bfd/aout-cris.c

   1 /* BFD backend for CRIS a.out binaries.
   2    Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2007
   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  Beware; some of the information there is outdated.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 /* N_SHARED_LIB gets this reasonable default as of 1999-07-12, but we
  61    have to work with 2.9.1.  Note that N_SHARED_LIB is used in a
  62    SUN-specific context, not applicable to CRIS.  */
  63 #define N_SHARED_LIB(x) 0
  64
  65 /* The definition here seems not used; just provided as a convention.  */
  66 #define DEFAULT_ARCH bfd_arch_cris
  67
  68 /* Do not "beautify" the CONCAT* macro args.  Traditional C will not
  69    remove whitespace added here, and thus will fail to concatenate
  70    the tokens.  */
  71 #define MY(OP) CONCAT2 (cris_aout_,OP)
  72 #define NAME(x, y) CONCAT3 (cris_aout,_32_,y)
  73
  74 #include "bfd.h"
  75
  76 /* Version 1 of the header.  */
  77 #define MY_exec_hdr_flags 1
  78
  79 #define MY_write_object_contents MY (write_object_contents)
  80 static bfd_boolean MY (write_object_contents) (bfd *);
  81
  82 /* Forward this, so we can use a pointer to it in PARAMS.  */
  83 struct reloc_ext_external;
  84
  85 #define MY_swap_ext_reloc_out MY (swap_ext_reloc_out)
  86 static void MY (swap_ext_reloc_out) (bfd *, arelent *, struct reloc_ext_external *);
  87
  88 #define MY_swap_ext_reloc_in MY (swap_ext_reloc_in)
  89 static void MY (swap_ext_reloc_in) (bfd *, struct reloc_ext_external *,
  90                                     arelent *, asymbol **, bfd_size_type);
  91
  92 #define MY_set_sizes MY (set_sizes)
  93 static bfd_boolean MY (set_sizes) (bfd *);
  94
  95 /* To set back reloc_size to ext, we make MY (set_sizes) be called
  96    through this construct.  Note that MY_set_arch_mach is only called
  97    through SET_ARCH_MACH.  The default bfd_default_set_arch_mach will
  98    not call set_sizes.  */
  99
 100 #define MY_set_arch_mach NAME (aout, set_arch_mach)
 101 #define SET_ARCH_MACH(BFD, EXEC) \
 102  MY_set_arch_mach (BFD, DEFAULT_ARCH, N_MACHTYPE (EXEC))
 103
 104 /* These macros describe the binary layout of the reloc information we
 105    use in a file.  */
 106 #define RELOC_EXT_BITS_EXTERN_LITTLE  0x80
 107 #define RELOC_EXT_BITS_TYPE_LITTLE    3
 108 #define RELOC_EXT_BITS_TYPE_SH_LITTLE 0
 109
 110 #ifndef MY_get_section_contents
 111 #define MY_get_section_contents aout_32_get_section_contents
 112 #endif
 113
 114 #define MACHTYPE_OK(mtype) ((mtype) == M_CRIS)
 115
 116 /* Include generic functions (some are overridden above).  */
 117 #include "aout32.c"
 118 #include "aout-target.h"
 119
 120 /* We need our own version to set header flags.  */
 121
 122 static bfd_boolean
 123 MY (write_object_contents) (bfd *abfd)
 124 {
 125   struct external_exec exec_bytes;
 126   struct internal_exec *execp = exec_hdr (abfd);
 127
 128   /* We set the reloc type to RELOC_EXT_SIZE, although setting it at all
 129      seems unnecessary when inspecting as and ld behavior (not an
 130      exhaustive inspection).  The default write_object_contents
 131      definition sets RELOC_EXT_SIZE, so we follow suite and set it too.  */
 132   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 133
 134   /* Setting N_SET_MACHTYPE and using N_SET_FLAGS is not performed by
 135      the default definition.  */
 136   if (bfd_get_arch (abfd) == bfd_arch_cris)
 137     N_SET_MACHTYPE (*execp, M_CRIS);
 138
 139   N_SET_FLAGS (*execp, aout_backend_info (abfd)->exec_hdr_flags);
 140
 141   WRITE_HEADERS (abfd, execp);
 142
 143   return TRUE;
 144 }
 145
 146 /* We need our own for these reasons:
 147    - Assert that a normal 8, 16 or 32 reloc is output.
 148    - Fix what seems to be a weak-bug (perhaps there for valid reasons).  */
 149
 150 static void
 151 MY (swap_ext_reloc_out) (bfd *abfd,
 152                          arelent *g,
 153                          struct reloc_ext_external *natptr)
 154 {
 155   int r_index;
 156   int r_extern;
 157   unsigned int r_type;
 158   bfd_vma r_addend;
 159   asymbol *sym = *(g->sym_ptr_ptr);
 160   asection *output_section = sym->section->output_section;
 161
 162   PUT_WORD (abfd, g->address, natptr->r_address);
 163
 164   r_type = (unsigned int) g->howto->type;
 165
 166   r_addend = g->addend;
 167   if ((sym->flags & BSF_SECTION_SYM) != 0)
 168     r_addend += (*(g->sym_ptr_ptr))->section->output_section->vma;
 169
 170   /* If this relocation is relative to a symbol then set the
 171      r_index to the symbols index, and the r_extern bit.
