arch/ia64/kernel/ptrace.c

   1 /*
   2  * Kernel support for the ptrace() and syscall tracing interfaces.
   3  *
   4  * Copyright (C) 1999-2005 Hewlett-Packard Co
   5  *      David Mosberger-Tang <davidm@hpl.hp.com>
   6  *
   7  * Derived from the x86 and Alpha versions.
   8  */
   9 #include <linux/kernel.h>
  10 #include <linux/sched.h>
  11 #include <linux/slab.h>
  12 #include <linux/mm.h>
  13 #include <linux/errno.h>
  14 #include <linux/ptrace.h>
  15 #include <linux/smp_lock.h>
  16 #include <linux/user.h>
  17 #include <linux/security.h>
  18 #include <linux/audit.h>
  19 #include <linux/signal.h>
  20
  21 #include <asm/pgtable.h>
  22 #include <asm/processor.h>
  23 #include <asm/ptrace_offsets.h>
  24 #include <asm/rse.h>
  25 #include <asm/system.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/unwind.h>
  28 #ifdef CONFIG_PERFMON
  29 #include <asm/perfmon.h>
  30 #endif
  31
  32 #include "entry.h"
  33
  34 /*
  35  * Bits in the PSR that we allow ptrace() to change:
  36  *      be, up, ac, mfl, mfh (the user mask; five bits total)
  37  *      db (debug breakpoint fault; one bit)
  38  *      id (instruction debug fault disable; one bit)
  39  *      dd (data debug fault disable; one bit)
  40  *      ri (restart instruction; two bits)
  41  *      is (instruction set; one bit)
  42  */
  43 #define IPSR_MASK (IA64_PSR_UM | IA64_PSR_DB | IA64_PSR_IS      \
  44                    | IA64_PSR_ID | IA64_PSR_DD | IA64_PSR_RI)
  45
  46 #define MASK(nbits)     ((1UL << (nbits)) - 1)  /* mask with NBITS bits set */
  47 #define PFM_MASK        MASK(38)
  48
  49 #define PTRACE_DEBUG    0
  50
  51 #if PTRACE_DEBUG
  52 # define dprintk(format...)     printk(format)
  53 # define inline
  54 #else
  55 # define dprintk(format...)
  56 #endif
  57
  58 /* Return TRUE if PT was created due to kernel-entry via a system-call.  */
  59
  60 static inline int
  61 in_syscall (struct pt_regs *pt)
  62 {
  63         return (long) pt->cr_ifs >= 0;
  64 }
  65
  66 /*
  67  * Collect the NaT bits for r1-r31 from scratch_unat and return a NaT
  68  * bitset where bit i is set iff the NaT bit of register i is set.
  69  */
  70 unsigned long
  71 ia64_get_scratch_nat_bits (struct pt_regs *pt, unsigned long scratch_unat)
  72 {
  73 #       define GET_BITS(first, last, unat)                              \
  74         ({                                                              \
  75                 unsigned long bit = ia64_unat_pos(&pt->r##first);       \
  76                 unsigned long nbits = (last - first + 1);               \
  77                 unsigned long mask = MASK(nbits) << first;              \
  78                 unsigned long dist;                                     \
  79                 if (bit < first)                                        \
  80                         dist = 64 + bit - first;                        \
  81                 else                                                    \
  82                         dist = bit - first;                             \
  83                 ia64_rotr(unat, dist) & mask;                           \
  84         })
  85         unsigned long val;
  86
  87         /*
  88          * Registers that are stored consecutively in struct pt_regs
  89          * can be handled in parallel.  If the register order in
  90          * struct_pt_regs changes, this code MUST be updated.
  91          */
  92         val  = GET_BITS( 1,  1, scratch_unat);
  93         val |= GET_BITS( 2,  3, scratch_unat);
  94         val |= GET_BITS(12, 13, scratch_unat);
  95         val |= GET_BITS(14, 14, scratch_unat);
  96         val |= GET_BITS(15, 15, scratch_unat);
  97         val |= GET_BITS( 8, 11, scratch_unat);
  98         val |= GET_BITS(16, 31, scratch_unat);
  99         return val;
 100
 101 #       undef GET_BITS
 102 }
 103
 104 /*
 105  * Set the NaT bits for the scratch registers according to NAT and
 106  * return the resulting unat (assuming the scratch registers are
 107  * stored in PT).
 108  */
 109 unsigned long
 110 ia64_put_scratch_nat_bits (struct pt_regs *pt, unsigned long nat)
 111 {
 112 #       define PUT_BITS(first, last, nat)                               \
 113         ({                                                              \
 114                 unsigned long bit = ia64_unat_pos(&pt->r##first);       \
 115                 unsigned long nbits = (last - first + 1);               \
 116                 unsigned long mask = MASK(nbits) << first;              \
 117                 long dist;                                              \
 118                 if (bit < first)                                        \
 119                         dist = 64 + bit - first;                        \
 120                 else                                                    \
 121                         dist = bit - first;                             \
 122                 ia64_rotl(nat & mask, dist);                            \
 123         })
 124         unsigned long scratch_unat;
 125
 126         /*
 127          * Registers that are stored consecutively in struct pt_regs
 128          * can be handled in parallel.  If the register order in
 129          * struct_pt_regs changes, this code MUST be updated.
 130          */
 131         scratch_unat  = PUT_BITS( 1,  1, nat);
 132         scratch_unat |= PUT_BITS( 2,  3, nat);
 133         scratch_unat |= PUT_BITS(12, 13, nat);
 134         scratch_unat |= PUT_BITS(14, 14, nat);
 135         scratch_unat |= PUT_BITS(15, 15, nat);
 136         scratch_unat |= PUT_BITS( 8, 11, nat);
 137         scratch_unat |= PUT_BITS(16, 31, nat);
 138
 139         return scratch_unat;
 140
 141 #       undef PUT_BITS
 142 }
 143
 144 #define IA64_MLX_TEMPLATE       0x2
 145 #define IA64_MOVL_OPCODE        6
 146
 147 void
 148 ia64_increment_ip (struct pt_regs *regs)
 149 {
 150         unsigned long w0, ri = ia64_psr(regs)->ri + 1;
 151
 152         if (ri > 2) {
 153                 ri = 0;
 154                 regs->cr_iip += 16;
 155         } else if (ri == 2) {
 156                 get_user(w0, (char __user *) regs->cr_iip + 0);
 157                 if (((w0 >> 1) & 0xf) == IA64_MLX_TEMPLATE) {
 158                         /*
 159                          * rfi'ing to slot 2 of an MLX bundle causes
 160                          * an illegal operation fault.  We don't want
 161                          * that to happen...
 162                          */
 163                         ri = 0;
 164                         regs->cr_iip += 16;
 165                 }
 166         }
 167         ia64_psr(regs)->ri = ri;
 168 }
 169
 170 void
 171 ia64_decrement_ip (struct pt_regs *regs)
 172 {
 173         unsigned long w0, ri = ia64_psr(regs)->ri - 1;
 174
 175         if (ia64_psr(regs)->ri == 0) {
 176                 regs->cr_iip -= 16;
 177                 ri = 2;
 178                 get_user(w0, (char __user *) regs->cr_iip + 0);
 179                 if (((w0 >> 1) & 0xf) == IA64_MLX_TEMPLATE) {
 180                         /*
 181                          * rfi'ing to slot 2 of an MLX bundle causes
 182                          * an illegal operation fault.  We don't want
 183                          * that to happen...
 184                          */
 185                         ri = 1;
 186                 }
 187         }
 188         ia64_psr(regs)->ri = ri;
 189 }
 190
 191 /*
 192  * This routine is used to read an rnat bits that are stored on the
 193  * kernel backing store.  Since, in general, the alignment of the user
 194  * and kernel are different, this is not completely trivial.  In
 195  * essence, we need to construct the user RNAT based on up to two
 196  * kernel RNAT values and/or the RNAT value saved in the child's
 197  * pt_regs.
