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   1 /* ptrace.c: Sparc process tracing support.
   2  *
   3  * Copyright (C) 1996 David S. Miller (davem@caipfs.rutgers.edu)
   4  *
   5  * Based upon code written by Ross Biro, Linus Torvalds, Bob Manson,
   6  * and David Mosberger.
   7  *
   8  * Added Linux support -miguel (weird, eh?, the orignal code was meant
   9  * to emulate SunOS).
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/mm.h>
  15 #include <linux/errno.h>
  16 #include <linux/ptrace.h>
  17 #include <linux/user.h>
  18 #include <linux/smp.h>
  19 #include <linux/smp_lock.h>
  20 #include <linux/security.h>
  21
  22 #include <asm/pgtable.h>
  23 #include <asm/system.h>
  24 #include <asm/uaccess.h>
  25
  26 #define MAGIC_CONSTANT 0x80000000
  27
  28
  29 /* Returning from ptrace is a bit tricky because the syscall return
  30  * low level code assumes any value returned which is negative and
  31  * is a valid errno will mean setting the condition codes to indicate
  32  * an error return.  This doesn't work, so we have this hook.
  33  */
  34 static inline void pt_error_return(struct pt_regs *regs, unsigned long error)
  35 {
  36         regs->u_regs[UREG_I0] = error;
  37         regs->psr |= PSR_C;
  38         regs->pc = regs->npc;
  39         regs->npc += 4;
  40 }
  41
  42 static inline void pt_succ_return(struct pt_regs *regs, unsigned long value)
  43 {
  44         regs->u_regs[UREG_I0] = value;
  45         regs->psr &= ~PSR_C;
  46         regs->pc = regs->npc;
  47         regs->npc += 4;
  48 }
  49
  50 static void
  51 pt_succ_return_linux(struct pt_regs *regs, unsigned long value, long __user *addr)
  52 {
  53         if (put_user(value, addr)) {
  54                 pt_error_return(regs, EFAULT);
  55                 return;
  56         }
  57         regs->u_regs[UREG_I0] = 0;
  58         regs->psr &= ~PSR_C;
  59         regs->pc = regs->npc;
  60         regs->npc += 4;
  61 }
  62
  63 static void
  64 pt_os_succ_return (struct pt_regs *regs, unsigned long val, long __user *addr)
  65 {
  66         if (current->personality == PER_SUNOS)
  67                 pt_succ_return (regs, val);
  68         else
  69                 pt_succ_return_linux (regs, val, addr);
  70 }
  71
  72 /* Fuck me gently with a chainsaw... */
  73 static inline void read_sunos_user(struct pt_regs *regs, unsigned long offset,
  74                                    struct task_struct *tsk, long __user *addr)
  75 {
  76         struct pt_regs *cregs = tsk->thread.kregs;
  77         struct thread_info *t = tsk->thread_info;
  78         int v;
  79
  80         if(offset >= 1024)
  81                 offset -= 1024; /* whee... */
  82         if(offset & ((sizeof(unsigned long) - 1))) {
  83                 pt_error_return(regs, EIO);
  84                 return;
  85         }
  86         if(offset >= 16 && offset < 784) {
  87                 offset -= 16; offset >>= 2;
  88                 pt_os_succ_return(regs, *(((unsigned long *)(&t->reg_window[0]))+offset), addr);
  89                 return;
  90         }
  91         if(offset >= 784 && offset < 832) {
  92                 offset -= 784; offset >>= 2;
  93                 pt_os_succ_return(regs, *(((unsigned long *)(&t->rwbuf_stkptrs[0]))+offset), addr);
  94                 return;
  95         }
  96         switch(offset) {
  97         case 0:
  98                 v = t->ksp;
  99                 break;
 100         case 4:
 101                 v = t->kpc;
 102                 break;
 103         case 8:
 104                 v = t->kpsr;
 105                 break;
 106         case 12:
 107                 v = t->uwinmask;
 108                 break;
 109         case 832:
