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/pgtable.h>
  37 #include <asm/page.h>
  38 #include <asm/system.h>
  39 #include <asm/uaccess.h>
  40 #include <asm/bootinfo.h>
  41 #include <asm/reg.h>
  42
  43 /*
  44  * Called by kernel/ptrace.c when detaching..
  45  *
  46  * Make sure single step bits etc are not set.
  47  */
  48 void ptrace_disable(struct task_struct *child)
  49 {
  50         /* Nothing to do.. */
  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 = (struct pt_regs *) ((unsigned long) child->thread_info +
  67                THREAD_SIZE - 32 - sizeof(struct pt_regs));
  68
  69         for (i = 0; i < 32; i++)
  70                 __put_user (regs->regs[i], data + i);
  71         __put_user (regs->lo, data + EF_LO - EF_R0);
  72         __put_user (regs->hi, data + EF_HI - EF_R0);
  73         __put_user (regs->cp0_epc, data + EF_CP0_EPC - EF_R0);
  74         __put_user (regs->cp0_badvaddr, data + EF_CP0_BADVADDR - EF_R0);
  75         __put_user (regs->cp0_status, data + EF_CP0_STATUS - EF_R0);
  76         __put_user (regs->cp0_cause, data + EF_CP0_CAUSE - EF_R0);
  77
  78         return 0;
  79 }
  80
  81 /*
  82  * Write a general register set.  As for PTRACE_GETREGS, we always use
  83  * the 64-bit format.  On a 32-bit kernel only the lower order half
  84  * (according to endianness) will be used.
  85  */
  86 int ptrace_setregs (struct task_struct *child, __s64 __user *data)
  87 {
  88         struct pt_regs *regs;
  89         int i;
  90
  91         if (!access_ok(VERIFY_READ, data, 38 * 8))
  92                 return -EIO;
  93
  94         regs = (struct pt_regs *) ((unsigned long) child->thread_info +
  95                THREAD_SIZE - 32 - sizeof(struct pt_regs));
  96
  97         for (i = 0; i < 32; i++)
  98                 __get_user (regs->regs[i], data + i);
  99         __get_user (regs->lo, data + EF_LO - EF_R0);
 100         __get_user (regs->hi, data + EF_HI - EF_R0);
 101         __get_user (regs->cp0_epc, data + EF_CP0_EPC - EF_R0);
 102
 103         /* badvaddr, status, and cause may not be written.  */
 104
 105         return 0;
 106 }
 107
 108 int ptrace_getfpregs (struct task_struct *child, __u32 __user *data)
 109 {
 110         int i;
 111
 112         if (!access_ok(VERIFY_WRITE, data, 33 * 8))
 113                 return -EIO;
 114
 115         if (tsk_used_math(child)) {
 116                 fpureg_t *fregs = get_fpu_regs(child);
 117                 for (i = 0; i < 32; i++)
 118                         __put_user (fregs[i], i + (__u64 __user *) data);
 119         } else {
 120                 for (i = 0; i < 32; i++)
 121                         __put_user ((__u64) -1, i + (__u64 __user *) data);
 122         }
 123
 124         if (cpu_has_fpu) {
 125                 unsigned int flags, tmp;
 126
 127                 __put_user (child->thread.fpu.hard.fcr31, data + 64);
 128
 129                 flags = read_c0_status();
 130                 __enable_fpu();
 131                 __asm__ __volatile__("cfc1\t%0,$0" : "=r" (tmp));
 132                 write_c0_status(flags);
 133                 __put_user (tmp, data + 65);
 134         } else {
 135                 __put_user (child->thread.fpu.soft.fcr31, data + 64);
 136                 __put_user ((__u32) 0, data + 65);
 137         }
 138
 139         return 0;
 140 }
 141
 142 int ptrace_setfpregs (struct task_struct *child, __u32 __user *data)
 143 {
 144         fpureg_t *fregs;
 145         int i;
 146
 147         if (!access_ok(VERIFY_READ, data, 33 * 8))
 148                 return -EIO;
 149
 150         fregs = get_fpu_regs(child);
 151
