linux/drivers/acpi/apei/erst.c
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   1/*
   2 * APEI Error Record Serialization Table support
   3 *
   4 * ERST is a way provided by APEI to save and retrieve hardware error
   5 * information to and from a persistent store.
   6 *
   7 * For more information about ERST, please refer to ACPI Specification
   8 * version 4.0, section 17.4.
   9 *
  10 * Copyright 2010 Intel Corp.
  11 *   Author: Huang Ying <ying.huang@intel.com>
  12 *
  13 * This program is free software; you can redistribute it and/or
  14 * modify it under the terms of the GNU General Public License version
  15 * 2 as published by the Free Software Foundation.
  16 *
  17 * This program is distributed in the hope that it will be useful,
  18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 * GNU General Public License for more details.
  21 */
  22
  23#include <linux/kernel.h>
  24#include <linux/module.h>
  25#include <linux/init.h>
  26#include <linux/delay.h>
  27#include <linux/io.h>
  28#include <linux/acpi.h>
  29#include <linux/uaccess.h>
  30#include <linux/cper.h>
  31#include <linux/nmi.h>
  32#include <linux/hardirq.h>
  33#include <linux/pstore.h>
  34#include <linux/vmalloc.h>
  35#include <linux/mm.h> /* kvfree() */
  36#include <acpi/apei.h>
  37
  38#include "apei-internal.h"
  39
  40#undef pr_fmt
  41#define pr_fmt(fmt) "ERST: " fmt
  42
  43/* ERST command status */
  44#define ERST_STATUS_SUCCESS                     0x0
  45#define ERST_STATUS_NOT_ENOUGH_SPACE            0x1
  46#define ERST_STATUS_HARDWARE_NOT_AVAILABLE      0x2
  47#define ERST_STATUS_FAILED                      0x3
  48#define ERST_STATUS_RECORD_STORE_EMPTY          0x4
  49#define ERST_STATUS_RECORD_NOT_FOUND            0x5
  50
  51#define ERST_TAB_ENTRY(tab)                                             \
  52        ((struct acpi_whea_header *)((char *)(tab) +                    \
  53                                     sizeof(struct acpi_table_erst)))
  54
  55#define SPIN_UNIT               100                     /* 100ns */
  56/* Firmware should respond within 1 milliseconds */
  57#define FIRMWARE_TIMEOUT        (1 * NSEC_PER_MSEC)
  58#define FIRMWARE_MAX_STALL      50                      /* 50us */
  59
  60int erst_disable;
  61EXPORT_SYMBOL_GPL(erst_disable);
  62
  63static struct acpi_table_erst *erst_tab;
  64
  65/* ERST Error Log Address Range atrributes */
  66#define ERST_RANGE_RESERVED     0x0001
  67#define ERST_RANGE_NVRAM        0x0002
  68#define ERST_RANGE_SLOW         0x0004
  69
  70/*
  71 * ERST Error Log Address Range, used as buffer for reading/writing
  72 * error records.
  73 */
  74static struct erst_erange {
  75        u64 base;
  76        u64 size;
  77        void __iomem *vaddr;
  78        u32 attr;
  79} erst_erange;
  80
  81/*
  82 * Prevent ERST interpreter to run simultaneously, because the
  83 * corresponding firmware implementation may not work properly when
  84 * invoked simultaneously.
  85 *
  86 * It is used to provide exclusive accessing for ERST Error Log
  87 * Address Range too.
  88 */
  89static DEFINE_RAW_SPINLOCK(erst_lock);
  90
  91static inline int erst_errno(int command_status)
  92{
  93        switch (command_status) {
  94        case ERST_STATUS_SUCCESS:
  95                return 0;
  96        case ERST_STATUS_HARDWARE_NOT_AVAILABLE:
  97                return -ENODEV;
  98        case ERST_STATUS_NOT_ENOUGH_SPACE:
  99                return -ENOSPC;
 100        case ERST_STATUS_RECORD_STORE_EMPTY:
 101        case ERST_STATUS_RECORD_NOT_FOUND:
 102                return -ENOENT;
 103        default:
 104                return -EINVAL;
 105        }
 106}
 107
 108static int erst_timedout(u64 *t, u64 spin_unit)
 109{
 110        if ((s64)*t < spin_unit) {
 111                pr_warn(FW_WARN "Firmware does not respond in time.\n");
 112                return 1;
 113        }
 114        *t -= spin_unit;
 115        ndelay(spin_unit);
 116        touch_nmi_watchdog();
 117        return 0;
 118}
 119
 120static int erst_exec_load_var1(struct apei_exec_context *ctx,
 121                               struct acpi_whea_header *entry)
 122{
 123        return __apei_exec_read_register(entry, &ctx->var1);
 124}
 125
 126static int erst_exec_load_var2(struct apei_exec_context *ctx,
 127                               struct acpi_whea_header *entry)
 128{
 129        return __apei_exec_read_register(entry, &ctx->var2);
 130}
 131
 132static int erst_exec_store_var1(struct apei_exec_context *ctx,
 133                                struct acpi_whea_header *entry)
 134{
 135        return __apei_exec_write_register(entry, ctx->var1);
 136}
 137
 138static int erst_exec_add(struct apei_exec_context *ctx,
 139                         struct acpi_whea_header *entry)
 140{
 141        ctx->var1 += ctx->var2;
 142        return 0;
 143}
 144
 145static int erst_exec_subtract(struct apei_exec_context *ctx,
 146                              struct acpi_whea_header *entry)
 147{
 148        ctx->var1 -= ctx->var2;
 149        return 0;
 150}
 151
 152static int erst_exec_add_value(struct apei_exec_context *ctx,
 153                               struct acpi_whea_header *entry)
 154{
 155        int rc;
 156        u64 val;
 157
 158        rc = __apei_exec_read_register(entry, &val);
 159        if (rc)
