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1 /* BFD backend for CRIS a.out binaries.
2    Copyright (C) 2000-2014 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  Beware; some of the information there is outdated.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, 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
MY(write_object_contents)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
MY(swap_ext_reloc_out)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
MY(swap_ext_reloc_in)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
MY(set_sizes)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 }
290