bfd/aout-cris.c

   1 /* BFD backend for CRIS a.out binaries.
   2    Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2009
   3    Free Software Foundation, Inc.
   4    Contributed by Axis Communications AB.
   5    Written by Hans-Peter Nilsson.
   6
   7    This file is part of BFD, the Binary File Descriptor library.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  22    MA 02110-1301, USA.  */
  23
  24 /* See info in the file PORTING for documentation of these macros and
  25    functions.  Beware; some of the information there is outdated.  */
  26
  27 #define N_HEADER_IN_TEXT(x) 0
  28 #define N_TXTOFF(x)         32
  29 #define ENTRY_CAN_BE_ZERO
  30 #define TEXT_START_ADDR     0
  31
  32 /* Without reading symbols to get the text start symbol, there is no way
  33    to know where the text segment starts in an a.out file.  Defaulting to
  34    anything as constant as TEXT_START_ADDR is bad.  But we can guess from
  35    the entry point, which is usually within the first 64k of the text
  36    segment.  We also assume here that the text segment is 64k-aligned.
  37    FIXME: It is also wrong to assume that data and bss follow immediately
  38    after text, but with those, we don't have any choice besides reading
  39    symbol info, and luckily there's no pressing need for correctness for
  40    those vma:s at this time.  */
  41 #define N_TXTADDR(x) ((x).a_entry & ~(bfd_vma) 0xffff)
  42
  43 /* If you change this to 4, you can not link to an address N*4+2.  */
  44 #define SEGMENT_SIZE 2
  45
  46 /* For some reason, if the a.out file has Z_MAGIC, then
  47    adata(abfd).exec_bytes_size is not used, but rather
  48    adata(abfd).zmagic_disk_block_size, even though the exec_header is
  49    *not* included in the text segment.  A simple workaround is to
  50    #define ZMAGIC_DISK_BLOCK_SIZE, which is used if defined; otherwise
  51    TARGET_PAGE_SIZE is used.  */
  52 #define ZMAGIC_DISK_BLOCK_SIZE     N_TXTOFF (0)
  53
  54 /* It seems odd at first to set a page-size this low, but gives greater
  55    freedom in where things can be linked.  The drawback is that you have
  56    to set alignment and padding in linker scripts.  */
  57 #define TARGET_PAGE_SIZE SEGMENT_SIZE
  58 #define TARGETNAME "a.out-cris"
  59
  60 /* The definition here seems not used; just provided as a convention.  */
  61 #define DEFAULT_ARCH bfd_arch_cris
  62
  63 /* Do not "beautify" the CONCAT* macro args.  Traditional C will not
  64    remove whitespace added here, and thus will fail to concatenate
  65    the tokens.  */
  66 #define MY(OP) CONCAT2 (cris_aout_,OP)
  67 #define NAME(x, y) CONCAT3 (cris_aout,_32_,y)
  68
  69 #include "bfd.h"
  70
  71 /* Version 1 of the header.  */
  72 #define MY_exec_hdr_flags 1
  73
  74 #define MY_write_object_contents MY (write_object_contents)
  75 static bfd_boolean MY (write_object_contents) (bfd *);
  76
  77 /* Forward this, so we can use a pointer to it in PARAMS.  */
  78 struct reloc_ext_external;
  79
  80 #define MY_swap_ext_reloc_out MY (swap_ext_reloc_out)
  81 static void MY (swap_ext_reloc_out) (bfd *, arelent *, struct reloc_ext_external *);
  82
  83 #define MY_swap_ext_reloc_in MY (swap_ext_reloc_in)
  84 static void MY (swap_ext_reloc_in) (bfd *, struct reloc_ext_external *,
  85                                     arelent *, asymbol **, bfd_size_type);
  86
  87 #define MY_set_sizes MY (set_sizes)
  88 static bfd_boolean MY (set_sizes) (bfd *);
  89
  90 /* To set back reloc_size to ext, we make MY (set_sizes) be called
  91    through this construct.  Note that MY_set_arch_mach is only called
  92    through SET_ARCH_MACH.  The default bfd_default_set_arch_mach will
