arch/powerpc/platforms/pseries/nvram.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
  14
  15 #include <linux/types.h>
  16 #include <linux/errno.h>
  17 #include <linux/init.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/slab.h>
  20 #include <linux/kmsg_dump.h>
  21 #include <linux/pstore.h>
  22 #include <linux/ctype.h>
  23 #include <linux/zlib.h>
  24 #include <asm/uaccess.h>
  25 #include <asm/nvram.h>
  26 #include <asm/rtas.h>
  27 #include <asm/prom.h>
  28 #include <asm/machdep.h>
  29
  30 /* Max bytes to read/write in one go */
  31 #define NVRW_CNT 0x20
  32
  33 /*
  34  * Set oops header version to distinguish between old and new format header.
  35  * lnx,oops-log partition max size is 4000, header version > 4000 will
  36  * help in identifying new header.
  37  */
  38 #define OOPS_HDR_VERSION 5000
  39
  40 static unsigned int nvram_size;
  41 static int nvram_fetch, nvram_store;
  42 static char nvram_buf[NVRW_CNT];        /* assume this is in the first 4GB */
  43 static DEFINE_SPINLOCK(nvram_lock);
  44
  45 struct err_log_info {
  46         __be32 error_type;
  47         __be32 seq_num;
  48 };
  49
  50 struct nvram_os_partition {
  51         const char *name;
  52         int req_size;   /* desired size, in bytes */
  53         int min_size;   /* minimum acceptable size (0 means req_size) */
  54         long size;      /* size of data portion (excluding err_log_info) */
  55         long index;     /* offset of data portion of partition */
  56         bool os_partition; /* partition initialized by OS, not FW */
  57 };
  58
  59 static struct nvram_os_partition rtas_log_partition = {
  60         .name = "ibm,rtas-log",
  61         .req_size = 2079,
  62         .min_size = 1055,
  63         .index = -1,
  64         .os_partition = true
  65 };
  66
  67 static struct nvram_os_partition oops_log_partition = {
  68         .name = "lnx,oops-log",
  69         .req_size = 4000,
  70         .min_size = 2000,
  71         .index = -1,
  72         .os_partition = true
  73 };
  74
  75 static const char *pseries_nvram_os_partitions[] = {
  76         "ibm,rtas-log",
  77         "lnx,oops-log",
  78         NULL
  79 };
  80
  81 struct oops_log_info {
  82         __be16 version;
  83         __be16 report_length;
  84         __be64 timestamp;
  85 } __attribute__((packed));
  86
  87 static void oops_to_nvram(struct kmsg_dumper *dumper,
  88                           enum kmsg_dump_reason reason);
  89
  90 static struct kmsg_dumper nvram_kmsg_dumper = {
  91         .dump = oops_to_nvram
  92 };
  93
  94 /* See clobbering_unread_rtas_event() */
  95 #define NVRAM_RTAS_READ_TIMEOUT 5               /* seconds */
  96 static unsigned long last_unread_rtas_event;    /* timestamp */
  97
  98 /*
  99  * For capturing and compressing an oops or panic report...
 100
 101  * big_oops_buf[] holds the uncompressed text we're capturing.
 102  *
 103  * oops_buf[] holds the compressed text, preceded by a oops header.
 104  * oops header has u16 holding the version of oops header (to differentiate
 105  * between old and new format header) followed by u16 holding the length of
 106  * the compressed* text (*Or uncompressed, if compression fails.) and u64
 107  * holding the timestamp. oops_buf[] gets written to NVRAM.
 108  *
 109  * oops_log_info points to the header. oops_data points to the compressed text.
 110  *
 111  * +- oops_buf
 112  * |                                   +- oops_data
 113  * v                                   v
 114  * +-----------+-----------+-----------+------------------------+
 115  * | version   | length    | timestamp | text                   |
 116  * | (2 bytes) | (2 bytes) | (8 bytes) | (oops_data_sz bytes)   |
 117  * +-----------+-----------+-----------+------------------------+
 118  * ^
 119  * +- oops_log_info
 120  *
 121  * We preallocate these buffers during init to avoid kmalloc during oops/panic.
