gdb/solib-spu.c

   1 /* Cell SPU GNU/Linux support -- shared library handling.
   2    Copyright (C) 2009-2018 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   struct objfile *objfile;
 105
 106   ALL_OBJFILES (objfile)
 107     {
 108       ocl_program_addr_base
 109         = (CORE_ADDR *) objfile_data (objfile, ocl_program_data_key);
 110       if (ocl_program_addr_base != NULL)
 111         {
 112           enum bfd_endian byte_order = bfd_big_endian (objfile->obfd)?
 113                                          BFD_ENDIAN_BIG : BFD_ENDIAN_LITTLE;
 114           TRY
 115             {
 116               CORE_ADDR data =
 117                 read_memory_unsigned_integer (*ocl_program_addr_base,
 118                                               sizeof (CORE_ADDR),
 119                                               byte_order);
 120               if (data != 0x0)
 121                 {
 122                   struct so_list *newobj;
 123
 124                   /* Allocate so_list structure.  */
 125                   newobj = XCNEW (struct so_list);
 126
 127                   /* Encode FD and object ID in path name.  */
 128                   xsnprintf (newobj->so_name, sizeof newobj->so_name, "@%s <%d>",
 129                              hex_string (data),
 130                              SPUADDR_SPU (*ocl_program_addr_base));
 131                   strcpy (newobj->so_original_name, newobj->so_name);
 132
 133                   *link_ptr = newobj;
 134                   link_ptr = &newobj->next;
 135                 }
 136             }
 137           CATCH (ex, RETURN_MASK_ALL)
 138             {
 139               /* Ignore memory errors.  */
 140               switch (ex.error)
 141                 {
 142                 case MEMORY_ERROR:
 143                   break;
 144                 default:
 145                   throw_exception (ex);
 146                   break;
 147                 }
 148             }
 149           END_CATCH
 150         }
 151     }
 152 }
 153
 154 /* Build a list of `struct so_list' objects describing the shared
 155    objects currently loaded in the inferior.  */
 156 static struct so_list *
 157 spu_current_sos (void)
 158 {
 159   enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
 160   struct so_list *head;
 161   struct so_list **link_ptr;
 162
 163   gdb_byte buf[MAX_SPE_FD * 4];
 164   int i, size;
 165
 166   /* First, retrieve the SVR4 shared library list.  */
 167   head = svr4_so_ops.current_sos ();
 168
 169   /* Append our libraries to the end of the list.  */
 170   for (link_ptr = &head; *link_ptr; link_ptr = &(*link_ptr)->next)
 171     ;
 172
 173   /* Determine list of SPU ids.  */
 174   size = target_read (&current_target, TARGET_OBJECT_SPU, NULL,
 175                       buf, 0, sizeof buf);
 176
 177   /* Do not add stand-alone SPE executable context as shared library,
 178      but relocate main SPE executable objfile.  */
 179   if (spu_standalone_p ())
 180     {
 181       if (size == 4)
 182         {
 183           int fd = extract_unsigned_integer (buf, 4, byte_order);
 184
 185           spu_relocate_main_executable (fd);
 186
 187           /* Re-enable breakpoints after main SPU context was established;
 188              see also comments in spu_solib_create_inferior_hook.  */
 189           enable_breakpoints_after_startup ();
 190         }
 191
 192       return head;
 193     }
 194
 195   /* Create an so_list entry for each SPU id.  */
 196   for (i = 0; i < size; i += 4)
 197     {
 198       int fd = extract_unsigned_integer (buf + i, 4, byte_order);
 199       struct so_list *newobj;
 200
 201       unsigned long long addr;
 202       char annex[32], id[100];
 203       int len;
 204
 205       /* Read object ID.  There's a race window where the inferior may have
 206          already created the SPE context, but not installed the object-id
 207          yet.  Skip such entries; we'll be back for them later.  */
 208       xsnprintf (annex, sizeof annex, "%d/object-id", fd);
 209       len = target_read (&current_target, TARGET_OBJECT_SPU, annex,
 210                          (gdb_byte *) id, 0, sizeof id);
