1 /* BFD back-end for linux flavored m68k a.out binaries.
2 Copyright 1992, 1993, 1994, 1995, 1996, 1997, 1999, 2000, 2001, 2002,
3 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
5 This file is part of BFD, the Binary File Descriptor library.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, USA. */
22 #define TARGET_PAGE_SIZE 4096
23 #define ZMAGIC_DISK_BLOCK_SIZE 1024
24 #define SEGMENT_SIZE TARGET_PAGE_SIZE
25 #define TEXT_START_ADDR 0x0
27 #define MACHTYPE_OK(mtype) ((mtype) == M_68020 || (mtype) == M_UNKNOWN)
32 #include "aout/aout64.h"
33 #include "aout/stab_gnu.h"
35 #include "libaout.h" /* BFD a.out internal data structures */
37 #define TARGET_IS_BIG_ENDIAN_P
38 #define DEFAULT_ARCH bfd_arch_m68k
40 /* Do not "beautify" the CONCAT* macro args. Traditional C will not
41 remove whitespace added here, and thus will fail to concatenate
43 #define MY(OP) CONCAT2 (m68klinux_,OP)
44 #define TARGETNAME "a.out-m68k-linux"
46 extern const bfd_target MY(vec);
48 /* We always generate QMAGIC files in preference to ZMAGIC files. It
49 would be possible to make this a linker option, if that ever
52 static void MY_final_link_callback
53 PARAMS ((bfd *, file_ptr *, file_ptr *, file_ptr *));
54 static bfd_boolean m68klinux_bfd_final_link
55 PARAMS ((bfd *, struct bfd_link_info *));
56 static bfd_boolean m68klinux_write_object_contents PARAMS ((bfd *));
59 m68klinux_bfd_final_link (abfd, info)
61 struct bfd_link_info *info;
63 obj_aout_subformat (abfd) = q_magic_format;
64 return NAME(aout,final_link) (abfd, info, MY_final_link_callback);
67 #define MY_bfd_final_link m68klinux_bfd_final_link
69 /* Set the machine type correctly. */
72 m68klinux_write_object_contents (abfd)
75 struct external_exec exec_bytes;
76 struct internal_exec *execp = exec_hdr (abfd);
78 N_SET_MACHTYPE (*execp, M_68020);
80 obj_reloc_entry_size (abfd) = RELOC_STD_SIZE;
82 WRITE_HEADERS(abfd, execp);
87 #define MY_write_object_contents m68klinux_write_object_contents
89 /* Code to link against Linux a.out shared libraries. */
91 /* See if a symbol name is a reference to the global offset table. */
93 #ifndef GOT_REF_PREFIX
94 #define GOT_REF_PREFIX "__GOT_"
97 #define IS_GOT_SYM(name) (CONST_STRNEQ (name, GOT_REF_PREFIX))
99 /* See if a symbol name is a reference to the procedure linkage table. */
101 #ifndef PLT_REF_PREFIX
102 #define PLT_REF_PREFIX "__PLT_"
105 #define IS_PLT_SYM(name) (CONST_STRNEQ (name, PLT_REF_PREFIX))
107 /* This string is used to generate specialized error messages. */
110 #define NEEDS_SHRLIB "__NEEDS_SHRLIB_"
113 /* This special symbol is a set vector that contains a list of
114 pointers to fixup tables. It will be present in any dynamically
115 linked file. The linker generated fixup table should also be added
116 to the list, and it should always appear in the second slot (the
117 first one is a dummy with a magic number that is defined in
120 #ifndef SHARABLE_CONFLICTS
121 #define SHARABLE_CONFLICTS "__SHARABLE_CONFLICTS__"
124 /* We keep a list of fixups. The terminology is a bit strange, but
125 each fixup contains two 32 bit numbers. A regular fixup contains
126 an address and a pointer, and at runtime we should store the
127 address at the location pointed to by the pointer. A builtin fixup
128 contains two pointers, and we should read the address using one
129 pointer and store it at the location pointed to by the other
130 pointer. Builtin fixups come into play when we have duplicate
131 __GOT__ symbols for the same variable. The builtin fixup will copy
132 the GOT pointer from one over into the other. */
137 struct linux_link_hash_entry *h;
140 /* Nonzero if this is a jump instruction that needs to be fixed,
141 zero if this is just a pointer */
147 /* We don't need a special hash table entry structure, but we do need
148 to keep some information between linker passes, so we use a special
151 struct linux_link_hash_entry
153 struct aout_link_hash_entry root;
156 struct linux_link_hash_table
158 struct aout_link_hash_table root;
160 /* First dynamic object found in link. */
163 /* Number of fixups. */
166 /* Number of builtin fixups. */
167 size_t local_builtins;
