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
41 /* Do not "beautify" the CONCAT* macro args. Traditional C will not
42 remove whitespace added here, and thus will fail to concatenate
44 #define MY(OP) CONCAT2 (m68klinux_,OP)
45 #define TARGETNAME "a.out-m68k-linux"
47 extern const bfd_target
MY(vec
);
49 /* We always generate QMAGIC files in preference to ZMAGIC files. It
50 would be possible to make this a linker option, if that ever
53 static void MY_final_link_callback
54 PARAMS ((bfd
*, file_ptr
*, file_ptr
*, file_ptr
*));
55 static boolean m68klinux_bfd_final_link
56 PARAMS ((bfd
*, struct bfd_link_info
*));
57 static boolean m68klinux_write_object_contents
PARAMS ((bfd
*));
60 m68klinux_bfd_final_link (abfd
, info
)
62 struct bfd_link_info
*info
;
64 obj_aout_subformat (abfd
) = q_magic_format
;
65 return NAME(aout
,final_link
) (abfd
, info
, MY_final_link_callback
);
68 #define MY_bfd_final_link m68klinux_bfd_final_link
70 /* Set the machine type correctly. */
73 m68klinux_write_object_contents (abfd
)
76 struct external_exec exec_bytes
;
77 struct internal_exec
*execp
= exec_hdr (abfd
);
79 N_SET_MACHTYPE (*execp
, M_68020
);
81 obj_reloc_entry_size (abfd
) = RELOC_STD_SIZE
;
83 WRITE_HEADERS(abfd
, execp
);
88 #define MY_write_object_contents m68klinux_write_object_contents
90 /* Code to link against Linux a.out shared libraries. */
92 /* See if a symbol name is a reference to the global offset table. */
94 #ifndef GOT_REF_PREFIX
95 #define GOT_REF_PREFIX "__GOT_"
98 #define IS_GOT_SYM(name) \
99 (strncmp (name, GOT_REF_PREFIX, sizeof GOT_REF_PREFIX - 1) == 0)
101 /* See if a symbol name is a reference to the procedure linkage table. */
103 #ifndef PLT_REF_PREFIX
104 #define PLT_REF_PREFIX "__PLT_"
107 #define IS_PLT_SYM(name) \
108 (strncmp (name, PLT_REF_PREFIX, sizeof PLT_REF_PREFIX - 1) == 0)
110 /* This string is used to generate specialized error messages. */
113 #define NEEDS_SHRLIB "__NEEDS_SHRLIB_"
116 /* This special symbol is a set vector that contains a list of
117 pointers to fixup tables. It will be present in any dynamicly
118 linked file. The linker generated fixup table should also be added
119 to the list, and it should always appear in the second slot (the
120 first one is a dummy with a magic number that is defined in
123 #ifndef SHARABLE_CONFLICTS
124 #define SHARABLE_CONFLICTS "__SHARABLE_CONFLICTS__"
127 /* We keep a list of fixups. The terminology is a bit strange, but
128 each fixup contains two 32 bit numbers. A regular fixup contains
129 an address and a pointer, and at runtime we should store the
130 address at the location pointed to by the pointer. A builtin fixup
131 contains two pointers, and we should read the address using one
132 pointer and store it at the location pointed to by the other
133 pointer. Builtin fixups come into play when we have duplicate
134 __GOT__ symbols for the same variable. The builtin fixup will copy
135 the GOT pointer from one over into the other. */
140 struct linux_link_hash_entry
*h
;
143 /* Nonzero if this is a jump instruction that needs to be fixed,
144 zero if this is just a pointer */
150 /* We don't need a special hash table entry structure, but we do need
151 to keep some information between linker passes, so we use a special
154 struct linux_link_hash_entry
156 struct aout_link_hash_entry root
;
159 struct linux_link_hash_table
161 struct aout_link_hash_table root
;
163 /* First dynamic object found in link. */
166 /* Number of fixups. */
169 /* Number of builtin fixups. */
170 size_t local_builtins
;
172 /* List of fixups. */
173 struct fixup
*fixup_list
;
176 static struct bfd_hash_entry
*linux_link_hash_newfunc
177 PARAMS ((struct bfd_hash_entry
*, struct bfd_hash_table
*, const char *));
178 static struct bfd_link_hash_table
*linux_link_hash_table_create
180 static struct fixup
*new_fixup
