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, 2006, 2007, 2008 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
26 #define N_SHARED_LIB(x) 0
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 bfd_boolean m68klinux_bfd_final_link
56 PARAMS ((bfd
*, struct bfd_link_info
*));
57 static bfd_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) (CONST_STRNEQ (name, GOT_REF_PREFIX))
100 /* See if a symbol name is a reference to the procedure linkage table. */
102 #ifndef PLT_REF_PREFIX
103 #define PLT_REF_PREFIX "__PLT_"
106 #define IS_PLT_SYM(name) (CONST_STRNEQ (name, PLT_REF_PREFIX))
108 /* This string is used to generate specialized error messages. */
111 #define NEEDS_SHRLIB "__NEEDS_SHRLIB_"
114 /* This special symbol is a set vector that contains a list of
115 pointers to fixup tables. It will be present in any dynamically
116 linked file. The linker generated fixup table should also be added
117 to the list, and it should always appear in the second slot (the
118 first one is a dummy with a magic number that is defined in
121 #ifndef SHARABLE_CONFLICTS
122 #define SHARABLE_CONFLICTS "__SHARABLE_CONFLICTS__"
125 /* We keep a list of fixups. The terminology is a bit strange, but
126 each fixup contains two 32 bit numbers. A regular fixup contains
127 an address and a pointer, and at runtime we should store the
128 address at the location pointed to by the pointer. A builtin fixup
129 contains two pointers, and we should read the address using one
130 pointer and store it at the location pointed to by the other
131 pointer. Builtin fixups come into play when we have duplicate
132 __GOT__ symbols for the same variable. The builtin fixup will copy
133 the GOT pointer from one over into the other. */
138 struct linux_link_hash_entry
*h
;
141 /* Nonzero if this is a jump instruction that needs to be fixed,
142 zero if this is just a pointer */
148 /* We don't need a special hash table entry structure, but we do need
149 to keep some information between linker passes, so we use a special
152 struct linux_link_hash_entry
154 struct aout_link_hash_entry root
;
157 struct linux_link_hash_table
159 struct aout_link_hash_table root
;
161 /* First dynamic object found in link. */
164 /* Number of fixups. */
167 /* Number of builtin fixups. */
168 size_t local_builtins
;
170 /* List of fixups. */
171 struct fixup
*fixup_list
;
174 static struct bfd_hash_entry
*linux_link_hash_newfunc
175 PARAMS ((struct bfd_hash_entry
*, struct bfd_hash_table
*, const char *));
176 static struct bfd_link_hash_table
*linux_link_hash_table_create
178 static struct fixup
*new_fixup
179 PARAMS ((struct bfd_link_info
*, struct linux_link_hash_entry
*,
181 static bfd_boolean linux_link_create_dynamic_sections
182 PARAMS ((bfd
*, struct bfd_link_info
*));
183 static bfd_boolean linux_add_one_symbol
184 PARAMS ((struct bfd_link_info
*, bfd
*, const char *, flagword
, asection
*,
185 bfd_vma
, const char *, bfd_boolean
, bfd_boolean
,
186 struct bfd_link_hash_entry
**));
187 static bfd_boolean linux_tally_symbols
188 PARAMS ((struct linux_link_hash_entry
*, PTR
));
189 static bfd_boolean linux_finish_dynamic_link
190 PARAMS ((bfd
*, struct bfd_link_info
*));
192 /* Routine to create an entry in an Linux link hash table. */
194 static struct bfd_hash_entry
*
195 linux_link_hash_newfunc (entry
, table
, string
)
196 struct bfd_hash_entry
*entry
;
197 struct bfd_hash_table
*table
;
200 struct linux_link_hash_entry
*ret
= (struct linux_link_hash_entry
*) entry
;
202 /* Allocate the structure if it has not already been allocated by a