 110                 v = t->w_saved;
 111                 break;
 112         case 896:
 113                 v = cregs->u_regs[UREG_I0];
 114                 break;
 115         case 900:
 116                 v = cregs->u_regs[UREG_I1];
 117                 break;
 118         case 904:
 119                 v = cregs->u_regs[UREG_I2];
 120                 break;
 121         case 908:
 122                 v = cregs->u_regs[UREG_I3];
 123                 break;
 124         case 912:
 125                 v = cregs->u_regs[UREG_I4];
 126                 break;
 127         case 916:
 128                 v = cregs->u_regs[UREG_I5];
 129                 break;
 130         case 920:
 131                 v = cregs->u_regs[UREG_I6];
 132                 break;
 133         case 924:
 134                 if(tsk->thread.flags & MAGIC_CONSTANT)
 135                         v = cregs->u_regs[UREG_G1];
 136                 else
 137                         v = 0;
 138                 break;
 139         case 940:
 140                 v = cregs->u_regs[UREG_I0];
 141                 break;
 142         case 944:
 143                 v = cregs->u_regs[UREG_I1];
 144                 break;
 145
 146         case 948:
 147                 /* Isn't binary compatibility _fun_??? */
 148                 if(cregs->psr & PSR_C)
 149                         v = cregs->u_regs[UREG_I0] << 24;
 150                 else
 151                         v = 0;
 152                 break;
 153
 154                 /* Rest of them are completely unsupported. */
 155         default:
 156                 printk("%s [%d]: Wants to read user offset %ld\n",
 157                        current->comm, current->pid, offset);
 158                 pt_error_return(regs, EIO);
 159                 return;
 160         }
 161         if (current->personality == PER_SUNOS)
 162                 pt_succ_return (regs, v);
 163         else
 164                 pt_succ_return_linux (regs, v, addr);
 165         return;
 166 }
 167
 168 static inline void write_sunos_user(struct pt_regs *regs, unsigned long offset,
 169                                     struct task_struct *tsk)
 170 {
 171         struct pt_regs *cregs = tsk->thread.kregs;
 172         struct thread_info *t = tsk->thread_info;
 173         unsigned long value = regs->u_regs[UREG_I3];
 174
 175         if(offset >= 1024)
 176                 offset -= 1024; /* whee... */
 177         if(offset & ((sizeof(unsigned long) - 1)))
 178                 goto failure;
 179         if(offset >= 16 && offset < 784) {
 180                 offset -= 16; offset >>= 2;
 181                 *(((unsigned long *)(&t->reg_window[0]))+offset) = value;
 182                 goto success;
 183         }
 184         if(offset >= 784 && offset < 832) {
 185                 offset -= 784; offset >>= 2;
 186                 *(((unsigned long *)(&t->rwbuf_stkptrs[0]))+offset) = value;
 187                 goto success;
 188         }
 189         switch(offset) {
 190         case 896:
 191                 cregs->u_regs[UREG_I0] = value;
 192                 break;
 193         case 900:
 194                 cregs->u_regs[UREG_I1] = value;
 195                 break;
 196         case 904:
 197                 cregs->u_regs[UREG_I2] = value;
 198                 break;
 199         case 908:
 200                 cregs->u_regs[UREG_I3] = value;
 201                 break;
 202         case 912:
 203                 cregs->u_regs[UREG_I4] = value;
 204                 break;
 205         case 916:
 206                 cregs->u_regs[UREG_I5] = value;
 207                 break;
 208         case 920:
 209                 cregs->u_regs[UREG_I6] = value;
 210                 break;
