arch/sparc/kernel/ptrace.c

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