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