 122  */
 123 static size_t big_oops_buf_sz;
 124 static char *big_oops_buf, *oops_buf;
 125 static char *oops_data;
 126 static size_t oops_data_sz;
 127
 128 /* Compression parameters */
 129 #define COMPR_LEVEL 6
 130 #define WINDOW_BITS 12
 131 #define MEM_LEVEL 4
 132 static struct z_stream_s stream;
 133
 134 #ifdef CONFIG_PSTORE
 135 static struct nvram_os_partition of_config_partition = {
 136         .name = "of-config",
 137         .index = -1,
 138         .os_partition = false
 139 };
 140
 141 static struct nvram_os_partition common_partition = {
 142         .name = "common",
 143         .index = -1,
 144         .os_partition = false
 145 };
 146
 147 static enum pstore_type_id nvram_type_ids[] = {
 148         PSTORE_TYPE_DMESG,
 149         PSTORE_TYPE_PPC_RTAS,
 150         PSTORE_TYPE_PPC_OF,
 151         PSTORE_TYPE_PPC_COMMON,
 152         -1
 153 };
 154 static int read_type;
 155 static unsigned long last_rtas_event;
 156 #endif
 157
 158 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
 159 {
 160         unsigned int i;
 161         unsigned long len;
 162         int done;
 163         unsigned long flags;
 164         char *p = buf;
 165
 166
 167         if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE)
 168                 return -ENODEV;
 169
 170         if (*index >= nvram_size)
 171                 return 0;
 172
 173         i = *index;
 174         if (i + count > nvram_size)
 175                 count = nvram_size - i;
 176
 177         spin_lock_irqsave(&nvram_lock, flags);
 178
 179         for (; count != 0; count -= len) {
 180                 len = count;
 181                 if (len > NVRW_CNT)
 182                         len = NVRW_CNT;
 183
 184                 if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf),
 185                                len) != 0) || len != done) {
 186                         spin_unlock_irqrestore(&nvram_lock, flags);
 187                         return -EIO;
 188                 }
 189
 190                 memcpy(p, nvram_buf, len);
 191
 192                 p += len;
 193                 i += len;
 194         }
 195
 196         spin_unlock_irqrestore(&nvram_lock, flags);
 197
 198         *index = i;
 199         return p - buf;
 200 }
 201
 202 static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index)
 203 {
 204         unsigned int i;
 205         unsigned long len;
 206         int done;
 207         unsigned long flags;
 208         const char *p = buf;
 209
 210         if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE)
 211                 return -ENODEV;
 212
 213         if (*index >= nvram_size)
 214                 return 0;
 215
 216         i = *index;
 217         if (i + count > nvram_size)
 218                 count = nvram_size - i;
 219
 220         spin_lock_irqsave(&nvram_lock, flags);
 221
 222         for (; count != 0; count -= len) {
 223                 len = count;
 224                 if (len > NVRW_CNT)
 225                         len = NVRW_CNT;
 226
 227                 memcpy(nvram_buf, p, len);
 228
 229                 if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf),
 230                                len) != 0) || len != done) {
 231                         spin_unlock_irqrestore(&nvram_lock, flags);
 232                         return -EIO;
 233                 }
 234
 235                 p += len;
 236                 i += len;
 237         }
 238         spin_unlock_irqrestore(&nvram_lock, flags);
 239
 240         *index = i;
 241         return p - buf;
 242 }
 243
 244 static ssize_t pSeries_nvram_get_size(void)
 245 {
 246         return nvram_size ? nvram_size : -ENODEV;
 247 }
 248
 249
 250 /* nvram_write_os_partition, nvram_write_error_log
 251  *
 252  * We need to buffer the error logs into nvram to ensure that we have
 253  * the failure information to decode.  If we have a severe error there
 254  * is no way to guarantee that the OS or the machine is in a state to
 255  * get back to user land and write the error to disk.  For example if
 256  * the SCSI device driver causes a Machine Check by writing to a bad
 257  * IO address, there is no way of guaranteeing that the device driver
 258  * is in any state that is would also be able to write the error data
 259  * captured to disk, thus we buffer it in NVRAM for analysis on the
 260  * next boot.