 172
 173      Absolute symbols can come in in two ways, either as an offset
 174      from the abs section, or as a symbol which has an abs value.
 175      check for that here.  */
 176
 177   if (bfd_is_abs_section (bfd_get_section (sym)))
 178     {
 179       r_extern = 0;
 180       r_index = N_ABS;
 181     }
 182   else if ((sym->flags & BSF_SECTION_SYM) == 0)
 183     {
 184       if (bfd_is_und_section (bfd_get_section (sym))
 185           /* Remember to check for weak symbols; they count as global.  */
 186           || (sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
 187         r_extern = 1;
 188       else
 189         r_extern = 0;
 190       r_index = (*(g->sym_ptr_ptr))->KEEPIT;
 191     }
 192   else
 193     {
 194       /* Just an ordinary section.  */
 195       r_extern = 0;
 196       r_index = output_section->target_index;
 197     }
 198
 199   /* The relocation type is the same as the canonical ones, but only
 200      the first 3 are used: RELOC_8, RELOC_16, RELOC_32.
 201      We may change this later, but assert this for the moment.  */
 202   if (r_type > 2)
 203     {
 204       (*_bfd_error_handler) (_("%s: Invalid relocation type exported: %d"),
 205                              bfd_get_filename (abfd), r_type);
 206
 207       bfd_set_error (bfd_error_wrong_format);
 208     }
 209
 210   /* Now the fun stuff.  */
 211   natptr->r_index[2] = r_index >> 16;
 212   natptr->r_index[1] = r_index >> 8;
 213   natptr->r_index[0] = r_index;
 214   natptr->r_type[0] =
 215      (r_extern ? RELOC_EXT_BITS_EXTERN_LITTLE : 0)
 216       | (r_type << RELOC_EXT_BITS_TYPE_SH_LITTLE);
 217
 218   PUT_WORD (abfd, r_addend, natptr->r_addend);
 219 }
 220
 221 /* We need our own to assert that a normal 8, 16 or 32 reloc is input.  */
 222
 223 static void
 224 MY (swap_ext_reloc_in) (bfd *abfd,
 225                         struct reloc_ext_external *bytes,
 226                         arelent *cache_ptr,
 227                         asymbol **symbols,
 228                         bfd_size_type symcount)
 229 {
 230   unsigned int r_index;
 231   int r_extern;
 232   unsigned int r_type;
 233   struct aoutdata *su = &(abfd->tdata.aout_data->a);
 234
 235   cache_ptr->address = (GET_SWORD (abfd, bytes->r_address));
 236
 237   /* Now the fun stuff.  */
 238   r_index =  (bytes->r_index[2] << 16)
 239     | (bytes->r_index[1] << 8)
 240     |  bytes->r_index[0];
 241   r_extern = (0 != (bytes->r_type[0] & RELOC_EXT_BITS_EXTERN_LITTLE));
 242   r_type = ((bytes->r_type[0]) >> RELOC_EXT_BITS_TYPE_SH_LITTLE)
 243     & RELOC_EXT_BITS_TYPE_LITTLE;
 244
 245   if (r_type > 2)
 246     {
 247       (*_bfd_error_handler) (_("%B: Invalid relocation type imported: %d"),
 248                              abfd, r_type);
 249
 250       bfd_set_error (bfd_error_wrong_format);
 251     }
 252
 253   cache_ptr->howto =  howto_table_ext + r_type;
 254
 255   if (r_extern && r_index > symcount)
 256     {
 257       (*_bfd_error_handler)
 258         (_("%B: Bad relocation record imported: %d"), abfd, r_index);
 259
 260       bfd_set_error (bfd_error_wrong_format);
 261
 262       /* We continue, so we can catch further errors.  */
 263       r_extern = 0;
 264       r_index = N_ABS;
 265     }
 266
 267   /* Magically uses r_extern, symbols etc.  Ugly, but it's what's in the
 268      default.  */
 269   MOVE_ADDRESS (GET_SWORD (abfd, bytes->r_addend));
 270 }
 271
 272 /* We use the same as the default, except that we also set
 273    "obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;", to avoid changing
 274    NAME (aout, set_arch_mach) in aoutx.  */
 275
 276 static bfd_boolean
 277 MY (set_sizes) (bfd *abfd)
 278 {
 279   /* Just as the default in aout-target.h (with some #ifdefs folded)...  */
 280
 281   adata (abfd).page_size = TARGET_PAGE_SIZE;
 282   adata (abfd).segment_size = SEGMENT_SIZE;
 283   adata (abfd).zmagic_disk_block_size = ZMAGIC_DISK_BLOCK_SIZE;
 284   adata (abfd).exec_bytes_size = EXEC_BYTES_SIZE;
 285
 286   /* ... except for that we have the extended reloc.  The alternative
 287      would be to add a check on bfd_arch_cris in NAME (aout,
 288      set_arch_mach) in aoutx.h, but I don't want to do that since
 289      target-specific things should not be added there.  */
 290
 291   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 292
 293   return TRUE;
 294 }