 198  *
 199  * user rbs
 200  *
 201  * +--------+ <-- lowest address
 202  * | slot62 |
 203  * +--------+
 204  * |  rnat  | 0x....1f8
 205  * +--------+
 206  * | slot00 | \
 207  * +--------+ |
 208  * | slot01 | > child_regs->ar_rnat
 209  * +--------+ |
 210  * | slot02 | /                         kernel rbs
 211  * +--------+                           +--------+
 212  *          <- child_regs->ar_bspstore  | slot61 | <-- krbs
 213  * +- - - - +                           +--------+
 214  *                                      | slot62 |
 215  * +- - - - +                           +--------+
 216  *                                      |  rnat  |
 217  * +- - - - +                           +--------+
 218  *   vrnat                              | slot00 |
 219  * +- - - - +                           +--------+
 220  *                                      =        =
 221  *                                      +--------+
 222  *                                      | slot00 | \
 223  *                                      +--------+ |
 224  *                                      | slot01 | > child_stack->ar_rnat
 225  *                                      +--------+ |
 226  *                                      | slot02 | /
 227  *                                      +--------+
 228  *                                                <--- child_stack->ar_bspstore
 229  *
 230  * The way to think of this code is as follows: bit 0 in the user rnat
 231  * corresponds to some bit N (0 <= N <= 62) in one of the kernel rnat
 232  * value.  The kernel rnat value holding this bit is stored in
 233  * variable rnat0.  rnat1 is loaded with the kernel rnat value that
 234  * form the upper bits of the user rnat value.
 235  *
 236  * Boundary cases:
 237  *
 238  * o when reading the rnat "below" the first rnat slot on the kernel
 239  *   backing store, rnat0/rnat1 are set to 0 and the low order bits are
 240  *   merged in from pt->ar_rnat.
 241  *
 242  * o when reading the rnat "above" the last rnat slot on the kernel
 243  *   backing store, rnat0/rnat1 gets its value from sw->ar_rnat.
 244  */
 245 static unsigned long
 246 get_rnat (struct task_struct *task, struct switch_stack *sw,
 247           unsigned long *krbs, unsigned long *urnat_addr,
 248           unsigned long *urbs_end)
 249 {
 250         unsigned long rnat0 = 0, rnat1 = 0, urnat = 0, *slot0_kaddr;
 251         unsigned long umask = 0, mask, m;
 252         unsigned long *kbsp, *ubspstore, *rnat0_kaddr, *rnat1_kaddr, shift;
 253         long num_regs, nbits;
 254         struct pt_regs *pt;
 255
 256         pt = task_pt_regs(task);
 257         kbsp = (unsigned long *) sw->ar_bspstore;
 258         ubspstore = (unsigned long *) pt->ar_bspstore;
 259
 260         if (urbs_end < urnat_addr)
 261                 nbits = ia64_rse_num_regs(urnat_addr - 63, urbs_end);
 262         else
 263                 nbits = 63;
 264         mask = MASK(nbits);
 265         /*
 266          * First, figure out which bit number slot 0 in user-land maps
 267          * to in the kernel rnat.  Do this by figuring out how many
 268          * register slots we're beyond the user's backingstore and
 269          * then computing the equivalent address in kernel space.
 270          */
 271         num_regs = ia64_rse_num_regs(ubspstore, urnat_addr + 1);
 272         slot0_kaddr = ia64_rse_skip_regs(krbs, num_regs);
 273         shift = ia64_rse_slot_num(slot0_kaddr);
 274         rnat1_kaddr = ia64_rse_rnat_addr(slot0_kaddr);
 275         rnat0_kaddr = rnat1_kaddr - 64;
 276
 277         if (ubspstore + 63 > urnat_addr) {
 278                 /* some bits need to be merged in from pt->ar_rnat */
 279                 umask = MASK(ia64_rse_slot_num(ubspstore)) & mask;
 280                 urnat = (pt->ar_rnat & umask);
 281                 mask &= ~umask;
 282                 if (!mask)
 283                         return urnat;
 284         }
 285
 286         m = mask << shift;
 287         if (rnat0_kaddr >= kbsp)
 288                 rnat0 = sw->ar_rnat;
 289         else if (rnat0_kaddr > krbs)
 290                 rnat0 = *rnat0_kaddr;
 291         urnat |= (rnat0 & m) >> shift;
 292
 293         m = mask >> (63 - shift);
 294         if (rnat1_kaddr >= kbsp)
 295                 rnat1 = sw->ar_rnat;
 296         else if (rnat1_kaddr > krbs)
 297                 rnat1 = *rnat1_kaddr;
 298         urnat |= (rnat1 & m) << (63 - shift);
 299         return urnat;
 300 }
 301
 302 /*
 303  * The reverse of get_rnat.
 304  */
 305 static void
 306 put_rnat (struct task_struct *task, struct switch_stack *sw,
 307           unsigned long *krbs, unsigned long *urnat_addr, unsigned long urnat,
 308           unsigned long *urbs_end)
 309 {
 310         unsigned long rnat0 = 0, rnat1 = 0, *slot0_kaddr, umask = 0, mask, m;
 311         unsigned long *kbsp, *ubspstore, *rnat0_kaddr, *rnat1_kaddr, shift;
 312         long num_regs, nbits;
 313         struct pt_regs *pt;
 314         unsigned long cfm, *urbs_kargs;
 315
 316         pt = task_pt_regs(task);
 317         kbsp = (unsigned long *) sw->ar_bspstore;
 318         ubspstore = (unsigned long *) pt->ar_bspstore;
 319
 320         urbs_kargs = urbs_end;
 321         if (in_syscall(pt)) {
 322                 /*
 323                  * If entered via syscall, don't allow user to set rnat bits
 324                  * for syscall args.
 325                  */
 326                 cfm = pt->cr_ifs;
 327                 urbs_kargs = ia64_rse_skip_regs(urbs_end, -(cfm & 0x7f));
 328         }
 329
 330         if (urbs_kargs >= urnat_addr)
 331                 nbits = 63;
 332         else {
 333                 if ((urnat_addr - 63) >= urbs_kargs)
 334                         return;
 335                 nbits = ia64_rse_num_regs(urnat_addr - 63, urbs_kargs);
 336         }
 337         mask = MASK(nbits);
 338
 339         /*
 340          * First, figure out which bit number slot 0 in user-land maps
 341          * to in the kernel rnat.  Do this by figuring out how many
 342          * register slots we're beyond the user's backingstore and
 343          * then computing the equivalent address in kernel space.
 344          */
 345         num_regs = ia64_rse_num_regs(ubspstore, urnat_addr + 1);
 346         slot0_kaddr = ia64_rse_skip_regs(krbs, num_regs);
 347         shift = ia64_rse_slot_num(slot0_kaddr);
 348         rnat1_kaddr = ia64_rse_rnat_addr(slot0_kaddr);
 349         rnat0_kaddr = rnat1_kaddr - 64;
 350
 351         if (ubspstore + 63 > urnat_addr) {
 352                 /* some bits need to be place in pt->ar_rnat: */
 353                 umask = MASK(ia64_rse_slot_num(ubspstore)) & mask;
 354                 pt->ar_rnat = (pt->ar_rnat & ~umask) | (urnat & umask);
 355                 mask &= ~umask;
 356                 if (!mask)
 357                         return;
 358         }
 359         /*
 360          * Note: Section 11.1 of the EAS guarantees that bit 63 of an
 361          * rnat slot is ignored. so we don't have to clear it here.
 362          */
 363         rnat0 = (urnat << shift);
 364         m = mask << shift;
 365         if (rnat0_kaddr >= kbsp)
 366                 sw->ar_rnat = (sw->ar_rnat & ~m) | (rnat0 & m);
 367         else if (rnat0_kaddr > krbs)
 368                 *rnat0_kaddr = ((*rnat0_kaddr & ~m) | (rnat0 & m));
 369
 370         rnat1 = (urnat >> (63 - shift));
 371         m = mask >> (63 - shift);
 372         if (rnat1_kaddr >= kbsp)
 373                 sw->ar_rnat = (sw->ar_rnat & ~m) | (rnat1 & m);
 374         else if (rnat1_kaddr > krbs)
 375                 *rnat1_kaddr = ((*rnat1_kaddr & ~m) | (rnat1 & m));
 376 }
 377
 378 static inline int
 379 on_kernel_rbs (unsigned long addr, unsigned long bspstore,
 380                unsigned long urbs_end)
 381 {
 382         unsigned long *rnat_addr = ia64_rse_rnat_addr((unsigned long *)
 383                                                       urbs_end);
 384         return (addr >= bspstore && addr <= (unsigned long) rnat_addr);
 385 }
 386
 387 /*
 388  * Read a word from the user-level backing store of task CHILD.  ADDR
 389  * is the user-level address to read the word from, VAL a pointer to
 390  * the return value, and USER_BSP gives the end of the user-level
 391  * backing store (i.e., it's the address that would be in ar.bsp after
 392  * the user executed a "cover" instruction).
 393  *
 394  * This routine takes care of accessing the kernel register backing
 395  * store for those registers that got spilled there.  It also takes
 396  * care of calculating the appropriate RNaT collection words.
