drivers/firmware/arm_sdei.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2017 Arm Ltd.
   3 #define pr_fmt(fmt) "sdei: " fmt
   4
   5 #include <acpi/ghes.h>
   6 #include <linux/acpi.h>
   7 #include <linux/arm_sdei.h>
   8 #include <linux/arm-smccc.h>
   9 #include <linux/atomic.h>
  10 #include <linux/bitops.h>
  11 #include <linux/compiler.h>
  12 #include <linux/cpuhotplug.h>
  13 #include <linux/cpu.h>
  14 #include <linux/cpu_pm.h>
  15 #include <linux/errno.h>
  16 #include <linux/hardirq.h>
  17 #include <linux/kernel.h>
  18 #include <linux/kprobes.h>
  19 #include <linux/kvm_host.h>
  20 #include <linux/list.h>
  21 #include <linux/mutex.h>
  22 #include <linux/notifier.h>
  23 #include <linux/of.h>
  24 #include <linux/of_platform.h>
  25 #include <linux/percpu.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/pm.h>
  28 #include <linux/ptrace.h>
  29 #include <linux/preempt.h>
  30 #include <linux/reboot.h>
  31 #include <linux/slab.h>
  32 #include <linux/smp.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/uaccess.h>
  35
  36 /*
  37  * The call to use to reach the firmware.
  38  */
  39 static asmlinkage void (*sdei_firmware_call)(unsigned long function_id,
  40                       unsigned long arg0, unsigned long arg1,
  41                       unsigned long arg2, unsigned long arg3,
  42                       unsigned long arg4, struct arm_smccc_res *res);
  43
  44 /* entry point from firmware to arch asm code */
  45 static unsigned long sdei_entry_point;
  46
  47 struct sdei_event {
  48         /* These three are protected by the sdei_list_lock */
  49         struct list_head        list;
  50         bool                    reregister;
  51         bool                    reenable;
  52
  53         u32                     event_num;
  54         u8                      type;
  55         u8                      priority;
  56
  57         /* This pointer is handed to firmware as the event argument. */
  58         union {
  59                 /* Shared events */
  60                 struct sdei_registered_event *registered;
  61
  62                 /* CPU private events */
  63                 struct sdei_registered_event __percpu *private_registered;
  64         };
  65 };
  66
  67 /* Take the mutex for any API call or modification. Take the mutex first. */
  68 static DEFINE_MUTEX(sdei_events_lock);
  69
  70 /* and then hold this when modifying the list */
  71 static DEFINE_SPINLOCK(sdei_list_lock);
  72 static LIST_HEAD(sdei_list);
  73
  74 /* Private events are registered/enabled via IPI passing one of these */
  75 struct sdei_crosscall_args {
  76         struct sdei_event *event;
  77         atomic_t errors;
  78         int first_error;
  79 };
  80
  81 #define CROSSCALL_INIT(arg, event)      (arg.event = event, \
  82                                          arg.first_error = 0, \
  83                                          atomic_set(&arg.errors, 0))
  84
  85 static inline int sdei_do_cross_call(void *fn, struct sdei_event * event)
  86 {
  87         struct sdei_crosscall_args arg;
  88
  89         CROSSCALL_INIT(arg, event);
  90         on_each_cpu(fn, &arg, true);
  91
  92         return arg.first_error;
  93 }
  94
  95 static inline void
  96 sdei_cross_call_return(struct sdei_crosscall_args *arg, int err)
  97 {
  98         if (err && (atomic_inc_return(&arg->errors) == 1))
  99                 arg->first_error = err;
 100 }
 101
 102 static int sdei_to_linux_errno(unsigned long sdei_err)
 103 {
 104         switch (sdei_err) {
 105         case SDEI_NOT_SUPPORTED:
 106                 return -EOPNOTSUPP;
 107         case SDEI_INVALID_PARAMETERS:
 108                 return -EINVAL;
 109         case SDEI_DENIED:
 110                 return -EPERM;
 111         case SDEI_PENDING:
 112                 return -EINPROGRESS;
 113         case SDEI_OUT_OF_RESOURCE:
 114                 return -ENOMEM;
 115         }
 116
 117         /* Not an error value ... */
 118         return sdei_err;
 119 }
 120
 121 /*
 122  * If x0 is any of these values, then the call failed, use sdei_to_linux_errno()
 123  * to translate.