 152         for (i = 0; i < 32; i++)
 153                 __get_user (fregs[i], i + (__u64 __user *) data);
 154
 155         if (cpu_has_fpu)
 156                 __get_user (child->thread.fpu.hard.fcr31, data + 64);
 157         else
 158                 __get_user (child->thread.fpu.soft.fcr31, data + 64);
 159
 160         /* FIR may not be written.  */
 161
 162         return 0;
 163 }
 164
 165 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 166 {
 167         struct task_struct *child;
 168         int ret;
 169
 170 #if 0
 171         printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n",
 172                (int) request, (int) pid, (unsigned long) addr,
 173                (unsigned long) data);
 174 #endif
 175         lock_kernel();
 176         ret = -EPERM;
 177         if (request == PTRACE_TRACEME) {
 178                 /* are we already being traced? */
 179                 if (current->ptrace & PT_PTRACED)
 180                         goto out;
 181                 if ((ret = security_ptrace(current->parent, current)))
 182                         goto out;
 183                 /* set the ptrace bit in the process flags. */
 184                 current->ptrace |= PT_PTRACED;
 185                 ret = 0;
 186                 goto out;
 187         }
 188         ret = -ESRCH;
 189         read_lock(&tasklist_lock);
 190         child = find_task_by_pid(pid);
 191         if (child)
 192                 get_task_struct(child);
 193         read_unlock(&tasklist_lock);
 194         if (!child)
 195                 goto out;
 196
 197         ret = -EPERM;
 198         if (pid == 1)           /* you may not mess with init */
 199                 goto out_tsk;
 200
 201         if (request == PTRACE_ATTACH) {
 202                 ret = ptrace_attach(child);
 203                 goto out_tsk;
 204         }
 205
 206         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 207         if (ret < 0)
 208                 goto out_tsk;
 209
 210         switch (request) {
 211         /* when I and D space are separate, these will need to be fixed. */
 212         case PTRACE_PEEKTEXT: /* read word at location addr. */
 213         case PTRACE_PEEKDATA: {
 214                 unsigned long tmp;
 215                 int copied;
 216
 217                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 218                 ret = -EIO;
 219                 if (copied != sizeof(tmp))
 220                         break;
 221                 ret = put_user(tmp,(unsigned long __user *) data);
 222                 break;
 223         }
 224
 225         /* Read the word at location addr in the USER area. */
 226         case PTRACE_PEEKUSR: {
 227                 struct pt_regs *regs;
 228                 unsigned long tmp = 0;
 229
 230                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 231                        THREAD_SIZE - 32 - sizeof(struct pt_regs));
 232                 ret = 0;  /* Default return value. */
 233
 234                 switch (addr) {
 235                 case 0 ... 31:
 236                         tmp = regs->regs[addr];
 237                         break;
 238                 case FPR_BASE ... FPR_BASE + 31:
 239                         if (tsk_used_math(child)) {
 240                                 fpureg_t *fregs = get_fpu_regs(child);
 241
 242 #ifdef CONFIG_32BIT
 243                                 /*
 244                                  * The odd registers are actually the high
 245                                  * order bits of the values stored in the even
 246                                  * registers - unless we're using r2k_switch.S.
