xref: /titanic_41/usr/src/lib/libc/port/threads/tls.c (revision 524e558aae3e99de2bdab73592f925ea489fbe07)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include "lint.h"
30 #include "thr_uberdata.h"
31 
32 #define	MIN_MOD_SLOTS	16
33 
34 /*
35  * To inform libc_init that we are on the primary link map.
36  */
37 int primary_link_map;
38 
39 #if defined(_LP64)
40 #define	ALIGN	16
41 #else
42 #define	ALIGN	8
43 #endif
44 
45 /*
46  * Grow the TLS module information array as necessary to include the
47  * specified module-id.  tls_modinfo->tls_size must be a power of two.
48  * Return a pointer to the (possibly reallocated) module information array.
49  */
50 static TLS_modinfo *
51 tls_modinfo_alloc(tls_metadata_t *tlsm, ulong_t moduleid)
52 {
53 	tls_t *tls_modinfo = &tlsm->tls_modinfo;
54 	TLS_modinfo *modinfo;
55 	size_t mod_slots;
56 
57 	if ((modinfo = tls_modinfo->tls_data) == NULL ||
58 	    tls_modinfo->tls_size <= moduleid) {
59 		if ((mod_slots = tls_modinfo->tls_size) == 0)
60 			mod_slots = MIN_MOD_SLOTS;
61 		while (mod_slots <= moduleid)
62 			mod_slots *= 2;
63 		modinfo = lmalloc(mod_slots * sizeof (TLS_modinfo));
64 		if (tls_modinfo->tls_data != NULL) {
65 			(void) _private_memcpy(modinfo, tls_modinfo->tls_data,
66 				tls_modinfo->tls_size * sizeof (TLS_modinfo));
67 			lfree(tls_modinfo->tls_data,
68 				tls_modinfo->tls_size * sizeof (TLS_modinfo));
69 		}
70 		tls_modinfo->tls_data = modinfo;
71 		tls_modinfo->tls_size = mod_slots;
72 	}
73 	return (modinfo);
74 }
75 
76 /*
77  * This is called from the dynamic linker, before libc_init() is called,
78  * to setup all of the TLS blocks that are available at process startup
79  * and hence must be included as part of the static TLS block.
80  * No locks are needed because we are single-threaded at this point.
81  * We must be careful not to call any function that could possibly
82  * invoke the dynamic linker.  That is, we must only call functions
83  * that are wholly private to libc.
84  */
85 void
86 __tls_static_mods(TLS_modinfo **tlslist, unsigned long statictlssize)
87 {
88 	ulwp_t *oldself = __curthread();
89 	tls_metadata_t *tlsm;
90 	TLS_modinfo **tlspp;
91 	TLS_modinfo *tlsp;
92 	TLS_modinfo *modinfo;
93 	caddr_t data;
94 	caddr_t data_end;
95 	int max_modid;
96 
97 	primary_link_map = 1;		/* inform libc_init */
98 	if (statictlssize == 0)
99 		return;
100 
101 	/*
102 	 * Retrieve whatever dynamic TLS metadata was generated by code
103 	 * running on alternate link maps prior to now (we must be running
104 	 * on the primary link map now since __tls_static_mods() is only
105 	 * called on the primary link map).
106 	 */
107 	tlsm = &__uberdata.tls_metadata;
108 	if (oldself != NULL) {
109 		(void) _private_memcpy(tlsm,
110 		    &oldself->ul_uberdata->tls_metadata, sizeof (*tlsm));
111 		ASSERT(tlsm->static_tls.tls_data == NULL);
112 	}
113 
114 	/*
115 	 * We call lmalloc() to allocate the template even though libc_init()
116 	 * has not yet been called.  lmalloc() must and does deal with this.
117 	 */
118 	ASSERT((statictlssize & (ALIGN - 1)) == 0);
119 	tlsm->static_tls.tls_data = data = lmalloc(statictlssize);
120 	data_end = data + statictlssize;
121 	tlsm->static_tls.tls_size = statictlssize;
122 	/*
123 	 * Initialize the static TLS template.
124 	 * We make no assumptions about the order in memory of the TLS
125 	 * modules we are processing, only that they fit within the
126 	 * total size we are given and that they are self-consistent.
127 	 * We do not assume any order for the moduleid's; we only assume
128 	 * that they are reasonably small integers.
