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 * You should have received a copy of the GNU General Public License
  23 * along with this program; if not, write to the Free Software
  24 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  25 */
  26
  27#include <linux/kernel.h>
  28#include <linux/module.h>
  29#include <linux/init.h>
  30#include <linux/delay.h>
  31#include <linux/io.h>
  32#include <linux/acpi.h>
  33#include <linux/uaccess.h>
  34#include <linux/cper.h>
  35#include <linux/nmi.h>
  36#include <linux/hardirq.h>
  37#include <linux/pstore.h>
  38#include <acpi/apei.h>
  39
  40#include "apei-internal.h"
  41
  42#undef pr_fmt
  43#define pr_fmt(fmt) "ERST: " fmt
  44
  45/* ERST command status */
  46#define ERST_STATUS_SUCCESS                     0x0
  47#define ERST_STATUS_NOT_ENOUGH_SPACE            0x1
  48#define ERST_STATUS_HARDWARE_NOT_AVAILABLE      0x2
  49#define ERST_STATUS_FAILED                      0x3
  50#define ERST_STATUS_RECORD_STORE_EMPTY          0x4
  51#define ERST_STATUS_RECORD_NOT_FOUND            0x5
  52
  53#define ERST_TAB_ENTRY(tab)                                             \
  54        ((struct acpi_whea_header *)((char *)(tab) +                    \
  55                                     sizeof(struct acpi_table_erst)))
  56
  57#define SPIN_UNIT               100                     /* 100ns */
  58/* Firmware should respond within 1 milliseconds */
  59#define FIRMWARE_TIMEOUT        (1 * NSEC_PER_MSEC)
  60#define FIRMWARE_MAX_STALL      50                      /* 50us */
  61
  62int erst_disable;
  63EXPORT_SYMBOL_GPL(erst_disable);
  64
  65static struct acpi_table_erst *erst_tab;
  66
  67/* ERST Error Log Address Range atrributes */
  68#define ERST_RANGE_RESERVED     0x0001
  69#define ERST_RANGE_NVRAM        0x0002
  70#define ERST_RANGE_SLOW         0x0004
  71
  72/*
  73 * ERST Error Log Address Range, used as buffer for reading/writing
  74 * error records.
  75 */
  76static struct erst_erange {
  77        u64 base;
  78        u64 size;
  79        void __iomem *vaddr;
  80        u32 attr;
  81} erst_erange;
  82
  83/*
  84 * Prevent ERST interpreter to run simultaneously, because the
  85 * corresponding firmware implementation may not work properly when
  86 * invoked simultaneously.
  87 *
  88 * It is used to provide exclusive accessing for ERST Error Log
  89 * Address Range too.
  90 */
  91static DEFINE_RAW_SPINLOCK(erst_lock);
  92
  93static inline int erst_errno(int command_status)
  94{
  95        switch (command_status) {
  96        case ERST_STATUS_SUCCESS:
  97                return 0;
  98        case ERST_STATUS_HARDWARE_NOT_AVAILABLE:
  99                return -ENODEV;
 100        case ERST_STATUS_NOT_ENOUGH_SPACE:
 101                return -ENOSPC;
 102        case ERST_STATUS_RECORD_STORE_EMPTY:
 103        case ERST_STATUS_RECORD_NOT_FOUND:
 104                return -ENOENT;
 105        default:
 106                return -EINVAL;
 107        }
 108}
 109
 110static int erst_timedout(u64 *t, u64 spin_unit)
 111{
 112        if ((s64)*t < spin_unit) {
 113                pr_warn(FW_WARN "Firmware does not respond in time.\n");
 114                return 1;
 115        }
 116        *t -= spin_unit;
 117        ndelay(spin_unit);
 118        touch_nmi_watchdog();
 119        return 0;
 120}
 121
 122static int erst_exec_load_var1(struct apei_exec_context *ctx,
 123                               struct acpi_whea_header *entry)
 124{
 125        return __apei_exec_read_register(entry, &ctx->var1);
 126}
 127
 128static int erst_exec_load_var2(struct apei_exec_context *ctx,
 129                               struct acpi_whea_header *entry)
 130{
 131        return __apei_exec_read_register(entry, &ctx->var2);
 132}
 133
 134static int erst_exec_store_var1(struct apei_exec_context *ctx,
 135                                struct acpi_whea_header *entry)
 136{
 137        return __apei_exec_write_register(entry, ctx->var1);
 138}
 139
 140static int erst_exec_add(struct apei_exec_context *ctx,
 141                         struct acpi_whea_header *entry)
 142{
 143        ctx->var1 += ctx->var2;
 144        return 0;
 145}
 146
 147static int erst_exec_subtract(struct apei_exec_context *ctx,
 148                              struct acpi_whea_header *entry)
 149{
 150        ctx->var1 -= ctx->var2;
 151        return 0;
 152}
 153
 154static int erst_exec_add_value(struct apei_exec_context *ctx,
 155                               struct acpi_whea_header *entry)
 156{
 157        int rc;
 158        u64 val;
 159
 160        rc = __apei_exec_read_register(entry, &val);
 161        if (rc)
 162                return rc;
 163        val += ctx->value;
 164        rc = __apei_exec_write_register(entry, val);
 165        return rc;
 166}
 167
 168static int erst_exec_subtract_value(struct apei_exec_context *ctx,
 169                                    struct acpi_whea_header *entry)
 170{
 171        int rc;
 172        u64 val;
 173
 174        rc = __apei_exec_read_register(entry, &val);
 175        if (rc)
 176                return rc;
 177        val -= ctx->value;
 178        rc = __apei_exec_write_register(entry, val);
 179        return rc;
 180}
 181
