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/config.h>
  18 #include <linux/compiler.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/audit.h>
  25 #include <linux/smp.h>
  26 #include <linux/smp_lock.h>
  27 #include <linux/user.h>
  28 #include <linux/security.h>
  29 #include <linux/signal.h>
  30
  31 #include <asm/byteorder.h>
  32 #include <asm/cpu.h>
  33 #include <asm/dsp.h>
  34 #include <asm/fpu.h>
  35 #include <asm/mipsregs.h>
  36 #include <asm/mipsmtregs.h>
  37 #include <asm/pgtable.h>
  38 #include <asm/page.h>
  39 #include <asm/system.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/bootinfo.h>
  42 #include <asm/reg.h>
  43
  44 /*
  45  * Called by kernel/ptrace.c when detaching..
  46  *
  47  * Make sure single step bits etc are not set.
  48  */
  49 void ptrace_disable(struct task_struct *child)
  50 {
  51         /* Nothing to do.. */
  52 }
  53
  54 /*
  55  * Read a general register set.  We always use the 64-bit format, even
  56  * for 32-bit kernels and for 32-bit processes on a 64-bit kernel.
  57  * Registers are sign extended to fill the available space.
  58  */
  59 int ptrace_getregs (struct task_struct *child, __s64 __user *data)
  60 {
  61         struct pt_regs *regs;
  62         int i;
  63
  64         if (!access_ok(VERIFY_WRITE, data, 38 * 8))
  65                 return -EIO;
  66
  67         regs = (struct pt_regs *) ((unsigned long) child->thread_info +
  68                THREAD_SIZE - 32 - sizeof(struct pt_regs));
  69
  70         for (i = 0; i < 32; i++)
  71                 __put_user (regs->regs[i], data + i);
  72         __put_user (regs->lo, data + EF_LO - EF_R0);
  73         __put_user (regs->hi, data + EF_HI - EF_R0);
  74         __put_user (regs->cp0_epc, data + EF_CP0_EPC - EF_R0);
  75         __put_user (regs->cp0_badvaddr, data + EF_CP0_BADVADDR - EF_R0);
  76         __put_user (regs->cp0_status, data + EF_CP0_STATUS - EF_R0);
  77         __put_user (regs->cp0_cause, data + EF_CP0_CAUSE - EF_R0);
  78
  79         return 0;
  80 }
  81
  82 /*
  83  * Write a general register set.  As for PTRACE_GETREGS, we always use
  84  * the 64-bit format.  On a 32-bit kernel only the lower order half
  85  * (according to endianness) will be used.
  86  */
  87 int ptrace_setregs (struct task_struct *child, __s64 __user *data)
  88 {
  89         struct pt_regs *regs;
  90         int i;
  91
  92         if (!access_ok(VERIFY_READ, data, 38 * 8))
  93                 return -EIO;
  94
  95         regs = (struct pt_regs *) ((unsigned long) child->thread_info +
  96                THREAD_SIZE - 32 - sizeof(struct pt_regs));
  97
  98         for (i = 0; i < 32; i++)
  99                 __get_user (regs->regs[i], data + i);
 100         __get_user (regs->lo, data + EF_LO - EF_R0);
 101         __get_user (regs->hi, data + EF_HI - EF_R0);
 102         __get_user (regs->cp0_epc, data + EF_CP0_EPC - EF_R0);
 103
 104         /* badvaddr, status, and cause may not be written.  */
 105
 106         return 0;
 107 }
 108
 109 int ptrace_getfpregs (struct task_struct *child, __u32 __user *data)
 110 {
 111         int i;
 112
 113         if (!access_ok(VERIFY_WRITE, data, 33 * 8))
 114                 return -EIO;
 115
 116         if (tsk_used_math(child)) {
 117                 fpureg_t *fregs = get_fpu_regs(child);
 118                 for (i = 0; i < 32; i++)
 119                         __put_user (fregs[i], i + (__u64 __user *) data);
 120         } else {
 121                 for (i = 0; i < 32; i++)
 122                         __put_user ((__u64) -1, i + (__u64 __user *) data);