 160                return rc;
 161        val += ctx->value;
 162        rc = __apei_exec_write_register(entry, val);
 163        return rc;
 164}
 165
 166static int erst_exec_subtract_value(struct apei_exec_context *ctx,
 167                                    struct acpi_whea_header *entry)
 168{
 169        int rc;
 170        u64 val;
 171
 172        rc = __apei_exec_read_register(entry, &val);
 173        if (rc)
 174                return rc;
 175        val -= ctx->value;
 176        rc = __apei_exec_write_register(entry, val);
 177        return rc;
 178}
 179
 180static int erst_exec_stall(struct apei_exec_context *ctx,
 181                           struct acpi_whea_header *entry)
 182{
 183        u64 stall_time;
 184
 185        if (ctx->value > FIRMWARE_MAX_STALL) {
 186                if (!in_nmi())
 187                        pr_warn(FW_WARN
 188                        "Too long stall time for stall instruction: 0x%llx.\n",
 189                                   ctx->value);
 190                stall_time = FIRMWARE_MAX_STALL;
 191        } else
 192                stall_time = ctx->value;
 193        udelay(stall_time);
 194        return 0;
 195}
 196
 197static int erst_exec_stall_while_true(struct apei_exec_context *ctx,
 198                                      struct acpi_whea_header *entry)
 199{
 200        int rc;
 201        u64 val;
 202        u64 timeout = FIRMWARE_TIMEOUT;
 203        u64 stall_time;
 204
 205        if (ctx->var1 > FIRMWARE_MAX_STALL) {
 206                if (!in_nmi())
 207                        pr_warn(FW_WARN
 208                "Too long stall time for stall while true instruction: 0x%llx.\n",
 209                                   ctx->var1);
 210                stall_time = FIRMWARE_MAX_STALL;
 211        } else
 212                stall_time = ctx->var1;
 213
 214        for (;;) {
 215                rc = __apei_exec_read_register(entry, &val);
 216                if (rc)
 217                        return rc;
 218                if (val != ctx->value)
 219                        break;
 220                if (erst_timedout(&timeout, stall_time * NSEC_PER_USEC))
 221                        return -EIO;
 222        }
 223        return 0;
 224}
 225
 226static int erst_exec_skip_next_instruction_if_true(
 227        struct apei_exec_context *ctx,
 228        struct acpi_whea_header *entry)
 229{
 230        int rc;
 231        u64 val;
 232
 233        rc = __apei_exec_read_register(entry, &val);
 234        if (rc)
 235                return rc;
 236        if (val == ctx->value) {
 237                ctx->ip += 2;
 238                return APEI_EXEC_SET_IP;
 239        }
 240
 241        return 0;
 242}
 243
 244static int erst_exec_goto(struct apei_exec_context *ctx,
 245                          struct acpi_whea_header *entry)
 246{
 247        ctx->ip = ctx->value;
 248        return APEI_EXEC_SET_IP;
 249}
 250
 251static int erst_exec_set_src_address_base(struct apei_exec_context *ctx,
 252                                          struct acpi_whea_header *entry)
 253{
 254        return __apei_exec_read_register(entry, &ctx->src_base);
 255}
 256
 257static int erst_exec_set_dst_address_base(struct apei_exec_context *ctx,
 258                                          struct acpi_whea_header *entry)
 259{
 260        return __apei_exec_read_register(entry, &ctx->dst_base);
 261}
 262
 263static int erst_exec_move_data(struct apei_exec_context *ctx,
 264                               struct acpi_whea_header *entry)
 265{
 266        int rc;
 267        u64 offset;
 268        void *src, *dst;
 269
 270        /* ioremap does not work in interrupt context */
 271        if (in_interrupt()) {
 272                pr_warn("MOVE_DATA can not be used in interrupt context.\n");
 273                return -EBUSY;
 274        }
 275
 276        rc = __apei_exec_read_register(entry, &offset);
 277        if (rc)
 278                return rc;
 279
 280        src = ioremap(ctx->src_base + offset, ctx->var2);
 281        if (!src)
 282                return -ENOMEM;
 283        dst = ioremap(ctx->dst_base + offset, ctx->var2);
 284        if (!dst) {
 285                iounmap(src);
 286                return -ENOMEM;
 287        }
 288
 289        memmove(dst, src, ctx->var2);
 290
 291        iounmap(src);
 292        iounmap(dst);
 293
 294        return 0;
 295}
 296
 297static struct apei_exec_ins_type erst_ins_type[] = {
 298        [ACPI_ERST_READ_REGISTER] = {
 299                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 300                .run = apei_exec_read_register,
 301        },
 302        [ACPI_ERST_READ_REGISTER_VALUE] = {
 303                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 304                .run = apei_exec_read_register_value,
 305        },
 306        [ACPI_ERST_WRITE_REGISTER] = {
 307                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 308                .run = apei_exec_write_register,
 309        },
 310        [ACPI_ERST_WRITE_REGISTER_VALUE] = {
 311                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 312                .run = apei_exec_write_register_value,
 313        },
 314        [ACPI_ERST_NOOP] = {
 315                .flags = 0,
 316                .run = apei_exec_noop,
 317        },
 318        [ACPI_ERST_LOAD_VAR1] = {
