lib/librte_eal/linuxapp/eal/eal_interrupts.c

   1 /*-
   2  *   BSD LICENSE
   3  *
   4  *   Copyright(c) 2010-2012 Intel Corporation. All rights reserved.
   5  *   All rights reserved.
   6  *
   7  *   Redistribution and use in source and binary forms, with or without
   8  *   modification, are permitted provided that the following conditions
   9  *   are met:
  10  *
  11  *     * Redistributions of source code must retain the above copyright
  12  *       notice, this list of conditions and the following disclaimer.
  13  *     * Redistributions in binary form must reproduce the above copyright
  14  *       notice, this list of conditions and the following disclaimer in
  15  *       the documentation and/or other materials provided with the
  16  *       distribution.
  17  *     * Neither the name of Intel Corporation nor the names of its
  18  *       contributors may be used to endorse or promote products derived
  19  *       from this software without specific prior written permission.
  20  *
  21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  27  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  *
  33  */
  34
  35 #include <stdio.h>
  36 #include <stdint.h>
  37 #include <stdlib.h>
  38 #include <pthread.h>
  39 #include <sys/queue.h>
  40 #include <malloc.h>
  41 #include <stdarg.h>
  42 #include <unistd.h>
  43 #include <string.h>
  44 #include <errno.h>
  45 #include <inttypes.h>
  46 #include <sys/epoll.h>
  47 #include <sys/signalfd.h>
  48
  49 #include <rte_common.h>
  50 #include <rte_interrupts.h>
  51 #include <rte_memory.h>
  52 #include <rte_memzone.h>
  53 #include <rte_launch.h>
  54 #include <rte_tailq.h>
  55 #include <rte_eal.h>
  56 #include <rte_per_lcore.h>
  57 #include <rte_lcore.h>
  58 #include <rte_atomic.h>
  59 #include <rte_branch_prediction.h>
  60 #include <rte_ring.h>
  61 #include <rte_debug.h>
  62 #include <rte_log.h>
  63 #include <rte_mempool.h>
  64 #include <rte_pci.h>
  65 #include <rte_malloc.h>
  66 #include <rte_errno.h>
  67 #include <rte_spinlock.h>
  68
  69 #include "eal_private.h"
  70
  71 #define EAL_INTR_EPOLL_WAIT_FOREVER (-1)
  72
  73 /**
  74  * union for pipe fds.
  75  */
  76 union intr_pipefds{
  77         struct {
  78                 int pipefd[2];
  79         };
  80         struct {
  81                 int readfd;
  82                 int writefd;
  83         };
  84 };
  85
  86 /**
  87  * union buffer for reading on different devices
  88  */
  89 union rte_intr_read_buffer {
  90         int uio_intr_count;              /* for uio device */
  91         uint64_t timerfd_num;            /* for timerfd */
  92         char charbuf[16];                /* for others */
  93 };
  94
  95 TAILQ_HEAD(rte_intr_cb_list, rte_intr_callback);
  96 TAILQ_HEAD(rte_intr_source_list, rte_intr_source);
  97
  98 struct rte_intr_callback {
  99         TAILQ_ENTRY(rte_intr_callback) next;
 100         rte_intr_callback_fn cb_fn;  /**< callback address */
 101         void *cb_arg;                /**< parameter for callback */
 102 };
 103
 104 struct rte_intr_source {
 105         TAILQ_ENTRY(rte_intr_source) next;
 106         struct rte_intr_handle intr_handle; /**< interrupt handle */
 107         struct rte_intr_cb_list callbacks;  /**< user callbacks */
 108 };
 109
 110 /* global spinlock for interrupt data operation */
 111 static rte_spinlock_t intr_lock = RTE_SPINLOCK_INITIALIZER;
 112
 113 /* union buffer for pipe read/write */
 114 static union intr_pipefds intr_pipe;
 115
 116 /* interrupt sources list */
 117 static struct rte_intr_source_list intr_sources;
 118
 119 /* interrupt handling thread */
 120 static pthread_t intr_thread;
 121
 122 int
 123 rte_intr_callback_register(struct rte_intr_handle *intr_handle,
 124                         rte_intr_callback_fn cb, void *cb_arg)
 125 {
 126         int ret = -1;
 127         struct rte_intr_source *src;
 128         int wake_thread = 0;
 129
 130         /* first do parameter checking */
 131         if (intr_handle == NULL || intr_handle->fd < 0 || cb == NULL) {
 132                 RTE_LOG(ERR, EAL,
 133                         "Registering with invalid input parameter\n");
 134                 return -EINVAL;
 135         }
 136
 137         /* allocate a new interrupt callback entity */
 138         struct rte_intr_callback *callback =
 139                 rte_zmalloc("interrupt callback list",
 140                                 sizeof(*callback), 0);
 141         if (callback == NULL) {
 142                 RTE_LOG(ERR, EAL, "Can not allocate memory\n");
 143                 return -ENOMEM;
 144         }
 145         callback->cb_fn = cb;
 146         callback->cb_arg = cb_arg;
 147
 148         rte_spinlock_lock(&intr_lock);
 149
 150         /* check if there is at least one callback registered for the fd */
 151         TAILQ_FOREACH(src, &intr_sources, next)
