aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/cris/dl-machine.h
blob: beec38184d4c94a7a11e2a433057a4175676611d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
/* Machine-dependent ELF dynamic relocation inline functions.  CRIS version.
   Copyright (C) 1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If
   not, write to the Free Software Foundation, Inc.,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#ifndef dl_machine_h
#define dl_machine_h

#define ELF_MACHINE_NAME "CRIS"

#include <sys/param.h>

#ifdef __PIC__
# define CALL_FN(x)							      \
	"move.d	$pc,$r9\n\t"						      \
	"add.d	" #x " - .,$r9\n\t"					      \
	"jsr	$r9"
#else
# define CALL_FN(x) "jsr " #x
#endif

/* Return nonzero iff ELF header is compatible with the running host.  */

static inline int
elf_machine_matches_host (const Elf32_Ehdr *ehdr)
{
  return ehdr->e_machine == EM_CRIS;
}

/* Return the link-time address of _DYNAMIC.  Conveniently, this is the
   first element of the GOT.  This must be inlined in a function which
   uses global data.  */

static inline Elf32_Addr
elf_machine_dynamic (void)
{
  /* Don't just set this to an asm variable "r0" since that's not logical
     (like, the variable is uninitialized and the register is fixed) and
     may make GCC trip over itself doing register allocation.  Yes, I'm
     paranoid.  Why do you ask?  */
  Elf32_Addr *got;

  __asm__ ("move.d $r0,%0" : "=rm" (got));
  return *got;
}

/* Return the run-time load address of the shared object.  We do it like
   m68k and i386, by taking an arbitrary local symbol, forcing a GOT entry
   for it, and peeking into the GOT table, which is set to the link-time
   file-relative symbol value (regardless of whether the target is REL or
   RELA).  We subtract this link-time file-relative value from the "local"
   value we calculate from GOT position and GOT offset.  FIXME: Perhaps
   there's some other symbol we could use, that we don't *have* to force a
   GOT entry for.  */

static inline Elf32_Addr
elf_machine_load_address (void)
{
  Elf32_Addr gotaddr_diff;
  __asm__ ("sub.d [$r0+_dl_start:GOT16],$r0,%0\n\t"
	   "add.d _dl_start:GOTOFF,%0" : "=r" (gotaddr_diff));
  return gotaddr_diff;
}

/* Set up the loaded object described by L so its unrelocated PLT
   entries will jump to the on-demand fixup code in dl-runtime.c.  */

static inline int
elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
{
  Elf32_Addr *got;
  extern void _dl_runtime_resolve (Elf32_Word);
  extern void _dl_runtime_profile (Elf32_Word);

  if (l->l_info[DT_JMPREL] && lazy)
    {
      /* The GOT entries for functions in the PLT have not yet been
	 filled in.  Their initial contents will arrange when called
	 to push an offset into the .rela.plt section, push
	 _GLOBAL_OFFSET_TABLE_[1], and then jump to
	 _GLOBAL_OFFSET_TABLE_[2].  */
      got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
      got[1] = (Elf32_Addr) l;	/* Identify this shared object.  */

      /* The got[2] entry contains the address of a function which gets
	 called to get the address of a so far unresolved function and
	 jump to it.  The profiling extension of the dynamic linker allows
	 to intercept the calls to collect information.  In this case we
	 don't store the address in the GOT so that all future calls also
	 end in this function.  */
      if (__builtin_expect (profile, 0))
	{
	  got[2] = (Elf32_Addr) &_dl_runtime_profile;

	  if (_dl_name_match_p (_dl_profile, l))
	    {
	      /* This is the object we are looking for.  Say that we really
		 want profiling and the timers are started.  */
	      _dl_profile_map = l;
	    }
	}
      else
	/* This function will get called to fix up the GOT entry indicated by
	   the offset on the stack, and then jump to the resolved address.  */
	got[2] = (Elf32_Addr) &_dl_runtime_resolve;
    }

  return lazy;
}

/* This code is used in dl-runtime.c to call the `fixup' function
   and then redirect to the address it returns.

