1 /* BFD back-end for linux flavored m68k a.out binaries.
2 Copyright (C) 1992, 93, 94, 95, 96, 1997 Free Software Foundation, Inc.
4 This file is part of BFD, the Binary File Descriptor library.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
20 #define TARGET_PAGE_SIZE 4096
21 #define ZMAGIC_DISK_BLOCK_SIZE 1024
22 #define SEGMENT_SIZE TARGET_PAGE_SIZE
23 #define TEXT_START_ADDR 0x0
24 #define N_SHARED_LIB(x) 0
25 #define BYTES_IN_WORD 4
30 #include "aout/aout64.h"
31 #include "aout/stab_gnu.h"
33 #include "libaout.h" /* BFD a.out internal data structures */
35 #define TARGET_IS_BIG_ENDIAN_P
36 #define DEFAULT_ARCH bfd_arch_m68k
37 #define MY(OP) CAT(m68klinux_,OP)
38 #define TARGETNAME "a.out-m68k-linux"
40 extern const bfd_target MY(vec);
42 /* We always generate QMAGIC files in preference to ZMAGIC files. It
43 would be possible to make this a linker option, if that ever
46 static void MY_final_link_callback
47 PARAMS ((bfd *, file_ptr *, file_ptr *, file_ptr *));
48 static boolean m68klinux_bfd_final_link
49 PARAMS ((bfd *, struct bfd_link_info *));
50 static boolean m68klinux_write_object_contents PARAMS ((bfd *));
53 m68klinux_bfd_final_link (abfd, info)
55 struct bfd_link_info *info;
57 obj_aout_subformat (abfd) = q_magic_format;
58 return NAME(aout,final_link) (abfd, info, MY_final_link_callback);
61 #define MY_bfd_final_link m68klinux_bfd_final_link
63 /* Set the machine type correctly. */
66 m68klinux_write_object_contents (abfd)
69 struct external_exec exec_bytes;
70 struct internal_exec *execp = exec_hdr (abfd);
72 N_SET_MACHTYPE (*execp, M_68020);
74 obj_reloc_entry_size (abfd) = RELOC_STD_SIZE;
76 WRITE_HEADERS(abfd, execp);
81 #define MY_write_object_contents m68klinux_write_object_contents
83 /* Code to link against Linux a.out shared libraries. */
85 /* See if a symbol name is a reference to the global offset table. */
87 #ifndef GOT_REF_PREFIX
88 #define GOT_REF_PREFIX "__GOT_"
91 #define IS_GOT_SYM(name) \
92 (strncmp (name, GOT_REF_PREFIX, sizeof GOT_REF_PREFIX - 1) == 0)
94 /* See if a symbol name is a reference to the procedure linkage table. */
96 #ifndef PLT_REF_PREFIX
97 #define PLT_REF_PREFIX "__PLT_"
100 #define IS_PLT_SYM(name) \
101 (strncmp (name, PLT_REF_PREFIX, sizeof PLT_REF_PREFIX - 1) == 0)
103 /* This string is used to generate specialized error messages. */
106 #define NEEDS_SHRLIB "__NEEDS_SHRLIB_"
109 /* This special symbol is a set vector that contains a list of
110 pointers to fixup tables. It will be present in any dynamicly
111 linked file. The linker generated fixup table should also be added
112 to the list, and it should always appear in the second slot (the
113 first one is a dummy with a magic number that is defined in
116 #ifndef SHARABLE_CONFLICTS
117 #define SHARABLE_CONFLICTS "__SHARABLE_CONFLICTS__"
120 /* We keep a list of fixups. The terminology is a bit strange, but
121 each fixup contains two 32 bit numbers. A regular fixup contains
122 an address and a pointer, and at runtime we should store the
123 address at the location pointed to by the pointer. A builtin fixup
124 contains two pointers, and we should read the address using one
125 pointer and store it at the location pointed to by the other
126 pointer. Builtin fixups come into play when we have duplicate
127 __GOT__ symbols for the same variable. The builtin fixup will copy
128 the GOT pointer from one over into the other. */
133 struct linux_link_hash_entry *h;
136 /* Nonzero if this is a jump instruction that needs to be fixed,
137 zero if this is just a pointer */
143 /* We don't need a special hash table entry structure, but we do need
144 to keep some information between linker passes, so we use a special
147 struct linux_link_hash_entry
149 struct aout_link_hash_entry root;
152 struct linux_link_hash_table
154 struct aout_link_hash_table root;
156 /* First dynamic object found in link. */
159 /* Number of fixups. */
162 /* Number of builtin fixups. */
163 size_t local_builtins;
165 /* List of fixups. */