 397  */
 398 long
 399 ia64_peek (struct task_struct *child, struct switch_stack *child_stack,
 400            unsigned long user_rbs_end, unsigned long addr, long *val)
 401 {
 402         unsigned long *bspstore, *krbs, regnum, *laddr, *urbs_end, *rnat_addr;
 403         struct pt_regs *child_regs;
 404         size_t copied;
 405         long ret;
 406
 407         urbs_end = (long *) user_rbs_end;
 408         laddr = (unsigned long *) addr;
 409         child_regs = task_pt_regs(child);
 410         bspstore = (unsigned long *) child_regs->ar_bspstore;
 411         krbs = (unsigned long *) child + IA64_RBS_OFFSET/8;
 412         if (on_kernel_rbs(addr, (unsigned long) bspstore,
 413                           (unsigned long) urbs_end))
 414         {
 415                 /*
 416                  * Attempt to read the RBS in an area that's actually
 417                  * on the kernel RBS => read the corresponding bits in
 418                  * the kernel RBS.
 419                  */
 420                 rnat_addr = ia64_rse_rnat_addr(laddr);
 421                 ret = get_rnat(child, child_stack, krbs, rnat_addr, urbs_end);
 422
 423                 if (laddr == rnat_addr) {
 424                         /* return NaT collection word itself */
 425                         *val = ret;
 426                         return 0;
 427                 }
 428
 429                 if (((1UL << ia64_rse_slot_num(laddr)) & ret) != 0) {
 430                         /*
 431                          * It is implementation dependent whether the
 432                          * data portion of a NaT value gets saved on a
 433                          * st8.spill or RSE spill (e.g., see EAS 2.6,
 434                          * 4.4.4.6 Register Spill and Fill).  To get
 435                          * consistent behavior across all possible
 436                          * IA-64 implementations, we return zero in
 437                          * this case.
 438                          */
 439                         *val = 0;
 440                         return 0;
 441                 }
 442
 443                 if (laddr < urbs_end) {
 444                         /*
 445                          * The desired word is on the kernel RBS and
 446                          * is not a NaT.
 447                          */
 448                         regnum = ia64_rse_num_regs(bspstore, laddr);
 449                         *val = *ia64_rse_skip_regs(krbs, regnum);
 450                         return 0;
 451                 }
 452         }
 453         copied = access_process_vm(child, addr, &ret, sizeof(ret), 0);
 454         if (copied != sizeof(ret))
 455                 return -EIO;
 456         *val = ret;
 457         return 0;
 458 }
 459
 460 long
 461 ia64_poke (struct task_struct *child, struct switch_stack *child_stack,
 462            unsigned long user_rbs_end, unsigned long addr, long val)
 463 {
 464         unsigned long *bspstore, *krbs, regnum, *laddr;
 465         unsigned long *urbs_end = (long *) user_rbs_end;
 466         struct pt_regs *child_regs;
 467
 468         laddr = (unsigned long *) addr;
 469         child_regs = task_pt_regs(child);
 470         bspstore = (unsigned long *) child_regs->ar_bspstore;
 471         krbs = (unsigned long *) child + IA64_RBS_OFFSET/8;
 472         if (on_kernel_rbs(addr, (unsigned long) bspstore,
 473                           (unsigned long) urbs_end))
 474         {
 475                 /*
 476                  * Attempt to write the RBS in an area that's actually
 477                  * on the kernel RBS => write the corresponding bits
 478                  * in the kernel RBS.
 479                  */
 480                 if (ia64_rse_is_rnat_slot(laddr))
 481                         put_rnat(child, child_stack, krbs, laddr, val,
 482                                  urbs_end);
 483                 else {
 484                         if (laddr < urbs_end) {
 485                                 regnum = ia64_rse_num_regs(bspstore, laddr);
 486                                 *ia64_rse_skip_regs(krbs, regnum) = val;
 487                         }
 488                 }
 489         } else if (access_process_vm(child, addr, &val, sizeof(val), 1)
 490                    != sizeof(val))
 491                 return -EIO;
 492         return 0;
 493 }
 494
 495 /*
 496  * Calculate the address of the end of the user-level register backing
 497  * store.  This is the address that would have been stored in ar.bsp
 498  * if the user had executed a "cover" instruction right before
 499  * entering the kernel.  If CFMP is not NULL, it is used to return the
 500  * "current frame mask" that was active at the time the kernel was
 501  * entered.
 502  */
 503 unsigned long
 504 ia64_get_user_rbs_end (struct task_struct *child, struct pt_regs *pt,
 505                        unsigned long *cfmp)
 506 {
 507         unsigned long *krbs, *bspstore, cfm = pt->cr_ifs;
 508         long ndirty;
 509
 510         krbs = (unsigned long *) child + IA64_RBS_OFFSET/8;
 511         bspstore = (unsigned long *) pt->ar_bspstore;
 512         ndirty = ia64_rse_num_regs(krbs, krbs + (pt->loadrs >> 19));
 513
 514         if (in_syscall(pt))
 515                 ndirty += (cfm & 0x7f);
 516         else
 517                 cfm &= ~(1UL << 63);    /* clear valid bit */
 518
 519         if (cfmp)
 520                 *cfmp = cfm;
 521         return (unsigned long) ia64_rse_skip_regs(bspstore, ndirty);
 522 }
 523
 524 /*
 525  * Synchronize (i.e, write) the RSE backing store living in kernel
 526  * space to the VM of the CHILD task.  SW and PT are the pointers to
 527  * the switch_stack and pt_regs structures, respectively.
 528  * USER_RBS_END is the user-level address at which the backing store
 529  * ends.
 530  */
 531 long
 532 ia64_sync_user_rbs (struct task_struct *child, struct switch_stack *sw,
 533                     unsigned long user_rbs_start, unsigned long user_rbs_end)
 534 {
 535         unsigned long addr, val;
 536         long ret;
 537
 538         /* now copy word for word from kernel rbs to user rbs: */
 539         for (addr = user_rbs_start; addr < user_rbs_end; addr += 8) {
 540                 ret = ia64_peek(child, sw, user_rbs_end, addr, &val);
 541                 if (ret < 0)
 542                         return ret;
 543                 if (access_process_vm(child, addr, &val, sizeof(val), 1)
 544                     != sizeof(val))
 545                         return -EIO;
 546         }
 547         return 0;
 548 }
 549
 550 static inline int
 551 thread_matches (struct task_struct *thread, unsigned long addr)
 552 {
 553         unsigned long thread_rbs_end;
 554         struct pt_regs *thread_regs;
 555
 556         if (ptrace_check_attach(thread, 0) < 0)
 557                 /*
 558                  * If the thread is not in an attachable state, we'll
 559                  * ignore it.  The net effect is that if ADDR happens
 560                  * to overlap with the portion of the thread's
 561                  * register backing store that is currently residing
 562                  * on the thread's kernel stack, then ptrace() may end
 563                  * up accessing a stale value.  But if the thread
 564                  * isn't stopped, that's a problem anyhow, so we're
 565                  * doing as well as we can...
 566                  */
 567                 return 0;
 568
 569         thread_regs = task_pt_regs(thread);
 570         thread_rbs_end = ia64_get_user_rbs_end(thread, thread_regs, NULL);
 571         if (!on_kernel_rbs(addr, thread_regs->ar_bspstore, thread_rbs_end))
 572                 return 0;
 573
 574         return 1;       /* looks like we've got a winner */
 575 }
 576
 577 /*
 578  * GDB apparently wants to be able to read the register-backing store
 579  * of any thread when attached to a given process.  If we are peeking
 580  * or poking an address that happens to reside in the kernel-backing
 581  * store of another thread, we need to attach to that thread, because
 582  * otherwise we end up accessing stale data.
 583  *
 584  * task_list_lock must be read-locked before calling this routine!
 585  */
 586 static struct task_struct *
 587 find_thread_for_addr (struct task_struct *child, unsigned long addr)
 588 {
 589         struct task_struct *p;
 590         struct mm_struct *mm;
 591         struct list_head *this, *next;
 592         int mm_users;
 593
 594         if (!(mm = get_task_mm(child)))
 595                 return child;
 596
 597         /* -1 because of our get_task_mm(): */
 598         mm_users = atomic_read(&mm->mm_users) - 1;
 599         if (mm_users <= 1)
 600                 goto out;               /* not multi-threaded */
 601
 602         /*
 603          * Traverse the current process' children list.  Every task that
 604          * one attaches to becomes a child.  And it is only attached children
 605          * of the debugger that are of interest (ptrace_check_attach checks
 606          * for this).
