arch/s390/kernel/ptrace.c

   1 /*
   2  *  Ptrace user space interface.
   3  *
   4  *    Copyright IBM Corp. 1999, 2010
   5  *    Author(s): Denis Joseph Barrow
   6  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/sched.h>
  11 #include <linux/mm.h>
  12 #include <linux/smp.h>
  13 #include <linux/errno.h>
  14 #include <linux/ptrace.h>
  15 #include <linux/user.h>
  16 #include <linux/security.h>
  17 #include <linux/audit.h>
  18 #include <linux/signal.h>
  19 #include <linux/elf.h>
  20 #include <linux/regset.h>
  21 #include <linux/tracehook.h>
  22 #include <linux/seccomp.h>
  23 #include <linux/compat.h>
  24 #include <trace/syscall.h>
  25 #include <asm/segment.h>
  26 #include <asm/page.h>
  27 #include <asm/pgtable.h>
  28 #include <asm/pgalloc.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/unistd.h>
  31 #include <asm/switch_to.h>
  32 #include "entry.h"
  33
  34 #ifdef CONFIG_COMPAT
  35 #include "compat_ptrace.h"
  36 #endif
  37
  38 #define CREATE_TRACE_POINTS
  39 #include <trace/events/syscalls.h>
  40
  41 enum s390_regset {
  42         REGSET_GENERAL,
  43         REGSET_FP,
  44         REGSET_LAST_BREAK,
  45         REGSET_TDB,
  46         REGSET_SYSTEM_CALL,
  47         REGSET_GENERAL_EXTENDED,
  48 };
  49
  50 void update_per_regs(struct task_struct *task)
  51 {
  52         struct pt_regs *regs = task_pt_regs(task);
  53         struct thread_struct *thread = &task->thread;
  54         struct per_regs old, new;
  55
  56 #ifdef CONFIG_64BIT
  57         /* Take care of the enable/disable of transactional execution. */
  58         if (MACHINE_HAS_TE) {
  59                 unsigned long cr0, cr0_new;
  60
  61                 __ctl_store(cr0, 0, 0);
  62                 /* set or clear transaction execution bits 8 and 9. */
  63                 if (task->thread.per_flags & PER_FLAG_NO_TE)
  64                         cr0_new = cr0 & ~(3UL << 54);
  65                 else
  66                         cr0_new = cr0 | (3UL << 54);
  67                 /* Only load control register 0 if necessary. */
  68                 if (cr0 != cr0_new)
  69                         __ctl_load(cr0_new, 0, 0);
  70         }
  71 #endif
  72         /* Copy user specified PER registers */
  73         new.control = thread->per_user.control;
  74         new.start = thread->per_user.start;
  75         new.end = thread->per_user.end;
  76
  77         /* merge TIF_SINGLE_STEP into user specified PER registers. */
  78         if (test_tsk_thread_flag(task, TIF_SINGLE_STEP)) {
  79                 new.control |= PER_EVENT_IFETCH;
  80 #ifdef CONFIG_64BIT
  81                 new.control |= PER_CONTROL_SUSPENSION;
  82                 new.control |= PER_EVENT_TRANSACTION_END;
  83 #endif
  84                 new.start = 0;
  85                 new.end = PSW_ADDR_INSN;
  86         }
  87
  88         /* Take care of the PER enablement bit in the PSW. */
  89         if (!(new.control & PER_EVENT_MASK)) {
  90                 regs->psw.mask &= ~PSW_MASK_PER;
  91                 return;
  92         }
  93         regs->psw.mask |= PSW_MASK_PER;
  94         __ctl_store(old, 9, 11);
  95         if (memcmp(&new, &old, sizeof(struct per_regs)) != 0)
  96                 __ctl_load(new, 9, 11);
  97 }
  98
  99 void user_enable_single_step(struct task_struct *task)
 100 {
 101         set_tsk_thread_flag(task, TIF_SINGLE_STEP);
 102         if (task == current)
 103                 update_per_regs(task);
 104 }
 105
 106 void user_disable_single_step(struct task_struct *task)
 107 {
 108         clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
 109         if (task == current)
 110                 update_per_regs(task);
 111 }
 112
 113 /*
 114  * Called by kernel/ptrace.c when detaching..
 115  *
 116  * Clear all debugging related fields.
 117  */
 118 void ptrace_disable(struct task_struct *task)
 119 {
 120         memset(&task->thread.per_user, 0, sizeof(task->thread.per_user));
 121         memset(&task->thread.per_event, 0, sizeof(task->thread.per_event));
 122         clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
 123         clear_tsk_thread_flag(task, TIF_PER_TRAP);
 124         task->thread.per_flags = 0;
 125 }
 126
 127 #ifndef CONFIG_64BIT
 128 # define __ADDR_MASK 3
 129 #else
 130 # define __ADDR_MASK 7
 131 #endif
 132
 133 static inline unsigned long __peek_user_per(struct task_struct *child,
 134                                             addr_t addr)
 135 {
 136         struct per_struct_kernel *dummy = NULL;
 137
 138         if (addr == (addr_t) &dummy->cr9)
 139                 /* Control bits of the active per set. */
 140                 return test_thread_flag(TIF_SINGLE_STEP) ?
 141                         PER_EVENT_IFETCH : child->thread.per_user.control;
 142         else if (addr == (addr_t) &dummy->cr10)
 143                 /* Start address of the active per set. */
 144                 return test_thread_flag(TIF_SINGLE_STEP) ?
 145                         0 : child->thread.per_user.start;
 146         else if (addr == (addr_t) &dummy->cr11)
 147                 /* End address of the active per set. */
 148                 return test_thread_flag(TIF_SINGLE_STEP) ?
 149                         PSW_ADDR_INSN : child->thread.per_user.end;
 150         else if (addr == (addr_t) &dummy->bits)
 151                 /* Single-step bit. */
 152                 return test_thread_flag(TIF_SINGLE_STEP) ?
