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/config.h>
  19 #include <linux/kernel.h>
  20 #include <linux/sched.h>
  21 #include <linux/mm.h>
  22 #include <linux/smp.h>
  23 #include <linux/smp_lock.h>
  24 #include <linux/errno.h>
  25 #include <linux/ptrace.h>
  26 #include <linux/user.h>
  27 #include <linux/security.h>
  28 #include <linux/signal.h>
  29 #include <linux/seccomp.h>
  30 #include <linux/audit.h>
  31 #ifdef CONFIG_PPC32
  32 #include <linux/module.h>
  33 #endif
  34
  35 #include <asm/uaccess.h>
  36 #include <asm/page.h>
  37 #include <asm/pgtable.h>
  38 #include <asm/system.h>
  39 #ifdef CONFIG_PPC64
  40 #include <asm/ptrace-common.h>
  41 #endif
  42
  43 #ifdef CONFIG_PPC32
  44 /*
  45  * Set of msr bits that gdb can change on behalf of a process.
  46  */
  47 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
  48 #define MSR_DEBUGCHANGE 0
  49 #else
  50 #define MSR_DEBUGCHANGE (MSR_SE | MSR_BE)
  51 #endif
  52 #endif /* CONFIG_PPC32 */
  53
  54 /*
  55  * does not yet catch signals sent when the child dies.
  56  * in exit.c or in signal.c.
  57  */
  58
  59 #ifdef CONFIG_PPC32
  60 /*
  61  * Get contents of register REGNO in task TASK.
  62  */
  63 static inline unsigned long get_reg(struct task_struct *task, int regno)
  64 {
  65         if (regno < sizeof(struct pt_regs) / sizeof(unsigned long)
  66             && task->thread.regs != NULL)
  67                 return ((unsigned long *)task->thread.regs)[regno];
  68         return (0);
  69 }
  70
  71 /*
  72  * Write contents of register REGNO in task TASK.
  73  */
  74 static inline int put_reg(struct task_struct *task, int regno,
  75                           unsigned long data)
  76 {
  77         if (regno <= PT_MQ && task->thread.regs != NULL) {
  78                 if (regno == PT_MSR)
  79                         data = (data & MSR_DEBUGCHANGE)
  80                                 | (task->thread.regs->msr & ~MSR_DEBUGCHANGE);
  81                 ((unsigned long *)task->thread.regs)[regno] = data;
  82                 return 0;
  83         }
  84         return -EIO;
  85 }
  86
  87 #ifdef CONFIG_ALTIVEC
  88 /*
  89  * Get contents of AltiVec register state in task TASK
  90  */
  91 static inline int get_vrregs(unsigned long __user *data, struct task_struct *task)
  92 {
  93         int i, j;
  94
  95         if (!access_ok(VERIFY_WRITE, data, 133 * sizeof(unsigned long)))
  96                 return -EFAULT;
  97
  98         /* copy AltiVec registers VR[0] .. VR[31] */
  99         for (i = 0; i < 32; i++)
 100                 for (j = 0; j < 4; j++, data++)
 101                         if (__put_user(task->thread.vr[i].u[j], data))
 102                                 return -EFAULT;
 103
 104         /* copy VSCR */
 105         for (i = 0; i < 4; i++, data++)
 106                 if (__put_user(task->thread.vscr.u[i], data))
 107                         return -EFAULT;
 108
 109         /* copy VRSAVE */
 110         if (__put_user(task->thread.vrsave, data))
 111                 return -EFAULT;
 112
 113         return 0;
 114 }
 115
 116 /*
 117  * Write contents of AltiVec register state into task TASK.
