1 /* BFD back-end for linux flavored m68k a.out binaries.
2 Copyright (C) 1992, 93, 94, 95, 96, 1997, 1998 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
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
39 #define MY(OP) CAT(m68klinux_,OP)
40 #define TARGETNAME "a.out-m68k-linux"
42 extern const bfd_target
MY(vec
);
44 /* We always generate QMAGIC files in preference to ZMAGIC files. It
45 would be possible to make this a linker option, if that ever
48 static void MY_final_link_callback
49 PARAMS ((bfd
*, file_ptr
*, file_ptr
*, file_ptr
*));
50 static boolean m68klinux_bfd_final_link
51 PARAMS ((bfd
*, struct bfd_link_info
*));
52 static boolean m68klinux_write_object_contents
PARAMS ((bfd
*));
55 m68klinux_bfd_final_link (abfd
, info
)
57 struct bfd_link_info
*info
;
59 obj_aout_subformat (abfd
) = q_magic_format
;
60 return NAME(aout
,final_link
) (abfd
, info
, MY_final_link_callback
);
63 #define MY_bfd_final_link m68klinux_bfd_final_link
65 /* Set the machine type correctly. */
68 m68klinux_write_object_contents (abfd
)
71 struct external_exec exec_bytes
;
72 struct internal_exec
*execp
= exec_hdr (abfd
);
74 N_SET_MACHTYPE (*execp
, M_68020
);
76 obj_reloc_entry_size (abfd
) = RELOC_STD_SIZE
;
78 WRITE_HEADERS(abfd
, execp
);
83 #define MY_write_object_contents m68klinux_write_object_contents
85 /* Code to link against Linux a.out shared libraries. */
87 /* See if a symbol name is a reference to the global offset table. */
89 #ifndef GOT_REF_PREFIX
90 #define GOT_REF_PREFIX "__GOT_"
93 #define IS_GOT_SYM(name) \
94 (strncmp (name, GOT_REF_PREFIX, sizeof GOT_REF_PREFIX - 1) == 0)
96 /* See if a symbol name is a reference to the procedure linkage table. */
98 #ifndef PLT_REF_PREFIX
99 #define PLT_REF_PREFIX "__PLT_"
102 #define IS_PLT_SYM(name) \
103 (strncmp (name, PLT_REF_PREFIX, sizeof PLT_REF_PREFIX - 1) == 0)
105 /* This string is used to generate specialized error messages. */
108 #define NEEDS_SHRLIB "__NEEDS_SHRLIB_"
111 /* This special symbol is a set vector that contains a list of
112 pointers to fixup tables. It will be present in any dynamicly
113 linked file. The linker generated fixup table should also be added
114 to the list, and it should always appear in the second slot (the
115 first one is a dummy with a magic number that is defined in
118 #ifndef SHARABLE_CONFLICTS
119 #define SHARABLE_CONFLICTS "__SHARABLE_CONFLICTS__"
122 /* We keep a list of fixups. The terminology is a bit strange, but
123 each fixup contains two 32 bit numbers. A regular fixup contains
124 an address and a pointer, and at runtime we should store the
125 address at the location pointed to by the pointer. A builtin fixup
126 contains two pointers, and we should read the address using one
127 pointer and store it at the location pointed to by the other
128 pointer. Builtin fixups come into play when we have duplicate
129 __GOT__ symbols for the same variable. The builtin fixup will copy
130 the GOT pointer from one over into the other. */
135 struct linux_link_hash_entry
*h
;
138 /* Nonzero if this is a jump instruction that needs to be fixed,
139 zero if this is just a pointer */
145 /* We don't need a special hash table entry structure, but we do need
146 to keep some information between linker passes, so we use a special
149 struct linux_link_hash_entry
151 struct aout_link_hash_entry root
;
154 struct linux_link_hash_table
156 struct aout_link_hash_table root
;
158 /* First dynamic object found in link. */
161 /* Number of fixups. */
164 /* Number of builtin fixups. */
165 size_t local_builtins
;
167 /* List of fixups. */
168 struct fixup
*fixup_list
;
171 static struct bfd_hash_entry
*linux_link_hash_newfunc
172 PARAMS ((struct bfd_hash_entry
*, struct bfd_hash_table
*, const char *));
173 static struct bfd_link_hash_table
*linux_link_hash_table_create
