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                                   struct timespec *time,
 136                                   char **buf,
 137                                   struct pstore_info *psi)
 138{
 139        ssize_t size;
 140        struct ramoops_context *cxt = psi->data;
 141        struct persistent_ram_zone *prz;
 142
 143        prz = ramoops_get_next_prz(cxt->przs, &cxt->dump_read_cnt,
 144                                   cxt->max_dump_cnt, id, type,
 145                                   PSTORE_TYPE_DMESG, 1);
 146        if (!prz)
 147                prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
 148                                           1, id, type, PSTORE_TYPE_CONSOLE, 0);
 149        if (!prz)
 150                prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
 151                                           1, id, type, PSTORE_TYPE_FTRACE, 0);
 152        if (!prz)
 153                return 0;
 154
 155        /* TODO(kees): Bogus time for the moment. */
 156        time->tv_sec = 0;
 157        time->tv_nsec = 0;
 158
 159        size = persistent_ram_old_size(prz);
 160        *buf = kmalloc(size, GFP_KERNEL);
 161        if (*buf == NULL)
 162                return -ENOMEM;
 163        memcpy(*buf, persistent_ram_old(prz), size);
 164
 165        return size;
 166}
 167
 168static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
 169{
 170        char *hdr;
 171        struct timeval timestamp;
 172        size_t len;
 173
 174        do_gettimeofday(&timestamp);
 175        hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
 176                (long)timestamp.tv_sec, (long)timestamp.tv_usec);
 177        WARN_ON_ONCE(!hdr);
 178        len = hdr ? strlen(hdr) : 0;
 179        persistent_ram_write(prz, hdr, len);
 180        kfree(hdr);
 181
 182        return len;
 183}
 184
 185static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
 186                                            enum kmsg_dump_reason reason,
 187                                            u64 *id, unsigned int part,
 188                                            const char *buf, size_t size,
 189                                            struct pstore_info *psi)
 190{
 191        struct ramoops_context *cxt = psi->data;
 192        struct persistent_ram_zone *prz = cxt->przs[cxt->dump_write_cnt];
 193        size_t hlen;
 194
 195        if (type == PSTORE_TYPE_CONSOLE) {
 196                if (!cxt->cprz)
 197                        return -ENOMEM;
 198                persistent_ram_write(cxt->cprz, buf, size);
 199                return 0;
 200        } else if (type == PSTORE_TYPE_FTRACE) {
 201                if (!cxt->fprz)
 202                        return -ENOMEM;
 203                persistent_ram_write(cxt->fprz, buf, size);
 204                return 0;
 205        }
 206
 207        if (type != PSTORE_TYPE_DMESG)
 208                return -EINVAL;
 209
 210        /* Out of the various dmesg dump types, ramoops is currently designed
 211         * to only store crash logs, rather than storing general kernel logs.
 212         */
 213        if (reason != KMSG_DUMP_OOPS &&
 214            reason != KMSG_DUMP_PANIC)
 215                return -EINVAL;
 216
 217        /* Skip Oopes when configured to do so. */
 218        if (reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
 219                return -EINVAL;
 220
 221        /* Explicitly only take the first part of any new crash.
 222         * If our buffer is larger than kmsg_bytes, this can never happen,
 223         * and if our buffer is smaller than kmsg_bytes, we don't want the
 224         * report split across multiple records.
