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 #include <asm/unistd.h>
  44
  45 #ifdef CONFIG_S390_SUPPORT
  46 #include "compat_ptrace.h"
  47 #endif
  48
  49 static void
  50 FixPerRegisters(struct task_struct *task)
  51 {
  52         struct pt_regs *regs;
  53         per_struct *per_info;
  54
  55         regs = __KSTK_PTREGS(task);
  56         per_info = (per_struct *) &task->thread.per_info;
  57         per_info->control_regs.bits.em_instruction_fetch =
  58                 per_info->single_step | per_info->instruction_fetch;
  59
  60         if (per_info->single_step) {
  61                 per_info->control_regs.bits.starting_addr = 0;
  62 #ifdef CONFIG_S390_SUPPORT
  63                 if (test_thread_flag(TIF_31BIT))
  64                         per_info->control_regs.bits.ending_addr = 0x7fffffffUL;
  65                 else
  66 #endif
  67                         per_info->control_regs.bits.ending_addr = PSW_ADDR_INSN;
  68         } else {
  69                 per_info->control_regs.bits.starting_addr =
  70                         per_info->starting_addr;
  71                 per_info->control_regs.bits.ending_addr =
  72                         per_info->ending_addr;
  73         }
  74         /*
  75          * if any of the control reg tracing bits are on
  76          * we switch on per in the psw
  77          */
  78         if (per_info->control_regs.words.cr[0] & PER_EM_MASK)
  79                 regs->psw.mask |= PSW_MASK_PER;
  80         else
  81                 regs->psw.mask &= ~PSW_MASK_PER;
  82
  83         if (per_info->control_regs.bits.em_storage_alteration)
  84                 per_info->control_regs.bits.storage_alt_space_ctl = 1;
  85         else
  86                 per_info->control_regs.bits.storage_alt_space_ctl = 0;
  87 }
  88
  89 void
  90 set_single_step(struct task_struct *task)
  91 {
  92         task->thread.per_info.single_step = 1;
  93         FixPerRegisters(task);
  94 }
  95
  96 void
  97 clear_single_step(struct task_struct *task)
  98 {
  99         task->thread.per_info.single_step = 0;
 100         FixPerRegisters(task);
 101 }
 102
 103 /*
 104  * Called by kernel/ptrace.c when detaching..
 105  *
 106  * Make sure single step bits etc are not set.
 107  */
 108 void
 109 ptrace_disable(struct task_struct *child)
 110 {
 111         /* make sure the single step bit is not set. */
 112         clear_single_step(child);
 113 }
 114
 115 #ifndef CONFIG_ARCH_S390X
 116 # define __ADDR_MASK 3
 117 #else
 118 # define __ADDR_MASK 7
 119 #endif
 120
 121 /*
 122  * Read the word at offset addr from the user area of a process. The
 123  * trouble here is that the information is littered over different
 124  * locations. The process registers are found on the kernel stack,
 125  * the floating point stuff and the trace settings are stored in
 126  * the task structure. In addition the different structures in
 127  * struct user contain pad bytes that should be read as zeroes.
 128  * Lovely...
 129  */
 130 static int
 131 peek_user(struct task_struct *child, addr_t addr, addr_t data)
 132 {
 133         struct user *dummy = NULL;
 134         addr_t offset, tmp, mask;
 135
 136         /*
 137          * Stupid gdb peeks/pokes the access registers in 64 bit with
 138          * an alignment of 4. Programmers from hell...
 139          */
 140         mask = __ADDR_MASK;
 141 #ifdef CONFIG_ARCH_S390X
 142         if (addr >= (addr_t) &dummy->regs.acrs &&
 143             addr < (addr_t) &dummy->regs.orig_gpr2)
 144                 mask = 3;
 145 #endif
 146         if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
 147                 return -EIO;
 148
 149         if (addr < (addr_t) &dummy->regs.acrs) {
 150                 /*
 151                  * psw and gprs are stored on the stack
 152                  */
 153                 tmp = *(addr_t *)((addr_t) &__KSTK_PTREGS(child)->psw + addr);
 154                 if (addr == (addr_t) &dummy->regs.psw.mask)
 155                         /* Remove per bit from user psw. */
 156                         tmp &= ~PSW_MASK_PER;
 157
 158         } else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
 159                 /*
 160                  * access registers are stored in the thread structure
 161                  */
 162                 offset = addr - (addr_t) &dummy->regs.acrs;
 163 #ifdef CONFIG_ARCH_S390X
 164                 /*
 165                  * Very special case: old & broken 64 bit gdb reading
 166                  * from acrs[15]. Result is a 64 bit value. Read the
 167                  * 32 bit acrs[15] value and shift it by 32. Sick...
