arch/mips/kernel/ptrace.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1992 Ross Biro
   7  * Copyright (C) Linus Torvalds
   8  * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
   9  * Copyright (C) 1996 David S. Miller
  10  * Kevin D. Kissell, [email protected] and Carsten Langgaard, [email protected]
  11  * Copyright (C) 1999 MIPS Technologies, Inc.
  12  * Copyright (C) 2000 Ulf Carlsson
  13  *
  14  * At this time Linux/MIPS64 only supports syscall tracing, even for 32-bit
  15  * binaries.
  16  */
  17 #include <linux/compiler.h>
  18 #include <linux/context_tracking.h>
  19 #include <linux/kernel.h>
  20 #include <linux/sched.h>
  21 #include <linux/mm.h>
  22 #include <linux/errno.h>
  23 #include <linux/ptrace.h>
  24 #include <linux/smp.h>
  25 #include <linux/user.h>
  26 #include <linux/security.h>
  27 #include <linux/audit.h>
  28 #include <linux/seccomp.h>
  29
  30 #include <asm/byteorder.h>
  31 #include <asm/cpu.h>
  32 #include <asm/dsp.h>
  33 #include <asm/fpu.h>
  34 #include <asm/mipsregs.h>
  35 #include <asm/mipsmtregs.h>
  36 #include <asm/pgtable.h>
  37 #include <asm/page.h>
  38 #include <asm/uaccess.h>
  39 #include <asm/bootinfo.h>
  40 #include <asm/reg.h>
  41
  42 /*
  43  * Called by kernel/ptrace.c when detaching..
  44  *
  45  * Make sure single step bits etc are not set.
  46  */
  47 void ptrace_disable(struct task_struct *child)
  48 {
  49         /* Don't load the watchpoint registers for the ex-child. */
  50         clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
  51 }
  52
  53 /*
  54  * Read a general register set.  We always use the 64-bit format, even
  55  * for 32-bit kernels and for 32-bit processes on a 64-bit kernel.
  56  * Registers are sign extended to fill the available space.
  57  */
  58 int ptrace_getregs(struct task_struct *child, __s64 __user *data)
  59 {
  60         struct pt_regs *regs;
  61         int i;
  62
  63         if (!access_ok(VERIFY_WRITE, data, 38 * 8))
  64                 return -EIO;
  65
  66         regs = task_pt_regs(child);
  67
  68         for (i = 0; i < 32; i++)
  69                 __put_user((long)regs->regs[i], data + i);
  70         __put_user((long)regs->lo, data + EF_LO - EF_R0);
  71         __put_user((long)regs->hi, data + EF_HI - EF_R0);
  72         __put_user((long)regs->cp0_epc, data + EF_CP0_EPC - EF_R0);
  73         __put_user((long)regs->cp0_badvaddr, data + EF_CP0_BADVADDR - EF_R0);
  74         __put_user((long)regs->cp0_status, data + EF_CP0_STATUS - EF_R0);
  75         __put_user((long)regs->cp0_cause, data + EF_CP0_CAUSE - EF_R0);
  76
  77         return 0;
  78 }
  79
  80 /*
  81  * Write a general register set.  As for PTRACE_GETREGS, we always use
  82  * the 64-bit format.  On a 32-bit kernel only the lower order half
  83  * (according to endianness) will be used.