169 /* List of fixups. */
170 struct fixup *fixup_list;
173 static struct bfd_hash_entry *linux_link_hash_newfunc
174 PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
175 static struct bfd_link_hash_table *linux_link_hash_table_create
177 static struct fixup *new_fixup
178 PARAMS ((struct bfd_link_info *, struct linux_link_hash_entry *,
180 static bfd_boolean linux_link_create_dynamic_sections
181 PARAMS ((bfd *, struct bfd_link_info *));
182 static bfd_boolean linux_add_one_symbol
183 PARAMS ((struct bfd_link_info *, bfd *, const char *, flagword, asection *,
184 bfd_vma, const char *, bfd_boolean, bfd_boolean,
185 struct bfd_link_hash_entry **));
186 static bfd_boolean linux_tally_symbols
187 PARAMS ((struct linux_link_hash_entry *, PTR));
188 static bfd_boolean linux_finish_dynamic_link
189 PARAMS ((bfd *, struct bfd_link_info *));
191 /* Routine to create an entry in an Linux link hash table. */
193 static struct bfd_hash_entry *
194 linux_link_hash_newfunc (entry, table, string)
195 struct bfd_hash_entry *entry;
196 struct bfd_hash_table *table;
199 struct linux_link_hash_entry *ret = (struct linux_link_hash_entry *) entry;
201 /* Allocate the structure if it has not already been allocated by a
203 if (ret == (struct linux_link_hash_entry *) NULL)
204 ret = ((struct linux_link_hash_entry *)
205 bfd_hash_allocate (table, sizeof (struct linux_link_hash_entry)));
207 return (struct bfd_hash_entry *) ret;
209 /* Call the allocation method of the superclass. */
210 ret = ((struct linux_link_hash_entry *)
211 NAME(aout,link_hash_newfunc) ((struct bfd_hash_entry *) ret,
215 /* Set local fields; there aren't any. */
218 return (struct bfd_hash_entry *) ret;
221 /* Create a Linux link hash table. */
223 static struct bfd_link_hash_table *
224 linux_link_hash_table_create (abfd)
227 struct linux_link_hash_table *ret;
228 bfd_size_type amt = sizeof (struct linux_link_hash_table);
230 ret = (struct linux_link_hash_table *) bfd_malloc (amt);
231 if (ret == (struct linux_link_hash_table *) NULL)
233 bfd_set_error (bfd_error_no_memory);
234 return (struct bfd_link_hash_table *) NULL;
236 if (!NAME(aout,link_hash_table_init) (&ret->root, abfd,
237 linux_link_hash_newfunc,
238 sizeof (struct linux_link_hash_entry)))
241 return (struct bfd_link_hash_table *) NULL;
245 ret->fixup_count = 0;
246 ret->local_builtins = 0;
247 ret->fixup_list = NULL;
249 return &ret->root.root;
252 /* Look up an entry in a Linux link hash table. */
254 #define linux_link_hash_lookup(table, string, create, copy, follow) \
255 ((struct linux_link_hash_entry *) \
256 aout_link_hash_lookup (&(table)->root, (string), (create), (copy),\
259 /* Traverse a Linux link hash table. */
261 #define linux_link_hash_traverse(table, func, info) \
262 (aout_link_hash_traverse \
264 (bfd_boolean (*) PARAMS ((struct aout_link_hash_entry *, PTR))) (func), \
267 /* Get the Linux link hash table from the info structure. This is
270 #define linux_hash_table(p) ((struct linux_link_hash_table *) ((p)->hash))
272 /* Store the information for a new fixup. */
274 static struct fixup *
275 new_fixup (info, h, value, builtin)
276 struct bfd_link_info *info;
277 struct linux_link_hash_entry *h;
283 f = (struct fixup *) bfd_hash_allocate (&info->hash->table,
284 sizeof (struct fixup));
287 f->next = linux_hash_table (info)->fixup_list;
288 linux_hash_table (info)->fixup_list = f;
291 f->builtin = builtin;
293 ++linux_hash_table (info)->fixup_count;
297 /* We come here once we realize that we are going to link to a shared
298 library. We need to create a special section that contains the
299 fixup table, and we ultimately need to add a pointer to this into
300 the set vector for SHARABLE_CONFLICTS. At this point we do not
301 know the size of the section, but that's OK - we just need to
302 create it for now. */
305 linux_link_create_dynamic_sections (abfd, info)
307 struct bfd_link_info *info ATTRIBUTE_UNUSED;
310 register asection *s;
312 /* Note that we set the SEC_IN_MEMORY flag. */
313 flags = SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY;
315 /* We choose to use the name ".linux-dynamic" for the fixup table.