  93    not call set_sizes.  */
  94
  95 #define MY_set_arch_mach NAME (aout, set_arch_mach)
  96 #define SET_ARCH_MACH(BFD, EXEC) \
  97  MY_set_arch_mach (BFD, DEFAULT_ARCH, N_MACHTYPE (EXEC))
  98
  99 /* These macros describe the binary layout of the reloc information we
 100    use in a file.  */
 101 #define RELOC_EXT_BITS_EXTERN_LITTLE  0x80
 102 #define RELOC_EXT_BITS_TYPE_LITTLE    3
 103 #define RELOC_EXT_BITS_TYPE_SH_LITTLE 0
 104
 105 #ifndef MY_get_section_contents
 106 #define MY_get_section_contents aout_32_get_section_contents
 107 #endif
 108
 109 #define MACHTYPE_OK(mtype) ((mtype) == M_CRIS)
 110
 111 /* Include generic functions (some are overridden above).  */
 112 #include "aout32.c"
 113 #include "aout-target.h"
 114
 115 /* We need our own version to set header flags.  */
 116
 117 static bfd_boolean
 118 MY (write_object_contents) (bfd *abfd)
 119 {
 120   struct external_exec exec_bytes;
 121   struct internal_exec *execp = exec_hdr (abfd);
 122
 123   /* We set the reloc type to RELOC_EXT_SIZE, although setting it at all
 124      seems unnecessary when inspecting as and ld behavior (not an
 125      exhaustive inspection).  The default write_object_contents
 126      definition sets RELOC_EXT_SIZE, so we follow suite and set it too.  */
 127   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 128
 129   /* Setting N_SET_MACHTYPE and using N_SET_FLAGS is not performed by
 130      the default definition.  */
 131   if (bfd_get_arch (abfd) == bfd_arch_cris)
 132     N_SET_MACHTYPE (*execp, M_CRIS);
 133
 134   N_SET_FLAGS (*execp, aout_backend_info (abfd)->exec_hdr_flags);
 135
 136   WRITE_HEADERS (abfd, execp);
 137
 138   return TRUE;
 139 }
 140
 141 /* We need our own for these reasons:
 142    - Assert that a normal 8, 16 or 32 reloc is output.
 143    - Fix what seems to be a weak-bug (perhaps there for valid reasons).  */
 144
 145 static void
 146 MY (swap_ext_reloc_out) (bfd *abfd,
 147                          arelent *g,
 148                          struct reloc_ext_external *natptr)
 149 {
 150   int r_index;
 151   int r_extern;
 152   unsigned int r_type;
 153   bfd_vma r_addend;
 154   asymbol *sym = *(g->sym_ptr_ptr);
 155   asection *output_section = sym->section->output_section;
 156
 157   PUT_WORD (abfd, g->address, natptr->r_address);
 158
 159   r_type = (unsigned int) g->howto->type;
 160
 161   r_addend = g->addend;
 162   if ((sym->flags & BSF_SECTION_SYM) != 0)
 163     r_addend += (*(g->sym_ptr_ptr))->section->output_section->vma;
 164
 165   /* If this relocation is relative to a symbol then set the
 166      r_index to the symbols index, and the r_extern bit.
 167
 168      Absolute symbols can come in in two ways, either as an offset
 169      from the abs section, or as a symbol which has an abs value.
 170      check for that here.  */
 171
 172   if (bfd_is_abs_section (bfd_get_section (sym)))
 173     {
 174       r_extern = 0;
 175       r_index = N_ABS;
 176     }
 177   else if ((sym->flags & BSF_SECTION_SYM) == 0)
 178     {
 179       if (bfd_is_und_section (bfd_get_section (sym))
 180           /* Remember to check for weak symbols; they count as global.  */
 181           || (sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
 182         r_extern = 1;
 183       else
 184         r_extern = 0;
 185       r_index = (*(g->sym_ptr_ptr))->KEEPIT;
 186     }
 187   else
 188     {
 189       /* Just an ordinary section.  */
 190       r_extern = 0;
 191       r_index = output_section->target_index;
 192     }
 193
 194   /* The relocation type is the same as the canonical ones, but only
 195      the first 3 are used: RELOC_8, RELOC_16, RELOC_32.
