arch/powerpc/kernel/nvram_64.c

   1 /*
   2  *  c 2001 PPC 64 Team, IBM Corp
   3  *
   4  *      This program is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU General Public License
   6  *      as published by the Free Software Foundation; either version
   7  *      2 of the License, or (at your option) any later version.
   8  *
   9  * /dev/nvram driver for PPC64
  10  *
  11  * This perhaps should live in drivers/char
  12  *
  13  * TODO: Split the /dev/nvram part (that one can use
  14  *       drivers/char/generic_nvram.c) from the arch & partition
  15  *       parsing code.
  16  */
  17
  18 #include <linux/types.h>
  19 #include <linux/errno.h>
  20 #include <linux/fs.h>
  21 #include <linux/miscdevice.h>
  22 #include <linux/fcntl.h>
  23 #include <linux/nvram.h>
  24 #include <linux/init.h>
  25 #include <linux/slab.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/kmsg_dump.h>
  28 #include <linux/pagemap.h>
  29 #include <linux/pstore.h>
  30 #include <linux/zlib.h>
  31 #include <asm/uaccess.h>
  32 #include <asm/nvram.h>
  33 #include <asm/rtas.h>
  34 #include <asm/prom.h>
  35 #include <asm/machdep.h>
  36
  37 #undef DEBUG_NVRAM
  38
  39 #define NVRAM_HEADER_LEN        sizeof(struct nvram_header)
  40 #define NVRAM_BLOCK_LEN         NVRAM_HEADER_LEN
  41
  42 /* If change this size, then change the size of NVNAME_LEN */
  43 struct nvram_header {
  44         unsigned char signature;
  45         unsigned char checksum;
  46         unsigned short length;
  47         /* Terminating null required only for names < 12 chars. */
  48         char name[12];
  49 };
  50
  51 struct nvram_partition {
  52         struct list_head partition;
  53         struct nvram_header header;
  54         unsigned int index;
  55 };
  56
  57 static LIST_HEAD(nvram_partitions);
  58
  59 #ifdef CONFIG_PPC_PSERIES
  60 struct nvram_os_partition rtas_log_partition = {
  61         .name = "ibm,rtas-log",
  62         .req_size = 2079,
  63         .min_size = 1055,
  64         .index = -1,
  65         .os_partition = true
  66 };
  67 #endif
  68
  69 struct nvram_os_partition oops_log_partition = {
  70         .name = "lnx,oops-log",
  71         .req_size = 4000,
  72         .min_size = 2000,
  73         .index = -1,
  74         .os_partition = true
  75 };
  76
  77 static const char *nvram_os_partitions[] = {
  78 #ifdef CONFIG_PPC_PSERIES
  79         "ibm,rtas-log",
  80 #endif
  81         "lnx,oops-log",
  82         NULL
  83 };
  84
  85 static void oops_to_nvram(struct kmsg_dumper *dumper,
  86                           enum kmsg_dump_reason reason);
  87
  88 static struct kmsg_dumper nvram_kmsg_dumper = {
  89         .dump = oops_to_nvram
  90 };
  91
  92 /*
  93  * For capturing and compressing an oops or panic report...
  94
  95  * big_oops_buf[] holds the uncompressed text we're capturing.
  96  *
  97  * oops_buf[] holds the compressed text, preceded by a oops header.
  98  * oops header has u16 holding the version of oops header (to differentiate
  99  * between old and new format header) followed by u16 holding the length of
 100  * the compressed* text (*Or uncompressed, if compression fails.) and u64
 101  * holding the timestamp. oops_buf[] gets written to NVRAM.
 102  *
 103  * oops_log_info points to the header. oops_data points to the compressed text.
 104  *
 105  * +- oops_buf
 106  * |                                   +- oops_data
 107  * v                                   v
 108  * +-----------+-----------+-----------+------------------------+
 109  * | version   | length    | timestamp | text                   |
 110  * | (2 bytes) | (2 bytes) | (8 bytes) | (oops_data_sz bytes)   |
 111  * +-----------+-----------+-----------+------------------------+
 112  * ^
 113  * +- oops_log_info
 114  *
 115  * We preallocate these buffers during init to avoid kmalloc during oops/panic.
 116  */
 117 static size_t big_oops_buf_sz;
 118 static char *big_oops_buf, *oops_buf;
 119 static char *oops_data;
 120 static size_t oops_data_sz;
 121
 122 /* Compression parameters */
 123 #define COMPR_LEVEL 6
 124 #define WINDOW_BITS 12
 125 #define MEM_LEVEL 4
 126 static struct z_stream_s stream;
 127
 128 #ifdef CONFIG_PSTORE
 129 #ifdef CONFIG_PPC_POWERNV
 130 static struct nvram_os_partition skiboot_partition = {
 131         .name = "ibm,skiboot",
 132         .index = -1,
 133         .os_partition = false
 134 };
 135 #endif
 136
 137 #ifdef CONFIG_PPC_PSERIES
 138 static struct nvram_os_partition of_config_partition = {
 139         .name = "of-config",
 140         .index = -1,
 141         .os_partition = false
 142 };
 143 #endif
 144
 145 static struct nvram_os_partition common_partition = {
 146         .name = "common",
 147         .index = -1,
 148         .os_partition = false
 149 };
 150
 151 static enum pstore_type_id nvram_type_ids[] = {
 152         PSTORE_TYPE_DMESG,
 153         PSTORE_TYPE_PPC_COMMON,
 154         -1,
 155         -1,
 156         -1
 157 };
 158 static int read_type;
 159 #endif
 160
 161 /* nvram_write_os_partition
 162  *
 163  * We need to buffer the error logs into nvram to ensure that we have
 164  * the failure information to decode.  If we have a severe error there
 165  * is no way to guarantee that the OS or the machine is in a state to
 166  * get back to user land and write the error to disk.  For example if
 167  * the SCSI device driver causes a Machine Check by writing to a bad
 168  * IO address, there is no way of guaranteeing that the device driver
 169  * is in any state that is would also be able to write the error data
 170  * captured to disk, thus we buffer it in NVRAM for analysis on the
 171  * next boot.