 211         case 924:
 212                 cregs->u_regs[UREG_I7] = value;
 213                 break;
 214         case 940:
 215                 cregs->u_regs[UREG_I0] = value;
 216                 break;
 217         case 944:
 218                 cregs->u_regs[UREG_I1] = value;
 219                 break;
 220
 221                 /* Rest of them are completely unsupported or "no-touch". */
 222         default:
 223                 printk("%s [%d]: Wants to write user offset %ld\n",
 224                        current->comm, current->pid, offset);
 225                 goto failure;
 226         }
 227 success:
 228         pt_succ_return(regs, 0);
 229         return;
 230 failure:
 231         pt_error_return(regs, EIO);
 232         return;
 233 }
 234
 235 /* #define ALLOW_INIT_TRACING */
 236 /* #define DEBUG_PTRACE */
 237
 238 #ifdef DEBUG_PTRACE
 239 char *pt_rq [] = {
 240         /* 0  */ "TRACEME", "PEEKTEXT", "PEEKDATA", "PEEKUSR",
 241         /* 4  */ "POKETEXT", "POKEDATA", "POKEUSR", "CONT",
 242         /* 8  */ "KILL", "SINGLESTEP", "SUNATTACH", "SUNDETACH",
 243         /* 12 */ "GETREGS", "SETREGS", "GETFPREGS", "SETFPREGS",
 244         /* 16 */ "READDATA", "WRITEDATA", "READTEXT", "WRITETEXT",
 245         /* 20 */ "GETFPAREGS", "SETFPAREGS", "unknown", "unknown",
 246         /* 24 */ "SYSCALL", ""
 247 };
 248 #endif
 249
 250 /*
 251  * Called by kernel/ptrace.c when detaching..
 252  *
 253  * Make sure single step bits etc are not set.
 254  */
 255 void ptrace_disable(struct task_struct *child)
 256 {
 257         /* nothing to do */
 258 }
 259
 260 asmlinkage void do_ptrace(struct pt_regs *regs)
 261 {
 262         unsigned long request = regs->u_regs[UREG_I0];
 263         unsigned long pid = regs->u_regs[UREG_I1];
 264         unsigned long addr = regs->u_regs[UREG_I2];
 265         unsigned long data = regs->u_regs[UREG_I3];
 266         unsigned long addr2 = regs->u_regs[UREG_I4];
 267         struct task_struct *child;
 268         int ret;
 269
 270         lock_kernel();
 271 #ifdef DEBUG_PTRACE
 272         {
 273                 char *s;
 274
 275                 if ((request >= 0) && (request <= 24))
 276                         s = pt_rq [request];
 277                 else
 278                         s = "unknown";
 279
 280                 if (request == PTRACE_POKEDATA && data == 0x91d02001){
 281                         printk ("do_ptrace: breakpoint pid=%d, addr=%08lx addr2=%08lx\n",
 282                                 pid, addr, addr2);
 283                 } else
 284                         printk("do_ptrace: rq=%s(%d) pid=%d addr=%08lx data=%08lx addr2=%08lx\n",
 285                                s, (int) request, (int) pid, addr, data, addr2);
 286         }
 287 #endif
 288         if (request == PTRACE_TRACEME) {
 289                 int my_ret;
 290
 291                 /* are we already being traced? */
 292                 if (current->ptrace & PT_PTRACED) {
 293                         pt_error_return(regs, EPERM);
 294                         goto out;
 295                 }
 296                 my_ret = security_ptrace(current->parent, current);
 297                 if (my_ret) {
 298                         pt_error_return(regs, -my_ret);
 299                         goto out;
 300                 }
 301
 302                 /* set the ptrace bit in the process flags. */
 303                 current->ptrace |= PT_PTRACED;
 304                 pt_succ_return(regs, 0);
 305                 goto out;
 306         }
 307 #ifndef ALLOW_INIT_TRACING
 308         if (pid == 1) {
 309                 /* Can't dork with init. */
 310                 pt_error_return(regs, EPERM);
 311                 goto out;
