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#define ERST_PFX "ERST: "
  43
  44/* ERST command status */
  45#define ERST_STATUS_SUCCESS                     0x0
  46#define ERST_STATUS_NOT_ENOUGH_SPACE            0x1
  47#define ERST_STATUS_HARDWARE_NOT_AVAILABLE      0x2
  48#define ERST_STATUS_FAILED                      0x3
  49#define ERST_STATUS_RECORD_STORE_EMPTY          0x4
  50#define ERST_STATUS_RECORD_NOT_FOUND            0x5
  51
  52#define ERST_TAB_ENTRY(tab)                                             \
  53        ((struct acpi_whea_header *)((char *)(tab) +                    \
  54                                     sizeof(struct acpi_table_erst)))
  55
  56#define SPIN_UNIT               100                     /* 100ns */
  57/* Firmware should respond within 1 milliseconds */
  58#define FIRMWARE_TIMEOUT        (1 * NSEC_PER_MSEC)
  59#define FIRMWARE_MAX_STALL      50                      /* 50us */
  60
  61int erst_disable;
  62EXPORT_SYMBOL_GPL(erst_disable);
  63
  64static struct acpi_table_erst *erst_tab;
  65
  66/* ERST Error Log Address Range atrributes */
  67#define ERST_RANGE_RESERVED     0x0001
  68#define ERST_RANGE_NVRAM        0x0002
  69#define ERST_RANGE_SLOW         0x0004
  70
  71/*
  72 * ERST Error Log Address Range, used as buffer for reading/writing
  73 * error records.
  74 */
  75static struct erst_erange {
  76        u64 base;
  77        u64 size;
  78        void __iomem *vaddr;
  79        u32 attr;
  80} erst_erange;
  81
  82/*
  83 * Prevent ERST interpreter to run simultaneously, because the
  84 * corresponding firmware implementation may not work properly when
  85 * invoked simultaneously.
  86 *
  87 * It is used to provide exclusive accessing for ERST Error Log
  88 * Address Range too.
  89 */
  90static DEFINE_RAW_SPINLOCK(erst_lock);
  91
  92static inline int erst_errno(int command_status)
  93{
  94        switch (command_status) {
  95        case ERST_STATUS_SUCCESS:
  96                return 0;
  97        case ERST_STATUS_HARDWARE_NOT_AVAILABLE:
  98                return -ENODEV;
  99        case ERST_STATUS_NOT_ENOUGH_SPACE:
 100                return -ENOSPC;
 101        case ERST_STATUS_RECORD_STORE_EMPTY:
 102        case ERST_STATUS_RECORD_NOT_FOUND:
 103                return -ENOENT;
 104        default:
 105                return -EINVAL;
 106        }
 107}
 108
 109static int erst_timedout(u64 *t, u64 spin_unit)
 110{
 111        if ((s64)*t < spin_unit) {
 112                pr_warning(FW_WARN ERST_PFX
 113                           "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_warning(FW_WARN ERST_PFX
 190                        "Too long stall time for stall instruction: %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_warning(FW_WARN ERST_PFX
 210                "Too long stall time for stall while true instruction: %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_warning(ERST_PFX
 275                           "MOVE_DATA can not be used in interrupt context");
 276                return -EBUSY;
 277        }
 278
 279        rc = __apei_exec_read_register(entry, &offset);
 280        if (rc)
 281                return rc;
 282
 283        src = ioremap(ctx->src_base + offset, ctx->var2);
 284        if (!src)
 285                return -ENOMEM;
 286        dst = ioremap(ctx->dst_base + offset, ctx->var2);
 287        if (!dst)
 288                return -ENOMEM;
 289
 290        memmove(dst, src, ctx->var2);
 291
 292        iounmap(src);
 293        iounmap(dst);
 294
 295        return 0;
 296}
 297
 298static struct apei_exec_ins_type erst_ins_type[] = {
 299        [ACPI_ERST_READ_REGISTER] = {
 300                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 301                .run = apei_exec_read_register,
 302        },
 303        [ACPI_ERST_READ_REGISTER_VALUE] = {
 304                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 305                .run = apei_exec_read_register_value,
