arch/s390/kernel/debug.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *   S/390 debug facility
   4  *
   5  *    Copyright IBM Corp. 1999, 2012
   6  *
   7  *    Author(s): Michael Holzheu (holzheu@de.ibm.com),
   8  *               Holger Smolinski (Holger.Smolinski@de.ibm.com)
   9  *
  10  *    Bugreports to: <Linux390@de.ibm.com>
  11  */
  12
  13 #define KMSG_COMPONENT "s390dbf"
  14 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  15
  16 #include <linux/stddef.h>
  17 #include <linux/kernel.h>
  18 #include <linux/errno.h>
  19 #include <linux/slab.h>
  20 #include <linux/ctype.h>
  21 #include <linux/string.h>
  22 #include <linux/sysctl.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/export.h>
  25 #include <linux/init.h>
  26 #include <linux/fs.h>
  27 #include <linux/debugfs.h>
  28
  29 #include <asm/debug.h>
  30
  31 #define DEBUG_PROLOG_ENTRY -1
  32
  33 #define ALL_AREAS 0 /* copy all debug areas */
  34 #define NO_AREAS  1 /* copy no debug areas */
  35
  36 /* typedefs */
  37
  38 typedef struct file_private_info {
  39         loff_t offset;                  /* offset of last read in file */
  40         int    act_area;                /* number of last formated area */
  41         int    act_page;                /* act page in given area */
  42         int    act_entry;               /* last formated entry (offset */
  43                                         /* relative to beginning of last */
  44                                         /* formated page) */
  45         size_t act_entry_offset;        /* up to this offset we copied */
  46                                         /* in last read the last formated */
  47                                         /* entry to userland */
  48         char   temp_buf[2048];          /* buffer for output */
  49         debug_info_t *debug_info_org;   /* original debug information */
  50         debug_info_t *debug_info_snap;  /* snapshot of debug information */
  51         struct debug_view *view;        /* used view of debug info */
  52 } file_private_info_t;
  53
  54 typedef struct {
  55         char *string;
  56         /*
  57          * This assumes that all args are converted into longs
  58          * on L/390 this is the case for all types of parameter
  59          * except of floats, and long long (32 bit)
  60          *
  61          */
  62         long args[0];
  63 } debug_sprintf_entry_t;
  64
  65 /* internal function prototyes */
  66
  67 static int debug_init(void);
  68 static ssize_t debug_output(struct file *file, char __user *user_buf,
  69                             size_t user_len, loff_t *offset);
  70 static ssize_t debug_input(struct file *file, const char __user *user_buf,
  71                            size_t user_len, loff_t *offset);
  72 static int debug_open(struct inode *inode, struct file *file);
  73 static int debug_close(struct inode *inode, struct file *file);
  74 static debug_info_t *debug_info_create(const char *name, int pages_per_area,
  75                                        int nr_areas, int buf_size, umode_t mode);
  76 static void debug_info_get(debug_info_t *);
  77 static void debug_info_put(debug_info_t *);
  78 static int debug_prolog_level_fn(debug_info_t *id,
  79                                  struct debug_view *view, char *out_buf);
  80 static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
  81                                 struct file *file, const char __user *user_buf,
  82                                 size_t user_buf_size, loff_t *offset);
  83 static int debug_prolog_pages_fn(debug_info_t *id,
  84                                  struct debug_view *view, char *out_buf);
  85 static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
  86                                 struct file *file, const char __user *user_buf,
  87                                 size_t user_buf_size, loff_t *offset);
  88 static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
  89                                 struct file *file, const char __user *user_buf,
  90                                 size_t user_buf_size, loff_t *offset);
  91 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
  92                                      char *out_buf, const char *in_buf);
  93 static int debug_raw_format_fn(debug_info_t *id,
  94                                struct debug_view *view, char *out_buf,
  95                                const char *in_buf);
  96 static int debug_raw_header_fn(debug_info_t *id, struct debug_view *view,
  97                                int area, debug_entry_t *entry, char *out_buf);
  98
  99 static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
 100                                    char *out_buf, debug_sprintf_entry_t *curr_event);
 101
 102 /* globals */
 103
 104 struct debug_view debug_raw_view = {
 105         "raw",
 106         NULL,
 107         &debug_raw_header_fn,
 108         &debug_raw_format_fn,
 109         NULL,
 110         NULL
 111 };
 112 EXPORT_SYMBOL(debug_raw_view);
 113
 114 struct debug_view debug_hex_ascii_view = {
 115         "hex_ascii",
 116         NULL,
 117         &debug_dflt_header_fn,
 118         &debug_hex_ascii_format_fn,
 119         NULL,
 120         NULL
 121 };
 122 EXPORT_SYMBOL(debug_hex_ascii_view);
 123
 124 static struct debug_view debug_level_view = {
 125         "level",
 126         &debug_prolog_level_fn,
 127         NULL,
 128         NULL,
 129         &debug_input_level_fn,
 130         NULL
 131 };
 132
 133 static struct debug_view debug_pages_view = {
 134         "pages",
 135         &debug_prolog_pages_fn,
 136         NULL,
 137         NULL,
 138         &debug_input_pages_fn,
 139         NULL
 140 };
 141
 142 static struct debug_view debug_flush_view = {
 143         "flush",
 144         NULL,
 145         NULL,
 146         NULL,
 147         &debug_input_flush_fn,
 148         NULL
 149 };
 150
 151 struct debug_view debug_sprintf_view = {
 152         "sprintf",
 153         NULL,
 154         &debug_dflt_header_fn,
 155         (debug_format_proc_t *)&debug_sprintf_format_fn,
 156         NULL,
 157         NULL
 158 };
 159 EXPORT_SYMBOL(debug_sprintf_view);
 160
 161 /* used by dump analysis tools to determine version of debug feature */