  84  */
  85 int ptrace_setregs(struct task_struct *child, __s64 __user *data)
  86 {
  87         struct pt_regs *regs;
  88         int i;
  89
  90         if (!access_ok(VERIFY_READ, data, 38 * 8))
  91                 return -EIO;
  92
  93         regs = task_pt_regs(child);
  94
  95         for (i = 0; i < 32; i++)
  96                 __get_user(regs->regs[i], data + i);
  97         __get_user(regs->lo, data + EF_LO - EF_R0);
  98         __get_user(regs->hi, data + EF_HI - EF_R0);
  99         __get_user(regs->cp0_epc, data + EF_CP0_EPC - EF_R0);
 100
 101         /* badvaddr, status, and cause may not be written.  */
 102
 103         return 0;
 104 }
 105
 106 int ptrace_getfpregs(struct task_struct *child, __u32 __user *data)
 107 {
 108         int i;
 109         unsigned int tmp;
 110
 111         if (!access_ok(VERIFY_WRITE, data, 33 * 8))
 112                 return -EIO;
 113
 114         if (tsk_used_math(child)) {
 115                 fpureg_t *fregs = get_fpu_regs(child);
 116                 for (i = 0; i < 32; i++)
 117                         __put_user(fregs[i], i + (__u64 __user *) data);
 118         } else {
 119                 for (i = 0; i < 32; i++)
 120                         __put_user((__u64) -1, i + (__u64 __user *) data);
 121         }
 122
 123         __put_user(child->thread.fpu.fcr31, data + 64);
 124
 125         preempt_disable();
 126         if (cpu_has_fpu) {
 127                 unsigned int flags;
 128
 129                 if (cpu_has_mipsmt) {
 130                         unsigned int vpflags = dvpe();
 131                         flags = read_c0_status();
 132                         __enable_fpu();
 133                         __asm__ __volatile__("cfc1\t%0,$0" : "=r" (tmp));
 134                         write_c0_status(flags);
 135                         evpe(vpflags);
 136                 } else {
 137                         flags = read_c0_status();
 138                         __enable_fpu();
 139                         __asm__ __volatile__("cfc1\t%0,$0" : "=r" (tmp));
 140                         write_c0_status(flags);
 141                 }
 142         } else {
 143                 tmp = 0;
 144         }
 145         preempt_enable();
 146         __put_user(tmp, data + 65);
 147
 148         return 0;
 149 }
 150
 151 int ptrace_setfpregs(struct task_struct *child, __u32 __user *data)
 152 {
 153         fpureg_t *fregs;
 154         int i;
 155
 156         if (!access_ok(VERIFY_READ, data, 33 * 8))
 157                 return -EIO;
 158
 159         fregs = get_fpu_regs(child);
 160
 161         for (i = 0; i < 32; i++)
 162                 __get_user(fregs[i], i + (__u64 __user *) data);
 163
 164         __get_user(child->thread.fpu.fcr31, data + 64);
 165
 166         /* FIR may not be written.  */
 167
 168         return 0;
 169 }
 170
 171 int ptrace_get_watch_regs(struct task_struct *child,
 172                           struct pt_watch_regs __user *addr)
 173 {
 174         enum pt_watch_style style;
 175         int i;
 176
 177         if (!cpu_has_watch || current_cpu_data.watch_reg_use_cnt == 0)
 178                 return -EIO;
 179         if (!access_ok(VERIFY_WRITE, addr, sizeof(struct pt_watch_regs)))
 180                 return -EIO;
 181
 182 #ifdef CONFIG_32BIT
 183         style = pt_watch_style_mips32;
 184 #define WATCH_STYLE mips32
 185 #else
 186         style = pt_watch_style_mips64;
 187 #define WATCH_STYLE mips64
 188 #endif
 189
 190         __put_user(style, &addr->style);
 191         __put_user(current_cpu_data.watch_reg_use_cnt,
 192                    &addr->WATCH_STYLE.num_valid);
 193         for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
 194                 __put_user(child->thread.watch.mips3264.watchlo[i],
 195                            &addr->WATCH_STYLE.watchlo[i]);
 196                 __put_user(child->thread.watch.mips3264.watchhi[i] & 0xfff,
 197                            &addr->WATCH_STYLE.watchhi[i]);
 198                 __put_user(current_cpu_data.watch_reg_masks[i],
 199                            &addr->WATCH_STYLE.watch_masks[i]);
 200         }
 201         for (; i < 8; i++) {
 202                 __put_user(0, &addr->WATCH_STYLE.watchlo[i]);
 203                 __put_user(0, &addr->WATCH_STYLE.watchhi[i]);
 204                 __put_user(0, &addr->WATCH_STYLE.watch_masks[i]);
 205         }
 206
 207         return 0;
 208 }
 209
 210 int ptrace_set_watch_regs(struct task_struct *child,
 211                           struct pt_watch_regs __user *addr)
 212 {
 213         int i;
 214         int watch_active = 0;