175 static struct fixup
*new_fixup
176 PARAMS ((struct bfd_link_info
*, struct linux_link_hash_entry
*,
178 static boolean linux_link_create_dynamic_sections
179 PARAMS ((bfd
*, struct bfd_link_info
*));
180 static boolean linux_add_one_symbol
181 PARAMS ((struct bfd_link_info
*, bfd
*, const char *, flagword
, asection
*,
182 bfd_vma
, const char *, boolean
, boolean
,
183 struct bfd_link_hash_entry
**));
184 static boolean linux_tally_symbols
185 PARAMS ((struct linux_link_hash_entry
*, PTR
));
186 static boolean linux_finish_dynamic_link
187 PARAMS ((bfd
*, struct bfd_link_info
*));
189 /* Routine to create an entry in an Linux link hash table. */
191 static struct bfd_hash_entry
*
192 linux_link_hash_newfunc (entry
, table
, string
)
193 struct bfd_hash_entry
*entry
;
194 struct bfd_hash_table
*table
;
197 struct linux_link_hash_entry
*ret
= (struct linux_link_hash_entry
*) entry
;
199 /* Allocate the structure if it has not already been allocated by a
201 if (ret
== (struct linux_link_hash_entry
*) NULL
)
202 ret
= ((struct linux_link_hash_entry
*)
203 bfd_hash_allocate (table
, sizeof (struct linux_link_hash_entry
)));
205 return (struct bfd_hash_entry
*) ret
;
207 /* Call the allocation method of the superclass. */
208 ret
= ((struct linux_link_hash_entry
*)
209 NAME(aout
,link_hash_newfunc
) ((struct bfd_hash_entry
*) ret
,
213 /* Set local fields; there aren't any. */
216 return (struct bfd_hash_entry
*) ret
;
219 /* Create a Linux link hash table. */
221 static struct bfd_link_hash_table
*
222 linux_link_hash_table_create (abfd
)
225 struct linux_link_hash_table
*ret
;
227 ret
= ((struct linux_link_hash_table
*)
228 bfd_alloc (abfd
, sizeof (struct linux_link_hash_table
)));
229 if (ret
== (struct linux_link_hash_table
*) NULL
)
231 bfd_set_error (bfd_error_no_memory
);
232 return (struct bfd_link_hash_table
*) NULL
;
234 if (! NAME(aout
,link_hash_table_init
) (&ret
->root
, abfd
,
235 linux_link_hash_newfunc
))
238 return (struct bfd_link_hash_table
*) NULL
;
242 ret
->fixup_count
= 0;
243 ret
->local_builtins
= 0;
244 ret
->fixup_list
= NULL
;
246 return &ret
->root
.root
;
249 /* Look up an entry in a Linux link hash table. */
251 #define linux_link_hash_lookup(table, string, create, copy, follow) \
252 ((struct linux_link_hash_entry *) \
253 aout_link_hash_lookup (&(table)->root, (string), (create), (copy),\
256 /* Traverse a Linux link hash table. */
258 #define linux_link_hash_traverse(table, func, info) \
259 (aout_link_hash_traverse \
261 (boolean (*) PARAMS ((struct aout_link_hash_entry *, PTR))) (func), \
264 /* Get the Linux link hash table from the info structure. This is
267 #define linux_hash_table(p) ((struct linux_link_hash_table *) ((p)->hash))
269 /* Store the information for a new fixup. */
271 static struct fixup
*
272 new_fixup (info
, h
, value
, builtin
)
273 struct bfd_link_info
*info
;
274 struct linux_link_hash_entry
*h
;
280 f
= (struct fixup
*) bfd_hash_allocate (&info
->hash
->table
,
281 sizeof (struct fixup
));
284 f
->next
= linux_hash_table (info
)->fixup_list
;
285 linux_hash_table (info
)->fixup_list
= f
;
288 f
->builtin
= builtin
;
290 ++linux_hash_table (info
)->fixup_count
;
294 /* We come here once we realize that we are going to link to a shared
295 library. We need to create a special section that contains the
296 fixup table, and we ultimately need to add a pointer to this into
297 the set vector for SHARABLE_CONFLICTS. At this point we do not
298 know the size of the section, but that's OK - we just need to
299 create it for now. */
302 linux_link_create_dynamic_sections (abfd
, info
)
304 struct bfd_link_info
*info
;
307 register asection
*s
;
309 /* Note that we set the SEC_IN_MEMORY flag. */
310 flags
= SEC_ALLOC
| SEC_LOAD
| SEC_HAS_CONTENTS
| SEC_IN_MEMORY
;
312 /* We choose to use the name ".linux-dynamic" for the fixup table.
