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/smp.h>
  24 #include <linux/user.h>
  25 #include <linux/security.h>
  26 #include <linux/audit.h>
  27 #include <linux/seccomp.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                 ret = generic_ptrace_peekdata(child, addr, data);
 179                 break;
 180
 181         /* Read the word at location addr in the USER area. */
 182         case PTRACE_PEEKUSR: {
 183                 struct pt_regs *regs;
 184                 unsigned long tmp = 0;
 185
 186                 regs = task_pt_regs(child);
 187                 ret = 0;  /* Default return value. */
 188
 189                 switch (addr) {
 190                 case 0 ... 31:
 191                         tmp = regs->regs[addr];
 192                         break;
 193                 case FPR_BASE ... FPR_BASE + 31:
 194                         if (tsk_used_math(child)) {
 195                                 fpureg_t *fregs = get_fpu_regs(child);
 196
 197 #ifdef CONFIG_32BIT
 198                                 /*
 199                                  * The odd registers are actually the high
 200                                  * order bits of the values stored in the even
 201                                  * registers - unless we're using r2k_switch.S.
 202                                  */
 203                                 if (addr & 1)
 204                                         tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
 205                                 else
 206                                         tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
 207 #endif
 208 #ifdef CONFIG_64BIT
 209                                 tmp = fregs[addr - FPR_BASE];
 210 #endif
 211                         } else {
 212                                 tmp = -1;       /* FP not yet used  */
 213                         }
 214                         break;
 215                 case PC:
 216                         tmp = regs->cp0_epc;
 217                         break;
 218                 case CAUSE:
 219                         tmp = regs->cp0_cause;
 220                         break;
 221                 case BADVADDR:
 222                         tmp = regs->cp0_badvaddr;
 223                         break;
 224                 case MMHI:
 225                         tmp = regs->hi;
 226                         break;
 227                 case MMLO:
 228                         tmp = regs->lo;
 229                         break;
 230 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 231                 case ACX:
 232                         tmp = regs->acx;
 233                         break;
 234 #endif
 235                 case FPC_CSR:
 236                         tmp = child->thread.fpu.fcr31;
 237                         break;
 238                 case FPC_EIR: { /* implementation / version register */
 239                         unsigned int flags;
 240 #ifdef CONFIG_MIPS_MT_SMTC
 241                         unsigned int irqflags;
 242                         unsigned int mtflags;
 243 #endif /* CONFIG_MIPS_MT_SMTC */
 244
 245                         preempt_disable();
 246                         if (!cpu_has_fpu) {
 247                                 preempt_enable();
 248                                 break;
 249                         }
 250
 251 #ifdef CONFIG_MIPS_MT_SMTC
 252                         /* Read-modify-write of Status must be atomic */
 253                         local_irq_save(irqflags);
 254                         mtflags = dmt();
 255 #endif /* CONFIG_MIPS_MT_SMTC */
 256                         if (cpu_has_mipsmt) {
 257                                 unsigned int vpflags = dvpe();
 258                                 flags = read_c0_status();
 259                                 __enable_fpu();
 260                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 261                                 write_c0_status(flags);
 262                                 evpe(vpflags);
 263                         } else {
 264                                 flags = read_c0_status();
 265                                 __enable_fpu();
 266                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 267                                 write_c0_status(flags);
 268                         }
 269 #ifdef CONFIG_MIPS_MT_SMTC
 270                         emt(mtflags);
 271                         local_irq_restore(irqflags);
 272 #endif /* CONFIG_MIPS_MT_SMTC */
 273                         preempt_enable();
 274                         break;
 275                 }
 276                 case DSP_BASE ... DSP_BASE + 5: {
 277                         dspreg_t *dregs;
 278
 279                         if (!cpu_has_dsp) {
 280                                 tmp = 0;
 281                                 ret = -EIO;
 282                                 goto out;
 283                         }
 284                         dregs = __get_dsp_regs(child);
 285                         tmp = (unsigned long) (dregs[addr - DSP_BASE]);
 286                         break;
 287                 }
 288                 case DSP_CONTROL:
 289                         if (!cpu_has_dsp) {
 290                                 tmp = 0;
 291                                 ret = -EIO;
 292                                 goto out;
 293                         }
 294                         tmp = child->thread.dsp.dspcontrol;
 295                         break;
 296                 default:
 297                         tmp = 0;
 298                         ret = -EIO;
 299                         goto out;
 300                 }
 301                 ret = put_user(tmp, (unsigned long __user *) data);
 302                 break;
 303         }
 304
 305         /* when I and D space are separate, this will have to be fixed. */
 306         case PTRACE_POKETEXT: /* write the word at location addr. */
 307         case PTRACE_POKEDATA:
 308                 ret = generic_ptrace_pokedata(child, addr, data);
 309                 break;
 310
 311         case PTRACE_POKEUSR: {
 312                 struct pt_regs *regs;
 313                 ret = 0;
 314                 regs = task_pt_regs(child);
 315
 316                 switch (addr) {
 317                 case 0 ... 31:
 318                         regs->regs[addr] = data;
 319                         break;
 320                 case FPR_BASE ... FPR_BASE + 31: {
 321                         fpureg_t *fregs = get_fpu_regs(child);
 322
 323                         if (!tsk_used_math(child)) {
 324                                 /* FP not yet used  */
 325                                 memset(&child->thread.fpu, ~0,
 326                                        sizeof(child->thread.fpu));
 327                                 child->thread.fpu.fcr31 = 0;
 328                         }
 329 #ifdef CONFIG_32BIT
 330                         /*
 331                          * The odd registers are actually the high order bits
 332                          * of the values stored in the even registers - unless
 333                          * we're using r2k_switch.S.
