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/smp_lock.h>
  23 #include <linux/errno.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/user.h>
  26 #include <linux/security.h>
  27 #include <linux/signal.h>
  28 #include <linux/seccomp.h>
  29 #include <linux/audit.h>
  30 #ifdef CONFIG_PPC32
  31 #include <linux/module.h>
  32 #endif
  33
  34 #include <asm/uaccess.h>
  35 #include <asm/page.h>
  36 #include <asm/pgtable.h>
  37 #include <asm/system.h>
  38
  39 #ifdef CONFIG_PPC64
  40 #include "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 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 252 {
 253         int ret = -EPERM;
 254
 255         switch (request) {
 256         /* when I and D space are separate, these will need to be fixed. */
 257         case PTRACE_PEEKTEXT: /* read word at location addr. */
 258         case PTRACE_PEEKDATA: {
 259                 unsigned long tmp;
 260                 int copied;
 261
 262                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 263                 ret = -EIO;
 264                 if (copied != sizeof(tmp))
 265                         break;
 266                 ret = put_user(tmp,(unsigned long __user *) data);
 267                 break;
 268         }
 269
 270         /* read the word at location addr in the USER area. */
 271         case PTRACE_PEEKUSR: {
 272                 unsigned long index, tmp;
 273
 274                 ret = -EIO;
 275                 /* convert to index and check */
 276 #ifdef CONFIG_PPC32
 277                 index = (unsigned long) addr >> 2;
 278                 if ((addr & 3) || (index > PT_FPSCR)
 279                     || (child->thread.regs == NULL))
 280 #else
 281                 index = (unsigned long) addr >> 3;
 282                 if ((addr & 7) || (index > PT_FPSCR))
 283 #endif
 284                         break;
 285
 286 #ifdef CONFIG_PPC32
 287                 CHECK_FULL_REGS(child->thread.regs);
 288 #endif
 289                 if (index < PT_FPR0) {
 290                         tmp = get_reg(child, (int) index);
 291                 } else {
 292                         flush_fp_to_thread(child);
 293                         tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
 294                 }
 295                 ret = put_user(tmp,(unsigned long __user *) data);
 296                 break;
 297         }
 298
 299         /* If I and D space are separate, this will have to be fixed. */
 300         case PTRACE_POKETEXT: /* write the word at location addr. */
 301         case PTRACE_POKEDATA:
 302                 ret = 0;
 303                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 304                                 == sizeof(data))
 305                         break;
 306                 ret = -EIO;
 307                 break;
 308
 309         /* write the word at location addr in the USER area */
 310         case PTRACE_POKEUSR: {
 311                 unsigned long index;
 312
 313                 ret = -EIO;
 314                 /* convert to index and check */
 315 #ifdef CONFIG_PPC32
 316                 index = (unsigned long) addr >> 2;
 317                 if ((addr & 3) || (index > PT_FPSCR)
 318                     || (child->thread.regs == NULL))
 319 #else
 320                 index = (unsigned long) addr >> 3;
 321                 if ((addr & 7) || (index > PT_FPSCR))
 322 #endif
 323                         break;
 324
 325 #ifdef CONFIG_PPC32
 326                 CHECK_FULL_REGS(child->thread.regs);
 327 #endif
 328                 if (index == PT_ORIG_R3)
 329                         break;
 330                 if (index < PT_FPR0) {
 331                         ret = put_reg(child, index, data);
 332                 } else {
 333                         flush_fp_to_thread(child);
 334                         ((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
 335                         ret = 0;
 336                 }
 337                 break;
 338         }
 339
 340         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 341         case PTRACE_CONT: { /* restart after signal. */
 342                 ret = -EIO;
 343                 if (!valid_signal(data))
 344                         break;
 345                 if (request == PTRACE_SYSCALL)
 346                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 347                 else
 348                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 349                 child->exit_code = data;
 350                 /* make sure the single step bit is not set. */
 351                 clear_single_step(child);
 352                 wake_up_process(child);
 353                 ret = 0;
 354                 break;
 355         }
 356
 357 /*
 358  * make the child exit.  Best I can do is send it a sigkill.
 359  * perhaps it should be put in the status that it wants to
 360  * exit.