 211       if (len <= 0 || len >= sizeof id)
 212         continue;
 213       id[len] = 0;
 214       if (sscanf (id, "0x%llx", &addr) != 1 || !addr)
 215         continue;
 216
 217       /* Allocate so_list structure.  */
 218       newobj = XCNEW (struct so_list);
 219
 220       /* Encode FD and object ID in path name.  Choose the name so as not
 221          to conflict with any (normal) SVR4 library path name.  */
 222       xsnprintf (newobj->so_name, sizeof newobj->so_name, "@%s <%d>",
 223                  hex_string (addr), fd);
 224       strcpy (newobj->so_original_name, newobj->so_name);
 225
 226       *link_ptr = newobj;
 227       link_ptr = &newobj->next;
 228     }
 229
 230   /* Append OpenCL sos.  */
 231   append_ocl_sos (link_ptr);
 232
 233   return head;
 234 }
 235
 236 /* Free so_list information.  */
 237 static void
 238 spu_free_so (struct so_list *so)
 239 {
 240   if (so->so_original_name[0] != '@')
 241     svr4_so_ops.free_so (so);
 242 }
 243
 244 /* Relocate section addresses.  */
 245 static void
 246 spu_relocate_section_addresses (struct so_list *so,
 247                                 struct target_section *sec)
 248 {
 249   if (so->so_original_name[0] != '@')
 250     svr4_so_ops.relocate_section_addresses (so, sec);
 251   else
 252     {
 253       unsigned long long addr;
 254       int fd;
 255
 256       /* Set addr_low/high to just LS offset for display.  */
 257       if (so->addr_low == 0 && so->addr_high == 0
 258           && strcmp (sec->the_bfd_section->name, ".text") == 0)
 259         {
 260           so->addr_low = sec->addr;
 261           so->addr_high = sec->endaddr;
 262         }
 263
 264       /* Decode object ID.  */
 265       if (sscanf (so->so_original_name, "@0x%llx <%d>", &addr, &fd) != 2)
 266         internal_error (__FILE__, __LINE__, "bad object ID");
 267
 268       sec->addr = SPUADDR (fd, sec->addr);
 269       sec->endaddr = SPUADDR (fd, sec->endaddr);
 270     }
 271 }
 272
 273
 274 /* Inferior memory should contain an SPE executable image at location ADDR.
 275    Allocate a BFD representing that executable.  Return NULL on error.  */
 276
 277 static void *
 278 spu_bfd_iovec_open (bfd *nbfd, void *open_closure)
 279 {
 280   return open_closure;
 281 }
 282
 283 static int
 284 spu_bfd_iovec_close (bfd *nbfd, void *stream)
 285 {
 286   xfree (stream);
 287
 288   /* Zero means success.  */
 289   return 0;
 290 }
 291
 292 static file_ptr
 293 spu_bfd_iovec_pread (bfd *abfd, void *stream, void *buf,
 294                      file_ptr nbytes, file_ptr offset)
 295 {
 296   CORE_ADDR addr = *(CORE_ADDR *)stream;
 297   int ret;
 298
 299   ret = target_read_memory (addr + offset, (gdb_byte *) buf, nbytes);
 300   if (ret != 0)
 301     {
 302       bfd_set_error (bfd_error_invalid_operation);
 303       return -1;
 304     }
 305
 306   return nbytes;
 307 }
 308
 309 static int
 310 spu_bfd_iovec_stat (bfd *abfd, void *stream, struct stat *sb)
 311 {
 312   /* We don't have an easy way of finding the size of embedded spu
 313      images.  We could parse the in-memory ELF header and section
 314      table to find the extent of the last section but that seems
 315      pointless when the size is needed only for checks of other
 316      parsed values in dbxread.c.  */
 317   memset (sb, 0, sizeof (struct stat));
 318   sb->st_size = INT_MAX;
 319   return 0;
 320 }
 321
 322 static gdb_bfd_ref_ptr
 323 spu_bfd_fopen (const char *name, CORE_ADDR addr)
 324 {
 325   CORE_ADDR *open_closure = XNEW (CORE_ADDR);
 326
 327   *open_closure = addr;
 328
 329   gdb_bfd_ref_ptr nbfd (gdb_bfd_openr_iovec (name, "elf32-spu",
 330                                              spu_bfd_iovec_open, open_closure,
 331                                              spu_bfd_iovec_pread,
 332                                              spu_bfd_iovec_close,
 333                                              spu_bfd_iovec_stat));
 334   if (nbfd == NULL)
 335     return NULL;
 336
 337   if (!bfd_check_format (nbfd.get (), bfd_object))
 338     return NULL;
 339
 340   return nbfd;
 341 }
 342
