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, 2005, 2006, 2007, 2008, 2009, 2011, 2012
4 Free Software Foundation, Inc.
6 This file is part of BFD, the Binary File Descriptor library.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 MA 02110-1301, USA. */
23 #define TARGET_PAGE_SIZE 4096
24 #define ZMAGIC_DISK_BLOCK_SIZE 1024
25 #define SEGMENT_SIZE TARGET_PAGE_SIZE
26 #define TEXT_START_ADDR 0x0
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 (bfd
*, file_ptr
*, file_ptr
*, file_ptr
*);
57 m68klinux_bfd_final_link (bfd
*abfd
,
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 (bfd
*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) (CONST_STRNEQ (name, GOT_REF_PREFIX))
95 /* See if a symbol name is a reference to the procedure linkage table. */
97 #ifndef PLT_REF_PREFIX
98 #define PLT_REF_PREFIX "__PLT_"
101 #define IS_PLT_SYM(name) (CONST_STRNEQ (name, PLT_REF_PREFIX))
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 dynamically
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 /* Routine to create an entry in an Linux link hash table. */
171 static struct bfd_hash_entry
*
172 linux_link_hash_newfunc (struct bfd_hash_entry
*entry
,
173 struct bfd_hash_table
*table
,
176 struct linux_link_hash_entry
*ret
= (struct linux_link_hash_entry
*) entry
;
178 /* Allocate the structure if it has not already been allocated by a
180 if (ret
== (struct linux_link_hash_entry
*) NULL
)
181 ret
= ((struct linux_link_hash_entry
*)
182 bfd_hash_allocate (table
, sizeof (struct linux_link_hash_entry
)));
184 return (struct bfd_hash_entry
*) ret
;
186 /* Call the allocation method of the superclass. */
187 ret
= ((struct linux_link_hash_entry
*)
188 NAME(aout
,link_hash_newfunc
) ((struct bfd_hash_entry
*) ret
,
192 /* Set local fields; there aren't any. */
195 return (struct bfd_hash_entry
*) ret
;
198 /* Create a Linux link hash table. */
200 static struct bfd_link_hash_table
*
201 linux_link_hash_table_create (bfd
*abfd
)
203 struct linux_link_hash_table
*ret
;
204 bfd_size_type amt
= sizeof (struct linux_link_hash_table
);
206 ret
= (struct linux_link_hash_table
*) bfd_malloc (amt
);
207 if (ret
== (struct linux_link_hash_table
*) NULL
)
209 bfd_set_error (bfd_error_no_memory
);
210 return (struct bfd_link_hash_table
*) NULL
;
212 if (!NAME(aout
,link_hash_table_init
) (&ret
->root
, abfd
,
213 linux_link_hash_newfunc
,
214 sizeof (struct linux_link_hash_entry
)))
217 return (struct bfd_link_hash_table
*) NULL
;
221 ret
->fixup_count
= 0;
222 ret
->local_builtins
= 0;
223 ret
->fixup_list
= NULL
;
225 return &ret
->root
.root
;
228 /* Look up an entry in a Linux link hash table. */
230 #define linux_link_hash_lookup(table, string, create, copy, follow) \
231 ((struct linux_link_hash_entry *) \
232 aout_link_hash_lookup (&(table)->root, (string), (create), (copy),\
235 /* Traverse a Linux link hash table. */
237 #define linux_link_hash_traverse(table, func, info) \
238 (aout_link_hash_traverse \
240 (bfd_boolean (*) (struct aout_link_hash_entry *, void *)) (func), \
243 /* Get the Linux link hash table from the info structure. This is
246 #define linux_hash_table(p) ((struct linux_link_hash_table *) ((p)->hash))
248 /* Store the information for a new fixup. */
250 static struct fixup
*
251 new_fixup (struct bfd_link_info
*info
,
252 struct linux_link_hash_entry
*h
,
258 f
= (struct fixup
*) bfd_hash_allocate (&info
->hash
->table
,
259 sizeof (struct fixup
));
262 f
->next
= linux_hash_table (info
)->fixup_list
;
263 linux_hash_table (info
)->fixup_list
= f
;
266 f
->builtin
= builtin
;
268 ++linux_hash_table (info
)->fixup_count
;
272 /* We come here once we realize that we are going to link to a shared
273 library. We need to create a special section that contains the
274 fixup table, and we ultimately need to add a pointer to this into
275 the set vector for SHARABLE_CONFLICTS. At this point we do not
276 know the size of the section, but that's OK - we just need to
277 create it for now. */
280 linux_link_create_dynamic_sections (bfd
*abfd
,
281 struct bfd_link_info
*info ATTRIBUTE_UNUSED
)
286 /* Note that we set the SEC_IN_MEMORY flag. */
287 flags
= SEC_ALLOC
| SEC_LOAD
| SEC_HAS_CONTENTS
| SEC_IN_MEMORY
;
289 /* We choose to use the name ".linux-dynamic" for the fixup table.