 153                         (1UL << (BITS_PER_LONG - 1)) : 0;
 154         else if (addr == (addr_t) &dummy->starting_addr)
 155                 /* Start address of the user specified per set. */
 156                 return child->thread.per_user.start;
 157         else if (addr == (addr_t) &dummy->ending_addr)
 158                 /* End address of the user specified per set. */
 159                 return child->thread.per_user.end;
 160         else if (addr == (addr_t) &dummy->perc_atmid)
 161                 /* PER code, ATMID and AI of the last PER trap */
 162                 return (unsigned long)
 163                         child->thread.per_event.cause << (BITS_PER_LONG - 16);
 164         else if (addr == (addr_t) &dummy->address)
 165                 /* Address of the last PER trap */
 166                 return child->thread.per_event.address;
 167         else if (addr == (addr_t) &dummy->access_id)
 168                 /* Access id of the last PER trap */
 169                 return (unsigned long)
 170                         child->thread.per_event.paid << (BITS_PER_LONG - 8);
 171         return 0;
 172 }
 173
 174 /*
 175  * Read the word at offset addr from the user area of a process. The
 176  * trouble here is that the information is littered over different
 177  * locations. The process registers are found on the kernel stack,
 178  * the floating point stuff and the trace settings are stored in
 179  * the task structure. In addition the different structures in
 180  * struct user contain pad bytes that should be read as zeroes.
 181  * Lovely...
 182  */
 183 static unsigned long __peek_user(struct task_struct *child, addr_t addr)
 184 {
 185         struct user *dummy = NULL;
 186         addr_t offset, tmp;
 187
 188         if (addr < (addr_t) &dummy->regs.acrs) {
 189                 /*
 190                  * psw and gprs are stored on the stack
 191                  */
 192                 tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
 193                 if (addr == (addr_t) &dummy->regs.psw.mask)
 194                         /* Return a clean psw mask. */
 195                         tmp = psw_user_bits | (tmp & PSW_MASK_USER);
 196
 197         } else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
 198                 /*
 199                  * access registers are stored in the thread structure
 200                  */
 201                 offset = addr - (addr_t) &dummy->regs.acrs;
 202 #ifdef CONFIG_64BIT
 203                 /*
 204                  * Very special case: old & broken 64 bit gdb reading
 205                  * from acrs[15]. Result is a 64 bit value. Read the
 206                  * 32 bit acrs[15] value and shift it by 32. Sick...
 207                  */
 208                 if (addr == (addr_t) &dummy->regs.acrs[15])
 209                         tmp = ((unsigned long) child->thread.acrs[15]) << 32;
 210                 else
 211 #endif
 212                 tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);
 213
 214         } else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
 215                 /*
 216                  * orig_gpr2 is stored on the kernel stack
 217                  */
 218                 tmp = (addr_t) task_pt_regs(child)->orig_gpr2;
 219
 220         } else if (addr < (addr_t) &dummy->regs.fp_regs) {
 221                 /*
 222                  * prevent reads of padding hole between
 223                  * orig_gpr2 and fp_regs on s390.
 224                  */
 225                 tmp = 0;
 226
 227         } else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
 228                 /*
 229                  * floating point regs. are stored in the thread structure
 230                  */
 231                 offset = addr - (addr_t) &dummy->regs.fp_regs;
 232                 tmp = *(addr_t *)((addr_t) &child->thread.fp_regs + offset);
 233                 if (addr == (addr_t) &dummy->regs.fp_regs.fpc)
 234                         tmp &= (unsigned long) FPC_VALID_MASK
 235                                 << (BITS_PER_LONG - 32);
 236
 237         } else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
 238                 /*
 239                  * Handle access to the per_info structure.
 240                  */
 241                 addr -= (addr_t) &dummy->regs.per_info;
 242                 tmp = __peek_user_per(child, addr);
 243
 244         } else
 245                 tmp = 0;
 246
 247         return tmp;
 248 }
 249
 250 static int
 251 peek_user(struct task_struct *child, addr_t addr, addr_t data)
 252 {
 253         addr_t tmp, mask;
 254
 255         /*
 256          * Stupid gdb peeks/pokes the access registers in 64 bit with
 257          * an alignment of 4. Programmers from hell...
 258          */
 259         mask = __ADDR_MASK;
 260 #ifdef CONFIG_64BIT
 261         if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs &&
 262             addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
 263                 mask = 3;
 264 #endif
 265         if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
 266                 return -EIO;
 267
 268         tmp = __peek_user(child, addr);
 269         return put_user(tmp, (addr_t __user *) data);
 270 }
 271
 272 static inline void __poke_user_per(struct task_struct *child,
 273                                    addr_t addr, addr_t data)
 274 {
 275         struct per_struct_kernel *dummy = NULL;
 276
 277         /*
 278          * There are only three fields in the per_info struct that the
 279          * debugger user can write to.
 280          * 1) cr9: the debugger wants to set a new PER event mask
 281          * 2) starting_addr: the debugger wants to set a new starting
 282          *    address to use with the PER event mask.
 283          * 3) ending_addr: the debugger wants to set a new ending
 284          *    address to use with the PER event mask.
 285          * The user specified PER event mask and the start and end
 286          * addresses are used only if single stepping is not in effect.
 287          * Writes to any other field in per_info are ignored.
 288          */
 289         if (addr == (addr_t) &dummy->cr9)
 290                 /* PER event mask of the user specified per set. */
 291                 child->thread.per_user.control =
 292                         data & (PER_EVENT_MASK | PER_CONTROL_MASK);
 293         else if (addr == (addr_t) &dummy->starting_addr)
 294                 /* Starting address of the user specified per set. */
 295                 child->thread.per_user.start = data;
 296         else if (addr == (addr_t) &dummy->ending_addr)
 297                 /* Ending address of the user specified per set. */
 298                 child->thread.per_user.end = data;
 299 }
 300
 301 /*
 302  * Write a word to the user area of a process at location addr. This
 303  * operation does have an additional problem compared to peek_user.
 304  * Stores to the program status word and on the floating point
 305  * control register needs to get checked for validity.