 124  */
 125 static int sdei_is_err(struct arm_smccc_res *res)
 126 {
 127         switch (res->a0) {
 128         case SDEI_NOT_SUPPORTED:
 129         case SDEI_INVALID_PARAMETERS:
 130         case SDEI_DENIED:
 131         case SDEI_PENDING:
 132         case SDEI_OUT_OF_RESOURCE:
 133                 return true;
 134         }
 135
 136         return false;
 137 }
 138
 139 static int invoke_sdei_fn(unsigned long function_id, unsigned long arg0,
 140                           unsigned long arg1, unsigned long arg2,
 141                           unsigned long arg3, unsigned long arg4,
 142                           u64 *result)
 143 {
 144         int err = 0;
 145         struct arm_smccc_res res;
 146
 147         if (sdei_firmware_call) {
 148                 sdei_firmware_call(function_id, arg0, arg1, arg2, arg3, arg4,
 149                                    &res);
 150                 if (sdei_is_err(&res))
 151                         err = sdei_to_linux_errno(res.a0);
 152         } else {
 153                 /*
 154                  * !sdei_firmware_call means we failed to probe or called
 155                  * sdei_mark_interface_broken(). -EIO is not an error returned
 156                  * by sdei_to_linux_errno() and is used to suppress messages
 157                  * from this driver.
 158                  */
 159                 err = -EIO;
 160                 res.a0 = SDEI_NOT_SUPPORTED;
 161         }
 162
 163         if (result)
 164                 *result = res.a0;
 165
 166         return err;
 167 }
 168
 169 static struct sdei_event *sdei_event_find(u32 event_num)
 170 {
 171         struct sdei_event *e, *found = NULL;
 172
 173         lockdep_assert_held(&sdei_events_lock);
 174
 175         spin_lock(&sdei_list_lock);
 176         list_for_each_entry(e, &sdei_list, list) {
 177                 if (e->event_num == event_num) {
 178                         found = e;
 179                         break;
 180                 }
 181         }
 182         spin_unlock(&sdei_list_lock);
 183
 184         return found;
 185 }
 186
 187 int sdei_api_event_context(u32 query, u64 *result)
 188 {
 189         return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_CONTEXT, query, 0, 0, 0, 0,
 190                               result);
 191 }
 192 NOKPROBE_SYMBOL(sdei_api_event_context);
 193
 194 static int sdei_api_event_get_info(u32 event, u32 info, u64 *result)
 195 {
 196         return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_GET_INFO, event, info, 0,
 197                               0, 0, result);
 198 }
 199
 200 static struct sdei_event *sdei_event_create(u32 event_num,
 201                                             sdei_event_callback *cb,
 202                                             void *cb_arg)
 203 {
 204         int err;
 205         u64 result;
 206         struct sdei_event *event;
 207         struct sdei_registered_event *reg;
 208
 209         lockdep_assert_held(&sdei_events_lock);
 210
 211         event = kzalloc(sizeof(*event), GFP_KERNEL);
 212         if (!event)
 213                 return ERR_PTR(-ENOMEM);
 214
 215         INIT_LIST_HEAD(&event->list);
 216         event->event_num = event_num;
 217
 218         err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_PRIORITY,
 219                                       &result);
 220         if (err) {
 221                 kfree(event);
 222                 return ERR_PTR(err);
 223         }
 224         event->priority = result;
 225
 226         err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_TYPE,
 227                                       &result);
 228         if (err) {
 229                 kfree(event);
 230                 return ERR_PTR(err);
 231         }
 232         event->type = result;
 233
 234         if (event->type == SDEI_EVENT_TYPE_SHARED) {
 235                 reg = kzalloc(sizeof(*reg), GFP_KERNEL);
 236                 if (!reg) {
 237                         kfree(event);
 238                         return ERR_PTR(-ENOMEM);
 239                 }
 240
 241                 reg->event_num = event_num;
 242                 reg->priority = event->priority;
 243
 244                 reg->callback = cb;
 245                 reg->callback_arg = cb_arg;
 246                 event->registered = reg;
 247         } else {
 248                 int cpu;
 249                 struct sdei_registered_event __percpu *regs;
