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 long
 551 ia64_sync_kernel_rbs (struct task_struct *child, struct switch_stack *sw,
 552                 unsigned long user_rbs_start, unsigned long user_rbs_end)
 553 {
 554         unsigned long addr, val;
 555         long ret;
 556
 557         /* now copy word for word from user rbs to kernel rbs: */
 558         for (addr = user_rbs_start; addr < user_rbs_end; addr += 8) {
 559                 if (access_process_vm(child, addr, &val, sizeof(val), 0)
 560                                 != sizeof(val))
 561                         return -EIO;
 562
 563                 ret = ia64_poke(child, sw, user_rbs_end, addr, val);
 564                 if (ret < 0)
 565                         return ret;
 566         }
 567         return 0;
 568 }
 569
 570 typedef long (*syncfunc_t)(struct task_struct *, struct switch_stack *,
 571                             unsigned long, unsigned long);
 572
 573 static void do_sync_rbs(struct unw_frame_info *info, void *arg)
 574 {
 575         struct pt_regs *pt;
 576         unsigned long urbs_end;
 577         syncfunc_t fn = arg;
 578
 579         if (unw_unwind_to_user(info) < 0)
 580                 return;
 581         pt = task_pt_regs(info->task);
 582         urbs_end = ia64_get_user_rbs_end(info->task, pt, NULL);
 583
 584         fn(info->task, info->sw, pt->ar_bspstore, urbs_end);
 585 }
 586
 587 /*
 588  * when a thread is stopped (ptraced), debugger might change thread's user
 589  * stack (change memory directly), and we must avoid the RSE stored in kernel
 590  * to override user stack (user space's RSE is newer than kernel's in the
 591  * case). To workaround the issue, we copy kernel RSE to user RSE before the
 592  * task is stopped, so user RSE has updated data.  we then copy user RSE to
 593  * kernel after the task is resummed from traced stop and kernel will use the
 594  * newer RSE to return to user. TIF_RESTORE_RSE is the flag to indicate we need
 595  * synchronize user RSE to kernel.
 596  */
 597 void ia64_ptrace_stop(void)
 598 {
 599         if (test_and_set_tsk_thread_flag(current, TIF_RESTORE_RSE))
 600                 return;
 601         tsk_set_notify_resume(current);
 602         unw_init_running(do_sync_rbs, ia64_sync_user_rbs);
 603 }
 604
 605 /*
 606  * This is called to read back the register backing store.
 607  */
 608 void ia64_sync_krbs(void)
 609 {
 610         clear_tsk_thread_flag(current, TIF_RESTORE_RSE);
 611         tsk_clear_notify_resume(current);
 612
 613         unw_init_running(do_sync_rbs, ia64_sync_kernel_rbs);
 614 }
 615
 616 /*
 617  * After PTRACE_ATTACH, a thread's register backing store area in user
 618  * space is assumed to contain correct data whenever the thread is
 619  * stopped.  arch_ptrace_stop takes care of this on tracing stops.
 620  * But if the child was already stopped for job control when we attach
 621  * to it, then it might not ever get into ptrace_stop by the time we
 622  * want to examine the user memory containing the RBS.
 623  */
 624 void
 625 ptrace_attach_sync_user_rbs (struct task_struct *child)
 626 {
 627         int stopped = 0;
 628         struct unw_frame_info info;
 629
 630         /*
 631          * If the child is in TASK_STOPPED, we need to change that to
 632          * TASK_TRACED momentarily while we operate on it.  This ensures
 633          * that the child won't be woken up and return to user mode while
 634          * we are doing the sync.  (It can only be woken up for SIGKILL.)
 635          */
 636
 637         read_lock(&tasklist_lock);
 638         if (child->signal) {
 639                 spin_lock_irq(&child->sighand->siglock);
 640                 if (child->state == TASK_STOPPED &&
 641                     !test_and_set_tsk_thread_flag(child, TIF_RESTORE_RSE)) {
 642                         tsk_set_notify_resume(child);
 643
 644                         child->state = TASK_TRACED;
 645                         stopped = 1;
 646                 }
 647                 spin_unlock_irq(&child->sighand->siglock);
 648         }
 649         read_unlock(&tasklist_lock);
 650
 651         if (!stopped)
 652                 return;
 653
 654         unw_init_from_blocked_task(&info, child);
 655         do_sync_rbs(&info, ia64_sync_user_rbs);
 656
 657         /*
 658          * Now move the child back into TASK_STOPPED if it should be in a
 659          * job control stop, so that SIGCONT can be used to wake it up.
 660          */
 661         read_lock(&tasklist_lock);
 662         if (child->signal) {
 663                 spin_lock_irq(&child->sighand->siglock);
 664                 if (child->state == TASK_TRACED &&
 665                     (child->signal->flags & SIGNAL_STOP_STOPPED)) {
 666                         child->state = TASK_STOPPED;
 667                 }
 668                 spin_unlock_irq(&child->sighand->siglock);
 669         }
 670         read_unlock(&tasklist_lock);
 671 }
 672
 673 static inline int
 674 thread_matches (struct task_struct *thread, unsigned long addr)
 675 {
 676         unsigned long thread_rbs_end;
 677         struct pt_regs *thread_regs;
 678
 679         if (ptrace_check_attach(thread, 0) < 0)
 680                 /*
 681                  * If the thread is not in an attachable state, we'll
 682                  * ignore it.  The net effect is that if ADDR happens
 683                  * to overlap with the portion of the thread's
 684                  * register backing store that is currently residing
 685                  * on the thread's kernel stack, then ptrace() may end
 686                  * up accessing a stale value.  But if the thread
 687                  * isn't stopped, that's a problem anyhow, so we're
 688                  * doing as well as we can...
 689                  */
 690                 return 0;
 691
 692         thread_regs = task_pt_regs(thread);
 693         thread_rbs_end = ia64_get_user_rbs_end(thread, thread_regs, NULL);
 694         if (!on_kernel_rbs(addr, thread_regs->ar_bspstore, thread_rbs_end))
 695                 return 0;
 696
 697         return 1;       /* looks like we've got a winner */
 698 }
 699
 700 /*
 701  * GDB apparently wants to be able to read the register-backing store
 702  * of any thread when attached to a given process.  If we are peeking
 703  * or poking an address that happens to reside in the kernel-backing
 704  * store of another thread, we need to attach to that thread, because
 705  * otherwise we end up accessing stale data.
