drivers/acpi/apei/ghes.c

   1 /*
   2  * APEI Generic Hardware Error Source support
   3  *
   4  * Generic Hardware Error Source provides a way to report platform
   5  * hardware errors (such as that from chipset). It works in so called
   6  * "Firmware First" mode, that is, hardware errors are reported to
   7  * firmware firstly, then reported to Linux by firmware. This way,
   8  * some non-standard hardware error registers or non-standard hardware
   9  * link can be checked by firmware to produce more hardware error
  10  * information for Linux.
  11  *
  12  * For more information about Generic Hardware Error Source, please
  13  * refer to ACPI Specification version 4.0, section 17.3.2.6
  14  *
  15  * Copyright 2010 Intel Corp.
  16  *   Author: Huang Ying <ying.huang@intel.com>
  17  *
  18  * This program is free software; you can redistribute it and/or
  19  * modify it under the terms of the GNU General Public License version
  20  * 2 as published by the Free Software Foundation;
  21  *
  22  * This program is distributed in the hope that it will be useful,
  23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  * GNU General Public License for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License
  28  * along with this program; if not, write to the Free Software
  29  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  30  */
  31
  32 #include <linux/kernel.h>
  33 #include <linux/module.h>
  34 #include <linux/init.h>
  35 #include <linux/acpi.h>
  36 #include <linux/io.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/timer.h>
  39 #include <linux/cper.h>
  40 #include <linux/kdebug.h>
  41 #include <linux/platform_device.h>
  42 #include <linux/mutex.h>
  43 #include <linux/ratelimit.h>
  44 #include <linux/vmalloc.h>
  45 #include <acpi/apei.h>
  46 #include <acpi/atomicio.h>
  47 #include <acpi/hed.h>
  48 #include <asm/mce.h>
  49 #include <asm/tlbflush.h>
  50
  51 #include "apei-internal.h"
  52
  53 #define GHES_PFX        "GHES: "
  54
  55 #define GHES_ESTATUS_MAX_SIZE           65536
  56
  57 /*
  58  * One struct ghes is created for each generic hardware error source.
  59  * It provides the context for APEI hardware error timer/IRQ/SCI/NMI
  60  * handler.
  61  *
  62  * estatus: memory buffer for error status block, allocated during
  63  * HEST parsing.
  64  */
  65 #define GHES_TO_CLEAR           0x0001
  66 #define GHES_EXITING            0x0002
  67
  68 struct ghes {
  69         struct acpi_hest_generic *generic;
  70         struct acpi_hest_generic_status *estatus;
  71         u64 buffer_paddr;
  72         unsigned long flags;
  73         union {
  74                 struct list_head list;
  75                 struct timer_list timer;
  76                 unsigned int irq;
  77         };
  78 };
  79
  80 static int ghes_panic_timeout   __read_mostly = 30;
  81
  82 /*
  83  * All error sources notified with SCI shares one notifier function,
  84  * so they need to be linked and checked one by one.  This is applied
  85  * to NMI too.
  86  *
  87  * RCU is used for these lists, so ghes_list_mutex is only used for
  88  * list changing, not for traversing.
  89  */
  90 static LIST_HEAD(ghes_sci);
  91 static LIST_HEAD(ghes_nmi);
  92 static DEFINE_MUTEX(ghes_list_mutex);
  93
  94 /*
  95  * NMI may be triggered on any CPU, so ghes_nmi_lock is used for
  96  * mutual exclusion.
  97  */
  98 static DEFINE_RAW_SPINLOCK(ghes_nmi_lock);
  99
 100 /*
 101  * Because the memory area used to transfer hardware error information
 102  * from BIOS to Linux can be determined only in NMI, IRQ or timer
 103  * handler, but general ioremap can not be used in atomic context, so
 104  * a special version of atomic ioremap is implemented for that.
