linux/fs/pstore/ram.c
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   1/*
   2 * RAM Oops/Panic logger
   3 *
   4 * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
   5 * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public License
   9 * version 2 as published by the Free Software Foundation.
  10 *
  11 * This program is distributed in the hope that it will be useful, but
  12 * WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 * General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  19 * 02110-1301 USA
  20 *
  21 */
  22
  23#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  24
  25#include <linux/kernel.h>
  26#include <linux/err.h>
  27#include <linux/module.h>
  28#include <linux/version.h>
  29#include <linux/pstore.h>
  30#include <linux/time.h>
  31#include <linux/io.h>
  32#include <linux/ioport.h>
  33#include <linux/platform_device.h>
  34#include <linux/slab.h>
  35#include <linux/compiler.h>
  36#include <linux/pstore_ram.h>
  37
  38#define RAMOOPS_KERNMSG_HDR "===="
  39#define MIN_MEM_SIZE 4096UL
  40
  41static ulong record_size = MIN_MEM_SIZE;
  42module_param(record_size, ulong, 0400);
  43MODULE_PARM_DESC(record_size,
  44                "size of each dump done on oops/panic");
  45
  46static ulong ramoops_console_size = MIN_MEM_SIZE;
  47module_param_named(console_size, ramoops_console_size, ulong, 0400);
  48MODULE_PARM_DESC(console_size, "size of kernel console log");
  49
  50static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
  51module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
  52MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
  53
  54static ulong mem_address;
  55module_param(mem_address, ulong, 0400);
  56MODULE_PARM_DESC(mem_address,
  57                "start of reserved RAM used to store oops/panic logs");
  58
  59static ulong mem_size;
  60module_param(mem_size, ulong, 0400);
  61MODULE_PARM_DESC(mem_size,
  62                "size of reserved RAM used to store oops/panic logs");
  63
  64static int dump_oops = 1;
  65module_param(dump_oops, int, 0600);
  66MODULE_PARM_DESC(dump_oops,
  67                "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  68
  69static int ramoops_ecc;
  70module_param_named(ecc, ramoops_ecc, int, 0600);
  71MODULE_PARM_DESC(ramoops_ecc,
  72                "if non-zero, the option enables ECC support and specifies "
  73                "ECC buffer size in bytes (1 is a special value, means 16 "
  74                "bytes ECC)");
  75
  76struct ramoops_context {
  77        struct persistent_ram_zone **przs;
  78        struct persistent_ram_zone *cprz;
  79        struct persistent_ram_zone *fprz;
  80        phys_addr_t phys_addr;
  81        unsigned long size;
  82        size_t record_size;
  83        size_t console_size;
  84        size_t ftrace_size;
  85        int dump_oops;
  86        int ecc_size;
  87        unsigned int max_dump_cnt;
  88        unsigned int dump_write_cnt;
  89        unsigned int dump_read_cnt;
  90        unsigned int console_read_cnt;
  91        unsigned int ftrace_read_cnt;
  92        struct pstore_info pstore;
  93};
  94
  95static struct platform_device *dummy;
  96static struct ramoops_platform_data *dummy_data;
  97
  98static int ramoops_pstore_open(struct pstore_info *psi)
  99{
 100        struct ramoops_context *cxt = psi->data;
 101
 102        cxt->dump_read_cnt = 0;
 103        cxt->console_read_cnt = 0;
 104        return 0;
 105}
 106
 107static struct persistent_ram_zone *
 108ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
 109                     u64 *id,
 110                     enum pstore_type_id *typep, enum pstore_type_id type,
 111                     bool update)
 112{
 113        struct persistent_ram_zone *prz;
 114        int i = (*c)++;
 115
 116        if (i >= max)
 117                return NULL;
 118
 119        prz = przs[i];
 120
 121        if (update) {
 122                /* Update old/shadowed buffer. */
 123                persistent_ram_save_old(prz);
 124                if (!persistent_ram_old_size(prz))
 125                        return NULL;
 126        }
 127
 128        *typep = type;
 129        *id = i;
 130
 131        return prz;
 132}
 133
 134static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 135                                   int *count, struct timespec *time,
 136                                   char **buf, struct pstore_info *psi)
 137{
 138        ssize_t size;
 139        struct ramoops_context *cxt = psi->data;
 140        struct persistent_ram_zone *prz;
 141
 142        prz = ramoops_get_next_prz(cxt->przs, &cxt->dump_read_cnt,
 143                                   cxt->max_dump_cnt, id, type,
 144                                   PSTORE_TYPE_DMESG, 1);
 145        if (!prz)
 146                prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
 147                                           1, id, type, PSTORE_TYPE_CONSOLE, 0);
 148        if (!prz)
 149                prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
 150                                           1, id, type, PSTORE_TYPE_FTRACE, 0);
 151        if (!prz)
 152                return 0;
 153
 154        /* TODO(kees): Bogus time for the moment. */
