arch/powerpc/kernel/ptrace.c

   1 /*
   2  *  PowerPC version
   3  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   4  *
   5  *  Derived from "arch/m68k/kernel/ptrace.c"
   6  *  Copyright (C) 1994 by Hamish Macdonald
   7  *  Taken from linux/kernel/ptrace.c and modified for M680x0.
   8  *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
   9  *
  10  * Modified by Cort Dougan (cort@hq.fsmlabs.com)
  11  * and Paul Mackerras (paulus@samba.org).
  12  *
  13  * This file is subject to the terms and conditions of the GNU General
  14  * Public License.  See the file README.legal in the main directory of
  15  * this archive for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/sched.h>
  20 #include <linux/mm.h>
  21 #include <linux/smp.h>
  22 #include <linux/errno.h>
  23 #include <linux/ptrace.h>
  24 #include <linux/user.h>
  25 #include <linux/security.h>
  26 #include <linux/signal.h>
  27 #include <linux/seccomp.h>
  28 #include <linux/audit.h>
  29 #ifdef CONFIG_PPC32
  30 #include <linux/module.h>
  31 #endif
  32
  33 #include <asm/uaccess.h>
  34 #include <asm/page.h>
  35 #include <asm/pgtable.h>
  36 #include <asm/system.h>
  37
  38 /*
  39  * does not yet catch signals sent when the child dies.
  40  * in exit.c or in signal.c.
  41  */
  42
  43 /*
  44  * Set of msr bits that gdb can change on behalf of a process.
  45  */
  46 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
  47 #define MSR_DEBUGCHANGE 0
  48 #else
  49 #define MSR_DEBUGCHANGE (MSR_SE | MSR_BE)
  50 #endif
  51
  52 /*
  53  * Max register writeable via put_reg
  54  */
  55 #ifdef CONFIG_PPC32
  56 #define PT_MAX_PUT_REG  PT_MQ
  57 #else
  58 #define PT_MAX_PUT_REG  PT_CCR
  59 #endif
  60
  61 /*
  62  * Get contents of register REGNO in task TASK.
  63  */
  64 unsigned long ptrace_get_reg(struct task_struct *task, int regno)
  65 {
  66         unsigned long tmp = 0;
  67
  68         if (task->thread.regs == NULL)
  69                 return -EIO;
  70
  71         if (regno == PT_MSR) {
  72                 tmp = ((unsigned long *)task->thread.regs)[PT_MSR];
  73                 return tmp | task->thread.fpexc_mode;
  74         }
  75
  76         if (regno < (sizeof(struct pt_regs) / sizeof(unsigned long)))
  77                 return ((unsigned long *)task->thread.regs)[regno];
  78
  79         return -EIO;
  80 }
  81
  82 /*
  83  * Write contents of register REGNO in task TASK.
  84  */
  85 int ptrace_put_reg(struct task_struct *task, int regno, unsigned long data)
  86 {
  87         if (task->thread.regs == NULL)
  88                 return -EIO;
  89
  90         if (regno <= PT_MAX_PUT_REG || regno == PT_TRAP) {
  91                 if (regno == PT_MSR)
  92                         data = (data & MSR_DEBUGCHANGE)
  93                                 | (task->thread.regs->msr & ~MSR_DEBUGCHANGE);
  94                 /* We prevent mucking around with the reserved area of trap
  95                  * which are used internally by the kernel
  96                  */
  97                 if (regno == PT_TRAP)
  98                         data &= 0xfff0;
  99                 ((unsigned long *)task->thread.regs)[regno] = data;
 100                 return 0;
 101         }
 102         return -EIO;
 103 }
 104
 105
 106 static int get_fpregs(void __user *data, struct task_struct *task,
 107                       int has_fpscr)
 108 {
 109         unsigned int count = has_fpscr ? 33 : 32;
 110
 111         if (copy_to_user(data, task->thread.fpr, count * sizeof(double)))
 112                 return -EFAULT;
 113         return 0;
 114 }
 115
 116 static int set_fpregs(void __user *data, struct task_struct *task,
 117                       int has_fpscr)
 118 {
 119         unsigned int count = has_fpscr ? 33 : 32;
 120
 121         if (copy_from_user(task->thread.fpr, data, count * sizeof(double)))
 122                 return -EFAULT;
 123         return 0;
 124 }
 125
 126
 127 #ifdef CONFIG_ALTIVEC
 128 /*
 129  * Get/set all the altivec registers vr0..vr31, vscr, vrsave, in one go.
