lib/eal/linux/eal_dev.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2018 Intel Corporation
   3  */
   4
   5 #include <string.h>
   6 #include <unistd.h>
   7 #include <fcntl.h>
   8 #include <signal.h>
   9 #include <sys/socket.h>
  10 #include <linux/netlink.h>
  11
  12 #include <rte_string_fns.h>
  13 #include <rte_log.h>
  14 #include <rte_compat.h>
  15 #include <rte_dev.h>
  16 #include <rte_malloc.h>
  17 #include <rte_interrupts.h>
  18 #include <rte_alarm.h>
  19 #include <rte_bus.h>
  20 #include <rte_eal.h>
  21 #include <rte_spinlock.h>
  22 #include <rte_errno.h>
  23
  24 #include "eal_private.h"
  25
  26 static struct rte_intr_handle *intr_handle;
  27 static rte_rwlock_t monitor_lock = RTE_RWLOCK_INITIALIZER;
  28 static uint32_t monitor_refcount;
  29 static bool hotplug_handle;
  30
  31 #define EAL_UEV_MSG_LEN 4096
  32 #define EAL_UEV_MSG_ELEM_LEN 128
  33
  34 /*
  35  * spinlock for device hot-unplug failure handling. If it try to access bus or
  36  * device, such as handle sigbus on bus or handle memory failure for device
  37  * just need to use this lock. It could protect the bus and the device to avoid
  38  * race condition.
  39  */
  40 static rte_spinlock_t failure_handle_lock = RTE_SPINLOCK_INITIALIZER;
  41
  42 static struct sigaction sigbus_action_old;
  43
  44 static int sigbus_need_recover;
  45
  46 static void dev_uev_handler(__rte_unused void *param);
  47
  48 /* identify the system layer which reports this event. */
  49 enum eal_dev_event_subsystem {
  50         EAL_DEV_EVENT_SUBSYSTEM_PCI, /* PCI bus device event */
  51         EAL_DEV_EVENT_SUBSYSTEM_UIO, /* UIO driver device event */
  52         EAL_DEV_EVENT_SUBSYSTEM_VFIO, /* VFIO driver device event */
  53         EAL_DEV_EVENT_SUBSYSTEM_MAX
  54 };
  55
  56 static void
  57 sigbus_action_recover(void)
  58 {
  59         if (sigbus_need_recover) {
  60                 sigaction(SIGBUS, &sigbus_action_old, NULL);
  61                 sigbus_need_recover = 0;
  62         }
  63 }
  64
  65 static void sigbus_handler(int signum, siginfo_t *info,
  66                                 void *ctx __rte_unused)
  67 {
  68         int ret;
  69
  70         RTE_LOG(DEBUG, EAL, "Thread catch SIGBUS, fault address:%p\n",
  71                 info->si_addr);
  72
  73         rte_spinlock_lock(&failure_handle_lock);
  74         ret = rte_bus_sigbus_handler(info->si_addr);
  75         rte_spinlock_unlock(&failure_handle_lock);
  76         if (ret == -1) {
  77                 rte_exit(EXIT_FAILURE,
  78                          "Failed to handle SIGBUS for hot-unplug, "
  79                          "(rte_errno: %s)!", strerror(rte_errno));
  80         } else if (ret == 1) {
  81                 if (sigbus_action_old.sa_flags == SA_SIGINFO
  82                     && sigbus_action_old.sa_sigaction) {
  83                         (*(sigbus_action_old.sa_sigaction))(signum,
  84                                                             info, ctx);
  85                 } else if (sigbus_action_old.sa_flags != SA_SIGINFO
  86                            && sigbus_action_old.sa_handler) {
  87                         (*(sigbus_action_old.sa_handler))(signum);
  88                 } else {
  89                         rte_exit(EXIT_FAILURE,
  90                                  "Failed to handle generic SIGBUS!");
  91                 }
  92         }
  93
  94         RTE_LOG(DEBUG, EAL, "Success to handle SIGBUS for hot-unplug!\n");
  95 }
  96
  97 static int cmp_dev_name(const struct rte_device *dev,
  98         const void *_name)
  99 {
 100         const char *name = _name;
 101
 102         return strcmp(dev->name, name);
 103 }
 104
 105 static int
 106 dev_uev_socket_fd_create(void)
 107 {
 108         struct sockaddr_nl addr;