 306  */
 307 static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
 308 {
 309         struct user *dummy = NULL;
 310         addr_t offset;
 311
 312         if (addr < (addr_t) &dummy->regs.acrs) {
 313                 /*
 314                  * psw and gprs are stored on the stack
 315                  */
 316                 if (addr == (addr_t) &dummy->regs.psw.mask &&
 317                     ((data & ~PSW_MASK_USER) != psw_user_bits ||
 318                      ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))))
 319                         /* Invalid psw mask. */
 320                         return -EINVAL;
 321                 *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr) = data;
 322
 323         } else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
 324                 /*
 325                  * access registers are stored in the thread structure
 326                  */
 327                 offset = addr - (addr_t) &dummy->regs.acrs;
 328 #ifdef CONFIG_64BIT
 329                 /*
 330                  * Very special case: old & broken 64 bit gdb writing
 331                  * to acrs[15] with a 64 bit value. Ignore the lower
 332                  * half of the value and write the upper 32 bit to
 333                  * acrs[15]. Sick...
 334                  */
 335                 if (addr == (addr_t) &dummy->regs.acrs[15])
 336                         child->thread.acrs[15] = (unsigned int) (data >> 32);
 337                 else
 338 #endif
 339                 *(addr_t *)((addr_t) &child->thread.acrs + offset) = data;
 340
 341         } else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
 342                 /*
 343                  * orig_gpr2 is stored on the kernel stack
 344                  */
 345                 task_pt_regs(child)->orig_gpr2 = data;
 346
 347         } else if (addr < (addr_t) &dummy->regs.fp_regs) {
 348                 /*
 349                  * prevent writes of padding hole between
 350                  * orig_gpr2 and fp_regs on s390.
 351                  */
 352                 return 0;
 353
 354         } else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
 355                 /*
 356                  * floating point regs. are stored in the thread structure
 357                  */
 358                 if (addr == (addr_t) &dummy->regs.fp_regs.fpc &&
 359                     (data & ~((unsigned long) FPC_VALID_MASK
 360                               << (BITS_PER_LONG - 32))) != 0)
 361                         return -EINVAL;
 362                 offset = addr - (addr_t) &dummy->regs.fp_regs;
 363                 *(addr_t *)((addr_t) &child->thread.fp_regs + offset) = data;
 364
 365         } else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
 366                 /*
 367                  * Handle access to the per_info structure.
 368                  */
 369                 addr -= (addr_t) &dummy->regs.per_info;
 370                 __poke_user_per(child, addr, data);
 371
 372         }
 373
 374         return 0;
 375 }
 376
 377 static int poke_user(struct task_struct *child, addr_t addr, addr_t data)
 378 {
 379         addr_t mask;
 380
 381         /*
 382          * Stupid gdb peeks/pokes the access registers in 64 bit with
 383          * an alignment of 4. Programmers from hell indeed...
 384          */
 385         mask = __ADDR_MASK;
 386 #ifdef CONFIG_64BIT
 387         if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs &&
 388             addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
 389                 mask = 3;
 390 #endif
 391         if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
 392                 return -EIO;
 393
 394         return __poke_user(child, addr, data);
 395 }
 396
 397 long arch_ptrace(struct task_struct *child, long request,
 398                  unsigned long addr, unsigned long data)
 399 {
 400         ptrace_area parea;
 401         int copied, ret;
 402
 403         switch (request) {
 404         case PTRACE_PEEKUSR:
 405                 /* read the word at location addr in the USER area. */
 406                 return peek_user(child, addr, data);
 407
 408         case PTRACE_POKEUSR:
 409                 /* write the word at location addr in the USER area */
 410                 return poke_user(child, addr, data);
 411
 412         case PTRACE_PEEKUSR_AREA:
 413         case PTRACE_POKEUSR_AREA:
 414                 if (copy_from_user(&parea, (void __force __user *) addr,
 415                                                         sizeof(parea)))
 416                         return -EFAULT;
 417                 addr = parea.kernel_addr;
 418                 data = parea.process_addr;
 419                 copied = 0;
 420                 while (copied < parea.len) {
 421                         if (request == PTRACE_PEEKUSR_AREA)
 422                                 ret = peek_user(child, addr, data);
 423                         else {
 424                                 addr_t utmp;
 425                                 if (get_user(utmp,
 426                                              (addr_t __force __user *) data))
 427                                         return -EFAULT;
 428                                 ret = poke_user(child, addr, utmp);
 429                         }
 430                         if (ret)
 431                                 return ret;
 432                         addr += sizeof(unsigned long);
 433                         data += sizeof(unsigned long);
 434                         copied += sizeof(unsigned long);
 435                 }
 436                 return 0;
 437         case PTRACE_GET_LAST_BREAK:
 438                 put_user(task_thread_info(child)->last_break,
 439                          (unsigned long __user *) data);
 440                 return 0;
 441         case PTRACE_ENABLE_TE:
 442                 if (!MACHINE_HAS_TE)
 443                         return -EIO;
 444                 child->thread.per_flags &= ~PER_FLAG_NO_TE;
 445                 return 0;
 446         case PTRACE_DISABLE_TE:
 447                 if (!MACHINE_HAS_TE)
 448                         return -EIO;
 449                 child->thread.per_flags |= PER_FLAG_NO_TE;
 450                 return 0;
 451         default:
 452                 /* Removing high order bit from addr (only for 31 bit). */
 453                 addr &= PSW_ADDR_INSN;
 454                 return ptrace_request(child, request, addr, data);
 455         }
 456 }
 457
 458 #ifdef CONFIG_COMPAT
 459 /*
 460  * Now the fun part starts... a 31 bit program running in the
 461  * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
 462  * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
 463  * to handle, the difference to the 64 bit versions of the requests
 464  * is that the access is done in multiples of 4 byte instead of
 465  * 8 bytes (sizeof(unsigned long) on 31/64 bit).
 466  * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
 467  * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
 468  * is a 31 bit program too, the content of struct user can be
 469  * emulated. A 31 bit program peeking into the struct user of
 470  * a 64 bit program is a no-no.
 471  */
 472
 473 /*
 474  * Same as peek_user_per but for a 31 bit program.
