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/ctype.h>
  22 #include <linux/zlib.h>
  23 #include <asm/uaccess.h>
  24 #include <asm/nvram.h>
  25 #include <asm/rtas.h>
  26 #include <asm/prom.h>
  27 #include <asm/machdep.h>
  28
  29 /* Max bytes to read/write in one go */
  30 #define NVRW_CNT 0x20
  31
  32 /*
  33  * Set oops header version to distingush between old and new format header.
  34  * lnx,oops-log partition max size is 4000, header version > 4000 will
  35  * help in identifying new header.
  36  */
  37 #define OOPS_HDR_VERSION 5000
  38
  39 static unsigned int nvram_size;
  40 static int nvram_fetch, nvram_store;
  41 static char nvram_buf[NVRW_CNT];        /* assume this is in the first 4GB */
  42 static DEFINE_SPINLOCK(nvram_lock);
  43
  44 struct err_log_info {
  45         int error_type;
  46         unsigned int seq_num;
  47 };
  48
  49 struct nvram_os_partition {
  50         const char *name;
  51         int req_size;   /* desired size, in bytes */
  52         int min_size;   /* minimum acceptable size (0 means req_size) */
  53         long size;      /* size of data portion (excluding err_log_info) */
  54         long index;     /* offset of data portion of partition */
  55 };
  56
  57 static struct nvram_os_partition rtas_log_partition = {
  58         .name = "ibm,rtas-log",
  59         .req_size = 2079,
  60         .min_size = 1055,
  61         .index = -1
  62 };
  63
  64 static struct nvram_os_partition oops_log_partition = {
  65         .name = "lnx,oops-log",
  66         .req_size = 4000,
  67         .min_size = 2000,
  68         .index = -1
  69 };
  70
  71 static const char *pseries_nvram_os_partitions[] = {
  72         "ibm,rtas-log",
  73         "lnx,oops-log",
  74         NULL
  75 };
  76
  77 struct oops_log_info {
  78         u16 version;
  79         u16 report_length;
  80         u64 timestamp;
  81 } __attribute__((packed));
  82
  83 static void oops_to_nvram(struct kmsg_dumper *dumper,
  84                           enum kmsg_dump_reason reason);
  85
  86 static struct kmsg_dumper nvram_kmsg_dumper = {
  87         .dump = oops_to_nvram
  88 };
  89
  90 /* See clobbering_unread_rtas_event() */
  91 #define NVRAM_RTAS_READ_TIMEOUT 5               /* seconds */
  92 static unsigned long last_unread_rtas_event;    /* timestamp */
  93
  94 /*
  95  * For capturing and compressing an oops or panic report...
  96
  97  * big_oops_buf[] holds the uncompressed text we're capturing.
  98  *
  99  * oops_buf[] holds the compressed text, preceded by a oops header.
 100  * oops header has u16 holding the version of oops header (to differentiate
 101  * between old and new format header) followed by u16 holding the length of
 102  * the compressed* text (*Or uncompressed, if compression fails.) and u64
 103  * holding the timestamp. oops_buf[] gets written to NVRAM.
 104  *
 105  * oops_log_info points to the header. oops_data points to the compressed text.
 106  *
 107  * +- oops_buf
 108  * |                                   +- oops_data
 109  * v                                   v
 110  * +-----------+-----------+-----------+------------------------+
 111  * | version   | length    | timestamp | text                   |
 112  * | (2 bytes) | (2 bytes) | (8 bytes) | (oops_data_sz bytes)   |
 113  * +-----------+-----------+-----------+------------------------+
 114  * ^
 115  * +- oops_log_info
 116  *
 117  * We preallocate these buffers during init to avoid kmalloc during oops/panic.