 118  */
 119 static inline int set_vrregs(struct task_struct *task, unsigned long __user *data)
 120 {
 121         int i, j;
 122
 123         if (!access_ok(VERIFY_READ, data, 133 * sizeof(unsigned long)))
 124                 return -EFAULT;
 125
 126         /* copy AltiVec registers VR[0] .. VR[31] */
 127         for (i = 0; i < 32; i++)
 128                 for (j = 0; j < 4; j++, data++)
 129                         if (__get_user(task->thread.vr[i].u[j], data))
 130                                 return -EFAULT;
 131
 132         /* copy VSCR */
 133         for (i = 0; i < 4; i++, data++)
 134                 if (__get_user(task->thread.vscr.u[i], data))
 135                         return -EFAULT;
 136
 137         /* copy VRSAVE */
 138         if (__get_user(task->thread.vrsave, data))
 139                 return -EFAULT;
 140
 141         return 0;
 142 }
 143 #endif
 144
 145 #ifdef CONFIG_SPE
 146
 147 /*
 148  * For get_evrregs/set_evrregs functions 'data' has the following layout:
 149  *
 150  * struct {
 151  *   u32 evr[32];
 152  *   u64 acc;
 153  *   u32 spefscr;
 154  * }
 155  */
 156
 157 /*
 158  * Get contents of SPE register state in task TASK.
 159  */
 160 static inline int get_evrregs(unsigned long *data, struct task_struct *task)
 161 {
 162         int i;
 163
 164         if (!access_ok(VERIFY_WRITE, data, 35 * sizeof(unsigned long)))
 165                 return -EFAULT;
 166
 167         /* copy SPEFSCR */
 168         if (__put_user(task->thread.spefscr, &data[34]))
 169                 return -EFAULT;
 170
 171         /* copy SPE registers EVR[0] .. EVR[31] */
 172         for (i = 0; i < 32; i++, data++)
 173                 if (__put_user(task->thread.evr[i], data))
 174                         return -EFAULT;
 175
 176         /* copy ACC */
 177         if (__put_user64(task->thread.acc, (unsigned long long *)data))
 178                 return -EFAULT;
 179
 180         return 0;
 181 }
 182
 183 /*
 184  * Write contents of SPE register state into task TASK.
 185  */
 186 static inline int set_evrregs(struct task_struct *task, unsigned long *data)
 187 {
 188         int i;
 189
 190         if (!access_ok(VERIFY_READ, data, 35 * sizeof(unsigned long)))
 191                 return -EFAULT;
 192
 193         /* copy SPEFSCR */
 194         if (__get_user(task->thread.spefscr, &data[34]))
 195                 return -EFAULT;
 196
 197         /* copy SPE registers EVR[0] .. EVR[31] */
 198         for (i = 0; i < 32; i++, data++)
 199                 if (__get_user(task->thread.evr[i], data))
 200                         return -EFAULT;
 201         /* copy ACC */
 202         if (__get_user64(task->thread.acc, (unsigned long long*)data))
 203                 return -EFAULT;
 204
 205         return 0;
 206 }
 207 #endif /* CONFIG_SPE */
 208
 209 static inline void
 210 set_single_step(struct task_struct *task)
 211 {
 212         struct pt_regs *regs = task->thread.regs;
 213
 214         if (regs != NULL) {
 215 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 216                 task->thread.dbcr0 = DBCR0_IDM | DBCR0_IC;
 217                 regs->msr |= MSR_DE;
 218 #else
 219                 regs->msr |= MSR_SE;
 220 #endif
 221         }
 222 }
 223
 224 static inline void
 225 clear_single_step(struct task_struct *task)
 226 {
 227         struct pt_regs *regs = task->thread.regs;
 228
 229         if (regs != NULL) {
 230 #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
 231                 task->thread.dbcr0 = 0;
 232                 regs->msr &= ~MSR_DE;
 233 #else
 234                 regs->msr &= ~MSR_SE;
 235 #endif
 236         }
 237 }
 238 #endif /* CONFIG_PPC32 */
 239
 240 /*
 241  * Called by kernel/ptrace.c when detaching..
 242  *
 243  * Make sure single step bits etc are not set.