129 	 */
130 	for (max_modid = 0, tlspp = tlslist; (tlsp = *tlspp) != NULL; tlspp++) {
131 		ASSERT(tlsp->tm_flags & TM_FLG_STATICTLS);
132 		ASSERT(tlsp->tm_stattlsoffset > 0);
133 		ASSERT(tlsp->tm_stattlsoffset <= statictlssize);
134 		ASSERT((tlsp->tm_stattlsoffset & (ALIGN - 1)) == 0);
135 		ASSERT(tlsp->tm_filesz <= tlsp->tm_memsz);
136 		ASSERT(tlsp->tm_memsz <= tlsp->tm_stattlsoffset);
137 		if (tlsp->tm_filesz)
138 			(void) _private_memcpy(data_end-tlsp->tm_stattlsoffset,
139 				tlsp->tm_tlsblock, tlsp->tm_filesz);
140 		if (max_modid < tlsp->tm_modid)
141 			max_modid = tlsp->tm_modid;
142 	}
143 	/*
144 	 * Record the static TLS_modinfo information.
145 	 */
146 	modinfo = tls_modinfo_alloc(tlsm, max_modid);
147 	for (tlspp = tlslist; (tlsp = *tlspp) != NULL; tlspp++)
148 		(void) _private_memcpy(&modinfo[tlsp->tm_modid],
149 		    tlsp, sizeof (*tlsp));
150 
151 	/*
152 	 * Copy the new tls_metadata back to the old, if any,
153 	 * since it will be copied up again in libc_init().
154 	 */
155 	if (oldself != NULL)
156 		(void) _private_memcpy(&oldself->ul_uberdata->tls_metadata,
157 		    tlsm, sizeof (*tlsm));
158 }
159 
160 /*
161  * This is called from the dynamic linker for each module not included
162  * in the static TLS mod list, after the module has been loaded but
163  * before any of the module's init code has been executed.
164  */
165 void
166 __tls_mod_add(TLS_modinfo *tlsp)
167 {
168 	tls_metadata_t *tlsm = &curthread->ul_uberdata->tls_metadata;
169 	ulong_t moduleid = tlsp->tm_modid;
170 	TLS_modinfo *modinfo;
171 
172 	lmutex_lock(&tlsm->tls_lock);
173 	ASSERT(!(tlsp->tm_flags & TM_FLG_STATICTLS));
174 	ASSERT(tlsp->tm_filesz <= tlsp->tm_memsz);
175 	modinfo = tls_modinfo_alloc(tlsm, moduleid);
176 	(void) _private_memcpy(&modinfo[moduleid], tlsp, sizeof (*tlsp));
177 	lmutex_unlock(&tlsm->tls_lock);
178 }
179 
180 /*
181  * Called for each module as it is unloaded from memory by dlclose().
182  */
183 void
184 __tls_mod_remove(TLS_modinfo *tlsp)
185 {
186 	tls_metadata_t *tlsm = &curthread->ul_uberdata->tls_metadata;
187 	ulong_t moduleid = tlsp->tm_modid;
188 	TLS_modinfo *modinfo;
189 
190 	lmutex_lock(&tlsm->tls_lock);
191 	ASSERT(tlsm->tls_modinfo.tls_data != NULL &&
192 	    moduleid < tlsm->tls_modinfo.tls_size);
193 	modinfo = tlsm->tls_modinfo.tls_data;
194 	(void) _private_memset(&modinfo[moduleid], 0, sizeof (TLS_modinfo));
195 	lmutex_unlock(&tlsm->tls_lock);
196 }
197 
198 extern	int	_preexec_exit_handlers();
199 extern	void	libc_init();
200 
201 const Lc_interface tls_rtldinfo[] = {
202 	{CI_VERSION,	(int(*)())CI_V_CURRENT},
203 	{CI_ATEXIT,	(int(*)())_preexec_exit_handlers},
204 	{CI_TLS_MODADD,	(int(*)())__tls_mod_add},
205 	{CI_TLS_MODREM,	(int(*)())__tls_mod_remove},
206 	{CI_TLS_STATMOD, (int(*)())__tls_static_mods},
207 	{CI_THRINIT,	(int(*)())libc_init},
208 	{CI_NULL,	(int(*)())NULL}
209 };
210 
211 /*
212  * Return the address of a TLS variable for the current thread.
213  * Run the constructors for newly-allocated dynamic TLS.
214  */
215 void *
216 slow_tls_get_addr(TLS_index *tls_index)
217 {
218 	ulwp_t *self = curthread;
219 	tls_metadata_t *tlsm = &self->ul_uberdata->tls_metadata;
220 	TLS_modinfo *tlsp;
221 	ulong_t moduleid;
222 	tls_t *tlsent;
223 	caddr_t	base;
224 	void (**initarray)(void);
225 	ulong_t arraycnt = 0;
226 
227 	/*
228 	 * Defer signals until we have finished calling
229 	 * all of the constructors.
