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 asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
 178 {
 179         struct task_struct *child;
 180         int ret;
 181
 182 #if 0
 183         printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n",
 184                (int) request, (int) pid, (unsigned long) addr,
 185                (unsigned long) data);
 186 #endif
 187         lock_kernel();
 188         ret = -EPERM;
 189         if (request == PTRACE_TRACEME) {
 190                 /* are we already being traced? */
 191                 if (current->ptrace & PT_PTRACED)
 192                         goto out;
 193                 if ((ret = security_ptrace(current->parent, current)))
 194                         goto out;
 195                 /* set the ptrace bit in the process flags. */
 196                 current->ptrace |= PT_PTRACED;
 197                 ret = 0;
 198                 goto out;
 199         }
 200         ret = -ESRCH;
 201         read_lock(&tasklist_lock);
 202         child = find_task_by_pid(pid);
 203         if (child)
 204                 get_task_struct(child);
 205         read_unlock(&tasklist_lock);
 206         if (!child)
 207                 goto out;
 208
 209         ret = -EPERM;
 210         if (pid == 1)           /* you may not mess with init */
 211                 goto out_tsk;
 212
 213         if (request == PTRACE_ATTACH) {
 214                 ret = ptrace_attach(child);
 215                 goto out_tsk;
 216         }
 217
 218         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 219         if (ret < 0)
 220                 goto out_tsk;
 221
 222         switch (request) {
 223         /* when I and D space are separate, these will need to be fixed. */
 224         case PTRACE_PEEKTEXT: /* read word at location addr. */
 225         case PTRACE_PEEKDATA: {
 226                 unsigned long tmp;
 227                 int copied;
 228
 229                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 230                 ret = -EIO;
 231                 if (copied != sizeof(tmp))
 232                         break;
 233                 ret = put_user(tmp,(unsigned long __user *) data);
 234                 break;
 235         }
 236
 237         /* Read the word at location addr in the USER area. */
 238         case PTRACE_PEEKUSR: {
 239                 struct pt_regs *regs;
 240                 unsigned long tmp = 0;
 241
 242                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 243                        THREAD_SIZE - 32 - sizeof(struct pt_regs));
 244                 ret = 0;  /* Default return value. */
 245
 246                 switch (addr) {
 247                 case 0 ... 31:
 248                         tmp = regs->regs[addr];
 249                         break;
 250                 case FPR_BASE ... FPR_BASE + 31:
 251                         if (tsk_used_math(child)) {
 252                                 fpureg_t *fregs = get_fpu_regs(child);
 253
 254 #ifdef CONFIG_32BIT
 255                                 /*
 256                                  * The odd registers are actually the high
 257                                  * order bits of the values stored in the even
 258                                  * registers - unless we're using r2k_switch.S.
 259                                  */
 260                                 if (addr & 1)
 261                                         tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
 262                                 else
 263                                         tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
 264 #endif
 265 #ifdef CONFIG_64BIT
 266                                 tmp = fregs[addr - FPR_BASE];
 267 #endif
 268                         } else {
 269                                 tmp = -1;       /* FP not yet used  */
 270                         }
 271                         break;
 272                 case PC:
 273                         tmp = regs->cp0_epc;
 274                         break;
 275                 case CAUSE:
 276                         tmp = regs->cp0_cause;
 277                         break;
 278                 case BADVADDR:
 279                         tmp = regs->cp0_badvaddr;
 280                         break;
 281                 case MMHI:
 282                         tmp = regs->hi;
 283                         break;
 284                 case MMLO:
 285                         tmp = regs->lo;
