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 #ifdef CONFIG_PPC64
  39 #include "ptrace-ppc64.h"
  40 #else
  41 #include "ptrace-ppc32.h"
  42 #endif
  43
  44 /*
  45  * does not yet catch signals sent when the child dies.
  46  * in exit.c or in signal.c.
  47  */
  48
  49 /*
  50  * Get contents of register REGNO in task TASK.
  51  */
  52 unsigned long ptrace_get_reg(struct task_struct *task, int regno)
  53 {
  54         unsigned long tmp = 0;
  55
  56         if (task->thread.regs == NULL)
  57                 return -EIO;
  58
  59         if (regno == PT_MSR) {
  60                 tmp = ((unsigned long *)task->thread.regs)[PT_MSR];
  61                 return PT_MUNGE_MSR(tmp, task);
  62         }
  63
  64         if (regno < (sizeof(struct pt_regs) / sizeof(unsigned long)))
  65                 return ((unsigned long *)task->thread.regs)[regno];
  66
  67         return -EIO;
  68 }
  69
  70 /*
  71  * Write contents of register REGNO in task TASK.
  72  */
  73 int ptrace_put_reg(struct task_struct *task, int regno, unsigned long data)
  74 {
  75         if (task->thread.regs == NULL)
  76                 return -EIO;
  77
  78         if (regno <= PT_MAX_PUT_REG || regno == PT_TRAP) {
  79                 if (regno == PT_MSR)
  80                         data = (data & MSR_DEBUGCHANGE)
  81                                 | (task->thread.regs->msr & ~MSR_DEBUGCHANGE);
  82                 /* We prevent mucking around with the reserved area of trap
  83                  * which are used internally by the kernel
  84                  */
  85                 if (regno == PT_TRAP)
  86                         data &= 0xfff0;
  87                 ((unsigned long *)task->thread.regs)[regno] = data;
  88                 return 0;
  89         }
  90         return -EIO;
  91 }
  92
  93
  94 static int get_fpregs(void __user *data, struct task_struct *task,
  95                       int has_fpscr)
  96 {
  97         unsigned int count = has_fpscr ? 33 : 32;
  98
  99         if (copy_to_user(data, task->thread.fpr, count * sizeof(double)))
 100                 return -EFAULT;
 101         return 0;
 102 }
 103
 104 static int set_fpregs(void __user *data, struct task_struct *task,
 105                       int has_fpscr)
 106 {
 107         unsigned int count = has_fpscr ? 33 : 32;
 108
 109         if (copy_from_user(task->thread.fpr, data, count * sizeof(double)))
 110                 return -EFAULT;
 111         return 0;
 112 }
 113
 114
 115 #ifdef CONFIG_ALTIVEC
 116 /*
 117  * Get/set all the altivec registers vr0..vr31, vscr, vrsave, in one go.
 118  * The transfer totals 34 quadword.  Quadwords 0-31 contain the
 119  * corresponding vector registers.  Quadword 32 contains the vscr as the
 120  * last word (offset 12) within that quadword.  Quadword 33 contains the
 121  * vrsave as the first word (offset 0) within the quadword.
 122  *
 123  * This definition of the VMX state is compatible with the current PPC32
 124  * ptrace interface.  This allows signal handling and ptrace to use the
 125  * same structures.  This also simplifies the implementation of a bi-arch
 126  * (combined (32- and 64-bit) gdb.
 127  */
 128
 129 /*
 130  * Get contents of AltiVec register state in task TASK
 131  */
 132 static int get_vrregs(unsigned long __user *data, struct task_struct *task)
 133 {
 134         unsigned long regsize;
 135
 136         /* copy AltiVec registers VR[0] .. VR[31] */
 137         regsize = 32 * sizeof(vector128);
 138         if (copy_to_user(data, task->thread.vr, regsize))
 139                 return -EFAULT;
 140         data += (regsize / sizeof(unsigned long));
 141
 142         /* copy VSCR */
 143         regsize = 1 * sizeof(vector128);
 144         if (copy_to_user(data, &task->thread.vscr, regsize))
 145                 return -EFAULT;
 146         data += (regsize / sizeof(unsigned long));
 147
 148         /* copy VRSAVE */
 149         if (put_user(task->thread.vrsave, (u32 __user *)data))
 150                 return -EFAULT;
 151
 152         return 0;
 153 }
 154
 155 /*
 156  * Write contents of AltiVec register state into task TASK.