 152         if (src->intr_handle.fd == intr_handle->fd) {
 153                 if (src->callbacks.tqh_first == NULL)
 154                         /* we had no interrupts for this */
 155                         wake_thread = 1;
 156
 157                 TAILQ_INSERT_TAIL(&(src->callbacks), callback, next);
 158                 break;
 159         }
 160
 161         /* No callback registered for this fd */
 162         if (src == NULL){
 163                 /* no existing callbacks for this - add new source */
 164                 src = rte_zmalloc("interrupt source list", sizeof(*src), 0);
 165                 if (src == NULL){
 166                         RTE_LOG(ERR, EAL, "Can not allocate memory\n");
 167                         ret = -ENOMEM;
 168                         goto error;
 169                 }
 170                 src->intr_handle = *intr_handle;
 171                 TAILQ_INIT(&src->callbacks);
 172
 173                 TAILQ_INSERT_TAIL(&intr_sources, src, next);
 174                 TAILQ_INSERT_TAIL(&(src->callbacks), callback, next);
 175                 wake_thread = 1;
 176         }
 177
 178         rte_spinlock_unlock(&intr_lock);
 179         /**
 180          * check if need to notify the pipe fd waited by epoll_wait to
 181          * rebuild the wait list.
 182          */
 183         if (wake_thread)
 184                 if (write(intr_pipe.writefd, "1", 1) < 0)
 185                         return -EPIPE;
 186
 187         return 0;
 188
 189 error:
 190         rte_spinlock_unlock(&intr_lock);
 191
 192         return ret;
 193 }
 194
 195 int
 196 rte_intr_callback_unregister(struct rte_intr_handle *intr_handle,
 197                         rte_intr_callback_fn cb_fn, void *cb_arg)
 198 {
 199         int ret = -1;
 200         struct rte_intr_source *src;
 201         struct rte_intr_callback *cb;
 202
 203         /* do parameter checking first */
 204         if (intr_handle == NULL || intr_handle->fd < 0) {
 205                 RTE_LOG(ERR, EAL,
 206                 "Unregistering with invalid input parameter\n");
 207                 return -EINVAL;
 208         }
 209
 210         rte_spinlock_lock(&intr_lock);
 211
 212         /* check if the insterrupt source for the fd is existent */
 213         TAILQ_FOREACH(src, &intr_sources, next)
 214                 if (src->intr_handle.fd == intr_handle->fd)
 215                         break;
 216
 217         /* No interrupt source registered for the fd */
 218         if (src == NULL) {
 219                 ret = -ENOENT;
 220                 goto error;
 221         }
 222
 223         ret = 0;
 224         TAILQ_FOREACH(cb, &src->callbacks, next) {
 225                 if (cb->cb_fn != cb_fn)
 226                         continue;
 227                 if (cb_arg == (void *)-1 || cb->cb_arg == cb_arg) {
 228                         TAILQ_REMOVE(&src->callbacks, cb, next);
 229                         rte_free(cb);
 230                         ret ++;
 231                 }
 232
 233                 if (src->callbacks.tqh_first == NULL) {
 234                         TAILQ_REMOVE(&intr_sources, src, next);
 235                         rte_free(src);
 236                 }
 237         }
 238
 239         /* notify the pipe fd waited by epoll_wait to rebuild the wait list */
 240         if (write(intr_pipe.writefd, "1", 1) < 0) {
 241                 ret = -EPIPE;
 242                 goto error;
 243         }
 244
 245         rte_spinlock_unlock(&intr_lock);
 246
 247         return ret;
 248
 249 error:
 250         rte_spinlock_unlock(&intr_lock);
 251
 252         return ret;
 253 }
 254
 255 int
 256 rte_intr_enable(struct rte_intr_handle *intr_handle)
 257 {
 258         const int value = 1;
 259
 260         if (!intr_handle || intr_handle->fd < 0)
 261                 return -1;
 262
 263         switch (intr_handle->type){
 264         /* write to the uio fd to enable the interrupt */
 265         case RTE_INTR_HANDLE_UIO:
 266                 if (write(intr_handle->fd, &value, sizeof(value)) < 0) {
 267                         RTE_LOG(ERR, EAL,
 268                                 "Error enabling interrupts for fd %d\n",
 269                                                         intr_handle->fd);
 270                         return -1;
 271                 }
 272                 break;
 273         /* not used at this moment */
 274         case RTE_INTR_HANDLE_ALARM:
 275                 return -1;
 276         /* unkown handle type */
 277         default:
 278                 RTE_LOG(ERR, EAL,
 279                         "Unknown handle type of fd %d\n",
 280                                         intr_handle->fd);
 281                 return -1;
 282         }
 283
 284         return 0;
 285 }
 286
 287 int
 288 rte_intr_disable(struct rte_intr_handle *intr_handle)
