gdb/solib-spu.c

   1 /* Cell SPU GNU/Linux support -- shared library handling.
   2    Copyright (C) 2009-2019 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 "solib-spu.h"
  23 #include "gdbcore.h"
  24 #include <sys/stat.h>
  25 #include "arch-utils.h"
  26 #include "bfd.h"
  27 #include "symtab.h"
  28 #include "solib.h"
  29 #include "solib-svr4.h"
  30 #include "solist.h"
  31 #include "inferior.h"
  32 #include "objfiles.h"
  33 #include "observable.h"
  34 #include "breakpoint.h"
  35 #include "gdbthread.h"
  36 #include "gdb_bfd.h"
  37
  38 #include "spu-tdep.h"
  39
  40 /* Highest SPE id (file handle) the inferior may have.  */
  41 #define MAX_SPE_FD 1024
  42
  43 /* Stand-alone SPE executable?  */
  44 #define spu_standalone_p() \
  45   (symfile_objfile && symfile_objfile->obfd \
  46    && bfd_get_arch (symfile_objfile->obfd) == bfd_arch_spu)
  47
  48
  49 /* Relocate main SPE executable.  */
  50 static void
  51 spu_relocate_main_executable (int spufs_fd)
  52 {
  53   struct section_offsets *new_offsets;
  54   int i;
  55
  56   if (symfile_objfile == NULL)
  57     return;
  58
  59   new_offsets = XALLOCAVEC (struct section_offsets,
  60                             symfile_objfile->num_sections);
  61
  62   for (i = 0; i < symfile_objfile->num_sections; i++)
  63     new_offsets->offsets[i] = SPUADDR (spufs_fd, 0);
  64
  65   objfile_relocate (symfile_objfile, new_offsets);
  66 }
  67
  68 /* When running a stand-alone SPE executable, we may need to skip one more
  69    exec event on startup, to get past the binfmt_misc loader.  */
  70 static void
  71 spu_skip_standalone_loader (void)
  72 {
  73   if (target_has_execution && !current_inferior ()->attach_flag)
  74     {
  75       struct target_waitstatus ws;
  76
  77       /* Only some kernels report an extra SIGTRAP with the binfmt_misc
  78          loader; others do not.  In addition, if we have attached to an
  79          already running inferior instead of starting a new one, we will
  80          not see the extra SIGTRAP -- and we cannot readily distinguish
  81          the two cases, in particular with the extended-remote target.
  82
  83          Thus we issue a single-step here.  If no extra SIGTRAP was pending,
  84          this will step past the first instruction of the stand-alone SPE
  85          executable loader, but we don't care about that.  */
  86
  87       inferior_thread ()->control.in_infcall = 1; /* Suppress MI messages.  */
  88
  89       target_resume (inferior_ptid, 1, GDB_SIGNAL_0);
  90       target_wait (minus_one_ptid, &ws, 0);
  91       set_executing (minus_one_ptid, 0);
  92
  93       inferior_thread ()->control.in_infcall = 0;
  94     }
  95 }
  96
  97 static const struct objfile_data *ocl_program_data_key;
  98
  99 /* Appends OpenCL programs to the list of `struct so_list' objects.  */
 100 static void
 101 append_ocl_sos (struct so_list **link_ptr)
 102 {
 103   CORE_ADDR *ocl_program_addr_base;
 104
 105   for (objfile *objfile : current_program_space->objfiles ())
 106     {
 107       ocl_program_addr_base
 108         = (CORE_ADDR *) objfile_data (objfile, ocl_program_data_key);
 109       if (ocl_program_addr_base != NULL)
 110         {
 111           enum bfd_endian byte_order = bfd_big_endian (objfile->obfd)?
