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/pstore_ram.h>
  36
  37#define RAMOOPS_KERNMSG_HDR "===="
  38#define MIN_MEM_SIZE 4096UL
  39
  40static ulong record_size = MIN_MEM_SIZE;
  41module_param(record_size, ulong, 0400);
  42MODULE_PARM_DESC(record_size,
  43                "size of each dump done on oops/panic");
  44
  45static ulong ramoops_console_size = MIN_MEM_SIZE;
  46module_param_named(console_size, ramoops_console_size, ulong, 0400);
  47MODULE_PARM_DESC(console_size, "size of kernel console log");
  48
  49static ulong ramoops_ftrace_size = MIN_MEM_SIZE;
  50module_param_named(ftrace_size, ramoops_ftrace_size, ulong, 0400);
  51MODULE_PARM_DESC(ftrace_size, "size of ftrace log");
  52
  53static ulong mem_address;
  54module_param(mem_address, ulong, 0400);
  55MODULE_PARM_DESC(mem_address,
  56                "start of reserved RAM used to store oops/panic logs");
  57
  58static ulong mem_size;
  59module_param(mem_size, ulong, 0400);
  60MODULE_PARM_DESC(mem_size,
  61                "size of reserved RAM used to store oops/panic logs");
  62
  63static int dump_oops = 1;
  64module_param(dump_oops, int, 0600);
  65MODULE_PARM_DESC(dump_oops,
  66                "set to 1 to dump oopses, 0 to only dump panics (default 1)");
  67
  68static int ramoops_ecc;
  69module_param_named(ecc, ramoops_ecc, int, 0600);
  70MODULE_PARM_DESC(ramoops_ecc,
  71                "if non-zero, the option enables ECC support and specifies "
  72                "ECC buffer size in bytes (1 is a special value, means 16 "
  73                "bytes ECC)");
  74
  75struct ramoops_context {
  76        struct persistent_ram_zone **przs;
  77        struct persistent_ram_zone *cprz;
  78        struct persistent_ram_zone *fprz;
  79        phys_addr_t phys_addr;
  80        unsigned long size;
  81        size_t record_size;
  82        size_t console_size;
  83        size_t ftrace_size;
  84        int dump_oops;
  85        int ecc_size;
  86        unsigned int max_dump_cnt;
  87        unsigned int dump_write_cnt;
  88        unsigned int dump_read_cnt;
  89        unsigned int console_read_cnt;
  90        unsigned int ftrace_read_cnt;
  91        struct pstore_info pstore;
  92};
  93
  94static struct platform_device *dummy;
  95static struct ramoops_platform_data *dummy_data;
  96
  97static int ramoops_pstore_open(struct pstore_info *psi)
  98{
  99        struct ramoops_context *cxt = psi->data;
 100
 101        cxt->dump_read_cnt = 0;
 102        cxt->console_read_cnt = 0;
 103        return 0;
 104}
 105
 106static struct persistent_ram_zone *
 107ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
 108                     u64 *id,
 109                     enum pstore_type_id *typep, enum pstore_type_id type,
 110                     bool update)
 111{
 112        struct persistent_ram_zone *prz;
 113        int i = (*c)++;
 114
 115        if (i >= max)
 116                return NULL;
 117
 118        prz = przs[i];
 119
 120        if (update) {
 121                /* Update old/shadowed buffer. */
 122                persistent_ram_save_old(prz);
 123                if (!persistent_ram_old_size(prz))
 124                        return NULL;
 125        }
 126
 127        *typep = type;
 128        *id = i;
 129
 130        return prz;
 131}
 132
 133static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 134                                   struct timespec *time,
 135                                   char **buf,
 136                                   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 timeval timestamp;
 171        size_t len;
 172
 173        do_gettimeofday(&timestamp);
 174        hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
 175                (long)timestamp.tv_sec, (long)timestamp.tv_usec);
 176        WARN_ON_ONCE(!hdr);
 177        len = hdr ? strlen(hdr) : 0;
 178        persistent_ram_write(prz, hdr, len);
 179        kfree(hdr);
 180
 181        return len;
 182}
 183
 184
 185static int 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        pdata->mem_size = rounddown_pow_of_two(pdata->mem_size);
 378        pdata->record_size = rounddown_pow_of_two(pdata->record_size);
 379        pdata->console_size = rounddown_pow_of_two(pdata->console_size);
 380        pdata->ftrace_size = rounddown_pow_of_two(pdata->ftrace_size);
 381
 382        cxt->dump_read_cnt = 0;
 383        cxt->size = pdata->mem_size;
 384        cxt->phys_addr = pdata->mem_address;
 385        cxt->record_size = pdata->record_size;
 386        cxt->console_size = pdata->console_size;
 387        cxt->ftrace_size = pdata->ftrace_size;
 388        cxt->dump_oops = pdata->dump_oops;
 389        cxt->ecc_size = pdata->ecc_size;
 390
 391        paddr = cxt->phys_addr;
 392
 393        dump_mem_sz = cxt->size - cxt->console_size - cxt->ftrace_size;
 394        err = ramoops_init_przs(dev, cxt, &paddr, dump_mem_sz);
 395        if (err)
 396                goto fail_out;
 397
 398        err = ramoops_init_prz(dev, cxt, &cxt->cprz, &paddr,
 399                               cxt->console_size, 0);
 400        if (err)
 401                goto fail_init_cprz;
 402
 403        err = ramoops_init_prz(dev, cxt, &cxt->fprz, &paddr, cxt->ftrace_size,
 404                               LINUX_VERSION_CODE);
 405        if (err)
 406                goto fail_init_fprz;
 407
 408        if (!cxt->przs && !cxt->cprz && !cxt->fprz) {
 409                pr_err("memory size too small, minimum is %zu\n",
 410                        cxt->console_size + cxt->record_size +
 411                        cxt->ftrace_size);
 412                goto fail_cnt;
 413        }
 414
 415        cxt->pstore.data = cxt;
 416        /*
 417         * Console can handle any buffer size, so prefer dumps buffer
 418         * size since usually it is smaller.
