1 /* BFD back-end for linux flavored m68k a.out binaries.
2 Copyright 1992, 1993, 1994, 1995, 1996, 1997, 1999, 2000, 2001
3 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 2 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
21 #define TARGET_PAGE_SIZE 4096
22 #define ZMAGIC_DISK_BLOCK_SIZE 1024
23 #define SEGMENT_SIZE TARGET_PAGE_SIZE
24 #define TEXT_START_ADDR 0x0
25 #define N_SHARED_LIB(x) 0
26 #define BYTES_IN_WORD 4
28 #define MACHTYPE_OK(mtype) ((mtype) == M_68020 || (mtype) == M_UNKNOWN)
33 #include "aout/aout64.h"
34 #include "aout/stab_gnu.h"
36 #include "libaout.h" /* BFD a.out internal data structures */
38 #define TARGET_IS_BIG_ENDIAN_P
39 #define DEFAULT_ARCH bfd_arch_m68k
40 #define MY(OP) CAT(m68klinux_,OP)
41 #define TARGETNAME "a.out-m68k-linux"
43 extern const bfd_target
MY(vec
);
45 /* We always generate QMAGIC files in preference to ZMAGIC files. It
46 would be possible to make this a linker option, if that ever
49 static void MY_final_link_callback
50 PARAMS ((bfd
*, file_ptr
*, file_ptr
*, file_ptr
*));
51 static boolean m68klinux_bfd_final_link
52 PARAMS ((bfd
*, struct bfd_link_info
*));
53 static boolean m68klinux_write_object_contents
PARAMS ((bfd
*));
56 m68klinux_bfd_final_link (abfd
, info
)
58 struct bfd_link_info
*info
;
60 obj_aout_subformat (abfd
) = q_magic_format
;
61 return NAME(aout
,final_link
) (abfd
, info
, MY_final_link_callback
);
64 #define MY_bfd_final_link m68klinux_bfd_final_link
66 /* Set the machine type correctly. */
69 m68klinux_write_object_contents (abfd
)
72 struct external_exec exec_bytes
;
73 struct internal_exec
*execp
= exec_hdr (abfd
);
75 N_SET_MACHTYPE (*execp
, M_68020
);
77 obj_reloc_entry_size (abfd
) = RELOC_STD_SIZE
;
79 WRITE_HEADERS(abfd
, execp
);
84 #define MY_write_object_contents m68klinux_write_object_contents
86 /* Code to link against Linux a.out shared libraries. */
88 /* See if a symbol name is a reference to the global offset table. */
90 #ifndef GOT_REF_PREFIX
91 #define GOT_REF_PREFIX "__GOT_"
94 #define IS_GOT_SYM(name) \
95 (strncmp (name, GOT_REF_PREFIX, sizeof GOT_REF_PREFIX - 1) == 0)
97 /* See if a symbol name is a reference to the procedure linkage table. */
99 #ifndef PLT_REF_PREFIX
100 #define PLT_REF_PREFIX "__PLT_"
103 #define IS_PLT_SYM(name) \
104 (strncmp (name, PLT_REF_PREFIX, sizeof PLT_REF_PREFIX - 1) == 0)
106 /* This string is used to generate specialized error messages. */
109 #define NEEDS_SHRLIB "__NEEDS_SHRLIB_"
112 /* This special symbol is a set vector that contains a list of
113 pointers to fixup tables. It will be present in any dynamicly
114 linked file. The linker generated fixup table should also be added
115 to the list, and it should always appear in the second slot (the
116 first one is a dummy with a magic number that is defined in
119 #ifndef SHARABLE_CONFLICTS
120 #define SHARABLE_CONFLICTS "__SHARABLE_CONFLICTS__"
123 /* We keep a list of fixups. The terminology is a bit strange, but
124 each fixup contains two 32 bit numbers. A regular fixup contains
125 an address and a pointer, and at runtime we should store the
126 address at the location pointed to by the pointer. A builtin fixup
127 contains two pointers, and we should read the address using one
128 pointer and store it at the location pointed to by the other
129 pointer. Builtin fixups come into play when we have duplicate
130 __GOT__ symbols for the same variable. The builtin fixup will copy
131 the GOT pointer from one over into the other. */
136 struct linux_link_hash_entry
*h
;
139 /* Nonzero if this is a jump instruction that needs to be fixed,
140 zero if this is just a pointer */
146 /* We don't need a special hash table entry structure, but we do need
147 to keep some information between linker passes, so we use a special
150 struct linux_link_hash_entry
152 struct aout_link_hash_entry root
;
155 struct linux_link_hash_table
157 struct aout_link_hash_table root
;
159 /* First dynamic object found in link. */
162 /* Number of fixups. */
165 /* Number of builtin fixups. */
166 size_t local_builtins
;
168 /* List of fixups. */
169 struct fixup