 475  */
 476 static inline __u32 __peek_user_per_compat(struct task_struct *child,
 477                                            addr_t addr)
 478 {
 479         struct compat_per_struct_kernel *dummy32 = NULL;
 480
 481         if (addr == (addr_t) &dummy32->cr9)
 482                 /* Control bits of the active per set. */
 483                 return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
 484                         PER_EVENT_IFETCH : child->thread.per_user.control;
 485         else if (addr == (addr_t) &dummy32->cr10)
 486                 /* Start address of the active per set. */
 487                 return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
 488                         0 : child->thread.per_user.start;
 489         else if (addr == (addr_t) &dummy32->cr11)
 490                 /* End address of the active per set. */
 491                 return test_thread_flag(TIF_SINGLE_STEP) ?
 492                         PSW32_ADDR_INSN : child->thread.per_user.end;
 493         else if (addr == (addr_t) &dummy32->bits)
 494                 /* Single-step bit. */
 495                 return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
 496                         0x80000000 : 0;
 497         else if (addr == (addr_t) &dummy32->starting_addr)
 498                 /* Start address of the user specified per set. */
 499                 return (__u32) child->thread.per_user.start;
 500         else if (addr == (addr_t) &dummy32->ending_addr)
 501                 /* End address of the user specified per set. */
 502                 return (__u32) child->thread.per_user.end;
 503         else if (addr == (addr_t) &dummy32->perc_atmid)
 504                 /* PER code, ATMID and AI of the last PER trap */
 505                 return (__u32) child->thread.per_event.cause << 16;
 506         else if (addr == (addr_t) &dummy32->address)
 507                 /* Address of the last PER trap */
 508                 return (__u32) child->thread.per_event.address;
 509         else if (addr == (addr_t) &dummy32->access_id)
 510                 /* Access id of the last PER trap */
 511                 return (__u32) child->thread.per_event.paid << 24;
 512         return 0;
 513 }
 514
 515 /*
 516  * Same as peek_user but for a 31 bit program.
 517  */
 518 static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
 519 {
 520         struct compat_user *dummy32 = NULL;
 521         addr_t offset;
 522         __u32 tmp;
 523
 524         if (addr < (addr_t) &dummy32->regs.acrs) {
 525                 struct pt_regs *regs = task_pt_regs(child);
 526                 /*
 527                  * psw and gprs are stored on the stack
 528                  */
 529                 if (addr == (addr_t) &dummy32->regs.psw.mask) {
 530                         /* Fake a 31 bit psw mask. */
 531                         tmp = (__u32)(regs->psw.mask >> 32);
 532                         tmp = psw32_user_bits | (tmp & PSW32_MASK_USER);
 533                 } else if (addr == (addr_t) &dummy32->regs.psw.addr) {
 534                         /* Fake a 31 bit psw address. */
 535                         tmp = (__u32) regs->psw.addr |
 536                                 (__u32)(regs->psw.mask & PSW_MASK_BA);
 537                 } else {
 538                         /* gpr 0-15 */
 539                         tmp = *(__u32 *)((addr_t) &regs->psw + addr*2 + 4);
 540                 }
 541         } else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
 542                 /*
 543                  * access registers are stored in the thread structure
 544                  */
 545                 offset = addr - (addr_t) &dummy32->regs.acrs;
 546                 tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);
 547
 548         } else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
 549                 /*
 550                  * orig_gpr2 is stored on the kernel stack
 551                  */
 552                 tmp = *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4);
 553
 554         } else if (addr < (addr_t) &dummy32->regs.fp_regs) {
 555                 /*
 556                  * prevent reads of padding hole between
 557                  * orig_gpr2 and fp_regs on s390.
 558                  */
 559                 tmp = 0;
 560
 561         } else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
 562                 /*
 563                  * floating point regs. are stored in the thread structure
 564                  */
 565                 offset = addr - (addr_t) &dummy32->regs.fp_regs;
 566                 tmp = *(__u32 *)((addr_t) &child->thread.fp_regs + offset);
 567
 568         } else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
 569                 /*
 570                  * Handle access to the per_info structure.
 571                  */
 572                 addr -= (addr_t) &dummy32->regs.per_info;
 573                 tmp = __peek_user_per_compat(child, addr);
 574
 575         } else
 576                 tmp = 0;
 577
 578         return tmp;
 579 }
 580
 581 static int peek_user_compat(struct task_struct *child,
 582                             addr_t addr, addr_t data)
 583 {
 584         __u32 tmp;
 585
 586         if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user) - 3)
 587                 return -EIO;
 588
 589         tmp = __peek_user_compat(child, addr);
 590         return put_user(tmp, (__u32 __user *) data);
 591 }
 592
 593 /*
 594  * Same as poke_user_per but for a 31 bit program.
 595  */
 596 static inline void __poke_user_per_compat(struct task_struct *child,
 597                                           addr_t addr, __u32 data)
 598 {
 599         struct compat_per_struct_kernel *dummy32 = NULL;
 600
 601         if (addr == (addr_t) &dummy32->cr9)
 602                 /* PER event mask of the user specified per set. */
 603                 child->thread.per_user.control =
 604                         data & (PER_EVENT_MASK | PER_CONTROL_MASK);
 605         else if (addr == (addr_t) &dummy32->starting_addr)
 606                 /* Starting address of the user specified per set. */
 607                 child->thread.per_user.start = data;
 608         else if (addr == (addr_t) &dummy32->ending_addr)
 609                 /* Ending address of the user specified per set. */
 610                 child->thread.per_user.end = data;
 611 }
 612
 613 /*
 614  * Same as poke_user but for a 31 bit program.
