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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <pthread.h>
struct user_desc {
unsigned int entry_number;
unsigned long base_addr;
unsigned int limit;
unsigned int seg_32bit:1;
unsigned int contents:2;
unsigned int read_exec_only:1;
unsigned int limit_in_pages:1;
unsigned int seg_not_present:1;
unsigned int useable:1;
unsigned int empty:25;
};
extern int __set_thread_area(struct user_desc *u_info);
/* the following can't be const, since the first call will
* update the 'entry_number' field
*/
static struct user_desc _tls_desc =
{
-1,
0,
0x1000,
1,
0,
0,
1,
0,
1,
0
};
struct _thread_area_head {
void *self;
};
/* we implement thread local storage through the gs: segment descriptor
* we create a segment descriptor for the tls
*/
int __set_tls(void *ptr)
{
int rc, segment;
_tls_desc.base_addr = (unsigned long)ptr;
/* We also need to write the location of the tls to ptr[0] */
((struct _thread_area_head *)ptr)->self = ptr;
rc = __set_thread_area( &_tls_desc );
if (rc != 0)
{
/* could not set thread local area */
return -1;
}
/* this weird computation comes from GLibc */
segment = _tls_desc.entry_number*8 + 3;
asm __volatile__ (
" movw %w0, %%gs" :: "q"(segment)
);
return 0;
}
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