1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * apei-base.c - ACPI Platform Error Interface (APEI) supporting 4 * infrastructure 5 * 6 * APEI allows to report errors (for example from the chipset) to 7 * the operating system. This improves NMI handling especially. In 8 * addition it supports error serialization and error injection. 9 * 10 * For more information about APEI, please refer to ACPI Specification 11 * version 4.0, chapter 17. 12 * 13 * This file has Common functions used by more than one APEI table, 14 * including framework of interpreter for ERST and EINJ; resource 15 * management for APEI registers. 16 * 17 * Copyright (C) 2009, Intel Corp. 18 * Author: Huang Ying <ying.huang@intel.com> 19 */ 20 21#include <linux/kernel.h> 22#include <linux/module.h> 23#include <linux/init.h> 24#include <linux/acpi.h> 25#include <linux/slab.h> 26#include <linux/io.h> 27#include <linux/kref.h> 28#include <linux/interrupt.h> 29#include <linux/debugfs.h> 30#include <acpi/apei.h> 31#include <asm/unaligned.h> 32 33#include "apei-internal.h" 34 35#define APEI_PFX "APEI: " 36 37/* 38 * APEI ERST (Error Record Serialization Table) and EINJ (Error 39 * INJection) interpreter framework. 40 */ 41 42#define APEI_EXEC_PRESERVE_REGISTER 0x1 43 44void apei_exec_ctx_init(struct apei_exec_context *ctx, 45 struct apei_exec_ins_type *ins_table, 46 u32 instructions, 47 struct acpi_whea_header *action_table, 48 u32 entries) 49{ 50 ctx->ins_table = ins_table; 51 ctx->instructions = instructions; 52 ctx->action_table = action_table; 53 ctx->entries = entries; 54} 55EXPORT_SYMBOL_GPL(apei_exec_ctx_init); 56 57int __apei_exec_read_register(struct acpi_whea_header *entry, u64 *val) 58{ 59 int rc; 60 61 rc = apei_read(val, &entry->register_region); 62 if (rc) 63 return rc; 64 *val >>= entry->register_region.bit_offset; 65 *val &= entry->mask; 66 67 return 0; 68} 69 70int apei_exec_read_register(struct apei_exec_context *ctx, 71 struct acpi_whea_header *entry) 72{ 73 int rc; 74 u64 val = 0; 75 76 rc = __apei_exec_read_register(entry, &val); 77 if (rc) 78 return rc; 79 ctx->value = val; 80 81 return 0; 82} 83EXPORT_SYMBOL_GPL(apei_exec_read_register); 84 85int apei_exec_read_register_value(struct apei_exec_context *ctx, 86 struct acpi_whea_header *entry) 87{ 88 int rc; 89 90 rc = apei_exec_read_register(ctx, entry); 91 if (rc) 92 return rc; 93 ctx->value = (ctx->value == entry->value); 94 95 return 0; 96} 97EXPORT_SYMBOL_GPL(apei_exec_read_register_value); 98 99int __apei_exec_write_register(struct acpi_whea_header *entry, u64 val) 100{ 101 int rc; 102 103 val &= entry->mask; 104 val <<= entry->register_region.bit_offset; 105 if (entry->flags & APEI_EXEC_PRESERVE_REGISTER) { 106 u64 valr = 0; 107 rc = apei_read(&valr, &entry->register_region); 108 if (rc) 109 return rc; 110 valr &= ~(entry->mask << entry->register_region.bit_offset); 111 val |= valr; 112 } 113 rc = apei_write(val, &entry->register_region); 114 115 return rc; 116} 117 118int apei_exec_write_register(struct apei_exec_context *ctx, 119 struct acpi_whea_header *entry) 120{ 121 return __apei_exec_write_register(entry, ctx->value); 122} 123EXPORT_SYMBOL_GPL(apei_exec_write_register); 124 125int apei_exec_write_register_value(struct apei_exec_context *ctx, 126 struct acpi_whea_header *entry) 127{ 128 ctx->value = entry->value; 129 130 return apei_exec_write_register(ctx, entry); 131} 132EXPORT_SYMBOL_GPL(apei_exec_write_register_value); 133 134int apei_exec_noop(struct apei_exec_context *ctx, 135 struct acpi_whea_header *entry) 136{ 137 return 0; 138} 139EXPORT_SYMBOL_GPL(apei_exec_noop); 140 141/* 142 * Interpret the specified action. Go through whole action table, 143 * execute all instructions belong to the action. 