 172  *
 173  * In NVRAM the partition containing the error log buffer will looks like:
 174  * Header (in bytes):
 175  * +-----------+----------+--------+------------+------------------+
 176  * | signature | checksum | length | name       | data             |
 177  * |0          |1         |2      3|4         15|16        length-1|
 178  * +-----------+----------+--------+------------+------------------+
 179  *
 180  * The 'data' section would look like (in bytes):
 181  * +--------------+------------+-----------------------------------+
 182  * | event_logged | sequence # | error log                         |
 183  * |0            3|4          7|8                  error_log_size-1|
 184  * +--------------+------------+-----------------------------------+
 185  *
 186  * event_logged: 0 if event has not been logged to syslog, 1 if it has
 187  * sequence #: The unique sequence # for each event. (until it wraps)
 188  * error log: The error log from event_scan
 189  */
 190 int nvram_write_os_partition(struct nvram_os_partition *part,
 191                              char *buff, int length,
 192                              unsigned int err_type,
 193                              unsigned int error_log_cnt)
 194 {
 195         int rc;
 196         loff_t tmp_index;
 197         struct err_log_info info;
 198
 199         if (part->index == -1)
 200                 return -ESPIPE;
 201
 202         if (length > part->size)
 203                 length = part->size;
 204
 205         info.error_type = cpu_to_be32(err_type);
 206         info.seq_num = cpu_to_be32(error_log_cnt);
 207
 208         tmp_index = part->index;
 209
 210         rc = ppc_md.nvram_write((char *)&info, sizeof(struct err_log_info),
 211                                 &tmp_index);
 212         if (rc <= 0) {
 213                 pr_err("%s: Failed nvram_write (%d)\n", __func__, rc);
 214                 return rc;
 215         }
 216
 217         rc = ppc_md.nvram_write(buff, length, &tmp_index);
 218         if (rc <= 0) {
 219                 pr_err("%s: Failed nvram_write (%d)\n", __func__, rc);
 220                 return rc;
 221         }
 222
 223         return 0;
 224 }
 225
 226 /* nvram_read_partition
 227  *
 228  * Reads nvram partition for at most 'length'
 229  */
 230 int nvram_read_partition(struct nvram_os_partition *part, char *buff,
 231                          int length, unsigned int *err_type,
 232                          unsigned int *error_log_cnt)
 233 {
 234         int rc;
 235         loff_t tmp_index;
 236         struct err_log_info info;
 237
 238         if (part->index == -1)
 239                 return -1;
 240
 241         if (length > part->size)
 242                 length = part->size;
 243
 244         tmp_index = part->index;
 245
 246         if (part->os_partition) {
 247                 rc = ppc_md.nvram_read((char *)&info,
 248                                         sizeof(struct err_log_info),
 249                                         &tmp_index);
 250                 if (rc <= 0) {
 251                         pr_err("%s: Failed nvram_read (%d)\n", __func__, rc);
 252                         return rc;
 253                 }
 254         }
 255
 256         rc = ppc_md.nvram_read(buff, length, &tmp_index);
 257         if (rc <= 0) {
 258                 pr_err("%s: Failed nvram_read (%d)\n", __func__, rc);
 259                 return rc;
 260         }
 261
 262         if (part->os_partition) {
 263                 *error_log_cnt = be32_to_cpu(info.seq_num);
 264                 *err_type = be32_to_cpu(info.error_type);
 265         }
 266
 267         return 0;
 268 }
 269
 270 /* nvram_init_os_partition
 271  *
 272  * This sets up a partition with an "OS" signature.
 273  *
 274  * The general strategy is the following:
 275  * 1.) If a partition with the indicated name already exists...
 276  *      - If it's large enough, use it.
 277  *      - Otherwise, recycle it and keep going.
 278  * 2.) Search for a free partition that is large enough.
 279  * 3.) If there's not a free partition large enough, recycle any obsolete
 280  * OS partitions and try again.
 281  * 4.) Will first try getting a chunk that will satisfy the requested size.
 282  * 5.) If a chunk of the requested size cannot be allocated, then try finding
 283  * a chunk that will satisfy the minum needed.
 284  *
 285  * Returns 0 on success, else -1.
