gdb/spu-linux-nat.c

   1 /* SPU native-dependent code for GDB, the GNU debugger.
   2    Copyright (C) 2006-2013 Free Software Foundation, Inc.
   3
   4    Contributed by Ulrich Weigand <uweigand@de.ibm.com>.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "gdbcore.h"
  23 #include "gdb_string.h"
  24 #include "target.h"
  25 #include "inferior.h"
  26 #include "inf-child.h"
  27 #include "inf-ptrace.h"
  28 #include "regcache.h"
  29 #include "symfile.h"
  30 #include "gdb_wait.h"
  31 #include "gdbthread.h"
  32 #include "gdb_bfd.h"
  33
  34 #include <sys/ptrace.h>
  35 #include <asm/ptrace.h>
  36 #include <sys/types.h>
  37
  38 #include "spu-tdep.h"
  39
  40 /* PPU side system calls.  */
  41 #define INSTR_SC        0x44000002
  42 #define NR_spu_run      0x0116
  43
  44
  45 /* Fetch PPU register REGNO.  */
  46 static ULONGEST
  47 fetch_ppc_register (int regno)
  48 {
  49   PTRACE_TYPE_RET res;
  50
  51   int tid = ptid_get_lwp (inferior_ptid);
  52   if (tid == 0)
  53     tid = ptid_get_pid (inferior_ptid);
  54
  55 #ifndef __powerpc64__
  56   /* If running as a 32-bit process on a 64-bit system, we attempt
  57      to get the full 64-bit register content of the target process.
  58      If the PPC special ptrace call fails, we're on a 32-bit system;
  59      just fall through to the regular ptrace call in that case.  */
  60   {
  61     gdb_byte buf[8];
  62
  63     errno = 0;
  64     ptrace (PPC_PTRACE_PEEKUSR_3264, tid,
  65             (PTRACE_TYPE_ARG3) (regno * 8), buf);
  66     if (errno == 0)
  67       ptrace (PPC_PTRACE_PEEKUSR_3264, tid,
  68               (PTRACE_TYPE_ARG3) (regno * 8 + 4), buf + 4);
  69     if (errno == 0)
  70       return (ULONGEST) *(uint64_t *)buf;
  71   }
  72 #endif
  73
  74   errno = 0;
  75   res = ptrace (PT_READ_U, tid,
  76                 (PTRACE_TYPE_ARG3) (regno * sizeof (PTRACE_TYPE_RET)), 0);
  77   if (errno != 0)
  78     {
  79       char mess[128];
  80       xsnprintf (mess, sizeof mess, "reading PPC register #%d", regno);
  81       perror_with_name (_(mess));
  82     }
  83
  84   return (ULONGEST) (unsigned long) res;
  85 }
  86
  87 /* Fetch WORD from PPU memory at (aligned) MEMADDR in thread TID.  */
  88 static int
  89 fetch_ppc_memory_1 (int tid, ULONGEST memaddr, PTRACE_TYPE_RET *word)
  90 {
  91   errno = 0;
  92
  93 #ifndef __powerpc64__
  94   if (memaddr >> 32)
  95     {
  96       uint64_t addr_8 = (uint64_t) memaddr;
  97       ptrace (PPC_PTRACE_PEEKTEXT_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);
  98     }
  99   else
 100 #endif
 101     *word = ptrace (PT_READ_I, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, 0);
 102
 103   return errno;
 104 }
 105
 106 /* Store WORD into PPU memory at (aligned) MEMADDR in thread TID.  */
 107 static int
 108 store_ppc_memory_1 (int tid, ULONGEST memaddr, PTRACE_TYPE_RET word)
 109 {
 110   errno = 0;
 111
 112 #ifndef __powerpc64__
 113   if (memaddr >> 32)
 114     {
 115       uint64_t addr_8 = (uint64_t) memaddr;
 116       ptrace (PPC_PTRACE_POKEDATA_3264, tid, (PTRACE_TYPE_ARG3) &addr_8, word);
 117     }
 118   else
 119 #endif
 120     ptrace (PT_WRITE_D, tid, (PTRACE_TYPE_ARG3) (size_t) memaddr, word);
 121
 122   return errno;
 123 }
 124
 125 /* Fetch LEN bytes of PPU memory at MEMADDR to MYADDR.  */
 126 static int
 127 fetch_ppc_memory (ULONGEST memaddr, gdb_byte *myaddr, int len)
 128 {
 129   int i, ret;
 130
 131   ULONGEST addr = memaddr & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 132   int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)
 133                / sizeof (PTRACE_TYPE_RET));
 134   PTRACE_TYPE_RET *buffer;
 135
 136   int tid = ptid_get_lwp (inferior_ptid);
 137   if (tid == 0)
 138     tid = ptid_get_pid (inferior_ptid);
 139
 140   buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));
 141   for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))