 312         }
 313 #endif
 314         read_lock(&tasklist_lock);
 315         child = find_task_by_pid(pid);
 316         if (child)
 317                 get_task_struct(child);
 318         read_unlock(&tasklist_lock);
 319
 320         if (!child) {
 321                 pt_error_return(regs, ESRCH);
 322                 goto out;
 323         }
 324
 325         if ((current->personality == PER_SUNOS && request == PTRACE_SUNATTACH)
 326             || (current->personality != PER_SUNOS && request == PTRACE_ATTACH)) {
 327                 if (ptrace_attach(child)) {
 328                         pt_error_return(regs, EPERM);
 329                         goto out_tsk;
 330                 }
 331                 pt_succ_return(regs, 0);
 332                 goto out_tsk;
 333         }
 334
 335         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 336         if (ret < 0) {
 337                 pt_error_return(regs, -ret);
 338                 goto out_tsk;
 339         }
 340
 341         switch(request) {
 342         case PTRACE_PEEKTEXT: /* read word at location addr. */
 343         case PTRACE_PEEKDATA: {
 344                 unsigned long tmp;
 345
 346                 if (access_process_vm(child, addr,
 347                                       &tmp, sizeof(tmp), 0) == sizeof(tmp))
 348                         pt_os_succ_return(regs, tmp, (long __user *)data);
 349                 else
 350                         pt_error_return(regs, EIO);
 351                 goto out_tsk;
 352         }
 353
 354         case PTRACE_PEEKUSR:
 355                 read_sunos_user(regs, addr, child, (long __user *) data);
 356                 goto out_tsk;
 357
 358         case PTRACE_POKEUSR:
 359                 write_sunos_user(regs, addr, child);
 360                 goto out_tsk;
 361
 362         case PTRACE_POKETEXT: /* write the word at location addr. */
 363         case PTRACE_POKEDATA: {
 364                 if (access_process_vm(child, addr,
 365                                       &data, sizeof(data), 1) == sizeof(data))
 366                         pt_succ_return(regs, 0);
 367                 else
 368                         pt_error_return(regs, EIO);
 369                 goto out_tsk;
 370         }
 371
 372         case PTRACE_GETREGS: {
 373                 struct pt_regs __user *pregs = (struct pt_regs __user *) addr;
 374                 struct pt_regs *cregs = child->thread.kregs;
 375                 int rval;
 376
 377                 if (!access_ok(VERIFY_WRITE, pregs, sizeof(struct pt_regs))) {
 378                         rval = -EFAULT;
 379                         pt_error_return(regs, -rval);
 380                         goto out_tsk;
 381                 }
 382                 __put_user(cregs->psr, (&pregs->psr));
 383                 __put_user(cregs->pc, (&pregs->pc));
 384                 __put_user(cregs->npc, (&pregs->npc));
 385                 __put_user(cregs->y, (&pregs->y));
 386                 for(rval = 1; rval < 16; rval++)
 387                         __put_user(cregs->u_regs[rval], (&pregs->u_regs[rval - 1]));
 388                 pt_succ_return(regs, 0);
 389 #ifdef DEBUG_PTRACE
 390                 printk ("PC=%x nPC=%x o7=%x\n", cregs->pc, cregs->npc, cregs->u_regs [15]);
 391 #endif
 392                 goto out_tsk;
 393         }
 394
 395         case PTRACE_SETREGS: {
 396                 struct pt_regs __user *pregs = (struct pt_regs __user *) addr;
 397                 struct pt_regs *cregs = child->thread.kregs;
 398                 unsigned long psr, pc, npc, y;
 399                 int i;
 400
 401                 /* Must be careful, tracing process can only set certain
 402                  * bits in the psr.