 112                                          BFD_ENDIAN_BIG : BFD_ENDIAN_LITTLE;
 113           try
 114             {
 115               CORE_ADDR data =
 116                 read_memory_unsigned_integer (*ocl_program_addr_base,
 117                                               sizeof (CORE_ADDR),
 118                                               byte_order);
 119               if (data != 0x0)
 120                 {
 121                   struct so_list *newobj;
 122
 123                   /* Allocate so_list structure.  */
 124                   newobj = XCNEW (struct so_list);
 125
 126                   /* Encode FD and object ID in path name.  */
 127                   xsnprintf (newobj->so_name, sizeof newobj->so_name, "@%s <%d>",
 128                              hex_string (data),
 129                              SPUADDR_SPU (*ocl_program_addr_base));
 130                   strcpy (newobj->so_original_name, newobj->so_name);
 131
 132                   *link_ptr = newobj;
 133                   link_ptr = &newobj->next;
 134                 }
 135             }
 136           catch (const gdb_exception &ex)
 137             {
 138               /* Ignore memory errors.  */
 139               switch (ex.error)
 140                 {
 141                 case MEMORY_ERROR:
 142                   break;
 143                 default:
 144                   throw;
 145                   break;
 146                 }
 147             }
 148         }
 149     }
 150 }
 151
 152 /* Build a list of `struct so_list' objects describing the shared
 153    objects currently loaded in the inferior.  */
 154 static struct so_list *
 155 spu_current_sos (void)
 156 {
 157   enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
 158   struct so_list *head;
 159   struct so_list **link_ptr;
 160
 161   gdb_byte buf[MAX_SPE_FD * 4];
 162   int i, size;
 163
 164   /* First, retrieve the SVR4 shared library list.  */
 165   head = svr4_so_ops.current_sos ();
 166
 167   /* Append our libraries to the end of the list.  */
 168   for (link_ptr = &head; *link_ptr; link_ptr = &(*link_ptr)->next)
 169     ;
 170
 171   /* Determine list of SPU ids.  */
 172   size = target_read (current_top_target (), TARGET_OBJECT_SPU, NULL,
 173                       buf, 0, sizeof buf);
 174
 175   /* Do not add stand-alone SPE executable context as shared library,
 176      but relocate main SPE executable objfile.  */
 177   if (spu_standalone_p ())
 178     {
 179       if (size == 4)
 180         {
 181           int fd = extract_unsigned_integer (buf, 4, byte_order);
 182
 183           spu_relocate_main_executable (fd);
 184
 185           /* Re-enable breakpoints after main SPU context was established;
 186              see also comments in spu_solib_create_inferior_hook.  */
 187           enable_breakpoints_after_startup ();
 188         }
 189
 190       return head;
 191     }
 192
 193   /* Create an so_list entry for each SPU id.  */
 194   for (i = 0; i < size; i += 4)
 195     {
 196       int fd = extract_unsigned_integer (buf + i, 4, byte_order);
 197       struct so_list *newobj;
 198
 199       unsigned long long addr;
 200       char annex[32], id[100];
 201       int len;
 202
 203       /* Read object ID.  There's a race window where the inferior may have
 204          already created the SPE context, but not installed the object-id
 205          yet.  Skip such entries; we'll be back for them later.  */
 206       xsnprintf (annex, sizeof annex, "%d/object-id", fd);
 207       len = target_read (current_top_target (), TARGET_OBJECT_SPU, annex,
 208                          (gdb_byte *) id, 0, sizeof id);
 209       if (len <= 0 || len >= sizeof id)
 210         continue;
 211       id[len] = 0;
 212       if (sscanf (id, "0x%llx", &addr) != 1 || !addr)
 213         continue;
 214
 215       /* Allocate so_list structure.  */
 216       newobj = XCNEW (struct so_list);
 217
 218       /* Encode FD and object ID in path name.  Choose the name so as not
 219          to conflict with any (normal) SVR4 library path name.  */
 220       xsnprintf (newobj->so_name, sizeof newobj->so_name, "@%s <%d>",
 221                  hex_string (addr), fd);
 222       strcpy (newobj->so_original_name, newobj->so_name);
 223
 224       *link_ptr = newobj;
 225       link_ptr = &newobj->next;
 226     }
 227
 228   /* Append OpenCL sos.  */
 229   append_ocl_sos (link_ptr);
 230
 231   return head;
 232 }
 233
 234 /* Free so_list information.  */
 235 static void
 236 spu_free_so (struct so_list *so)
 237 {
 238   if (so->so_original_name[0] != '@')
 239     svr4_so_ops.free_so (so);
 240 }
 241
 242 /* Relocate section addresses.  */
 243 static void
 244 spu_relocate_section_addresses (struct so_list *so,
 245                                 struct target_section *sec)
 246 {
 247   if (so->so_original_name[0] != '@')
 248     svr4_so_ops.relocate_section_addresses (so, sec);
 249   else
 250     {
 251       unsigned long long addr;
 252       int fd;
 253
 254       /* Set addr_low/high to just LS offset for display.  */
 255       if (so->addr_low == 0 && so->addr_high == 0
 256           && strcmp (sec->the_bfd_section->name, ".text") == 0)
 257         {
 258           so->addr_low = sec->addr;
 259           so->addr_high = sec->endaddr;
 260         }
 261
 262       /* Decode object ID.  */
 263       if (sscanf (so->so_original_name, "@0x%llx <%d>", &addr, &fd) != 2)
 264         internal_error (__FILE__, __LINE__, "bad object ID");
 265
 266       sec->addr = SPUADDR (fd, sec->addr);
 267       sec->endaddr = SPUADDR (fd, sec->endaddr);
 268     }
 269 }
 270
 271
 272 /* Inferior memory should contain an SPE executable image at location ADDR.
