1 /* Morpho Technologies MT specific support for 32-bit ELF
2    Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
3    Free Software Foundation, Inc.
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 3 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,
20    MA 02111-1307, USA.  */
21 
22 #include "sysdep.h"
23 #include "bfd.h"
24 #include "libbfd.h"
25 #include "elf-bfd.h"
26 #include "elf/mt.h"
27 
28 /* Prototypes.  */
29 static reloc_howto_type * mt_reloc_type_lookup
30   (bfd *, bfd_reloc_code_real_type);
31 
32 static void mt_info_to_howto_rela
33   (bfd *, arelent *, Elf_Internal_Rela *);
34 
35 static bfd_reloc_status_type mt_elf_relocate_hi16
36   (bfd *, Elf_Internal_Rela *, bfd_byte *, bfd_vma);
37 
38 static bfd_reloc_status_type mt_final_link_relocate
39   (reloc_howto_type *, bfd *, asection *, bfd_byte *,
40    Elf_Internal_Rela *, bfd_vma);
41 
42 static bfd_boolean mt_elf_relocate_section
43   (bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
44    Elf_Internal_Rela *, Elf_Internal_Sym *, asection **);
45 
46 /* Relocation tables.  */
47 static reloc_howto_type mt_elf_howto_table [] =
48 {
49   /* This reloc does nothing.  */
50   HOWTO (R_MT_NONE,           /* type */
51           0,                      /* rightshift */
52           2,                      /* size (0 = byte, 1 = short, 2 = long) */
53           32,                     /* bitsize */
54           FALSE,                  /* pc_relative */
55           0,                      /* bitpos */
56           complain_overflow_dont, /* complain_on_overflow */
57           bfd_elf_generic_reloc,  /* special_function */
58           "R_MT_NONE",          /* name */
59           FALSE,                  /* partial_inplace */
60           0 ,                     /* src_mask */
61           0,                      /* dst_mask */
62           FALSE),                 /* pcrel_offset */
63 
64   /* A 16 bit absolute relocation.  */
65   HOWTO (R_MT_16,             /* type */
66           0,                      /* rightshift */
67           2,                      /* size (0 = byte, 1 = short, 2 = long) */
68           16,                     /* bitsize */
69           FALSE,                  /* pc_relative */
70           0,                      /* bitpos */
71           complain_overflow_dont, /* complain_on_overflow */
72           bfd_elf_generic_reloc,  /* special_function */
73           "R_MT_16",            /* name */
74           FALSE,                  /* partial_inplace */
75           0 ,                     /* src_mask */
76           0xffff,                 /* dst_mask */
77           FALSE),                 /* pcrel_offset */
78 
79   /* A 32 bit absolute relocation.  */
80   HOWTO (R_MT_32,             /* type */
81           0,                      /* rightshift */
82           2,                      /* size (0 = byte, 1 = short, 2 = long) */
83           32,                     /* bitsize */
84           FALSE,                  /* pc_relative */
85           0,                      /* bitpos */
86           complain_overflow_dont, /* complain_on_overflow */
87           bfd_elf_generic_reloc,  /* special_function */
88           "R_MT_32",            /* name */
89           FALSE,                  /* partial_inplace */
90           0 ,                     /* src_mask */
91           0xffffffff,             /* dst_mask */
92           FALSE),                 /* pcrel_offset */
93 
94   /* A 32 bit pc-relative relocation.  */
95   HOWTO (R_MT_32_PCREL,       /* type */
96           0,                      /* rightshift */
97           2,                      /* size (0 = byte, 1 = short, 2 = long) */