 130  * The transfer totals 34 quadword.  Quadwords 0-31 contain the
 131  * corresponding vector registers.  Quadword 32 contains the vscr as the
 132  * last word (offset 12) within that quadword.  Quadword 33 contains the
 133  * vrsave as the first word (offset 0) within the quadword.
 134  *
 135  * This definition of the VMX state is compatible with the current PPC32
 136  * ptrace interface.  This allows signal handling and ptrace to use the
 137  * same structures.  This also simplifies the implementation of a bi-arch
 138  * (combined (32- and 64-bit) gdb.
 139  */
 140
 141 /*
 142  * Get contents of AltiVec register state in task TASK
 143  */
 144 static int get_vrregs(unsigned long __user *data, struct task_struct *task)
 145 {
 146         unsigned long regsize;
 147
 148         /* copy AltiVec registers VR[0] .. VR[31] */
 149         regsize = 32 * sizeof(vector128);
 150         if (copy_to_user(data, task->thread.vr, regsize))
 151                 return -EFAULT;
 152         data += (regsize / sizeof(unsigned long));
 153
 154         /* copy VSCR */
 155         regsize = 1 * sizeof(vector128);
 156         if (copy_to_user(data, &task->thread.vscr, regsize))
 157                 return -EFAULT;
 158         data += (regsize / sizeof(unsigned long));
 159
 160         /* copy VRSAVE */
 161         if (put_user(task->thread.vrsave, (u32 __user *)data))
 162                 return -EFAULT;
 163
 164         return 0;
 165 }
 166
 167 /*
 168  * Write contents of AltiVec register state into task TASK.
 169  */
 170 static int set_vrregs(struct task_struct *task, unsigned long __user *data)
 171 {
 172         unsigned long regsize;
 173
 174         /* copy AltiVec registers VR[0] .. VR[31] */
 175         regsize = 32 * sizeof(vector128);
 176         if (copy_from_user(task->thread.vr, data, regsize))
 177                 return -EFAULT;
 178         data += (regsize / sizeof(unsigned long));
 179
 180         /* copy VSCR */
 181         regsize = 1 * sizeof(vector128);
 182         if (copy_from_user(&task->thread.vscr, data, regsize))
 183                 return -EFAULT;
 184         data += (regsize / sizeof(unsigned long));
 185
 186         /* copy VRSAVE */
 187         if (get_user(task->thread.vrsave, (u32 __user *)data))
 188                 return -EFAULT;
 189
 190         return 0;
 191 }
 192 #endif /* CONFIG_ALTIVEC */
 193
 194 #ifdef CONFIG_SPE
 195
 196 /*
 197  * For get_evrregs/set_evrregs functions 'data' has the following layout:
 198  *
 199  * struct {
 200  *   u32 evr[32];
 201  *   u64 acc;
 202  *   u32 spefscr;
 203  * }
 204  */
 205
 206 /*
 207  * Get contents of SPE register state in task TASK.