 225         */
 226        if (part != 1)
 227                return -ENOSPC;
 228
 229        hlen = ramoops_write_kmsg_hdr(prz);
 230        if (size + hlen > prz->buffer_size)
 231                size = prz->buffer_size - hlen;
 232        persistent_ram_write(prz, buf, size);
 233
 234        cxt->dump_write_cnt = (cxt->dump_write_cnt + 1) % cxt->max_dump_cnt;
 235
 236        return 0;
 237}
 238
 239static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
 240                                struct pstore_info *psi)
 241{
 242        struct ramoops_context *cxt = psi->data;
 243        struct persistent_ram_zone *prz;
 244
 245        switch (type) {
 246        case PSTORE_TYPE_DMESG:
 247                if (id >= cxt->max_dump_cnt)
 248                        return -EINVAL;
 249                prz = cxt->przs[id];
 250                break;
 251        case PSTORE_TYPE_CONSOLE:
 252                prz = cxt->cprz;
 253                break;
 254        case PSTORE_TYPE_FTRACE:
 255                prz = cxt->fprz;
 256                break;
 257        default:
 258                return -EINVAL;
 259        }
 260
 261        persistent_ram_free_old(prz);
 262        persistent_ram_zap(prz);
 263
 264        return 0;
 265}
 266
 267static struct ramoops_context oops_cxt = {
 268        .pstore = {
 269                .owner  = THIS_MODULE,
 270                .name   = "ramoops",
 271                .open   = ramoops_pstore_open,
 272                .read   = ramoops_pstore_read,
 273                .write_buf      = ramoops_pstore_write_buf,
 274                .erase  = ramoops_pstore_erase,
 275        },
 276};
 277
 278static void ramoops_free_przs(struct ramoops_context *cxt)
 279{
 280        int i;
 281
 282        if (!cxt->przs)
 283                return;
 284
 285        for (i = 0; !IS_ERR_OR_NULL(cxt->przs[i]); i++)
 286                persistent_ram_free(cxt->przs[i]);
 287        kfree(cxt->przs);
 288}
 289
 290static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt,
 291                              phys_addr_t *paddr, size_t dump_mem_sz)
 292{
 293        int err = -ENOMEM;
 294        int i;
 295
 296        if (!cxt->record_size)
 297                return 0;
 298
 299        cxt->max_dump_cnt = dump_mem_sz / cxt->record_size;
 300        if (!cxt->max_dump_cnt)
 301                return -ENOMEM;
 302
 303        cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_dump_cnt,
 304                             GFP_KERNEL);
 305        if (!cxt->przs) {
 306                dev_err(dev, "failed to initialize a prz array for dumps\n");
 307                return -ENOMEM;
 308        }
 309
 310        for (i = 0; i < cxt->max_dump_cnt; i++) {
 311                size_t sz = cxt->record_size;
 312
 313                cxt->przs[i] = persistent_ram_new(*paddr, sz, 0, cxt->ecc_size);
 314                if (IS_ERR(cxt->przs[i])) {
 315                        err = PTR_ERR(cxt->przs[i]);
 316                        dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 317                                sz, (unsigned long long)*paddr, err);
 318                        goto fail_prz;
 319                }
 320                *paddr += sz;
 321        }
 322
 323        return 0;
 324fail_prz:
 325        ramoops_free_przs(cxt);
 326        return err;
 327}
 328
 329static int ramoops_init_prz(struct device *dev, struct ramoops_context *cxt,
 330                            struct persistent_ram_zone **prz,
 331                            phys_addr_t *paddr, size_t sz, u32 sig)
 332{
 333        if (!sz)
 334                return 0;
 335
 336        if (*paddr + sz > *paddr + cxt->size)
 337                return -ENOMEM;
 338
 339        *prz = persistent_ram_new(*paddr, sz, sig, cxt->ecc_size);
 340        if (IS_ERR(*prz)) {
 341                int err = PTR_ERR(*prz);
 342
 343                dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
 344                        sz, (unsigned long long)*paddr, err);
 345                return err;
 346        }
 347
 348        persistent_ram_zap(*prz);
 349
 350        *paddr += sz;
 351
 352        return 0;
 353}
 354
 355static int __devinit ramoops_probe(struct platform_device *pdev)
 356{
 357        struct device *dev = &pdev->dev;
 358        struct ramoops_platform_data *pdata = pdev->dev.platform_data;
 359        struct ramoops_context *cxt = &oops_cxt;
 360        size_t dump_mem_sz;
 361        phys_addr_t paddr;
 362        int err = -EINVAL;
 363
 364        /* Only a single ramoops area allowed at a time, so fail extra
 365         * probes.
 366         */
 367        if (cxt->max_dump_cnt)
 368                goto fail_out;
 369
 370        if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size &&
 371                        !pdata->ftrace_size)) {
 372                pr_err("The memory size and the record/console size must be "
 373                        "non-zero\n");
 374                goto fail_out;
 375        }
 376
 377        if (!is_power_of_2(pdata->mem_size))
 378                pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
 379        if (!is_power_of_2(pdata->record_size))
 380                pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 381        if (!is_power_of_2(pdata->console_size))
 382                pdata->console_size = rounddown_pow_of_two(pdata->console_size);
 383        if (!is_power_of_2(pdata->ftrace_size))
 384                pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
 385
 386        cxt->dump_read_cnt = 0;
 387        cxt->size = pdata->mem_size;
 388        cxt->phys_addr = pdata->mem_address;
 389        cxt->record_size = pdata->record_size;
 390        cxt->console_size = pdata->console_size;
 391        cxt->ftrace_size = pdata->ftrace_size;
 392        cxt->dump_oops = pdata->dump_oops;
 393        cxt->ecc_size = pdata->ecc_size;
 394
 395        paddr = cxt->phys_addr;
 396
 397        dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size;
 398        err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
 399        if (err)
 400                goto fail_out;
 401
 402        err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr,
 403                               cxt->console_size, 0);
 404        if (err)
 405                goto fail_init_cprz;
 406
 407        err = ramoops_init_prz(dev, cxt, &cxt->fprz, &paddr, cxt->ftrace_size,
 408                               LINUX_VERSION_CODE);
 409        if (err)
 410                goto fail_init_fprz;
 411
 412        if (!cxt->przs && !cxt->cprz && !cxt->fprz) {
 413                pr_err("memory size too small, minimum is %zu\n",
 414                        cxt->console_size + cxt->record_size +
 415                        cxt->ftrace_size);
 416                goto fail_cnt;
 417        }
 418
 419        cxt->pstore.data = cxt;
 420        /*
 421         * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
 422         * have to handle dumps, we must have at least record_size buffer. And
 423         * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
 424         * ZERO_SIZE_PTR).