 361  */
 362         case PTRACE_KILL: {
 363                 ret = 0;
 364                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 365                         break;
 366                 child->exit_code = SIGKILL;
 367                 /* make sure the single step bit is not set. */
 368                 clear_single_step(child);
 369                 wake_up_process(child);
 370                 break;
 371         }
 372
 373         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 374                 ret = -EIO;
 375                 if (!valid_signal(data))
 376                         break;
 377                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 378                 set_single_step(child);
 379                 child->exit_code = data;
 380                 /* give it a chance to run. */
 381                 wake_up_process(child);
 382                 ret = 0;
 383                 break;
 384         }
 385
 386 #ifdef CONFIG_PPC64
 387         case PTRACE_GET_DEBUGREG: {
 388                 ret = -EINVAL;
 389                 /* We only support one DABR and no IABRS at the moment */
 390                 if (addr > 0)
 391                         break;
 392                 ret = put_user(child->thread.dabr,
 393                                (unsigned long __user *)data);
 394                 break;
 395         }
 396
 397         case PTRACE_SET_DEBUGREG:
 398                 ret = ptrace_set_debugreg(child, addr, data);
 399                 break;
 400 #endif
 401
 402         case PTRACE_DETACH:
 403                 ret = ptrace_detach(child, data);
 404                 break;
 405
 406         case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
 407                 int i;
 408                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 409                 unsigned long __user *tmp = (unsigned long __user *)addr;
 410
 411                 for (i = 0; i < 32; i++) {
 412                         ret = put_user(*reg, tmp);
 413                         if (ret)
 414                                 break;
 415                         reg++;
 416                         tmp++;
 417                 }
 418                 break;
 419         }
 420
 421         case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
 422                 int i;
 423                 unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
 424                 unsigned long __user *tmp = (unsigned long __user *)addr;
 425
 426                 for (i = 0; i < 32; i++) {
 427                         ret = get_user(*reg, tmp);
 428                         if (ret)
 429                                 break;
 430                         reg++;
 431                         tmp++;
 432                 }
 433                 break;
 434         }
 435
 436         case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
 437                 int i;
 438                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 439                 unsigned long __user *tmp = (unsigned long __user *)addr;
 440
 441                 flush_fp_to_thread(child);
 442
 443                 for (i = 0; i < 32; i++) {
 444                         ret = put_user(*reg, tmp);
 445                         if (ret)
 446                                 break;
 447                         reg++;
 448                         tmp++;
 449                 }
 450                 break;
 451         }
 452
 453         case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
 454                 int i;
 455                 unsigned long *reg = &((unsigned long *)child->thread.fpr)[0];
 456                 unsigned long __user *tmp = (unsigned long __user *)addr;
 457
 458                 flush_fp_to_thread(child);
 459
 460                 for (i = 0; i < 32; i++) {
 461                         ret = get_user(*reg, tmp);
 462                         if (ret)
 463                                 break;
 464                         reg++;
 465                         tmp++;
 466                 }
 467                 break;
 468         }
 469
 470 #ifdef CONFIG_ALTIVEC
 471         case PTRACE_GETVRREGS:
 472                 /* Get the child altivec register state. */
 473                 flush_altivec_to_thread(child);
 474                 ret = get_vrregs((unsigned long __user *)data, child);
 475                 break;
 476
 477         case PTRACE_SETVRREGS:
 478                 /* Set the child altivec register state. */
 479                 flush_altivec_to_thread(child);
 480                 ret = set_vrregs(child, (unsigned long __user *)data);
 481                 break;
 482 #endif
 483 #ifdef CONFIG_SPE
 484         case PTRACE_GETEVRREGS:
 485                 /* Get the child spe register state. */
 486                 if (child->thread.regs->msr & MSR_SPE)
 487                         giveup_spe(child);
 488                 ret = get_evrregs((unsigned long __user *)data, child);
 489                 break;
 490
 491         case PTRACE_SETEVRREGS:
 492                 /* Set the child spe register state. */
 493                 /* this is to clear the MSR_SPE bit to force a reload
 494                  * of register state from memory */
 495                 if (child->thread.regs->msr & MSR_SPE)
 496                         giveup_spe(child);
 497                 ret = set_evrregs(child, (unsigned long __user *)data);
 498                 break;
 499 #endif
 500
 501         default:
 502                 ret = ptrace_request(child, request, addr, data);
 503                 break;
 504         }
 505
 506         return ret;
 507 }
 508
 509 static void do_syscall_trace(void)
 510 {
 511         /* the 0x80 provides a way for the tracing parent to distinguish
 512            between a syscall stop and SIGTRAP delivery */
 513         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 514                                  ? 0x80 : 0));
 515
 516         /*
 517          * this isn't the same as continuing with a signal, but it will do
 518          * for normal use.  strace only continues with a signal if the
 519          * stopping signal is not SIGTRAP.  -brl
 520          */
 521         if (current->exit_code) {
 522                 send_sig(current->exit_code, current, 1);
 523                 current->exit_code = 0;
 524         }
 525 }
 526
 527 void do_syscall_trace_enter(struct pt_regs *regs)
 528 {
 529 #ifdef CONFIG_PPC64
 530         secure_computing(regs->gpr[0]);
 531 #endif
 532
 533         if (test_thread_flag(TIF_SYSCALL_TRACE)
 534             && (current->ptrace & PT_PTRACED))
 535                 do_syscall_trace();
 536
 537         if (unlikely(current->audit_context))
 538                 audit_syscall_entry(
 539 #ifdef CONFIG_PPC32
 540                                     AUDIT_ARCH_PPC,
 541 #else
 542                                     test_thread_flag(TIF_32BIT)?AUDIT_ARCH_PPC:AUDIT_ARCH_PPC64,
 543 #endif
 544                                     regs->gpr[0],
 545                                     regs->gpr[3], regs->gpr[4],
 546                                     regs->gpr[5], regs->gpr[6]);
 547 }
 548
 549 void do_syscall_trace_leave(struct pt_regs *regs)
 550 {
 551 #ifdef CONFIG_PPC32
 552         secure_computing(regs->gpr[0]);
 553 #endif
 554
 555         if (unlikely(current->audit_context))
 556                 audit_syscall_exit((regs->ccr&0x1000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,
 557                                    regs->result);
 558
 559         if ((test_thread_flag(TIF_SYSCALL_TRACE)
 560              || test_thread_flag(TIF_SINGLESTEP))
 561             && (current->ptrace & PT_PTRACED))
 562                 do_syscall_trace();
 563 }
 564
 565 #ifdef CONFIG_PPC32
 566 EXPORT_SYMBOL(do_syscall_trace_enter);
 567 EXPORT_SYMBOL(do_syscall_trace_leave);
 568 #endif