 261  *
 262  * In NVRAM the partition containing the error log buffer will looks like:
 263  * Header (in bytes):
 264  * +-----------+----------+--------+------------+------------------+
 265  * | signature | checksum | length | name       | data             |
 266  * |0          |1         |2      3|4         15|16        length-1|
 267  * +-----------+----------+--------+------------+------------------+
 268  *
 269  * The 'data' section would look like (in bytes):
 270  * +--------------+------------+-----------------------------------+
 271  * | event_logged | sequence # | error log                         |
 272  * |0            3|4          7|8                  error_log_size-1|
 273  * +--------------+------------+-----------------------------------+
 274  *
 275  * event_logged: 0 if event has not been logged to syslog, 1 if it has
 276  * sequence #: The unique sequence # for each event. (until it wraps)
 277  * error log: The error log from event_scan
 278  */
 279 static int nvram_write_os_partition(struct nvram_os_partition *part,
 280                                     char *buff, int length,
 281                                     unsigned int err_type,
 282                                     unsigned int error_log_cnt)
 283 {
 284         int rc;
 285         loff_t tmp_index;
 286         struct err_log_info info;
 287
 288         if (part->index == -1) {
 289                 return -ESPIPE;
 290         }
 291
 292         if (length > part->size) {
 293                 length = part->size;
 294         }
 295
 296         info.error_type = cpu_to_be32(err_type);
 297         info.seq_num = cpu_to_be32(error_log_cnt);
 298
 299         tmp_index = part->index;
 300
 301         rc = ppc_md.nvram_write((char *)&info, sizeof(struct err_log_info), &tmp_index);
 302         if (rc <= 0) {
 303                 pr_err("%s: Failed nvram_write (%d)\n", __func__, rc);
 304                 return rc;
 305         }
 306
 307         rc = ppc_md.nvram_write(buff, length, &tmp_index);
 308         if (rc <= 0) {
 309                 pr_err("%s: Failed nvram_write (%d)\n", __func__, rc);
 310                 return rc;
 311         }
 312
 313         return 0;
 314 }
 315
 316 int nvram_write_error_log(char * buff, int length,
 317                           unsigned int err_type, unsigned int error_log_cnt)
 318 {
 319         int rc = nvram_write_os_partition(&rtas_log_partition, buff, length,
 320                                                 err_type, error_log_cnt);
 321         if (!rc) {
 322                 last_unread_rtas_event = get_seconds();
 323 #ifdef CONFIG_PSTORE
 324                 last_rtas_event = get_seconds();
 325 #endif
 326         }
 327
 328         return rc;
 329 }
 330
 331 /* nvram_read_partition
 332  *
 333  * Reads nvram partition for at most 'length'
 334  */
 335 static int nvram_read_partition(struct nvram_os_partition *part, char *buff,
 336                                 int length, unsigned int *err_type,
 337                                 unsigned int *error_log_cnt)
 338 {
 339         int rc;
 340         loff_t tmp_index;
 341         struct err_log_info info;
 342
 343         if (part->index == -1)
 344                 return -1;
 345
 346         if (length > part->size)
 347                 length = part->size;
 348
 349         tmp_index = part->index;
 350
 351         if (part->os_partition) {
 352                 rc = ppc_md.nvram_read((char *)&info,
 353                                         sizeof(struct err_log_info),
 354                                         &tmp_index);
 355                 if (rc <= 0) {
 356                         pr_err("%s: Failed nvram_read (%d)\n", __func__, rc);
 357                         return rc;
 358                 }
 359         }
 360
 361         rc = ppc_md.nvram_read(buff, length, &tmp_index);
 362         if (rc <= 0) {
 363                 pr_err("%s: Failed nvram_read (%d)\n", __func__, rc);
 364                 return rc;
 365         }
 366
 367         if (part->os_partition) {
 368                 *error_log_cnt = be32_to_cpu(info.seq_num);
 369                 *err_type = be32_to_cpu(info.error_type);
 370         }
 371
 372         return 0;
 373 }
 374
 375 /* nvram_read_error_log
 376  *
 377  * Reads nvram for error log for at most 'length'
 378  */
 379 int nvram_read_error_log(char *buff, int length,
 380                         unsigned int *err_type, unsigned int *error_log_cnt)
 381 {
 382         return nvram_read_partition(&rtas_log_partition, buff, length,
 383                                                 err_type, error_log_cnt);
 384 }
 385
 386 /* This doesn't actually zero anything, but it sets the event_logged
 387  * word to tell that this event is safely in syslog.
