[thirdparty/glibc.git] / csu / libc-tls.c

/* Initialization code for TLS in statically linked application.
   Copyright (C) 2002, 2003, 2004, 2005 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 <errno.h>
#include <ldsodefs.h>
#include <tls.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/param.h>


#ifdef SHARED
 #error makefile bug, this file is for static only
#endif

#ifdef USE_TLS
extern ElfW(Phdr) *_dl_phdr;
extern size_t _dl_phnum;


static dtv_t static_dtv[2 + TLS_SLOTINFO_SURPLUS];


static struct
{
  struct dtv_slotinfo_list si;
  /* The dtv_slotinfo_list data structure does not include the actual
     information since it is defined as an array of size zero.  We define
     here the necessary entries.  Note that it is not important whether
     there is padding or not since we will always access the information
     through the 'si' element.  */
  struct dtv_slotinfo info[2 + TLS_SLOTINFO_SURPLUS];
} static_slotinfo;

/* Fake link map for the application.  */
static struct link_map static_map;


/* Highest dtv index currently needed.  */
size_t _dl_tls_max_dtv_idx;
/* Flag signalling whether there are gaps in the module ID allocation.  */
bool _dl_tls_dtv_gaps;
/* Information about the dtv slots.  */
struct dtv_slotinfo_list *_dl_tls_dtv_slotinfo_list;
/* Number of modules in the static TLS block.  */
size_t _dl_tls_static_nelem;
/* Size of the static TLS block.  Giving this initialized value
   preallocates some surplus bytes in the static TLS area.  */
size_t _dl_tls_static_size = 2048;
/* Size actually allocated in the static TLS block.  */
size_t _dl_tls_static_used;
/* Alignment requirement of the static TLS block.  */
size_t _dl_tls_static_align;

/* Generation counter for the dtv.  */
size_t _dl_tls_generation;


/* Additional definitions needed by TLS initialization.  */
#ifdef TLS_INIT_HELPER
TLS_INIT_HELPER
#endif

static inline void
init_slotinfo (void)
{
  /* Create the slotinfo list.  */
  static_slotinfo.si.len = (((char *) (&static_slotinfo + 1)
			     - (char *) &static_slotinfo.si.slotinfo[0])
			    / sizeof static_slotinfo.si.slotinfo[0]);
  // static_slotinfo.si.next = NULL;	already zero

  /* The slotinfo list.  Will be extended by the code doing dynamic
     linking.  */
  GL(dl_tls_max_dtv_idx) = 1;
  GL(dl_tls_dtv_slotinfo_list) = &static_slotinfo.si;
}

static inline void
init_static_tls (size_t memsz, size_t align)
{
  /* That is the size of the TLS memory for this object.  The initialized
     value of _dl_tls_static_size is provided by dl-open.c to request some
     surplus that permits dynamic loading of modules with IE-model TLS.  */
  GL(dl_tls_static_size) = roundup (memsz + GL(dl_tls_static_size),
				    TLS_TCB_ALIGN);
  GL(dl_tls_static_used) = memsz;
  /* The alignment requirement for the static TLS block.  */
  GL(dl_tls_static_align) = align;
  /* Number of elements in the static TLS block.  */
  GL(dl_tls_static_nelem) = GL(dl_tls_max_dtv_idx);
}

void
__libc_setup_tls (size_t tcbsize, size_t tcbalign)
{
  void *tlsblock;
  size_t memsz = 0;
  size_t filesz = 0;
  void *initimage = NULL;
  size_t align = 0;
  size_t max_align = tcbalign;
  size_t tcb_offset;
  ElfW(Phdr) *phdr;

  /* Look through the TLS segment if there is any.  */
  if (_dl_phdr != NULL)
    for (phdr = _dl_phdr; phdr < &_dl_phdr[_dl_phnum]; ++phdr)
      if (phdr->p_type == PT_TLS)
	{
	  /* Remember the values we need.  */
	  memsz = phdr->p_memsz;
	  filesz = phdr->p_filesz;
	  initimage = (void *) phdr->p_vaddr;
	  align = phdr->p_align;
	  if (phdr->p_align > max_align)
	    max_align = phdr->p_align;
	  break;
	}

  /* We have to set up the TCB block which also (possibly) contains
     'errno'.  Therefore we avoid 'malloc' which might touch 'errno'.
     Instead we use 'sbrk' which would only uses 'errno' if it fails.
     In this case we are right away out of memory and the user gets
     what she/he deserves.