 286                         break;
 287                 case FPC_CSR:
 288                         if (cpu_has_fpu)
 289                                 tmp = child->thread.fpu.hard.fcr31;
 290                         else
 291                                 tmp = child->thread.fpu.soft.fcr31;
 292                         break;
 293                 case FPC_EIR: { /* implementation / version register */
 294                         unsigned int flags;
 295
 296                         if (!cpu_has_fpu)
 297                                 break;
 298
 299                         preempt_disable();
 300                         if (cpu_has_mipsmt) {
 301                                 unsigned int vpflags = dvpe();
 302                                 flags = read_c0_status();
 303                                 __enable_fpu();
 304                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 305                                 write_c0_status(flags);
 306                                 evpe(vpflags);
 307                         } else {
 308                                 flags = read_c0_status();
 309                                 __enable_fpu();
 310                                 __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 311                                 write_c0_status(flags);
 312                         }
 313                         preempt_enable();
 314                         break;
 315                 }
 316                 case DSP_BASE ... DSP_BASE + 5: {
 317                         dspreg_t *dregs;
 318
 319                         if (!cpu_has_dsp) {
 320                                 tmp = 0;
 321                                 ret = -EIO;
 322                                 goto out_tsk;
 323                         }
 324                         if (child->thread.dsp.used_dsp) {
 325                                 dregs = __get_dsp_regs(child);
 326                                 tmp = (unsigned long) (dregs[addr - DSP_BASE]);
 327                         } else {
 328                                 tmp = -1;       /* DSP registers yet used  */
 329                         }
 330                         break;
 331                 }
 332                 case DSP_CONTROL:
 333                         if (!cpu_has_dsp) {
 334                                 tmp = 0;
 335                                 ret = -EIO;
 336                                 goto out_tsk;
 337                         }
 338                         tmp = child->thread.dsp.dspcontrol;
 339                         break;
 340                 default:
 341                         tmp = 0;
 342                         ret = -EIO;
 343                         goto out_tsk;
 344                 }
 345                 ret = put_user(tmp, (unsigned long __user *) data);
 346                 break;
 347         }
 348
 349         /* when I and D space are separate, this will have to be fixed. */
 350         case PTRACE_POKETEXT: /* write the word at location addr. */
 351         case PTRACE_POKEDATA:
 352                 ret = 0;
 353                 if (access_process_vm(child, addr, &data, sizeof(data), 1)
 354                     == sizeof(data))
 355                         break;
 356                 ret = -EIO;
 357                 break;
 358
 359         case PTRACE_POKEUSR: {
 360                 struct pt_regs *regs;
 361                 ret = 0;
 362                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 363                        THREAD_SIZE - 32 - sizeof(struct pt_regs));
 364
 365                 switch (addr) {
 366                 case 0 ... 31:
 367                         regs->regs[addr] = data;
 368                         break;
 369                 case FPR_BASE ... FPR_BASE + 31: {
 370                         fpureg_t *fregs = get_fpu_regs(child);
 371
 372                         if (!tsk_used_math(child)) {
 373                                 /* FP not yet used  */
 374                                 memset(&child->thread.fpu.hard, ~0,
 375                                        sizeof(child->thread.fpu.hard));
 376                                 child->thread.fpu.hard.fcr31 = 0;
 377                         }
 378 #ifdef CONFIG_32BIT
 379                         /*
 380                          * The odd registers are actually the high order bits
 381                          * of the values stored in the even registers - unless
 382                          * we're using r2k_switch.S.