   We get here with the offset into the relocation table pushed on stack,
   and the link map in MOF.  */

#define TRAMPOLINE_TEMPLATE(tramp_name, fixup_name) \
"; Trampoline for " #fixup_name "
	.globl " #tramp_name "
	.type " #tramp_name ", @function
" #tramp_name ":
	push	$r13
	push	$r12
	push	$r11
	push	$r10
	push	$r9
	push	$srp
	move.d	[$sp+6*4],$r11
	move	$mof,$r10
	" CALL_FN (fixup_name) "
	move.d	$r10,[$sp+6*4]
	pop	$srp
	pop	$r9
	pop	$r10
	pop	$r11
	pop	$r12
	pop	$r13
	jump	[$sp+]
	.size " #tramp_name ", . - " #tramp_name "\n"
#ifndef PROF
#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
asm (TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup) \
     TRAMPOLINE_TEMPLATE (_dl_runtime_profile, profile_fixup));
#else
#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
asm (TRAMPOLINE_TEMPLATE (_dl_runtime_resolve, fixup) \
     ".globl _dl_runtime_profile\n" \
     ".set _dl_runtime_profile, _dl_runtime_resolve");
#endif


/* Mask identifying addresses reserved for the user program,
   where the dynamic linker should not map anything.  */
#define ELF_MACHINE_USER_ADDRESS_MASK	0xf8000000UL

/* Initial entry point code for the dynamic linker.
   The C function `_dl_start' is the real entry point;
   its return value is the user program's entry point.  */

#define RTLD_START asm ("\
	.text
	.globl	_start
	.type	_start,@function
_start:
	move.d	$sp,$r10
	" CALL_FN (_dl_start) "
	/* FALLTHRU */

	.globl _dl_start_user
	.type _dl_start_user,@function
_dl_start_user:
	; Save the user entry point address in R1.
	move.d	$r10,$r1
	; Point R0 at the GOT.
	move.d	$pc,$r0
	sub.d	.:GOTOFF,$r0
	; Remember the highest stack address.
	move.d	[$r0+__libc_stack_end:GOT16],$r13
	move.d	$sp,[$r13]
	; See if we were run as a command with the executable file
	; name as an extra leading argument.
	move.d	[$r0+_dl_skip_args:GOT16],$r13
	move.d	[$r13],$r9
	; Get the original argument count
	move.d	[$sp],$r11
	; Subtract _dl_skip_args from it.
	sub.d	$r9,$r11
	; Adjust the stack pointer to skip _dl_skip_args words.
	addi	$r9.d,$sp
	; Put the new argc in place as expected by the user entry.
	move.d	$r11,[$sp]
	; Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env)
	;  env: skip scaled argc and skip stored argc and NULL at end of argv[].
	move.d	$sp,$r13
	addi	$r11.d,$r13
	addq	8,$r13
	;  argv: skip stored argc.
	move.d	$sp,$r12
	addq	4,$r12
	;  main_map: at _dl_loaded.
	move.d	[$r0+_dl_loaded:GOT16],$r9
	move.d	[$r9],$r10
	move.d	_dl_init:PLTG,$r9
	add.d	$r0,$r9
	jsr	$r9
	; Pass our finalizer function to the user in R10.
	move.d [$r0+_dl_fini:GOT16],$r10
	; Terminate the frame-pointer.
	moveq	0,$r8
	; Cause SEGV if user entry returns.
	move	$r8,$srp
	; Jump to the user's entry point.
	jump	$r1
	.size _dl_start_user, . - _dl_start_user
	.previous");

/* Nonzero iff TYPE describes a relocation that should
   skip the executable when looking up the symbol value.  */
#define elf_machine_lookup_noexec_p(type) ((type) == R_CRIS_COPY)

/* Nonzero iff TYPE describes relocation of a PLT entry, so
   PLT entries should not be allowed to define the value.  */
#define elf_machine_lookup_noplt_p(type) ((type) == R_CRIS_JUMP_SLOT)

/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.  */
#define ELF_MACHINE_JMP_SLOT	R_CRIS_JUMP_SLOT

/* CRIS never uses Elf32_Rel relocations.  */
#define ELF_MACHINE_NO_REL 1

/* We define an initialization functions.  This is called very early in
   _dl_sysdep_start.  */
#define DL_PLATFORM_INIT dl_platform_init ()

extern const char *_dl_platform;

static inline void __attribute__ ((unused))
dl_platform_init (void)
{
  if (_dl_platform != NULL && *_dl_platform == '\0')
    /* Avoid an empty string which would disturb us.  */
    _dl_platform = NULL;
}

static inline Elf32_Addr
elf_machine_fixup_plt (struct link_map *map, lookup_t t,
		       const Elf32_Rela *reloc,
		       Elf32_Addr *reloc_addr, Elf32_Addr value)
{
  return *reloc_addr = value;
}

