bfd/aout-cris.c

   1 /* BFD backend for CRIS a.out binaries.
   2    Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2009, 2012
   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  Beware; some of the information there is outdated.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 "sysdep.h"
  70 #include "bfd.h"
  71
  72 /* Version 1 of the header.  */
  73 #define MY_exec_hdr_flags 1
  74
  75 #define MY_write_object_contents MY (write_object_contents)
  76 static bfd_boolean MY (write_object_contents) (bfd *);
  77
  78 /* Forward this, so we can use a pointer to it in PARAMS.  */
  79 struct reloc_ext_external;
  80
  81 #define MY_swap_ext_reloc_out MY (swap_ext_reloc_out)
  82 static void MY (swap_ext_reloc_out) (bfd *, arelent *, struct reloc_ext_external *);
  83
  84 #define MY_swap_ext_reloc_in MY (swap_ext_reloc_in)
  85 static void MY (swap_ext_reloc_in) (bfd *, struct reloc_ext_external *,
  86                                     arelent *, asymbol **, bfd_size_type);
  87
  88 #define MY_set_sizes MY (set_sizes)
  89 static bfd_boolean MY (set_sizes) (bfd *);
  90
  91 /* To set back reloc_size to ext, we make MY (set_sizes) be called
  92    through this construct.  Note that MY_set_arch_mach is only called
  93    through SET_ARCH_MACH.  The default bfd_default_set_arch_mach will
  94    not call set_sizes.  */
  95
  96 #define MY_set_arch_mach NAME (aout, set_arch_mach)
  97 #define SET_ARCH_MACH(BFD, EXEC) \
  98  MY_set_arch_mach (BFD, DEFAULT_ARCH, N_MACHTYPE (EXEC))
  99
 100 /* These macros describe the binary layout of the reloc information we
 101    use in a file.  */
 102 #define RELOC_EXT_BITS_EXTERN_LITTLE  0x80
 103 #define RELOC_EXT_BITS_TYPE_LITTLE    3
 104 #define RELOC_EXT_BITS_TYPE_SH_LITTLE 0
 105
 106 #ifndef MY_get_section_contents
 107 #define MY_get_section_contents aout_32_get_section_contents
 108 #endif
 109
 110 #define MACHTYPE_OK(mtype) ((mtype) == M_CRIS)
 111
 112 /* Include generic functions (some are overridden above).  */
 113 #include "aout32.c"
 114 #include "aout-target.h"
 115
 116 /* We need our own version to set header flags.  */
 117
 118 static bfd_boolean
 119 MY (write_object_contents) (bfd *abfd)
 120 {
 121   struct external_exec exec_bytes;
 122   struct internal_exec *execp = exec_hdr (abfd);
 123
 124   /* We set the reloc type to RELOC_EXT_SIZE, although setting it at all
 125      seems unnecessary when inspecting as and ld behavior (not an
 126      exhaustive inspection).  The default write_object_contents
 127      definition sets RELOC_EXT_SIZE, so we follow suite and set it too.  */
 128   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 129
 130   /* Setting N_SET_MACHTYPE and using N_SET_FLAGS is not performed by
 131      the default definition.  */
 132   if (bfd_get_arch (abfd) == bfd_arch_cris)
 133     N_SET_MACHTYPE (*execp, M_CRIS);
 134
 135   N_SET_FLAGS (*execp, aout_backend_info (abfd)->exec_hdr_flags);
 136
 137   WRITE_HEADERS (abfd, execp);
 138
 139   return TRUE;
 140 }
 141
 142 /* We need our own for these reasons:
 143    - Assert that a normal 8, 16 or 32 reloc is output.
 144    - Fix what seems to be a weak-bug (perhaps there for valid reasons).  */
 145
 146 static void
 147 MY (swap_ext_reloc_out) (bfd *abfd,
 148                          arelent *g,
 149                          struct reloc_ext_external *natptr)
 150 {
 151   int r_index;
 152   int r_extern;
 153   unsigned int r_type;
 154   bfd_vma r_addend;
 155   asymbol *sym = *(g->sym_ptr_ptr);
 156   asection *output_section = sym->section->output_section;
 157
 158   PUT_WORD (abfd, g->address, natptr->r_address);
 159
 160   r_type = (unsigned int) g->howto->type;
 161
 162   r_addend = g->addend;
 163   if ((sym->flags & BSF_SECTION_SYM) != 0)
 164     r_addend += (*(g->sym_ptr_ptr))->section->output_section->vma;
 165
 166   /* If this relocation is relative to a symbol then set the
 167      r_index to the symbols index, and the r_extern bit.
 168
 169      Absolute symbols can come in in two ways, either as an offset
 170      from the abs section, or as a symbol which has an abs value.