144 */ 145int __apei_exec_run(struct apei_exec_context *ctx, u8 action, 146 bool optional) 147{ 148 int rc = -ENOENT; 149 u32 i, ip; 150 struct acpi_whea_header *entry; 151 apei_exec_ins_func_t run; 152 153 ctx->ip = 0; 154 155 /* 156 * "ip" is the instruction pointer of current instruction, 157 * "ctx->ip" specifies the next instruction to executed, 158 * instruction "run" function may change the "ctx->ip" to 159 * implement "goto" semantics. 160 */ 161rewind: 162 ip = 0; 163 for (i = 0; i < ctx->entries; i++) { 164 entry = &ctx->action_table[i]; 165 if (entry->action != action) 166 continue; 167 if (ip == ctx->ip) { 168 if (entry->instruction >= ctx->instructions || 169 !ctx->ins_table[entry->instruction].run) { 170 pr_warn(FW_WARN APEI_PFX 171 "Invalid action table, unknown instruction type: %d\n", 172 entry->instruction); 173 return -EINVAL; 174 } 175 run = ctx->ins_table[entry->instruction].run; 176 rc = run(ctx, entry); 177 if (rc < 0) 178 return rc; 179 else if (rc != APEI_EXEC_SET_IP) 180 ctx->ip++; 181 } 182 ip++; 183 if (ctx->ip < ip) 184 goto rewind; 185 } 186 187 return !optional && rc < 0 ? rc : 0; 188} 189EXPORT_SYMBOL_GPL(__apei_exec_run); 190 191typedef int (*apei_exec_entry_func_t)(struct apei_exec_context *ctx, 192 struct acpi_whea_header *entry, 193 void *data); 194 195static int apei_exec_for_each_entry(struct apei_exec_context *ctx, 196 apei_exec_entry_func_t func, 197 void *data, 198 int *end) 199{ 200 u8 ins; 201 int i, rc; 202 struct acpi_whea_header *entry; 203 struct apei_exec_ins_type *ins_table = ctx->ins_table; 204 205 for (i = 0; i < ctx->entries; i++) { 206 entry = ctx->action_table + i; 207 ins = entry->instruction; 208 if (end) 209 *end = i; 210 if (ins >= ctx->instructions || !ins_table[ins].run) { 211 pr_warn(FW_WARN APEI_PFX 212 "Invalid action table, unknown instruction type: %d\n", 213 ins); 214 return -EINVAL; 215 } 216 rc = func(ctx, entry, data); 217 if (rc) 218 return rc; 219 } 220 221 return 0; 222} 223 224static int pre_map_gar_callback(struct apei_exec_context *ctx, 225 struct acpi_whea_header *entry, 226 void *data) 227{ 228 u8 ins = entry->instruction; 229 230 if (ctx->ins_table[ins].flags & APEI_EXEC_INS_ACCESS_REGISTER) 231 return apei_map_generic_address(&entry->register_region); 232 233 return 0; 234} 235 236/* 237 * Pre-map all GARs in action table to make it possible to access them 238 * in NMI handler. 239 */ 240int apei_exec_pre_map_gars(struct apei_exec_context *ctx) 241{ 242 int rc, end; 243 244 rc = apei_exec_for_each_entry(ctx, pre_map_gar_callback, 245 NULL, &end); 246 if (rc) { 247 struct apei_exec_context ctx_unmap; 248 memcpy(&ctx_unmap, ctx, sizeof(*ctx)); 249 ctx_unmap.entries = end; 250 apei_exec_post_unmap_gars(&ctx_unmap); 251 } 252 253 return rc; 254} 255EXPORT_SYMBOL_GPL(apei_exec_pre_map_gars); 256 257static int post_unmap_gar_callback(struct apei_exec_context *ctx, 258 struct acpi_whea_header *entry, 259 void *data) 260{ 261 u8 ins = entry->instruction; 262 263 if (ctx->ins_table[ins].flags & APEI_EXEC_INS_ACCESS_REGISTER) 264 apei_unmap_generic_address(&entry->register_region); 265 266 return 0; 267} 268 269/* Post-unmap all GAR in action table. */ 270int apei_exec_post_unmap_gars(struct apei_exec_context *ctx) 271{ 272 return apei_exec_for_each_entry(ctx, post_unmap_gar_callback, 273 NULL, NULL); 274} 275EXPORT_SYMBOL_GPL(apei_exec_post_unmap_gars); 