bfd/aout-cris.c

   1 /* BFD backend for CRIS a.out binaries.
   2    Copyright (C) 2000-2022 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  Beware; some of the information there is outdated.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 /* Do not "beautify" the CONCAT* macro args.  Traditional C will not
  60    remove whitespace added here, and thus will fail to concatenate
  61    the tokens.  */
  62 #define MY(OP) CONCAT2 (cris_aout_,OP)
  63 #define NAME(x, y) CONCAT3 (cris_aout,_32_,y)
  64
  65 #include "sysdep.h"
  66 #include "bfd.h"
  67
  68 /* Version 1 of the header.  */
  69 #define MY_exec_hdr_flags 1
  70
  71 #define MY_write_object_contents MY (write_object_contents)
  72 static bool MY (write_object_contents) (bfd *);
  73
  74 /* Forward this, so we can use a pointer to it in PARAMS.  */
  75 struct reloc_ext_external;
  76
  77 #define MY_swap_ext_reloc_out MY (swap_ext_reloc_out)
  78 static void MY (swap_ext_reloc_out) (bfd *, arelent *, struct reloc_ext_external *);
  79
  80 #define MY_swap_ext_reloc_in MY (swap_ext_reloc_in)
  81 static void MY (swap_ext_reloc_in) (bfd *, struct reloc_ext_external *,
  82                                     arelent *, asymbol **, bfd_size_type);
  83
  84 #define MY_set_sizes MY (set_sizes)
  85 static bool MY (set_sizes) (bfd *);
  86
  87 /* To set back reloc_size to ext, we make MY (set_sizes) be called
  88    through this construct.  Note that MY_set_arch_mach is only called
  89    through SET_ARCH_MACH.  The default bfd_default_set_arch_mach will
  90    not call set_sizes.  */
  91
  92 #define SET_ARCH_MACH(BFD, EXECP) \
  93   bfd_set_arch_mach (BFD, bfd_arch_cris, N_MACHTYPE (EXECP))
  94
  95 /* These macros describe the binary layout of the reloc information we
  96    use in a file.  */
  97 #define RELOC_EXT_BITS_EXTERN_LITTLE  0x80
  98 #define RELOC_EXT_BITS_TYPE_LITTLE    3
  99 #define RELOC_EXT_BITS_TYPE_SH_LITTLE 0
 100
 101 #ifndef MY_get_section_contents
 102 #define MY_get_section_contents aout_32_get_section_contents
 103 #endif
 104
 105 #define MACHTYPE_OK(mtype) ((mtype) == M_CRIS)
 106
 107 /* Include generic functions (some are overridden above).  */
 108 #include "aout32.c"
 109 #include "aout-target.h"
 110
 111 /* We need our own version to set header flags.  */
 112
 113 static bool
 114 MY (write_object_contents) (bfd *abfd)
 115 {
 116   struct external_exec exec_bytes;
 117   struct internal_exec *execp = exec_hdr (abfd);
 118
 119   /* We set the reloc type to RELOC_EXT_SIZE, although setting it at all
 120      seems unnecessary when inspecting as and ld behavior (not an
 121      exhaustive inspection).  The default write_object_contents
 122      definition sets RELOC_EXT_SIZE, so we follow suite and set it too.  */
 123   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 124
 125   /* Setting N_SET_MACHTYPE and using N_SET_FLAGS is not performed by
 126      the default definition.  */
 127   if (bfd_get_arch (abfd) == bfd_arch_cris)
 128     N_SET_MACHTYPE (execp, M_CRIS);
 129
 130   N_SET_FLAGS (execp, aout_backend_info (abfd)->exec_hdr_flags);
 131
 132   WRITE_HEADERS (abfd, execp);
 133
 134   return true;
 135 }
 136
 137 /* We need our own for these reasons:
 138    - Assert that a normal 8, 16 or 32 reloc is output.