 162 static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
 163
 164 /* static globals */
 165
 166 static debug_info_t *debug_area_first;
 167 static debug_info_t *debug_area_last;
 168 static DEFINE_MUTEX(debug_mutex);
 169
 170 static int initialized;
 171 static int debug_critical;
 172
 173 static const struct file_operations debug_file_ops = {
 174         .owner   = THIS_MODULE,
 175         .read    = debug_output,
 176         .write   = debug_input,
 177         .open    = debug_open,
 178         .release = debug_close,
 179         .llseek  = no_llseek,
 180 };
 181
 182 static struct dentry *debug_debugfs_root_entry;
 183
 184 /* functions */
 185
 186 /*
 187  * debug_areas_alloc
 188  * - Debug areas are implemented as a threedimensonal array:
 189  *   areas[areanumber][pagenumber][pageoffset]
 190  */
 191
 192 static debug_entry_t ***debug_areas_alloc(int pages_per_area, int nr_areas)
 193 {
 194         debug_entry_t ***areas;
 195         int i, j;
 196
 197         areas = kmalloc_array(nr_areas, sizeof(debug_entry_t **), GFP_KERNEL);
 198         if (!areas)
 199                 goto fail_malloc_areas;
 200         for (i = 0; i < nr_areas; i++) {
 201                 /* GFP_NOWARN to avoid user triggerable WARN, we handle fails */
 202                 areas[i] = kmalloc_array(pages_per_area,
 203                                          sizeof(debug_entry_t *),
 204                                          GFP_KERNEL | __GFP_NOWARN);
 205                 if (!areas[i])
 206                         goto fail_malloc_areas2;
 207                 for (j = 0; j < pages_per_area; j++) {
 208                         areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
 209                         if (!areas[i][j]) {
 210                                 for (j--; j >= 0 ; j--)
 211                                         kfree(areas[i][j]);
 212                                 kfree(areas[i]);
 213                                 goto fail_malloc_areas2;
 214                         }
 215                 }
 216         }
 217         return areas;
 218
 219 fail_malloc_areas2:
 220         for (i--; i >= 0; i--) {
 221                 for (j = 0; j < pages_per_area; j++)
 222                         kfree(areas[i][j]);
 223                 kfree(areas[i]);
 224         }
 225         kfree(areas);
 226 fail_malloc_areas:
 227         return NULL;
 228 }
 229
 230 /*
 231  * debug_info_alloc
 232  * - alloc new debug-info
 233  */
 234 static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,
 235                                       int nr_areas, int buf_size, int level,
 236                                       int mode)
 237 {
 238         debug_info_t *rc;
 239
 240         /* alloc everything */
 241         rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
 242         if (!rc)
 243                 goto fail_malloc_rc;
 244         rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
 245         if (!rc->active_entries)
 246                 goto fail_malloc_active_entries;
 247         rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
 248         if (!rc->active_pages)
 249                 goto fail_malloc_active_pages;
 250         if ((mode == ALL_AREAS) && (pages_per_area != 0)) {
 251                 rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
 252                 if (!rc->areas)
 253                         goto fail_malloc_areas;
 254         } else {
 255                 rc->areas = NULL;
 256         }
 257
 258         /* initialize members */
 259         spin_lock_init(&rc->lock);
 260         rc->pages_per_area = pages_per_area;
 261         rc->nr_areas       = nr_areas;
 262         rc->active_area    = 0;
 263         rc->level          = level;
 264         rc->buf_size       = buf_size;
 265         rc->entry_size     = sizeof(debug_entry_t) + buf_size;
 266         strlcpy(rc->name, name, sizeof(rc->name));
 267         memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
 268         memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
 269         refcount_set(&(rc->ref_count), 0);
 270
 271         return rc;
 272
 273 fail_malloc_areas:
 274         kfree(rc->active_pages);
 275 fail_malloc_active_pages:
 276         kfree(rc->active_entries);
 277 fail_malloc_active_entries:
 278         kfree(rc);
 279 fail_malloc_rc:
 280         return NULL;
 281 }
 282
 283 /*
 284  * debug_areas_free
 285  * - free all debug areas
 286  */
 287 static void debug_areas_free(debug_info_t *db_info)
 288 {
 289         int i, j;
 290
 291         if (!db_info->areas)
 292                 return;
 293         for (i = 0; i < db_info->nr_areas; i++) {
 294                 for (j = 0; j < db_info->pages_per_area; j++)
 295                         kfree(db_info->areas[i][j]);
 296                 kfree(db_info->areas[i]);
 297         }
 298         kfree(db_info->areas);
 299         db_info->areas = NULL;
 300 }
 301
 302 /*
 303  * debug_info_free
 304  * - free memory debug-info
 305  */
 306 static void debug_info_free(debug_info_t *db_info)
 307 {
 308         debug_areas_free(db_info);
 309         kfree(db_info->active_entries);
 310         kfree(db_info->active_pages);
 311         kfree(db_info);
 312 }
 313
 314 /*
 315  * debug_info_create
 316  * - create new debug-info
 317  */
 318
 319 static debug_info_t *debug_info_create(const char *name, int pages_per_area,
 320                                        int nr_areas, int buf_size, umode_t mode)
 321 {
 322         debug_info_t *rc;
 323
 324         rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
 325                               DEBUG_DEFAULT_LEVEL, ALL_AREAS);
 326         if (!rc)
 327                 goto out;
 328
 329         rc->mode = mode & ~S_IFMT;
 330
 331         /* create root directory */
 332         rc->debugfs_root_entry = debugfs_create_dir(rc->name,
 333                                                     debug_debugfs_root_entry);
 334
 335         /* append new element to linked list */
 336         if (!debug_area_first) {
 337                 /* first element in list */
 338                 debug_area_first = rc;
 339                 rc->prev = NULL;
 340         } else {