 388  */
 389 int nvram_clear_error_log(void)
 390 {
 391         loff_t tmp_index;
 392         int clear_word = ERR_FLAG_ALREADY_LOGGED;
 393         int rc;
 394
 395         if (rtas_log_partition.index == -1)
 396                 return -1;
 397
 398         tmp_index = rtas_log_partition.index;
 399
 400         rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
 401         if (rc <= 0) {
 402                 printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
 403                 return rc;
 404         }
 405         last_unread_rtas_event = 0;
 406
 407         return 0;
 408 }
 409
 410 /* pseries_nvram_init_os_partition
 411  *
 412  * This sets up a partition with an "OS" signature.
 413  *
 414  * The general strategy is the following:
 415  * 1.) If a partition with the indicated name already exists...
 416  *      - If it's large enough, use it.
 417  *      - Otherwise, recycle it and keep going.
 418  * 2.) Search for a free partition that is large enough.
 419  * 3.) If there's not a free partition large enough, recycle any obsolete
 420  * OS partitions and try again.
 421  * 4.) Will first try getting a chunk that will satisfy the requested size.
 422  * 5.) If a chunk of the requested size cannot be allocated, then try finding
 423  * a chunk that will satisfy the minum needed.
 424  *
 425  * Returns 0 on success, else -1.
 426  */
 427 static int __init pseries_nvram_init_os_partition(struct nvram_os_partition
 428                                                                         *part)
 429 {
 430         loff_t p;
 431         int size;
 432
 433         /* Look for ours */
 434         p = nvram_find_partition(part->name, NVRAM_SIG_OS, &size);
 435
 436         /* Found one but too small, remove it */
 437         if (p && size < part->min_size) {
 438                 pr_info("nvram: Found too small %s partition,"
 439                                         " removing it...\n", part->name);
 440                 nvram_remove_partition(part->name, NVRAM_SIG_OS, NULL);
 441                 p = 0;
 442         }
 443
 444         /* Create one if we didn't find */
 445         if (!p) {
 446                 p = nvram_create_partition(part->name, NVRAM_SIG_OS,
 447                                         part->req_size, part->min_size);
 448                 if (p == -ENOSPC) {
 449                         pr_info("nvram: No room to create %s partition, "
 450                                 "deleting any obsolete OS partitions...\n",
 451                                 part->name);
 452                         nvram_remove_partition(NULL, NVRAM_SIG_OS,
 453                                                 pseries_nvram_os_partitions);
 454                         p = nvram_create_partition(part->name, NVRAM_SIG_OS,
 455                                         part->req_size, part->min_size);
 456                 }
 457         }
 458
 459         if (p <= 0) {
 460                 pr_err("nvram: Failed to find or create %s"
 461                        " partition, err %d\n", part->name, (int)p);
 462                 return -1;
 463         }
 464
 465         part->index = p;
 466         part->size = nvram_get_partition_size(p) - sizeof(struct err_log_info);
 467
 468         return 0;
 469 }
 470
 471 /*
 472  * Are we using the ibm,rtas-log for oops/panic reports?  And if so,
 473  * would logging this oops/panic overwrite an RTAS event that rtas_errd
 474  * hasn't had a chance to read and process?  Return 1 if so, else 0.
 475  *
 476  * We assume that if rtas_errd hasn't read the RTAS event in
 477  * NVRAM_RTAS_READ_TIMEOUT seconds, it's probably not going to.
