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, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
  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/kernel.h>
  19 #include <linux/sched.h>
  20 #include <linux/mm.h>
  21 #include <linux/errno.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/audit.h>
  24 #include <linux/smp.h>
  25 #include <linux/user.h>
  26 #include <linux/security.h>
  27 #include <linux/signal.h>
  28
  29 #include <asm/byteorder.h>
  30 #include <asm/cpu.h>
  31 #include <asm/dsp.h>
  32 #include <asm/fpu.h>
  33 #include <asm/mipsregs.h>
  34 #include <asm/mipsmtregs.h>
  35 #include <asm/pgtable.h>
  36 #include <asm/page.h>
  37 #include <asm/system.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         /* Nothing to do.. */
  50 }
  51
  52 /*
  53  * Read a general register set.  We always use the 64-bit format, even
  54  * for 32-bit kernels and for 32-bit processes on a 64-bit kernel.
  55  * Registers are sign extended to fill the available space.
  56  */
  57 int ptrace_getregs (struct task_struct *child, __s64 __user *data)
  58 {
  59         struct pt_regs *regs;
  60         int i;
  61
  62         if (!access_ok(VERIFY_WRITE, data, 38 * 8))
  63                 return -EIO;
  64
  65         regs = task_pt_regs(child);
  66
  67         for (i = 0; i < 32; i++)
  68                 __put_user (regs->regs[i], data + i);
  69         __put_user (regs->lo, data + EF_LO - EF_R0);
  70         __put_user (regs->hi, data + EF_HI - EF_R0);
  71         __put_user (regs->cp0_epc, data + EF_CP0_EPC - EF_R0);
  72         __put_user (regs->cp0_badvaddr, data + EF_CP0_BADVADDR - EF_R0);
  73         __put_user (regs->cp0_status, data + EF_CP0_STATUS - EF_R0);
  74         __put_user (regs->cp0_cause, data + EF_CP0_CAUSE - EF_R0);
  75
  76         return 0;
  77 }
  78
  79 /*
  80  * Write a general register set.  As for PTRACE_GETREGS, we always use
  81  * the 64-bit format.  On a 32-bit kernel only the lower order half
  82  * (according to endianness) will be used.
  83  */
  84 int ptrace_setregs (struct task_struct *child, __s64 __user *data)
  85 {
  86         struct pt_regs *regs;
  87         int i;
  88
  89         if (!access_ok(VERIFY_READ, data, 38 * 8))
  90                 return -EIO;
  91
  92         regs = task_pt_regs(child);
  93
  94         for (i = 0; i < 32; i++)
  95                 __get_user (regs->regs[i], data + i);
  96         __get_user (regs->lo, data + EF_LO - EF_R0);
  97         __get_user (regs->hi, data + EF_HI - EF_R0);
  98         __get_user (regs->cp0_epc, data + EF_CP0_EPC - EF_R0);
  99
 100         /* badvaddr, status, and cause may not be written.  */
 101
 102         return 0;
 103 }
 104
 105 int ptrace_getfpregs (struct task_struct *child, __u32 __user *data)
 106 {
 107         int i;
 108         unsigned int tmp;
 109
 110         if (!access_ok(VERIFY_WRITE, data, 33 * 8))
 111                 return -EIO;
 112
 113         if (tsk_used_math(child)) {
 114                 fpureg_t *fregs = get_fpu_regs(child);
 115                 for (i = 0; i < 32; i++)
 116                         __put_user (fregs[i], i + (__u64 __user *) data);
 117         } else {
 118                 for (i = 0; i < 32; i++)
 119                         __put_user ((__u64) -1, i + (__u64 __user *) data);
 120         }
 121
 122         __put_user (child->thread.fpu.fcr31, data + 64);
 123
 124         preempt_disable();
 125         if (cpu_has_fpu) {
 126                 unsigned int flags;
 127
 128                 if (cpu_has_mipsmt) {
 129                         unsigned int vpflags = dvpe();
 130                         flags = read_c0_status();
 131                         __enable_fpu();
 132                         __asm__ __volatile__("cfc1\t%0,$0" : "=r" (tmp));
 133                         write_c0_status(flags);
 134                         evpe(vpflags);
 135                 } else {
 136                         flags = read_c0_status();
 137                         __enable_fpu();
 138                         __asm__ __volatile__("cfc1\t%0,$0" : "=r" (tmp));
 139                         write_c0_status(flags);
 140                 }
