1
/* BFD back-end for linux flavored m68k a.out binaries.
2
Copyright 1992, 1993, 1994, 1995, 1996, 1997, 1999, 2000, 2001, 2002
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_malloc (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_warning)
446
h = (struct linux_link_hash_entry *) h->root.root.u.i.link;
448
if (h->root.root.type == bfd_link_hash_undefined
449
&& strncmp (h->root.root.root.string, NEEDS_SHRLIB,
450
sizeof NEEDS_SHRLIB - 1) == 0)
456
name = h->root.root.root.string + sizeof NEEDS_SHRLIB - 1;
457
p = strrchr (name, '_');
459
alloc = (char *) bfd_malloc ((bfd_size_type) strlen (name) + 1);
461
if (p == NULL || alloc == NULL)
462
(*_bfd_error_handler) (_("Output file requires shared library `%s'\n"),
466
strcpy (alloc, name);
467
p = strrchr (alloc, '_');
469
(*_bfd_error_handler)
470
(_("Output file requires shared library `%s.so.%s'\n"),
478
/* If this symbol is not a PLT/GOT, we do not even need to look at it */
479
is_plt = IS_PLT_SYM (h->root.root.root.string);
481
if (is_plt || IS_GOT_SYM (h->root.root.root.string))
483
/* Look up this symbol twice. Once just as a regular lookup,
484
and then again following all of the indirect links until we
485
reach a real symbol. */
486
h1 = linux_link_hash_lookup (linux_hash_table (info),
487
(h->root.root.root.string
488
+ sizeof PLT_REF_PREFIX - 1),
490
/* h2 does not follow indirect symbols. */
491
h2 = linux_link_hash_lookup (linux_hash_table (info),
492
(h->root.root.root.string
493
+ sizeof PLT_REF_PREFIX - 1),
494
false, false, false);
496
/* The real symbol must exist but if it is also an ABS symbol,
497
there is no need to have a fixup. This is because they both
498
came from the same library. If on the other hand, we had to
499
use an indirect symbol to get to the real symbol, we add the
500
fixup anyway, since there are cases where these symbols come
501
from different shared libraries */
503
&& (((h1->root.root.type == bfd_link_hash_defined
504
|| h1->root.root.type == bfd_link_hash_defweak)
505
&& ! bfd_is_abs_section (h1->root.root.u.def.section))
506
|| h2->root.root.type == bfd_link_hash_indirect))
508
/* See if there is a "builtin" fixup already present
509
involving this symbol. If so, convert it to a regular
510
fixup. In the end, this relaxes some of the requirements
511
about the order of performing fixups. */
513
for (f1 = linux_hash_table (info)->fixup_list;
517
if ((f1->h != h && f1->h != h1)
518
|| (! f1->builtin && ! f1->jump))
523
&& bfd_is_abs_section (h->root.root.u.def.section))
525
f = new_fixup (info, h1, f1->h->root.root.u.def.value, 0);
534
&& bfd_is_abs_section (h->root.root.u.def.section))
536
f = new_fixup (info, h1, h->root.root.u.def.value, 0);
539
/* FIXME: No way to return error. */
546
/* Quick and dirty way of stripping these symbols from the
548
if (bfd_is_abs_section (h->root.root.u.def.section))
549
h->root.written = true;
555
/* This is called to set the size of the .linux-dynamic section is.