 157  */
 158 static int set_vrregs(struct task_struct *task, unsigned long __user *data)
 159 {
 160         unsigned long regsize;
 161
 162         /* copy AltiVec registers VR[0] .. VR[31] */
 163         regsize = 32 * sizeof(vector128);
 164         if (copy_from_user(task->thread.vr, data, regsize))
 165                 return -EFAULT;
 166         data += (regsize / sizeof(unsigned long));
 167
 168         /* copy VSCR */
 169         regsize = 1 * sizeof(vector128);
 170         if (copy_from_user(&task->thread.vscr, data, regsize))
 171                 return -EFAULT;
 172         data += (regsize / sizeof(unsigned long));
 173
 174         /* copy VRSAVE */
 175         if (get_user(task->thread.vrsave, (u32 __user *)data))
 176                 return -EFAULT;
 177
 178         return 0;
 179 }
 180 #endif /* CONFIG_ALTIVEC */
 181
 182 #ifdef CONFIG_SPE
 183
 184 /*
 185  * For get_evrregs/set_evrregs functions 'data' has the following layout:
 186  *
 187  * struct {
 188  *   u32 evr[32];
 189  *   u64 acc;
 190  *   u32 spefscr;
 191  * }
 192  */
 193
 194 /*
 195  * Get contents of SPE register state in task TASK.
 196  */
 197 static int get_evrregs(unsigned long *data, struct task_struct *task)
 198 {
 199         int i;
 200
 201         if (!access_ok(VERIFY_WRITE, data, 35 * sizeof(unsigned long)))
 202                 return -EFAULT;
 203
 204         /* copy SPEFSCR */
 205         if (__put_user(task->thread.spefscr, &data[34]))
 206                 return -EFAULT;
 207
 208         /* copy SPE registers EVR[0] .. EVR[31] */
 209         for (i = 0; i < 32; i++, data++)
 210                 if (__put_user(task->thread.evr[i], data))
 211                         return -EFAULT;
 212
 213         /* copy ACC */
 214         if (__put_user64(task->thread.acc, (unsigned long long *)data))
 215                 return -EFAULT;
 216
 217         return 0;
 218 }
 219
 220 /*
 221  * Write contents of SPE register state into task TASK.
 222  */
 223 static int set_evrregs(struct task_struct *task, unsigned long *data)
 224 {
 225         int i;
 226
 227         if (!access_ok(VERIFY_READ, data, 35 * sizeof(unsigned long)))
 228                 return -EFAULT;
 229
 230         /* copy SPEFSCR */
 231         if (__get_user(task->thread.spefscr, &data[34]))
 232                 return -EFAULT;
 233
 234         /* copy SPE registers EVR[0] .. EVR[31] */
 235         for (i = 0; i < 32; i++, data++)
 236                 if (__get_user(task->thread.evr[i], data))
 237                         return -EFAULT;
 238         /* copy ACC */
 239         if (__get_user64(task->thread.acc, (unsigned long long*)data))
 240                 return -EFAULT;
 241
 242         return 0;
 243 }
 244 #endif /* CONFIG_SPE */
 245
 246
 247 static void set_single_step(struct task_struct *task)
 248 {
 249         struct pt_regs *regs = task->thread.regs;
 250
 251         if (regs != NULL) {
 252 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 253                 task->thread.dbcr0 = DBCR0_IDM | DBCR0_IC;
 254                 regs->msr |= MSR_DE;
 255 #else
 256                 regs->msr |= MSR_SE;
 257 #endif
 258         }
 259         set_tsk_thread_flag(task, TIF_SINGLESTEP);
 260 }
 261
 262 static void clear_single_step(struct task_struct *task)
 263 {
 264         struct pt_regs *regs = task->thread.regs;
 265
 266         if (regs != NULL) {
 267 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 268                 task->thread.dbcr0 = 0;
 269                 regs->msr &= ~MSR_DE;
 270 #else
 271                 regs->msr &= ~MSR_SE;
 272 #endif
 273         }
 274         clear_tsk_thread_flag(task, TIF_SINGLESTEP);
 275 }
 276
 277 /*
 278  * Called by kernel/ptrace.c when detaching..