 141         } else {
 142                 tmp = 0;
 143         }
 144         preempt_enable();
 145         __put_user (tmp, data + 65);
 146
 147         return 0;
 148 }
 149
 150 int ptrace_setfpregs (struct task_struct *child, __u32 __user *data)
 151 {
 152         fpureg_t *fregs;
 153         int i;
 154
 155         if (!access_ok(VERIFY_READ, data, 33 * 8))
 156                 return -EIO;
 157
 158         fregs = get_fpu_regs(child);
 159
 160         for (i = 0; i < 32; i++)
 161                 __get_user (fregs[i], i + (__u64 __user *) data);
 162
 163         __get_user (child->thread.fpu.fcr31, data + 64);
 164
 165         /* FIR may not be written.  */
 166
 167         return 0;
 168 }
 169
 170 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 171 {
 172         int ret;
 173
 174         switch (request) {
 175         /* when I and D space are separate, these will need to be fixed. */
 176         case PTRACE_PEEKTEXT: /* read word at location addr. */
 177         case PTRACE_PEEKDATA: {
 178                 unsigned long tmp;
 179                 int copied;
 180
 181                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 182                 ret = -EIO;
 183                 if (copied != sizeof(tmp))
 184                         break;
 185                 ret = put_user(tmp,(unsigned long __user *) data);
 186                 break;
 187         }
 188
 189         /* Read the word at location addr in the USER area. */
 190         case PTRACE_PEEKUSR: {
 191                 struct pt_regs *regs;
 192                 unsigned long tmp = 0;
 193
 194                 regs = task_pt_regs(child);
 195                 ret = 0;  /* Default return value. */
 196
 197                 switch (addr) {
 198                 case 0 ... 31:
 199                         tmp = regs->regs[addr];
 200                         break;
 201                 case FPR_BASE ... FPR_BASE + 31:
 202                         if (tsk_used_math(child)) {
 203                                 fpureg_t *fregs = get_fpu_regs(child);
 204
 205 #ifdef CONFIG_32BIT
 206                                 /*
 207                                  * The odd registers are actually the high
 208                                  * order bits of the values stored in the even
 209                                  * registers - unless we're using r2k_switch.S.
 210                                  */
 211                                 if (addr & 1)
 212                                         tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
 213                                 else
 214                                         tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
 215 #endif
 216 #ifdef CONFIG_64BIT
 217                                 tmp = fregs[addr - FPR_BASE];
 218 #endif
 219                         } else {
 220                                 tmp = -1;       /* FP not yet used  */
 221                         }
 222                         break;
 223                 case PC:
 224                         tmp = regs->cp0_epc;
 225                         break;
 226                 case CAUSE:
 227                         tmp = regs->cp0_cause;
 228                         break;
 229                 case BADVADDR:
 230                         tmp = regs->cp0_badvaddr;
 231                         break;
 232                 case MMHI:
 233                         tmp = regs->hi;
 234                         break;
 235                 case MMLO:
 236                         tmp = regs->lo;
 237                         break;
 238 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 239                 case ACX:
 240                         tmp = regs->acx;
 241                         break;
 242 #endif
 243                 case FPC_CSR:
 244                         tmp = child->thread.fpu.fcr31;
 245                         break;
 246                 case FPC_EIR: { /* implementation / version register */
 247                         unsigned int flags;
 248 #ifdef CONFIG_MIPS_MT_SMTC
 249                         unsigned int irqflags;
 250                         unsigned int mtflags;
 251 #endif /* CONFIG_MIPS_MT_SMTC */