204 if (ret
== (struct linux_link_hash_entry
*) NULL
)
205 ret
= ((struct linux_link_hash_entry
*)
206 bfd_hash_allocate (table
, sizeof (struct linux_link_hash_entry
)));
208 return (struct bfd_hash_entry
*) ret
;
210 /* Call the allocation method of the superclass. */
211 ret
= ((struct linux_link_hash_entry
*)
212 NAME(aout
,link_hash_newfunc
) ((struct bfd_hash_entry
*) ret
,
216 /* Set local fields; there aren't any. */
219 return (struct bfd_hash_entry
*) ret
;
222 /* Create a Linux link hash table. */
224 static struct bfd_link_hash_table
*
225 linux_link_hash_table_create (abfd
)
228 struct linux_link_hash_table
*ret
;
229 bfd_size_type amt
= sizeof (struct linux_link_hash_table
);
231 ret
= (struct linux_link_hash_table
*) bfd_malloc (amt
);
232 if (ret
== (struct linux_link_hash_table
*) NULL
)
234 bfd_set_error (bfd_error_no_memory
);
235 return (struct bfd_link_hash_table
*) NULL
;
237 if (!NAME(aout
,link_hash_table_init
) (&ret
->root
, abfd
,
238 linux_link_hash_newfunc
,
239 sizeof (struct linux_link_hash_entry
)))
242 return (struct bfd_link_hash_table
*) NULL
;
246 ret
->fixup_count
= 0;
247 ret
->local_builtins
= 0;
248 ret
->fixup_list
= NULL
;
250 return &ret
->root
.root
;
253 /* Look up an entry in a Linux link hash table. */
255 #define linux_link_hash_lookup(table, string, create, copy, follow) \
256 ((struct linux_link_hash_entry *) \
257 aout_link_hash_lookup (&(table)->root, (string), (create), (copy),\
260 /* Traverse a Linux link hash table. */
262 #define linux_link_hash_traverse(table, func, info) \
263 (aout_link_hash_traverse \
265 (bfd_boolean (*) PARAMS ((struct aout_link_hash_entry *, PTR))) (func), \
268 /* Get the Linux link hash table from the info structure. This is
271 #define linux_hash_table(p) ((struct linux_link_hash_table *) ((p)->hash))
273 /* Store the information for a new fixup. */
275 static struct fixup
*
276 new_fixup (info
, h
, value
, builtin
)
277 struct bfd_link_info
*info
;
278 struct linux_link_hash_entry
*h
;
284 f
= (struct fixup
*) bfd_hash_allocate (&info
->hash
->table
,
285 sizeof (struct fixup
));
288 f
->next
= linux_hash_table (info
)->fixup_list
;
289 linux_hash_table (info
)->fixup_list
= f
;
292 f
->builtin
= builtin
;
294 ++linux_hash_table (info
)->fixup_count
;
298 /* We come here once we realize that we are going to link to a shared
299 library. We need to create a special section that contains the
300 fixup table, and we ultimately need to add a pointer to this into
301 the set vector for SHARABLE_CONFLICTS. At this point we do not
302 know the size of the section, but that's OK - we just need to
303 create it for now. */
306 linux_link_create_dynamic_sections (abfd
, info
)
308 struct bfd_link_info
*info ATTRIBUTE_UNUSED
;
311 register asection
*s
;
313 /* Note that we set the SEC_IN_MEMORY flag. */
314 flags
= SEC_ALLOC
| SEC_LOAD
| SEC_HAS_CONTENTS
| SEC_IN_MEMORY
;
316 /* We choose to use the name ".linux-dynamic" for the fixup table.
318 s
= bfd_make_section_with_flags (abfd
, ".linux-dynamic", flags
);
320 || ! bfd_set_section_alignment (abfd
, s
, 2))
328 /* Function to add a single symbol to the linker hash table. This is
329 a wrapper around _bfd_generic_link_add_one_symbol which handles the
330 tweaking needed for dynamic linking support. */
333 linux_add_one_symbol (info
, abfd
, name
, flags
, section
, value
, string
,
334 copy
, collect
, hashp
)
335 struct bfd_link_info
*info
;
344 struct bfd_link_hash_entry
**hashp
;
346 struct linux_link_hash_entry
*h
;
349 /* Look up and see if we already have this symbol in the hash table.