 607          */
 608         list_for_each_safe(this, next, &current->children) {
 609                 p = list_entry(this, struct task_struct, sibling);
 610                 if (p->tgid != child->tgid)
 611                         continue;
 612                 if (thread_matches(p, addr)) {
 613                         child = p;
 614                         goto out;
 615                 }
 616         }
 617
 618   out:
 619         mmput(mm);
 620         return child;
 621 }
 622
 623 /*
 624  * Write f32-f127 back to task->thread.fph if it has been modified.
 625  */
 626 inline void
 627 ia64_flush_fph (struct task_struct *task)
 628 {
 629         struct ia64_psr *psr = ia64_psr(task_pt_regs(task));
 630
 631         /*
 632          * Prevent migrating this task while
 633          * we're fiddling with the FPU state
 634          */
 635         preempt_disable();
 636         if (ia64_is_local_fpu_owner(task) && psr->mfh) {
 637                 psr->mfh = 0;
 638                 task->thread.flags |= IA64_THREAD_FPH_VALID;
 639                 ia64_save_fpu(&task->thread.fph[0]);
 640         }
 641         preempt_enable();
 642 }
 643
 644 /*
 645  * Sync the fph state of the task so that it can be manipulated
 646  * through thread.fph.  If necessary, f32-f127 are written back to
 647  * thread.fph or, if the fph state hasn't been used before, thread.fph
 648  * is cleared to zeroes.  Also, access to f32-f127 is disabled to
 649  * ensure that the task picks up the state from thread.fph when it
 650  * executes again.
 651  */
 652 void
 653 ia64_sync_fph (struct task_struct *task)
 654 {
 655         struct ia64_psr *psr = ia64_psr(task_pt_regs(task));
 656
 657         ia64_flush_fph(task);
 658         if (!(task->thread.flags & IA64_THREAD_FPH_VALID)) {
 659                 task->thread.flags |= IA64_THREAD_FPH_VALID;
 660                 memset(&task->thread.fph, 0, sizeof(task->thread.fph));
 661         }
 662         ia64_drop_fpu(task);
 663         psr->dfh = 1;
 664 }
 665
 666 static int
 667 access_fr (struct unw_frame_info *info, int regnum, int hi,
 668            unsigned long *data, int write_access)
 669 {
 670         struct ia64_fpreg fpval;
 671         int ret;
 672
 673         ret = unw_get_fr(info, regnum, &fpval);
 674         if (ret < 0)
 675                 return ret;
 676
 677         if (write_access) {
 678                 fpval.u.bits[hi] = *data;
 679                 ret = unw_set_fr(info, regnum, fpval);
 680         } else
 681                 *data = fpval.u.bits[hi];
 682         return ret;
 683 }
 684
 685 /*
 686  * Change the machine-state of CHILD such that it will return via the normal
 687  * kernel exit-path, rather than the syscall-exit path.
 688  */
 689 static void
 690 convert_to_non_syscall (struct task_struct *child, struct pt_regs  *pt,
 691                         unsigned long cfm)
 692 {
 693         struct unw_frame_info info, prev_info;
 694         unsigned long ip, sp, pr;
 695
 696         unw_init_from_blocked_task(&info, child);
 697         while (1) {
 698                 prev_info = info;
 699                 if (unw_unwind(&info) < 0)
 700                         return;
 701
 702                 unw_get_sp(&info, &sp);
 703                 if ((long)((unsigned long)child + IA64_STK_OFFSET - sp)
 704                     < IA64_PT_REGS_SIZE) {
 705                         dprintk("ptrace.%s: ran off the top of the kernel "
 706                                 "stack\n", __FUNCTION__);
 707                         return;
 708                 }
 709                 if (unw_get_pr (&prev_info, &pr) < 0) {
 710                         unw_get_rp(&prev_info, &ip);
 711                         dprintk("ptrace.%s: failed to read "
 712                                 "predicate register (ip=0x%lx)\n",
 713                                 __FUNCTION__, ip);
 714                         return;
 715                 }
 716                 if (unw_is_intr_frame(&info)
 717                     && (pr & (1UL << PRED_USER_STACK)))
 718                         break;
 719         }
 720
 721         /*
 722          * Note: at the time of this call, the target task is blocked
 723          * in notify_resume_user() and by clearling PRED_LEAVE_SYSCALL
 724          * (aka, "pLvSys") we redirect execution from
 725          * .work_pending_syscall_end to .work_processed_kernel.
 726          */
 727         unw_get_pr(&prev_info, &pr);
 728         pr &= ~((1UL << PRED_SYSCALL) | (1UL << PRED_LEAVE_SYSCALL));
 729         pr |=  (1UL << PRED_NON_SYSCALL);
 730         unw_set_pr(&prev_info, pr);
 731
 732         pt->cr_ifs = (1UL << 63) | cfm;
 733         /*
 734          * Clear the memory that is NOT written on syscall-entry to
 735          * ensure we do not leak kernel-state to user when execution
 736          * resumes.
 737          */
 738         pt->r2 = 0;
 739         pt->r3 = 0;
 740         pt->r14 = 0;
 741         memset(&pt->r16, 0, 16*8);      /* clear r16-r31 */
 742         memset(&pt->f6, 0, 6*16);       /* clear f6-f11 */
 743         pt->b7 = 0;
 744         pt->ar_ccv = 0;
 745         pt->ar_csd = 0;
 746         pt->ar_ssd = 0;
 747 }
 748
 749 static int
 750 access_nat_bits (struct task_struct *child, struct pt_regs *pt,
 751                  struct unw_frame_info *info,
 752                  unsigned long *data, int write_access)
 753 {
 754         unsigned long regnum, nat_bits, scratch_unat, dummy = 0;
 755         char nat = 0;
 756
 757         if (write_access) {
 758                 nat_bits = *data;
 759                 scratch_unat = ia64_put_scratch_nat_bits(pt, nat_bits);
 760                 if (unw_set_ar(info, UNW_AR_UNAT, scratch_unat) < 0) {
 761                         dprintk("ptrace: failed to set ar.unat\n");
 762                         return -1;
 763                 }
 764                 for (regnum = 4; regnum <= 7; ++regnum) {
 765                         unw_get_gr(info, regnum, &dummy, &nat);
 766                         unw_set_gr(info, regnum, dummy,
 767                                    (nat_bits >> regnum) & 1);
 768                 }
 769         } else {
 770                 if (unw_get_ar(info, UNW_AR_UNAT, &scratch_unat) < 0) {
 771                         dprintk("ptrace: failed to read ar.unat\n");
 772                         return -1;
 773                 }
 774                 nat_bits = ia64_get_scratch_nat_bits(pt, scratch_unat);
 775                 for (regnum = 4; regnum <= 7; ++regnum) {
 776                         unw_get_gr(info, regnum, &dummy, &nat);
 777                         nat_bits |= (nat != 0) << regnum;
 778                 }
 779                 *data = nat_bits;
 780         }
 781         return 0;
 782 }
 783
 784 static int
 785 access_uarea (struct task_struct *child, unsigned long addr,
 786               unsigned long *data, int write_access)
 787 {
 788         unsigned long *ptr, regnum, urbs_end, rnat_addr, cfm;
 789         struct switch_stack *sw;
 790         struct pt_regs *pt;
 791 #       define pt_reg_addr(pt, reg)     ((void *)                           \
 792                                          ((unsigned long) (pt)              \
 793                                           + offsetof(struct pt_regs, reg)))
 794
 795
 796         pt = task_pt_regs(child);
 797         sw = (struct switch_stack *) (child->thread.ksp + 16);
 798
 799         if ((addr & 0x7) != 0) {
 800                 dprintk("ptrace: unaligned register address 0x%lx\n", addr);
 801                 return -1;
 802         }
 803
 804         if (addr < PT_F127 + 16) {
 805                 /* accessing fph */
 806                 if (write_access)
 807                         ia64_sync_fph(child);
 808                 else
 809                         ia64_flush_fph(child);
 810                 ptr = (unsigned long *)
 811                         ((unsigned long) &child->thread.fph + addr);
 812         } else if ((addr >= PT_F10) && (addr < PT_F11 + 16)) {
 813                 /* scratch registers untouched by kernel (saved in pt_regs) */
 814                 ptr = pt_reg_addr(pt, f10) + (addr - PT_F10);
 815         } else if (addr >= PT_F12 && addr < PT_F15 + 16) {
 816                 /*
 817                  * Scratch registers untouched by kernel (saved in
 818                  * switch_stack).
