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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 = task_thread_info(tsk);
  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 = task_thread_info(tsk);
 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
 290         if (request == PTRACE_TRACEME) {
 291                 ret = ptrace_traceme();
 292                 if (ret < 0)
 293                         pt_error_return(regs, -ret);
 294                 else
 295                         pt_succ_return(regs, 0);
 296                 goto out;
 297         }
 298
 299         child = ptrace_get_task_struct(pid);
 300         if (IS_ERR(child)) {
 301                 ret = PTR_ERR(child);
 302                 pt_error_return(regs, -ret);
 303                 goto out;
 304         }
 305
 306         if ((current->personality == PER_SUNOS && request == PTRACE_SUNATTACH)
 307             || (current->personality != PER_SUNOS && request == PTRACE_ATTACH)) {
 308                 if (ptrace_attach(child)) {
 309                         pt_error_return(regs, EPERM);
 310                         goto out_tsk;
 311                 }
 312                 pt_succ_return(regs, 0);
 313                 goto out_tsk;
 314         }
 315
 316         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 317         if (ret < 0) {
 318                 pt_error_return(regs, -ret);
 319                 goto out_tsk;
 320         }
 321
 322         switch(request) {
 323         case PTRACE_PEEKTEXT: /* read word at location addr. */
 324         case PTRACE_PEEKDATA: {
 325                 unsigned long tmp;
 326
 327                 if (access_process_vm(child, addr,
 328                                       &tmp, sizeof(tmp), 0) == sizeof(tmp))
 329                         pt_os_succ_return(regs, tmp, (long __user *)data);
 330                 else
 331                         pt_error_return(regs, EIO);
 332                 goto out_tsk;
 333         }
 334
 335         case PTRACE_PEEKUSR:
 336                 read_sunos_user(regs, addr, child, (long __user *) data);
 337                 goto out_tsk;
 338
 339         case PTRACE_POKEUSR:
 340                 write_sunos_user(regs, addr, child);
 341                 goto out_tsk;
 342
 343         case PTRACE_POKETEXT: /* write the word at location addr. */
 344         case PTRACE_POKEDATA: {
 345                 if (access_process_vm(child, addr,
 346                                       &data, sizeof(data), 1) == sizeof(data))
 347                         pt_succ_return(regs, 0);
 348                 else
 349                         pt_error_return(regs, EIO);
 350                 goto out_tsk;
 351         }
 352
 353         case PTRACE_GETREGS: {
 354                 struct pt_regs __user *pregs = (struct pt_regs __user *) addr;
 355                 struct pt_regs *cregs = child->thread.kregs;
 356                 int rval;
 357
 358                 if (!access_ok(VERIFY_WRITE, pregs, sizeof(struct pt_regs))) {
 359                         rval = -EFAULT;
 360                         pt_error_return(regs, -rval);
 361                         goto out_tsk;
 362                 }
 363                 __put_user(cregs->psr, (&pregs->psr));
 364                 __put_user(cregs->pc, (&pregs->pc));
 365                 __put_user(cregs->npc, (&pregs->npc));
 366                 __put_user(cregs->y, (&pregs->y));
 367                 for(rval = 1; rval < 16; rval++)
 368                         __put_user(cregs->u_regs[rval], (&pregs->u_regs[rval - 1]));
 369                 pt_succ_return(regs, 0);
 370 #ifdef DEBUG_PTRACE
 371                 printk ("PC=%x nPC=%x o7=%x\n", cregs->pc, cregs->npc, cregs->u_regs [15]);
 372 #endif
 373                 goto out_tsk;
 374         }
 375
 376         case PTRACE_SETREGS: {
 377                 struct pt_regs __user *pregs = (struct pt_regs __user *) addr;
 378                 struct pt_regs *cregs = child->thread.kregs;
 379                 unsigned long psr, pc, npc, y;
 380                 int i;
 381
 382                 /* Must be careful, tracing process can only set certain
 383                  * bits in the psr.