 478  */
 479 static int clobbering_unread_rtas_event(void)
 480 {
 481         return (oops_log_partition.index == rtas_log_partition.index
 482                 && last_unread_rtas_event
 483                 && get_seconds() - last_unread_rtas_event <=
 484                                                 NVRAM_RTAS_READ_TIMEOUT);
 485 }
 486
 487 /* Derived from logfs_compress() */
 488 static int nvram_compress(const void *in, void *out, size_t inlen,
 489                                                         size_t outlen)
 490 {
 491         int err, ret;
 492
 493         ret = -EIO;
 494         err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
 495                                                 MEM_LEVEL, Z_DEFAULT_STRATEGY);
 496         if (err != Z_OK)
 497                 goto error;
 498
 499         stream.next_in = in;
 500         stream.avail_in = inlen;
 501         stream.total_in = 0;
 502         stream.next_out = out;
 503         stream.avail_out = outlen;
 504         stream.total_out = 0;
 505
 506         err = zlib_deflate(&stream, Z_FINISH);
 507         if (err != Z_STREAM_END)
 508                 goto error;
 509
 510         err = zlib_deflateEnd(&stream);
 511         if (err != Z_OK)
 512                 goto error;
 513
 514         if (stream.total_out >= stream.total_in)
 515                 goto error;
 516
 517         ret = stream.total_out;
 518 error:
 519         return ret;
 520 }
 521
 522 /* Compress the text from big_oops_buf into oops_buf. */
 523 static int zip_oops(size_t text_len)
 524 {
 525         struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
 526         int zipped_len = nvram_compress(big_oops_buf, oops_data, text_len,
 527                                                                 oops_data_sz);
 528         if (zipped_len < 0) {
 529                 pr_err("nvram: compression failed; returned %d\n", zipped_len);
 530                 pr_err("nvram: logging uncompressed oops/panic report\n");
 531                 return -1;
 532         }
 533         oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
 534         oops_hdr->report_length = cpu_to_be16(zipped_len);
 535         oops_hdr->timestamp = cpu_to_be64(get_seconds());
 536         return 0;
 537 }
 538
 539 #ifdef CONFIG_PSTORE
 540 static int nvram_pstore_open(struct pstore_info *psi)
 541 {
 542         /* Reset the iterator to start reading partitions again */
 543         read_type = -1;
 544         return 0;
 545 }
 546
 547 /**
 548  * nvram_pstore_write - pstore write callback for nvram
 549  * @type:               Type of message logged
 550  * @reason:             reason behind dump (oops/panic)
 551  * @id:                 identifier to indicate the write performed
 552  * @part:               pstore writes data to registered buffer in parts,
 553  *                      part number will indicate the same.
 554  * @count:              Indicates oops count
 555  * @compressed:         Flag to indicate the log is compressed
 556  * @size:               number of bytes written to the registered buffer
 557  * @psi:                registered pstore_info structure
 558  *
 559  * Called by pstore_dump() when an oops or panic report is logged in the
 560  * printk buffer.
 561  * Returns 0 on successful write.
 562  */
 563 static int nvram_pstore_write(enum pstore_type_id type,
 564                                 enum kmsg_dump_reason reason,
 565                                 u64 *id, unsigned int part, int count,
 566                                 bool compressed, size_t size,
 567                                 struct pstore_info *psi)
 568 {
 569         int rc;
 570         unsigned int err_type = ERR_TYPE_KERNEL_PANIC;
 571         struct oops_log_info *oops_hdr = (struct oops_log_info *) oops_buf;
 572
 573         /* part 1 has the recent messages from printk buffer */
 574         if (part > 1 || type != PSTORE_TYPE_DMESG ||
 575                                 clobbering_unread_rtas_event())
 576                 return -1;
 577
 578         oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
 579         oops_hdr->report_length = cpu_to_be16(size);
 580         oops_hdr->timestamp = cpu_to_be64(get_seconds());
 581
 582         if (compressed)
 583                 err_type = ERR_TYPE_KERNEL_PANIC_GZ;
 584
 585         rc = nvram_write_os_partition(&oops_log_partition, oops_buf,
 586                 (int) (sizeof(*oops_hdr) + size), err_type, count);
 587
 588         if (rc != 0)
 589                 return rc;
 590
 591         *id = part;
 592         return 0;
 593 }
 594
 595 /*
 596  * Reads the oops/panic report, rtas, of-config and common partition.
