src/ppc64/Gstep.c

   1 /* libunwind - a platform-independent unwind library
   2    Copyright (C) 2006-2007 IBM
   3    Contributed by
   4      Corey Ashford <cjashfor@us.ibm.com>
   5      Jose Flavio Aguilar Paulino <jflavio@br.ibm.com> <joseflavio@gmail.com>
   6
   7 This file is part of libunwind.
   8
   9 Permission is hereby granted, free of charge, to any person obtaining
  10 a copy of this software and associated documentation files (the
  11 "Software"), to deal in the Software without restriction, including
  12 without limitation the rights to use, copy, modify, merge, publish,
  13 distribute, sublicense, and/or sell copies of the Software, and to
  14 permit persons to whom the Software is furnished to do so, subject to
  15 the following conditions:
  16
  17 The above copyright notice and this permission notice shall be
  18 included in all copies or substantial portions of the Software.
  19
  20 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
  27
  28 #include "unwind_i.h"
  29 #include "ucontext_i.h"
  30 #include <signal.h>
  31
  32 /* This definition originates in /usr/include/asm-ppc64/ptrace.h, but is
  33    defined there only when __KERNEL__ is defined.  We reproduce it here for
  34    our use at the user level in order to locate the ucontext record, which
  35    appears to be at this offset relative to the stack pointer when in the
  36    context of the signal handler return trampoline code -
  37    __kernel_sigtramp_rt64.  */
  38 #define __SIGNAL_FRAMESIZE 128
  39
  40 /* This definition comes from the document "64-bit PowerPC ELF Application
  41    Binary Interface Supplement 1.9", section 3.2.2.
  42    http://www.linux-foundation.org/spec/ELF/ppc64/PPC-elf64abi-1.9.html#STACK */
  43
  44 typedef struct
  45 {
  46   long unsigned back_chain;
  47   long unsigned cr_save;
  48   long unsigned lr_save;
  49   /* many more fields here, but they are unused by this code */
  50 } stack_frame_t;
  51
  52
  53 PROTECTED int
  54 unw_step (unw_cursor_t * cursor)
  55 {
  56   struct cursor *c = (struct cursor *) cursor;
  57   stack_frame_t dummy;
  58   unw_word_t back_chain_offset, lr_save_offset, v_regs_ptr;
  59   struct dwarf_loc back_chain_loc, lr_save_loc, sp_loc, ip_loc, v_regs_loc;
  60   int ret;
  61
  62   Debug (1, "(cursor=%p, ip=0x%016lx)\n", c, (unsigned long) c->dwarf.ip);
  63
  64   if (c->dwarf.ip == 0)
  65     {
  66       /* Unless the cursor or stack is corrupt or uninitialized,
  67          we've most likely hit the top of the stack */
  68       return 0;
  69     }
  70
  71   /* Try DWARF-based unwinding... */
  72
  73   ret = dwarf_step (&c->dwarf);
  74
  75   if (ret < 0 && ret != -UNW_ENOINFO)
  76     {
  77       Debug (2, "returning %d\n", ret);
  78       return ret;
  79     }
  80
  81   if (unlikely (ret < 0))
  82     {
  83       if (likely (!unw_is_signal_frame (cursor)))
  84         {
  85           /* DWARF unwinding failed.  As of 09/26/2006, gcc in 64-bit mode
  86              produces the mandatory level of traceback record in the code, but
  87              I get the impression that this is transitory, that eventually gcc
  88              will not produce any traceback records at all.  So, for now, we
  89              won't bother to try to find and use these records.