291 s
= bfd_make_section_with_flags (abfd
, ".linux-dynamic", flags
);
293 || ! bfd_set_section_alignment (abfd
, s
, 2))
301 /* Function to add a single symbol to the linker hash table. This is
302 a wrapper around _bfd_generic_link_add_one_symbol which handles the
303 tweaking needed for dynamic linking support. */
306 linux_add_one_symbol (struct bfd_link_info
*info
,
315 struct bfd_link_hash_entry
**hashp
)
317 struct linux_link_hash_entry
*h
;
320 /* Look up and see if we already have this symbol in the hash table.
321 If we do, and the defining entry is from a shared library, we
322 need to create the dynamic sections.
324 FIXME: What if abfd->xvec != info->output_bfd->xvec? We may
325 want to be able to link Linux a.out and ELF objects together,
326 but serious confusion is possible. */
330 if (! info
->relocatable
331 && linux_hash_table (info
)->dynobj
== NULL
332 && strcmp (name
, SHARABLE_CONFLICTS
) == 0
333 && (flags
& BSF_CONSTRUCTOR
) != 0
334 && abfd
->xvec
== info
->output_bfd
->xvec
)
336 if (! linux_link_create_dynamic_sections (abfd
, info
))
338 linux_hash_table (info
)->dynobj
= abfd
;
342 if (bfd_is_abs_section (section
)
343 && abfd
->xvec
== info
->output_bfd
->xvec
)
345 h
= linux_link_hash_lookup (linux_hash_table (info
), name
, FALSE
,
348 && (h
->root
.root
.type
== bfd_link_hash_defined
349 || h
->root
.root
.type
== bfd_link_hash_defweak
))
354 *hashp
= (struct bfd_link_hash_entry
*) h
;
356 f
= new_fixup (info
, h
, value
, ! IS_PLT_SYM (name
));
359 f
->jump
= IS_PLT_SYM (name
);
365 /* Do the usual procedure for adding a symbol. */
366 if (! _bfd_generic_link_add_one_symbol (info
, abfd
, name
, flags
, section
,
367 value
, string
, copy
, collect
,
371 /* Insert a pointer to our table in the set vector. The dynamic
372 linker requires this information */
377 /* Here we do our special thing to add the pointer to the
378 dynamic section in the SHARABLE_CONFLICTS set vector. */
379 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
381 BFD_ASSERT (s
!= NULL
);
383 if (! (_bfd_generic_link_add_one_symbol
384 (info
, linux_hash_table (info
)->dynobj
, SHARABLE_CONFLICTS
,
385 BSF_GLOBAL
| BSF_CONSTRUCTOR
, s
, (bfd_vma
) 0, NULL
,
386 FALSE
, FALSE
, NULL
)))
393 /* We will crawl the hash table and come here for every global symbol.
394 We will examine each entry and see if there are indications that we
395 need to add a fixup. There are two possible cases - one is where
396 you have duplicate definitions of PLT or GOT symbols - these will
397 have already been caught and added as "builtin" fixups. If we find
398 that the corresponding non PLT/GOT symbol is also present, we
399 convert it to a regular fixup instead.