 182static int erst_exec_stall(struct apei_exec_context *ctx,
 183                           struct acpi_whea_header *entry)
 184{
 185        u64 stall_time;
 186
 187        if (ctx->value > FIRMWARE_MAX_STALL) {
 188                if (!in_nmi())
 189                        pr_warn(FW_WARN
 190                        "Too long stall time for stall instruction: 0x%llx.\n",
 191                                   ctx->value);
 192                stall_time = FIRMWARE_MAX_STALL;
 193        } else
 194                stall_time = ctx->value;
 195        udelay(stall_time);
 196        return 0;
 197}
 198
 199static int erst_exec_stall_while_true(struct apei_exec_context *ctx,
 200                                      struct acpi_whea_header *entry)
 201{
 202        int rc;
 203        u64 val;
 204        u64 timeout = FIRMWARE_TIMEOUT;
 205        u64 stall_time;
 206
 207        if (ctx->var1 > FIRMWARE_MAX_STALL) {
 208                if (!in_nmi())
 209                        pr_warn(FW_WARN
 210                "Too long stall time for stall while true instruction: 0x%llx.\n",
 211                                   ctx->var1);
 212                stall_time = FIRMWARE_MAX_STALL;
 213        } else
 214                stall_time = ctx->var1;
 215
 216        for (;;) {
 217                rc = __apei_exec_read_register(entry, &val);
 218                if (rc)
 219                        return rc;
 220                if (val != ctx->value)
 221                        break;
 222                if (erst_timedout(&timeout, stall_time * NSEC_PER_USEC))
 223                        return -EIO;
 224        }
 225        return 0;
 226}
 227
 228static int erst_exec_skip_next_instruction_if_true(
 229        struct apei_exec_context *ctx,
 230        struct acpi_whea_header *entry)
 231{
 232        int rc;
 233        u64 val;
 234
 235        rc = __apei_exec_read_register(entry, &val);
 236        if (rc)
 237                return rc;
 238        if (val == ctx->value) {
 239                ctx->ip += 2;
 240                return APEI_EXEC_SET_IP;
 241        }
 242
 243        return 0;
 244}
 245
 246static int erst_exec_goto(struct apei_exec_context *ctx,
 247                          struct acpi_whea_header *entry)
 248{
 249        ctx->ip = ctx->value;
 250        return APEI_EXEC_SET_IP;
 251}
 252
 253static int erst_exec_set_src_address_base(struct apei_exec_context *ctx,
 254                                          struct acpi_whea_header *entry)
 255{
 256        return __apei_exec_read_register(entry, &ctx->src_base);
 257}
 258
 259static int erst_exec_set_dst_address_base(struct apei_exec_context *ctx,
 260                                          struct acpi_whea_header *entry)
 261{
 262        return __apei_exec_read_register(entry, &ctx->dst_base);
 263}
 264
 265static int erst_exec_move_data(struct apei_exec_context *ctx,
 266                               struct acpi_whea_header *entry)
 267{
 268        int rc;
 269        u64 offset;
 270        void *src, *dst;
 271
 272        /* ioremap does not work in interrupt context */
 273        if (in_interrupt()) {
 274                pr_warn("MOVE_DATA can not be used in interrupt context.\n");
 275                return -EBUSY;
 276        }
 277
 278        rc = __apei_exec_read_register(entry, &offset);
 279        if (rc)
 280                return rc;
 281
 282        src = ioremap(ctx->src_base + offset, ctx->var2);
 283        if (!src)
 284                return -ENOMEM;
 285        dst = ioremap(ctx->dst_base + offset, ctx->var2);
 286        if (!dst) {
 287                iounmap(src);
 288                return -ENOMEM;
 289        }
 290
 291        memmove(dst, src, ctx->var2);
 292
 293        iounmap(src);
 294        iounmap(dst);
 295
 296        return 0;
 297}
 298
 299static struct apei_exec_ins_type erst_ins_type[] = {
 300        [ACPI_ERST_READ_REGISTER] = {
 301                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 302                .run = apei_exec_read_register,
 303        },
 304        [ACPI_ERST_READ_REGISTER_VALUE] = {
 305                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 306                .run = apei_exec_read_register_value,
 307        },
 308        [ACPI_ERST_WRITE_REGISTER] = {
 309                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 310                .run = apei_exec_write_register,
 311        },
 312        [ACPI_ERST_WRITE_REGISTER_VALUE] = {
 313                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 314                .run = apei_exec_write_register_value,
 315        },
 316        [ACPI_ERST_NOOP] = {
 317                .flags = 0,
 318                .run = apei_exec_noop,
 319        },
 320        [ACPI_ERST_LOAD_VAR1] = {
 321                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 322                .run = erst_exec_load_var1,
 323        },
 324        [ACPI_ERST_LOAD_VAR2] = {
 325                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 326                .run = erst_exec_load_var2,
 327        },
 328        [ACPI_ERST_STORE_VAR1] = {
 329                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 330                .run = erst_exec_store_var1,
