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