 252
 253                         preempt_disable();
 254                         if (!cpu_has_fpu) {
 255                                 preempt_enable();
 256                                 break;
 257                         }
 258
 259 #ifdef CONFIG_MIPS_MT_SMTC
 260                         /* Read-modify-write of Status must be atomic */
 261                         local_irq_save(irqflags);
 262                         mtflags = dmt();
 263 #endif /* CONFIG_MIPS_MT_SMTC */
 264                         if (cpu_has_mipsmt) {
 265                                 unsigned int vpflags = dvpe();
 266                                 flags = read_c0_status();
 267                                 __enable_fpu();
 268                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 269                                 write_c0_status(flags);
 270                                 evpe(vpflags);
 271                         } else {
 272                                 flags = read_c0_status();
 273                                 __enable_fpu();
 274                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 275                                 write_c0_status(flags);
 276                         }
 277 #ifdef CONFIG_MIPS_MT_SMTC
 278                         emt(mtflags);
 279                         local_irq_restore(irqflags);
 280 #endif /* CONFIG_MIPS_MT_SMTC */
 281                         preempt_enable();
 282                         break;
 283                 }
 284                 case DSP_BASE ... DSP_BASE + 5: {
 285                         dspreg_t *dregs;
 286
 287                         if (!cpu_has_dsp) {
 288                                 tmp = 0;
 289                                 ret = -EIO;
 290                                 goto out;
 291                         }
 292                         dregs = __get_dsp_regs(child);
 293                         tmp = (unsigned long) (dregs[addr - DSP_BASE]);
 294                         break;
 295                 }
 296                 case DSP_CONTROL:
 297                         if (!cpu_has_dsp) {
 298                                 tmp = 0;
 299                                 ret = -EIO;
 300                                 goto out;
 301                         }
 302                         tmp = child->thread.dsp.dspcontrol;
 303                         break;
 304                 default:
 305                         tmp = 0;
 306                         ret = -EIO;
 307                         goto out;
 308                 }
 309                 ret = put_user(tmp, (unsigned long __user *) data);
 310                 break;
 311         }
 312
 313         /* when I and D space are separate, this will have to be fixed. */
 314         case PTRACE_POKETEXT: /* write the word at location addr. */
 315         case PTRACE_POKEDATA:
 316                 ret = 0;
 317                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 318                     == sizeof(data))
 319                         break;
 320                 ret = -EIO;
 321                 break;
 322
 323         case PTRACE_POKEUSR: {
 324                 struct pt_regs *regs;
 325                 ret = 0;
 326                 regs = task_pt_regs(child);
 327
 328                 switch (addr) {
 329                 case 0 ... 31:
 330                         regs->regs[addr] = data;
 331                         break;
 332                 case FPR_BASE ... FPR_BASE + 31: {
 333                         fpureg_t *fregs = get_fpu_regs(child);
 334
 335                         if (!tsk_used_math(child)) {
 336                                 /* FP not yet used  */
 337                                 memset(&child->thread.fpu, ~0,
 338                                        sizeof(child->thread.fpu));
 339                                 child->thread.fpu.fcr31 = 0;
 340                         }
 341 #ifdef CONFIG_32BIT
 342                         /*
 343                          * The odd registers are actually the high order bits
 344                          * of the values stored in the even registers - unless
 345                          * we're using r2k_switch.S.