 208  */
 209 static int get_evrregs(unsigned long *data, struct task_struct *task)
 210 {
 211         int i;
 212
 213         if (!access_ok(VERIFY_WRITE, data, 35 * sizeof(unsigned long)))
 214                 return -EFAULT;
 215
 216         /* copy SPEFSCR */
 217         if (__put_user(task->thread.spefscr, &data[34]))
 218                 return -EFAULT;
 219
 220         /* copy SPE registers EVR[0] .. EVR[31] */
 221         for (i = 0; i < 32; i++, data++)
 222                 if (__put_user(task->thread.evr[i], data))
 223                         return -EFAULT;
 224
 225         /* copy ACC */
 226         if (__put_user64(task->thread.acc, (unsigned long long *)data))
 227                 return -EFAULT;
 228
 229         return 0;
 230 }
 231
 232 /*
 233  * Write contents of SPE register state into task TASK.
 234  */
 235 static int set_evrregs(struct task_struct *task, unsigned long *data)
 236 {
 237         int i;
 238
 239         if (!access_ok(VERIFY_READ, data, 35 * sizeof(unsigned long)))
 240                 return -EFAULT;
 241
 242         /* copy SPEFSCR */
 243         if (__get_user(task->thread.spefscr, &data[34]))
 244                 return -EFAULT;
 245
 246         /* copy SPE registers EVR[0] .. EVR[31] */
 247         for (i = 0; i < 32; i++, data++)
 248                 if (__get_user(task->thread.evr[i], data))
 249                         return -EFAULT;
 250         /* copy ACC */
 251         if (__get_user64(task->thread.acc, (unsigned long long*)data))
 252                 return -EFAULT;
 253
 254         return 0;
 255 }
 256 #endif /* CONFIG_SPE */
 257
 258
 259 static void set_single_step(struct task_struct *task)
 260 {
 261         struct pt_regs *regs = task->thread.regs;
 262
 263         if (regs != NULL) {
 264 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 265                 task->thread.dbcr0 = DBCR0_IDM | DBCR0_IC;
 266                 regs->msr |= MSR_DE;
 267 #else
 268                 regs->msr |= MSR_SE;
 269 #endif
 270         }
 271         set_tsk_thread_flag(task, TIF_SINGLESTEP);
 272 }
 273
 274 static void clear_single_step(struct task_struct *task)
 275 {
 276         struct pt_regs *regs = task->thread.regs;
 277
 278         if (regs != NULL) {
 279 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 280                 task->thread.dbcr0 = 0;
 281                 regs->msr &= ~MSR_DE;
 282 #else
 283                 regs->msr &= ~MSR_SE;
 284 #endif
 285         }
 286         clear_tsk_thread_flag(task, TIF_SINGLESTEP);
 287 }
 288
 289 static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
 290                                unsigned long data)
 291 {
 292         /* We only support one DABR and no IABRS at the moment */
 293         if (addr > 0)
 294                 return -EINVAL;
 295
 296         /* The bottom 3 bits are flags */
 297         if ((data & ~0x7UL) >= TASK_SIZE)
 298                 return -EIO;
 299
 300         /* Ensure translation is on */
 301         if (data && !(data & DABR_TRANSLATION))
 302                 return -EIO;
 303
 304         task->thread.dabr = data;
 305         return 0;
 306 }
 307
 308 /*
 309  * Called by kernel/ptrace.c when detaching..
 310  *
 311  * Make sure single step bits etc are not set.