98           32,                     /* bitsize */
99           TRUE,                   /* pc_relative */
100           0,                      /* bitpos */
101           complain_overflow_dont, /* complain_on_overflow */
102           bfd_elf_generic_reloc,  /* special_function */
103           "R_MT_32_PCREL",    /* name */
104           FALSE,                  /* partial_inplace */
105           0 ,                     /* src_mask */
106           0xffffffff,             /* dst_mask */
107           TRUE),                  /* pcrel_offset */
108 
109   /* A 16 bit pc-relative relocation.  */
110   HOWTO (R_MT_PC16,           /* type */
111           0,                      /* rightshift */
112           2,                      /* size (0 = byte, 1 = short, 2 = long) */
113           16,                     /* bitsize */
114           TRUE,                   /* pc_relative */
115           0,                      /* bitpos */
116           complain_overflow_signed, /* complain_on_overflow */
117           bfd_elf_generic_reloc,  /* special_function */
118           "R_MT_PC16",          /* name */
119           FALSE,                  /* partial_inplace */
120           0,                      /* src_mask */
121           0xffff,                 /* dst_mask */
122           TRUE),                  /* pcrel_offset */
123 
124   /* high 16 bits of symbol value.  */
125   HOWTO (R_MT_HI16,          /* type */
126          0,                     /* rightshift */
127          2,                     /* size (0 = byte, 1 = short, 2 = long) */
128          16,                    /* bitsize */
129          FALSE,                 /* pc_relative */
130          0,                     /* bitpos */
131          complain_overflow_dont, /* complain_on_overflow */
132          bfd_elf_generic_reloc, /* special_function */
133          "R_MT_HI16",        /* name */
134          FALSE,                  /* partial_inplace */
135          0xffff0000,            /* src_mask */
136          0xffff0000,            /* dst_mask */
137          FALSE),                /* pcrel_offset */
138 
139   /* Low 16 bits of symbol value.  */
140   HOWTO (R_MT_LO16,          /* type */
141          0,                     /* rightshift */
142          2,                     /* size (0 = byte, 1 = short, 2 = long) */
143          16,                    /* bitsize */
144          FALSE,                 /* pc_relative */
145          0,                     /* bitpos */
146          complain_overflow_dont, /* complain_on_overflow */
147          bfd_elf_generic_reloc, /* special_function */
148          "R_MT_LO16",        /* name */
149          FALSE,                  /* partial_inplace */
150          0xffff,                /* src_mask */
151          0xffff,                /* dst_mask */
152          FALSE),                /* pcrel_offset */
153 };
154 
155 /* Map BFD reloc types to MT ELF reloc types.  */
156 
157 static reloc_howto_type *
158 mt_reloc_type_lookup
159     (bfd *                    abfd ATTRIBUTE_UNUSED,
160      bfd_reloc_code_real_type code)
161 {
162   /* Note that the mt_elf_howto_table is indxed by the R_
163      constants.  Thus, the order that the howto records appear in the
164      table *must* match the order of the relocation types defined in
165      include/elf/mt.h.  */
166 
167   switch (code)
168     {
169     case BFD_RELOC_NONE:
170       return &mt_elf_howto_table[ (int) R_MT_NONE];
171     case BFD_RELOC_16:
172       return &mt_elf_howto_table[ (int) R_MT_16];
173     case BFD_RELOC_32:
174       return &mt_elf_howto_table[ (int) R_MT_32];
175     case BFD_RELOC_32_PCREL:
176       return &mt_elf_howto_table[ (int) R_MT_32_PCREL];
177     case BFD_RELOC_16_PCREL:
178       return &mt_elf_howto_table[ (int) R_MT_PC16];
179     case BFD_RELOC_HI16:
180       return &mt_elf_howto_table[ (int) R_MT_HI16];
181     case BFD_RELOC_LO16:
182       return &mt_elf_howto_table[ (int) R_MT_LO16];
183 
184     default:
185       /* Pacify gcc -Wall.  */
186       return NULL;
187     }
188   return NULL;
189 }
190 
191 static reloc_howto_type *
192 mt_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED,
193 		      const char *r_name)
194 {
195   unsigned int i;
196 
197   for (i = 0;
198        i < sizeof (mt_elf_howto_table) / sizeof (mt_elf_howto_table[0]);
199        i++)
200     if (mt_elf_howto_table[i].name != NULL
201 	&& strcasecmp (mt_elf_howto_table[i].name, r_name) == 0)
202       return &mt_elf_howto_table[i];
203 
204   return NULL;
205 }
206 
207 bfd_reloc_status_type
208 mt_elf_relocate_hi16
209     (bfd *               input_bfd,
210      Elf_Internal_Rela * relhi,
211      bfd_byte *          contents,
212      bfd_vma             value)
213 {
214   bfd_vma insn;
215 
216   insn = bfd_get_32 (input_bfd, contents + relhi->r_offset);
217 
218   value += relhi->r_addend;
219   value >>= 16;
220   insn = ((insn & ~0xFFFF) | value);
221 
222   bfd_put_32 (input_bfd, insn, contents + relhi->r_offset);
223   return bfd_reloc_ok;
224 }
225 
226 /* XXX: The following code is the result of a cut&paste.  This unfortunate
227    practice is very widespread in the various target back-end files.  */
228 
229 /* Set the howto pointer for a MT ELF reloc.  */
230 
231 static void
232 mt_info_to_howto_rela
233     (bfd *               abfd ATTRIBUTE_UNUSED,
234      arelent *           cache_ptr,
235      Elf_Internal_Rela * dst)
236 {
237   unsigned int r_type;
238 
239   r_type = ELF32_R_TYPE (dst->r_info);
240   cache_ptr->howto = & mt_elf_howto_table [r_type];
241 }
242 
243 /* Perform a single relocation.  By default we use the standard BFD
244    routines.  */
245 
246 static bfd_reloc_status_type
247 mt_final_link_relocate
248     (reloc_howto_type *  howto,
249      bfd *               input_bfd,
250      asection *          input_section,
251      bfd_byte *          contents,
252      Elf_Internal_Rela * rel,
253      bfd_vma             relocation)
254 {
255   return _bfd_final_link_relocate (howto, input_bfd, input_section,
256 				   contents, rel->r_offset,
257 				   relocation, rel->r_addend);
258 }
259 
260 /* Relocate a MT ELF section.
261    There is some attempt to make this function usable for many architectures,
262    both USE_REL and USE_RELA ['twould be nice if such a critter existed],
263    if only to serve as a learning tool.
264 
265    The RELOCATE_SECTION function is called by the new ELF backend linker
266    to handle the relocations for a section.
267 
268    The relocs are always passed as Rela structures; if the section
269    actually uses Rel structures, the r_addend field will always be
270    zero.
271 
272    This function is responsible for adjusting the section contents as
273    necessary, and (if using Rela relocs and generating a relocatable
274    output file) adjusting the reloc addend as necessary.
275 
276    This function does not have to worry about setting the reloc
277    address or the reloc symbol index.
278 
279    LOCAL_SYMS is a pointer to the swapped in local symbols.
280 
281    LOCAL_SECTIONS is an array giving the section in the input file
282    corresponding to the st_shndx field of each local symbol.
283 
284    The global hash table entry for the global symbols can be found
285    via elf_sym_hashes (input_bfd).
