[thirdparty/glibc.git] / sysdeps / hppa / dl-fptr.c

/* Manage function descriptors.  Generic version.
   Copyright (C) 1999-2015 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 <libintl.h>
#include <unistd.h>
#include <string.h>
#include <sys/param.h>
#include <sys/mman.h>
#include <link.h>
#include <ldsodefs.h>
#include <elf/dynamic-link.h>
#include <dl-fptr.h>
#include <dl-unmap-segments.h>
#include <atomic.h>

#ifndef ELF_MACHINE_BOOT_FPTR_TABLE_LEN
/* ELF_MACHINE_BOOT_FPTR_TABLE_LEN should be greater than the number of
   dynamic symbols in ld.so.  */
# define ELF_MACHINE_BOOT_FPTR_TABLE_LEN 256
#endif

#ifndef ELF_MACHINE_LOAD_ADDRESS
# error "ELF_MACHINE_LOAD_ADDRESS is not defined."
#endif

#ifndef COMPARE_AND_SWAP
# define COMPARE_AND_SWAP(ptr, old, new) \
  (catomic_compare_and_exchange_bool_acq (ptr, new, old) == 0)
#endif

ElfW(Addr) _dl_boot_fptr_table [ELF_MACHINE_BOOT_FPTR_TABLE_LEN];

static struct local
  {
    struct fdesc_table *root;
    struct fdesc *free_list;
    unsigned int npages;		/* # of pages to allocate */
    /* the next to members MUST be consecutive! */
    struct fdesc_table boot_table;
    struct fdesc boot_fdescs[1024];
  }
local =
  {
#ifdef SHARED
    /* Address of .boot_table is not known until runtime.  */
    .root = 0,
#else
    .root = &local.boot_table,
#endif
    .npages = 2,
    .boot_table =
      {
	.len = sizeof (local.boot_fdescs) / sizeof (local.boot_fdescs[0]),
	.first_unused = 0
      }
  };

/* Create a new fdesc table and return a pointer to the first fdesc
   entry.  The fdesc lock must have been acquired already.  */

static struct fdesc_table *
new_fdesc_table (struct local *l, size_t *size)
{
  size_t old_npages = l->npages;
  size_t new_npages = old_npages + old_npages;
  struct fdesc_table *new_table;

  /* If someone has just created a new table, we return NULL to tell
     the caller to use the new table.  */
  if (! COMPARE_AND_SWAP (&l->npages, old_npages, new_npages))
    return (struct fdesc_table *) NULL;

  *size = old_npages * GLRO(dl_pagesize);
  new_table = __mmap (NULL, *size,
		      PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0);
  if (new_table == MAP_FAILED)
    _dl_signal_error (errno, NULL, NULL,
		      N_("cannot map pages for fdesc table"));

  new_table->len
    = (*size - sizeof (*new_table)) / sizeof (struct fdesc);
  new_table->first_unused = 1;
  return new_table;
}

/* Must call _dl_fptr_init before using any other function.  */
void
_dl_fptr_init (void)
{
  struct local *l;

  ELF_MACHINE_LOAD_ADDRESS (l, local);
  l->root = &l->boot_table;
}

static ElfW(Addr)
make_fdesc (ElfW(Addr) ip, ElfW(Addr) gp)
{
  struct fdesc *fdesc = NULL;
  struct fdesc_table *root;
  unsigned int old;
  struct local *l;

  ELF_MACHINE_LOAD_ADDRESS (l, local);

 retry:
  root = l->root;
  while (1)
    {
      old = root->first_unused;
      if (old >= root->len)
	break;
      else if (COMPARE_AND_SWAP (&root->first_unused, old, old + 1))
	{
	  fdesc = &root->fdesc[old];
	  goto install;
	}
    }

  if (l->free_list)
    {
      /* Get it from free-list.  */
      do
	{
	  fdesc = l->free_list;
	  if (fdesc == NULL)
	    goto retry;
	}
      while (! COMPARE_AND_SWAP ((ElfW(Addr) *) &l->free_list,
				 (ElfW(Addr)) fdesc, fdesc->ip));
    }
  else
    {
      /* Create a new fdesc table.  */
      size_t size;
      struct fdesc_table *new_table = new_fdesc_table (l, &size);

      if (new_table == NULL)
	goto retry;

      new_table->next = root;
      if (! COMPARE_AND_SWAP ((ElfW(Addr) *) &l->root,
			      (ElfW(Addr)) root,
			      (ElfW(Addr)) new_table))
	{
	  /* Someone has just installed a new table. Return NULL to
	     tell the caller to use the new table.  */
	  __munmap (new_table, size);
	  goto retry;
	}