 123         }
 124
 125         if (cpu_has_fpu) {
 126                 unsigned int flags, tmp;
 127
 128                 __put_user (child->thread.fpu.hard.fcr31, data + 64);
 129
 130                 preempt_disable();
 131                 if (cpu_has_mipsmt) {
 132                         unsigned int vpflags = dvpe();
 133                         flags = read_c0_status();
 134                         __enable_fpu();
 135                         __asm__ __volatile__("cfc1\t%0,$0" : "=r" (tmp));
 136                         write_c0_status(flags);
 137                         evpe(vpflags);
 138                 } else {
 139                         flags = read_c0_status();
 140                         __enable_fpu();
 141                         __asm__ __volatile__("cfc1\t%0,$0" : "=r" (tmp));
 142                         write_c0_status(flags);
 143                 }
 144                 preempt_enable();
 145                 __put_user (tmp, data + 65);
 146         } else {
 147                 __put_user (child->thread.fpu.soft.fcr31, data + 64);
 148                 __put_user ((__u32) 0, data + 65);
 149         }
 150
 151         return 0;
 152 }
 153
 154 int ptrace_setfpregs (struct task_struct *child, __u32 __user *data)
 155 {
 156         fpureg_t *fregs;
 157         int i;
 158
 159         if (!access_ok(VERIFY_READ, data, 33 * 8))
 160                 return -EIO;
 161
 162         fregs = get_fpu_regs(child);
 163
 164         for (i = 0; i < 32; i++)
 165                 __get_user (fregs[i], i + (__u64 __user *) data);
 166
 167         if (cpu_has_fpu)
 168                 __get_user (child->thread.fpu.hard.fcr31, data + 64);
 169         else
 170                 __get_user (child->thread.fpu.soft.fcr31, data + 64);
 171
 172         /* FIR may not be written.  */
 173
 174         return 0;
 175 }
 176
 177 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 178 {
 179         int ret;
 180
 181         switch (request) {
 182         /* when I and D space are separate, these will need to be fixed. */
 183         case PTRACE_PEEKTEXT: /* read word at location addr. */
 184         case PTRACE_PEEKDATA: {
 185                 unsigned long tmp;
 186                 int copied;
 187
 188                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 189                 ret = -EIO;
 190                 if (copied != sizeof(tmp))
 191                         break;
 192                 ret = put_user(tmp,(unsigned long __user *) data);
 193                 break;
 194         }
 195
 196         /* Read the word at location addr in the USER area. */
 197         case PTRACE_PEEKUSR: {
 198                 struct pt_regs *regs;
 199                 unsigned long tmp = 0;
 200
 201                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 202                        THREAD_SIZE - 32 - sizeof(struct pt_regs));
 203                 ret = 0;  /* Default return value. */
 204
 205                 switch (addr) {
 206                 case 0 ... 31:
 207                         tmp = regs->regs[addr];
 208                         break;
 209                 case FPR_BASE ... FPR_BASE + 31:
 210                         if (tsk_used_math(child)) {
 211                                 fpureg_t *fregs = get_fpu_regs(child);
 212
 213 #ifdef CONFIG_32BIT
 214                                 /*
 215                                  * The odd registers are actually the high
 216                                  * order bits of the values stored in the even
 217                                  * registers - unless we're using r2k_switch.S.
