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