about summary refs log tree commit diff
path: root/sysdeps/s390/s390-32/dl-machine.h
blob: 3b3d5bf36e55a7b4a1d8e812c021218f4ee76ca3 (plain) (blame)
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
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
/* Machine-dependent ELF dynamic relocation inline functions.  S390 Version.
   Copyright (C) 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
   Contributed by Carl Pederson & Martin Schwidefsky.
   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 Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; 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 "s390"

#include <sys/param.h>
#include <string.h>
#include <link.h>

/* This is an older, now obsolete value.  */
#define EM_S390_OLD	0xA390

/* 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_S390 || ehdr->e_machine == EM_S390_OLD)
         && ehdr->e_ident[EI_CLASS] == ELFCLASS32;
}


/* 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)
{
  register Elf32_Addr *got;

  asm( "        bras   %0,2f\n"
       "1:      .long  _GLOBAL_OFFSET_TABLE_-1b\n"
       "2:      al     %0,0(%0)"
       : "=&a" (got) : : "0" );

  return *got;
}


/* Return the run-time load address of the shared object.  */
static inline Elf32_Addr
elf_machine_load_address (void)
{
  Elf32_Addr addr;

  asm( "   bras  1,2f\n"
       "1: .long _GLOBAL_OFFSET_TABLE_ - 1b\n"
       "   .long _dl_start - 1b - 0x80000000\n"
       "2: l     %0,4(1)\n"
       "   ar    %0,1\n"
       "   al    1,0(1)\n"
       "   sl    %0,_dl_start@GOT12(1)"
       : "=&d" (addr) : : "1" );
  return addr;
}

/* 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 __attribute__ ((unused))
elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
{
  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 .rel.plt section, push _GLOBAL_OFFSET_TABLE_[1],
	 and then jump to _GLOBAL_OFFSET_TABLE[2].  */
      Elf32_Addr *got;
      got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
      /* If a library is prelinked but we have to relocate anyway,
	 we have to be able to undo the prelinking of .got.plt.
	 The prelinker saved us here address of .plt + 0x2c.  */
      if (got[1])
	{
	  l->l_mach.plt = got[1] + l->l_addr;
	  l->l_mach.gotplt = (Elf32_Addr) &got[3];
	}
      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 (GL(dl_profile), l))
	    /* This is the object we are looking for.  Say that we really
	       want profiling and the timers are started.  */
	    GL(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.  */