350 If we do, and the defining entry is from a shared library, we
351 need to create the dynamic sections.
353 FIXME: What if abfd->xvec != info->output_bfd->xvec? We may
354 want to be able to link Linux a.out and ELF objects together,
355 but serious confusion is possible. */
359 if (! info
->relocatable
360 && linux_hash_table (info
)->dynobj
== NULL
361 && strcmp (name
, SHARABLE_CONFLICTS
) == 0
362 && (flags
& BSF_CONSTRUCTOR
) != 0
363 && abfd
->xvec
== info
->output_bfd
->xvec
)
365 if (! linux_link_create_dynamic_sections (abfd
, info
))
367 linux_hash_table (info
)->dynobj
= abfd
;
371 if (bfd_is_abs_section (section
)
372 && abfd
->xvec
== info
->output_bfd
->xvec
)
374 h
= linux_link_hash_lookup (linux_hash_table (info
), name
, FALSE
,
377 && (h
->root
.root
.type
== bfd_link_hash_defined
378 || h
->root
.root
.type
== bfd_link_hash_defweak
))
383 *hashp
= (struct bfd_link_hash_entry
*) h
;
385 f
= new_fixup (info
, h
, value
, ! IS_PLT_SYM (name
));
388 f
->jump
= IS_PLT_SYM (name
);
394 /* Do the usual procedure for adding a symbol. */
395 if (! _bfd_generic_link_add_one_symbol (info
, abfd
, name
, flags
, section
,
396 value
, string
, copy
, collect
,
400 /* Insert a pointer to our table in the set vector. The dynamic
401 linker requires this information */
406 /* Here we do our special thing to add the pointer to the
407 dynamic section in the SHARABLE_CONFLICTS set vector. */
408 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
410 BFD_ASSERT (s
!= NULL
);
412 if (! (_bfd_generic_link_add_one_symbol
413 (info
, linux_hash_table (info
)->dynobj
, SHARABLE_CONFLICTS
,
414 BSF_GLOBAL
| BSF_CONSTRUCTOR
, s
, (bfd_vma
) 0, NULL
,
415 FALSE
, FALSE
, NULL
)))
422 /* We will crawl the hash table and come here for every global symbol.
423 We will examine each entry and see if there are indications that we
424 need to add a fixup. There are two possible cases - one is where
425 you have duplicate definitions of PLT or GOT symbols - these will
426 have already been caught and added as "builtin" fixups. If we find
427 that the corresponding non PLT/GOT symbol is also present, we
428 convert it to a regular fixup instead.
430 This function is called via linux_link_hash_traverse. */
433 linux_tally_symbols (h
, data
)
434 struct linux_link_hash_entry
*h
;
437 struct bfd_link_info
*info
= (struct bfd_link_info
*) data
;
438 struct fixup
*f
, *f1
;
440 struct linux_link_hash_entry
*h1
, *h2
;
443 if (h
->root
.root
.type
== bfd_link_hash_warning
)
444 h
= (struct linux_link_hash_entry
*) h
->root
.root
.u
.i
.link
;
446 if (h
->root
.root
.type
== bfd_link_hash_undefined
447 && CONST_STRNEQ (h
->root
.root
.root
.string
, NEEDS_SHRLIB
))
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
->size
= linux_hash_table (info
)->fixup_count
+ 1;
601 s
->contents
= (bfd_byte
*) bfd_zalloc (output_bfd
, s
->size
);
602 if (s
->contents
== NULL
)
604 bfd_set_error (bfd_error_no_memory
);
612 /* We come here once we are ready to actually write the fixup table to
613 the output file. Scan the fixup tables and so forth and generate
614 the stuff we need. */
617 linux_finish_dynamic_link (output_bfd
, info
)
619 struct bfd_link_info
*info
;
621 asection
*s
, *os
, *is
;
622 bfd_byte
*fixup_table
;
623 struct linux_link_hash_entry
*h
;
625 unsigned int new_addr
;
627 unsigned int fixups_written
;
629 if (linux_hash_table (info
)->dynobj
== NULL
)