 286  */
 287 int __init nvram_init_os_partition(struct nvram_os_partition *part)
 288 {
 289         loff_t p;
 290         int size;
 291
 292         /* Look for ours */
 293         p = nvram_find_partition(part->name, NVRAM_SIG_OS, &size);
 294
 295         /* Found one but too small, remove it */
 296         if (p && size < part->min_size) {
 297                 pr_info("nvram: Found too small %s partition,"
 298                                         " removing it...\n", part->name);
 299                 nvram_remove_partition(part->name, NVRAM_SIG_OS, NULL);
 300                 p = 0;
 301         }
 302
 303         /* Create one if we didn't find */
 304         if (!p) {
 305                 p = nvram_create_partition(part->name, NVRAM_SIG_OS,
 306                                         part->req_size, part->min_size);
 307                 if (p == -ENOSPC) {
 308                         pr_info("nvram: No room to create %s partition, "
 309                                 "deleting any obsolete OS partitions...\n",
 310                                 part->name);
 311                         nvram_remove_partition(NULL, NVRAM_SIG_OS,
 312                                         nvram_os_partitions);
 313                         p = nvram_create_partition(part->name, NVRAM_SIG_OS,
 314                                         part->req_size, part->min_size);
 315                 }
 316         }
 317
 318         if (p <= 0) {
 319                 pr_err("nvram: Failed to find or create %s"
 320                        " partition, err %d\n", part->name, (int)p);
 321                 return -1;
 322         }
 323
 324         part->index = p;
 325         part->size = nvram_get_partition_size(p) - sizeof(struct err_log_info);
 326
 327         return 0;
 328 }
 329
 330 /* Derived from logfs_compress() */
 331 static int nvram_compress(const void *in, void *out, size_t inlen,
 332                                                         size_t outlen)
 333 {
 334         int err, ret;
 335
 336         ret = -EIO;
 337         err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
 338                                                 MEM_LEVEL, Z_DEFAULT_STRATEGY);
 339         if (err != Z_OK)
 340                 goto error;
 341
 342         stream.next_in = in;
 343         stream.avail_in = inlen;
 344         stream.total_in = 0;
 345         stream.next_out = out;
 346         stream.avail_out = outlen;
 347         stream.total_out = 0;
 348
 349         err = zlib_deflate(&stream, Z_FINISH);
 350         if (err != Z_STREAM_END)
 351                 goto error;
 352
 353         err = zlib_deflateEnd(&stream);
 354         if (err != Z_OK)
 355                 goto error;
 356
 357         if (stream.total_out >= stream.total_in)
 358                 goto error;
 359
 360         ret = stream.total_out;
 361 error:
 362         return ret;
 363 }
 364
 365 /* Compress the text from big_oops_buf into oops_buf. */
 366 static int zip_oops(size_t text_len)
 367 {
 368         struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
 369         int zipped_len = nvram_compress(big_oops_buf, oops_data, text_len,
 370                                                                 oops_data_sz);
 371         if (zipped_len < 0) {
 372                 pr_err("nvram: compression failed; returned %d\n", zipped_len);
 373                 pr_err("nvram: logging uncompressed oops/panic report\n");
 374                 return -1;
 375         }
 376         oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
 377         oops_hdr->report_length = cpu_to_be16(zipped_len);
 378         oops_hdr->timestamp = cpu_to_be64(ktime_get_real_seconds());
 379         return 0;
 380 }
 381
 382 #ifdef CONFIG_PSTORE
 383 static int nvram_pstore_open(struct pstore_info *psi)
 384 {
 385         /* Reset the iterator to start reading partitions again */
 386         read_type = -1;
 387         return 0;
 388 }
 389
 390 /**
 391  * nvram_pstore_write - pstore write callback for nvram
 392  * @type:               Type of message logged
 393  * @reason:             reason behind dump (oops/panic)
 394  * @id:                 identifier to indicate the write performed
 395  * @part:               pstore writes data to registered buffer in parts,
 396  *                      part number will indicate the same.
 397  * @count:              Indicates oops count
 398  * @compressed:         Flag to indicate the log is compressed
 399  * @size:               number of bytes written to the registered buffer
 400  * @psi:                registered pstore_info structure
 401  *
 402  * Called by pstore_dump() when an oops or panic report is logged in the
 403  * printk buffer.
 404  * Returns 0 on successful write.
 405  */
 406 static int nvram_pstore_write(enum pstore_type_id type,
 407                                 enum kmsg_dump_reason reason,
 408                                 u64 *id, unsigned int part, int count,
 409                                 bool compressed, size_t size,
 410                                 struct pstore_info *psi)
 411 {
 412         int rc;
 413         unsigned int err_type = ERR_TYPE_KERNEL_PANIC;
 414         struct oops_log_info *oops_hdr = (struct oops_log_info *) oops_buf;
 415
 416         /* part 1 has the recent messages from printk buffer */
 417         if (part > 1 || (type != PSTORE_TYPE_DMESG))
 418                 return -1;
 419
 420         if (clobbering_unread_rtas_event())
 421                 return -1;
 422
 423         oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
 424         oops_hdr->report_length = cpu_to_be16(size);
 425         oops_hdr->timestamp = cpu_to_be64(ktime_get_real_seconds());
 426
 427         if (compressed)
 428                 err_type = ERR_TYPE_KERNEL_PANIC_GZ;
 429
 430         rc = nvram_write_os_partition(&oops_log_partition, oops_buf,
 431                 (int) (sizeof(*oops_hdr) + size), err_type, count);
 432
 433         if (rc != 0)
 434                 return rc;
 435
 436         *id = part;
 437         return 0;
 438 }
 439
 440 /*
 441  * Reads the oops/panic report, rtas, of-config and common partition.
 442  * Returns the length of the data we read from each partition.
 443  * Returns 0 if we've been called before.
