arch/s390/kernel/ptrace.c

   1 /*
   2  *  arch/s390/kernel/ptrace.c
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
   7  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   8  *
   9  *  Based on PowerPC version
  10  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  11  *
  12  *  Derived from "arch/m68k/kernel/ptrace.c"
  13  *  Copyright (C) 1994 by Hamish Macdonald
  14  *  Taken from linux/kernel/ptrace.c and modified for M680x0.
  15  *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
  16  *
  17  * Modified by Cort Dougan (cort@cs.nmt.edu)
  18  *
  19  *
  20  * This file is subject to the terms and conditions of the GNU General
  21  * Public License.  See the file README.legal in the main directory of
  22  * this archive for more details.
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/sched.h>
  27 #include <linux/mm.h>
  28 #include <linux/smp.h>
  29 #include <linux/smp_lock.h>
  30 #include <linux/errno.h>
  31 #include <linux/ptrace.h>
  32 #include <linux/user.h>
  33 #include <linux/security.h>
  34 #include <linux/audit.h>
  35 #include <linux/signal.h>
  36
  37 #include <asm/segment.h>
  38 #include <asm/page.h>
  39 #include <asm/pgtable.h>
  40 #include <asm/pgalloc.h>
  41 #include <asm/system.h>
  42 #include <asm/uaccess.h>
  43
  44 #ifdef CONFIG_S390_SUPPORT
  45 #include "compat_ptrace.h"
  46 #endif
  47
  48 static void
  49 FixPerRegisters(struct task_struct *task)
  50 {
  51         struct pt_regs *regs;
  52         per_struct *per_info;
  53
  54         regs = __KSTK_PTREGS(task);
  55         per_info = (per_struct *) &task->thread.per_info;
  56         per_info->control_regs.bits.em_instruction_fetch =
  57                 per_info->single_step | per_info->instruction_fetch;
  58
  59         if (per_info->single_step) {
  60                 per_info->control_regs.bits.starting_addr = 0;
  61 #ifdef CONFIG_S390_SUPPORT
  62                 if (test_thread_flag(TIF_31BIT))
  63                         per_info->control_regs.bits.ending_addr = 0x7fffffffUL;
  64                 else
  65 #endif
  66                         per_info->control_regs.bits.ending_addr = PSW_ADDR_INSN;
  67         } else {
  68                 per_info->control_regs.bits.starting_addr =
  69                         per_info->starting_addr;
  70                 per_info->control_regs.bits.ending_addr =
  71                         per_info->ending_addr;
  72         }
  73         /*
  74          * if any of the control reg tracing bits are on
  75          * we switch on per in the psw
  76          */
  77         if (per_info->control_regs.words.cr[0] & PER_EM_MASK)
  78                 regs->psw.mask |= PSW_MASK_PER;
  79         else
  80                 regs->psw.mask &= ~PSW_MASK_PER;
  81
  82         if (per_info->control_regs.bits.em_storage_alteration)
  83                 per_info->control_regs.bits.storage_alt_space_ctl = 1;
  84         else
  85                 per_info->control_regs.bits.storage_alt_space_ctl = 0;
  86 }
  87
  88 void
  89 set_single_step(struct task_struct *task)
  90 {
  91         task->thread.per_info.single_step = 1;
  92         FixPerRegisters(task);
  93 }
  94
  95 void
  96 clear_single_step(struct task_struct *task)
  97 {
  98         task->thread.per_info.single_step = 0;
  99         FixPerRegisters(task);
 100 }
 101
 102 /*
 103  * Called by kernel/ptrace.c when detaching..
 104  *
 105  * Make sure single step bits etc are not set.
 106  */
 107 void
 108 ptrace_disable(struct task_struct *child)
 109 {
 110         /* make sure the single step bit is not set. */
 111         clear_single_step(child);
 112 }
 113
 114 #ifndef CONFIG_ARCH_S390X
 115 # define __ADDR_MASK 3
 116 #else
 117 # define __ADDR_MASK 7
 118 #endif
 119
 120 /*
 121  * Read the word at offset addr from the user area of a process. The
 122  * trouble here is that the information is littered over different
 123  * locations. The process registers are found on the kernel stack,
 124  * the floating point stuff and the trace settings are stored in
 125  * the task structure. In addition the different structures in
 126  * struct user contain pad bytes that should be read as zeroes.
