1 /* X86-64 specific support for 64-bit ELF
2    Copyright 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
3    Contributed by Jan Hubicka <jh@suse.cz>.
4 
5    This file is part of BFD, the Binary File Descriptor library.
6 
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.
11 
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.
16 
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.  */
20 
21 #include "bfd.h"
22 #include "sysdep.h"
23 #include "bfdlink.h"
24 #include "libbfd.h"
25 #include "elf-bfd.h"
26 
27 #include "elf/x86-64.h"
28 
29 /* In case we're on a 32-bit machine, construct a 64-bit "-1" value.  */
30 #define MINUS_ONE (~ (bfd_vma) 0)
31 
32 /* The relocation "howto" table.  Order of fields:
33    type, size, bitsize, pc_relative, complain_on_overflow,
34    special_function, name, partial_inplace, src_mask, dst_pack, pcrel_offset.  */
35 static reloc_howto_type x86_64_elf_howto_table[] =
36 {
37   HOWTO(R_X86_64_NONE, 0, 0, 0, FALSE, 0, complain_overflow_dont,
38 	bfd_elf_generic_reloc, "R_X86_64_NONE",	FALSE, 0x00000000, 0x00000000,
39 	FALSE),
40   HOWTO(R_X86_64_64, 0, 4, 64, FALSE, 0, complain_overflow_bitfield,
41 	bfd_elf_generic_reloc, "R_X86_64_64", FALSE, MINUS_ONE, MINUS_ONE,
42 	FALSE),
43   HOWTO(R_X86_64_PC32, 0, 2, 32, TRUE, 0, complain_overflow_signed,
44 	bfd_elf_generic_reloc, "R_X86_64_PC32", FALSE, 0xffffffff, 0xffffffff,
45 	TRUE),
46   HOWTO(R_X86_64_GOT32, 0, 2, 32, FALSE, 0, complain_overflow_signed,
47 	bfd_elf_generic_reloc, "R_X86_64_GOT32", FALSE, 0xffffffff, 0xffffffff,
48 	FALSE),
49   HOWTO(R_X86_64_PLT32, 0, 2, 32, TRUE, 0, complain_overflow_signed,
50 	bfd_elf_generic_reloc, "R_X86_64_PLT32", FALSE, 0xffffffff, 0xffffffff,
51 	TRUE),
52   HOWTO(R_X86_64_COPY, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
53 	bfd_elf_generic_reloc, "R_X86_64_COPY", FALSE, 0xffffffff, 0xffffffff,
54 	FALSE),
55   HOWTO(R_X86_64_GLOB_DAT, 0, 4, 64, FALSE, 0, complain_overflow_bitfield,
56 	bfd_elf_generic_reloc, "R_X86_64_GLOB_DAT", FALSE, MINUS_ONE,
57 	MINUS_ONE, FALSE),
58   HOWTO(R_X86_64_JUMP_SLOT, 0, 4, 64, FALSE, 0, complain_overflow_bitfield,
59 	bfd_elf_generic_reloc, "R_X86_64_JUMP_SLOT", FALSE, MINUS_ONE,
60 	MINUS_ONE, FALSE),
61   HOWTO(R_X86_64_RELATIVE, 0, 4, 64, FALSE, 0, complain_overflow_bitfield,
62 	bfd_elf_generic_reloc, "R_X86_64_RELATIVE", FALSE, MINUS_ONE,
63 	MINUS_ONE, FALSE),
64   HOWTO(R_X86_64_GOTPCREL, 0, 2, 32, TRUE, 0, complain_overflow_signed,
65 	bfd_elf_generic_reloc, "R_X86_64_GOTPCREL", FALSE, 0xffffffff,
66 	0xffffffff, TRUE),
67   HOWTO(R_X86_64_32, 0, 2, 32, FALSE, 0, complain_overflow_unsigned,
68 	bfd_elf_generic_reloc, "R_X86_64_32", FALSE, 0xffffffff, 0xffffffff,
69 	FALSE),
70   HOWTO(R_X86_64_32S, 0, 2, 32, FALSE, 0, complain_overflow_signed,
71 	bfd_elf_generic_reloc, "R_X86_64_32S", FALSE, 0xffffffff, 0xffffffff,
72 	FALSE),
73   HOWTO(R_X86_64_16, 0, 1, 16, FALSE, 0, complain_overflow_bitfield,
74 	bfd_elf_generic_reloc, "R_X86_64_16", FALSE, 0xffff, 0xffff, FALSE),
75   HOWTO(R_X86_64_PC16,0, 1, 16, TRUE, 0, complain_overflow_bitfield,
76 	bfd_elf_generic_reloc, "R_X86_64_PC16", FALSE, 0xffff, 0xffff, TRUE),
77   HOWTO(R_X86_64_8, 0, 0, 8, FALSE, 0, complain_overflow_signed,
78 	bfd_elf_generic_reloc, "R_X86_64_8", FALSE, 0xff, 0xff, FALSE),
79   HOWTO(R_X86_64_PC8, 0, 0, 8, TRUE, 0, complain_overflow_signed,
80 	bfd_elf_generic_reloc, "R_X86_64_PC8", FALSE, 0xff, 0xff, TRUE),
81   HOWTO(R_X86_64_DTPMOD64, 0, 4, 64, FALSE, 0, complain_overflow_bitfield,
82 	bfd_elf_generic_reloc, "R_X86_64_DTPMOD64", FALSE, MINUS_ONE,
83 	MINUS_ONE, FALSE),
84   HOWTO(R_X86_64_DTPOFF64, 0, 4, 64, FALSE, 0, complain_overflow_bitfield,
85 	bfd_elf_generic_reloc, "R_X86_64_DTPOFF64", FALSE, MINUS_ONE,
86 	MINUS_ONE, FALSE),
87   HOWTO(R_X86_64_TPOFF64, 0, 4, 64, FALSE, 0, complain_overflow_bitfield,
88 	bfd_elf_generic_reloc, "R_X86_64_TPOFF64", FALSE, MINUS_ONE,
89 	MINUS_ONE, FALSE),
90   HOWTO(R_X86_64_TLSGD, 0, 2, 32, TRUE, 0, complain_overflow_signed,
91 	bfd_elf_generic_reloc, "R_X86_64_TLSGD", FALSE, 0xffffffff,
92 	0xffffffff, TRUE),
93   HOWTO(R_X86_64_TLSLD, 0, 2, 32, TRUE, 0, complain_overflow_signed,
94 	bfd_elf_generic_reloc, "R_X86_64_TLSLD", FALSE, 0xffffffff,
95 	0xffffffff, TRUE),
96   HOWTO(R_X86_64_DTPOFF32, 0, 2, 32, FALSE, 0, complain_overflow_bitfield,
97 	bfd_elf_generic_reloc, "R_X86_64_DTPOFF32", FALSE, 0xffffffff,
98 	0xffffffff, FALSE),
99   HOWTO(R_X86_64_GOTTPOFF, 0, 2, 32, TRUE, 0, complain_overflow_signed,
100 	bfd_elf_generic_reloc, "R_X86_64_GOTTPOFF", FALSE, 0xffffffff,
101 	0xffffffff, TRUE),
102   HOWTO(R_X86_64_TPOFF32, 0, 2, 32, FALSE, 0, complain_overflow_signed,
103 	bfd_elf_generic_reloc, "R_X86_64_TPOFF32", FALSE, 0xffffffff,
104 	0xffffffff, FALSE),
105 
106 /* GNU extension to record C++ vtable hierarchy.  */
107   HOWTO (R_X86_64_GNU_VTINHERIT, 0, 4, 0, FALSE, 0, complain_overflow_dont,
108 	 NULL, "R_X86_64_GNU_VTINHERIT", FALSE, 0, 0, FALSE),
109 
110 /* GNU extension to record C++ vtable member usage.  */
111   HOWTO (R_X86_64_GNU_VTENTRY, 0, 4, 0, FALSE, 0, complain_overflow_dont,
112 	 _bfd_elf_rel_vtable_reloc_fn, "R_X86_64_GNU_VTENTRY", FALSE, 0, 0,
113 	 FALSE)
114 };
115 
116 /* Map BFD relocs to the x86_64 elf relocs.  */
117 struct elf_reloc_map
118 {
119   bfd_reloc_code_real_type bfd_reloc_val;
120   unsigned char elf_reloc_val;
121 };
122 
123 static const struct elf_reloc_map x86_64_reloc_map[] =
124 {
125   { BFD_RELOC_NONE,		R_X86_64_NONE, },
126   { BFD_RELOC_64,		R_X86_64_64,   },
127   { BFD_RELOC_32_PCREL,		R_X86_64_PC32, },
128   { BFD_RELOC_X86_64_GOT32,	R_X86_64_GOT32,},
129   { BFD_RELOC_X86_64_PLT32,	R_X86_64_PLT32,},
130   { BFD_RELOC_X86_64_COPY,	R_X86_64_COPY, },
131   { BFD_RELOC_X86_64_GLOB_DAT,	R_X86_64_GLOB_DAT, },
132   { BFD_RELOC_X86_64_JUMP_SLOT, R_X86_64_JUMP_SLOT, },
133   { BFD_RELOC_X86_64_RELATIVE,	R_X86_64_RELATIVE, },
134   { BFD_RELOC_X86_64_GOTPCREL,	R_X86_64_GOTPCREL, },
135   { BFD_RELOC_32,		R_X86_64_32, },
136   { BFD_RELOC_X86_64_32S,	R_X86_64_32S, },
137   { BFD_RELOC_16,		R_X86_64_16, },
138   { BFD_RELOC_16_PCREL,		R_X86_64_PC16, },
139   { BFD_RELOC_8,		R_X86_64_8, },
140   { BFD_RELOC_8_PCREL,		R_X86_64_PC8, },
141   { BFD_RELOC_X86_64_DTPMOD64,	R_X86_64_DTPMOD64, },
142   { BFD_RELOC_X86_64_DTPOFF64,	R_X86_64_DTPOFF64, },
143   { BFD_RELOC_X86_64_TPOFF64,	R_X86_64_TPOFF64, },
144   { BFD_RELOC_X86_64_TLSGD,	R_X86_64_TLSGD, },
145   { BFD_RELOC_X86_64_TLSLD,	R_X86_64_TLSLD, },
146   { BFD_RELOC_X86_64_DTPOFF32,	R_X86_64_DTPOFF32, },
147   { BFD_RELOC_X86_64_GOTTPOFF,	R_X86_64_GOTTPOFF, },
148   { BFD_RELOC_X86_64_TPOFF32,	R_X86_64_TPOFF32, },
149   { BFD_RELOC_VTABLE_INHERIT,	R_X86_64_GNU_VTINHERIT, },
150   { BFD_RELOC_VTABLE_ENTRY,	R_X86_64_GNU_VTENTRY, },
151 };
152 
153 
154 /* Given a BFD reloc type, return a HOWTO structure.  */
155 static reloc_howto_type *
elf64_x86_64_reloc_type_lookup(bfd * abfd ATTRIBUTE_UNUSED,bfd_reloc_code_real_type code)156 elf64_x86_64_reloc_type_lookup (bfd *abfd ATTRIBUTE_UNUSED,
157 				bfd_reloc_code_real_type code)
158 {
159   unsigned int i;
160 
161   for (i = 0; i < sizeof (x86_64_reloc_map) / sizeof (struct elf_reloc_map);
162        i++)
163     {
164       if (x86_64_reloc_map[i].bfd_reloc_val == code)
165 	return &x86_64_elf_howto_table[i];
166     }
167   return 0;
168 }
169 
170 /* Given an x86_64 ELF reloc type, fill in an arelent structure.  */
171 
172 static void
elf64_x86_64_info_to_howto(bfd * abfd ATTRIBUTE_UNUSED,arelent * cache_ptr,Elf_Internal_Rela * dst)173 elf64_x86_64_info_to_howto (bfd *abfd ATTRIBUTE_UNUSED, arelent *cache_ptr,
174 			    Elf_Internal_Rela *dst)
175 {
176   unsigned r_type, i;
177 
178   r_type = ELF64_R_TYPE (dst->r_info);
179   if (r_type < (unsigned int) R_X86_64_GNU_VTINHERIT)
180     {
181       BFD_ASSERT (r_type <= (unsigned int) R_X86_64_TPOFF32);
182       i = r_type;
183     }
184   else
185     {
186       BFD_ASSERT (r_type < (unsigned int) R_X86_64_max);
187       i = r_type - ((unsigned int) R_X86_64_GNU_VTINHERIT - R_X86_64_TPOFF32 - 1);
188     }
189   cache_ptr->howto = &x86_64_elf_howto_table[i];
190   BFD_ASSERT (r_type == cache_ptr->howto->type);
191 }
192 
193 /* Support for core dump NOTE sections.  */
194 static bfd_boolean
elf64_x86_64_grok_prstatus(bfd * abfd,Elf_Internal_Note * note)195 elf64_x86_64_grok_prstatus (bfd *abfd, Elf_Internal_Note *note)
196 {
197   int offset;
198   size_t raw_size;
199 
200   switch (note->descsz)
201     {
202       default:
203 	return FALSE;
204 
205       case 336:		/* sizeof(istruct elf_prstatus) on Linux/x86_64 */
206 	/* pr_cursig */
207 	elf_tdata (abfd)->core_signal
208 	  = bfd_get_16 (abfd, note->descdata + 12);
209 
210 	/* pr_pid */
211 	elf_tdata (abfd)->core_pid
212 	  = bfd_get_32 (abfd, note->descdata + 32);
213 
214 	/* pr_reg */
215 	offset = 112;
216 	raw_size = 216;
217 
218 	break;
219     }
220 
221   /* Make a ".reg/999" section.  */
222   return _bfd_elfcore_make_pseudosection (abfd, ".reg",
223 					  raw_size, note->descpos + offset);
224 }
225 
226 static bfd_boolean
elf64_x86_64_grok_psinfo(bfd * abfd,Elf_Internal_Note * note)227 elf64_x86_64_grok_psinfo (bfd *abfd, Elf_Internal_Note *note)
228 {
229   switch (note->descsz)
230     {
231       default:
232 	return FALSE;
233 
234       case 136:		/* sizeof(struct elf_prpsinfo) on Linux/x86_64 */
235 	elf_tdata (abfd)->core_program
236 	 = _bfd_elfcore_strndup (abfd, note->descdata + 40, 16);
237 	elf_tdata (abfd)->core_command
238 	 = _bfd_elfcore_strndup (abfd, note->descdata + 56, 80);
239     }
240 
241   /* Note that for some reason, a spurious space is tacked
242      onto the end of the args in some (at least one anyway)
243      implementations, so strip it off if it exists.  */
244 
245   {
246     char *command = elf_tdata (abfd)->core_command;
247     int n = strlen (command);
248 
249     if (0 < n && command[n - 1] == ' ')
250       command[n - 1] = '\0';
251   }
252 
253   return TRUE;
254 }
255 
256 /* Functions for the x86-64 ELF linker.	 */
257 
258 /* The name of the dynamic interpreter.	 This is put in the .interp
259    section.  */
260 
261 #define ELF_DYNAMIC_INTERPRETER "/lib/ld64.so.1"
262 
263 /* If ELIMINATE_COPY_RELOCS is non-zero, the linker will try to avoid
264    copying dynamic variables from a shared lib into an app's dynbss
265    section, and instead use a dynamic relocation to point into the
266    shared lib.  */
267 #define ELIMINATE_COPY_RELOCS 1
268 
269 /* The size in bytes of an entry in the global offset table.  */
270 
271 #define GOT_ENTRY_SIZE 8
272 
273 /* The size in bytes of an entry in the procedure linkage table.  */
274 
275 #define PLT_ENTRY_SIZE 16
276 
277 /* The first entry in a procedure linkage table looks like this.  See the
278    SVR4 ABI i386 supplement and the x86-64 ABI to see how this works.  */
279 
280 static const bfd_byte elf64_x86_64_plt0_entry[PLT_ENTRY_SIZE] =
281 {
282   0xff, 0x35, 8, 0, 0, 0,	/* pushq GOT+8(%rip)  */
283   0xff, 0x25, 16, 0, 0, 0,	/* jmpq *GOT+16(%rip) */
284   0x90, 0x90, 0x90, 0x90	/* pad out to 16 bytes with nops.  */
285 };
286 
287 /* Subsequent entries in a procedure linkage table look like this.  */
288 
289 static const bfd_byte elf64_x86_64_plt_entry[PLT_ENTRY_SIZE] =
290 {
291   0xff, 0x25,	/* jmpq *name@GOTPC(%rip) */
292   0, 0, 0, 0,	/* replaced with offset to this symbol in .got.	 */
293   0x68,		/* pushq immediate */
294   0, 0, 0, 0,	/* replaced with index into relocation table.  */
295   0xe9,		/* jmp relative */
296   0, 0, 0, 0	/* replaced with offset to start of .plt0.  */
297 };
298 
299 /* The x86-64 linker needs to keep track of the number of relocs that
300    it decides to copy as dynamic relocs in check_relocs for each symbol.