 142     {
 143       ret = fetch_ppc_memory_1 (tid, addr, &buffer[i]);
 144       if (ret)
 145         return ret;
 146     }
 147
 148   memcpy (myaddr,
 149           (char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),
 150           len);
 151
 152   return 0;
 153 }
 154
 155 /* Store LEN bytes from MYADDR to PPU memory at MEMADDR.  */
 156 static int
 157 store_ppc_memory (ULONGEST memaddr, const gdb_byte *myaddr, int len)
 158 {
 159   int i, ret;
 160
 161   ULONGEST addr = memaddr & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 162   int count = ((((memaddr + len) - addr) + sizeof (PTRACE_TYPE_RET) - 1)
 163                / sizeof (PTRACE_TYPE_RET));
 164   PTRACE_TYPE_RET *buffer;
 165
 166   int tid = ptid_get_lwp (inferior_ptid);
 167   if (tid == 0)
 168     tid = ptid_get_pid (inferior_ptid);
 169
 170   buffer = (PTRACE_TYPE_RET *) alloca (count * sizeof (PTRACE_TYPE_RET));
 171
 172   if (addr != memaddr || len < (int) sizeof (PTRACE_TYPE_RET))
 173     {
 174       ret = fetch_ppc_memory_1 (tid, addr, &buffer[0]);
 175       if (ret)
 176         return ret;
 177     }
 178
 179   if (count > 1)
 180     {
 181       ret = fetch_ppc_memory_1 (tid, addr + (count - 1)
 182                                                * sizeof (PTRACE_TYPE_RET),
 183                                 &buffer[count - 1]);
 184       if (ret)
 185         return ret;
 186     }
 187
 188   memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_TYPE_RET) - 1)),
 189           myaddr, len);
 190
 191   for (i = 0; i < count; i++, addr += sizeof (PTRACE_TYPE_RET))
 192     {
 193       ret = store_ppc_memory_1 (tid, addr, buffer[i]);
 194       if (ret)
 195         return ret;
 196     }
 197
 198   return 0;
 199 }
 200
 201
 202 /* If the PPU thread is currently stopped on a spu_run system call,
 203    return to FD and ADDR the file handle and NPC parameter address
 204    used with the system call.  Return non-zero if successful.  */
 205 static int
 206 parse_spufs_run (int *fd, ULONGEST *addr)
 207 {
 208   enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
 209   gdb_byte buf[4];
 210   ULONGEST pc = fetch_ppc_register (32);  /* nip */
 211
 212   /* Fetch instruction preceding current NIP.  */
 213   if (fetch_ppc_memory (pc-4, buf, 4) != 0)
 214     return 0;
 215   /* It should be a "sc" instruction.  */
 216   if (extract_unsigned_integer (buf, 4, byte_order) != INSTR_SC)
 217     return 0;
 218   /* System call number should be NR_spu_run.  */
 219   if (fetch_ppc_register (0) != NR_spu_run)
 220     return 0;
 221
 222   /* Register 3 contains fd, register 4 the NPC param pointer.  */
 223   *fd = fetch_ppc_register (34);  /* orig_gpr3 */
 224   *addr = fetch_ppc_register (4);
 225   return 1;
 226 }
 227
 228
 229 /* Copy LEN bytes at OFFSET in spufs file ANNEX into/from READBUF or WRITEBUF,
 230    using the /proc file system.  */
 231 static LONGEST
 232 spu_proc_xfer_spu (const char *annex, gdb_byte *readbuf,
 233                    const gdb_byte *writebuf,
 234                    ULONGEST offset, LONGEST len)
 235 {
 236   char buf[128];
 237   int fd = 0;
 238   int ret = -1;
 239   int pid = ptid_get_pid (inferior_ptid);
 240
 241   if (!annex)
 242     return 0;
 243
 244   xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
 245   fd = open (buf, writebuf? O_WRONLY : O_RDONLY);
 246   if (fd <= 0)
 247     return -1;
 248
 249   if (offset != 0
 250       && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
 251     {
 252       close (fd);
 253       return 0;
 254     }
 255
 256   if (writebuf)
 257     ret = write (fd, writebuf, (size_t) len);
 258   else if (readbuf)
 259     ret = read (fd, readbuf, (size_t) len);
 260
 261   close (fd);
 262   return ret;
 263 }
 264
 265
 266 /* Inferior memory should contain an SPE executable image at location ADDR.