 341                 /* append element to end of list */
 342                 debug_area_last->next = rc;
 343                 rc->prev = debug_area_last;
 344         }
 345         debug_area_last = rc;
 346         rc->next = NULL;
 347
 348         refcount_set(&rc->ref_count, 1);
 349 out:
 350         return rc;
 351 }
 352
 353 /*
 354  * debug_info_copy
 355  * - copy debug-info
 356  */
 357 static debug_info_t *debug_info_copy(debug_info_t *in, int mode)
 358 {
 359         unsigned long flags;
 360         debug_info_t *rc;
 361         int i, j;
 362
 363         /* get a consistent copy of the debug areas */
 364         do {
 365                 rc = debug_info_alloc(in->name, in->pages_per_area,
 366                         in->nr_areas, in->buf_size, in->level, mode);
 367                 spin_lock_irqsave(&in->lock, flags);
 368                 if (!rc)
 369                         goto out;
 370                 /* has something changed in the meantime ? */
 371                 if ((rc->pages_per_area == in->pages_per_area) &&
 372                     (rc->nr_areas == in->nr_areas)) {
 373                         break;
 374                 }
 375                 spin_unlock_irqrestore(&in->lock, flags);
 376                 debug_info_free(rc);
 377         } while (1);
 378
 379         if (mode == NO_AREAS)
 380                 goto out;
 381
 382         for (i = 0; i < in->nr_areas; i++) {
 383                 for (j = 0; j < in->pages_per_area; j++)
 384                         memcpy(rc->areas[i][j], in->areas[i][j], PAGE_SIZE);
 385         }
 386 out:
 387         spin_unlock_irqrestore(&in->lock, flags);
 388         return rc;
 389 }
 390
 391 /*
 392  * debug_info_get
 393  * - increments reference count for debug-info
 394  */
 395 static void debug_info_get(debug_info_t *db_info)
 396 {
 397         if (db_info)
 398                 refcount_inc(&db_info->ref_count);
 399 }
 400
 401 /*
 402  * debug_info_put:
 403  * - decreases reference count for debug-info and frees it if necessary
 404  */
 405 static void debug_info_put(debug_info_t *db_info)
 406 {
 407         int i;
 408
 409         if (!db_info)
 410                 return;
 411         if (refcount_dec_and_test(&db_info->ref_count)) {
 412                 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
 413                         if (!db_info->views[i])
 414                                 continue;
 415                         debugfs_remove(db_info->debugfs_entries[i]);
 416                 }
 417                 debugfs_remove(db_info->debugfs_root_entry);
 418                 if (db_info == debug_area_first)
 419                         debug_area_first = db_info->next;
 420                 if (db_info == debug_area_last)
 421                         debug_area_last = db_info->prev;
 422                 if (db_info->prev)
 423                         db_info->prev->next = db_info->next;
 424                 if (db_info->next)
 425                         db_info->next->prev = db_info->prev;
 426                 debug_info_free(db_info);
 427         }
 428 }
 429
 430 /*
 431  * debug_format_entry:
 432  * - format one debug entry and return size of formated data
 433  */
 434 static int debug_format_entry(file_private_info_t *p_info)
 435 {
 436         debug_info_t *id_snap   = p_info->debug_info_snap;
 437         struct debug_view *view = p_info->view;
 438         debug_entry_t *act_entry;
 439         size_t len = 0;
 440
 441         if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
 442                 /* print prolog */
 443                 if (view->prolog_proc)
 444                         len += view->prolog_proc(id_snap, view, p_info->temp_buf);
 445                 goto out;
 446         }
 447         if (!id_snap->areas) /* this is true, if we have a prolog only view */
 448                 goto out;    /* or if 'pages_per_area' is 0 */
 449         act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
 450                                        [p_info->act_page] + p_info->act_entry);
 451
 452         if (act_entry->id.stck == 0LL)
 453                 goto out; /* empty entry */
 454         if (view->header_proc)
 455                 len += view->header_proc(id_snap, view, p_info->act_area,
 456                                          act_entry, p_info->temp_buf + len);
 457         if (view->format_proc)
 458                 len += view->format_proc(id_snap, view, p_info->temp_buf + len,
 459                                          DEBUG_DATA(act_entry));
 460 out:
 461         return len;
 462 }
 463
 464 /*
 465  * debug_next_entry:
 466  * - goto next entry in p_info
 467  */
 468 static inline int debug_next_entry(file_private_info_t *p_info)
 469 {
 470         debug_info_t *id;
 471
 472         id = p_info->debug_info_snap;
 473         if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
 474                 p_info->act_entry = 0;
 475                 p_info->act_page  = 0;
 476                 goto out;
 477         }
 478         if (!id->areas)
 479                 return 1;
 480         p_info->act_entry += id->entry_size;
 481         /* switch to next page, if we reached the end of the page  */
 482         if (p_info->act_entry > (PAGE_SIZE - id->entry_size)) {
 483                 /* next page */
 484                 p_info->act_entry = 0;
 485                 p_info->act_page += 1;
 486                 if ((p_info->act_page % id->pages_per_area) == 0) {
 487                         /* next area */
 488                         p_info->act_area++;
 489                         p_info->act_page = 0;
 490                 }
 491                 if (p_info->act_area >= id->nr_areas)
 492                         return 1;
 493         }
 494 out:
 495         return 0;
 496 }
 497
 498 /*
 499  * debug_output:
 500  * - called for user read()
 501  * - copies formated debug entries to the user buffer
 502  */
 503 static ssize_t debug_output(struct file *file,          /* file descriptor */
 504                             char __user *user_buf,      /* user buffer */
 505                             size_t len,                 /* length of buffer */
 506                             loff_t *offset)             /* offset in the file */
 507 {