 105  */
 106
 107 /*
 108  * Two virtual pages are used, one for NMI context, the other for
 109  * IRQ/PROCESS context
 110  */
 111 #define GHES_IOREMAP_PAGES              2
 112 #define GHES_IOREMAP_NMI_PAGE(base)     (base)
 113 #define GHES_IOREMAP_IRQ_PAGE(base)     ((base) + PAGE_SIZE)
 114
 115 /* virtual memory area for atomic ioremap */
 116 static struct vm_struct *ghes_ioremap_area;
 117 /*
 118  * These 2 spinlock is used to prevent atomic ioremap virtual memory
 119  * area from being mapped simultaneously.
 120  */
 121 static DEFINE_RAW_SPINLOCK(ghes_ioremap_lock_nmi);
 122 static DEFINE_SPINLOCK(ghes_ioremap_lock_irq);
 123
 124 static int ghes_ioremap_init(void)
 125 {
 126         ghes_ioremap_area = __get_vm_area(PAGE_SIZE * GHES_IOREMAP_PAGES,
 127                 VM_IOREMAP, VMALLOC_START, VMALLOC_END);
 128         if (!ghes_ioremap_area) {
 129                 pr_err(GHES_PFX "Failed to allocate virtual memory area for atomic ioremap.\n");
 130                 return -ENOMEM;
 131         }
 132
 133         return 0;
 134 }
 135
 136 static void ghes_ioremap_exit(void)
 137 {
 138         free_vm_area(ghes_ioremap_area);
 139 }
 140
 141 static void __iomem *ghes_ioremap_pfn_nmi(u64 pfn)
 142 {
 143         unsigned long vaddr;
 144
 145         vaddr = (unsigned long)GHES_IOREMAP_NMI_PAGE(ghes_ioremap_area->addr);
 146         ioremap_page_range(vaddr, vaddr + PAGE_SIZE,
 147                            pfn << PAGE_SHIFT, PAGE_KERNEL);
 148
 149         return (void __iomem *)vaddr;
 150 }
 151
 152 static void __iomem *ghes_ioremap_pfn_irq(u64 pfn)
 153 {
 154         unsigned long vaddr;
 155
 156         vaddr = (unsigned long)GHES_IOREMAP_IRQ_PAGE(ghes_ioremap_area->addr);
 157         ioremap_page_range(vaddr, vaddr + PAGE_SIZE,
 158                            pfn << PAGE_SHIFT, PAGE_KERNEL);
 159
 160         return (void __iomem *)vaddr;
 161 }
 162
 163 static void ghes_iounmap_nmi(void __iomem *vaddr_ptr)
 164 {
 165         unsigned long vaddr = (unsigned long __force)vaddr_ptr;
 166         void *base = ghes_ioremap_area->addr;
 167
 168         BUG_ON(vaddr != (unsigned long)GHES_IOREMAP_NMI_PAGE(base));
 169         unmap_kernel_range_noflush(vaddr, PAGE_SIZE);
 170         __flush_tlb_one(vaddr);
 171 }
 172
 173 static void ghes_iounmap_irq(void __iomem *vaddr_ptr)
 174 {
 175         unsigned long vaddr = (unsigned long __force)vaddr_ptr;
 176         void *base = ghes_ioremap_area->addr;
 177
 178         BUG_ON(vaddr != (unsigned long)GHES_IOREMAP_IRQ_PAGE(base));
 179         unmap_kernel_range_noflush(vaddr, PAGE_SIZE);
 180         __flush_tlb_one(vaddr);
 181 }
 182
 183 static struct ghes *ghes_new(struct acpi_hest_generic *generic)
 184 {
 185         struct ghes *ghes;
 186         unsigned int error_block_length;
 187         int rc;
 188
 189         ghes = kzalloc(sizeof(*ghes), GFP_KERNEL);
 190         if (!ghes)
 191                 return ERR_PTR(-ENOMEM);
 192         ghes->generic = generic;
 193         rc = acpi_pre_map_gar(&generic->error_status_address);
 194         if (rc)
 195                 goto err_free;
 196         error_block_length = generic->error_block_length;
 197         if (error_block_length > GHES_ESTATUS_MAX_SIZE) {
 198                 pr_warning(FW_WARN GHES_PFX
 199                            "Error status block length is too long: %u for "
 200                            "generic hardware error source: %d.\n",
 201                            error_block_length, generic->header.source_id);