 267    Allocate a BFD representing that executable.  Return NULL on error.  */
 268
 269 static void *
 270 spu_bfd_iovec_open (struct bfd *nbfd, void *open_closure)
 271 {
 272   return open_closure;
 273 }
 274
 275 static int
 276 spu_bfd_iovec_close (struct bfd *nbfd, void *stream)
 277 {
 278   xfree (stream);
 279
 280   /* Zero means success.  */
 281   return 0;
 282 }
 283
 284 static file_ptr
 285 spu_bfd_iovec_pread (struct bfd *abfd, void *stream, void *buf,
 286                      file_ptr nbytes, file_ptr offset)
 287 {
 288   ULONGEST addr = *(ULONGEST *)stream;
 289
 290   if (fetch_ppc_memory (addr + offset, buf, nbytes) != 0)
 291     {
 292       bfd_set_error (bfd_error_invalid_operation);
 293       return -1;
 294     }
 295
 296   return nbytes;
 297 }
 298
 299 static int
 300 spu_bfd_iovec_stat (struct bfd *abfd, void *stream, struct stat *sb)
 301 {
 302   /* We don't have an easy way of finding the size of embedded spu
 303      images.  We could parse the in-memory ELF header and section
 304      table to find the extent of the last section but that seems
 305      pointless when the size is needed only for checks of other
 306      parsed values in dbxread.c.  */
 307   sb->st_size = INT_MAX;
 308   return 0;
 309 }
 310
 311 static bfd *
 312 spu_bfd_open (ULONGEST addr)
 313 {
 314   struct bfd *nbfd;
 315   asection *spu_name;
 316
 317   ULONGEST *open_closure = xmalloc (sizeof (ULONGEST));
 318   *open_closure = addr;
 319
 320   nbfd = gdb_bfd_openr_iovec ("<in-memory>", "elf32-spu",
 321                               spu_bfd_iovec_open, open_closure,
 322                               spu_bfd_iovec_pread, spu_bfd_iovec_close,
 323                               spu_bfd_iovec_stat);
 324   if (!nbfd)
 325     return NULL;
 326
 327   if (!bfd_check_format (nbfd, bfd_object))
 328     {
 329       gdb_bfd_unref (nbfd);
 330       return NULL;
 331     }
 332
 333   /* Retrieve SPU name note and update BFD name.  */
 334   spu_name = bfd_get_section_by_name (nbfd, ".note.spu_name");
 335   if (spu_name)
 336     {
 337       int sect_size = bfd_section_size (nbfd, spu_name);
 338       if (sect_size > 20)
 339         {
 340           char *buf = alloca (sect_size - 20 + 1);
 341           bfd_get_section_contents (nbfd, spu_name, buf, 20, sect_size - 20);
 342           buf[sect_size - 20] = '\0';
 343
 344           xfree ((char *)nbfd->filename);
 345           nbfd->filename = xstrdup (buf);
 346         }
 347     }
 348
 349   return nbfd;
 350 }
 351
 352 /* INFERIOR_FD is a file handle passed by the inferior to the
 353    spu_run system call.  Assuming the SPE context was allocated
 354    by the libspe library, try to retrieve the main SPE executable
 355    file from its copy within the target process.  */
 356 static void
 357 spu_symbol_file_add_from_memory (int inferior_fd)
 358 {
 359   ULONGEST addr;
 360   struct bfd *nbfd;
 361
 362   char id[128];
 363   char annex[32];
 364   int len;
 365
 366   /* Read object ID.  */
 367   xsnprintf (annex, sizeof annex, "%d/object-id", inferior_fd);
 368   len = spu_proc_xfer_spu (annex, id, NULL, 0, sizeof id);
 369   if (len <= 0 || len >= sizeof id)
 370     return;
 371   id[len] = 0;
 372   addr = strtoulst (id, NULL, 16);
 373   if (!addr)
 374     return;
 375
 376   /* Open BFD representing SPE executable and read its symbols.  */
 377   nbfd = spu_bfd_open (addr);
 378   if (nbfd)
 379     {
 380       struct cleanup *cleanup = make_cleanup_bfd_unref (nbfd);
 381
 382       symbol_file_add_from_bfd (nbfd, SYMFILE_VERBOSE | SYMFILE_MAINLINE,
 383                                 NULL, 0, NULL);
 384       do_cleanups (cleanup);
 385     }
 386 }
 387
 388
 389 /* Override the post_startup_inferior routine to continue running
 390    the inferior until the first spu_run system call.  */
 391 static void
 392 spu_child_post_startup_inferior (ptid_t ptid)
 393 {
 394   int fd;
 395   ULONGEST addr;
 396
 397   int tid = ptid_get_lwp (ptid);
 398   if (tid == 0)
 399     tid = ptid_get_pid (ptid);