 508         size_t count = 0;
 509         size_t entry_offset;
 510         file_private_info_t *p_info;
 511
 512         p_info = (file_private_info_t *) file->private_data;
 513         if (*offset != p_info->offset)
 514                 return -EPIPE;
 515         if (p_info->act_area >= p_info->debug_info_snap->nr_areas)
 516                 return 0;
 517         entry_offset = p_info->act_entry_offset;
 518         while (count < len) {
 519                 int formatted_line_residue;
 520                 int formatted_line_size;
 521                 int user_buf_residue;
 522                 size_t copy_size;
 523
 524                 formatted_line_size = debug_format_entry(p_info);
 525                 formatted_line_residue = formatted_line_size - entry_offset;
 526                 user_buf_residue = len-count;
 527                 copy_size = min(user_buf_residue, formatted_line_residue);
 528                 if (copy_size) {
 529                         if (copy_to_user(user_buf + count, p_info->temp_buf
 530                                          + entry_offset, copy_size))
 531                                 return -EFAULT;
 532                         count += copy_size;
 533                         entry_offset += copy_size;
 534                 }
 535                 if (copy_size == formatted_line_residue) {
 536                         entry_offset = 0;
 537                         if (debug_next_entry(p_info))
 538                                 goto out;
 539                 }
 540         }
 541 out:
 542         p_info->offset           = *offset + count;
 543         p_info->act_entry_offset = entry_offset;
 544         *offset = p_info->offset;
 545         return count;
 546 }
 547
 548 /*
 549  * debug_input:
 550  * - called for user write()
 551  * - calls input function of view
 552  */
 553 static ssize_t debug_input(struct file *file, const char __user *user_buf,
 554                            size_t length, loff_t *offset)
 555 {
 556         file_private_info_t *p_info;
 557         int rc = 0;
 558
 559         mutex_lock(&debug_mutex);
 560         p_info = ((file_private_info_t *) file->private_data);
 561         if (p_info->view->input_proc) {
 562                 rc = p_info->view->input_proc(p_info->debug_info_org,
 563                                               p_info->view, file, user_buf,
 564                                               length, offset);
 565         } else {
 566                 rc = -EPERM;
 567         }
 568         mutex_unlock(&debug_mutex);
 569         return rc; /* number of input characters */
 570 }
 571
 572 /*
 573  * debug_open:
 574  * - called for user open()
 575  * - copies formated output to private_data area of the file
 576  *   handle
 577  */
 578 static int debug_open(struct inode *inode, struct file *file)
 579 {
 580         debug_info_t *debug_info, *debug_info_snapshot;
 581         file_private_info_t *p_info;
 582         int i, rc = 0;
 583
 584         mutex_lock(&debug_mutex);
 585         debug_info = file_inode(file)->i_private;
 586         /* find debug view */
 587         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
 588                 if (!debug_info->views[i])
 589                         continue;
 590                 else if (debug_info->debugfs_entries[i] == file->f_path.dentry)
 591                         goto found; /* found view ! */
 592         }
 593         /* no entry found */
 594         rc = -EINVAL;
 595         goto out;
 596
 597 found:
 598
 599         /* Make snapshot of current debug areas to get it consistent.     */
 600         /* To copy all the areas is only needed, if we have a view which  */
 601         /* formats the debug areas. */
 602
 603         if (!debug_info->views[i]->format_proc && !debug_info->views[i]->header_proc)
 604                 debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
 605         else
 606                 debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
 607
 608         if (!debug_info_snapshot) {
 609                 rc = -ENOMEM;
 610                 goto out;
 611         }
 612         p_info = kmalloc(sizeof(file_private_info_t), GFP_KERNEL);
 613         if (!p_info) {
 614                 debug_info_free(debug_info_snapshot);
 615                 rc = -ENOMEM;
 616                 goto out;
 617         }
 618         p_info->offset = 0;
 619         p_info->debug_info_snap = debug_info_snapshot;
 620         p_info->debug_info_org  = debug_info;
 621         p_info->view = debug_info->views[i];
 622         p_info->act_area = 0;
 623         p_info->act_page = 0;
 624         p_info->act_entry = DEBUG_PROLOG_ENTRY;
 625         p_info->act_entry_offset = 0;
 626         file->private_data = p_info;
 627         debug_info_get(debug_info);
 628         nonseekable_open(inode, file);
 629 out:
 630         mutex_unlock(&debug_mutex);
 631         return rc;
 632 }
 633
 634 /*
 635  * debug_close:
 636  * - called for user close()
 637  * - deletes  private_data area of the file handle
 638  */
 639 static int debug_close(struct inode *inode, struct file *file)
 640 {
 641         file_private_info_t *p_info;
 642
 643         p_info = (file_private_info_t *) file->private_data;
 644         if (p_info->debug_info_snap)
 645                 debug_info_free(p_info->debug_info_snap);
 646         debug_info_put(p_info->debug_info_org);
 647         kfree(file->private_data);
 648         return 0; /* success */
 649 }
 650
 651 /**
 652  * debug_register_mode() - creates and initializes debug area.
 653  *
 654  * @name:       Name of debug log (e.g. used for debugfs entry)
 655  * @pages_per_area:     Number of pages, which will be allocated per area
 656  * @nr_areas:   Number of debug areas
 657  * @buf_size:   Size of data area in each debug entry
 658  * @mode:       File mode for debugfs files. E.g. S_IRWXUGO
 659  * @uid:        User ID for debugfs files. Currently only 0 is supported.
 660  * @gid:        Group ID for debugfs files. Currently only 0 is supported.
 661  *
 662  * Return:
 663  * - Handle for generated debug area
 664  * - %NULL if register failed
 665  *
 666  * Allocates memory for a debug log.
 667  * Must not be called within an interrupt handler.