 403                  */
 404                 if (!access_ok(VERIFY_READ, pregs, sizeof(struct pt_regs))) {
 405                         pt_error_return(regs, EFAULT);
 406                         goto out_tsk;
 407                 }
 408                 __get_user(psr, (&pregs->psr));
 409                 __get_user(pc, (&pregs->pc));
 410                 __get_user(npc, (&pregs->npc));
 411                 __get_user(y, (&pregs->y));
 412                 psr &= PSR_ICC;
 413                 cregs->psr &= ~PSR_ICC;
 414                 cregs->psr |= psr;
 415                 if (!((pc | npc) & 3)) {
 416                         cregs->pc = pc;
 417                         cregs->npc =npc;
 418                 }
 419                 cregs->y = y;
 420                 for(i = 1; i < 16; i++)
 421                         __get_user(cregs->u_regs[i], (&pregs->u_regs[i-1]));
 422                 pt_succ_return(regs, 0);
 423                 goto out_tsk;
 424         }
 425
 426         case PTRACE_GETFPREGS: {
 427                 struct fps {
 428                         unsigned long regs[32];
 429                         unsigned long fsr;
 430                         unsigned long flags;
 431                         unsigned long extra;
 432                         unsigned long fpqd;
 433                         struct fq {
 434                                 unsigned long *insnaddr;
 435                                 unsigned long insn;
 436                         } fpq[16];
 437                 };
 438                 struct fps __user *fps = (struct fps __user *) addr;
 439                 int i;
 440
 441                 if (!access_ok(VERIFY_WRITE, fps, sizeof(struct fps))) {
 442                         i = -EFAULT;
 443                         pt_error_return(regs, -i);
 444                         goto out_tsk;
 445                 }
 446                 for(i = 0; i < 32; i++)
 447                         __put_user(child->thread.float_regs[i], (&fps->regs[i]));
 448                 __put_user(child->thread.fsr, (&fps->fsr));
 449                 __put_user(child->thread.fpqdepth, (&fps->fpqd));
 450                 __put_user(0, (&fps->flags));
 451                 __put_user(0, (&fps->extra));
 452                 for(i = 0; i < 16; i++) {
 453                         __put_user(child->thread.fpqueue[i].insn_addr,
 454                                    (&fps->fpq[i].insnaddr));
 455                         __put_user(child->thread.fpqueue[i].insn, (&fps->fpq[i].insn));
 456                 }
 457                 pt_succ_return(regs, 0);
 458                 goto out_tsk;
 459         }
 460
 461         case PTRACE_SETFPREGS: {
 462                 struct fps {
 463                         unsigned long regs[32];
 464                         unsigned long fsr;
 465                         unsigned long flags;
 466                         unsigned long extra;
 467                         unsigned long fpqd;
 468                         struct fq {
 469                                 unsigned long *insnaddr;
 470                                 unsigned long insn;
 471                         } fpq[16];
 472                 };
 473                 struct fps __user *fps = (struct fps __user *) addr;
 474                 int i;
 475
 476                 if (!access_ok(VERIFY_READ, fps, sizeof(struct fps))) {
 477                         i = -EFAULT;
 478                         pt_error_return(regs, -i);
 479                         goto out_tsk;
 480                 }
 481                 copy_from_user(&child->thread.float_regs[0], &fps->regs[0], (32 * sizeof(unsigned long)));
 482                 __get_user(child->thread.fsr, (&fps->fsr));
 483                 __get_user(child->thread.fpqdepth, (&fps->fpqd));
 484                 for(i = 0; i < 16; i++) {
 485                         __get_user(child->thread.fpqueue[i].insn_addr,
 486                                    (&fps->fpq[i].insnaddr));
 487                         __get_user(child->thread.fpqueue[i].insn, (&fps->fpq[i].insn));
 488                 }
 489                 pt_succ_return(regs, 0);
 490                 goto out_tsk;
 491         }
 492
 493         case PTRACE_READTEXT:
 494         case PTRACE_READDATA: {
 495                 int res = ptrace_readdata(child, addr,
 496                                           (void __user *) addr2, data);
 497
 498                 if (res == data) {
 499                         pt_succ_return(regs, 0);
 500                         goto out_tsk;
 501                 }
 502                 /* Partial read is an IO failure */
 503                 if (res >= 0)
 504                         res = -EIO;
 505                 pt_error_return(regs, -res);
 506                 goto out_tsk;
 507         }
 508
 509         case PTRACE_WRITETEXT:
 510         case PTRACE_WRITEDATA: {
 511                 int res = ptrace_writedata(child, (void __user *) addr2,
 512                                            addr, data);
 513
 514                 if (res == data) {
 515                         pt_succ_return(regs, 0);
 516                         goto out_tsk;
 517                 }
 518                 /* Partial write is an IO failure */
 519                 if (res >= 0)
 520                         res = -EIO;
 521                 pt_error_return(regs, -res);
 522                 goto out_tsk;
 523         }
 524
 525         case PTRACE_SYSCALL: /* continue and stop at (return from) syscall */
 526                 addr = 1;
 527
 528         case PTRACE_CONT: { /* restart after signal. */
 529                 if (data > _NSIG) {
 530                         pt_error_return(regs, EIO);
 531                         goto out_tsk;
 532                 }
 533                 if (addr != 1) {
 534                         if (addr & 3) {
 535                                 pt_error_return(regs, EINVAL);
 536                                 goto out_tsk;
 537                         }
 538 #ifdef DEBUG_PTRACE
 539                         printk ("Original: %08lx %08lx\n", child->thread.kregs->pc, child->thread.kregs->npc);
 540                         printk ("Continuing with %08lx %08lx\n", addr, addr+4);
 541 #endif
 542                         child->thread.kregs->pc = addr;
 543                         child->thread.kregs->npc = addr + 4;
 544                 }
 545
 546                 if (request == PTRACE_SYSCALL)
 547                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 548                 else
 549                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 550
 551                 child->exit_code = data;
 552 #ifdef DEBUG_PTRACE
 553                 printk("CONT: %s [%d]: set exit_code = %x %lx %lx\n",
 554                         child->comm, child->pid, child->exit_code,
 555                         child->thread.kregs->pc,
 556                         child->thread.kregs->npc);
 557 #endif
 558                 wake_up_process(child);
 559                 pt_succ_return(regs, 0);
 560                 goto out_tsk;
 561         }
 562
 563 /*
 564  * make the child exit.  Best I can do is send it a sigkill.
 565  * perhaps it should be put in the status that it wants to
 566  * exit.
 567  */
 568         case PTRACE_KILL: {
 569                 if (child->exit_state == EXIT_ZOMBIE) { /* already dead */
 570                         pt_succ_return(regs, 0);
 571                         goto out_tsk;
 572                 }
 573                 wake_up_process(child);
 574                 child->exit_code = SIGKILL;
 575                 pt_succ_return(regs, 0);
 576                 goto out_tsk;
 577         }
 578
 579         case PTRACE_SUNDETACH: { /* detach a process that was attached. */
 580                 int err = ptrace_detach(child, data);
 581                 if (err) {
 582                         pt_error_return(regs, EIO);
 583                         goto out_tsk;
 584                 }
 585                 pt_succ_return(regs, 0);
 586                 goto out_tsk;
 587         }
 588
 589         /* PTRACE_DUMPCORE unsupported... */
 590
 591         default: {
 592                 int err = ptrace_request(child, request, addr, data);
 593                 if (err)
 594                         pt_error_return(regs, -err);
 595                 else
 596                         pt_succ_return(regs, 0);
 597                 goto out_tsk;
 598         }
 599         }
 600 out_tsk:
 601         if (child)
 602                 put_task_struct(child);
 603 out:
 604         unlock_kernel();
 605 }
 606
 607 asmlinkage void syscall_trace(void)
 608 {
 609 #ifdef DEBUG_PTRACE
 610         printk("%s [%d]: syscall_trace\n", current->comm, current->pid);
 611 #endif
 612         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 613                 return;
 614         if (!(current->ptrace & PT_PTRACED))
 615                 return;
 616         current->thread.flags ^= MAGIC_CONSTANT;
 617         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 618                                  ? 0x80 : 0));
 619         /*
 620          * this isn't the same as continuing with a signal, but it will do
 621          * for normal use.  strace only continues with a signal if the
 622          * stopping signal is not SIGTRAP.  -brl
 623          */
 624 #ifdef DEBUG_PTRACE
 625         printk("%s [%d]: syscall_trace exit= %x\n", current->comm,
 626                 current->pid, current->exit_code);
 627 #endif
 628         if (current->exit_code) {
 629                 send_sig (current->exit_code, current, 1);
 630                 current->exit_code = 0;
 631         }
 632 }