 289 {
 290         const int value = 0;
 291
 292         if (!intr_handle || intr_handle->fd < 0)
 293                 return -1;
 294
 295         switch (intr_handle->type){
 296         /* write to the uio fd to disable the interrupt */
 297         case RTE_INTR_HANDLE_UIO:
 298                 if (write(intr_handle->fd, &value, sizeof(value)) < 0){
 299                         RTE_LOG(ERR, EAL,
 300                                 "Error enabling interrupts for fd %d\n",
 301                                                         intr_handle->fd);
 302                         return -1;
 303                 }
 304                 break;
 305         /* not used at this moment */
 306         case RTE_INTR_HANDLE_ALARM:
 307                 return -1;
 308         /* unkown handle type */
 309         default:
 310                 RTE_LOG(ERR, EAL,
 311                         "Unknown handle type of fd %d\n",
 312                                         intr_handle->fd);
 313                 return -1;
 314         }
 315
 316         return 0;
 317 }
 318
 319 static int
 320 eal_intr_process_interrupts(struct epoll_event *events, int nfds)
 321 {
 322         int n, i, active_cb, bytes_read;
 323         struct rte_intr_source *src;
 324         struct rte_intr_callback *cb;
 325         union rte_intr_read_buffer buf;
 326         struct rte_intr_callback active_cbs[32];
 327
 328         for (n = 0; n < nfds; n++) {
 329                 /**
 330                  * if the pipe fd is ready to read, return out to
 331                  * rebuild the wait list.
 332                  */
 333                 if (events[n].data.fd == intr_pipe.readfd){
 334                         int r = read(intr_pipe.readfd, buf.charbuf,
 335                                         sizeof(buf.charbuf));
 336                         RTE_SET_USED(r);
 337                         return -1;
 338                 }
 339                 rte_spinlock_lock(&intr_lock);
 340                 TAILQ_FOREACH(src, &intr_sources, next)
 341                         if (src->intr_handle.fd ==
 342                                         events[n].data.fd)
 343                                 break;
 344                 if (src == NULL){
 345                         rte_spinlock_unlock(&intr_lock);
 346                         continue;
 347                 }
 348
 349                 /* for this source, make a copy of all the callbacks,
 350                  * then unlock the lock, so the callbacks can
 351                  * themselves manipulate the list for future
 352                  * instances.
 353                  */
 354                 active_cb = 0;
 355                 memset(active_cbs, 0, sizeof(active_cbs));
 356                 TAILQ_FOREACH(cb, &src->callbacks, next)
 357                         active_cbs[active_cb++] = *cb;
 358                 rte_spinlock_unlock(&intr_lock);
 359
 360                 /* set the length to be read dor different handle type */
 361                 switch (src->intr_handle.type) {
 362                 case RTE_INTR_HANDLE_UIO:
 363                         bytes_read = 4;
 364                         break;
 365                 case RTE_INTR_HANDLE_ALARM:
 366                         bytes_read = sizeof(uint64_t);
 367                         break;
 368                 default:
 369                         bytes_read = 1;
 370                         break;
 371                 }
 372                 /**
 373                  * read out to clear the ready-to-be-read flag
 374                  * for epoll_wait.
 375                  */
 376                 bytes_read = read(events[n].data.fd, &buf, bytes_read);
 377                 if (bytes_read < 0) {
 378                         RTE_LOG(ERR, EAL, "Error reading from file descriptor"
 379                                 " %d, error: %d\n", events[n].data.fd, errno);
 380                         continue;
 381                 }
 382                 else if (bytes_read == 0) {
 383                         RTE_LOG(ERR, EAL,
 384                                 "Read nothing from file descriptor %d.\n",
 385                                                         events[n].data.fd);
 386                         continue;
 387                 }
 388                 /**
 389                  * Finally, call all callbacks from the copy
 390                  * we made earlier.
 391                  */
 392                 for (i = 0; i < active_cb; i++) {
 393                         if (active_cbs[i].cb_fn == NULL)
 394                                 continue;
 395                         active_cbs[i].cb_fn(&src->intr_handle,
 396                                         active_cbs[i].cb_arg);
 397                 }
 398         }
 399
 400         return 0;
 401 }
 402
 403 /**
 404  * It handles all the interrupts.
