xref: /titanic_51/usr/src/cmd/sgs/rtld/common/tls.c (revision d42c7aec1963a7ded6694ac33a5bd96422fc8ca7)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #include <stdio.h>
28 #include <strings.h>
29 #include <sys/types.h>
30 #include <dlfcn.h>
31 #include <libc_int.h>
32 #include <_rtld.h>
33 #include <_elf.h>
34 #include <msg.h>
35 #include <debug.h>
36 
37 #define	TLSBLOCKCNT	16	/* number of blocks of tmi_bits to allocate */
38 				/* at a time. */
39 typedef struct {
40 	uint_t	*tmi_bits;
41 	ulong_t	tmi_lowfree;
42 	ulong_t	tmi_cnt;
43 } Tlsmodid;
44 
45 static Tlsmodid	tmid = {0, 0, 0};
46 
47 static ulong_t
48 tls_getmodid()
49 {
50 	ulong_t	ndx, cnt;
51 
52 	if (tmid.tmi_bits == 0) {
53 		if ((tmid.tmi_bits = calloc(TLSBLOCKCNT, sizeof (uint_t))) == 0)
54 			return ((ulong_t)-1);
55 		tmid.tmi_bits[0] = 1;
56 		tmid.tmi_lowfree = 1;
57 		tmid.tmi_cnt = TLSBLOCKCNT;
58 		return (0);
59 	}
60 
61 	for (cnt = tmid.tmi_lowfree / (sizeof (uint_t) * 8);
62 	    cnt < tmid.tmi_cnt; cnt++) {
63 		uint_t	bits;
64 
65 		/*
66 		 * If all bits are assigned - move on.
67 		 */
68 		if ((tmid.tmi_bits[cnt] ^ ~((uint_t)0)) == 0)
69 			continue;
70 
71 		for (ndx = 0, bits = 1; bits; bits = bits << 1, ndx++) {
72 			if ((tmid.tmi_bits[cnt] & bits) == 0) {
73 				tmid.tmi_bits[cnt] |= bits;
74 				ndx = (cnt * (sizeof (uint_t)) * 8) + ndx;
75 				tmid.tmi_lowfree = ndx + 1;
76 				return (ndx);
77 			}
78 		}
79 	}
80 
81 	/*
82 	 * All bits taken - must allocate a new block
83 	 */
84 	if ((tmid.tmi_bits = realloc(tmid.tmi_bits,
85 	    ((tmid.tmi_cnt * sizeof (uint_t)) +
86 	    (TLSBLOCKCNT * sizeof (uint_t))))) == 0)
87 		return ((ulong_t)-1);
88 
89 	/*
90 	 * Clear out the tail of the new allocation.
91 	 */
92 	bzero(&(tmid.tmi_bits[tmid.tmi_cnt]), TLSBLOCKCNT * sizeof (uint_t));
93 	tmid.tmi_bits[tmid.tmi_cnt] = 1;
94 	ndx = (tmid.tmi_cnt * sizeof (uint_t)) * 8;
95 	tmid.tmi_lowfree = ndx + 1;
96 	tmid.tmi_cnt += TLSBLOCKCNT;
97 
98 	return (ndx);
99 }
100 
101 void
102 tls_freemodid(ulong_t modid)
103 {
104 	ulong_t	i;
105 	uint_t	j;
106 
107 	i = modid / (sizeof (uint_t) * 8);
108 	/* LINTED */
109 	j = modid % (sizeof (uint_t) * 8);
110 	j = ~(1 << j);
111 	tmid.tmi_bits[i] &= j;
112 	if (modid < tmid.tmi_lowfree)
113 		tmid.tmi_lowfree = modid;
114 }
115 
116 void
117 tls_modaddrem(Rt_map *lmp, uint_t flag)
118 {
119 	Lm_list		*lml = LIST(lmp);
120 	TLS_modinfo	tmi;
121 	Phdr		*tlsphdr;
122 	void		(*fptr)(TLS_modinfo *);
123 
124 	if (flag & TM_FLG_MODADD) {
125 		fptr = (void (*)())lml->lm_lcs[CI_TLS_MODADD].lc_un.lc_func;
126 	} else if (FLAGS1(lmp) & FL1_RT_TLSADD) {
127 		fptr = (void (*)())lml->lm_lcs[CI_TLS_MODREM].lc_un.lc_func;
128 	} else {
129 		return;
130 	}
131 
132 	tlsphdr = PTTLS(lmp);
133 
134 	bzero(&tmi, sizeof (tmi));
135 	tmi.tm_modname = PATHNAME(lmp);
136 	tmi.tm_modid = TLSMODID(lmp);
137 	tmi.tm_tlsblock = (void *)(tlsphdr->p_vaddr);
138 
139 	if (!(FLAGS(lmp) & FLG_RT_FIXED))
140 		tmi.tm_tlsblock = (void *)((uintptr_t)tmi.tm_tlsblock +
141 		    ADDR(lmp));
142 
143 	tmi.tm_filesz = tlsphdr->p_filesz;
144 	tmi.tm_memsz = tlsphdr->p_memsz;
145 	tmi.tm_flags = 0;
146 	tmi.tm_stattlsoffset = 0;
147 
148 	DBG_CALL(Dbg_tls_modactivity(LIST(lmp), &tmi, flag));
149 	(*fptr)(&tmi);
150 
151 	/*
152 	 * Tag that this link-map has registered its TLS, and, if this object
153 	 * is being removed, free up the module id.