 127  * Lovely...
 128  */
 129 static int
 130 peek_user(struct task_struct *child, addr_t addr, addr_t data)
 131 {
 132         struct user *dummy = NULL;
 133         addr_t offset, tmp;
 134
 135         /*
 136          * Stupid gdb peeks/pokes the access registers in 64 bit with
 137          * an alignment of 4. Programmers from hell...
 138          */
 139         if ((addr & 3) || addr > sizeof(struct user) - __ADDR_MASK)
 140                 return -EIO;
 141
 142         if (addr < (addr_t) &dummy->regs.acrs) {
 143                 /*
 144                  * psw and gprs are stored on the stack
 145                  */
 146                 tmp = *(addr_t *)((addr_t) &__KSTK_PTREGS(child)->psw + addr);
 147                 if (addr == (addr_t) &dummy->regs.psw.mask)
 148                         /* Remove per bit from user psw. */
 149                         tmp &= ~PSW_MASK_PER;
 150
 151         } else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
 152                 /*
 153                  * access registers are stored in the thread structure
 154                  */
 155                 offset = addr - (addr_t) &dummy->regs.acrs;
 156                 tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);
 157
 158         } else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
 159                 /*
 160                  * orig_gpr2 is stored on the kernel stack
 161                  */
 162                 tmp = (addr_t) __KSTK_PTREGS(child)->orig_gpr2;
 163
 164         } else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
 165                 /*
 166                  * floating point regs. are stored in the thread structure
 167                  */
 168                 offset = addr - (addr_t) &dummy->regs.fp_regs;
 169                 tmp = *(addr_t *)((addr_t) &child->thread.fp_regs + offset);
 170
 171         } else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
 172                 /*
 173                  * per_info is found in the thread structure
 174                  */
 175                 offset = addr - (addr_t) &dummy->regs.per_info;
 176                 tmp = *(addr_t *)((addr_t) &child->thread.per_info + offset);
 177
 178         } else
 179                 tmp = 0;
 180
 181         return put_user(tmp, (addr_t __user *) data);
 182 }
 183
 184 /*
 185  * Write a word to the user area of a process at location addr. This
 186  * operation does have an additional problem compared to peek_user.
 187  * Stores to the program status word and on the floating point
 188  * control register needs to get checked for validity.
 189  */
 190 static int
 191 poke_user(struct task_struct *child, addr_t addr, addr_t data)
 192 {
 193         struct user *dummy = NULL;
 194         addr_t offset;
 195
 196         /*
 197          * Stupid gdb peeks/pokes the access registers in 64 bit with
 198          * an alignment of 4. Programmers from hell indeed...