  90
  91              We can, however, attempt to unwind the frame by using the callback
  92              chain.  This is very crude, however, and won't be able to unwind
  93              any registers besides the IP, SP, and LR . */
  94
  95           back_chain_offset = ((void *) &dummy.back_chain - (void *) &dummy);
  96           lr_save_offset = ((void *) &dummy.lr_save - (void *) &dummy);
  97
  98           back_chain_loc = DWARF_LOC (c->dwarf.cfa + back_chain_offset, 0);
  99
 100           if ((ret =
 101                dwarf_get (&c->dwarf, back_chain_loc, &c->dwarf.cfa)) < 0)
 102             {
 103               Debug (2,
 104                  "Unable to retrieve CFA from back chain in stack frame - %d\n",
 105                  ret);
 106               return ret;
 107             }
 108           if (c->dwarf.cfa == 0)
 109             /* Unless the cursor or stack is corrupt or uninitialized we've most
 110                likely hit the top of the stack */
 111             return 0;
 112
 113           lr_save_loc = DWARF_LOC (c->dwarf.cfa + lr_save_offset, 0);
 114
 115           if ((ret = dwarf_get (&c->dwarf, lr_save_loc, &c->dwarf.ip)) < 0)
 116             {
 117               Debug (2,
 118                  "Unable to retrieve IP from lr save in stack frame - %d\n",
 119                  ret);
 120               return ret;
 121             }
 122           ret = 1;
 123         }
 124       else
 125         {
 126           /* Find the sigcontext record by taking the CFA and adjusting by
 127              the dummy signal frame size.
 128
 129              Note that there isn't any way to determined if SA_SIGINFO was
 130              set in the sa_flags parameter to sigaction when the signal
 131              handler was established.  If it was not set, the ucontext
 132              record is not required to be on the stack, in which case the
 133              following code will likely cause a seg fault or other crash
 134              condition.  */
 135
 136           unw_word_t ucontext = c->dwarf.cfa + __SIGNAL_FRAMESIZE;
 137
 138           Debug (1, "signal frame, skip over trampoline\n");
 139
 140           c->sigcontext_format = PPC_SCF_LINUX_RT_SIGFRAME;
 141           c->sigcontext_addr = ucontext;
 142
 143           sp_loc = DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R1, 0);
 144           ip_loc = DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_NIP, 0);
 145
 146           ret = dwarf_get (&c->dwarf, sp_loc, &c->dwarf.cfa);
 147           if (ret < 0)
 148             {
 149               Debug (2, "returning %d\n", ret);
 150               return ret;
 151             }
 152           ret = dwarf_get (&c->dwarf, ip_loc, &c->dwarf.ip);
 153           if (ret < 0)
 154             {
 155               Debug (2, "returning %d\n", ret);
 156               return ret;
 157             }
 158
 159           /* Instead of just restoring the non-volatile registers, do all
 160              of the registers for now.  This will incur a performance hit,
 161              but it's rare enough not to cause too much of a problem, and
 162              might be useful in some cases.  */
 163           c->dwarf.loc[UNW_PPC64_R0] =
 164             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R0, 0);
 165           c->dwarf.loc[UNW_PPC64_R1] =
 166             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R1, 0);
 167           c->dwarf.loc[UNW_PPC64_R2] =
 168             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R2, 0);
 169           c->dwarf.loc[UNW_PPC64_R3] =
 170             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R3, 0);
 171           c->dwarf.loc[UNW_PPC64_R4] =
 172             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R4, 0);
 173           c->dwarf.loc[UNW_PPC64_R5] =
 174             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R5, 0);
 175           c->dwarf.loc[UNW_PPC64_R6] =
 176             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R6, 0);
 177           c->dwarf.loc[UNW_PPC64_R7] =
 178             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R7, 0);
 179           c->dwarf.loc[UNW_PPC64_R8] =
 180             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R8, 0);
 181           c->dwarf.loc[UNW_PPC64_R9] =
 182             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R9, 0);
 183           c->dwarf.loc[UNW_PPC64_R10] =
 184             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R10, 0);
 185           c->dwarf.loc[UNW_PPC64_R11] =
 186             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R11, 0);
 187           c->dwarf.loc[UNW_PPC64_R12] =
 188             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R12, 0);
 189           c->dwarf.loc[UNW_PPC64_R13] =
 190             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R13, 0);