301    This is so that it can later discard them if they are found to be
302    unnecessary.  We store the information in a field extending the
303    regular ELF linker hash table.  */
304 
305 struct elf64_x86_64_dyn_relocs
306 {
307   /* Next section.  */
308   struct elf64_x86_64_dyn_relocs *next;
309 
310   /* The input section of the reloc.  */
311   asection *sec;
312 
313   /* Total number of relocs copied for the input section.  */
314   bfd_size_type count;
315 
316   /* Number of pc-relative relocs copied for the input section.  */
317   bfd_size_type pc_count;
318 };
319 
320 /* x86-64 ELF linker hash entry.  */
321 
322 struct elf64_x86_64_link_hash_entry
323 {
324   struct elf_link_hash_entry elf;
325 
326   /* Track dynamic relocs copied for this symbol.  */
327   struct elf64_x86_64_dyn_relocs *dyn_relocs;
328 
329 #define GOT_UNKNOWN	0
330 #define GOT_NORMAL	1
331 #define GOT_TLS_GD	2
332 #define GOT_TLS_IE	3
333   unsigned char tls_type;
334 };
335 
336 #define elf64_x86_64_hash_entry(ent) \
337   ((struct elf64_x86_64_link_hash_entry *)(ent))
338 
339 struct elf64_x86_64_obj_tdata
340 {
341   struct elf_obj_tdata root;
342 
343   /* tls_type for each local got entry.  */
344   char *local_got_tls_type;
345 };
346 
347 #define elf64_x86_64_tdata(abfd) \
348   ((struct elf64_x86_64_obj_tdata *) (abfd)->tdata.any)
349 
350 #define elf64_x86_64_local_got_tls_type(abfd) \
351   (elf64_x86_64_tdata (abfd)->local_got_tls_type)
352 
353 
354 /* x86-64 ELF linker hash table.  */
355 
356 struct elf64_x86_64_link_hash_table
357 {
358   struct elf_link_hash_table elf;
359 
360   /* Short-cuts to get to dynamic linker sections.  */
361   asection *sgot;
362   asection *sgotplt;
363   asection *srelgot;
364   asection *splt;
365   asection *srelplt;
366   asection *sdynbss;
367   asection *srelbss;
368 
369   union {
370     bfd_signed_vma refcount;
371     bfd_vma offset;
372   } tls_ld_got;
373 
374   /* Small local sym to section mapping cache.  */
375   struct sym_sec_cache sym_sec;
376 };
377 
378 /* Get the x86-64 ELF linker hash table from a link_info structure.  */
379 
380 #define elf64_x86_64_hash_table(p) \
381   ((struct elf64_x86_64_link_hash_table *) ((p)->hash))
382 
383 /* Create an entry in an x86-64 ELF linker hash table.	*/
384 
385 static struct bfd_hash_entry *
link_hash_newfunc(struct bfd_hash_entry * entry,struct bfd_hash_table * table,const char * string)386 link_hash_newfunc (struct bfd_hash_entry *entry, struct bfd_hash_table *table,
387 		   const char *string)
388 {
389   /* Allocate the structure if it has not already been allocated by a
390      subclass.  */
391   if (entry == NULL)
392     {
393       entry = bfd_hash_allocate (table,
394 				 sizeof (struct elf64_x86_64_link_hash_entry));
395       if (entry == NULL)
396 	return entry;
397     }
398 
399   /* Call the allocation method of the superclass.  */
400   entry = _bfd_elf_link_hash_newfunc (entry, table, string);
401   if (entry != NULL)
402     {
403       struct elf64_x86_64_link_hash_entry *eh;
404 
405       eh = (struct elf64_x86_64_link_hash_entry *) entry;
406       eh->dyn_relocs = NULL;
407       eh->tls_type = GOT_UNKNOWN;
408     }
409 
410   return entry;
411 }
412 
413 /* Create an X86-64 ELF linker hash table.  */
414 
415 static struct bfd_link_hash_table *
elf64_x86_64_link_hash_table_create(bfd * abfd)416 elf64_x86_64_link_hash_table_create (bfd *abfd)
417 {
418   struct elf64_x86_64_link_hash_table *ret;
419   bfd_size_type amt = sizeof (struct elf64_x86_64_link_hash_table);
420 
421   ret = (struct elf64_x86_64_link_hash_table *) bfd_malloc (amt);
422   if (ret == NULL)
423     return NULL;
424 
425   if (! _bfd_elf_link_hash_table_init (&ret->elf, abfd, link_hash_newfunc))
426     {
427       free (ret);
428       return NULL;
429     }
430 
431   ret->sgot = NULL;
432   ret->sgotplt = NULL;
433   ret->srelgot = NULL;
434   ret->splt = NULL;
435   ret->srelplt = NULL;
436   ret->sdynbss = NULL;
437   ret->srelbss = NULL;
438   ret->sym_sec.abfd = NULL;
439   ret->tls_ld_got.refcount = 0;
440 
441   return &ret->elf.root;
442 }
443 
444 /* Create .got, .gotplt, and .rela.got sections in DYNOBJ, and set up
445    shortcuts to them in our hash table.  */
446 
447 static bfd_boolean
create_got_section(bfd * dynobj,struct bfd_link_info * info)448 create_got_section (bfd *dynobj, struct bfd_link_info *info)
449 {
450   struct elf64_x86_64_link_hash_table *htab;
451 
452   if (! _bfd_elf_create_got_section (dynobj, info))
453     return FALSE;
454 
455   htab = elf64_x86_64_hash_table (info);
456   htab->sgot = bfd_get_section_by_name (dynobj, ".got");
457   htab->sgotplt = bfd_get_section_by_name (dynobj, ".got.plt");
458   if (!htab->sgot || !htab->sgotplt)
459     abort ();
460 
461   htab->srelgot = bfd_make_section (dynobj, ".rela.got");
462   if (htab->srelgot == NULL
463       || ! bfd_set_section_flags (dynobj, htab->srelgot,
464 				  (SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS
465 				   | SEC_IN_MEMORY | SEC_LINKER_CREATED
466 				   | SEC_READONLY))
467       || ! bfd_set_section_alignment (dynobj, htab->srelgot, 3))
468     return FALSE;
469   return TRUE;
470 }
471 
472 /* Create .plt, .rela.plt, .got, .got.plt, .rela.got, .dynbss, and
473    .rela.bss sections in DYNOBJ, and set up shortcuts to them in our
474    hash table.  */
475 
476 static bfd_boolean
elf64_x86_64_create_dynamic_sections(bfd * dynobj,struct bfd_link_info * info)477 elf64_x86_64_create_dynamic_sections (bfd *dynobj, struct bfd_link_info *info)
478 {
479   struct elf64_x86_64_link_hash_table *htab;
480 
481   htab = elf64_x86_64_hash_table (info);
482   if (!htab->sgot && !create_got_section (dynobj, info))
483     return FALSE;
484 
485   if (!_bfd_elf_create_dynamic_sections (dynobj, info))
486     return FALSE;
487 
488   htab->splt = bfd_get_section_by_name (dynobj, ".plt");
489   htab->srelplt = bfd_get_section_by_name (dynobj, ".rela.plt");
490   htab->sdynbss = bfd_get_section_by_name (dynobj, ".dynbss");
491   if (!info->shared)
492     htab->srelbss = bfd_get_section_by_name (dynobj, ".rela.bss");
493 
494   if (!htab->splt || !htab->srelplt || !htab->sdynbss
495       || (!info->shared && !htab->srelbss))
496     abort ();
497 
498   return TRUE;
499 }
500 
501 /* Copy the extra info we tack onto an elf_link_hash_entry.  */
502 
503 static void
elf64_x86_64_copy_indirect_symbol(const struct elf_backend_data * bed,struct elf_link_hash_entry * dir,struct elf_link_hash_entry * ind)504 elf64_x86_64_copy_indirect_symbol (const struct elf_backend_data *bed,
505 				   struct elf_link_hash_entry *dir,
506 				   struct elf_link_hash_entry *ind)
507 {
508   struct elf64_x86_64_link_hash_entry *edir, *eind;
509 
510   edir = (struct elf64_x86_64_link_hash_entry *) dir;
511   eind = (struct elf64_x86_64_link_hash_entry *) ind;
512 
513   if (eind->dyn_relocs != NULL)
514     {
515       if (edir->dyn_relocs != NULL)
516 	{
517 	  struct elf64_x86_64_dyn_relocs **pp;
518 	  struct elf64_x86_64_dyn_relocs *p;
519 
520 	  if (ind->root.type == bfd_link_hash_indirect)
521 	    abort ();
522 
523 	  /* Add reloc counts against the weak sym to the strong sym
524 	     list.  Merge any entries against the same section.  */
525 	  for (pp = &eind->dyn_relocs; (p = *pp) != NULL; )
526 	    {
527 	      struct elf64_x86_64_dyn_relocs *q;
528 
529 	      for (q = edir->dyn_relocs; q != NULL; q = q->next)
530 		if (q->sec == p->sec)
531 		  {
532 		    q->pc_count += p->pc_count;
533 		    q->count += p->count;
534 		    *pp = p->next;
535 		    break;
536 		  }
537 	      if (q == NULL)
538 		pp = &p->next;
539 	    }
540 	  *pp = edir->dyn_relocs;
541 	}
542 
543       edir->dyn_relocs = eind->dyn_relocs;
544       eind->dyn_relocs = NULL;
545     }
546 
547   if (ind->root.type == bfd_link_hash_indirect
548       && dir->got.refcount <= 0)
549     {
550       edir->tls_type = eind->tls_type;
551       eind->tls_type = GOT_UNKNOWN;
552     }
553 
554   if (ELIMINATE_COPY_RELOCS
555       && ind->root.type != bfd_link_hash_indirect
556       && (dir->elf_link_hash_flags & ELF_LINK_HASH_DYNAMIC_ADJUSTED) != 0)
557     /* If called to transfer flags for a weakdef during processing
558        of elf_adjust_dynamic_symbol, don't copy ELF_LINK_NON_GOT_REF.