/* Return the final value of a plt relocation.  */
static inline Elf32_Addr
elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
		       Elf32_Addr value)
{
  return value + reloc->r_addend;
}

#endif /* !dl_machine_h */

#ifdef RESOLVE

/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
   MAP is the object containing the reloc.  */

static inline void
elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,
		  const Elf32_Sym *sym, const struct r_found_version *version,
		  Elf32_Addr *const reloc_addr)
{
#ifndef RTLD_BOOTSTRAP
  /* This is defined in rtld.c, but nowhere in the static libc.a; make the
     reference weak so static programs can still link.  This declaration
     cannot be done when compiling rtld.c (i.e.  #ifdef RTLD_BOOTSTRAP)
     because rtld.c contains the common defn for _dl_rtld_map, which is
     incompatible with a weak decl in the same file.  */
  weak_extern (_dl_rtld_map);
#endif

  if (ELF32_R_TYPE (reloc->r_info) == R_CRIS_RELATIVE)
    {
#ifndef RTLD_BOOTSTRAP
      if (map != &_dl_rtld_map) /* Already done in rtld itself. */
#endif
	*reloc_addr = map->l_addr + reloc->r_addend;
    }
  else
    {
#ifndef RTLD_BOOTSTRAP
      const Elf32_Sym *const refsym = sym;
#endif
      Elf32_Addr value;
      if (sym->st_shndx != SHN_UNDEF &&
	  ELF32_ST_BIND (sym->st_info) == STB_LOCAL)
	value = map->l_addr;
      else
	{
	  value = RESOLVE (&sym, version, ELF32_R_TYPE (reloc->r_info));
	  if (sym)
	    value += sym->st_value;
	}
      value += reloc->r_addend;	/* Assume copy relocs have zero addend.  */

      switch (ELF32_R_TYPE (reloc->r_info))
	{
#ifndef RTLD_BOOTSTRAP
	case R_CRIS_COPY:
	  if (sym == NULL)
	    /* This can happen in trace mode if an object could not be
	       found.  */
	    break;
	  if (sym->st_size > refsym->st_size
	      || (_dl_verbose && sym->st_size < refsym->st_size))
	    {
	      extern char **_dl_argv;
	      const char *strtab;

	      strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
	      _dl_error_printf ("\
%s: Symbol `%s' has different size in shared object, consider re-linking\n",
				_dl_argv[0] ?: "<program name unknown>",
				strtab + refsym->st_name);
	    }
	  memcpy (reloc_addr, (void *) value, MIN (sym->st_size,
						   refsym->st_size));
	  break;

	case R_CRIS_32:
#endif
	case R_CRIS_GLOB_DAT:
	case R_CRIS_JUMP_SLOT:
	  *reloc_addr = value;
	  break;
#ifndef RTLD_BOOTSTRAP
	case R_CRIS_8:
	  *(char *) reloc_addr = value;
	  break;
	case R_CRIS_16:
	  *(short *) reloc_addr = value;
	  break;
	case R_CRIS_8_PCREL:
	  *(char *) reloc_addr
	    = value + reloc->r_addend - (Elf32_Addr) reloc_addr - 1;
	  break;
	case R_CRIS_16_PCREL:
	  *(short *) reloc_addr
	    = value + reloc->r_addend - (Elf32_Addr) reloc_addr - 2;
	  break;
	case R_CRIS_32_PCREL:
	  *reloc_addr = value + reloc->r_addend - (Elf32_Addr) reloc_addr - 4;
	  break;
#endif
	case R_CRIS_NONE:
	  break;
#if !defined RTLD_BOOTSTRAP || defined _NDEBUG
	default:
	  _dl_reloc_bad_type (map, ELFW(R_TYPE) (reloc->r_info), 0);
	  break;
#endif
	}
    }
}

static inline void
elf_machine_lazy_rel (struct link_map *map,
		      Elf32_Addr l_addr, const Elf32_Rela *reloc)
{
  Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
  if (__builtin_expect (ELF32_R_TYPE (reloc->r_info), R_CRIS_JUMP_SLOT)
      == R_CRIS_JUMP_SLOT)
    *reloc_addr += l_addr;
  else
    _dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1);
}

#endif /* RESOLVE */