/* s390:
   Arguments are in register.
   r2 - r7 holds the original parameters for the function call, fixup
   and trampoline code use r0-r5 and r14-15. For the correct function
   call r2-r5 and r14-15 must be restored.
   Arguments from the PLT are stored at 24(r15) and 28(r15)
   and must be moved to r2 and r3 for the fixup call (see elf32-s390.c
   in the binutils for the PLT code).
   Fixup function address in r2.
*/
#ifndef PROF
#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
  asm ( "\
    .text\n\
    .globl _dl_runtime_resolve\n\
    .type _dl_runtime_resolve, @function\n\
    .align 16\n\
_dl_runtime_resolve:\n\
    # save registers\n\
    stm    2,5,32(15)\n\
    st     14,48(15)\n\
    lr     0,15\n\
    ahi    15,-96\n\
    st     0,0(15)\n\
    # load args saved by PLT\n\
    lm     2,3,120(15)\n\
    basr   1,0\n\
0:  ahi    1,1f-0b\n\
    l      14,0(1)\n\
    bas    14,0(14,1)   # call fixup\n\
    lr     1,2          # function addr returned in r2\n\
    # restore registers\n\
    ahi    15,96\n\
    l      14,48(15)\n\
    lm     2,5,32(15)\n\
    br     1\n\
1:  .long  fixup-1b\n\
    .size _dl_runtime_resolve, .-_dl_runtime_resolve\n\
\n\
    .globl _dl_runtime_profile\n\
    .type _dl_runtime_profile, @function\n\
    .align 16\n\
_dl_runtime_profile:\n\
    # save registers\n\
    stm    2,5,32(15)\n\
    st     14,48(15)\n\
    lr     0,15\n\
    ahi    15,-96\n\
    st     0,0(15)\n\
    # load args saved by PLT\n\
    lm     2,3,120(15)\n\
    # load return address as third parameter\n\
    lr     4,14\n\
    basr   1,0\n\
0:  ahi    1,1f-0b\n\
    l      14,0(1)\n\
    bas    14,0(14,1)   # call fixup\n\
    lr     1,2          # function addr returned in r2\n\
    # restore registers\n\
    ahi    15,96\n\
    l      14,48(15)\n\
    lm     2,5,32(15)\n\
    br     1\n\
1:  .long  profile_fixup-1b\n\
    .size _dl_runtime_profile, .-_dl_runtime_profile\n\
");
#else
#define ELF_MACHINE_RUNTIME_TRAMPOLINE \
  asm ( "\
    .text\n\
    .globl _dl_runtime_resolve\n\
    .globl _dl_runtime_profile\n\
    .type _dl_runtime_resolve, @function\n\
    .type _dl_runtime_profile, @function\n\
    .align 16\n\
_dl_runtime_resolve:\n\
_dl_runtime_profile:\n\
    # save registers\n\
    stm    2,5,32(15)\n\
    st     14,48(15)\n\
    lr     0,15\n\
    ahi    15,-96\n\
    st     0,0(15)\n\
    # load args saved by PLT\n\
    lm     2,3,120(15)\n\
    # load return address as third parameter\n\
    lr     4,14\n\
    basr   1,0\n\
0:  ahi    1,1f-0b\n\
    l      14,0(1)\n\
    bas    14,0(14,1)   # call fixup\n\
    lr     1,2          # function addr returned in r2\n\
    # restore registers\n\
    ahi    15,96\n\
    l      14,48(15)\n\
    lm     2,5,32(15)\n\
    br     1\n\
1:  .long  fixup-1b\n\
    .size _dl_runtime_resolve, .-_dl_runtime_resolve\n\
    .size _dl_runtime_profile, .-_dl_runtime_profile\n\
");
#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 ("\n\
.text\n\
.align 4\n\
.globl _start\n\
.globl _dl_start_user\n\
_start:\n\
	basr  %r13,0\n\
.L0:    ahi   %r13,.Llit-.L0\n\
	lr    %r2,%r15\n\
	# Alloc stack frame\n\
	ahi   %r15,-96\n\
	# Set the back chain to zero\n\
	xc    0(4,%r15),0(%r15)\n\
	# Call _dl_start with %r2 pointing to arg on stack\n\
	l     %r14,.Ladr1-.Llit(%r13)\n\
	bas   %r14,0(%r14,%r13)   # call _dl_start\n\
_dl_start_user:\n\
	# Save the user entry point address in %r8.\n\
	lr    %r8,%r2\n\
	# Point %r12 at the GOT.\n\
	l     %r12,.Ladr0-.Llit(%r13)\n\
	ar    %r12,%r13\n\
	# Store the highest stack address\n\
	l     %r1,__libc_stack_end@GOT(%r12)\n\
	st    %r15, 0(%r1)\n\
	# See if we were run as a command with the executable file\n\
	# name as an extra leading argument.\n\
	l     %r1,_dl_skip_args@GOT12(0,%r12)\n\
	l     %r1,0(%r1)          # load _dl_skip_args\n\
	# Get the original argument count.\n\
	l     %r0,96(%r15)\n\
	# Subtract _dl_skip_args from it.\n\
	sr    %r0,%r1\n\
	# Adjust the stack pointer to skip _dl_skip_args words.\n\
	sll   %r1,2\n\
	ar    %r15,%r1\n\
	# Set the back chain to zero again\n\
	xc    0(4,%r15),0(%r15)\n\
	# Store back the modified argument count.\n\
	st    %r0,96(%r15)\n\
	# The special initializer gets called with the stack just\n\
	# as the application's entry point will see it; it can\n\
	# switch stacks if it moves these contents over.\n\
" RTLD_START_SPECIAL_INIT "\n\
	# Call the function to run the initializers.\n\
	# Load the parameters:\n\
	# (%r2, %r3, %r4, %r5) = (_dl_loaded, argc, argv, envp)\n\
	l     %r2,_rtld_local@GOT(%r12)\n\
	l     %r2,0(%r2)\n\
	l     %r3,96(%r15)\n\
	la    %r4,100(%r15)\n\
	lr    %r5,%r3\n\
	sll   %r5,2\n\
	la    %r5,104(%r5,%r15)\n\
	l     %r1,.Ladr4-.Llit(%r13)\n\
	bas   %r14,0(%r1,%r13)\n\
	# Pass our finalizer function to the user in %r14, as per ELF ABI.\n\
	l     %r14,_dl_fini@GOT(%r12)\n\
	# Free stack frame\n\
	ahi   %r15,96\n\
	# Jump to the user's entry point (saved in %r8).\n\
	br    %r8\n\
.Llit:\n\
.Ladr0: .long _GLOBAL_OFFSET_TABLE_-.Llit\n\
.Ladr1: .long _dl_start-.Llit\n\
.Ladr4: .long _dl_init_internal@PLT-.Llit\n\
");