 319                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 320                .run = erst_exec_load_var1,
 321        },
 322        [ACPI_ERST_LOAD_VAR2] = {
 323                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 324                .run = erst_exec_load_var2,
 325        },
 326        [ACPI_ERST_STORE_VAR1] = {
 327                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 328                .run = erst_exec_store_var1,
 329        },
 330        [ACPI_ERST_ADD] = {
 331                .flags = 0,
 332                .run = erst_exec_add,
 333        },
 334        [ACPI_ERST_SUBTRACT] = {
 335                .flags = 0,
 336                .run = erst_exec_subtract,
 337        },
 338        [ACPI_ERST_ADD_VALUE] = {
 339                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 340                .run = erst_exec_add_value,
 341        },
 342        [ACPI_ERST_SUBTRACT_VALUE] = {
 343                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 344                .run = erst_exec_subtract_value,
 345        },
 346        [ACPI_ERST_STALL] = {
 347                .flags = 0,
 348                .run = erst_exec_stall,
 349        },
 350        [ACPI_ERST_STALL_WHILE_TRUE] = {
 351                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 352                .run = erst_exec_stall_while_true,
 353        },
 354        [ACPI_ERST_SKIP_NEXT_IF_TRUE] = {
 355                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 356                .run = erst_exec_skip_next_instruction_if_true,
 357        },
 358        [ACPI_ERST_GOTO] = {
 359                .flags = 0,
 360                .run = erst_exec_goto,
 361        },
 362        [ACPI_ERST_SET_SRC_ADDRESS_BASE] = {
 363                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 364                .run = erst_exec_set_src_address_base,
 365        },
 366        [ACPI_ERST_SET_DST_ADDRESS_BASE] = {
 367                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 368                .run = erst_exec_set_dst_address_base,
 369        },
 370        [ACPI_ERST_MOVE_DATA] = {
 371                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 372                .run = erst_exec_move_data,
 373        },
 374};
 375
 376static inline void erst_exec_ctx_init(struct apei_exec_context *ctx)
 377{
 378        apei_exec_ctx_init(ctx, erst_ins_type, ARRAY_SIZE(erst_ins_type),
 379                           ERST_TAB_ENTRY(erst_tab), erst_tab->entries);
 380}
 381
 382static int erst_get_erange(struct erst_erange *range)
 383{
 384        struct apei_exec_context ctx;
 385        int rc;
 386
 387        erst_exec_ctx_init(&ctx);
 388        rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_RANGE);
 389        if (rc)
 390                return rc;
 391        range->base = apei_exec_ctx_get_output(&ctx);
 392        rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_LENGTH);
 393        if (rc)
 394                return rc;
 395        range->size = apei_exec_ctx_get_output(&ctx);
 396        rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_ATTRIBUTES);
 397        if (rc)
 398                return rc;
 399        range->attr = apei_exec_ctx_get_output(&ctx);
 400
 401        return 0;
 402}
 403
 404static ssize_t __erst_get_record_count(void)
 405{
 406        struct apei_exec_context ctx;
 407        int rc;
 408
 409        erst_exec_ctx_init(&ctx);
 410        rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_COUNT);
 411        if (rc)
 412                return rc;
 413        return apei_exec_ctx_get_output(&ctx);
 414}
 415
 416ssize_t erst_get_record_count(void)
 417{
 418        ssize_t count;
 419        unsigned long flags;
 420
 421        if (erst_disable)
 422                return -ENODEV;
 423
 424        raw_spin_lock_irqsave(&erst_lock, flags);
 425        count = __erst_get_record_count();
 426        raw_spin_unlock_irqrestore(&erst_lock, flags);
 427
 428        return count;
 429}
 430EXPORT_SYMBOL_GPL(erst_get_record_count);
 431
 432#define ERST_RECORD_ID_CACHE_SIZE_MIN   16
 433#define ERST_RECORD_ID_CACHE_SIZE_MAX   1024
 434
 435struct erst_record_id_cache {
 436        struct mutex lock;
 437        u64 *entries;
 438        int len;
 439        int size;
 440        int refcount;
 441};
 442
 443static struct erst_record_id_cache erst_record_id_cache = {
 444        .lock = __MUTEX_INITIALIZER(erst_record_id_cache.lock),
 445        .refcount = 0,
 446};
 447
 448static int __erst_get_next_record_id(u64 *record_id)
 449{
 450        struct apei_exec_context ctx;
 451        int rc;
 452
 453        erst_exec_ctx_init(&ctx);
 454        rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_ID);
 455        if (rc)
 456                return rc;
 457        *record_id = apei_exec_ctx_get_output(&ctx);
 458
 459        return 0;
 460}
 461
 462int erst_get_record_id_begin(int *pos)
 463{
 464        int rc;
 465
 466        if (erst_disable)
 467                return -ENODEV;
 468
 469        rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
 470        if (rc)
 471                return rc;
 472        erst_record_id_cache.refcount++;
 473        mutex_unlock(&erst_record_id_cache.lock);
 474
 475        *pos = 0;
 476
 477        return 0;
 478}
 479EXPORT_SYMBOL_GPL(erst_get_record_id_begin);