 706  *
 707  * task_list_lock must be read-locked before calling this routine!
 708  */
 709 static struct task_struct *
 710 find_thread_for_addr (struct task_struct *child, unsigned long addr)
 711 {
 712         struct task_struct *p;
 713         struct mm_struct *mm;
 714         struct list_head *this, *next;
 715         int mm_users;
 716
 717         if (!(mm = get_task_mm(child)))
 718                 return child;
 719
 720         /* -1 because of our get_task_mm(): */
 721         mm_users = atomic_read(&mm->mm_users) - 1;
 722         if (mm_users <= 1)
 723                 goto out;               /* not multi-threaded */
 724
 725         /*
 726          * Traverse the current process' children list.  Every task that
 727          * one attaches to becomes a child.  And it is only attached children
 728          * of the debugger that are of interest (ptrace_check_attach checks
 729          * for this).
 730          */
 731         list_for_each_safe(this, next, &current->children) {
 732                 p = list_entry(this, struct task_struct, sibling);
 733                 if (p->tgid != child->tgid)
 734                         continue;
 735                 if (thread_matches(p, addr)) {
 736                         child = p;
 737                         goto out;
 738                 }
 739         }
 740
 741   out:
 742         mmput(mm);
 743         return child;
 744 }
 745
 746 /*
 747  * Write f32-f127 back to task->thread.fph if it has been modified.
 748  */
 749 inline void
 750 ia64_flush_fph (struct task_struct *task)
 751 {
 752         struct ia64_psr *psr = ia64_psr(task_pt_regs(task));
 753
 754         /*
 755          * Prevent migrating this task while
 756          * we're fiddling with the FPU state
 757          */
 758         preempt_disable();
 759         if (ia64_is_local_fpu_owner(task) && psr->mfh) {
 760                 psr->mfh = 0;
 761                 task->thread.flags |= IA64_THREAD_FPH_VALID;
 762                 ia64_save_fpu(&task->thread.fph[0]);
 763         }
 764         preempt_enable();
 765 }
 766
 767 /*
 768  * Sync the fph state of the task so that it can be manipulated
 769  * through thread.fph.  If necessary, f32-f127 are written back to
 770  * thread.fph or, if the fph state hasn't been used before, thread.fph
 771  * is cleared to zeroes.  Also, access to f32-f127 is disabled to
 772  * ensure that the task picks up the state from thread.fph when it
 773  * executes again.
 774  */
 775 void
 776 ia64_sync_fph (struct task_struct *task)
 777 {
 778         struct ia64_psr *psr = ia64_psr(task_pt_regs(task));
 779
 780         ia64_flush_fph(task);
 781         if (!(task->thread.flags & IA64_THREAD_FPH_VALID)) {
 782                 task->thread.flags |= IA64_THREAD_FPH_VALID;
 783                 memset(&task->thread.fph, 0, sizeof(task->thread.fph));
 784         }
 785         ia64_drop_fpu(task);
 786         psr->dfh = 1;
 787 }
 788
 789 static int
 790 access_fr (struct unw_frame_info *info, int regnum, int hi,
 791            unsigned long *data, int write_access)
 792 {
 793         struct ia64_fpreg fpval;
 794         int ret;
 795
 796         ret = unw_get_fr(info, regnum, &fpval);
 797         if (ret < 0)
 798                 return ret;
 799
 800         if (write_access) {
 801                 fpval.u.bits[hi] = *data;
 802                 ret = unw_set_fr(info, regnum, fpval);
 803         } else
 804                 *data = fpval.u.bits[hi];
 805         return ret;
 806 }
 807
 808 /*
 809  * Change the machine-state of CHILD such that it will return via the normal
 810  * kernel exit-path, rather than the syscall-exit path.
 811  */
 812 static void
 813 convert_to_non_syscall (struct task_struct *child, struct pt_regs  *pt,
 814                         unsigned long cfm)
 815 {
 816         struct unw_frame_info info, prev_info;
 817         unsigned long ip, sp, pr;
 818
 819         unw_init_from_blocked_task(&info, child);
 820         while (1) {
 821                 prev_info = info;
 822                 if (unw_unwind(&info) < 0)
 823                         return;
 824
 825                 unw_get_sp(&info, &sp);
 826                 if ((long)((unsigned long)child + IA64_STK_OFFSET - sp)
 827                     < IA64_PT_REGS_SIZE) {
 828                         dprintk("ptrace.%s: ran off the top of the kernel "
 829                                 "stack\n", __FUNCTION__);
 830                         return;
 831                 }
 832                 if (unw_get_pr (&prev_info, &pr) < 0) {
 833                         unw_get_rp(&prev_info, &ip);
 834                         dprintk("ptrace.%s: failed to read "
 835                                 "predicate register (ip=0x%lx)\n",
 836                                 __FUNCTION__, ip);
 837                         return;
 838                 }
 839                 if (unw_is_intr_frame(&info)
 840                     && (pr & (1UL << PRED_USER_STACK)))
 841                         break;
 842         }
 843
 844         /*
 845          * Note: at the time of this call, the target task is blocked
 846          * in notify_resume_user() and by clearling PRED_LEAVE_SYSCALL
 847          * (aka, "pLvSys") we redirect execution from
 848          * .work_pending_syscall_end to .work_processed_kernel.
 849          */
 850         unw_get_pr(&prev_info, &pr);
 851         pr &= ~((1UL << PRED_SYSCALL) | (1UL << PRED_LEAVE_SYSCALL));
 852         pr |=  (1UL << PRED_NON_SYSCALL);
 853         unw_set_pr(&prev_info, pr);
 854
 855         pt->cr_ifs = (1UL << 63) | cfm;
 856         /*
 857          * Clear the memory that is NOT written on syscall-entry to
 858          * ensure we do not leak kernel-state to user when execution
 859          * resumes.