632 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
634 BFD_ASSERT (s
!= NULL
);
635 os
= s
->output_section
;
638 #ifdef LINUX_LINK_DEBUG
639 printf ("Fixup table file offset: %x VMA: %x\n",
640 os
->filepos
+ s
->output_offset
,
641 os
->vma
+ s
->output_offset
);
644 fixup_table
= s
->contents
;
645 bfd_put_32 (output_bfd
, (bfd_vma
) linux_hash_table (info
)->fixup_count
,
649 /* Fill in fixup table. */
650 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
655 if (f
->h
->root
.root
.type
!= bfd_link_hash_defined
656 && f
->h
->root
.root
.type
!= bfd_link_hash_defweak
)
658 (*_bfd_error_handler
)
659 (_("Symbol %s not defined for fixups\n"),
660 f
->h
->root
.root
.root
.string
);
664 is
= f
->h
->root
.root
.u
.def
.section
;
665 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
666 new_addr
= f
->h
->root
.root
.u
.def
.value
+ section_offset
;
668 #ifdef LINUX_LINK_DEBUG
669 printf ("Fixup(%d) %s: %x %x\n",f
->jump
, f
->h
->root
.root
.string
,
675 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
677 bfd_put_32 (output_bfd
, f
->value
+ 2, fixup_table
);
682 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
684 bfd_put_32 (output_bfd
, f
->value
, fixup_table
);
690 if (linux_hash_table (info
)->local_builtins
!= 0)
692 /* Special marker so we know to switch to the other type of fixup */
693 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
695 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
698 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
703 if (f
->h
->root
.root
.type
!= bfd_link_hash_defined
704 && f
->h
->root
.root
.type
!= bfd_link_hash_defweak
)
706 (*_bfd_error_handler
)
707 (_("Symbol %s not defined for fixups\n"),
708 f
->h
->root
.root
.root
.string
);
712 is
= f
->h
->root
.root
.u
.def
.section
;
713 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
714 new_addr
= f
->h
->root
.root
.u
.def
.value
+ section_offset
;
716 #ifdef LINUX_LINK_DEBUG
717 printf ("Fixup(B) %s: %x %x\n", f
->h
->root
.root
.string
,
721 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
723 bfd_put_32 (output_bfd
, f
->value
, fixup_table
);
729 if (linux_hash_table (info
)->fixup_count
!= fixups_written
)
731 (*_bfd_error_handler
) (_("Warning: fixup count mismatch\n"));
732 while (linux_hash_table (info
)->fixup_count
> fixups_written
)
734 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
736 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
742 h
= linux_link_hash_lookup (linux_hash_table (info
),
743 "__BUILTIN_FIXUPS__",
744 FALSE
, FALSE
, FALSE
);
747 && (h
->root
.root
.type
== bfd_link_hash_defined
748 || h
->root
.root
.type
== bfd_link_hash_defweak
))
750 is
= h
->root
.root
.u
.def
.section
;
751 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
752 new_addr
= h
->root
.root
.u
.def
.value
+ section_offset
;
754 #ifdef LINUX_LINK_DEBUG
755 printf ("Builtin fixup table at %x\n", new_addr
);
758 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
761 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
763 if (bfd_seek (output_bfd
, (file_ptr
) (os
->filepos
+ s
->output_offset
),
767 if (bfd_bwrite ((PTR
) s
->contents
, s
->size
, output_bfd
) != s
->size
)
773 #define MY_bfd_link_hash_table_create linux_link_hash_table_create
774 #define MY_add_one_symbol linux_add_one_symbol
775 #define MY_finish_dynamic_link linux_finish_dynamic_link
777 #define MY_zmagic_contiguous 1
779 #include "aout-target.h"