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/* 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 <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 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);
/* The thread descriptor (pointed to by the thread pointer) has its
own alignment requirement. Adjust the static TLS size
and TLS offsets appropriately. */
if (offset % TLS_TCB_ALIGN != 0)
{
size_t add = TLS_TCB_ALIGN - offset % TLS_TCB_ALIGN;
/* XXX If the offset stored is negative we must subtract here. */
offset += add;
runp = firstp;
do
runp->l_tls_offset += add;
while ((runp = runp->l_tls_nextimage) != firstp);
}
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);
}
/* 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 */
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