected exception - can't continue\n");
1782
1783         /* we caught an attempt by the stub to access silly memory */
1784 fault:
1785         gdbstub_entry("<-- gdbstub exception() = EFAULT\n");
1786         regs->d0 = -EFAULT;
1787         return;
1788 }
1789
1790 /*
1791  * send an exit message to GDB
1792  */
1793 void gdbstub_exit(int status)
1794 {
1795         unsigned char checksum;
1796         unsigned char ch;
1797         int count;
1798
1799         gdbstub_busy = 1;
1800         output_buffer[0] = 'W';
1801         output_buffer[1] = hex_asc_hi(status);
1802         output_buffer[2] = hex_asc_lo(status);
1803         output_buffer[3] = 0;
1804
1805         gdbstub_io_tx_char('$');
1806         checksum = 0;
1807         count = 0;
1808
1809         while ((ch = output_buffer[count]) != 0) {
1810                 gdbstub_io_tx_char(ch);
1811                 checksum += ch;
1812                 count += 1;
1813         }
1814
1815         gdbstub_io_tx_char('#');
1816         gdbstub_io_tx_char(hex_asc_hi(checksum));
1817         gdbstub_io_tx_char(hex_asc_lo(checksum));
1818
1819         /* make sure the output is flushed, or else RedBoot might clobber it */
1820         gdbstub_io_tx_flush();
1821
1822         gdbstub_busy = 0;
1823 }
1824
1825 /*
1826  * initialise the GDB stub
1827  */
1828 asmlinkage void __init gdbstub_init(void)
1829 {
1830 #ifdef CONFIG_GDBSTUB_IMMEDIATE
1831         unsigned char ch;
1832         int ret;
1833 #endif
1834
1835         gdbstub_busy = 1;
1836
1837         printk(KERN_INFO "%s", gdbstub_banner);
1838
1839         gdbstub_io_init();
1840
1841         gdbstub_entry("--> gdbstub_init\n");
1842
1843         /* try to talk to GDB (or anyone insane enough to want to type GDB
1844          * protocol by hand) */
1845         gdbstub_io("### GDB Tx ACK\n");
1846         gdbstub_io_tx_char('+'); /* 'hello world' */
1847
1848 #ifdef CONFIG_GDBSTUB_IMMEDIATE
1849         gdbstub_printk("GDB Stub waiting for packet\n");
1850
1851         /* in case GDB is started before us, ACK any packets that are already
1852          * sitting there (presumably "$?#xx")
1853          */
1854         do { gdbstub_io_rx_char(&ch, 0); } while (ch != '$');
1855         do { gdbstub_io_rx_char(&ch, 0); } while (ch != '#');
1856         /* eat first csum byte */
1857         do { ret = gdbstub_io_rx_char(&ch, 0); } while (ret != 0);
1858         /* eat second csum byte */
1859         do { ret = gdbstub_io_rx_char(&ch, 0); } while (ret != 0);
1860
1861         gdbstub_io("### GDB Tx NAK\n");
1862         gdbstub_io_tx_char('-'); /* NAK it */
1863
1864 #else
1865         printk("GDB Stub ready\n");
1866 #endif
1867
1868         gdbstub_busy = 0;
1869         gdbstub_entry("<-- gdbstub_init\n");
1870 }
1871
1872 /*
1873  * register the console at a more appropriate time
1874  */
1875 #ifdef CONFIG_GDBSTUB_CONSOLE
1876 static int __init gdbstub_postinit(void)
1877 {
1878         printk(KERN_NOTICE "registering console\n");
1879         register_console(&gdbstub_console);
1880         return 0;
1881 }
1882
1883 __initcall(gdbstub_postinit);
1884 #endif
1885
1886 /*
1887  * handle character reception on GDB serial port
1888  * - jump into the GDB stub if BREAK is detected on the serial line
1889  */
1890 asmlinkage void gdbstub_rx_irq(struct pt_regs *regs, enum exception_code excep)
1891 {
1892         char ch;
1893         int ret;
1894
1895         gdbstub_entry("--> gdbstub_rx_irq\n");
1896
1897         do {
1898                 ret = gdbstub_io_rx_char(&ch, 1);
1899                 if (ret != -EIO && ret != -EAGAIN) {
1900                         if (ret != -EINTR)
1901                                 gdbstub_rx_unget = ch;
1902                         gdbstub(regs, excep);
1903                 }
1904         } while (ret != -EAGAIN);
1905
1906         gdbstub_entry("<-- gdbstub_rx_irq\n");
1907 }