 444  */
 445 static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
 446                                 int *count, struct timespec *time, char **buf,
 447                                 bool *compressed, ssize_t *ecc_notice_size,
 448                                 struct pstore_info *psi)
 449 {
 450         struct oops_log_info *oops_hdr;
 451         unsigned int err_type, id_no, size = 0;
 452         struct nvram_os_partition *part = NULL;
 453         char *buff = NULL;
 454         int sig = 0;
 455         loff_t p;
 456
 457         read_type++;
 458
 459         switch (nvram_type_ids[read_type]) {
 460         case PSTORE_TYPE_DMESG:
 461                 part = &oops_log_partition;
 462                 *type = PSTORE_TYPE_DMESG;
 463                 break;
 464         case PSTORE_TYPE_PPC_COMMON:
 465                 sig = NVRAM_SIG_SYS;
 466                 part = &common_partition;
 467                 *type = PSTORE_TYPE_PPC_COMMON;
 468                 *id = PSTORE_TYPE_PPC_COMMON;
 469                 time->tv_sec = 0;
 470                 time->tv_nsec = 0;
 471                 break;
 472 #ifdef CONFIG_PPC_PSERIES
 473         case PSTORE_TYPE_PPC_RTAS:
 474                 part = &rtas_log_partition;
 475                 *type = PSTORE_TYPE_PPC_RTAS;
 476                 time->tv_sec = last_rtas_event;
 477                 time->tv_nsec = 0;
 478                 break;
 479         case PSTORE_TYPE_PPC_OF:
 480                 sig = NVRAM_SIG_OF;
 481                 part = &of_config_partition;
 482                 *type = PSTORE_TYPE_PPC_OF;
 483                 *id = PSTORE_TYPE_PPC_OF;
 484                 time->tv_sec = 0;
 485                 time->tv_nsec = 0;
 486                 break;
 487 #endif
 488 #ifdef CONFIG_PPC_POWERNV
 489         case PSTORE_TYPE_PPC_OPAL:
 490                 sig = NVRAM_SIG_FW;
 491                 part = &skiboot_partition;
 492                 *type = PSTORE_TYPE_PPC_OPAL;
 493                 *id = PSTORE_TYPE_PPC_OPAL;
 494                 time->tv_sec = 0;
 495                 time->tv_nsec = 0;
 496                 break;
 497 #endif
 498         default:
 499                 return 0;
 500         }
 501
 502         if (!part->os_partition) {
 503                 p = nvram_find_partition(part->name, sig, &size);
 504                 if (p <= 0) {
 505                         pr_err("nvram: Failed to find partition %s, "
 506                                 "err %d\n", part->name, (int)p);
 507                         return 0;
 508                 }
 509                 part->index = p;
 510                 part->size = size;
 511         }
 512
 513         buff = kmalloc(part->size, GFP_KERNEL);
 514
 515         if (!buff)
 516                 return -ENOMEM;
 517
 518         if (nvram_read_partition(part, buff, part->size, &err_type, &id_no)) {
 519                 kfree(buff);
 520                 return 0;
 521         }
 522
 523         *count = 0;
 524
 525         if (part->os_partition)
 526                 *id = id_no;
 527
 528         if (nvram_type_ids[read_type] == PSTORE_TYPE_DMESG) {
 529                 size_t length, hdr_size;
 530
 531                 oops_hdr = (struct oops_log_info *)buff;
 532                 if (be16_to_cpu(oops_hdr->version) < OOPS_HDR_VERSION) {
 533                         /* Old format oops header had 2-byte record size */
 534                         hdr_size = sizeof(u16);
 535                         length = be16_to_cpu(oops_hdr->version);
 536                         time->tv_sec = 0;
 537                         time->tv_nsec = 0;
 538                 } else {
 539                         hdr_size = sizeof(*oops_hdr);
 540                         length = be16_to_cpu(oops_hdr->report_length);
 541                         time->tv_sec = be64_to_cpu(oops_hdr->timestamp);
 542                         time->tv_nsec = 0;
 543                 }
 544                 *buf = kmemdup(buff + hdr_size, length, GFP_KERNEL);
 545                 kfree(buff);
 546                 if (*buf == NULL)
 547                         return -ENOMEM;
 548
 549                 *ecc_notice_size = 0;
 550                 if (err_type == ERR_TYPE_KERNEL_PANIC_GZ)
 551                         *compressed = true;
 552                 else
 553                         *compressed = false;
 554                 return length;
 555         }
 556
 557         *buf = buff;
 558         return part->size;
 559 }
 560
 561 static struct pstore_info nvram_pstore_info = {
 562         .owner = THIS_MODULE,
 563         .name = "nvram",
 564         .flags = PSTORE_FLAGS_DMESG,
 565         .open = nvram_pstore_open,
 566         .read = nvram_pstore_read,
 567         .write = nvram_pstore_write,
 568 };
 569
 570 static int nvram_pstore_init(void)
 571 {
 572         int rc = 0;
 573
 574         if (machine_is(pseries)) {
 575                 nvram_type_ids[2] = PSTORE_TYPE_PPC_RTAS;
 576                 nvram_type_ids[3] = PSTORE_TYPE_PPC_OF;
 577         } else
 578                 nvram_type_ids[2] = PSTORE_TYPE_PPC_OPAL;
 579
 580         nvram_pstore_info.buf = oops_data;
 581         nvram_pstore_info.bufsize = oops_data_sz;
 582
 583         spin_lock_init(&nvram_pstore_info.buf_lock);
 584
 585         rc = pstore_register(&nvram_pstore_info);
 586         if (rc && (rc != -EPERM))
 587                 /* Print error only when pstore.backend == nvram */
 588                 pr_err("nvram: pstore_register() failed, returned %d. "
 589                                 "Defaults to kmsg_dump\n", rc);
 590
 591         return rc;
 592 }
 593 #else
 594 static int nvram_pstore_init(void)
 595 {
 596         return -1;
 597 }
 598 #endif
 599
 600 void __init nvram_init_oops_partition(int rtas_partition_exists)
 601 {
 602         int rc;
 603
 604         rc = nvram_init_os_partition(&oops_log_partition);
 605         if (rc != 0) {
 606 #ifdef CONFIG_PPC_PSERIES
 607                 if (!rtas_partition_exists) {
 608                         pr_err("nvram: Failed to initialize oops partition!");
 609                         return;
 610                 }
 611                 pr_notice("nvram: Using %s partition to log both"
 612                         " RTAS errors and oops/panic reports\n",
 613                         rtas_log_partition.name);
 614                 memcpy(&oops_log_partition, &rtas_log_partition,
 615                                                 sizeof(rtas_log_partition));
 616 #else
 617                 pr_err("nvram: Failed to initialize oops partition!");
 618                 return;
 619 #endif
 620         }
 621         oops_buf = kmalloc(oops_log_partition.size, GFP_KERNEL);
 622         if (!oops_buf) {
 623                 pr_err("nvram: No memory for %s partition\n",
 624                                                 oops_log_partition.name);
 625                 return;
 626         }
 627         oops_data = oops_buf + sizeof(struct oops_log_info);
 628         oops_data_sz = oops_log_partition.size - sizeof(struct oops_log_info);
 629
 630         rc = nvram_pstore_init();
 631
 632         if (!rc)
 633                 return;
 634
 635         /*
 636          * Figure compression (preceded by elimination of each line's <n>
 637          * severity prefix) will reduce the oops/panic report to at most
 638          * 45% of its original size.