401 This function is called via linux_link_hash_traverse. */
404 linux_tally_symbols (struct linux_link_hash_entry
*h
,
407 struct bfd_link_info
*info
= (struct bfd_link_info
*) data
;
408 struct fixup
*f
, *f1
;
410 struct linux_link_hash_entry
*h1
, *h2
;
413 if (h
->root
.root
.type
== bfd_link_hash_undefined
414 && CONST_STRNEQ (h
->root
.root
.root
.string
, NEEDS_SHRLIB
))
420 name
= h
->root
.root
.root
.string
+ sizeof NEEDS_SHRLIB
- 1;
421 p
= strrchr (name
, '_');
423 alloc
= (char *) bfd_malloc ((bfd_size_type
) strlen (name
) + 1);
425 if (p
== NULL
|| alloc
== NULL
)
426 (*_bfd_error_handler
) (_("Output file requires shared library `%s'\n"),
430 strcpy (alloc
, name
);
431 p
= strrchr (alloc
, '_');
433 (*_bfd_error_handler
)
434 (_("Output file requires shared library `%s.so.%s'\n"),
442 /* If this symbol is not a PLT/GOT, we do not even need to look at it */
443 is_plt
= IS_PLT_SYM (h
->root
.root
.root
.string
);
445 if (is_plt
|| IS_GOT_SYM (h
->root
.root
.root
.string
))
447 /* Look up this symbol twice. Once just as a regular lookup,
448 and then again following all of the indirect links until we
449 reach a real symbol. */
450 h1
= linux_link_hash_lookup (linux_hash_table (info
),
451 (h
->root
.root
.root
.string
452 + sizeof PLT_REF_PREFIX
- 1),
454 /* h2 does not follow indirect symbols. */
455 h2
= linux_link_hash_lookup (linux_hash_table (info
),
456 (h
->root
.root
.root
.string
457 + sizeof PLT_REF_PREFIX
- 1),
458 FALSE
, FALSE
, FALSE
);
460 /* The real symbol must exist but if it is also an ABS symbol,
461 there is no need to have a fixup. This is because they both
462 came from the same library. If on the other hand, we had to
463 use an indirect symbol to get to the real symbol, we add the
464 fixup anyway, since there are cases where these symbols come
465 from different shared libraries */
467 && (((h1
->root
.root
.type
== bfd_link_hash_defined
468 || h1
->root
.root
.type
== bfd_link_hash_defweak
)
469 && ! bfd_is_abs_section (h1
->root
.root
.u
.def
.section
))
470 || h2
->root
.root
.type
== bfd_link_hash_indirect
))
472 /* See if there is a "builtin" fixup already present
473 involving this symbol. If so, convert it to a regular
474 fixup. In the end, this relaxes some of the requirements
475 about the order of performing fixups. */
477 for (f1
= linux_hash_table (info
)->fixup_list
;
481 if ((f1
->h
!= h
&& f1
->h
!= h1
)
482 || (! f1
->builtin
&& ! f1
->jump
))
487 && bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
489 f
= new_fixup (info
, h1
, f1
->h
->root
.root
.u
.def
.value
, 0);
498 && bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
500 f
= new_fixup (info
, h1
, h
->root
.root
.u
.def
.value
, 0);
503 /* FIXME: No way to return error. */
510 /* Quick and dirty way of stripping these symbols from the
512 if (bfd_is_abs_section (h
->root
.root
.u
.def
.section
))
513 h
->root
.written
= TRUE
;
519 /* This is called to set the size of the .linux-dynamic section is.
520 It is called by the Linux linker emulation before_allocation
521 routine. We have finished reading all of the input files, and now
522 we just scan the hash tables to find out how many additional fixups
526 bfd_m68klinux_size_dynamic_sections (bfd
*output_bfd
,
527 struct bfd_link_info
*info
)
532 if (output_bfd
->xvec
!= &MY(vec
))
535 /* First find the fixups... */
536 linux_link_hash_traverse (linux_hash_table (info
),
540 /* If there are builtin fixups, leave room for a marker. This is
541 used by the dynamic linker so that it knows that all that follow
542 are builtin fixups instead of regular fixups. */
543 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
547 ++linux_hash_table (info
)->fixup_count
;
548 ++linux_hash_table (info
)->local_builtins
;
553 if (linux_hash_table (info
)->dynobj
== NULL
)
555 if (linux_hash_table (info
)->fixup_count
> 0)
560 /* Allocate memory for our fixup table. We will fill it in later. */
561 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
565 s
->size
= linux_hash_table (info
)->fixup_count
+ 1;
567 s
->contents