 419         */
 420        if (cxt->przs)
 421                cxt->pstore.bufsize = cxt->przs[0]->buffer_size;
 422        else
 423                cxt->pstore.bufsize = cxt->cprz->buffer_size;
 424        cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
 425        spin_lock_init(&cxt->pstore.buf_lock);
 426        if (!cxt->pstore.buf) {
 427                pr_err("cannot allocate pstore buffer\n");
 428                goto fail_clear;
 429        }
 430
 431        err = pstore_register(&cxt->pstore);
 432        if (err) {
 433                pr_err("registering with pstore failed\n");
 434                goto fail_buf;
 435        }
 436
 437        /*
 438         * Update the module parameter variables as well so they are visible
 439         * through /sys/module/ramoops/parameters/
 440         */
 441        mem_size = pdata->mem_size;
 442        mem_address = pdata->mem_address;
 443        record_size = pdata->record_size;
 444        dump_oops = pdata->dump_oops;
 445
 446        pr_info("attached 0x%lx@0x%llx, ecc: %d\n",
 447                cxt->size, (unsigned long long)cxt->phys_addr,
 448                cxt->ecc_size);
 449
 450        return 0;
 451
 452fail_buf:
 453        kfree(cxt->pstore.buf);
 454fail_clear:
 455        cxt->pstore.bufsize = 0;
 456        cxt->max_dump_cnt = 0;
 457fail_cnt:
 458        kfree(cxt->fprz);
 459fail_init_fprz:
 460        kfree(cxt->cprz);
 461fail_init_cprz:
 462        ramoops_free_przs(cxt);
 463fail_out:
 464        return err;
 465}
 466
 467static int __exit ramoops_remove(struct platform_device *pdev)
 468{
 469#if 0
 470        /* TODO(kees): We cannot unload ramoops since pstore doesn't support
 471         * unregistering yet.
 472         */
 473        struct ramoops_context *cxt = &oops_cxt;
 474
 475        iounmap(cxt->virt_addr);
 476        release_mem_region(cxt->phys_addr, cxt->size);
 477        cxt->max_dump_cnt = 0;
 478
 479        /* TODO(kees): When pstore supports unregistering, call it here. */
 480        kfree(cxt->pstore.buf);
 481        cxt->pstore.bufsize = 0;
 482
 483        return 0;
 484#endif
 485        return -EBUSY;
 486}
 487
 488static struct platform_driver ramoops_driver = {
 489        .probe          = ramoops_probe,
 490        .remove         = __exit_p(ramoops_remove),
 491        .driver         = {
 492                .name   = "ramoops",
 493                .owner  = THIS_MODULE,
 494        },
 495};
 496
 497static void ramoops_register_dummy(void)
 498{
 499        if (!mem_size)
 500                return;
 501
 502        pr_info("using module parameters\n");
 503
 504        dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
 505        if (!dummy_data) {
 506                pr_info("could not allocate pdata\n");
 507                return;
 508        }
 509
 510        dummy_data->mem_size = mem_size;
 511        dummy_data->mem_address = mem_address;
 512        dummy_data->record_size = record_size;
 513        dummy_data->console_size = ramoops_console_size;
 514        dummy_data->ftrace_size = ramoops_ftrace_size;
 515        dummy_data->dump_oops = dump_oops;
 516        /*
 517         * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 518         * (using 1 byte for ECC isn't much of use anyway).
 519         */
 520        dummy_data->ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 521
 522        dummy = platform_device_register_data(NULL, "ramoops", -1,
 523                        dummy_data, sizeof(struct ramoops_platform_data));
 524        if (IS_ERR(dummy)) {
 525                pr_info("could not create platform device: %ld\n",
 526                        PTR_ERR(dummy));
 527        }
 528}
 529
 530static int __init ramoops_init(void)
 531{
 532        ramoops_register_dummy();
 533        return platform_driver_register(&ramoops_driver);
 534}
 535postcore_initcall(ramoops_init);
 536
 537static void __exit ramoops_exit(void)
 538{
 539        platform_driver_unregister(&ramoops_driver);
 540        kfree(dummy_data);
 541}
 542module_exit(ramoops_exit);
 543
 544MODULE_LICENSE("GPL");
 545MODULE_AUTHOR("Marco Stornelli <marco.stornelli@gmail.com>");
 546MODULE_DESCRIPTION("RAM Oops/Panic logger/driver");
 547
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