 480
 481/* erst_record_id_cache.lock must be held by caller */
 482static int __erst_record_id_cache_add_one(void)
 483{
 484        u64 id, prev_id, first_id;
 485        int i, rc;
 486        u64 *entries;
 487        unsigned long flags;
 488
 489        id = prev_id = first_id = APEI_ERST_INVALID_RECORD_ID;
 490retry:
 491        raw_spin_lock_irqsave(&erst_lock, flags);
 492        rc = __erst_get_next_record_id(&id);
 493        raw_spin_unlock_irqrestore(&erst_lock, flags);
 494        if (rc == -ENOENT)
 495                return 0;
 496        if (rc)
 497                return rc;
 498        if (id == APEI_ERST_INVALID_RECORD_ID)
 499                return 0;
 500        /* can not skip current ID, or loop back to first ID */
 501        if (id == prev_id || id == first_id)
 502                return 0;
 503        if (first_id == APEI_ERST_INVALID_RECORD_ID)
 504                first_id = id;
 505        prev_id = id;
 506
 507        entries = erst_record_id_cache.entries;
 508        for (i = 0; i < erst_record_id_cache.len; i++) {
 509                if (entries[i] == id)
 510                        break;
 511        }
 512        /* record id already in cache, try next */
 513        if (i < erst_record_id_cache.len)
 514                goto retry;
 515        if (erst_record_id_cache.len >= erst_record_id_cache.size) {
 516                int new_size, alloc_size;
 517                u64 *new_entries;
 518
 519                new_size = erst_record_id_cache.size * 2;
 520                new_size = clamp_val(new_size, ERST_RECORD_ID_CACHE_SIZE_MIN,
 521                                     ERST_RECORD_ID_CACHE_SIZE_MAX);
 522                if (new_size <= erst_record_id_cache.size) {
 523                        if (printk_ratelimit())
 524                                pr_warn(FW_WARN "too many record IDs!\n");
 525                        return 0;
 526                }
 527                alloc_size = new_size * sizeof(entries[0]);
 528                if (alloc_size < PAGE_SIZE)
 529                        new_entries = kmalloc(alloc_size, GFP_KERNEL);
 530                else
 531                        new_entries = vmalloc(alloc_size);
 532                if (!new_entries)
 533                        return -ENOMEM;
 534                memcpy(new_entries, entries,
 535                       erst_record_id_cache.len * sizeof(entries[0]));
 536                kvfree(entries);
 537                erst_record_id_cache.entries = entries = new_entries;
 538                erst_record_id_cache.size = new_size;
 539        }
 540        entries[i] = id;
 541        erst_record_id_cache.len++;
 542
 543        return 1;
 544}
 545
 546/*
 547 * Get the record ID of an existing error record on the persistent
 548 * storage. If there is no error record on the persistent storage, the
 549 * returned record_id is APEI_ERST_INVALID_RECORD_ID.
 550 */
 551int erst_get_record_id_next(int *pos, u64 *record_id)
 552{
 553        int rc = 0;
 554        u64 *entries;
 555
 556        if (erst_disable)
 557                return -ENODEV;
 558
 559        /* must be enclosed by erst_get_record_id_begin/end */
 560        BUG_ON(!erst_record_id_cache.refcount);
 561        BUG_ON(*pos < 0 || *pos > erst_record_id_cache.len);
 562
 563        mutex_lock(&erst_record_id_cache.lock);
 564        entries = erst_record_id_cache.entries;
 565        for (; *pos < erst_record_id_cache.len; (*pos)++)
 566                if (entries[*pos] != APEI_ERST_INVALID_RECORD_ID)
 567                        break;
 568        /* found next record id in cache */
 569        if (*pos < erst_record_id_cache.len) {
 570                *record_id = entries[*pos];
 571                (*pos)++;
 572                goto out_unlock;
 573        }
 574
 575        /* Try to add one more record ID to cache */
 576        rc = __erst_record_id_cache_add_one();
 577        if (rc < 0)
 578                goto out_unlock;
 579        /* successfully add one new ID */
 580        if (rc == 1) {
 581                *record_id = erst_record_id_cache.entries[*pos];
 582                (*pos)++;
 583                rc = 0;
 584        } else {
 585                *pos = -1;
 586                *record_id = APEI_ERST_INVALID_RECORD_ID;
 587        }
 588out_unlock:
 589        mutex_unlock(&erst_record_id_cache.lock);
 590
 591        return rc;
 592}
 593EXPORT_SYMBOL_GPL(erst_get_record_id_next);
 594
 595/* erst_record_id_cache.lock must be held by caller */
 596static void __erst_record_id_cache_compact(void)
 597{
 598        int i, wpos = 0;
 599        u64 *entries;
 600
 601        if (erst_record_id_cache.refcount)
 602                return;
 603
 604        entries = erst_record_id_cache.entries;
 605        for (i = 0; i < erst_record_id_cache.len; i++) {
 606                if (entries[i] == APEI_ERST_INVALID_RECORD_ID)
 607                        continue;
 608                if (wpos != i)
 609                        entries[wpos] = entries[i];
 610                wpos++;
 611        }
 612        erst_record_id_cache.len = wpos;
 613}
 614
 615void erst_get_record_id_end(void)
 616{
 617        /*
 618         * erst_disable != 0 should be detected by invoker via the
 619         * return value of erst_get_record_id_begin/next, so this
 620         * function should not be called for erst_disable != 0.