286 
287    When generating relocatable output, this function must handle
288    STB_LOCAL/STT_SECTION symbols specially.  The output symbol is
289    going to be the section symbol corresponding to the output
290    section, which means that the addend must be adjusted
291    accordingly.  */
292 
293 static bfd_boolean
294 mt_elf_relocate_section
295     (bfd *                   output_bfd ATTRIBUTE_UNUSED,
296      struct bfd_link_info *  info,
297      bfd *                   input_bfd,
298      asection *              input_section,
299      bfd_byte *              contents,
300      Elf_Internal_Rela *     relocs,
301      Elf_Internal_Sym *      local_syms,
302      asection **             local_sections)
303 {
304   Elf_Internal_Shdr *           symtab_hdr;
305   struct elf_link_hash_entry ** sym_hashes;
306   Elf_Internal_Rela *           rel;
307   Elf_Internal_Rela *           relend;
308 
309   symtab_hdr = & elf_tdata (input_bfd)->symtab_hdr;
310   sym_hashes = elf_sym_hashes (input_bfd);
311   relend     = relocs + input_section->reloc_count;
312 
313   for (rel = relocs; rel < relend; rel ++)
314     {
315       reloc_howto_type *           howto;
316       unsigned long                r_symndx;
317       Elf_Internal_Sym *           sym;
318       asection *                   sec;
319       struct elf_link_hash_entry * h;
320       bfd_vma                      relocation;
321       bfd_reloc_status_type        r;
322       const char *                 name = NULL;
323       int                          r_type;
324 
325       r_type = ELF32_R_TYPE (rel->r_info);
326 
327       r_symndx = ELF32_R_SYM (rel->r_info);
328 
329       howto  = mt_elf_howto_table + ELF32_R_TYPE (rel->r_info);
330       h      = NULL;
331       sym    = NULL;
332       sec    = NULL;
333 
334       if (r_symndx < symtab_hdr->sh_info)
335 	{
336 	  sym = local_syms + r_symndx;
337 	  sec = local_sections [r_symndx];
338 	  relocation = _bfd_elf_rela_local_sym (output_bfd, sym, &sec, rel);
339 
340 	  name = bfd_elf_string_from_elf_section
341 	    (input_bfd, symtab_hdr->sh_link, sym->st_name);
342 	  name = (name == NULL) ? bfd_section_name (input_bfd, sec) : name;
343 	}
344       else
345 	{
346 	  bfd_boolean unresolved_reloc;
347 	  bfd_boolean warned;
348 
349 	  RELOC_FOR_GLOBAL_SYMBOL (info, input_bfd, input_section, rel,
350 				   r_symndx, symtab_hdr, sym_hashes,
351 				   h, sec, relocation,
352 				   unresolved_reloc, warned);
353 
354 	  name = h->root.root.string;
355 	}
356 
357       if (sec != NULL && elf_discarded_section (sec))
358 	{
359 	  /* For relocs against symbols from removed linkonce sections,
360 	     or sections discarded by a linker script, we just want the
361 	     section contents zeroed.  Avoid any special processing.  */
362 	  _bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
363 	  rel->r_info = 0;
364 	  rel->r_addend = 0;
365 	  continue;
366 	}
367 
368       if (info->relocatable)
369 	continue;
370 
371       /* Finally, the sole MT-specific part.  */
372       switch (r_type)
373         {
374         case R_MT_HI16:
375           r = mt_elf_relocate_hi16 (input_bfd, rel, contents, relocation);
376           break;
377 	default:
378           r = mt_final_link_relocate (howto, input_bfd, input_section,
379 		        		  contents, rel, relocation);
380           break;
381         }
382 
383 
384       if (r != bfd_reloc_ok)
385 	{
386 	  const char * msg = (const char *) NULL;
387 
388 	  switch (r)
389 	    {
390 	    case bfd_reloc_overflow:
391 	      r = info->callbacks->reloc_overflow
392 		(info, (h ? &h->root : NULL), name, howto->name, (bfd_vma) 0,
393 		 input_bfd, input_section, rel->r_offset);
394 	      break;
395 
396 	    case bfd_reloc_undefined:
397 	      r = info->callbacks->undefined_symbol
398 		(info, name, input_bfd, input_section, rel->r_offset, TRUE);
399 	      break;
400 
401 	    case bfd_reloc_outofrange:
402 	      msg = _("internal error: out of range error");
403 	      break;
404 
405 	    case bfd_reloc_dangerous:
406 	      msg = _("internal error: dangerous relocation");
407 	      break;
408 
409 	    default:
410 	      msg = _("internal error: unknown error");
411 	      break;
412 	    }
413 
414 	  if (msg)
415 	    r = info->callbacks->warning
416 	      (info, msg, name, input_bfd, input_section, rel->r_offset);
417 
418 	  if (! r)
419 	    return FALSE;
420 	}
421     }
422 
423   return TRUE;
424 }
425 
426 /* Look through the relocs for a section during the first phase.