 639          */
 640         big_oops_buf_sz = (oops_data_sz * 100) / 45;
 641         big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
 642         if (big_oops_buf) {
 643                 stream.workspace =  kmalloc(zlib_deflate_workspacesize(
 644                                         WINDOW_BITS, MEM_LEVEL), GFP_KERNEL);
 645                 if (!stream.workspace) {
 646                         pr_err("nvram: No memory for compression workspace; "
 647                                 "skipping compression of %s partition data\n",
 648                                 oops_log_partition.name);
 649                         kfree(big_oops_buf);
 650                         big_oops_buf = NULL;
 651                 }
 652         } else {
 653                 pr_err("No memory for uncompressed %s data; "
 654                         "skipping compression\n", oops_log_partition.name);
 655                 stream.workspace = NULL;
 656         }
 657
 658         rc = kmsg_dump_register(&nvram_kmsg_dumper);
 659         if (rc != 0) {
 660                 pr_err("nvram: kmsg_dump_register() failed; returned %d\n", rc);
 661                 kfree(oops_buf);
 662                 kfree(big_oops_buf);
 663                 kfree(stream.workspace);
 664         }
 665 }
 666
 667 /*
 668  * This is our kmsg_dump callback, called after an oops or panic report
 669  * has been written to the printk buffer.  We want to capture as much
 670  * of the printk buffer as possible.  First, capture as much as we can
 671  * that we think will compress sufficiently to fit in the lnx,oops-log
 672  * partition.  If that's too much, go back and capture uncompressed text.
 673  */
 674 static void oops_to_nvram(struct kmsg_dumper *dumper,
 675                           enum kmsg_dump_reason reason)
 676 {
 677         struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
 678         static unsigned int oops_count = 0;
 679         static bool panicking = false;
 680         static DEFINE_SPINLOCK(lock);
 681         unsigned long flags;
 682         size_t text_len;
 683         unsigned int err_type = ERR_TYPE_KERNEL_PANIC_GZ;
 684         int rc = -1;
 685
 686         switch (reason) {
 687         case KMSG_DUMP_RESTART:
 688         case KMSG_DUMP_HALT:
 689         case KMSG_DUMP_POWEROFF:
 690                 /* These are almost always orderly shutdowns. */
 691                 return;
 692         case KMSG_DUMP_OOPS:
 693                 break;
 694         case KMSG_DUMP_PANIC:
 695                 panicking = true;
 696                 break;
 697         case KMSG_DUMP_EMERG:
 698                 if (panicking)
 699                         /* Panic report already captured. */
 700                         return;
 701                 break;
 702         default:
 703                 pr_err("%s: ignoring unrecognized KMSG_DUMP_* reason %d\n",
 704                        __func__, (int) reason);
 705                 return;
 706         }
 707
 708         if (clobbering_unread_rtas_event())
 709                 return;
 710
 711         if (!spin_trylock_irqsave(&lock, flags))
 712                 return;
 713
 714         if (big_oops_buf) {
 715                 kmsg_dump_get_buffer(dumper, false,
 716                                      big_oops_buf, big_oops_buf_sz, &text_len);
 717                 rc = zip_oops(text_len);
 718         }
 719         if (rc != 0) {
 720                 kmsg_dump_rewind(dumper);
 721                 kmsg_dump_get_buffer(dumper, false,
 722                                      oops_data, oops_data_sz, &text_len);
 723                 err_type = ERR_TYPE_KERNEL_PANIC;
 724                 oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
 725                 oops_hdr->report_length = cpu_to_be16(text_len);
 726                 oops_hdr->timestamp = cpu_to_be64(ktime_get_real_seconds());
 727         }
 728
 729         (void) nvram_write_os_partition(&oops_log_partition, oops_buf,
 730                 (int) (sizeof(*oops_hdr) + text_len), err_type,
 731                 ++oops_count);
 732
 733         spin_unlock_irqrestore(&lock, flags);
 734 }
 735
 736 static loff_t dev_nvram_llseek(struct file *file, loff_t offset, int origin)
 737 {
 738         if (ppc_md.nvram_size == NULL)
 739                 return -ENODEV;
 740         return generic_file_llseek_size(file, offset, origin, MAX_LFS_FILESIZE,
 741                                         ppc_md.nvram_size());
 742 }
 743
 744
 745 static ssize_t dev_nvram_read(struct file *file, char __user *buf,
 746                           size_t count, loff_t *ppos)
 747 {
 748         ssize_t ret;
 749         char *tmp = NULL;
 750         ssize_t size;
 751
 752         if (!ppc_md.nvram_size) {
 753                 ret = -ENODEV;
 754                 goto out;
 755         }
 756
 757         size = ppc_md.nvram_size();
 758         if (size < 0) {
 759                 ret = size;
 760                 goto out;
 761         }
 762
 763         if (*ppos >= size) {
 764                 ret = 0;
 765                 goto out;
 766         }
 767
 768         count = min_t(size_t, count, size - *ppos);
 769         count = min(count, PAGE_SIZE);
 770
 771         tmp = kmalloc(count, GFP_KERNEL);
 772         if (!tmp) {
 773                 ret = -ENOMEM;
 774                 goto out;
 775         }
 776
 777         ret = ppc_md.nvram_read(tmp, count, ppos);
 778         if (ret <= 0)
 779                 goto out;
 780
 781         if (copy_to_user(buf, tmp, ret))
 782                 ret = -EFAULT;
 783
 784 out:
 785         kfree(tmp);