 384                  */
 385                 if (!access_ok(VERIFY_READ, pregs, sizeof(struct pt_regs))) {
 386                         pt_error_return(regs, EFAULT);
 387                         goto out_tsk;
 388                 }
 389                 __get_user(psr, (&pregs->psr));
 390                 __get_user(pc, (&pregs->pc));
 391                 __get_user(npc, (&pregs->npc));
 392                 __get_user(y, (&pregs->y));
 393                 psr &= PSR_ICC;
 394                 cregs->psr &= ~PSR_ICC;
 395                 cregs->psr |= psr;
 396                 if (!((pc | npc) & 3)) {
 397                         cregs->pc = pc;
 398                         cregs->npc =npc;
 399                 }
 400                 cregs->y = y;
 401                 for(i = 1; i < 16; i++)
 402                         __get_user(cregs->u_regs[i], (&pregs->u_regs[i-1]));
 403                 pt_succ_return(regs, 0);
 404                 goto out_tsk;
 405         }
 406
 407         case PTRACE_GETFPREGS: {
 408                 struct fps {
 409                         unsigned long regs[32];
 410                         unsigned long fsr;
 411                         unsigned long flags;
 412                         unsigned long extra;
 413                         unsigned long fpqd;
 414                         struct fq {
 415                                 unsigned long *insnaddr;
 416                                 unsigned long insn;
 417                         } fpq[16];
 418                 };
 419                 struct fps __user *fps = (struct fps __user *) addr;
 420                 int i;
 421
 422                 if (!access_ok(VERIFY_WRITE, fps, sizeof(struct fps))) {
 423                         i = -EFAULT;
 424                         pt_error_return(regs, -i);
 425                         goto out_tsk;
 426                 }
 427                 for(i = 0; i < 32; i++)
 428                         __put_user(child->thread.float_regs[i], (&fps->regs[i]));
 429                 __put_user(child->thread.fsr, (&fps->fsr));
 430                 __put_user(child->thread.fpqdepth, (&fps->fpqd));
 431                 __put_user(0, (&fps->flags));
 432                 __put_user(0, (&fps->extra));
 433                 for(i = 0; i < 16; i++) {
 434                         __put_user(child->thread.fpqueue[i].insn_addr,
 435                                    (&fps->fpq[i].insnaddr));
 436                         __put_user(child->thread.fpqueue[i].insn, (&fps->fpq[i].insn));
 437                 }
 438                 pt_succ_return(regs, 0);
 439                 goto out_tsk;
 440         }
 441
 442         case PTRACE_SETFPREGS: {
 443                 struct fps {
 444                         unsigned long regs[32];
 445                         unsigned long fsr;
 446                         unsigned long flags;
 447                         unsigned long extra;
 448                         unsigned long fpqd;
 449                         struct fq {
 450                                 unsigned long *insnaddr;
 451                                 unsigned long insn;
 452                         } fpq[16];
 453                 };
 454                 struct fps __user *fps = (struct fps __user *) addr;
 455                 int i;
 456
 457                 if (!access_ok(VERIFY_READ, fps, sizeof(struct fps))) {
 458                         i = -EFAULT;
 459                         pt_error_return(regs, -i);
 460                         goto out_tsk;
 461                 }
 462                 copy_from_user(&child->thread.float_regs[0], &fps->regs[0], (32 * sizeof(unsigned long)));
 463                 __get_user(child->thread.fsr, (&fps->fsr));
 464                 __get_user(child->thread.fpqdepth, (&fps->fpqd));
 465                 for(i = 0; i < 16; i++) {
 466                         __get_user(child->thread.fpqueue[i].insn_addr,
 467                                    (&fps->fpq[i].insnaddr));
 468                         __get_user(child->thread.fpqueue[i].insn, (&fps->fpq[i].insn));
 469                 }
 470                 pt_succ_return(regs, 0);
 471                 goto out_tsk;
 472         }
 473
 474         case PTRACE_READTEXT:
 475         case PTRACE_READDATA: {
 476                 int res = ptrace_readdata(child, addr,
 477                                           (void __user *) addr2, data);
 478
 479                 if (res == data) {
 480                         pt_succ_return(regs, 0);
 481                         goto out_tsk;