 334                          */
 335                         if (addr & 1) {
 336                                 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
 337                                 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
 338                         } else {
 339                                 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
 340                                 fregs[addr - FPR_BASE] |= data;
 341                         }
 342 #endif
 343 #ifdef CONFIG_64BIT
 344                         fregs[addr - FPR_BASE] = data;
 345 #endif
 346                         break;
 347                 }
 348                 case PC:
 349                         regs->cp0_epc = data;
 350                         break;
 351                 case MMHI:
 352                         regs->hi = data;
 353                         break;
 354                 case MMLO:
 355                         regs->lo = data;
 356                         break;
 357 #ifdef CONFIG_CPU_HAS_SMARTMIPS
 358                 case ACX:
 359                         regs->acx = data;
 360                         break;
 361 #endif
 362                 case FPC_CSR:
 363                         child->thread.fpu.fcr31 = data;
 364                         break;
 365                 case DSP_BASE ... DSP_BASE + 5: {
 366                         dspreg_t *dregs;
 367
 368                         if (!cpu_has_dsp) {
 369                                 ret = -EIO;
 370                                 break;
 371                         }
 372
 373                         dregs = __get_dsp_regs(child);
 374                         dregs[addr - DSP_BASE] = data;
 375                         break;
 376                 }
 377                 case DSP_CONTROL:
 378                         if (!cpu_has_dsp) {
 379                                 ret = -EIO;
 380                                 break;
 381                         }
 382                         child->thread.dsp.dspcontrol = data;
 383                         break;
 384                 default:
 385                         /* The rest are not allowed. */
 386                         ret = -EIO;
 387                         break;
 388                 }
 389                 break;
 390                 }
 391
 392         case PTRACE_GETREGS:
 393                 ret = ptrace_getregs(child, (__u64 __user *) data);
 394                 break;
 395
 396         case PTRACE_SETREGS:
 397                 ret = ptrace_setregs(child, (__u64 __user *) data);
 398                 break;
 399
 400         case PTRACE_GETFPREGS:
 401                 ret = ptrace_getfpregs(child, (__u32 __user *) data);
 402                 break;
 403
 404         case PTRACE_SETFPREGS:
 405                 ret = ptrace_setfpregs(child, (__u32 __user *) data);
 406                 break;
 407
 408         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 409         case PTRACE_CONT: { /* restart after signal. */
 410                 ret = -EIO;
 411                 if (!valid_signal(data))
 412                         break;
 413                 if (request == PTRACE_SYSCALL) {
 414                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 415                 }
 416                 else {
 417                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 418                 }
 419                 child->exit_code = data;
 420                 wake_up_process(child);
 421                 ret = 0;
 422                 break;
 423         }
 424
 425         /*
 426          * make the child exit.  Best I can do is send it a sigkill.
 427          * perhaps it should be put in the status that it wants to
 428          * exit.
 429          */
 430         case PTRACE_KILL:
 431                 ret = 0;
 432                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 433                         break;
 434                 child->exit_code = SIGKILL;
 435                 wake_up_process(child);
 436                 break;
 437
 438         case PTRACE_DETACH: /* detach a process that was attached. */
 439                 ret = ptrace_detach(child, data);
 440                 break;
 441
 442         case PTRACE_GET_THREAD_AREA:
 443                 ret = put_user(task_thread_info(child)->tp_value,
 444                                 (unsigned long __user *) data);
 445                 break;
 446
 447         default:
 448                 ret = ptrace_request(child, request, addr, data);
 449                 break;
 450         }
 451  out:
 452         return ret;
 453 }
 454
 455 static inline int audit_arch(void)
 456 {
 457         int arch = EM_MIPS;
 458 #ifdef CONFIG_64BIT
 459         arch |=  __AUDIT_ARCH_64BIT;
 460 #endif
 461 #if defined(__LITTLE_ENDIAN)
 462         arch |=  __AUDIT_ARCH_LE;
 463 #endif
 464         return arch;
 465 }
 466
 467 /*
 468  * Notification of system call entry/exit
 469  * - triggered by current->work.syscall_trace
 470  */
 471 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
 472 {
 473         /* do the secure computing check first */
 474         if (!entryexit)
 475                 secure_computing(regs->regs[0]);
 476
 477         if (unlikely(current->audit_context) && entryexit)
 478                 audit_syscall_exit(AUDITSC_RESULT(regs->regs[2]),
 479                                    regs->regs[2]);
 480
 481         if (!(current->ptrace & PT_PTRACED))
 482                 goto out;
 483
 484         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 485                 goto out;
 486
 487         /* The 0x80 provides a way for the tracing parent to distinguish
 488            between a syscall stop and SIGTRAP delivery */
 489         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
 490                                  0x80 : 0));
 491
 492         /*
 493          * this isn't the same as continuing with a signal, but it will do
 494          * for normal use.  strace only continues with a signal if the
 495          * stopping signal is not SIGTRAP.  -brl
 496          */
 497         if (current->exit_code) {
 498                 send_sig(current->exit_code, current, 1);
 499                 current->exit_code = 0;
 500         }
 501
 502 out:
 503         if (unlikely(current->audit_context) && !entryexit)
 504                 audit_syscall_entry(audit_arch(), regs->regs[0],
 505                                     regs->regs[4], regs->regs[5],
 506                                     regs->regs[6], regs->regs[7]);
 507 }