arch/mips64/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  * Copyright (C) 2000 Ulf Carlsson
  11  *
  12  * At this time Linux/MIPS64 only supports syscall tracing, even for 32-bit
  13  * binaries.
  14  */
  15 #include <linux/config.h>
  16 #include <linux/kernel.h>
  17 #include <linux/sched.h>
  18 #include <linux/mm.h>
  19 #include <linux/errno.h>
  20 #include <linux/ptrace.h>
  21 #include <linux/smp.h>
  22 #include <linux/smp_lock.h>
  23 #include <linux/user.h>
  24 #include <linux/security.h>
  25
  26 #include <asm/cpu.h>
  27 #include <asm/fpu.h>
  28 #include <asm/mipsregs.h>
  29 #include <asm/pgtable.h>
  30 #include <asm/page.h>
  31 #include <asm/system.h>
  32 #include <asm/uaccess.h>
  33 #include <asm/bootinfo.h>
  34
  35 /*
  36  * Called by kernel/ptrace.c when detaching..
  37  *
  38  * Make sure single step bits etc are not set.
  39  */
  40 void ptrace_disable(struct task_struct *child)
  41 {
  42         /* Nothing to do.. */
  43 }
  44
  45 /*
  46  * Tracing a 32-bit process with a 64-bit strace and vice versa will not
  47  * work.  I don't know how to fix this.
  48  */
  49 asmlinkage int sys32_ptrace(int request, int pid, int addr, int data)
  50 {
  51         struct task_struct *child;
  52         int ret;
  53
  54         lock_kernel();
  55         ret = -EPERM;
  56         if (request == PTRACE_TRACEME) {
  57                 /* are we already being traced? */
  58                 if (current->ptrace & PT_PTRACED)
  59                         goto out;
  60                 if ((ret = security_ptrace(current->parent, current)))
  61                         goto out;
  62                 /* set the ptrace bit in the process flags. */
  63                 current->ptrace |= PT_PTRACED;
  64                 ret = 0;
  65                 goto out;
  66         }
  67         ret = -ESRCH;
  68         read_lock(&tasklist_lock);
  69         child = find_task_by_pid(pid);
  70         if (child)
  71                 get_task_struct(child);
  72         read_unlock(&tasklist_lock);
  73         if (!child)
  74                 goto out;
  75
  76         ret = -EPERM;
  77         if (pid == 1)           /* you may not mess with init */
  78                 goto out_tsk;
  79
  80         if (request == PTRACE_ATTACH) {
  81                 ret = ptrace_attach(child);
  82                 goto out_tsk;
  83         }
  84
  85         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  86         if (ret < 0)
  87                 goto out_tsk;
  88
  89         switch (request) {
  90         /* when I and D space are separate, these will need to be fixed. */
  91         case PTRACE_PEEKTEXT: /* read word at location addr. */
  92         case PTRACE_PEEKDATA: {
  93                 unsigned int tmp;
  94                 int copied;
  95
  96                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  97                 ret = -EIO;
  98                 if (copied != sizeof(tmp))
  99                         break;
 100                 ret = put_user(tmp, (unsigned int *) (unsigned long) data);
 101                 break;
 102         }
 103
 104         /* read the word at location addr in the USER area. */
 105         case PTRACE_PEEKUSR: {
 106                 struct pt_regs *regs;
 107                 unsigned int tmp;
 108
 109                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 110                         KERNEL_STACK_SIZE - 32 - sizeof(struct pt_regs));
 111                 ret = 0;
 112
 113                 switch (addr) {
 114                 case 0 ... 31:
 115                         tmp = regs->regs[addr];
 116                         break;
 117                 case FPR_BASE ... FPR_BASE + 31:
 118                         if (child->used_math) {
 119                                 unsigned long long *fregs;
 120                                 fregs = (unsigned long long *)get_fpu_regs(child);
 121                                 /*
 122                                  * The odd registers are actually the high
 123                                  * order bits of the values stored in the even
 124                                  * registers - unless we're using r2k_switch.S.