 400
 401   while (!parse_spufs_run (&fd, &addr))
 402     {
 403       ptrace (PT_SYSCALL, tid, (PTRACE_TYPE_ARG3) 0, 0);
 404       waitpid (tid, NULL, __WALL | __WNOTHREAD);
 405     }
 406 }
 407
 408 /* Override the post_attach routine to try load the SPE executable
 409    file image from its copy inside the target process.  */
 410 static void
 411 spu_child_post_attach (int pid)
 412 {
 413   int fd;
 414   ULONGEST addr;
 415
 416   /* Like child_post_startup_inferior, if we happened to attach to
 417      the inferior while it wasn't currently in spu_run, continue
 418      running it until we get back there.  */
 419   while (!parse_spufs_run (&fd, &addr))
 420     {
 421       ptrace (PT_SYSCALL, pid, (PTRACE_TYPE_ARG3) 0, 0);
 422       waitpid (pid, NULL, __WALL | __WNOTHREAD);
 423     }
 424
 425   /* If the user has not provided an executable file, try to extract
 426      the image from inside the target process.  */
 427   if (!get_exec_file (0))
 428     spu_symbol_file_add_from_memory (fd);
 429 }
 430
 431 /* Wait for child PTID to do something.  Return id of the child,
 432    minus_one_ptid in case of error; store status into *OURSTATUS.  */
 433 static ptid_t
 434 spu_child_wait (struct target_ops *ops,
 435                 ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 436 {
 437   int save_errno;
 438   int status;
 439   pid_t pid;
 440
 441   do
 442     {
 443       set_sigint_trap ();       /* Causes SIGINT to be passed on to the
 444                                    attached process.  */
 445
 446       pid = waitpid (ptid_get_pid (ptid), &status, 0);
 447       if (pid == -1 && errno == ECHILD)
 448         /* Try again with __WCLONE to check cloned processes.  */
 449         pid = waitpid (ptid_get_pid (ptid), &status, __WCLONE);
 450
 451       save_errno = errno;
 452
 453       /* Make sure we don't report an event for the exit of the
 454          original program, if we've detached from it.  */
 455       if (pid != -1 && !WIFSTOPPED (status)
 456           && pid != ptid_get_pid (inferior_ptid))
 457         {
 458           pid = -1;
 459           save_errno = EINTR;
 460         }
 461
 462       clear_sigint_trap ();
 463     }
 464   while (pid == -1 && save_errno == EINTR);
 465
 466   if (pid == -1)
 467     {
 468       warning (_("Child process unexpectedly missing: %s"),
 469                safe_strerror (save_errno));
 470
 471       /* Claim it exited with unknown signal.  */
 472       ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 473       ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
 474       return inferior_ptid;
 475     }
 476
 477   store_waitstatus (ourstatus, status);
 478   return pid_to_ptid (pid);
 479 }
 480
 481 /* Override the fetch_inferior_register routine.  */
 482 static void
 483 spu_fetch_inferior_registers (struct target_ops *ops,
 484                               struct regcache *regcache, int regno)
 485 {
 486   int fd;
 487   ULONGEST addr;
 488
 489   /* We must be stopped on a spu_run system call.  */
 490   if (!parse_spufs_run (&fd, &addr))
 491     return;
 492
 493   /* The ID register holds the spufs file handle.  */
 494   if (regno == -1 || regno == SPU_ID_REGNUM)
 495     {
 496       struct gdbarch *gdbarch = get_regcache_arch (regcache);
 497       enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 498       gdb_byte buf[4];
 499       store_unsigned_integer (buf, 4, byte_order, fd);
 500       regcache_raw_supply (regcache, SPU_ID_REGNUM, buf);
 501     }
 502
 503   /* The NPC register is found at ADDR.  */
 504   if (regno == -1 || regno == SPU_PC_REGNUM)
 505     {
 506       gdb_byte buf[4];
 507       if (fetch_ppc_memory (addr, buf, 4) == 0)
 508         regcache_raw_supply (regcache, SPU_PC_REGNUM, buf);
 509     }
 510
 511   /* The GPRs are found in the "regs" spufs file.  */
 512   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_GPRS))
 513     {
 514       gdb_byte buf[16 * SPU_NUM_GPRS];
 515       char annex[32];
 516       int i;
 517
