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