about summary refs log tree commit diff
path: root/sysdeps/generic/dl-tls.c
blob: 2c5fa75b62aeb511477d74ca72f82f9855c77522 (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
/* Thread-local storage handling in the ELF dynamic linker.  Generic version.
   Copyright (C) 2002 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 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.  */

#include <assert.h>
#include <stdlib.h>

#include <tls.h>

/* We don't need any of this if TLS is not supported.  */
#ifdef USE_TLS

#include <dl-tls.h>
#include <ldsodefs.h>

/* Value used for dtv entries for which the allocation is delayed.  */
# define TLS_DTV_UNALLOCATE	((void *) -1l)


size_t
internal_function
_dl_next_tls_modid (void)
{
  size_t result;

  if (__builtin_expect (GL(dl_tls_dtv_gaps), false))
    {
      /* XXX If this method proves too costly we can optimize
	 it to use a constant time method.  But I don't think
	 it's a problem.  */
      struct link_map *runp = GL(dl_initimage_list);
      bool used[GL(dl_tls_max_dtv_idx)];

      assert (runp != NULL);
      do
	{
	  assert (runp->l_tls_modid > 0
		  && runp->l_tls_modid <= GL(dl_tls_max_dtv_idx));
	  used[runp->l_tls_modid - 1] = true;
	}
      while ((runp = runp->l_tls_nextimage) != GL(dl_initimage_list));

      result = 0;
      do
	/* The information about the gaps is pessimistic.  It might be
	   there are actually none.  */
	if (result >= GL(dl_tls_max_dtv_idx))
	  {
	    /* Now we know there is actually no gap.  Bump the maximum
	       ID number and remember that there are no gaps.  */
	    result = ++GL(dl_tls_max_dtv_idx);
	    GL(dl_tls_dtv_gaps) = false;
	    break;
	  }
      while (used[result++]);
    }
  else
    /* No gaps, allocate a new entry.  */
    result = ++GL(dl_tls_max_dtv_idx);

  return result;
}


void
internal_function
_dl_determine_tlsoffset (struct link_map *firstp)
{
  struct link_map *runp = firstp;
  size_t max_align = 0;
  size_t offset;

  if (GL(dl_initimage_list) == NULL)
    {
      /* None of the objects used at startup time uses TLS.  We still
	 have to allocate the TCB adn dtv.  */
      GL(dl_tls_static_size) = TLS_TCB_SIZE;
      GL(dl_tls_static_align) = TLS_TCB_ALIGN;

      return;
    }

# if TLS_TCB_AT_TP
  /* We simply start with zero.  */
  offset = 0;

  do
    {
      max_align = MAX (max_align, runp->l_tls_align);

      /* Compute the offset of the next TLS block.  */
      offset = roundup (offset + runp->l_tls_blocksize, runp->l_tls_align);

      /* XXX For some architectures we perhaps should store the
	 negative offset.  */
      runp->l_tls_offset = offset;
    }
  while ((runp = runp->l_tls_nextimage) != firstp);

#if 0
  /* The thread descriptor (pointed to by the thread pointer) has its
     own alignment requirement.  Adjust the static TLS size
     and TLS offsets appropriately.  */
  // XXX How to deal with this.  We cannot simply add zero bytes
  // XXX after the first (closest to the TCB) TLS block since this
  // XXX would invalidate the offsets the linker creates for the LE
  // XXX model.
  if (offset % TLS_TCB_ALIGN != 0)
    abort ();
#endif

  GL(dl_tls_static_size) = offset + TLS_TCB_SIZE;
# elif TLS_DTV_AT_TP
  struct link_map *lastp;

  /* The first block starts right after the TCB.  */
  offset = TLS_TCB_SIZE;
  max_align = runp->l_tls_align;
  runp->l_tls_offset = offset;
  lastp = runp;

  while ((runp = runp->l_tls_nextimage) != firstp)
    {
      max_align = MAX (max_align, runp->l_tls_align);