 279  *
 280  * Make sure single step bits etc are not set.
 281  */
 282 void ptrace_disable(struct task_struct *child)
 283 {
 284         /* make sure the single step bit is not set. */
 285         clear_single_step(child);
 286 }
 287
 288 /*
 289  * Here are the old "legacy" powerpc specific getregs/setregs ptrace calls,
 290  * we mark them as obsolete now, they will be removed in a future version
 291  */
 292 static long arch_ptrace_old(struct task_struct *child, long request, long addr,
 293                             long data)
 294 {
 295         int ret = -EPERM;
 296
 297         switch(request) {
 298         case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
 299                 int i;
 300                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 301                 unsigned long __user *tmp = (unsigned long __user *)addr;
 302
 303                 for (i = 0; i < 32; i++) {
 304                         ret = put_user(*reg, tmp);
 305                         if (ret)
 306                                 break;
 307                         reg++;
 308                         tmp++;
 309                 }
 310                 break;
 311         }
 312
 313         case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
 314                 int i;
 315                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 316                 unsigned long __user *tmp = (unsigned long __user *)addr;
 317
 318                 for (i = 0; i < 32; i++) {
 319                         ret = get_user(*reg, tmp);
 320                         if (ret)
 321                                 break;
 322                         reg++;
 323                         tmp++;
 324                 }
 325                 break;
 326         }
 327
 328         case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
 329                 flush_fp_to_thread(child);
 330                 ret = get_fpregs((void __user *)addr, child, 0);
 331                 break;
 332         }
 333
 334         case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
 335                 flush_fp_to_thread(child);
 336                 ret = set_fpregs((void __user *)addr, child, 0);
 337                 break;
 338         }
 339
 340         }
 341         return ret;
 342 }
 343
 344 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 345 {
 346         int ret = -EPERM;
 347
 348         switch (request) {
 349         /* when I and D space are separate, these will need to be fixed. */
 350         case PTRACE_PEEKTEXT: /* read word at location addr. */
 351         case PTRACE_PEEKDATA: {
 352                 unsigned long tmp;
 353                 int copied;
 354
 355                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 356                 ret = -EIO;
 357                 if (copied != sizeof(tmp))
 358                         break;
 359                 ret = put_user(tmp,(unsigned long __user *) data);
 360                 break;
 361         }
 362
 363         /* read the word at location addr in the USER area. */
 364         case PTRACE_PEEKUSR: {
 365                 unsigned long index, tmp;
 366
 367                 ret = -EIO;
 368                 /* convert to index and check */
 369 #ifdef CONFIG_PPC32
 370                 index = (unsigned long) addr >> 2;
 371                 if ((addr & 3) || (index > PT_FPSCR)
 372                     || (child->thread.regs == NULL))
 373 #else
 374                 index = (unsigned long) addr >> 3;
 375                 if ((addr & 7) || (index > PT_FPSCR))
 376 #endif
 377                         break;
 378
 379                 CHECK_FULL_REGS(child->thread.regs);
 380                 if (index < PT_FPR0) {
 381                         tmp = ptrace_get_reg(child, (int) index);
 382                 } else {
 383                         flush_fp_to_thread(child);
 384                         tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
 385                 }
 386                 ret = put_user(tmp,(unsigned long __user *) data);
 387                 break;
 388         }
 389
 390         /* If I and D space are separate, this will have to be fixed. */
 391         case PTRACE_POKETEXT: /* write the word at location addr. */
 392         case PTRACE_POKEDATA:
 393                 ret = 0;
 394                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 395                                 == sizeof(data))
 396                         break;
 397                 ret = -EIO;
 398                 break;
 399
 400         /* write the word at location addr in the USER area */
 401         case PTRACE_POKEUSR: {
 402                 unsigned long index;
 403
 404                 ret = -EIO;
 405                 /* convert to index and check */
 406 #ifdef CONFIG_PPC32
 407                 index = (unsigned long) addr >> 2;
 408                 if ((addr & 3) || (index > PT_FPSCR)
 409                     || (child->thread.regs == NULL))
 410 #else
 411                 index = (unsigned long) addr >> 3;
 412                 if ((addr & 7) || (index > PT_FPSCR))
 413 #endif
 414                         break;
 415
 416                 CHECK_FULL_REGS(child->thread.regs);
 417                 if (index < PT_FPR0) {
 418                         ret = ptrace_put_reg(child, index, data);
 419                 } else {
 420                         flush_fp_to_thread(child);
 421                         ((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
 422                         ret = 0;
 423                 }
 424                 break;
 425         }
 426
 427         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 428         case PTRACE_CONT: { /* restart after signal. */
 429                 ret = -EIO;
 430                 if (!valid_signal(data))
 431                         break;
 432                 if (request == PTRACE_SYSCALL)
 433                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 434                 else
 435                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 436                 child->exit_code = data;
 437                 /* make sure the single step bit is not set. */
 438                 clear_single_step(child);
 439                 wake_up_process(child);
 440                 ret = 0;
 441                 break;
 442         }
 443
 444 /*
 445  * make the child exit.  Best I can do is send it a sigkill.