#ifndef RTLD_START_SPECIAL_INIT
#define RTLD_START_SPECIAL_INIT /* nothing */
#endif

/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
   TLS variable, so undefined references should not be allowed to
   define the value.
   ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
   of the main executable's symbols, as for a COPY reloc.  */
#ifdef USE_TLS
# define elf_machine_type_class(type) \
  ((((type) == R_390_JMP_SLOT || (type) == R_390_TLS_DTPMOD		      \
     || (type) == R_390_TLS_DTPOFF || (type) == R_390_TLS_TPOFF)	      \
    * ELF_RTYPE_CLASS_PLT)						      \
   | (((type) == R_390_COPY) * ELF_RTYPE_CLASS_COPY))
#else
# define elf_machine_type_class(type) \
  ((((type) == R_390_JMP_SLOT) * ELF_RTYPE_CLASS_PLT)	\
   | (((type) == R_390_COPY) * ELF_RTYPE_CLASS_COPY))
#endif

/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.  */
#define ELF_MACHINE_JMP_SLOT    R_390_JMP_SLOT

/* The S390 never uses Elf32_Rel relocations.  */
#define ELF_MACHINE_NO_REL 1

/* The S390 overlaps DT_RELA and DT_PLTREL.  */
#define ELF_MACHINE_PLTREL_OVERLAP 1

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

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

#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,
		  void *const reloc_addr_arg)
{
  Elf32_Addr *const reloc_addr = reloc_addr_arg;
  const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);

#if !defined RTLD_BOOTSTRAP || !defined HAVE_Z_COMBRELOC
  if (__builtin_expect (r_type == R_390_RELATIVE, 0))
    {
# if !defined RTLD_BOOTSTRAP && !defined HAVE_Z_COMBRELOC
      /* 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.  */
#  ifndef SHARED
      weak_extern (GL(dl_rtld_map));
#  endif
      if (map != &GL(dl_rtld_map)) /* Already done in rtld itself.  */
# endif
	*reloc_addr = map->l_addr + reloc->r_addend;
    }
  else
#endif
  if (__builtin_expect (r_type == R_390_NONE, 0))
    return;
  else
    {
#ifndef RESOLVE_CONFLICT_FIND_MAP
      const Elf32_Sym *const refsym = sym;
#endif
#if defined USE_TLS && !defined RTLD_BOOTSTRAP
      struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
      Elf32_Addr value = sym == NULL ? 0 : sym_map->l_addr + sym->st_value;
#else
      Elf32_Addr value = RESOLVE (&sym, version, r_type);

# ifndef RTLD_BOOTSTRAP
      if (sym)
# endif
	value += sym->st_value;
#endif /* use TLS and !RTLD_BOOTSTRAP */

      switch (r_type)
	{
	case R_390_GLOB_DAT:
	case R_390_JMP_SLOT:
	  *reloc_addr = value + reloc->r_addend;
	  break;