 786         return ret;
 787
 788 }
 789
 790 static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
 791                           size_t count, loff_t *ppos)
 792 {
 793         ssize_t ret;
 794         char *tmp = NULL;
 795         ssize_t size;
 796
 797         ret = -ENODEV;
 798         if (!ppc_md.nvram_size)
 799                 goto out;
 800
 801         ret = 0;
 802         size = ppc_md.nvram_size();
 803         if (*ppos >= size || size < 0)
 804                 goto out;
 805
 806         count = min_t(size_t, count, size - *ppos);
 807         count = min(count, PAGE_SIZE);
 808
 809         ret = -ENOMEM;
 810         tmp = kmalloc(count, GFP_KERNEL);
 811         if (!tmp)
 812                 goto out;
 813
 814         ret = -EFAULT;
 815         if (copy_from_user(tmp, buf, count))
 816                 goto out;
 817
 818         ret = ppc_md.nvram_write(tmp, count, ppos);
 819
 820 out:
 821         kfree(tmp);
 822         return ret;
 823
 824 }
 825
 826 static long dev_nvram_ioctl(struct file *file, unsigned int cmd,
 827                             unsigned long arg)
 828 {
 829         switch(cmd) {
 830 #ifdef CONFIG_PPC_PMAC
 831         case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
 832                 printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
 833         case IOC_NVRAM_GET_OFFSET: {
 834                 int part, offset;
 835
 836                 if (!machine_is(powermac))
 837                         return -EINVAL;
 838                 if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
 839                         return -EFAULT;
 840                 if (part < pmac_nvram_OF || part > pmac_nvram_NR)
 841                         return -EINVAL;
 842                 offset = pmac_get_partition(part);
 843                 if (offset < 0)
 844                         return offset;
 845                 if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
 846                         return -EFAULT;
 847                 return 0;
 848         }
 849 #endif /* CONFIG_PPC_PMAC */
 850         default:
 851                 return -EINVAL;
 852         }
 853 }
 854
 855 static const struct file_operations nvram_fops = {
 856         .owner          = THIS_MODULE,
 857         .llseek         = dev_nvram_llseek,
 858         .read           = dev_nvram_read,
 859         .write          = dev_nvram_write,
 860         .unlocked_ioctl = dev_nvram_ioctl,
 861 };
 862
 863 static struct miscdevice nvram_dev = {
 864         NVRAM_MINOR,
 865         "nvram",
 866         &nvram_fops
 867 };
 868
 869
 870 #ifdef DEBUG_NVRAM
 871 static void __init nvram_print_partitions(char * label)
 872 {
 873         struct nvram_partition * tmp_part;
 874
 875         printk(KERN_WARNING "--------%s---------\n", label);
 876         printk(KERN_WARNING "indx\t\tsig\tchks\tlen\tname\n");
 877         list_for_each_entry(tmp_part, &nvram_partitions, partition) {
 878                 printk(KERN_WARNING "%4d    \t%02x\t%02x\t%d\t%12.12s\n",
 879                        tmp_part->index, tmp_part->header.signature,
 880                        tmp_part->header.checksum, tmp_part->header.length,
 881                        tmp_part->header.name);
 882         }
 883 }
 884 #endif
 885
 886
 887 static int __init nvram_write_header(struct nvram_partition * part)
 888 {
 889         loff_t tmp_index;
 890         int rc;
 891         struct nvram_header phead;
 892
 893         memcpy(&phead, &part->header, NVRAM_HEADER_LEN);
 894         phead.length = cpu_to_be16(phead.length);
 895
 896         tmp_index = part->index;
 897         rc = ppc_md.nvram_write((char *)&phead, NVRAM_HEADER_LEN, &tmp_index);
 898
 899         return rc;
 900 }
 901
 902
 903 static unsigned char __init nvram_checksum(struct nvram_header *p)
 904 {
 905         unsigned int c_sum, c_sum2;
 906         unsigned short *sp = (unsigned short *)p->name; /* assume 6 shorts */
 907         c_sum = p->signature + p->length + sp[0] + sp[1] + sp[2] + sp[3] + sp[4] + sp[5];
 908
 909         /* The sum may have spilled into the 3rd byte.  Fold it back. */
 910         c_sum = ((c_sum & 0xffff) + (c_sum >> 16)) & 0xffff;
 911         /* The sum cannot exceed 2 bytes.  Fold it into a checksum */
 912         c_sum2 = (c_sum >> 8) + (c_sum << 8);
 913         c_sum = ((c_sum + c_sum2) >> 8) & 0xff;
 914         return c_sum;
 915 }
 916
 917 /*
 918  * Per the criteria passed via nvram_remove_partition(), should this
 919  * partition be removed?  1=remove, 0=keep
 920  */
 921 static int nvram_can_remove_partition(struct nvram_partition *part,
 922                 const char *name, int sig, const char *exceptions[])
 923 {
 924         if (part->header.signature != sig)
 925                 return 0;
 926         if (name) {
 927                 if (strncmp(name, part->header.name, 12))
 928                         return 0;
 929         } else if (exceptions) {
 930                 const char **except;
 931                 for (except = exceptions; *except; except++) {
 932                         if (!strncmp(*except, part->header.name, 12))
 933                                 return 0;
 934                 }
 935         }
 936         return 1;
 937 }
 938
 939 /**
 940  * nvram_remove_partition - Remove one or more partitions in nvram
 941  * @name: name of the partition to remove, or NULL for a
 942  *        signature only match
 943  * @sig: signature of the partition(s) to remove
 944  * @exceptions: When removing all partitions with a matching signature,
 945  *        leave these alone.