 621         */
 622        BUG_ON(erst_disable);
 623
 624        mutex_lock(&erst_record_id_cache.lock);
 625        erst_record_id_cache.refcount--;
 626        BUG_ON(erst_record_id_cache.refcount < 0);
 627        __erst_record_id_cache_compact();
 628        mutex_unlock(&erst_record_id_cache.lock);
 629}
 630EXPORT_SYMBOL_GPL(erst_get_record_id_end);
 631
 632static int __erst_write_to_storage(u64 offset)
 633{
 634        struct apei_exec_context ctx;
 635        u64 timeout = FIRMWARE_TIMEOUT;
 636        u64 val;
 637        int rc;
 638
 639        erst_exec_ctx_init(&ctx);
 640        rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_WRITE);
 641        if (rc)
 642                return rc;
 643        apei_exec_ctx_set_input(&ctx, offset);
 644        rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_OFFSET);
 645        if (rc)
 646                return rc;
 647        rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
 648        if (rc)
 649                return rc;
 650        for (;;) {
 651                rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
 652                if (rc)
 653                        return rc;
 654                val = apei_exec_ctx_get_output(&ctx);
 655                if (!val)
 656                        break;
 657                if (erst_timedout(&timeout, SPIN_UNIT))
 658                        return -EIO;
 659        }
 660        rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
 661        if (rc)
 662                return rc;
 663        val = apei_exec_ctx_get_output(&ctx);
 664        rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
 665        if (rc)
 666                return rc;
 667
 668        return erst_errno(val);
 669}
 670
 671static int __erst_read_from_storage(u64 record_id, u64 offset)
 672{
 673        struct apei_exec_context ctx;
 674        u64 timeout = FIRMWARE_TIMEOUT;
 675        u64 val;
 676        int rc;
 677
 678        erst_exec_ctx_init(&ctx);
 679        rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_READ);
 680        if (rc)
 681                return rc;
 682        apei_exec_ctx_set_input(&ctx, offset);
 683        rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_OFFSET);
 684        if (rc)
 685                return rc;
 686        apei_exec_ctx_set_input(&ctx, record_id);
 687        rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_ID);
 688        if (rc)
 689                return rc;
 690        rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
 691        if (rc)
 692                return rc;
 693        for (;;) {
 694                rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
 695                if (rc)
 696                        return rc;
 697                val = apei_exec_ctx_get_output(&ctx);
 698                if (!val)
 699                        break;
 700                if (erst_timedout(&timeout, SPIN_UNIT))
 701                        return -EIO;
 702        };
 703        rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
 704        if (rc)
 705                return rc;
 706        val = apei_exec_ctx_get_output(&ctx);
 707        rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
 708        if (rc)
 709                return rc;
 710
 711        return erst_errno(val);
 712}
 713
 714static int __erst_clear_from_storage(u64 record_id)
 715{
 716        struct apei_exec_context ctx;
 717        u64 timeout = FIRMWARE_TIMEOUT;
 718        u64 val;
 719        int rc;
 720
 721        erst_exec_ctx_init(&ctx);
 722        rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_CLEAR);
 723        if (rc)
 724                return rc;
 725        apei_exec_ctx_set_input(&ctx, record_id);
 726        rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_ID);
 727        if (rc)
 728                return rc;
 729        rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
 730        if (rc)
 731                return rc;
 732        for (;;) {
 733                rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
 734                if (rc)
 735                        return rc;
 736                val = apei_exec_ctx_get_output(&ctx);
 737                if (!val)
 738                        break;
 739                if (erst_timedout(&timeout, SPIN_UNIT))
 740                        return -EIO;
 741        }
 742        rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
 743        if (rc)
 744                return rc;
 745        val = apei_exec_ctx_get_output(&ctx);
 746        rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
 747        if (rc)
 748                return rc;
 749
 750        return erst_errno(val);
 751}
 752
 753/* NVRAM ERST Error Log Address Range is not supported yet */
 754static void pr_unimpl_nvram(void)
 755{
 756        if (printk_ratelimit())
 757                pr_warn("NVRAM ERST Log Address Range not implemented yet.\n");
 758}
 759
 760static int __erst_write_to_nvram(const struct cper_record_header *record)
 761{
 762        /* do not print message, because printk is not safe for NMI */
 763        return -ENOSYS;
 764}
 765
 766static int __erst_read_to_erange_from_nvram(u64 record_id, u64 *offset)
 767{
 768        pr_unimpl_nvram();
 769        return -ENOSYS;
 770}
 771
 772static int __erst_clear_from_nvram(u64 record_id)
 773{
 774        pr_unimpl_nvram();
 775        return -ENOSYS;
 776}
 777
 778int erst_write(const struct cper_record_header *record)
 779{