 125                                  */
 126                                 if (addr & 1)
 127                                         tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
 128                                 else
 129                                         tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
 130                         } else {
 131                                 tmp = -1;       /* FP not yet used  */
 132                         }
 133                         break;
 134                 case PC:
 135                         tmp = regs->cp0_epc;
 136                         break;
 137                 case CAUSE:
 138                         tmp = regs->cp0_cause;
 139                         break;
 140                 case BADVADDR:
 141                         tmp = regs->cp0_badvaddr;
 142                         break;
 143                 case MMHI:
 144                         tmp = regs->hi;
 145                         break;
 146                 case MMLO:
 147                         tmp = regs->lo;
 148                         break;
 149                 case FPC_CSR:
 150                         if (cpu_has_fpu)
 151                                 tmp = child->thread.fpu.hard.control;
 152                         else
 153                                 tmp = child->thread.fpu.soft.sr;
 154                         break;
 155                 case FPC_EIR: { /* implementation / version register */
 156                         unsigned int flags;
 157                         flags = read_c0_status();
 158                         __enable_fpu();
 159                         __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 160                         write_c0_status(flags);
 161                         break;
 162                 }
 163                 default:
 164                         tmp = 0;
 165                         ret = -EIO;
 166                         goto out_tsk;
 167                 }
 168                 ret = put_user(tmp, (unsigned *) (unsigned long) data);
 169                 break;
 170                 }
 171         /* when I and D space are separate, this will have to be fixed. */
 172         case PTRACE_POKETEXT: /* write the word at location addr. */
 173         case PTRACE_POKEDATA:
 174                 ret = 0;
 175                 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 176                         break;
 177                 ret = -EIO;
 178                 break;
 179
 180         case PTRACE_POKEUSR: {
 181                 struct pt_regs *regs;
 182                 ret = 0;
 183                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 184                         KERNEL_STACK_SIZE - 32 - sizeof(struct pt_regs));
 185
 186                 switch (addr) {
 187                 case 0 ... 31:
 188                         regs->regs[addr] = data;
 189                         break;
 190                 case FPR_BASE ... FPR_BASE + 31: {
 191                         unsigned long long *fregs;
 192                         fregs = (unsigned long long *)get_fpu_regs(child);
 193                         if (!child->used_math) {
 194                                 /* FP not yet used  */
 195                                 memset(&child->thread.fpu.hard, ~0,
 196                                        sizeof(child->thread.fpu.hard));
 197                                 child->thread.fpu.hard.control = 0;
 198                         }
 199                         /*
 200                          * The odd registers are actually the high order bits
 201                          * of the values stored in the even registers - unless
 202                          * we're using r2k_switch.S.
 203                          */
 204                         if (addr & 1) {
 205                                 fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
 206                                 fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
 207                         } else {
 208                                 fregs[addr - FPR_BASE] &= ~0xffffffffLL;
 209                                 /* Must cast, lest sign extension fill upper
 210                                    bits!  */
 211                                 fregs[addr - FPR_BASE] |= (unsigned int)data;
 212                         }
 213                         break;
 214                 }
 215                 case PC:
 216                         regs->cp0_epc = data;
 217                         break;
 218                 case MMHI:
 219                         regs->hi = data;
 220                         break;
 221                 case MMLO:
 222                         regs->lo = data;
 223                         break;
 224                 case FPC_CSR:
 225                         if (cpu_has_fpu)
 226                                 child->thread.fpu.hard.control = data;
 227                         else
 228                                 child->thread.fpu.soft.sr = data;
 229                         break;
 230                 default:
 231                         /* The rest are not allowed. */
 232                         ret = -EIO;
 233                         break;
 234                 }
 235                 break;
 236                 }
 237         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 238         case PTRACE_CONT: { /* restart after signal. */
 239                 ret = -EIO;
 240                 if ((unsigned int) data > _NSIG)
 241                         break;
 242                 if (request == PTRACE_SYSCALL) {
 243                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 244                 }
 245                 else {
 246                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 247                 }
 248                 child->exit_code = data;
 249                 wake_up_process(child);
 250                 ret = 0;
 251                 break;
 252         }
 253
 254 /*
 255  * make the child exit.  Best I can do is send it a sigkill.
 256  * perhaps it should be put in the status that it wants to
 257  * exit.