 155        time->tv_sec = 0;
 156        time->tv_nsec = 0;
 157
 158        size = persistent_ram_old_size(prz);
 159        *buf = kmalloc(size, GFP_KERNEL);
 160        if (*buf == NULL)
 161                return -ENOMEM;
 162        memcpy(*buf, persistent_ram_old(prz), size);
 163
 164        return size;
 165}
 166
 167static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
 168{
 169        char *hdr;
 170        struct timespec timestamp;
 171        size_t len;
 172
 173        /* Report zeroed timestamp if called before timekeeping has resumed. */
 174        if (__getnstimeofday(&timestamp)) {
 175                timestamp.tv_sec = 0;
 176                timestamp.tv_nsec = 0;
 177        }
 178        hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
 179                (long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000));
 180        WARN_ON_ONCE(!hdr);
 181        len = hdr ? strlen(hdr) : 0;
 182        persistent_ram_write(prz, hdr, len);
 183        kfree(hdr);
 184
 185        return len;
 186}
 187
 188static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
 189                                            enum kmsg_dump_reason reason,
 190                                            u64 *id, unsigned int part,
 191                                            const char *buf, size_t size,
 192                                            struct pstore_info *psi)
 193{
 194        struct ramoops_context *cxt = psi->data;
 195        struct persistent_ram_zone *prz;
 196        size_t hlen;
 197
 198        if (type == PSTORE_TYPE_CONSOLE) {
 199                if (!cxt->cprz)
 200                        return -ENOMEM;
 201                persistent_ram_write(cxt->cprz, buf, size);
 202                return 0;
 203        } else if (type == PSTORE_TYPE_FTRACE) {
 204                if (!cxt->fprz)
 205                        return -ENOMEM;
 206                persistent_ram_write(cxt->fprz, buf, size);
 207                return 0;
 208        }
 209
 210        if (type != PSTORE_TYPE_DMESG)
 211                return -EINVAL;
 212
 213        /* Out of the various dmesg dump types, ramoops is currently designed
 214         * to only store crash logs, rather than storing general kernel logs.
 215         */
 216        if (reason != KMSG_DUMP_OOPS &&
 217            reason != KMSG_DUMP_PANIC)
 218                return -EINVAL;
 219
 220        /* Skip Oopes when configured to do so. */
 221        if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
 222                return -EINVAL;
 223
 224        /* Explicitly only take the first part of any new crash.
 225         * If our buffer is larger than kmsg_bytes, this can never happen,
 226         * and if our buffer is smaller than kmsg_bytes, we don't want the
 227         * report split across multiple records.
 228         */
 229        if (part != 1)
 230                return -ENOSPC;
 231
 232        if (!cxt->przs)
 233                return -ENOSPC;
 234
 235        prz = cxt->przs[cxt->dump_write_cnt];
 236
 237        hlen = ramoops_write_kmsg_hdr(prz);
 238        if (size + hlen > prz->buffer_size)
 239                size = prz->buffer_size - hlen;
 240        persistent_ram_write(prz, buf, size);
 241
 242        cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
 243
 244        return 0;
 245}
 246
 247static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
 248                                struct timespec time, struct pstore_info *psi)
 249{
 250        struct ramoops_context *cxt = psi->data;
 251        struct persistent_ram_zone *prz;
 252
 253        switch (type) {
 254        case PSTORE_TYPE_DMESG:
 255                if (id >= cxt->max_dump_cnt)
 256                        return -EINVAL;
 257                prz = cxt->przs[id];
 258                break;
 259        case PSTORE_TYPE_CONSOLE:
 260                prz = cxt->cprz;
 261                break;
 262        case PSTORE_TYPE_FTRACE:
 263                prz = cxt->fprz;
 264                break;
 265        default:
 266                return -EINVAL;
 267        }
 268
 269        persistent_ram_free_old(prz);
 270        persistent_ram_zap(prz);
 271
 272        return 0;
 273}
 274
 275static struct ramoops_context oops_cxt = {
 276        .pstore = {
 277                .owner  = THIS_MODULE,
 278                .name   = "ramoops",
 279                .open   = ramoops_pstore_open,
 280                .read   = ramoops_pstore_read,
 281                .write_buf      = ramoops_pstore_write_buf,
 282                .erase  = ramoops_pstore_erase,
 283        },
 284};
 285
 286static void ramoops_free_przs(struct ramoops_context *cxt)
 287{
 288        int i;
 289
 290        if (!cxt->przs)
 291                return;
 292
 293        for (i = 0; !IS_ERR_OR_NULL(cxt->przs[i]); i++)
 294                persistent_ram_free(cxt->przs[i]);
 295        kfree(cxt->przs);
 296}
 297
 298static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
 299                             phys_addr_t *paddr, size_t dump_mem_sz)
 300{
 301        int err = -ENOMEM;
 302        int i;
 303
 304        if (!cxt->record_size)
 305                return 0;
 306
