Mercurial > hg > CbC > CbC_gcc
annotate gcc/config/vxlib-tls.c @ 55:77e2b8dfacca gcc-4.4.5
update it from 4.4.3 to 4.5.0
| author | ryoma <e075725@ie.u-ryukyu.ac.jp> |
|---|---|
| date | Fri, 12 Feb 2010 23:39:51 +0900 |
| parents | a06113de4d67 |
| children |
| rev | line source |
|---|---|
| 0 | 1 /* Copyright (C) 2002, 2003, 2004, 2005, 2009 Free Software Foundation, Inc. |
| 2 Contributed by Zack Weinberg <zack@codesourcery.com> | |
| 3 | |
| 4 This file is part of GCC. | |
| 5 | |
| 6 GCC is free software; you can redistribute it and/or modify it under | |
| 7 the terms of the GNU General Public License as published by the Free | |
| 8 Software Foundation; either version 3, or (at your option) any later | |
| 9 version. | |
| 10 | |
| 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
| 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 for more details. | |
| 15 | |
| 16 Under Section 7 of GPL version 3, you are granted additional | |
| 17 permissions described in the GCC Runtime Library Exception, version | |
| 18 3.1, as published by the Free Software Foundation. | |
| 19 | |
| 20 You should have received a copy of the GNU General Public License and | |
| 21 a copy of the GCC Runtime Library Exception along with this program; | |
| 22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
| 23 <http://www.gnu.org/licenses/>. */ | |
| 24 | |
| 25 /* Threads compatibility routines for libgcc2 for VxWorks. | |
| 26 These are out-of-line routines called from gthr-vxworks.h. | |
| 27 | |
| 28 This file provides the TLS related support routines, calling specific | |
| 29 VxWorks kernel entry points for this purpose. The base VxWorks 5.x kernels | |
| 30 don't feature these entry points, and we provide gthr_supp_vxw_5x.c as an | |
| 31 option to fill this gap. Asking users to rebuild a kernel is not to be | |
| 32 taken lightly, still, so we have isolated these routines from the rest of | |
| 33 vxlib to ensure that the kernel dependencies are only dragged when really | |
| 34 necessary. */ | |
| 35 | |
| 36 #include "tconfig.h" | |
| 37 #include "tsystem.h" | |
| 38 #include "gthr.h" | |
| 39 | |
| 40 #if defined(__GTHREADS) | |
| 41 #include <vxWorks.h> | |
| 42 #ifndef __RTP__ | |
| 43 #include <vxLib.h> | |
| 44 #endif | |
| 45 #include <taskLib.h> | |
| 46 #ifndef __RTP__ | |
| 47 #include <taskHookLib.h> | |
| 48 #else | |
| 49 # include <errno.h> | |
| 50 #endif | |
| 51 | |
| 52 /* Thread-local storage. | |
| 53 | |
| 54 We reserve a field in the TCB to point to a dynamically allocated | |
| 55 array which is used to store TLS values. A TLS key is simply an | |
| 56 offset in this array. The exact location of the TCB field is not | |
| 57 known to this code nor to vxlib.c -- all access to it indirects | |
| 58 through the routines __gthread_get_tls_data and | |
| 59 __gthread_set_tls_data, which are provided by the VxWorks kernel. | |
| 60 | |
| 61 There is also a global array which records which keys are valid and | |
| 62 which have destructors. | |
| 63 | |
| 64 A task delete hook is installed to execute key destructors. The | |
| 65 routines __gthread_enter_tls_dtor_context and | |
| 66 __gthread_leave_tls_dtor_context, which are also provided by the | |
| 67 kernel, ensure that it is safe to call free() on memory allocated | |
| 68 by the task being deleted. (This is a no-op on VxWorks 5, but | |
| 69 a major undertaking on AE.) | |
| 70 | |
| 71 The task delete hook is only installed when at least one thread | |
| 72 has TLS data. This is a necessary precaution, to allow this module | |
| 73 to be unloaded - a module with a hook can not be removed. | |
| 74 | |
| 75 Since this interface is used to allocate only a small number of | |