 258  */
 259         case PTRACE_KILL: {
 260                 if (child->state == TASK_ZOMBIE)        /* already dead */
 261                         break;
 262                 child->exit_code = SIGKILL;
 263                 wake_up_process(child);
 264                 break;
 265         }
 266
 267         case PTRACE_DETACH: /* detach a process that was attached. */
 268                 ret = ptrace_detach(child, data);
 269                 break;
 270
 271         default:
 272                 ret = ptrace_request(child, request, addr, data);
 273                 break;
 274         }
 275
 276 out_tsk:
 277         put_task_struct(child);
 278 out:
 279         unlock_kernel();
 280         return ret;
 281 }
 282
 283 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 284 {
 285         struct task_struct *child;
 286         int ret;
 287
 288         lock_kernel();
 289 #if 0
 290         printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n",
 291                (int) request, (int) pid, (unsigned long) addr,
 292                (unsigned long) data);
 293 #endif
 294         ret = -EPERM;
 295         if (request == PTRACE_TRACEME) {
 296                 /* are we already being traced? */
 297                 if (current->ptrace & PT_PTRACED)
 298                         goto out;
 299                 if ((ret = security_ptrace(current->parent, current)))
 300                         goto out;
 301                 /* set the ptrace bit in the process flags. */
 302                 current->ptrace |= PT_PTRACED;
 303                 ret = 0;
 304                 goto out;
 305         }
 306         ret = -ESRCH;
 307         read_lock(&tasklist_lock);
 308         child = find_task_by_pid(pid);
 309         if (child)
 310                 get_task_struct(child);
 311         read_unlock(&tasklist_lock);
 312         if (!child)
 313                 goto out;
 314
 315         ret = -EPERM;
 316         if (pid == 1)           /* you may not mess with init */
 317                 goto out_tsk;
 318
 319         if (request == PTRACE_ATTACH) {
 320                 ret = ptrace_attach(child);
 321                 goto out_tsk;
 322         }
 323
 324         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 325         if (ret < 0)
 326                 goto out_tsk;
 327
 328         switch (request) {
 329         /* when I and D space are separate, these will need to be fixed. */
 330         case PTRACE_PEEKTEXT: /* read word at location addr. */
 331         case PTRACE_PEEKDATA: {
 332                 unsigned long tmp;
 333                 int copied;
 334
 335                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 336                 ret = -EIO;
 337                 if (copied != sizeof(tmp))
 338                         break;
 339                 ret = put_user(tmp,(unsigned long *) data);
 340                 break;
 341         }
 342
 343         /* read the word at location addr in the USER area. */
 344         case PTRACE_PEEKUSR: {
 345                 struct pt_regs *regs;
 346                 unsigned long tmp;
 347
 348                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 349                         KERNEL_STACK_SIZE - 32 - sizeof(struct pt_regs));
 350                 ret = 0;
 351
 352                 switch (addr) {
 353                 case 0 ... 31:
 354                         tmp = regs->regs[addr];
 355                         break;
 356                 case FPR_BASE ... FPR_BASE + 31:
 357                         if (child->used_math) {
 358                                 unsigned long *fregs = get_fpu_regs(child);
 359                                 tmp = fregs[addr - FPR_BASE];
 360                         } else {
 361                                 tmp = -EIO;
 362                         }
 363                         break;
 364                 case PC:
 365                         tmp = regs->cp0_epc;
 366                         break;
 367                 case CAUSE:
 368                         tmp = regs->cp0_cause;
 369                         break;
 370                 case BADVADDR:
 371                         tmp = regs->cp0_badvaddr;
 372                         break;
 373                 case MMHI:
 374                         tmp = regs->hi;
 375                         break;
 376                 case MMLO:
 377                         tmp = regs->lo;
 378                         break;
 379                 case FPC_CSR:
 380                         if (cpu_has_fpu)
 381                                 tmp = child->thread.fpu.hard.control;
 382                         else
 383                                 tmp = child->thread.fpu.soft.sr;
 384                         break;
 385                 case FPC_EIR: { /* implementation / version register */
 386                         unsigned int flags;
 387                         flags = read_c0_status();
 388                         __enable_fpu();
 389                         __asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
 390                         write_c0_status(flags);
 391                         break;
 392                 }
 393                 default:
 394                         tmp = 0;
 395                         ret = -EIO;
 396                         goto out_tsk;
 397                 }
 398                 ret = put_user(tmp, (unsigned long *) data);
 399                 break;
 400                 }
 401         /* when I and D space are separate, this will have to be fixed. */
 402         case PTRACE_POKETEXT: /* write the word at location addr. */
 403         case PTRACE_POKEDATA:
 404                 ret = 0;