 819                  */
 820                 ptr = (unsigned long *) ((long) sw
 821                                          + (addr - PT_NAT_BITS - 32));
 822         } else if (addr < PT_AR_LC + 8) {
 823                 /* preserved state: */
 824                 struct unw_frame_info info;
 825                 char nat = 0;
 826                 int ret;
 827
 828                 unw_init_from_blocked_task(&info, child);
 829                 if (unw_unwind_to_user(&info) < 0)
 830                         return -1;
 831
 832                 switch (addr) {
 833                       case PT_NAT_BITS:
 834                         return access_nat_bits(child, pt, &info,
 835                                                data, write_access);
 836
 837                       case PT_R4: case PT_R5: case PT_R6: case PT_R7:
 838                         if (write_access) {
 839                                 /* read NaT bit first: */
 840                                 unsigned long dummy;
 841
 842                                 ret = unw_get_gr(&info, (addr - PT_R4)/8 + 4,
 843                                                  &dummy, &nat);
 844                                 if (ret < 0)
 845                                         return ret;
 846                         }
 847                         return unw_access_gr(&info, (addr - PT_R4)/8 + 4, data,
 848                                              &nat, write_access);
 849
 850                       case PT_B1: case PT_B2: case PT_B3:
 851                       case PT_B4: case PT_B5:
 852                         return unw_access_br(&info, (addr - PT_B1)/8 + 1, data,
 853                                              write_access);
 854
 855                       case PT_AR_EC:
 856                         return unw_access_ar(&info, UNW_AR_EC, data,
 857                                              write_access);
 858
 859                       case PT_AR_LC:
 860                         return unw_access_ar(&info, UNW_AR_LC, data,
 861                                              write_access);
 862
 863                       default:
 864                         if (addr >= PT_F2 && addr < PT_F5 + 16)
 865                                 return access_fr(&info, (addr - PT_F2)/16 + 2,
 866                                                  (addr & 8) != 0, data,
 867                                                  write_access);
 868                         else if (addr >= PT_F16 && addr < PT_F31 + 16)
 869                                 return access_fr(&info,
 870                                                  (addr - PT_F16)/16 + 16,
 871                                                  (addr & 8) != 0,
 872                                                  data, write_access);
 873                         else {
 874                                 dprintk("ptrace: rejecting access to register "
 875                                         "address 0x%lx\n", addr);
 876                                 return -1;
 877                         }
 878                 }
 879         } else if (addr < PT_F9+16) {
 880                 /* scratch state */
 881                 switch (addr) {
 882                       case PT_AR_BSP:
 883                         /*
 884                          * By convention, we use PT_AR_BSP to refer to
 885                          * the end of the user-level backing store.
 886                          * Use ia64_rse_skip_regs(PT_AR_BSP, -CFM.sof)
 887                          * to get the real value of ar.bsp at the time
 888                          * the kernel was entered.
 889                          *
 890                          * Furthermore, when changing the contents of
 891                          * PT_AR_BSP (or PT_CFM) we MUST copy any
 892                          * users-level stacked registers that are
 893                          * stored on the kernel stack back to
 894                          * user-space because otherwise, we might end
 895                          * up clobbering kernel stacked registers.
 896                          * Also, if this happens while the task is
 897                          * blocked in a system call, which convert the
 898                          * state such that the non-system-call exit
 899                          * path is used.  This ensures that the proper
 900                          * state will be picked up when resuming
 901                          * execution.  However, it *also* means that
 902                          * once we write PT_AR_BSP/PT_CFM, it won't be
 903                          * possible to modify the syscall arguments of
 904                          * the pending system call any longer.  This
 905                          * shouldn't be an issue because modifying
 906                          * PT_AR_BSP/PT_CFM generally implies that
 907                          * we're either abandoning the pending system
 908                          * call or that we defer it's re-execution
 909                          * (e.g., due to GDB doing an inferior
 910                          * function call).
 911                          */
 912                         urbs_end = ia64_get_user_rbs_end(child, pt, &cfm);
 913                         if (write_access) {
 914                                 if (*data != urbs_end) {
 915                                         if (ia64_sync_user_rbs(child, sw,
 916                                                                pt->ar_bspstore,
 917                                                                urbs_end) < 0)
 918                                                 return -1;
 919                                         if (in_syscall(pt))
 920                                                 convert_to_non_syscall(child,
 921                                                                        pt,
 922                                                                        cfm);
 923                                         /*
 924                                          * Simulate user-level write
 925                                          * of ar.bsp:
 926                                          */
 927                                         pt->loadrs = 0;
 928                                         pt->ar_bspstore = *data;
 929                                 }
 930                         } else
 931                                 *data = urbs_end;
 932                         return 0;
 933
 934                       case PT_CFM:
 935                         urbs_end = ia64_get_user_rbs_end(child, pt, &cfm);
 936                         if (write_access) {
 937                                 if (((cfm ^ *data) & PFM_MASK) != 0) {
 938                                         if (ia64_sync_user_rbs(child, sw,
 939                                                                pt->ar_bspstore,
 940                                                                urbs_end) < 0)
 941                                                 return -1;
 942                                         if (in_syscall(pt))
 943                                                 convert_to_non_syscall(child,
 944                                                                        pt,
 945                                                                        cfm);
 946                                         pt->cr_ifs = ((pt->cr_ifs & ~PFM_MASK)
 947                                                       | (*data & PFM_MASK));
 948                                 }
 949                         } else
 950                                 *data = cfm;
 951                         return 0;
 952
 953                       case PT_CR_IPSR:
 954                         if (write_access)
 955                                 pt->cr_ipsr = ((*data & IPSR_MASK)
 956                                                | (pt->cr_ipsr & ~IPSR_MASK));
 957                         else
 958                                 *data = (pt->cr_ipsr & IPSR_MASK);
 959                         return 0;
 960
 961                       case PT_AR_RSC:
 962                         if (write_access)
 963                                 pt->ar_rsc = *data | (3 << 2); /* force PL3 */
 964                         else
 965                                 *data = pt->ar_rsc;
 966                         return 0;
 967
 968                       case PT_AR_RNAT:
 969                         urbs_end = ia64_get_user_rbs_end(child, pt, NULL);
 970                         rnat_addr = (long) ia64_rse_rnat_addr((long *)
 971                                                               urbs_end);
 972                         if (write_access)
 973                                 return ia64_poke(child, sw, urbs_end,
 974                                                  rnat_addr, *data);
 975                         else
 976                                 return ia64_peek(child, sw, urbs_end,
 977                                                  rnat_addr, data);
 978
 979                       case PT_R1:
 980                         ptr = pt_reg_addr(pt, r1);
 981                         break;
 982                       case PT_R2:  case PT_R3:
 983                         ptr = pt_reg_addr(pt, r2) + (addr - PT_R2);
 984                         break;
 985                       case PT_R8:  case PT_R9:  case PT_R10: case PT_R11:
 986                         ptr = pt_reg_addr(pt, r8) + (addr - PT_R8);
 987                         break;
 988                       case PT_R12: case PT_R13:
 989                         ptr = pt_reg_addr(pt, r12) + (addr - PT_R12);
 990                         break;
 991                       case PT_R14:
 992                         ptr = pt_reg_addr(pt, r14);
 993                         break;
 994                       case PT_R15:
 995                         ptr = pt_reg_addr(pt, r15);
 996                         break;
 997                       case PT_R16: case PT_R17: case PT_R18: case PT_R19:
 998                       case PT_R20: case PT_R21: case PT_R22: case PT_R23:
 999                       case PT_R24: case PT_R25: case PT_R26: case PT_R27:
1000                       case PT_R28: case PT_R29: case PT_R30: case PT_R31:
1001                         ptr = pt_reg_addr(pt, r16) + (addr - PT_R16);
1002                         break;
1003                       case PT_B0:
1004                         ptr = pt_reg_addr(pt, b0);
1005                         break;
1006                       case PT_B6:
1007                         ptr = pt_reg_addr(pt, b6);
1008                         break;
1009                       case PT_B7:
1010                         ptr = pt_reg_addr(pt, b7);
1011                         break;
1012                       case PT_F6:  case PT_F6+8: case PT_F7: case PT_F7+8:
1013                       case PT_F8:  case PT_F8+8: case PT_F9: case PT_F9+8:
1014                         ptr = pt_reg_addr(pt, f6) + (addr - PT_F6);
1015                         break;
1016                       case PT_AR_BSPSTORE:
1017                         ptr = pt_reg_addr(pt, ar_bspstore);
1018                         break;
1019                       case PT_AR_UNAT:
1020                         ptr = pt_reg_addr(pt, ar_unat);
1021                         break;
1022                       case PT_AR_PFS:
1023                         ptr = pt_reg_addr(pt, ar_pfs);
1024                         break;
1025                       case PT_AR_CCV:
1026                         ptr = pt_reg_addr(pt, ar_ccv);
1027                         break;
1028                       case PT_AR_FPSR:
1029                         ptr = pt_reg_addr(pt, ar_fpsr);
1030                         break;
1031                       case PT_CR_IIP:
1032                         ptr = pt_reg_addr(pt, cr_iip);
1033                         break;
1034                       case PT_PR:
1035                         ptr = pt_reg_addr(pt, pr);
1036                         break;
1037                         /* scratch register */
1038
1039                       default:
1040                         /* disallow accessing anything else... */
1041                         dprintk("ptrace: rejecting access to register "
1042                                 "address 0x%lx\n", addr);
1043                         return -1;
1044                 }
1045         } else if (addr <= PT_AR_SSD) {
1046                 ptr = pt_reg_addr(pt, ar_csd) + (addr - PT_AR_CSD);
1047         } else {
1048                 /* access debug registers */
1049
1050                 if (addr >= PT_IBR) {
1051                         regnum = (addr - PT_IBR) >> 3;
1052                         ptr = &child->thread.ibr[0];
1053                 } else {
1054                         regnum = (addr - PT_DBR) >> 3;
1055                         ptr = &child->thread.dbr[0];
1056                 }
1057
1058                 if (regnum >= 8) {
1059                         dprintk("ptrace: rejecting access to register "
1060                                 "address 0x%lx\n", addr);
1061                         return -1;
1062                 }
1063 #ifdef CONFIG_PERFMON
1064                 /*
1065                  * Check if debug registers are used by perfmon. This
1066                  * test must be done once we know that we can do the
1067                  * operation, i.e. the arguments are all valid, but
1068                  * before we start modifying the state.