      /* Note that the first entry was reserved while allocating the
	 memory for the new page.  */
      fdesc = &new_table->fdesc[0];
    }

 install:
  fdesc->ip = ip;
  fdesc->gp = gp;

  return (ElfW(Addr)) fdesc;
}


static inline ElfW(Addr) * __attribute__ ((always_inline))
make_fptr_table (struct link_map *map)
{
  const ElfW(Sym) *symtab
    = (const void *) D_PTR (map, l_info[DT_SYMTAB]);
  const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
  ElfW(Addr) *fptr_table;
  size_t size;
  size_t len;

  /* XXX Apparently the only way to find out the size of the dynamic
     symbol section is to assume that the string table follows right
     afterwards...  */
  len = ((strtab - (char *) symtab)
	 / map->l_info[DT_SYMENT]->d_un.d_val);
  size = ((len * sizeof (fptr_table[0]) + GLRO(dl_pagesize) - 1)
	  & -GLRO(dl_pagesize));
  /* XXX We don't support here in the moment systems without MAP_ANON.
     There probably are none for IA-64.  In case this is proven wrong
     we will have to open /dev/null here and use the file descriptor
     instead of the hard-coded -1.  */
  fptr_table = __mmap (NULL, size,
		       PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE,
		       -1, 0);
  if (fptr_table == MAP_FAILED)
    _dl_signal_error (errno, NULL, NULL,
		      N_("cannot map pages for fptr table"));

  if (COMPARE_AND_SWAP ((ElfW(Addr) *) &map->l_mach.fptr_table,
			(ElfW(Addr)) NULL, (ElfW(Addr)) fptr_table))
    map->l_mach.fptr_table_len = len;
  else
    __munmap (fptr_table, len * sizeof (fptr_table[0]));

  return map->l_mach.fptr_table;
}


ElfW(Addr)
_dl_make_fptr (struct link_map *map, const ElfW(Sym) *sym,
	       ElfW(Addr) ip)
{
  ElfW(Addr) *ftab = map->l_mach.fptr_table;
  const ElfW(Sym) *symtab;
  Elf_Symndx symidx;
  struct local *l;

  if (__builtin_expect (ftab == NULL, 0))
    ftab = make_fptr_table (map);

  symtab = (const void *) D_PTR (map, l_info[DT_SYMTAB]);
  symidx = sym - symtab;

  if (symidx >= map->l_mach.fptr_table_len)
    _dl_signal_error (0, NULL, NULL,
		      N_("internal error: symidx out of range of fptr table"));

  while (ftab[symidx] == 0)
    {
      /* GOT has already been relocated in elf_get_dynamic_info -
	 don't try to relocate it again.  */
      ElfW(Addr) fdesc
	= make_fdesc (ip, map->l_info[DT_PLTGOT]->d_un.d_ptr);

      if (__builtin_expect (COMPARE_AND_SWAP (&ftab[symidx], (ElfW(Addr)) NULL,
					      fdesc), 1))
	{
	  /* Noone has updated the entry and the new function
	     descriptor has been installed.  */
#if 0
	  const char *strtab
	    = (const void *) D_PTR (map, l_info[DT_STRTAB]);

	  ELF_MACHINE_LOAD_ADDRESS (l, local);
	  if (l->root != &l->boot_table
	      || l->boot_table.first_unused > 20)
	    _dl_debug_printf ("created fdesc symbol `%s' at %lx\n",
			      strtab + sym->st_name, ftab[symidx]);
#endif
	  break;
	}
      else
	{
	  /* We created a duplicated function descriptor. We put it on
	     free-list.  */
	  struct fdesc *f = (struct fdesc *) fdesc;

	  ELF_MACHINE_LOAD_ADDRESS (l, local);

	  do
	    f->ip = (ElfW(Addr)) l->free_list;
	  while (! COMPARE_AND_SWAP ((ElfW(Addr) *) &l->free_list,
				     f->ip, fdesc));
	}
    }

  return ftab[symidx];
}


void
_dl_unmap (struct link_map *map)
{
  ElfW(Addr) *ftab = map->l_mach.fptr_table;
  struct fdesc *head = NULL, *tail = NULL;
  size_t i;

  _dl_unmap_segments (map);

  if (ftab == NULL)
    return;