166 struct fixup *fixup_list;
169 static struct bfd_hash_entry *linux_link_hash_newfunc
170 PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
171 static struct bfd_link_hash_table *linux_link_hash_table_create
173 static struct fixup *new_fixup
174 PARAMS ((struct bfd_link_info *, struct linux_link_hash_entry *,
176 static boolean linux_link_create_dynamic_sections
177 PARAMS ((bfd *, struct bfd_link_info *));
178 static boolean linux_add_one_symbol
179 PARAMS ((struct bfd_link_info *, bfd *, const char *, flagword, asection *,
180 bfd_vma, const char *, boolean, boolean,
181 struct bfd_link_hash_entry **));
182 static boolean linux_tally_symbols
183 PARAMS ((struct linux_link_hash_entry *, PTR));
184 static boolean linux_finish_dynamic_link
185 PARAMS ((bfd *, struct bfd_link_info *));
187 /* Routine to create an entry in an Linux link hash table. */
189 static struct bfd_hash_entry *
190 linux_link_hash_newfunc (entry, table, string)
191 struct bfd_hash_entry *entry;
192 struct bfd_hash_table *table;
195 struct linux_link_hash_entry *ret = (struct linux_link_hash_entry *) entry;
197 /* Allocate the structure if it has not already been allocated by a
199 if (ret == (struct linux_link_hash_entry *) NULL)
200 ret = ((struct linux_link_hash_entry *)
201 bfd_hash_allocate (table, sizeof (struct linux_link_hash_entry)));
203 return (struct bfd_hash_entry *) ret;
205 /* Call the allocation method of the superclass. */
206 ret = ((struct linux_link_hash_entry *)
207 NAME(aout,link_hash_newfunc) ((struct bfd_hash_entry *) ret,
211 /* Set local fields; there aren't any. */
214 return (struct bfd_hash_entry *) ret;
217 /* Create a Linux link hash table. */
219 static struct bfd_link_hash_table *
220 linux_link_hash_table_create (abfd)
223 struct linux_link_hash_table *ret;
225 ret = ((struct linux_link_hash_table *)
226 bfd_alloc (abfd, sizeof (struct linux_link_hash_table)));
227 if (ret == (struct linux_link_hash_table *) NULL)
229 bfd_set_error (bfd_error_no_memory);
230 return (struct bfd_link_hash_table *) NULL;
232 if (! NAME(aout,link_hash_table_init) (&ret->root, abfd,
233 linux_link_hash_newfunc))
236 return (struct bfd_link_hash_table *) NULL;
240 ret->fixup_count = 0;
241 ret->local_builtins = 0;
242 ret->fixup_list = NULL;
244 return &ret->root.root;
247 /* Look up an entry in a Linux link hash table. */
249 #define linux_link_hash_lookup(table, string, create, copy, follow) \
250 ((struct linux_link_hash_entry *) \
251 aout_link_hash_lookup (&(table)->root, (string), (create), (copy),\
254 /* Traverse a Linux link hash table. */
256 #define linux_link_hash_traverse(table, func, info) \
257 (aout_link_hash_traverse \
259 (boolean (*) PARAMS ((struct aout_link_hash_entry *, PTR))) (func), \
262 /* Get the Linux link hash table from the info structure. This is
265 #define linux_hash_table(p) ((struct linux_link_hash_table *) ((p)->hash))
267 /* Store the information for a new fixup. */
269 static struct fixup *
270 new_fixup (info, h, value, builtin)
271 struct bfd_link_info *info;
272 struct linux_link_hash_entry *h;
278 f = (struct fixup *) bfd_hash_allocate (&info->hash->table,
279 sizeof (struct fixup));
282 f->next = linux_hash_table (info)->fixup_list;
283 linux_hash_table (info)->fixup_list = f;
286 f->builtin = builtin;
288 ++linux_hash_table (info)->fixup_count;
292 /* We come here once we realize that we are going to link to a shared
293 library. We need to create a special section that contains the
294 fixup table, and we ultimately need to add a pointer to this into
295 the set vector for SHARABLE_CONFLICTS. At this point we do not
296 know the size of the section, but that's OK - we just need to
297 create it for now. */
300 linux_link_create_dynamic_sections (abfd, info)
302 struct bfd_link_info *info;
305 register asection *s;
307 /* Note that we set the SEC_IN_MEMORY flag. */
308 flags = SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY;
310 /* We choose to use the name ".linux-dynamic" for the fixup table.