 109         int ret, fd;
 110
 111         fd = socket(PF_NETLINK, SOCK_RAW | SOCK_CLOEXEC | SOCK_NONBLOCK,
 112                     NETLINK_KOBJECT_UEVENT);
 113         if (fd < 0) {
 114                 RTE_LOG(ERR, EAL, "create uevent fd failed.\n");
 115                 return -1;
 116         }
 117
 118         memset(&addr, 0, sizeof(addr));
 119         addr.nl_family = AF_NETLINK;
 120         addr.nl_pid = 0;
 121         addr.nl_groups = 0xffffffff;
 122
 123         ret = bind(fd, (struct sockaddr *) &addr, sizeof(addr));
 124         if (ret < 0) {
 125                 RTE_LOG(ERR, EAL, "Failed to bind uevent socket.\n");
 126                 goto err;
 127         }
 128
 129         if (rte_intr_fd_set(intr_handle, fd))
 130                 goto err;
 131
 132         return 0;
 133 err:
 134         close(fd);
 135         fd = -1;
 136         return ret;
 137 }
 138
 139 struct rte_dev_event {
 140         enum rte_dev_event_type type;   /**< device event type */
 141         int subsystem;                  /**< subsystem id */
 142         char *devname;                  /**< device name */
 143 };
 144
 145 static int
 146 dev_uev_parse(const char *buf, struct rte_dev_event *event, int length)
 147 {
 148         char action[EAL_UEV_MSG_ELEM_LEN];
 149         char subsystem[EAL_UEV_MSG_ELEM_LEN];
 150         char pci_slot_name[EAL_UEV_MSG_ELEM_LEN];
 151         int i = 0;
 152
 153         memset(action, 0, EAL_UEV_MSG_ELEM_LEN);
 154         memset(subsystem, 0, EAL_UEV_MSG_ELEM_LEN);
 155         memset(pci_slot_name, 0, EAL_UEV_MSG_ELEM_LEN);
 156
 157         while (i < length) {
 158                 for (; i < length; i++) {
 159                         if (*buf)
 160                                 break;
 161                         buf++;
 162                 }
 163                 /**
 164                  * check device uevent from kernel side, no need to check
 165                  * uevent from udev.
 166                  */
 167                 if (!strncmp(buf, "libudev", 7)) {
 168                         buf += 7;
 169                         i += 7;
 170                         return -1;
 171                 }
 172                 if (!strncmp(buf, "ACTION=", 7)) {
 173                         buf += 7;
 174                         i += 7;
 175                         strlcpy(action, buf, sizeof(action));
 176                 } else if (!strncmp(buf, "SUBSYSTEM=", 10)) {
 177                         buf += 10;
 178                         i += 10;
 179                         strlcpy(subsystem, buf, sizeof(subsystem));
 180                 } else if (!strncmp(buf, "PCI_SLOT_NAME=", 14)) {
 181                         buf += 14;
 182                         i += 14;
 183                         strlcpy(pci_slot_name, buf, sizeof(subsystem));
 184                         event->devname = strdup(pci_slot_name);
 185                 }
 186                 for (; i < length; i++) {
 187                         if (*buf == '\0')
 188                                 break;
 189                         buf++;
 190                 }
 191         }
 192
 193         /* parse the subsystem layer */
 194         if (!strncmp(subsystem, "uio", 3))
 195                 event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_UIO;
 196         else if (!strncmp(subsystem, "pci", 3))
 197                 event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_PCI;
 198         else if (!strncmp(subsystem, "vfio", 4))
 199                 event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_VFIO;
 200         else
 201                 goto err;
 202
 203         /* parse the action type */
 204         if (!strncmp(action, "add", 3))
 205                 event->type = RTE_DEV_EVENT_ADD;