 306        },
 307        [ACPI_ERST_WRITE_REGISTER] = {
 308                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 309                .run = apei_exec_write_register,
 310        },
 311        [ACPI_ERST_WRITE_REGISTER_VALUE] = {
 312                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 313                .run = apei_exec_write_register_value,
 314        },
 315        [ACPI_ERST_NOOP] = {
 316                .flags = 0,
 317                .run = apei_exec_noop,
 318        },
 319        [ACPI_ERST_LOAD_VAR1] = {
 320                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 321                .run = erst_exec_load_var1,
 322        },
 323        [ACPI_ERST_LOAD_VAR2] = {
 324                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 325                .run = erst_exec_load_var2,
 326        },
 327        [ACPI_ERST_STORE_VAR1] = {
 328                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 329                .run = erst_exec_store_var1,
 330        },
 331        [ACPI_ERST_ADD] = {
 332                .flags = 0,
 333                .run = erst_exec_add,
 334        },
 335        [ACPI_ERST_SUBTRACT] = {
 336                .flags = 0,
 337                .run = erst_exec_subtract,
 338        },
 339        [ACPI_ERST_ADD_VALUE] = {
 340                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 341                .run = erst_exec_add_value,
 342        },
 343        [ACPI_ERST_SUBTRACT_VALUE] = {
 344                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 345                .run = erst_exec_subtract_value,
 346        },
 347        [ACPI_ERST_STALL] = {
 348                .flags = 0,
 349                .run = erst_exec_stall,
 350        },
 351        [ACPI_ERST_STALL_WHILE_TRUE] = {
 352                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 353                .run = erst_exec_stall_while_true,
 354        },
 355        [ACPI_ERST_SKIP_NEXT_IF_TRUE] = {
 356                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 357                .run = erst_exec_skip_next_instruction_if_true,
 358        },
 359        [ACPI_ERST_GOTO] = {
 360                .flags = 0,
 361                .run = erst_exec_goto,
 362        },
 363        [ACPI_ERST_SET_SRC_ADDRESS_BASE] = {
 364                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 365                .run = erst_exec_set_src_address_base,
 366        },
 367        [ACPI_ERST_SET_DST_ADDRESS_BASE] = {
 368                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 369                .run = erst_exec_set_dst_address_base,
 370        },
 371        [ACPI_ERST_MOVE_DATA] = {
 372                .flags = APEI_EXEC_INS_ACCESS_REGISTER,
 373                .run = erst_exec_move_data,
 374        },
 375};
 376
 377static inline void erst_exec_ctx_init(struct apei_exec_context *ctx)
 378{
 379        apei_exec_ctx_init(ctx, erst_ins_type, ARRAY_SIZE(erst_ins_type),
 380                           ERST_TAB_ENTRY(erst_tab), erst_tab->entries);
 381}
 382
 383static int erst_get_erange(struct erst_erange *range)
 384{
 385        struct apei_exec_context ctx;
 386        int rc;
 387
 388        erst_exec_ctx_init(&ctx);
 389        rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_RANGE);
 390        if (rc)
 391                return rc;
 392        range->base = apei_exec_ctx_get_output(&ctx);
 393        rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_LENGTH);
 394        if (rc)
 395                return rc;
 396        range->size = apei_exec_ctx_get_output(&ctx);
 397        rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_ATTRIBUTES);
 398        if (rc)
 399                return rc;
 400        range->attr = apei_exec_ctx_get_output(&ctx);
 401
 402        return 0;
 403}
 404
 405static ssize_t __erst_get_record_count(void)
 406{
 407        struct apei_exec_context ctx;
 408        int rc;
 409
 410        erst_exec_ctx_init(&ctx);