154 	 */
155 	FLAGS1(lmp) |= FL1_RT_TLSADD;
156 
157 	if (flag & TM_FLG_MODREM)
158 		tls_freemodid(TLSMODID(lmp));
159 }
160 
161 static ulong_t	tls_static_size = 0;	/* static TLS buffer size */
162 static ulong_t	tls_static_resv = 512;	/* (extra) static TLS reservation */
163 
164 /*
165  * Track any static TLS use, retain the TLS header, and assign a TLS module
166  * identifier.
167  */
168 int
169 tls_assign(Lm_list *lml, Rt_map *lmp, Phdr *phdr)
170 {
171 	ulong_t	memsz = S_ROUND(phdr->p_memsz, M_TLSSTATALIGN);
172 	ulong_t	filesz = phdr->p_filesz;
173 	ulong_t	resv = tls_static_resv;
174 
175 	/*
176 	 * If this object explicitly references static TLS, then there are some
177 	 * limitations.
178 	 */
179 	if (FLAGS1(lmp) & FL1_RT_TLSSTAT) {
180 		/*
181 		 * Static TLS is only available to objects on the primary
182 		 * link-map list.
183 		 */
184 		if (((lml->lm_flags & LML_FLG_BASELM) == 0) ||
185 		    ((rtld_flags2 & RT_FL2_NOPLM) != 0)) {
186 			eprintf(lml, ERR_FATAL, MSG_INTL(MSG_TLS_STATBASE),
187 			    NAME(lmp));
188 			return (0);
189 		}
190 
191 		/*
192 		 * All TLS blocks that are processed before thread
193 		 * initialization, are registered with libc.  This
194 		 * initialization is carried out through a handshake with libc
195 		 * prior to executing any user code (ie. before the first .init
196 		 * sections are called).  As part of this initialization, a
197 		 * small backup TLS reservation is added (tls_static_resv).
198 		 * Only explicit static TLS references that can be satisfied by
199 		 * this TLS backup reservation can be satisfied.
200 		 */
201 		if (rtld_flags2 & RT_FL2_PLMSETUP) {
202 			/*
203 			 * Initialized static TLS can not be satisfied from the
204 			 * TLS backup reservation.
205 			 */
206 			if (filesz) {
207 				eprintf(lml, ERR_FATAL,
208 				    MSG_INTL(MSG_TLS_STATINIT), NAME(lmp));
209 				return (0);
210 			}
211 
212 			/*
213 			 * Make sure the backup reservation is sufficient.
214 			 */
215 			if (memsz > tls_static_resv) {
216 				eprintf(lml, ERR_FATAL,
217 				    MSG_INTL(MSG_TLS_STATSIZE), NAME(lmp),
218 				    EC_XWORD(memsz), EC_XWORD(tls_static_resv));
219 				return (0);
220 			}
221 
222 			tls_static_resv -= memsz;
223 		}
224 	}
225 
226 	/*
227 	 * If we haven't yet initialized threads, or this static reservation can
228 	 * be satisfied from the TLS backup reservation, determine the total
229 	 * static TLS size, and assign this object a static TLS offset.
230 	 */
231 	if (((rtld_flags2 & RT_FL2_PLMSETUP) == 0) ||
232 	    (FLAGS1(lmp) & FL1_RT_TLSSTAT)) {
233 		tls_static_size += memsz;
234 		TLSSTATOFF(lmp) = tls_static_size;
235 	}
236 
237 	/*
238 	 * Retain the PT_TLS header, obtain a new module identifier, and
239 	 * indicate that this link-map list contains a new TLS object.
240 	 */
241 	PTTLS(lmp) = phdr;
242 	TLSMODID(lmp) = tls_getmodid();
243 
244 	/*
245 	 * Now that we have a TLS module id, generate any static TLS reservation
246 	 * diagnostic.