 307        if (*paddr + dump_mem_sz - cxt->phys_addr > cxt->size) {
 308                dev_err(dev, "no room for dumps\n");
 309                return -ENOMEM;
 310        }
 311
 312        cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
 313        if (!cxt->max_dump_cnt)
 314                return -ENOMEM;
 315
 316        cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
 317                             GFP_KERNEL);
 318        if (!cxt->przs) {
 319                dev_err(dev, "failed to initialize a prz array for dumps\n");
 320                return -ENOMEM;
 321        }
 322
 323        for (i = 0; i < cxt->max_dump_cnt; i++) {
 324                size_t sz = cxt->record_size;
 325
 326                cxt->przs[i] = persistent_ram_new(*paddr, sz, 0, cxt->ecc_size);
 327                if (IS_ERR(cxt->przs[i])) {
 328                        err = PTR_ERR(cxt->przs[i]);
 329                        dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 330                                sz, (unsigned long long)*paddr, err);
 331                        goto fail_prz;
 332                }
 333                *paddr += sz;
 334        }
 335
 336        return 0;
 337fail_prz:
 338        ramoops_free_przs(cxt);
 339        return err;
 340}
 341
 342static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
 343                            struct persistent_ram_zone **prz,
 344                            phys_addr_t *paddr, size_t sz, u32 sig)
 345{
 346        if (!sz)
 347                return 0;
 348
 349        if (*paddr + sz - cxt->phys_addr > cxt->size) {
 350                dev_err(dev, "no room for mem region (0x%zx@0x%llx) in (0x%lx@0x%llx)\n",
 351                        sz, (unsigned long long)*paddr,
 352                        cxt->size, (unsigned long long)cxt->phys_addr);
 353                return -ENOMEM;
 354        }
 355
 356        *prz = persistent_ram_new(*paddr, sz, sig, cxt->ecc_size);
 357        if (IS_ERR(*prz)) {
 358                int err = PTR_ERR(*prz);
 359
 360                dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 361                        sz, (unsigned long long)*paddr, err);
 362                return err;
 363        }
 364
 365        persistent_ram_zap(*prz);
 366
 367        *paddr += sz;
 368
 369        return 0;
 370}
 371
 372static int ramoops_probe(struct platform_device *pdev)
 373{
 374        struct device *dev = &pdev->dev;
 375        struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 376        struct ramoops_context *cxt = &oops_cxt;
 377        size_t dump_mem_sz;
 378        phys_addr_t paddr;
 379        int err = -EINVAL;
 380
 381        /* Only a single ramoops area allowed at a time, so fail extra
 382         * probes.
 383         */
 384        if (cxt->max_dump_cnt)
 385                goto fail_out;
 386
 387        if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
 388                        !pdata->ftrace_size)) {
 389                pr_err("The memory size and the record/console size must be "
 390                        "non-zero\n");
 391                goto fail_out;
 392        }
 393
 394        if (!is_power_of_2(pdata->mem_size))
 395                pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
 396        if (!is_power_of_2(pdata->record_size))
 397                pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 398        if (!is_power_of_2(pdata->console_size))
 399                pdata->console_size = rounddown_pow_of_two(pdata->console_size);
 400        if (!is_power_of_2(pdata->ftrace_size))
 401                pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
 402
 403        cxt->dump_read_cnt = 0;
 404        cxt->size = pdata->mem_size;
 405        cxt->phys_addr = pdata->mem_address;
 406        cxt->record_size = pdata->record_size;
 407        cxt->console_size = pdata->console_size;
 408        cxt->ftrace_size = pdata->ftrace_size;
 409        cxt->dump_oops = pdata->dump_oops;
 410        cxt->ecc_size = pdata->ecc_size;
 411
 412        paddr = cxt->phys_addr;
 413
 414        dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size;
 415        err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
 416        if (err)
 417                goto fail_out;
 418
 419        err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr,
 420                               cxt->console_size, 0);
 421        if (err)
 422                goto fail_init_cprz;
 423
 424        err = ramoops_init_prz(dev, cxt, &cxt->fprz, &paddr, cxt->ftrace_size,
 425                               LINUX_VERSION_CODE);
 426        if (err)
 427                goto fail_init_fprz;
 428
 429        if (!cxt->przs && !cxt->cprz && !cxt->fprz) {
 430                pr_err("memory size too small, minimum is %zu\n",
 431                        cxt->console_size + cxt->record_size +
 432                        cxt->ftrace_size);
 433                goto fail_cnt;
 434        }
 435
 436        cxt->pstore.data = cxt;
 437        /*
 438         * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
 439         * have to handle dumps, we must have at least record_size buffer. And
 440         * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
 441         * ZERO_SIZE_PTR).