 206         else if (!strncmp(action, "remove", 6))
 207                 event->type = RTE_DEV_EVENT_REMOVE;
 208         else
 209                 goto err;
 210         return 0;
 211 err:
 212         free(event->devname);
 213         return -1;
 214 }
 215
 216 static void
 217 dev_delayed_unregister(void *param)
 218 {
 219         rte_intr_callback_unregister(intr_handle, dev_uev_handler, param);
 220         close(rte_intr_fd_get(intr_handle));
 221         rte_intr_fd_set(intr_handle, -1);
 222 }
 223
 224 static void
 225 dev_uev_handler(__rte_unused void *param)
 226 {
 227         struct rte_dev_event uevent;
 228         int ret;
 229         char buf[EAL_UEV_MSG_LEN];
 230         struct rte_bus *bus;
 231         struct rte_device *dev;
 232         const char *busname = "";
 233
 234         memset(&uevent, 0, sizeof(struct rte_dev_event));
 235         memset(buf, 0, EAL_UEV_MSG_LEN);
 236
 237         ret = recv(rte_intr_fd_get(intr_handle), buf, EAL_UEV_MSG_LEN,
 238                    MSG_DONTWAIT);
 239         if (ret < 0 && errno == EAGAIN)
 240                 return;
 241         else if (ret <= 0) {
 242                 /* connection is closed or broken, can not up again. */
 243                 RTE_LOG(ERR, EAL, "uevent socket connection is broken.\n");
 244                 rte_eal_alarm_set(1, dev_delayed_unregister, NULL);
 245                 return;
 246         }
 247
 248         ret = dev_uev_parse(buf, &uevent, EAL_UEV_MSG_LEN);
 249         if (ret < 0) {
 250                 RTE_LOG(DEBUG, EAL, "Ignoring uevent '%s'\n", buf);
 251                 return;
 252         }
 253
 254         RTE_LOG(DEBUG, EAL, "receive uevent(name:%s, type:%d, subsystem:%d)\n",
 255                 uevent.devname, uevent.type, uevent.subsystem);
 256
 257         switch (uevent.subsystem) {
 258         case EAL_DEV_EVENT_SUBSYSTEM_PCI:
 259         case EAL_DEV_EVENT_SUBSYSTEM_UIO:
 260                 busname = "pci";
 261                 break;
 262         default:
 263                 break;
 264         }
 265
 266         if (uevent.devname) {
 267                 if (uevent.type == RTE_DEV_EVENT_REMOVE && hotplug_handle) {
 268                         rte_spinlock_lock(&failure_handle_lock);
 269                         bus = rte_bus_find_by_name(busname);
 270                         if (bus == NULL) {
 271                                 RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n",
 272                                         busname);
 273                                 goto failure_handle_err;
 274                         }
 275
 276                         dev = bus->find_device(NULL, cmp_dev_name,
 277                                                uevent.devname);
 278                         if (dev == NULL) {
 279                                 RTE_LOG(ERR, EAL, "Cannot find device (%s) on "
 280                                         "bus (%s)\n", uevent.devname, busname);
 281                                 goto failure_handle_err;
 282                         }
 283
 284                         ret = bus->hot_unplug_handler(dev);
 285                         if (ret) {
 286                                 RTE_LOG(ERR, EAL, "Can not handle hot-unplug "
 287                                         "for device (%s)\n", dev->name);
 288                         }
 289                         rte_spinlock_unlock(&failure_handle_lock);
 290                 }
 291                 rte_dev_event_callback_process(uevent.devname, uevent.type);
 292                 free(uevent.devname);
 293         }
 294
 295         return;
 296
 297 failure_handle_err:
 298         rte_spinlock_unlock(&failure_handle_lock);
 299         free(uevent.devname);
 300 }
 301
 302 int