 168                  */
 169                 if (addr == (addr_t) &dummy->regs.acrs[15])
 170                         tmp = ((unsigned long) child->thread.acrs[15]) << 32;
 171                 else
 172 #endif
 173                 tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);
 174
 175         } else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
 176                 /*
 177                  * orig_gpr2 is stored on the kernel stack
 178                  */
 179                 tmp = (addr_t) __KSTK_PTREGS(child)->orig_gpr2;
 180
 181         } else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
 182                 /*
 183                  * floating point regs. are stored in the thread structure
 184                  */
 185                 offset = addr - (addr_t) &dummy->regs.fp_regs;
 186                 tmp = *(addr_t *)((addr_t) &child->thread.fp_regs + offset);
 187                 if (addr == (addr_t) &dummy->regs.fp_regs.fpc)
 188                         tmp &= (unsigned long) FPC_VALID_MASK
 189                                 << (BITS_PER_LONG - 32);
 190
 191         } else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
 192                 /*
 193                  * per_info is found in the thread structure
 194                  */
 195                 offset = addr - (addr_t) &dummy->regs.per_info;
 196                 tmp = *(addr_t *)((addr_t) &child->thread.per_info + offset);
 197
 198         } else
 199                 tmp = 0;
 200
 201         return put_user(tmp, (addr_t __user *) data);
 202 }
 203
 204 /*
 205  * Write a word to the user area of a process at location addr. This
 206  * operation does have an additional problem compared to peek_user.
 207  * Stores to the program status word and on the floating point
 208  * control register needs to get checked for validity.
 209  */
 210 static int
 211 poke_user(struct task_struct *child, addr_t addr, addr_t data)
 212 {
 213         struct user *dummy = NULL;
 214         addr_t offset, mask;
 215
 216         /*
 217          * Stupid gdb peeks/pokes the access registers in 64 bit with
 218          * an alignment of 4. Programmers from hell indeed...
 219          */
 220         mask = __ADDR_MASK;
 221 #ifdef CONFIG_ARCH_S390X
 222         if (addr >= (addr_t) &dummy->regs.acrs &&
 223             addr < (addr_t) &dummy->regs.orig_gpr2)
 224                 mask = 3;
 225 #endif
 226         if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
 227                 return -EIO;
 228
 229         if (addr < (addr_t) &dummy->regs.acrs) {
 230                 /*
 231                  * psw and gprs are stored on the stack
 232                  */
 233                 if (addr == (addr_t) &dummy->regs.psw.mask &&
 234 #ifdef CONFIG_S390_SUPPORT
 235                     data != PSW_MASK_MERGE(PSW_USER32_BITS, data) &&
 236 #endif
 237                     data != PSW_MASK_MERGE(PSW_USER_BITS, data))
 238                         /* Invalid psw mask. */
 239                         return -EINVAL;
 240 #ifndef CONFIG_ARCH_S390X
 241                 if (addr == (addr_t) &dummy->regs.psw.addr)
 242                         /* I'd like to reject addresses without the
 243                            high order bit but older gdb's rely on it */
 244                         data |= PSW_ADDR_AMODE;
 245 #endif
 246                 *(addr_t *)((addr_t) &__KSTK_PTREGS(child)->psw + addr) = data;
 247
 248         } else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
 249                 /*
 250                  * access registers are stored in the thread structure
 251                  */
 252                 offset = addr - (addr_t) &dummy->regs.acrs;
 253 #ifdef CONFIG_ARCH_S390X
 254                 /*
 255                  * Very special case: old & broken 64 bit gdb writing
 256                  * to acrs[15] with a 64 bit value. Ignore the lower
 257                  * half of the value and write the upper 32 bit to
 258                  * acrs[15]. Sick...