  /* String together the fdesc structures that are being freed.  */
  for (i = 0; i < map->l_mach.fptr_table_len; ++i)
    {
      if (ftab[i])
	{
	  *(struct fdesc **) ftab[i] = head;
	  head = (struct fdesc *) ftab[i];
	  if (tail == NULL)
	    tail = head;
	}
    }

  /* Prepend the new list to the free_list: */
  if (tail)
    do
      tail->ip = (ElfW(Addr)) local.free_list;
    while (! COMPARE_AND_SWAP ((ElfW(Addr) *) &local.free_list,
			       tail->ip, (ElfW(Addr)) head));

  __munmap (ftab, (map->l_mach.fptr_table_len
		   * sizeof (map->l_mach.fptr_table[0])));

  map->l_mach.fptr_table = NULL;
}


ElfW(Addr)
_dl_lookup_address (const void *address)
{
  ElfW(Addr) addr = (ElfW(Addr)) address;
  struct fdesc_table *t;
  unsigned long int i;

  for (t = local.root; t != NULL; t = t->next)
    {
      i = (struct fdesc *) addr - &t->fdesc[0];
      if (i < t->first_unused && addr == (ElfW(Addr)) &t->fdesc[i])
	{
	  addr = t->fdesc[i].ip;
	  break;
	}
    }