 446  * perhaps it should be put in the status that it wants to
 447  * exit.
 448  */
 449         case PTRACE_KILL: {
 450                 ret = 0;
 451                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 452                         break;
 453                 child->exit_code = SIGKILL;
 454                 /* make sure the single step bit is not set. */
 455                 clear_single_step(child);
 456                 wake_up_process(child);
 457                 break;
 458         }
 459
 460         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 461                 ret = -EIO;
 462                 if (!valid_signal(data))
 463                         break;
 464                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 465                 set_single_step(child);
 466                 child->exit_code = data;
 467                 /* give it a chance to run. */
 468                 wake_up_process(child);
 469                 ret = 0;
 470                 break;
 471         }
 472
 473 #ifdef CONFIG_PPC64
 474         case PTRACE_GET_DEBUGREG: {
 475                 ret = -EINVAL;
 476                 /* We only support one DABR and no IABRS at the moment */
 477                 if (addr > 0)
 478                         break;
 479                 ret = put_user(child->thread.dabr,
 480                                (unsigned long __user *)data);
 481                 break;
 482         }
 483
 484         case PTRACE_SET_DEBUGREG:
 485                 ret = ptrace_set_debugreg(child, addr, data);
 486                 break;
 487 #endif
 488
 489         case PTRACE_DETACH:
 490                 ret = ptrace_detach(child, data);
 491                 break;
 492
 493 #ifdef CONFIG_PPC64
 494         case PTRACE_GETREGS64:
 495 #endif
 496         case PTRACE_GETREGS: { /* Get all pt_regs from the child. */
 497                 int ui;
 498                 if (!access_ok(VERIFY_WRITE, (void __user *)data,
 499                                sizeof(struct pt_regs))) {
 500                         ret = -EIO;
 501                         break;
 502                 }
 503                 ret = 0;
 504                 for (ui = 0; ui < PT_REGS_COUNT; ui ++) {
 505                         ret |= __put_user(ptrace_get_reg(child, ui),
 506                                           (unsigned long __user *) data);
 507                         data += sizeof(long);
 508                 }
 509                 break;
 510         }
 511
 512 #ifdef CONFIG_PPC64
 513         case PTRACE_SETREGS64:
 514 #endif
 515         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 516                 unsigned long tmp;
 517                 int ui;
 518                 if (!access_ok(VERIFY_READ, (void __user *)data,
 519                                sizeof(struct pt_regs))) {
 520                         ret = -EIO;
 521                         break;
 522                 }
 523                 ret = 0;
 524                 for (ui = 0; ui < PT_REGS_COUNT; ui ++) {
 525                         ret = __get_user(tmp, (unsigned long __user *) data);
 526                         if (ret)
 527                                 break;
 528                         ptrace_put_reg(child, ui, tmp);
 529                         data += sizeof(long);
 530                 }
 531                 break;
 532         }
 533
 534         case PTRACE_GETFPREGS: { /* Get the child FPU state (FPR0...31 + FPSCR) */
 535                 flush_fp_to_thread(child);
 536                 ret = get_fpregs((void __user *)data, child, 1);
 537                 break;
 538         }
 539
 540         case PTRACE_SETFPREGS: { /* Set the child FPU state (FPR0...31 + FPSCR) */
 541                 flush_fp_to_thread(child);
 542                 ret = set_fpregs((void __user *)data, child, 1);
 543                 break;
 544         }
 545
 546 #ifdef CONFIG_ALTIVEC
 547         case PTRACE_GETVRREGS:
 548                 /* Get the child altivec register state. */
 549                 flush_altivec_to_thread(child);
 550                 ret = get_vrregs((unsigned long __user *)data, child);