317 s = bfd_make_section_with_flags (abfd, ".linux-dynamic", flags);
319 || ! bfd_set_section_alignment (abfd, s, 2))
327 /* Function to add a single symbol to the linker hash table. This is
328 a wrapper around _bfd_generic_link_add_one_symbol which handles the
329 tweaking needed for dynamic linking support. */
332 linux_add_one_symbol (info, abfd, name, flags, section, value, string,
333 copy, collect, hashp)
334 struct bfd_link_info *info;
343 struct bfd_link_hash_entry **hashp;
345 struct linux_link_hash_entry *h;
348 /* Look up and see if we already have this symbol in the hash table.
349 If we do, and the defining entry is from a shared library, we
350 need to create the dynamic sections.
352 FIXME: What if abfd->xvec != info->output_bfd->xvec? We may
353 want to be able to link Linux a.out and ELF objects together,
354 but serious confusion is possible. */
358 if (! info->relocatable
359 && linux_hash_table (info)->dynobj == NULL
360 && strcmp (name, SHARABLE_CONFLICTS) == 0
361 && (flags & BSF_CONSTRUCTOR) != 0
362 && abfd->xvec == info->output_bfd->xvec)
364 if (! linux_link_create_dynamic_sections (abfd, info))
366 linux_hash_table (info)->dynobj = abfd;
370 if (bfd_is_abs_section (section)
371 && abfd->xvec == info->output_bfd->xvec)
373 h = linux_link_hash_lookup (linux_hash_table (info), name, FALSE,
376 && (h->root.root.type == bfd_link_hash_defined
377 || h->root.root.type == bfd_link_hash_defweak))
382 *hashp = (struct bfd_link_hash_entry *) h;
384 f = new_fixup (info, h, value, ! IS_PLT_SYM (name));
387 f->jump = IS_PLT_SYM (name);
393 /* Do the usual procedure for adding a symbol. */
394 if (! _bfd_generic_link_add_one_symbol (info, abfd, name, flags, section,
395 value, string, copy, collect,
399 /* Insert a pointer to our table in the set vector. The dynamic
400 linker requires this information */
405 /* Here we do our special thing to add the pointer to the
406 dynamic section in the SHARABLE_CONFLICTS set vector. */
407 s = bfd_get_section_by_name (linux_hash_table (info)->dynobj,
409 BFD_ASSERT (s != NULL);
411 if (! (_bfd_generic_link_add_one_symbol
412 (info, linux_hash_table (info)->dynobj, SHARABLE_CONFLICTS,
413 BSF_GLOBAL | BSF_CONSTRUCTOR, s, (bfd_vma) 0, NULL,
414 FALSE, FALSE, NULL)))
421 /* We will crawl the hash table and come here for every global symbol.
422 We will examine each entry and see if there are indications that we
423 need to add a fixup. There are two possible cases - one is where
424 you have duplicate definitions of PLT or GOT symbols - these will
425 have already been caught and added as "builtin" fixups. If we find
426 that the corresponding non PLT/GOT symbol is also present, we
427 convert it to a regular fixup instead.