 247                                  */
 248                                 if (addr & 1)
 249                                         tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
 250                                 else
 251                                         tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
 252 #endif
 253 #ifdef CONFIG_64BIT
 254                                 tmp = fregs[addr - FPR_BASE];
 255 #endif
 256                         } else {
 257                                 tmp = -1;       /* FP not yet used  */
 258                         }
 259                         break;
 260                 case PC:
 261                         tmp = regs->cp0_epc;
 262                         break;
 263                 case CAUSE:
 264                         tmp = regs->cp0_cause;
 265                         break;
 266                 case BADVADDR:
 267                         tmp = regs->cp0_badvaddr;
 268                         break;
 269                 case MMHI:
 270                         tmp = regs->hi;
 271                         break;
 272                 case MMLO:
 273                         tmp = regs->lo;
 274                         break;
 275                 case FPC_CSR:
 276                         if (cpu_has_fpu)
 277                                 tmp = child->thread.fpu.hard.fcr31;
 278                         else
 279                                 tmp = child->thread.fpu.soft.fcr31;
 280                         break;
 281                 case FPC_EIR: { /* implementation / version register */
 282                         unsigned int flags;
 283
 284                         if (!cpu_has_fpu)
 285                                 break;
 286
 287                         flags = read_c0_status();
 288                         __enable_fpu();
 289                         __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 290                         write_c0_status(flags);
 291                         break;
 292                 }
 293                 case DSP_BASE ... DSP_BASE + 5: {
 294                         dspreg_t *dregs;
 295
 296                         if (!cpu_has_dsp) {
 297                                 tmp = 0;
 298                                 ret = -EIO;
 299                                 goto out_tsk;
 300                         }
 301                         if (child->thread.dsp.used_dsp) {
 302                                 dregs = __get_dsp_regs(child);
 303                                 tmp = (unsigned long) (dregs[addr - DSP_BASE]);
 304                         } else {
 305                                 tmp = -1;       /* DSP registers yet used  */
 306                         }
 307                         break;
 308                 }
 309                 case DSP_CONTROL:
 310                         if (!cpu_has_dsp) {
 311                                 tmp = 0;
 312                                 ret = -EIO;
 313                                 goto out_tsk;
 314                         }
 315                         tmp = child->thread.dsp.dspcontrol;
 316                         break;
 317                 default:
 318                         tmp = 0;
 319                         ret = -EIO;
 320                         goto out_tsk;
 321                 }
 322                 ret = put_user(tmp, (unsigned long __user *) data);
 323                 break;
 324         }
 325
 326         /* when I and D space are separate, this will have to be fixed. */
 327         case PTRACE_POKETEXT: /* write the word at location addr. */
 328         case PTRACE_POKEDATA:
 329                 ret = 0;
 330                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 331                     == sizeof(data))
 332                         break;
 333                 ret = -EIO;
 334                 break;
 335
 336         case PTRACE_POKEUSR: {
 337                 struct pt_regs *regs;
 338                 ret = 0;
 339                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 340                        THREAD_SIZE - 32 - sizeof(struct pt_regs));
 341
 342                 switch (addr) {
 343                 case 0 ... 31:
 344                         regs->regs[addr] = data;
 345                         break;
 346                 case FPR_BASE ... FPR_BASE + 31: {
 347                         fpureg_t *fregs = get_fpu_regs(child);
 348
 349                         if (!tsk_used_math(child)) {
 350                                 /* FP not yet used  */
 351                                 memset(&child->thread.fpu.hard, ~0,
 352                                        sizeof(child->thread.fpu.hard));
 353                                 child->thread.fpu.hard.fcr31 = 0;
 354                         }
 355 #ifdef CONFIG_32BIT
 356                         /*
 357                          * The odd registers are actually the high order bits
 358                          * of the values stored in the even registers - unless
 359                          * we're using r2k_switch.S.