 411        rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_COUNT);
 412        if (rc)
 413                return rc;
 414        return apei_exec_ctx_get_output(&ctx);
 415}
 416
 417ssize_t erst_get_record_count(void)
 418{
 419        ssize_t count;
 420        unsigned long flags;
 421
 422        if (erst_disable)
 423                return -ENODEV;
 424
 425        raw_spin_lock_irqsave(&erst_lock, flags);
 426        count = __erst_get_record_count();
 427        raw_spin_unlock_irqrestore(&erst_lock, flags);
 428
 429        return count;
 430}
 431EXPORT_SYMBOL_GPL(erst_get_record_count);
 432
 433#define ERST_RECORD_ID_CACHE_SIZE_MIN   16
 434#define ERST_RECORD_ID_CACHE_SIZE_MAX   1024
 435
 436struct erst_record_id_cache {
 437        struct mutex lock;
 438        u64 *entries;
 439        int len;
 440        int size;
 441        int refcount;
 442};
 443
 444static struct erst_record_id_cache erst_record_id_cache = {
 445        .lock = __MUTEX_INITIALIZER(erst_record_id_cache.lock),
 446        .refcount = 0,
 447};
 448
 449static int __erst_get_next_record_id(u64 *record_id)
 450{
 451        struct apei_exec_context ctx;
 452        int rc;
 453
 454        erst_exec_ctx_init(&ctx);
 455        rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_ID);
 456        if (rc)
 457                return rc;
 458        *record_id = apei_exec_ctx_get_output(&ctx);
 459
 460        return 0;
 461}
 462
 463int erst_get_record_id_begin(int *pos)
 464{
 465        int rc;
 466
 467        if (erst_disable)
 468                return -ENODEV;
 469
 470        rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
 471        if (rc)
 472                return rc;
 473        erst_record_id_cache.refcount++;
 474        mutex_unlock(&erst_record_id_cache.lock);
 475
 476        *pos = 0;
 477
 478        return 0;
 479}
 480EXPORT_SYMBOL_GPL(erst_get_record_id_begin);
 481
 482/* erst_record_id_cache.lock must be held by caller */
 483static int __erst_record_id_cache_add_one(void)
 484{
 485        u64 id, prev_id, first_id;
 486        int i, rc;
 487        u64 *entries;
 488        unsigned long flags;
 489
 490        id = prev_id = first_id = APEI_ERST_INVALID_RECORD_ID;
 491retry:
 492        raw_spin_lock_irqsave(&erst_lock, flags);
 493        rc = __erst_get_next_record_id(&id);
 494        raw_spin_unlock_irqrestore(&erst_lock, flags);
 495        if (rc == -ENOENT)
 496                return 0;
 497        if (rc)
 498                return rc;
 499        if (id == APEI_ERST_INVALID_RECORD_ID)
 500                return 0;
 501        /* can not skip current ID, or loop back to first ID */
 502        if (id == prev_id || id == first_id)
 503                return 0;
 504        if (first_id == APEI_ERST_INVALID_RECORD_ID)
 505                first_id = id;
 506        prev_id = id;
 507
 508        entries = erst_record_id_cache.entries;
 509        for (i = 0; i < erst_record_id_cache.len; i++) {
 510                if (entries[i] == id)
 511                        break;
 512        }
 513        /* record id already in cache, try next */
 514        if (i < erst_record_id_cache.len)
 515                goto retry;
 516        if (erst_record_id_cache.len >= erst_record_id_cache.size) {
 517                int new_size, alloc_size;
 518                u64 *new_entries;
 519
 520                new_size = erst_record_id_cache.size * 2;
 521                new_size = clamp_val(new_size, ERST_RECORD_ID_CACHE_SIZE_MIN,
 522                                     ERST_RECORD_ID_CACHE_SIZE_MAX);
 523                if (new_size <= erst_record_id_cache.size) {
 524                        if (printk_ratelimit())
 525                                pr_warning(FW_WARN ERST_PFX
 526                                           "too many record ID!\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_warning(ERST_PFX
 763                "NVRAM ERST Log Address Range is not implemented yet\n");
 764}
 765