 860          */
 861         pt->r2 = 0;
 862         pt->r3 = 0;
 863         pt->r14 = 0;
 864         memset(&pt->r16, 0, 16*8);      /* clear r16-r31 */
 865         memset(&pt->f6, 0, 6*16);       /* clear f6-f11 */
 866         pt->b7 = 0;
 867         pt->ar_ccv = 0;
 868         pt->ar_csd = 0;
 869         pt->ar_ssd = 0;
 870 }
 871
 872 static int
 873 access_nat_bits (struct task_struct *child, struct pt_regs *pt,
 874                  struct unw_frame_info *info,
 875                  unsigned long *data, int write_access)
 876 {
 877         unsigned long regnum, nat_bits, scratch_unat, dummy = 0;
 878         char nat = 0;
 879
 880         if (write_access) {
 881                 nat_bits = *data;
 882                 scratch_unat = ia64_put_scratch_nat_bits(pt, nat_bits);
 883                 if (unw_set_ar(info, UNW_AR_UNAT, scratch_unat) < 0) {
 884                         dprintk("ptrace: failed to set ar.unat\n");
 885                         return -1;
 886                 }
 887                 for (regnum = 4; regnum <= 7; ++regnum) {
 888                         unw_get_gr(info, regnum, &dummy, &nat);
 889                         unw_set_gr(info, regnum, dummy,
 890                                    (nat_bits >> regnum) & 1);
 891                 }
 892         } else {
 893                 if (unw_get_ar(info, UNW_AR_UNAT, &scratch_unat) < 0) {
 894                         dprintk("ptrace: failed to read ar.unat\n");
 895                         return -1;
 896                 }
 897                 nat_bits = ia64_get_scratch_nat_bits(pt, scratch_unat);
 898                 for (regnum = 4; regnum <= 7; ++regnum) {
 899                         unw_get_gr(info, regnum, &dummy, &nat);
 900                         nat_bits |= (nat != 0) << regnum;
 901                 }
 902                 *data = nat_bits;
 903         }
 904         return 0;
 905 }
 906
 907 static int
 908 access_uarea (struct task_struct *child, unsigned long addr,
 909               unsigned long *data, int write_access)
 910 {
 911         unsigned long *ptr, regnum, urbs_end, rnat_addr, cfm;
 912         struct switch_stack *sw;
 913         struct pt_regs *pt;
 914 #       define pt_reg_addr(pt, reg)     ((void *)                           \
 915                                          ((unsigned long) (pt)              \
 916                                           + offsetof(struct pt_regs, reg)))
 917
 918
 919         pt = task_pt_regs(child);
 920         sw = (struct switch_stack *) (child->thread.ksp + 16);
 921
 922         if ((addr & 0x7) != 0) {
 923                 dprintk("ptrace: unaligned register address 0x%lx\n", addr);
 924                 return -1;
 925         }
 926
 927         if (addr < PT_F127 + 16) {
 928                 /* accessing fph */
 929                 if (write_access)
 930                         ia64_sync_fph(child);
 931                 else
 932                         ia64_flush_fph(child);
 933                 ptr = (unsigned long *)
 934                         ((unsigned long) &child->thread.fph + addr);
 935         } else if ((addr >= PT_F10) && (addr < PT_F11 + 16)) {
 936                 /* scratch registers untouched by kernel (saved in pt_regs) */
 937                 ptr = pt_reg_addr(pt, f10) + (addr - PT_F10);
 938         } else if (addr >= PT_F12 && addr < PT_F15 + 16) {
 939                 /*
 940                  * Scratch registers untouched by kernel (saved in
 941                  * switch_stack).
 942                  */
 943                 ptr = (unsigned long *) ((long) sw
 944                                          + (addr - PT_NAT_BITS - 32));
 945         } else if (addr < PT_AR_LC + 8) {
 946                 /* preserved state: */
 947                 struct unw_frame_info info;
 948                 char nat = 0;
 949                 int ret;
 950
 951                 unw_init_from_blocked_task(&info, child);
 952                 if (unw_unwind_to_user(&info) < 0)
 953                         return -1;
 954
 955                 switch (addr) {
 956                       case PT_NAT_BITS:
 957                         return access_nat_bits(child, pt, &info,
 958                                                data, write_access);
 959
 960                       case PT_R4: case PT_R5: case PT_R6: case PT_R7:
 961                         if (write_access) {
 962                                 /* read NaT bit first: */
 963                                 unsigned long dummy;
 964
 965                                 ret = unw_get_gr(&info, (addr - PT_R4)/8 + 4,
 966                                                  &dummy, &nat);
 967                                 if (ret < 0)
 968                                         return ret;
 969                         }
 970                         return unw_access_gr(&info, (addr - PT_R4)/8 + 4, data,
 971                                              &nat, write_access);
 972
 973                       case PT_B1: case PT_B2: case PT_B3:
 974                       case PT_B4: case PT_B5:
 975                         return unw_access_br(&info, (addr - PT_B1)/8 + 1, data,
 976                                              write_access);
 977
 978                       case PT_AR_EC:
 979                         return unw_access_ar(&info, UNW_AR_EC, data,
 980                                              write_access);
 981
 982                       case PT_AR_LC:
 983                         return unw_access_ar(&info, UNW_AR_LC, data,
 984                                              write_access);
 985
 986                       default:
 987                         if (addr >= PT_F2 && addr < PT_F5 + 16)
 988                                 return access_fr(&info, (addr - PT_F2)/16 + 2,
 989                                                  (addr & 8) != 0, data,
 990                                                  write_access);
 991                         else if (addr >= PT_F16 && addr < PT_F31 + 16)
 992                                 return access_fr(&info,
 993                                                  (addr - PT_F16)/16 + 16,
 994                                                  (addr & 8) != 0,
 995                                                  data, write_access);
 996                         else {
 997                                 dprintk("ptrace: rejecting access to register "
 998                                         "address 0x%lx\n", addr);
 999                                 return -1;
1000                         }
1001                 }
1002         } else if (addr < PT_F9+16) {
1003                 /* scratch state */
1004                 switch (addr) {
1005                       case PT_AR_BSP:
1006                         /*
1007                          * By convention, we use PT_AR_BSP to refer to
1008                          * the end of the user-level backing store.
1009                          * Use ia64_rse_skip_regs(PT_AR_BSP, -CFM.sof)
1010                          * to get the real value of ar.bsp at the time
1011                          * the kernel was entered.
1012                          *
1013                          * Furthermore, when changing the contents of
1014                          * PT_AR_BSP (or PT_CFM) we MUST copy any
1015                          * users-level stacked registers that are
1016                          * stored on the kernel stack back to
1017                          * user-space because otherwise, we might end
1018                          * up clobbering kernel stacked registers.