 215         unsigned long lt[NUM_WATCH_REGS];
 216         u16 ht[NUM_WATCH_REGS];
 217
 218         if (!cpu_has_watch || current_cpu_data.watch_reg_use_cnt == 0)
 219                 return -EIO;
 220         if (!access_ok(VERIFY_READ, addr, sizeof(struct pt_watch_regs)))
 221                 return -EIO;
 222         /* Check the values. */
 223         for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
 224                 __get_user(lt[i], &addr->WATCH_STYLE.watchlo[i]);
 225 #ifdef CONFIG_32BIT
 226                 if (lt[i] & __UA_LIMIT)
 227                         return -EINVAL;
 228 #else
 229                 if (test_tsk_thread_flag(child, TIF_32BIT_ADDR)) {
 230                         if (lt[i] & 0xffffffff80000000UL)
 231                                 return -EINVAL;
 232                 } else {
 233                         if (lt[i] & __UA_LIMIT)
 234                                 return -EINVAL;
 235                 }
 236 #endif
 237                 __get_user(ht[i], &addr->WATCH_STYLE.watchhi[i]);
 238                 if (ht[i] & ~0xff8)
 239                         return -EINVAL;
 240         }
 241         /* Install them. */
 242         for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
 243                 if (lt[i] & 7)
 244                         watch_active = 1;
 245                 child->thread.watch.mips3264.watchlo[i] = lt[i];
 246                 /* Set the G bit. */
 247                 child->thread.watch.mips3264.watchhi[i] = ht[i];
 248         }
 249
 250         if (watch_active)
 251                 set_tsk_thread_flag(child, TIF_LOAD_WATCH);
 252         else
 253                 clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
 254
 255         return 0;
 256 }
 257
 258 long arch_ptrace(struct task_struct *child, long request,
 259                  unsigned long addr, unsigned long data)
 260 {
 261         int ret;
 262         void __user *addrp = (void __user *) addr;
 263         void __user *datavp = (void __user *) data;
 264         unsigned long __user *datalp = (void __user *) data;
 265
 266         switch (request) {
 267         /* when I and D space are separate, these will need to be fixed. */
 268         case PTRACE_PEEKTEXT: /* read word at location addr. */
 269         case PTRACE_PEEKDATA:
 270                 ret = generic_ptrace_peekdata(child, addr, data);
 271                 break;
 272
 273         /* Read the word at location addr in the USER area. */
 274         case PTRACE_PEEKUSR: {
 275                 struct pt_regs *regs;
 276                 unsigned long tmp = 0;
 277
 278                 regs = task_pt_regs(child);
 279                 ret = 0;  /* Default return value. */
 280
 281                 switch (addr) {
 282                 case 0 ... 31:
 283                         tmp = regs->regs[addr];
 284                         break;
 285                 case FPR_BASE ... FPR_BASE + 31:
 286                         if (tsk_used_math(child)) {
 287                                 fpureg_t *fregs = get_fpu_regs(child);
 288
 289 #ifdef CONFIG_32BIT
 290                                 /*
 291                                  * The odd registers are actually the high
 292                                  * order bits of the values stored in the even
 293                                  * registers - unless we're using r2k_switch.S.
 294                                  */
 295                                 if (addr & 1)
 296                                         tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
 297                                 else
 298                                         tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
 299 #endif
 300 #ifdef CONFIG_64BIT
 301                                 tmp = fregs[addr - FPR_BASE];
 302 #endif
 303                         } else {
 304                                 tmp = -1;       /* FP not yet used  */
 305                         }
 306                         break;
 307                 case PC:
 308                         tmp = regs->cp0_epc;
 309                         break;
 310                 case CAUSE:
 311                         tmp = regs->cp0_cause;
 312                         break;
 313                 case BADVADDR:
 314                         tmp = regs->cp0_badvaddr;
 315                         break;
 316                 case MMHI:
 317                         tmp = regs->hi;
 318                         break;
 319                 case MMLO:
 320                         tmp = regs->lo;
 321                         break;