559        We clear it ourselves for ELIMINATE_COPY_RELOCS.  */
560     dir->elf_link_hash_flags |=
561       (ind->elf_link_hash_flags & (ELF_LINK_HASH_REF_DYNAMIC
562 				   | ELF_LINK_HASH_REF_REGULAR
563 				   | ELF_LINK_HASH_REF_REGULAR_NONWEAK
564 				   | ELF_LINK_HASH_NEEDS_PLT));
565   else
566     _bfd_elf_link_hash_copy_indirect (bed, dir, ind);
567 }
568 
569 static bfd_boolean
elf64_x86_64_mkobject(bfd * abfd)570 elf64_x86_64_mkobject (bfd *abfd)
571 {
572   bfd_size_type amt = sizeof (struct elf64_x86_64_obj_tdata);
573   abfd->tdata.any = bfd_zalloc (abfd, amt);
574   if (abfd->tdata.any == NULL)
575     return FALSE;
576   return TRUE;
577 }
578 
579 static bfd_boolean
elf64_x86_64_elf_object_p(bfd * abfd)580 elf64_x86_64_elf_object_p (bfd *abfd)
581 {
582   /* Set the right machine number for an x86-64 elf64 file.  */
583   bfd_default_set_arch_mach (abfd, bfd_arch_i386, bfd_mach_x86_64);
584   return TRUE;
585 }
586 
587 static int
elf64_x86_64_tls_transition(struct bfd_link_info * info,int r_type,int is_local)588 elf64_x86_64_tls_transition (struct bfd_link_info *info, int r_type, int is_local)
589 {
590   if (info->shared)
591     return r_type;
592 
593   switch (r_type)
594     {
595     case R_X86_64_TLSGD:
596     case R_X86_64_GOTTPOFF:
597       if (is_local)
598 	return R_X86_64_TPOFF32;
599       return R_X86_64_GOTTPOFF;
600     case R_X86_64_TLSLD:
601       return R_X86_64_TPOFF32;
602     }
603 
604    return r_type;
605 }
606 
607 /* Look through the relocs for a section during the first phase, and
608    calculate needed space in the global offset table, procedure
609    linkage table, and dynamic reloc sections.  */
610 
611 static bfd_boolean
elf64_x86_64_check_relocs(bfd * abfd,struct bfd_link_info * info,asection * sec,const Elf_Internal_Rela * relocs)612 elf64_x86_64_check_relocs (bfd *abfd, struct bfd_link_info *info, asection *sec,
613 			   const Elf_Internal_Rela *relocs)
614 {
615   struct elf64_x86_64_link_hash_table *htab;
616   Elf_Internal_Shdr *symtab_hdr;
617   struct elf_link_hash_entry **sym_hashes;
618   const Elf_Internal_Rela *rel;
619   const Elf_Internal_Rela *rel_end;
620   asection *sreloc;
621 
622   if (info->relocatable)
623     return TRUE;
624 
625   htab = elf64_x86_64_hash_table (info);
626   symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
627   sym_hashes = elf_sym_hashes (abfd);
628 
629   sreloc = NULL;
630 
631   rel_end = relocs + sec->reloc_count;
632   for (rel = relocs; rel < rel_end; rel++)
633     {
634       unsigned int r_type;
635       unsigned long r_symndx;
636       struct elf_link_hash_entry *h;
637 
638       r_symndx = ELF64_R_SYM (rel->r_info);
639       r_type = ELF64_R_TYPE (rel->r_info);
640 
641       if (r_symndx >= NUM_SHDR_ENTRIES (symtab_hdr))
642 	{
643 	  (*_bfd_error_handler) (_("%s: bad symbol index: %d"),
644 				 bfd_archive_filename (abfd),
645 				 r_symndx);
646 	  return FALSE;
647 	}
648 
649       if (r_symndx < symtab_hdr->sh_info)
650 	h = NULL;
651       else
652 	h = sym_hashes[r_symndx - symtab_hdr->sh_info];
653 
654       r_type = elf64_x86_64_tls_transition (info, r_type, h == NULL);
655       switch (r_type)
656 	{
657 	case R_X86_64_TLSLD:
658 	  htab->tls_ld_got.refcount += 1;
659 	  goto create_got;
660 
661 	case R_X86_64_TPOFF32:
662 	  if (info->shared)
663 	    {
664 	      (*_bfd_error_handler)
665 		(_("%s: relocation %s can not be used when making a shared object; recompile with -fPIC"),
666 		 bfd_archive_filename (abfd),
667 		 x86_64_elf_howto_table[r_type].name);
668 	      bfd_set_error (bfd_error_bad_value);
669 	      return FALSE;
670 	    }
671 	  break;
672 
673 	case R_X86_64_GOTTPOFF:
674 	  if (info->shared)
675 	    info->flags |= DF_STATIC_TLS;
676 	  /* Fall through */
677 
678 	case R_X86_64_GOT32:
679 	case R_X86_64_GOTPCREL:
680 	case R_X86_64_TLSGD:
681 	  /* This symbol requires a global offset table entry.	*/
682 	  {
683 	    int tls_type, old_tls_type;
684 
685 	    switch (r_type)
686 	      {
687 	      default: tls_type = GOT_NORMAL; break;
688 	      case R_X86_64_TLSGD: tls_type = GOT_TLS_GD; break;
689 	      case R_X86_64_GOTTPOFF: tls_type = GOT_TLS_IE; break;
690 	      }
691 
692 	    if (h != NULL)
693 	      {
694 		h->got.refcount += 1;
695 		old_tls_type = elf64_x86_64_hash_entry (h)->tls_type;
696 	      }
697 	    else
698 	      {
699 		bfd_signed_vma *local_got_refcounts;
700 
701 		/* This is a global offset table entry for a local symbol.  */
702 		local_got_refcounts = elf_local_got_refcounts (abfd);
703 		if (local_got_refcounts == NULL)
704 		  {
705 		    bfd_size_type size;
706 
707 		    size = symtab_hdr->sh_info;
708 		    size *= sizeof (bfd_signed_vma) + sizeof (char);
709 		    local_got_refcounts = ((bfd_signed_vma *)
710 					   bfd_zalloc (abfd, size));
711 		    if (local_got_refcounts == NULL)
712 		      return FALSE;
713 		    elf_local_got_refcounts (abfd) = local_got_refcounts;
714 		    elf64_x86_64_local_got_tls_type (abfd)
715 		      = (char *) (local_got_refcounts + symtab_hdr->sh_info);
716 		  }
717 		local_got_refcounts[r_symndx] += 1;
718 		old_tls_type
719 		  = elf64_x86_64_local_got_tls_type (abfd) [r_symndx];
720 	      }
721 
722 	    /* If a TLS symbol is accessed using IE at least once,
723 	       there is no point to use dynamic model for it.  */
724 	    if (old_tls_type != tls_type && old_tls_type != GOT_UNKNOWN
725 		&& (old_tls_type != GOT_TLS_GD || tls_type != GOT_TLS_IE))
726 	      {
727 		if (old_tls_type == GOT_TLS_IE && tls_type == GOT_TLS_GD)
728 		  tls_type = old_tls_type;
729 		else
730 		  {
731 		    (*_bfd_error_handler)
732 		      (_("%s: %s' accessed both as normal and thread local symbol"),
733 		       bfd_archive_filename (abfd),
734 		       h ? h->root.root.string : "<local>");
735 		    return FALSE;
736 		  }
737 	      }
738 
739 	    if (old_tls_type != tls_type)
740 	      {
741 		if (h != NULL)
742 		  elf64_x86_64_hash_entry (h)->tls_type = tls_type;
743 		else
744 		  elf64_x86_64_local_got_tls_type (abfd) [r_symndx] = tls_type;
745 	      }
746 	  }
747 	  /* Fall through */
748 
749 	  //case R_X86_64_GOTPCREL:
750 	create_got:
751 	  if (htab->sgot == NULL)
752 	    {
753 	      if (htab->elf.dynobj == NULL)
754 		htab->elf.dynobj = abfd;
755 	      if (!create_got_section (htab->elf.dynobj, info))
756 		return FALSE;
757 	    }
758 	  break;
759 
760 	case R_X86_64_PLT32:
761 	  /* This symbol requires a procedure linkage table entry.  We
762 	     actually build the entry in adjust_dynamic_symbol,
763 	     because this might be a case of linking PIC code which is
764 	     never referenced by a dynamic object, in which case we
765 	     don't need to generate a procedure linkage table entry
766 	     after all.	 */
767 
768 	  /* If this is a local symbol, we resolve it directly without
769 	     creating a procedure linkage table entry.	*/
770 	  if (h == NULL)
771 	    continue;
772 
773 	  h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_PLT;
774 	  h->plt.refcount += 1;
775 	  break;
776 
777 	case R_X86_64_8:
778 	case R_X86_64_16:
779 	case R_X86_64_32:
780 	case R_X86_64_32S:
781 	  /* Let's help debug shared library creation.  These relocs
782 	     cannot be used in shared libs.  Don't error out for
783 	     sections we don't care about, such as debug sections or
784 	     non-constant sections.  */
785 	  if (info->shared
786 	      && (sec->flags & SEC_ALLOC) != 0
787 	      && (sec->flags & SEC_READONLY) != 0)
788 	    {
789 	      (*_bfd_error_handler)
790 		(_("%s: relocation %s can not be used when making a shared object; recompile with -fPIC"),
791 		 bfd_archive_filename (abfd),
792 		 x86_64_elf_howto_table[r_type].name);
793 	      bfd_set_error (bfd_error_bad_value);
794 	      return FALSE;
795 	    }
796 	  /* Fall through.  */
797 
798 	case R_X86_64_PC8:
799 	case R_X86_64_PC16:
800 	case R_X86_64_PC32:
801 	case R_X86_64_64:
802 	  if (h != NULL && !info->shared)
803 	    {
804 	      /* If this reloc is in a read-only section, we might
805 		 need a copy reloc.  We can't check reliably at this
806 		 stage whether the section is read-only, as input
807 		 sections have not yet been mapped to output sections.
808 		 Tentatively set the flag for now, and correct in
809 		 adjust_dynamic_symbol.  */
810 	      h->elf_link_hash_flags |= ELF_LINK_NON_GOT_REF;
811 
812 	      /* We may need a .plt entry if the function this reloc
813 		 refers to is in a shared lib.  */
814 	      h->plt.refcount += 1;
815 	    }
816 
817 	  /* If we are creating a shared library, and this is a reloc
818 	     against a global symbol, or a non PC relative reloc
819 	     against a local symbol, then we need to copy the reloc
820 	     into the shared library.  However, if we are linking with
821 	     -Bsymbolic, we do not need to copy a reloc against a
822 	     global symbol which is defined in an object we are
823 	     including in the link (i.e., DEF_REGULAR is set).	At
824 	     this point we have not seen all the input files, so it is
825 	     possible that DEF_REGULAR is not set now but will be set
826 	     later (it is never cleared).  In case of a weak definition,
827 	     DEF_REGULAR may be cleared later by a strong definition in
828 	     a shared library.  We account for that possibility below by
829 	     storing information in the relocs_copied field of the hash
830 	     table entry.  A similar situation occurs when creating
831 	     shared libraries and symbol visibility changes render the
832 	     symbol local.
833 
834 	     If on the other hand, we are creating an executable, we
835 	     may need to keep relocations for symbols satisfied by a
836 	     dynamic library if we manage to avoid copy relocs for the
837 	     symbol.  */
838 	  if ((info->shared
839 	       && (sec->flags & SEC_ALLOC) != 0
840 	       && (((r_type != R_X86_64_PC8)
841 		    && (r_type != R_X86_64_PC16)
842 		    && (r_type != R_X86_64_PC32))
843 		   || (h != NULL
844 		       && (! info->symbolic
845 			   || h->root.type == bfd_link_hash_defweak
846 			   || (h->elf_link_hash_flags
847 			       & ELF_LINK_HASH_DEF_REGULAR) == 0))))
848 	      || (ELIMINATE_COPY_RELOCS
849 		  && !info->shared
850 		  && (sec->flags & SEC_ALLOC) != 0
851 		  && h != NULL
852 		  && (h->root.type == bfd_link_hash_defweak
853 		      || (h->elf_link_hash_flags
854 			  & ELF_LINK_HASH_DEF_REGULAR) == 0)))
855 	    {
856 	      struct elf64_x86_64_dyn_relocs *p;
857 	      struct elf64_x86_64_dyn_relocs **head;
858 
859 	      /* We must copy these reloc types into the output file.
860 		 Create a reloc section in dynobj and make room for
861 		 this reloc.  */
862 	      if (sreloc == NULL)
863 		{
864 		  const char *name;
865 		  bfd *dynobj;
866 
867 		  name = (bfd_elf_string_from_elf_section
868 			  (abfd,
869 			   elf_elfheader (abfd)->e_shstrndx,
870 			   elf_section_data (sec)->rel_hdr.sh_name));
871 		  if (name == NULL)
872 		    return FALSE;
873 
874 		  if (strncmp (name, ".rela", 5) != 0
875 		      || strcmp (bfd_get_section_name (abfd, sec),
876 				 name + 5) != 0)
877 		    {
878 		      (*_bfd_error_handler)
879 			(_("%s: bad relocation section name `%s\'"),
880 			 bfd_archive_filename (abfd), name);
881 		    }
882 
883 		  if (htab->elf.dynobj == NULL)
884 		    htab->elf.dynobj = abfd;
885 
886 		  dynobj = htab->elf.dynobj;
887 
888 		  sreloc = bfd_get_section_by_name (dynobj, name);
889 		  if (sreloc == NULL)
890 		    {
891 		      flagword flags;
892 
893 		      sreloc = bfd_make_section (dynobj, name);
894 		      flags = (SEC_HAS_CONTENTS | SEC_READONLY
895 			       | SEC_IN_MEMORY | SEC_LINKER_CREATED);
896 		      if ((sec->flags & SEC_ALLOC) != 0)
897 			flags |= SEC_ALLOC | SEC_LOAD;
898 		      if (sreloc == NULL
899 			  || ! bfd_set_section_flags (dynobj, sreloc, flags)
900 			  || ! bfd_set_section_alignment (dynobj, sreloc, 3))
901 			return FALSE;
902 		    }
903 		  elf_section_data (sec)->sreloc = sreloc;
904 		}
905 
906 	      /* If this is a global symbol, we count the number of
907 		 relocations we need for this symbol.  */
908 	      if (h != NULL)
909 		{
910 		  head = &((struct elf64_x86_64_link_hash_entry *) h)->dyn_relocs;
911 		}
912 	      else
913 		{
914 		  /* Track dynamic relocs needed for local syms too.
915 		     We really need local syms available to do this
916 		     easily.  Oh well.  */
917 
918 		  asection *s;
919 		  s = bfd_section_from_r_symndx (abfd, &htab->sym_sec,
920 						 sec, r_symndx);
921 		  if (s == NULL)
922 		    return FALSE;
923 
924 		  head = ((struct elf64_x86_64_dyn_relocs **)
925 			  &elf_section_data (s)->local_dynrel);
926 		}
927 
928 	      p = *head;
929 	      if (p == NULL || p->sec != sec)
930 		{
931 		  bfd_size_type amt = sizeof *p;
932 		  p = ((struct elf64_x86_64_dyn_relocs *)
933 		       bfd_alloc (htab->elf.dynobj, amt));
934 		  if (p == NULL)
935 		    return FALSE;
936 		  p->next = *head;
937 		  *head = p;
938 		  p->sec = sec;
939 		  p->count = 0;
940 		  p->pc_count = 0;
941 		}
942 
943 	      p->count += 1;
944 	      if (r_type == R_X86_64_PC8
945 		  || r_type == R_X86_64_PC16
946 		  || r_type == R_X86_64_PC32)
947 		p->pc_count += 1;
948 	    }
949 	  break;
950 
951 	  /* This relocation describes the C++ object vtable hierarchy.