 250
 251                 regs = alloc_percpu(struct sdei_registered_event);
 252                 if (!regs) {
 253                         kfree(event);
 254                         return ERR_PTR(-ENOMEM);
 255                 }
 256
 257                 for_each_possible_cpu(cpu) {
 258                         reg = per_cpu_ptr(regs, cpu);
 259
 260                         reg->event_num = event->event_num;
 261                         reg->priority = event->priority;
 262                         reg->callback = cb;
 263                         reg->callback_arg = cb_arg;
 264                 }
 265
 266                 event->private_registered = regs;
 267         }
 268
 269         if (sdei_event_find(event_num)) {
 270                 kfree(event->registered);
 271                 kfree(event);
 272                 event = ERR_PTR(-EBUSY);
 273         } else {
 274                 spin_lock(&sdei_list_lock);
 275                 list_add(&event->list, &sdei_list);
 276                 spin_unlock(&sdei_list_lock);
 277         }
 278
 279         return event;
 280 }
 281
 282 static void sdei_event_destroy(struct sdei_event *event)
 283 {
 284         lockdep_assert_held(&sdei_events_lock);
 285
 286         spin_lock(&sdei_list_lock);
 287         list_del(&event->list);
 288         spin_unlock(&sdei_list_lock);
 289
 290         if (event->type == SDEI_EVENT_TYPE_SHARED)
 291                 kfree(event->registered);
 292         else
 293                 free_percpu(event->private_registered);
 294
 295         kfree(event);
 296 }
 297
 298 static int sdei_api_get_version(u64 *version)
 299 {
 300         return invoke_sdei_fn(SDEI_1_0_FN_SDEI_VERSION, 0, 0, 0, 0, 0, version);
 301 }
 302
 303 int sdei_mask_local_cpu(void)
 304 {
 305         int err;
 306
 307         WARN_ON_ONCE(preemptible());
 308
 309         err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_MASK, 0, 0, 0, 0, 0, NULL);
 310         if (err && err != -EIO) {
 311                 pr_warn_once("failed to mask CPU[%u]: %d\n",
 312                               smp_processor_id(), err);
 313                 return err;
 314         }
 315
 316         return 0;
 317 }
 318
 319 static void _ipi_mask_cpu(void *ignored)
 320 {
 321         sdei_mask_local_cpu();
 322 }
 323
 324 int sdei_unmask_local_cpu(void)
 325 {
 326         int err;
 327
 328         WARN_ON_ONCE(preemptible());
 329
 330         err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_UNMASK, 0, 0, 0, 0, 0, NULL);
 331         if (err && err != -EIO) {
 332                 pr_warn_once("failed to unmask CPU[%u]: %d\n",
 333                              smp_processor_id(), err);
 334                 return err;
 335         }
 336
 337         return 0;
 338 }
 339
 340 static void _ipi_unmask_cpu(void *ignored)
 341 {
 342         sdei_unmask_local_cpu();
 343 }
 344
 345 static void _ipi_private_reset(void *ignored)
 346 {
 347         int err;
 348
 349         err = invoke_sdei_fn(SDEI_1_0_FN_SDEI_PRIVATE_RESET, 0, 0, 0, 0, 0,
 350                              NULL);
 351         if (err && err != -EIO)
 352                 pr_warn_once("failed to reset CPU[%u]: %d\n",
 353                              smp_processor_id(), err);
 354 }
 355
 356 static int sdei_api_shared_reset(void)
 357 {
 358         return invoke_sdei_fn(SDEI_1_0_FN_SDEI_SHARED_RESET, 0, 0, 0, 0, 0,
 359                               NULL);
 360 }
 361
 362 static void sdei_mark_interface_broken(void)
 363 {
 364         pr_err("disabling SDEI firmware interface\n");
 365         on_each_cpu(&_ipi_mask_cpu, NULL, true);
 366         sdei_firmware_call = NULL;
 367 }
 368
 369 static int sdei_platform_reset(void)
 370 {
 371         int err;
 372
 373         on_each_cpu(&_ipi_private_reset, NULL, true);
 374         err = sdei_api_shared_reset();
 375         if (err) {
 376                 pr_err("Failed to reset platform: %d\n", err);
 377                 sdei_mark_interface_broken();
 378         }
 379
 380         return err;
 381 }
 382
 383 static int sdei_api_event_enable(u32 event_num)
 384 {
 385         return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_ENABLE, event_num, 0, 0, 0,
 386                               0, NULL);
 387 }
 388
 389 /* Called directly by the hotplug callbacks */
 390 static void _local_event_enable(void *data)
 391 {
 392         int err;