1019                          * Also, if this happens while the task is
1020                          * blocked in a system call, which convert the
1021                          * state such that the non-system-call exit
1022                          * path is used.  This ensures that the proper
1023                          * state will be picked up when resuming
1024                          * execution.  However, it *also* means that
1025                          * once we write PT_AR_BSP/PT_CFM, it won't be
1026                          * possible to modify the syscall arguments of
1027                          * the pending system call any longer.  This
1028                          * shouldn't be an issue because modifying
1029                          * PT_AR_BSP/PT_CFM generally implies that
1030                          * we're either abandoning the pending system
1031                          * call or that we defer it's re-execution
1032                          * (e.g., due to GDB doing an inferior
1033                          * function call).
1034                          */
1035                         urbs_end = ia64_get_user_rbs_end(child, pt, &cfm);
1036                         if (write_access) {
1037                                 if (*data != urbs_end) {
1038                                         if (ia64_sync_user_rbs(child, sw,
1039                                                                pt->ar_bspstore,
1040                                                                urbs_end) < 0)
1041                                                 return -1;
1042                                         if (in_syscall(pt))
1043                                                 convert_to_non_syscall(child,
1044                                                                        pt,
1045                                                                        cfm);
1046                                         /*
1047                                          * Simulate user-level write
1048                                          * of ar.bsp:
1049                                          */
1050                                         pt->loadrs = 0;
1051                                         pt->ar_bspstore = *data;
1052                                 }
1053                         } else
1054                                 *data = urbs_end;
1055                         return 0;
1056
1057                       case PT_CFM:
1058                         urbs_end = ia64_get_user_rbs_end(child, pt, &cfm);
1059                         if (write_access) {
1060                                 if (((cfm ^ *data) & PFM_MASK) != 0) {
1061                                         if (ia64_sync_user_rbs(child, sw,
1062                                                                pt->ar_bspstore,
1063                                                                urbs_end) < 0)
1064                                                 return -1;
1065                                         if (in_syscall(pt))
1066                                                 convert_to_non_syscall(child,
1067                                                                        pt,
1068                                                                        cfm);
1069                                         pt->cr_ifs = ((pt->cr_ifs & ~PFM_MASK)
1070                                                       | (*data & PFM_MASK));
1071                                 }
1072                         } else
1073                                 *data = cfm;
1074                         return 0;
1075
1076                       case PT_CR_IPSR:
1077                         if (write_access) {
1078                                 unsigned long tmp = *data;
1079                                 /* psr.ri==3 is a reserved value: SDM 2:25 */
1080                                 if ((tmp & IA64_PSR_RI) == IA64_PSR_RI)
1081                                         tmp &= ~IA64_PSR_RI;
1082                                 pt->cr_ipsr = ((tmp & IPSR_MASK)
1083                                                | (pt->cr_ipsr & ~IPSR_MASK));
1084                         } else
1085                                 *data = (pt->cr_ipsr & IPSR_MASK);
1086                         return 0;
1087
1088                       case PT_AR_RSC:
1089                         if (write_access)
1090                                 pt->ar_rsc = *data | (3 << 2); /* force PL3 */
1091                         else
1092                                 *data = pt->ar_rsc;
1093                         return 0;
1094
1095                       case PT_AR_RNAT:
1096                         urbs_end = ia64_get_user_rbs_end(child, pt, NULL);
1097                         rnat_addr = (long) ia64_rse_rnat_addr((long *)
1098                                                               urbs_end);
1099                         if (write_access)
1100                                 return ia64_poke(child, sw, urbs_end,
1101                                                  rnat_addr, *data);
1102                         else
1103                                 return ia64_peek(child, sw, urbs_end,
1104                                                  rnat_addr, data);
1105
1106                       case PT_R1:
1107                         ptr = pt_reg_addr(pt, r1);
1108                         break;
1109                       case PT_R2:  case PT_R3:
1110                         ptr = pt_reg_addr(pt, r2) + (addr - PT_R2);
1111                         break;
1112                       case PT_R8:  case PT_R9:  case PT_R10: case PT_R11:
1113                         ptr = pt_reg_addr(pt, r8) + (addr - PT_R8);
1114                         break;
1115                       case PT_R12: case PT_R13:
1116                         ptr = pt_reg_addr(pt, r12) + (addr - PT_R12);
1117                         break;
1118                       case PT_R14:
1119                         ptr = pt_reg_addr(pt, r14);
1120                         break;
1121                       case PT_R15:
1122                         ptr = pt_reg_addr(pt, r15);
1123                         break;
1124                       case PT_R16: case PT_R17: case PT_R18: case PT_R19:
1125                       case PT_R20: case PT_R21: case PT_R22: case PT_R23:
1126                       case PT_R24: case PT_R25: case PT_R26: case PT_R27:
1127                       case PT_R28: case PT_R29: case PT_R30: case PT_R31:
1128                         ptr = pt_reg_addr(pt, r16) + (addr - PT_R16);
1129                         break;
1130                       case PT_B0:
1131                         ptr = pt_reg_addr(pt, b0);
1132                         break;
1133                       case PT_B6:
1134                         ptr = pt_reg_addr(pt, b6);
1135                         break;
1136                       case PT_B7:
1137                         ptr = pt_reg_addr(pt, b7);
1138                         break;
1139                       case PT_F6:  case PT_F6+8: case PT_F7: case PT_F7+8:
1140                       case PT_F8:  case PT_F8+8: case PT_F9: case PT_F9+8:
1141                         ptr = pt_reg_addr(pt, f6) + (addr - PT_F6);
1142                         break;
1143                       case PT_AR_BSPSTORE:
1144                         ptr = pt_reg_addr(pt, ar_bspstore);
1145                         break;
1146                       case PT_AR_UNAT:
1147                         ptr = pt_reg_addr(pt, ar_unat);
1148                         break;
1149                       case PT_AR_PFS:
1150                         ptr = pt_reg_addr(pt, ar_pfs);
1151                         break;
1152                       case PT_AR_CCV:
1153                         ptr = pt_reg_addr(pt, ar_ccv);
1154                         break;
1155                       case PT_AR_FPSR:
1156                         ptr = pt_reg_addr(pt, ar_fpsr);
1157                         break;
1158                       case PT_CR_IIP:
1159                         ptr = pt_reg_addr(pt, cr_iip);
1160                         break;
1161                       case PT_PR:
1162                         ptr = pt_reg_addr(pt, pr);
1163                         break;
1164                         /* scratch register */
1165
1166                       default:
1167                         /* disallow accessing anything else... */
1168                         dprintk("ptrace: rejecting access to register "
1169                                 "address 0x%lx\n", addr);
1170                         return -1;
1171                 }
1172         } else if (addr <= PT_AR_SSD) {
1173                 ptr = pt_reg_addr(pt, ar_csd) + (addr - PT_AR_CSD);
1174         } else {
1175                 /* access debug registers */
1176
1177                 if (addr >= PT_IBR) {
1178                         regnum = (addr - PT_IBR) >> 3;
1179                         ptr = &child->thread.ibr[0];
1180                 } else {
1181                         regnum = (addr - PT_DBR) >> 3;
1182                         ptr = &child->thread.dbr[0];
1183                 }
1184
1185                 if (regnum >= 8) {
1186                         dprintk("ptrace: rejecting access to register "
1187                                 "address 0x%lx\n", addr);
1188                         return -1;
1189                 }
1190 #ifdef CONFIG_PERFMON
1191                 /*
1192                  * Check if debug registers are used by perfmon. This
1193                  * test must be done once we know that we can do the
1194                  * operation, i.e. the arguments are all valid, but
1195                  * before we start modifying the state.