 946  */
 947
 948 int __init nvram_remove_partition(const char *name, int sig,
 949                                                 const char *exceptions[])
 950 {
 951         struct nvram_partition *part, *prev, *tmp;
 952         int rc;
 953
 954         list_for_each_entry(part, &nvram_partitions, partition) {
 955                 if (!nvram_can_remove_partition(part, name, sig, exceptions))
 956                         continue;
 957
 958                 /* Make partition a free partition */
 959                 part->header.signature = NVRAM_SIG_FREE;
 960                 memset(part->header.name, 'w', 12);
 961                 part->header.checksum = nvram_checksum(&part->header);
 962                 rc = nvram_write_header(part);
 963                 if (rc <= 0) {
 964                         printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
 965                         return rc;
 966                 }
 967         }
 968
 969         /* Merge contiguous ones */
 970         prev = NULL;
 971         list_for_each_entry_safe(part, tmp, &nvram_partitions, partition) {
 972                 if (part->header.signature != NVRAM_SIG_FREE) {
 973                         prev = NULL;
 974                         continue;
 975                 }
 976                 if (prev) {
 977                         prev->header.length += part->header.length;
 978                         prev->header.checksum = nvram_checksum(&prev->header);
 979                         rc = nvram_write_header(prev);
 980                         if (rc <= 0) {
 981                                 printk(KERN_ERR "nvram_remove_partition: nvram_write failed (%d)\n", rc);
 982                                 return rc;
 983                         }
 984                         list_del(&part->partition);
 985                         kfree(part);
 986                 } else
 987                         prev = part;
 988         }
 989
 990         return 0;
 991 }
 992
 993 /**
 994  * nvram_create_partition - Create a partition in nvram
 995  * @name: name of the partition to create
 996  * @sig: signature of the partition to create
 997  * @req_size: size of data to allocate in bytes
 998  * @min_size: minimum acceptable size (0 means req_size)
 999  *
1000  * Returns a negative error code or a positive nvram index
1001  * of the beginning of the data area of the newly created
1002  * partition. If you provided a min_size smaller than req_size
1003  * you need to query for the actual size yourself after the
1004  * call using nvram_partition_get_size().
1005  */
1006 loff_t __init nvram_create_partition(const char *name, int sig,
1007                                      int req_size, int min_size)
1008 {
1009         struct nvram_partition *part;
1010         struct nvram_partition *new_part;
1011         struct nvram_partition *free_part = NULL;
1012         static char nv_init_vals[16];
1013         loff_t tmp_index;
1014         long size = 0;
1015         int rc;
1016
1017         /* Convert sizes from bytes to blocks */
1018         req_size = _ALIGN_UP(req_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
1019         min_size = _ALIGN_UP(min_size, NVRAM_BLOCK_LEN) / NVRAM_BLOCK_LEN;
1020
1021         /* If no minimum size specified, make it the same as the
1022          * requested size
1023          */
1024         if (min_size == 0)
1025                 min_size = req_size;
1026         if (min_size > req_size)
1027                 return -EINVAL;
1028
1029         /* Now add one block to each for the header */
1030         req_size += 1;
1031         min_size += 1;
1032
1033         /* Find a free partition that will give us the maximum needed size
1034            If can't find one that will give us the minimum size needed */
1035         list_for_each_entry(part, &nvram_partitions, partition) {
1036                 if (part->header.signature != NVRAM_SIG_FREE)
1037                         continue;
1038
1039                 if (part->header.length >= req_size) {
1040                         size = req_size;
1041                         free_part = part;
1042                         break;
1043                 }
1044                 if (part->header.length > size &&
1045                     part->header.length >= min_size) {
1046                         size = part->header.length;
1047                         free_part = part;
1048                 }
1049         }
1050         if (!size)
1051                 return -ENOSPC;
1052
1053         /* Create our OS partition */
1054         new_part = kmalloc(sizeof(*new_part), GFP_KERNEL);
1055         if (!new_part) {
1056                 pr_err("%s: kmalloc failed\n", __func__);
1057                 return -ENOMEM;
1058         }
1059
1060         new_part->index = free_part->index;
1061         new_part->header.signature = sig;
1062         new_part->header.length = size;
1063         strncpy(new_part->header.name, name, 12);
1064         new_part->header.checksum = nvram_checksum(&new_part->header);
1065
1066         rc = nvram_write_header(new_part);
1067         if (rc <= 0) {
1068                 pr_err("%s: nvram_write_header failed (%d)\n", __func__, rc);
1069                 kfree(new_part);
1070                 return rc;
1071         }
1072         list_add_tail(&new_part->partition, &free_part->partition);
1073
1074         /* Adjust or remove the partition we stole the space from */
1075         if (free_part->header.length > size) {
1076                 free_part->index += size * NVRAM_BLOCK_LEN;
1077                 free_part->header.length -= size;
1078                 free_part->header.checksum = nvram_checksum(&free_part->header);
1079                 rc = nvram_write_header(free_part);
1080                 if (rc <= 0) {
1081                         pr_err("%s: nvram_write_header failed (%d)\n",
1082                                __func__, rc);
1083                         return rc;
1084                 }
1085         } else {
1086                 list_del(&free_part->partition);
1087                 kfree(free_part);
1088         }
1089
1090         /* Clear the new partition */
1091         for (tmp_index = new_part->index + NVRAM_HEADER_LEN;
1092              tmp_index <  ((size - 1) * NVRAM_BLOCK_LEN);
1093              tmp_index += NVRAM_BLOCK_LEN) {
1094                 rc = ppc_md.nvram_write(nv_init_vals, NVRAM_BLOCK_LEN, &tmp_index);
1095                 if (rc <= 0) {
1096                         pr_err("%s: nvram_write failed (%d)\n",
1097                                __func__, rc);
1098                         return rc;
1099                 }
1100         }
1101
1102         return new_part->index + NVRAM_HEADER_LEN;
1103 }
1104
1105 /**
1106  * nvram_get_partition_size - Get the data size of an nvram partition
1107  * @data_index: This is the offset of the start of the data of
1108  *              the partition. The same value that is returned by
1109  *              nvram_create_partition().