 218                                  */
 219                                 if (addr & 1)
 220                                         tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
 221                                 else
 222                                         tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
 223 #endif
 224 #ifdef CONFIG_64BIT
 225                                 tmp = fregs[addr - FPR_BASE];
 226 #endif
 227                         } else {
 228                                 tmp = -1;       /* FP not yet used  */
 229                         }
 230                         break;
 231                 case PC:
 232                         tmp = regs->cp0_epc;
 233                         break;
 234                 case CAUSE:
 235                         tmp = regs->cp0_cause;
 236                         break;
 237                 case BADVADDR:
 238                         tmp = regs->cp0_badvaddr;
 239                         break;
 240                 case MMHI:
 241                         tmp = regs->hi;
 242                         break;
 243                 case MMLO:
 244                         tmp = regs->lo;
 245                         break;
 246                 case FPC_CSR:
 247                         if (cpu_has_fpu)
 248                                 tmp = child->thread.fpu.hard.fcr31;
 249                         else
 250                                 tmp = child->thread.fpu.soft.fcr31;
 251                         break;
 252                 case FPC_EIR: { /* implementation / version register */
 253                         unsigned int flags;
 254
 255                         if (!cpu_has_fpu)
 256                                 break;
 257
 258                         preempt_disable();
 259                         if (cpu_has_mipsmt) {
 260                                 unsigned int vpflags = dvpe();
 261                                 flags = read_c0_status();
 262                                 __enable_fpu();
 263                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 264                                 write_c0_status(flags);
 265                                 evpe(vpflags);
 266                         } else {
 267                                 flags = read_c0_status();
 268                                 __enable_fpu();
 269                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 270                                 write_c0_status(flags);
 271                         }
 272                         preempt_enable();
 273                         break;
 274                 }
 275                 case DSP_BASE ... DSP_BASE + 5: {
 276                         dspreg_t *dregs;
 277
 278                         if (!cpu_has_dsp) {
 279                                 tmp = 0;
 280                                 ret = -EIO;
 281                                 goto out;
 282                         }
 283                         if (child->thread.dsp.used_dsp) {
 284                                 dregs = __get_dsp_regs(child);
 285                                 tmp = (unsigned long) (dregs[addr - DSP_BASE]);
 286                         } else {
 287                                 tmp = -1;       /* DSP registers yet used  */
 288                         }
 289                         break;
 290                 }
 291                 case DSP_CONTROL:
 292                         if (!cpu_has_dsp) {
 293                                 tmp = 0;
 294                                 ret = -EIO;
 295                                 goto out;
 296                         }
 297                         tmp = child->thread.dsp.dspcontrol;
 298                         break;
 299                 default:
 300                         tmp = 0;
 301                         ret = -EIO;
 302                         goto out;
 303                 }
 304                 ret = put_user(tmp, (unsigned long __user *) data);
 305                 break;
 306         }
 307
 308         /* when I and D space are separate, this will have to be fixed. */
 309         case PTRACE_POKETEXT: /* write the word at location addr. */
 310         case PTRACE_POKEDATA:
 311                 ret = 0;
 312                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 313                     == sizeof(data))
 314                         break;
 315                 ret = -EIO;
 316                 break;
 317
 318         case PTRACE_POKEUSR: {
 319                 struct pt_regs *regs;
 320                 ret = 0;
 321                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 322                        THREAD_SIZE - 32 - sizeof(struct pt_regs));
 323
 324                 switch (addr) {
 325                 case 0 ... 31:
 326                         regs->regs[addr] = data;
 327                         break;
 328                 case FPR_BASE ... FPR_BASE + 31: {
 329                         fpureg_t *fregs = get_fpu_regs(child);
 330
 331                         if (!tsk_used_math(child)) {
 332                                 /* FP not yet used  */
 333                                 memset(&child->thread.fpu.hard, ~0,
 334                                        sizeof(child->thread.fpu.hard));
 335                                 child->thread.fpu.hard.fcr31 = 0;
 336                         }
 337 #ifdef CONFIG_32BIT
 338                         /*
 339                          * The odd registers are actually the high order bits
 340                          * of the values stored in the even registers - unless
 341                          * we're using r2k_switch.S.