 331        },
 332        [ACPI_ERST_ADD] = {
 333                .flags = 0,
 334                .run = erst_exec_add,
 335        },
 336        [ACPI_ERST_SUBTRACT] = {
 337                .flags = 0,
 338                .run = erst_exec_subtract,
 339        },
 340        [ACPI_ERST_ADD_VALUE] = {
 341                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 342                .run = erst_exec_add_value,
 343        },
 344        [ACPI_ERST_SUBTRACT_VALUE] = {
 345                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 346                .run = erst_exec_subtract_value,
 347        },
 348        [ACPI_ERST_STALL] = {
 349                .flags = 0,
 350                .run = erst_exec_stall,
 351        },
 352        [ACPI_ERST_STALL_WHILE_TRUE] = {
 353                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 354                .run = erst_exec_stall_while_true,
 355        },
 356        [ACPI_ERST_SKIP_NEXT_IF_TRUE] = {
 357                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 358                .run = erst_exec_skip_next_instruction_if_true,
 359        },
 360        [ACPI_ERST_GOTO] = {
 361                .flags = 0,
 362                .run = erst_exec_goto,
 363        },
 364        [ACPI_ERST_SET_SRC_ADDRESS_BASE] = {
 365                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 366                .run = erst_exec_set_src_address_base,
 367        },
 368        [ACPI_ERST_SET_DST_ADDRESS_BASE] = {
 369                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 370                .run = erst_exec_set_dst_address_base,
 371        },
 372        [ACPI_ERST_MOVE_DATA] = {
 373                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 374                .run = erst_exec_move_data,
 375        },
 376};
 377
 378static inline void erst_exec_ctx_init(struct apei_exec_context *ctx)
 379{
 380        apei_exec_ctx_init(ctx, erst_ins_type, ARRAY_SIZE(erst_ins_type),
 381                           ERST_TAB_ENTRY(erst_tab), erst_tab->entries);
 382}
 383
 384static int erst_get_erange(struct erst_erange *range)
 385{
 386        struct apei_exec_context ctx;
 387        int rc;
 388
 389        erst_exec_ctx_init(&ctx);
 390        rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_RANGE);
 391        if (rc)
 392                return rc;
 393        range->base = apei_exec_ctx_get_output(&ctx);
 394        rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_LENGTH);
 395        if (rc)
 396                return rc;
 397        range->size = apei_exec_ctx_get_output(&ctx);
 398        rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_ATTRIBUTES);
 399        if (rc)
 400                return rc;
 401        range->attr = apei_exec_ctx_get_output(&ctx);
 402
 403        return 0;
 404}
 405
 406static ssize_t __erst_get_record_count(void)
 407{
 408        struct apei_exec_context ctx;
 409        int rc;
 410
 411        erst_exec_ctx_init(&ctx);
 412        rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_COUNT);
 413        if (rc)
 414                return rc;
 415        return apei_exec_ctx_get_output(&ctx);
 416}
 417
 418ssize_t erst_get_record_count(void)
 419{
 420        ssize_t count;
 421        unsigned long flags;
 422
 423        if (erst_disable)
 424                return -ENODEV;
 425
 426        raw_spin_lock_irqsave(&erst_lock, flags);
 427        count = __erst_get_record_count();
 428        raw_spin_unlock_irqrestore(&erst_lock, flags);
 429
 430        return count;
 431}
 432EXPORT_SYMBOL_GPL(erst_get_record_count);
 433
 434#define ERST_RECORD_ID_CACHE_SIZE_MIN   16
 435#define ERST_RECORD_ID_CACHE_SIZE_MAX   1024
 436
 437struct erst_record_id_cache {
 438        struct mutex lock;
 439        u64 *entries;
 440        int len;
 441        int size;
 442        int refcount;
 443};
 444
 445static struct erst_record_id_cache erst_record_id_cache = {
 446        .lock = __MUTEX_INITIALIZER(erst_record_id_cache.lock),
 447        .refcount = 0,
 448};
 449
 450static int __erst_get_next_record_id(u64 *record_id)
 451{
 452        struct apei_exec_context ctx;
 453        int rc;
 454
 455        erst_exec_ctx_init(&ctx);
 456        rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_ID);
 457        if (rc)
 458                return rc;
 459        *record_id = apei_exec_ctx_get_output(&ctx);
 460
 461        return 0;
 462}
 463
 464int erst_get_record_id_begin(int *pos)
 465{
 466        int rc;
 467
 468        if (erst_disable)
 469                return -ENODEV;
 470
 471        rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
 472        if (rc)
 473                return rc;
 474        erst_record_id_cache.refcount++;
 475        mutex_unlock(&erst_record_id_cache.lock);
 476
 477        *pos = 0;
 478
 479        return 0;
 480}
 481EXPORT_SYMBOL_GPL(erst_get_record_id_begin);
 482
 483/* erst_record_id_cache.lock must be held by caller */
 484static int __erst_record_id_cache_add_one(void)
 485{
 486        u64 id, prev_id, first_id;
 487        int i, rc;
 488        u64 *entries;
 489        unsigned long flags;
 490
 491        id = prev_id = first_id = APEI_ERST_INVALID_RECORD_ID;