247 	 */
248 	if (resv != tls_static_resv)
249 		DBG_CALL(Dbg_tls_static_resv(lmp, memsz, tls_static_resv));
250 
251 	return (++lml->lm_tls);
252 }
253 
254 int
255 tls_statmod(Lm_list *lml, Rt_map *lmp)
256 {
257 	uint_t		tlsmodndx, tlsmodcnt = lml->lm_tls;
258 	TLS_modinfo	**tlsmodlist, *tlsbuflist;
259 	Phdr		*tlsphdr;
260 	void		(*fptr)(TLS_modinfo **, ulong_t);
261 
262 	fptr = (void (*)())lml->lm_lcs[CI_TLS_STATMOD].lc_un.lc_func;
263 
264 	/*
265 	 * Allocate a buffer to report the TLS modules, the buffer consists of:
266 	 *
267 	 *	TLS_modinfo *	ptrs[tlsmodcnt + 1]
268 	 *	TLS_modinfo	bufs[tlsmodcnt]
269 	 *
270 	 * The ptrs are initialized to the bufs - except the last one which
271 	 * null terminates the array.
272 	 *
273 	 * Note, even if no TLS has yet been observed, we still supply a
274 	 * TLS buffer with a single null entry.  This allows us to initialize
275 	 * the backup TLS reservation.
276 	 */
277 	if ((tlsmodlist = calloc((sizeof (TLS_modinfo *) * (tlsmodcnt + 1)) +
278 	    (sizeof (TLS_modinfo) * tlsmodcnt), 1)) == 0)
279 		return (0);
280 
281 	lml->lm_tls = 0;
282 
283 	/*
284 	 * If we don't have any TLS modules - report that and return.
285 	 */
286 	if (tlsmodcnt == 0) {
287 		if (fptr)
288 			(*fptr)(tlsmodlist, tls_static_resv);
289 		DBG_CALL(Dbg_tls_static_block(&lml_main, 0, 0,
290 		    tls_static_resv));
291 		return (1);
292 	}
293 
294 	/*
295 	 * Initialize the TLS buffer.
296 	 */
297 	tlsbuflist = (TLS_modinfo *)((uintptr_t)tlsmodlist +
298 	    ((tlsmodcnt + 1) * sizeof (TLS_modinfo *)));
299 
300 	for (tlsmodndx = 0; tlsmodndx < tlsmodcnt; tlsmodndx++)
301 		tlsmodlist[tlsmodndx] = &tlsbuflist[tlsmodndx];
302 
303 	/*
304 	 * Account for the initial dtv ptr in the TLSSIZE calculation.
305 	 */
306 	tlsmodndx = 0;
307 	for (lmp = lml->lm_head; lmp; lmp = NEXT_RT_MAP(lmp)) {
308 		if ((FCT(lmp) != &elf_fct) ||
309 		    (PTTLS(lmp) == 0) || (PTTLS(lmp)->p_memsz == 0))
310 			continue;
311 
312 		tlsphdr = PTTLS(lmp);
313 
314 		tlsmodlist[tlsmodndx]->tm_modname = PATHNAME(lmp);
315 		tlsmodlist[tlsmodndx]->tm_modid = TLSMODID(lmp);
316 		tlsmodlist[tlsmodndx]->tm_tlsblock = (void *)(tlsphdr->p_vaddr);
317 
318 		if (!(FLAGS(lmp) & FLG_RT_FIXED)) {
319 			tlsmodlist[tlsmodndx]->tm_tlsblock = (void *)
320 			    ((uintptr_t)tlsmodlist[tlsmodndx]->tm_tlsblock +
321 			    ADDR(lmp));
322 		}
323 		tlsmodlist[tlsmodndx]->tm_filesz = tlsphdr->p_filesz;
324 		tlsmodlist[tlsmodndx]->tm_memsz = tlsphdr->p_memsz;
325 		tlsmodlist[tlsmodndx]->tm_flags = TM_FLG_STATICTLS;
326 		tlsmodlist[tlsmodndx]->tm_stattlsoffset = TLSSTATOFF(lmp);
327 		tlsmodndx++;
328 	}
329 
330 	DBG_CALL(Dbg_tls_static_block(&lml_main, (void *)tlsmodlist,
331 	    tls_static_size, tls_static_resv));
332 	(*fptr)(tlsmodlist, (tls_static_size + tls_static_resv));
333 
334 	/*
335 	 * We're done with the list - clean it up.
336 	 */
337 	free(tlsmodlist);
338 	return (1);
339 }
340