 393         struct sdei_crosscall_args *arg = data;
 394
 395         WARN_ON_ONCE(preemptible());
 396
 397         err = sdei_api_event_enable(arg->event->event_num);
 398
 399         sdei_cross_call_return(arg, err);
 400 }
 401
 402 int sdei_event_enable(u32 event_num)
 403 {
 404         int err = -EINVAL;
 405         struct sdei_event *event;
 406
 407         mutex_lock(&sdei_events_lock);
 408         event = sdei_event_find(event_num);
 409         if (!event) {
 410                 mutex_unlock(&sdei_events_lock);
 411                 return -ENOENT;
 412         }
 413
 414         spin_lock(&sdei_list_lock);
 415         event->reenable = true;
 416         spin_unlock(&sdei_list_lock);
 417
 418         if (event->type == SDEI_EVENT_TYPE_SHARED)
 419                 err = sdei_api_event_enable(event->event_num);
 420         else
 421                 err = sdei_do_cross_call(_local_event_enable, event);
 422         mutex_unlock(&sdei_events_lock);
 423
 424         return err;
 425 }
 426 EXPORT_SYMBOL(sdei_event_enable);
 427
 428 static int sdei_api_event_disable(u32 event_num)
 429 {
 430         return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_DISABLE, event_num, 0, 0,
 431                               0, 0, NULL);
 432 }
 433
 434 static void _ipi_event_disable(void *data)
 435 {
 436         int err;
 437         struct sdei_crosscall_args *arg = data;
 438
 439         err = sdei_api_event_disable(arg->event->event_num);
 440
 441         sdei_cross_call_return(arg, err);
 442 }
 443
 444 int sdei_event_disable(u32 event_num)
 445 {
 446         int err = -EINVAL;
 447         struct sdei_event *event;
 448
 449         mutex_lock(&sdei_events_lock);
 450         event = sdei_event_find(event_num);
 451         if (!event) {
 452                 mutex_unlock(&sdei_events_lock);
 453                 return -ENOENT;
 454         }
 455
 456         spin_lock(&sdei_list_lock);
 457         event->reenable = false;
 458         spin_unlock(&sdei_list_lock);
 459
 460         if (event->type == SDEI_EVENT_TYPE_SHARED)
 461                 err = sdei_api_event_disable(event->event_num);
 462         else
 463                 err = sdei_do_cross_call(_ipi_event_disable, event);
 464         mutex_unlock(&sdei_events_lock);
 465
 466         return err;
 467 }
 468 EXPORT_SYMBOL(sdei_event_disable);
 469
 470 static int sdei_api_event_unregister(u32 event_num)
 471 {
 472         return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_UNREGISTER, event_num, 0,
 473                               0, 0, 0, NULL);
 474 }
 475
 476 /* Called directly by the hotplug callbacks */
 477 static void _local_event_unregister(void *data)
 478 {
 479         int err;
 480         struct sdei_crosscall_args *arg = data;
 481
 482         WARN_ON_ONCE(preemptible());
 483
 484         err = sdei_api_event_unregister(arg->event->event_num);
 485
 486         sdei_cross_call_return(arg, err);
 487 }
 488
 489 static int _sdei_event_unregister(struct sdei_event *event)
 490 {
 491         lockdep_assert_held(&sdei_events_lock);
 492
 493         spin_lock(&sdei_list_lock);
 494         event->reregister = false;
 495         event->reenable = false;
 496         spin_unlock(&sdei_list_lock);
 497
 498         if (event->type == SDEI_EVENT_TYPE_SHARED)
 499                 return sdei_api_event_unregister(event->event_num);
 500
 501         return sdei_do_cross_call(_local_event_unregister, event);
 502 }
 503
 504 int sdei_event_unregister(u32 event_num)
 505 {
 506         int err;
 507         struct sdei_event *event;
 508
 509         WARN_ON(in_nmi());
 510
 511         mutex_lock(&sdei_events_lock);
 512         event = sdei_event_find(event_num);
 513         do {
 514                 if (!event) {
 515                         pr_warn("Event %u not registered\n", event_num);
 516                         err = -ENOENT;
 517                         break;
 518                 }
 519
 520                 err = _sdei_event_unregister(event);
 521                 if (err)
 522                         break;
 523
 524                 sdei_event_destroy(event);
 525         } while (0);
 526         mutex_unlock(&sdei_events_lock);
 527
 528         return err;
 529 }
 530 EXPORT_SYMBOL(sdei_event_unregister);
 531
 532 /*
 533  * unregister events, but don't destroy them as they are re-registered by
 534  * sdei_reregister_shared().