230 	 */
231 	sigoff(self);
232 	lmutex_lock(&tlsm->tls_lock);
233 	if ((moduleid = tls_index->ti_moduleid) < self->ul_ntlsent)
234 		tlsent = self->ul_tlsent;
235 	else {
236 		ASSERT(moduleid < tlsm->tls_modinfo.tls_size);
237 		tlsent = lmalloc(tlsm->tls_modinfo.tls_size * sizeof (tls_t));
238 		if (self->ul_tlsent != NULL) {
239 			(void) _private_memcpy(tlsent, self->ul_tlsent,
240 				self->ul_ntlsent * sizeof (tls_t));
241 			lfree(self->ul_tlsent,
242 				self->ul_ntlsent * sizeof (tls_t));
243 		}
244 		self->ul_tlsent = tlsent;
245 		self->ul_ntlsent = tlsm->tls_modinfo.tls_size;
246 	}
247 	tlsent += moduleid;
248 	if ((base = tlsent->tls_data) == NULL) {
249 		tlsp = (TLS_modinfo *)tlsm->tls_modinfo.tls_data + moduleid;
250 		if (tlsp->tm_memsz == 0) {	/* dlclose()d module? */
251 			base = NULL;
252 		} else if (tlsp->tm_flags & TM_FLG_STATICTLS) {
253 			/* static TLS is already allocated/initialized */
254 			base = (caddr_t)self - tlsp->tm_stattlsoffset;
255 			tlsent->tls_data = base;
256 			tlsent->tls_size = 0;	/* don't lfree() this space */
257 		} else {
258 			/* allocate/initialize the dynamic TLS */
259 			base = lmalloc(tlsp->tm_memsz);
260 			if (tlsp->tm_filesz != 0)
261 				(void) _private_memcpy(base, tlsp->tm_tlsblock,
262 					tlsp->tm_filesz);
263 			tlsent->tls_data = base;
264 			tlsent->tls_size = tlsp->tm_memsz;
265 			/* remember the constructors */
266 			arraycnt = tlsp->tm_tlsinitarraycnt;
267 			initarray = tlsp->tm_tlsinitarray;
268 		}
269 	}
270 	lmutex_unlock(&tlsm->tls_lock);
271 
272 	/*
273 	 * Call constructors, if any, in ascending order.
274 	 * We have to do this after dropping tls_lock because
275 	 * we have no idea what the constructors will do.
276 	 * At least we have signals deferred until they are done.
277 	 */
278 	if (arraycnt) {
279 		do {
280 			(**initarray++)();
281 		} while (--arraycnt != 0);
282 	}
283 
284 	sigon(self);
285 	return (base + tls_index->ti_tlsoffset);
286 }
287 
288 #ifdef	TLS_GET_ADDR_IS_WRITTEN_IN_ASSEMBLER
289 /*
290  * For speed, we do not make reference to any static data in this function.
291  * If necessary to do so, we do a tail call to slow_tls_get_addr().
292  */
293 void *
294 __tls_get_addr(TLS_index *tls_index)
295 {
296 	ulwp_t *self = curthread;
297 	tls_t *tlsent = self->ul_tlsent;
298 	ulong_t moduleid;
299 	caddr_t	base;
300 
301 	if ((moduleid = tls_index->ti_moduleid) < self->ul_ntlsent &&
302 	    (base = tlsent[moduleid].tls_data) != NULL)
303 		return (base + tls_index->ti_tlsoffset);
304 
305 	return (slow_tls_get_addr(tls_index));
306 }
307 #endif	/* TLS_GET_ADDR_IS_WRITTEN_IN_ASSEMBLER */
308 
309 /*
310  * This is called by _thr_setup() to initialize the thread's static TLS.
311  * Constructors for initially allocated static TLS are called here.
312  */
313 void
314 tls_setup()
315 {
316 	ulwp_t *self = curthread;
317 	tls_metadata_t *tlsm = &self->ul_uberdata->tls_metadata;
318 	TLS_modinfo *tlsp;
319 	long moduleid;
320 	ulong_t nmods;
321 
322 	if (tlsm->static_tls.tls_size == 0)	/* no static TLS */
323 		return;
324 
325 	/* static TLS initialization */
326 	(void) _private_memcpy((caddr_t)self - tlsm->static_tls.tls_size,
327 		tlsm->static_tls.tls_data, tlsm->static_tls.tls_size);
328 
329 	/* call TLS constructors for the static TLS just initialized */
330 	lmutex_lock(&tlsm->tls_lock);
331 	nmods = tlsm->tls_modinfo.tls_size;
332 	for (moduleid = 0; moduleid < nmods; moduleid++) {
333 		/*
334 		 * Resume where we left off in the module array.
335 		 * tls_modinfo.tls_data may have changed since we
336 		 * dropped and reacquired tls_lock, but TLS modules
337 		 * retain their positions in the new array.