312 s = bfd_make_section (abfd, ".linux-dynamic");
314 || ! bfd_set_section_flags (abfd, s, flags)
315 || ! bfd_set_section_alignment (abfd, s, 2))
323 /* Function to add a single symbol to the linker hash table. This is
324 a wrapper around _bfd_generic_link_add_one_symbol which handles the
325 tweaking needed for dynamic linking support. */
328 linux_add_one_symbol (info, abfd, name, flags, section, value, string,
329 copy, collect, hashp)
330 struct bfd_link_info *info;
339 struct bfd_link_hash_entry **hashp;
341 struct linux_link_hash_entry *h;
344 /* Look up and see if we already have this symbol in the hash table.
345 If we do, and the defining entry is from a shared library, we
346 need to create the dynamic sections.
348 FIXME: What if abfd->xvec != info->hash->creator? We may want to
349 be able to link Linux a.out and ELF objects together, but serious
350 confusion is possible. */
354 if (! info->relocateable
355 && linux_hash_table (info)->dynobj == NULL
356 && strcmp (name, SHARABLE_CONFLICTS) == 0
357 && (flags & BSF_CONSTRUCTOR) != 0
358 && abfd->xvec == info->hash->creator)
360 if (! linux_link_create_dynamic_sections (abfd, info))
362 linux_hash_table (info)->dynobj = abfd;
366 if (bfd_is_abs_section (section)
367 && abfd->xvec == info->hash->creator)
369 h = linux_link_hash_lookup (linux_hash_table (info), name, false,
372 && (h->root.root.type == bfd_link_hash_defined
373 || h->root.root.type == bfd_link_hash_defweak))
378 *hashp = (struct bfd_link_hash_entry *) h;
380 f = new_fixup (info, h, value, ! IS_PLT_SYM (name));
383 f->jump = IS_PLT_SYM (name);
389 /* Do the usual procedure for adding a symbol. */
390 if (! _bfd_generic_link_add_one_symbol (info, abfd, name, flags, section,
391 value, string, copy, collect,
395 /* Insert a pointer to our table in the set vector. The dynamic
396 linker requires this information */
401 /* Here we do our special thing to add the pointer to the
402 dynamic section in the SHARABLE_CONFLICTS set vector. */
403 s = bfd_get_section_by_name (linux_hash_table (info)->dynobj,
405 BFD_ASSERT (s != NULL);
407 if (! (_bfd_generic_link_add_one_symbol
408 (info, linux_hash_table (info)->dynobj, SHARABLE_CONFLICTS,
409 BSF_GLOBAL | BSF_CONSTRUCTOR, s, 0, NULL, false, false, NULL)))
416 /* We will crawl the hash table and come here for every global symbol.
417 We will examine each entry and see if there are indications that we
418 need to add a fixup. There are two possible cases - one is where
419 you have duplicate definitions of PLT or GOT symbols - these will
420 have already been caught and added as "builtin" fixups. If we find
421 that the corresponding non PLT/GOT symbol is also present, we
422 convert it to a regular fixup instead.