1069                  *
1070                  * Perfmon needs to keep a count of how many processes
1071                  * are trying to modify the debug registers for system
1072                  * wide monitoring sessions.
1073                  *
1074                  * We also include read access here, because they may
1075                  * cause the PMU-installed debug register state
1076                  * (dbr[], ibr[]) to be reset. The two arrays are also
1077                  * used by perfmon, but we do not use
1078                  * IA64_THREAD_DBG_VALID. The registers are restored
1079                  * by the PMU context switch code.
1080                  */
1081                 if (pfm_use_debug_registers(child)) return -1;
1082 #endif
1083
1084                 if (!(child->thread.flags & IA64_THREAD_DBG_VALID)) {
1085                         child->thread.flags |= IA64_THREAD_DBG_VALID;
1086                         memset(child->thread.dbr, 0,
1087                                sizeof(child->thread.dbr));
1088                         memset(child->thread.ibr, 0,
1089                                sizeof(child->thread.ibr));
1090                 }
1091
1092                 ptr += regnum;
1093
1094                 if ((regnum & 1) && write_access) {
1095                         /* don't let the user set kernel-level breakpoints: */
1096                         *ptr = *data & ~(7UL << 56);
1097                         return 0;
1098                 }
1099         }
1100         if (write_access)
1101                 *ptr = *data;
1102         else
1103                 *data = *ptr;
1104         return 0;
1105 }
1106
1107 static long
1108 ptrace_getregs (struct task_struct *child, struct pt_all_user_regs __user *ppr)
1109 {
1110         unsigned long psr, ec, lc, rnat, bsp, cfm, nat_bits, val;
1111         struct unw_frame_info info;
1112         struct ia64_fpreg fpval;
1113         struct switch_stack *sw;
1114         struct pt_regs *pt;
1115         long ret, retval = 0;
1116         char nat = 0;
1117         int i;
1118
1119         if (!access_ok(VERIFY_WRITE, ppr, sizeof(struct pt_all_user_regs)))
1120                 return -EIO;
1121
1122         pt = task_pt_regs(child);
1123         sw = (struct switch_stack *) (child->thread.ksp + 16);
1124         unw_init_from_blocked_task(&info, child);
1125         if (unw_unwind_to_user(&info) < 0) {
1126                 return -EIO;
1127         }
1128
1129         if (((unsigned long) ppr & 0x7) != 0) {
1130                 dprintk("ptrace:unaligned register address %p\n", ppr);
1131                 return -EIO;
1132         }
1133
1134         if (access_uarea(child, PT_CR_IPSR, &psr, 0) < 0
1135             || access_uarea(child, PT_AR_EC, &ec, 0) < 0
1136             || access_uarea(child, PT_AR_LC, &lc, 0) < 0
1137             || access_uarea(child, PT_AR_RNAT, &rnat, 0) < 0
1138             || access_uarea(child, PT_AR_BSP, &bsp, 0) < 0
1139             || access_uarea(child, PT_CFM, &cfm, 0)
1140             || access_uarea(child, PT_NAT_BITS, &nat_bits, 0))
1141                 return -EIO;
1142
1143         /* control regs */
1144
1145         retval |= __put_user(pt->cr_iip, &ppr->cr_iip);
1146         retval |= __put_user(psr, &ppr->cr_ipsr);
1147
1148         /* app regs */
1149
1150         retval |= __put_user(pt->ar_pfs, &ppr->ar[PT_AUR_PFS]);
1151         retval |= __put_user(pt->ar_rsc, &ppr->ar[PT_AUR_RSC]);
1152         retval |= __put_user(pt->ar_bspstore, &ppr->ar[PT_AUR_BSPSTORE]);
1153         retval |= __put_user(pt->ar_unat, &ppr->ar[PT_AUR_UNAT]);
1154         retval |= __put_user(pt->ar_ccv, &ppr->ar[PT_AUR_CCV]);
1155         retval |= __put_user(pt->ar_fpsr, &ppr->ar[PT_AUR_FPSR]);
1156
1157         retval |= __put_user(ec, &ppr->ar[PT_AUR_EC]);
1158         retval |= __put_user(lc, &ppr->ar[PT_AUR_LC]);
1159         retval |= __put_user(rnat, &ppr->ar[PT_AUR_RNAT]);
1160         retval |= __put_user(bsp, &ppr->ar[PT_AUR_BSP]);
1161         retval |= __put_user(cfm, &ppr->cfm);
1162
1163         /* gr1-gr3 */
1164
1165         retval |= __copy_to_user(&ppr->gr[1], &pt->r1, sizeof(long));
1166         retval |= __copy_to_user(&ppr->gr[2], &pt->r2, sizeof(long) *2);
1167
1168         /* gr4-gr7 */
1169
1170         for (i = 4; i < 8; i++) {
1171                 if (unw_access_gr(&info, i, &val, &nat, 0) < 0)
1172                         return -EIO;
1173                 retval |= __put_user(val, &ppr->gr[i]);
1174         }
1175
1176         /* gr8-gr11 */
1177
1178         retval |= __copy_to_user(&ppr->gr[8], &pt->r8, sizeof(long) * 4);
1179
1180         /* gr12-gr15 */
1181
1182         retval |= __copy_to_user(&ppr->gr[12], &pt->r12, sizeof(long) * 2);
1183         retval |= __copy_to_user(&ppr->gr[14], &pt->r14, sizeof(long));
1184         retval |= __copy_to_user(&ppr->gr[15], &pt->r15, sizeof(long));
1185
1186         /* gr16-gr31 */
1187
1188         retval |= __copy_to_user(&ppr->gr[16], &pt->r16, sizeof(long) * 16);
1189
1190         /* b0 */
1191
1192         retval |= __put_user(pt->b0, &ppr->br[0]);
1193
1194         /* b1-b5 */
1195
1196         for (i = 1; i < 6; i++) {
1197                 if (unw_access_br(&info, i, &val, 0) < 0)
1198                         return -EIO;
1199                 __put_user(val, &ppr->br[i]);
1200         }
1201
1202         /* b6-b7 */
1203
1204         retval |= __put_user(pt->b6, &ppr->br[6]);
1205         retval |= __put_user(pt->b7, &ppr->br[7]);
1206
1207         /* fr2-fr5 */
1208
1209         for (i = 2; i < 6; i++) {
1210                 if (unw_get_fr(&info, i, &fpval) < 0)
1211                         return -EIO;
1212                 retval |= __copy_to_user(&ppr->fr[i], &fpval, sizeof (fpval));
1213         }
1214
1215         /* fr6-fr11 */
1216
1217         retval |= __copy_to_user(&ppr->fr[6], &pt->f6,
1218                                  sizeof(struct ia64_fpreg) * 6);
1219
1220         /* fp scratch regs(12-15) */
1221
1222         retval |= __copy_to_user(&ppr->fr[12], &sw->f12,
1223                                  sizeof(struct ia64_fpreg) * 4);
1224
1225         /* fr16-fr31 */
1226
