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