 342                          */
 343                         if (addr & 1) {
 344                                 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
 345                                 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
 346                         } else {
 347                                 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
 348                                 fregs[addr - FPR_BASE] |= data;
 349                         }
 350 #endif
 351 #ifdef CONFIG_64BIT
 352                         fregs[addr - FPR_BASE] = data;
 353 #endif
 354                         break;
 355                 }
 356                 case PC:
 357                         regs->cp0_epc = data;
 358                         break;
 359                 case MMHI:
 360                         regs->hi = data;
 361                         break;
 362                 case MMLO:
 363                         regs->lo = data;
 364                         break;
 365                 case FPC_CSR:
 366                         if (cpu_has_fpu)
 367                                 child->thread.fpu.hard.fcr31 = data;
 368                         else
 369                                 child->thread.fpu.soft.fcr31 = data;
 370                         break;
 371                 case DSP_BASE ... DSP_BASE + 5: {
 372                         dspreg_t *dregs;
 373
 374                         if (!cpu_has_dsp) {
 375                                 ret = -EIO;
 376                                 break;
 377                         }
 378
 379                         dregs = __get_dsp_regs(child);
 380                         dregs[addr - DSP_BASE] = data;
 381                         break;
 382                 }
 383                 case DSP_CONTROL:
 384                         if (!cpu_has_dsp) {
 385                                 ret = -EIO;
 386                                 break;
 387                         }
 388                         child->thread.dsp.dspcontrol = data;
 389                         break;
 390                 default:
 391                         /* The rest are not allowed. */
 392                         ret = -EIO;
 393                         break;
 394                 }
 395                 break;
 396                 }
 397
 398         case PTRACE_GETREGS:
 399                 ret = ptrace_getregs (child, (__u64 __user *) data);
 400                 break;
 401
 402         case PTRACE_SETREGS:
 403                 ret = ptrace_setregs (child, (__u64 __user *) data);
 404                 break;
 405
 406         case PTRACE_GETFPREGS:
 407                 ret = ptrace_getfpregs (child, (__u32 __user *) data);
 408                 break;
 409
 410         case PTRACE_SETFPREGS:
 411                 ret = ptrace_setfpregs (child, (__u32 __user *) data);
 412                 break;
 413
 414         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 415         case PTRACE_CONT: { /* restart after signal. */
 416                 ret = -EIO;
 417                 if (!valid_signal(data))
 418                         break;
 419                 if (request == PTRACE_SYSCALL) {
 420                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 421                 }
 422                 else {
 423                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 424                 }
 425                 child->exit_code = data;
 426                 wake_up_process(child);
 427                 ret = 0;
 428                 break;
 429         }
 430
 431         /*
 432          * make the child exit.  Best I can do is send it a sigkill.
 433          * perhaps it should be put in the status that it wants to
 434          * exit.
 435          */
 436         case PTRACE_KILL:
 437                 ret = 0;
 438                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 439                         break;
 440                 child->exit_code = SIGKILL;
 441                 wake_up_process(child);
 442                 break;
 443
 444         case PTRACE_DETACH: /* detach a process that was attached. */
 445                 ret = ptrace_detach(child, data);
 446                 break;
 447
 448         case PTRACE_GET_THREAD_AREA:
 449                 ret = put_user(child->thread_info->tp_value,
 450                                 (unsigned long __user *) data);
 451                 break;
 452
 453         default:
 454                 ret = ptrace_request(child, request, addr, data);
 455                 break;
 456         }
 457  out:
 458         return ret;
 459 }
 460
 461 static inline int audit_arch(void)
 462 {
 463         int arch = EM_MIPS;
 464 #ifdef CONFIG_64BIT
 465         arch |=  __AUDIT_ARCH_64BIT;
 466 #endif
 467 #if defined(__LITTLE_ENDIAN)
 468         arch |=  __AUDIT_ARCH_LE;
 469 #endif
 470         return arch;
 471 }
 472
 473 /*
 474  * Notification of system call entry/exit
 475  * - triggered by current->work.syscall_trace
 476  */
 477 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
 478 {
 479         if (unlikely(current->audit_context) && entryexit)
 480                 audit_syscall_exit(current, AUDITSC_RESULT(regs->regs[2]),
 481                                    regs->regs[2]);
 482
 483         if (!(current->ptrace & PT_PTRACED))
 484                 goto out;
 485         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 486                 goto out;
 487
 488         /* The 0x80 provides a way for the tracing parent to distinguish
 489            between a syscall stop and SIGTRAP delivery */
 490         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
 491                                  0x80 : 0));
 492
 493         /*
 494          * this isn't the same as continuing with a signal, but it will do
 495          * for normal use.  strace only continues with a signal if the
 496          * stopping signal is not SIGTRAP.  -brl
 497          */
 498         if (current->exit_code) {
 499                 send_sig(current->exit_code, current, 1);
 500                 current->exit_code = 0;
 501         }
 502  out:
 503         if (unlikely(current->audit_context) && !entryexit)
 504                 audit_syscall_entry(current, audit_arch(), regs->regs[2],
 505                                     regs->regs[4], regs->regs[5],
 506                                     regs->regs[6], regs->regs[7]);
 507 }