*fixup_list
;
172 static struct bfd_hash_entry
*linux_link_hash_newfunc
173 PARAMS ((struct bfd_hash_entry
*, struct bfd_hash_table
*, const char *));
174 static struct bfd_link_hash_table
*linux_link_hash_table_create
176 static struct fixup
*new_fixup
177 PARAMS ((struct bfd_link_info
*, struct linux_link_hash_entry
*,
179 static boolean linux_link_create_dynamic_sections
180 PARAMS ((bfd
*, struct bfd_link_info
*));
181 static boolean linux_add_one_symbol
182 PARAMS ((struct bfd_link_info
*, bfd
*, const char *, flagword
, asection
*,
183 bfd_vma
, const char *, boolean
, boolean
,
184 struct bfd_link_hash_entry
**));
185 static boolean linux_tally_symbols
186 PARAMS ((struct linux_link_hash_entry
*, PTR
));
187 static boolean linux_finish_dynamic_link
188 PARAMS ((bfd
*, struct bfd_link_info
*));
190 /* Routine to create an entry in an Linux link hash table. */
192 static struct bfd_hash_entry
*
193 linux_link_hash_newfunc (entry
, table
, string
)
194 struct bfd_hash_entry
*entry
;
195 struct bfd_hash_table
*table
;
198 struct linux_link_hash_entry
*ret
= (struct linux_link_hash_entry
*) entry
;
200 /* Allocate the structure if it has not already been allocated by a
202 if (ret
== (struct linux_link_hash_entry
*) NULL
)
203 ret
= ((struct linux_link_hash_entry
*)
204 bfd_hash_allocate (table
, sizeof (struct linux_link_hash_entry
)));
206 return (struct bfd_hash_entry
*) ret
;
208 /* Call the allocation method of the superclass. */
209 ret
= ((struct linux_link_hash_entry
*)
210 NAME(aout
,link_hash_newfunc
) ((struct bfd_hash_entry
*) ret
,
214 /* Set local fields; there aren't any. */
217 return (struct bfd_hash_entry
*) ret
;
220 /* Create a Linux link hash table. */
222 static struct bfd_link_hash_table
*
223 linux_link_hash_table_create (abfd
)
226 struct linux_link_hash_table
*ret
;
227 bfd_size_type amt
= sizeof (struct linux_link_hash_table
);
229 ret
= (struct linux_link_hash_table
*) bfd_alloc (abfd
, amt
);
230 if (ret
== (struct linux_link_hash_table
*) NULL
)
232 bfd_set_error (bfd_error_no_memory
);
233 return (struct bfd_link_hash_table
*) NULL
;
235 if (! NAME(aout
,link_hash_table_init
) (&ret
->root
, abfd
,
236 linux_link_hash_newfunc
))
239 return (struct bfd_link_hash_table
*) NULL
;
243 ret
->fixup_count
= 0;
244 ret
->local_builtins
= 0;
245 ret
->fixup_list
= NULL
;
247 return &ret
->root
.root
;
250 /* Look up an entry in a Linux link hash table. */
252 #define linux_link_hash_lookup(table, string, create, copy, follow) \
253 ((struct linux_link_hash_entry *) \
254 aout_link_hash_lookup (&(table)->root, (string), (create), (copy),\
257 /* Traverse a Linux link hash table. */
259 #define linux_link_hash_traverse(table, func, info) \
260 (aout_link_hash_traverse \
262 (boolean (*) PARAMS ((struct aout_link_hash_entry *, PTR))) (func), \
265 /* Get the Linux link hash table from the info structure. This is
268 #define linux_hash_table(p) ((struct linux_link_hash_table *) ((p)->hash))
270 /* Store the information for a new fixup. */
272 static struct fixup
*
273 new_fixup (info
, h
, value
, builtin
)
274 struct bfd_link_info
*info
;
275 struct linux_link_hash_entry
*h
;
281 f
= (struct fixup
*) bfd_hash_allocate (&info
->hash
->table
,
282 sizeof (struct fixup
));
285 f
->next
= linux_hash_table (info
)->fixup_list
;
286 linux_hash_table (info
)->fixup_list
= f
;
289 f
->builtin
= builtin
;
291 ++linux_hash_table (info
)->fixup_count
;
295 /* We come here once we realize that we are going to link to a shared
296 library. We need to create a special section that contains the
297 fixup table, and we ultimately need to add a pointer to this into
298 the set vector for SHARABLE_CONFLICTS. At this point we do not
299 know the size of the section, but that's OK - we just need to
300 create it for now. */
303 linux_link_create_dynamic_sections (abfd
, info
)
305 struct bfd_link_info
*info ATTRIBUTE_UNUSED
;
308 register asection
*s
;
310 /* Note that we set the SEC_IN_MEMORY flag. */
311 flags
= SEC_ALLOC
| SEC_LOAD
| SEC_HAS_CONTENTS
| SEC_IN_MEMORY
;
313 /* We choose to use the name ".linux-dynamic" for the fixup table.