#if defined USE_TLS && (!defined RTLD_BOOTSTRAP || USE___THREAD) \
    && !defined RESOLVE_CONFLICT_FIND_MAP
	case R_390_TLS_DTPMOD:
# ifdef RTLD_BOOTSTRAP
	  /* During startup the dynamic linker is always the module
	     with index 1.
	     XXX If this relocation is necessary move before RESOLVE
	     call.  */
	  *reloc_addr = 1;
# else
	  /* Get the information from the link map returned by the
	     resolv function.  */
	  if (sym_map != NULL)
	    *reloc_addr = sym_map->l_tls_modid;
# endif
	  break;
	case R_390_TLS_DTPOFF:
# ifndef RTLD_BOOTSTRAP
	  /* During relocation all TLS symbols are defined and used.
	     Therefore the offset is already correct.  */
	  if (sym != NULL)
	    *reloc_addr = sym->st_value + reloc->r_addend;
# endif
	  break;
	case R_390_TLS_TPOFF:
	  /* The offset is negative, forward from the thread pointer.  */
# ifdef RTLD_BOOTSTRAP
	  *reloc_addr = sym->st_value + reloc->r_addend - map->l_tls_offset;
# else
	  /* We know the offset of the object the symbol is contained in.
	     It is a negative value which will be added to the
	     thread pointer.  */
	  if (sym != NULL)
	    {
	      CHECK_STATIC_TLS (map, sym_map);
	      *reloc_addr = (sym->st_value + reloc->r_addend
			     - sym_map->l_tls_offset);
	    }
#endif
	  break;
#endif  /* use TLS */

#ifndef RTLD_BOOTSTRAP
# ifndef RESOLVE_CONFLICT_FIND_MAP
	/* Not needed in dl-conflict.c.  */
	case R_390_COPY:
	  if (sym == NULL)
	    /* This can happen in trace mode if an object could not be
	       found.  */
	    break;
	  if (__builtin_expect (sym->st_size > refsym->st_size, 0)
	      || (__builtin_expect (sym->st_size < refsym->st_size, 0)
		  && __builtin_expect (GL(dl_verbose), 0)))
	    {
	      const char *strtab;

	      strtab = (const char *) D_PTR(map,l_info[DT_STRTAB]);
	      _dl_error_printf ("\
%s: Symbol `%s' has different size in shared object, consider re-linking\n",
				rtld_progname ?: "<program name unknown>",
				strtab + refsym->st_name);
	    }
	  memcpy (reloc_addr_arg, (void *) value,
		  MIN (sym->st_size, refsym->st_size));
	  break;
# endif
	case R_390_32:
	  *reloc_addr = value + reloc->r_addend;
	  break;
	case R_390_16:
	  *(unsigned short *) reloc_addr = value + reloc->r_addend;
	  break;
	case R_390_8:
	  *(char *) reloc_addr = value + reloc->r_addend;
	  break;
# ifndef RESOLVE_CONFLICT_FIND_MAP
	case R_390_PC32:
	  *reloc_addr = value + reloc->r_addend - (Elf32_Addr) reloc_addr;
	  break;
	case R_390_PC16DBL:
	case R_390_PLT16DBL:
	  *(unsigned short *) reloc_addr = (unsigned short)
	    ((short) (value + reloc->r_addend - (Elf32_Addr) reloc_addr) >> 1);
	  break;
	case R_390_PC16:
	  *(unsigned short *) reloc_addr =
	    value + reloc->r_addend - (Elf32_Addr) reloc_addr;
	  break;
	case R_390_NONE:
	  break;
# endif
#endif
#if !defined(RTLD_BOOTSTRAP) || defined(_NDEBUG)
	default:
	  /* We add these checks in the version to relocate ld.so only
	     if we are still debugging.	 */
	  _dl_reloc_bad_type (map, r_type, 0);
	  break;
#endif
	}
    }
}

static inline void
elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc,
			   void *const reloc_addr_arg)
{
  Elf32_Addr *const reloc_addr = reloc_addr_arg;
  *reloc_addr = l_addr + reloc->r_addend;
}

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);
  const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
  /* Check for unexpected PLT reloc type.  */
  if (__builtin_expect (r_type == R_390_JMP_SLOT, 1))
    {
      if (__builtin_expect (map->l_mach.plt, 0) == 0)
	*reloc_addr += l_addr;
      else
	*reloc_addr =
	  map->l_mach.plt
	  + (((Elf32_Addr) reloc_addr) - map->l_mach.gotplt) * 8;
    }
  else
    _dl_reloc_bad_type (map, r_type, 1);
}

#endif /* RESOLVE */