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