 199          */
 200         if ((addr & 3) || addr > sizeof(struct user) - __ADDR_MASK)
 201                 return -EIO;
 202
 203         if (addr < (addr_t) &dummy->regs.acrs) {
 204                 /*
 205                  * psw and gprs are stored on the stack
 206                  */
 207                 if (addr == (addr_t) &dummy->regs.psw.mask &&
 208 #ifdef CONFIG_S390_SUPPORT
 209                     data != PSW_MASK_MERGE(PSW_USER32_BITS, data) &&
 210 #endif
 211                     data != PSW_MASK_MERGE(PSW_USER_BITS, data))
 212                         /* Invalid psw mask. */
 213                         return -EINVAL;
 214 #ifndef CONFIG_ARCH_S390X
 215                 if (addr == (addr_t) &dummy->regs.psw.addr)
 216                         /* I'd like to reject addresses without the
 217                            high order bit but older gdb's rely on it */
 218                         data |= PSW_ADDR_AMODE;
 219 #endif
 220                 *(addr_t *)((addr_t) &__KSTK_PTREGS(child)->psw + addr) = data;
 221
 222         } else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
 223                 /*
 224                  * access registers are stored in the thread structure
 225                  */
 226                 offset = addr - (addr_t) &dummy->regs.acrs;
 227                 *(addr_t *)((addr_t) &child->thread.acrs + offset) = data;
 228
 229         } else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
 230                 /*
 231                  * orig_gpr2 is stored on the kernel stack
 232                  */
 233                 __KSTK_PTREGS(child)->orig_gpr2 = data;
 234
 235         } else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
 236                 /*
 237                  * floating point regs. are stored in the thread structure
 238                  */
 239                 if (addr == (addr_t) &dummy->regs.fp_regs.fpc &&
 240                     (data & ~FPC_VALID_MASK) != 0)
 241                         return -EINVAL;
 242                 offset = addr - (addr_t) &dummy->regs.fp_regs;
 243                 *(addr_t *)((addr_t) &child->thread.fp_regs + offset) = data;
 244
 245         } else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
 246                 /*
 247                  * per_info is found in the thread structure
 248                  */
 249                 offset = addr - (addr_t) &dummy->regs.per_info;
 250                 *(addr_t *)((addr_t) &child->thread.per_info + offset) = data;
 251
 252         }
 253
 254         FixPerRegisters(child);
 255         return 0;
 256 }
 257
 258 static int
 259 do_ptrace_normal(struct task_struct *child, long request, long addr, long data)
 260 {
 261         unsigned long tmp;
 262         ptrace_area parea;
 263         int copied, ret;
 264
 265         switch (request) {
 266         case PTRACE_PEEKTEXT:
 267         case PTRACE_PEEKDATA:
 268                 /* Remove high order bit from address (only for 31 bit). */
 269                 addr &= PSW_ADDR_INSN;
 270                 /* read word at location addr. */
 271                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 272                 if (copied != sizeof(tmp))
 273                         return -EIO;
 274                 return put_user(tmp, (unsigned long __user *) data);
 275
 276         case PTRACE_PEEKUSR:
 277                 /* read the word at location addr in the USER area. */
 278                 return peek_user(child, addr, data);
 279
 280         case PTRACE_POKETEXT:
 281         case PTRACE_POKEDATA:
 282                 /* Remove high order bit from address (only for 31 bit). */
 283                 addr &= PSW_ADDR_INSN;
 284                 /* write the word at location addr. */
 285                 copied = access_process_vm(child, addr, &data, sizeof(data),1);
 286                 if (copied != sizeof(data))
 287                         return -EIO;
 288                 return 0;
 289
 290         case PTRACE_POKEUSR:
 291                 /* write the word at location addr in the USER area */
 292                 return poke_user(child, addr, data);
 293
 294         case PTRACE_PEEKUSR_AREA:
 295         case PTRACE_POKEUSR_AREA:
 296                 if (copy_from_user(&parea, (void __user *) addr,
 297                                                         sizeof(parea)))
 298                         return -EFAULT;
 299                 addr = parea.kernel_addr;
 300                 data = parea.process_addr;
 301                 copied = 0;
 302                 while (copied < parea.len) {
 303                         if (request == PTRACE_PEEKUSR_AREA)
 304                                 ret = peek_user(child, addr, data);
 305                         else {
 306                                 addr_t tmp;
 307                                 if (get_user (tmp, (addr_t __user *) data))
 308                                         return -EFAULT;
 309                                 ret = poke_user(child, addr, tmp);
 310                         }
 311                         if (ret)
 312                                 return ret;
 313                         addr += sizeof(unsigned long);
 314                         data += sizeof(unsigned long);
 315                         copied += sizeof(unsigned long);
 316                 }
 317                 return 0;
 318         }
 319         return ptrace_request(child, request, addr, data);
 320 }
 321
 322 #ifdef CONFIG_S390_SUPPORT
 323 /*
 324  * Now the fun part starts... a 31 bit program running in the
 325  * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
 326  * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
 327  * to handle, the difference to the 64 bit versions of the requests
 328  * is that the access is done in multiples of 4 byte instead of
 329  * 8 bytes (sizeof(unsigned long) on 31/64 bit).