 597  * Returns the length of the data we read from each partition.
 598  * Returns 0 if we've been called before.
 599  */
 600 static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
 601                                 int *count, struct timespec *time, char **buf,
 602                                 bool *compressed, struct pstore_info *psi)
 603 {
 604         struct oops_log_info *oops_hdr;
 605         unsigned int err_type, id_no, size = 0;
 606         struct nvram_os_partition *part = NULL;
 607         char *buff = NULL;
 608         int sig = 0;
 609         loff_t p;
 610
 611         read_type++;
 612
 613         switch (nvram_type_ids[read_type]) {
 614         case PSTORE_TYPE_DMESG:
 615                 part = &oops_log_partition;
 616                 *type = PSTORE_TYPE_DMESG;
 617                 break;
 618         case PSTORE_TYPE_PPC_RTAS:
 619                 part = &rtas_log_partition;
 620                 *type = PSTORE_TYPE_PPC_RTAS;
 621                 time->tv_sec = last_rtas_event;
 622                 time->tv_nsec = 0;
 623                 break;
 624         case PSTORE_TYPE_PPC_OF:
 625                 sig = NVRAM_SIG_OF;
 626                 part = &of_config_partition;
 627                 *type = PSTORE_TYPE_PPC_OF;
 628                 *id = PSTORE_TYPE_PPC_OF;
 629                 time->tv_sec = 0;
 630                 time->tv_nsec = 0;
 631                 break;
 632         case PSTORE_TYPE_PPC_COMMON:
 633                 sig = NVRAM_SIG_SYS;
 634                 part = &common_partition;
 635                 *type = PSTORE_TYPE_PPC_COMMON;
 636                 *id = PSTORE_TYPE_PPC_COMMON;
 637                 time->tv_sec = 0;
 638                 time->tv_nsec = 0;
 639                 break;
 640         default:
 641                 return 0;
 642         }
 643
 644         if (!part->os_partition) {
 645                 p = nvram_find_partition(part->name, sig, &size);
 646                 if (p <= 0) {
 647                         pr_err("nvram: Failed to find partition %s, "
 648                                 "err %d\n", part->name, (int)p);
 649                         return 0;
 650                 }
 651                 part->index = p;
 652                 part->size = size;
 653         }
 654
 655         buff = kmalloc(part->size, GFP_KERNEL);
 656
 657         if (!buff)
 658                 return -ENOMEM;
 659
 660         if (nvram_read_partition(part, buff, part->size, &err_type, &id_no)) {
 661                 kfree(buff);
 662                 return 0;
 663         }
 664
 665         *count = 0;
 666
 667         if (part->os_partition)
 668                 *id = id_no;
 669
 670         if (nvram_type_ids[read_type] == PSTORE_TYPE_DMESG) {
 671                 size_t length, hdr_size;
 672
 673                 oops_hdr = (struct oops_log_info *)buff;
 674                 if (be16_to_cpu(oops_hdr->version) < OOPS_HDR_VERSION) {
 675                         /* Old format oops header had 2-byte record size */
 676                         hdr_size = sizeof(u16);
 677                         length = be16_to_cpu(oops_hdr->version);
 678                         time->tv_sec = 0;
 679                         time->tv_nsec = 0;
 680                 } else {
 681                         hdr_size = sizeof(*oops_hdr);
 682                         length = be16_to_cpu(oops_hdr->report_length);
 683                         time->tv_sec = be64_to_cpu(oops_hdr->timestamp);
 684                         time->tv_nsec = 0;
 685                 }
 686                 *buf = kmalloc(length, GFP_KERNEL);
 687                 if (*buf == NULL)
 688                         return -ENOMEM;
 689                 memcpy(*buf, buff + hdr_size, length);
 690                 kfree(buff);
 691
 692                 if (err_type == ERR_TYPE_KERNEL_PANIC_GZ)
 693                         *compressed = true;
 694                 else
 695                         *compressed = false;