315 s
= bfd_make_section (abfd
, ".linux-dynamic");
317 || ! bfd_set_section_flags (abfd
, s
, flags
)
318 || ! bfd_set_section_alignment (abfd
, s
, 2))
326 /* Function to add a single symbol to the linker hash table. This is
327 a wrapper around _bfd_generic_link_add_one_symbol which handles the
328 tweaking needed for dynamic linking support. */
331 linux_add_one_symbol (info
, abfd
, name
, flags
, section
, value
, string
,
332 copy
, collect
, hashp
)
333 struct bfd_link_info
*info
;
342 struct bfd_link_hash_entry
**hashp
;
344 struct linux_link_hash_entry
*h
;
347 /* Look up and see if we already have this symbol in the hash table.
348 If we do, and the defining entry is from a shared library, we
349 need to create the dynamic sections.
351 FIXME: What if abfd->xvec != info->hash->creator? We may want to
352 be able to link Linux a.out and ELF objects together, but serious
353 confusion is possible. */
357 if (! info
->relocateable
358 && linux_hash_table (info
)->dynobj
== NULL
359 && strcmp (name
, SHARABLE_CONFLICTS
) == 0
360 && (flags
& BSF_CONSTRUCTOR
) != 0
361 && abfd
->xvec
== info
->hash
->creator
)
363 if (! linux_link_create_dynamic_sections (abfd
, info
))
365 linux_hash_table (info
)->dynobj
= abfd
;
369 if (bfd_is_abs_section (section
)
370 && abfd
->xvec
== info
->hash
->creator
)
372 h
= linux_link_hash_lookup (linux_hash_table (info
), name
, false,
375 && (h
->root
.root
.type
== bfd_link_hash_defined
376 || h
->root
.root
.type
== bfd_link_hash_defweak
))
381 *hashp
= (struct bfd_link_hash_entry
*) h
;
383 f
= new_fixup (info
, h
, value
, ! IS_PLT_SYM (name
));
386 f
->jump
= IS_PLT_SYM (name
);
392 /* Do the usual procedure for adding a symbol. */
393 if (! _bfd_generic_link_add_one_symbol (info
, abfd
, name
, flags
, section
,
394 value
, string
, copy
, collect
,
398 /* Insert a pointer to our table in the set vector. The dynamic
399 linker requires this information */
404 /* Here we do our special thing to add the pointer to the
405 dynamic section in the SHARABLE_CONFLICTS set vector. */
406 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
408 BFD_ASSERT (s
!= NULL
);
410 if (! (_bfd_generic_link_add_one_symbol
411 (info
, linux_hash_table (info
)->dynobj
, SHARABLE_CONFLICTS
,
412 BSF_GLOBAL
| BSF_CONSTRUCTOR
, s
, (bfd_vma
) 0, NULL
,
413 false, false, NULL
)))
420 /* We will crawl the hash table and come here for every global symbol.
421 We will examine each entry and see if there are indications that we
422 need to add a fixup. There are two possible cases - one is where
423 you have duplicate definitions of PLT or GOT symbols - these will
424 have already been caught and added as "builtin" fixups. If we find
425 that the corresponding non PLT/GOT symbol is also present, we
426 convert it to a regular fixup instead.