 273    Allocate a BFD representing that executable.  Return NULL on error.  */
 274
 275 static void *
 276 spu_bfd_iovec_open (bfd *nbfd, void *open_closure)
 277 {
 278   return open_closure;
 279 }
 280
 281 static int
 282 spu_bfd_iovec_close (bfd *nbfd, void *stream)
 283 {
 284   xfree (stream);
 285
 286   /* Zero means success.  */
 287   return 0;
 288 }
 289
 290 static file_ptr
 291 spu_bfd_iovec_pread (bfd *abfd, void *stream, void *buf,
 292                      file_ptr nbytes, file_ptr offset)
 293 {
 294   CORE_ADDR addr = *(CORE_ADDR *)stream;
 295   int ret;
 296
 297   ret = target_read_memory (addr + offset, (gdb_byte *) buf, nbytes);
 298   if (ret != 0)
 299     {
 300       bfd_set_error (bfd_error_invalid_operation);
 301       return -1;
 302     }
 303
 304   return nbytes;
 305 }
 306
 307 static int
 308 spu_bfd_iovec_stat (bfd *abfd, void *stream, struct stat *sb)
 309 {
 310   /* We don't have an easy way of finding the size of embedded spu
 311      images.  We could parse the in-memory ELF header and section
 312      table to find the extent of the last section but that seems
 313      pointless when the size is needed only for checks of other
 314      parsed values in dbxread.c.  */
 315   memset (sb, 0, sizeof (struct stat));
 316   sb->st_size = INT_MAX;
 317   return 0;
 318 }
 319
 320 static gdb_bfd_ref_ptr
 321 spu_bfd_fopen (const char *name, CORE_ADDR addr)
 322 {
 323   CORE_ADDR *open_closure = XNEW (CORE_ADDR);
 324
 325   *open_closure = addr;
 326
 327   gdb_bfd_ref_ptr nbfd (gdb_bfd_openr_iovec (name, "elf32-spu",
 328                                              spu_bfd_iovec_open, open_closure,
 329                                              spu_bfd_iovec_pread,
 330                                              spu_bfd_iovec_close,
 331                                              spu_bfd_iovec_stat));
 332   if (nbfd == NULL)
 333     return NULL;
 334
 335   if (!bfd_check_format (nbfd.get (), bfd_object))
 336     return NULL;
 337
 338   return nbfd;
 339 }
 340
 341 /* Open shared library BFD.  */
 342 static gdb_bfd_ref_ptr
 343 spu_bfd_open (const char *pathname)
 344 {
 345   const char *original_name = strrchr (pathname, '@');
 346   asection *spu_name;
 347   unsigned long long addr;
 348   int fd;
 349
 350   /* Handle regular SVR4 libraries.  */
 351   if (!original_name)
 352     return svr4_so_ops.bfd_open (pathname);
 353
 354   /* Decode object ID.  */
 355   if (sscanf (original_name, "@0x%llx <%d>", &addr, &fd) != 2)
 356     internal_error (__FILE__, __LINE__, "bad object ID");
 357
 358   /* Open BFD representing SPE executable.  */
 359   gdb_bfd_ref_ptr abfd (spu_bfd_fopen (original_name, (CORE_ADDR) addr));
 360   if (abfd == NULL)
 361     error (_("Cannot read SPE executable at %s"), original_name);
 362
 363   /* Retrieve SPU name note.  */
 364   spu_name = bfd_get_section_by_name (abfd.get (), ".note.spu_name");
 365   if (spu_name)
 366     {
 367       int sect_size = bfd_section_size (abfd.get (), spu_name);
 368
 369       if (sect_size > 20)
 370         {
 371           char *buf
 372             = (char *) alloca (sect_size - 20 + strlen (original_name) + 1);
 373
 374           bfd_get_section_contents (abfd.get (), spu_name, buf, 20,
 375                                     sect_size - 20);
 376           buf[sect_size - 20] = '\0';
 377
 378           strcat (buf, original_name);
 379