 615  */
 616 static int __poke_user_compat(struct task_struct *child,
 617                               addr_t addr, addr_t data)
 618 {
 619         struct compat_user *dummy32 = NULL;
 620         __u32 tmp = (__u32) data;
 621         addr_t offset;
 622
 623         if (addr < (addr_t) &dummy32->regs.acrs) {
 624                 struct pt_regs *regs = task_pt_regs(child);
 625                 /*
 626                  * psw, gprs, acrs and orig_gpr2 are stored on the stack
 627                  */
 628                 if (addr == (addr_t) &dummy32->regs.psw.mask) {
 629                         /* Build a 64 bit psw mask from 31 bit mask. */
 630                         if ((tmp & ~PSW32_MASK_USER) != psw32_user_bits)
 631                                 /* Invalid psw mask. */
 632                                 return -EINVAL;
 633                         regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
 634                                 (regs->psw.mask & PSW_MASK_BA) |
 635                                 (__u64)(tmp & PSW32_MASK_USER) << 32;
 636                 } else if (addr == (addr_t) &dummy32->regs.psw.addr) {
 637                         /* Build a 64 bit psw address from 31 bit address. */
 638                         regs->psw.addr = (__u64) tmp & PSW32_ADDR_INSN;
 639                         /* Transfer 31 bit amode bit to psw mask. */
 640                         regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) |
 641                                 (__u64)(tmp & PSW32_ADDR_AMODE);
 642                 } else {
 643                         /* gpr 0-15 */
 644                         *(__u32*)((addr_t) &regs->psw + addr*2 + 4) = tmp;
 645                 }
 646         } else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
 647                 /*
 648                  * access registers are stored in the thread structure
 649                  */
 650                 offset = addr - (addr_t) &dummy32->regs.acrs;
 651                 *(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;
 652
 653         } else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
 654                 /*
 655                  * orig_gpr2 is stored on the kernel stack
 656                  */
 657                 *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4) = tmp;
 658
 659         } else if (addr < (addr_t) &dummy32->regs.fp_regs) {
 660                 /*
 661                  * prevent writess of padding hole between
 662                  * orig_gpr2 and fp_regs on s390.
 663                  */
 664                 return 0;
 665
 666         } else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
 667                 /*
 668                  * floating point regs. are stored in the thread structure
 669                  */
 670                 if (addr == (addr_t) &dummy32->regs.fp_regs.fpc &&
 671                     (tmp & ~FPC_VALID_MASK) != 0)
 672                         /* Invalid floating point control. */
 673                         return -EINVAL;
 674                 offset = addr - (addr_t) &dummy32->regs.fp_regs;
 675                 *(__u32 *)((addr_t) &child->thread.fp_regs + offset) = tmp;
 676
 677         } else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
 678                 /*
 679                  * Handle access to the per_info structure.
 680                  */
 681                 addr -= (addr_t) &dummy32->regs.per_info;
 682                 __poke_user_per_compat(child, addr, data);
 683         }
 684
 685         return 0;
 686 }
 687
 688 static int poke_user_compat(struct task_struct *child,
 689                             addr_t addr, addr_t data)
 690 {
 691         if (!is_compat_task() || (addr & 3) ||
 692             addr > sizeof(struct compat_user) - 3)
 693                 return -EIO;
 694
 695         return __poke_user_compat(child, addr, data);
 696 }
 697
 698 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 699                         compat_ulong_t caddr, compat_ulong_t cdata)
 700 {
 701         unsigned long addr = caddr;
 702         unsigned long data = cdata;
 703         compat_ptrace_area parea;
 704         int copied, ret;
 705
 706         switch (request) {
 707         case PTRACE_PEEKUSR:
 708                 /* read the word at location addr in the USER area. */
 709                 return peek_user_compat(child, addr, data);
 710
 711         case PTRACE_POKEUSR:
 712                 /* write the word at location addr in the USER area */
 713                 return poke_user_compat(child, addr, data);
 714
 715         case PTRACE_PEEKUSR_AREA:
 716         case PTRACE_POKEUSR_AREA:
 717                 if (copy_from_user(&parea, (void __force __user *) addr,
 718                                                         sizeof(parea)))
 719                         return -EFAULT;
 720                 addr = parea.kernel_addr;
 721                 data = parea.process_addr;
 722                 copied = 0;
 723                 while (copied < parea.len) {
 724                         if (request == PTRACE_PEEKUSR_AREA)
 725                                 ret = peek_user_compat(child, addr, data);
 726                         else {
 727                                 __u32 utmp;
 728                                 if (get_user(utmp,
 729                                              (__u32 __force __user *) data))
 730                                         return -EFAULT;
 731                                 ret = poke_user_compat(child, addr, utmp);
 732                         }
 733                         if (ret)
 734                                 return ret;
 735                         addr += sizeof(unsigned int);
 736                         data += sizeof(unsigned int);
 737                         copied += sizeof(unsigned int);
 738                 }
 739                 return 0;
 740         case PTRACE_GET_LAST_BREAK:
 741                 put_user(task_thread_info(child)->last_break,
 742                          (unsigned int __user *) data);
 743                 return 0;
 744         }
 745         return compat_ptrace_request(child, request, addr, data);
 746 }
 747 #endif
 748
 749 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
 750 {
 751         long ret = 0;
 752
 753         /* Do the secure computing check first. */
 754         if (secure_computing(regs->gprs[2])) {
 755                 /* seccomp failures shouldn't expose any additional code. */
 756                 ret = -1;
 757                 goto out;
 758         }
 759
 760         /*
 761          * The sysc_tracesys code in entry.S stored the system
 762          * call number to gprs[2].
 763          */
 764         if (test_thread_flag(TIF_SYSCALL_TRACE) &&
 765             (tracehook_report_syscall_entry(regs) ||
 766              regs->gprs[2] >= NR_syscalls)) {
 767                 /*
 768                  * Tracing decided this syscall should not happen or the
 769                  * debugger stored an invalid system call number. Skip
 770                  * the system call and the system call restart handling.
 771                  */
 772                 clear_thread_flag(TIF_SYSCALL);
 773                 ret = -1;
 774         }
 775
 776         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 777                 trace_sys_enter(regs, regs->gprs[2]);
 778
 779         audit_syscall_entry(is_compat_task() ?
 780                                 AUDIT_ARCH_S390 : AUDIT_ARCH_S390X,
 781                             regs->gprs[2], regs->orig_gpr2,
 782                             regs->gprs[3], regs->gprs[4],
 783                             regs->gprs[5]);
 784 out:
 785         return ret ?: regs->gprs[2];
 786 }
 787
 788 asmlinkage void do_syscall_trace_exit(struct pt_regs *regs)
 789 {
 790         audit_syscall_exit(regs);
 791
 792         if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 793                 trace_sys_exit(regs, regs->gprs[2]);
 794
 795         if (test_thread_flag(TIF_SYSCALL_TRACE))
 796                 tracehook_report_syscall_exit(regs, 0);
 797 }
 798
 799 /*
 800  * user_regset definitions.