 492retry:
 493        raw_spin_lock_irqsave(&erst_lock, flags);
 494        rc = __erst_get_next_record_id(&id);
 495        raw_spin_unlock_irqrestore(&erst_lock, flags);
 496        if (rc == -ENOENT)
 497                return 0;
 498        if (rc)
 499                return rc;
 500        if (id == APEI_ERST_INVALID_RECORD_ID)
 501                return 0;
 502        /* can not skip current ID, or loop back to first ID */
 503        if (id == prev_id || id == first_id)
 504                return 0;
 505        if (first_id == APEI_ERST_INVALID_RECORD_ID)
 506                first_id = id;
 507        prev_id = id;
 508
 509        entries = erst_record_id_cache.entries;
 510        for (i = 0; i < erst_record_id_cache.len; i++) {
 511                if (entries[i] == id)
 512                        break;
 513        }
 514        /* record id already in cache, try next */
 515        if (i < erst_record_id_cache.len)
 516                goto retry;
 517        if (erst_record_id_cache.len >= erst_record_id_cache.size) {
 518                int new_size, alloc_size;
 519                u64 *new_entries;
 520
 521                new_size = erst_record_id_cache.size * 2;
 522                new_size = clamp_val(new_size, ERST_RECORD_ID_CACHE_SIZE_MIN,
 523                                     ERST_RECORD_ID_CACHE_SIZE_MAX);
 524                if (new_size <= erst_record_id_cache.size) {
 525                        if (printk_ratelimit())
 526                                pr_warn(FW_WARN "too many record IDs!\n");
 527                        return 0;
 528                }
 529                alloc_size = new_size * sizeof(entries[0]);
 530                if (alloc_size < PAGE_SIZE)
 531                        new_entries = kmalloc(alloc_size, GFP_KERNEL);
 532                else
 533                        new_entries = vmalloc(alloc_size);
 534                if (!new_entries)
 535                        return -ENOMEM;
 536                memcpy(new_entries, entries,
 537                       erst_record_id_cache.len * sizeof(entries[0]));
 538                if (erst_record_id_cache.size < PAGE_SIZE)
 539                        kfree(entries);
 540                else
 541                        vfree(entries);
 542                erst_record_id_cache.entries = entries = new_entries;
 543                erst_record_id_cache.size = new_size;
 544        }
 545        entries[i] = id;
 546        erst_record_id_cache.len++;
 547
 548        return 1;
 549}
 550
 551/*
 552 * Get the record ID of an existing error record on the persistent
 553 * storage. If there is no error record on the persistent storage, the
 554 * returned record_id is APEI_ERST_INVALID_RECORD_ID.
 555 */
 556int erst_get_record_id_next(int *pos, u64 *record_id)
 557{
 558        int rc = 0;
 559        u64 *entries;
 560
 561        if (erst_disable)
 562                return -ENODEV;
 563
 564        /* must be enclosed by erst_get_record_id_begin/end */
 565        BUG_ON(!erst_record_id_cache.refcount);
 566        BUG_ON(*pos < 0 || *pos > erst_record_id_cache.len);
 567
 568        mutex_lock(&erst_record_id_cache.lock);
 569        entries = erst_record_id_cache.entries;
 570        for (; *pos < erst_record_id_cache.len; (*pos)++)
 571                if (entries[*pos] != APEI_ERST_INVALID_RECORD_ID)
 572                        break;
 573        /* found next record id in cache */
 574        if (*pos < erst_record_id_cache.len) {
 575                *record_id = entries[*pos];
 576                (*pos)++;
 577                goto out_unlock;
 578        }
 579
 580        /* Try to add one more record ID to cache */
 581        rc = __erst_record_id_cache_add_one();
 582        if (rc < 0)
 583                goto out_unlock;
 584        /* successfully add one new ID */
 585        if (rc == 1) {
 586                *record_id = erst_record_id_cache.entries[*pos];
 587                (*pos)++;
 588                rc = 0;
 589        } else {
 590                *pos = -1;
 591                *record_id = APEI_ERST_INVALID_RECORD_ID;
 592        }
 593out_unlock:
 594        mutex_unlock(&erst_record_id_cache.lock);
 595
 596        return rc;
 597}
 598EXPORT_SYMBOL_GPL(erst_get_record_id_next);
 599
 600/* erst_record_id_cache.lock must be held by caller */
 601static void __erst_record_id_cache_compact(void)
 602{
 603        int i, wpos = 0;
 604        u64 *entries;
 605
 606        if (erst_record_id_cache.refcount)
 607                return;
 608
 609        entries = erst_record_id_cache.entries;
 610        for (i = 0; i < erst_record_id_cache.len; i++) {
 611                if (entries[i] == APEI_ERST_INVALID_RECORD_ID)
 612                        continue;
 613                if (wpos != i)
 614                        memcpy(&entries[wpos], &entries[i], sizeof(entries[i]));
 615                wpos++;
 616        }
 617        erst_record_id_cache.len = wpos;
 618}
 619
 620void erst_get_record_id_end(void)
 621{
 622        /*
 623         * erst_disable != 0 should be detected by invoker via the
 624         * return value of erst_get_record_id_begin/next, so this
 625         * function should not be called for erst_disable != 0.