314 s
= bfd_make_section (abfd
, ".linux-dynamic");
316 || ! bfd_set_section_flags (abfd
, s
, flags
)
317 || ! bfd_set_section_alignment (abfd
, s
, 2))
325 /* Function to add a single symbol to the linker hash table. This is
326 a wrapper around _bfd_generic_link_add_one_symbol which handles the
327 tweaking needed for dynamic linking support. */
330 linux_add_one_symbol (info
, abfd
, name
, flags
, section
, value
, string
,
331 copy
, collect
, hashp
)
332 struct bfd_link_info
*info
;
341 struct bfd_link_hash_entry
**hashp
;
343 struct linux_link_hash_entry
*h
;
346 /* Look up and see if we already have this symbol in the hash table.
347 If we do, and the defining entry is from a shared library, we
348 need to create the dynamic sections.
350 FIXME: What if abfd->xvec != info->hash->creator? We may want to
351 be able to link Linux a.out and ELF objects together, but serious
352 confusion is possible. */
356 if (! info
->relocateable
357 && linux_hash_table (info
)->dynobj
== NULL
358 && strcmp (name
, SHARABLE_CONFLICTS
) == 0
359 && (flags
& BSF_CONSTRUCTOR
) != 0
360 && abfd
->xvec
== info
->hash
->creator
)
362 if (! linux_link_create_dynamic_sections (abfd
, info
))
364 linux_hash_table (info
)->dynobj
= abfd
;
368 if (bfd_is_abs_section (section
)
369 && abfd
->xvec
== info
->hash
->creator
)
371 h
= linux_link_hash_lookup (linux_hash_table (info
), name
, false,
374 && (h
->root
.root
.type
== bfd_link_hash_defined
375 || h
->root
.root
.type
== bfd_link_hash_defweak
))
380 *hashp
= (struct bfd_link_hash_entry
*) h
;
382 f
= new_fixup (info
, h
, value
, ! IS_PLT_SYM (name
));
385 f
->jump
= IS_PLT_SYM (name
);
391 /* Do the usual procedure for adding a symbol. */
392 if (! _bfd_generic_link_add_one_symbol (info
, abfd
, name
, flags
, section
,
393 value
, string
, copy
, collect
,
397 /* Insert a pointer to our table in the set vector. The dynamic
398 linker requires this information */
403 /* Here we do our special thing to add the pointer to the
404 dynamic section in the SHARABLE_CONFLICTS set vector. */
405 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
407 BFD_ASSERT (s
!= NULL
);
409 if (! (_bfd_generic_link_add_one_symbol
410 (info
, linux_hash_table (info
)->dynobj
, SHARABLE_CONFLICTS
,
411 BSF_GLOBAL
| BSF_CONSTRUCTOR
, s
, 0, NULL
, false, false, NULL
)))
418 /* We will crawl the hash table and come here for every global symbol.
419 We will examine each entry and see if there are indications that we
420 need to add a fixup. There are two possible cases - one is where
421 you have duplicate definitions of PLT or GOT symbols - these will
422 have already been caught and added as "builtin" fixups. If we find
423 that the corresponding non PLT/GOT symbol is also present, we
424 convert it to a regular fixup instead.