 482                 }
 483                 /* Partial read is an IO failure */
 484                 if (res >= 0)
 485                         res = -EIO;
 486                 pt_error_return(regs, -res);
 487                 goto out_tsk;
 488         }
 489
 490         case PTRACE_WRITETEXT:
 491         case PTRACE_WRITEDATA: {
 492                 int res = ptrace_writedata(child, (void __user *) addr2,
 493                                            addr, data);
 494
 495                 if (res == data) {
 496                         pt_succ_return(regs, 0);
 497                         goto out_tsk;
 498                 }
 499                 /* Partial write is an IO failure */
 500                 if (res >= 0)
 501                         res = -EIO;
 502                 pt_error_return(regs, -res);
 503                 goto out_tsk;
 504         }
 505
 506         case PTRACE_SYSCALL: /* continue and stop at (return from) syscall */
 507                 addr = 1;
 508
 509         case PTRACE_CONT: { /* restart after signal. */
 510                 if (!valid_signal(data)) {
 511                         pt_error_return(regs, EIO);
 512                         goto out_tsk;
 513                 }
 514
 515                 if (request == PTRACE_SYSCALL)
 516                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 517                 else
 518                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 519
 520                 child->exit_code = data;
 521 #ifdef DEBUG_PTRACE
 522                 printk("CONT: %s [%d]: set exit_code = %x %lx %lx\n",
 523                         child->comm, child->pid, child->exit_code,
 524                         child->thread.kregs->pc,
 525                         child->thread.kregs->npc);
 526 #endif
 527                 wake_up_process(child);
 528                 pt_succ_return(regs, 0);
 529                 goto out_tsk;
 530         }
 531
 532 /*
 533  * make the child exit.  Best I can do is send it a sigkill.
 534  * perhaps it should be put in the status that it wants to
 535  * exit.
 536  */
 537         case PTRACE_KILL: {
 538                 if (child->exit_state == EXIT_ZOMBIE) { /* already dead */
 539                         pt_succ_return(regs, 0);
 540                         goto out_tsk;
 541                 }
 542                 wake_up_process(child);
 543                 child->exit_code = SIGKILL;
 544                 pt_succ_return(regs, 0);
 545                 goto out_tsk;
 546         }
 547
 548         case PTRACE_SUNDETACH: { /* detach a process that was attached. */
 549                 int err = ptrace_detach(child, data);
 550                 if (err) {
 551                         pt_error_return(regs, EIO);
 552                         goto out_tsk;
 553                 }
 554                 pt_succ_return(regs, 0);
 555                 goto out_tsk;
 556         }
 557
 558         /* PTRACE_DUMPCORE unsupported... */
 559
 560         default: {
 561                 int err = ptrace_request(child, request, addr, data);
 562                 if (err)
 563                         pt_error_return(regs, -err);
 564                 else
 565                         pt_succ_return(regs, 0);
 566                 goto out_tsk;
 567         }
 568         }
 569 out_tsk:
 570         if (child)
 571                 put_task_struct(child);
 572 out:
 573         unlock_kernel();
 574 }
 575
 576 asmlinkage void syscall_trace(void)
 577 {
 578 #ifdef DEBUG_PTRACE
 579         printk("%s [%d]: syscall_trace\n", current->comm, current->pid);
 580 #endif
 581         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 582                 return;
 583         if (!(current->ptrace & PT_PTRACED))
 584                 return;
 585         current->thread.flags ^= MAGIC_CONSTANT;
 586         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 587                                  ? 0x80 : 0));
 588         /*
 589          * this isn't the same as continuing with a signal, but it will do
 590          * for normal use.  strace only continues with a signal if the
 591          * stopping signal is not SIGTRAP.  -brl
 592          */
 593 #ifdef DEBUG_PTRACE
 594         printk("%s [%d]: syscall_trace exit= %x\n", current->comm,
 595                 current->pid, current->exit_code);
 596 #endif
 597         if (current->exit_code) {
 598                 send_sig (current->exit_code, current, 1);
 599                 current->exit_code = 0;
 600         }
 601 }