181 PARAMS ((struct bfd_link_info
*, struct linux_link_hash_entry
*,
183 static boolean linux_link_create_dynamic_sections
184 PARAMS ((bfd
*, struct bfd_link_info
*));
185 static boolean linux_add_one_symbol
186 PARAMS ((struct bfd_link_info
*, bfd
*, const char *, flagword
, asection
*,
187 bfd_vma
, const char *, boolean
, boolean
,
188 struct bfd_link_hash_entry
**));
189 static boolean linux_tally_symbols
190 PARAMS ((struct linux_link_hash_entry
*, PTR
));
191 static boolean linux_finish_dynamic_link
192 PARAMS ((bfd
*, struct bfd_link_info
*));
194 /* Routine to create an entry in an Linux link hash table. */
196 static struct bfd_hash_entry
*
197 linux_link_hash_newfunc (entry
, table
, string
)
198 struct bfd_hash_entry
*entry
;
199 struct bfd_hash_table
*table
;
202 struct linux_link_hash_entry
*ret
= (struct linux_link_hash_entry
*) entry
;
204 /* Allocate the structure if it has not already been allocated by a
206 if (ret
== (struct linux_link_hash_entry
*) NULL
)
207 ret
= ((struct linux_link_hash_entry
*)
208 bfd_hash_allocate (table
, sizeof (struct linux_link_hash_entry
)));
210 return (struct bfd_hash_entry
*) ret
;
212 /* Call the allocation method of the superclass. */
213 ret
= ((struct linux_link_hash_entry
*)
214 NAME(aout
,link_hash_newfunc
) ((struct bfd_hash_entry
*) ret
,
218 /* Set local fields; there aren't any. */
221 return (struct bfd_hash_entry
*) ret
;
224 /* Create a Linux link hash table. */
226 static struct bfd_link_hash_table
*
227 linux_link_hash_table_create (abfd
)
230 struct linux_link_hash_table
*ret
;
231 bfd_size_type amt
= sizeof (struct linux_link_hash_table
);
233 ret
= (struct linux_link_hash_table
*) bfd_alloc (abfd
, amt
);
234 if (ret
== (struct linux_link_hash_table
*) NULL
)
236 bfd_set_error (bfd_error_no_memory
);
237 return (struct bfd_link_hash_table
*) NULL
;
239 if (! NAME(aout
,link_hash_table_init
) (&ret
->root
, abfd
,
240 linux_link_hash_newfunc
))
243 return (struct bfd_link_hash_table
*) NULL
;
247 ret
->fixup_count
= 0;
248 ret
->local_builtins
= 0;
249 ret
->fixup_list
= NULL
;
251 return &ret
->root
.root
;
254 /* Look up an entry in a Linux link hash table. */
256 #define linux_link_hash_lookup(table, string, create, copy, follow) \
257 ((struct linux_link_hash_entry *) \
258 aout_link_hash_lookup (&(table)->root, (string), (create), (copy),\
261 /* Traverse a Linux link hash table. */
263 #define linux_link_hash_traverse(table, func, info) \
264 (aout_link_hash_traverse \
266 (boolean (*) PARAMS ((struct aout_link_hash_entry *, PTR))) (func), \
269 /* Get the Linux link hash table from the info structure. This is
272 #define linux_hash_table(p) ((struct linux_link_hash_table *) ((p)->hash))
274 /* Store the information for a new fixup. */
276 static struct fixup
*
277 new_fixup (info
, h
, value
, builtin
)
278 struct bfd_link_info
*info
;
279 struct linux_link_hash_entry
*h
;
285 f
= (struct fixup
*) bfd_hash_allocate (&info
->hash
->table
,
286 sizeof (struct fixup
));
289 f
->next
= linux_hash_table (info
)->fixup_list
;
290 linux_hash_table (info
)->fixup_list
= f
;
293 f
->builtin
= builtin
;
295 ++linux_hash_table (info
)->fixup_count
;
299 /* We come here once we realize that we are going to link to a shared
300 library. We need to create a special section that contains the
301 fixup table, and we ultimately need to add a pointer to this into
302 the set vector for SHARABLE_CONFLICTS. At this point we do not
303 know the size of the section, but that's OK - we just need to
304 create it for now. */
307 linux_link_create_dynamic_sections (abfd
, info
)
309 struct bfd_link_info
*info ATTRIBUTE_UNUSED
;
312 register asection
*s
;
314 /* Note that we set the SEC_IN_MEMORY flag. */
315 flags
= SEC_ALLOC
| SEC_LOAD
| SEC_HAS_CONTENTS
| SEC_IN_MEMORY
;
317 /* We choose to use the name ".linux-dynamic" for the fixup table.