 312  */
 313 void ptrace_disable(struct task_struct *child)
 314 {
 315         /* make sure the single step bit is not set. */
 316         clear_single_step(child);
 317 }
 318
 319 /*
 320  * Here are the old "legacy" powerpc specific getregs/setregs ptrace calls,
 321  * we mark them as obsolete now, they will be removed in a future version
 322  */
 323 static long arch_ptrace_old(struct task_struct *child, long request, long addr,
 324                             long data)
 325 {
 326         int ret = -EPERM;
 327
 328         switch(request) {
 329         case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
 330                 int i;
 331                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 332                 unsigned long __user *tmp = (unsigned long __user *)addr;
 333
 334                 CHECK_FULL_REGS(child->thread.regs);
 335                 for (i = 0; i < 32; i++) {
 336                         ret = put_user(*reg, tmp);
 337                         if (ret)
 338                                 break;
 339                         reg++;
 340                         tmp++;
 341                 }
 342                 break;
 343         }
 344
 345         case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
 346                 int i;
 347                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 348                 unsigned long __user *tmp = (unsigned long __user *)addr;
 349
 350                 CHECK_FULL_REGS(child->thread.regs);
 351                 for (i = 0; i < 32; i++) {
 352                         ret = get_user(*reg, tmp);
 353                         if (ret)
 354                                 break;
 355                         reg++;
 356                         tmp++;
 357                 }
 358                 break;
 359         }
 360
 361         case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
 362                 flush_fp_to_thread(child);
 363                 ret = get_fpregs((void __user *)addr, child, 0);
 364                 break;
 365         }
 366
 367         case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
 368                 flush_fp_to_thread(child);
 369                 ret = set_fpregs((void __user *)addr, child, 0);
 370                 break;
 371         }
 372
 373         }
 374         return ret;
 375 }
 376
 377 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 378 {
 379         int ret = -EPERM;
 380
 381         switch (request) {
 382         /* when I and D space are separate, these will need to be fixed. */
 383         case PTRACE_PEEKTEXT: /* read word at location addr. */
 384         case PTRACE_PEEKDATA:
 385                 ret = generic_ptrace_peekdata(child, addr, data);
 386                 break;
 387
 388         /* read the word at location addr in the USER area. */
 389         case PTRACE_PEEKUSR: {
 390                 unsigned long index, tmp;
 391
 392                 ret = -EIO;
 393                 /* convert to index and check */
 394 #ifdef CONFIG_PPC32
 395                 index = (unsigned long) addr >> 2;
 396                 if ((addr & 3) || (index > PT_FPSCR)
 397                     || (child->thread.regs == NULL))
 398 #else
 399                 index = (unsigned long) addr >> 3;
 400                 if ((addr & 7) || (index > PT_FPSCR))
 401 #endif
 402                         break;
 403
 404                 CHECK_FULL_REGS(child->thread.regs);
 405                 if (index < PT_FPR0) {
 406                         tmp = ptrace_get_reg(child, (int) index);
 407                 } else {
 408                         flush_fp_to_thread(child);
 409                         tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
 410                 }
 411                 ret = put_user(tmp,(unsigned long __user *) data);
 412                 break;
 413         }
 414
 415         /* If I and D space are separate, this will have to be fixed. */
 416         case PTRACE_POKETEXT: /* write the word at location addr. */
 417         case PTRACE_POKEDATA:
 418                 ret = generic_ptrace_pokedata(child, addr, data);
 419                 break;
 420
 421         /* write the word at location addr in the USER area */
 422         case PTRACE_POKEUSR: {
 423                 unsigned long index;
 424
 425                 ret = -EIO;
 426                 /* convert to index and check */
 427 #ifdef CONFIG_PPC32
 428                 index = (unsigned long) addr >> 2;
 429                 if ((addr & 3) || (index > PT_FPSCR)
 430                     || (child->thread.regs == NULL))
 431 #else
 432                 index = (unsigned long) addr >> 3;
 433                 if ((addr & 7) || (index > PT_FPSCR))
 434 #endif
 435                         break;
 436
 437                 CHECK_FULL_REGS(child->thread.regs);
 438                 if (index < PT_FPR0) {
 439                         ret = ptrace_put_reg(child, index, data);
 440                 } else {
 441                         flush_fp_to_thread(child);
 442                         ((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
 443                         ret = 0;
 444                 }
 445                 break;
 446         }
 447
 448         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 449         case PTRACE_CONT: { /* restart after signal. */
 450                 ret = -EIO;
 451                 if (!valid_signal(data))
 452                         break;
 453                 if (request == PTRACE_SYSCALL)
 454                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 455                 else
 456                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 457                 child->exit_code = data;
 458                 /* make sure the single step bit is not set. */
 459                 clear_single_step(child);
 460                 wake_up_process(child);
 461                 ret = 0;
 462                 break;
 463         }
 464
 465 /*
 466  * make the child exit.  Best I can do is send it a sigkill.