424 This function is called via linux_link_hash_traverse. */
427 linux_tally_symbols (h, data)
428 struct linux_link_hash_entry *h;
431 struct bfd_link_info *info = (struct bfd_link_info *) data;
432 struct fixup *f, *f1;
434 struct linux_link_hash_entry *h1, *h2;
437 if (h->root.root.type == bfd_link_hash_undefined
438 && strncmp (h->root.root.root.string, NEEDS_SHRLIB,
439 sizeof NEEDS_SHRLIB - 1) == 0)
445 name = h->root.root.root.string + sizeof NEEDS_SHRLIB - 1;
446 p = strrchr (name, '_');
448 alloc = (char *) bfd_malloc (strlen (name) + 1);
450 if (p == NULL || alloc == NULL)
451 (*_bfd_error_handler) ("Output file requires shared library `%s'\n",
455 strcpy (alloc, name);
456 p = strrchr (alloc, '_');
458 (*_bfd_error_handler)
459 ("Output file requires shared library `%s.so.%s'\n",
467 /* If this symbol is not a PLT/GOT, we do not even need to look at it */
468 is_plt = IS_PLT_SYM (h->root.root.root.string);
470 if (is_plt || IS_GOT_SYM (h->root.root.root.string))
472 /* Look up this symbol twice. Once just as a regular lookup,
473 and then again following all of the indirect links until we
474 reach a real symbol. */
475 h1 = linux_link_hash_lookup (linux_hash_table (info),
476 (h->root.root.root.string
477 + sizeof PLT_REF_PREFIX - 1),
479 /* h2 does not follow indirect symbols. */
480 h2 = linux_link_hash_lookup (linux_hash_table (info),
481 (h->root.root.root.string
482 + sizeof PLT_REF_PREFIX - 1),
483 false, false, false);
485 /* The real symbol must exist but if it is also an ABS symbol,
486 there is no need to have a fixup. This is because they both
487 came from the same library. If on the other hand, we had to
488 use an indirect symbol to get to the real symbol, we add the
489 fixup anyway, since there are cases where these symbols come
490 from different shared libraries */
492 && (((h1->root.root.type == bfd_link_hash_defined
493 || h1->root.root.type == bfd_link_hash_defweak)
494 && ! bfd_is_abs_section (h1->root.root.u.def.section))
495 || h2->root.root.type == bfd_link_hash_indirect))
497 /* See if there is a "builtin" fixup already present
498 involving this symbol. If so, convert it to a regular
499 fixup. In the end, this relaxes some of the requirements
500 about the order of performing fixups. */
502 for (f1 = linux_hash_table (info)->fixup_list;
506 if ((f1->h != h && f1->h != h1)
507 || (! f1->builtin && ! f1->jump))
512 && bfd_is_abs_section (h->root.root.u.def.section))
514 f = new_fixup (info, h1, f1->h->root.root.u.def.value, 0);
523 && bfd_is_abs_section (h->root.root.u.def.section))
525 f = new_fixup (info, h1, h->root.root.u.def.value, 0);
528 /* FIXME: No way to return error. */
535 /* Quick and dirty way of stripping these symbols from the
537 if (bfd_is_abs_section (h->root.root.u.def.section))
538 h->root.written = true;
544 /* This is called to set the size of the .linux-dynamic section is.
545 It is called by the Linux linker emulation before_allocation
546 routine. We have finished reading all of the input files, and now
547 we just scan the hash tables to find out how many additional fixups
551 bfd_m68klinux_size_dynamic_sections (output_bfd, info)
553 struct bfd_link_info *info;
558 if (output_bfd->xvec != &MY(vec))
561 /* First find the fixups... */
562 linux_link_hash_traverse (linux_hash_table (info),
566 /* If there are builtin fixups, leave room for a marker. This is
567 used by the dynamic linker so that it knows that all that follow
568 are builtin fixups instead of regular fixups. */
569 for (f = linux_hash_table (info)->fixup_list; f != NULL; f = f->next)
573 ++linux_hash_table (info)->fixup_count;
574 ++linux_hash_table (info)->local_builtins;
579 if (linux_hash_table (info)->dynobj == NULL)
581 if (linux_hash_table (info)->fixup_count > 0)
586 /* Allocate memory for our fixup table. We will fill it in later. */
587 s = bfd_get_section_by_name (linux_hash_table (info)->dynobj,