 668  */
 669 debug_info_t *debug_register_mode(const char *name, int pages_per_area,
 670                                   int nr_areas, int buf_size, umode_t mode,
 671                                   uid_t uid, gid_t gid)
 672 {
 673         debug_info_t *rc = NULL;
 674
 675         /* Since debugfs currently does not support uid/gid other than root, */
 676         /* we do not allow gid/uid != 0 until we get support for that. */
 677         if ((uid != 0) || (gid != 0))
 678                 pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
 679         BUG_ON(!initialized);
 680         mutex_lock(&debug_mutex);
 681
 682         /* create new debug_info */
 683         rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
 684         if (!rc)
 685                 goto out;
 686         debug_register_view(rc, &debug_level_view);
 687         debug_register_view(rc, &debug_flush_view);
 688         debug_register_view(rc, &debug_pages_view);
 689 out:
 690         if (!rc)
 691                 pr_err("Registering debug feature %s failed\n", name);
 692         mutex_unlock(&debug_mutex);
 693         return rc;
 694 }
 695 EXPORT_SYMBOL(debug_register_mode);
 696
 697 /**
 698  * debug_register() - creates and initializes debug area with default file mode.
 699  *
 700  * @name:       Name of debug log (e.g. used for debugfs entry)
 701  * @pages_per_area:     Number of pages, which will be allocated per area
 702  * @nr_areas:   Number of debug areas
 703  * @buf_size:   Size of data area in each debug entry
 704  *
 705  * Return:
 706  * - Handle for generated debug area
 707  * - %NULL if register failed
 708  *
 709  * Allocates memory for a debug log.
 710  * The debugfs file mode access permissions are read and write for user.
 711  * Must not be called within an interrupt handler.
 712  */
 713 debug_info_t *debug_register(const char *name, int pages_per_area,
 714                              int nr_areas, int buf_size)
 715 {
 716         return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
 717                                    S_IRUSR | S_IWUSR, 0, 0);
 718 }
 719 EXPORT_SYMBOL(debug_register);
 720
 721 /**
 722  * debug_unregister() - give back debug area.
 723  *
 724  * @id:         handle for debug log
 725  *
 726  * Return:
 727  *    none
 728  */
 729 void debug_unregister(debug_info_t *id)
 730 {
 731         if (!id)
 732                 return;
 733         mutex_lock(&debug_mutex);
 734         debug_info_put(id);
 735         mutex_unlock(&debug_mutex);
 736 }
 737 EXPORT_SYMBOL(debug_unregister);
 738
 739 /*
 740  * debug_set_size:
 741  * - set area size (number of pages) and number of areas
 742  */
 743 static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
 744 {
 745         debug_entry_t ***new_areas;
 746         unsigned long flags;
 747         int rc = 0;
 748
 749         if (!id || (nr_areas <= 0) || (pages_per_area < 0))
 750                 return -EINVAL;
 751         if (pages_per_area > 0) {
 752                 new_areas = debug_areas_alloc(pages_per_area, nr_areas);
 753                 if (!new_areas) {
 754                         pr_info("Allocating memory for %i pages failed\n",
 755                                 pages_per_area);
 756                         rc = -ENOMEM;
 757                         goto out;
 758                 }
 759         } else {
 760                 new_areas = NULL;
 761         }
 762         spin_lock_irqsave(&id->lock, flags);
 763         debug_areas_free(id);
 764         id->areas = new_areas;
 765         id->nr_areas = nr_areas;
 766         id->pages_per_area = pages_per_area;
 767         id->active_area = 0;
 768         memset(id->active_entries, 0, sizeof(int)*id->nr_areas);
 769         memset(id->active_pages, 0, sizeof(int)*id->nr_areas);
 770         spin_unlock_irqrestore(&id->lock, flags);
 771         pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
 772 out:
 773         return rc;
 774 }
 775
 776 /**
 777  * debug_set_level() - Sets new actual debug level if new_level is valid.
 778  *
 779  * @id:         handle for debug log
 780  * @new_level:  new debug level
 781  *
 782  * Return:
 783  *    none
 784  */
 785 void debug_set_level(debug_info_t *id, int new_level)
 786 {
 787         unsigned long flags;
 788
 789         if (!id)
 790                 return;
 791         spin_lock_irqsave(&id->lock, flags);
 792         if (new_level == DEBUG_OFF_LEVEL) {
 793                 id->level = DEBUG_OFF_LEVEL;
 794                 pr_info("%s: switched off\n", id->name);
 795         } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
 796                 pr_info("%s: level %i is out of range (%i - %i)\n",
 797                         id->name, new_level, 0, DEBUG_MAX_LEVEL);
 798         } else {
 799                 id->level = new_level;
 800         }
 801         spin_unlock_irqrestore(&id->lock, flags);
 802 }
 803 EXPORT_SYMBOL(debug_set_level);
 804
 805 /*
 806  * proceed_active_entry:
 807  * - set active entry to next in the ring buffer
 808  */
 809 static inline void proceed_active_entry(debug_info_t *id)
 810 {
 811         if ((id->active_entries[id->active_area] += id->entry_size)
 812             > (PAGE_SIZE - id->entry_size)) {
 813                 id->active_entries[id->active_area] = 0;
 814                 id->active_pages[id->active_area] =
 815                         (id->active_pages[id->active_area] + 1) %
 816                         id->pages_per_area;
 817         }
 818 }
 819
 820 /*
 821  * proceed_active_area:
 822  * - set active area to next in the ring buffer
 823  */
 824 static inline void proceed_active_area(debug_info_t *id)
 825 {
 826         id->active_area++;
 827         id->active_area = id->active_area % id->nr_areas;
 828 }
 829
 830 /*
 831  * get_active_entry:
 832  */
 833 static inline debug_entry_t *get_active_entry(debug_info_t *id)
 834 {
 835         return (debug_entry_t *) (((char *) id->areas[id->active_area]
 836                                    [id->active_pages[id->active_area]]) +
 837                                   id->active_entries[id->active_area]);
 838 }
 839
 840 /*
 841  * debug_finish_entry:
 842  * - set timestamp, caller address, cpu number etc.