 343 /* Open shared library BFD.  */
 344 static gdb_bfd_ref_ptr
 345 spu_bfd_open (const char *pathname)
 346 {
 347   const char *original_name = strrchr (pathname, '@');
 348   asection *spu_name;
 349   unsigned long long addr;
 350   int fd;
 351
 352   /* Handle regular SVR4 libraries.  */
 353   if (!original_name)
 354     return svr4_so_ops.bfd_open (pathname);
 355
 356   /* Decode object ID.  */
 357   if (sscanf (original_name, "@0x%llx <%d>", &addr, &fd) != 2)
 358     internal_error (__FILE__, __LINE__, "bad object ID");
 359
 360   /* Open BFD representing SPE executable.  */
 361   gdb_bfd_ref_ptr abfd (spu_bfd_fopen (original_name, (CORE_ADDR) addr));
 362   if (abfd == NULL)
 363     error (_("Cannot read SPE executable at %s"), original_name);
 364
 365   /* Retrieve SPU name note.  */
 366   spu_name = bfd_get_section_by_name (abfd.get (), ".note.spu_name");
 367   if (spu_name)
 368     {
 369       int sect_size = bfd_section_size (abfd.get (), spu_name);
 370
 371       if (sect_size > 20)
 372         {
 373           char *buf
 374             = (char *) alloca (sect_size - 20 + strlen (original_name) + 1);
 375
 376           bfd_get_section_contents (abfd.get (), spu_name, buf, 20,
 377                                     sect_size - 20);
 378           buf[sect_size - 20] = '\0';
 379
 380           strcat (buf, original_name);
 381
 382           xfree ((char *)abfd->filename);
 383           abfd->filename = xstrdup (buf);
 384         }
 385     }
 386
 387   return abfd;
 388 }
 389
 390 /* Lookup global symbol in a SPE executable.  */
 391 static struct block_symbol
 392 spu_lookup_lib_symbol (struct objfile *objfile,
 393                        const char *name,
 394                        const domain_enum domain)
 395 {
 396   if (bfd_get_arch (objfile->obfd) == bfd_arch_spu)
 397     return lookup_global_symbol_from_objfile (objfile, name, domain);
 398
 399   if (svr4_so_ops.lookup_lib_global_symbol != NULL)
 400     return svr4_so_ops.lookup_lib_global_symbol (objfile, name, domain);
 401   return (struct block_symbol) {NULL, NULL};
 402 }
 403
 404 /* Enable shared library breakpoint.  */
 405 static int
 406 spu_enable_break (struct objfile *objfile)
 407 {
 408   struct bound_minimal_symbol spe_event_sym;
 409
 410   /* The libspe library will call __spe_context_update_event whenever any
 411      SPE context is allocated or destroyed.  */
 412   spe_event_sym = lookup_minimal_symbol ("__spe_context_update_event",
 413                                          NULL, objfile);
 414
 415   /* Place a solib_event breakpoint on the symbol.  */
 416   if (spe_event_sym.minsym)
 417     {
 418       CORE_ADDR addr = BMSYMBOL_VALUE_ADDRESS (spe_event_sym);
 419
 420       addr = gdbarch_convert_from_func_ptr_addr (target_gdbarch (), addr,
 421                                                  &current_target);
 422       create_solib_event_breakpoint (target_gdbarch (), addr);
 423       return 1;
 424     }
 425
 426   return 0;
 427 }
 428
 429 /* Enable shared library breakpoint for the
 430    OpenCL runtime running on the SPU.  */
 431 static void
 432 ocl_enable_break (struct objfile *objfile)
 433 {
 434   struct bound_minimal_symbol event_sym;
 435   struct bound_minimal_symbol addr_sym;
 436
 437   /* The OpenCL runtime on the SPU will call __opencl_program_update_event
 438      whenever an OpenCL program is loaded.  */
 439   event_sym = lookup_minimal_symbol ("__opencl_program_update_event", NULL,
 440                                      objfile);
 441   /* The PPU address of the OpenCL program can be found
 442      at opencl_elf_image_address.  */
 443   addr_sym = lookup_minimal_symbol ("opencl_elf_image_address", NULL, objfile);
 444
 445   if (event_sym.minsym && addr_sym.minsym)
 446     {
 447       /* Place a solib_event breakpoint on the symbol.  */
 448       CORE_ADDR event_addr = BMSYMBOL_VALUE_ADDRESS (event_sym);
 449       create_solib_event_breakpoint (get_objfile_arch (objfile), event_addr);
 450
 451       /* Store the address of the symbol that will point to OpenCL program
 452          using the per-objfile private data mechanism.  */