 118  */
 119 static size_t big_oops_buf_sz;
 120 static char *big_oops_buf, *oops_buf;
 121 static char *oops_data;
 122 static size_t oops_data_sz;
 123
 124 /* Compression parameters */
 125 #define COMPR_LEVEL 6
 126 #define WINDOW_BITS 12
 127 #define MEM_LEVEL 4
 128 static struct z_stream_s stream;
 129
 130 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
 131 {
 132         unsigned int i;
 133         unsigned long len;
 134         int done;
 135         unsigned long flags;
 136         char *p = buf;
 137
 138
 139         if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE)
 140                 return -ENODEV;
 141
 142         if (*index >= nvram_size)
 143                 return 0;
 144
 145         i = *index;
 146         if (i + count > nvram_size)
 147                 count = nvram_size - i;
 148
 149         spin_lock_irqsave(&nvram_lock, flags);
 150
 151         for (; count != 0; count -= len) {
 152                 len = count;
 153                 if (len > NVRW_CNT)
 154                         len = NVRW_CNT;
 155
 156                 if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf),
 157                                len) != 0) || len != done) {
 158                         spin_unlock_irqrestore(&nvram_lock, flags);
 159                         return -EIO;
 160                 }
 161
 162                 memcpy(p, nvram_buf, len);
 163
 164                 p += len;
 165                 i += len;
 166         }
 167
 168         spin_unlock_irqrestore(&nvram_lock, flags);
 169
 170         *index = i;
 171         return p - buf;
 172 }
 173
 174 static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index)
 175 {
 176         unsigned int i;
 177         unsigned long len;
 178         int done;
 179         unsigned long flags;
 180         const char *p = buf;
 181
 182         if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE)
 183                 return -ENODEV;
 184
 185         if (*index >= nvram_size)
 186                 return 0;
 187
 188         i = *index;
 189         if (i + count > nvram_size)
 190                 count = nvram_size - i;
 191
 192         spin_lock_irqsave(&nvram_lock, flags);
 193
 194         for (; count != 0; count -= len) {
 195                 len = count;
 196                 if (len > NVRW_CNT)
 197                         len = NVRW_CNT;
 198
 199                 memcpy(nvram_buf, p, len);
 200
 201                 if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf),
 202                                len) != 0) || len != done) {
 203                         spin_unlock_irqrestore(&nvram_lock, flags);
 204                         return -EIO;
 205                 }
 206
 207                 p += len;
 208                 i += len;
 209         }
 210         spin_unlock_irqrestore(&nvram_lock, flags);
 211
 212         *index = i;
 213         return p - buf;
 214 }
 215
 216 static ssize_t pSeries_nvram_get_size(void)
 217 {
 218         return nvram_size ? nvram_size : -ENODEV;
 219 }
 220
 221
 222 /* nvram_write_os_partition, nvram_write_error_log
 223  *
 224  * We need to buffer the error logs into nvram to ensure that we have
 225  * the failure information to decode.  If we have a severe error there
 226  * is no way to guarantee that the OS or the machine is in a state to
 227  * get back to user land and write the error to disk.  For example if
 228  * the SCSI device driver causes a Machine Check by writing to a bad
 229  * IO address, there is no way of guaranteeing that the device driver
 230  * is in any state that is would also be able to write the error data
 231  * captured to disk, thus we buffer it in NVRAM for analysis on the
 232  * next boot.
 233  *
 234  * In NVRAM the partition containing the error log buffer will looks like:
 235  * Header (in bytes):
 236  * +-----------+----------+--------+------------+------------------+
 237  * | signature | checksum | length | name       | data             |
 238  * |0          |1         |2      3|4         15|16        length-1|
 239  * +-----------+----------+--------+------------+------------------+
 240  *
 241  * The 'data' section would look like (in bytes):
 242  * +--------------+------------+-----------------------------------+
 243  * | event_logged | sequence # | error log                         |
 244  * |0            3|4          7|8                  error_log_size-1|
 245  * +--------------+------------+-----------------------------------+
 246  *
 247  * event_logged: 0 if event has not been logged to syslog, 1 if it has
 248  * sequence #: The unique sequence # for each event. (until it wraps)
 249  * error log: The error log from event_scan
 250  */
 251 int nvram_write_os_partition(struct nvram_os_partition *part, char * buff,
 252                 int length, unsigned int err_type, unsigned int error_log_cnt)
 253 {
 254         int rc;
 255         loff_t tmp_index;
 256         struct err_log_info info;
 257
 258         if (part->index == -1) {
 259                 return -ESPIPE;
 260         }
 261
 262         if (length > part->size) {
 263                 length = part->size;
 264         }
 265
 266         info.error_type = err_type;
 267         info.seq_num = error_log_cnt;
 268
 269         tmp_index = part->index;
 270
 271         rc = ppc_md.nvram_write((char *)&info, sizeof(struct err_log_info), &tmp_index);
 272         if (rc <= 0) {
 273                 pr_err("%s: Failed nvram_write (%d)\n", __FUNCTION__, rc);
 274                 return rc;
 275         }
 276
 277         rc = ppc_md.nvram_write(buff, length, &tmp_index);
 278         if (rc <= 0) {
 279                 pr_err("%s: Failed nvram_write (%d)\n", __FUNCTION__, rc);
 280                 return rc;
 281         }
 282
 283         return 0;
 284 }
 285
 286 int nvram_write_error_log(char * buff, int length,
 287                           unsigned int err_type, unsigned int error_log_cnt)
 288 {
 289         int rc = nvram_write_os_partition(&rtas_log_partition, buff, length,
 290                                                 err_type, error_log_cnt);
 291         if (!rc)