 196      We may change this later, but assert this for the moment.  */
 197   if (r_type > 2)
 198     {
 199       (*_bfd_error_handler) (_("%s: Invalid relocation type exported: %d"),
 200                              bfd_get_filename (abfd), r_type);
 201
 202       bfd_set_error (bfd_error_wrong_format);
 203     }
 204
 205   /* Now the fun stuff.  */
 206   natptr->r_index[2] = r_index >> 16;
 207   natptr->r_index[1] = r_index >> 8;
 208   natptr->r_index[0] = r_index;
 209   natptr->r_type[0] =
 210      (r_extern ? RELOC_EXT_BITS_EXTERN_LITTLE : 0)
 211       | (r_type << RELOC_EXT_BITS_TYPE_SH_LITTLE);
 212
 213   PUT_WORD (abfd, r_addend, natptr->r_addend);
 214 }
 215
 216 /* We need our own to assert that a normal 8, 16 or 32 reloc is input.  */
 217
 218 static void
 219 MY (swap_ext_reloc_in) (bfd *abfd,
 220                         struct reloc_ext_external *bytes,
 221                         arelent *cache_ptr,
 222                         asymbol **symbols,
 223                         bfd_size_type symcount)
 224 {
 225   unsigned int r_index;
 226   int r_extern;
 227   unsigned int r_type;
 228   struct aoutdata *su = &(abfd->tdata.aout_data->a);
 229
 230   cache_ptr->address = (GET_SWORD (abfd, bytes->r_address));
 231
 232   /* Now the fun stuff.  */
 233   r_index =  (bytes->r_index[2] << 16)
 234     | (bytes->r_index[1] << 8)
 235     |  bytes->r_index[0];
 236   r_extern = (0 != (bytes->r_type[0] & RELOC_EXT_BITS_EXTERN_LITTLE));
 237   r_type = ((bytes->r_type[0]) >> RELOC_EXT_BITS_TYPE_SH_LITTLE)
 238     & RELOC_EXT_BITS_TYPE_LITTLE;
 239
 240   if (r_type > 2)
 241     {
 242       (*_bfd_error_handler) (_("%B: Invalid relocation type imported: %d"),
 243                              abfd, r_type);
 244
 245       bfd_set_error (bfd_error_wrong_format);
 246     }
 247
 248   cache_ptr->howto =  howto_table_ext + r_type;
 249
 250   if (r_extern && r_index > symcount)
 251     {
 252       (*_bfd_error_handler)
 253         (_("%B: Bad relocation record imported: %d"), abfd, r_index);
 254
 255       bfd_set_error (bfd_error_wrong_format);
 256
 257       /* We continue, so we can catch further errors.  */
 258       r_extern = 0;
 259       r_index = N_ABS;
 260     }
 261
 262   /* Magically uses r_extern, symbols etc.  Ugly, but it's what's in the
 263      default.  */
 264   MOVE_ADDRESS (GET_SWORD (abfd, bytes->r_addend));
 265 }
 266
 267 /* We use the same as the default, except that we also set
 268    "obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;", to avoid changing
 269    NAME (aout, set_arch_mach) in aoutx.  */
 270
 271 static bfd_boolean
 272 MY (set_sizes) (bfd *abfd)
 273 {
 274   /* Just as the default in aout-target.h (with some #ifdefs folded)...  */
 275
 276   adata (abfd).page_size = TARGET_PAGE_SIZE;
 277   adata (abfd).segment_size = SEGMENT_SIZE;
 278   adata (abfd).zmagic_disk_block_size = ZMAGIC_DISK_BLOCK_SIZE;
 279   adata (abfd).exec_bytes_size = EXEC_BYTES_SIZE;
 280
 281   /* ... except for that we have the extended reloc.  The alternative
 282      would be to add a check on bfd_arch_cris in NAME (aout,
 283      set_arch_mach) in aoutx.h, but I don't want to do that since
 284      target-specific things should not be added there.  */
 285
 286   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 287
 288   return TRUE;
 289 }