 383                          */
 384                         if (addr & 1) {
 385                                 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
 386                                 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
 387                         } else {
 388                                 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
 389                                 fregs[addr - FPR_BASE] |= data;
 390                         }
 391 #endif
 392 #ifdef CONFIG_64BIT
 393                         fregs[addr - FPR_BASE] = data;
 394 #endif
 395                         break;
 396                 }
 397                 case PC:
 398                         regs->cp0_epc = data;
 399                         break;
 400                 case MMHI:
 401                         regs->hi = data;
 402                         break;
 403                 case MMLO:
 404                         regs->lo = data;
 405                         break;
 406                 case FPC_CSR:
 407                         if (cpu_has_fpu)
 408                                 child->thread.fpu.hard.fcr31 = data;
 409                         else
 410                                 child->thread.fpu.soft.fcr31 = data;
 411                         break;
 412                 case DSP_BASE ... DSP_BASE + 5: {
 413                         dspreg_t *dregs;
 414
 415                         if (!cpu_has_dsp) {
 416                                 ret = -EIO;
 417                                 break;
 418                         }
 419
 420                         dregs = __get_dsp_regs(child);
 421                         dregs[addr - DSP_BASE] = data;
 422                         break;
 423                 }
 424                 case DSP_CONTROL:
 425                         if (!cpu_has_dsp) {
 426                                 ret = -EIO;
 427                                 break;
 428                         }
 429                         child->thread.dsp.dspcontrol = data;
 430                         break;
 431                 default:
 432                         /* The rest are not allowed. */
 433                         ret = -EIO;
 434                         break;
 435                 }
 436                 break;
 437                 }
 438
 439         case PTRACE_GETREGS:
 440                 ret = ptrace_getregs (child, (__u64 __user *) data);
 441                 break;
 442
 443         case PTRACE_SETREGS:
 444                 ret = ptrace_setregs (child, (__u64 __user *) data);
 445                 break;
 446
 447         case PTRACE_GETFPREGS:
 448                 ret = ptrace_getfpregs (child, (__u32 __user *) data);
 449                 break;
 450
 451         case PTRACE_SETFPREGS:
 452                 ret = ptrace_setfpregs (child, (__u32 __user *) data);
 453                 break;
 454
 455         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 456         case PTRACE_CONT: { /* restart after signal. */
 457                 ret = -EIO;
 458                 if (!valid_signal(data))
 459                         break;
 460                 if (request == PTRACE_SYSCALL) {
 461                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 462                 }
 463                 else {
 464                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 465                 }
 466                 child->exit_code = data;
 467                 wake_up_process(child);
 468                 ret = 0;
 469                 break;
 470         }
 471
 472         /*
 473          * make the child exit.  Best I can do is send it a sigkill.
 474          * perhaps it should be put in the status that it wants to
 475          * exit.
 476          */
 477         case PTRACE_KILL:
 478                 ret = 0;
 479                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 480                         break;
 481                 child->exit_code = SIGKILL;
 482                 wake_up_process(child);
 483                 break;
 484
 485         case PTRACE_DETACH: /* detach a process that was attached. */
 486                 ret = ptrace_detach(child, data);
 487                 break;
 488
 489         case PTRACE_GET_THREAD_AREA:
 490                 ret = put_user(child->thread_info->tp_value,
 491                                 (unsigned long __user *) data);
 492                 break;
 493
 494         default:
 495                 ret = ptrace_request(child, request, addr, data);
 496                 break;
 497         }
 498
 499 out_tsk:
 500         put_task_struct(child);
 501 out:
 502         unlock_kernel();
 503         return ret;
 504 }
 505
 506 static inline int audit_arch(void)
 507 {
 508         int arch = EM_MIPS;
 509 #ifdef CONFIG_64BIT
 510         arch |=  __AUDIT_ARCH_64BIT;
 511 #endif
 512 #if defined(__LITTLE_ENDIAN)
 513         arch |=  __AUDIT_ARCH_LE;
 514 #endif
 515         return arch;
 516 }
 517
 518 /*
 519  * Notification of system call entry/exit
 520  * - triggered by current->work.syscall_trace
 521  */
 522 asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
 523 {
 524         if (unlikely(current->audit_context) && entryexit)
 525                 audit_syscall_exit(current, AUDITSC_RESULT(regs->regs[2]),
 526                                    regs->regs[2]);
 527
 528         if (!(current->ptrace & PT_PTRACED))
 529                 goto out;
 530         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 531                 goto out;
 532
 533         /* The 0x80 provides a way for the tracing parent to distinguish
 534            between a syscall stop and SIGTRAP delivery */
 535         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ?
 536                                  0x80 : 0));
 537
 538         /*
 539          * this isn't the same as continuing with a signal, but it will do
 540          * for normal use.  strace only continues with a signal if the
 541          * stopping signal is not SIGTRAP.  -brl
 542          */
 543         if (current->exit_code) {
 544                 send_sig(current->exit_code, current, 1);
 545                 current->exit_code = 0;
 546         }
 547  out:
 548         if (unlikely(current->audit_context) && !entryexit)
 549                 audit_syscall_entry(current, audit_arch(), regs->regs[2],
 550                                     regs->regs[4], regs->regs[5],
 551                                     regs->regs[6], regs->regs[7]);
 552 }