this leads to much improved code when calling __get_tls() Change-Id: I21d870fb33c33a921ca55c4e100772e0f7a8d1e4
		
			
				
	
	
		
			118 lines
		
	
	
		
			4.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			118 lines
		
	
	
		
			4.3 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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#ifndef _SYS_TLS_H
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#define _SYS_TLS_H
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#include <sys/cdefs.h>
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__BEGIN_DECLS
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/** WARNING WARNING WARNING
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 **
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 ** This header file is *NOT* part of the public Bionic ABI/API
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 ** and should not be used/included by user-serviceable parts of
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 ** the system (e.g. applications).
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 **
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 ** It is only provided here for the benefit of the system dynamic
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 ** linker and the OpenGL sub-system (which needs to access the
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 ** pre-allocated slot directly for performance reason).
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 **/
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/* Well-known TLS slots. What data goes in which slot is arbitrary unless otherwise noted. */
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enum {
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  TLS_SLOT_SELF = 0, /* The kernel requires this specific slot for x86. */
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  TLS_SLOT_THREAD_ID,
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  TLS_SLOT_ERRNO,
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  /* These two aren't used by bionic itself, but allow the graphics code to
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   * access TLS directly rather than using the pthread API. */
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  TLS_SLOT_OPENGL_API = 3,
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  TLS_SLOT_OPENGL = 4,
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  /* This slot is only used to pass information from the dynamic linker to
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   * libc.so when the C library is loaded in to memory. The C runtime init
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   * function will then clear it. Since its use is extremely temporary,
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   * we reuse an existing location that isn't needed during libc startup. */
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  TLS_SLOT_BIONIC_PREINIT = TLS_SLOT_OPENGL_API,
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  TLS_SLOT_STACK_GUARD = 5, /* GCC requires this specific slot for x86. */
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  TLS_SLOT_DLERROR,
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  TLS_SLOT_FIRST_USER_SLOT /* Must come last! */
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};
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/*
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 * Maximum number of elements in the TLS array.
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 * POSIX says this must be at least 128, but Android has traditionally had only 64, minus those
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 * ones used internally by bionic itself.
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 * There are two kinds of slot used internally by bionic --- there are the well-known slots
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 * enumerated above, and then there are those that are allocated during startup by calls to
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 * pthread_key_create; grep for GLOBAL_INIT_THREAD_LOCAL_BUFFER to find those. We need to manually
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 * maintain that second number, but pthread_test will fail if we forget.
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 */
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#define GLOBAL_INIT_THREAD_LOCAL_BUFFER_COUNT 4
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#define BIONIC_TLS_SLOTS 64
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/* syscall only, do not call directly */
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extern int __set_tls(void* ptr);
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/* get the TLS */
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#if defined(__arm__)
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# define __get_tls() \
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    ({ register unsigned int __val; \
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       asm ("mrc p15, 0, %0, c13, c0, 3" : "=r"(__val)); \
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       (volatile void*) __val; })
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#elif defined(__mips__)
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# define __get_tls() \
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    ({ register unsigned int __val; \
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       asm ("   .set    push\n" \
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            "   .set    mips32r2\n" \
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            "   rdhwr   %0,$29\n" \
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            "   .set    pop\n" : "=r"(__val)); \
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       (volatile void*) __val; })
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#elif defined(__i386__)
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# define __get_tls() \
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    ({ register void* __val; \
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       asm ("movl %%gs:0, %0" : "=r"(__val)); \
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       (volatile void*) __val; })
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#else
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#error unsupported architecture
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#endif
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/* return the stack base and size, used by our malloc debugger */
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extern void* __get_stack_base(int* p_stack_size);
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__END_DECLS
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#if defined(__cplusplus)
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struct KernelArgumentBlock;
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extern __LIBC_HIDDEN__ void __libc_init_tls(KernelArgumentBlock& args);
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#endif
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#endif /* _SYS_TLS_H */
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