 442         */
 443        if (cxt->console_size)
 444                cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
 445        cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
 446        cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
 447        spin_lock_init(&cxt->pstore.buf_lock);
 448        if (!cxt->pstore.buf) {
 449                pr_err("cannot allocate pstore buffer\n");
 450                goto fail_clear;
 451        }
 452
 453        err = pstore_register(&cxt->pstore);
 454        if (err) {
 455                pr_err("registering with pstore failed\n");
 456                goto fail_buf;
 457        }
 458
 459        /*
 460         * Update the module parameter variables as well so they are visible
 461         * through /sys/module/ramoops/parameters/
 462         */
 463        mem_size = pdata->mem_size;
 464        mem_address = pdata->mem_address;
 465        record_size = pdata->record_size;
 466        dump_oops = pdata->dump_oops;
 467
 468        pr_info("attached 0x%lx@0x%llx, ecc: %d\n",
 469                cxt->size, (unsigned long long)cxt->phys_addr,
 470                cxt->ecc_size);
 471
 472        return 0;
 473
 474fail_buf:
 475        kfree(cxt->pstore.buf);
 476fail_clear:
 477        cxt->pstore.bufsize = 0;
 478        cxt->max_dump_cnt = 0;
 479fail_cnt:
 480        kfree(cxt->fprz);
 481fail_init_fprz:
 482        kfree(cxt->cprz);
 483fail_init_cprz:
 484        ramoops_free_przs(cxt);
 485fail_out:
 486        return err;
 487}
 488
 489static int __exit ramoops_remove(struct platform_device *pdev)
 490{
 491#if 0
 492        /* TODO(kees): We cannot unload ramoops since pstore doesn't support
 493         * unregistering yet.
 494         */
 495        struct ramoops_context *cxt = &oops_cxt;
 496
 497        iounmap(cxt->virt_addr);
 498        release_mem_region(cxt->phys_addr, cxt->size);
 499        cxt->max_dump_cnt = 0;
 500
 501        /* TODO(kees): When pstore supports unregistering, call it here. */
 502        kfree(cxt->pstore.buf);
 503        cxt->pstore.bufsize = 0;
 504
 505        return 0;
 506#endif
 507        return -EBUSY;
 508}
 509
 510static struct platform_driver ramoops_driver = {
 511        .probe          = ramoops_probe,
 512        .remove         = __exit_p(ramoops_remove),
 513        .driver         = {
 514                .name   = "ramoops",
 515                .owner  = THIS_MODULE,
 516        },
 517};
 518
 519static void ramoops_register_dummy(void)
 520{
 521        if (!mem_size)
 522                return;
 523
 524        pr_info("using module parameters\n");
 525
 526        dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
 527        if (!dummy_data) {
 528                pr_info("could not allocate pdata\n");
 529                return;
 530        }
 531
 532        dummy_data->mem_size = mem_size;
 533        dummy_data->mem_address = mem_address;
 534        dummy_data->record_size = record_size;
 535        dummy_data->console_size = ramoops_console_size;
 536        dummy_data->ftrace_size = ramoops_ftrace_size;
 537        dummy_data->dump_oops = dump_oops;
 538        /*
 539         * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 540         * (using 1 byte for ECC isn't much of use anyway).
 541         */
 542        dummy_data->ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 543
 544        dummy = platform_device_register_data(NULL, "ramoops", -1,
 545                        dummy_data, sizeof(struct ramoops_platform_data));
 546        if (IS_ERR(dummy)) {
 547                pr_info("could not create platform device: %ld\n",
 548                        PTR_ERR(dummy));
 549        }
 550}
 551
 552static int __init ramoops_init(void)
 553{
 554        ramoops_register_dummy();
 555        return platform_driver_register(&ramoops_driver);
 556}
 557postcore_initcall(ramoops_init);
 558
 559static void __exit ramoops_exit(void)
 560{
 561        platform_driver_unregister(&ramoops_driver);
 562        platform_device_unregister(dummy);
 563        kfree(dummy_data);
 564}
 565module_exit(ramoops_exit);
 566
 567MODULE_LICENSE("GPL");
 568MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 569MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
 570
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