952 	     Reconstruct it for later use during GC.  */
953 	case R_X86_64_GNU_VTINHERIT:
954 	  if (!bfd_elf_gc_record_vtinherit (abfd, sec, h, rel->r_offset))
955 	    return FALSE;
956 	  break;
957 
958 	  /* This relocation describes which C++ vtable entries are actually
959 	     used.  Record for later use during GC.  */
960 	case R_X86_64_GNU_VTENTRY:
961 	  if (!bfd_elf_gc_record_vtentry (abfd, sec, h, rel->r_addend))
962 	    return FALSE;
963 	  break;
964 
965 	default:
966 	  break;
967 	}
968     }
969 
970   return TRUE;
971 }
972 
973 /* Return the section that should be marked against GC for a given
974    relocation.	*/
975 
976 static asection *
elf64_x86_64_gc_mark_hook(asection * sec,struct bfd_link_info * info ATTRIBUTE_UNUSED,Elf_Internal_Rela * rel,struct elf_link_hash_entry * h,Elf_Internal_Sym * sym)977 elf64_x86_64_gc_mark_hook (asection *sec,
978 			   struct bfd_link_info *info ATTRIBUTE_UNUSED,
979 			   Elf_Internal_Rela *rel,
980 			   struct elf_link_hash_entry *h,
981 			   Elf_Internal_Sym *sym)
982 {
983   if (h != NULL)
984     {
985       switch (ELF64_R_TYPE (rel->r_info))
986 	{
987 	case R_X86_64_GNU_VTINHERIT:
988 	case R_X86_64_GNU_VTENTRY:
989 	  break;
990 
991 	default:
992 	  switch (h->root.type)
993 	    {
994 	    case bfd_link_hash_defined:
995 	    case bfd_link_hash_defweak:
996 	      return h->root.u.def.section;
997 
998 	    case bfd_link_hash_common:
999 	      return h->root.u.c.p->section;
1000 
1001 	    default:
1002 	      break;
1003 	    }
1004 	}
1005     }
1006   else
1007     return bfd_section_from_elf_index (sec->owner, sym->st_shndx);
1008 
1009   return NULL;
1010 }
1011 
1012 /* Update the got entry reference counts for the section being removed.	 */
1013 
1014 static bfd_boolean
elf64_x86_64_gc_sweep_hook(bfd * abfd,struct bfd_link_info * info,asection * sec,const Elf_Internal_Rela * relocs)1015 elf64_x86_64_gc_sweep_hook (bfd *abfd, struct bfd_link_info *info,
1016 			    asection *sec, const Elf_Internal_Rela *relocs)
1017 {
1018   Elf_Internal_Shdr *symtab_hdr;
1019   struct elf_link_hash_entry **sym_hashes;
1020   bfd_signed_vma *local_got_refcounts;
1021   const Elf_Internal_Rela *rel, *relend;
1022 
1023   elf_section_data (sec)->local_dynrel = NULL;
1024 
1025   symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
1026   sym_hashes = elf_sym_hashes (abfd);
1027   local_got_refcounts = elf_local_got_refcounts (abfd);
1028 
1029   relend = relocs + sec->reloc_count;
1030   for (rel = relocs; rel < relend; rel++)
1031     {
1032       unsigned long r_symndx;
1033       unsigned int r_type;
1034       struct elf_link_hash_entry *h = NULL;
1035 
1036       r_symndx = ELF64_R_SYM (rel->r_info);
1037       if (r_symndx >= symtab_hdr->sh_info)
1038 	{
1039 	  struct elf64_x86_64_link_hash_entry *eh;
1040 	  struct elf64_x86_64_dyn_relocs **pp;
1041 	  struct elf64_x86_64_dyn_relocs *p;
1042 
1043 	  h = sym_hashes[r_symndx - symtab_hdr->sh_info];
1044 	  eh = (struct elf64_x86_64_link_hash_entry *) h;
1045 
1046 	  for (pp = &eh->dyn_relocs; (p = *pp) != NULL; pp = &p->next)
1047 	    if (p->sec == sec)
1048 	      {
1049 		/* Everything must go for SEC.  */
1050 		*pp = p->next;
1051 		break;
1052 	      }
1053 	}
1054 
1055       r_type = ELF64_R_TYPE (rel->r_info);
1056       r_type = elf64_x86_64_tls_transition (info, r_type, h != NULL);
1057       switch (r_type)
1058 	{
1059 	case R_X86_64_TLSLD:
1060 	  if (elf64_x86_64_hash_table (info)->tls_ld_got.refcount > 0)
1061 	    elf64_x86_64_hash_table (info)->tls_ld_got.refcount -= 1;
1062 	  break;
1063 
1064 	case R_X86_64_TLSGD:
1065 	case R_X86_64_GOTTPOFF:
1066 	case R_X86_64_GOT32:
1067 	case R_X86_64_GOTPCREL:
1068 	  if (h != NULL)
1069 	    {
1070 	      if (h->got.refcount > 0)
1071 		h->got.refcount -= 1;
1072 	    }
1073 	  else if (local_got_refcounts != NULL)
1074 	    {
1075 	      if (local_got_refcounts[r_symndx] > 0)
1076 		local_got_refcounts[r_symndx] -= 1;
1077 	    }
1078 	  break;
1079 
1080 	case R_X86_64_8:
1081 	case R_X86_64_16:
1082 	case R_X86_64_32:
1083 	case R_X86_64_64:
1084 	case R_X86_64_32S:
1085 	case R_X86_64_PC8:
1086 	case R_X86_64_PC16:
1087 	case R_X86_64_PC32:
1088 	  if (info->shared)
1089 	    break;
1090 	  /* Fall thru */
1091 
1092 	case R_X86_64_PLT32:
1093 	  if (h != NULL)
1094 	    {
1095 	      if (h->plt.refcount > 0)
1096 		h->plt.refcount -= 1;
1097 	    }
1098 	  break;
1099 
1100 	default:
1101 	  break;
1102 	}
1103     }
1104 
1105   return TRUE;
1106 }
1107 
1108 /* Adjust a symbol defined by a dynamic object and referenced by a
1109    regular object.  The current definition is in some section of the
1110    dynamic object, but we're not including those sections.  We have to
1111    change the definition to something the rest of the link can
1112    understand.	*/
1113 
1114 static bfd_boolean
elf64_x86_64_adjust_dynamic_symbol(struct bfd_link_info * info,struct elf_link_hash_entry * h)1115 elf64_x86_64_adjust_dynamic_symbol (struct bfd_link_info *info,
1116 				    struct elf_link_hash_entry *h)
1117 {
1118   struct elf64_x86_64_link_hash_table *htab;
1119   asection *s;
1120   unsigned int power_of_two;
1121 
1122   /* If this is a function, put it in the procedure linkage table.  We
1123      will fill in the contents of the procedure linkage table later,
1124      when we know the address of the .got section.  */
1125   if (h->type == STT_FUNC
1126       || (h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_PLT) != 0)
1127     {
1128       if (h->plt.refcount <= 0
1129 	  || SYMBOL_CALLS_LOCAL (info, h)
1130 	  || (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
1131 	      && h->root.type == bfd_link_hash_undefweak))
1132 	{
1133 	  /* This case can occur if we saw a PLT32 reloc in an input
1134 	     file, but the symbol was never referred to by a dynamic
1135 	     object, or if all references were garbage collected.  In
1136 	     such a case, we don't actually need to build a procedure
1137 	     linkage table, and we can just do a PC32 reloc instead.  */
1138 	  h->plt.offset = (bfd_vma) -1;
1139 	  h->elf_link_hash_flags &= ~ELF_LINK_HASH_NEEDS_PLT;
1140 	}
1141 
1142       return TRUE;
1143     }
1144   else
1145     /* It's possible that we incorrectly decided a .plt reloc was
1146        needed for an R_X86_64_PC32 reloc to a non-function sym in
1147        check_relocs.  We can't decide accurately between function and
1148        non-function syms in check-relocs;  Objects loaded later in
1149        the link may change h->type.  So fix it now.  */
1150     h->plt.offset = (bfd_vma) -1;
1151 
1152   /* If this is a weak symbol, and there is a real definition, the
1153      processor independent code will have arranged for us to see the
1154      real definition first, and we can just use the same value.	 */
1155   if (h->weakdef != NULL)
1156     {
1157       BFD_ASSERT (h->weakdef->root.type == bfd_link_hash_defined
1158 		  || h->weakdef->root.type == bfd_link_hash_defweak);
1159       h->root.u.def.section = h->weakdef->root.u.def.section;
1160       h->root.u.def.value = h->weakdef->root.u.def.value;
1161       if (ELIMINATE_COPY_RELOCS || info->nocopyreloc)
1162 	h->elf_link_hash_flags
1163 	  = ((h->elf_link_hash_flags & ~ELF_LINK_NON_GOT_REF)
1164 	     | (h->weakdef->elf_link_hash_flags & ELF_LINK_NON_GOT_REF));
1165       return TRUE;
1166     }
1167 
1168   /* This is a reference to a symbol defined by a dynamic object which
1169      is not a function.	 */
1170 
1171   /* If we are creating a shared library, we must presume that the
1172      only references to the symbol are via the global offset table.
1173      For such cases we need not do anything here; the relocations will
1174      be handled correctly by relocate_section.	*/
1175   if (info->shared)
1176     return TRUE;
1177 
1178   /* If there are no references to this symbol that do not use the
1179      GOT, we don't need to generate a copy reloc.  */
1180   if ((h->elf_link_hash_flags & ELF_LINK_NON_GOT_REF) == 0)
1181     return TRUE;
1182 
1183   /* If -z nocopyreloc was given, we won't generate them either.  */
1184   if (info->nocopyreloc)
1185     {
1186       h->elf_link_hash_flags &= ~ELF_LINK_NON_GOT_REF;
1187       return TRUE;
1188     }
1189 
1190   if (ELIMINATE_COPY_RELOCS)
1191     {
1192       struct elf64_x86_64_link_hash_entry * eh;
1193       struct elf64_x86_64_dyn_relocs *p;
1194 
1195       eh = (struct elf64_x86_64_link_hash_entry *) h;
1196       for (p = eh->dyn_relocs; p != NULL; p = p->next)
1197 	{
1198 	  s = p->sec->output_section;
1199 	  if (s != NULL && (s->flags & SEC_READONLY) != 0)
1200 	    break;
1201 	}
1202 
1203       /* If we didn't find any dynamic relocs in read-only sections, then
1204 	 we'll be keeping the dynamic relocs and avoiding the copy reloc.  */
1205       if (p == NULL)
1206 	{
1207 	  h->elf_link_hash_flags &= ~ELF_LINK_NON_GOT_REF;
1208 	  return TRUE;
1209 	}
1210     }
1211 
1212   /* We must allocate the symbol in our .dynbss section, which will
1213      become part of the .bss section of the executable.	 There will be
1214      an entry for this symbol in the .dynsym section.  The dynamic
1215      object will contain position independent code, so all references
1216      from the dynamic object to this symbol will go through the global
1217      offset table.  The dynamic linker will use the .dynsym entry to
1218      determine the address it must put in the global offset table, so
1219      both the dynamic object and the regular object will refer to the
1220      same memory location for the variable.  */
1221 
1222   htab = elf64_x86_64_hash_table (info);
1223 
1224   /* We must generate a R_X86_64_COPY reloc to tell the dynamic linker
1225      to copy the initial value out of the dynamic object and into the
1226      runtime process image.  */
1227   if ((h->root.u.def.section->flags & SEC_ALLOC) != 0)
1228     {
1229       htab->srelbss->_raw_size += sizeof (Elf64_External_Rela);
1230       h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_COPY;
1231     }
1232 
1233   /* We need to figure out the alignment required for this symbol.  I
1234      have no idea how ELF linkers handle this.	16-bytes is the size
1235      of the largest type that requires hard alignment -- long double.  */
1236   /* FIXME: This is VERY ugly. Should be fixed for all architectures using
1237      this construct.  */
1238   power_of_two = bfd_log2 (h->size);
1239   if (power_of_two > 4)
1240     power_of_two = 4;
1241 
1242   /* Apply the required alignment.  */
1243   s = htab->sdynbss;
1244   s->_raw_size = BFD_ALIGN (s->_raw_size, (bfd_size_type) (1 << power_of_two));
1245   if (power_of_two > bfd_get_section_alignment (htab->elf.dynobj, s))
1246     {
1247       if (! bfd_set_section_alignment (htab->elf.dynobj, s, power_of_two))
1248 	return FALSE;
1249     }
1250 
1251   /* Define the symbol as being at this point in the section.  */
1252   h->root.u.def.section = s;
1253   h->root.u.def.value = s->_raw_size;
1254 
1255   /* Increment the section size to make room for the symbol.  */
1256   s->_raw_size += h->size;
1257 
1258   return TRUE;
1259 }
1260 
1261 /* Allocate space in .plt, .got and associated reloc sections for
1262    dynamic relocs.  */
1263 
1264 static bfd_boolean
allocate_dynrelocs(struct elf_link_hash_entry * h,void * inf)1265 allocate_dynrelocs (struct elf_link_hash_entry *h, void * inf)
1266 {
1267   struct bfd_link_info *info;
1268   struct elf64_x86_64_link_hash_table *htab;
1269   struct elf64_x86_64_link_hash_entry *eh;
1270   struct elf64_x86_64_dyn_relocs *p;
1271 
1272   if (h->root.type == bfd_link_hash_indirect)
1273     return TRUE;
1274 
1275   if (h->root.type == bfd_link_hash_warning)
1276     h = (struct elf_link_hash_entry *) h->root.u.i.link;
1277 
1278   info = (struct bfd_link_info *) inf;
1279   htab = elf64_x86_64_hash_table (info);
1280 
1281   if (htab->elf.dynamic_sections_created
1282       && h->plt.refcount > 0)
1283     {
1284       /* Make sure this symbol is output as a dynamic symbol.
1285 	 Undefined weak syms won't yet be marked as dynamic.  */
1286       if (h->dynindx == -1
1287 	  && (h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) == 0)
1288 	{
1289 	  if (! bfd_elf_link_record_dynamic_symbol (info, h))
1290 	    return FALSE;
1291 	}
1292 
1293       if (info->shared
1294 	  || WILL_CALL_FINISH_DYNAMIC_SYMBOL (1, 0, h))
1295 	{
1296 	  asection *s = htab->splt;
1297 
1298 	  /* If this is the first .plt entry, make room for the special
1299 	     first entry.  */
1300 	  if (s->_raw_size == 0)
1301 	    s->_raw_size += PLT_ENTRY_SIZE;
1302 
1303 	  h->plt.offset = s->_raw_size;
1304 
1305 	  /* If this symbol is not defined in a regular file, and we are
1306 	     not generating a shared library, then set the symbol to this
1307 	     location in the .plt.  This is required to make function
1308 	     pointers compare as equal between the normal executable and
1309 	     the shared library.  */
1310 	  if (! info->shared
1311 	      && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
1312 	    {
1313 	      h->root.u.def.section = s;
1314 	      h->root.u.def.value = h->plt.offset;
1315 	    }
1316 
1317 	  /* Make room for this entry.  */
1318 	  s->_raw_size += PLT_ENTRY_SIZE;
1319 
1320 	  /* We also need to make an entry in the .got.plt section, which
1321 	     will be placed in the .got section by the linker script.  */
1322 	  htab->sgotplt->_raw_size += GOT_ENTRY_SIZE;
1323 
1324 	  /* We also need to make an entry in the .rela.plt section.  */
1325 	  htab->srelplt->_raw_size += sizeof (Elf64_External_Rela);
1326 	}
1327       else
1328 	{
1329 	  h->plt.offset = (bfd_vma) -1;
1330 	  h->elf_link_hash_flags &= ~ELF_LINK_HASH_NEEDS_PLT;
1331 	}
1332     }
1333   else
1334     {
1335       h->plt.offset = (bfd_vma) -1;
1336       h->elf_link_hash_flags &= ~ELF_LINK_HASH_NEEDS_PLT;
1337     }
1338 
1339   /* If R_X86_64_GOTTPOFF symbol is now local to the binary,
1340      make it a R_X86_64_TPOFF32 requiring no GOT entry.  */
1341   if (h->got.refcount > 0
1342       && !info->shared
1343       && h->dynindx == -1
1344       && elf64_x86_64_hash_entry (h)->tls_type == GOT_TLS_IE)
1345     h->got.offset = (bfd_vma) -1;
1346   else if (h->got.refcount > 0)
1347     {
1348       asection *s;
1349       bfd_boolean dyn;
1350       int tls_type = elf64_x86_64_hash_entry (h)->tls_type;
1351 
1352       /* Make sure this symbol is output as a dynamic symbol.
1353 	 Undefined weak syms won't yet be marked as dynamic.  */
1354       if (h->dynindx == -1
1355 	  && (h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) == 0)
1356 	{
1357 	  if (! bfd_elf_link_record_dynamic_symbol (info, h))
1358 	    return FALSE;
1359 	}
1360 
1361       s = htab->sgot;
1362       h->got.offset = s->_raw_size;
1363       s->_raw_size += GOT_ENTRY_SIZE;
1364       /* R_X86_64_TLSGD needs 2 consecutive GOT slots.  */
1365       if (tls_type == GOT_TLS_GD)
1366 	s->_raw_size += GOT_ENTRY_SIZE;
1367       dyn = htab->elf.dynamic_sections_created;
1368       /* R_X86_64_TLSGD needs one dynamic relocation if local symbol
1369 	 and two if global.
1370 	 R_X86_64_GOTTPOFF needs one dynamic relocation.  */
1371       if ((tls_type == GOT_TLS_GD && h->dynindx == -1)
1372 	  || tls_type == GOT_TLS_IE)
1373 	htab->srelgot->_raw_size += sizeof (Elf64_External_Rela);
1374       else if (tls_type == GOT_TLS_GD)
1375 	htab->srelgot->_raw_size += 2 * sizeof (Elf64_External_Rela);
1376       else if ((ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
1377 		|| h->root.type != bfd_link_hash_undefweak)
1378 	       && (info->shared
1379 		   || WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn, 0, h)))
1380 	htab->srelgot->_raw_size += sizeof (Elf64_External_Rela);
1381     }
1382   else
1383     h->got.offset = (bfd_vma) -1;
1384 
1385   eh = (struct elf64_x86_64_link_hash_entry *) h;
1386   if (eh->dyn_relocs == NULL)
1387     return TRUE;
1388 
1389   /* In the shared -Bsymbolic case, discard space allocated for
1390      dynamic pc-relative relocs against symbols which turn out to be
1391      defined in regular objects.  For the normal shared case, discard
1392      space for pc-relative relocs that have become local due to symbol
1393      visibility changes.  */
1394 
1395   if (info->shared)
1396     {
1397       /* Relocs that use pc_count are those that appear on a call
1398 	 insn, or certain REL relocs that can generated via assembly.