 292                 last_unread_rtas_event = get_seconds();
 293         return rc;
 294 }
 295
 296 /* nvram_read_error_log
 297  *
 298  * Reads nvram for error log for at most 'length'
 299  */
 300 int nvram_read_error_log(char * buff, int length,
 301                          unsigned int * err_type, unsigned int * error_log_cnt)
 302 {
 303         int rc;
 304         loff_t tmp_index;
 305         struct err_log_info info;
 306
 307         if (rtas_log_partition.index == -1)
 308                 return -1;
 309
 310         if (length > rtas_log_partition.size)
 311                 length = rtas_log_partition.size;
 312
 313         tmp_index = rtas_log_partition.index;
 314
 315         rc = ppc_md.nvram_read((char *)&info, sizeof(struct err_log_info), &tmp_index);
 316         if (rc <= 0) {
 317                 printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
 318                 return rc;
 319         }
 320
 321         rc = ppc_md.nvram_read(buff, length, &tmp_index);
 322         if (rc <= 0) {
 323                 printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc);
 324                 return rc;
 325         }
 326
 327         *error_log_cnt = info.seq_num;
 328         *err_type = info.error_type;
 329
 330         return 0;
 331 }
 332
 333 /* This doesn't actually zero anything, but it sets the event_logged
 334  * word to tell that this event is safely in syslog.
 335  */
 336 int nvram_clear_error_log(void)
 337 {
 338         loff_t tmp_index;
 339         int clear_word = ERR_FLAG_ALREADY_LOGGED;
 340         int rc;
 341
 342         if (rtas_log_partition.index == -1)
 343                 return -1;
 344
 345         tmp_index = rtas_log_partition.index;
 346
 347         rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index);
 348         if (rc <= 0) {
 349                 printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc);
 350                 return rc;
 351         }
 352         last_unread_rtas_event = 0;
 353
 354         return 0;
 355 }
 356
 357 /* pseries_nvram_init_os_partition
 358  *
 359  * This sets up a partition with an "OS" signature.
 360  *
 361  * The general strategy is the following:
 362  * 1.) If a partition with the indicated name already exists...
 363  *      - If it's large enough, use it.
 364  *      - Otherwise, recycle it and keep going.
 365  * 2.) Search for a free partition that is large enough.
 366  * 3.) If there's not a free partition large enough, recycle any obsolete
 367  * OS partitions and try again.
 368  * 4.) Will first try getting a chunk that will satisfy the requested size.
 369  * 5.) If a chunk of the requested size cannot be allocated, then try finding
 370  * a chunk that will satisfy the minum needed.
 371  *
 372  * Returns 0 on success, else -1.
 373  */
 374 static int __init pseries_nvram_init_os_partition(struct nvram_os_partition
 375                                                                         *part)
 376 {
 377         loff_t p;
 378         int size;
 379
 380         /* Scan nvram for partitions */
 381         nvram_scan_partitions();
 382
 383         /* Look for ours */
 384         p = nvram_find_partition(part->name, NVRAM_SIG_OS, &size);
 385
 386         /* Found one but too small, remove it */
 387         if (p && size < part->min_size) {
 388                 pr_info("nvram: Found too small %s partition,"
 389                                         " removing it...\n", part->name);
 390                 nvram_remove_partition(part->name, NVRAM_SIG_OS, NULL);
 391                 p = 0;
 392         }
 393
 394         /* Create one if we didn't find */
 395         if (!p) {
 396                 p = nvram_create_partition(part->name, NVRAM_SIG_OS,
 397                                         part->req_size, part->min_size);
 398                 if (p == -ENOSPC) {
 399                         pr_info("nvram: No room to create %s partition, "
 400                                 "deleting any obsolete OS partitions...\n",
 401                                 part->name);
 402                         nvram_remove_partition(NULL, NVRAM_SIG_OS,
 403                                                 pseries_nvram_os_partitions);
 404                         p = nvram_create_partition(part->name, NVRAM_SIG_OS,
 405                                         part->req_size, part->min_size);
 406                 }
 407         }
 408
 409         if (p <= 0) {
 410                 pr_err("nvram: Failed to find or create %s"
 411                        " partition, err %d\n", part->name, (int)p);
 412                 return -1;
 413         }
 414
 415         part->index = p;
 416         part->size = nvram_get_partition_size(p) - sizeof(struct err_log_info);
 417
 418         return 0;
 419 }
 420
 421 static void __init nvram_init_oops_partition(int rtas_partition_exists)
 422 {
 423         int rc;
 424
 425         rc = pseries_nvram_init_os_partition(&oops_log_partition);
 426         if (rc != 0) {
 427                 if (!rtas_partition_exists)
 428                         return;
 429                 pr_notice("nvram: Using %s partition to log both"
 430                         " RTAS errors and oops/panic reports\n",
 431                         rtas_log_partition.name);
 432                 memcpy(&oops_log_partition, &rtas_log_partition,
 433                                                 sizeof(rtas_log_partition));
 434         }
 435         oops_buf = kmalloc(oops_log_partition.size, GFP_KERNEL);
 436         if (!oops_buf) {
 437                 pr_err("nvram: No memory for %s partition\n",
 438                                                 oops_log_partition.name);
 439                 return;
 440         }
 441         oops_data = oops_buf + sizeof(struct oops_log_info);
 442         oops_data_sz = oops_log_partition.size - sizeof(struct oops_log_info);
 443
 444         /*
 445          * Figure compression (preceded by elimination of each line's <n>
 446          * severity prefix) will reduce the oops/panic report to at most
 447          * 45% of its original size.