 780        int rc;
 781        unsigned long flags;
 782        struct cper_record_header *rcd_erange;
 783
 784        if (erst_disable)
 785                return -ENODEV;
 786
 787        if (memcmp(record->signature, CPER_SIG_RECORD, CPER_SIG_SIZE))
 788                return -EINVAL;
 789
 790        if (erst_erange.attr & ERST_RANGE_NVRAM) {
 791                if (!raw_spin_trylock_irqsave(&erst_lock, flags))
 792                        return -EBUSY;
 793                rc = __erst_write_to_nvram(record);
 794                raw_spin_unlock_irqrestore(&erst_lock, flags);
 795                return rc;
 796        }
 797
 798        if (record->record_length > erst_erange.size)
 799                return -EINVAL;
 800
 801        if (!raw_spin_trylock_irqsave(&erst_lock, flags))
 802                return -EBUSY;
 803        memcpy(erst_erange.vaddr, record, record->record_length);
 804        rcd_erange = erst_erange.vaddr;
 805        /* signature for serialization system */
 806        memcpy(&rcd_erange->persistence_information, "ER", 2);
 807
 808        rc = __erst_write_to_storage(0);
 809        raw_spin_unlock_irqrestore(&erst_lock, flags);
 810
 811        return rc;
 812}
 813EXPORT_SYMBOL_GPL(erst_write);
 814
 815static int __erst_read_to_erange(u64 record_id, u64 *offset)
 816{
 817        int rc;
 818
 819        if (erst_erange.attr & ERST_RANGE_NVRAM)
 820                return __erst_read_to_erange_from_nvram(
 821                        record_id, offset);
 822
 823        rc = __erst_read_from_storage(record_id, 0);
 824        if (rc)
 825                return rc;
 826        *offset = 0;
 827
 828        return 0;
 829}
 830
 831static ssize_t __erst_read(u64 record_id, struct cper_record_header *record,
 832                           size_t buflen)
 833{
 834        int rc;
 835        u64 offset, len = 0;
 836        struct cper_record_header *rcd_tmp;
 837
 838        rc = __erst_read_to_erange(record_id, &offset);
 839        if (rc)
 840                return rc;
 841        rcd_tmp = erst_erange.vaddr + offset;
 842        len = rcd_tmp->record_length;
 843        if (len <= buflen)
 844                memcpy(record, rcd_tmp, len);
 845
 846        return len;
 847}
 848
 849/*
 850 * If return value > buflen, the buffer size is not big enough,
 851 * else if return value < 0, something goes wrong,
 852 * else everything is OK, and return value is record length
 853 */
 854ssize_t erst_read(u64 record_id, struct cper_record_header *record,
 855                  size_t buflen)
 856{
 857        ssize_t len;
 858        unsigned long flags;
 859
 860        if (erst_disable)
 861                return -ENODEV;
 862
 863        raw_spin_lock_irqsave(&erst_lock, flags);
 864        len = __erst_read(record_id, record, buflen);
 865        raw_spin_unlock_irqrestore(&erst_lock, flags);
 866        return len;
 867}
 868EXPORT_SYMBOL_GPL(erst_read);
 869
 870int erst_clear(u64 record_id)
 871{
 872        int rc, i;
 873        unsigned long flags;
 874        u64 *entries;
 875
 876        if (erst_disable)
 877                return -ENODEV;
 878
 879        rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
 880        if (rc)
 881                return rc;
 882        raw_spin_lock_irqsave(&erst_lock, flags);
 883        if (erst_erange.attr & ERST_RANGE_NVRAM)
 884                rc = __erst_clear_from_nvram(record_id);
 885        else
 886                rc = __erst_clear_from_storage(record_id);
 887        raw_spin_unlock_irqrestore(&erst_lock, flags);
 888        if (rc)
 889                goto out;
 890        entries = erst_record_id_cache.entries;
 891        for (i = 0; i < erst_record_id_cache.len; i++) {
 892                if (entries[i] == record_id)
 893                        entries[i] = APEI_ERST_INVALID_RECORD_ID;
 894        }
 895        __erst_record_id_cache_compact();
 896out:
 897        mutex_unlock(&erst_record_id_cache.lock);
 898        return rc;
 899}
 900EXPORT_SYMBOL_GPL(erst_clear);
 901
 902static int __init setup_erst_disable(char *str)
 903{
 904        erst_disable = 1;
 905        return 0;
 906}
 907
 908__setup("erst_disable", setup_erst_disable);
 909
 910static int erst_check_table(struct acpi_table_erst *erst_tab)
 911{
 912        if ((erst_tab->header_length !=
 913             (sizeof(struct acpi_table_erst) - sizeof(erst_tab->header)))
 914            && (erst_tab->header_length != sizeof(struct acpi_table_erst)))
 915                return -EINVAL;
 916        if (erst_tab->header.length < sizeof(struct acpi_table_erst))
 917                return -EINVAL;
 918        if (erst_tab->entries !=
 919            (erst_tab->header.length - sizeof(struct acpi_table_erst)) /
 920            sizeof(struct acpi_erst_entry))
 921                return -EINVAL;
 922
 923        return 0;
 924}
 925
 926static int erst_open_pstore(struct pstore_info *psi);
 927static int erst_close_pstore(struct pstore_info *psi);
 928static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
 929                           struct timespec *time, char **buf,
 930                           bool *compressed, struct pstore_info *psi);
 931static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
 932                       u64 *id, unsigned int part, int count, bool compressed,
 933                       size_t size, struct pstore_info *psi);
 934static int erst_clearer(enum pstore_type_id type, u64 id, int count,
 935                        struct timespec time, struct pstore_info *psi);