     The initialized value of _dl_tls_static_size is provided by dl-open.c
     to request some surplus that permits dynamic loading of modules with
     IE-model TLS.  */
# if TLS_TCB_AT_TP
  tcb_offset = roundup (memsz + GL(dl_tls_static_size), tcbalign);
  tlsblock = __sbrk (tcb_offset + tcbsize + max_align);
# elif TLS_DTV_AT_TP
  tcb_offset = roundup (tcbsize, align ?: 1);
  tlsblock = __sbrk (tcb_offset + memsz + max_align
		     + TLS_PRE_TCB_SIZE + GL(dl_tls_static_size));
  tlsblock += TLS_PRE_TCB_SIZE;
# else
  /* In case a model with a different layout for the TCB and DTV
     is defined add another #elif here and in the following #ifs.  */
#  error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
# endif

  /* Align the TLS block.  */
  tlsblock = (void *) (((uintptr_t) tlsblock + max_align - 1)
		       & ~(max_align - 1));

  /* Initialize the dtv.  [0] is the length, [1] the generation counter.  */
  static_dtv[0].counter = (sizeof (static_dtv) / sizeof (static_dtv[0])) - 2;
  // static_dtv[1].counter = 0;		would be needed if not already done

  /* Initialize the TLS block.  */
# if TLS_TCB_AT_TP
  static_dtv[2].pointer.val = ((char *) tlsblock + tcb_offset
			       - roundup (memsz, align ?: 1));
  static_map.l_tls_offset = roundup (memsz, align ?: 1);
# elif TLS_DTV_AT_TP
  static_dtv[2].pointer.val = (char *) tlsblock + tcb_offset;
  static_map.l_tls_offset = tcb_offset;
# else
#  error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
# endif
  static_dtv[2].pointer.is_static = true;
  /* sbrk gives us zero'd memory, so we don't need to clear the remainder.  */
  memcpy (static_dtv[2].pointer.val, initimage, filesz);

  /* Install the pointer to the dtv.  */

  /* Initialize the thread pointer.  */
# if TLS_TCB_AT_TP
  INSTALL_DTV ((char *) tlsblock + tcb_offset, static_dtv);

  const char *lossage = TLS_INIT_TP ((char *) tlsblock + tcb_offset, 0);
# elif TLS_DTV_AT_TP
  INSTALL_DTV (tlsblock, static_dtv);
  const char *lossage = TLS_INIT_TP (tlsblock, 0);
# else
#  error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
# endif
  if (__builtin_expect (lossage != NULL, 0))
    __libc_fatal (lossage);

  /* We have to create a fake link map which normally would be created
     by the dynamic linker.  It just has to have enough information to
     make the TLS routines happy.  */
  static_map.l_tls_align = align;
  static_map.l_tls_blocksize = memsz;
  static_map.l_tls_initimage = initimage;
  static_map.l_tls_initimage_size = filesz;
  static_map.l_type = lt_executable;
  static_map.l_tls_modid = 1;

  init_slotinfo ();
  // static_slotinfo.si.slotinfo[1].gen = 0; already zero
  static_slotinfo.si.slotinfo[1].map = &static_map;

  memsz = roundup (memsz, align ?: 1);

# if TLS_TCB_AT_TP
  memsz += tcbsize;
# elif TLS_DTV_AT_TP
  memsz += tcb_offset;
# endif

  init_static_tls (memsz, MAX (TLS_TCB_ALIGN, max_align));
}

/* This is called only when the data structure setup was skipped at startup,
   when there was no need for it then.  Now we have dynamically loaded
   something needing TLS, or libpthread needs it.  */
int
internal_function
_dl_tls_setup (void)
{
  init_slotinfo ();
  init_static_tls (
# if TLS_TCB_AT_TP
		   TLS_TCB_SIZE,
# else
		   0,
# endif
		   TLS_TCB_ALIGN);
  return 0;
}