 259                  */
 260                 if (addr == (addr_t) &dummy->regs.acrs[15])
 261                         child->thread.acrs[15] = (unsigned int) (data >> 32);
 262                 else
 263 #endif
 264                 *(addr_t *)((addr_t) &child->thread.acrs + offset) = data;
 265
 266         } else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
 267                 /*
 268                  * orig_gpr2 is stored on the kernel stack
 269                  */
 270                 __KSTK_PTREGS(child)->orig_gpr2 = data;
 271
 272         } else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
 273                 /*
 274                  * floating point regs. are stored in the thread structure
 275                  */
 276                 if (addr == (addr_t) &dummy->regs.fp_regs.fpc &&
 277                     (data & ~((unsigned long) FPC_VALID_MASK
 278                               << (BITS_PER_LONG - 32))) != 0)
 279                         return -EINVAL;
 280                 offset = addr - (addr_t) &dummy->regs.fp_regs;
 281                 *(addr_t *)((addr_t) &child->thread.fp_regs + offset) = data;
 282
 283         } else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
 284                 /*
 285                  * per_info is found in the thread structure
 286                  */
 287                 offset = addr - (addr_t) &dummy->regs.per_info;
 288                 *(addr_t *)((addr_t) &child->thread.per_info + offset) = data;
 289
 290         }
 291
 292         FixPerRegisters(child);
 293         return 0;
 294 }
 295
 296 static int
 297 do_ptrace_normal(struct task_struct *child, long request, long addr, long data)
 298 {
 299         unsigned long tmp;
 300         ptrace_area parea;
 301         int copied, ret;
 302
 303         switch (request) {
 304         case PTRACE_PEEKTEXT:
 305         case PTRACE_PEEKDATA:
 306                 /* Remove high order bit from address (only for 31 bit). */
 307                 addr &= PSW_ADDR_INSN;
 308                 /* read word at location addr. */
 309                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 310                 if (copied != sizeof(tmp))
 311                         return -EIO;
 312                 return put_user(tmp, (unsigned long __user *) data);
 313
 314         case PTRACE_PEEKUSR:
 315                 /* read the word at location addr in the USER area. */
 316                 return peek_user(child, addr, data);
 317
 318         case PTRACE_POKETEXT:
 319         case PTRACE_POKEDATA:
 320                 /* Remove high order bit from address (only for 31 bit). */
 321                 addr &= PSW_ADDR_INSN;
 322                 /* write the word at location addr. */
 323                 copied = access_process_vm(child, addr, &data, sizeof(data),1);
 324                 if (copied != sizeof(data))
 325                         return -EIO;
 326                 return 0;
 327
 328         case PTRACE_POKEUSR:
 329                 /* write the word at location addr in the USER area */
 330                 return poke_user(child, addr, data);
 331
 332         case PTRACE_PEEKUSR_AREA:
 333         case PTRACE_POKEUSR_AREA:
 334                 if (copy_from_user(&parea, (void __user *) addr,
 335                                                         sizeof(parea)))
 336                         return -EFAULT;
 337                 addr = parea.kernel_addr;
 338                 data = parea.process_addr;
 339                 copied = 0;
 340                 while (copied < parea.len) {
 341                         if (request == PTRACE_PEEKUSR_AREA)
 342                                 ret = peek_user(child, addr, data);
 343                         else {
 344                                 addr_t tmp;
 345                                 if (get_user (tmp, (addr_t __user *) data))
 346                                         return -EFAULT;
 347                                 ret = poke_user(child, addr, tmp);
 348                         }
 349                         if (ret)
 350                                 return ret;
 351                         addr += sizeof(unsigned long);
 352                         data += sizeof(unsigned long);
 353                         copied += sizeof(unsigned long);
 354                 }
 355                 return 0;
 356         }
 357         return ptrace_request(child, request, addr, data);
 358 }
 359
 360 #ifdef CONFIG_S390_SUPPORT
 361 /*
 362  * Now the fun part starts... a 31 bit program running in the
 363  * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
 364  * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
 365  * to handle, the difference to the 64 bit versions of the requests
 366  * is that the access is done in multiples of 4 byte instead of
 367  * 8 bytes (sizeof(unsigned long) on 31/64 bit).