 535  */
 536 static int sdei_unregister_shared(void)
 537 {
 538         int err = 0;
 539         struct sdei_event *event;
 540
 541         mutex_lock(&sdei_events_lock);
 542         spin_lock(&sdei_list_lock);
 543         list_for_each_entry(event, &sdei_list, list) {
 544                 if (event->type != SDEI_EVENT_TYPE_SHARED)
 545                         continue;
 546
 547                 err = _sdei_event_unregister(event);
 548                 if (err)
 549                         break;
 550         }
 551         spin_unlock(&sdei_list_lock);
 552         mutex_unlock(&sdei_events_lock);
 553
 554         return err;
 555 }
 556
 557 static int sdei_api_event_register(u32 event_num, unsigned long entry_point,
 558                                    void *arg, u64 flags, u64 affinity)
 559 {
 560         return invoke_sdei_fn(SDEI_1_0_FN_SDEI_EVENT_REGISTER, event_num,
 561                               (unsigned long)entry_point, (unsigned long)arg,
 562                               flags, affinity, NULL);
 563 }
 564
 565 /* Called directly by the hotplug callbacks */
 566 static void _local_event_register(void *data)
 567 {
 568         int err;
 569         struct sdei_registered_event *reg;
 570         struct sdei_crosscall_args *arg = data;
 571
 572         WARN_ON(preemptible());
 573
 574         reg = per_cpu_ptr(arg->event->private_registered, smp_processor_id());
 575         err = sdei_api_event_register(arg->event->event_num, sdei_entry_point,
 576                                       reg, 0, 0);
 577
 578         sdei_cross_call_return(arg, err);
 579 }
 580
 581 static int _sdei_event_register(struct sdei_event *event)
 582 {
 583         int err;
 584
 585         lockdep_assert_held(&sdei_events_lock);
 586
 587         spin_lock(&sdei_list_lock);
 588         event->reregister = true;
 589         spin_unlock(&sdei_list_lock);
 590
 591         if (event->type == SDEI_EVENT_TYPE_SHARED)
 592                 return sdei_api_event_register(event->event_num,
 593                                                sdei_entry_point,
 594                                                event->registered,
 595                                                SDEI_EVENT_REGISTER_RM_ANY, 0);
 596
 597
 598         err = sdei_do_cross_call(_local_event_register, event);
 599         if (err) {
 600                 spin_lock(&sdei_list_lock);
 601                 event->reregister = false;
 602                 event->reenable = false;
 603                 spin_unlock(&sdei_list_lock);
 604
 605                 sdei_do_cross_call(_local_event_unregister, event);
 606         }
 607
 608         return err;
 609 }
 610
 611 int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
 612 {
 613         int err;
 614         struct sdei_event *event;
 615
 616         WARN_ON(in_nmi());
 617
 618         mutex_lock(&sdei_events_lock);
 619         do {
 620                 if (sdei_event_find(event_num)) {
 621                         pr_warn("Event %u already registered\n", event_num);
 622                         err = -EBUSY;
 623                         break;
 624                 }
 625
 626                 event = sdei_event_create(event_num, cb, arg);
 627                 if (IS_ERR(event)) {
 628                         err = PTR_ERR(event);
 629                         pr_warn("Failed to create event %u: %d\n", event_num,
 630                                 err);
 631                         break;
 632                 }
 633
 634                 err = _sdei_event_register(event);
 635                 if (err) {
 636                         sdei_event_destroy(event);
 637                         pr_warn("Failed to register event %u: %d\n", event_num,
 638                                 err);
 639                 }
 640         } while (0);
 641         mutex_unlock(&sdei_events_lock);
 642
 643         return err;
 644 }
 645 EXPORT_SYMBOL(sdei_event_register);
 646
 647 static int sdei_reregister_event(struct sdei_event *event)
 648 {
 649         int err;
 650
 651         lockdep_assert_held(&sdei_events_lock);
 652
 653         err = _sdei_event_register(event);
 654         if (err) {
 655                 pr_err("Failed to re-register event %u\n", event->event_num);
 656                 sdei_event_destroy(event);
 657                 return err;
 658         }
 659
 660         if (event->reenable) {
 661                 if (event->type == SDEI_EVENT_TYPE_SHARED)
 662                         err = sdei_api_event_enable(event->event_num);
 663                 else
 664                         err = sdei_do_cross_call(_local_event_enable, event);
 665         }
 666
 667         if (err)
 668                 pr_err("Failed to re-enable event %u\n", event->event_num);
 669
 670         return err;
 671 }
 672
 673 static int sdei_reregister_shared(void)
 674 {
 675         int err = 0;
 676         struct sdei_event *event;
 677
 678         mutex_lock(&sdei_events_lock);
 679         spin_lock(&sdei_list_lock);
 680         list_for_each_entry(event, &sdei_list, list) {
 681                 if (event->type != SDEI_EVENT_TYPE_SHARED)
 682                         continue;
 683
 684                 if (event->reregister) {
 685                         err = sdei_reregister_event(event);
 686                         if (err)
 687                                 break;
 688                 }
 689         }
 690         spin_unlock(&sdei_list_lock);
 691         mutex_unlock(&sdei_events_lock);
 692
 693         return err;
 694 }
 695
 696 static int sdei_cpuhp_down(unsigned int cpu)