 766static int __erst_write_to_nvram(const struct cper_record_header *record)
 767{
 768        /* do not print message, because printk is not safe for NMI */
 769        return -ENOSYS;
 770}
 771
 772static int __erst_read_to_erange_from_nvram(u64 record_id, u64 *offset)
 773{
 774        pr_unimpl_nvram();
 775        return -ENOSYS;
 776}
 777
 778static int __erst_clear_from_nvram(u64 record_id)
 779{
 780        pr_unimpl_nvram();
 781        return -ENOSYS;
 782}
 783
 784int erst_write(const struct cper_record_header *record)
 785{
 786        int rc;
 787        unsigned long flags;
 788        struct cper_record_header *rcd_erange;
 789
 790        if (erst_disable)
 791                return -ENODEV;
 792
 793        if (memcmp(record->signature, CPER_SIG_RECORD, CPER_SIG_SIZE))
 794                return -EINVAL;
 795
 796        if (erst_erange.attr & ERST_RANGE_NVRAM) {
 797                if (!raw_spin_trylock_irqsave(&erst_lock, flags))
 798                        return -EBUSY;
 799                rc = __erst_write_to_nvram(record);
 800                raw_spin_unlock_irqrestore(&erst_lock, flags);
 801                return rc;
 802        }
 803
 804        if (record->record_length > erst_erange.size)
 805                return -EINVAL;
 806
 807        if (!raw_spin_trylock_irqsave(&erst_lock, flags))
 808                return -EBUSY;
 809        memcpy(erst_erange.vaddr, record, record->record_length);
 810        rcd_erange = erst_erange.vaddr;
 811        /* signature for serialization system */
 812        memcpy(&rcd_erange->persistence_information, "ER", 2);
 813
 814        rc = __erst_write_to_storage(0);
 815        raw_spin_unlock_irqrestore(&erst_lock, flags);
 816
 817        return rc;
 818}
 819EXPORT_SYMBOL_GPL(erst_write);
 820
 821static int __erst_read_to_erange(u64 record_id, u64 *offset)
 822{
 823        int rc;
 824
 825        if (erst_erange.attr & ERST_RANGE_NVRAM)
 826                return __erst_read_to_erange_from_nvram(
 827                        record_id, offset);
 828
 829        rc = __erst_read_from_storage(record_id, 0);
 830        if (rc)
 831                return rc;
 832        *offset = 0;
 833
 834        return 0;
 835}
 836
 837static ssize_t __erst_read(u64 record_id, struct cper_record_header *record,
 838                           size_t buflen)
 839{
 840        int rc;
 841        u64 offset, len = 0;
 842        struct cper_record_header *rcd_tmp;
 843
 844        rc = __erst_read_to_erange(record_id, &offset);
 845        if (rc)
 846                return rc;
 847        rcd_tmp = erst_erange.vaddr + offset;
 848        len = rcd_tmp->record_length;
 849        if (len <= buflen)
 850                memcpy(record, rcd_tmp, len);
 851
 852        return len;
 853}
 854
 855/*
 856 * If return value > buflen, the buffer size is not big enough,
 857 * else if return value < 0, something goes wrong,
 858 * else everything is OK, and return value is record length
 859 */
 860ssize_t erst_read(u64 record_id, struct cper_record_header *record,
 861                  size_t buflen)
 862{
 863        ssize_t len;
 864        unsigned long flags;
 865
 866        if (erst_disable)
 867                return -ENODEV;
 868
 869        raw_spin_lock_irqsave(&erst_lock, flags);
 870        len = __erst_read(record_id, record, buflen);
 871        raw_spin_unlock_irqrestore(&erst_lock, flags);
 872        return len;
 873}
 874EXPORT_SYMBOL_GPL(erst_read);
 875
 876int erst_clear(u64 record_id)
 877{
 878        int rc, i;
 879        unsigned long flags;
 880        u64 *entries;
 881
 882        if (erst_disable)
 883                return -ENODEV;
 884
 885        rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
 886        if (rc)
 887                return rc;
 888        raw_spin_lock_irqsave(&erst_lock, flags);
 889        if (erst_erange.attr & ERST_RANGE_NVRAM)
 890                rc = __erst_clear_from_nvram(record_id);
 891        else