  return addr;
}
Commit	Line	Data
dde6fc78	1	/* Manage function descriptors. Generic version.
b168057a	2	Copyright (C) 1999-2015 Free Software Foundation, Inc.
dde6fc78 CD	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
	20	#include <libintl.h>
	21	#include <unistd.h>
	22	#include <string.h>
	23	#include <sys/param.h>
	24	#include <sys/mman.h>
	25	#include <link.h>
	26	#include <ldsodefs.h>
	27	#include <elf/dynamic-link.h>
	28	#include <dl-fptr.h>
fcccd512	29	#include <dl-unmap-segments.h>
dde6fc78 CD	30	#include <atomic.h>
	31
	32	#ifndef ELF_MACHINE_BOOT_FPTR_TABLE_LEN
	33	/* ELF_MACHINE_BOOT_FPTR_TABLE_LEN should be greater than the number of
	34	dynamic symbols in ld.so. */
	35	# define ELF_MACHINE_BOOT_FPTR_TABLE_LEN 256
	36	#endif
	37
	38	#ifndef ELF_MACHINE_LOAD_ADDRESS
	39	# error "ELF_MACHINE_LOAD_ADDRESS is not defined."
	40	#endif
	41
	42	#ifndef COMPARE_AND_SWAP
	43	# define COMPARE_AND_SWAP(ptr, old, new) \
	44	(catomic_compare_and_exchange_bool_acq (ptr, new, old) == 0)
	45	#endif
	46
	47	ElfW(Addr) _dl_boot_fptr_table [ELF_MACHINE_BOOT_FPTR_TABLE_LEN];
	48
	49	static struct local
	50	{
	51	struct fdesc_table *root;
	52	struct fdesc *free_list;
	53	unsigned int npages; /* # of pages to allocate */
	54	/* the next to members MUST be consecutive! */
	55	struct fdesc_table boot_table;
	56	struct fdesc boot_fdescs[1024];
	57	}
	58	local =
	59	{
	60	#ifdef SHARED
	61	/* Address of .boot_table is not known until runtime. */
	62	.root = 0,
	63	#else
	64	.root = &local.boot_table,
	65	#endif
	66	.npages = 2,
	67	.boot_table =
	68	{
	69	.len = sizeof (local.boot_fdescs) / sizeof (local.boot_fdescs[0]),
	70	.first_unused = 0
	71	}
	72	};
	73
	74	/* Create a new fdesc table and return a pointer to the first fdesc
	75	entry. The fdesc lock must have been acquired already. */
	76
	77	static struct fdesc_table *
	78	new_fdesc_table (struct local l, size_t size)
	79	{
	80	size_t old_npages = l->npages;
	81	size_t new_npages = old_npages + old_npages;
	82	struct fdesc_table *new_table;
	83
	84	/* If someone has just created a new table, we return NULL to tell
	85	the caller to use the new table. */
	86	if (! COMPARE_AND_SWAP (&l->npages, old_npages, new_npages))
	87	return (struct fdesc_table *) NULL;
	88
	89	size = old_npages GLRO(dl_pagesize);
	90	new_table = __mmap (NULL, *size,
	91	PROT_READ \| PROT_WRITE, MAP_ANON \| MAP_PRIVATE, -1, 0);
	92	if (new_table == MAP_FAILED)
	93	_dl_signal_error (errno, NULL, NULL,
94	N_("cannot map pages for fdesc table"));
95
96	new_table->len
97	= (size - sizeof (new_table)) / sizeof (struct fdesc);
98	new_table->first_unused = 1;
99	return new_table;
100	}
101
102	/* Must call _dl_fptr_init before using any other function. */
5556231d	103	void
dde6fc78 CD	104	_dl_fptr_init (void)
	105	{
	106	struct local *l;
	107
	108	ELF_MACHINE_LOAD_ADDRESS (l, local);
	109	l->root = &l->boot_table;
	110	}
	111
	112	static ElfW(Addr)
	113	make_fdesc (ElfW(Addr) ip, ElfW(Addr) gp)
	114	{
	115	struct fdesc *fdesc = NULL;
	116	struct fdesc_table *root;
	117	unsigned int old;
	118	struct local *l;
	119
	120	ELF_MACHINE_LOAD_ADDRESS (l, local);
	121
	122	retry:
	123	root = l->root;
	124	while (1)
	125	{
	126	old = root->first_unused;
	127	if (old >= root->len)
	128	break;
	129	else if (COMPARE_AND_SWAP (&root->first_unused, old, old + 1))
	130	{
	131	fdesc = &root->fdesc[old];
	132	goto install;
	133	}
	134	}
	135
	136	if (l->free_list)
	137	{
	138	/* Get it from free-list. */
	139	do
	140	{
	141	fdesc = l->free_list;
	142	if (fdesc == NULL)
	143	goto retry;
	144	}
	145	while (! COMPARE_AND_SWAP ((ElfW(Addr) *) &l->free_list,
	146	(ElfW(Addr)) fdesc, fdesc->ip));
	147	}
	148	else
	149	{
	150	/* Create a new fdesc table. */
	151	size_t size;
	152	struct fdesc_table *new_table = new_fdesc_table (l, &size);
	153
	154	if (new_table == NULL)
	155	goto retry;
	156
	157	new_table->next = root;
	158	if (! COMPARE_AND_SWAP ((ElfW(Addr) *) &l->root,
	159	(ElfW(Addr)) root,
	160	(ElfW(Addr)) new_table))
	161	{
	162	/* Someone has just installed a new table. Return NULL to
	163	tell the caller to use the new table. */
	164	__munmap (new_table, size);
	165	goto retry;
	166	}
	167
168	/* Note that the first entry was reserved while allocating the
169	memory for the new page. */
170	fdesc = &new_table->fdesc[0];
171	}
172
173	install:
174	fdesc->ip = ip;
175	fdesc->gp = gp;
176
177	return (ElfW(Addr)) fdesc;
178	}
179
180