 202                 error_block_length = GHES_ESTATUS_MAX_SIZE;
 203         }
 204         ghes->estatus = kmalloc(error_block_length, GFP_KERNEL);
 205         if (!ghes->estatus) {
 206                 rc = -ENOMEM;
 207                 goto err_unmap;
 208         }
 209
 210         return ghes;
 211
 212 err_unmap:
 213         acpi_post_unmap_gar(&generic->error_status_address);
 214 err_free:
 215         kfree(ghes);
 216         return ERR_PTR(rc);
 217 }
 218
 219 static void ghes_fini(struct ghes *ghes)
 220 {
 221         kfree(ghes->estatus);
 222         acpi_post_unmap_gar(&ghes->generic->error_status_address);
 223 }
 224
 225 enum {
 226         GHES_SEV_NO = 0x0,
 227         GHES_SEV_CORRECTED = 0x1,
 228         GHES_SEV_RECOVERABLE = 0x2,
 229         GHES_SEV_PANIC = 0x3,
 230 };
 231
 232 static inline int ghes_severity(int severity)
 233 {
 234         switch (severity) {
 235         case CPER_SEV_INFORMATIONAL:
 236                 return GHES_SEV_NO;
 237         case CPER_SEV_CORRECTED:
 238                 return GHES_SEV_CORRECTED;
 239         case CPER_SEV_RECOVERABLE:
 240                 return GHES_SEV_RECOVERABLE;
 241         case CPER_SEV_FATAL:
 242                 return GHES_SEV_PANIC;
 243         default:
 244                 /* Unknown, go panic */
 245                 return GHES_SEV_PANIC;
 246         }
 247 }
 248
 249 static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
 250                                   int from_phys)
 251 {
 252         void __iomem *vaddr;
 253         unsigned long flags = 0;
 254         int in_nmi = in_nmi();
 255         u64 offset;
 256         u32 trunk;
 257
 258         while (len > 0) {
 259                 offset = paddr - (paddr & PAGE_MASK);
 260                 if (in_nmi) {
 261                         raw_spin_lock(&ghes_ioremap_lock_nmi);
 262                         vaddr = ghes_ioremap_pfn_nmi(paddr >> PAGE_SHIFT);
 263                 } else {
 264                         spin_lock_irqsave(&ghes_ioremap_lock_irq, flags);
 265                         vaddr = ghes_ioremap_pfn_irq(paddr >> PAGE_SHIFT);
 266                 }
 267                 trunk = PAGE_SIZE - offset;
 268                 trunk = min(trunk, len);
 269                 if (from_phys)
 270                         memcpy_fromio(buffer, vaddr + offset, trunk);
 271                 else
 272                         memcpy_toio(vaddr + offset, buffer, trunk);
 273                 len -= trunk;
 274                 paddr += trunk;
 275                 buffer += trunk;
 276                 if (in_nmi) {
 277                         ghes_iounmap_nmi(vaddr);
 278                         raw_spin_unlock(&ghes_ioremap_lock_nmi);
 279                 } else {
 280                         ghes_iounmap_irq(vaddr);
 281                         spin_unlock_irqrestore(&ghes_ioremap_lock_irq, flags);
 282                 }
 283         }
 284 }
 285
 286 static int ghes_read_estatus(struct ghes *ghes, int silent)
 287 {
 288         struct acpi_hest_generic *g = ghes->generic;
 289         u64 buf_paddr;
 290         u32 len;
 291         int rc;
 292
 293         rc = acpi_atomic_read(&buf_paddr, &g->error_status_address);
 294         if (rc) {
 295                 if (!silent && printk_ratelimit())
 296                         pr_warning(FW_WARN GHES_PFX
 297 "Failed to read error status block address for hardware error source: %d.\n",
 298                                    g->header.source_id);
 299                 return -EIO;
 300         }