429 This function is called via linux_link_hash_traverse. */
432 linux_tally_symbols (h, data)
433 struct linux_link_hash_entry *h;
436 struct bfd_link_info *info = (struct bfd_link_info *) data;
437 struct fixup *f, *f1;
439 struct linux_link_hash_entry *h1, *h2;
442 if (h->root.root.type == bfd_link_hash_warning)
443 h = (struct linux_link_hash_entry *) h->root.root.u.i.link;
445 if (h->root.root.type == bfd_link_hash_undefined
446 && CONST_STRNEQ (h->root.root.root.string, NEEDS_SHRLIB))
452 name = h->root.root.root.string + sizeof NEEDS_SHRLIB - 1;
453 p = strrchr (name, '_');
455 alloc = (char *) bfd_malloc ((bfd_size_type) strlen (name) + 1);
457 if (p == NULL || alloc == NULL)
458 (*_bfd_error_handler) (_("Output file requires shared library `%s'\n"),
462 strcpy (alloc, name);
463 p = strrchr (alloc, '_');
465 (*_bfd_error_handler)
466 (_("Output file requires shared library `%s.so.%s'\n"),
474 /* If this symbol is not a PLT/GOT, we do not even need to look at it */
475 is_plt = IS_PLT_SYM (h->root.root.root.string);
477 if (is_plt || IS_GOT_SYM (h->root.root.root.string))
479 /* Look up this symbol twice. Once just as a regular lookup,
480 and then again following all of the indirect links until we
481 reach a real symbol. */
482 h1 = linux_link_hash_lookup (linux_hash_table (info),
483 (h->root.root.root.string
484 + sizeof PLT_REF_PREFIX - 1),
486 /* h2 does not follow indirect symbols. */
487 h2 = linux_link_hash_lookup (linux_hash_table (info),
488 (h->root.root.root.string
489 + sizeof PLT_REF_PREFIX - 1),
490 FALSE, FALSE, FALSE);
492 /* The real symbol must exist but if it is also an ABS symbol,
493 there is no need to have a fixup. This is because they both
494 came from the same library. If on the other hand, we had to
495 use an indirect symbol to get to the real symbol, we add the
496 fixup anyway, since there are cases where these symbols come
497 from different shared libraries */
499 && (((h1->root.root.type == bfd_link_hash_defined
500 || h1->root.root.type == bfd_link_hash_defweak)
501 && ! bfd_is_abs_section (h1->root.root.u.def.section))
502 || h2->root.root.type == bfd_link_hash_indirect))
504 /* See if there is a "builtin" fixup already present
505 involving this symbol. If so, convert it to a regular
506 fixup. In the end, this relaxes some of the requirements
507 about the order of performing fixups. */
509 for (f1 = linux_hash_table (info)->fixup_list;
513 if ((f1->h != h && f1->h != h1)
514 || (! f1->builtin && ! f1->jump))
519 && bfd_is_abs_section (h->root.root.u.def.section))
521 f = new_fixup (info, h1, f1->h->root.root.u.def.value, 0);
530 && bfd_is_abs_section (h->root.root.u.def.section))
532 f = new_fixup (info, h1, h->root.root.u.def.value, 0);
535 /* FIXME: No way to return error. */
542 /* Quick and dirty way of stripping these symbols from the
544 if (bfd_is_abs_section (h->root.root.u.def.section))
545 h->root.written = TRUE;
551 /* This is called to set the size of the .linux-dynamic section is.
552 It is called by the Linux linker emulation before_allocation
553 routine. We have finished reading all of the input files, and now
554 we just scan the hash tables to find out how many additional fixups
558 bfd_m68klinux_size_dynamic_sections (output_bfd, info)
560 struct bfd_link_info *info;
565 if (output_bfd->xvec != &MY(vec))
568 /* First find the fixups... */
569 linux_link_hash_traverse (linux_hash_table (info),
573 /* If there are builtin fixups, leave room for a marker. This is
574 used by the dynamic linker so that it knows that all that follow
575 are builtin fixups instead of regular fixups. */
576 for (f = linux_hash_table (info)->fixup_list; f != NULL; f = f->next)
580 ++linux_hash_table (info)->fixup_count;
581 ++linux_hash_table (info)->local_builtins;
586 if (linux_hash_table (info)->dynobj == NULL)
588 if (linux_hash_table (info)->fixup_count > 0)
593 /* Allocate memory for our fixup table. We will fill it in later. */
594 s = bfd_get_section_by_name (linux_hash_table (info)->dynobj,