 696                 return length;
 697         }
 698
 699         *buf = buff;
 700         return part->size;
 701 }
 702
 703 static struct pstore_info nvram_pstore_info = {
 704         .owner = THIS_MODULE,
 705         .name = "nvram",
 706         .open = nvram_pstore_open,
 707         .read = nvram_pstore_read,
 708         .write = nvram_pstore_write,
 709 };
 710
 711 static int nvram_pstore_init(void)
 712 {
 713         int rc = 0;
 714
 715         nvram_pstore_info.buf = oops_data;
 716         nvram_pstore_info.bufsize = oops_data_sz;
 717
 718         spin_lock_init(&nvram_pstore_info.buf_lock);
 719
 720         rc = pstore_register(&nvram_pstore_info);
 721         if (rc != 0)
 722                 pr_err("nvram: pstore_register() failed, defaults to "
 723                                 "kmsg_dump; returned %d\n", rc);
 724
 725         return rc;
 726 }
 727 #else
 728 static int nvram_pstore_init(void)
 729 {
 730         return -1;
 731 }
 732 #endif
 733
 734 static void __init nvram_init_oops_partition(int rtas_partition_exists)
 735 {
 736         int rc;
 737
 738         rc = pseries_nvram_init_os_partition(&oops_log_partition);
 739         if (rc != 0) {
 740                 if (!rtas_partition_exists)
 741                         return;
 742                 pr_notice("nvram: Using %s partition to log both"
 743                         " RTAS errors and oops/panic reports\n",
 744                         rtas_log_partition.name);
 745                 memcpy(&oops_log_partition, &rtas_log_partition,
 746                                                 sizeof(rtas_log_partition));
 747         }
 748         oops_buf = kmalloc(oops_log_partition.size, GFP_KERNEL);
 749         if (!oops_buf) {
 750                 pr_err("nvram: No memory for %s partition\n",
 751                                                 oops_log_partition.name);
 752                 return;
 753         }
 754         oops_data = oops_buf + sizeof(struct oops_log_info);
 755         oops_data_sz = oops_log_partition.size - sizeof(struct oops_log_info);
 756
 757         rc = nvram_pstore_init();
 758
 759         if (!rc)
 760                 return;
 761
 762         /*
 763          * Figure compression (preceded by elimination of each line's <n>
 764          * severity prefix) will reduce the oops/panic report to at most
 765          * 45% of its original size.
 766          */
 767         big_oops_buf_sz = (oops_data_sz * 100) / 45;
 768         big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
 769         if (big_oops_buf) {
 770                 stream.workspace =  kmalloc(zlib_deflate_workspacesize(
 771                                         WINDOW_BITS, MEM_LEVEL), GFP_KERNEL);
 772                 if (!stream.workspace) {
 773                         pr_err("nvram: No memory for compression workspace; "
 774                                 "skipping compression of %s partition data\n",
 775                                 oops_log_partition.name);
 776                         kfree(big_oops_buf);
 777                         big_oops_buf = NULL;
 778                 }
 779         } else {
 780                 pr_err("No memory for uncompressed %s data; "
 781                         "skipping compression\n", oops_log_partition.name);
 782                 stream.workspace = NULL;
 783         }
 784
 785         rc = kmsg_dump_register(&nvram_kmsg_dumper);
 786         if (rc != 0) {
 787                 pr_err("nvram: kmsg_dump_register() failed; returned %d\n", rc);
 788                 kfree(oops_buf);
 789                 kfree(big_oops_buf);
 790                 kfree(stream.workspace);
 791         }
 792 }
 793
 794 static int __init pseries_nvram_init_log_partitions(void)
 795 {
 796         int rc;
 797
 798         /* Scan nvram for partitions */
 799         nvram_scan_partitions();
 800
 801         rc = pseries_nvram_init_os_partition(&rtas_log_partition);
 802         nvram_init_oops_partition(rc == 0);