427    Since we don't do .gots or .plts, we just need to consider the
428    virtual table relocs for gc.  */
429 
430 static bfd_boolean
431 mt_elf_check_relocs
432     (bfd *                     abfd,
433      struct bfd_link_info *    info,
434      asection *                sec,
435      const Elf_Internal_Rela * relocs)
436 {
437   Elf_Internal_Shdr *           symtab_hdr;
438   struct elf_link_hash_entry ** sym_hashes;
439   const Elf_Internal_Rela *     rel;
440   const Elf_Internal_Rela *     rel_end;
441 
442   if (info->relocatable)
443     return TRUE;
444 
445   symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
446   sym_hashes = elf_sym_hashes (abfd);
447 
448   rel_end = relocs + sec->reloc_count;
449   for (rel = relocs; rel < rel_end; rel++)
450     {
451       struct elf_link_hash_entry *h;
452       unsigned long r_symndx;
453 
454       r_symndx = ELF32_R_SYM (rel->r_info);
455       if (r_symndx < symtab_hdr->sh_info)
456         h = NULL;
457       else
458 	{
459 	  h = sym_hashes[r_symndx - symtab_hdr->sh_info];
460 	  while (h->root.type == bfd_link_hash_indirect
461 		 || h->root.type == bfd_link_hash_warning)
462 	    h = (struct elf_link_hash_entry *) h->root.u.i.link;
463 	}
464     }
465 
466   return TRUE;
467 }
468 
469 /* Return the MACH for an e_flags value.  */
470 
471 static int
472 elf32_mt_machine (bfd *abfd)
473 {
474   switch (elf_elfheader (abfd)->e_flags & EF_MT_CPU_MASK)
475     {
476     case EF_MT_CPU_MRISC:	return bfd_mach_ms1;
477     case EF_MT_CPU_MRISC2:	return bfd_mach_mrisc2;
478     case EF_MT_CPU_MS2:		return bfd_mach_ms2;
479     }
480 
481   return bfd_mach_ms1;
482 }
483 
484 static bfd_boolean
485 mt_elf_object_p (bfd * abfd)
486 {
487   bfd_default_set_arch_mach (abfd, bfd_arch_mt, elf32_mt_machine (abfd));
488 
489   return TRUE;
490 }
491 
492 /* Function to set the ELF flag bits.  */
493 
494 static bfd_boolean
495 mt_elf_set_private_flags (bfd *    abfd,
496 			   flagword flags)
497 {
498   elf_elfheader (abfd)->e_flags = flags;
499   elf_flags_init (abfd) = TRUE;
500   return TRUE;
501 }
502 
503 static bfd_boolean
504 mt_elf_copy_private_bfd_data (bfd * ibfd, bfd * obfd)
505 {
506   if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour
507       || bfd_get_flavour (obfd) != bfd_target_elf_flavour)
508     return TRUE;
509 
510   BFD_ASSERT (!elf_flags_init (obfd)
511 	      || elf_elfheader (obfd)->e_flags == elf_elfheader (ibfd)->e_flags);
512 
513   elf_elfheader (obfd)->e_flags = elf_elfheader (ibfd)->e_flags;
514   elf_flags_init (obfd) = TRUE;
515 
516   /* Copy object attributes.  */
517   _bfd_elf_copy_obj_attributes (ibfd, obfd);
518 
519   return TRUE;
520 }
521 
522 /* Merge backend specific data from an object file to the output
523    object file when linking.  */
524 
525 static bfd_boolean
526 mt_elf_merge_private_bfd_data (bfd * ibfd, bfd * obfd)
527 {
528   flagword     old_flags, new_flags;
529   bfd_boolean  ok = TRUE;
530 
531   /* Check if we have the same endianess.  */