 380           xfree ((char *)abfd->filename);
 381           abfd->filename = xstrdup (buf);
 382         }
 383     }
 384
 385   return abfd;
 386 }
 387
 388 /* Lookup global symbol in a SPE executable.  */
 389 static struct block_symbol
 390 spu_lookup_lib_symbol (struct objfile *objfile,
 391                        const char *name,
 392                        const domain_enum domain)
 393 {
 394   if (bfd_get_arch (objfile->obfd) == bfd_arch_spu)
 395     return lookup_global_symbol_from_objfile (objfile, name, domain);
 396
 397   if (svr4_so_ops.lookup_lib_global_symbol != NULL)
 398     return svr4_so_ops.lookup_lib_global_symbol (objfile, name, domain);
 399   return {};
 400 }
 401
 402 /* Enable shared library breakpoint.  */
 403 static int
 404 spu_enable_break (struct objfile *objfile)
 405 {
 406   struct bound_minimal_symbol spe_event_sym;
 407
 408   /* The libspe library will call __spe_context_update_event whenever any
 409      SPE context is allocated or destroyed.  */
 410   spe_event_sym = lookup_minimal_symbol ("__spe_context_update_event",
 411                                          NULL, objfile);
 412
 413   /* Place a solib_event breakpoint on the symbol.  */
 414   if (spe_event_sym.minsym)
 415     {
 416       CORE_ADDR addr = BMSYMBOL_VALUE_ADDRESS (spe_event_sym);
 417
 418       addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (), addr,
 419                                                  current_top_target ());
 420       create_solib_event_breakpoint (target_gdbarch (), addr);
 421       return 1;
 422     }
 423
 424   return 0;
 425 }
 426
 427 /* Enable shared library breakpoint for the
 428    OpenCL runtime running on the SPU.  */
 429 static void
 430 ocl_enable_break (struct objfile *objfile)
 431 {
 432   struct bound_minimal_symbol event_sym;
 433   struct bound_minimal_symbol addr_sym;
 434
 435   /* The OpenCL runtime on the SPU will call __opencl_program_update_event
 436      whenever an OpenCL program is loaded.  */
 437   event_sym = lookup_minimal_symbol ("__opencl_program_update_event", NULL,
 438                                      objfile);
 439   /* The PPU address of the OpenCL program can be found
 440      at opencl_elf_image_address.  */
 441   addr_sym = lookup_minimal_symbol ("opencl_elf_image_address", NULL, objfile);
 442
 443   if (event_sym.minsym && addr_sym.minsym)
 444     {
 445       /* Place a solib_event breakpoint on the symbol.  */
 446       CORE_ADDR event_addr = BMSYMBOL_VALUE_ADDRESS (event_sym);
 447       create_solib_event_breakpoint (get_objfile_arch (objfile), event_addr);
 448
 449       /* Store the address of the symbol that will point to OpenCL program
 450          using the per-objfile private data mechanism.  */
 451       if (objfile_data (objfile, ocl_program_data_key) == NULL)
 452         {
 453           CORE_ADDR *ocl_program_addr_base = OBSTACK_CALLOC (
 454                   &objfile->objfile_obstack,
 455                   objfile->sections_end - objfile->sections,
 456                   CORE_ADDR);
 457           *ocl_program_addr_base = BMSYMBOL_VALUE_ADDRESS (addr_sym);
 458           set_objfile_data (objfile, ocl_program_data_key,
 459                             ocl_program_addr_base);
 460         }
 461     }
 462 }
 463
 464 /* Create inferior hook.  */
 465 static void
 466 spu_solib_create_inferior_hook (int from_tty)
 467 {
 468   /* Handle SPE stand-alone executables.  */