 803         return 0;
 804 }
 805 machine_arch_initcall(pseries, pseries_nvram_init_log_partitions);
 806
 807 int __init pSeries_nvram_init(void)
 808 {
 809         struct device_node *nvram;
 810         const __be32 *nbytes_p;
 811         unsigned int proplen;
 812
 813         nvram = of_find_node_by_type(NULL, "nvram");
 814         if (nvram == NULL)
 815                 return -ENODEV;
 816
 817         nbytes_p = of_get_property(nvram, "#bytes", &proplen);
 818         if (nbytes_p == NULL || proplen != sizeof(unsigned int)) {
 819                 of_node_put(nvram);
 820                 return -EIO;
 821         }
 822
 823         nvram_size = be32_to_cpup(nbytes_p);
 824
 825         nvram_fetch = rtas_token("nvram-fetch");
 826         nvram_store = rtas_token("nvram-store");
 827         printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
 828         of_node_put(nvram);
 829
 830         ppc_md.nvram_read       = pSeries_nvram_read;
 831         ppc_md.nvram_write      = pSeries_nvram_write;
 832         ppc_md.nvram_size       = pSeries_nvram_get_size;
 833
 834         return 0;
 835 }
 836
 837
 838 /*
 839  * This is our kmsg_dump callback, called after an oops or panic report
 840  * has been written to the printk buffer.  We want to capture as much
 841  * of the printk buffer as possible.  First, capture as much as we can
 842  * that we think will compress sufficiently to fit in the lnx,oops-log
 843  * partition.  If that's too much, go back and capture uncompressed text.
 844  */
 845 static void oops_to_nvram(struct kmsg_dumper *dumper,
 846                           enum kmsg_dump_reason reason)
 847 {
 848         struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
 849         static unsigned int oops_count = 0;
 850         static bool panicking = false;
 851         static DEFINE_SPINLOCK(lock);
 852         unsigned long flags;
 853         size_t text_len;
 854         unsigned int err_type = ERR_TYPE_KERNEL_PANIC_GZ;
 855         int rc = -1;
 856
 857         switch (reason) {
 858         case KMSG_DUMP_RESTART:
 859         case KMSG_DUMP_HALT:
 860         case KMSG_DUMP_POWEROFF:
 861                 /* These are almost always orderly shutdowns. */
 862                 return;
 863         case KMSG_DUMP_OOPS:
 864                 break;
 865         case KMSG_DUMP_PANIC:
 866                 panicking = true;
 867                 break;
 868         case KMSG_DUMP_EMERG:
 869                 if (panicking)
 870                         /* Panic report already captured. */
 871                         return;
 872                 break;
 873         default:
 874                 pr_err("%s: ignoring unrecognized KMSG_DUMP_* reason %d\n",
 875                        __func__, (int) reason);
 876                 return;
 877         }
 878
 879         if (clobbering_unread_rtas_event())
 880                 return;
 881
 882         if (!spin_trylock_irqsave(&lock, flags))
 883                 return;
 884
 885         if (big_oops_buf) {
 886                 kmsg_dump_get_buffer(dumper, false,
 887                                      big_oops_buf, big_oops_buf_sz, &text_len);
 888                 rc = zip_oops(text_len);
 889         }
 890         if (rc != 0) {
 891                 kmsg_dump_rewind(dumper);
 892                 kmsg_dump_get_buffer(dumper, false,
 893                                      oops_data, oops_data_sz, &text_len);
 894                 err_type = ERR_TYPE_KERNEL_PANIC;
 895                 oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
 896                 oops_hdr->report_length = cpu_to_be16(text_len);
 897                 oops_hdr->timestamp = cpu_to_be64(get_seconds());
 898         }
 899
 900         (void) nvram_write_os_partition(&oops_log_partition, oops_buf,
 901                 (int) (sizeof(*oops_hdr) + text_len), err_type,
 902                 ++oops_count);
 903
 904         spin_unlock_irqrestore(&lock, flags);
 905 }