 518       xsnprintf (annex, sizeof annex, "%d/regs", fd);
 519       if (spu_proc_xfer_spu (annex, buf, NULL, 0, sizeof buf) == sizeof buf)
 520         for (i = 0; i < SPU_NUM_GPRS; i++)
 521           regcache_raw_supply (regcache, i, buf + i*16);
 522     }
 523 }
 524
 525 /* Override the store_inferior_register routine.  */
 526 static void
 527 spu_store_inferior_registers (struct target_ops *ops,
 528                               struct regcache *regcache, int regno)
 529 {
 530   int fd;
 531   ULONGEST addr;
 532
 533   /* We must be stopped on a spu_run system call.  */
 534   if (!parse_spufs_run (&fd, &addr))
 535     return;
 536
 537   /* The NPC register is found at ADDR.  */
 538   if (regno == -1 || regno == SPU_PC_REGNUM)
 539     {
 540       gdb_byte buf[4];
 541       regcache_raw_collect (regcache, SPU_PC_REGNUM, buf);
 542       store_ppc_memory (addr, buf, 4);
 543     }
 544
 545   /* The GPRs are found in the "regs" spufs file.  */
 546   if (regno == -1 || (regno >= 0 && regno < SPU_NUM_GPRS))
 547     {
 548       gdb_byte buf[16 * SPU_NUM_GPRS];
 549       char annex[32];
 550       int i;
 551
 552       for (i = 0; i < SPU_NUM_GPRS; i++)
 553         regcache_raw_collect (regcache, i, buf + i*16);
 554
 555       xsnprintf (annex, sizeof annex, "%d/regs", fd);
 556       spu_proc_xfer_spu (annex, NULL, buf, 0, sizeof buf);
 557     }
 558 }
 559
 560 /* Override the to_xfer_partial routine.  */
 561 static LONGEST
 562 spu_xfer_partial (struct target_ops *ops,
 563                   enum target_object object, const char *annex,
 564                   gdb_byte *readbuf, const gdb_byte *writebuf,
 565                   ULONGEST offset, LONGEST len)
 566 {
 567   if (object == TARGET_OBJECT_SPU)
 568     return spu_proc_xfer_spu (annex, readbuf, writebuf, offset, len);
 569
 570   if (object == TARGET_OBJECT_MEMORY)
 571     {
 572       int fd;
 573       ULONGEST addr;
 574       char mem_annex[32], lslr_annex[32];
 575       gdb_byte buf[32];
 576       ULONGEST lslr;
 577       LONGEST ret;
 578
 579       /* We must be stopped on a spu_run system call.  */
 580       if (!parse_spufs_run (&fd, &addr))
 581         return 0;
 582
 583       /* Use the "mem" spufs file to access SPU local store.  */
 584       xsnprintf (mem_annex, sizeof mem_annex, "%d/mem", fd);
 585       ret = spu_proc_xfer_spu (mem_annex, readbuf, writebuf, offset, len);
 586       if (ret > 0)
 587         return ret;
 588
 589       /* SPU local store access wraps the address around at the
 590          local store limit.  We emulate this here.  To avoid needing
 591          an extra access to retrieve the LSLR, we only do that after
 592          trying the original address first, and getting end-of-file.  */
 593       xsnprintf (lslr_annex, sizeof lslr_annex, "%d/lslr", fd);
 594       memset (buf, 0, sizeof buf);
 595       if (spu_proc_xfer_spu (lslr_annex, buf, NULL, 0, sizeof buf) <= 0)
 596         return ret;
 597
 598       lslr = strtoulst (buf, NULL, 16);
 599       return spu_proc_xfer_spu (mem_annex, readbuf, writebuf,
 600                                 offset & lslr, len);
 601     }
 602
 603   return -1;
 604 }
 605
 606 /* Override the to_can_use_hw_breakpoint routine.  */
 607 static int
 608 spu_can_use_hw_breakpoint (int type, int cnt, int othertype)
 609 {
 610   return 0;
 611 }
 612
 613
 614 /* Initialize SPU native target.  */
 615 void
 616 _initialize_spu_nat (void)
 617 {
 618   /* Generic ptrace methods.  */
 619   struct target_ops *t;
 620   t = inf_ptrace_target ();
 621
 622   /* Add SPU methods.  */
 623   t->to_post_attach = spu_child_post_attach;
 624   t->to_post_startup_inferior = spu_child_post_startup_inferior;
 625   t->to_wait = spu_child_wait;
 626   t->to_fetch_registers = spu_fetch_inferior_registers;
 627   t->to_store_registers = spu_store_inferior_registers;
 628   t->to_xfer_partial = spu_xfer_partial;
 629   t->to_can_use_hw_breakpoint = spu_can_use_hw_breakpoint;
 630
 631   /* Register SPU target.  */
 632   add_target (t);
 633 }