 303 rte_dev_event_monitor_start(void)
 304 {
 305         int ret = 0;
 306
 307         rte_rwlock_write_lock(&monitor_lock);
 308
 309         if (monitor_refcount) {
 310                 monitor_refcount++;
 311                 goto exit;
 312         }
 313
 314         intr_handle = rte_intr_instance_alloc(RTE_INTR_INSTANCE_F_PRIVATE);
 315         if (intr_handle == NULL) {
 316                 RTE_LOG(ERR, EAL, "Fail to allocate intr_handle\n");
 317                 goto exit;
 318         }
 319
 320         if (rte_intr_type_set(intr_handle, RTE_INTR_HANDLE_DEV_EVENT))
 321                 goto exit;
 322
 323         if (rte_intr_fd_set(intr_handle, -1))
 324                 goto exit;
 325
 326         ret = dev_uev_socket_fd_create();
 327         if (ret) {
 328                 RTE_LOG(ERR, EAL, "error create device event fd.\n");
 329                 goto exit;
 330         }
 331
 332         ret = rte_intr_callback_register(intr_handle, dev_uev_handler, NULL);
 333
 334         if (ret) {
 335                 close(rte_intr_fd_get(intr_handle));
 336                 goto exit;
 337         }
 338
 339         monitor_refcount++;
 340
 341 exit:
 342         rte_intr_instance_free(intr_handle);
 343         rte_rwlock_write_unlock(&monitor_lock);
 344         return ret;
 345 }
 346
 347 int
 348 rte_dev_event_monitor_stop(void)
 349 {
 350         int ret = 0;
 351
 352         rte_rwlock_write_lock(&monitor_lock);
 353
 354         if (!monitor_refcount) {
 355                 RTE_LOG(ERR, EAL, "device event monitor already stopped\n");
 356                 goto exit;
 357         }
 358
 359         if (monitor_refcount > 1) {
 360                 monitor_refcount--;
 361                 goto exit;
 362         }
 363
 364         ret = rte_intr_callback_unregister(intr_handle, dev_uev_handler,
 365                                            (void *)-1);
 366         if (ret < 0) {
 367                 RTE_LOG(ERR, EAL, "fail to unregister uevent callback.\n");
 368                 goto exit;
 369         }
 370
 371         close(rte_intr_fd_get(intr_handle));
 372         rte_intr_instance_free(intr_handle);
 373
 374         monitor_refcount--;
 375
 376 exit:
 377         rte_rwlock_write_unlock(&monitor_lock);
 378
 379         return ret;
 380 }
 381
 382 int
 383 dev_sigbus_handler_register(void)
 384 {
 385         sigset_t mask;
 386         struct sigaction action;
 387
 388         rte_errno = 0;
 389
 390         if (sigbus_need_recover)
 391                 return 0;
 392
 393         sigemptyset(&mask);
 394         sigaddset(&mask, SIGBUS);
 395         action.sa_flags = SA_SIGINFO;
 396         action.sa_mask = mask;
 397         action.sa_sigaction = sigbus_handler;
 398         sigbus_need_recover = !sigaction(SIGBUS, &action, &sigbus_action_old);
 399
 400         return rte_errno;
 401 }
 402
 403 int
 404 dev_sigbus_handler_unregister(void)
 405 {
 406         rte_errno = 0;
 407
 408         sigbus_action_recover();
 409
 410         return rte_errno;
 411 }
 412
 413 int
 414 rte_dev_hotplug_handle_enable(void)
 415 {
 416         int ret = 0;
 417
 418         ret = dev_sigbus_handler_register();
 419         if (ret < 0)
 420                 RTE_LOG(ERR, EAL,
 421                         "fail to register sigbus handler for devices.\n");
 422
 423         hotplug_handle = true;
 424
 425         return ret;
 426 }
 427
 428 int
 429 rte_dev_hotplug_handle_disable(void)
 430 {
 431         int ret = 0;
 432
 433         ret = dev_sigbus_handler_unregister();
 434         if (ret < 0)
 435                 RTE_LOG(ERR, EAL,
 436                         "fail to unregister sigbus handler for devices.\n");
 437
 438         hotplug_handle = false;
 439
 440         return ret;
 441 }