/* This is the minimal initialization function used when libpthread is
   not used.  */
void
__attribute__ ((weak))
__pthread_initialize_minimal (void)
{
  __libc_setup_tls (TLS_INIT_TCB_SIZE, TLS_INIT_TCB_ALIGN);
}

#elif defined NONTLS_INIT_TP

/* This is the minimal initialization function used when libpthread is
   not used.  */
void
__attribute__ ((weak))
__pthread_initialize_minimal (void)
{
  NONTLS_INIT_TP;
}

#endif
Commit	Line	Data
8a30f00f	1	/* Initialization code for TLS in statically linked application.
0ecb606c	2	Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
8a30f00f UD	3	This file is part of the GNU C Library.
	4
	5	The GNU C Library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
	9
	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Lesser General Public License for more details.
	14
	15	You should have received a copy of the GNU Lesser General Public
	16	License along with the GNU C Library; if not, write to the Free
	17	Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
	18	02111-1307 USA. */
	19
7d0b1164	20	#include <errno.h>
8a30f00f UD	21	#include <ldsodefs.h>
	22	#include <tls.h>
	23	#include <unistd.h>
82412d54	24	#include <stdio.h>
99343c05	25	#include <sys/param.h>
8a30f00f	26
82412d54	27
b9cb349f RM	28	#ifdef SHARED
	29	#error makefile bug, this file is for static only
	30	#endif
8a30f00f UD	31
	32	#ifdef USE_TLS
	33	extern ElfW(Phdr) *_dl_phdr;
	34	extern size_t _dl_phnum;
	35
	36
0ecb606c	37	static dtv_t static_dtv[2 + TLS_SLOTINFO_SURPLUS];
8a30f00f UD	38
	39
	40	static struct
	41	{
	42	struct dtv_slotinfo_list si;
	43	/* The dtv_slotinfo_list data structure does not include the actual
8265947d RM	44	information since it is defined as an array of size zero. We define
	45	here the necessary entries. Note that it is not important whether
	46	there is padding or not since we will always access the information
	47	through the 'si' element. */
8a30f00f UD	48	struct dtv_slotinfo info[2 + TLS_SLOTINFO_SURPLUS];
	49	} static_slotinfo;
	50
	51	/* Fake link map for the application. */
	52	static struct link_map static_map;
	53
	54
b9cb349f RM	55	/* Highest dtv index currently needed. */
	56	size_t _dl_tls_max_dtv_idx;
	57	/* Flag signalling whether there are gaps in the module ID allocation. */
	58	bool _dl_tls_dtv_gaps;
	59	/* Information about the dtv slots. */
	60	struct dtv_slotinfo_list *_dl_tls_dtv_slotinfo_list;
	61	/* Number of modules in the static TLS block. */
	62	size_t _dl_tls_static_nelem;
0ecb606c JJ	63	/* Size of the static TLS block. Giving this initialized value
	64	preallocates some surplus bytes in the static TLS area. */
	65	size_t _dl_tls_static_size = 2048;
80f6f981 UD	66	/* Size actually allocated in the static TLS block. */
80f6f981 UD	67	size_t _dl_tls_static_used;
b9cb349f RM	68	/* Alignment requirement of the static TLS block. */
	69	size_t _dl_tls_static_align;
	70
	71	/* Generation counter for the dtv. */
	72	size_t _dl_tls_generation;
	73
	74
2a76f7ef UD	75	/* Additional definitions needed by TLS initialization. */
	76	#ifdef TLS_INIT_HELPER
	77	TLS_INIT_HELPER
	78	#endif
	79
216455bc RM	80	static inline void
	81	init_slotinfo (void)
	82	{
	83	/* Create the slotinfo list. */
	84	static_slotinfo.si.len = (((char *) (&static_slotinfo + 1)
	85	- (char *) &static_slotinfo.si.slotinfo[0])
	86	/ sizeof static_slotinfo.si.slotinfo[0]);