 936
 937static struct pstore_info erst_info = {
 938        .owner          = THIS_MODULE,
 939        .name           = "erst",
 940        .flags          = PSTORE_FLAGS_FRAGILE,
 941        .open           = erst_open_pstore,
 942        .close          = erst_close_pstore,
 943        .read           = erst_reader,
 944        .write          = erst_writer,
 945        .erase          = erst_clearer
 946};
 947
 948#define CPER_CREATOR_PSTORE                                             \
 949        UUID_LE(0x75a574e3, 0x5052, 0x4b29, 0x8a, 0x8e, 0xbe, 0x2c,     \
 950                0x64, 0x90, 0xb8, 0x9d)
 951#define CPER_SECTION_TYPE_DMESG                                         \
 952        UUID_LE(0xc197e04e, 0xd545, 0x4a70, 0x9c, 0x17, 0xa5, 0x54,     \
 953                0x94, 0x19, 0xeb, 0x12)
 954#define CPER_SECTION_TYPE_DMESG_Z                                       \
 955        UUID_LE(0x4f118707, 0x04dd, 0x4055, 0xb5, 0xdd, 0x95, 0x6d,     \
 956                0x34, 0xdd, 0xfa, 0xc6)
 957#define CPER_SECTION_TYPE_MCE                                           \
 958        UUID_LE(0xfe08ffbe, 0x95e4, 0x4be7, 0xbc, 0x73, 0x40, 0x96,     \
 959                0x04, 0x4a, 0x38, 0xfc)
 960
 961struct cper_pstore_record {
 962        struct cper_record_header hdr;
 963        struct cper_section_descriptor sec_hdr;
 964        char data[];
 965} __packed;
 966
 967static int reader_pos;
 968
 969static int erst_open_pstore(struct pstore_info *psi)
 970{
 971        int rc;
 972
 973        if (erst_disable)
 974                return -ENODEV;
 975
 976        rc = erst_get_record_id_begin(&reader_pos);
 977
 978        return rc;
 979}
 980
 981static int erst_close_pstore(struct pstore_info *psi)
 982{
 983        erst_get_record_id_end();
 984
 985        return 0;
 986}
 987
 988static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
 989                           struct timespec *time, char **buf,
 990                           bool *compressed, struct pstore_info *psi)
 991{
 992        int rc;
 993        ssize_t len = 0;
 994        u64 record_id;
 995        struct cper_pstore_record *rcd;
 996        size_t rcd_len = sizeof(*rcd) + erst_info.bufsize;
 997
 998        if (erst_disable)
 999                return -ENODEV;
1000
1001        rcd = kmalloc(rcd_len, GFP_KERNEL);
1002        if (!rcd) {
1003                rc = -ENOMEM;
1004                goto out;
1005        }
1006skip:
1007        rc = erst_get_record_id_next(&reader_pos, &record_id);
1008        if (rc)
1009                goto out;
1010
1011        /* no more record */
1012        if (record_id == APEI_ERST_INVALID_RECORD_ID) {
1013                rc = -EINVAL;
1014                goto out;
1015        }
1016
1017        len = erst_read(record_id, &rcd->hdr, rcd_len);
1018        /* The record may be cleared by others, try read next record */
1019        if (len == -ENOENT)
1020                goto skip;
1021        else if (len < sizeof(*rcd)) {
1022                rc = -EIO;
1023                goto out;
1024        }
1025        if (uuid_le_cmp(rcd->hdr.creator_id, CPER_CREATOR_PSTORE) != 0)
1026                goto skip;
1027
1028        *buf = kmalloc(len, GFP_KERNEL);
1029        if (*buf == NULL) {
1030                rc = -ENOMEM;
1031                goto out;
1032        }
1033        memcpy(*buf, rcd->data, len - sizeof(*rcd));
1034        *id = record_id;
1035        *compressed = false;
1036        if (uuid_le_cmp(rcd->sec_hdr.section_type,
1037                        CPER_SECTION_TYPE_DMESG_Z) == 0) {
1038                *type = PSTORE_TYPE_DMESG;
1039                *compressed = true;
1040        } else if (uuid_le_cmp(rcd->sec_hdr.section_type,
1041                        CPER_SECTION_TYPE_DMESG) == 0)
1042                *type = PSTORE_TYPE_DMESG;
1043        else if (uuid_le_cmp(rcd->sec_hdr.section_type,
1044                             CPER_SECTION_TYPE_MCE) == 0)
1045                *type = PSTORE_TYPE_MCE;
1046        else
1047                *type = PSTORE_TYPE_UNKNOWN;
1048
1049        if (rcd->hdr.validation_bits & CPER_VALID_TIMESTAMP)
1050                time->tv_sec = rcd->hdr.timestamp;
1051        else
1052                time->tv_sec = 0;
1053        time->tv_nsec = 0;
1054
1055out:
1056        kfree(rcd);
1057        return (rc < 0) ? rc : (len - sizeof(*rcd));
1058}
1059
1060static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
1061                       u64 *id, unsigned int part, int count, bool compressed,
1062                       size_t size, struct pstore_info *psi)
1063{
1064        struct cper_pstore_record *rcd = (struct cper_pstore_record *)
1065                                        (erst_info.buf - sizeof(*rcd));
1066        int ret;
1067
1068        memset(rcd, 0, sizeof(*rcd));
1069        memcpy(rcd->hdr.signature, CPER_SIG_RECORD, CPER_SIG_SIZE);
1070        rcd->hdr.revision = CPER_RECORD_REV;
1071        rcd->hdr.signature_end = CPER_SIG_END;
1072        rcd->hdr.section_count = 1;
1073        rcd->hdr.error_severity = CPER_SEV_FATAL;
1074        /* timestamp valid. platform_id, partition_id are invalid */
1075        rcd->hdr.validation_bits = CPER_VALID_TIMESTAMP;
1076        rcd->hdr.timestamp = get_seconds();
1077        rcd->hdr.record_length = sizeof(*rcd) + size;
1078        rcd->hdr.creator_id = CPER_CREATOR_PSTORE;
1079        rcd->hdr.notification_type = CPER_NOTIFY_MCE;
1080        rcd->hdr.record_id = cper_next_record_id();