 368  * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
 369  * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
 370  * is a 31 bit program too, the content of struct user can be
 371  * emulated. A 31 bit program peeking into the struct user of
 372  * a 64 bit program is a no-no.
 373  */
 374
 375 /*
 376  * Same as peek_user but for a 31 bit program.
 377  */
 378 static int
 379 peek_user_emu31(struct task_struct *child, addr_t addr, addr_t data)
 380 {
 381         struct user32 *dummy32 = NULL;
 382         per_struct32 *dummy_per32 = NULL;
 383         addr_t offset;
 384         __u32 tmp;
 385
 386         if (!test_thread_flag(TIF_31BIT) ||
 387             (addr & 3) || addr > sizeof(struct user) - 3)
 388                 return -EIO;
 389
 390         if (addr < (addr_t) &dummy32->regs.acrs) {
 391                 /*
 392                  * psw and gprs are stored on the stack
 393                  */
 394                 if (addr == (addr_t) &dummy32->regs.psw.mask) {
 395                         /* Fake a 31 bit psw mask. */
 396                         tmp = (__u32)(__KSTK_PTREGS(child)->psw.mask >> 32);
 397                         tmp = PSW32_MASK_MERGE(PSW32_USER_BITS, tmp);
 398                 } else if (addr == (addr_t) &dummy32->regs.psw.addr) {
 399                         /* Fake a 31 bit psw address. */
 400                         tmp = (__u32) __KSTK_PTREGS(child)->psw.addr |
 401                                 PSW32_ADDR_AMODE31;
 402                 } else {
 403                         /* gpr 0-15 */
 404                         tmp = *(__u32 *)((addr_t) &__KSTK_PTREGS(child)->psw +
 405                                          addr*2 + 4);
 406                 }
 407         } else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
 408                 /*
 409                  * access registers are stored in the thread structure
 410                  */
 411                 offset = addr - (addr_t) &dummy32->regs.acrs;
 412                 tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);
 413
 414         } else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
 415                 /*
 416                  * orig_gpr2 is stored on the kernel stack
 417                  */
 418                 tmp = *(__u32*)((addr_t) &__KSTK_PTREGS(child)->orig_gpr2 + 4);
 419
 420         } else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
 421                 /*
 422                  * floating point regs. are stored in the thread structure
 423                  */
 424                 offset = addr - (addr_t) &dummy32->regs.fp_regs;
 425                 tmp = *(__u32 *)((addr_t) &child->thread.fp_regs + offset);
 426
 427         } else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
 428                 /*
 429                  * per_info is found in the thread structure
 430                  */
 431                 offset = addr - (addr_t) &dummy32->regs.per_info;
 432                 /* This is magic. See per_struct and per_struct32. */
 433                 if ((offset >= (addr_t) &dummy_per32->control_regs &&
 434                      offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
 435                     (offset >= (addr_t) &dummy_per32->starting_addr &&
 436                      offset <= (addr_t) &dummy_per32->ending_addr) ||
 437                     offset == (addr_t) &dummy_per32->lowcore.words.address)
 438                         offset = offset*2 + 4;
 439                 else
 440                         offset = offset*2;
 441                 tmp = *(__u32 *)((addr_t) &child->thread.per_info + offset);
 442
 443         } else
 444                 tmp = 0;
 445
 446         return put_user(tmp, (__u32 __user *) data);
 447 }
 448
 449 /*
 450  * Same as poke_user but for a 31 bit program.