598 s->size = linux_hash_table (info)->fixup_count + 1;
600 s->contents = (bfd_byte *) bfd_zalloc (output_bfd, s->size);
601 if (s->contents == NULL)
603 bfd_set_error (bfd_error_no_memory);
611 /* We come here once we are ready to actually write the fixup table to
612 the output file. Scan the fixup tables and so forth and generate
613 the stuff we need. */
616 linux_finish_dynamic_link (output_bfd, info)
618 struct bfd_link_info *info;
620 asection *s, *os, *is;
621 bfd_byte *fixup_table;
622 struct linux_link_hash_entry *h;
624 unsigned int new_addr;
626 unsigned int fixups_written;
628 if (linux_hash_table (info)->dynobj == NULL)
631 s = bfd_get_section_by_name (linux_hash_table (info)->dynobj,
633 BFD_ASSERT (s != NULL);
634 os = s->output_section;
637 #ifdef LINUX_LINK_DEBUG
638 printf ("Fixup table file offset: %x VMA: %x\n",
639 os->filepos + s->output_offset,
640 os->vma + s->output_offset);
643 fixup_table = s->contents;
644 bfd_put_32 (output_bfd, (bfd_vma) linux_hash_table (info)->fixup_count,
648 /* Fill in fixup table. */
649 for (f = linux_hash_table (info)->fixup_list; f != NULL; f = f->next)
654 if (f->h->root.root.type != bfd_link_hash_defined
655 && f->h->root.root.type != bfd_link_hash_defweak)
657 (*_bfd_error_handler)
658 (_("Symbol %s not defined for fixups\n"),
659 f->h->root.root.root.string);
663 is = f->h->root.root.u.def.section;
664 section_offset = is->output_section->vma + is->output_offset;
665 new_addr = f->h->root.root.u.def.value + section_offset;
667 #ifdef LINUX_LINK_DEBUG
668 printf ("Fixup(%d) %s: %x %x\n",f->jump, f->h->root.root.string,
674 bfd_put_32 (output_bfd, (bfd_vma) new_addr, fixup_table);
676 bfd_put_32 (output_bfd, f->value + 2, fixup_table);
681 bfd_put_32 (output_bfd, (bfd_vma) new_addr, fixup_table);
683 bfd_put_32 (output_bfd, f->value, fixup_table);
689 if (linux_hash_table (info)->local_builtins != 0)
691 /* Special marker so we know to switch to the other type of fixup */
692 bfd_put_32 (output_bfd, (bfd_vma) 0, fixup_table);
694 bfd_put_32 (output_bfd, (bfd_vma) 0, fixup_table);
697 for (f = linux_hash_table (info)->fixup_list; f != NULL; f = f->next)
702 if (f->h->root.root.type != bfd_link_hash_defined
703 && f->h->root.root.type != bfd_link_hash_defweak)
705 (*_bfd_error_handler)
706 (_("Symbol %s not defined for fixups\n"),
707 f->h->root.root.root.string);
711 is = f->h->root.root.u.def.section;
712 section_offset = is->output_section->vma + is->output_offset;
713 new_addr = f->h->root.root.u.def.value + section_offset;
715 #ifdef LINUX_LINK_DEBUG
716 printf ("Fixup(B) %s: %x %x\n", f->h->root.root.string,
720 bfd_put_32 (output_bfd, (bfd_vma) new_addr, fixup_table);
722 bfd_put_32 (output_bfd, f->value, fixup_table);
728 if (linux_hash_table (info)->fixup_count != fixups_written)
730 (*_bfd_error_handler) (_("Warning: fixup count mismatch\n"));
731 while (linux_hash_table (info)->fixup_count > fixups_written)
733 bfd_put_32 (output_bfd, (bfd_vma) 0, fixup_table);
735 bfd_put_32 (output_bfd, (bfd_vma) 0, fixup_table);
741 h = linux_link_hash_lookup (linux_hash_table (info),
742 "__BUILTIN_FIXUPS__",
743 FALSE, FALSE, FALSE);
746 && (h->root.root.type == bfd_link_hash_defined
747 || h->root.root.type == bfd_link_hash_defweak))
749 is = h->root.root.u.def.section;
750 section_offset = is->output_section->vma + is->output_offset;
751 new_addr = h->root.root.u.def.value + section_offset;
753 #ifdef LINUX_LINK_DEBUG
754 printf ("Builtin fixup table at %x\n", new_addr);
757 bfd_put_32 (output_bfd, (bfd_vma) new_addr, fixup_table);
760 bfd_put_32 (output_bfd, (bfd_vma) 0, fixup_table);
762 if (bfd_seek (output_bfd, (file_ptr) (os->filepos + s->output_offset),
766 if (bfd_bwrite ((PTR) s->contents, s->size, output_bfd) != s->size)
772 #define MY_bfd_link_hash_table_create linux_link_hash_table_create
773 #define MY_add_one_symbol linux_add_one_symbol
774 #define MY_finish_dynamic_link linux_finish_dynamic_link
776 #define MY_zmagic_contiguous 1
778 #include "aout-target.h"