1196                  *
1197                  * Perfmon needs to keep a count of how many processes
1198                  * are trying to modify the debug registers for system
1199                  * wide monitoring sessions.
1200                  *
1201                  * We also include read access here, because they may
1202                  * cause the PMU-installed debug register state
1203                  * (dbr[], ibr[]) to be reset. The two arrays are also
1204                  * used by perfmon, but we do not use
1205                  * IA64_THREAD_DBG_VALID. The registers are restored
1206                  * by the PMU context switch code.
1207                  */
1208                 if (pfm_use_debug_registers(child)) return -1;
1209 #endif
1210
1211                 if (!(child->thread.flags & IA64_THREAD_DBG_VALID)) {
1212                         child->thread.flags |= IA64_THREAD_DBG_VALID;
1213                         memset(child->thread.dbr, 0,
1214                                sizeof(child->thread.dbr));
1215                         memset(child->thread.ibr, 0,
1216                                sizeof(child->thread.ibr));
1217                 }
1218
1219                 ptr += regnum;
1220
1221                 if ((regnum & 1) && write_access) {
1222                         /* don't let the user set kernel-level breakpoints: */
1223                         *ptr = *data & ~(7UL << 56);
1224                         return 0;
1225                 }
1226         }
1227         if (write_access)
1228                 *ptr = *data;
1229         else
1230                 *data = *ptr;
1231         return 0;
1232 }
1233
1234 static long
1235 ptrace_getregs (struct task_struct *child, struct pt_all_user_regs __user *ppr)
1236 {
1237         unsigned long psr, ec, lc, rnat, bsp, cfm, nat_bits, val;
1238         struct unw_frame_info info;
1239         struct ia64_fpreg fpval;
1240         struct switch_stack *sw;
1241         struct pt_regs *pt;
1242         long ret, retval = 0;
1243         char nat = 0;
1244         int i;
1245
1246         if (!access_ok(VERIFY_WRITE, ppr, sizeof(struct pt_all_user_regs)))
1247                 return -EIO;
1248
1249         pt = task_pt_regs(child);
1250         sw = (struct switch_stack *) (child->thread.ksp + 16);
1251         unw_init_from_blocked_task(&info, child);
1252         if (unw_unwind_to_user(&info) < 0) {
1253                 return -EIO;
1254         }
1255
1256         if (((unsigned long) ppr & 0x7) != 0) {
1257                 dprintk("ptrace:unaligned register address %p\n", ppr);
1258                 return -EIO;
1259         }
1260
1261         if (access_uarea(child, PT_CR_IPSR, &psr, 0) < 0
1262             || access_uarea(child, PT_AR_EC, &ec, 0) < 0
1263             || access_uarea(child, PT_AR_LC, &lc, 0) < 0
1264             || access_uarea(child, PT_AR_RNAT, &rnat, 0) < 0
1265             || access_uarea(child, PT_AR_BSP, &bsp, 0) < 0
1266             || access_uarea(child, PT_CFM, &cfm, 0)
1267             || access_uarea(child, PT_NAT_BITS, &nat_bits, 0))
1268                 return -EIO;
1269
1270         /* control regs */
1271
1272         retval |= __put_user(pt->cr_iip, &ppr->cr_iip);
1273         retval |= __put_user(psr, &ppr->cr_ipsr);
1274
1275         /* app regs */
1276
1277         retval |= __put_user(pt->ar_pfs, &ppr->ar[PT_AUR_PFS]);
1278         retval |= __put_user(pt->ar_rsc, &ppr->ar[PT_AUR_RSC]);
1279         retval |= __put_user(pt->ar_bspstore, &ppr->ar[PT_AUR_BSPSTORE]);
1280         retval |= __put_user(pt->ar_unat, &ppr->ar[PT_AUR_UNAT]);
1281         retval |= __put_user(pt->ar_ccv, &ppr->ar[PT_AUR_CCV]);
1282         retval |= __put_user(pt->ar_fpsr, &ppr->ar[PT_AUR_FPSR]);
1283
1284         retval |= __put_user(ec, &ppr->ar[PT_AUR_EC]);
1285         retval |= __put_user(lc, &ppr->ar[PT_AUR_LC]);
1286         retval |= __put_user(rnat, &ppr->ar[PT_AUR_RNAT]);
1287         retval |= __put_user(bsp, &ppr->ar[PT_AUR_BSP]);
1288         retval |= __put_user(cfm, &ppr->cfm);
1289
1290         /* gr1-gr3 */
1291
1292         retval |= __copy_to_user(&ppr->gr[1], &pt->r1, sizeof(long));
1293         retval |= __copy_to_user(&ppr->gr[2], &pt->r2, sizeof(long) *2);
1294
1295         /* gr4-gr7 */
1296
1297         for (i = 4; i < 8; i++) {
1298                 if (unw_access_gr(&info, i, &val, &nat, 0) < 0)
1299                         return -EIO;
1300                 retval |= __put_user(val, &ppr->gr[i]);
1301         }
1302
1303         /* gr8-gr11 */
1304
1305         retval |= __copy_to_user(&ppr->gr[8], &pt->r8, sizeof(long) * 4);
1306
1307         /* gr12-gr15 */
1308
1309         retval |= __copy_to_user(&ppr->gr[12], &pt->r12, sizeof(long) * 2);
1310         retval |= __copy_to_user(&ppr->gr[14], &pt->r14, sizeof(long));
1311         retval |= __copy_to_user(&ppr->gr[15], &pt->r15, sizeof(long));
1312
1313         /* gr16-gr31 */
1314
1315         retval |= __copy_to_user(&ppr->gr[16], &pt->r16, sizeof(long) * 16);
1316
1317         /* b0 */
1318
1319         retval |= __put_user(pt->b0, &ppr->br[0]);
1320
1321         /* b1-b5 */
1322
1323         for (i = 1; i < 6; i++) {
1324                 if (unw_access_br(&info, i, &val, 0) < 0)
1325                         return -EIO;
1326                 __put_user(val, &ppr->br[i]);
1327         }
1328
1329         /* b6-b7 */
1330
1331         retval |= __put_user(pt->b6, &ppr->br[6]);
1332         retval |= __put_user(pt->b7, &ppr->br[7]);
1333
1334         /* fr2-fr5 */
1335
1336         for (i = 2; i < 6; i++) {
1337                 if (unw_get_fr(&info, i, &fpval) < 0)
1338                         return -EIO;
1339                 retval |= __copy_to_user(&ppr->fr[i], &fpval, sizeof (fpval));
1340         }
1341
1342         /* fr6-fr11 */
1343
1344         retval |= __copy_to_user(&ppr->fr[6], &pt->f6,
1345                                  sizeof(struct ia64_fpreg) * 6);
1346
1347         /* fp scratch regs(12-15) */
1348
1349         retval |= __copy_to_user(&ppr->fr[12], &sw->f12,
1350                                  sizeof(struct ia64_fpreg) * 4);
