bfd/aout-cris.c

   1 /* BFD backend for CRIS a.out binaries.
   2    Copyright (C) 2000-2017 Free Software Foundation, Inc.
   3    Contributed by Axis Communications AB.
   4    Written by Hans-Peter Nilsson.
   5
   6    This file is part of BFD, the Binary File Descriptor library.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21    MA 02110-1301, USA.  */
  22
  23 /* See info in the file PORTING for documentation of these macros and
  24    functions.  Beware; some of the information there is outdated.  */
  25
  26 #define N_HEADER_IN_TEXT(x) 0
  27 #define N_TXTOFF(x)         32
  28 #define ENTRY_CAN_BE_ZERO
  29 #define TEXT_START_ADDR     0
  30
  31 /* Without reading symbols to get the text start symbol, there is no way
  32    to know where the text segment starts in an a.out file.  Defaulting to
  33    anything as constant as TEXT_START_ADDR is bad.  But we can guess from
  34    the entry point, which is usually within the first 64k of the text
  35    segment.  We also assume here that the text segment is 64k-aligned.
  36    FIXME: It is also wrong to assume that data and bss follow immediately
  37    after text, but with those, we don't have any choice besides reading
  38    symbol info, and luckily there's no pressing need for correctness for
  39    those vma:s at this time.  */
  40 #define N_TXTADDR(x) ((x)->a_entry & ~(bfd_vma) 0xffff)
  41
  42 /* If you change this to 4, you can not link to an address N*4+2.  */
  43 #define SEGMENT_SIZE 2
  44
  45 /* For some reason, if the a.out file has Z_MAGIC, then
  46    adata(abfd).exec_bytes_size is not used, but rather
  47    adata(abfd).zmagic_disk_block_size, even though the exec_header is
  48    *not* included in the text segment.  A simple workaround is to
  49    #define ZMAGIC_DISK_BLOCK_SIZE, which is used if defined; otherwise
  50    TARGET_PAGE_SIZE is used.  */
  51 #define ZMAGIC_DISK_BLOCK_SIZE     N_TXTOFF (0)
  52
  53 /* It seems odd at first to set a page-size this low, but gives greater
  54    freedom in where things can be linked.  The drawback is that you have
  55    to set alignment and padding in linker scripts.  */
  56 #define TARGET_PAGE_SIZE SEGMENT_SIZE
  57 #define TARGETNAME "a.out-cris"
  58
  59 /* The definition here seems not used; just provided as a convention.  */
  60 #define DEFAULT_ARCH bfd_arch_cris
  61
  62 /* Do not "beautify" the CONCAT* macro args.  Traditional C will not
  63    remove whitespace added here, and thus will fail to concatenate
  64    the tokens.  */
  65 #define MY(OP) CONCAT2 (cris_aout_,OP)
  66 #define NAME(x, y) CONCAT3 (cris_aout,_32_,y)
  67
  68 #include "sysdep.h"
  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, EXECP) \
  97  MY_set_arch_mach (BFD, DEFAULT_ARCH, N_MACHTYPE (EXECP))
  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       /* xgettext:c-format */
 200       _bfd_error_handler (_("%B: Invalid relocation type exported: %d"),
 201                           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       /* xgettext:c-format */
 244       _bfd_error_handler (_("%B: Invalid relocation type imported: %d"),
 245                           abfd, r_type);
 246
 247       bfd_set_error (bfd_error_wrong_format);
 248     }
 249
 250   cache_ptr->howto =  howto_table_ext + r_type;
 251
 252   if (r_extern && r_index > symcount)
 253     {
 254       _bfd_error_handler
 255         /* xgettext:c-format */
 256         (_("%B: Bad relocation record imported: %d"), abfd, r_index);
 257
 258       bfd_set_error (bfd_error_wrong_format);
 259
 260       /* We continue, so we can catch further errors.  */
 261       r_extern = 0;
 262       r_index = N_ABS;
 263     }
 264
 265   /* Magically uses r_extern, symbols etc.  Ugly, but it's what's in the
 266      default.  */
 267   MOVE_ADDRESS (GET_SWORD (abfd, bytes->r_addend));
 268 }
 269
 270 /* We use the same as the default, except that we also set
 271    "obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;", to avoid changing
 272    NAME (aout, set_arch_mach) in aoutx.  */
 273
 274 static bfd_boolean
 275 MY (set_sizes) (bfd *abfd)
 276 {
 277   /* Just as the default in aout-target.h (with some #ifdefs folded)...  */
 278
 279   adata (abfd).page_size = TARGET_PAGE_SIZE;
 280   adata (abfd).segment_size = SEGMENT_SIZE;
 281   adata (abfd).zmagic_disk_block_size = ZMAGIC_DISK_BLOCK_SIZE;
 282   adata (abfd).exec_bytes_size = EXEC_BYTES_SIZE;
 283
 284   /* ... except for that we have the extended reloc.  The alternative
 285      would be to add a check on bfd_arch_cris in NAME (aout,
 286      set_arch_mach) in aoutx.h, but I don't want to do that since
 287      target-specific things should not be added there.  */
 288
 289   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 290
 291   return TRUE;
 292 }