319 s
= bfd_make_section (abfd
, ".linux-dynamic");
321 || ! bfd_set_section_flags (abfd
, s
, flags
)
322 || ! bfd_set_section_alignment (abfd
, s
, 2))
330 /* Function to add a single symbol to the linker hash table. This is
331 a wrapper around _bfd_generic_link_add_one_symbol which handles the
332 tweaking needed for dynamic linking support. */
335 linux_add_one_symbol (info
, abfd
, name
, flags
, section
, value
, string
,
336 copy
, collect
, hashp
)
337 struct bfd_link_info
*info
;
346 struct bfd_link_hash_entry
**hashp
;
348 struct linux_link_hash_entry
*h
;
351 /* Look up and see if we already have this symbol in the hash table.
352 If we do, and the defining entry is from a shared library, we
353 need to create the dynamic sections.
355 FIXME: What if abfd->xvec != info->hash->creator? We may want to
356 be able to link Linux a.out and ELF objects together, but serious
357 confusion is possible. */
361 if (! info
->relocateable
362 && linux_hash_table (info
)->dynobj
== NULL
363 && strcmp (name
, SHARABLE_CONFLICTS
) == 0
364 && (flags
& BSF_CONSTRUCTOR
) != 0
365 && abfd
->xvec
== info
->hash
->creator
)
367 if (! linux_link_create_dynamic_sections (abfd
, info
))
369 linux_hash_table (info
)->dynobj
= abfd
;
373 if (bfd_is_abs_section (section
)
374 && abfd
->xvec
== info
->hash
->creator
)
376 h
= linux_link_hash_lookup (linux_hash_table (info
), name
, false,
379 && (h
->root
.root
.type
== bfd_link_hash_defined
380 || h
->root
.root
.type
== bfd_link_hash_defweak
))
385 *hashp
= (struct bfd_link_hash_entry
*) h
;
387 f
= new_fixup (info
, h
, value
, ! IS_PLT_SYM (name
));
390 f
->jump
= IS_PLT_SYM (name
);
396 /* Do the usual procedure for adding a symbol. */
397 if (! _bfd_generic_link_add_one_symbol (info
, abfd
, name
, flags
, section
,
398 value
, string
, copy
, collect
,
402 /* Insert a pointer to our table in the set vector. The dynamic
403 linker requires this information */
408 /* Here we do our special thing to add the pointer to the
409 dynamic section in the SHARABLE_CONFLICTS set vector. */
410 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
412 BFD_ASSERT (s
!= NULL
);
414 if (! (_bfd_generic_link_add_one_symbol
415 (info
, linux_hash_table (info
)->dynobj
, SHARABLE_CONFLICTS
,
416 BSF_GLOBAL
| BSF_CONSTRUCTOR
, s
, (bfd_vma
) 0, NULL
,
417 false, false, NULL
)))
424 /* We will crawl the hash table and come here for every global symbol.
425 We will examine each entry and see if there are indications that we
426 need to add a fixup. There are two possible cases - one is where
427 you have duplicate definitions of PLT or GOT symbols - these will
428 have already been caught and added as "builtin" fixups. If we find
429 that the corresponding non PLT/GOT symbol is also present, we
430 convert it to a regular fixup instead.