 469   if (spu_standalone_p ())
 470     {
 471       /* After an SPE stand-alone executable was loaded, we'll receive
 472          an additional trap due to the binfmt_misc handler.  Make sure
 473          to skip that trap.  */
 474       spu_skip_standalone_loader ();
 475
 476       /* If the user established breakpoints before starting the inferior, GDB
 477          would attempt to insert those now.  This would fail because the SPU
 478          context has not yet been created and the SPU executable has not yet
 479          been loaded.  To prevent such failures, we disable all user-created
 480          breakpoints now; they will be re-enabled in spu_current_sos once the
 481          main SPU context has been detected.  */
 482       disable_breakpoints_before_startup ();
 483
 484       /* A special case arises when re-starting an executable, because at
 485          this point it still resides at the relocated address range that was
 486          determined during its last execution.  We need to undo the relocation
 487          so that that multi-architecture target recognizes the stand-alone
 488          initialization special case.  */
 489       spu_relocate_main_executable (-1);
 490     }
 491
 492   /* Call SVR4 hook -- this will re-insert the SVR4 solib breakpoints.  */
 493   svr4_so_ops.solib_create_inferior_hook (from_tty);
 494
 495   /* If the inferior is statically linked against libspe, we need to install
 496      our own solib breakpoint right now.  Otherwise, it will be installed by
 497      the solib_loaded observer below as soon as libspe is loaded.  */
 498   spu_enable_break (NULL);
 499 }
 500
 501 /* Install SPE "shared library" handling.  This is called by -tdep code
 502    that wants to support SPU as a secondary architecture.  */
 503 void
 504 set_spu_solib_ops (struct gdbarch *gdbarch)
 505 {
 506   static struct target_so_ops spu_so_ops;
 507
 508   /* Initialize this lazily, to avoid an initialization order
 509      dependency on solib-svr4.c's _initialize routine.  */
 510   if (spu_so_ops.current_sos == NULL)
 511     {
 512       spu_so_ops = svr4_so_ops;
 513       spu_so_ops.solib_create_inferior_hook = spu_solib_create_inferior_hook;
 514       spu_so_ops.relocate_section_addresses = spu_relocate_section_addresses;
 515       spu_so_ops.free_so = spu_free_so;
 516       spu_so_ops.current_sos = spu_current_sos;
 517       spu_so_ops.bfd_open = spu_bfd_open;
 518       spu_so_ops.lookup_lib_global_symbol = spu_lookup_lib_symbol;
 519     }
 520
 521   set_solib_ops (gdbarch, &spu_so_ops);
 522 }
 523
 524 /* Observer for the solib_loaded event.  Used to install our breakpoint
 525    if libspe is a shared library.  */
 526 static void
 527 spu_solib_loaded (struct so_list *so)
 528 {
 529   if (strstr (so->so_original_name, "/libspe") != NULL)
 530     {
 531       solib_read_symbols (so, 0);
 532       spu_enable_break (so->objfile);
 533     }
 534   /* In case the OpenCL runtime is loaded we install a breakpoint
 535      to get notified whenever an OpenCL program gets loaded.  */
 536   if (strstr (so->so_name, "CLRuntimeAccelCellSPU@") != NULL)
 537     {
 538       solib_read_symbols (so, 0);
 539       ocl_enable_break (so->objfile);
 540     }
 541 }
 542
 543 void
 544 _initialize_spu_solib (void)
 545 {
 546   gdb::observers::solib_loaded.attach (spu_solib_loaded);
 547   ocl_program_data_key = register_objfile_data ();
 548 }
 549