1351
1352         /* fr16-fr31 */
1353
1354         for (i = 16; i < 32; i++) {
1355                 if (unw_get_fr(&info, i, &fpval) < 0)
1356                         return -EIO;
1357                 retval |= __copy_to_user(&ppr->fr[i], &fpval, sizeof (fpval));
1358         }
1359
1360         /* fph */
1361
1362         ia64_flush_fph(child);
1363         retval |= __copy_to_user(&ppr->fr[32], &child->thread.fph,
1364                                  sizeof(ppr->fr[32]) * 96);
1365
1366         /*  preds */
1367
1368         retval |= __put_user(pt->pr, &ppr->pr);
1369
1370         /* nat bits */
1371
1372         retval |= __put_user(nat_bits, &ppr->nat);
1373
1374         ret = retval ? -EIO : 0;
1375         return ret;
1376 }
1377
1378 static long
1379 ptrace_setregs (struct task_struct *child, struct pt_all_user_regs __user *ppr)
1380 {
1381         unsigned long psr, rsc, ec, lc, rnat, bsp, cfm, nat_bits, val = 0;
1382         struct unw_frame_info info;
1383         struct switch_stack *sw;
1384         struct ia64_fpreg fpval;
1385         struct pt_regs *pt;
1386         long ret, retval = 0;
1387         int i;
1388
1389         memset(&fpval, 0, sizeof(fpval));
1390
1391         if (!access_ok(VERIFY_READ, ppr, sizeof(struct pt_all_user_regs)))
1392                 return -EIO;
1393
1394         pt = task_pt_regs(child);
1395         sw = (struct switch_stack *) (child->thread.ksp + 16);
1396         unw_init_from_blocked_task(&info, child);
1397         if (unw_unwind_to_user(&info) < 0) {
1398                 return -EIO;
1399         }
1400
1401         if (((unsigned long) ppr & 0x7) != 0) {
1402                 dprintk("ptrace:unaligned register address %p\n", ppr);
1403                 return -EIO;
1404         }
1405
1406         /* control regs */
1407
1408         retval |= __get_user(pt->cr_iip, &ppr->cr_iip);
1409         retval |= __get_user(psr, &ppr->cr_ipsr);
1410
1411         /* app regs */
1412
1413         retval |= __get_user(pt->ar_pfs, &ppr->ar[PT_AUR_PFS]);
1414         retval |= __get_user(rsc, &ppr->ar[PT_AUR_RSC]);
1415         retval |= __get_user(pt->ar_bspstore, &ppr->ar[PT_AUR_BSPSTORE]);
1416         retval |= __get_user(pt->ar_unat, &ppr->ar[PT_AUR_UNAT]);
1417         retval |= __get_user(pt->ar_ccv, &ppr->ar[PT_AUR_CCV]);
1418         retval |= __get_user(pt->ar_fpsr, &ppr->ar[PT_AUR_FPSR]);
1419
1420         retval |= __get_user(ec, &ppr->ar[PT_AUR_EC]);
1421         retval |= __get_user(lc, &ppr->ar[PT_AUR_LC]);
1422         retval |= __get_user(rnat, &ppr->ar[PT_AUR_RNAT]);
1423         retval |= __get_user(bsp, &ppr->ar[PT_AUR_BSP]);
1424         retval |= __get_user(cfm, &ppr->cfm);
1425
1426         /* gr1-gr3 */
1427
1428         retval |= __copy_from_user(&pt->r1, &ppr->gr[1], sizeof(long));
1429         retval |= __copy_from_user(&pt->r2, &ppr->gr[2], sizeof(long) * 2);
1430
1431         /* gr4-gr7 */
1432
1433         for (i = 4; i < 8; i++) {
1434                 retval |= __get_user(val, &ppr->gr[i]);
1435                 /* NaT bit will be set via PT_NAT_BITS: */
1436                 if (unw_set_gr(&info, i, val, 0) < 0)
1437                         return -EIO;
1438         }
1439
1440         /* gr8-gr11 */
1441
1442         retval |= __copy_from_user(&pt->r8, &ppr->gr[8], sizeof(long) * 4);
1443
1444         /* gr12-gr15 */
1445
1446         retval |= __copy_from_user(&pt->r12, &ppr->gr[12], sizeof(long) * 2);
1447         retval |= __copy_from_user(&pt->r14, &ppr->gr[14], sizeof(long));
1448         retval |= __copy_from_user(&pt->r15, &ppr->gr[15], sizeof(long));
1449
1450         /* gr16-gr31 */
1451
1452         retval |= __copy_from_user(&pt->r16, &ppr->gr[16], sizeof(long) * 16);
1453
1454         /* b0 */
1455
1456         retval |= __get_user(pt->b0, &ppr->br[0]);
1457
1458         /* b1-b5 */
1459
1460         for (i = 1; i < 6; i++) {
1461                 retval |= __get_user(val, &ppr->br[i]);
1462                 unw_set_br(&info, i, val);
1463         }
1464
1465         /* b6-b7 */
1466
1467         retval |= __get_user(pt->b6, &ppr->br[6]);
1468         retval |= __get_user(pt->b7, &ppr->br[7]);
1469
1470         /* fr2-fr5 */
1471
1472         for (i = 2; i < 6; i++) {
1473                 retval |= __copy_from_user(&fpval, &ppr->fr[i], sizeof(fpval));
1474                 if (unw_set_fr(&info, i, fpval) < 0)
1475                         return -EIO;
1476         }
1477
1478         /* fr6-fr11 */
1479
1480         retval |= __copy_from_user(&pt->f6, &ppr->fr[6],
1481                                    sizeof(ppr->fr[6]) * 6);
1482
1483         /* fp scratch regs(12-15) */
1484
1485         retval |= __copy_from_user(&sw->f12, &ppr->fr[12],
1486                                    sizeof(ppr->fr[12]) * 4);
1487
1488         /* fr16-fr31 */
1489
1490         for (i = 16; i < 32; i++) {
1491                 retval |= __copy_from_user(&fpval, &ppr->fr[i],
1492                                            sizeof(fpval));
1493                 if (unw_set_fr(&info, i, fpval) < 0)
1494                         return -EIO;
1495         }
1496
1497         /* fph */
1498
1499         ia64_sync_fph(child);
1500         retval |= __copy_from_user(&child->thread.fph, &ppr->fr[32],
1501                                    sizeof(ppr->fr[32]) * 96);
1502
1503         /* preds */
1504
1505         retval |= __get_user(pt->pr, &ppr->pr);
1506
1507         /* nat bits */
1508
1509         retval |= __get_user(nat_bits, &ppr->nat);
1510
1511         retval |= access_uarea(child, PT_CR_IPSR, &psr, 1);
1512         retval |= access_uarea(child, PT_AR_RSC, &rsc, 1);
1513         retval |= access_uarea(child, PT_AR_EC, &ec, 1);
1514         retval |= access_uarea(child, PT_AR_LC, &lc, 1);
1515         retval |= access_uarea(child, PT_AR_RNAT, &rnat, 1);
1516         retval |= access_uarea(child, PT_AR_BSP, &bsp, 1);
1517         retval |= access_uarea(child, PT_CFM, &cfm, 1);
1518         retval |= access_uarea(child, PT_NAT_BITS, &nat_bits, 1);
1519
1520         ret = retval ? -EIO : 0;