1399 	 We want calls to protected symbols to resolve directly to the
1400 	 function rather than going via the plt.  If people want
1401 	 function pointer comparisons to work as expected then they
1402 	 should avoid writing weird assembly.  */
1403       if (SYMBOL_CALLS_LOCAL (info, h))
1404 	{
1405 	  struct elf64_x86_64_dyn_relocs **pp;
1406 
1407 	  for (pp = &eh->dyn_relocs; (p = *pp) != NULL; )
1408 	    {
1409 	      p->count -= p->pc_count;
1410 	      p->pc_count = 0;
1411 	      if (p->count == 0)
1412 		*pp = p->next;
1413 	      else
1414 		pp = &p->next;
1415 	    }
1416 	}
1417 
1418       /* Also discard relocs on undefined weak syms with non-default
1419 	 visibility.  */
1420       if (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
1421 	  && h->root.type == bfd_link_hash_undefweak)
1422 	eh->dyn_relocs = NULL;
1423     }
1424   else if (ELIMINATE_COPY_RELOCS)
1425     {
1426       /* For the non-shared case, discard space for relocs against
1427 	 symbols which turn out to need copy relocs or are not
1428 	 dynamic.  */
1429 
1430       if ((h->elf_link_hash_flags & ELF_LINK_NON_GOT_REF) == 0
1431 	  && (((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0
1432 	       && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
1433 	      || (htab->elf.dynamic_sections_created
1434 		  && (h->root.type == bfd_link_hash_undefweak
1435 		      || h->root.type == bfd_link_hash_undefined))))
1436 	{
1437 	  /* Make sure this symbol is output as a dynamic symbol.
1438 	     Undefined weak syms won't yet be marked as dynamic.  */
1439 	  if (h->dynindx == -1
1440 	      && (h->elf_link_hash_flags & ELF_LINK_FORCED_LOCAL) == 0)
1441 	    {
1442 	      if (! bfd_elf_link_record_dynamic_symbol (info, h))
1443 		return FALSE;
1444 	    }
1445 
1446 	  /* If that succeeded, we know we'll be keeping all the
1447 	     relocs.  */
1448 	  if (h->dynindx != -1)
1449 	    goto keep;
1450 	}
1451 
1452       eh->dyn_relocs = NULL;
1453 
1454     keep: ;
1455     }
1456 
1457   /* Finally, allocate space.  */
1458   for (p = eh->dyn_relocs; p != NULL; p = p->next)
1459     {
1460       asection *sreloc = elf_section_data (p->sec)->sreloc;
1461       sreloc->_raw_size += p->count * sizeof (Elf64_External_Rela);
1462     }
1463 
1464   return TRUE;
1465 }
1466 
1467 /* Find any dynamic relocs that apply to read-only sections.  */
1468 
1469 static bfd_boolean
readonly_dynrelocs(struct elf_link_hash_entry * h,void * inf)1470 readonly_dynrelocs (struct elf_link_hash_entry *h, void * inf)
1471 {
1472   struct elf64_x86_64_link_hash_entry *eh;
1473   struct elf64_x86_64_dyn_relocs *p;
1474 
1475   if (h->root.type == bfd_link_hash_warning)
1476     h = (struct elf_link_hash_entry *) h->root.u.i.link;
1477 
1478   eh = (struct elf64_x86_64_link_hash_entry *) h;
1479   for (p = eh->dyn_relocs; p != NULL; p = p->next)
1480     {
1481       asection *s = p->sec->output_section;
1482 
1483       if (s != NULL && (s->flags & SEC_READONLY) != 0)
1484 	{
1485 	  struct bfd_link_info *info = (struct bfd_link_info *) inf;
1486 
1487 	  info->flags |= DF_TEXTREL;
1488 
1489 	  /* Not an error, just cut short the traversal.  */
1490 	  return FALSE;
1491 	}
1492     }
1493   return TRUE;
1494 }
1495 
1496 /* Set the sizes of the dynamic sections.  */
1497 
1498 static bfd_boolean
elf64_x86_64_size_dynamic_sections(bfd * output_bfd ATTRIBUTE_UNUSED,struct bfd_link_info * info)1499 elf64_x86_64_size_dynamic_sections (bfd *output_bfd ATTRIBUTE_UNUSED,
1500 				    struct bfd_link_info *info)
1501 {
1502   struct elf64_x86_64_link_hash_table *htab;
1503   bfd *dynobj;
1504   asection *s;
1505   bfd_boolean relocs;
1506   bfd *ibfd;
1507 
1508   htab = elf64_x86_64_hash_table (info);
1509   dynobj = htab->elf.dynobj;
1510   if (dynobj == NULL)
1511     abort ();
1512 
1513   if (htab->elf.dynamic_sections_created)
1514     {
1515       /* Set the contents of the .interp section to the interpreter.  */
1516       if (info->executable)
1517 	{
1518 	  s = bfd_get_section_by_name (dynobj, ".interp");
1519 	  if (s == NULL)
1520 	    abort ();
1521 	  s->_raw_size = sizeof ELF_DYNAMIC_INTERPRETER;
1522 	  s->contents = (unsigned char *) ELF_DYNAMIC_INTERPRETER;
1523 	}
1524     }
1525 
1526   /* Set up .got offsets for local syms, and space for local dynamic
1527      relocs.  */
1528   for (ibfd = info->input_bfds; ibfd != NULL; ibfd = ibfd->link_next)
1529     {
1530       bfd_signed_vma *local_got;
1531       bfd_signed_vma *end_local_got;
1532       char *local_tls_type;
1533       bfd_size_type locsymcount;
1534       Elf_Internal_Shdr *symtab_hdr;
1535       asection *srel;
1536 
1537       if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour)
1538 	continue;
1539 
1540       for (s = ibfd->sections; s != NULL; s = s->next)
1541 	{
1542 	  struct elf64_x86_64_dyn_relocs *p;
1543 
1544 	  for (p = *((struct elf64_x86_64_dyn_relocs **)
1545 		     &elf_section_data (s)->local_dynrel);
1546 	       p != NULL;
1547 	       p = p->next)
1548 	    {
1549 	      if (!bfd_is_abs_section (p->sec)
1550 		  && bfd_is_abs_section (p->sec->output_section))
1551 		{
1552 		  /* Input section has been discarded, either because
1553 		     it is a copy of a linkonce section or due to
1554 		     linker script /DISCARD/, so we'll be discarding
1555 		     the relocs too.  */
1556 		}
1557 	      else if (p->count != 0)
1558 		{
1559 		  srel = elf_section_data (p->sec)->sreloc;
1560 		  srel->_raw_size += p->count * sizeof (Elf64_External_Rela);
1561 		  if ((p->sec->output_section->flags & SEC_READONLY) != 0)
1562 		    info->flags |= DF_TEXTREL;
1563 
1564 		}
1565 	    }
1566 	}
1567 
1568       local_got = elf_local_got_refcounts (ibfd);
1569       if (!local_got)
1570 	continue;
1571 
1572       symtab_hdr = &elf_tdata (ibfd)->symtab_hdr;
1573       locsymcount = symtab_hdr->sh_info;
1574       end_local_got = local_got + locsymcount;
1575       local_tls_type = elf64_x86_64_local_got_tls_type (ibfd);
1576       s = htab->sgot;
1577       srel = htab->srelgot;
1578       for (; local_got < end_local_got; ++local_got, ++local_tls_type)
1579 	{
1580 	  if (*local_got > 0)
1581 	    {
1582 	      *local_got = s->_raw_size;
1583 	      s->_raw_size += GOT_ENTRY_SIZE;
1584 	      if (*local_tls_type == GOT_TLS_GD)
1585 		s->_raw_size += GOT_ENTRY_SIZE;
1586 	      if (info->shared
1587 		  || *local_tls_type == GOT_TLS_GD
1588 		  || *local_tls_type == GOT_TLS_IE)
1589 		srel->_raw_size += sizeof (Elf64_External_Rela);
1590 	    }
1591 	  else
1592 	    *local_got = (bfd_vma) -1;
1593 	}
1594     }
1595 
1596   if (htab->tls_ld_got.refcount > 0)
1597     {
1598       /* Allocate 2 got entries and 1 dynamic reloc for R_X86_64_TLSLD
1599 	 relocs.  */
1600       htab->tls_ld_got.offset = htab->sgot->_raw_size;
1601       htab->sgot->_raw_size += 2 * GOT_ENTRY_SIZE;
1602       htab->srelgot->_raw_size += sizeof (Elf64_External_Rela);
1603     }
1604   else
1605     htab->tls_ld_got.offset = -1;
1606 
1607   /* Allocate global sym .plt and .got entries, and space for global
1608      sym dynamic relocs.  */
1609   elf_link_hash_traverse (&htab->elf, allocate_dynrelocs, (PTR) info);
1610 
1611   /* We now have determined the sizes of the various dynamic sections.
1612      Allocate memory for them.  */
1613   relocs = FALSE;
1614   for (s = dynobj->sections; s != NULL; s = s->next)
1615     {
1616       if ((s->flags & SEC_LINKER_CREATED) == 0)
1617 	continue;
1618 
1619       if (s == htab->splt
1620 	  || s == htab->sgot
1621 	  || s == htab->sgotplt)
1622 	{
1623 	  /* Strip this section if we don't need it; see the
1624 	     comment below.  */
1625 	}
1626       else if (strncmp (bfd_get_section_name (dynobj, s), ".rela", 5) == 0)
1627 	{
1628 	  if (s->_raw_size != 0 && s != htab->srelplt)
1629 	    relocs = TRUE;
1630 
1631 	  /* We use the reloc_count field as a counter if we need
1632 	     to copy relocs into the output file.  */
1633 	  s->reloc_count = 0;
1634 	}
1635       else
1636 	{
1637 	  /* It's not one of our sections, so don't allocate space.  */
1638 	  continue;
1639 	}
1640 
1641       if (s->_raw_size == 0)
1642 	{
1643 	  /* If we don't need this section, strip it from the
1644 	     output file.  This is mostly to handle .rela.bss and
1645 	     .rela.plt.  We must create both sections in
1646 	     create_dynamic_sections, because they must be created
1647 	     before the linker maps input sections to output
1648 	     sections.  The linker does that before
1649 	     adjust_dynamic_symbol is called, and it is that
1650 	     function which decides whether anything needs to go
1651 	     into these sections.  */
1652 
1653 	  _bfd_strip_section_from_output (info, s);
1654 	  continue;
1655 	}
1656 
1657       /* Allocate memory for the section contents.  We use bfd_zalloc
1658 	 here in case unused entries are not reclaimed before the
1659 	 section's contents are written out.  This should not happen,
1660 	 but this way if it does, we get a R_X86_64_NONE reloc instead
1661 	 of garbage.  */
1662       s->contents = (bfd_byte *) bfd_zalloc (dynobj, s->_raw_size);
1663       if (s->contents == NULL)
1664 	return FALSE;
1665     }
1666 
1667   if (htab->elf.dynamic_sections_created)
1668     {
1669       /* Add some entries to the .dynamic section.  We fill in the
1670 	 values later, in elf64_x86_64_finish_dynamic_sections, but we
1671 	 must add the entries now so that we get the correct size for
1672 	 the .dynamic section.	The DT_DEBUG entry is filled in by the
1673 	 dynamic linker and used by the debugger.  */
1674 #define add_dynamic_entry(TAG, VAL) \
1675   _bfd_elf_add_dynamic_entry (info, TAG, VAL)
1676 
1677       if (info->executable)
1678 	{
1679 	  if (!add_dynamic_entry (DT_DEBUG, 0))
1680 	    return FALSE;
1681 	}
1682 
1683       if (htab->splt->_raw_size != 0)
1684 	{
1685 	  if (!add_dynamic_entry (DT_PLTGOT, 0)
1686 	      || !add_dynamic_entry (DT_PLTRELSZ, 0)
1687 	      || !add_dynamic_entry (DT_PLTREL, DT_RELA)
1688 	      || !add_dynamic_entry (DT_JMPREL, 0))
1689 	    return FALSE;
1690 	}
1691 
1692       if (relocs)
1693 	{
1694 	  if (!add_dynamic_entry (DT_RELA, 0)
1695 	      || !add_dynamic_entry (DT_RELASZ, 0)
1696 	      || !add_dynamic_entry (DT_RELAENT, sizeof (Elf64_External_Rela)))
1697 	    return FALSE;
1698 
1699 	  /* If any dynamic relocs apply to a read-only section,
1700 	     then we need a DT_TEXTREL entry.  */
1701 	  if ((info->flags & DF_TEXTREL) == 0)
1702 	    elf_link_hash_traverse (&htab->elf, readonly_dynrelocs,
1703 				    (PTR) info);
1704 
1705 	  if ((info->flags & DF_TEXTREL) != 0)
1706 	    {
1707 	      if (!add_dynamic_entry (DT_TEXTREL, 0))
1708 		return FALSE;
1709 	    }
1710 	}
1711     }
1712 #undef add_dynamic_entry
1713 
1714   return TRUE;
1715 }
1716 
1717 /* Return the base VMA address which should be subtracted from real addresses
1718    when resolving @dtpoff relocation.