 626         */
 627        BUG_ON(erst_disable);
 628
 629        mutex_lock(&erst_record_id_cache.lock);
 630        erst_record_id_cache.refcount--;
 631        BUG_ON(erst_record_id_cache.refcount < 0);
 632        __erst_record_id_cache_compact();
 633        mutex_unlock(&erst_record_id_cache.lock);
 634}
 635EXPORT_SYMBOL_GPL(erst_get_record_id_end);
 636
 637static int __erst_write_to_storage(u64 offset)
 638{
 639        struct apei_exec_context ctx;
 640        u64 timeout = FIRMWARE_TIMEOUT;
 641        u64 val;
 642        int rc;
 643
 644        erst_exec_ctx_init(&ctx);
 645        rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_WRITE);
 646        if (rc)
 647                return rc;
 648        apei_exec_ctx_set_input(&ctx, offset);
 649        rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_OFFSET);
 650        if (rc)
 651                return rc;
 652        rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
 653        if (rc)
 654                return rc;
 655        for (;;) {
 656                rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
 657                if (rc)
 658                        return rc;
 659                val = apei_exec_ctx_get_output(&ctx);
 660                if (!val)
 661                        break;
 662                if (erst_timedout(&timeout, SPIN_UNIT))
 663                        return -EIO;
 664        }
 665        rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
 666        if (rc)
 667                return rc;
 668        val = apei_exec_ctx_get_output(&ctx);
 669        rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
 670        if (rc)
 671                return rc;
 672
 673        return erst_errno(val);
 674}
 675
 676static int __erst_read_from_storage(u64 record_id, u64 offset)
 677{
 678        struct apei_exec_context ctx;
 679        u64 timeout = FIRMWARE_TIMEOUT;
 680        u64 val;
 681        int rc;
 682
 683        erst_exec_ctx_init(&ctx);
 684        rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_READ);
 685        if (rc)
 686                return rc;
 687        apei_exec_ctx_set_input(&ctx, offset);
 688        rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_OFFSET);
 689        if (rc)
 690                return rc;
 691        apei_exec_ctx_set_input(&ctx, record_id);
 692        rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_ID);
 693        if (rc)
 694                return rc;
 695        rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
 696        if (rc)
 697                return rc;
 698        for (;;) {
 699                rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
 700                if (rc)
 701                        return rc;
 702                val = apei_exec_ctx_get_output(&ctx);
 703                if (!val)
 704                        break;
 705                if (erst_timedout(&timeout, SPIN_UNIT))
 706                        return -EIO;
 707        };
 708        rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
 709        if (rc)
 710                return rc;
 711        val = apei_exec_ctx_get_output(&ctx);
 712        rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
 713        if (rc)
 714                return rc;
 715
 716        return erst_errno(val);
 717}
 718
 719static int __erst_clear_from_storage(u64 record_id)
 720{
 721        struct apei_exec_context ctx;
 722        u64 timeout = FIRMWARE_TIMEOUT;
 723        u64 val;
 724        int rc;
 725
 726        erst_exec_ctx_init(&ctx);
 727        rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_CLEAR);
 728        if (rc)
 729                return rc;
 730        apei_exec_ctx_set_input(&ctx, record_id);
 731        rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_ID);
 732        if (rc)
 733                return rc;
 734        rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
 735        if (rc)
 736                return rc;
 737        for (;;) {
 738                rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
 739                if (rc)
 740                        return rc;
 741                val = apei_exec_ctx_get_output(&ctx);
 742                if (!val)
 743                        break;
 744                if (erst_timedout(&timeout, SPIN_UNIT))
 745                        return -EIO;
 746        }
 747        rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
 748        if (rc)
 749                return rc;
 750        val = apei_exec_ctx_get_output(&ctx);
 751        rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
 752        if (rc)
 753                return rc;
 754
 755        return erst_errno(val);
 756}
 757
 758/* NVRAM ERST Error Log Address Range is not supported yet */
 759static void pr_unimpl_nvram(void)
 760{
 761        if (printk_ratelimit())
 762                pr_warn("NVRAM ERST Log Address Range not implemented yet.\n");
 763}
 764
 765static int __erst_write_to_nvram(const struct cper_record_header *record)
 766{
 767        /* do not print message, because printk is not safe for NMI */
 768        return -ENOSYS;
 769}
 770
 771static int __erst_read_to_erange_from_nvram(u64 record_id, u64 *offset)
 772{
 773        pr_unimpl_nvram();
 774        return -ENOSYS;
 775}
 776
 777static int __erst_clear_from_nvram(u64 record_id)
 778{
 779        pr_unimpl_nvram();
 780        return -ENOSYS;
 781}
 782
 783int erst_write(const struct cper_record_header *record)