432 This function is called via linux_link_hash_traverse. */
435 linux_tally_symbols (h
, data
)
436 struct linux_link_hash_entry
*h
;
439 struct bfd_link_info
*info
= (struct bfd_link_info
*) data
;
440 struct fixup
*f
, *f1
;
442 struct linux_link_hash_entry
*h1
, *h2
;
445 if (h
->root
.root
.type
== bfd_link_hash_undefined
446 && strncmp (h
->root
.root
.root
.string
, NEEDS_SHRLIB
,
447 sizeof NEEDS_SHRLIB
- 1) == 0)
453 name
= h
->root
.root
.root
.string
+ sizeof NEEDS_SHRLIB
- 1;
454 p
= strrchr (name
, '_');
456 alloc
= (char *) bfd_malloc ((bfd_size_type
) strlen (name
) + 1);
458 if (p
== NULL
|| alloc
== NULL
)
459 (*_bfd_error_handler
) (_("Output file requires shared library `%s'\n"),
463 strcpy (alloc
, name
);
464 p
= strrchr (alloc
, '_');
466 (*_bfd_error_handler
)
467 (_("Output file requires shared library `%s.so.%s'\n"),
475 /* If this symbol is not a PLT/GOT, we do not even need to look at it */
476 is_plt
= IS_PLT_SYM (h
->root
.root
.root
.string
);
478 if (is_plt
|| IS_GOT_SYM (h
->root
.root
.root
.string
))
480 /* Look up this symbol twice. Once just as a regular lookup,
481 and then again following all of the indirect links until we
482 reach a real symbol. */
483 h1
= linux_link_hash_lookup (linux_hash_table (info
),
484 (h
->root
.root
.root
.string
485 + sizeof PLT_REF_PREFIX
- 1),
487 /* h2 does not follow indirect symbols. */
488 h2
= linux_link_hash_lookup (linux_hash_table (info
),
489 (h
->root
.root
.root
.string
490 + sizeof PLT_REF_PREFIX
- 1),
491 false, false, false);
493 /* The real symbol must exist but if it is also an ABS symbol,
494 there is no need to have a fixup. This is because they both
495 came from the same library. If on the other hand, we had to
496 use an indirect symbol to get to the real symbol, we add the
497 fixup anyway, since there are cases where these symbols come
498 from different shared libraries */
500 && (((h1
->root
.root
.type
== bfd_link_hash_defined
501 || h1
->root
.root
.type
== bfd_link_hash_defweak
)
502 && ! bfd_is_abs_section (h1
->root
.root
.u
.def
.section
))
503 || h2
->root
.root
.type
== bfd_link_hash_indirect
))
505 /* See if there is a "builtin" fixup already present
506 involving this symbol. If so, convert it to a regular
507 fixup. In the end, this relaxes some of the requirements
508 about the order of performing fixups. */
510 for (f1
= linux_hash_table (info
)->fixup_list
;
514 if ((f1
->h
!= h
&& f1
->h
!= h1
)
515 || (! f1
->builtin
&& ! f1
->jump
))
520 && bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
522 f
= new_fixup (info
, h1
, f1
->h
->root
.root
.u
.def
.value
, 0);
531 && bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
533 f
= new_fixup (info
, h1
, h
->root
.root
.u
.def
.value
, 0);
536 /* FIXME: No way to return error. */
543 /* Quick and dirty way of stripping these symbols from the
545 if (bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
546 h
->root
.written
= true;
552 /* This is called to set the size of the .linux-dynamic section is.
553 It is called by the Linux linker emulation before_allocation
554 routine. We have finished reading all of the input files, and now
555 we just scan the hash tables to find out how many additional fixups
559 bfd_m68klinux_size_dynamic_sections (output_bfd
, info
)
561 struct bfd_link_info
*info
;
566 if (output_bfd
->xvec
!= &MY(vec
))
569 /* First find the fixups... */
570 linux_link_hash_traverse (linux_hash_table (info
),
574 /* If there are builtin fixups, leave room for a marker. This is
575 used by the dynamic linker so that it knows that all that follow
576 are builtin fixups instead of regular fixups. */
577 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
581 ++linux_hash_table (info
)->fixup_count
;
582 ++linux_hash_table (info
)->local_builtins
;
587 if (linux_hash_table (info
)->dynobj
== NULL
)
589 if (linux_hash_table (info
)->fixup_count
> 0)
594 /* Allocate memory for our fixup table. We will fill it in later. */
595 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
599 s
->_raw_size
= linux_hash_table (info
)->fixup_count
+ 1;
601 s