338 		 */
339 		tlsp = (TLS_modinfo *)tlsm->tls_modinfo.tls_data + moduleid;
340 		/*
341 		 * Call constructors for this module if there are any
342 		 * to be called and if it is part of the static TLS.
343 		 */
344 		if (tlsp->tm_tlsinitarraycnt != 0 &&
345 		    (tlsp->tm_flags & TM_FLG_STATICTLS)) {
346 			ulong_t arraycnt = tlsp->tm_tlsinitarraycnt;
347 			void (**initarray)(void) = tlsp->tm_tlsinitarray;
348 
349 			/*
350 			 * Call the constructors in ascending order.
351 			 * We must drop tls_lock while doing this because
352 			 * we have no idea what the constructors will do.
353 			 */
354 			lmutex_unlock(&tlsm->tls_lock);
355 			do {
356 				(**initarray++)();
357 			} while (--arraycnt != 0);
358 			lmutex_lock(&tlsm->tls_lock);
359 		}
360 	}
361 	lmutex_unlock(&tlsm->tls_lock);
362 }
363 
364 /*
365  * This is called by _thrp_exit() to deallocate the thread's TLS.
366  * Destructors for all allocated TLS are called here.
367  */
368 void
369 tls_exit()
370 {
371 	ulwp_t *self = curthread;
372 	tls_metadata_t *tlsm = &self->ul_uberdata->tls_metadata;
373 	tls_t *tlsent;
374 	TLS_modinfo *tlsp;
375 	long moduleid;
376 	ulong_t nmods;
377 
378 	if (tlsm->static_tls.tls_size == 0 && self->ul_ntlsent == 0)
379 		return;		/* no TLS */
380 
381 	/*
382 	 * Call TLS destructors for all TLS allocated for this thread.
383 	 */
384 	lmutex_lock(&tlsm->tls_lock);
385 	nmods = tlsm->tls_modinfo.tls_size;
386 	for (moduleid = nmods - 1; moduleid >= 0; --moduleid) {
387 		/*
388 		 * Resume where we left off in the module array.
389 		 * tls_modinfo.tls_data may have changed since we
390 		 * dropped and reacquired tls_lock, but TLS modules
391 		 * retain their positions in the new array.
392 		 */
393 		tlsp = (TLS_modinfo *)tlsm->tls_modinfo.tls_data + moduleid;
394 		/*
395 		 * Call destructors for this module if there are any
396 		 * to be called and if it is part of the static TLS or
397 		 * if the dynamic TLS for the module has been allocated.
398 		 */
399 		if (tlsp->tm_tlsfiniarraycnt != 0 &&
400 		    ((tlsp->tm_flags & TM_FLG_STATICTLS) ||
401 		    (moduleid < self->ul_ntlsent &&
402 		    (tlsent = self->ul_tlsent) != NULL &&
403 		    tlsent[moduleid].tls_data != NULL))) {
404 			ulong_t arraycnt = tlsp->tm_tlsfiniarraycnt;
405 			void (**finiarray)(void) = tlsp->tm_tlsfiniarray;
406 
407 			/*
408 			 * Call the destructors in descending order.
409 			 * We must drop tls_lock while doing this because
410 			 * we have no idea what the destructors will do.
411 			 */
412 			lmutex_unlock(&tlsm->tls_lock);
413 			finiarray += arraycnt;
414 			do {
415 				(**--finiarray)();
416 			} while (--arraycnt != 0);
417 			lmutex_lock(&tlsm->tls_lock);
418 		}
419 	}
420 	lmutex_unlock(&tlsm->tls_lock);
421 
422 	tls_free(self);
423 }
424 
425 /*
426  * We only free the dynamically allocated TLS; the statically
427  * allocated TLS is reused when the ulwp_t is reallocated.
428  */
429 void
430 tls_free(ulwp_t *ulwp)
431 {
432 	ulong_t moduleid;
433 	tls_t *tlsent;
434 	size_t ntlsent;
435 	void *base;
436 	size_t size;
437 
438 	if ((tlsent = ulwp->ul_tlsent) == NULL ||
439 	    (ntlsent = ulwp->ul_ntlsent) == 0)
440 		return;
441 
442 	for (moduleid = 0; moduleid < ntlsent; moduleid++, tlsent++) {
443 		if ((base = tlsent->tls_data) != NULL &&
444 		    (size = tlsent->tls_size) != 0)
445 			lfree(base, size);
446 		tlsent->tls_data = NULL;	/* paranoia */
447 		tlsent->tls_size = 0;
448 	}
449 	lfree(ulwp->ul_tlsent, ntlsent * sizeof (tls_t));
450 	ulwp->ul_tlsent = NULL;
451 	ulwp->ul_ntlsent = 0;
452 }
453