 448          */
 449         big_oops_buf_sz = (oops_data_sz * 100) / 45;
 450         big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
 451         if (big_oops_buf) {
 452                 stream.workspace = kmalloc(zlib_deflate_workspacesize(
 453                                 WINDOW_BITS, MEM_LEVEL), GFP_KERNEL);
 454                 if (!stream.workspace) {
 455                         pr_err("nvram: No memory for compression workspace; "
 456                                 "skipping compression of %s partition data\n",
 457                                 oops_log_partition.name);
 458                         kfree(big_oops_buf);
 459                         big_oops_buf = NULL;
 460                 }
 461         } else {
 462                 pr_err("No memory for uncompressed %s data; "
 463                         "skipping compression\n", oops_log_partition.name);
 464                 stream.workspace = NULL;
 465         }
 466
 467         rc = kmsg_dump_register(&nvram_kmsg_dumper);
 468         if (rc != 0) {
 469                 pr_err("nvram: kmsg_dump_register() failed; returned %d\n", rc);
 470                 kfree(oops_buf);
 471                 kfree(big_oops_buf);
 472                 kfree(stream.workspace);
 473         }
 474 }
 475
 476 static int __init pseries_nvram_init_log_partitions(void)
 477 {
 478         int rc;
 479
 480         rc = pseries_nvram_init_os_partition(&rtas_log_partition);
 481         nvram_init_oops_partition(rc == 0);
 482         return 0;
 483 }
 484 machine_arch_initcall(pseries, pseries_nvram_init_log_partitions);
 485
 486 int __init pSeries_nvram_init(void)
 487 {
 488         struct device_node *nvram;
 489         const unsigned int *nbytes_p;
 490         unsigned int proplen;
 491
 492         nvram = of_find_node_by_type(NULL, "nvram");
 493         if (nvram == NULL)
 494                 return -ENODEV;
 495
 496         nbytes_p = of_get_property(nvram, "#bytes", &proplen);
 497         if (nbytes_p == NULL || proplen != sizeof(unsigned int)) {
 498                 of_node_put(nvram);
 499                 return -EIO;
 500         }
 501
 502         nvram_size = *nbytes_p;
 503
 504         nvram_fetch = rtas_token("nvram-fetch");
 505         nvram_store = rtas_token("nvram-store");
 506         printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
 507         of_node_put(nvram);
 508
 509         ppc_md.nvram_read       = pSeries_nvram_read;
 510         ppc_md.nvram_write      = pSeries_nvram_write;
 511         ppc_md.nvram_size       = pSeries_nvram_get_size;
 512
 513         return 0;
 514 }
 515
 516 /*
 517  * Are we using the ibm,rtas-log for oops/panic reports?  And if so,
 518  * would logging this oops/panic overwrite an RTAS event that rtas_errd
 519  * hasn't had a chance to read and process?  Return 1 if so, else 0.
 520  *
 521  * We assume that if rtas_errd hasn't read the RTAS event in
 522  * NVRAM_RTAS_READ_TIMEOUT seconds, it's probably not going to.