 360                          */
 361                         if (addr & 1) {
 362                                 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
 363                                 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
 364                         } else {
 365                                 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
 366                                 fregs[addr - FPR_BASE] |= data;
 367                         }
 368 #endif
 369 #ifdef CONFIG_64BIT
 370                         fregs[addr - FPR_BASE] = data;
 371 #endif
 372                         break;
 373                 }
 374                 case PC:
 375                         regs->cp0_epc = data;
 376                         break;
 377                 case MMHI:
 378                         regs->hi = data;
 379                         break;
 380                 case MMLO:
 381                         regs->lo = data;
 382                         break;
 383                 case FPC_CSR:
 384                         if (cpu_has_fpu)
 385                                 child->thread.fpu.hard.fcr31 = data;
 386                         else
 387                                 child->thread.fpu.soft.fcr31 = data;
 388                         break;
 389                 case DSP_BASE ... DSP_BASE + 5: {
 390                         dspreg_t *dregs;
 391
 392                         if (!cpu_has_dsp) {
 393                                 ret = -EIO;
 394                                 break;
 395                         }
 396
 397                         dregs = __get_dsp_regs(child);
 398                         dregs[addr - DSP_BASE] = data;
 399                         break;
 400                 }
 401                 case DSP_CONTROL:
 402                         if (!cpu_has_dsp) {
 403                                 ret = -EIO;
 404                                 break;
 405                         }
 406                         child->thread.dsp.dspcontrol = data;
 407                         break;
 408                 default:
 409                         /* The rest are not allowed. */
 410                         ret = -EIO;
 411                         break;
 412                 }
 413                 break;
 414                 }
 415
 416         case PTRACE_GETREGS:
 417                 ret = ptrace_getregs (child, (__u64 __user *) data);
 418                 break;
 419
 420         case PTRACE_SETREGS:
 421                 ret = ptrace_setregs (child, (__u64 __user *) data);
 422                 break;
 423
 424         case PTRACE_GETFPREGS:
 425                 ret = ptrace_getfpregs (child, (__u32 __user *) data);
 426                 break;
 427
 428         case PTRACE_SETFPREGS:
 429                 ret = ptrace_setfpregs (child, (__u32 __user *) data);
 430                 break;
 431
 432         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 433         case PTRACE_CONT: { /* restart after signal. */
 434                 ret = -EIO;
 435                 if (!valid_signal(data))
 436                         break;
 437                 if (request == PTRACE_SYSCALL) {
 438                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 439                 }
 440                 else {
 441                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 442                 }
 443                 child->exit_code = data;
 444                 wake_up_process(child);
 445                 ret = 0;
 446                 break;
 447         }
 448
 449         /*
 450          * make the child exit.  Best I can do is send it a sigkill.
 451          * perhaps it should be put in the status that it wants to
 452          * exit.
 453          */
 454         case PTRACE_KILL:
 455                 ret = 0;
 456                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 457                         break;
 458                 child->exit_code = SIGKILL;
 459                 wake_up_process(child);
 460                 break;
 461
 462         case PTRACE_DETACH: /* detach a process that was attached. */
 463                 ret = ptrace_detach(child, data);
 464                 break;
 465
 466         case PTRACE_GET_THREAD_AREA:
 467                 ret = put_user(child->thread_info->tp_value,
 468                                 (unsigned long __user *) data);
 469                 break;
 470
 471         default:
 472                 ret = ptrace_request(child, request, addr, data);
 473                 break;
 474         }
 475
 476 out_tsk:
 477         put_task_struct(child);
 478 out:
 479         unlock_kernel();
 480         return ret;
 481 }
 482
 483 static inline int audit_arch(void)
 484 {
 485         int arch = EM_MIPS;
 486 #ifdef CONFIG_64BIT
 487         arch |=  __AUDIT_ARCH_64BIT;
 488 #endif
 489 #if defined(__LITTLE_ENDIAN)
 490         arch |=  __AUDIT_ARCH_LE;
 491 #endif
 492         return arch;
 493 }
 494
 495 /*
 496  * Notification of system call entry/exit
 497  * - triggered by current->work.syscall_trace
 498  */
 499 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
 500 {
 501         if (unlikely(current->audit_context) && entryexit)
 502                 audit_syscall_exit(current, AUDITSC_RESULT(regs->regs[2]),
 503                                    regs->regs[2]);
 504
 505         if (!(current->ptrace & PT_PTRACED))
 506                 goto out;
 507         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 508                 goto out;
 509
 510         /* The 0x80 provides a way for the tracing parent to distinguish
 511            between a syscall stop and SIGTRAP delivery */
 512         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
 513                                  0x80 : 0));
 514
 515         /*
 516          * this isn't the same as continuing with a signal, but it will do
 517          * for normal use.  strace only continues with a signal if the
 518          * stopping signal is not SIGTRAP.  -brl
 519          */
 520         if (current->exit_code) {
 521                 send_sig(current->exit_code, current, 1);
 522                 current->exit_code = 0;
 523         }
 524  out:
 525         if (unlikely(current->audit_context) && !entryexit)
 526                 audit_syscall_entry(current, audit_arch(), regs->regs[2],
 527                                     regs->regs[4], regs->regs[5],
 528                                     regs->regs[6], regs->regs[7]);
 529 }