 301         if (!buf_paddr)
 302                 return -ENOENT;
 303
 304         ghes_copy_tofrom_phys(ghes->estatus, buf_paddr,
 305                               sizeof(*ghes->estatus), 1);
 306         if (!ghes->estatus->block_status)
 307                 return -ENOENT;
 308
 309         ghes->buffer_paddr = buf_paddr;
 310         ghes->flags |= GHES_TO_CLEAR;
 311
 312         rc = -EIO;
 313         len = apei_estatus_len(ghes->estatus);
 314         if (len < sizeof(*ghes->estatus))
 315                 goto err_read_block;
 316         if (len > ghes->generic->error_block_length)
 317                 goto err_read_block;
 318         if (apei_estatus_check_header(ghes->estatus))
 319                 goto err_read_block;
 320         ghes_copy_tofrom_phys(ghes->estatus + 1,
 321                               buf_paddr + sizeof(*ghes->estatus),
 322                               len - sizeof(*ghes->estatus), 1);
 323         if (apei_estatus_check(ghes->estatus))
 324                 goto err_read_block;
 325         rc = 0;
 326
 327 err_read_block:
 328         if (rc && !silent && printk_ratelimit())
 329                 pr_warning(FW_WARN GHES_PFX
 330                            "Failed to read error status block!\n");
 331         return rc;
 332 }
 333
 334 static void ghes_clear_estatus(struct ghes *ghes)
 335 {
 336         ghes->estatus->block_status = 0;
 337         if (!(ghes->flags & GHES_TO_CLEAR))
 338                 return;
 339         ghes_copy_tofrom_phys(ghes->estatus, ghes->buffer_paddr,
 340                               sizeof(ghes->estatus->block_status), 0);
 341         ghes->flags &= ~GHES_TO_CLEAR;
 342 }
 343
 344 static void ghes_do_proc(struct ghes *ghes)
 345 {
 346         int sev, processed = 0;
 347         struct acpi_hest_generic_data *gdata;
 348
 349         sev = ghes_severity(ghes->estatus->error_severity);
 350         apei_estatus_for_each_section(ghes->estatus, gdata) {
 351 #ifdef CONFIG_X86_MCE
 352                 if (!uuid_le_cmp(*(uuid_le *)gdata->section_type,
 353                                  CPER_SEC_PLATFORM_MEM)) {
 354                         apei_mce_report_mem_error(
 355                                 sev == GHES_SEV_CORRECTED,
 356                                 (struct cper_sec_mem_err *)(gdata+1));
 357                         processed = 1;
 358                 }
 359 #endif
 360         }
 361 }
 362
 363 static void ghes_print_estatus(const char *pfx, struct ghes *ghes)
 364 {
 365         /* Not more than 2 messages every 5 seconds */
 366         static DEFINE_RATELIMIT_STATE(ratelimit, 5*HZ, 2);
 367
 368         if (pfx == NULL) {
 369                 if (ghes_severity(ghes->estatus->error_severity) <=
 370                     GHES_SEV_CORRECTED)
 371                         pfx = KERN_WARNING HW_ERR;
 372                 else
 373                         pfx = KERN_ERR HW_ERR;
 374         }
 375         if (__ratelimit(&ratelimit)) {
 376                 printk(
 377         "%s""Hardware error from APEI Generic Hardware Error Source: %d\n",
 378         pfx, ghes->generic->header.source_id);
 379                 apei_estatus_print(pfx, ghes->estatus);
 380         }
 381 }
 382
 383 static int ghes_proc(struct ghes *ghes)
 384 {
 385         int rc;
 386
 387         rc = ghes_read_estatus(ghes, 0);
 388         if (rc)
 389                 goto out;
 390         ghes_print_estatus(NULL, ghes);
 391         ghes_do_proc(ghes);
 392
 393 out:
 394         ghes_clear_estatus(ghes);
 395         return 0;
 396 }
 397