 171      check for that here.  */
 172
 173   if (bfd_is_abs_section (bfd_get_section (sym)))
 174     {
 175       r_extern = 0;
 176       r_index = N_ABS;
 177     }
 178   else if ((sym->flags & BSF_SECTION_SYM) == 0)
 179     {
 180       if (bfd_is_und_section (bfd_get_section (sym))
 181           /* Remember to check for weak symbols; they count as global.  */
 182           || (sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
 183         r_extern = 1;
 184       else
 185         r_extern = 0;
 186       r_index = (*(g->sym_ptr_ptr))->KEEPIT;
 187     }
 188   else
 189     {
 190       /* Just an ordinary section.  */
 191       r_extern = 0;
 192       r_index = output_section->target_index;
 193     }
 194
 195   /* The relocation type is the same as the canonical ones, but only
 196      the first 3 are used: RELOC_8, RELOC_16, RELOC_32.
 197      We may change this later, but assert this for the moment.  */
 198   if (r_type > 2)
 199     {
 200       (*_bfd_error_handler) (_("%s: Invalid relocation type exported: %d"),
 201                              bfd_get_filename (abfd), r_type);
 202
 203       bfd_set_error (bfd_error_wrong_format);
 204     }
 205
 206   /* Now the fun stuff.  */
 207   natptr->r_index[2] = r_index >> 16;
 208   natptr->r_index[1] = r_index >> 8;
 209   natptr->r_index[0] = r_index;
 210   natptr->r_type[0] =
 211      (r_extern ? RELOC_EXT_BITS_EXTERN_LITTLE : 0)
 212       | (r_type << RELOC_EXT_BITS_TYPE_SH_LITTLE);
 213
 214   PUT_WORD (abfd, r_addend, natptr->r_addend);
 215 }
 216
 217 /* We need our own to assert that a normal 8, 16 or 32 reloc is input.  */
 218
 219 static void
 220 MY (swap_ext_reloc_in) (bfd *abfd,
 221                         struct reloc_ext_external *bytes,
 222                         arelent *cache_ptr,
 223                         asymbol **symbols,
 224                         bfd_size_type symcount)
 225 {
 226   unsigned int r_index;
 227   int r_extern;
 228   unsigned int r_type;
 229   struct aoutdata *su = &(abfd->tdata.aout_data->a);
 230
 231   cache_ptr->address = (GET_SWORD (abfd, bytes->r_address));
 232
 233   /* Now the fun stuff.  */
 234   r_index =  (bytes->r_index[2] << 16)
 235     | (bytes->r_index[1] << 8)
 236     |  bytes->r_index[0];
 237   r_extern = (0 != (bytes->r_type[0] & RELOC_EXT_BITS_EXTERN_LITTLE));
 238   r_type = ((bytes->r_type[0]) >> RELOC_EXT_BITS_TYPE_SH_LITTLE)
 239     & RELOC_EXT_BITS_TYPE_LITTLE;
 240
 241   if (r_type > 2)
 242     {
 243       (*_bfd_error_handler) (_("%B: Invalid relocation type imported: %d"),
 244                              abfd, r_type);
 245
 246       bfd_set_error (bfd_error_wrong_format);
 247     }
 248
 249   cache_ptr->howto =  howto_table_ext + r_type;
 250
 251   if (r_extern && r_index > symcount)
 252     {
 253       (*_bfd_error_handler)
 254         (_("%B: Bad relocation record imported: %d"), abfd, r_index);
 255
 256       bfd_set_error (bfd_error_wrong_format);
 257
 258       /* We continue, so we can catch further errors.  */
 259       r_extern = 0;
 260       r_index = N_ABS;
 261     }
 262
 263   /* Magically uses r_extern, symbols etc.  Ugly, but it's what's in the
 264      default.  */
 265   MOVE_ADDRESS (GET_SWORD (abfd, bytes->r_addend));
 266 }
 267
 268 /* We use the same as the default, except that we also set
 269    "obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;", to avoid changing
 270    NAME (aout, set_arch_mach) in aoutx.  */
 271
 272 static bfd_boolean
 273 MY (set_sizes) (bfd *abfd)
 274 {
 275   /* Just as the default in aout-target.h (with some #ifdefs folded)...  */
 276
 277   adata (abfd).page_size = TARGET_PAGE_SIZE;
 278   adata (abfd).segment_size = SEGMENT_SIZE;
 279   adata (abfd).zmagic_disk_block_size = ZMAGIC_DISK_BLOCK_SIZE;
 280   adata (abfd).exec_bytes_size = EXEC_BYTES_SIZE;
 281
 282   /* ... except for that we have the extended reloc.  The alternative
 283      would be to add a check on bfd_arch_cris in NAME (aout,
 284      set_arch_mach) in aoutx.h, but I don't want to do that since
 285      target-specific things should not be added there.  */
 286
 287   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 288
 289   return TRUE;
 290 }