 892                rc = __erst_clear_from_storage(record_id);
 893        raw_spin_unlock_irqrestore(&erst_lock, flags);
 894        if (rc)
 895                goto out;
 896        entries = erst_record_id_cache.entries;
 897        for (i = 0; i < erst_record_id_cache.len; i++) {
 898                if (entries[i] == record_id)
 899                        entries[i] = APEI_ERST_INVALID_RECORD_ID;
 900        }
 901        __erst_record_id_cache_compact();
 902out:
 903        mutex_unlock(&erst_record_id_cache.lock);
 904        return rc;
 905}
 906EXPORT_SYMBOL_GPL(erst_clear);
 907
 908static int __init setup_erst_disable(char *str)
 909{
 910        erst_disable = 1;
 911        return 0;
 912}
 913
 914__setup("erst_disable", setup_erst_disable);
 915
 916static int erst_check_table(struct acpi_table_erst *erst_tab)
 917{
 918        if ((erst_tab->header_length !=
 919             (sizeof(struct acpi_table_erst) - sizeof(erst_tab->header)))
 920            && (erst_tab->header_length != sizeof(struct acpi_table_erst)))
 921                return -EINVAL;
 922        if (erst_tab->header.length < sizeof(struct acpi_table_erst))
 923                return -EINVAL;
 924        if (erst_tab->entries !=
 925            (erst_tab->header.length - sizeof(struct acpi_table_erst)) /
 926            sizeof(struct acpi_erst_entry))
 927                return -EINVAL;
 928
 929        return 0;
 930}
 931
 932static int erst_open_pstore(struct pstore_info *psi);
 933static int erst_close_pstore(struct pstore_info *psi);
 934static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
 935                           struct timespec *time, char **buf,
 936                           struct pstore_info *psi);
 937static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
 938                       u64 *id, unsigned int part, int count,
 939                       size_t size, struct pstore_info *psi);
 940static int erst_clearer(enum pstore_type_id type, u64 id, int count,
 941                        struct timespec time, struct pstore_info *psi);
 942
 943static struct pstore_info erst_info = {
 944        .owner          = THIS_MODULE,
 945        .name           = "erst",
 946        .open           = erst_open_pstore,
 947        .close          = erst_close_pstore,
 948        .read           = erst_reader,
 949        .write          = erst_writer,
 950        .erase          = erst_clearer
 951};
 952
 953#define CPER_CREATOR_PSTORE                                             \
 954        UUID_LE(0x75a574e3, 0x5052, 0x4b29, 0x8a, 0x8e, 0xbe, 0x2c,     \
 955                0x64, 0x90, 0xb8, 0x9d)
 956#define CPER_SECTION_TYPE_DMESG                                         \
 957        UUID_LE(0xc197e04e, 0xd545, 0x4a70, 0x9c, 0x17, 0xa5, 0x54,     \
 958                0x94, 0x19, 0xeb, 0x12)
 959#define CPER_SECTION_TYPE_MCE                                           \
 960        UUID_LE(0xfe08ffbe, 0x95e4, 0x4be7, 0xbc, 0x73, 0x40, 0x96,     \
 961                0x04, 0x4a, 0x38, 0xfc)
 962
 963struct cper_pstore_record {
 964        struct cper_record_header hdr;
 965        struct cper_section_descriptor sec_hdr;
 966        char data[];
 967} __packed;
 968
 969static int reader_pos;
 970
 971static int erst_open_pstore(struct pstore_info *psi)
 972{
 973        int rc;
 974
 975        if (erst_disable)
 976                return -ENODEV;
 977
 978        rc = erst_get_record_id_begin(&reader_pos);
 979
 980        return rc;
 981}
 982
 983static int erst_close_pstore(struct pstore_info *psi)
 984{
 985        erst_get_record_id_end();
 986
 987        return 0;
 988}
 989
 990static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, int *count,
 991                           struct timespec *time, char **buf,
 992                           struct pstore_info *psi)
 993{
 994        int rc;
 995        ssize_t len = 0;
 996        u64 record_id;
 997        struct cper_pstore_record *rcd;
 998        size_t rcd_len = sizeof(*rcd) + erst_info.bufsize;