 405                 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
 406                         break;
 407                 ret = -EIO;
 408                 break;
 409
 410         case PTRACE_POKEUSR: {
 411                 struct pt_regs *regs;
 412                 ret = 0;
 413                 regs = (struct pt_regs *) ((unsigned long) child->thread_info +
 414                         KERNEL_STACK_SIZE - 32 - sizeof(struct pt_regs));
 415
 416                 switch (addr) {
 417                 case 0 ... 31:
 418                         regs->regs[addr] = data;
 419                         break;
 420                 case FPR_BASE ... FPR_BASE + 31: {
 421                         unsigned long *fregs = get_fpu_regs(child);
 422                         if (!child->used_math) {
 423                                 /* FP not yet used  */
 424                                 memset(&child->thread.fpu.hard, ~0,
 425                                        sizeof(child->thread.fpu.hard));
 426                                 child->thread.fpu.hard.control = 0;
 427                         }
 428                         fregs[addr - FPR_BASE] = data;
 429                         break;
 430                 }
 431                 case PC:
 432                         regs->cp0_epc = data;
 433                         break;
 434                 case MMHI:
 435                         regs->hi = data;
 436                         break;
 437                 case MMLO:
 438                         regs->lo = data;
 439                         break;
 440                 case FPC_CSR:
 441                         if (cpu_has_fpu)
 442                                 child->thread.fpu.hard.control = data;
 443                         else
 444                                 child->thread.fpu.soft.sr = data;
 445                         break;
 446                 default:
 447                         /* The rest are not allowed. */
 448                         ret = -EIO;
 449                         break;
 450                 }
 451                 break;
 452                 }
 453         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 454         case PTRACE_CONT: { /* restart after signal. */
 455                 ret = -EIO;
 456                 if ((unsigned long) data > _NSIG)
 457                         break;
 458                 if (request == PTRACE_SYSCALL) {
 459                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 460                 }
 461                 else {
 462                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 463                 }
 464                 child->exit_code = data;
 465                 wake_up_process(child);
 466                 ret = 0;
 467                 break;
 468         }
 469
 470 /*
 471  * make the child exit.  Best I can do is send it a sigkill.
 472  * perhaps it should be put in the status that it wants to
 473  * exit.
 474  */
 475         case PTRACE_KILL: {
 476                 if (child->state == TASK_ZOMBIE)        /* already dead */
 477                         break;
 478                 child->exit_code = SIGKILL;
 479                 wake_up_process(child);
 480                 break;
 481         }
 482
 483         case PTRACE_DETACH: /* detach a process that was attached. */
 484                 ret = ptrace_detach(child, data);
 485                 break;
 486
 487         default:
 488                 ret = ptrace_request(child, request, addr, data);
 489                 break;
 490         }
 491
 492 out_tsk:
 493         put_task_struct(child);
 494 out:
 495         unlock_kernel();
 496         return ret;
 497 }
 498
 499 struct task_work_bf {
 500 #ifdef __MIPSEB__
 501         signed          need_resched  :8;
 502         unsigned        syscall_trace;  /* count of syscall interceptors */
 503         unsigned        sigpending;
 504         unsigned        notify_resume;  /* request for notification on
 505                                            userspace execution resumption */
 506 #endif
 507 #ifdef __MIPSEL__
 508         unsigned        notify_resume : 8;      /* request for notification on
 509                                                    userspace execution
 510                                                    resumption */
 511         unsigned        sigpending    : 8;
 512         unsigned        syscall_trace : 8;      /* count of syscall
 513                                                    interceptors */
 514         signed          need_resched : 8;
 515 #endif
 516 };
 517
 518 asmlinkage void do_syscall_trace(void)
 519 {
 520         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 521                 return;
 522         if (!(current->ptrace & PT_PTRACED))
 523                 return;
 524
 525         /* The 0x80 provides a way for the tracing parent to distinguish
 526            between a syscall stop and SIGTRAP delivery */
 527         current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 528                                         ? 0x80 : 0);
 529         preempt_disable();
 530         current->state = TASK_STOPPED;
 531         notify_parent(current, SIGCHLD);
 532         schedule();
 533         preempt_enable();
 534         /*
 535          * this isn't the same as continuing with a signal, but it will do
 536          * for normal use.  strace only continues with a signal if the
 537          * stopping signal is not SIGTRAP.  -brl
 538          */
 539         if (current->exit_code) {
 540                 send_sig(current->exit_code, current, 1);
 541                 current->exit_code = 0;
 542         }
 543 }