 451  */
 452 static int
 453 poke_user_emu31(struct task_struct *child, addr_t addr, addr_t data)
 454 {
 455         struct user32 *dummy32 = NULL;
 456         per_struct32 *dummy_per32 = NULL;
 457         addr_t offset;
 458         __u32 tmp;
 459
 460         if (!test_thread_flag(TIF_31BIT) ||
 461             (addr & 3) || addr > sizeof(struct user32) - 3)
 462                 return -EIO;
 463
 464         tmp = (__u32) data;
 465
 466         if (addr < (addr_t) &dummy32->regs.acrs) {
 467                 /*
 468                  * psw, gprs, acrs and orig_gpr2 are stored on the stack
 469                  */
 470                 if (addr == (addr_t) &dummy32->regs.psw.mask) {
 471                         /* Build a 64 bit psw mask from 31 bit mask. */
 472                         if (tmp != PSW32_MASK_MERGE(PSW32_USER_BITS, tmp))
 473                                 /* Invalid psw mask. */
 474                                 return -EINVAL;
 475                         __KSTK_PTREGS(child)->psw.mask =
 476                                 PSW_MASK_MERGE(PSW_USER32_BITS, (__u64) tmp << 32);
 477                 } else if (addr == (addr_t) &dummy32->regs.psw.addr) {
 478                         /* Build a 64 bit psw address from 31 bit address. */
 479                         __KSTK_PTREGS(child)->psw.addr =
 480                                 (__u64) tmp & PSW32_ADDR_INSN;
 481                 } else {
 482                         /* gpr 0-15 */
 483                         *(__u32*)((addr_t) &__KSTK_PTREGS(child)->psw
 484                                   + addr*2 + 4) = tmp;
 485                 }
 486         } else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
 487                 /*
 488                  * access registers are stored in the thread structure
 489                  */
 490                 offset = addr - (addr_t) &dummy32->regs.acrs;
 491                 *(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;
 492
 493         } else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
 494                 /*
 495                  * orig_gpr2 is stored on the kernel stack
 496                  */
 497                 *(__u32*)((addr_t) &__KSTK_PTREGS(child)->orig_gpr2 + 4) = tmp;
 498
 499         } else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
 500                 /*
 501                  * floating point regs. are stored in the thread structure
 502                  */
 503                 if (addr == (addr_t) &dummy32->regs.fp_regs.fpc &&
 504                     (tmp & ~FPC_VALID_MASK) != 0)
 505                         /* Invalid floating point control. */
 506                         return -EINVAL;
 507                 offset = addr - (addr_t) &dummy32->regs.fp_regs;
 508                 *(__u32 *)((addr_t) &child->thread.fp_regs + offset) = tmp;
 509
 510         } else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
 511                 /*
 512                  * per_info is found in the thread structure.
 513                  */
 514                 offset = addr - (addr_t) &dummy32->regs.per_info;
 515                 /*
 516                  * This is magic. See per_struct and per_struct32.
 517                  * By incident the offsets in per_struct are exactly
 518                  * twice the offsets in per_struct32 for all fields.
 519                  * The 8 byte fields need special handling though,
 520                  * because the second half (bytes 4-7) is needed and
 521                  * not the first half.
 522                  */
 523                 if ((offset >= (addr_t) &dummy_per32->control_regs &&
 524                      offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
 525                     (offset >= (addr_t) &dummy_per32->starting_addr &&
 526                      offset <= (addr_t) &dummy_per32->ending_addr) ||
 527                     offset == (addr_t) &dummy_per32->lowcore.words.address)
 528                         offset = offset*2 + 4;
 529                 else
 530                         offset = offset*2;
 531                 *(__u32 *)((addr_t) &child->thread.per_info + offset) = tmp;
 532
 533         }
 534
 535         FixPerRegisters(child);
 536         return 0;
 537 }
 538
 539 static int
 540 do_ptrace_emu31(struct task_struct *child, long request, long addr, long data)
 541 {
 542         unsigned int tmp;  /* 4 bytes !! */
 543         ptrace_area_emu31 parea;
 544         int copied, ret;
 545
 546         switch (request) {
 547         case PTRACE_PEEKTEXT:
 548         case PTRACE_PEEKDATA:
 549                 /* read word at location addr. */
 550                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 551                 if (copied != sizeof(tmp))
 552                         return -EIO;
 553                 return put_user(tmp, (unsigned int __user *) data);
 554
 555         case PTRACE_PEEKUSR:
 556                 /* read the word at location addr in the USER area. */