1719    This is PT_TLS segment p_vaddr.  */
1720 
1721 static bfd_vma
dtpoff_base(struct bfd_link_info * info)1722 dtpoff_base (struct bfd_link_info *info)
1723 {
1724   /* If tls_sec is NULL, we should have signalled an error already.  */
1725   if (elf_hash_table (info)->tls_sec == NULL)
1726     return 0;
1727   return elf_hash_table (info)->tls_sec->vma;
1728 }
1729 
1730 /* Return the relocation value for @tpoff relocation
1731    if STT_TLS virtual address is ADDRESS.  */
1732 
1733 static bfd_vma
tpoff(struct bfd_link_info * info,bfd_vma address)1734 tpoff (struct bfd_link_info *info, bfd_vma address)
1735 {
1736   struct elf_link_hash_table *htab = elf_hash_table (info);
1737 
1738   /* If tls_segment is NULL, we should have signalled an error already.  */
1739   if (htab->tls_sec == NULL)
1740     return 0;
1741   return address - htab->tls_size - htab->tls_sec->vma;
1742 }
1743 
1744 /* Relocate an x86_64 ELF section.  */
1745 
1746 static bfd_boolean
elf64_x86_64_relocate_section(bfd * output_bfd,struct bfd_link_info * info,bfd * input_bfd,asection * input_section,bfd_byte * contents,Elf_Internal_Rela * relocs,Elf_Internal_Sym * local_syms,asection ** local_sections)1747 elf64_x86_64_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
1748 			       bfd *input_bfd, asection *input_section,
1749 			       bfd_byte *contents, Elf_Internal_Rela *relocs,
1750 			       Elf_Internal_Sym *local_syms,
1751 			       asection **local_sections)
1752 {
1753   struct elf64_x86_64_link_hash_table *htab;
1754   Elf_Internal_Shdr *symtab_hdr;
1755   struct elf_link_hash_entry **sym_hashes;
1756   bfd_vma *local_got_offsets;
1757   Elf_Internal_Rela *rel;
1758   Elf_Internal_Rela *relend;
1759 
1760   if (info->relocatable)
1761     return TRUE;
1762 
1763   htab = elf64_x86_64_hash_table (info);
1764   symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
1765   sym_hashes = elf_sym_hashes (input_bfd);
1766   local_got_offsets = elf_local_got_offsets (input_bfd);
1767 
1768   rel = relocs;
1769   relend = relocs + input_section->reloc_count;
1770   for (; rel < relend; rel++)
1771     {
1772       unsigned int r_type;
1773       reloc_howto_type *howto;
1774       unsigned long r_symndx;
1775       struct elf_link_hash_entry *h;
1776       Elf_Internal_Sym *sym;
1777       asection *sec;
1778       bfd_vma off;
1779       bfd_vma relocation;
1780       bfd_boolean unresolved_reloc;
1781       bfd_reloc_status_type r;
1782       int tls_type;
1783 
1784       r_type = ELF64_R_TYPE (rel->r_info);
1785       if (r_type == (int) R_X86_64_GNU_VTINHERIT
1786 	  || r_type == (int) R_X86_64_GNU_VTENTRY)
1787 	continue;
1788 
1789       if (r_type >= R_X86_64_max)
1790 	{
1791 	  bfd_set_error (bfd_error_bad_value);
1792 	  return FALSE;
1793 	}
1794 
1795       howto = x86_64_elf_howto_table + r_type;
1796       r_symndx = ELF64_R_SYM (rel->r_info);
1797       h = NULL;
1798       sym = NULL;
1799       sec = NULL;
1800       unresolved_reloc = FALSE;
1801       if (r_symndx < symtab_hdr->sh_info)
1802 	{
1803 	  sym = local_syms + r_symndx;
1804 	  sec = local_sections[r_symndx];
1805 
1806 	  relocation = _bfd_elf_rela_local_sym (output_bfd, sym, &sec, rel);
1807 	}
1808       else
1809 	{
1810 	  bfd_boolean warned;
1811 
1812 	  RELOC_FOR_GLOBAL_SYMBOL (info, input_bfd, input_section, rel,
1813 				   r_symndx, symtab_hdr, sym_hashes,
1814 				   h, sec, relocation,
1815 				   unresolved_reloc, warned);
1816 	}
1817       /* When generating a shared object, the relocations handled here are
1818 	 copied into the output file to be resolved at run time.  */
1819       switch (r_type)
1820 	{
1821 	case R_X86_64_GOT32:
1822 	  /* Relocation is to the entry for this symbol in the global
1823 	     offset table.  */
1824 	case R_X86_64_GOTPCREL:
1825 	  /* Use global offset table as symbol value.  */
1826 	  if (htab->sgot == NULL)
1827 	    abort ();
1828 
1829 	  if (h != NULL)
1830 	    {
1831 	      bfd_boolean dyn;
1832 
1833 	      off = h->got.offset;
1834 	      dyn = htab->elf.dynamic_sections_created;
1835 
1836 	      if (! WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn, info->shared, h)
1837 		  || (info->shared
1838 		      && SYMBOL_REFERENCES_LOCAL (info, h))
1839 		  || (ELF_ST_VISIBILITY (h->other)
1840 		      && h->root.type == bfd_link_hash_undefweak))
1841 		{
1842 		  /* This is actually a static link, or it is a -Bsymbolic
1843 		     link and the symbol is defined locally, or the symbol
1844 		     was forced to be local because of a version file.	We
1845 		     must initialize this entry in the global offset table.
1846 		     Since the offset must always be a multiple of 8, we
1847 		     use the least significant bit to record whether we
1848 		     have initialized it already.
1849 
1850 		     When doing a dynamic link, we create a .rela.got
1851 		     relocation entry to initialize the value.	This is
1852 		     done in the finish_dynamic_symbol routine.	 */
1853 		  if ((off & 1) != 0)
1854 		    off &= ~1;
1855 		  else
1856 		    {
1857 		      bfd_put_64 (output_bfd, relocation,
1858 				  htab->sgot->contents + off);
1859 		      h->got.offset |= 1;
1860 		    }
1861 		}
1862 	      else
1863 		unresolved_reloc = FALSE;
1864 	    }
1865 	  else
1866 	    {
1867 	      if (local_got_offsets == NULL)
1868 		abort ();
1869 
1870 	      off = local_got_offsets[r_symndx];
1871 
1872 	      /* The offset must always be a multiple of 8.  We use
1873 		 the least significant bit to record whether we have
1874 		 already generated the necessary reloc.	 */
1875 	      if ((off & 1) != 0)
1876 		off &= ~1;
1877 	      else
1878 		{
1879 		  bfd_put_64 (output_bfd, relocation,
1880 			      htab->sgot->contents + off);
1881 
1882 		  if (info->shared)
1883 		    {
1884 		      asection *s;
1885 		      Elf_Internal_Rela outrel;
1886 		      bfd_byte *loc;
1887 
1888 		      /* We need to generate a R_X86_64_RELATIVE reloc
1889 			 for the dynamic linker.  */
1890 		      s = htab->srelgot;
1891 		      if (s == NULL)
1892 			abort ();
1893 
1894 		      outrel.r_offset = (htab->sgot->output_section->vma
1895 					 + htab->sgot->output_offset
1896 					 + off);
1897 		      outrel.r_info = ELF64_R_INFO (0, R_X86_64_RELATIVE);
1898 		      outrel.r_addend = relocation;
1899 		      loc = s->contents;
1900 		      loc += s->reloc_count++ * sizeof (Elf64_External_Rela);
1901 		      bfd_elf64_swap_reloca_out (output_bfd, &outrel, loc);
1902 		    }
1903 
1904 		  local_got_offsets[r_symndx] |= 1;
1905 		}
1906 	    }
1907 
1908 	  if (off >= (bfd_vma) -2)
1909 	    abort ();
1910 
1911 	  relocation = htab->sgot->output_offset + off;
1912 	  if (r_type == R_X86_64_GOTPCREL)
1913 	    relocation += htab->sgot->output_section->vma;
1914 
1915 	  break;
1916 
1917 	case R_X86_64_PLT32:
1918 	  /* Relocation is to the entry for this symbol in the
1919 	     procedure linkage table.  */
1920 
1921 	  /* Resolve a PLT32 reloc against a local symbol directly,
1922 	     without using the procedure linkage table.	 */
1923 	  if (h == NULL)
1924 	    break;
1925 
1926 	  if (h->plt.offset == (bfd_vma) -1
1927 	      || htab->splt == NULL)
1928 	    {
1929 	      /* We didn't make a PLT entry for this symbol.  This
1930 		 happens when statically linking PIC code, or when
1931 		 using -Bsymbolic.  */
1932 	      break;
1933 	    }
1934 
1935 	  relocation = (htab->splt->output_section->vma
1936 			+ htab->splt->output_offset
1937 			+ h->plt.offset);
1938 	  unresolved_reloc = FALSE;
1939 	  break;
1940 
1941 	case R_X86_64_PC8:
1942 	case R_X86_64_PC16:
1943 	case R_X86_64_PC32:
1944 	case R_X86_64_8:
1945 	case R_X86_64_16:
1946 	case R_X86_64_32:
1947 	case R_X86_64_64:
1948 	  /* FIXME: The ABI says the linker should make sure the value is
1949 	     the same when it's zeroextended to 64 bit.	 */
1950 
1951 	  /* r_symndx will be zero only for relocs against symbols
1952 	     from removed linkonce sections, or sections discarded by
1953 	     a linker script.  */
1954 	  if (r_symndx == 0
1955 	      || (input_section->flags & SEC_ALLOC) == 0)
1956 	    break;
1957 
1958 	  if ((info->shared
1959 	       && (h == NULL
1960 		   || ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
1961 		   || h->root.type != bfd_link_hash_undefweak)
1962 	       && ((r_type != R_X86_64_PC8
1963 		    && r_type != R_X86_64_PC16
1964 		    && r_type != R_X86_64_PC32)
1965 		   || !SYMBOL_CALLS_LOCAL (info, h)))
1966 	      || (ELIMINATE_COPY_RELOCS
1967 		  && !info->shared
1968 		  && h != NULL
1969 		  && h->dynindx != -1
1970 		  && (h->elf_link_hash_flags & ELF_LINK_NON_GOT_REF) == 0
1971 		  && (((h->elf_link_hash_flags
1972 			& ELF_LINK_HASH_DEF_DYNAMIC) != 0
1973 		       && (h->elf_link_hash_flags
1974 			   & ELF_LINK_HASH_DEF_REGULAR) == 0)
1975 		      || h->root.type == bfd_link_hash_undefweak
1976 		      || h->root.type == bfd_link_hash_undefined)))
1977 	    {
1978 	      Elf_Internal_Rela outrel;
1979 	      bfd_byte *loc;
1980 	      bfd_boolean skip, relocate;
1981 	      asection *sreloc;
1982 
1983 	      /* When generating a shared object, these relocations
1984 		 are copied into the output file to be resolved at run
1985 		 time.	*/
1986 	      skip = FALSE;
1987 	      relocate = FALSE;
1988 
1989 	      outrel.r_offset =
1990 		_bfd_elf_section_offset (output_bfd, info, input_section,
1991 					 rel->r_offset);
1992 	      if (outrel.r_offset == (bfd_vma) -1)
1993 		skip = TRUE;
1994 	      else if (outrel.r_offset == (bfd_vma) -2)
1995 		skip = TRUE, relocate = TRUE;
1996 
1997 	      outrel.r_offset += (input_section->output_section->vma
1998 				  + input_section->output_offset);
1999 
2000 	      if (skip)
2001 		memset (&outrel, 0, sizeof outrel);
2002 
2003 	      /* h->dynindx may be -1 if this symbol was marked to
2004 		 become local.  */
2005 	      else if (h != NULL
2006 		       && h->dynindx != -1
2007 		       && (r_type == R_X86_64_PC8
2008 			   || r_type == R_X86_64_PC16
2009 			   || r_type == R_X86_64_PC32
2010 			   || !info->shared
2011 			   || !info->symbolic
2012 			   || (h->elf_link_hash_flags
2013 			       & ELF_LINK_HASH_DEF_REGULAR) == 0))
2014 		{
2015 		  outrel.r_info = ELF64_R_INFO (h->dynindx, r_type);
2016 		  outrel.r_addend = rel->r_addend;
2017 		}
2018 	      else
2019 		{
2020 		  /* This symbol is local, or marked to become local.  */
2021 		  if (r_type == R_X86_64_64)
2022 		    {
2023 		      relocate = TRUE;
2024 		      outrel.r_info = ELF64_R_INFO (0, R_X86_64_RELATIVE);
2025 		      outrel.r_addend = relocation + rel->r_addend;
2026 		    }
2027 		  else
2028 		    {
2029 		      long sindx;
2030 
2031 		      if (bfd_is_abs_section (sec))
2032 			sindx = 0;
2033 		      else if (sec == NULL || sec->owner == NULL)
2034 			{
2035 			  bfd_set_error (bfd_error_bad_value);
2036 			  return FALSE;
2037 			}
2038 		      else
2039 			{
2040 			  asection *osec;
2041 
2042 			  osec = sec->output_section;
2043 			  sindx = elf_section_data (osec)->dynindx;
2044 			  BFD_ASSERT (sindx > 0);
2045 			}
2046 
2047 		      outrel.r_info = ELF64_R_INFO (sindx, r_type);
2048 		      outrel.r_addend = relocation + rel->r_addend;
2049 		    }
2050 		}
2051 
2052 	      sreloc = elf_section_data (input_section)->sreloc;
2053 	      if (sreloc == NULL)
2054 		abort ();
2055 
2056 	      loc = sreloc->contents;
2057 	      loc += sreloc->reloc_count++ * sizeof (Elf64_External_Rela);
2058 	      bfd_elf64_swap_reloca_out (output_bfd, &outrel, loc);
2059 
2060 	      /* If this reloc is against an external symbol, we do
2061 		 not want to fiddle with the addend.  Otherwise, we
2062 		 need to include the symbol value so that it becomes
2063 		 an addend for the dynamic reloc.  */
2064 	      if (! relocate)
2065 		continue;
2066 	    }
2067 
2068 	  break;
2069 
2070 	case R_X86_64_TLSGD:
2071 	case R_X86_64_GOTTPOFF:
2072 	  r_type = elf64_x86_64_tls_transition (info, r_type, h == NULL);
2073 	  tls_type = GOT_UNKNOWN;
2074 	  if (h == NULL && local_got_offsets)
2075 	    tls_type = elf64_x86_64_local_got_tls_type (input_bfd) [r_symndx];
2076 	  else if (h != NULL)
2077 	    {
2078 	      tls_type = elf64_x86_64_hash_entry (h)->tls_type;
2079 	      if (!info->shared && h->dynindx == -1 && tls_type == GOT_TLS_IE)
2080 		r_type = R_X86_64_TPOFF32;
2081 	    }
2082 	  if (r_type == R_X86_64_TLSGD)
2083 	    {
2084 	      if (tls_type == GOT_TLS_IE)
2085 		r_type = R_X86_64_GOTTPOFF;
2086 	    }
2087 
2088 	  if (r_type == R_X86_64_TPOFF32)
2089 	    {
2090 	      BFD_ASSERT (! unresolved_reloc);
2091 	      if (ELF64_R_TYPE (rel->r_info) == R_X86_64_TLSGD)
2092 		{
2093 		  unsigned int i;
2094 		  static unsigned char tlsgd[8]
2095 		    = { 0x66, 0x48, 0x8d, 0x3d, 0x66, 0x66, 0x48, 0xe8 };
2096 
2097 		  /* GD->LE transition.