276 277/* 278 * Resource management for GARs in APEI 279 */ 280struct apei_res { 281 struct list_head list; 282 unsigned long start; 283 unsigned long end; 284}; 285 286/* Collect all resources requested, to avoid conflict */ 287static struct apei_resources apei_resources_all = { 288 .iomem = LIST_HEAD_INIT(apei_resources_all.iomem), 289 .ioport = LIST_HEAD_INIT(apei_resources_all.ioport), 290}; 291 292static int apei_res_add(struct list_head *res_list, 293 unsigned long start, unsigned long size) 294{ 295 struct apei_res *res, *resn, *res_ins = NULL; 296 unsigned long end = start + size; 297 298 if (end <= start) 299 return 0; 300repeat: 301 list_for_each_entry_safe(res, resn, res_list, list) { 302 if (res->start > end || res->end < start) 303 continue; 304 else if (end <= res->end && start >= res->start) { 305 kfree(res_ins); 306 return 0; 307 } 308 list_del(&res->list); 309 res->start = start = min(res->start, start); 310 res->end = end = max(res->end, end); 311 kfree(res_ins); 312 res_ins = res; 313 goto repeat; 314 } 315 316 if (res_ins) 317 list_add(&res_ins->list, res_list); 318 else { 319 res_ins = kmalloc(sizeof(*res_ins), GFP_KERNEL); 320 if (!res_ins) 321 return -ENOMEM; 322 res_ins->start = start; 323 res_ins->end = end; 324 list_add(&res_ins->list, res_list); 325 } 326 327 return 0; 328} 329 330static int apei_res_sub(struct list_head *res_list1, 331 struct list_head *res_list2) 332{ 333 struct apei_res *res1, *resn1, *res2, *res; 334 res1 = list_entry(res_list1->next, struct apei_res, list); 335 resn1 = list_entry(res1->list.next, struct apei_res, list); 336 while (&res1->list != res_list1) { 337 list_for_each_entry(res2, res_list2, list) { 338 if (res1->start >= res2->end || 339 res1->end <= res2->start) 340 continue; 341 else if (res1->end <= res2->end && 342 res1->start >= res2->start) { 343 list_del(&res1->list); 344 kfree(res1); 345 break; 346 } else if (res1->end > res2->end && 347 res1->start < res2->start) { 348 res = kmalloc(sizeof(*res), GFP_KERNEL); 349 if (!res) 350 return -ENOMEM; 351 res->start = res2->end; 352 res->end = res1->end; 353 res1->end = res2->start; 354 list_add(&res->list, &res1->list); 355 resn1 = res; 356 } else { 357 if (res1->start < res2->start) 358 res1->end = res2->start; 359 else 360 res1->start = res2->end; 361 } 362 } 363 res1 = resn1; 364 resn1 = list_entry(resn1->list.next, struct apei_res, list); 365 } 366 367 return 0; 368} 369 370static void apei_res_clean(struct list_head *res_list) 371{ 372 struct apei_res *res, *resn; 373 374 list_for_each_entry_safe(res, resn, res_list, list) { 375 list_del(&res->list); 376 kfree(res); 377 } 378} 379 380void apei_resources_fini(struct apei_resources *resources) 381{ 382 apei_res_clean(&resources->iomem); 383 apei_res_clean(&resources->ioport); 384} 385EXPORT_SYMBOL_GPL(apei_resources_fini); 386 387static int apei_resources_merge(struct apei_resources *resources1, 388 struct apei_resources *resources2) 389{ 390 int rc; 391 struct apei_res *res; 392 393 list_for_each_entry(res, &resources2->iomem, list) { 394 rc = apei_res_add(&resources1->iomem, res->start, 395 res->end - res->start); 396 if (rc) 397 return rc; 398 } 399 list_for_each_entry(res, &resources2->ioport, list) { 400 rc = apei_res_add(&resources1->ioport, res->start, 401 res->end - res->start); 402 if (rc) 403 return rc; 404 } 405 406 return 0; 407} 408 409int apei_resources_add(struct apei_resources *resources, 410 unsigned long start, unsigned long size, 411 bool iomem) 412{ 413 if (iomem) 414 return apei_res_add(&resources->iomem, start, size); 415 else 416 return apei_res_add(&resources->ioport, start, size); 417} 418EXPORT_SYMBOL_GPL(apei_resources_add); 419 420/* 421 * EINJ has two groups of GARs (EINJ table entry and trigger table 422 * entry), so common resources are subtracted from the trigger table 423 * resources before the second requesting. 