1081        rcd->hdr.flags = CPER_HW_ERROR_FLAGS_PREVERR;
1082
1083        rcd->sec_hdr.section_offset = sizeof(*rcd);
1084        rcd->sec_hdr.section_length = size;
1085        rcd->sec_hdr.revision = CPER_SEC_REV;
1086        /* fru_id and fru_text is invalid */
1087        rcd->sec_hdr.validation_bits = 0;
1088        rcd->sec_hdr.flags = CPER_SEC_PRIMARY;
1089        switch (type) {
1090        case PSTORE_TYPE_DMESG:
1091                if (compressed)
1092                        rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG_Z;
1093                else
1094                        rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG;
1095                break;
1096        case PSTORE_TYPE_MCE:
1097                rcd->sec_hdr.section_type = CPER_SECTION_TYPE_MCE;
1098                break;
1099        default:
1100                return -EINVAL;
1101        }
1102        rcd->sec_hdr.section_severity = CPER_SEV_FATAL;
1103
1104        ret = erst_write(&rcd->hdr);
1105        *id = rcd->hdr.record_id;
1106
1107        return ret;
1108}
1109
1110static int erst_clearer(enum pstore_type_id type, u64 id, int count,
1111                        struct timespec time, struct pstore_info *psi)
1112{
1113        return erst_clear(id);
1114}
1115
1116static int __init erst_init(void)
1117{
1118        int rc = 0;
1119        acpi_status status;
1120        struct apei_exec_context ctx;
1121        struct apei_resources erst_resources;
1122        struct resource *r;
1123        char *buf;
1124
1125        if (acpi_disabled)
1126                goto err;
1127
1128        if (erst_disable) {
1129                pr_info(
1130        "Error Record Serialization Table (ERST) support is disabled.\n");
1131                goto err;
1132        }
1133
1134        status = acpi_get_table(ACPI_SIG_ERST, 0,
1135                                (struct acpi_table_header **)&erst_tab);
1136        if (status == AE_NOT_FOUND)
1137                goto err;
1138        else if (ACPI_FAILURE(status)) {
1139                const char *msg = acpi_format_exception(status);
1140                pr_err("Failed to get table, %s\n", msg);
1141                rc = -EINVAL;
1142                goto err;
1143        }
1144
1145        rc = erst_check_table(erst_tab);
1146        if (rc) {
1147                pr_err(FW_BUG "ERST table is invalid.\n");
1148                goto err;
1149        }
1150
1151        apei_resources_init(&erst_resources);
1152        erst_exec_ctx_init(&ctx);
1153        rc = apei_exec_collect_resources(&ctx, &erst_resources);
1154        if (rc)
1155                goto err_fini;
1156        rc = apei_resources_request(&erst_resources, "APEI ERST");
1157        if (rc)
1158                goto err_fini;
1159        rc = apei_exec_pre_map_gars(&ctx);
1160        if (rc)
1161                goto err_release;
1162        rc = erst_get_erange(&erst_erange);
1163        if (rc) {
1164                if (rc == -ENODEV)
1165                        pr_info(
1166        "The corresponding hardware device or firmware implementation "
1167        "is not available.\n");
1168                else
1169                        pr_err("Failed to get Error Log Address Range.\n");
1170                goto err_unmap_reg;
1171        }
1172
1173        r = request_mem_region(erst_erange.base, erst_erange.size, "APEI ERST");
1174        if (!r) {
1175                pr_err("Can not request [mem %#010llx-%#010llx] for ERST.\n",
1176                       (unsigned long long)erst_erange.base,
1177                       (unsigned long long)erst_erange.base + erst_erange.size - 1);
1178                rc = -EIO;
1179                goto err_unmap_reg;
1180        }
1181        rc = -ENOMEM;
1182        erst_erange.vaddr = ioremap_cache(erst_erange.base,
1183                                          erst_erange.size);
1184        if (!erst_erange.vaddr)
1185                goto err_release_erange;
1186
1187        pr_info(
1188        "Error Record Serialization Table (ERST) support is initialized.\n");
1189
1190        buf = kmalloc(erst_erange.size, GFP_KERNEL);
1191        spin_lock_init(&erst_info.buf_lock);
1192        if (buf) {
1193                erst_info.buf = buf + sizeof(struct cper_pstore_record);
1194                erst_info.bufsize = erst_erange.size -
1195                                    sizeof(struct cper_pstore_record);
1196                rc = pstore_register(&erst_info);
1197                if (rc) {
1198                        if (rc != -EPERM)
1199                                pr_info(
1200                                "Could not register with persistent store.\n");
1201                        erst_info.buf = NULL;
1202                        erst_info.bufsize = 0;
1203                        kfree(buf);
1204                }
1205        } else
1206                pr_err(
1207                "Failed to allocate %lld bytes for persistent store error log.\n",
1208                erst_erange.size);
1209
1210        /* Cleanup ERST Resources */
1211        apei_resources_fini(&erst_resources);
1212
1213        return 0;
1214
1215err_release_erange:
1216        release_mem_region(erst_erange.base, erst_erange.size);
1217err_unmap_reg:
1218        apei_exec_post_unmap_gars(&ctx);
1219err_release:
1220        apei_resources_release(&erst_resources);
1221err_fini:
1222        apei_resources_fini(&erst_resources);
1223err:
1224        erst_disable = 1;
1225        return rc;
1226}
1227
1228device_initcall(erst_init);
1229