 453       if (objfile_data (objfile, ocl_program_data_key) == NULL)
 454         {
 455           CORE_ADDR *ocl_program_addr_base = OBSTACK_CALLOC (
 456                   &objfile->objfile_obstack,
 457                   objfile->sections_end - objfile->sections,
 458                   CORE_ADDR);
 459           *ocl_program_addr_base = BMSYMBOL_VALUE_ADDRESS (addr_sym);
 460           set_objfile_data (objfile, ocl_program_data_key,
 461                             ocl_program_addr_base);
 462         }
 463     }
 464 }
 465
 466 /* Create inferior hook.  */
 467 static void
 468 spu_solib_create_inferior_hook (int from_tty)
 469 {
 470   /* Handle SPE stand-alone executables.  */
 471   if (spu_standalone_p ())
 472     {
 473       /* After an SPE stand-alone executable was loaded, we'll receive
 474          an additional trap due to the binfmt_misc handler.  Make sure
 475          to skip that trap.  */
 476       spu_skip_standalone_loader ();
 477
 478       /* If the user established breakpoints before starting the inferior, GDB
 479          would attempt to insert those now.  This would fail because the SPU
 480          context has not yet been created and the SPU executable has not yet
 481          been loaded.  To prevent such failures, we disable all user-created
 482          breakpoints now; they will be re-enabled in spu_current_sos once the
 483          main SPU context has been detected.  */
 484       disable_breakpoints_before_startup ();
 485
 486       /* A special case arises when re-starting an executable, because at
 487          this point it still resides at the relocated address range that was
 488          determined during its last execution.  We need to undo the relocation
 489          so that that multi-architecture target recognizes the stand-alone
 490          initialization special case.  */
 491       spu_relocate_main_executable (-1);
 492     }
 493
 494   /* Call SVR4 hook -- this will re-insert the SVR4 solib breakpoints.  */
 495   svr4_so_ops.solib_create_inferior_hook (from_tty);
 496
 497   /* If the inferior is statically linked against libspe, we need to install
 498      our own solib breakpoint right now.  Otherwise, it will be installed by
 499      the solib_loaded observer below as soon as libspe is loaded.  */
 500   spu_enable_break (NULL);
 501 }
 502
 503 /* Install SPE "shared library" handling.  This is called by -tdep code
 504    that wants to support SPU as a secondary architecture.  */
 505 void
 506 set_spu_solib_ops (struct gdbarch *gdbarch)
 507 {
 508   static struct target_so_ops spu_so_ops;
 509
 510   /* Initialize this lazily, to avoid an initialization order
 511      dependency on solib-svr4.c's _initialize routine.  */
 512   if (spu_so_ops.current_sos == NULL)
 513     {
 514       spu_so_ops = svr4_so_ops;
 515       spu_so_ops.solib_create_inferior_hook = spu_solib_create_inferior_hook;
 516       spu_so_ops.relocate_section_addresses = spu_relocate_section_addresses;
 517       spu_so_ops.free_so = spu_free_so;
 518       spu_so_ops.current_sos = spu_current_sos;
 519       spu_so_ops.bfd_open = spu_bfd_open;
 520       spu_so_ops.lookup_lib_global_symbol = spu_lookup_lib_symbol;
 521     }
 522
 523   set_solib_ops (gdbarch, &spu_so_ops);
 524 }
 525
 526 /* Observer for the solib_loaded event.  Used to install our breakpoint
 527    if libspe is a shared library.  */
 528 static void
 529 spu_solib_loaded (struct so_list *so)
 530 {
 531   if (strstr (so->so_original_name, "/libspe") != NULL)
 532     {
 533       solib_read_symbols (so, 0);
 534       spu_enable_break (so->objfile);
 535     }
 536   /* In case the OpenCL runtime is loaded we install a breakpoint
 537      to get notified whenever an OpenCL program gets loaded.  */
 538   if (strstr (so->so_name, "CLRuntimeAccelCellSPU@") != NULL)
 539     {
 540       solib_read_symbols (so, 0);
 541       ocl_enable_break (so->objfile);
 542     }
 543 }
 544
 545 void
 546 _initialize_spu_solib (void)
 547 {
 548   gdb::observers::solib_loaded.attach (spu_solib_loaded);
 549   ocl_program_data_key = register_objfile_data ();
 550 }
 551