 467  * perhaps it should be put in the status that it wants to
 468  * exit.
 469  */
 470         case PTRACE_KILL: {
 471                 ret = 0;
 472                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 473                         break;
 474                 child->exit_code = SIGKILL;
 475                 /* make sure the single step bit is not set. */
 476                 clear_single_step(child);
 477                 wake_up_process(child);
 478                 break;
 479         }
 480
 481         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 482                 ret = -EIO;
 483                 if (!valid_signal(data))
 484                         break;
 485                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 486                 set_single_step(child);
 487                 child->exit_code = data;
 488                 /* give it a chance to run. */
 489                 wake_up_process(child);
 490                 ret = 0;
 491                 break;
 492         }
 493
 494         case PTRACE_GET_DEBUGREG: {
 495                 ret = -EINVAL;
 496                 /* We only support one DABR and no IABRS at the moment */
 497                 if (addr > 0)
 498                         break;
 499                 ret = put_user(child->thread.dabr,
 500                                (unsigned long __user *)data);
 501                 break;
 502         }
 503
 504         case PTRACE_SET_DEBUGREG:
 505                 ret = ptrace_set_debugreg(child, addr, data);
 506                 break;
 507
 508 #ifdef CONFIG_PPC64
 509         case PTRACE_GETREGS64:
 510 #endif
 511         case PTRACE_GETREGS: { /* Get all pt_regs from the child. */
 512                 int ui;
 513                 if (!access_ok(VERIFY_WRITE, (void __user *)data,
 514                                sizeof(struct pt_regs))) {
 515                         ret = -EIO;
 516                         break;
 517                 }
 518                 CHECK_FULL_REGS(child->thread.regs);
 519                 ret = 0;
 520                 for (ui = 0; ui < PT_REGS_COUNT; ui ++) {
 521                         ret |= __put_user(ptrace_get_reg(child, ui),
 522                                           (unsigned long __user *) data);
 523                         data += sizeof(long);
 524                 }
 525                 break;
 526         }
 527
 528 #ifdef CONFIG_PPC64
 529         case PTRACE_SETREGS64:
 530 #endif
 531         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 532                 unsigned long tmp;
 533                 int ui;
 534                 if (!access_ok(VERIFY_READ, (void __user *)data,
 535                                sizeof(struct pt_regs))) {
 536                         ret = -EIO;
 537                         break;
 538                 }
 539                 CHECK_FULL_REGS(child->thread.regs);
 540                 ret = 0;
 541                 for (ui = 0; ui < PT_REGS_COUNT; ui ++) {
 542                         ret = __get_user(tmp, (unsigned long __user *) data);
 543                         if (ret)
 544                                 break;
 545                         ptrace_put_reg(child, ui, tmp);
 546                         data += sizeof(long);
 547                 }
 548                 break;
 549         }
 550
 551         case PTRACE_GETFPREGS: { /* Get the child FPU state (FPR0...31 + FPSCR) */
 552                 flush_fp_to_thread(child);
 553                 ret = get_fpregs((void __user *)data, child, 1);
 554                 break;
 555         }
 556
 557         case PTRACE_SETFPREGS: { /* Set the child FPU state (FPR0...31 + FPSCR) */
 558                 flush_fp_to_thread(child);
 559                 ret = set_fpregs((void __user *)data, child, 1);
 560                 break;
 561         }
 562
 563 #ifdef CONFIG_ALTIVEC
 564         case PTRACE_GETVRREGS:
 565                 /* Get the child altivec register state. */
 566                 flush_altivec_to_thread(child);