	87	// static_slotinfo.si.next = NULL; already zero
	88
	89	/* The slotinfo list. Will be extended by the code doing dynamic
	90	linking. */
	91	GL(dl_tls_max_dtv_idx) = 1;
	92	GL(dl_tls_dtv_slotinfo_list) = &static_slotinfo.si;
	93	}
	94
	95	static inline void
	96	init_static_tls (size_t memsz, size_t align)
	97	{
	98	/* That is the size of the TLS memory for this object. The initialized
	99	value of _dl_tls_static_size is provided by dl-open.c to request some
	100	surplus that permits dynamic loading of modules with IE-model TLS. */
	101	GL(dl_tls_static_size) = roundup (memsz + GL(dl_tls_static_size),
	102	TLS_TCB_ALIGN);
	103	GL(dl_tls_static_used) = memsz;
	104	/* The alignment requirement for the static TLS block. */
	105	GL(dl_tls_static_align) = align;
	106	/* Number of elements in the static TLS block. */
	107	GL(dl_tls_static_nelem) = GL(dl_tls_max_dtv_idx);
	108	}
2a76f7ef	109
8a30f00f UD	110	void
	111	__libc_setup_tls (size_t tcbsize, size_t tcbalign)
	112	{
	113	void *tlsblock;
	114	size_t memsz = 0;
	115	size_t filesz = 0;
d10c6430	116	void *initimage = NULL;
8a30f00f UD	117	size_t align = 0;
8a30f00f UD	118	size_t max_align = tcbalign;
8a30f00f	119	size_t tcb_offset;
a162642d	120	ElfW(Phdr) *phdr;
8a30f00f UD	121
	122	/* Look through the TLS segment if there is any. */
	123	if (_dl_phdr != NULL)
a162642d	124	for (phdr = _dl_phdr; phdr < &_dl_phdr[_dl_phnum]; ++phdr)
d10c6430 RM	125	if (phdr->p_type == PT_TLS)
	126	{
	127	/* Remember the values we need. */
	128	memsz = phdr->p_memsz;
	129	filesz = phdr->p_filesz;
	130	initimage = (void *) phdr->p_vaddr;
	131	align = phdr->p_align;
	132	if (phdr->p_align > max_align)
	133	max_align = phdr->p_align;
	134	break;
	135	}
8a30f00f	136
8a30f00f UD	137	/* We have to set up the TCB block which also (possibly) contains
	138	'errno'. Therefore we avoid 'malloc' which might touch 'errno'.
	139	Instead we use 'sbrk' which would only uses 'errno' if it fails.
	140	In this case we are right away out of memory and the user gets
e7e6e437 RM	141	what she/he deserves.
	142
	143	The initialized value of _dl_tls_static_size is provided by dl-open.c
	144	to request some surplus that permits dynamic loading of modules with
	145	IE-model TLS. */
8a30f00f	146	# if TLS_TCB_AT_TP
216455bc RM	147	tcb_offset = roundup (memsz + GL(dl_tls_static_size), tcbalign);
216455bc RM	148	tlsblock = __sbrk (tcb_offset + tcbsize + max_align);
8a30f00f	149	# elif TLS_DTV_AT_TP
aff4519d UD	150	tcb_offset = roundup (tcbsize, align ?: 1);
	151	tlsblock = __sbrk (tcb_offset + memsz + max_align
	152	+ TLS_PRE_TCB_SIZE + GL(dl_tls_static_size));
	153	tlsblock += TLS_PRE_TCB_SIZE;
8a30f00f UD	154	# else
	155	/* In case a model with a different layout for the TCB and DTV
	156	is defined add another #elif here and in the following #ifs. */
	157	# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
	158	# endif
	159
	160	/* Align the TLS block. */
	161	tlsblock = (void *) (((uintptr_t) tlsblock + max_align - 1)
	162	& ~(max_align - 1));
	163
	164	/* Initialize the dtv. [0] is the length, [1] the generation counter. */
0ecb606c	165	static_dtv[0].counter = (sizeof (static_dtv) / sizeof (static_dtv[0])) - 2;
8a30f00f UD	166	// static_dtv[1].counter = 0; would be needed if not already done
	167
	168	/* Initialize the TLS block. */
	169	# if TLS_TCB_AT_TP
