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