 697 {
 698         struct sdei_event *event;
 699         struct sdei_crosscall_args arg;
 700
 701         /* un-register private events */
 702         spin_lock(&sdei_list_lock);
 703         list_for_each_entry(event, &sdei_list, list) {
 704                 if (event->type == SDEI_EVENT_TYPE_SHARED)
 705                         continue;
 706
 707                 CROSSCALL_INIT(arg, event);
 708                 /* call the cross-call function locally... */
 709                 _local_event_unregister(&arg);
 710                 if (arg.first_error)
 711                         pr_err("Failed to unregister event %u: %d\n",
 712                                event->event_num, arg.first_error);
 713         }
 714         spin_unlock(&sdei_list_lock);
 715
 716         return sdei_mask_local_cpu();
 717 }
 718
 719 static int sdei_cpuhp_up(unsigned int cpu)
 720 {
 721         struct sdei_event *event;
 722         struct sdei_crosscall_args arg;
 723
 724         /* re-register/enable private events */
 725         spin_lock(&sdei_list_lock);
 726         list_for_each_entry(event, &sdei_list, list) {
 727                 if (event->type == SDEI_EVENT_TYPE_SHARED)
 728                         continue;
 729
 730                 if (event->reregister) {
 731                         CROSSCALL_INIT(arg, event);
 732                         /* call the cross-call function locally... */
 733                         _local_event_register(&arg);
 734                         if (arg.first_error)
 735                                 pr_err("Failed to re-register event %u: %d\n",
 736                                        event->event_num, arg.first_error);
 737                 }
 738
 739                 if (event->reenable) {
 740                         CROSSCALL_INIT(arg, event);
 741                         _local_event_enable(&arg);
 742                         if (arg.first_error)
 743                                 pr_err("Failed to re-enable event %u: %d\n",
 744                                        event->event_num, arg.first_error);
 745                 }
 746         }
 747         spin_unlock(&sdei_list_lock);
 748
 749         return sdei_unmask_local_cpu();
 750 }
 751
 752 /* When entering idle, mask/unmask events for this cpu */
 753 static int sdei_pm_notifier(struct notifier_block *nb, unsigned long action,
 754                             void *data)
 755 {
 756         int rv;
 757
 758         switch (action) {
 759         case CPU_PM_ENTER:
 760                 rv = sdei_mask_local_cpu();
 761                 break;
 762         case CPU_PM_EXIT:
 763         case CPU_PM_ENTER_FAILED:
 764                 rv = sdei_unmask_local_cpu();
 765                 break;
 766         default:
 767                 return NOTIFY_DONE;
 768         }
 769
 770         if (rv)
 771                 return notifier_from_errno(rv);
 772
 773         return NOTIFY_OK;
 774 }
 775
 776 static struct notifier_block sdei_pm_nb = {
 777         .notifier_call = sdei_pm_notifier,
 778 };
 779
 780 static int sdei_device_suspend(struct device *dev)
 781 {
 782         on_each_cpu(_ipi_mask_cpu, NULL, true);
 783
 784         return 0;
 785 }
 786
 787 static int sdei_device_resume(struct device *dev)
 788 {
 789         on_each_cpu(_ipi_unmask_cpu, NULL, true);
 790
 791         return 0;
 792 }
 793
 794 /*
 795  * We need all events to be reregistered when we resume from hibernate.
 796  *
 797  * The sequence is freeze->thaw. Reboot. freeze->restore. We unregister
 798  * events during freeze, then re-register and re-enable them during thaw
 799  * and restore.
 800  */
 801 static int sdei_device_freeze(struct device *dev)
 802 {
 803         int err;
 804
 805         /* unregister private events */
 806         cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING);
 807
 808         err = sdei_unregister_shared();
 809         if (err)
 810                 return err;
 811
 812         return 0;
 813 }
 814
 815 static int sdei_device_thaw(struct device *dev)
 816 {
 817         int err;
 818
 819         /* re-register shared events */
 820         err = sdei_reregister_shared();
 821         if (err) {
 822                 pr_warn("Failed to re-register shared events...\n");
 823                 sdei_mark_interface_broken();
 824                 return err;
 825         }
 826
 827         err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI",
 828                                 &sdei_cpuhp_up, &sdei_cpuhp_down);
 829         if (err)
 830                 pr_warn("Failed to re-register CPU hotplug notifier...\n");
 831
 832         return err;
 833 }
 834
 835 static int sdei_device_restore(struct device *dev)
 836 {
 837         int err;
 838
 839         err = sdei_platform_reset();
 840         if (err)
 841                 return err;
 842
 843         return sdei_device_thaw(dev);
 844 }
 845
 846 static const struct dev_pm_ops sdei_pm_ops = {
 847         .suspend = sdei_device_suspend,
 848         .resume = sdei_device_resume,
 849         .freeze = sdei_device_freeze,
 850         .thaw = sdei_device_thaw,
 851         .restore = sdei_device_restore,
 852 };
 853
 854 /*
 855  * Mask all CPUs and unregister all events on panic, reboot or kexec.
 856  */
 857 static int sdei_reboot_notifier(struct notifier_block *nb, unsigned long action,
 858                                 void *data)
 859 {
 860         /*
 861          * We are going to reset the interface, after this there is no point
 862          * doing work when we take CPUs offline.