424 */ 425int apei_resources_sub(struct apei_resources *resources1, 426 struct apei_resources *resources2) 427{ 428 int rc; 429 430 rc = apei_res_sub(&resources1->iomem, &resources2->iomem); 431 if (rc) 432 return rc; 433 return apei_res_sub(&resources1->ioport, &resources2->ioport); 434} 435EXPORT_SYMBOL_GPL(apei_resources_sub); 436 437static int apei_get_res_callback(__u64 start, __u64 size, void *data) 438{ 439 struct apei_resources *resources = data; 440 return apei_res_add(&resources->iomem, start, size); 441} 442 443static int apei_get_nvs_resources(struct apei_resources *resources) 444{ 445 return acpi_nvs_for_each_region(apei_get_res_callback, resources); 446} 447 448int (*arch_apei_filter_addr)(int (*func)(__u64 start, __u64 size, 449 void *data), void *data); 450static int apei_get_arch_resources(struct apei_resources *resources) 451 452{ 453 return arch_apei_filter_addr(apei_get_res_callback, resources); 454} 455 456/* 457 * IO memory/port resource management mechanism is used to check 458 * whether memory/port area used by GARs conflicts with normal memory 459 * or IO memory/port of devices. 460 */ 461int apei_resources_request(struct apei_resources *resources, 462 const char *desc) 463{ 464 struct apei_res *res, *res_bak = NULL; 465 struct resource *r; 466 struct apei_resources nvs_resources, arch_res; 467 int rc; 468 469 rc = apei_resources_sub(resources, &apei_resources_all); 470 if (rc) 471 return rc; 472 473 /* 474 * Some firmware uses ACPI NVS region, that has been marked as 475 * busy, so exclude it from APEI resources to avoid false 476 * conflict. 477 */ 478 apei_resources_init(&nvs_resources); 479 rc = apei_get_nvs_resources(&nvs_resources); 480 if (rc) 481 goto nvs_res_fini; 482 rc = apei_resources_sub(resources, &nvs_resources); 483 if (rc) 484 goto nvs_res_fini; 485 486 if (arch_apei_filter_addr) { 487 apei_resources_init(&arch_res); 488 rc = apei_get_arch_resources(&arch_res); 489 if (rc) 490 goto arch_res_fini; 491 rc = apei_resources_sub(resources, &arch_res); 492 if (rc) 493 goto arch_res_fini; 494 } 495 496 rc = -EINVAL; 497 list_for_each_entry(res, &resources->iomem, list) { 498 r = request_mem_region(res->start, res->end - res->start, 499 desc); 500 if (!r) { 501 pr_err(APEI_PFX 502 "Can not request [mem %#010llx-%#010llx] for %s registers\n", 503 (unsigned long long)res->start, 504 (unsigned long long)res->end - 1, desc); 505 res_bak = res; 506 goto err_unmap_iomem; 507 } 508 } 509 510 list_for_each_entry(res, &resources->ioport, list) { 511 r = request_region(res->start, res->end - res->start, desc); 512 if (!r) { 513 pr_err(APEI_PFX 514 "Can not request [io %#06llx-%#06llx] for %s registers\n", 515 (unsigned long long)res->start, 516 (unsigned long long)res->end - 1, desc); 517 res_bak = res; 518 goto err_unmap_ioport; 519 } 520 } 521 522 rc = apei_resources_merge(&apei_resources_all, resources); 523 if (rc) { 524 pr_err(APEI_PFX "Fail to merge resources!