 801  */
 802
 803 static int s390_regs_get(struct task_struct *target,
 804                          const struct user_regset *regset,
 805                          unsigned int pos, unsigned int count,
 806                          void *kbuf, void __user *ubuf)
 807 {
 808         if (target == current)
 809                 save_access_regs(target->thread.acrs);
 810
 811         if (kbuf) {
 812                 unsigned long *k = kbuf;
 813                 while (count > 0) {
 814                         *k++ = __peek_user(target, pos);
 815                         count -= sizeof(*k);
 816                         pos += sizeof(*k);
 817                 }
 818         } else {
 819                 unsigned long __user *u = ubuf;
 820                 while (count > 0) {
 821                         if (__put_user(__peek_user(target, pos), u++))
 822                                 return -EFAULT;
 823                         count -= sizeof(*u);
 824                         pos += sizeof(*u);
 825                 }
 826         }
 827         return 0;
 828 }
 829
 830 static int s390_regs_set(struct task_struct *target,
 831                          const struct user_regset *regset,
 832                          unsigned int pos, unsigned int count,
 833                          const void *kbuf, const void __user *ubuf)
 834 {
 835         int rc = 0;
 836
 837         if (target == current)
 838                 save_access_regs(target->thread.acrs);
 839
 840         if (kbuf) {
 841                 const unsigned long *k = kbuf;
 842                 while (count > 0 && !rc) {
 843                         rc = __poke_user(target, pos, *k++);
 844                         count -= sizeof(*k);
 845                         pos += sizeof(*k);
 846                 }
 847         } else {
 848                 const unsigned long  __user *u = ubuf;
 849                 while (count > 0 && !rc) {
 850                         unsigned long word;
 851                         rc = __get_user(word, u++);
 852                         if (rc)
 853                                 break;
 854                         rc = __poke_user(target, pos, word);
 855                         count -= sizeof(*u);
 856                         pos += sizeof(*u);
 857                 }
 858         }
 859
 860         if (rc == 0 && target == current)
 861                 restore_access_regs(target->thread.acrs);
 862
 863         return rc;
 864 }
 865
 866 static int s390_fpregs_get(struct task_struct *target,
 867                            const struct user_regset *regset, unsigned int pos,
 868                            unsigned int count, void *kbuf, void __user *ubuf)
 869 {
 870         if (target == current)
 871                 save_fp_regs(&target->thread.fp_regs);
 872
 873         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 874                                    &target->thread.fp_regs, 0, -1);
 875 }
 876
 877 static int s390_fpregs_set(struct task_struct *target,
 878                            const struct user_regset *regset, unsigned int pos,
 879                            unsigned int count, const void *kbuf,
 880                            const void __user *ubuf)
 881 {
 882         int rc = 0;
 883
 884         if (target == current)
 885                 save_fp_regs(&target->thread.fp_regs);
 886
 887         /* If setting FPC, must validate it first. */
 888         if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) {
 889                 u32 fpc[2] = { target->thread.fp_regs.fpc, 0 };
 890                 rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &fpc,
 891                                         0, offsetof(s390_fp_regs, fprs));
 892                 if (rc)
 893                         return rc;
 894                 if ((fpc[0] & ~FPC_VALID_MASK) != 0 || fpc[1] != 0)
 895                         return -EINVAL;
 896                 target->thread.fp_regs.fpc = fpc[0];
 897         }
 898
 899         if (rc == 0 && count > 0)
 900                 rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 901                                         target->thread.fp_regs.fprs,
 902                                         offsetof(s390_fp_regs, fprs), -1);
 903
 904         if (rc == 0 && target == current)
 905                 restore_fp_regs(&target->thread.fp_regs);
 906
 907         return rc;
 908 }
 909
 910 #ifdef CONFIG_64BIT
 911
 912 static int s390_last_break_get(struct task_struct *target,
 913                                const struct user_regset *regset,
 914                                unsigned int pos, unsigned int count,
 915                                void *kbuf, void __user *ubuf)
 916 {
 917         if (count > 0) {
 918                 if (kbuf) {
 919                         unsigned long *k = kbuf;
 920                         *k = task_thread_info(target)->last_break;
 921                 } else {
 922                         unsigned long  __user *u = ubuf;
 923                         if (__put_user(task_thread_info(target)->last_break, u))
 924                                 return -EFAULT;
 925                 }
 926         }
 927         return 0;
 928 }
 929
 930 static int s390_last_break_set(struct task_struct *target,
 931                                const struct user_regset *regset,
 932                                unsigned int pos, unsigned int count,
 933                                const void *kbuf, const void __user *ubuf)
 934 {
 935         return 0;
 936 }
 937
 938 static int s390_tdb_get(struct task_struct *target,
 939                         const struct user_regset *regset,
 940                         unsigned int pos, unsigned int count,
 941                         void *kbuf, void __user *ubuf)
 942 {
 943         struct pt_regs *regs = task_pt_regs(target);
 944         unsigned char *data;
 945
 946         if (!(regs->int_code & 0x200))
 947                 return -ENODATA;
 948         data = target->thread.trap_tdb;
 949         return user_regset_copyout(&pos, &count, &kbuf, &ubuf, data, 0, 256);
 950 }
 951
 952 static int s390_tdb_set(struct task_struct *target,
 953                         const struct user_regset *regset,
 954                         unsigned int pos, unsigned int count,
 955                         const void *kbuf, const void __user *ubuf)
 956 {
 957         return 0;
 958 }
 959
 960 #endif
 961
 962 static int s390_system_call_get(struct task_struct *target,
 963                                 const struct user_regset *regset,
 964                                 unsigned int pos, unsigned int count,
 965                                 void *kbuf, void __user *ubuf)
 966 {
