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Diffstat (limited to 'src/linker/bionic_tls.h')
-rw-r--r-- | src/linker/bionic_tls.h | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/src/linker/bionic_tls.h b/src/linker/bionic_tls.h new file mode 100644 index 0000000..3907a83 --- /dev/null +++ b/src/linker/bionic_tls.h @@ -0,0 +1,141 @@ +/* + * 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. + */ +#ifndef _SYS_TLS_H +#define _SYS_TLS_H + +#define HAVE_ARM_TLS_REGISTER + +#include <sys/cdefs.h> + +__BEGIN_DECLS + +/** WARNING WARNING WARNING + ** + ** This header file is *NOT* part of the public Bionic ABI/API + ** and should not be used/included by user-serviceable parts of + ** the system (e.g. applications). + ** + ** It is only provided here for the benefit of the system dynamic + ** linker and the OpenGL sub-system (which needs to access the + ** pre-allocated slot directly for performance reason). + **/ + +/* maximum number of elements in the TLS array */ +#define BIONIC_TLS_SLOTS 64 + +/* note that slot 0, called TLS_SLOT_SELF must point to itself. + * this is required to implement thread-local storage with the x86 + * Linux kernel, that reads the TLS from fs:[0], where 'fs' is a + * thread-specific segment descriptor... + */ + +/* Well known TLS slots */ +#define TLS_SLOT_SELF 0 +#define TLS_SLOT_THREAD_ID 1 +#define TLS_SLOT_ERRNO 2 + +#define TLS_SLOT_OPENGL_API 3 +#define TLS_SLOT_OPENGL 4 + +/* this slot is only used to pass information from the dynamic linker to + * libc.so when the C library is loaded in to memory. The C runtime init + * function will then clear it. Since its use is extremely temporary, + * we reuse an existing location. + */ +#define TLS_SLOT_BIONIC_PREINIT (TLS_SLOT_ERRNO+1) + +/* small technical note: it is not possible to call pthread_setspecific + * on keys that are <= TLS_SLOT_MAX_WELL_KNOWN, which is why it is set to + * TLS_SLOT_ERRNO. + * + * later slots like TLS_SLOT_OPENGL are pre-allocated through the use of + * TLS_DEFAULT_ALLOC_MAP. this means that there is no need to use + * pthread_key_create() to initialize them. on the other hand, there is + * no destructor associated to them (we might need to implement this later) + */ +#define TLS_SLOT_MAX_WELL_KNOWN TLS_SLOT_ERRNO + +#define TLS_DEFAULT_ALLOC_MAP 0x0000001F + +/* set the Thread Local Storage, must contain at least BIONIC_TLS_SLOTS pointers */ +extern void __init_tls(void** tls, void* thread_info); + +/* syscall only, do not call directly */ +extern int __set_tls(void *ptr); + +/* get the TLS */ +#ifdef __arm__ +/* The standard way to get the TLS is to call a kernel helper + * function (i.e. a function provided at a fixed address in a + * "magic page" mapped in all user-space address spaces ), which + * contains the most appropriate code path for the target device. + * + * However, for performance reasons, we're going to use our own + * machine code for the system's C shared library. + * + * We cannot use this optimization in the static version of the + * C library, because we don't know where the corresponding code + * is going to run. + */ +# ifdef LIBC_STATIC + +/* Use the kernel helper in static C library. */ + typedef volatile void* (__kernel_get_tls_t)(void); +# define __get_tls() (*(__kernel_get_tls_t *)0xffff0fe0)() + +# else /* !LIBC_STATIC */ +/* Use optimized code path. + * Note that HAVE_ARM_TLS_REGISTER is build-specific + * (it must match your kernel configuration) + */ +# ifdef HAVE_ARM_TLS_REGISTER + /* We can read the address directly from a coprocessor + * register, which avoids touching the data cache + * completely. + */ +# define __get_tls() \ + ({ register unsigned int __val asm("r0"); \ + asm ("mrc p15, 0, r0, c13, c0, 3" : "=r"(__val) ); \ + (volatile void*)__val; }) +# else /* !HAVE_ARM_TLS_REGISTER */ + /* The kernel provides the address of the TLS at a fixed + * address of the magic page too. + */ +# define __get_tls() ( *((volatile void **) 0xffff0ff0) ) +# endif +# endif /* !LIBC_STATIC */ +#else /* !ARM */ +extern void* __get_tls( void ); +#endif /* !ARM */ + +/* return the stack base and size, used by our malloc debugger */ +extern void* __get_stack_base(int *p_stack_size); + +__END_DECLS + +#endif /* _SYS_TLS_H */ |