source: mainline/uspace/lib/c/generic/fibril.c@ 0016674

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 0016674 was 38d150e, checked in by Jiri Svoboda <jiri@…>, 8 years ago

Prefer to get memory allocation functions through the standard stdlib header.
  • Property mode set to 100644
File size: 8.7 KB
Line 
1/*
2 * Copyright (c) 2006 Ondrej Palkovsky
3 * Copyright (c) 2007 Jakub Jermar
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * - Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * - Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * - The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30/** @addtogroup libc
31 * @{
32 */
33/** @file
34 */
35
36#include <adt/list.h>
37#include <fibril.h>
38#include <thread.h>
39#include <stack.h>
40#include <tls.h>
41#include <stdlib.h>
42#include <abi/mm/as.h>
43#include <as.h>
44#include <stdio.h>
45#include <libarch/barrier.h>
46#include <libarch/faddr.h>
47#include <futex.h>
48#include <assert.h>
49#include <async.h>
50
51#ifdef FUTEX_UPGRADABLE
52#include <rcu.h>
53#endif
54
55/**
56 * This futex serializes access to ready_list,
57 * manager_list and fibril_list.
58 */
59static futex_t fibril_futex = FUTEX_INITIALIZER;
60
61static LIST_INITIALIZE(ready_list);
62static LIST_INITIALIZE(manager_list);
63static LIST_INITIALIZE(fibril_list);
64
65/** Function that spans the whole life-cycle of a fibril.
66 *
67 * Each fibril begins execution in this function. Then the function implementing
68 * the fibril logic is called. After its return, the return value is saved.
69 * The fibril then switches to another fibril, which cleans up after it.
70 *
71 */
72static void fibril_main(void)
73{
74 fibril_t *fibril = __tcb_get()->fibril_data;
75
76#ifdef FUTEX_UPGRADABLE
77 rcu_register_fibril();
78#endif
79
80 /* Call the implementing function. */
81 fibril->retval = fibril->func(fibril->arg);
82
83 futex_down(&async_futex);
84 fibril_switch(FIBRIL_FROM_DEAD);
85 /* Not reached */
86}
87
88/** Setup fibril information into TCB structure
89 *
90 */
91fibril_t *fibril_setup(void)
92{
93 tcb_t *tcb = tls_make();
94 if (!tcb)
95 return NULL;
96
97 fibril_t *fibril = malloc(sizeof(fibril_t));
98 if (!fibril) {
99 tls_free(tcb);
100 return NULL;
101 }
102
103 tcb->fibril_data = fibril;
104 fibril->tcb = tcb;
105
106 fibril->func = NULL;
107 fibril->arg = NULL;
108 fibril->stack = NULL;
109 fibril->clean_after_me = NULL;
110 fibril->retval = 0;
111 fibril->flags = 0;
112
113 fibril->waits_for = NULL;
114
115 fibril->switches = 0;
116
117 /*
118 * We are called before __tcb_set(), so we need to use
119 * futex_down/up() instead of futex_lock/unlock() that
120 * may attempt to access TLS.
121 */
122 futex_down(&fibril_futex);
123 list_append(&fibril->all_link, &fibril_list);
124 futex_up(&fibril_futex);
125
126 return fibril;
127}
128
129void fibril_teardown(fibril_t *fibril, bool locked)
130{
131 if (!locked)
132 futex_lock(&fibril_futex);
133 list_remove(&fibril->all_link);
134 if (!locked)
135 futex_unlock(&fibril_futex);
136 tls_free(fibril->tcb);
137 free(fibril);
138}
139
140/** Switch from the current fibril.
141 *
142 * If stype is FIBRIL_TO_MANAGER or FIBRIL_FROM_DEAD, the async_futex must
143 * be held.
144 *
145 * @param stype Switch type. One of FIBRIL_PREEMPT, FIBRIL_TO_MANAGER,
146 * FIBRIL_FROM_MANAGER, FIBRIL_FROM_DEAD. The parameter
147 * describes the circumstances of the switch.
148 *
149 * @return 0 if there is no ready fibril,
150 * @return 1 otherwise.
151 *
152 */
153int fibril_switch(fibril_switch_type_t stype)
154{
155 futex_lock(&fibril_futex);
156
157 switch (stype) {
158 case FIBRIL_PREEMPT:
159 case FIBRIL_FROM_MANAGER:
160 if (list_empty(&ready_list)) {
161 futex_unlock(&fibril_futex);
162 return 0;
163 }
164 break;
165 case FIBRIL_TO_MANAGER:
166 case FIBRIL_FROM_DEAD:
167 /* Make sure the async_futex is held. */
168 assert((atomic_signed_t) async_futex.val.count <= 0);
169
170 /* If we are going to manager and none exists, create it */
171 while (list_empty(&manager_list)) {
172 futex_unlock(&fibril_futex);
173 async_create_manager();
174 futex_lock(&fibril_futex);
175 }
176 break;
177 }
178
179 fibril_t *srcf = __tcb_get()->fibril_data;
180 if (stype != FIBRIL_FROM_DEAD) {
181
182 /* Save current state */
183 if (!context_save(&srcf->ctx)) {
184 if (srcf->clean_after_me) {
185 /*
186 * Cleanup after the dead fibril from which we
187 * restored context here.