 967         unsigned int *data = &task_thread_info(target)->system_call;
 968         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 969                                    data, 0, sizeof(unsigned int));
 970 }
 971
 972 static int s390_system_call_set(struct task_struct *target,
 973                                 const struct user_regset *regset,
 974                                 unsigned int pos, unsigned int count,
 975                                 const void *kbuf, const void __user *ubuf)
 976 {
 977         unsigned int *data = &task_thread_info(target)->system_call;
 978         return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 979                                   data, 0, sizeof(unsigned int));
 980 }
 981
 982 static const struct user_regset s390_regsets[] = {
 983         [REGSET_GENERAL] = {
 984                 .core_note_type = NT_PRSTATUS,
 985                 .n = sizeof(s390_regs) / sizeof(long),
 986                 .size = sizeof(long),
 987                 .align = sizeof(long),
 988                 .get = s390_regs_get,
 989                 .set = s390_regs_set,
 990         },
 991         [REGSET_FP] = {
 992                 .core_note_type = NT_PRFPREG,
 993                 .n = sizeof(s390_fp_regs) / sizeof(long),
 994                 .size = sizeof(long),
 995                 .align = sizeof(long),
 996                 .get = s390_fpregs_get,
 997                 .set = s390_fpregs_set,
 998         },
 999 #ifdef CONFIG_64BIT
1000         [REGSET_LAST_BREAK] = {
1001                 .core_note_type = NT_S390_LAST_BREAK,
1002                 .n = 1,
1003                 .size = sizeof(long),
1004                 .align = sizeof(long),
1005                 .get = s390_last_break_get,
1006                 .set = s390_last_break_set,
1007         },
1008         [REGSET_TDB] = {
1009                 .core_note_type = NT_S390_TDB,
1010                 .n = 1,
1011                 .size = 256,
1012                 .align = 1,
1013                 .get = s390_tdb_get,
1014                 .set = s390_tdb_set,
1015         },
1016 #endif
1017         [REGSET_SYSTEM_CALL] = {
1018                 .core_note_type = NT_S390_SYSTEM_CALL,
1019                 .n = 1,
1020                 .size = sizeof(unsigned int),
1021                 .align = sizeof(unsigned int),
1022                 .get = s390_system_call_get,
1023                 .set = s390_system_call_set,
1024         },
1025 };
1026
1027 static const struct user_regset_view user_s390_view = {
1028         .name = UTS_MACHINE,
1029         .e_machine = EM_S390,
1030         .regsets = s390_regsets,
1031         .n = ARRAY_SIZE(s390_regsets)
1032 };
1033
1034 #ifdef CONFIG_COMPAT
1035 static int s390_compat_regs_get(struct task_struct *target,
1036                                 const struct user_regset *regset,
1037                                 unsigned int pos, unsigned int count,
1038                                 void *kbuf, void __user *ubuf)
1039 {
1040         if (target == current)
1041                 save_access_regs(target->thread.acrs);
1042
1043         if (kbuf) {
1044                 compat_ulong_t *k = kbuf;
1045                 while (count > 0) {
1046                         *k++ = __peek_user_compat(target, pos);
1047                         count -= sizeof(*k);
1048                         pos += sizeof(*k);
1049                 }
1050         } else {
1051                 compat_ulong_t __user *u = ubuf;
1052                 while (count > 0) {
1053                         if (__put_user(__peek_user_compat(target, pos), u++))
1054                                 return -EFAULT;
1055                         count -= sizeof(*u);
1056                         pos += sizeof(*u);
1057                 }
1058         }
1059         return 0;
1060 }
1061
1062 static int s390_compat_regs_set(struct task_struct *target,
1063                                 const struct user_regset *regset,
1064                                 unsigned int pos, unsigned int count,
1065                                 const void *kbuf, const void __user *ubuf)
1066 {
1067         int rc = 0;
1068
1069         if (target == current)
1070                 save_access_regs(target->thread.acrs);
1071
1072         if (kbuf) {
1073                 const compat_ulong_t *k = kbuf;
1074                 while (count > 0 && !rc) {
1075                         rc = __poke_user_compat(target, pos, *k++);
1076                         count -= sizeof(*k);
1077                         pos += sizeof(*k);
1078                 }
1079         } else {
1080                 const compat_ulong_t  __user *u = ubuf;
1081                 while (count > 0 && !rc) {
1082                         compat_ulong_t word;
1083                         rc = __get_user(word, u++);
1084                         if (rc)
1085                                 break;
1086                         rc = __poke_user_compat(target, pos, word);
1087                         count -= sizeof(*u);
1088                         pos += sizeof(*u);
1089                 }
1090         }
1091
1092         if (rc == 0 && target == current)
1093                 restore_access_regs(target->thread.acrs);
1094
1095         return rc;
1096 }
1097
1098 static int s390_compat_regs_high_get(struct task_struct *target,
1099                                      const struct user_regset *regset,
1100                                      unsigned int pos, unsigned int count,
1101                                      void *kbuf, void __user *ubuf)
1102 {
1103         compat_ulong_t *gprs_high;
1104
1105         gprs_high = (compat_ulong_t *)
1106                 &task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
1107         if (kbuf) {
1108                 compat_ulong_t *k = kbuf;
1109                 while (count > 0) {
1110                         *k++ = *gprs_high;
1111                         gprs_high += 2;
1112                         count -= sizeof(*k);
1113                 }
1114         } else {
1115                 compat_ulong_t __user *u = ubuf;
1116                 while (count > 0) {
1117                         if (__put_user(*gprs_high, u++))
1118                                 return -EFAULT;
1119                         gprs_high += 2;
1120                         count -= sizeof(*u);
1121                 }
1122         }
1123         return 0;
1124 }
1125
1126 static int s390_compat_regs_high_set(struct task_struct *target,
1127                                      const struct user_regset *regset,
1128                                      unsigned int pos, unsigned int count,
1129                                      const void *kbuf, const void __user *ubuf)
1130 {
1131         compat_ulong_t *gprs_high;
1132         int rc = 0;