 843  */
 844
 845 static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
 846                                       int level, int exception)
 847 {
 848         active->id.stck = get_tod_clock_fast() -
 849                 *(unsigned long long *) &tod_clock_base[1];
 850         active->id.fields.cpuid = smp_processor_id();
 851         active->caller = __builtin_return_address(0);
 852         active->id.fields.exception = exception;
 853         active->id.fields.level = level;
 854         proceed_active_entry(id);
 855         if (exception)
 856                 proceed_active_area(id);
 857 }
 858
 859 static int debug_stoppable = 1;
 860 static int debug_active = 1;
 861
 862 #define CTL_S390DBF_STOPPABLE 5678
 863 #define CTL_S390DBF_ACTIVE 5679
 864
 865 /*
 866  * proc handler for the running debug_active sysctl
 867  * always allow read, allow write only if debug_stoppable is set or
 868  * if debug_active is already off
 869  */
 870 static int s390dbf_procactive(struct ctl_table *table, int write,
 871                               void *buffer, size_t *lenp, loff_t *ppos)
 872 {
 873         if (!write || debug_stoppable || !debug_active)
 874                 return proc_dointvec(table, write, buffer, lenp, ppos);
 875         else
 876                 return 0;
 877 }
 878
 879 static struct ctl_table s390dbf_table[] = {
 880         {
 881                 .procname       = "debug_stoppable",
 882                 .data           = &debug_stoppable,
 883                 .maxlen         = sizeof(int),
 884                 .mode           = S_IRUGO | S_IWUSR,
 885                 .proc_handler   = proc_dointvec,
 886         },
 887         {
 888                 .procname       = "debug_active",
 889                 .data           = &debug_active,
 890                 .maxlen         = sizeof(int),
 891                 .mode           = S_IRUGO | S_IWUSR,
 892                 .proc_handler   = s390dbf_procactive,
 893         },
 894         { }
 895 };
 896
 897 static struct ctl_table s390dbf_dir_table[] = {
 898         {
 899                 .procname       = "s390dbf",
 900                 .maxlen         = 0,
 901                 .mode           = S_IRUGO | S_IXUGO,
 902                 .child          = s390dbf_table,
 903         },
 904         { }
 905 };
 906
 907 static struct ctl_table_header *s390dbf_sysctl_header;
 908
 909 /**
 910  * debug_stop_all() - stops the debug feature if stopping is allowed.
 911  *
 912  * Return:
 913  * -   none
 914  *
 915  * Currently used in case of a kernel oops.
 916  */
 917 void debug_stop_all(void)
 918 {
 919         if (debug_stoppable)
 920                 debug_active = 0;
 921 }
 922 EXPORT_SYMBOL(debug_stop_all);
 923
 924 /**
 925  * debug_set_critical() - event/exception functions try lock instead of spin.
 926  *
 927  * Return:
 928  * -   none
 929  *
 930  * Currently used in case of stopping all CPUs but the current one.
 931  * Once in this state, functions to write a debug entry for an
 932  * event or exception no longer spin on the debug area lock,
 933  * but only try to get it and fail if they do not get the lock.
 934  */
 935 void debug_set_critical(void)
 936 {
 937         debug_critical = 1;
 938 }
 939
 940 /*
 941  * debug_event_common:
 942  * - write debug entry with given size
 943  */
 944 debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
 945                                   int len)
 946 {
 947         debug_entry_t *active;
 948         unsigned long flags;
 949
 950         if (!debug_active || !id->areas)
 951                 return NULL;
 952         if (debug_critical) {
 953                 if (!spin_trylock_irqsave(&id->lock, flags))
 954                         return NULL;
 955         } else {
 956                 spin_lock_irqsave(&id->lock, flags);
 957         }
 958         do {
 959                 active = get_active_entry(id);
 960                 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
 961                 if (len < id->buf_size)
 962                         memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
 963                 debug_finish_entry(id, active, level, 0);
 964                 len -= id->buf_size;
 965                 buf += id->buf_size;
 966         } while (len > 0);
 967
 968         spin_unlock_irqrestore(&id->lock, flags);
 969         return active;
 970 }
 971 EXPORT_SYMBOL(debug_event_common);
 972
 973 /*
 974  * debug_exception_common:
 975  * - write debug entry with given size and switch to next debug area
 976  */
 977 debug_entry_t *debug_exception_common(debug_info_t *id, int level,
 978                                       const void *buf, int len)
 979 {
 980         debug_entry_t *active;
 981         unsigned long flags;
 982
 983         if (!debug_active || !id->areas)
 984                 return NULL;
 985         if (debug_critical) {
 986                 if (!spin_trylock_irqsave(&id->lock, flags))
 987                         return NULL;
 988         } else {
 989                 spin_lock_irqsave(&id->lock, flags);
 990         }
 991         do {
 992                 active = get_active_entry(id);
 993                 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
 994                 if (len < id->buf_size)
 995                         memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
 996                 debug_finish_entry(id, active, level, len <= id->buf_size);
 997                 len -= id->buf_size;
 998                 buf += id->buf_size;
 999         } while (len > 0);
1000
1001         spin_unlock_irqrestore(&id->lock, flags);
1002         return active;
1003 }
1004 EXPORT_SYMBOL(debug_exception_common);
1005
1006 /*
1007  * counts arguments in format string for sprintf view
1008  */
1009 static inline int debug_count_numargs(char *string)
1010 {
1011         int numargs = 0;
1012
1013         while (*string) {
1014                 if (*string++ == '%')
1015                         numargs++;
1016         }
1017         return numargs;
1018 }
1019
1020 /*
1021  * debug_sprintf_event:
1022  */
1023 debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
1024 {
1025         debug_sprintf_entry_t *curr_event;
1026         debug_entry_t *active;
1027         unsigned long flags;