 346                          */
 347                         if (addr & 1) {
 348                                 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
 349                                 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
 350                         } else {
 351                                 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
 352                                 fregs[addr - FPR_BASE] |= data;
 353                         }
 354 #endif
 355 #ifdef CONFIG_64BIT
 356                         fregs[addr - FPR_BASE] = data;
 357 #endif
 358                         break;
 359                 }
 360                 case PC:
 361                         regs->cp0_epc = data;
 362                         break;
 363                 case MMHI:
 364                         regs->hi = data;
 365                         break;
 366                 case MMLO:
 367                         regs->lo = data;
 368                         break;
 369 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 370                 case ACX:
 371                         regs->acx = data;
 372                         break;
 373 #endif
 374                 case FPC_CSR:
 375                         child->thread.fpu.fcr31 = data;
 376                         break;
 377                 case DSP_BASE ... DSP_BASE + 5: {
 378                         dspreg_t *dregs;
 379
 380                         if (!cpu_has_dsp) {
 381                                 ret = -EIO;
 382                                 break;
 383                         }
 384
 385                         dregs = __get_dsp_regs(child);
 386                         dregs[addr - DSP_BASE] = data;
 387                         break;
 388                 }
 389                 case DSP_CONTROL:
 390                         if (!cpu_has_dsp) {
 391                                 ret = -EIO;
 392                                 break;
 393                         }
 394                         child->thread.dsp.dspcontrol = data;
 395                         break;
 396                 default:
 397                         /* The rest are not allowed. */
 398                         ret = -EIO;
 399                         break;
 400                 }
 401                 break;
 402                 }
 403
 404         case PTRACE_GETREGS:
 405                 ret = ptrace_getregs (child, (__u64 __user *) data);
 406                 break;
 407
 408         case PTRACE_SETREGS:
 409                 ret = ptrace_setregs (child, (__u64 __user *) data);
 410                 break;
 411
 412         case PTRACE_GETFPREGS:
 413                 ret = ptrace_getfpregs (child, (__u32 __user *) data);
 414                 break;
 415
 416         case PTRACE_SETFPREGS:
 417                 ret = ptrace_setfpregs (child, (__u32 __user *) data);
 418                 break;
 419
 420         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 421         case PTRACE_CONT: { /* restart after signal. */
 422                 ret = -EIO;
 423                 if (!valid_signal(data))
 424                         break;
 425                 if (request == PTRACE_SYSCALL) {
 426                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 427                 }
 428                 else {
 429                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 430                 }
 431                 child->exit_code = data;
 432                 wake_up_process(child);
 433                 ret = 0;
 434                 break;
 435         }
 436
 437         /*
 438          * make the child exit.  Best I can do is send it a sigkill.
 439          * perhaps it should be put in the status that it wants to
 440          * exit.
 441          */
 442         case PTRACE_KILL:
 443                 ret = 0;
 444                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 445                         break;
 446                 child->exit_code = SIGKILL;
 447                 wake_up_process(child);
 448                 break;
 449
 450         case PTRACE_DETACH: /* detach a process that was attached. */
 451                 ret = ptrace_detach(child, data);
 452                 break;
 453
 454         case PTRACE_GET_THREAD_AREA:
 455                 ret = put_user(task_thread_info(child)->tp_value,
 456                                 (unsigned long __user *) data);
 457                 break;
 458
 459         default:
 460                 ret = ptrace_request(child, request, addr, data);
 461                 break;
 462         }
 463  out:
 464         return ret;
 465 }
 466
 467 static inline int audit_arch(void)
 468 {
 469         int arch = EM_MIPS;
 470 #ifdef CONFIG_64BIT
 471         arch |=  __AUDIT_ARCH_64BIT;
 472 #endif
 473 #if defined(__LITTLE_ENDIAN)
 474         arch |=  __AUDIT_ARCH_LE;
 475 #endif
 476         return arch;
 477 }
 478
 479 /*
 480  * Notification of system call entry/exit
 481  * - triggered by current->work.syscall_trace
 482  */
 483 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
 484 {
 485         if (unlikely(current->audit_context) && entryexit)
 486                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[2]),
 487                                    regs->regs[2]);
 488
 489         if (!(current->ptrace & PT_PTRACED))
 490                 goto out;
 491         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 492                 goto out;
 493
 494         /* The 0x80 provides a way for the tracing parent to distinguish
 495            between a syscall stop and SIGTRAP delivery */
 496         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
 497                                  0x80 : 0));
 498
 499         /*
 500          * this isn't the same as continuing with a signal, but it will do
 501          * for normal use.  strace only continues with a signal if the
 502          * stopping signal is not SIGTRAP.  -brl
 503          */
 504         if (current->exit_code) {
 505                 send_sig(current->exit_code, current, 1);
 506                 current->exit_code = 0;
 507         }
 508  out:
 509         if (unlikely(current->audit_context) && !entryexit)
 510                 audit_syscall_entry(audit_arch(), regs->regs[2],
 511                                     regs->regs[4], regs->regs[5],
 512                                     regs->regs[6], regs->regs[7]);
 513 }