| 76 keys, the table size is small and static, which simplifies the | |
| 77 code quite a bit. Revisit this if and when it becomes necessary. */ | |
| 78 | |
| 79 #define MAX_KEYS 4 | |
| 80 | |
| 81 /* This is the structure pointed to by the pointer returned | |
| 82 by __gthread_get_tls_data. */ | |
| 83 struct tls_data | |
| 84 { | |
| 85 int *owner; | |
| 86 void *values[MAX_KEYS]; | |
| 87 unsigned int generation[MAX_KEYS]; | |
| 88 }; | |
| 89 | |
| 90 /* To make sure we only delete TLS data associated with this object, | |
| 91 include a pointer to a local variable in the TLS data object. */ | |
| 92 static int self_owner; | |
| 93 | |
|
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94 /* Flag to check whether the delete hook is installed. Once installed |
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95 it is only removed when unloading this module. */ |
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96 static volatile int delete_hook_installed; |
| 0 | 97 |
| 98 /* kernel provided routines */ | |
| 99 extern void *__gthread_get_tls_data (void); | |
| 100 extern void __gthread_set_tls_data (void *data); | |
| 101 | |
| 102 extern void __gthread_enter_tls_dtor_context (void); | |
| 103 extern void __gthread_leave_tls_dtor_context (void); | |
| 104 | |
| 105 | |
| 106 /* This is a global structure which records all of the active keys. | |
| 107 | |
| 108 A key is potentially valid (i.e. has been handed out by | |
| 109 __gthread_key_create) iff its generation count in this structure is | |
| 110 even. In that case, the matching entry in the dtors array is a | |
| 111 routine to be called when a thread terminates with a valid, | |
| 112 non-NULL specific value for that key. | |
| 113 | |
| 114 A key is actually valid in a thread T iff the generation count | |
| 115 stored in this structure is equal to the generation count stored in | |
| 116 T's specific-value structure. */ | |
| 117 | |
| 118 typedef void (*tls_dtor) (void *); | |
| 119 | |
| 120 struct tls_keys | |
| 121 { | |
| 122 tls_dtor dtor[MAX_KEYS]; | |
| 123 unsigned int generation[MAX_KEYS]; | |
| 124 }; | |
| 125 | |
| 126 #define KEY_VALID_P(key) !(tls_keys.generation[key] & 1) | |
| 127 | |
| 128 /* Note: if MAX_KEYS is increased, this initializer must be updated | |
| 129 to match. All the generation counts begin at 1, which means no | |
| 130 key is valid. */ | |
| 131 static struct tls_keys tls_keys = | |
| 132 { | |
| 133 { 0, 0, 0, 0 }, | |
| 134 { 1, 1, 1, 1 } | |
| 135 }; | |
| 136 | |
| 137 /* This lock protects the tls_keys structure. */ | |
| 138 static __gthread_mutex_t tls_lock; | |
| 139 | |
| 140 static __gthread_once_t tls_init_guard = __GTHREAD_ONCE_INIT; | |
| 141 | |
| 142 /* Internal routines. */ | |
| 143 | |
| 144 /* The task TCB has just been deleted. Call the destructor | |
| 145 function for each TLS key that has both a destructor and | |
| 146 a non-NULL specific value in this thread. | |
| 147 | |
| 148 This routine does not need to take tls_lock; the generation | |
| 149 count protects us from calling a stale destructor. It does | |
| 150 need to read tls_keys.dtor[key] atomically. */ | |
| 151 | |
| 152 static void | |
| 153 tls_delete_hook (void *tcb ATTRIBUTE_UNUSED) | |
| 154 { | |
| 155 struct tls_data *data; | |
| 156 __gthread_key_t key; | |
| 157 | |
| 158 #ifdef __RTP__ | |
| 159 data = __gthread_get_tls_data (); | |
| 160 #else | |
| 161 /* In kernel mode, we can be called in the context of the thread | |
| 162 doing the killing, so must use the TCB to determine the data of | |
| 163 the thread being killed. */ | |
| 164 data = __gthread_get_tsd_data (tcb); | |
| 165 #endif | |