 557                 return peek_user_emu31(child, addr, data);
 558
 559         case PTRACE_POKETEXT:
 560         case PTRACE_POKEDATA:
 561                 /* write the word at location addr. */
 562                 tmp = data;
 563                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 1);
 564                 if (copied != sizeof(tmp))
 565                         return -EIO;
 566                 return 0;
 567
 568         case PTRACE_POKEUSR:
 569                 /* write the word at location addr in the USER area */
 570                 return poke_user_emu31(child, addr, data);
 571
 572         case PTRACE_PEEKUSR_AREA:
 573         case PTRACE_POKEUSR_AREA:
 574                 if (copy_from_user(&parea, (void __user *) addr,
 575                                                         sizeof(parea)))
 576                         return -EFAULT;
 577                 addr = parea.kernel_addr;
 578                 data = parea.process_addr;
 579                 copied = 0;
 580                 while (copied < parea.len) {
 581                         if (request == PTRACE_PEEKUSR_AREA)
 582                                 ret = peek_user_emu31(child, addr, data);
 583                         else {
 584                                 __u32 tmp;
 585                                 if (get_user (tmp, (__u32 __user *) data))
 586                                         return -EFAULT;
 587                                 ret = poke_user_emu31(child, addr, tmp);
 588                         }
 589                         if (ret)
 590                                 return ret;
 591                         addr += sizeof(unsigned int);
 592                         data += sizeof(unsigned int);
 593                         copied += sizeof(unsigned int);
 594                 }
 595                 return 0;
 596         case PTRACE_GETEVENTMSG:
 597                 return put_user((__u32) child->ptrace_message,
 598                                 (unsigned int __user *) data);
 599         case PTRACE_GETSIGINFO:
 600                 if (child->last_siginfo == NULL)
 601                         return -EINVAL;
 602                 return copy_siginfo_to_user32((compat_siginfo_t __user *) data,
 603                                               child->last_siginfo);
 604         case PTRACE_SETSIGINFO:
 605                 if (child->last_siginfo == NULL)
 606                         return -EINVAL;
 607                 return copy_siginfo_from_user32(child->last_siginfo,
 608                                                 (compat_siginfo_t __user *) data);
 609         }
 610         return ptrace_request(child, request, addr, data);
 611 }
 612 #endif
 613
 614 #define PT32_IEEE_IP 0x13c
 615
 616 static int
 617 do_ptrace(struct task_struct *child, long request, long addr, long data)
 618 {
 619         int ret;
 620
 621         if (request == PTRACE_ATTACH)
 622                 return ptrace_attach(child);
 623
 624         /*
 625          * Special cases to get/store the ieee instructions pointer.
 626          */
 627         if (child == current) {
 628                 if (request == PTRACE_PEEKUSR && addr == PT_IEEE_IP)
 629                         return peek_user(child, addr, data);
 630                 if (request == PTRACE_POKEUSR && addr == PT_IEEE_IP)
 631                         return poke_user(child, addr, data);
 632 #ifdef CONFIG_S390_SUPPORT
 633                 if (request == PTRACE_PEEKUSR &&
 634                     addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
 635                         return peek_user_emu31(child, addr, data);
 636                 if (request == PTRACE_POKEUSR &&
 637                     addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
 638                         return poke_user_emu31(child, addr, data);
 639 #endif
 640         }
 641
 642         ret = ptrace_check_attach(child, request == PTRACE_KILL);
 643         if (ret < 0)
 644                 return ret;
 645
 646         switch (request) {
 647         case PTRACE_SYSCALL:
 648                 /* continue and stop at next (return from) syscall */
 649         case PTRACE_CONT:
 650                 /* restart after signal. */
 651                 if (!valid_signal(data))
 652                         return -EIO;
 653                 if (request == PTRACE_SYSCALL)
 654                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 655                 else
 656                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 657                 child->exit_code = data;
 658                 /* make sure the single step bit is not set. */
 659                 clear_single_step(child);
 660                 wake_up_process(child);
 661                 return 0;
 662
 663         case PTRACE_KILL:
 664                 /*
 665                  * make the child exit.  Best I can do is send it a sigkill.