532   if (_bfd_generic_verify_endian_match (ibfd, obfd) == FALSE)
533     return FALSE;
534 
535   /* If they're not both mt, then merging is meaningless, so just
536      don't do it.  */
537   if (strcmp (ibfd->arch_info->arch_name, "mt") != 0)
538     return TRUE;
539   if (strcmp (obfd->arch_info->arch_name, "mt") != 0)
540     return TRUE;
541 
542   new_flags = elf_elfheader (ibfd)->e_flags;
543   old_flags = elf_elfheader (obfd)->e_flags;
544 
545 #ifdef DEBUG
546   _bfd_error_handler ("%B: old_flags = 0x%.8lx, new_flags = 0x%.8lx, init = %s",
547 		      ibfd, old_flags, new_flags, elf_flags_init (obfd) ? "yes" : "no");
548 #endif
549 
550   if (!elf_flags_init (obfd))
551     {
552       old_flags = new_flags;
553       elf_flags_init (obfd) = TRUE;
554     }
555   else if ((new_flags & EF_MT_CPU_MASK) != (old_flags & EF_MT_CPU_MASK))
556     {
557       /* CPU has changed.  This is invalid, because MRISC, MRISC2 and
558 	 MS2 are not subsets of each other.   */
559       ok = FALSE;
560     }
561 
562   if (ok)
563     {
564       obfd->arch_info = ibfd->arch_info;
565       elf_elfheader (obfd)->e_flags = old_flags;
566     }
567 
568   return ok;
569 }
570 
571 static bfd_boolean
572 mt_elf_print_private_bfd_data (bfd * abfd, void * ptr)
573 {
574   FILE *   file = (FILE *) ptr;
575   flagword flags;
576 
577   BFD_ASSERT (abfd != NULL && ptr != NULL);
578 
579   /* Print normal ELF private data.  */
580   _bfd_elf_print_private_bfd_data (abfd, ptr);
581 
582   flags = elf_elfheader (abfd)->e_flags;
583   fprintf (file, _("private flags = 0x%lx:"), (unsigned long) flags);
584 
585   switch (flags & EF_MT_CPU_MASK)
586     {
587     default:
588     case EF_MT_CPU_MRISC:   fprintf (file, " ms1-16-002");	break;
589     case EF_MT_CPU_MRISC2:  fprintf (file, " ms1-16-003");	break;
590     case EF_MT_CPU_MS2:     fprintf (file, " ms2");	break;
591     }
592 
593   fputc ('\n', file);
594 
595   return TRUE;
596 }
597 
598 
599 #define TARGET_BIG_SYM	 bfd_elf32_mt_vec
600 #define TARGET_BIG_NAME  "elf32-mt"
601 
602 #define ELF_ARCH	 bfd_arch_mt
603 #define ELF_MACHINE_CODE EM_MT
604 #define ELF_MAXPAGESIZE  1 /* No pages on the MT.  */
605 
606 #define elf_info_to_howto_rel			NULL
607 #define elf_info_to_howto			mt_info_to_howto_rela
608 
609 #define elf_backend_relocate_section		mt_elf_relocate_section
610 
611 #define bfd_elf32_bfd_reloc_type_lookup	        mt_reloc_type_lookup
612 #define bfd_elf32_bfd_reloc_name_lookup   mt_reloc_name_lookup
613 
614 #define elf_backend_check_relocs                mt_elf_check_relocs
615 #define elf_backend_object_p		        mt_elf_object_p
616 #define elf_backend_rela_normal			1
617 
618 #define elf_backend_can_gc_sections		1
619 
620 #define bfd_elf32_bfd_set_private_flags		mt_elf_set_private_flags
621 #define bfd_elf32_bfd_copy_private_bfd_data	mt_elf_copy_private_bfd_data
622 #define bfd_elf32_bfd_merge_private_bfd_data	mt_elf_merge_private_bfd_data
623 #define bfd_elf32_bfd_print_private_bfd_data	mt_elf_print_private_bfd_data
624 
625 #include "elf32-target.h"
626