 398 static void ghes_add_timer(struct ghes *ghes)
 399 {
 400         struct acpi_hest_generic *g = ghes->generic;
 401         unsigned long expire;
 402
 403         if (!g->notify.poll_interval) {
 404                 pr_warning(FW_WARN GHES_PFX "Poll interval is 0 for generic hardware error source: %d, disabled.\n",
 405                            g->header.source_id);
 406                 return;
 407         }
 408         expire = jiffies + msecs_to_jiffies(g->notify.poll_interval);
 409         ghes->timer.expires = round_jiffies_relative(expire);
 410         add_timer(&ghes->timer);
 411 }
 412
 413 static void ghes_poll_func(unsigned long data)
 414 {
 415         struct ghes *ghes = (void *)data;
 416
 417         ghes_proc(ghes);
 418         if (!(ghes->flags & GHES_EXITING))
 419                 ghes_add_timer(ghes);
 420 }
 421
 422 static irqreturn_t ghes_irq_func(int irq, void *data)
 423 {
 424         struct ghes *ghes = data;
 425         int rc;
 426
 427         rc = ghes_proc(ghes);
 428         if (rc)
 429                 return IRQ_NONE;
 430
 431         return IRQ_HANDLED;
 432 }
 433
 434 static int ghes_notify_sci(struct notifier_block *this,
 435                                   unsigned long event, void *data)
 436 {
 437         struct ghes *ghes;
 438         int ret = NOTIFY_DONE;
 439
 440         rcu_read_lock();
 441         list_for_each_entry_rcu(ghes, &ghes_sci, list) {
 442                 if (!ghes_proc(ghes))
 443                         ret = NOTIFY_OK;
 444         }
 445         rcu_read_unlock();
 446
 447         return ret;
 448 }
 449
 450 static int ghes_notify_nmi(struct notifier_block *this,
 451                                   unsigned long cmd, void *data)
 452 {
 453         struct ghes *ghes, *ghes_global = NULL;
 454         int sev, sev_global = -1;
 455         int ret = NOTIFY_DONE;
 456
 457         if (cmd != DIE_NMI)
 458                 return ret;
 459
 460         raw_spin_lock(&ghes_nmi_lock);
 461         list_for_each_entry_rcu(ghes, &ghes_nmi, list) {
 462                 if (ghes_read_estatus(ghes, 1)) {
 463                         ghes_clear_estatus(ghes);
 464                         continue;
 465                 }
 466                 sev = ghes_severity(ghes->estatus->error_severity);
 467                 if (sev > sev_global) {
 468                         sev_global = sev;
 469                         ghes_global = ghes;
 470                 }
 471                 ret = NOTIFY_STOP;
 472         }
 473
 474         if (ret == NOTIFY_DONE)
 475                 goto out;
 476
 477         if (sev_global >= GHES_SEV_PANIC) {
 478                 oops_begin();
 479                 ghes_print_estatus(KERN_EMERG HW_ERR, ghes_global);
 480                 /* reboot to log the error! */
 481                 if (panic_timeout == 0)
 482                         panic_timeout = ghes_panic_timeout;
 483                 panic("Fatal hardware error!");
 484         }
 485
 486         list_for_each_entry_rcu(ghes, &ghes_nmi, list) {
 487                 if (!(ghes->flags & GHES_TO_CLEAR))
 488                         continue;
 489                 /* Do not print estatus because printk is not NMI safe */
 490                 ghes_do_proc(ghes);
 491                 ghes_clear_estatus(ghes);
 492         }
 493
 494 out:
 495         raw_spin_unlock(&ghes_nmi_lock);
 496         return ret;
 497 }
 498
 499 static struct notifier_block ghes_notifier_sci = {
 500         .notifier_call = ghes_notify_sci,
 501 };
 502