 191           c->dwarf.loc[UNW_PPC64_R14] =
 192             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R14, 0);
 193           c->dwarf.loc[UNW_PPC64_R15] =
 194             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R15, 0);
 195           c->dwarf.loc[UNW_PPC64_R16] =
 196             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R16, 0);
 197           c->dwarf.loc[UNW_PPC64_R17] =
 198             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R17, 0);
 199           c->dwarf.loc[UNW_PPC64_R18] =
 200             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R18, 0);
 201           c->dwarf.loc[UNW_PPC64_R19] =
 202             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R19, 0);
 203           c->dwarf.loc[UNW_PPC64_R20] =
 204             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R20, 0);
 205           c->dwarf.loc[UNW_PPC64_R21] =
 206             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R21, 0);
 207           c->dwarf.loc[UNW_PPC64_R22] =
 208             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R22, 0);
 209           c->dwarf.loc[UNW_PPC64_R23] =
 210             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R23, 0);
 211           c->dwarf.loc[UNW_PPC64_R24] =
 212             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R24, 0);
 213           c->dwarf.loc[UNW_PPC64_R25] =
 214             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R25, 0);
 215           c->dwarf.loc[UNW_PPC64_R26] =
 216             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R26, 0);
 217           c->dwarf.loc[UNW_PPC64_R27] =
 218             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R27, 0);
 219           c->dwarf.loc[UNW_PPC64_R28] =
 220             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R28, 0);
 221           c->dwarf.loc[UNW_PPC64_R29] =
 222             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R29, 0);
 223           c->dwarf.loc[UNW_PPC64_R30] =
 224             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R30, 0);
 225           c->dwarf.loc[UNW_PPC64_R31] =
 226             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_R31, 0);
 227
 228           c->dwarf.loc[UNW_PPC64_LR] =
 229             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_LINK, 0);
 230           c->dwarf.loc[UNW_PPC64_CTR] =
 231             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_CTR, 0);
 232           /* This CR0 assignment is probably wrong.  There are 8 dwarf columns
 233              assigned to the CR registers, but only one CR register in the
 234              mcontext structure */
 235           c->dwarf.loc[UNW_PPC64_CR0] =
 236             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_CCR, 0);
 237           c->dwarf.loc[UNW_PPC64_XER] =
 238             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_XER, 0);
 239           c->dwarf.loc[UNW_PPC64_NIP] =
 240             DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_NIP, 0);
 241
 242           /* TODO: Is there a way of obtaining the value of the
 243              pseudo frame pointer (which is sp + some fixed offset, I
 244              assume), based on the contents of the ucontext record
 245              structure?  For now, set this loc to null. */
 246           c->dwarf.loc[UNW_PPC64_FRAME_POINTER] = DWARF_NULL_LOC;
 247
 248           c->dwarf.loc[UNW_PPC64_F0] =
 249             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R0, 0);
 250           c->dwarf.loc[UNW_PPC64_F1] =
 251             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R1, 0);
 252           c->dwarf.loc[UNW_PPC64_F2] =
 253             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R2, 0);
 254           c->dwarf.loc[UNW_PPC64_F3] =
 255             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R3, 0);
 256           c->dwarf.loc[UNW_PPC64_F4] =
 257             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R4, 0);
 258           c->dwarf.loc[UNW_PPC64_F5] =
 259             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R5, 0);
 260           c->dwarf.loc[UNW_PPC64_F6] =
 261             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R6, 0);
 262           c->dwarf.loc[UNW_PPC64_F7] =
 263             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R7, 0);
 264           c->dwarf.loc[UNW_PPC64_F8] =
 265             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R8, 0);
 266           c->dwarf.loc[UNW_PPC64_F9] =
 267             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R9, 0);
 268           c->dwarf.loc[UNW_PPC64_F10] =
 269             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R10, 0);
 270           c->dwarf.loc[UNW_PPC64_F11] =
 271             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R11, 0);