\n"); 525 goto err_unmap_ioport; 526 } 527 528 goto arch_res_fini; 529 530err_unmap_ioport: 531 list_for_each_entry(res, &resources->ioport, list) { 532 if (res == res_bak) 533 break; 534 release_region(res->start, res->end - res->start); 535 } 536 res_bak = NULL; 537err_unmap_iomem: 538 list_for_each_entry(res, &resources->iomem, list) { 539 if (res == res_bak) 540 break; 541 release_mem_region(res->start, res->end - res->start); 542 } 543arch_res_fini: 544 if (arch_apei_filter_addr) 545 apei_resources_fini(&arch_res); 546nvs_res_fini: 547 apei_resources_fini(&nvs_resources); 548 return rc; 549} 550EXPORT_SYMBOL_GPL(apei_resources_request); 551 552void apei_resources_release(struct apei_resources *resources) 553{ 554 int rc; 555 struct apei_res *res; 556 557 list_for_each_entry(res, &resources->iomem, list) 558 release_mem_region(res->start, res->end - res->start); 559 list_for_each_entry(res, &resources->ioport, list) 560 release_region(res->start, res->end - res->start); 561 562 rc = apei_resources_sub(&apei_resources_all, resources); 563 if (rc) 564 pr_err(APEI_PFX "Fail to sub resources!\n"); 565} 566EXPORT_SYMBOL_GPL(apei_resources_release); 567 568static int apei_check_gar(struct acpi_generic_address *reg, u64 *paddr, 569 u32 *access_bit_width) 570{ 571 u32 bit_width, bit_offset, access_size_code, space_id; 572 573 bit_width = reg->bit_width; 574 bit_offset = reg->bit_offset; 575 access_size_code = reg->access_width; 576 space_id = reg->space_id; 577 *paddr = get_unaligned(®->address); 578 if (!*paddr) { 579 pr_warn(FW_BUG APEI_PFX 580 "Invalid physical address in GAR [0x%llx/%u/%u/%u/%u]\n", 581 *paddr, bit_width, bit_offset, access_size_code, 582 space_id); 583 return -EINVAL; 584 } 585 586 if (access_size_code < 1 || access_size_code > 4) { 587 pr_warn(FW_BUG APEI_PFX 588 "Invalid access size code in GAR [0x%llx/%u/%u/%u/%u]\n", 589 *paddr, bit_width, bit_offset, access_size_code, 590 space_id); 591 return -EINVAL; 592 } 593 *access_bit_width = 1UL << (access_size_code + 2); 594 595 /* Fixup common BIOS bug */ 596 if (bit_width == 32 && bit_offset == 0 && (*paddr & 0x03) == 0 && 597 *access_bit_width < 32) 598 *access_bit_width = 32; 599 else if (bit_width == 64 && bit_offset == 0 && (*paddr & 0x07) == 0 && 600 *access_bit_width < 64) 601 *access_bit_width = 64; 602 603 if ((bit_width + bit_offset) > *access_bit_width) { 604 pr_warn(FW_BUG APEI_PFX 605 "Invalid bit width + offset in GAR [0x%llx/%u/%u/%u/%u]\n", 606 *paddr, bit_width, bit_offset, access_size_code, 607 space_id); 608 return -EINVAL; 609 } 610 611 if (space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY && 612 space_id != ACPI_ADR_SPACE_SYSTEM_IO) { 613 pr_warn(FW_BUG APEI_PFX 614 "Invalid address space type in GAR [0x%llx/%u/%u/%u/%u]\n", 615 *paddr, bit_width, bit_offset, access_size_code, 616 space_id); 617 return -EINVAL; 618 } 619 620 return 0; 621} 622 623int apei_map_generic_address(struct acpi_generic_address *reg) 624{ 625 int rc; 626 u32 access_bit_width; 627 u64 address; 628 629 rc = apei_check_gar(reg, &address, &access_bit_width); 630 if (rc) 631 return rc; 632 633 /* IO space doesn't need mapping */ 634 if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) 635 return 0; 636 637 if (!acpi_os_map_generic_address(reg)) 638 return -ENXIO; 639 640 return 0; 641} 642EXPORT_SYMBOL_GPL(apei_map_generic_address); 643 644/* read GAR in interrupt (including NMI) or process context */ 645int apei_read(u64 *val, struct acpi_generic_address *reg) 646{ 647 int rc; 648 u32 access_bit_width; 649 u64 address; 650 acpi_status status; 651 652 rc = apei_check_gar(reg, &address, &access_bit_width); 653 if (rc) 654 return rc; 655 656 *val = 0; 657 switch(reg->space_id) { 658 case ACPI_ADR_SPACE_SYSTEM_MEMORY: 659 status = acpi_os_read_memory((acpi_physical_address) address, 