 139    - Fix what seems to be a weak-bug (perhaps there for valid reasons).  */
 140
 141 static void
 142 MY (swap_ext_reloc_out) (bfd *abfd,
 143                          arelent *g,
 144                          struct reloc_ext_external *natptr)
 145 {
 146   int r_index;
 147   int r_extern;
 148   unsigned int r_type;
 149   bfd_vma r_addend;
 150   asymbol *sym = *(g->sym_ptr_ptr);
 151   asection *output_section = sym->section->output_section;
 152
 153   PUT_WORD (abfd, g->address, natptr->r_address);
 154
 155   r_type = (unsigned int) g->howto->type;
 156
 157   r_addend = g->addend;
 158   if ((sym->flags & BSF_SECTION_SYM) != 0)
 159     r_addend += (*(g->sym_ptr_ptr))->section->output_section->vma;
 160
 161   /* If this relocation is relative to a symbol then set the
 162      r_index to the symbols index, and the r_extern bit.
 163
 164      Absolute symbols can come in in two ways, either as an offset
 165      from the abs section, or as a symbol which has an abs value.
 166      check for that here.  */
 167
 168   if (bfd_is_abs_section (bfd_asymbol_section (sym)))
 169     {
 170       r_extern = 0;
 171       r_index = N_ABS;
 172     }
 173   else if ((sym->flags & BSF_SECTION_SYM) == 0)
 174     {
 175       if (bfd_is_und_section (bfd_asymbol_section (sym))
 176           /* Remember to check for weak symbols; they count as global.  */
 177           || (sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
 178         r_extern = 1;
 179       else
 180         r_extern = 0;
 181       r_index = (*(g->sym_ptr_ptr))->KEEPIT;
 182     }
 183   else
 184     {
 185       /* Just an ordinary section.  */
 186       r_extern = 0;
 187       r_index = output_section->target_index;
 188     }
 189
 190   /* The relocation type is the same as the canonical ones, but only
 191      the first 3 are used: RELOC_8, RELOC_16, RELOC_32.
 192      We may change this later, but assert this for the moment.  */
 193   if (r_type > 2)
 194     {
 195       /* xgettext:c-format */
 196       _bfd_error_handler (_("%pB: unsupported relocation type exported: %#x"),
 197                           abfd, r_type);
 198
 199       bfd_set_error (bfd_error_wrong_format);
 200     }
 201
 202   /* Now the fun stuff.  */
 203   natptr->r_index[2] = r_index >> 16;
 204   natptr->r_index[1] = r_index >> 8;
 205   natptr->r_index[0] = r_index;
 206   natptr->r_type[0] =
 207      (r_extern ? RELOC_EXT_BITS_EXTERN_LITTLE : 0)
 208       | (r_type << RELOC_EXT_BITS_TYPE_SH_LITTLE);
 209
 210   PUT_WORD (abfd, r_addend, natptr->r_addend);
 211 }
 212
 213 /* We need our own to assert that a normal 8, 16 or 32 reloc is input.  */
 214
 215 static void
 216 MY (swap_ext_reloc_in) (bfd *abfd,
 217                         struct reloc_ext_external *bytes,
 218                         arelent *cache_ptr,
 219                         asymbol **symbols,
 220                         bfd_size_type symcount)
 221 {
 222   unsigned int r_index;
 223   int r_extern;
 224   unsigned int r_type;
 225   struct aoutdata *su = &(abfd->tdata.aout_data->a);
 226
 227   cache_ptr->address = (GET_SWORD (abfd, bytes->r_address));
 228
 229   /* Now the fun stuff.  */
 230   r_index =  (((unsigned int) bytes->r_index[2] << 16)
 231     | ((unsigned int) bytes->r_index[1] << 8)
 232     |  bytes->r_index[0]);
 233
 234   r_extern = (0 != (bytes->r_type[0] & RELOC_EXT_BITS_EXTERN_LITTLE));
 235
 236   r_type = ((bytes->r_type[0] & RELOC_EXT_BITS_TYPE_LITTLE)
 237     >> RELOC_EXT_BITS_TYPE_SH_LITTLE);
 238
 239   if (r_type > 2)
 240     {
 241       /* xgettext:c-format */
 242       _bfd_error_handler (_("%pB: unsupported relocation type imported: %#x"),
 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         /* xgettext:c-format */
 254         (_("%pB: 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 bool
 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 }