 863          */
 864         cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING);
 865
 866         sdei_platform_reset();
 867
 868         return NOTIFY_OK;
 869 }
 870
 871 static struct notifier_block sdei_reboot_nb = {
 872         .notifier_call = sdei_reboot_notifier,
 873 };
 874
 875 static void sdei_smccc_smc(unsigned long function_id,
 876                            unsigned long arg0, unsigned long arg1,
 877                            unsigned long arg2, unsigned long arg3,
 878                            unsigned long arg4, struct arm_smccc_res *res)
 879 {
 880         arm_smccc_smc(function_id, arg0, arg1, arg2, arg3, arg4, 0, 0, res);
 881 }
 882
 883 static void sdei_smccc_hvc(unsigned long function_id,
 884                            unsigned long arg0, unsigned long arg1,
 885                            unsigned long arg2, unsigned long arg3,
 886                            unsigned long arg4, struct arm_smccc_res *res)
 887 {
 888         arm_smccc_hvc(function_id, arg0, arg1, arg2, arg3, arg4, 0, 0, res);
 889 }
 890
 891 int sdei_register_ghes(struct ghes *ghes, sdei_event_callback *normal_cb,
 892                        sdei_event_callback *critical_cb)
 893 {
 894         int err;
 895         u64 result;
 896         u32 event_num;
 897         sdei_event_callback *cb;
 898
 899         if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES))
 900                 return -EOPNOTSUPP;
 901
 902         event_num = ghes->generic->notify.vector;
 903         if (event_num == 0) {
 904                 /*
 905                  * Event 0 is reserved by the specification for
 906                  * SDEI_EVENT_SIGNAL.
 907                  */
 908                 return -EINVAL;
 909         }
 910
 911         err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_PRIORITY,
 912                                       &result);
 913         if (err)
 914                 return err;
 915
 916         if (result == SDEI_EVENT_PRIORITY_CRITICAL)
 917                 cb = critical_cb;
 918         else
 919                 cb = normal_cb;
 920
 921         err = sdei_event_register(event_num, cb, ghes);
 922         if (!err)
 923                 err = sdei_event_enable(event_num);
 924
 925         return err;
 926 }
 927
 928 int sdei_unregister_ghes(struct ghes *ghes)
 929 {
 930         int i;
 931         int err;
 932         u32 event_num = ghes->generic->notify.vector;
 933
 934         might_sleep();
 935
 936         if (!IS_ENABLED(CONFIG_ACPI_APEI_GHES))
 937                 return -EOPNOTSUPP;
 938
 939         /*
 940          * The event may be running on another CPU. Disable it
 941          * to stop new events, then try to unregister a few times.
 942          */
 943         err = sdei_event_disable(event_num);
 944         if (err)
 945                 return err;
 946
 947         for (i = 0; i < 3; i++) {
 948                 err = sdei_event_unregister(event_num);
 949                 if (err != -EINPROGRESS)
 950                         break;
 951
 952                 schedule();
 953         }
 954
 955         return err;
 956 }
 957
 958 static int sdei_get_conduit(struct platform_device *pdev)
 959 {
 960         const char *method;
 961         struct device_node *np = pdev->dev.of_node;
 962
 963         sdei_firmware_call = NULL;
 964         if (np) {
 965                 if (of_property_read_string(np, "method", &method)) {
 966                         pr_warn("missing \"method\" property\n");
 967                         return CONDUIT_INVALID;
 968                 }
 969
 970                 if (!strcmp("hvc", method)) {
 971                         sdei_firmware_call = &sdei_smccc_hvc;
 972                         return CONDUIT_HVC;
 973                 } else if (!strcmp("smc", method)) {
 974                         sdei_firmware_call = &sdei_smccc_smc;
 975                         return CONDUIT_SMC;
 976                 }
 977
 978                 pr_warn("invalid \"method\" property: %s\n", method);
 979         } else if (IS_ENABLED(CONFIG_ACPI) && !acpi_disabled) {
 980                 if (acpi_psci_use_hvc()) {
 981                         sdei_firmware_call = &sdei_smccc_hvc;
 982                         return CONDUIT_HVC;
 983                 } else {
 984                         sdei_firmware_call = &sdei_smccc_smc;
 985                         return CONDUIT_SMC;
 986                 }
 987         }
 988
 989         return CONDUIT_INVALID;
 990 }
 991
 992 static int sdei_probe(struct platform_device *pdev)
 993 {
 994         int err;
 995         u64 ver = 0;
 996         int conduit;
 997
 998         conduit = sdei_get_conduit(pdev);
 999         if (!sdei_firmware_call)
1000                 return 0;
1001
1002         err = sdei_api_get_version(&ver);
1003         if (err == -EOPNOTSUPP)
1004                 pr_err("advertised but not implemented in platform firmware\n");
1005         if (err) {