1227         for (i = 16; i < 32; i++) {
1228                 if (unw_get_fr(&info, i, &fpval) < 0)
1229                         return -EIO;
1230                 retval |= __copy_to_user(&ppr->fr[i], &fpval, sizeof (fpval));
1231         }
1232
1233         /* fph */
1234
1235         ia64_flush_fph(child);
1236         retval |= __copy_to_user(&ppr->fr[32], &child->thread.fph,
1237                                  sizeof(ppr->fr[32]) * 96);
1238
1239         /*  preds */
1240
1241         retval |= __put_user(pt->pr, &ppr->pr);
1242
1243         /* nat bits */
1244
1245         retval |= __put_user(nat_bits, &ppr->nat);
1246
1247         ret = retval ? -EIO : 0;
1248         return ret;
1249 }
1250
1251 static long
1252 ptrace_setregs (struct task_struct *child, struct pt_all_user_regs __user *ppr)
1253 {
1254         unsigned long psr, rsc, ec, lc, rnat, bsp, cfm, nat_bits, val = 0;
1255         struct unw_frame_info info;
1256         struct switch_stack *sw;
1257         struct ia64_fpreg fpval;
1258         struct pt_regs *pt;
1259         long ret, retval = 0;
1260         int i;
1261
1262         memset(&fpval, 0, sizeof(fpval));
1263
1264         if (!access_ok(VERIFY_READ, ppr, sizeof(struct pt_all_user_regs)))
1265                 return -EIO;
1266
1267         pt = task_pt_regs(child);
1268         sw = (struct switch_stack *) (child->thread.ksp + 16);
1269         unw_init_from_blocked_task(&info, child);
1270         if (unw_unwind_to_user(&info) < 0) {
1271                 return -EIO;
1272         }
1273
1274         if (((unsigned long) ppr & 0x7) != 0) {
1275                 dprintk("ptrace:unaligned register address %p\n", ppr);
1276                 return -EIO;
1277         }
1278
1279         /* control regs */
1280
1281         retval |= __get_user(pt->cr_iip, &ppr->cr_iip);
1282         retval |= __get_user(psr, &ppr->cr_ipsr);
1283
1284         /* app regs */
1285
1286         retval |= __get_user(pt->ar_pfs, &ppr->ar[PT_AUR_PFS]);
1287         retval |= __get_user(rsc, &ppr->ar[PT_AUR_RSC]);
1288         retval |= __get_user(pt->ar_bspstore, &ppr->ar[PT_AUR_BSPSTORE]);
1289         retval |= __get_user(pt->ar_unat, &ppr->ar[PT_AUR_UNAT]);
1290         retval |= __get_user(pt->ar_ccv, &ppr->ar[PT_AUR_CCV]);
1291         retval |= __get_user(pt->ar_fpsr, &ppr->ar[PT_AUR_FPSR]);
1292
1293         retval |= __get_user(ec, &ppr->ar[PT_AUR_EC]);
1294         retval |= __get_user(lc, &ppr->ar[PT_AUR_LC]);
1295         retval |= __get_user(rnat, &ppr->ar[PT_AUR_RNAT]);
1296         retval |= __get_user(bsp, &ppr->ar[PT_AUR_BSP]);
1297         retval |= __get_user(cfm, &ppr->cfm);
1298
1299         /* gr1-gr3 */
1300
1301         retval |= __copy_from_user(&pt->r1, &ppr->gr[1], sizeof(long));
1302         retval |= __copy_from_user(&pt->r2, &ppr->gr[2], sizeof(long) * 2);
1303
1304         /* gr4-gr7 */
1305
1306         for (i = 4; i < 8; i++) {
1307                 retval |= __get_user(val, &ppr->gr[i]);
1308                 /* NaT bit will be set via PT_NAT_BITS: */
1309                 if (unw_set_gr(&info, i, val, 0) < 0)
1310                         return -EIO;
1311         }
1312
1313         /* gr8-gr11 */
1314
1315         retval |= __copy_from_user(&pt->r8, &ppr->gr[8], sizeof(long) * 4);
1316
1317         /* gr12-gr15 */
1318
1319         retval |= __copy_from_user(&pt->r12, &ppr->gr[12], sizeof(long) * 2);
1320         retval |= __copy_from_user(&pt->r14, &ppr->gr[14], sizeof(long));
1321         retval |= __copy_from_user(&pt->r15, &ppr->gr[15], sizeof(long));
1322
1323         /* gr16-gr31 */
1324
1325         retval |= __copy_from_user(&pt->r16, &ppr->gr[16], sizeof(long) * 16);
1326
1327         /* b0 */
1328
1329         retval |= __get_user(pt->b0, &ppr->br[0]);
1330
1331         /* b1-b5 */
1332
1333         for (i = 1; i < 6; i++) {
1334                 retval |= __get_user(val, &ppr->br[i]);
1335                 unw_set_br(&info, i, val);
1336         }
1337
1338         /* b6-b7 */
1339
1340         retval |= __get_user(pt->b6, &ppr->br[6]);
1341         retval |= __get_user(pt->b7, &ppr->br[7]);
1342
1343         /* fr2-fr5 */
1344
1345         for (i = 2; i < 6; i++) {
1346                 retval |= __copy_from_user(&fpval, &ppr->fr[i], sizeof(fpval));
1347                 if (unw_set_fr(&info, i, fpval) < 0)
1348                         return -EIO;
1349         }
1350
1351         /* fr6-fr11 */
1352
1353         retval |= __copy_from_user(&pt->f6, &ppr->fr[6],
1354                                    sizeof(ppr->fr[6]) * 6);
1355
1356         /* fp scratch regs(12-15) */
1357
1358         retval |= __copy_from_user(&sw->f12, &ppr->fr[12],
1359                                    sizeof(ppr->fr[12]) * 4);
1360
1361         /* fr16-fr31 */
1362
1363         for (i = 16; i < 32; i++) {
1364                 retval |= __copy_from_user(&fpval, &ppr->fr[i],
1365                                            sizeof(fpval));
1366                 if (unw_set_fr(&info, i, fpval) < 0)
1367                         return -EIO;
1368         }
1369
1370         /* fph */
1371
1372         ia64_sync_fph(child);
1373         retval |= __copy_from_user(&child->thread.fph, &ppr->fr[32],
1374                                    sizeof(ppr->fr[32]) * 96);
1375
1376         /* preds */
1377
1378         retval |= __get_user(pt->pr, &ppr->pr);
1379
1380         /* nat bits */
1381
1382         retval |= __get_user(nat_bits, &ppr->nat);
1383
1384         retval |= access_uarea(child, PT_CR_IPSR, &psr, 1);
1385         retval |= access_uarea(child, PT_AR_RSC, &rsc, 1);
1386         retval |= access_uarea(child, PT_AR_EC, &ec, 1);
1387         retval |= access_uarea(child, PT_AR_LC, &lc, 1);
1388         retval |= access_uarea(child, PT_AR_RNAT, &rnat, 1);
1389         retval |= access_uarea(child, PT_AR_BSP, &bsp, 1);
1390         retval |= access_uarea(child, PT_CFM, &cfm, 1);
1391         retval |= access_uarea(child, PT_NAT_BITS, &nat_bits, 1);
1392
1393         ret = retval ? -EIO : 0;
1394         return ret;
1395 }
1396
1397 /*
1398  * Called by kernel/ptrace.c when detaching..
1399  *
1400  * Make sure the single step bit is not set.