 330  * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
 331  * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
 332  * is a 31 bit program too, the content of struct user can be
 333  * emulated. A 31 bit program peeking into the struct user of
 334  * a 64 bit program is a no-no.
 335  */
 336
 337 /*
 338  * Same as peek_user but for a 31 bit program.
 339  */
 340 static int
 341 peek_user_emu31(struct task_struct *child, addr_t addr, addr_t data)
 342 {
 343         struct user32 *dummy32 = NULL;
 344         per_struct32 *dummy_per32 = NULL;
 345         addr_t offset;
 346         __u32 tmp;
 347
 348         if (!test_thread_flag(TIF_31BIT) ||
 349             (addr & 3) || addr > sizeof(struct user) - 3)
 350                 return -EIO;
 351
 352         if (addr < (addr_t) &dummy32->regs.acrs) {
 353                 /*
 354                  * psw and gprs are stored on the stack
 355                  */
 356                 if (addr == (addr_t) &dummy32->regs.psw.mask) {
 357                         /* Fake a 31 bit psw mask. */
 358                         tmp = (__u32)(__KSTK_PTREGS(child)->psw.mask >> 32);
 359                         tmp = PSW32_MASK_MERGE(PSW32_USER_BITS, tmp);
 360                 } else if (addr == (addr_t) &dummy32->regs.psw.addr) {
 361                         /* Fake a 31 bit psw address. */
 362                         tmp = (__u32) __KSTK_PTREGS(child)->psw.addr |
 363                                 PSW32_ADDR_AMODE31;
 364                 } else {
 365                         /* gpr 0-15 */
 366                         tmp = *(__u32 *)((addr_t) &__KSTK_PTREGS(child)->psw +
 367                                          addr*2 + 4);
 368                 }
 369         } else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
 370                 /*
 371                  * access registers are stored in the thread structure
 372                  */
 373                 offset = addr - (addr_t) &dummy32->regs.acrs;
 374                 tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);
 375
 376         } else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
 377                 /*
 378                  * orig_gpr2 is stored on the kernel stack
 379                  */
 380                 tmp = *(__u32*)((addr_t) &__KSTK_PTREGS(child)->orig_gpr2 + 4);
 381
 382         } else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
 383                 /*
 384                  * floating point regs. are stored in the thread structure
 385                  */
 386                 offset = addr - (addr_t) &dummy32->regs.fp_regs;
 387                 tmp = *(__u32 *)((addr_t) &child->thread.fp_regs + offset);
 388
 389         } else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
 390                 /*
 391                  * per_info is found in the thread structure
 392                  */
 393                 offset = addr - (addr_t) &dummy32->regs.per_info;
 394                 /* This is magic. See per_struct and per_struct32. */
 395                 if ((offset >= (addr_t) &dummy_per32->control_regs &&
 396                      offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
 397                     (offset >= (addr_t) &dummy_per32->starting_addr &&
 398                      offset <= (addr_t) &dummy_per32->ending_addr) ||
 399                     offset == (addr_t) &dummy_per32->lowcore.words.address)
 400                         offset = offset*2 + 4;
 401                 else
 402                         offset = offset*2;
 403                 tmp = *(__u32 *)((addr_t) &child->thread.per_info + offset);
 404
 405         } else
 406                 tmp = 0;
 407
 408         return put_user(tmp, (__u32 __user *) data);
 409 }
 410
 411 /*
 412  * Same as poke_user but for a 31 bit program.