 244  */
 245 void ptrace_disable(struct task_struct *child)
 246 {
 247         /* make sure the single step bit is not set. */
 248         clear_single_step(child);
 249 }
 250
 251 int sys_ptrace(long request, long pid, long addr, long data)
 252 {
 253         struct task_struct *child;
 254         int ret = -EPERM;
 255
 256         lock_kernel();
 257         if (request == PTRACE_TRACEME) {
 258                 /* are we already being traced? */
 259                 if (current->ptrace & PT_PTRACED)
 260                         goto out;
 261                 ret = security_ptrace(current->parent, current);
 262                 if (ret)
 263                         goto out;
 264                 /* set the ptrace bit in the process flags. */
 265                 current->ptrace |= PT_PTRACED;
 266                 ret = 0;
 267                 goto out;
 268         }
 269         ret = -ESRCH;
 270         read_lock(&tasklist_lock);
 271         child = find_task_by_pid(pid);
 272         if (child)
 273                 get_task_struct(child);
 274         read_unlock(&tasklist_lock);
 275         if (!child)
 276                 goto out;
 277
 278         ret = -EPERM;
 279         if (pid == 1)           /* you may not mess with init */
 280                 goto out_tsk;
 281
 282         if (request == PTRACE_ATTACH) {
 283                 ret = ptrace_attach(child);
 284                 goto out_tsk;
 285         }
 286
 287         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 288         if (ret < 0)
 289                 goto out_tsk;
 290
 291         switch (request) {
 292         /* when I and D space are separate, these will need to be fixed. */
 293         case PTRACE_PEEKTEXT: /* read word at location addr. */
 294         case PTRACE_PEEKDATA: {
 295                 unsigned long tmp;
 296                 int copied;
 297
 298                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 299                 ret = -EIO;
 300                 if (copied != sizeof(tmp))
 301                         break;
 302                 ret = put_user(tmp,(unsigned long __user *) data);
 303                 break;
 304         }
 305
 306         /* read the word at location addr in the USER area. */
 307         case PTRACE_PEEKUSR: {
 308                 unsigned long index, tmp;
 309
 310                 ret = -EIO;
 311                 /* convert to index and check */
 312 #ifdef CONFIG_PPC32
 313                 index = (unsigned long) addr >> 2;
 314                 if ((addr & 3) || (index > PT_FPSCR)
 315                     || (child->thread.regs == NULL))
 316 #else
 317                 index = (unsigned long) addr >> 3;
 318                 if ((addr & 7) || (index > PT_FPSCR))
 319 #endif
 320                         break;
 321
 322 #ifdef CONFIG_PPC32
 323                 CHECK_FULL_REGS(child->thread.regs);
 324 #endif
 325                 if (index < PT_FPR0) {
 326                         tmp = get_reg(child, (int) index);
 327                 } else {
 328                         flush_fp_to_thread(child);
 329                         tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
 330                 }
 331                 ret = put_user(tmp,(unsigned long __user *) data);
 332                 break;
 333         }
 334
 335         /* If I and D space are separate, this will have to be fixed. */
 336         case PTRACE_POKETEXT: /* write the word at location addr. */
 337         case PTRACE_POKEDATA:
 338                 ret = 0;
 339                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 340                                 == sizeof(data))
 341                         break;
 342                 ret = -EIO;
 343                 break;
 344
 345         /* write the word at location addr in the USER area */
 346         case PTRACE_POKEUSR: {
 347                 unsigned long index;
 348
 349                 ret = -EIO;
 350                 /* convert to index and check */
 351 #ifdef CONFIG_PPC32
 352                 index = (unsigned long) addr >> 2;
 353                 if ((addr & 3) || (index > PT_FPSCR)
 354                     || (child->thread.regs == NULL))
 355 #else
 356                 index = (unsigned long) addr >> 3;
 357                 if ((addr & 7) || (index > PT_FPSCR))
 358 #endif
 359                         break;
 360
 361 #ifdef CONFIG_PPC32
 362                 CHECK_FULL_REGS(child->thread.regs);
 363 #endif
 364                 if (index == PT_ORIG_R3)
 365                         break;
 366                 if (index < PT_FPR0) {
 367                         ret = put_reg(child, index, data);
 368                 } else {
 369                         flush_fp_to_thread(child);
 370                         ((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
 371                         ret = 0;
 372                 }
 373                 break;
 374         }
 375
 376         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 377         case PTRACE_CONT: { /* restart after signal. */
 378                 ret = -EIO;
 379                 if (!valid_signal(data))
 380                         break;
 381                 if (request == PTRACE_SYSCALL)
 382                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 383                 else
 384                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 385                 child->exit_code = data;
 386                 /* make sure the single step bit is not set. */
 387                 clear_single_step(child);
 388                 wake_up_process(child);
 389                 ret = 0;
 390                 break;
 391         }
 392
 393 /*
 394  * make the child exit.  Best I can do is send it a sigkill.