      /* Compute the offset of the next TLS block.  */
      offset = roundup (offset + lastp->l_tls_blocksize, runp->l_tls_align);

      runp->l_tls_offset = offset;

      lastp = runp;
    }

  GL(dl_tls_static_size) = offset + lastp->l_tls_blocksize;
# else
#  error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
# endif

  /* The alignment requirement for the static TLS block.  */
  GL(dl_tls_static_align) = MAX (TLS_TCB_ALIGN, max_align);
}


void *
internal_function
_dl_allocate_tls (void)
{
  void *result;
  dtv_t *dtv;

  /* Allocate a correctly aligned chunk of memory.  */
  /* XXX For now */
  assert (GL(dl_tls_static_align) <= GL(dl_pagesize));
#ifdef MAP_ANON
# define _dl_zerofd (-1)
#else
# define _dl_zerofd GL(dl_zerofd)
  if ((dl_zerofd) == -1)
    GL(dl_zerofd) = _dl_sysdep_open_zero_fill ();
# define MAP_ANON 0
#endif
  result = __mmap (0, GL(dl_tls_static_size), PROT_READ|PROT_WRITE,
		   MAP_ANON|MAP_PRIVATE, _dl_zerofd, 0);

  dtv = (dtv_t *) malloc ((GL(dl_tls_max_dtv_idx) + 1) * sizeof (dtv_t));
  if (result != MAP_FAILED && dtv != NULL)
    {
      struct link_map *runp;

# if TLS_TCB_AT_TP
      /* The TCB follows the TLS blocks.  */
      result = (char *) result + GL(dl_tls_static_size) - TLS_TCB_SIZE;
# endif

      /* XXX Fill in an correct generation number.  */
      dtv[0].counter = 0;

      /* Initialize the memory from the initialization image list and clear
	 the BSS parts.  */
      if (GL(dl_initimage_list) != NULL)
	{
	  runp = GL(dl_initimage_list)->l_tls_nextimage;
	  do
	    {
	      assert (runp->l_tls_modid > 0);
	      assert (runp->l_tls_modid <= GL(dl_tls_max_dtv_idx));
# if TLS_TCB_AT_TP
	      dtv[runp->l_tls_modid].pointer = result - runp->l_tls_offset;
# elif TLS_DTV_AT_TP
	      dtv[runp->l_tls_modid].pointer = result + runp->l_tls_offset;
# else
#  error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
# endif

	      memset (__mempcpy (dtv[runp->l_tls_modid].pointer,
				 runp->l_tls_initimage,
				 runp->l_tls_initimage_size),
		      '\0',
		      runp->l_tls_blocksize - runp->l_tls_initimage_size);
	    }
	  while ((runp = runp->l_tls_nextimage)
		 !=  GL(dl_initimage_list)->l_tls_nextimage);
	}

      /* Add the dtv to the thread data structures.  */
      INSTALL_DTV (result, dtv);
    }
  else if (result != NULL)
    {
      free (result);
      result = NULL;
    }

  return result;
}


/* The __tls_get_addr function has two basic forms which differ in the
   arguments.  The IA-64 form takes two parameters, the module ID and
   offset.  The form used, among others, on IA-32 takes a reference to
   a special structure which contain the same information.  The second
   form seems to be more often used (in the moment) so we default to
   it.  Users of the IA-64 form have to provide adequate definitions
   of the following macros.  */
# ifndef GET_ADDR_ARGS
#  define GET_ADDR_ARGS tls_index *ti
# endif
# ifndef GET_ADDR_MODULE
#  define GET_ADDR_MODULE ti->ti_module
# endif
# ifndef GET_ADDR_OFFSET
#  define GET_ADDR_OFFSET ti->ti_offset
# endif


void *
__tls_get_addr (GET_ADDR_ARGS)
{
  dtv_t *dtv = THREAD_DTV ();

  if (dtv[GET_ADDR_MODULE].pointer == TLS_DTV_UNALLOCATE)
    /* XXX */;

  return (char *) dtv[GET_ADDR_MODULE].pointer + GET_ADDR_OFFSET;
}

#endif	/* use TLS */