428 This function is called via linux_link_hash_traverse. */
431 linux_tally_symbols (h
, data
)
432 struct linux_link_hash_entry
*h
;
435 struct bfd_link_info
*info
= (struct bfd_link_info
*) data
;
436 struct fixup
*f
, *f1
;
438 struct linux_link_hash_entry
*h1
, *h2
;
441 if (h
->root
.root
.type
== bfd_link_hash_undefined
442 && strncmp (h
->root
.root
.root
.string
, NEEDS_SHRLIB
,
443 sizeof NEEDS_SHRLIB
- 1) == 0)
449 name
= h
->root
.root
.root
.string
+ sizeof NEEDS_SHRLIB
- 1;
450 p
= strrchr (name
, '_');
452 alloc
= (char *) bfd_malloc ((bfd_size_type
) strlen (name
) + 1);
454 if (p
== NULL
|| alloc
== NULL
)
455 (*_bfd_error_handler
) (_("Output file requires shared library `%s'\n"),
459 strcpy (alloc
, name
);
460 p
= strrchr (alloc
, '_');
462 (*_bfd_error_handler
)
463 (_("Output file requires shared library `%s.so.%s'\n"),
471 /* If this symbol is not a PLT/GOT, we do not even need to look at it */
472 is_plt
= IS_PLT_SYM (h
->root
.root
.root
.string
);
474 if (is_plt
|| IS_GOT_SYM (h
->root
.root
.root
.string
))
476 /* Look up this symbol twice. Once just as a regular lookup,
477 and then again following all of the indirect links until we
478 reach a real symbol. */
479 h1
= linux_link_hash_lookup (linux_hash_table (info
),
480 (h
->root
.root
.root
.string
481 + sizeof PLT_REF_PREFIX
- 1),
483 /* h2 does not follow indirect symbols. */
484 h2
= linux_link_hash_lookup (linux_hash_table (info
),
485 (h
->root
.root
.root
.string
486 + sizeof PLT_REF_PREFIX
- 1),
487 false, false, false);
489 /* The real symbol must exist but if it is also an ABS symbol,
490 there is no need to have a fixup. This is because they both
491 came from the same library. If on the other hand, we had to
492 use an indirect symbol to get to the real symbol, we add the
493 fixup anyway, since there are cases where these symbols come
494 from different shared libraries */
496 && (((h1
->root
.root
.type
== bfd_link_hash_defined
497 || h1
->root
.root
.type
== bfd_link_hash_defweak
)
498 && ! bfd_is_abs_section (h1
->root
.root
.u
.def
.section
))
499 || h2
->root
.root
.type
== bfd_link_hash_indirect
))
501 /* See if there is a "builtin" fixup already present
502 involving this symbol. If so, convert it to a regular
503 fixup. In the end, this relaxes some of the requirements
504 about the order of performing fixups. */
506 for (f1
= linux_hash_table (info
)->fixup_list
;
510 if ((f1
->h
!= h
&& f1
->h
!= h1
)
511 || (! f1
->builtin
&& ! f1
->jump
))
516 && bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
518 f
= new_fixup (info
, h1
, f1
->h
->root
.root
.u
.def
.value
, 0);
527 && bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
529 f
= new_fixup (info
, h1
, h
->root
.root
.u
.def
.value
, 0);
532 /* FIXME: No way to return error. */
539 /* Quick and dirty way of stripping these symbols from the
541 if (bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
542 h
->root
.written
= true;
548 /* This is called to set the size of the .linux-dynamic section is.