 503 static struct notifier_block ghes_notifier_nmi = {
 504         .notifier_call = ghes_notify_nmi,
 505 };
 506
 507 static int __devinit ghes_probe(struct platform_device *ghes_dev)
 508 {
 509         struct acpi_hest_generic *generic;
 510         struct ghes *ghes = NULL;
 511         int rc = -EINVAL;
 512
 513         generic = *(struct acpi_hest_generic **)ghes_dev->dev.platform_data;
 514         if (!generic->enabled)
 515                 return -ENODEV;
 516
 517         switch (generic->notify.type) {
 518         case ACPI_HEST_NOTIFY_POLLED:
 519         case ACPI_HEST_NOTIFY_EXTERNAL:
 520         case ACPI_HEST_NOTIFY_SCI:
 521         case ACPI_HEST_NOTIFY_NMI:
 522                 break;
 523         case ACPI_HEST_NOTIFY_LOCAL:
 524                 pr_warning(GHES_PFX "Generic hardware error source: %d notified via local interrupt is not supported!\n",
 525                            generic->header.source_id);
 526                 goto err;
 527         default:
 528                 pr_warning(FW_WARN GHES_PFX "Unknown notification type: %u for generic hardware error source: %d\n",
 529                            generic->notify.type, generic->header.source_id);
 530                 goto err;
 531         }
 532
 533         rc = -EIO;
 534         if (generic->error_block_length <
 535             sizeof(struct acpi_hest_generic_status)) {
 536                 pr_warning(FW_BUG GHES_PFX "Invalid error block length: %u for generic hardware error source: %d\n",
 537                            generic->error_block_length,
 538                            generic->header.source_id);
 539                 goto err;
 540         }
 541         ghes = ghes_new(generic);
 542         if (IS_ERR(ghes)) {
 543                 rc = PTR_ERR(ghes);
 544                 ghes = NULL;
 545                 goto err;
 546         }
 547         switch (generic->notify.type) {
 548         case ACPI_HEST_NOTIFY_POLLED:
 549                 ghes->timer.function = ghes_poll_func;
 550                 ghes->timer.data = (unsigned long)ghes;
 551                 init_timer_deferrable(&ghes->timer);
 552                 ghes_add_timer(ghes);
 553                 break;
 554         case ACPI_HEST_NOTIFY_EXTERNAL:
 555                 /* External interrupt vector is GSI */
 556                 if (acpi_gsi_to_irq(generic->notify.vector, &ghes->irq)) {
 557                         pr_err(GHES_PFX "Failed to map GSI to IRQ for generic hardware error source: %d\n",
 558                                generic->header.source_id);
 559                         goto err;
 560                 }
 561                 if (request_irq(ghes->irq, ghes_irq_func,
 562                                 0, "GHES IRQ", ghes)) {
 563                         pr_err(GHES_PFX "Failed to register IRQ for generic hardware error source: %d\n",
 564                                generic->header.source_id);
 565                         goto err;
 566                 }
 567                 break;
 568         case ACPI_HEST_NOTIFY_SCI:
 569                 mutex_lock(&ghes_list_mutex);
 570                 if (list_empty(&ghes_sci))
 571                         register_acpi_hed_notifier(&ghes_notifier_sci);
 572                 list_add_rcu(&ghes->list, &ghes_sci);
 573                 mutex_unlock(&ghes_list_mutex);
 574                 break;
 575         case ACPI_HEST_NOTIFY_NMI:
 576                 mutex_lock(&ghes_list_mutex);
 577                 if (list_empty(&ghes_nmi))
 578                         register_die_notifier(&ghes_notifier_nmi);