1006                 pr_err("Failed to get SDEI version: %d\n", err);
1007                 sdei_mark_interface_broken();
1008                 return err;
1009         }
1010
1011         pr_info("SDEIv%d.%d (0x%x) detected in firmware.\n",
1012                 (int)SDEI_VERSION_MAJOR(ver), (int)SDEI_VERSION_MINOR(ver),
1013                 (int)SDEI_VERSION_VENDOR(ver));
1014
1015         if (SDEI_VERSION_MAJOR(ver) != 1) {
1016                 pr_warn("Conflicting SDEI version detected.\n");
1017                 sdei_mark_interface_broken();
1018                 return -EINVAL;
1019         }
1020
1021         err = sdei_platform_reset();
1022         if (err)
1023                 return err;
1024
1025         sdei_entry_point = sdei_arch_get_entry_point(conduit);
1026         if (!sdei_entry_point) {
1027                 /* Not supported due to hardware or boot configuration */
1028                 sdei_mark_interface_broken();
1029                 return 0;
1030         }
1031
1032         err = cpu_pm_register_notifier(&sdei_pm_nb);
1033         if (err) {
1034                 pr_warn("Failed to register CPU PM notifier...\n");
1035                 goto error;
1036         }
1037
1038         err = register_reboot_notifier(&sdei_reboot_nb);
1039         if (err) {
1040                 pr_warn("Failed to register reboot notifier...\n");
1041                 goto remove_cpupm;
1042         }
1043
1044         err = cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI",
1045                                 &sdei_cpuhp_up, &sdei_cpuhp_down);
1046         if (err) {
1047                 pr_warn("Failed to register CPU hotplug notifier...\n");
1048                 goto remove_reboot;
1049         }
1050
1051         return 0;
1052
1053 remove_reboot:
1054         unregister_reboot_notifier(&sdei_reboot_nb);
1055
1056 remove_cpupm:
1057         cpu_pm_unregister_notifier(&sdei_pm_nb);
1058
1059 error:
1060         sdei_mark_interface_broken();
1061         return err;
1062 }
1063
1064 static const struct of_device_id sdei_of_match[] = {
1065         { .compatible = "arm,sdei-1.0" },
1066         {}
1067 };
1068
1069 static struct platform_driver sdei_driver = {
1070         .driver         = {
1071                 .name                   = "sdei",
1072                 .pm                     = &sdei_pm_ops,
1073                 .of_match_table         = sdei_of_match,
1074         },
1075         .probe          = sdei_probe,
1076 };
1077
1078 static bool __init sdei_present_dt(void)
1079 {
1080         struct device_node *np, *fw_np;
1081
1082         fw_np = of_find_node_by_name(NULL, "firmware");
1083         if (!fw_np)
1084                 return false;
1085
1086         np = of_find_matching_node(fw_np, sdei_of_match);
1087         if (!np)
1088                 return false;
1089         of_node_put(np);
1090
1091         return true;
1092 }
1093
1094 static bool __init sdei_present_acpi(void)
1095 {
1096         acpi_status status;
1097         struct platform_device *pdev;
1098         struct acpi_table_header *sdei_table_header;
1099
1100         if (acpi_disabled)
1101                 return false;
1102
1103         status = acpi_get_table(ACPI_SIG_SDEI, 0, &sdei_table_header);
1104         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
1105                 const char *msg = acpi_format_exception(status);
1106
1107                 pr_info("Failed to get ACPI:SDEI table, %s\n", msg);
1108         }
1109         if (ACPI_FAILURE(status))
1110                 return false;
1111
1112         pdev = platform_device_register_simple(sdei_driver.driver.name, 0, NULL,
1113                                                0);
1114         if (IS_ERR(pdev))
1115                 return false;
1116
1117         return true;
1118 }
1119
1120 static int __init sdei_init(void)
1121 {
1122         if (sdei_present_dt() || sdei_present_acpi())
1123                 platform_driver_register(&sdei_driver);
1124
1125         return 0;
1126 }
1127
1128 /*
1129  * On an ACPI system SDEI needs to be ready before HEST:GHES tries to register
1130  * its events. ACPI is initialised from a subsys_initcall(), GHES is initialised
1131  * by device_initcall(). We want to be called in the middle.
1132  */
1133 subsys_initcall_sync(sdei_init);
1134
1135 int sdei_event_handler(struct pt_regs *regs,
1136                        struct sdei_registered_event *arg)
1137 {
1138         int err;
1139         mm_segment_t orig_addr_limit;
1140         u32 event_num = arg->event_num;
1141
1142         orig_addr_limit = get_fs();
1143         set_fs(USER_DS);
1144
1145         err = arg->callback(event_num, regs, arg->callback_arg);
1146         if (err)
1147                 pr_err_ratelimited("event %u on CPU %u failed with error: %d\n",
1148                                    event_num, smp_processor_id(), err);
1149
1150         set_fs(orig_addr_limit);
1151
1152         return err;
1153 }
1154 NOKPROBE_SYMBOL(sdei_event_handler);