 322 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 323                 case ACX:
 324                         tmp = regs->acx;
 325                         break;
 326 #endif
 327                 case FPC_CSR:
 328                         tmp = child->thread.fpu.fcr31;
 329                         break;
 330                 case FPC_EIR: { /* implementation / version register */
 331                         unsigned int flags;
 332 #ifdef CONFIG_MIPS_MT_SMTC
 333                         unsigned long irqflags;
 334                         unsigned int mtflags;
 335 #endif /* CONFIG_MIPS_MT_SMTC */
 336
 337                         preempt_disable();
 338                         if (!cpu_has_fpu) {
 339                                 preempt_enable();
 340                                 break;
 341                         }
 342
 343 #ifdef CONFIG_MIPS_MT_SMTC
 344                         /* Read-modify-write of Status must be atomic */
 345                         local_irq_save(irqflags);
 346                         mtflags = dmt();
 347 #endif /* CONFIG_MIPS_MT_SMTC */
 348                         if (cpu_has_mipsmt) {
 349                                 unsigned int vpflags = dvpe();
 350                                 flags = read_c0_status();
 351                                 __enable_fpu();
 352                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 353                                 write_c0_status(flags);
 354                                 evpe(vpflags);
 355                         } else {
 356                                 flags = read_c0_status();
 357                                 __enable_fpu();
 358                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 359                                 write_c0_status(flags);
 360                         }
 361 #ifdef CONFIG_MIPS_MT_SMTC
 362                         emt(mtflags);
 363                         local_irq_restore(irqflags);
 364 #endif /* CONFIG_MIPS_MT_SMTC */
 365                         preempt_enable();
 366                         break;
 367                 }
 368                 case DSP_BASE ... DSP_BASE + 5: {
 369                         dspreg_t *dregs;
 370
 371                         if (!cpu_has_dsp) {
 372                                 tmp = 0;
 373                                 ret = -EIO;
 374                                 goto out;
 375                         }
 376                         dregs = __get_dsp_regs(child);
 377                         tmp = (unsigned long) (dregs[addr - DSP_BASE]);
 378                         break;
 379                 }
 380                 case DSP_CONTROL:
 381                         if (!cpu_has_dsp) {
 382                                 tmp = 0;
 383                                 ret = -EIO;
 384                                 goto out;
 385                         }
 386                         tmp = child->thread.dsp.dspcontrol;
 387                         break;
 388                 default:
 389                         tmp = 0;
 390                         ret = -EIO;
 391                         goto out;
 392                 }
 393                 ret = put_user(tmp, datalp);
 394                 break;
 395         }
 396
 397         /* when I and D space are separate, this will have to be fixed. */
 398         case PTRACE_POKETEXT: /* write the word at location addr. */
 399         case PTRACE_POKEDATA:
 400                 ret = generic_ptrace_pokedata(child, addr, data);
 401                 break;
 402
 403         case PTRACE_POKEUSR: {
 404                 struct pt_regs *regs;
 405                 ret = 0;
 406                 regs = task_pt_regs(child);
 407
 408                 switch (addr) {
 409                 case 0 ... 31:
 410                         regs->regs[addr] = data;
 411                         break;
 412                 case FPR_BASE ... FPR_BASE + 31: {
 413                         fpureg_t *fregs = get_fpu_regs(child);
 414
 415                         if (!tsk_used_math(child)) {
 416                                 /* FP not yet used  */
 417                                 memset(&child->thread.fpu, ~0,
 418                                        sizeof(child->thread.fpu));
 419                                 child->thread.fpu.fcr31 = 0;
 420                         }
 421 #ifdef CONFIG_32BIT
 422                         /*
 423                          * The odd registers are actually the high order bits
 424                          * of the values stored in the even registers - unless
 425                          * we're using r2k_switch.S.