 784{
 785        int rc;
 786        unsigned long flags;
 787        struct cper_record_header *rcd_erange;
 788
 789        if (erst_disable)
 790                return -ENODEV;
 791
 792        if (memcmp(record->signature, CPER_SIG_RECORD, CPER_SIG_SIZE))
 793                return -EINVAL;
 794
 795        if (erst_erange.attr & ERST_RANGE_NVRAM) {
 796                if (!raw_spin_trylock_irqsave(&erst_lock, flags))
 797                        return -EBUSY;
 798                rc = __erst_write_to_nvram(record);
 799                raw_spin_unlock_irqrestore(&erst_lock, flags);
 800                return rc;
 801        }
 802
 803        if (record->record_length > erst_erange.size)
 804                return -EINVAL;
 805
 806        if (!raw_spin_trylock_irqsave(&erst_lock, flags))
 807                return -EBUSY;
 808        memcpy(erst_erange.vaddr, record, record->record_length);
 809        rcd_erange = erst_erange.vaddr;
 810        /* signature for serialization system */
 811        memcpy(&rcd_erange->persistence_information, "ER", 2);
 812
 813        rc = __erst_write_to_storage(0);
 814        raw_spin_unlock_irqrestore(&erst_lock, flags);
 815
 816        return rc;
 817}
 818EXPORT_SYMBOL_GPL(erst_write);
 819
 820static int __erst_read_to_erange(u64 record_id, u64 *offset)
 821{
 822        int rc;
 823
 824        if (erst_erange.attr & ERST_RANGE_NVRAM)
 825                return __erst_read_to_erange_from_nvram(
 826                        record_id, offset);
 827
 828        rc = __erst_read_from_storage(record_id, 0);
 829        if (rc)
 830                return rc;
 831        *offset = 0;
 832
 833        return 0;
 834}
 835
 836static ssize_t __erst_read(u64 record_id, struct cper_record_header *record,
 837                           size_t buflen)
 838{
 839        int rc;
 840        u64 offset, len = 0;
 841        struct cper_record_header *rcd_tmp;
 842
 843        rc = __erst_read_to_erange(record_id, &offset);
 844        if (rc)
 845                return rc;
 846        rcd_tmp = erst_erange.vaddr + offset;
 847        len = rcd_tmp->record_length;
 848        if (len <= buflen)
 849                memcpy(record, rcd_tmp, len);
 850
 851        return len;
 852}
 853
 854/*
 855 * If return value > buflen, the buffer size is not big enough,
 856 * else if return value < 0, something goes wrong,
 857 * else everything is OK, and return value is record length
 858 */
 859ssize_t erst_read(u64 record_id, struct cper_record_header *record,
 860                  size_t buflen)
 861{
 862        ssize_t len;
 863        unsigned long flags;
 864
 865        if (erst_disable)
 866                return -ENODEV;
 867
 868        raw_spin_lock_irqsave(&erst_lock, flags);
 869        len = __erst_read(record_id, record, buflen);
 870        raw_spin_unlock_irqrestore(&erst_lock, flags);
 871        return len;
 872}
 873EXPORT_SYMBOL_GPL(erst_read);
 874
 875int erst_clear(u64 record_id)
 876{
 877        int rc, i;
 878        unsigned long flags;
 879        u64 *entries;
 880
 881        if (erst_disable)
 882                return -ENODEV;
 883
 884        rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
 885        if (rc)
 886                return rc;
 887        raw_spin_lock_irqsave(&erst_lock, flags);
 888        if (erst_erange.attr & ERST_RANGE_NVRAM)
 889                rc = __erst_clear_from_nvram(record_id);
 890        else
 891                rc = __erst_clear_from_storage(record_id);
 892        raw_spin_unlock_irqrestore(&erst_lock, flags);
 893        if (rc)
 894                goto out;
 895        entries = erst_record_id_cache.entries;
 896        for (i = 0; i < erst_record_id_cache.len; i++) {
 897                if (entries[i] == record_id)
 898                        entries[i] = APEI_ERST_INVALID_RECORD_ID;
 899        }
 900        __erst_record_id_cache_compact();
 901out:
 902        mutex_unlock(&erst_record_id_cache.lock);
 903        return rc;
 904}
 905EXPORT_SYMBOL_GPL(erst_clear);
 906
 907static int __init setup_erst_disable(char *str)
 908{
 909        erst_disable = 1;
 910        return 0;
 911}
 912
 913__setup("erst_disable", setup_erst_disable);
 914
 915static int erst_check_table(struct acpi_table_erst *erst_tab)
 916{
 917        if ((erst_tab->header_length !=
 918             (sizeof(struct acpi_table_erst) - sizeof(erst_tab->header)))
 919            && (erst_tab->header_length != sizeof(struct acpi_table_erst)))
 920                return -EINVAL;
 921        if (erst_tab->header.length < sizeof(struct acpi_table_erst))
 922                return -EINVAL;
 923        if (erst_tab->entries !=
 924            (erst_tab->header.length - sizeof(struct acpi_table_erst)) /
 925            sizeof(struct acpi_erst_entry))
 926                return -EINVAL;
 927
 928        return 0;
 929}
 930
 931static int erst_open_pstore(struct pstore_info *psi);
 932static int erst_close_pstore(struct pstore_info *psi);
 933static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
 934                           struct timespec *time, char **buf,
 935                           bool *compressed, struct pstore_info *psi);
 936static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
 937                       u64 *id, unsigned int part, int count, bool compressed,
 938                       size_t size, struct pstore_info *psi);
 939static int erst_clearer(enum pstore_type_id type, u64 id, int count,