181	static inline ElfW(Addr) * __attribute__ ((always_inline))
182	make_fptr_table (struct link_map *map)
183	{
184	const ElfW(Sym) *symtab
185	= (const void *) D_PTR (map, l_info[DT_SYMTAB]);
186	const char strtab = (const void ) D_PTR (map, l_info[DT_STRTAB]);
187	ElfW(Addr) *fptr_table;
188	size_t size;
189	size_t len;
190
191	/* XXX Apparently the only way to find out the size of the dynamic
192	symbol section is to assume that the string table follows right
193	afterwards... */
194	len = ((strtab - (char *) symtab)
195	/ map->l_info[DT_SYMENT]->d_un.d_val);
196	size = ((len * sizeof (fptr_table[0]) + GLRO(dl_pagesize) - 1)
197	& -GLRO(dl_pagesize));
198	/* XXX We don't support here in the moment systems without MAP_ANON.
199	There probably are none for IA-64. In case this is proven wrong
200	we will have to open /dev/null here and use the file descriptor
201	instead of the hard-coded -1. */
202	fptr_table = __mmap (NULL, size,
203	PROT_READ \| PROT_WRITE, MAP_ANON \| MAP_PRIVATE,
204	-1, 0);
205	if (fptr_table == MAP_FAILED)
206	_dl_signal_error (errno, NULL, NULL,
207	N_("cannot map pages for fptr table"));
208
209	if (COMPARE_AND_SWAP ((ElfW(Addr) *) &map->l_mach.fptr_table,
210	(ElfW(Addr)) NULL, (ElfW(Addr)) fptr_table))
211	map->l_mach.fptr_table_len = len;
212	else
213	__munmap (fptr_table, len * sizeof (fptr_table[0]));
214
215	return map->l_mach.fptr_table;
216	}
217
218
219	ElfW(Addr)
220	_dl_make_fptr (struct link_map map, const ElfW(Sym) sym,
221	ElfW(Addr) ip)
222	{
223	ElfW(Addr) *ftab = map->l_mach.fptr_table;
224	const ElfW(Sym) *symtab;
225	Elf_Symndx symidx;
226	struct local *l;
227
228	if (__builtin_expect (ftab == NULL, 0))
229	ftab = make_fptr_table (map);
230
231	symtab = (const void *) D_PTR (map, l_info[DT_SYMTAB]);
232	symidx = sym - symtab;
233
234	if (symidx >= map->l_mach.fptr_table_len)
235	_dl_signal_error (0, NULL, NULL,
236	N_("internal error: symidx out of range of fptr table"));
237
238	while (ftab[symidx] == 0)
239	{
240	/* GOT has already been relocated in elf_get_dynamic_info -
241	don't try to relocate it again. */
242	ElfW(Addr) fdesc
243	= make_fdesc (ip, map->l_info[DT_PLTGOT]->d_un.d_ptr);
244
245	if (__builtin_expect (COMPARE_AND_SWAP (&ftab[symidx], (ElfW(Addr)) NULL,
246	fdesc), 1))
247	{
248	/* Noone has updated the entry and the new function
249	descriptor has been installed. */
250	#if 0
251	const char *strtab
252	= (const void *) D_PTR (map, l_info[DT_STRTAB]);
253
254	ELF_MACHINE_LOAD_ADDRESS (l, local);
255	if (l->root != &l->boot_table
256	\|\| l->boot_table.first_unused > 20)
257	_dl_debug_printf ("created fdesc symbol `%s' at %lx\n",
258	strtab + sym->st_name, ftab[symidx]);
259	#endif
260	break;
261	}
262	else
263	{
264	/* We created a duplicated function descriptor. We put it on
265	free-list. */
266	struct fdesc f = (struct fdesc ) fdesc;
267
268	ELF_MACHINE_LOAD_ADDRESS (l, local);
269
270	do
271	f->ip = (ElfW(Addr)) l->free_list;
272	while (! COMPARE_AND_SWAP ((ElfW(Addr) *) &l->free_list,
273	f->ip, fdesc));
274	}
275	}
276
277	return ftab[symidx];
278	}
279
280
281	void
282	_dl_unmap (struct link_map *map)
283	{
284	ElfW(Addr) *ftab = map->l_mach.fptr_table;
285	struct fdesc head = NULL, tail = NULL;
286	size_t i;
287
fcccd512	288	_dl_unmap_segments (map);
dde6fc78 CD	289
	290	if (ftab == NULL)
	291	return;
	292
	293	/* String together the fdesc structures that are being freed. */
	294	for (i = 0; i < map->l_mach.fptr_table_len; ++i)
	295	{
	296	if (ftab[i])
	297	{
	298	(struct fdesc *) ftab[i] = head;
	299	head = (struct fdesc *) ftab[i];
	300	if (tail == NULL)
	301	tail = head;
	302	}
	303	}
	304
	305	/* Prepend the new list to the free_list: */
	306	if (tail)
	307	do
	308	tail->ip = (ElfW(Addr)) local.free_list;
	309	while (! COMPARE_AND_SWAP ((ElfW(Addr) *) &local.free_list,
	310	tail->ip, (ElfW(Addr)) head));
	311
	312	__munmap (ftab, (map->l_mach.fptr_table_len
	313	* sizeof (map->l_mach.fptr_table[0])));
	314
	315	map->l_mach.fptr_table = NULL;
	316	}
	317
	318
	319	ElfW(Addr)
	320	_dl_lookup_address (const void *address)
	321	{
	322	ElfW(Addr) addr = (ElfW(Addr)) address;
	323	struct fdesc_table *t;
	324	unsigned long int i;
	325
	326	for (t = local.root; t != NULL; t = t->next)
	327	{
	328	i = (struct fdesc *) addr - &t->fdesc[0];
	329	if (i < t->first_unused && addr == (ElfW(Addr)) &t->fdesc[i])
	330	{
	331	addr = t->fdesc[i].ip;
	332	break;
	333	}
	334	}
	335
	336	return addr;
	337	}