= (bfd_byte
*) bfd_zalloc (output_bfd
, s
->size
);
568 if (s
->contents
== NULL
)
570 bfd_set_error (bfd_error_no_memory
);
578 /* We come here once we are ready to actually write the fixup table to
579 the output file. Scan the fixup tables and so forth and generate
580 the stuff we need. */
583 linux_finish_dynamic_link (bfd
*output_bfd
, struct bfd_link_info
*info
)
585 asection
*s
, *os
, *is
;
586 bfd_byte
*fixup_table
;
587 struct linux_link_hash_entry
*h
;
589 unsigned int new_addr
;
591 unsigned int fixups_written
;
593 if (linux_hash_table (info
)->dynobj
== NULL
)
596 s
= bfd_get_section_by_name (linux_hash_table (info
)->dynobj
,
598 BFD_ASSERT (s
!= NULL
);
599 os
= s
->output_section
;
602 #ifdef LINUX_LINK_DEBUG
603 printf ("Fixup table file offset: %x VMA: %x\n",
604 os
->filepos
+ s
->output_offset
,
605 os
->vma
+ s
->output_offset
);
608 fixup_table
= s
->contents
;
609 bfd_put_32 (output_bfd
, (bfd_vma
) linux_hash_table (info
)->fixup_count
,
613 /* Fill in fixup table. */
614 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
619 if (f
->h
->root
.root
.type
!= bfd_link_hash_defined
620 && f
->h
->root
.root
.type
!= bfd_link_hash_defweak
)
622 (*_bfd_error_handler
)
623 (_("Symbol %s not defined for fixups\n"),
624 f
->h
->root
.root
.root
.string
);
628 is
= f
->h
->root
.root
.u
.def
.section
;
629 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
630 new_addr
= f
->h
->root
.root
.u
.def
.value
+ section_offset
;
632 #ifdef LINUX_LINK_DEBUG
633 printf ("Fixup(%d) %s: %x %x\n",f
->jump
, f
->h
->root
.root
.string
,
639 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
641 bfd_put_32 (output_bfd
, f
->value
+ 2, fixup_table
);
646 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
648 bfd_put_32 (output_bfd
, f
->value
, fixup_table
);
654 if (linux_hash_table (info
)->local_builtins
!= 0)
656 /* Special marker so we know to switch to the other type of fixup */
657 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
659 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
662 for (f
= linux_hash_table (info
)->fixup_list
; f
!= NULL
; f
= f
->next
)
667 if (f
->h
->root
.root
.type
!= bfd_link_hash_defined
668 && f
->h
->root
.root
.type
!= bfd_link_hash_defweak
)
670 (*_bfd_error_handler
)
671 (_("Symbol %s not defined for fixups\n"),
672 f
->h
->root
.root
.root
.string
);
676 is
= f
->h
->root
.root
.u
.def
.section
;
677 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
678 new_addr
= f
->h
->root
.root
.u
.def
.value
+ section_offset
;
680 #ifdef LINUX_LINK_DEBUG
681 printf ("Fixup(B) %s: %x %x\n", f
->h
->root
.root
.string
,
685 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
687 bfd_put_32 (output_bfd
, f
->value
, fixup_table
);
693 if (linux_hash_table (info
)->fixup_count
!= fixups_written
)
695 (*_bfd_error_handler
) (_("Warning: fixup count mismatch\n"));
696 while (linux_hash_table (info
)->fixup_count
> fixups_written
)
698 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
700 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
706 h
= linux_link_hash_lookup (linux_hash_table (info
),
707 "__BUILTIN_FIXUPS__",
708 FALSE
, FALSE
, FALSE
);
711 && (h
->root
.root
.type
== bfd_link_hash_defined
712 || h
->root
.root
.type
== bfd_link_hash_defweak
))
714 is
= h
->root
.root
.u
.def
.section
;
715 section_offset
= is
->output_section
->vma
+ is
->output_offset
;
716 new_addr
= h
->root
.root
.u
.def
.value
+ section_offset
;
718 #ifdef LINUX_LINK_DEBUG
719 printf ("Builtin fixup table at %x\n", new_addr
);
722 bfd_put_32 (output_bfd
, (bfd_vma
) new_addr
, fixup_table
);
725 bfd_put_32 (output_bfd
, (bfd_vma
) 0, fixup_table
);
727 if (bfd_seek (output_bfd
, (file_ptr
) (os
->filepos
+ s
->output_offset
),
731 if (bfd_bwrite (s
->contents
, s
->size
, output_bfd
) != s
->size
)
737 #define MY_bfd_link_hash_table_create linux_link_hash_table_create
738 #define MY_add_one_symbol linux_add_one_symbol
739 #define MY_finish_dynamic_link linux_finish_dynamic_link
741 #define MY_zmagic_contiguous 1
743 #include "aout-target.h"