426 This function is called via linux_link_hash_traverse. */
429 linux_tally_symbols (h
, data
)
430 struct linux_link_hash_entry
*h
;
433 struct bfd_link_info
*info
= (struct bfd_link_info
*) data
;
434 struct fixup
*f
, *f1
;
436 struct linux_link_hash_entry
*h1
, *h2
;
439 if (h
->root
.root
.type
== bfd_link_hash_undefined
440 && strncmp (h
->root
.root
.root
.string
, NEEDS_SHRLIB
,
441 sizeof NEEDS_SHRLIB
- 1) == 0)
447 name
= h
->root
.root
.root
.string
+ sizeof NEEDS_SHRLIB
- 1;
448 p
= strrchr (name
, '_');
450 alloc
= (char *) bfd_malloc (strlen (name
) + 1);
452 if (p
== NULL
|| alloc
== NULL
)
453 (*_bfd_error_handler
) (_("Output file requires shared library `%s'\n"),
457 strcpy (alloc
, name
);
458 p
= strrchr (alloc
, '_');
460 (*_bfd_error_handler
)
461 (_("Output file requires shared library `%s.so.%s'\n"),
469 /* If this symbol is not a PLT/GOT, we do not even need to look at it */
470 is_plt
= IS_PLT_SYM (h
->root
.root
.root
.string
);
472 if (is_plt
|| IS_GOT_SYM (h
->root
.root
.root
.string
))
474 /* Look up this symbol twice. Once just as a regular lookup,
475 and then again following all of the indirect links until we
476 reach a real symbol. */
477 h1
= linux_link_hash_lookup (linux_hash_table (info
),
478 (h
->root
.root
.root
.string
479 + sizeof PLT_REF_PREFIX
- 1),
481 /* h2 does not follow indirect symbols. */
482 h2
= linux_link_hash_lookup (linux_hash_table (info
),
483 (h
->root
.root
.root
.string
484 + sizeof PLT_REF_PREFIX
- 1),
485 false, false, false);
487 /* The real symbol must exist but if it is also an ABS symbol,
488 there is no need to have a fixup. This is because they both
489 came from the same library. If on the other hand, we had to
490 use an indirect symbol to get to the real symbol, we add the
491 fixup anyway, since there are cases where these symbols come
492 from different shared libraries */
494 && (((h1
->root
.root
.type
== bfd_link_hash_defined
495 || h1
->root
.root
.type
== bfd_link_hash_defweak
)
496 && ! bfd_is_abs_section (h1
->root
.root
.u
.def
.section
))
497 || h2
->root
.root
.type
== bfd_link_hash_indirect
))
499 /* See if there is a "builtin" fixup already present
500 involving this symbol. If so, convert it to a regular
501 fixup. In the end, this relaxes some of the requirements
502 about the order of performing fixups. */
504 for (f1
= linux_hash_table (info
)->fixup_list
;
508 if ((f1
->h
!= h
&& f1
->h
!= h1
)
509 || (! f1
->builtin
&& ! f1
->jump
))
514 && bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
516 f
= new_fixup (info
, h1
, f1
->h
->root
.root
.u
.def
.value
, 0);
525 && bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
527 f
= new_fixup (info
, h1
, h
->root
.root
.u
.def
.value
, 0);
530 /* FIXME: No way to return error. */
537 /* Quick and dirty way of stripping these symbols from the
539 if (bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
540 h
->root
.written
= true;
546 /* This is called to set the size of the .linux-dynamic section is.
547 It is called by the Linux linker emulation before_allocation
548 routine. We have finished reading all of the input files, and now
549 we just scan the hash tables to find out how many additional fixups
553 bfd_m68klinux_size_dynamic_sections (output_bfd
, info
)
555 struct bfd_link_info
*info
;
560 if (output_bfd
->xvec
!= &MY(vec
))
563 /* First find the fixups... */
564 linux_link_hash_traverse (linux_hash_table (info
),
568 /* If there are builtin fixups, leave room for a marker. This is
569 used by the dynamic linker so that it knows that all that follow
570 are builtin fixups instead of regular fixups. */
571 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
575 ++linux_hash_table (info
)->fixup_count
;
576 ++linux_hash_table (info
)->local_builtins
;
581 if (linux_hash_table (info
)->dynobj
== NULL
)
583 if (linux_hash_table (info
)->fixup_count
> 0)
588 /* Allocate memory for our fixup table. We will fill it in later. */
589 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
593 s
->_raw_size
= 8 + linux_hash_table (info