 551                 break;
 552
 553         case PTRACE_SETVRREGS:
 554                 /* Set the child altivec register state. */
 555                 flush_altivec_to_thread(child);
 556                 ret = set_vrregs(child, (unsigned long __user *)data);
 557                 break;
 558 #endif
 559 #ifdef CONFIG_SPE
 560         case PTRACE_GETEVRREGS:
 561                 /* Get the child spe register state. */
 562                 if (child->thread.regs->msr & MSR_SPE)
 563                         giveup_spe(child);
 564                 ret = get_evrregs((unsigned long __user *)data, child);
 565                 break;
 566
 567         case PTRACE_SETEVRREGS:
 568                 /* Set the child spe register state. */
 569                 /* this is to clear the MSR_SPE bit to force a reload
 570                  * of register state from memory */
 571                 if (child->thread.regs->msr & MSR_SPE)
 572                         giveup_spe(child);
 573                 ret = set_evrregs(child, (unsigned long __user *)data);
 574                 break;
 575 #endif
 576
 577         /* Old reverse args ptrace callss */
 578         case PPC_PTRACE_GETREGS: /* Get GPRs 0 - 31. */
 579         case PPC_PTRACE_SETREGS: /* Set GPRs 0 - 31. */
 580         case PPC_PTRACE_GETFPREGS: /* Get FPRs 0 - 31. */
 581         case PPC_PTRACE_SETFPREGS: /* Get FPRs 0 - 31. */
 582                 ret = arch_ptrace_old(child, request, addr, data);
 583                 break;
 584
 585         default:
 586                 ret = ptrace_request(child, request, addr, data);
 587                 break;
 588         }
 589         return ret;
 590 }
 591
 592 static void do_syscall_trace(void)
 593 {
 594         /* the 0x80 provides a way for the tracing parent to distinguish
 595            between a syscall stop and SIGTRAP delivery */
 596         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 597                                  ? 0x80 : 0));
 598
 599         /*
 600          * this isn't the same as continuing with a signal, but it will do
 601          * for normal use.  strace only continues with a signal if the
 602          * stopping signal is not SIGTRAP.  -brl
 603          */
 604         if (current->exit_code) {
 605                 send_sig(current->exit_code, current, 1);
 606                 current->exit_code = 0;
 607         }
 608 }
 609
 610 void do_syscall_trace_enter(struct pt_regs *regs)
 611 {
 612         secure_computing(regs->gpr[0]);
 613
 614         if (test_thread_flag(TIF_SYSCALL_TRACE)
 615             && (current->ptrace & PT_PTRACED))
 616                 do_syscall_trace();
 617
 618         if (unlikely(current->audit_context)) {
 619 #ifdef CONFIG_PPC64
 620                 if (!test_thread_flag(TIF_32BIT))
 621                         audit_syscall_entry(AUDIT_ARCH_PPC64,
 622                                             regs->gpr[0],
 623                                             regs->gpr[3], regs->gpr[4],
 624                                             regs->gpr[5], regs->gpr[6]);
 625                 else
 626 #endif
 627                         audit_syscall_entry(AUDIT_ARCH_PPC,
 628                                             regs->gpr[0],
 629                                             regs->gpr[3] & 0xffffffff,
 630                                             regs->gpr[4] & 0xffffffff,
 631                                             regs->gpr[5] & 0xffffffff,
 632                                             regs->gpr[6] & 0xffffffff);
 633         }
 634 }
 635
 636 void do_syscall_trace_leave(struct pt_regs *regs)
 637 {
 638         if (unlikely(current->audit_context))
 639                 audit_syscall_exit((regs->ccr&0x10000000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,
 640                                    regs->result);
 641
 642         if ((test_thread_flag(TIF_SYSCALL_TRACE)
 643              || test_thread_flag(TIF_SINGLESTEP))
 644             && (current->ptrace & PT_PTRACED))
 645                 do_syscall_trace();
 646 }