 272           c->dwarf.loc[UNW_PPC64_F12] =
 273             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R12, 0);
 274           c->dwarf.loc[UNW_PPC64_F13] =
 275             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R13, 0);
 276           c->dwarf.loc[UNW_PPC64_F14] =
 277             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R14, 0);
 278           c->dwarf.loc[UNW_PPC64_F15] =
 279             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R15, 0);
 280           c->dwarf.loc[UNW_PPC64_F16] =
 281             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R16, 0);
 282           c->dwarf.loc[UNW_PPC64_F17] =
 283             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R17, 0);
 284           c->dwarf.loc[UNW_PPC64_F18] =
 285             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R18, 0);
 286           c->dwarf.loc[UNW_PPC64_F19] =
 287             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R19, 0);
 288           c->dwarf.loc[UNW_PPC64_F20] =
 289             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R20, 0);
 290           c->dwarf.loc[UNW_PPC64_F21] =
 291             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R21, 0);
 292           c->dwarf.loc[UNW_PPC64_F22] =
 293             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R22, 0);
 294           c->dwarf.loc[UNW_PPC64_F23] =
 295             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R23, 0);
 296           c->dwarf.loc[UNW_PPC64_F24] =
 297             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R24, 0);
 298           c->dwarf.loc[UNW_PPC64_F25] =
 299             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R25, 0);
 300           c->dwarf.loc[UNW_PPC64_F26] =
 301             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R26, 0);
 302           c->dwarf.loc[UNW_PPC64_F27] =
 303             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R27, 0);
 304           c->dwarf.loc[UNW_PPC64_F28] =
 305             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R28, 0);
 306           c->dwarf.loc[UNW_PPC64_F29] =
 307             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R29, 0);
 308           c->dwarf.loc[UNW_PPC64_F30] =
 309             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R30, 0);
 310           c->dwarf.loc[UNW_PPC64_F31] =
 311             DWARF_LOC (ucontext + UC_MCONTEXT_FREGS_R31, 0);
 312           /* Note that there is no .eh_section register column for the
 313              FPSCR register.  I don't know why this is.  */
 314
 315           v_regs_loc = DWARF_LOC (ucontext + UC_MCONTEXT_V_REGS, 0);
 316           ret = dwarf_get (&c->dwarf, v_regs_loc, &v_regs_ptr);
 317           if (ret < 0)
 318             {
 319               Debug (2, "returning %d\n", ret);
 320               return ret;
 321             }
 322           if (v_regs_ptr != 0)
 323             {
 324               /* The v_regs_ptr is not null.  Set all of the AltiVec locs */
 325
 326               c->dwarf.loc[UNW_PPC64_V0] =
 327                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R0, 0);
 328               c->dwarf.loc[UNW_PPC64_V1] =
 329                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R1, 0);
 330               c->dwarf.loc[UNW_PPC64_V2] =
 331                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R2, 0);
 332               c->dwarf.loc[UNW_PPC64_V3] =
 333                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R3, 0);
 334               c->dwarf.loc[UNW_PPC64_V4] =
 335                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R4, 0);
 336               c->dwarf.loc[UNW_PPC64_V5] =
 337                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R5, 0);
 338               c->dwarf.loc[UNW_PPC64_V6] =
 339                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R6, 0);
 340               c->dwarf.loc[UNW_PPC64_V7] =
 341                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R7, 0);
 342               c->dwarf.loc[UNW_PPC64_V8] =
 343                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R8, 0);
 344               c->dwarf.loc[UNW_PPC64_V9] =
 345                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R9, 0);
 346               c->dwarf.loc[UNW_PPC64_V10] =
 347                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R10, 0);
 348               c->dwarf.loc[UNW_PPC64_V11] =
 349                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R11, 0);
 350               c->dwarf.loc[UNW_PPC64_V12] =
 351                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R12, 0);
 352               c->dwarf.loc[UNW_PPC64_V13] =
 353                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R13, 0);
 354               c->dwarf.loc[UNW_PPC64_V14] =