2098 		     .byte 0x66; leaq foo@tlsgd(%rip), %rdi
2099 		     .word 0x6666; rex64; call __tls_get_addr@plt
2100 		     Change it into:
2101 		     movq %fs:0, %rax
2102 		     leaq foo@tpoff(%rax), %rax */
2103 		  BFD_ASSERT (rel->r_offset >= 4);
2104 		  for (i = 0; i < 4; i++)
2105 		    BFD_ASSERT (bfd_get_8 (input_bfd,
2106 					   contents + rel->r_offset - 4 + i)
2107 				== tlsgd[i]);
2108 		  BFD_ASSERT (rel->r_offset + 12 <= input_section->_raw_size);
2109 		  for (i = 0; i < 4; i++)
2110 		    BFD_ASSERT (bfd_get_8 (input_bfd,
2111 					   contents + rel->r_offset + 4 + i)
2112 				== tlsgd[i+4]);
2113 		  BFD_ASSERT (rel + 1 < relend);
2114 		  BFD_ASSERT (ELF64_R_TYPE (rel[1].r_info) == R_X86_64_PLT32);
2115 		  memcpy (contents + rel->r_offset - 4,
2116 			  "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0",
2117 			  16);
2118 		  bfd_put_32 (output_bfd, tpoff (info, relocation),
2119 			      contents + rel->r_offset + 8);
2120 		  /* Skip R_X86_64_PLT32.  */
2121 		  rel++;
2122 		  continue;
2123 		}
2124 	      else
2125 		{
2126 		  unsigned int val, type, reg;
2127 
2128 		  /* IE->LE transition:
2129 		     Originally it can be one of:
2130 		     movq foo@gottpoff(%rip), %reg
2131 		     addq foo@gottpoff(%rip), %reg
2132 		     We change it into:
2133 		     movq $foo, %reg
2134 		     leaq foo(%reg), %reg
2135 		     addq $foo, %reg.  */
2136 		  BFD_ASSERT (rel->r_offset >= 3);
2137 		  val = bfd_get_8 (input_bfd, contents + rel->r_offset - 3);
2138 		  BFD_ASSERT (val == 0x48 || val == 0x4c);
2139 		  type = bfd_get_8 (input_bfd, contents + rel->r_offset - 2);
2140 		  BFD_ASSERT (type == 0x8b || type == 0x03);
2141 		  reg = bfd_get_8 (input_bfd, contents + rel->r_offset - 1);
2142 		  BFD_ASSERT ((reg & 0xc7) == 5);
2143 		  reg >>= 3;
2144 		  BFD_ASSERT (rel->r_offset + 4 <= input_section->_raw_size);
2145 		  if (type == 0x8b)
2146 		    {
2147 		      /* movq */
2148 		      if (val == 0x4c)
2149 			bfd_put_8 (output_bfd, 0x49,
2150 				   contents + rel->r_offset - 3);
2151 		      bfd_put_8 (output_bfd, 0xc7,
2152 				 contents + rel->r_offset - 2);
2153 		      bfd_put_8 (output_bfd, 0xc0 | reg,
2154 				 contents + rel->r_offset - 1);
2155 		    }
2156 		  else if (reg == 4)
2157 		    {
2158 		      /* addq -> addq - addressing with %rsp/%r12 is
2159 			 special  */
2160 		      if (val == 0x4c)
2161 			bfd_put_8 (output_bfd, 0x49,
2162 				   contents + rel->r_offset - 3);
2163 		      bfd_put_8 (output_bfd, 0x81,
2164 				 contents + rel->r_offset - 2);
2165 		      bfd_put_8 (output_bfd, 0xc0 | reg,
2166 				 contents + rel->r_offset - 1);
2167 		    }
2168 		  else
2169 		    {
2170 		      /* addq -> leaq */
2171 		      if (val == 0x4c)
2172 			bfd_put_8 (output_bfd, 0x4d,
2173 				   contents + rel->r_offset - 3);
2174 		      bfd_put_8 (output_bfd, 0x8d,
2175 				 contents + rel->r_offset - 2);
2176 		      bfd_put_8 (output_bfd, 0x80 | reg | (reg << 3),
2177 				 contents + rel->r_offset - 1);
2178 		    }
2179 		  bfd_put_32 (output_bfd, tpoff (info, relocation),
2180 			      contents + rel->r_offset);
2181 		  continue;
2182 		}
2183 	    }
2184 
2185 	  if (htab->sgot == NULL)
2186 	    abort ();
2187 
2188 	  if (h != NULL)
2189 	    off = h->got.offset;
2190 	  else
2191 	    {
2192 	      if (local_got_offsets == NULL)
2193 		abort ();
2194 
2195 	      off = local_got_offsets[r_symndx];
2196 	    }
2197 
2198 	  if ((off & 1) != 0)
2199 	    off &= ~1;
2200 	  else
2201 	    {
2202 	      Elf_Internal_Rela outrel;
2203 	      bfd_byte *loc;
2204 	      int dr_type, indx;
2205 
2206 	      if (htab->srelgot == NULL)
2207 		abort ();
2208 
2209 	      outrel.r_offset = (htab->sgot->output_section->vma
2210 				 + htab->sgot->output_offset + off);
2211 
2212 	      indx = h && h->dynindx != -1 ? h->dynindx : 0;
2213 	      if (r_type == R_X86_64_TLSGD)
2214 		dr_type = R_X86_64_DTPMOD64;
2215 	      else
2216 		dr_type = R_X86_64_TPOFF64;
2217 
2218 	      bfd_put_64 (output_bfd, 0, htab->sgot->contents + off);
2219 	      outrel.r_addend = 0;
2220 	      if (dr_type == R_X86_64_TPOFF64 && indx == 0)
2221 		outrel.r_addend = relocation - dtpoff_base (info);
2222 	      outrel.r_info = ELF64_R_INFO (indx, dr_type);
2223 
2224 	      loc = htab->srelgot->contents;
2225 	      loc += htab->srelgot->reloc_count++ * sizeof (Elf64_External_Rela);
2226 	      bfd_elf64_swap_reloca_out (output_bfd, &outrel, loc);
2227 
2228 	      if (r_type == R_X86_64_TLSGD)
2229 		{
2230 		  if (indx == 0)
2231 		    {
2232 		      BFD_ASSERT (! unresolved_reloc);
2233 		      bfd_put_64 (output_bfd,
2234 				  relocation - dtpoff_base (info),
2235 				  htab->sgot->contents + off + GOT_ENTRY_SIZE);
2236 		    }
2237 		  else
2238 		    {
2239 		      bfd_put_64 (output_bfd, 0,
2240 				  htab->sgot->contents + off + GOT_ENTRY_SIZE);
2241 		      outrel.r_info = ELF64_R_INFO (indx,
2242 						    R_X86_64_DTPOFF64);
2243 		      outrel.r_offset += GOT_ENTRY_SIZE;
2244 		      htab->srelgot->reloc_count++;
2245 		      loc += sizeof (Elf64_External_Rela);
2246 		      bfd_elf64_swap_reloca_out (output_bfd, &outrel, loc);
2247 		    }
2248 		}
2249 
2250 	      if (h != NULL)
2251 		h->got.offset |= 1;
2252 	      else
2253 		local_got_offsets[r_symndx] |= 1;
2254 	    }
2255 
2256 	  if (off >= (bfd_vma) -2)
2257 	    abort ();
2258 	  if (r_type == ELF64_R_TYPE (rel->r_info))
2259 	    {
2260 	      relocation = htab->sgot->output_section->vma
2261 			   + htab->sgot->output_offset + off;
2262 	      unresolved_reloc = FALSE;
2263 	    }
2264 	  else
2265 	    {
2266 	      unsigned int i;
2267 	      static unsigned char tlsgd[8]
2268 		= { 0x66, 0x48, 0x8d, 0x3d, 0x66, 0x66, 0x48, 0xe8 };
2269 
2270 	      /* GD->IE transition.
2271 		 .byte 0x66; leaq foo@tlsgd(%rip), %rdi
2272 		 .word 0x6666; rex64; call __tls_get_addr@plt
2273 		 Change it into:
2274 		 movq %fs:0, %rax
2275 		 addq foo@gottpoff(%rip), %rax */
2276 	      BFD_ASSERT (rel->r_offset >= 4);
2277 	      for (i = 0; i < 4; i++)
2278 		BFD_ASSERT (bfd_get_8 (input_bfd,
2279 				       contents + rel->r_offset - 4 + i)
2280 			    == tlsgd[i]);
2281 	      BFD_ASSERT (rel->r_offset + 12 <= input_section->_raw_size);
2282 	      for (i = 0; i < 4; i++)
2283 		BFD_ASSERT (bfd_get_8 (input_bfd,
2284 				       contents + rel->r_offset + 4 + i)
2285 			    == tlsgd[i+4]);
2286 	      BFD_ASSERT (rel + 1 < relend);
2287 	      BFD_ASSERT (ELF64_R_TYPE (rel[1].r_info) == R_X86_64_PLT32);
2288 	      memcpy (contents + rel->r_offset - 4,
2289 		      "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0",
2290 		      16);
2291 
2292 	      relocation = (htab->sgot->output_section->vma
2293 			    + htab->sgot->output_offset + off
2294 			    - rel->r_offset
2295 			    - input_section->output_section->vma
2296 			    - input_section->output_offset
2297 			    - 12);
2298 	      bfd_put_32 (output_bfd, relocation,
2299 			  contents + rel->r_offset + 8);
2300 	      /* Skip R_X86_64_PLT32.  */
2301 	      rel++;
2302 	      continue;
2303 	    }
2304 	  break;
2305 
2306 	case R_X86_64_TLSLD:
2307 	  if (! info->shared)
2308 	    {
2309 	      /* LD->LE transition:
2310 		 Ensure it is:
2311 		 leaq foo@tlsld(%rip), %rdi; call __tls_get_addr@plt.
2312 		 We change it into:
2313 		 .word 0x6666; .byte 0x66; movl %fs:0, %rax.  */
2314 	      BFD_ASSERT (rel->r_offset >= 3);
2315 	      BFD_ASSERT (bfd_get_8 (input_bfd, contents + rel->r_offset - 3)
2316 			  == 0x48);
2317 	      BFD_ASSERT (bfd_get_8 (input_bfd, contents + rel->r_offset - 2)
2318 			  == 0x8d);
2319 	      BFD_ASSERT (bfd_get_8 (input_bfd, contents + rel->r_offset - 1)
2320 			  == 0x3d);
2321 	      BFD_ASSERT (rel->r_offset + 9 <= input_section->_raw_size);
2322 	      BFD_ASSERT (bfd_get_8 (input_bfd, contents + rel->r_offset + 4)
2323 			  == 0xe8);
2324 	      BFD_ASSERT (rel + 1 < relend);
2325 	      BFD_ASSERT (ELF64_R_TYPE (rel[1].r_info) == R_X86_64_PLT32);
2326 	      memcpy (contents + rel->r_offset - 3,
2327 		      "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0", 12);
2328 	      /* Skip R_X86_64_PLT32.  */
2329 	      rel++;
2330 	      continue;
2331 	    }
2332 
2333 	  if (htab->sgot == NULL)
2334 	    abort ();
2335 
2336 	  off = htab->tls_ld_got.offset;
2337 	  if (off & 1)
2338 	    off &= ~1;
2339 	  else
2340 	    {
2341 	      Elf_Internal_Rela outrel;
2342 	      bfd_byte *loc;
2343 
2344 	      if (htab->srelgot == NULL)
2345 		abort ();
2346 
2347 	      outrel.r_offset = (htab->sgot->output_section->vma
2348 				 + htab->sgot->output_offset + off);
2349 
2350 	      bfd_put_64 (output_bfd, 0,
2351 			  htab->sgot->contents + off);
2352 	      bfd_put_64 (output_bfd, 0,
2353 			  htab->sgot->contents + off + GOT_ENTRY_SIZE);
2354 	      outrel.r_info = ELF64_R_INFO (0, R_X86_64_DTPMOD64);
2355 	      outrel.r_addend = 0;
2356 	      loc = htab->srelgot->contents;
2357 	      loc += htab->srelgot->reloc_count++ * sizeof (Elf64_External_Rela);
2358 	      bfd_elf64_swap_reloca_out (output_bfd, &outrel, loc);
2359 	      htab->tls_ld_got.offset |= 1;
2360 	    }
2361 	  relocation = htab->sgot->output_section->vma
2362 		       + htab->sgot->output_offset + off;
2363 	  unresolved_reloc = FALSE;
2364 	  break;
2365 
2366 	case R_X86_64_DTPOFF32:
2367 	  if (info->shared || (input_section->flags & SEC_CODE) == 0)
2368 	    relocation -= dtpoff_base (info);
2369 	  else
2370 	    relocation = tpoff (info, relocation);
2371 	  break;
2372 
2373 	case R_X86_64_TPOFF32:
2374 	  BFD_ASSERT (! info->shared);
2375 	  relocation = tpoff (info, relocation);
2376 	  break;
2377 
2378 	default:
2379 	  break;
2380 	}
2381 
2382       /* Dynamic relocs are not propagated for SEC_DEBUGGING sections
2383 	 because such sections are not SEC_ALLOC and thus ld.so will
2384 	 not process them.  */
2385       if (unresolved_reloc
2386 	  && !((input_section->flags & SEC_DEBUGGING) != 0
2387 	       && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0))
2388 	(*_bfd_error_handler)
2389 	  (_("%s(%s+0x%lx): unresolvable relocation against symbol `%s'"),
2390 	   bfd_archive_filename (input_bfd),
2391 	   bfd_get_section_name (input_bfd, input_section),
2392 	   (long) rel->r_offset,
2393 	   h->root.root.string);
2394 
2395       r = _bfd_final_link_relocate (howto, input_bfd, input_section,
2396 				    contents, rel->r_offset,
2397 				    relocation, rel->r_addend);
2398 
2399       if (r != bfd_reloc_ok)
2400 	{
2401 	  const char *name;
2402 
2403 	  if (h != NULL)
2404 	    name = h->root.root.string;
2405 	  else
2406 	    {
2407 	      name = bfd_elf_string_from_elf_section (input_bfd,
2408 						      symtab_hdr->sh_link,
2409 						      sym->st_name);
2410 	      if (name == NULL)
2411 		return FALSE;
2412 	      if (*name == '\0')
2413 		name = bfd_section_name (input_bfd, sec);
2414 	    }
2415 
2416 	  if (r == bfd_reloc_overflow)
2417 	    {
2418 
2419 	      if (! ((*info->callbacks->reloc_overflow)
2420 		     (info, name, howto->name, (bfd_vma) 0,
2421 		      input_bfd, input_section, rel->r_offset)))
2422 		return FALSE;
2423 	    }
2424 	  else
2425 	    {
2426 	      (*_bfd_error_handler)
2427 		(_("%s(%s+0x%lx): reloc against `%s': error %d"),
2428 		 bfd_archive_filename (input_bfd),
2429 		 bfd_get_section_name (input_bfd, input_section),
2430 		 (long) rel->r_offset, name, (int) r);
2431 	      return FALSE;
2432 	    }
2433 	}
2434     }
2435 
2436   return TRUE;
2437 }
2438 
2439 /* Finish up dynamic symbol handling.  We set the contents of various
2440    dynamic sections here.  */
2441 
2442 static bfd_boolean
elf64_x86_64_finish_dynamic_symbol(bfd * output_bfd,struct bfd_link_info * info,struct elf_link_hash_entry * h,Elf_Internal_Sym * sym)2443 elf64_x86_64_finish_dynamic_symbol (bfd *output_bfd,
2444 				    struct bfd_link_info *info,
2445 				    struct elf_link_hash_entry *h,
2446 				    Elf_Internal_Sym *sym)
2447 {
2448   struct elf64_x86_64_link_hash_table *htab;
2449 
2450   htab = elf64_x86_64_hash_table (info);
2451 
2452   if (h->plt.offset != (bfd_vma) -1)
2453     {
2454       bfd_vma plt_index;
2455       bfd_vma got_offset;
2456       Elf_Internal_Rela rela;
2457       bfd_byte *loc;
2458 
2459       /* This symbol has an entry in the procedure linkage table.  Set
2460 	 it up.	 */
2461       if (h->dynindx == -1
2462 	  || htab->splt == NULL
2463 	  || htab->sgotplt == NULL
2464 	  || htab->srelplt == NULL)
2465 	abort ();
2466 
2467       /* Get the index in the procedure linkage table which
2468 	 corresponds to this symbol.  This is the index of this symbol
2469 	 in all the symbols for which we are making plt entries.  The
2470 	 first entry in the procedure linkage table is reserved.  */
2471       plt_index = h->plt.offset / PLT_ENTRY_SIZE - 1;
2472 
2473       /* Get the offset into the .got table of the entry that
2474 	 corresponds to this function.	Each .got entry is GOT_ENTRY_SIZE
2475 	 bytes. The first three are reserved for the dynamic linker.  */
2476       got_offset = (plt_index + 3) * GOT_ENTRY_SIZE;
2477 
2478       /* Fill in the entry in the procedure linkage table.  */
2479       memcpy (htab->splt->contents + h->plt.offset, elf64_x86_64_plt_entry,
2480 	      PLT_ENTRY_SIZE);
2481 
2482       /* Insert the relocation positions of the plt section.  The magic
2483 	 numbers at the end of the statements are the positions of the
2484 	 relocations in the plt section.  */
2485       /* Put offset for jmp *name@GOTPCREL(%rip), since the
2486 	 instruction uses 6 bytes, subtract this value.  */
2487       bfd_put_32 (output_bfd,
2488 		      (htab->sgotplt->output_section->vma
2489 		       + htab->sgotplt->output_offset
2490 		       + got_offset
2491 		       - htab->splt->output_section->vma
2492 		       - htab->splt->output_offset
2493 		       - h->plt.offset
2494 		       - 6),
2495 		  htab->splt->contents + h->plt.offset + 2);
2496       /* Put relocation index.  */
2497       bfd_put_32 (output_bfd, plt_index,
2498 		  htab->splt->contents + h->plt.offset + 7);
2499       /* Put offset for jmp .PLT0.  */
2500       bfd_put_32 (output_bfd, - (h->plt.offset + PLT_ENTRY_SIZE),
2501 		  htab->splt->contents + h->plt.offset + 12);
2502 
2503       /* Fill in the entry in the global offset table, initially this
2504 	 points to the pushq instruction in the PLT which is at offset 6.  */
2505       bfd_put_64 (output_bfd, (htab->splt->output_section->vma
2506 			       + htab->splt->output_offset
2507 			       + h->plt.offset + 6),
2508 		  htab->sgotplt->contents + got_offset);
2509 
2510       /* Fill in the entry in the .rela.plt section.  */
2511       rela.r_offset = (htab->sgotplt->output_section->vma
2512 		       + htab->sgotplt->output_offset
2513 		       + got_offset);
2514       rela.r_info = ELF64_R_INFO (h->dynindx, R_X86_64_JUMP_SLOT);
2515       rela.r_addend = 0;
2516       loc = htab->srelplt->contents + plt_index * sizeof (Elf64_External_Rela);
2517       bfd_elf64_swap_reloca_out (output_bfd, &rela, loc);
2518 
2519       if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0)
2520 	{
2521 	  /* Mark the symbol as undefined, rather than as defined in
2522 	     the .plt section.  Leave the value alone.  This is a clue
2523 	     for the dynamic linker, to make function pointer
2524 	     comparisons work between an application and shared
2525 	     library.  */
2526 	  sym->st_shndx = SHN_UNDEF;
2527 	}
2528     }
2529 
2530   if (h->got.offset != (bfd_vma) -1
2531       && elf64_x86_64_hash_entry (h)->tls_type != GOT_TLS_GD
2532       && elf64_x86_64_hash_entry (h)->tls_type != GOT_TLS_IE)
2533     {
2534       Elf_Internal_Rela rela;
2535       bfd_byte *loc;
2536 
2537       /* This symbol has an entry in the global offset table.  Set it
2538 	 up.  */
2539       if (htab->sgot == NULL || htab->srelgot == NULL)
2540 	abort ();
2541 
2542       rela.r_offset = (htab->sgot->output_section->vma
2543 		       + htab->sgot->output_offset
2544 		       + (h->got.offset &~ (bfd_vma) 1));
2545 
2546       /* If this is a static link, or it is a -Bsymbolic link and the
2547 	 symbol is defined locally or was forced to be local because
2548 	 of a version file, we just want to emit a RELATIVE reloc.