 666                  * perhaps it should be put in the status that it wants to
 667                  * exit.
 668                  */
 669                 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
 670                         return 0;
 671                 child->exit_code = SIGKILL;
 672                 /* make sure the single step bit is not set. */
 673                 clear_single_step(child);
 674                 wake_up_process(child);
 675                 return 0;
 676
 677         case PTRACE_SINGLESTEP:
 678                 /* set the trap flag. */
 679                 if (!valid_signal(data))
 680                         return -EIO;
 681                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 682                 child->exit_code = data;
 683                 if (data)
 684                         set_tsk_thread_flag(child, TIF_SINGLE_STEP);
 685                 else
 686                         set_single_step(child);
 687                 /* give it a chance to run. */
 688                 wake_up_process(child);
 689                 return 0;
 690
 691         case PTRACE_DETACH:
 692                 /* detach a process that was attached. */
 693                 return ptrace_detach(child, data);
 694
 695
 696         /* Do requests that differ for 31/64 bit */
 697         default:
 698 #ifdef CONFIG_S390_SUPPORT
 699                 if (test_thread_flag(TIF_31BIT))
 700                         return do_ptrace_emu31(child, request, addr, data);
 701 #endif
 702                 return do_ptrace_normal(child, request, addr, data);
 703         }
 704         /* Not reached.  */
 705         return -EIO;
 706 }
 707
 708 asmlinkage long
 709 sys_ptrace(long request, long pid, long addr, long data)
 710 {
 711         struct task_struct *child;
 712         int ret;
 713
 714         lock_kernel();
 715
 716         if (request == PTRACE_TRACEME) {
 717                 /* are we already being traced? */
 718                 ret = -EPERM;
 719                 if (current->ptrace & PT_PTRACED)
 720                         goto out;
 721                 ret = security_ptrace(current->parent, current);
 722                 if (ret)
 723                         goto out;
 724                 /* set the ptrace bit in the process flags. */
 725                 current->ptrace |= PT_PTRACED;
 726                 goto out;
 727         }
 728
 729         ret = -EPERM;
 730         if (pid == 1)           /* you may not mess with init */
 731                 goto out;
 732
 733         ret = -ESRCH;
 734         read_lock(&tasklist_lock);
 735         child = find_task_by_pid(pid);
 736         if (child)
 737                 get_task_struct(child);
 738         read_unlock(&tasklist_lock);
 739         if (!child)
 740                 goto out;
 741
 742         ret = do_ptrace(child, request, addr, data);
 743
 744         put_task_struct(child);
 745 out:
 746         unlock_kernel();
 747         return ret;
 748 }
 749
 750 asmlinkage void
 751 syscall_trace(struct pt_regs *regs, int entryexit)
 752 {
 753         if (unlikely(current->audit_context) && entryexit)
 754                 audit_syscall_exit(current, AUDITSC_RESULT(regs->gprs[2]), regs->gprs[2]);
 755
 756         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 757                 goto out;
 758         if (!(current->ptrace & PT_PTRACED))
 759                 goto out;
 760         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 761                                  ? 0x80 : 0));
 762
 763         /*
 764          * If the debuffer has set an invalid system call number,
 765          * we prepare to skip the system call restart handling.
 766          */
 767         if (!entryexit && regs->gprs[2] >= NR_syscalls)
 768                 regs->trap = -1;
 769
 770         /*
 771          * this isn't the same as continuing with a signal, but it will do
 772          * for normal use.  strace only continues with a signal if the
 773          * stopping signal is not SIGTRAP.  -brl
 774          */
 775         if (current->exit_code) {
 776                 send_sig(current->exit_code, current, 1);
 777                 current->exit_code = 0;
 778         }
 779  out:
 780         if (unlikely(current->audit_context) && !entryexit)
 781                 audit_syscall_entry(current,
 782                                     test_thread_flag(TIF_31BIT)?AUDIT_ARCH_S390:AUDIT_ARCH_S390X,
 783                                     regs->gprs[2], regs->orig_gpr2, regs->gprs[3],
 784                                     regs->gprs[4], regs->gprs[5]);
 785 }