0ecb606c JJ	170	static_dtv[2].pointer.val = ((char *) tlsblock + tcb_offset
0ecb606c JJ	171	- roundup (memsz, align ?: 1));
82412d54	172	static_map.l_tls_offset = roundup (memsz, align ?: 1);
8a30f00f	173	# elif TLS_DTV_AT_TP
0ecb606c	174	static_dtv[2].pointer.val = (char *) tlsblock + tcb_offset;
216455bc	175	static_map.l_tls_offset = tcb_offset;
8a30f00f UD	176	# else
	177	# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
	178	# endif
0ecb606c	179	static_dtv[2].pointer.is_static = true;
82412d54	180	/* sbrk gives us zero'd memory, so we don't need to clear the remainder. */
0ecb606c	181	memcpy (static_dtv[2].pointer.val, initimage, filesz);
8a30f00f UD	182
	183	/* Install the pointer to the dtv. */
	184
	185	/* Initialize the thread pointer. */
	186	# if TLS_TCB_AT_TP
8a30f00f UD	187	INSTALL_DTV ((char *) tlsblock + tcb_offset, static_dtv);
8a30f00f UD	188
82412d54	189	const char lossage = TLS_INIT_TP ((char ) tlsblock + tcb_offset, 0);
8a30f00f UD	190	# elif TLS_DTV_AT_TP
8a30f00f UD	191	INSTALL_DTV (tlsblock, static_dtv);
82412d54	192	const char *lossage = TLS_INIT_TP (tlsblock, 0);
8a30f00f UD	193	# else
	194	# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
	195	# endif
82412d54 RM	196	if (__builtin_expect (lossage != NULL, 0))
82412d54 RM	197	__libc_fatal (lossage);
8a30f00f UD	198
8a30f00f UD	199	/* We have to create a fake link map which normally would be created
a816b435	200	by the dynamic linker. It just has to have enough information to
8a30f00f UD	201	make the TLS routines happy. */
	202	static_map.l_tls_align = align;
	203	static_map.l_tls_blocksize = memsz;
8265947d	204	static_map.l_tls_initimage = initimage;
8a30f00f	205	static_map.l_tls_initimage_size = filesz;
8a30f00f UD	206	static_map.l_type = lt_executable;
	207	static_map.l_tls_modid = 1;
	208
216455bc RM	209	init_slotinfo ();
216455bc RM	210	// static_slotinfo.si.slotinfo[1].gen = 0; already zero
8a30f00f UD	211	static_slotinfo.si.slotinfo[1].map = &static_map;
8a30f00f UD	212
c56baa87	213	memsz = roundup (memsz, align ?: 1);
216455bc	214
8a30f00f	215	# if TLS_TCB_AT_TP
c56baa87	216	memsz += tcbsize;
aff4519d UD	217	# elif TLS_DTV_AT_TP
aff4519d UD	218	memsz += tcb_offset;
f7c1f4dd	219	# endif
c56baa87	220
216455bc RM	221	init_static_tls (memsz, MAX (TLS_TCB_ALIGN, max_align));
	222	}
	223
	224	/* This is called only when the data structure setup was skipped at startup,
	225	when there was no need for it then. Now we have dynamically loaded
	226	something needing TLS, or libpthread needs it. */
	227	int
	228	internal_function
	229	_dl_tls_setup (void)
	230	{
	231	init_slotinfo ();
	232	init_static_tls (
	233	# if TLS_TCB_AT_TP
	234	TLS_TCB_SIZE,
	235	# else
	236	0,
	237	# endif
	238	TLS_TCB_ALIGN);
	239	return 0;
8a30f00f UD	240	}
	241
	242
	243	/* This is the minimal initialization function used when libpthread is
	244	not used. */
	245	void
	246	__attribute__ ((weak))
	247	__pthread_initialize_minimal (void)
	248	{
0f283ffc	249	__libc_setup_tls (TLS_INIT_TCB_SIZE, TLS_INIT_TCB_ALIGN);
8a30f00f	250	}
131fd126 UD	251
	252	#elif defined NONTLS_INIT_TP
	253
	254	/* This is the minimal initialization function used when libpthread is
	255	not used. */
	256	void
	257	__attribute__ ((weak))
	258	__pthread_initialize_minimal (void)
	259	{
	260	NONTLS_INIT_TP;
	261	}
	262
8a30f00f	263	#endif