 940                        struct timespec time, struct pstore_info *psi);
 941
 942static struct pstore_info erst_info = {
 943        .owner          = THIS_MODULE,
 944        .name           = "erst",
 945        .open           = erst_open_pstore,
 946        .close          = erst_close_pstore,
 947        .read           = erst_reader,
 948        .write          = erst_writer,
 949        .erase          = erst_clearer
 950};
 951
 952#define CPER_CREATOR_PSTORE                                             \
 953        UUID_LE(0x75a574e3, 0x5052, 0x4b29, 0x8a, 0x8e, 0xbe, 0x2c,     \
 954                0x64, 0x90, 0xb8, 0x9d)
 955#define CPER_SECTION_TYPE_DMESG                                         \
 956        UUID_LE(0xc197e04e, 0xd545, 0x4a70, 0x9c, 0x17, 0xa5, 0x54,     \
 957                0x94, 0x19, 0xeb, 0x12)
 958#define CPER_SECTION_TYPE_DMESG_Z                                       \
 959        UUID_LE(0x4f118707, 0x04dd, 0x4055, 0xb5, 0xdd, 0x95, 0x6d,     \
 960                0x34, 0xdd, 0xfa, 0xc6)
 961#define CPER_SECTION_TYPE_MCE                                           \
 962        UUID_LE(0xfe08ffbe, 0x95e4, 0x4be7, 0xbc, 0x73, 0x40, 0x96,     \
 963                0x04, 0x4a, 0x38, 0xfc)
 964
 965struct cper_pstore_record {
 966        struct cper_record_header hdr;
 967        struct cper_section_descriptor sec_hdr;
 968        char data[];
 969} __packed;
 970
 971static int reader_pos;
 972
 973static int erst_open_pstore(struct pstore_info *psi)
 974{
 975        int rc;
 976
 977        if (erst_disable)
 978                return -ENODEV;
 979
 980        rc = erst_get_record_id_begin(&reader_pos);
 981
 982        return rc;
 983}
 984
 985static int erst_close_pstore(struct pstore_info *psi)
 986{
 987        erst_get_record_id_end();
 988
 989        return 0;
 990}
 991
 992static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
 993                           struct timespec *time, char **buf,
 994                           bool *compressed, struct pstore_info *psi)
 995{
 996        int rc;
 997        ssize_t len = 0;
 998        u64 record_id;
 999        struct cper_pstore_record *rcd;
1000        size_t rcd_len = sizeof(*rcd) + erst_info.bufsize;
1001
1002        if (erst_disable)
1003                return -ENODEV;
1004
1005        rcd = kmalloc(rcd_len, GFP_KERNEL);
1006        if (!rcd) {
1007                rc = -ENOMEM;
1008                goto out;
1009        }
1010skip:
1011        rc = erst_get_record_id_next(&reader_pos, &record_id);
1012        if (rc)
1013                goto out;
1014
1015        /* no more record */
1016        if (record_id == APEI_ERST_INVALID_RECORD_ID) {
1017                rc = -EINVAL;
1018                goto out;
1019        }
1020
1021        len = erst_read(record_id, &rcd->hdr, rcd_len);
1022        /* The record may be cleared by others, try read next record */
1023        if (len == -ENOENT)
1024                goto skip;
1025        else if (len < sizeof(*rcd)) {
1026                rc = -EIO;
1027                goto out;
1028        }
1029        if (uuid_le_cmp(rcd->hdr.creator_id, CPER_CREATOR_PSTORE) != 0)
1030                goto skip;
1031
1032        *buf = kmalloc(len, GFP_KERNEL);
1033        if (*buf == NULL) {
1034                rc = -ENOMEM;
1035                goto out;
1036        }
1037        memcpy(*buf, rcd->data, len - sizeof(*rcd));
1038        *id = record_id;
1039        *compressed = false;
1040        if (uuid_le_cmp(rcd->sec_hdr.section_type,
1041                        CPER_SECTION_TYPE_DMESG_Z) == 0) {
1042                *type = PSTORE_TYPE_DMESG;
1043                *compressed = true;
1044        } else if (uuid_le_cmp(rcd->sec_hdr.section_type,
1045                        CPER_SECTION_TYPE_DMESG) == 0)
1046                *type = PSTORE_TYPE_DMESG;
1047        else if (uuid_le_cmp(rcd->sec_hdr.section_type,
1048                             CPER_SECTION_TYPE_MCE) == 0)
1049                *type = PSTORE_TYPE_MCE;
1050        else
1051                *type = PSTORE_TYPE_UNKNOWN;
1052
1053        if (rcd->hdr.validation_bits & CPER_VALID_TIMESTAMP)
1054                time->tv_sec = rcd->hdr.timestamp;
1055        else
1056                time->tv_sec = 0;
1057        time->tv_nsec = 0;
1058
1059out:
1060        kfree(rcd);
1061        return (rc < 0) ? rc : (len - sizeof(*rcd));
1062}
1063
1064static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
1065                       u64 *id, unsigned int part, int count, bool compressed,
1066                       size_t size, struct pstore_info *psi)
1067{
1068        struct cper_pstore_record *rcd = (struct cper_pstore_record *)
1069                                        (erst_info.buf - sizeof(*rcd));
1070        int ret;
1071
1072        memset(rcd, 0, sizeof(*rcd));
1073        memcpy(rcd->hdr.signature, CPER_SIG_RECORD, CPER_SIG_SIZE);
1074        rcd->hdr.revision = CPER_RECORD_REV;
1075        rcd->hdr.signature_end = CPER_SIG_END;
1076        rcd->hdr.section_count = 1;
1077        rcd->hdr.error_severity = CPER_SEV_FATAL;
1078        /* timestamp valid. platform_id, partition_id are invalid */
1079        rcd->hdr.validation_bits = CPER_VALID_TIMESTAMP;
1080        rcd->hdr.timestamp = get_seconds();
1081        rcd->hdr.record_length = sizeof(*rcd) + size;
1082        rcd->hdr.creator_id = CPER_CREATOR_PSTORE;
1083        rcd->hdr.notification_type = CPER_NOTIFY_MCE;