 523  */
 524 static int clobbering_unread_rtas_event(void)
 525 {
 526         return (oops_log_partition.index == rtas_log_partition.index
 527                 && last_unread_rtas_event
 528                 && get_seconds() - last_unread_rtas_event <=
 529                                                 NVRAM_RTAS_READ_TIMEOUT);
 530 }
 531
 532 /* Derived from logfs_compress() */
 533 static int nvram_compress(const void *in, void *out, size_t inlen,
 534                                                         size_t outlen)
 535 {
 536         int err, ret;
 537
 538         ret = -EIO;
 539         err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
 540                                                 MEM_LEVEL, Z_DEFAULT_STRATEGY);
 541         if (err != Z_OK)
 542                 goto error;
 543
 544         stream.next_in = in;
 545         stream.avail_in = inlen;
 546         stream.total_in = 0;
 547         stream.next_out = out;
 548         stream.avail_out = outlen;
 549         stream.total_out = 0;
 550
 551         err = zlib_deflate(&stream, Z_FINISH);
 552         if (err != Z_STREAM_END)
 553                 goto error;
 554
 555         err = zlib_deflateEnd(&stream);
 556         if (err != Z_OK)
 557                 goto error;
 558
 559         if (stream.total_out >= stream.total_in)
 560                 goto error;
 561
 562         ret = stream.total_out;
 563 error:
 564         return ret;
 565 }
 566
 567 /* Compress the text from big_oops_buf into oops_buf. */
 568 static int zip_oops(size_t text_len)
 569 {
 570         struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
 571         int zipped_len = nvram_compress(big_oops_buf, oops_data, text_len,
 572                                                                 oops_data_sz);
 573         if (zipped_len < 0) {
 574                 pr_err("nvram: compression failed; returned %d\n", zipped_len);
 575                 pr_err("nvram: logging uncompressed oops/panic report\n");
 576                 return -1;
 577         }
 578         oops_hdr->version = OOPS_HDR_VERSION;
 579         oops_hdr->report_length = (u16) zipped_len;
 580         oops_hdr->timestamp = get_seconds();
 581         return 0;
 582 }
 583
 584 /*
 585  * This is our kmsg_dump callback, called after an oops or panic report
 586  * has been written to the printk buffer.  We want to capture as much
 587  * of the printk buffer as possible.  First, capture as much as we can
 588  * that we think will compress sufficiently to fit in the lnx,oops-log
 589  * partition.  If that's too much, go back and capture uncompressed text.
 590  */
 591 static void oops_to_nvram(struct kmsg_dumper *dumper,
 592                           enum kmsg_dump_reason reason)
 593 {
 594         struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
 595         static unsigned int oops_count = 0;
 596         static bool panicking = false;
 597         static DEFINE_SPINLOCK(lock);
 598         unsigned long flags;
 599         size_t text_len;
 600         unsigned int err_type = ERR_TYPE_KERNEL_PANIC_GZ;
 601         int rc = -1;
 602
 603         switch (reason) {
 604         case KMSG_DUMP_RESTART:
 605         case KMSG_DUMP_HALT:
 606         case KMSG_DUMP_POWEROFF:
 607                 /* These are almost always orderly shutdowns. */
 608                 return;
 609         case KMSG_DUMP_OOPS:
 610                 break;
 611         case KMSG_DUMP_PANIC:
 612                 panicking = true;
 613                 break;
 614         case KMSG_DUMP_EMERG:
 615                 if (panicking)
 616                         /* Panic report already captured. */
 617                         return;
 618                 break;
 619         default:
 620                 pr_err("%s: ignoring unrecognized KMSG_DUMP_* reason %d\n",
 621                                                 __FUNCTION__, (int) reason);
 622                 return;
 623         }
 624
 625         if (clobbering_unread_rtas_event())
 626                 return;
 627
 628         if (!spin_trylock_irqsave(&lock, flags))
 629                 return;
 630
 631         if (big_oops_buf) {
 632                 kmsg_dump_get_buffer(dumper, false,
 633                                      big_oops_buf, big_oops_buf_sz, &text_len);
 634                 rc = zip_oops(text_len);
 635         }
 636         if (rc != 0) {
 637                 kmsg_dump_rewind(dumper);
 638                 kmsg_dump_get_buffer(dumper, false,
 639                                      oops_data, oops_data_sz, &text_len);
 640                 err_type = ERR_TYPE_KERNEL_PANIC;
 641                 oops_hdr->version = OOPS_HDR_VERSION;
 642                 oops_hdr->report_length = (u16) text_len;
 643                 oops_hdr->timestamp = get_seconds();
 644         }
 645
 646         (void) nvram_write_os_partition(&oops_log_partition, oops_buf,
 647                 (int) (sizeof(*oops_hdr) + oops_hdr->report_length), err_type,
 648                 ++oops_count);
 649
 650         spin_unlock_irqrestore(&lock, flags);
 651 }