)->fixup_count
* 8;
594 s
->contents
= (bfd_byte
*) bfd_alloc (output_bfd
, s
->_raw_size
);
595 if (s
->contents
== NULL
)
597 bfd_set_error (bfd_error_no_memory
);
600 memset (s
->contents
, 0, (size_t) s
->_raw_size
);
606 /* We come here once we are ready to actually write the fixup table to
607 the output file. Scan the fixup tables and so forth and generate
608 the stuff we need. */
611 linux_finish_dynamic_link (output_bfd
, info
)
613 struct bfd_link_info
*info
;
615 asection
*s
, *os
, *is
;
616 bfd_byte
*fixup_table
;
617 struct linux_link_hash_entry
*h
;
619 unsigned int new_addr
;
621 unsigned int fixups_written
;
623 if (linux_hash_table (info
)->dynobj
== NULL
)
626 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
628 BFD_ASSERT (s
!= NULL
);
629 os
= s
->output_section
;
632 #ifdef LINUX_LINK_DEBUG
633 printf ("Fixup table file offset: %x VMA: %x\n",
634 os
->filepos
+ s
->output_offset
,
635 os
->vma
+ s
->output_offset
);
638 fixup_table
= s
->contents
;
639 bfd_put_32 (output_bfd
, linux_hash_table (info
)->fixup_count
, fixup_table
);
642 /* Fill in fixup table. */
643 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
648 if (f
->h
->root
.root
.type
!= bfd_link_hash_defined
649 && f
->h
->root
.root
.type
!= bfd_link_hash_defweak
)
651 (*_bfd_error_handler
)
652 (_("Symbol %s not defined for fixups\n"),
653 f
->h
->root
.root
.root
.string
);
657 is
= f
->h
->root
.root
.u
.def
.section
;
658 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
659 new_addr
= f
->h
->root
.root
.u
.def
.value
+ section_offset
;
661 #ifdef LINUX_LINK_DEBUG
662 printf ("Fixup(%d) %s: %x %x\n",f
->jump
, f
->h
->root
.root
.string
,
668 bfd_put_32 (output_bfd
, new_addr
, fixup_table
);
670 bfd_put_32 (output_bfd
, f
->value
+ 2, fixup_table
);
675 bfd_put_32 (output_bfd
, new_addr
, fixup_table
);
677 bfd_put_32 (output_bfd
, f
->value
, fixup_table
);
683 if (linux_hash_table (info
)->local_builtins
!= 0)
685 /* Special marker so we know to switch to the other type of fixup */
686 bfd_put_32 (output_bfd
, 0, fixup_table
);
688 bfd_put_32 (output_bfd
, 0, fixup_table
);
691 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
696 if (f
->h
->root
.root
.type
!= bfd_link_hash_defined
697 && f
->h
->root
.root
.type
!= bfd_link_hash_defweak
)
699 (*_bfd_error_handler
)
700 (_("Symbol %s not defined for fixups\n"),
701 f
->h
->root
.root
.root
.string
);
705 is
= f
->h
->root
.root
.u
.def
.section
;
706 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
707 new_addr
= f
->h
->root
.root
.u
.def
.value
+ section_offset
;
709 #ifdef LINUX_LINK_DEBUG
710 printf ("Fixup(B) %s: %x %x\n", f
->h
->root
.root
.string
,
714 bfd_put_32 (output_bfd
, new_addr
, fixup_table
);
716 bfd_put_32 (output_bfd
, f
->value
, fixup_table
);
722 if (linux_hash_table (info
)->fixup_count
!= fixups_written
)
724 (*_bfd_error_handler
) (_("Warning: fixup count mismatch\n"));
725 while (linux_hash_table (info
)->fixup_count
> fixups_written
)
727 bfd_put_32 (output_bfd
, 0, fixup_table
);
729 bfd_put_32 (output_bfd
, 0, fixup_table
);
735 h
= linux_link_hash_lookup (linux_hash_table (info
),
736 "__BUILTIN_FIXUPS__",
737 false, false, false);
740 && (h
->root
.root
.type
== bfd_link_hash_defined
741 || h
->root
.root
.type
== bfd_link_hash_defweak
))
743 is
= h
->root
.root
.u
.def
.section
;
744 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
745 new_addr
= h
->root
.root
.u
.def
.value
+ section_offset
;
747 #ifdef LINUX_LINK_DEBUG
748 printf ("Builtin fixup table at %x\n", new_addr
);
751 bfd_put_32 (output_bfd
, new_addr
, fixup_table
);
754 bfd_put_32 (output_bfd
, 0, fixup_table
);
756 if (bfd_seek (output_bfd
, os
->filepos
+ s
->output_offset
, SEEK_SET
) != 0)
759 if (bfd_write ((PTR
) s
->contents
, 1, s
->_raw_size
, output_bfd
)
766 #define MY_bfd_link_hash_table_create linux_link_hash_table_create
767 #define MY_add_one_symbol linux_add_one_symbol
768 #define MY_finish_dynamic_link linux_finish_dynamic_link
770 #define MY_zmagic_contiguous 1
772 #include "aout-target.h"