| 166 | |
| 167 if (data && data->owner == &self_owner) | |
| 168 { | |
|
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169 #ifdef __RTP__ |
| 0 | 170 __gthread_enter_tls_dtor_context (); |
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171 #else |
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172 __gthread_enter_tsd_dtor_context (tcb); |
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173 #endif |
| 0 | 174 for (key = 0; key < MAX_KEYS; key++) |
| 175 { | |
| 176 if (data->generation[key] == tls_keys.generation[key]) | |
| 177 { | |
| 178 tls_dtor dtor = tls_keys.dtor[key]; | |
| 179 | |
| 180 if (dtor) | |
| 181 dtor (data->values[key]); | |
| 182 } | |
| 183 } | |
| 184 free (data); | |
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185 #ifdef __RTP__ |
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186 __gthread_leave_tls_dtor_context (); |
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187 #else |
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188 __gthread_leave_tsd_dtor_context (); |
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189 #endif |
| 0 | 190 |
| 191 #ifdef __RTP__ | |
| 192 __gthread_set_tls_data (0); | |
| 193 #else | |
| 194 __gthread_set_tsd_data (tcb, 0); | |
| 195 #endif | |
| 196 } | |
| 197 } | |
| 198 | |
| 199 /* Initialize global data used by the TLS system. */ | |
| 200 static void | |
| 201 tls_init (void) | |
| 202 { | |
| 203 __GTHREAD_MUTEX_INIT_FUNCTION (&tls_lock); | |
| 204 } | |
| 205 | |
| 206 static void tls_destructor (void) __attribute__ ((destructor)); | |
| 207 static void | |
| 208 tls_destructor (void) | |
| 209 { | |
| 210 #ifdef __RTP__ | |
| 211 /* All threads but this one should have exited by now. */ | |
| 212 tls_delete_hook (NULL); | |
| 213 #endif | |
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214 /* Unregister the hook. */ |
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215 if (delete_hook_installed) |
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216 taskDeleteHookDelete ((FUNCPTR)tls_delete_hook); |
| 0 | 217 |
| 218 if (tls_init_guard.done && __gthread_mutex_lock (&tls_lock) != ERROR) | |
| 219 semDelete (tls_lock); | |
| 220 } | |
| 221 | |
| 222 /* External interface */ | |
| 223 | |
| 224 /* Store in KEYP a value which can be passed to __gthread_setspecific/ | |
| 225 __gthread_getspecific to store and retrieve a value which is | |
| 226 specific to each calling thread. If DTOR is not NULL, it will be | |
| 227 called when a thread terminates with a non-NULL specific value for | |
| 228 this key, with the value as its sole argument. */ | |
| 229 | |
| 230 int | |
| 231 __gthread_key_create (__gthread_key_t *keyp, tls_dtor dtor) | |
| 232 { | |
| 233 __gthread_key_t key; | |
| 234 | |
| 235 __gthread_once (&tls_init_guard, tls_init); | |
| 236 | |
| 237 if (__gthread_mutex_lock (&tls_lock) == ERROR) | |
| 238 return errno; | |
| 239 | |
| 240 for (key = 0; key < MAX_KEYS; key++) | |
| 241 if (!KEY_VALID_P (key)) | |
| 242 goto found_slot; | |
| 243 | |
| 244 /* no room */ | |
| 245 __gthread_mutex_unlock (&tls_lock); | |
| 246 return EAGAIN; | |
| 247 | |
| 248 found_slot: | |
| 249 tls_keys.generation[key]++; /* making it even */ | |
| 250 tls_keys.dtor[key] = dtor; | |
| 251 *keyp = key; | |
| 252 __gthread_mutex_unlock (&tls_lock); | |
| 253 return 0; | |
| 254 } | |
| 255 | |
| 256 /* Invalidate KEY; it can no longer be used as an argument to | |
| 257 setspecific/getspecific. Note that this does NOT call destructor | |
| 258 functions for any live values for this key. */ | |
| 259 int | |
| 260 __gthread_key_delete (__gthread_key_t key) | |
| 261 { | |
| 262 if (key >= MAX_KEYS) | |