 579                 list_add_rcu(&ghes->list, &ghes_nmi);
 580                 mutex_unlock(&ghes_list_mutex);
 581                 break;
 582         default:
 583                 BUG();
 584         }
 585         platform_set_drvdata(ghes_dev, ghes);
 586
 587         return 0;
 588 err:
 589         if (ghes) {
 590                 ghes_fini(ghes);
 591                 kfree(ghes);
 592         }
 593         return rc;
 594 }
 595
 596 static int __devexit ghes_remove(struct platform_device *ghes_dev)
 597 {
 598         struct ghes *ghes;
 599         struct acpi_hest_generic *generic;
 600
 601         ghes = platform_get_drvdata(ghes_dev);
 602         generic = ghes->generic;
 603
 604         ghes->flags |= GHES_EXITING;
 605         switch (generic->notify.type) {
 606         case ACPI_HEST_NOTIFY_POLLED:
 607                 del_timer_sync(&ghes->timer);
 608                 break;
 609         case ACPI_HEST_NOTIFY_EXTERNAL:
 610                 free_irq(ghes->irq, ghes);
 611                 break;
 612         case ACPI_HEST_NOTIFY_SCI:
 613                 mutex_lock(&ghes_list_mutex);
 614                 list_del_rcu(&ghes->list);
 615                 if (list_empty(&ghes_sci))
 616                         unregister_acpi_hed_notifier(&ghes_notifier_sci);
 617                 mutex_unlock(&ghes_list_mutex);
 618                 break;
 619         case ACPI_HEST_NOTIFY_NMI:
 620                 mutex_lock(&ghes_list_mutex);
 621                 list_del_rcu(&ghes->list);
 622                 if (list_empty(&ghes_nmi))
 623                         unregister_die_notifier(&ghes_notifier_nmi);
 624                 mutex_unlock(&ghes_list_mutex);
 625                 /*
 626                  * To synchronize with NMI handler, ghes can only be
 627                  * freed after NMI handler finishes.
 628                  */
 629                 synchronize_rcu();
 630                 break;
 631         default:
 632                 BUG();
 633                 break;
 634         }
 635
 636         ghes_fini(ghes);
 637         kfree(ghes);
 638
 639         platform_set_drvdata(ghes_dev, NULL);
 640
 641         return 0;
 642 }
 643
 644 static struct platform_driver ghes_platform_driver = {
 645         .driver         = {
 646                 .name   = "GHES",
 647                 .owner  = THIS_MODULE,
 648         },
 649         .probe          = ghes_probe,
 650         .remove         = ghes_remove,
 651 };
 652
 653 static int __init ghes_init(void)
 654 {
 655         int rc;
 656
 657         if (acpi_disabled)
 658                 return -ENODEV;
 659
 660         if (hest_disable) {
 661                 pr_info(GHES_PFX "HEST is not enabled!\n");
 662                 return -EINVAL;
 663         }
 664
 665         rc = ghes_ioremap_init();
 666         if (rc)
 667                 goto err;
 668
 669         rc = platform_driver_register(&ghes_platform_driver);
 670         if (rc)
 671                 goto err_ioremap_exit;
 672
 673         return 0;
 674 err_ioremap_exit:
 675         ghes_ioremap_exit();
 676 err:
 677         return rc;
 678 }
 679
 680 static void __exit ghes_exit(void)
 681 {
 682         platform_driver_unregister(&ghes_platform_driver);
 683         ghes_ioremap_exit();
 684 }
 685
 686 module_init(ghes_init);
 687 module_exit(ghes_exit);
 688
 689 MODULE_AUTHOR("Huang Ying");
 690 MODULE_DESCRIPTION("APEI Generic Hardware Error Source support");
 691 MODULE_LICENSE("GPL");
 692 MODULE_ALIAS("platform:GHES");