1084        rcd->hdr.record_id = cper_next_record_id();
1085        rcd->hdr.flags = CPER_HW_ERROR_FLAGS_PREVERR;
1086
1087        rcd->sec_hdr.section_offset = sizeof(*rcd);
1088        rcd->sec_hdr.section_length = size;
1089        rcd->sec_hdr.revision = CPER_SEC_REV;
1090        /* fru_id and fru_text is invalid */
1091        rcd->sec_hdr.validation_bits = 0;
1092        rcd->sec_hdr.flags = CPER_SEC_PRIMARY;
1093        switch (type) {
1094        case PSTORE_TYPE_DMESG:
1095                if (compressed)
1096                        rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG_Z;
1097                else
1098                        rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG;
1099                break;
1100        case PSTORE_TYPE_MCE:
1101                rcd->sec_hdr.section_type = CPER_SECTION_TYPE_MCE;
1102                break;
1103        default:
1104                return -EINVAL;
1105        }
1106        rcd->sec_hdr.section_severity = CPER_SEV_FATAL;
1107
1108        ret = erst_write(&rcd->hdr);
1109        *id = rcd->hdr.record_id;
1110
1111        return ret;
1112}
1113
1114static int erst_clearer(enum pstore_type_id type, u64 id, int count,
1115                        struct timespec time, struct pstore_info *psi)
1116{
1117        return erst_clear(id);
1118}
1119
1120static int __init erst_init(void)
1121{
1122        int rc = 0;
1123        acpi_status status;
1124        struct apei_exec_context ctx;
1125        struct apei_resources erst_resources;
1126        struct resource *r;
1127        char *buf;
1128
1129        if (acpi_disabled)
1130                goto err;
1131
1132        if (erst_disable) {
1133                pr_info(
1134        "Error Record Serialization Table (ERST) support is disabled.\n");
1135                goto err;
1136        }
1137
1138        status = acpi_get_table(ACPI_SIG_ERST, 0,
1139                                (struct acpi_table_header **)&erst_tab);
1140        if (status == AE_NOT_FOUND)
1141                goto err;
1142        else if (ACPI_FAILURE(status)) {
1143                const char *msg = acpi_format_exception(status);
1144                pr_err("Failed to get table, %s\n", msg);
1145                rc = -EINVAL;
1146                goto err;
1147        }
1148
1149        rc = erst_check_table(erst_tab);
1150        if (rc) {
1151                pr_err(FW_BUG "ERST table is invalid.\n");
1152                goto err;
1153        }
1154
1155        apei_resources_init(&erst_resources);
1156        erst_exec_ctx_init(&ctx);
1157        rc = apei_exec_collect_resources(&ctx, &erst_resources);
1158        if (rc)
1159                goto err_fini;
1160        rc = apei_resources_request(&erst_resources, "APEI ERST");
1161        if (rc)
1162                goto err_fini;
1163        rc = apei_exec_pre_map_gars(&ctx);
1164        if (rc)
1165                goto err_release;
1166        rc = erst_get_erange(&erst_erange);
1167        if (rc) {
1168                if (rc == -ENODEV)
1169                        pr_info(
1170        "The corresponding hardware device or firmware implementation "
1171        "is not available.\n");
1172                else
1173                        pr_err("Failed to get Error Log Address Range.\n");
1174                goto err_unmap_reg;
1175        }
1176
1177        r = request_mem_region(erst_erange.base, erst_erange.size, "APEI ERST");
1178        if (!r) {
1179                pr_err("Can not request [mem %#010llx-%#010llx] for ERST.\n",
1180                       (unsigned long long)erst_erange.base,
1181                       (unsigned long long)erst_erange.base + erst_erange.size - 1);
1182                rc = -EIO;
1183                goto err_unmap_reg;
1184        }
1185        rc = -ENOMEM;
1186        erst_erange.vaddr = ioremap_cache(erst_erange.base,
1187                                          erst_erange.size);
1188        if (!erst_erange.vaddr)
1189                goto err_release_erange;
1190
1191        pr_info(
1192        "Error Record Serialization Table (ERST) support is initialized.\n");
1193
1194        buf = kmalloc(erst_erange.size, GFP_KERNEL);
1195        spin_lock_init(&erst_info.buf_lock);
1196        if (buf) {
1197                erst_info.buf = buf + sizeof(struct cper_pstore_record);
1198                erst_info.bufsize = erst_erange.size -
1199                                    sizeof(struct cper_pstore_record);
1200                rc = pstore_register(&erst_info);
1201                if (rc) {
1202                        if (rc != -EPERM)
1203                                pr_info(
1204                                "Could not register with persistent store.\n");
1205                        erst_info.buf = NULL;
1206                        erst_info.bufsize = 0;
1207                        kfree(buf);
1208                }
1209        } else
1210                pr_err(
1211                "Failed to allocate %lld bytes for persistent store error log.\n",
1212                erst_erange.size);
1213
1214        return 0;
1215
1216err_release_erange:
1217        release_mem_region(erst_erange.base, erst_erange.size);
1218err_unmap_reg:
1219        apei_exec_post_unmap_gars(&ctx);
1220err_release:
1221        apei_resources_release(&erst_resources);
1222err_fini:
1223        apei_resources_fini(&erst_resources);
1224err:
1225        erst_disable = 1;
1226        return rc;
1227}
1228
1229device_initcall(erst_init);
1230