| 263 return EINVAL; | |
| 264 | |
| 265 __gthread_once (&tls_init_guard, tls_init); | |
| 266 | |
| 267 if (__gthread_mutex_lock (&tls_lock) == ERROR) | |
| 268 return errno; | |
| 269 | |
| 270 if (!KEY_VALID_P (key)) | |
| 271 { | |
| 272 __gthread_mutex_unlock (&tls_lock); | |
| 273 return EINVAL; | |
| 274 } | |
| 275 | |
| 276 tls_keys.generation[key]++; /* making it odd */ | |
| 277 tls_keys.dtor[key] = 0; | |
| 278 | |
| 279 __gthread_mutex_unlock (&tls_lock); | |
| 280 return 0; | |
| 281 } | |
| 282 | |
| 283 /* Retrieve the thread-specific value for KEY. If it has never been | |
| 284 set in this thread, or KEY is invalid, returns NULL. | |
| 285 | |
| 286 It does not matter if this function races with key_create or | |
| 287 key_delete; the worst that can happen is you get a value other than | |
| 288 the one that a serialized implementation would have provided. */ | |
| 289 | |
| 290 void * | |
| 291 __gthread_getspecific (__gthread_key_t key) | |
| 292 { | |
| 293 struct tls_data *data; | |
| 294 | |
| 295 if (key >= MAX_KEYS) | |
| 296 return 0; | |
| 297 | |
| 298 data = __gthread_get_tls_data (); | |
| 299 | |
| 300 if (!data) | |
| 301 return 0; | |
| 302 | |
| 303 if (data->generation[key] != tls_keys.generation[key]) | |
| 304 return 0; | |
| 305 | |
| 306 return data->values[key]; | |
| 307 } | |
| 308 | |
| 309 /* Set the thread-specific value for KEY. If KEY is invalid, or | |
| 310 memory allocation fails, returns -1, otherwise 0. | |
| 311 | |
| 312 The generation count protects this function against races with | |
| 313 key_create/key_delete; the worst thing that can happen is that a | |
| 314 value is successfully stored into a dead generation (and then | |
| 315 immediately becomes invalid). However, we do have to make sure | |
| 316 to read tls_keys.generation[key] atomically. */ | |
| 317 | |
| 318 int | |
| 319 __gthread_setspecific (__gthread_key_t key, void *value) | |
| 320 { | |
| 321 struct tls_data *data; | |
| 322 unsigned int generation; | |
| 323 | |
| 324 if (key >= MAX_KEYS) | |
| 325 return EINVAL; | |
| 326 | |
| 327 data = __gthread_get_tls_data (); | |
| 328 if (!data) | |
| 329 { | |
|
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330 if (!delete_hook_installed) |
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331 { |
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332 /* Install the delete hook. */ |
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333 if (__gthread_mutex_lock (&tls_lock) == ERROR) |
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334 return ENOMEM; |
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335 if (!delete_hook_installed) |
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336 { |
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337 taskDeleteHookAdd ((FUNCPTR)tls_delete_hook); |
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338 delete_hook_installed = 1; |
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339 } |
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340 __gthread_mutex_unlock (&tls_lock); |
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341 } |
| 0 | 342 |
| 343 data = malloc (sizeof (struct tls_data)); | |
| 344 if (!data) | |
| 345 return ENOMEM; | |
| 346 | |
| 347 memset (data, 0, sizeof (struct tls_data)); | |
| 348 data->owner = &self_owner; | |
| 349 __gthread_set_tls_data (data); | |
| 350 } | |
| 351 | |
| 352 generation = tls_keys.generation[key]; | |
| 353 | |
| 354 if (generation & 1) | |
| 355 return EINVAL; | |
| 356 | |
| 357 data->generation[key] = generation; | |
| 358 data->values[key] = value; | |
| 359 | |
| 360 return 0; | |
| 361 } | |
| 362 #endif /* __GTHREADS */ |