 999
1000        if (erst_disable)
1001                return -ENODEV;
1002
1003        rcd = kmalloc(rcd_len, GFP_KERNEL);
1004        if (!rcd) {
1005                rc = -ENOMEM;
1006                goto out;
1007        }
1008skip:
1009        rc = erst_get_record_id_next(&reader_pos, &record_id);
1010        if (rc)
1011                goto out;
1012
1013        /* no more record */
1014        if (record_id == APEI_ERST_INVALID_RECORD_ID) {
1015                rc = -EINVAL;
1016                goto out;
1017        }
1018
1019        len = erst_read(record_id, &rcd->hdr, rcd_len);
1020        /* The record may be cleared by others, try read next record */
1021        if (len == -ENOENT)
1022                goto skip;
1023        else if (len < sizeof(*rcd)) {
1024                rc = -EIO;
1025                goto out;
1026        }
1027        if (uuid_le_cmp(rcd->hdr.creator_id, CPER_CREATOR_PSTORE) != 0)
1028                goto skip;
1029
1030        *buf = kmalloc(len, GFP_KERNEL);
1031        if (*buf == NULL) {
1032                rc = -ENOMEM;
1033                goto out;
1034        }
1035        memcpy(*buf, rcd->data, len - sizeof(*rcd));
1036        *id = record_id;
1037        if (uuid_le_cmp(rcd->sec_hdr.section_type,
1038                        CPER_SECTION_TYPE_DMESG) == 0)
1039                *type = PSTORE_TYPE_DMESG;
1040        else if (uuid_le_cmp(rcd->sec_hdr.section_type,
1041                             CPER_SECTION_TYPE_MCE) == 0)
1042                *type = PSTORE_TYPE_MCE;
1043        else
1044                *type = PSTORE_TYPE_UNKNOWN;
1045
1046        if (rcd->hdr.validation_bits & CPER_VALID_TIMESTAMP)
1047                time->tv_sec = rcd->hdr.timestamp;
1048        else
1049                time->tv_sec = 0;
1050        time->tv_nsec = 0;
1051
1052out:
1053        kfree(rcd);
1054        return (rc < 0) ? rc : (len - sizeof(*rcd));
1055}
1056
1057static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
1058                       u64 *id, unsigned int part, int count,
1059                       size_t size, struct pstore_info *psi)
1060{
1061        struct cper_pstore_record *rcd = (struct cper_pstore_record *)
1062                                        (erst_info.buf - sizeof(*rcd));
1063        int ret;
1064
1065        memset(rcd, 0, sizeof(*rcd));
1066        memcpy(rcd->hdr.signature, CPER_SIG_RECORD, CPER_SIG_SIZE);
1067        rcd->hdr.revision = CPER_RECORD_REV;
1068        rcd->hdr.signature_end = CPER_SIG_END;
1069        rcd->hdr.section_count = 1;
1070        rcd->hdr.error_severity = CPER_SEV_FATAL;
1071        /* timestamp valid. platform_id, partition_id are invalid */
1072        rcd->hdr.validation_bits = CPER_VALID_TIMESTAMP;
1073        rcd->hdr.timestamp = get_seconds();
1074        rcd->hdr.record_length = sizeof(*rcd) + size;
1075        rcd->hdr.creator_id = CPER_CREATOR_PSTORE;
1076        rcd->hdr.notification_type = CPER_NOTIFY_MCE;
1077        rcd->hdr.record_id = cper_next_record_id();
1078        rcd->hdr.flags = CPER_HW_ERROR_FLAGS_PREVERR;
1079
1080        rcd->sec_hdr.section_offset = sizeof(*rcd);
1081        rcd->sec_hdr.section_length = size;
1082        rcd->sec_hdr.revision = CPER_SEC_REV;
1083        /* fru_id and fru_text is invalid */
1084        rcd->sec_hdr.validation_bits = 0;
1085        rcd->sec_hdr.flags = CPER_SEC_PRIMARY;
1086        switch (type) {
1087        case PSTORE_TYPE_DMESG:
1088                rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG;
1089                break;
1090        case PSTORE_TYPE_MCE:
1091                rcd->sec_hdr.section_type = CPER_SECTION_TYPE_MCE;
1092                break;
1093        default:
1094                return -EINVAL;
1095        }
1096        rcd->sec_hdr.section_severity = CPER_SEV_FATAL;
1097
1098        ret = erst_write(&rcd->hdr);
1099        *id = rcd->hdr.record_id;
1100
1101        return ret;
1102}
1103
1104static int erst_clearer(enum pstore_type_id type, u64 id, int count,