 355                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R14, 0);
 356               c->dwarf.loc[UNW_PPC64_V15] =
 357                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R15, 0);
 358               c->dwarf.loc[UNW_PPC64_V16] =
 359                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R16, 0);
 360               c->dwarf.loc[UNW_PPC64_V17] =
 361                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R17, 0);
 362               c->dwarf.loc[UNW_PPC64_V18] =
 363                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R18, 0);
 364               c->dwarf.loc[UNW_PPC64_V19] =
 365                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R19, 0);
 366               c->dwarf.loc[UNW_PPC64_V20] =
 367                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R20, 0);
 368               c->dwarf.loc[UNW_PPC64_V21] =
 369                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R21, 0);
 370               c->dwarf.loc[UNW_PPC64_V22] =
 371                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R22, 0);
 372               c->dwarf.loc[UNW_PPC64_V23] =
 373                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R23, 0);
 374               c->dwarf.loc[UNW_PPC64_V24] =
 375                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R24, 0);
 376               c->dwarf.loc[UNW_PPC64_V25] =
 377                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R25, 0);
 378               c->dwarf.loc[UNW_PPC64_V26] =
 379                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R26, 0);
 380               c->dwarf.loc[UNW_PPC64_V27] =
 381                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R27, 0);
 382               c->dwarf.loc[UNW_PPC64_V28] =
 383                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R28, 0);
 384               c->dwarf.loc[UNW_PPC64_V29] =
 385                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R29, 0);
 386               c->dwarf.loc[UNW_PPC64_V30] =
 387                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R30, 0);
 388               c->dwarf.loc[UNW_PPC64_V31] =
 389                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_R31, 0);
 390               c->dwarf.loc[UNW_PPC64_VRSAVE] =
 391                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_VRSAVE, 0);
 392               c->dwarf.loc[UNW_PPC64_VSCR] =
 393                 DWARF_LOC (v_regs_ptr + UC_MCONTEXT_VREGS_VSCR, 0);
 394             }
 395           else
 396             {
 397               c->dwarf.loc[UNW_PPC64_V0] = DWARF_NULL_LOC;
 398               c->dwarf.loc[UNW_PPC64_V1] = DWARF_NULL_LOC;
 399               c->dwarf.loc[UNW_PPC64_V2] = DWARF_NULL_LOC;
 400               c->dwarf.loc[UNW_PPC64_V3] = DWARF_NULL_LOC;
 401               c->dwarf.loc[UNW_PPC64_V4] = DWARF_NULL_LOC;
 402               c->dwarf.loc[UNW_PPC64_V5] = DWARF_NULL_LOC;
 403               c->dwarf.loc[UNW_PPC64_V6] = DWARF_NULL_LOC;
 404               c->dwarf.loc[UNW_PPC64_V7] = DWARF_NULL_LOC;
 405               c->dwarf.loc[UNW_PPC64_V8] = DWARF_NULL_LOC;
 406               c->dwarf.loc[UNW_PPC64_V9] = DWARF_NULL_LOC;
 407               c->dwarf.loc[UNW_PPC64_V10] = DWARF_NULL_LOC;
 408               c->dwarf.loc[UNW_PPC64_V11] = DWARF_NULL_LOC;
 409               c->dwarf.loc[UNW_PPC64_V12] = DWARF_NULL_LOC;
 410               c->dwarf.loc[UNW_PPC64_V13] = DWARF_NULL_LOC;
 411               c->dwarf.loc[UNW_PPC64_V14] = DWARF_NULL_LOC;
 412               c->dwarf.loc[UNW_PPC64_V15] = DWARF_NULL_LOC;
 413               c->dwarf.loc[UNW_PPC64_V16] = DWARF_NULL_LOC;
 414               c->dwarf.loc[UNW_PPC64_V17] = DWARF_NULL_LOC;
 415               c->dwarf.loc[UNW_PPC64_V18] = DWARF_NULL_LOC;
 416               c->dwarf.loc[UNW_PPC64_V19] = DWARF_NULL_LOC;
 417               c->dwarf.loc[UNW_PPC64_V20] = DWARF_NULL_LOC;
 418               c->dwarf.loc[UNW_PPC64_V21] = DWARF_NULL_LOC;
 419               c->dwarf.loc[UNW_PPC64_V22] = DWARF_NULL_LOC;
 420               c->dwarf.loc[UNW_PPC64_V23] = DWARF_NULL_LOC;
 421               c->dwarf.loc[UNW_PPC64_V24] = DWARF_NULL_LOC;
 422               c->dwarf.loc[UNW_PPC64_V25] = DWARF_NULL_LOC;
 423               c->dwarf.loc[UNW_PPC64_V26] = DWARF_NULL_LOC;
 424               c->dwarf.loc[UNW_PPC64_V27] = DWARF_NULL_LOC;
 425               c->dwarf.loc[UNW_PPC64_V28] = DWARF_NULL_LOC;
 426               c->dwarf.loc[UNW_PPC64_V29] = DWARF_NULL_LOC;
 427               c->dwarf.loc[UNW_PPC64_V30] = DWARF_NULL_LOC;
 428               c->dwarf.loc[UNW_PPC64_V31] = DWARF_NULL_LOC;
 429               c->dwarf.loc[UNW_PPC64_VRSAVE] = DWARF_NULL_LOC;
 430               c->dwarf.loc[UNW_PPC64_VSCR] = DWARF_NULL_LOC;
 431             }
 432           ret = 1;
 433         }
 434     }
 435   return ret;
 436 }