1401  */
1402 void
1403 ptrace_disable (struct task_struct *child)
1404 {
1405         struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child));
1406
1407         /* make sure the single step/taken-branch trap bits are not set: */
1408         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
1409         child_psr->ss = 0;
1410         child_psr->tb = 0;
1411 }
1412
1413 asmlinkage long
1414 sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
1415 {
1416         struct pt_regs *pt;
1417         unsigned long urbs_end, peek_or_poke;
1418         struct task_struct *child;
1419         struct switch_stack *sw;
1420         long ret;
1421
1422         lock_kernel();
1423         ret = -EPERM;
1424         if (request == PTRACE_TRACEME) {
1425                 ret = ptrace_traceme();
1426                 goto out;
1427         }
1428
1429         peek_or_poke = (request == PTRACE_PEEKTEXT
1430                         || request == PTRACE_PEEKDATA
1431                         || request == PTRACE_POKETEXT
1432                         || request == PTRACE_POKEDATA);
1433         ret = -ESRCH;
1434         read_lock(&tasklist_lock);
1435         {
1436                 child = find_task_by_pid(pid);
1437                 if (child) {
1438                         if (peek_or_poke)
1439                                 child = find_thread_for_addr(child, addr);
1440                         get_task_struct(child);
1441                 }
1442         }
1443         read_unlock(&tasklist_lock);
1444         if (!child)
1445                 goto out;
1446         ret = -EPERM;
1447         if (pid == 1)           /* no messing around with init! */
1448                 goto out_tsk;
1449
1450         if (request == PTRACE_ATTACH) {
1451                 ret = ptrace_attach(child);
1452                 goto out_tsk;
1453         }
1454
1455         ret = ptrace_check_attach(child, request == PTRACE_KILL);
1456         if (ret < 0)
1457                 goto out_tsk;
1458
1459         pt = task_pt_regs(child);
1460         sw = (struct switch_stack *) (child->thread.ksp + 16);
1461
1462         switch (request) {
1463               case PTRACE_PEEKTEXT:
1464               case PTRACE_PEEKDATA:
1465                 /* read word at location addr */
1466                 urbs_end = ia64_get_user_rbs_end(child, pt, NULL);
1467                 ret = ia64_peek(child, sw, urbs_end, addr, &data);
1468                 if (ret == 0) {
1469                         ret = data;
1470                         /* ensure "ret" is not mistaken as an error code: */
1471                         force_successful_syscall_return();
1472                 }
1473                 goto out_tsk;
1474
1475               case PTRACE_POKETEXT:
1476               case PTRACE_POKEDATA:
1477                 /* write the word at location addr */
1478                 urbs_end = ia64_get_user_rbs_end(child, pt, NULL);
1479                 ret = ia64_poke(child, sw, urbs_end, addr, data);
1480                 goto out_tsk;
1481
1482               case PTRACE_PEEKUSR:
1483                 /* read the word at addr in the USER area */
1484                 if (access_uarea(child, addr, &data, 0) < 0) {
1485                         ret = -EIO;
1486                         goto out_tsk;
1487                 }
1488                 ret = data;
1489                 /* ensure "ret" is not mistaken as an error code */
1490                 force_successful_syscall_return();
1491                 goto out_tsk;
1492
1493               case PTRACE_POKEUSR:
1494                 /* write the word at addr in the USER area */
1495                 if (access_uarea(child, addr, &data, 1) < 0) {
1496                         ret = -EIO;
1497                         goto out_tsk;
1498                 }
1499                 ret = 0;
1500                 goto out_tsk;
1501
1502               case PTRACE_OLD_GETSIGINFO:
1503                 /* for backwards-compatibility */
1504                 ret = ptrace_request(child, PTRACE_GETSIGINFO, addr, data);
1505                 goto out_tsk;
1506
1507               case PTRACE_OLD_SETSIGINFO:
1508                 /* for backwards-compatibility */
1509                 ret = ptrace_request(child, PTRACE_SETSIGINFO, addr, data);
1510                 goto out_tsk;
1511
1512               case PTRACE_SYSCALL:
1513                 /* continue and stop at next (return from) syscall */
1514               case PTRACE_CONT:
1515                 /* restart after signal. */
1516                 ret = -EIO;
1517                 if (!valid_signal(data))
1518                         goto out_tsk;
1519                 if (request == PTRACE_SYSCALL)
1520                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
1521                 else
1522                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
1523                 child->exit_code = data;
1524
1525                 /*
1526                  * Make sure the single step/taken-branch trap bits
1527                  * are not set:
1528                  */
1529                 clear_tsk_thread_flag(child, TIF_SINGLESTEP);
1530                 ia64_psr(pt)->ss = 0;
1531                 ia64_psr(pt)->tb = 0;
1532
1533                 wake_up_process(child);
1534                 ret = 0;
1535                 goto out_tsk;
1536
1537               case PTRACE_KILL:
1538                 /*
1539                  * Make the child exit.  Best I can do is send it a
1540                  * sigkill.  Perhaps it should be put in the status
1541                  * that it wants to exit.
1542                  */
1543                 if (child->exit_state == EXIT_ZOMBIE)
1544                         /* already dead */
1545                         goto out_tsk;
1546                 child->exit_code = SIGKILL;
1547
1548                 ptrace_disable(child);
1549                 wake_up_process(child);
1550                 ret = 0;
1551                 goto out_tsk;
1552
1553               case PTRACE_SINGLESTEP:
1554                 /* let child execute for one instruction */
1555               case PTRACE_SINGLEBLOCK:
1556                 ret = -EIO;
1557                 if (!valid_signal(data))
1558                         goto out_tsk;
1559
1560                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
1561                 set_tsk_thread_flag(child, TIF_SINGLESTEP);
1562                 if (request == PTRACE_SINGLESTEP) {
1563                         ia64_psr(pt)->ss = 1;
1564                 } else {
1565                         ia64_psr(pt)->tb = 1;
1566                 }
1567                 child->exit_code = data;
1568
1569                 /* give it a chance to run. */
1570                 wake_up_process(child);
1571                 ret = 0;
1572                 goto out_tsk;
1573
1574               case PTRACE_DETACH:
1575                 /* detach a process that was attached. */
1576                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
1577                 ret = ptrace_detach(child, data);
1578                 goto out_tsk;
1579
1580               case PTRACE_GETREGS:
1581                 ret = ptrace_getregs(child,
1582                                      (struct pt_all_user_regs __user *) data);
1583                 goto out_tsk;
1584
1585               case PTRACE_SETREGS:
1586                 ret = ptrace_setregs(child,
1587                                      (struct pt_all_user_regs __user *) data);
1588                 goto out_tsk;
1589
1590               default:
1591                 ret = ptrace_request(child, request, addr, data);
1592                 goto out_tsk;
1593         }
1594   out_tsk:
1595         put_task_struct(child);
1596   out:
1597         unlock_kernel();
1598         return ret;
1599 }
1600
1601
1602 static void
1603 syscall_trace (void)
1604 {
1605         /*
1606          * The 0x80 provides a way for the tracing parent to
1607          * distinguish between a syscall stop and SIGTRAP delivery.
1608          */
1609         ptrace_notify(SIGTRAP
1610                       | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
1611
1612         /*
1613          * This isn't the same as continuing with a signal, but it
1614          * will do for normal use.  strace only continues with a
1615          * signal if the stopping signal is not SIGTRAP.  -brl
1616          */
1617         if (current->exit_code) {
1618                 send_sig(current->exit_code, current, 1);
1619                 current->exit_code = 0;
1620         }
1621 }
1622
1623 /* "asmlinkage" so the input arguments are preserved... */
1624
1625 asmlinkage void
1626 syscall_trace_enter (long arg0, long arg1, long arg2, long arg3,
1627                      long arg4, long arg5, long arg6, long arg7,
1628                      struct pt_regs regs)
1629 {
1630         if (test_thread_flag(TIF_SYSCALL_TRACE)
1631             && (current->ptrace & PT_PTRACED))
1632                 syscall_trace();
1633
1634         if (unlikely(current->audit_context)) {
1635                 long syscall;
1636                 int arch;
1637
1638                 if (IS_IA32_PROCESS(&regs)) {
1639                         syscall = regs.r1;
1640                         arch = AUDIT_ARCH_I386;
1641                 } else {
1642                         syscall = regs.r15;
1643                         arch = AUDIT_ARCH_IA64;
1644                 }
1645
1646                 audit_syscall_entry(arch, syscall, arg0, arg1, arg2, arg3);
1647         }
1648
1649 }
1650
1651 /* "asmlinkage" so the input arguments are preserved... */
1652
1653 asmlinkage void
1654 syscall_trace_leave (long arg0, long arg1, long arg2, long arg3,
1655                      long arg4, long arg5, long arg6, long arg7,
1656                      struct pt_regs regs)
1657 {
1658         if (unlikely(current->audit_context)) {
1659                 int success = AUDITSC_RESULT(regs.r10);
1660                 long result = regs.r8;
1661
1662                 if (success != AUDITSC_SUCCESS)
1663                         result = -result;
1664                 audit_syscall_exit(success, result);
1665         }
1666
1667         if ((test_thread_flag(TIF_SYSCALL_TRACE)
1668             || test_thread_flag(TIF_SINGLESTEP))
1669             && (current->ptrace & PT_PTRACED))
1670                 syscall_trace();
1671 }