 395  * perhaps it should be put in the status that it wants to
 396  * exit.
 397  */
 398         case PTRACE_KILL: {
 399                 ret = 0;
 400                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 401                         break;
 402                 child->exit_code = SIGKILL;
 403                 /* make sure the single step bit is not set. */
 404                 clear_single_step(child);
 405                 wake_up_process(child);
 406                 break;
 407         }
 408
 409         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 410                 ret = -EIO;
 411                 if (!valid_signal(data))
 412                         break;
 413                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 414                 set_single_step(child);
 415                 child->exit_code = data;
 416                 /* give it a chance to run. */
 417                 wake_up_process(child);
 418                 ret = 0;
 419                 break;
 420         }
 421
 422 #ifdef CONFIG_PPC64
 423         case PTRACE_GET_DEBUGREG: {
 424                 ret = -EINVAL;
 425                 /* We only support one DABR and no IABRS at the moment */
 426                 if (addr > 0)
 427                         break;
 428                 ret = put_user(child->thread.dabr,
 429                                (unsigned long __user *)data);
 430                 break;
 431         }
 432
 433         case PTRACE_SET_DEBUGREG:
 434                 ret = ptrace_set_debugreg(child, addr, data);
 435                 break;
 436 #endif
 437
 438         case PTRACE_DETACH:
 439                 ret = ptrace_detach(child, data);
 440                 break;
 441
 442 #ifdef CONFIG_PPC64
 443         case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
 444                 int i;
 445                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 446                 unsigned long __user *tmp = (unsigned long __user *)addr;
 447
 448                 for (i = 0; i < 32; i++) {
 449                         ret = put_user(*reg, tmp);
 450                         if (ret)
 451                                 break;
 452                         reg++;
 453                         tmp++;
 454                 }
 455                 break;
 456         }
 457
 458         case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
 459                 int i;
 460                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 461                 unsigned long __user *tmp = (unsigned long __user *)addr;
 462
 463                 for (i = 0; i < 32; i++) {
 464                         ret = get_user(*reg, tmp);
 465                         if (ret)
 466                                 break;
 467                         reg++;
 468                         tmp++;
 469                 }
 470                 break;
 471         }
 472
 473         case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
 474                 int i;
 475                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 476                 unsigned long __user *tmp = (unsigned long __user *)addr;
 477
 478                 flush_fp_to_thread(child);
 479
 480                 for (i = 0; i < 32; i++) {
 481                         ret = put_user(*reg, tmp);
 482                         if (ret)
 483                                 break;
 484                         reg++;
 485                         tmp++;
 486                 }
 487                 break;
 488         }
 489
 490         case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
 491                 int i;
 492                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 493                 unsigned long __user *tmp = (unsigned long __user *)addr;
 494
 495                 flush_fp_to_thread(child);
 496
 497                 for (i = 0; i < 32; i++) {
 498                         ret = get_user(*reg, tmp);
 499                         if (ret)
 500                                 break;
 501                         reg++;