 413  */
 414 static int
 415 poke_user_emu31(struct task_struct *child, addr_t addr, addr_t data)
 416 {
 417         struct user32 *dummy32 = NULL;
 418         per_struct32 *dummy_per32 = NULL;
 419         addr_t offset;
 420         __u32 tmp;
 421
 422         if (!test_thread_flag(TIF_31BIT) ||
 423             (addr & 3) || addr > sizeof(struct user32) - 3)
 424                 return -EIO;
 425
 426         tmp = (__u32) data;
 427
 428         if (addr < (addr_t) &dummy32->regs.acrs) {
 429                 /*
 430                  * psw, gprs, acrs and orig_gpr2 are stored on the stack
 431                  */
 432                 if (addr == (addr_t) &dummy32->regs.psw.mask) {
 433                         /* Build a 64 bit psw mask from 31 bit mask. */
 434                         if (tmp != PSW32_MASK_MERGE(PSW32_USER_BITS, tmp))
 435                                 /* Invalid psw mask. */
 436                                 return -EINVAL;
 437                         __KSTK_PTREGS(child)->psw.mask =
 438                                 PSW_MASK_MERGE(PSW_USER32_BITS, (__u64) tmp << 32);
 439                 } else if (addr == (addr_t) &dummy32->regs.psw.addr) {
 440                         /* Build a 64 bit psw address from 31 bit address. */
 441                         __KSTK_PTREGS(child)->psw.addr =
 442                                 (__u64) tmp & PSW32_ADDR_INSN;
 443                 } else {
 444                         /* gpr 0-15 */
 445                         *(__u32*)((addr_t) &__KSTK_PTREGS(child)->psw
 446                                   + addr*2 + 4) = tmp;
 447                 }
 448         } else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
 449                 /*
 450                  * access registers are stored in the thread structure
 451                  */
 452                 offset = addr - (addr_t) &dummy32->regs.acrs;
 453                 *(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;
 454
 455         } else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
 456                 /*
 457                  * orig_gpr2 is stored on the kernel stack
 458                  */
 459                 *(__u32*)((addr_t) &__KSTK_PTREGS(child)->orig_gpr2 + 4) = tmp;
 460
 461         } else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
 462                 /*
 463                  * floating point regs. are stored in the thread structure
 464                  */
 465                 if (addr == (addr_t) &dummy32->regs.fp_regs.fpc &&
 466                     (tmp & ~FPC_VALID_MASK) != 0)
 467                         /* Invalid floating point control. */
 468                         return -EINVAL;
 469                 offset = addr - (addr_t) &dummy32->regs.fp_regs;
 470                 *(__u32 *)((addr_t) &child->thread.fp_regs + offset) = tmp;
 471
 472         } else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
 473                 /*
 474                  * per_info is found in the thread structure.
 475                  */
 476                 offset = addr - (addr_t) &dummy32->regs.per_info;
 477                 /*
 478                  * This is magic. See per_struct and per_struct32.
 479                  * By incident the offsets in per_struct are exactly
 480                  * twice the offsets in per_struct32 for all fields.
 481                  * The 8 byte fields need special handling though,
 482                  * because the second half (bytes 4-7) is needed and
 483                  * not the first half.
 484                  */
 485                 if ((offset >= (addr_t) &dummy_per32->control_regs &&
 486                      offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
 487                     (offset >= (addr_t) &dummy_per32->starting_addr &&
 488                      offset <= (addr_t) &dummy_per32->ending_addr) ||
 489                     offset == (addr_t) &dummy_per32->lowcore.words.address)
 490                         offset = offset*2 + 4;
 491                 else
 492                         offset = offset*2;
 493                 *(__u32 *)((addr_t) &child->thread.per_info + offset) = tmp;
 494
 495         }
 496
 497         FixPerRegisters(child);
 498         return 0;
 499 }
 500
 501 static int
 502 do_ptrace_emu31(struct task_struct *child, long request, long addr, long data)
 503 {
 504         unsigned int tmp;  /* 4 bytes !! */
 505         ptrace_area_emu31 parea;
 506         int copied, ret;
 507
 508         switch (request) {
 509         case PTRACE_PEEKTEXT:
 510         case PTRACE_PEEKDATA:
 511                 /* read word at location addr. */
 512                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 513                 if (copied != sizeof(tmp))
 514                         return -EIO;
 515                 return put_user(tmp, (unsigned int __user *) data);
 516
 517         case PTRACE_PEEKUSR:
 518                 /* read the word at location addr in the USER area. */