 426                          */
 427                         if (addr & 1) {
 428                                 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
 429                                 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
 430                         } else {
 431                                 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
 432                                 fregs[addr - FPR_BASE] |= data;
 433                         }
 434 #endif
 435 #ifdef CONFIG_64BIT
 436                         fregs[addr - FPR_BASE] = data;
 437 #endif
 438                         break;
 439                 }
 440                 case PC:
 441                         regs->cp0_epc = data;
 442                         break;
 443                 case MMHI:
 444                         regs->hi = data;
 445                         break;
 446                 case MMLO:
 447                         regs->lo = data;
 448                         break;
 449 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 450                 case ACX:
 451                         regs->acx = data;
 452                         break;
 453 #endif
 454                 case FPC_CSR:
 455                         child->thread.fpu.fcr31 = data;
 456                         break;
 457                 case DSP_BASE ... DSP_BASE + 5: {
 458                         dspreg_t *dregs;
 459
 460                         if (!cpu_has_dsp) {
 461                                 ret = -EIO;
 462                                 break;
 463                         }
 464
 465                         dregs = __get_dsp_regs(child);
 466                         dregs[addr - DSP_BASE] = data;
 467                         break;
 468                 }
 469                 case DSP_CONTROL:
 470                         if (!cpu_has_dsp) {
 471                                 ret = -EIO;
 472                                 break;
 473                         }
 474                         child->thread.dsp.dspcontrol = data;
 475                         break;
 476                 default:
 477                         /* The rest are not allowed. */
 478                         ret = -EIO;
 479                         break;
 480                 }
 481                 break;
 482                 }
 483
 484         case PTRACE_GETREGS:
 485                 ret = ptrace_getregs(child, datavp);
 486                 break;
 487
 488         case PTRACE_SETREGS:
 489                 ret = ptrace_setregs(child, datavp);
 490                 break;
 491
 492         case PTRACE_GETFPREGS:
 493                 ret = ptrace_getfpregs(child, datavp);
 494                 break;
 495
 496         case PTRACE_SETFPREGS:
 497                 ret = ptrace_setfpregs(child, datavp);
 498                 break;
 499
 500         case PTRACE_GET_THREAD_AREA:
 501                 ret = put_user(task_thread_info(child)->tp_value, datalp);
 502                 break;
 503
 504         case PTRACE_GET_WATCH_REGS:
 505                 ret = ptrace_get_watch_regs(child, addrp);
 506                 break;
 507
 508         case PTRACE_SET_WATCH_REGS:
 509                 ret = ptrace_set_watch_regs(child, addrp);
 510                 break;
 511
 512         default:
 513                 ret = ptrace_request(child, request, addr, data);
 514                 break;
 515         }
 516  out:
 517         return ret;
 518 }
 519
 520 static inline int audit_arch(void)
 521 {
 522         int arch = EM_MIPS;
 523 #ifdef CONFIG_64BIT
 524         arch |=  __AUDIT_ARCH_64BIT;
 525 #endif
 526 #if defined(__LITTLE_ENDIAN)
 527         arch |=  __AUDIT_ARCH_LE;
 528 #endif
 529         return arch;
 530 }
 531
 532 /*
 533  * Notification of system call entry/exit
 534  * - triggered by current->work.syscall_trace
 535  */
 536 asmlinkage void syscall_trace_enter(struct pt_regs *regs)
 537 {
 538         user_exit();
 539
 540         /* do the secure computing check first */
 541         secure_computing_strict(regs->regs[2]);
 542
 543         if (!(current->ptrace & PT_PTRACED))
 544                 goto out;
 545
 546         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 547                 goto out;
 548
 549         /* The 0x80 provides a way for the tracing parent to distinguish
 550            between a syscall stop and SIGTRAP delivery */
 551         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
 552                                  0x80 : 0));
 553
 554         /*
 555          * this isn't the same as continuing with a signal, but it will do
 556          * for normal use.  strace only continues with a signal if the
 557          * stopping signal is not SIGTRAP.  -brl
 558          */
 559         if (current->exit_code) {
 560                 send_sig(current->exit_code, current, 1);
 561                 current->exit_code = 0;
 562         }
 563
 564 out:
 565         audit_syscall_entry(audit_arch(), regs->regs[2],
 566                             regs->regs[4], regs->regs[5],
 567                             regs->regs[6], regs->regs[7]);
 568 }
 569
 570 /*
 571  * Notification of system call entry/exit
 572  * - triggered by current->work.syscall_trace
 573  */
 574 asmlinkage void syscall_trace_leave(struct pt_regs *regs)
 575 {
 576         /*
 577          * We may come here right after calling schedule_user()
 578          * or do_notify_resume(), in which case we can be in RCU
 579          * user mode.
 580          */
 581         user_exit();
 582
 583         audit_syscall_exit(regs);
 584
 585         if (!(current->ptrace & PT_PTRACED))
 586                 return;
 587
 588         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 589                 return;
 590
 591         /* The 0x80 provides a way for the tracing parent to distinguish
 592            between a syscall stop and SIGTRAP delivery */
 593         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
 594                                  0x80 : 0));
 595
 596         /*
 597          * this isn't the same as continuing with a signal, but it will do
 598          * for normal use.  strace only continues with a signal if the
 599          * stopping signal is not SIGTRAP.  -brl
 600          */
 601         if (current->exit_code) {
 602                 send_sig(current->exit_code, current, 1);
 603                 current->exit_code = 0;
 604         }
 605
 606         user_enter();
 607 }