660 val, access_bit_width); 661 if (ACPI_FAILURE(status)) 662 return -EIO; 663 break; 664 case ACPI_ADR_SPACE_SYSTEM_IO: 665 status = acpi_os_read_port(address, (u32 *)val, 666 access_bit_width); 667 if (ACPI_FAILURE(status)) 668 return -EIO; 669 break; 670 default: 671 return -EINVAL; 672 } 673 674 return 0; 675} 676EXPORT_SYMBOL_GPL(apei_read); 677 678/* write GAR in interrupt (including NMI) or process context */ 679int apei_write(u64 val, struct acpi_generic_address *reg) 680{ 681 int rc; 682 u32 access_bit_width; 683 u64 address; 684 acpi_status status; 685 686 rc = apei_check_gar(reg, &address, &access_bit_width); 687 if (rc) 688 return rc; 689 690 switch (reg->space_id) { 691 case ACPI_ADR_SPACE_SYSTEM_MEMORY: 692 status = acpi_os_write_memory((acpi_physical_address) address, 693 val, access_bit_width); 694 if (ACPI_FAILURE(status)) 695 return -EIO; 696 break; 697 case ACPI_ADR_SPACE_SYSTEM_IO: 698 status = acpi_os_write_port(address, val, access_bit_width); 699 if (ACPI_FAILURE(status)) 700 return -EIO; 701 break; 702 default: 703 return -EINVAL; 704 } 705 706 return 0; 707} 708EXPORT_SYMBOL_GPL(apei_write); 709 710static int collect_res_callback(struct apei_exec_context *ctx, 711 struct acpi_whea_header *entry, 712 void *data) 713{ 714 struct apei_resources *resources = data; 715 struct acpi_generic_address *reg = &entry->register_region; 716 u8 ins = entry->instruction; 717 u32 access_bit_width; 718 u64 paddr; 719 int rc; 720 721 if (!(ctx->ins_table[ins].flags & APEI_EXEC_INS_ACCESS_REGISTER)) 722 return 0; 723 724 rc = apei_check_gar(reg, &paddr, &access_bit_width); 725 if (rc) 726 return rc; 727 728 switch (reg->space_id) { 729 case ACPI_ADR_SPACE_SYSTEM_MEMORY: 730 return apei_res_add(&resources->iomem, paddr, 731 access_bit_width / 8); 732 case ACPI_ADR_SPACE_SYSTEM_IO: 733 return apei_res_add(&resources->ioport, paddr, 734 access_bit_width / 8); 735 default: 736 return -EINVAL; 737 } 738} 739 740/* 741 * Same register may be used by multiple instructions in GARs, so 742 * resources are collected before requesting. 743 */ 744int apei_exec_collect_resources(struct apei_exec_context *ctx, 745 struct apei_resources *resources) 746{ 747 return apei_exec_for_each_entry(ctx, collect_res_callback, 748 resources, NULL); 749} 750EXPORT_SYMBOL_GPL(apei_exec_collect_resources); 751 752struct dentry *apei_get_debugfs_dir(void) 753{ 754 static struct dentry *dapei; 755 756 if (!dapei) 757 dapei = debugfs_create_dir("apei", NULL); 758 759 return dapei; 760} 761EXPORT_SYMBOL_GPL(apei_get_debugfs_dir); 762 763int __weak arch_apei_enable_cmcff(struct acpi_hest_header *hest_hdr, 764 void *data) 765{ 766 return 1; 767} 768EXPORT_SYMBOL_GPL(arch_apei_enable_cmcff); 769 770void __weak arch_apei_report_mem_error(int sev, 771 struct cper_sec_mem_err *mem_err) 772{ 773} 774EXPORT_SYMBOL_GPL(arch_apei_report_mem_error); 775 776int apei_osc_setup(void) 777{ 778 static u8 whea_uuid_str[] = "ed855e0c-6c90-47bf-a62a-26de0fc5ad5c"; 779 acpi_handle handle; 780 u32 capbuf[3]; 781 struct acpi_osc_context context = { 782 .uuid_str = whea_uuid_str, 783 .rev = 1, 784 .cap.length = sizeof(capbuf), 785 .cap.pointer = capbuf, 786 }; 787 788 capbuf[OSC_QUERY_DWORD] = OSC_QUERY_ENABLE; 789 capbuf[OSC_SUPPORT_DWORD] = 1; 790 capbuf[OSC_CONTROL_DWORD] = 0; 791 792 if (ACPI_FAILURE(acpi_get_handle(NULL, "\\_SB", &handle)) 793 || ACPI_FAILURE(acpi_run_osc(handle, &context))) 794 return -EIO; 795 else { 796 kfree(context.ret.pointer); 797 return 0; 798 } 799} 800EXPORT_SYMBOL_GPL(apei_osc_setup); 801