1521         return ret;
1522 }
1523
1524 /*
1525  * Called by kernel/ptrace.c when detaching..
1526  *
1527  * Make sure the single step bit is not set.
1528  */
1529 void
1530 ptrace_disable (struct task_struct *child)
1531 {
1532         struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child));
1533
1534         /* make sure the single step/taken-branch trap bits are not set: */
1535         clear_tsk_thread_flag(child, TIF_SINGLESTEP);
1536         child_psr->ss = 0;
1537         child_psr->tb = 0;
1538 }
1539
1540 asmlinkage long
1541 sys_ptrace (long request, pid_t pid, unsigned long addr, unsigned long data)
1542 {
1543         struct pt_regs *pt;
1544         unsigned long urbs_end, peek_or_poke;
1545         struct task_struct *child;
1546         struct switch_stack *sw;
1547         long ret;
1548         struct unw_frame_info info;
1549
1550         lock_kernel();
1551         ret = -EPERM;
1552         if (request == PTRACE_TRACEME) {
1553                 ret = ptrace_traceme();
1554                 goto out;
1555         }
1556
1557         peek_or_poke = (request == PTRACE_PEEKTEXT
1558                         || request == PTRACE_PEEKDATA
1559                         || request == PTRACE_POKETEXT
1560                         || request == PTRACE_POKEDATA);
1561         ret = -ESRCH;
1562         read_lock(&tasklist_lock);
1563         {
1564                 child = find_task_by_pid(pid);
1565                 if (child) {
1566                         if (peek_or_poke)
1567                                 child = find_thread_for_addr(child, addr);
1568                         get_task_struct(child);
1569                 }
1570         }
1571         read_unlock(&tasklist_lock);
1572         if (!child)
1573                 goto out;
1574         ret = -EPERM;
1575         if (pid == 1)           /* no messing around with init! */
1576                 goto out_tsk;
1577
1578         if (request == PTRACE_ATTACH) {
1579                 ret = ptrace_attach(child);
1580                 if (!ret)
1581                         arch_ptrace_attach(child);
1582                 goto out_tsk;
1583         }
1584
1585         ret = ptrace_check_attach(child, request == PTRACE_KILL);
1586         if (ret < 0)
1587                 goto out_tsk;
1588
1589         pt = task_pt_regs(child);
1590         sw = (struct switch_stack *) (child->thread.ksp + 16);
1591
1592         switch (request) {
1593               case PTRACE_PEEKTEXT:
1594               case PTRACE_PEEKDATA:
1595                 /* read word at location addr */
1596                 urbs_end = ia64_get_user_rbs_end(child, pt, NULL);
1597                 ret = ia64_peek(child, sw, urbs_end, addr, &data);
1598                 if (ret == 0) {
1599                         ret = data;
1600                         /* ensure "ret" is not mistaken as an error code: */
1601                         force_successful_syscall_return();
1602                 }
1603                 goto out_tsk;
1604
1605               case PTRACE_POKETEXT:
1606               case PTRACE_POKEDATA:
1607                 /* write the word at location addr */
1608                 urbs_end = ia64_get_user_rbs_end(child, pt, NULL);
1609                 ret = ia64_poke(child, sw, urbs_end, addr, data);
1610
1611                 /* Make sure user RBS has the latest data */
1612                 unw_init_from_blocked_task(&info, child);
1613                 do_sync_rbs(&info, ia64_sync_user_rbs);
1614
1615                 goto out_tsk;
1616
1617               case PTRACE_PEEKUSR:
1618                 /* read the word at addr in the USER area */
1619                 if (access_uarea(child, addr, &data, 0) < 0) {
1620                         ret = -EIO;
1621                         goto out_tsk;
1622                 }
1623                 ret = data;
1624                 /* ensure "ret" is not mistaken as an error code */
1625                 force_successful_syscall_return();
1626                 goto out_tsk;
1627
1628               case PTRACE_POKEUSR:
1629                 /* write the word at addr in the USER area */
1630                 if (access_uarea(child, addr, &data, 1) < 0) {
1631                         ret = -EIO;
1632                         goto out_tsk;
1633                 }
1634                 ret = 0;
1635                 goto out_tsk;
1636
1637               case PTRACE_OLD_GETSIGINFO:
1638                 /* for backwards-compatibility */
1639                 ret = ptrace_request(child, PTRACE_GETSIGINFO, addr, data);
1640                 goto out_tsk;
1641
1642               case PTRACE_OLD_SETSIGINFO:
1643                 /* for backwards-compatibility */
1644                 ret = ptrace_request(child, PTRACE_SETSIGINFO, addr, data);
1645                 goto out_tsk;
1646
1647               case PTRACE_SYSCALL:
1648                 /* continue and stop at next (return from) syscall */
1649               case PTRACE_CONT:
1650                 /* restart after signal. */
1651                 ret = -EIO;
1652                 if (!valid_signal(data))
1653                         goto out_tsk;
1654                 if (request == PTRACE_SYSCALL)
1655                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
1656                 else
1657                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
1658                 child->exit_code = data;
1659
1660                 /*
1661                  * Make sure the single step/taken-branch trap bits
1662                  * are not set:
1663                  */
1664                 clear_tsk_thread_flag(child, TIF_SINGLESTEP);
1665                 ia64_psr(pt)->ss = 0;
1666                 ia64_psr(pt)->tb = 0;
1667
1668                 wake_up_process(child);
1669                 ret = 0;
1670                 goto out_tsk;
1671
1672               case PTRACE_KILL:
1673                 /*
1674                  * Make the child exit.  Best I can do is send it a
1675                  * sigkill.  Perhaps it should be put in the status
1676                  * that it wants to exit.