 405  *
 406  * @param pfd
 407  *  epoll file descriptor.
 408  * @param totalfds
 409  *  The number of file descriptors added in epoll.
 410  *
 411  * @return
 412  *  void
 413  */
 414 static void
 415 eal_intr_handle_interrupts(int pfd, unsigned totalfds)
 416 {
 417         struct epoll_event events[totalfds];
 418         int nfds = 0;
 419
 420         for(;;) {
 421                 nfds = epoll_wait(pfd, events, totalfds,
 422                         EAL_INTR_EPOLL_WAIT_FOREVER);
 423                 /* epoll_wait fail */
 424                 if (nfds < 0) {
 425                         if (errno == EINTR)
 426                                 continue;
 427                         RTE_LOG(ERR, EAL,
 428                                 "epoll_wait returns with fail\n");
 429                         return;
 430                 }
 431                 /* epoll_wait timeout, will never happens here */
 432                 else if (nfds == 0)
 433                         continue;
 434                 /* epoll_wait has at least one fd ready to read */
 435                 if (eal_intr_process_interrupts(events, nfds) < 0)
 436                         return;
 437         }
 438 }
 439
 440 /**
 441  * It builds/rebuilds up the epoll file descriptor with all the
 442  * file descriptors being waited on. Then handles the interrupts.
 443  *
 444  * @param arg
 445  *  pointer. (unused)
 446  *
 447  * @return
 448  *  never return;
 449  */
 450 static __attribute__((noreturn)) void *
 451 eal_intr_thread_main(__rte_unused void *arg)
 452 {
 453         struct epoll_event ev;
 454
 455         /* host thread, never break out */
 456         for (;;) {
 457                 /* build up the epoll fd with all descriptors we are to
 458                  * wait on then pass it to the handle_interrupts function
 459                  */
 460                 static struct epoll_event pipe_event = {
 461                         .events = EPOLLIN | EPOLLPRI,
 462                 };
 463                 struct rte_intr_source *src;
 464                 unsigned numfds = 0;
 465
 466                 /* create epoll fd */
 467                 int pfd = epoll_create(1);
 468                 if (pfd < 0)
 469                         rte_panic("Cannot create epoll instance\n");
 470
 471                 pipe_event.data.fd = intr_pipe.readfd;
 472                 /**
 473                  * add pipe fd into wait list, this pipe is used to
 474                  * rebuild the wait list.
 475                  */
 476                 if (epoll_ctl(pfd, EPOLL_CTL_ADD, intr_pipe.readfd,
 477                                                 &pipe_event) < 0) {
 478                         rte_panic("Error adding fd to %d epoll_ctl, %s\n",
 479                                         intr_pipe.readfd, strerror(errno));
 480                 }
 481                 numfds++;
 482
 483                 rte_spinlock_lock(&intr_lock);
 484
 485                 TAILQ_FOREACH(src, &intr_sources, next) {
 486                         if (src->callbacks.tqh_first == NULL)
 487                                 continue; /* skip those with no callbacks */
 488                         ev.events = EPOLLIN | EPOLLPRI;
 489                         ev.data.fd = src->intr_handle.fd;
 490
 491                         /**
 492                          * add all the uio device file descriptor
 493                          * into wait list.
 494                          */
 495                         if (epoll_ctl(pfd, EPOLL_CTL_ADD,
 496                                         src->intr_handle.fd, &ev) < 0){
 497                                 rte_panic("Error adding fd %d epoll_ctl, %s\n",
 498                                         src->intr_handle.fd, strerror(errno));
 499                         }
 500                         else
 501                                 numfds++;
 502                 }
 503                 rte_spinlock_unlock(&intr_lock);
 504                 /* serve the interrupt */
 505                 eal_intr_handle_interrupts(pfd, numfds);
 506
 507                 /**
 508                  * when we return, we need to rebuild the
 509                  * list of fds to monitor.
 510                  */
 511                 close(pfd);
 512         }
 513 }
 514
 515 int
 516 rte_eal_intr_init(void)
 517 {
 518         int ret = 0;
 519
 520         /* init the global interrupt source head */
 521         TAILQ_INIT(&intr_sources);
 522
 523         /**
 524          * create a pipe which will be waited by epoll and notified to
 525          * rebuild the wait list of epoll.
 526          */
 527         if (pipe(intr_pipe.pipefd) < 0)
 528                 return -1;
 529
 530         /* create the host thread to wait/handle the interrupt */
 531         ret = pthread_create(&intr_thread, NULL,
 532                         eal_intr_thread_main, NULL);
 533         if (ret != 0)
 534                 RTE_LOG(ERR, EAL,
 535                         "Failed to create thread for interrupt handling\n");
 536
 537         return -ret;
 538 }
 539