1110  */
1111 int nvram_get_partition_size(loff_t data_index)
1112 {
1113         struct nvram_partition *part;
1114
1115         list_for_each_entry(part, &nvram_partitions, partition) {
1116                 if (part->index + NVRAM_HEADER_LEN == data_index)
1117                         return (part->header.length - 1) * NVRAM_BLOCK_LEN;
1118         }
1119         return -1;
1120 }
1121
1122
1123 /**
1124  * nvram_find_partition - Find an nvram partition by signature and name
1125  * @name: Name of the partition or NULL for any name
1126  * @sig: Signature to test against
1127  * @out_size: if non-NULL, returns the size of the data part of the partition
1128  */
1129 loff_t nvram_find_partition(const char *name, int sig, int *out_size)
1130 {
1131         struct nvram_partition *p;
1132
1133         list_for_each_entry(p, &nvram_partitions, partition) {
1134                 if (p->header.signature == sig &&
1135                     (!name || !strncmp(p->header.name, name, 12))) {
1136                         if (out_size)
1137                                 *out_size = (p->header.length - 1) *
1138                                         NVRAM_BLOCK_LEN;
1139                         return p->index + NVRAM_HEADER_LEN;
1140                 }
1141         }
1142         return 0;
1143 }
1144
1145 int __init nvram_scan_partitions(void)
1146 {
1147         loff_t cur_index = 0;
1148         struct nvram_header phead;
1149         struct nvram_partition * tmp_part;
1150         unsigned char c_sum;
1151         char * header;
1152         int total_size;
1153         int err;
1154
1155         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
1156                 return -ENODEV;
1157         total_size = ppc_md.nvram_size();
1158
1159         header = kmalloc(NVRAM_HEADER_LEN, GFP_KERNEL);
1160         if (!header) {
1161                 printk(KERN_ERR "nvram_scan_partitions: Failed kmalloc\n");
1162                 return -ENOMEM;
1163         }
1164
1165         while (cur_index < total_size) {
1166
1167                 err = ppc_md.nvram_read(header, NVRAM_HEADER_LEN, &cur_index);
1168                 if (err != NVRAM_HEADER_LEN) {
1169                         printk(KERN_ERR "nvram_scan_partitions: Error parsing "
1170                                "nvram partitions\n");
1171                         goto out;
1172                 }
1173
1174                 cur_index -= NVRAM_HEADER_LEN; /* nvram_read will advance us */
1175
1176                 memcpy(&phead, header, NVRAM_HEADER_LEN);
1177
1178                 phead.length = be16_to_cpu(phead.length);
1179
1180                 err = 0;
1181                 c_sum = nvram_checksum(&phead);
1182                 if (c_sum != phead.checksum) {
1183                         printk(KERN_WARNING "WARNING: nvram partition checksum"
1184                                " was %02x, should be %02x!\n",
1185                                phead.checksum, c_sum);
1186                         printk(KERN_WARNING "Terminating nvram partition scan\n");
1187                         goto out;
1188                 }
1189                 if (!phead.length) {
1190                         printk(KERN_WARNING "WARNING: nvram corruption "
1191                                "detected: 0-length partition\n");
1192                         goto out;
1193                 }
1194                 tmp_part = kmalloc(sizeof(struct nvram_partition), GFP_KERNEL);
1195                 err = -ENOMEM;
1196                 if (!tmp_part) {
1197                         printk(KERN_ERR "nvram_scan_partitions: kmalloc failed\n");
1198                         goto out;
1199                 }
1200
1201                 memcpy(&tmp_part->header, &phead, NVRAM_HEADER_LEN);
1202                 tmp_part->index = cur_index;
1203                 list_add_tail(&tmp_part->partition, &nvram_partitions);
1204
1205                 cur_index += phead.length * NVRAM_BLOCK_LEN;
1206         }
1207         err = 0;
1208
1209 #ifdef DEBUG_NVRAM
1210         nvram_print_partitions("NVRAM Partitions");
1211 #endif
1212
1213  out:
1214         kfree(header);
1215         return err;
1216 }
1217
1218 static int __init nvram_init(void)
1219 {
1220         int rc;
1221
1222         BUILD_BUG_ON(NVRAM_BLOCK_LEN != 16);
1223
1224         if (ppc_md.nvram_size == NULL || ppc_md.nvram_size() <= 0)
1225                 return  -ENODEV;
1226
1227         rc = misc_register(&nvram_dev);
1228         if (rc != 0) {
1229                 printk(KERN_ERR "nvram_init: failed to register device\n");
1230                 return rc;
1231         }
1232
1233         return rc;
1234 }
1235 device_initcall(nvram_init);