188 */
189 void *stack = srcf->clean_after_me->stack;
190 if (stack) {
191 /*
192 * This check is necessary because a
193 * thread could have exited like a
194 * normal fibril using the
195 * FIBRIL_FROM_DEAD switch type. In that
196 * case, its fibril will not have the
197 * stack member filled.
198 */
199 as_area_destroy(stack);
200 }
201 fibril_teardown(srcf->clean_after_me, true);
202 srcf->clean_after_me = NULL;
203 }
204
205 return 1; /* futex_unlock already done here */
206 }
207
208 /* Put the current fibril into the correct run list */
209 switch (stype) {
210 case FIBRIL_PREEMPT:
211 list_append(&srcf->link, &ready_list);
212 break;
213 case FIBRIL_FROM_MANAGER:
214 list_append(&srcf->link, &manager_list);
215 break;
216 default:
217 assert(stype == FIBRIL_TO_MANAGER);
218
219 srcf->switches++;
220
221 /*
222 * Don't put the current fibril into any list, it should
223 * already be somewhere, or it will be lost.
224 */
225 break;
226 }
227 }
228
229 fibril_t *dstf;
230
231 /* Choose a new fibril to run */
232 switch (stype) {
233 case FIBRIL_TO_MANAGER:
234 case FIBRIL_FROM_DEAD:
235 dstf = list_get_instance(list_first(&manager_list), fibril_t,
236 link);
237
238 if (stype == FIBRIL_FROM_DEAD)
239 dstf->clean_after_me = srcf;
240 break;
241 default:
242 dstf = list_get_instance(list_first(&ready_list), fibril_t,
243 link);
244 break;
245 }
246
247 list_remove(&dstf->link);
248
249 futex_unlock(&fibril_futex);
250
251#ifdef FUTEX_UPGRADABLE
252 if (stype == FIBRIL_FROM_DEAD) {
253 rcu_deregister_fibril();
254 }
255#endif
256
257 context_restore(&dstf->ctx);
258 /* not reached */
259}
260
261/** Create a new fibril.
262 *
263 * @param func Implementing function of the new fibril.
264 * @param arg Argument to pass to func.
265 * @param stksz Stack size in bytes.
266 *
267 * @return 0 on failure or TLS of the new fibril.
268 *
269 */
270fid_t fibril_create_generic(int (*func)(void *), void *arg, size_t stksz)
271{
272 fibril_t *fibril;
273
274 fibril = fibril_setup();
275 if (fibril == NULL)
276 return 0;
277
278 size_t stack_size = (stksz == FIBRIL_DFLT_STK_SIZE) ?
279 stack_size_get() : stksz;
280 fibril->stack = as_area_create(AS_AREA_ANY, stack_size,
281 AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE | AS_AREA_GUARD |
282 AS_AREA_LATE_RESERVE, AS_AREA_UNPAGED);
283 if (fibril->stack == (void *) -1) {
284 fibril_teardown(fibril, false);
285 return 0;
286 }
287
288 fibril->func = func;
289 fibril->arg = arg;
290
291 context_save(&fibril->ctx);
292 context_set(&fibril->ctx, FADDR(fibril_main), fibril->stack,
293 stack_size, fibril->tcb);
294
295 return (fid_t) fibril;
296}
297
298/** Delete a fibril that has never run.
299 *
300 * Free resources of a fibril that has been created with fibril_create()
301 * but never readied using fibril_add_ready().
302 *
303 * @param fid Pointer to the fibril structure of the fibril to be
304 * added.
305 */
306void fibril_destroy(fid_t fid)
307{
308 fibril_t *fibril = (fibril_t *) fid;
309
310 as_area_destroy(fibril->stack);
311 fibril_teardown(fibril, false);
312}
313
314/** Add a fibril to the ready list.
315 *
316 * @param fid Pointer to the fibril structure of the fibril to be
317 * added.
318 *
319 */
320void fibril_add_ready(fid_t fid)
321{
322 fibril_t *fibril = (fibril_t *) fid;
323
324 futex_lock(&fibril_futex);
325 list_append(&fibril->link, &ready_list);
326 futex_unlock(&fibril_futex);
327}
328
329/** Add a fibril to the manager list.
330 *
331 * @param fid Pointer to the fibril structure of the fibril to be
332 * added.
333 *
334 */
335void fibril_add_manager(fid_t fid)
336{
337 fibril_t *fibril = (fibril_t *) fid;
338
339 futex_lock(&fibril_futex);
340 list_append(&fibril->link, &manager_list);
341 futex_unlock(&fibril_futex);
342}
343
344/** Remove one manager from the manager list. */
345void fibril_remove_manager(void)
346{
347 futex_lock(&fibril_futex);
348 if (!list_empty(&manager_list))
349 list_remove(list_first(&manager_list));
350 futex_unlock(&fibril_futex);
351}
352
353/** Return fibril id of the currently running fibril.
354 *
355 * @return fibril ID of the currently running fibril.
356 *
357 */
358fid_t fibril_get_id(void)
359{
360 return (fid_t) __tcb_get()->fibril_data;
361}
362
363/** @}
364 */
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