 519                 return peek_user_emu31(child, addr, data);
 520
 521         case PTRACE_POKETEXT:
 522         case PTRACE_POKEDATA:
 523                 /* write the word at location addr. */
 524                 tmp = data;
 525                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 1);
 526                 if (copied != sizeof(tmp))
 527                         return -EIO;
 528                 return 0;
 529
 530         case PTRACE_POKEUSR:
 531                 /* write the word at location addr in the USER area */
 532                 return poke_user_emu31(child, addr, data);
 533
 534         case PTRACE_PEEKUSR_AREA:
 535         case PTRACE_POKEUSR_AREA:
 536                 if (copy_from_user(&parea, (void __user *) addr,
 537                                                         sizeof(parea)))
 538                         return -EFAULT;
 539                 addr = parea.kernel_addr;
 540                 data = parea.process_addr;
 541                 copied = 0;
 542                 while (copied < parea.len) {
 543                         if (request == PTRACE_PEEKUSR_AREA)
 544                                 ret = peek_user_emu31(child, addr, data);
 545                         else {
 546                                 __u32 tmp;
 547                                 if (get_user (tmp, (__u32 __user *) data))
 548                                         return -EFAULT;
 549                                 ret = poke_user_emu31(child, addr, tmp);
 550                         }
 551                         if (ret)
 552                                 return ret;
 553                         addr += sizeof(unsigned int);
 554                         data += sizeof(unsigned int);
 555                         copied += sizeof(unsigned int);
 556                 }
 557                 return 0;
 558         case PTRACE_GETEVENTMSG:
 559                 return put_user((__u32) child->ptrace_message,
 560                                 (unsigned int __user *) data);
 561         case PTRACE_GETSIGINFO:
 562                 if (child->last_siginfo == NULL)
 563                         return -EINVAL;
 564                 return copy_siginfo_to_user32((compat_siginfo_t __user *) data,
 565                                               child->last_siginfo);
 566         case PTRACE_SETSIGINFO:
 567                 if (child->last_siginfo == NULL)
 568                         return -EINVAL;
 569                 return copy_siginfo_from_user32(child->last_siginfo,
 570                                                 (compat_siginfo_t __user *) data);
 571         }
 572         return ptrace_request(child, request, addr, data);
 573 }
 574 #endif
 575
 576 #define PT32_IEEE_IP 0x13c
 577
 578 static int
 579 do_ptrace(struct task_struct *child, long request, long addr, long data)
 580 {
 581         int ret;
 582
 583         if (request == PTRACE_ATTACH)
 584                 return ptrace_attach(child);
 585
 586         /*
 587          * Special cases to get/store the ieee instructions pointer.
 588          */
 589         if (child == current) {
 590                 if (request == PTRACE_PEEKUSR && addr == PT_IEEE_IP)
 591                         return peek_user(child, addr, data);
 592                 if (request == PTRACE_POKEUSR && addr == PT_IEEE_IP)
 593                         return poke_user(child, addr, data);
 594 #ifdef CONFIG_S390_SUPPORT
 595                 if (request == PTRACE_PEEKUSR &&
 596                     addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
 597                         return peek_user_emu31(child, addr, data);
 598                 if (request == PTRACE_POKEUSR &&
 599                     addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
 600                         return poke_user_emu31(child, addr, data);
 601 #endif
 602         }
 603
 604         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 605         if (ret < 0)
 606                 return ret;
 607
 608         switch (request) {
 609         case PTRACE_SYSCALL:
 610                 /* continue and stop at next (return from) syscall */
 611         case PTRACE_CONT:
 612                 /* restart after signal. */
 613                 if (!valid_signal(data))
 614                         return -EIO;
 615                 if (request == PTRACE_SYSCALL)
 616                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 617                 else
 618                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 619                 child->exit_code = data;
 620                 /* make sure the single step bit is not set. */
 621                 clear_single_step(child);
 622                 wake_up_process(child);
 623                 return 0;
 624
 625         case PTRACE_KILL:
 626                 /*
 627                  * make the child exit.  Best I can do is send it a sigkill.