2549 	 The entry in the global offset table will already have been
2550 	 initialized in the relocate_section function.  */
2551       if (info->shared
2552 	  && SYMBOL_REFERENCES_LOCAL (info, h))
2553 	{
2554 	  BFD_ASSERT((h->got.offset & 1) != 0);
2555 	  rela.r_info = ELF64_R_INFO (0, R_X86_64_RELATIVE);
2556 	  rela.r_addend = (h->root.u.def.value
2557 			   + h->root.u.def.section->output_section->vma
2558 			   + h->root.u.def.section->output_offset);
2559 	}
2560       else
2561 	{
2562 	  BFD_ASSERT((h->got.offset & 1) == 0);
2563 	  bfd_put_64 (output_bfd, (bfd_vma) 0,
2564 		      htab->sgot->contents + h->got.offset);
2565 	  rela.r_info = ELF64_R_INFO (h->dynindx, R_X86_64_GLOB_DAT);
2566 	  rela.r_addend = 0;
2567 	}
2568 
2569       loc = htab->srelgot->contents;
2570       loc += htab->srelgot->reloc_count++ * sizeof (Elf64_External_Rela);
2571       bfd_elf64_swap_reloca_out (output_bfd, &rela, loc);
2572     }
2573 
2574   if ((h->elf_link_hash_flags & ELF_LINK_HASH_NEEDS_COPY) != 0)
2575     {
2576       Elf_Internal_Rela rela;
2577       bfd_byte *loc;
2578 
2579       /* This symbol needs a copy reloc.  Set it up.  */
2580 
2581       if (h->dynindx == -1
2582 	  || (h->root.type != bfd_link_hash_defined
2583 	      && h->root.type != bfd_link_hash_defweak)
2584 	  || htab->srelbss == NULL)
2585 	abort ();
2586 
2587       rela.r_offset = (h->root.u.def.value
2588 		       + h->root.u.def.section->output_section->vma
2589 		       + h->root.u.def.section->output_offset);
2590       rela.r_info = ELF64_R_INFO (h->dynindx, R_X86_64_COPY);
2591       rela.r_addend = 0;
2592       loc = htab->srelbss->contents;
2593       loc += htab->srelbss->reloc_count++ * sizeof (Elf64_External_Rela);
2594       bfd_elf64_swap_reloca_out (output_bfd, &rela, loc);
2595     }
2596 
2597   /* Mark _DYNAMIC and _GLOBAL_OFFSET_TABLE_ as absolute.  */
2598   if (strcmp (h->root.root.string, "_DYNAMIC") == 0
2599       || strcmp (h->root.root.string, "_GLOBAL_OFFSET_TABLE_") == 0)
2600     sym->st_shndx = SHN_ABS;
2601 
2602   return TRUE;
2603 }
2604 
2605 /* Used to decide how to sort relocs in an optimal manner for the
2606    dynamic linker, before writing them out.  */
2607 
2608 static enum elf_reloc_type_class
elf64_x86_64_reloc_type_class(const Elf_Internal_Rela * rela)2609 elf64_x86_64_reloc_type_class (const Elf_Internal_Rela *rela)
2610 {
2611   switch ((int) ELF64_R_TYPE (rela->r_info))
2612     {
2613     case R_X86_64_RELATIVE:
2614       return reloc_class_relative;
2615     case R_X86_64_JUMP_SLOT:
2616       return reloc_class_plt;
2617     case R_X86_64_COPY:
2618       return reloc_class_copy;
2619     default:
2620       return reloc_class_normal;
2621     }
2622 }
2623 
2624 /* Finish up the dynamic sections.  */
2625 
2626 static bfd_boolean
elf64_x86_64_finish_dynamic_sections(bfd * output_bfd,struct bfd_link_info * info)2627 elf64_x86_64_finish_dynamic_sections (bfd *output_bfd, struct bfd_link_info *info)
2628 {
2629   struct elf64_x86_64_link_hash_table *htab;
2630   bfd *dynobj;
2631   asection *sdyn;
2632 
2633   htab = elf64_x86_64_hash_table (info);
2634   dynobj = htab->elf.dynobj;
2635   sdyn = bfd_get_section_by_name (dynobj, ".dynamic");
2636 
2637   if (htab->elf.dynamic_sections_created)
2638     {
2639       Elf64_External_Dyn *dyncon, *dynconend;
2640 
2641       if (sdyn == NULL || htab->sgot == NULL)
2642 	abort ();
2643 
2644       dyncon = (Elf64_External_Dyn *) sdyn->contents;
2645       dynconend = (Elf64_External_Dyn *) (sdyn->contents + sdyn->_raw_size);
2646       for (; dyncon < dynconend; dyncon++)
2647 	{
2648 	  Elf_Internal_Dyn dyn;
2649 	  asection *s;
2650 
2651 	  bfd_elf64_swap_dyn_in (dynobj, dyncon, &dyn);
2652 
2653 	  switch (dyn.d_tag)
2654 	    {
2655 	    default:
2656 	      continue;
2657 
2658 	    case DT_PLTGOT:
2659 	      dyn.d_un.d_ptr = htab->sgot->output_section->vma;
2660 	      break;
2661 
2662 	    case DT_JMPREL:
2663 	      dyn.d_un.d_ptr = htab->srelplt->output_section->vma;
2664 	      break;
2665 
2666 	    case DT_PLTRELSZ:
2667 	      s = htab->srelplt->output_section;
2668 	      if (s->_cooked_size != 0)
2669 		dyn.d_un.d_val = s->_cooked_size;
2670 	      else
2671 		dyn.d_un.d_val = s->_raw_size;
2672 	      break;
2673 
2674 	    case DT_RELASZ:
2675 	      /* The procedure linkage table relocs (DT_JMPREL) should
2676 		 not be included in the overall relocs (DT_RELA).
2677 		 Therefore, we override the DT_RELASZ entry here to
2678 		 make it not include the JMPREL relocs.  Since the
2679 		 linker script arranges for .rela.plt to follow all
2680 		 other relocation sections, we don't have to worry
2681 		 about changing the DT_RELA entry.  */
2682 	      if (htab->srelplt != NULL)
2683 		{
2684 		  s = htab->srelplt->output_section;
2685 		  if (s->_cooked_size != 0)
2686 		    dyn.d_un.d_val -= s->_cooked_size;
2687 		  else
2688 		    dyn.d_un.d_val -= s->_raw_size;
2689 		}
2690 	      break;
2691 	    }
2692 
2693 	  bfd_elf64_swap_dyn_out (output_bfd, &dyn, dyncon);
2694 	}
2695 
2696       /* Fill in the special first entry in the procedure linkage table.  */
2697       if (htab->splt && htab->splt->_raw_size > 0)
2698 	{
2699 	  /* Fill in the first entry in the procedure linkage table.  */
2700 	  memcpy (htab->splt->contents, elf64_x86_64_plt0_entry,
2701 		  PLT_ENTRY_SIZE);
2702 	  /* Add offset for pushq GOT+8(%rip), since the instruction
2703 	     uses 6 bytes subtract this value.  */
2704 	  bfd_put_32 (output_bfd,
2705 		      (htab->sgotplt->output_section->vma
2706 		       + htab->sgotplt->output_offset
2707 		       + 8
2708 		       - htab->splt->output_section->vma
2709 		       - htab->splt->output_offset
2710 		       - 6),
2711 		      htab->splt->contents + 2);
2712 	  /* Add offset for jmp *GOT+16(%rip). The 12 is the offset to
2713 	     the end of the instruction.  */
2714 	  bfd_put_32 (output_bfd,
2715 		      (htab->sgotplt->output_section->vma
2716 		       + htab->sgotplt->output_offset
2717 		       + 16
2718 		       - htab->splt->output_section->vma
2719 		       - htab->splt->output_offset
2720 		       - 12),
2721 		      htab->splt->contents + 8);
2722 
2723 	  elf_section_data (htab->splt->output_section)->this_hdr.sh_entsize =
2724 	    PLT_ENTRY_SIZE;
2725 	}
2726     }
2727 
2728   if (htab->sgotplt)
2729     {
2730       /* Fill in the first three entries in the global offset table.  */
2731       if (htab->sgotplt->_raw_size > 0)
2732 	{
2733 	  /* Set the first entry in the global offset table to the address of
2734 	     the dynamic section.  */
2735 	  if (sdyn == NULL)
2736 	    bfd_put_64 (output_bfd, (bfd_vma) 0, htab->sgotplt->contents);
2737 	  else
2738 	    bfd_put_64 (output_bfd,
2739 			sdyn->output_section->vma + sdyn->output_offset,
2740 			htab->sgotplt->contents);
2741 	  /* Write GOT[1] and GOT[2], needed for the dynamic linker.  */
2742 	  bfd_put_64 (output_bfd, (bfd_vma) 0, htab->sgotplt->contents + GOT_ENTRY_SIZE);
2743 	  bfd_put_64 (output_bfd, (bfd_vma) 0, htab->sgotplt->contents + GOT_ENTRY_SIZE*2);
2744 	}
2745 
2746       elf_section_data (htab->sgotplt->output_section)->this_hdr.sh_entsize =
2747 	GOT_ENTRY_SIZE;
2748     }
2749 
2750   return TRUE;
2751 }
2752 
2753 
2754 #define TARGET_LITTLE_SYM		    bfd_elf64_x86_64_vec
2755 #define TARGET_LITTLE_NAME		    "elf64-x86-64"
2756 #define ELF_ARCH			    bfd_arch_i386
2757 #define ELF_MACHINE_CODE		    EM_X86_64
2758 #define ELF_MAXPAGESIZE			    0x100000
2759 
2760 #define elf_backend_can_gc_sections	    1
2761 #define elf_backend_can_refcount	    1
2762 #define elf_backend_want_got_plt	    1
2763 #define elf_backend_plt_readonly	    1
2764 #define elf_backend_want_plt_sym	    0
2765 #define elf_backend_got_header_size	    (GOT_ENTRY_SIZE*3)
2766 #define elf_backend_rela_normal		    1
2767 
2768 #define elf_info_to_howto		    elf64_x86_64_info_to_howto
2769 
2770 #define bfd_elf64_bfd_link_hash_table_create \
2771   elf64_x86_64_link_hash_table_create
2772 #define bfd_elf64_bfd_reloc_type_lookup	    elf64_x86_64_reloc_type_lookup
2773 
2774 #define elf_backend_adjust_dynamic_symbol   elf64_x86_64_adjust_dynamic_symbol
2775 #define elf_backend_check_relocs	    elf64_x86_64_check_relocs
2776 #define elf_backend_copy_indirect_symbol    elf64_x86_64_copy_indirect_symbol
2777 #define elf_backend_create_dynamic_sections elf64_x86_64_create_dynamic_sections
2778 #define elf_backend_finish_dynamic_sections elf64_x86_64_finish_dynamic_sections
2779 #define elf_backend_finish_dynamic_symbol   elf64_x86_64_finish_dynamic_symbol
2780 #define elf_backend_gc_mark_hook	    elf64_x86_64_gc_mark_hook
2781 #define elf_backend_gc_sweep_hook	    elf64_x86_64_gc_sweep_hook
2782 #define elf_backend_grok_prstatus	    elf64_x86_64_grok_prstatus
2783 #define elf_backend_grok_psinfo		    elf64_x86_64_grok_psinfo
2784 #define elf_backend_reloc_type_class	    elf64_x86_64_reloc_type_class
2785 #define elf_backend_relocate_section	    elf64_x86_64_relocate_section
2786 #define elf_backend_size_dynamic_sections   elf64_x86_64_size_dynamic_sections
2787 #define elf_backend_object_p		    elf64_x86_64_elf_object_p
2788 #define bfd_elf64_mkobject		    elf64_x86_64_mkobject
2789 
2790 #include "elf64-target.h"
2791