->contents
= (bfd_byte
*) bfd_alloc (output_bfd
, s
->_raw_size
);
602 if (s
->contents
== NULL
)
604 bfd_set_error (bfd_error_no_memory
);
607 memset (s
->contents
, 0, (size_t) s
->_raw_size
);
613 /* We come here once we are ready to actually write the fixup table to
614 the output file. Scan the fixup tables and so forth and generate
615 the stuff we need. */
618 linux_finish_dynamic_link (output_bfd
, info
)
620 struct bfd_link_info
*info
;
622 asection
*s
, *os
, *is
;
623 bfd_byte
*fixup_table
;
624 struct linux_link_hash_entry
*h
;
626 unsigned int new_addr
;
628 unsigned int fixups_written
;
630 if (linux_hash_table (info
)->dynobj
== NULL
)
633 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
635 BFD_ASSERT (s
!= NULL
);
636 os
= s
->output_section
;
639 #ifdef LINUX_LINK_DEBUG
640 printf ("Fixup table file offset: %x VMA: %x\n",
641 os
->filepos
+ s
->output_offset
,
642 os
->vma
+ s
->output_offset
);
645 fixup_table
= s
->contents
;
646 bfd_put_32 (output_bfd
, (bfd_vma
) linux_hash_table (info
)->fixup_count
,
650 /* Fill in fixup table. */
651 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
656 if (f
->h
->root
.root
.type
!= bfd_link_hash_defined
657 && f
->h
->root
.root
.type
!= bfd_link_hash_defweak
)
659 (*_bfd_error_handler
)
660 (_("Symbol %s not defined for fixups\n"),
661 f
->h
->root
.root
.root
.string
);
665 is
= f
->h
->root
.root
.u
.def
.section
;
666 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
667 new_addr
= f
->h
->root
.root
.u
.def
.value
+ section_offset
;
669 #ifdef LINUX_LINK_DEBUG
670 printf ("Fixup(%d) %s: %x %x\n",f
->jump
, f
->h
->root
.root
.string
,
676 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
678 bfd_put_32 (output_bfd
, f
->value
+ 2, fixup_table
);
683 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
685 bfd_put_32 (output_bfd
, f
->value
, fixup_table
);
691 if (linux_hash_table (info
)->local_builtins
!= 0)
693 /* Special marker so we know to switch to the other type of fixup */
694 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
696 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
699 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
704 if (f
->h
->root
.root
.type
!= bfd_link_hash_defined
705 && f
->h
->root
.root
.type
!= bfd_link_hash_defweak
)
707 (*_bfd_error_handler
)
708 (_("Symbol %s not defined for fixups\n"),
709 f
->h
->root
.root
.root
.string
);
713 is
= f
->h
->root
.root
.u
.def
.section
;
714 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
715 new_addr
= f
->h
->root
.root
.u
.def
.value
+ section_offset
;
717 #ifdef LINUX_LINK_DEBUG
718 printf ("Fixup(B) %s: %x %x\n", f
->h
->root
.root
.string
,
722 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
724 bfd_put_32 (output_bfd
, f
->value
, fixup_table
);
730 if (linux_hash_table (info
)->fixup_count
!= fixups_written
)
732 (*_bfd_error_handler
) (_("Warning: fixup count mismatch\n"));
733 while (linux_hash_table (info
)->fixup_count
> fixups_written
)
735 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
737 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
743 h
= linux_link_hash_lookup (linux_hash_table (info
),
744 "__BUILTIN_FIXUPS__",
745 false, false, false);
748 && (h
->root
.root
.type
== bfd_link_hash_defined
749 || h
->root
.root
.type
== bfd_link_hash_defweak
))
751 is
= h
->root
.root
.u
.def
.section
;
752 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
753 new_addr
= h
->root
.root
.u
.def
.value
+ section_offset
;
755 #ifdef LINUX_LINK_DEBUG
756 printf ("Builtin fixup table at %x\n", new_addr
);
759 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
762 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
764 if (bfd_seek (output_bfd
, (file_ptr
) (os
->filepos
+ s
->output_offset
),
768 if (bfd_bwrite ((PTR
) s
->contents
, s
->_raw_size
, output_bfd
) != s
->_raw_size
)
774 #define MY_bfd_link_hash_table_create linux_link_hash_table_create
775 #define MY_add_one_symbol linux_add_one_symbol
776 #define MY_finish_dynamic_link linux_finish_dynamic_link
778 #define MY_zmagic_contiguous 1
780 #include "aout-target.h"