1028         int numargs, idx;
1029         va_list ap;
1030
1031         if (!debug_active || !id->areas)
1032                 return NULL;
1033         numargs = debug_count_numargs(string);
1034
1035         if (debug_critical) {
1036                 if (!spin_trylock_irqsave(&id->lock, flags))
1037                         return NULL;
1038         } else {
1039                 spin_lock_irqsave(&id->lock, flags);
1040         }
1041         active = get_active_entry(id);
1042         curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
1043         va_start(ap, string);
1044         curr_event->string = string;
1045         for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1046                 curr_event->args[idx] = va_arg(ap, long);
1047         va_end(ap);
1048         debug_finish_entry(id, active, level, 0);
1049         spin_unlock_irqrestore(&id->lock, flags);
1050
1051         return active;
1052 }
1053 EXPORT_SYMBOL(__debug_sprintf_event);
1054
1055 /*
1056  * debug_sprintf_exception:
1057  */
1058 debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1059 {
1060         debug_sprintf_entry_t *curr_event;
1061         debug_entry_t *active;
1062         unsigned long flags;
1063         int numargs, idx;
1064         va_list ap;
1065
1066         if (!debug_active || !id->areas)
1067                 return NULL;
1068
1069         numargs = debug_count_numargs(string);
1070
1071         if (debug_critical) {
1072                 if (!spin_trylock_irqsave(&id->lock, flags))
1073                         return NULL;
1074         } else {
1075                 spin_lock_irqsave(&id->lock, flags);
1076         }
1077         active = get_active_entry(id);
1078         curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
1079         va_start(ap, string);
1080         curr_event->string = string;
1081         for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1082                 curr_event->args[idx] = va_arg(ap, long);
1083         va_end(ap);
1084         debug_finish_entry(id, active, level, 1);
1085         spin_unlock_irqrestore(&id->lock, flags);
1086
1087         return active;
1088 }
1089 EXPORT_SYMBOL(__debug_sprintf_exception);
1090
1091 /**
1092  * debug_register_view() - registers new debug view and creates debugfs
1093  *                         dir entry
1094  *
1095  * @id:         handle for debug log
1096  * @view:       pointer to debug view struct
1097  *
1098  * Return:
1099  * -   0  : ok
1100  * -   < 0: Error
1101  */
1102 int debug_register_view(debug_info_t *id, struct debug_view *view)
1103 {
1104         unsigned long flags;
1105         struct dentry *pde;
1106         umode_t mode;
1107         int rc = 0;
1108         int i;
1109
1110         if (!id)
1111                 goto out;
1112         mode = (id->mode | S_IFREG) & ~S_IXUGO;
1113         if (!(view->prolog_proc || view->format_proc || view->header_proc))
1114                 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1115         if (!view->input_proc)
1116                 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1117         pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1118                                   id, &debug_file_ops);
1119         spin_lock_irqsave(&id->lock, flags);
1120         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1121                 if (!id->views[i])
1122                         break;
1123         }
1124         if (i == DEBUG_MAX_VIEWS) {
1125                 pr_err("Registering view %s/%s would exceed the maximum "
1126                        "number of views %i\n", id->name, view->name, i);
1127                 rc = -1;
1128         } else {
1129                 id->views[i] = view;
1130                 id->debugfs_entries[i] = pde;
1131         }
1132         spin_unlock_irqrestore(&id->lock, flags);
1133         if (rc)
1134                 debugfs_remove(pde);
1135 out:
1136         return rc;
1137 }
1138 EXPORT_SYMBOL(debug_register_view);
1139
1140 /**
1141  * debug_unregister_view() - unregisters debug view and removes debugfs
1142  *                           dir entry
1143  *
1144  * @id:         handle for debug log
1145  * @view:       pointer to debug view struct
1146  *
1147  * Return:
1148  * -   0  : ok
1149  * -   < 0: Error
1150  */
1151 int debug_unregister_view(debug_info_t *id, struct debug_view *view)
1152 {
1153         struct dentry *dentry = NULL;
1154         unsigned long flags;
1155         int i, rc = 0;
1156
1157         if (!id)
1158                 goto out;
1159         spin_lock_irqsave(&id->lock, flags);
1160         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1161                 if (id->views[i] == view)
1162                         break;
1163         }
1164         if (i == DEBUG_MAX_VIEWS) {
1165                 rc = -1;
1166         } else {
1167                 dentry = id->debugfs_entries[i];
1168                 id->views[i] = NULL;
1169                 id->debugfs_entries[i] = NULL;
1170         }
1171         spin_unlock_irqrestore(&id->lock, flags);
1172         debugfs_remove(dentry);
1173 out:
1174         return rc;
1175 }
1176 EXPORT_SYMBOL(debug_unregister_view);
1177
1178 static inline char *debug_get_user_string(const char __user *user_buf,
1179                                           size_t user_len)
1180 {
1181         char *buffer;
1182
1183         buffer = kmalloc(user_len + 1, GFP_KERNEL);
1184         if (!buffer)
1185                 return ERR_PTR(-ENOMEM);
1186         if (copy_from_user(buffer, user_buf, user_len) != 0) {
1187                 kfree(buffer);
1188                 return ERR_PTR(-EFAULT);
1189         }
1190         /* got the string, now strip linefeed. */
1191         if (buffer[user_len - 1] == '\n')
1192                 buffer[user_len - 1] = 0;
1193         else
1194                 buffer[user_len] = 0;
1195         return buffer;
1196 }
1197
1198 static inline int debug_get_uint(char *buf)
1199 {
1200         int rc;
1201
1202         buf = skip_spaces(buf);
1203         rc = simple_strtoul(buf, &buf, 10);
1204         if (*buf)
1205                 rc = -EINVAL;
1206         return rc;
1207 }
1208
1209 /*
1210  * functions for debug-views
1211  ***********************************
1212 */
1213
1214 /*