549 It is called by the Linux linker emulation before_allocation
550 routine. We have finished reading all of the input files, and now
551 we just scan the hash tables to find out how many additional fixups
555 bfd_m68klinux_size_dynamic_sections (output_bfd
, info
)
557 struct bfd_link_info
*info
;
562 if (output_bfd
->xvec
!= &MY(vec
))
565 /* First find the fixups... */
566 linux_link_hash_traverse (linux_hash_table (info
),
570 /* If there are builtin fixups, leave room for a marker. This is
571 used by the dynamic linker so that it knows that all that follow
572 are builtin fixups instead of regular fixups. */
573 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
577 ++linux_hash_table (info
)->fixup_count
;
578 ++linux_hash_table (info
)->local_builtins
;
583 if (linux_hash_table (info
)->dynobj
== NULL
)
585 if (linux_hash_table (info
)->fixup_count
> 0)
590 /* Allocate memory for our fixup table. We will fill it in later. */
591 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
595 s
->_raw_size
= linux_hash_table (info
)->fixup_count
+ 1;
597 s
->contents
= (bfd_byte
*) bfd_alloc (output_bfd
, s
->_raw_size
);
598 if (s
->contents
== NULL
)
600 bfd_set_error (bfd_error_no_memory
);
603 memset (s
->contents
, 0, (size_t) s
->_raw_size
);
609 /* We come here once we are ready to actually write the fixup table to
610 the output file. Scan the fixup tables and so forth and generate
611 the stuff we need. */
614 linux_finish_dynamic_link (output_bfd
, info
)
616 struct bfd_link_info
*info
;
618 asection
*s
, *os
, *is
;
619 bfd_byte
*fixup_table
;
620 struct linux_link_hash_entry
*h
;
622 unsigned int new_addr
;
624 unsigned int fixups_written
;
626 if (linux_hash_table (info
)->dynobj
== NULL
)
629 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
631 BFD_ASSERT (s
!= NULL
);
632 os
= s
->output_section
;
635 #ifdef LINUX_LINK_DEBUG
636 printf ("Fixup table file offset: %x VMA: %x\n",
637 os
->filepos
+ s
->output_offset
,
638 os
->vma
+ s
->output_offset
);
641 fixup_table
= s
->contents
;
642 bfd_put_32 (output_bfd
, (bfd_vma
) linux_hash_table (info
)->fixup_count
,
646 /* Fill in fixup table. */
647 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
652 if (f
->h
->root
.root
.type
!= bfd_link_hash_defined
653 && f
->h
->root
.root
.type
!= bfd_link_hash_defweak
)
655 (*_bfd_error_handler
)
656 (_("Symbol %s not defined for fixups\n"),
657 f
->h
->root
.root
.root
.string
);
661 is
= f
->h
->root
.root
.u
.def
.section
;
662 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
663 new_addr
= f
->h
->root
.root
.u
.def
.value
+ section_offset
;
665 #ifdef LINUX_LINK_DEBUG
666 printf ("Fixup(%d) %s: %x %x\n",f
->jump
, f
->h
->root
.root
.string
,
672 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
674 bfd_put_32 (output_bfd
, f
->value
+ 2, fixup_table
);
679 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
681 bfd_put_32 (output_bfd
, f
->value
, fixup_table
);
687 if (linux_hash_table (info
)->local_builtins
!= 0)
689 /* Special marker so we know to switch to the other type of fixup */
690 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
692 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
695 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
700 if (f
->h
->root
.root
.type
!= bfd_link_hash_defined
701 && f
->h
->root
.root
.type
!= bfd_link_hash_defweak
)
703 (*_bfd_error_handler
)
704 (_("Symbol %s not defined for fixups\n"),
705 f
->h
->root
.root
.root
.string
);
709 is
= f
->h
->root
.root
.u
.def
.section
;
710 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
711 new_addr
= f
->h
->root
.root
.u
.def
.value
+ section_offset
;
713 #ifdef LINUX_LINK_DEBUG
714 printf ("Fixup(B) %s: %x %x\n", f
->h
->root
.root
.string
,
718 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
720 bfd_put_32 (output_bfd
, f
->value
, fixup_table
);
726 if (linux_hash_table (info
)->fixup_count
!= fixups_written
)
728 (*_bfd_error_handler
) (_("Warning: fixup count mismatch\n"));
729 while (linux_hash_table (info
)->fixup_count
> fixups_written
)
731 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
733 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
739 h
= linux_link_hash_lookup (linux_hash_table (info
),
740 "__BUILTIN_FIXUPS__",
741 false, false, false);
744 && (h
->root
.root
.type
== bfd_link_hash_defined
745 || h
->root
.root
.type
== bfd_link_hash_defweak
))
747 is
= h
->root
.root
.u
.def
.section
;
748 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
749 new_addr
= h
->root
.root
.u
.def
.value
+ section_offset
;
751 #ifdef LINUX_LINK_DEBUG
752 printf ("Builtin fixup table at %x\n", new_addr
);
755 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
758 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
760 if (bfd_seek (output_bfd
, (file_ptr
) (os
->filepos
+ s
->output_offset
),
764 if (bfd_bwrite ((PTR
) s
->contents
, s
->_raw_size
, output_bfd
) != s
->_raw_size
)
770 #define MY_bfd_link_hash_table_create linux_link_hash_table_create
771 #define MY_add_one_symbol linux_add_one_symbol
772 #define MY_finish_dynamic_link linux_finish_dynamic_link
774 #define MY_zmagic_contiguous 1
776 #include "aout-target.h"