556
It is called by the Linux linker emulation before_allocation
557
routine. We have finished reading all of the input files, and now
558
we just scan the hash tables to find out how many additional fixups
562
bfd_m68klinux_size_dynamic_sections (output_bfd, info)
564
struct bfd_link_info *info;
569
if (output_bfd->xvec != &MY(vec))
572
/* First find the fixups... */
573
linux_link_hash_traverse (linux_hash_table (info),
577
/* If there are builtin fixups, leave room for a marker. This is
578
used by the dynamic linker so that it knows that all that follow
579
are builtin fixups instead of regular fixups. */
580
for (f = linux_hash_table (info)->fixup_list; f != NULL; f = f->next)
584
++linux_hash_table (info)->fixup_count;
585
++linux_hash_table (info)->local_builtins;
590
if (linux_hash_table (info)->dynobj == NULL)
592
if (linux_hash_table (info)->fixup_count > 0)
597
/* Allocate memory for our fixup table. We will fill it in later. */
598
s = bfd_get_section_by_name (linux_hash_table (info)->dynobj,
602
s->_raw_size = linux_hash_table (info)->fixup_count + 1;
604
s->contents = (bfd_byte *) bfd_zalloc (output_bfd, s->_raw_size);
605
if (s->contents == NULL)
607
bfd_set_error (bfd_error_no_memory);
615
/* We come here once we are ready to actually write the fixup table to
616
the output file. Scan the fixup tables and so forth and generate
617
the stuff we need. */
620
linux_finish_dynamic_link (output_bfd, info)
622
struct bfd_link_info *info;
624
asection *s, *os, *is;
625
bfd_byte *fixup_table;
626
struct linux_link_hash_entry *h;
628
unsigned int new_addr;
630
unsigned int fixups_written;
632
if (linux_hash_table (info)->dynobj == NULL)
635
s = bfd_get_section_by_name (linux_hash_table (info)->dynobj,
637
BFD_ASSERT (s != NULL);
638
os = s->output_section;
641
#ifdef LINUX_LINK_DEBUG
642
printf ("Fixup table file offset: %x VMA: %x\n",
643
os->filepos + s->output_offset,
644
os->vma + s->output_offset);
647
fixup_table = s->contents;
648
bfd_put_32 (output_bfd, (bfd_vma) linux_hash_table (info)->fixup_count,
652
/* Fill in fixup table. */
653
for (f = linux_hash_table (info)->fixup_list; f != NULL; f = f->next)
658
if (f->h->root.root.type != bfd_link_hash_defined
659
&& f->h->root.root.type != bfd_link_hash_defweak)
661
(*_bfd_error_handler)
662
(_("Symbol %s not defined for fixups\n"),
663
f->h->root.root.root.string);
667
is = f->h->root.root.u.def.section;
668
section_offset = is->output_section->vma + is->output_offset;
669
new_addr = f->h->root.root.u.def.value + section_offset;
671
#ifdef LINUX_LINK_DEBUG
672
printf ("Fixup(%d) %s: %x %x\n",f->jump, f->h->root.root.string,
678
bfd_put_32 (output_bfd, (bfd_vma) new_addr, fixup_table);
680
bfd_put_32 (output_bfd, f->value + 2, fixup_table);
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)->local_builtins != 0)
695
/* Special marker so we know to switch to the other type of fixup */
696
bfd_put_32 (output_bfd, (bfd_vma) 0, fixup_table);
698
bfd_put_32 (output_bfd, (bfd_vma) 0, fixup_table);
701
for (f = linux_hash_table (info)->fixup_list; f != NULL; f = f->next)
706
if (f->h->root.root.type != bfd_link_hash_defined
707
&& f->h->root.root.type != bfd_link_hash_defweak)
709
(*_bfd_error_handler)
710
(_("Symbol %s not defined for fixups\n"),
711
f->h->root.root.root.string);
715
is = f->h->root.root.u.def.section;
716
section_offset = is->output_section->vma + is->output_offset;
717
new_addr = f->h->root.root.u.def.value + section_offset;
719
#ifdef LINUX_LINK_DEBUG
720
printf ("Fixup(B) %s: %x %x\n", f->h->root.root.string,
724
bfd_put_32 (output_bfd, (bfd_vma) new_addr, fixup_table);
726
bfd_put_32 (output_bfd, f->value, fixup_table);
732
if (linux_hash_table (info)->fixup_count != fixups_written)
734
(*_bfd_error_handler) (_("Warning: fixup count mismatch\n"));
735
while (linux_hash_table (info)->fixup_count > fixups_written)
737
bfd_put_32 (output_bfd, (bfd_vma) 0, fixup_table);
739
bfd_put_32 (output_bfd, (bfd_vma) 0, fixup_table);
745
h = linux_link_hash_lookup (linux_hash_table (info),
746
"__BUILTIN_FIXUPS__",
747
false, false, false);
750
&& (h->root.root.type == bfd_link_hash_defined
751
|| h->root.root.type == bfd_link_hash_defweak))
753
is = h->root.root.u.def.section;
754
section_offset = is->output_section->vma + is->output_offset;
755
new_addr = h->root.root.u.def.value + section_offset;
757
#ifdef LINUX_LINK_DEBUG
758
printf ("Builtin fixup table at %x\n", new_addr);
761
bfd_put_32 (output_bfd, (bfd_vma) new_addr, fixup_table);
764
bfd_put_32 (output_bfd, (bfd_vma) 0, fixup_table);
766
if (bfd_seek (output_bfd, (file_ptr) (os->filepos + s->output_offset),
770
if (bfd_bwrite ((PTR) s->contents, s->_raw_size, output_bfd) != s->_raw_size)
776
#define MY_bfd_link_hash_table_create linux_link_hash_table_create
777
#define MY_add_one_symbol linux_add_one_symbol
778
#define MY_finish_dynamic_link linux_finish_dynamic_link
780
#define MY_zmagic_contiguous 1
782
#include "aout-target.h"