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