1105                        struct timespec time, struct pstore_info *psi)
1106{
1107        return erst_clear(id);
1108}
1109
1110static int __init erst_init(void)
1111{
1112        int rc = 0;
1113        acpi_status status;
1114        struct apei_exec_context ctx;
1115        struct apei_resources erst_resources;
1116        struct resource *r;
1117        char *buf;
1118
1119        if (acpi_disabled)
1120                goto err;
1121
1122        if (erst_disable) {
1123                pr_info(ERST_PFX
1124        "Error Record Serialization Table (ERST) support is disabled.\n");
1125                goto err;
1126        }
1127
1128        status = acpi_get_table(ACPI_SIG_ERST, 0,
1129                                (struct acpi_table_header **)&erst_tab);
1130        if (status == AE_NOT_FOUND)
1131                goto err;
1132        else if (ACPI_FAILURE(status)) {
1133                const char *msg = acpi_format_exception(status);
1134                pr_err(ERST_PFX "Failed to get table, %s\n", msg);
1135                rc = -EINVAL;
1136                goto err;
1137        }
1138
1139        rc = erst_check_table(erst_tab);
1140        if (rc) {
1141                pr_err(FW_BUG ERST_PFX "ERST table is invalid\n");
1142                goto err;
1143        }
1144
1145        apei_resources_init(&erst_resources);
1146        erst_exec_ctx_init(&ctx);
1147        rc = apei_exec_collect_resources(&ctx, &erst_resources);
1148        if (rc)
1149                goto err_fini;
1150        rc = apei_resources_request(&erst_resources, "APEI ERST");
1151        if (rc)
1152                goto err_fini;
1153        rc = apei_exec_pre_map_gars(&ctx);
1154        if (rc)
1155                goto err_release;
1156        rc = erst_get_erange(&erst_erange);
1157        if (rc) {
1158                if (rc == -ENODEV)
1159                        pr_info(ERST_PFX
1160        "The corresponding hardware device or firmware implementation "
1161        "is not available.\n");
1162                else
1163                        pr_err(ERST_PFX
1164                               "Failed to get Error Log Address Range.\n");
1165                goto err_unmap_reg;
1166        }
1167
1168        r = request_mem_region(erst_erange.base, erst_erange.size, "APEI ERST");
1169        if (!r) {
1170                pr_err(ERST_PFX
1171                "Can not request iomem region <0x%16llx-0x%16llx> for ERST.\n",
1172                (unsigned long long)erst_erange.base,
1173                (unsigned long long)erst_erange.base + erst_erange.size);
1174                rc = -EIO;
1175                goto err_unmap_reg;
1176        }
1177        rc = -ENOMEM;
1178        erst_erange.vaddr = ioremap_cache(erst_erange.base,
1179                                          erst_erange.size);
1180        if (!erst_erange.vaddr)
1181                goto err_release_erange;
1182
1183        buf = kmalloc(erst_erange.size, GFP_KERNEL);
1184        spin_lock_init(&erst_info.buf_lock);
1185        if (buf) {
1186                erst_info.buf = buf + sizeof(struct cper_pstore_record);
1187                erst_info.bufsize = erst_erange.size -
1188                                    sizeof(struct cper_pstore_record);
1189                if (pstore_register(&erst_info)) {
1190                        pr_info(ERST_PFX "Could not register with persistent store\n");
1191                        kfree(buf);
1192                }
1193        }
1194
1195        pr_info(ERST_PFX
1196        "Error Record Serialization Table (ERST) support is initialized.\n");
1197
1198        return 0;
1199
1200err_release_erange:
1201        release_mem_region(erst_erange.base, erst_erange.size);
1202err_unmap_reg:
1203        apei_exec_post_unmap_gars(&ctx);
1204err_release:
1205        apei_resources_release(&erst_resources);
1206err_fini:
1207        apei_resources_fini(&erst_resources);
1208err:
1209        erst_disable = 1;
1210        return rc;
1211}
1212
1213device_initcall(erst_init);
1214