591 s->_raw_size = 8 + linux_hash_table (info)->fixup_count * 8;
592 s->contents = (bfd_byte *) bfd_alloc (output_bfd, s->_raw_size);
593 if (s->contents == NULL)
595 bfd_set_error (bfd_error_no_memory);
598 memset (s->contents, 0, (size_t) s->_raw_size);
604 /* We come here once we are ready to actually write the fixup table to
605 the output file. Scan the fixup tables and so forth and generate
606 the stuff we need. */
609 linux_finish_dynamic_link (output_bfd, info)
611 struct bfd_link_info *info;
613 asection *s, *os, *is;
614 bfd_byte *fixup_table;
615 struct linux_link_hash_entry *h;
617 unsigned int new_addr;
619 unsigned int fixups_written;
621 if (linux_hash_table (info)->dynobj == NULL)
624 s = bfd_get_section_by_name (linux_hash_table (info)->dynobj,
626 BFD_ASSERT (s != NULL);
627 os = s->output_section;
630 #ifdef LINUX_LINK_DEBUG
631 printf ("Fixup table file offset: %x VMA: %x\n",
632 os->filepos + s->output_offset,
633 os->vma + s->output_offset);
636 fixup_table = s->contents;
637 bfd_put_32 (output_bfd, linux_hash_table (info)->fixup_count, fixup_table);
640 /* Fill in fixup table. */
641 for (f = linux_hash_table (info)->fixup_list; f != NULL; f = f->next)
646 if (f->h->root.root.type != bfd_link_hash_defined
647 && f->h->root.root.type != bfd_link_hash_defweak)
649 (*_bfd_error_handler)
650 ("Symbol %s not defined for fixups\n",
651 f->h->root.root.root.string);
655 is = f->h->root.root.u.def.section;
656 section_offset = is->output_section->vma + is->output_offset;
657 new_addr = f->h->root.root.u.def.value + section_offset;
659 #ifdef LINUX_LINK_DEBUG
660 printf ("Fixup(%d) %s: %x %x\n",f->jump, f->h->root.root.string,
666 bfd_put_32 (output_bfd, new_addr, fixup_table);
668 bfd_put_32 (output_bfd, f->value + 2, fixup_table);
673 bfd_put_32 (output_bfd, new_addr, fixup_table);
675 bfd_put_32 (output_bfd, f->value, fixup_table);
681 if (linux_hash_table (info)->local_builtins != 0)
683 /* Special marker so we know to switch to the other type of fixup */
684 bfd_put_32 (output_bfd, 0, fixup_table);
686 bfd_put_32 (output_bfd, 0, fixup_table);
689 for (f = linux_hash_table (info)->fixup_list; f != NULL; f = f->next)
694 if (f->h->root.root.type != bfd_link_hash_defined
695 && f->h->root.root.type != bfd_link_hash_defweak)
697 (*_bfd_error_handler)
698 ("Symbol %s not defined for fixups\n",
699 f->h->root.root.root.string);
703 is = f->h->root.root.u.def.section;
704 section_offset = is->output_section->vma + is->output_offset;
705 new_addr = f->h->root.root.u.def.value + section_offset;
707 #ifdef LINUX_LINK_DEBUG
708 printf ("Fixup(B) %s: %x %x\n", f->h->root.root.string,
712 bfd_put_32 (output_bfd, new_addr, fixup_table);
714 bfd_put_32 (output_bfd, f->value, fixup_table);
720 if (linux_hash_table (info)->fixup_count != fixups_written)
722 (*_bfd_error_handler) ("Warning: fixup count mismatch\n");
723 while (linux_hash_table (info)->fixup_count > fixups_written)
725 bfd_put_32 (output_bfd, 0, fixup_table);
727 bfd_put_32 (output_bfd, 0, fixup_table);
733 h = linux_link_hash_lookup (linux_hash_table (info),
734 "__BUILTIN_FIXUPS__",
735 false, false, false);
738 && (h->root.root.type == bfd_link_hash_defined
739 || h->root.root.type == bfd_link_hash_defweak))
741 is = h->root.root.u.def.section;
742 section_offset = is->output_section->vma + is->output_offset;
743 new_addr = h->root.root.u.def.value + section_offset;
745 #ifdef LINUX_LINK_DEBUG
746 printf ("Builtin fixup table at %x\n", new_addr);
749 bfd_put_32 (output_bfd, new_addr, fixup_table);
752 bfd_put_32 (output_bfd, 0, fixup_table);
754 if (bfd_seek (output_bfd, os->filepos + s->output_offset, SEEK_SET) != 0)
757 if (bfd_write ((PTR) s->contents, 1, s->_raw_size, output_bfd)
764 #define MY_bfd_link_hash_table_create linux_link_hash_table_create
765 #define MY_add_one_symbol linux_add_one_symbol
766 #define MY_finish_dynamic_link linux_finish_dynamic_link
768 #define MY_zmagic_contiguous 1
770 #include "aout-target.h"