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