 628                  * perhaps it should be put in the status that it wants to
 629                  * exit.
 630                  */
 631                 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
 632                         return 0;
 633                 child->exit_code = SIGKILL;
 634                 /* make sure the single step bit is not set. */
 635                 clear_single_step(child);
 636                 wake_up_process(child);
 637                 return 0;
 638
 639         case PTRACE_SINGLESTEP:
 640                 /* set the trap flag. */
 641                 if (!valid_signal(data))
 642                         return -EIO;
 643                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 644                 child->exit_code = data;
 645                 if (data)
 646                         set_tsk_thread_flag(child, TIF_SINGLE_STEP);
 647                 else
 648                         set_single_step(child);
 649                 /* give it a chance to run. */
 650                 wake_up_process(child);
 651                 return 0;
 652
 653         case PTRACE_DETACH:
 654                 /* detach a process that was attached. */
 655                 return ptrace_detach(child, data);
 656
 657
 658         /* Do requests that differ for 31/64 bit */
 659         default:
 660 #ifdef CONFIG_S390_SUPPORT
 661                 if (test_thread_flag(TIF_31BIT))
 662                         return do_ptrace_emu31(child, request, addr, data);
 663 #endif
 664                 return do_ptrace_normal(child, request, addr, data);
 665         }
 666         /* Not reached.  */
 667         return -EIO;
 668 }
 669
 670 asmlinkage long
 671 sys_ptrace(long request, long pid, long addr, long data)
 672 {
 673         struct task_struct *child;
 674         int ret;
 675
 676         lock_kernel();
 677
 678         if (request == PTRACE_TRACEME) {
 679                 /* are we already being traced? */
 680                 ret = -EPERM;
 681                 if (current->ptrace & PT_PTRACED)
 682                         goto out;
 683                 ret = security_ptrace(current->parent, current);
 684                 if (ret)
 685                         goto out;
 686                 /* set the ptrace bit in the process flags. */
 687                 current->ptrace |= PT_PTRACED;
 688                 goto out;
 689         }
 690
 691         ret = -EPERM;
 692         if (pid == 1)           /* you may not mess with init */
 693                 goto out;
 694
 695         ret = -ESRCH;
 696         read_lock(&tasklist_lock);
 697         child = find_task_by_pid(pid);
 698         if (child)
 699                 get_task_struct(child);
 700         read_unlock(&tasklist_lock);
 701         if (!child)
 702                 goto out;
 703
 704         ret = do_ptrace(child, request, addr, data);
 705
 706         put_task_struct(child);
 707 out:
 708         unlock_kernel();
 709         return ret;
 710 }
 711
 712 asmlinkage void
 713 syscall_trace(struct pt_regs *regs, int entryexit)
 714 {
 715         if (unlikely(current->audit_context) && entryexit)
 716                 audit_syscall_exit(current, AUDITSC_RESULT(regs->gprs[2]), regs->gprs[2]);
 717
 718         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 719                 goto out;
 720         if (!(current->ptrace & PT_PTRACED))
 721                 goto out;
 722         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 723                                  ? 0x80 : 0));
 724
 725         /*
 726          * this isn't the same as continuing with a signal, but it will do
 727          * for normal use.  strace only continues with a signal if the
 728          * stopping signal is not SIGTRAP.  -brl
 729          */
 730         if (current->exit_code) {
 731                 send_sig(current->exit_code, current, 1);
 732                 current->exit_code = 0;
 733         }
 734  out:
 735         if (unlikely(current->audit_context) && !entryexit)
 736                 audit_syscall_entry(current,
 737                                     test_thread_flag(TIF_31BIT)?AUDIT_ARCH_S390:AUDIT_ARCH_S390X,
 738                                     regs->gprs[2], regs->orig_gpr2, regs->gprs[3],
 739                                     regs->gprs[4], regs->gprs[5]);
 740 }