1133
1134         gprs_high = (compat_ulong_t *)
1135                 &task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
1136         if (kbuf) {
1137                 const compat_ulong_t *k = kbuf;
1138                 while (count > 0) {
1139                         *gprs_high = *k++;
1140                         *gprs_high += 2;
1141                         count -= sizeof(*k);
1142                 }
1143         } else {
1144                 const compat_ulong_t  __user *u = ubuf;
1145                 while (count > 0 && !rc) {
1146                         unsigned long word;
1147                         rc = __get_user(word, u++);
1148                         if (rc)
1149                                 break;
1150                         *gprs_high = word;
1151                         *gprs_high += 2;
1152                         count -= sizeof(*u);
1153                 }
1154         }
1155
1156         return rc;
1157 }
1158
1159 static int s390_compat_last_break_get(struct task_struct *target,
1160                                       const struct user_regset *regset,
1161                                       unsigned int pos, unsigned int count,
1162                                       void *kbuf, void __user *ubuf)
1163 {
1164         compat_ulong_t last_break;
1165
1166         if (count > 0) {
1167                 last_break = task_thread_info(target)->last_break;
1168                 if (kbuf) {
1169                         unsigned long *k = kbuf;
1170                         *k = last_break;
1171                 } else {
1172                         unsigned long  __user *u = ubuf;
1173                         if (__put_user(last_break, u))
1174                                 return -EFAULT;
1175                 }
1176         }
1177         return 0;
1178 }
1179
1180 static int s390_compat_last_break_set(struct task_struct *target,
1181                                       const struct user_regset *regset,
1182                                       unsigned int pos, unsigned int count,
1183                                       const void *kbuf, const void __user *ubuf)
1184 {
1185         return 0;
1186 }
1187
1188 static const struct user_regset s390_compat_regsets[] = {
1189         [REGSET_GENERAL] = {
1190                 .core_note_type = NT_PRSTATUS,
1191                 .n = sizeof(s390_compat_regs) / sizeof(compat_long_t),
1192                 .size = sizeof(compat_long_t),
1193                 .align = sizeof(compat_long_t),
1194                 .get = s390_compat_regs_get,
1195                 .set = s390_compat_regs_set,
1196         },
1197         [REGSET_FP] = {
1198                 .core_note_type = NT_PRFPREG,
1199                 .n = sizeof(s390_fp_regs) / sizeof(compat_long_t),
1200                 .size = sizeof(compat_long_t),
1201                 .align = sizeof(compat_long_t),
1202                 .get = s390_fpregs_get,
1203                 .set = s390_fpregs_set,
1204         },
1205         [REGSET_LAST_BREAK] = {
1206                 .core_note_type = NT_S390_LAST_BREAK,
1207                 .n = 1,
1208                 .size = sizeof(long),
1209                 .align = sizeof(long),
1210                 .get = s390_compat_last_break_get,
1211                 .set = s390_compat_last_break_set,
1212         },
1213         [REGSET_TDB] = {
1214                 .core_note_type = NT_S390_TDB,
1215                 .n = 1,
1216                 .size = 256,
1217                 .align = 1,
1218                 .get = s390_tdb_get,
1219                 .set = s390_tdb_set,
1220         },
1221         [REGSET_SYSTEM_CALL] = {
1222                 .core_note_type = NT_S390_SYSTEM_CALL,
1223                 .n = 1,
1224                 .size = sizeof(compat_uint_t),
1225                 .align = sizeof(compat_uint_t),
1226                 .get = s390_system_call_get,
1227                 .set = s390_system_call_set,
1228         },
1229         [REGSET_GENERAL_EXTENDED] = {
1230                 .core_note_type = NT_S390_HIGH_GPRS,
1231                 .n = sizeof(s390_compat_regs_high) / sizeof(compat_long_t),
1232                 .size = sizeof(compat_long_t),
1233                 .align = sizeof(compat_long_t),
1234                 .get = s390_compat_regs_high_get,
1235                 .set = s390_compat_regs_high_set,
1236         },
1237 };
1238
1239 static const struct user_regset_view user_s390_compat_view = {
1240         .name = "s390",
1241         .e_machine = EM_S390,
1242         .regsets = s390_compat_regsets,
1243         .n = ARRAY_SIZE(s390_compat_regsets)
1244 };
1245 #endif
1246
1247 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1248 {
1249 #ifdef CONFIG_COMPAT
1250         if (test_tsk_thread_flag(task, TIF_31BIT))
1251                 return &user_s390_compat_view;
1252 #endif
1253         return &user_s390_view;
1254 }
1255
1256 static const char *gpr_names[NUM_GPRS] = {
1257         "r0", "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
1258         "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
1259 };
1260
1261 unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset)
1262 {
1263         if (offset >= NUM_GPRS)
1264                 return 0;
1265         return regs->gprs[offset];
1266 }
1267
1268 int regs_query_register_offset(const char *name)
1269 {
1270         unsigned long offset;
1271
1272         if (!name || *name != 'r')
1273                 return -EINVAL;
1274         if (strict_strtoul(name + 1, 10, &offset))
1275                 return -EINVAL;
1276         if (offset >= NUM_GPRS)
1277                 return -EINVAL;
1278         return offset;
1279 }
1280
1281 const char *regs_query_register_name(unsigned int offset)
1282 {
1283         if (offset >= NUM_GPRS)
1284                 return NULL;
1285         return gpr_names[offset];
1286 }
1287
1288 static int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
1289 {
1290         unsigned long ksp = kernel_stack_pointer(regs);
1291
1292         return (addr & ~(THREAD_SIZE - 1)) == (ksp & ~(THREAD_SIZE - 1));
1293 }
1294
1295 /**
1296  * regs_get_kernel_stack_nth() - get Nth entry of the stack
1297  * @regs:pt_regs which contains kernel stack pointer.
1298  * @n:stack entry number.
1299  *
1300  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
1301  * is specifined by @regs. If the @n th entry is NOT in the kernel stack,
1302  * this returns 0.
1303  */
1304 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
1305 {
1306         unsigned long addr;
1307
1308         addr = kernel_stack_pointer(regs) + n * sizeof(long);
1309         if (!regs_within_kernel_stack(regs, addr))
1310                 return 0;
1311         return *(unsigned long *)addr;
1312 }