 567                 ret = get_vrregs((unsigned long __user *)data, child);
 568                 break;
 569
 570         case PTRACE_SETVRREGS:
 571                 /* Set the child altivec register state. */
 572                 flush_altivec_to_thread(child);
 573                 ret = set_vrregs(child, (unsigned long __user *)data);
 574                 break;
 575 #endif
 576 #ifdef CONFIG_SPE
 577         case PTRACE_GETEVRREGS:
 578                 /* Get the child spe register state. */
 579                 flush_spe_to_thread(child);
 580                 ret = get_evrregs((unsigned long __user *)data, child);
 581                 break;
 582
 583         case PTRACE_SETEVRREGS:
 584                 /* Set the child spe register state. */
 585                 /* this is to clear the MSR_SPE bit to force a reload
 586                  * of register state from memory */
 587                 flush_spe_to_thread(child);
 588                 ret = set_evrregs(child, (unsigned long __user *)data);
 589                 break;
 590 #endif
 591
 592         /* Old reverse args ptrace callss */
 593         case PPC_PTRACE_GETREGS: /* Get GPRs 0 - 31. */
 594         case PPC_PTRACE_SETREGS: /* Set GPRs 0 - 31. */
 595         case PPC_PTRACE_GETFPREGS: /* Get FPRs 0 - 31. */
 596         case PPC_PTRACE_SETFPREGS: /* Get FPRs 0 - 31. */
 597                 ret = arch_ptrace_old(child, request, addr, data);
 598                 break;
 599
 600         default:
 601                 ret = ptrace_request(child, request, addr, data);
 602                 break;
 603         }
 604         return ret;
 605 }
 606
 607 static void do_syscall_trace(void)
 608 {
 609         /* the 0x80 provides a way for the tracing parent to distinguish
 610            between a syscall stop and SIGTRAP delivery */
 611         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 612                                  ? 0x80 : 0));
 613
 614         /*
 615          * this isn't the same as continuing with a signal, but it will do
 616          * for normal use.  strace only continues with a signal if the
 617          * stopping signal is not SIGTRAP.  -brl
 618          */
 619         if (current->exit_code) {
 620                 send_sig(current->exit_code, current, 1);
 621                 current->exit_code = 0;
 622         }
 623 }
 624
 625 void do_syscall_trace_enter(struct pt_regs *regs)
 626 {
 627         secure_computing(regs->gpr[0]);
 628
 629         if (test_thread_flag(TIF_SYSCALL_TRACE)
 630             && (current->ptrace & PT_PTRACED))
 631                 do_syscall_trace();
 632
 633         if (unlikely(current->audit_context)) {
 634 #ifdef CONFIG_PPC64
 635                 if (!test_thread_flag(TIF_32BIT))
 636                         audit_syscall_entry(AUDIT_ARCH_PPC64,
 637                                             regs->gpr[0],
 638                                             regs->gpr[3], regs->gpr[4],
 639                                             regs->gpr[5], regs->gpr[6]);
 640                 else
 641 #endif
 642                         audit_syscall_entry(AUDIT_ARCH_PPC,
 643                                             regs->gpr[0],
 644                                             regs->gpr[3] & 0xffffffff,
 645                                             regs->gpr[4] & 0xffffffff,
 646                                             regs->gpr[5] & 0xffffffff,
 647                                             regs->gpr[6] & 0xffffffff);
 648         }
 649 }
 650
 651 void do_syscall_trace_leave(struct pt_regs *regs)
 652 {
 653         if (unlikely(current->audit_context))
 654                 audit_syscall_exit((regs->ccr&0x10000000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,
 655                                    regs->result);
 656
 657         if ((test_thread_flag(TIF_SYSCALL_TRACE)
 658              || test_thread_flag(TIF_SINGLESTEP))
 659             && (current->ptrace & PT_PTRACED))
 660                 do_syscall_trace();
 661 }