1677                  */
1678                 if (child->exit_state == EXIT_ZOMBIE)
1679                         /* already dead */
1680                         goto out_tsk;
1681                 child->exit_code = SIGKILL;
1682
1683                 ptrace_disable(child);
1684                 wake_up_process(child);
1685                 ret = 0;
1686                 goto out_tsk;
1687
1688               case PTRACE_SINGLESTEP:
1689                 /* let child execute for one instruction */
1690               case PTRACE_SINGLEBLOCK:
1691                 ret = -EIO;
1692                 if (!valid_signal(data))
1693                         goto out_tsk;
1694
1695                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
1696                 set_tsk_thread_flag(child, TIF_SINGLESTEP);
1697                 if (request == PTRACE_SINGLESTEP) {
1698                         ia64_psr(pt)->ss = 1;
1699                 } else {
1700                         ia64_psr(pt)->tb = 1;
1701                 }
1702                 child->exit_code = data;
1703
1704                 /* give it a chance to run. */
1705                 wake_up_process(child);
1706                 ret = 0;
1707                 goto out_tsk;
1708
1709               case PTRACE_DETACH:
1710                 /* detach a process that was attached. */
1711                 ret = ptrace_detach(child, data);
1712                 goto out_tsk;
1713
1714               case PTRACE_GETREGS:
1715                 ret = ptrace_getregs(child,
1716                                      (struct pt_all_user_regs __user *) data);
1717                 goto out_tsk;
1718
1719               case PTRACE_SETREGS:
1720                 ret = ptrace_setregs(child,
1721                                      (struct pt_all_user_regs __user *) data);
1722                 goto out_tsk;
1723
1724               default:
1725                 ret = ptrace_request(child, request, addr, data);
1726                 goto out_tsk;
1727         }
1728   out_tsk:
1729         put_task_struct(child);
1730   out:
1731         unlock_kernel();
1732         return ret;
1733 }
1734
1735
1736 static void
1737 syscall_trace (void)
1738 {
1739         /*
1740          * The 0x80 provides a way for the tracing parent to
1741          * distinguish between a syscall stop and SIGTRAP delivery.
1742          */
1743         ptrace_notify(SIGTRAP
1744                       | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
1745
1746         /*
1747          * This isn't the same as continuing with a signal, but it
1748          * will do for normal use.  strace only continues with a
1749          * signal if the stopping signal is not SIGTRAP.  -brl
1750          */
1751         if (current->exit_code) {
1752                 send_sig(current->exit_code, current, 1);
1753                 current->exit_code = 0;
1754         }
1755 }
1756
1757 /* "asmlinkage" so the input arguments are preserved... */
1758
1759 asmlinkage void
1760 syscall_trace_enter (long arg0, long arg1, long arg2, long arg3,
1761                      long arg4, long arg5, long arg6, long arg7,
1762                      struct pt_regs regs)
1763 {
1764         if (test_thread_flag(TIF_SYSCALL_TRACE)
1765             && (current->ptrace & PT_PTRACED))
1766                 syscall_trace();
1767
1768         /* copy user rbs to kernel rbs */
1769         if (test_thread_flag(TIF_RESTORE_RSE))
1770                 ia64_sync_krbs();
1771
1772         if (unlikely(current->audit_context)) {
1773                 long syscall;
1774                 int arch;
1775
1776                 if (IS_IA32_PROCESS(&regs)) {
1777                         syscall = regs.r1;
1778                         arch = AUDIT_ARCH_I386;
1779                 } else {
1780                         syscall = regs.r15;
1781                         arch = AUDIT_ARCH_IA64;
1782                 }
1783
1784                 audit_syscall_entry(arch, syscall, arg0, arg1, arg2, arg3);
1785         }
1786
1787 }
1788
1789 /* "asmlinkage" so the input arguments are preserved... */
1790
1791 asmlinkage void
1792 syscall_trace_leave (long arg0, long arg1, long arg2, long arg3,
1793                      long arg4, long arg5, long arg6, long arg7,
1794                      struct pt_regs regs)
1795 {
1796         if (unlikely(current->audit_context)) {
1797                 int success = AUDITSC_RESULT(regs.r10);
1798                 long result = regs.r8;
1799
1800                 if (success != AUDITSC_SUCCESS)
1801                         result = -result;
1802                 audit_syscall_exit(success, result);
1803         }
1804
1805         if ((test_thread_flag(TIF_SYSCALL_TRACE)
1806             || test_thread_flag(TIF_SINGLESTEP))
1807             && (current->ptrace & PT_PTRACED))
1808                 syscall_trace();
1809
1810         /* copy user rbs to kernel rbs */
1811         if (test_thread_flag(TIF_RESTORE_RSE))
1812                 ia64_sync_krbs();
1813 }