 425         */
 426        if (cxt->console_size)
 427                cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
 428        cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
 429        cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
 430        spin_lock_init(&cxt->pstore.buf_lock);
 431        if (!cxt->pstore.buf) {
 432                pr_err("cannot allocate pstore buffer\n");
 433                goto fail_clear;
 434        }
 435
 436        err = pstore_register(&cxt->pstore);
 437        if (err) {
 438                pr_err("registering with pstore failed\n");
 439                goto fail_buf;
 440        }
 441
 442        /*
 443         * Update the module parameter variables as well so they are visible
 444         * through /sys/module/ramoops/parameters/
 445         */
 446        mem_size = pdata->mem_size;
 447        mem_address = pdata->mem_address;
 448        record_size = pdata->record_size;
 449        dump_oops = pdata->dump_oops;
 450
 451        pr_info("attached 0x%lx@0x%llx, ecc: %d\n",
 452                cxt->size, (unsigned long long)cxt->phys_addr,
 453                cxt->ecc_size);
 454
 455        return 0;
 456
 457fail_buf:
 458        kfree(cxt->pstore.buf);
 459fail_clear:
 460        cxt->pstore.bufsize = 0;
 461        cxt->max_dump_cnt = 0;
 462fail_cnt:
 463        kfree(cxt->fprz);
 464fail_init_fprz:
 465        kfree(cxt->cprz);
 466fail_init_cprz:
 467        ramoops_free_przs(cxt);
 468fail_out:
 469        return err;
 470}
 471
 472static int __exit ramoops_remove(struct platform_device *pdev)
 473{
 474#if 0
 475        /* TODO(kees): We cannot unload ramoops since pstore doesn't support
 476         * unregistering yet.
 477         */
 478        struct ramoops_context *cxt = &oops_cxt;
 479
 480        iounmap(cxt->virt_addr);
 481        release_mem_region(cxt->phys_addr, cxt->size);
 482        cxt->max_dump_cnt = 0;
 483
 484        /* TODO(kees): When pstore supports unregistering, call it here. */
 485        kfree(cxt->pstore.buf);
 486        cxt->pstore.bufsize = 0;
 487
 488        return 0;
 489#endif
 490        return -EBUSY;
 491}
 492
 493static struct platform_driver ramoops_driver = {
 494        .probe          = ramoops_probe,
 495        .remove         = __exit_p(ramoops_remove),
 496        .driver         = {
 497                .name   = "ramoops",
 498                .owner  = THIS_MODULE,
 499        },
 500};
 501
 502static void ramoops_register_dummy(void)
 503{
 504        if (!mem_size)
 505                return;
 506
 507        pr_info("using module parameters\n");
 508
 509        dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
 510        if (!dummy_data) {
 511                pr_info("could not allocate pdata\n");
 512                return;
 513        }
 514
 515        dummy_data->mem_size = mem_size;
 516        dummy_data->mem_address = mem_address;
 517        dummy_data->record_size = record_size;
 518        dummy_data->console_size = ramoops_console_size;
 519        dummy_data->ftrace_size = ramoops_ftrace_size;
 520        dummy_data->dump_oops = dump_oops;
 521        /*
 522         * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 523         * (using 1 byte for ECC isn't much of use anyway).
 524         */
 525        dummy_data->ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 526
 527        dummy = platform_device_register_data(NULL, "ramoops", -1,
 528                        dummy_data, sizeof(struct ramoops_platform_data));
 529        if (IS_ERR(dummy)) {
 530                pr_info("could not create platform device: %ld\n",
 531                        PTR_ERR(dummy));
 532        }
 533}
 534
 535static int __init ramoops_init(void)
 536{
 537        ramoops_register_dummy();
 538        return platform_driver_register(&ramoops_driver);
 539}
 540postcore_initcall(ramoops_init);
 541
 542static void __exit ramoops_exit(void)
 543{
 544        platform_driver_unregister(&ramoops_driver);
 545        platform_device_unregister(dummy);
 546        kfree(dummy_data);
 547}
 548module_exit(ramoops_exit);
 549
 550MODULE_LICENSE("GPL");
 551MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 552MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
 553
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