about summary refs log tree commit diff
path: root/sysdeps/sparc/dl-machine.h
blob: ad288e15b2ea6f002091e6df708e90920279fd6a (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
/* Machine-dependent ELF dynamic relocation inline functions.  SPARC version.
   Copyright (C) 1996 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.  */

#define ELF_MACHINE_NAME "sparc"

#include <assert.h>
#include <string.h>
#include <link.h>


/* Some SPARC opcodes we need to use for self-modifying code.  */
#define OPCODE_NOP	0x01000000 /* nop */
#define OPCODE_CALL	0x04000000 /* call ?; add PC-rel word address */
#define OPCODE_SETHI_G1	0x03000000 /* sethi ?, %g1; add value>>10 */
#define OPCODE_JMP_G1	0x81c06000 /* jmp %g1+?; add lo 10 bits of value */
#define OPCODE_SAVE_SP64 0x9de3bfc0 /* save %sp, -64, %sp */


/* Return nonzero iff E_MACHINE is compatible with the running host.  */
static inline int
elf_machine_matches_host (Elf32_Half e_machine)
{
  switch (e_machine)
    {
    case EM_SPARC:
      return 1;
    default:
      return 0;
    }
}


/* 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 ("%l7");
  return *got;
}


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

/* The `subl' insn above will contain an R_68K_RELATIVE relocation
   entry intended to insert the run-time address of the label `here'.
   This will be the first relocation in the text of the dynamic
   linker; we skip it to avoid trying to modify read-only text in this
   early stage.  */
#define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) \
  ((dynamic_info)[DT_RELA]->d_un.d_ptr += sizeof (Elf32_Rela), \
   (dynamic_info)[DT_RELASZ]->d_un.d_val -= sizeof (Elf32_Rela))

/* 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,
		  Elf32_Addr (*resolve) (const Elf32_Sym **ref,
					 Elf32_Addr reloc_addr,
					 int noplt))
{
  Elf32_Addr *const reloc_addr = (void *) (map->l_addr + reloc->r_offset);
  Elf32_Addr loadbase;

  switch (ELF32_R_TYPE (reloc->r_info))
    {
    case R_SPARC_COPY:
      loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
      memcpy (reloc_addr, (void *) (loadbase + sym->st_value), sym->st_size);
      break;
    case R_SPARC_GLOB_DAT:
    case R_SPARC_32:
      loadbase = (resolve ? (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0) :
		  /* RESOLVE is null during bootstrap relocation.  */
		  map->l_addr);
      *reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
		     + reloc->r_addend);
      break;
    case R_SPARC_JMP_SLOT:
      loadbase = (resolve ? (*resolve) (&sym, (Elf32_Addr) reloc_addr, 1) :
		  /* RESOLVE is null during bootstrap relocation.  */
		  map->l_addr);
      {
	Elf32_Addr value = ((sym ? (loadbase + sym->st_value) : 0)
			    + reloc->r_addend);
	reloc_addr[1] = OPCODE_SETHI | (value >> 10);
	reloc_addr[2] = OPCODE_JMP_G1 | (value & 0x3ff);
      }
      break;
    case R_SPARC_8:
      loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
      *(char *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
			      + reloc->r_addend);
      break;
    case R_SPARC_16:
      loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
      *(short *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
			       + reloc->r_addend);
      break;
    case R_SPARC_32:
      loadbase = (resolve ? (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0) :
		  /* RESOLVE is null during bootstrap relocation.  */
		  map->l_addr);
      break;
    case R_SPARC_RELATIVE:
      *reloc_addr = map->l_addr + reloc->r_addend;
      break;
    case R_SPARC_DISP8:
      loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
      *(char *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
			      + reloc->r_addend
			      - (Elf32_Addr) reloc_addr);
      break;
    case R_SPARC_DISP16:
      loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
      *(short *) reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
			       + reloc->r_addend
			       - (Elf32_Addr) reloc_addr);
      break;
    case R_SPARC_DISP32:
      loadbase = (*resolve) (&sym, (Elf32_Addr) reloc_addr, 0);
      *reloc_addr = ((sym ? (loadbase + sym->st_value) : 0)
		     + reloc->r_addend
		     - (Elf32_Addr) reloc_addr);
      break;
    case R_SPARC_NONE:		/* Alright, Wilbur.  */
      break;
    default:
      assert (! "unexpected dynamic reloc type");
      break;
    }
}

static inline void
elf_machine_lazy_rel (struct link_map *map, const Elf32_Rela *reloc)
{
  switch (ELF32_R_TYPE (reloc->r_info))
    {
    case R_SPARC_NONE:
      break;
    case R_SPARC_JMP_SLOT:
      break;
    default:
      assert (! "unexpected PLT reloc type");
      break;
    }
}

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

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


/* 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 void
elf_machine_runtime_setup (struct link_map *l, int lazy)
{
  Elf32_Addr *plt;
  extern void _dl_runtime_resolve (Elf32_Word);

  if (l->l_info[DT_JMPREL] && lazy)
    {
      /* The entries for functions in the PLT have not yet been filled in.
	 Their initial contents will arrange when called to set the high 22
	 bits of %g1 with an offset into the .rela.plt section and jump to
	 the beginning of the PLT.  */
      plt = (Elf32_Addr *) (l->l_addr + l->l_info[DT_PLTGOT]->d_un.d_ptr);

      /* The beginning of the PLT does:

	 	save %sp, -64, %sp
	 pltpc:	call _dl_runtime_resolve
		nop
		.word MAP

         This saves the register window containing the arguments, and the
	 PC value (pltpc) implicitly saved in %o7 by the call points near the
	 location where we store the link_map pointer for this object.  */

      plt[0] = OPCODE_SAVE_SP64; /* save %sp, -64, %sp */
      /* Construct PC-relative word address.  */
      plt[1] = OPCODE_CALL | (((Elf32_Addr) &_dl_runtime_resolve -
			       (Elf32_Addr) &plt[1]) >> 2);
      plt[2] = OPCODE_NOP;	/* Fill call delay slot.  */
      plt[3] = l;
    }

  /* This code is used in dl-runtime.c to call the `fixup' function
     and then redirect to the address it returns.  */
#define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\
| Trampoline for _dl_runtime_resolver
	.globl _dl_runtime_resolve
	.type _dl_runtime_resolve, @function
_dl_runtime_resolve:
	| Pass two args to fixup: the PLT address computed from the PC saved
	| in the PLT's call insn, and the reloc offset passed in %g1.
	ld [%o7 + 8], %o1	| Second arg, loaded from PLTPC[2].
	call fixup
	shrl %g1, 22, %o0	| First arg, set in delay slot of call.
	| Jump to the real function.
	jmpl %o0, %g0
	| In the delay slot of that jump, restore the register window
	| saved by the first insn of the PLT.
	restore
	.size _dl_runtime_resolve, . - _dl_runtime_resolve
");
/* The PLT uses Elf32_Rela relocs.  */
#define elf_machine_relplt elf_machine_rela
}


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

/* 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 (???)