 502                         tmp++;
 503                 }
 504                 break;
 505         }
 506 #endif /* CONFIG_PPC64 */
 507
 508 #ifdef CONFIG_ALTIVEC
 509         case PTRACE_GETVRREGS:
 510                 /* Get the child altivec register state. */
 511                 flush_altivec_to_thread(child);
 512                 ret = get_vrregs((unsigned long __user *)data, child);
 513                 break;
 514
 515         case PTRACE_SETVRREGS:
 516                 /* Set the child altivec register state. */
 517                 flush_altivec_to_thread(child);
 518                 ret = set_vrregs(child, (unsigned long __user *)data);
 519                 break;
 520 #endif
 521 #ifdef CONFIG_SPE
 522         case PTRACE_GETEVRREGS:
 523                 /* Get the child spe register state. */
 524                 if (child->thread.regs->msr & MSR_SPE)
 525                         giveup_spe(child);
 526                 ret = get_evrregs((unsigned long __user *)data, child);
 527                 break;
 528
 529         case PTRACE_SETEVRREGS:
 530                 /* Set the child spe register state. */
 531                 /* this is to clear the MSR_SPE bit to force a reload
 532                  * of register state from memory */
 533                 if (child->thread.regs->msr & MSR_SPE)
 534                         giveup_spe(child);
 535                 ret = set_evrregs(child, (unsigned long __user *)data);
 536                 break;
 537 #endif
 538
 539         default:
 540                 ret = ptrace_request(child, request, addr, data);
 541                 break;
 542         }
 543 out_tsk:
 544         put_task_struct(child);
 545 out:
 546         unlock_kernel();
 547         return ret;
 548 }
 549
 550 static void do_syscall_trace(void)
 551 {
 552         /* the 0x80 provides a way for the tracing parent to distinguish
 553            between a syscall stop and SIGTRAP delivery */
 554         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 555                                  ? 0x80 : 0));
 556
 557         /*
 558          * this isn't the same as continuing with a signal, but it will do
 559          * for normal use.  strace only continues with a signal if the
 560          * stopping signal is not SIGTRAP.  -brl
 561          */
 562         if (current->exit_code) {
 563                 send_sig(current->exit_code, current, 1);
 564                 current->exit_code = 0;
 565         }
 566 }
 567
 568 void do_syscall_trace_enter(struct pt_regs *regs)
 569 {
 570 #ifdef CONFIG_PPC64
 571         secure_computing(regs->gpr[0]);
 572 #endif
 573
 574         if (test_thread_flag(TIF_SYSCALL_TRACE)
 575             && (current->ptrace & PT_PTRACED))
 576                 do_syscall_trace();
 577
 578         if (unlikely(current->audit_context))
 579                 audit_syscall_entry(current,
 580 #ifdef CONFIG_PPC32
 581                                     AUDIT_ARCH_PPC,
 582 #else
 583                                     test_thread_flag(TIF_32BIT)?AUDIT_ARCH_PPC:AUDIT_ARCH_PPC64,
 584 #endif
 585                                     regs->gpr[0],
 586                                     regs->gpr[3], regs->gpr[4],
 587                                     regs->gpr[5], regs->gpr[6]);
 588 }
 589
 590 void do_syscall_trace_leave(struct pt_regs *regs)
 591 {
 592 #ifdef CONFIG_PPC32
 593         secure_computing(regs->gpr[0]);
 594 #endif
 595
 596         if (unlikely(current->audit_context))
 597                 audit_syscall_exit(current,
 598                                    (regs->ccr&0x1000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,
 599                                    regs->result);
 600
 601         if ((test_thread_flag(TIF_SYSCALL_TRACE)
 602 #ifdef CONFIG_PPC64
 603              || test_thread_flag(TIF_SINGLESTEP)
 604 #endif
 605              )
 606             && (current->ptrace & PT_PTRACED))
 607                 do_syscall_trace();
 608 }
 609
 610 #ifdef CONFIG_PPC32
 611 EXPORT_SYMBOL(do_syscall_trace_enter);
 612 EXPORT_SYMBOL(do_syscall_trace_leave);
 613 #endif