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