1215  * prints out actual debug level
1216  */
1217
1218 static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
1219                                  char *out_buf)
1220 {
1221         return sprintf(out_buf, "%i\n", id->pages_per_area);
1222 }
1223
1224 /*
1225  * reads new size (number of pages per debug area)
1226  */
1227
1228 static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
1229                                 struct file *file, const char __user *user_buf,
1230                                 size_t user_len, loff_t *offset)
1231 {
1232         int rc, new_pages;
1233         char *str;
1234
1235         if (user_len > 0x10000)
1236                 user_len = 0x10000;
1237         if (*offset != 0) {
1238                 rc = -EPIPE;
1239                 goto out;
1240         }
1241         str = debug_get_user_string(user_buf, user_len);
1242         if (IS_ERR(str)) {
1243                 rc = PTR_ERR(str);
1244                 goto out;
1245         }
1246         new_pages = debug_get_uint(str);
1247         if (new_pages < 0) {
1248                 rc = -EINVAL;
1249                 goto free_str;
1250         }
1251         rc = debug_set_size(id, id->nr_areas, new_pages);
1252         if (rc != 0) {
1253                 rc = -EINVAL;
1254                 goto free_str;
1255         }
1256         rc = user_len;
1257 free_str:
1258         kfree(str);
1259 out:
1260         *offset += user_len;
1261         return rc;              /* number of input characters */
1262 }
1263
1264 /*
1265  * prints out actual debug level
1266  */
1267 static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
1268                                  char *out_buf)
1269 {
1270         int rc = 0;
1271
1272         if (id->level == DEBUG_OFF_LEVEL)
1273                 rc = sprintf(out_buf, "-\n");
1274         else
1275                 rc = sprintf(out_buf, "%i\n", id->level);
1276         return rc;
1277 }
1278
1279 /*
1280  * reads new debug level
1281  */
1282 static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
1283                                 struct file *file, const char __user *user_buf,
1284                                 size_t user_len, loff_t *offset)
1285 {
1286         int rc, new_level;
1287         char *str;
1288
1289         if (user_len > 0x10000)
1290                 user_len = 0x10000;
1291         if (*offset != 0) {
1292                 rc = -EPIPE;
1293                 goto out;
1294         }
1295         str = debug_get_user_string(user_buf, user_len);
1296         if (IS_ERR(str)) {
1297                 rc = PTR_ERR(str);
1298                 goto out;
1299         }
1300         if (str[0] == '-') {
1301                 debug_set_level(id, DEBUG_OFF_LEVEL);
1302                 rc = user_len;
1303                 goto free_str;
1304         } else {
1305                 new_level = debug_get_uint(str);
1306         }
1307         if (new_level < 0) {
1308                 pr_warn("%s is not a valid level for a debug feature\n", str);
1309                 rc = -EINVAL;
1310         } else {
1311                 debug_set_level(id, new_level);
1312                 rc = user_len;
1313         }
1314 free_str:
1315         kfree(str);
1316 out:
1317         *offset += user_len;
1318         return rc;              /* number of input characters */
1319 }
1320
1321 /*
1322  * flushes debug areas
1323  */
1324 static void debug_flush(debug_info_t *id, int area)
1325 {
1326         unsigned long flags;
1327         int i, j;
1328
1329         if (!id || !id->areas)
1330                 return;
1331         spin_lock_irqsave(&id->lock, flags);
1332         if (area == DEBUG_FLUSH_ALL) {
1333                 id->active_area = 0;
1334                 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1335                 for (i = 0; i < id->nr_areas; i++) {
1336                         id->active_pages[i] = 0;
1337                         for (j = 0; j < id->pages_per_area; j++)
1338                                 memset(id->areas[i][j], 0, PAGE_SIZE);
1339                 }
1340         } else if (area >= 0 && area < id->nr_areas) {
1341                 id->active_entries[area] = 0;
1342                 id->active_pages[area] = 0;
1343                 for (i = 0; i < id->pages_per_area; i++)
1344                         memset(id->areas[area][i], 0, PAGE_SIZE);
1345         }
1346         spin_unlock_irqrestore(&id->lock, flags);
1347 }
1348
1349 /*
1350  * view function: flushes debug areas
1351  */
1352 static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
1353                                 struct file *file, const char __user *user_buf,
1354                                 size_t user_len, loff_t *offset)
1355 {
1356         char input_buf[1];
1357         int rc = user_len;
1358
1359         if (user_len > 0x10000)
1360                 user_len = 0x10000;
1361         if (*offset != 0) {
1362                 rc = -EPIPE;
1363                 goto out;
1364         }
1365         if (copy_from_user(input_buf, user_buf, 1)) {
1366                 rc = -EFAULT;
1367                 goto out;
1368         }
1369         if (input_buf[0] == '-') {
1370                 debug_flush(id, DEBUG_FLUSH_ALL);
1371                 goto out;
1372         }
1373         if (isdigit(input_buf[0])) {
1374                 int area = ((int) input_buf[0] - (int) '0');
1375
1376                 debug_flush(id, area);
1377                 goto out;
1378         }
1379
1380         pr_info("Flushing debug data failed because %c is not a valid "
1381                  "area\n", input_buf[0]);
1382
1383 out:
1384         *offset += user_len;
1385         return rc;              /* number of input characters */
1386 }
1387
1388 /*
1389  * prints debug header in raw format
1390  */
1391 static int debug_raw_header_fn(debug_info_t *id, struct debug_view *view,
1392                                int area, debug_entry_t *entry, char *out_buf)
1393 {
1394         int rc;
1395
1396         rc = sizeof(debug_entry_t);
1397         memcpy(out_buf, entry, sizeof(debug_entry_t));
1398         return rc;
1399 }
1400
1401 /*
1402  * prints debug data in raw format
1403  */
1404 static int debug_raw_format_fn(debug_info_t *id, struct debug_view *view,
1405                                char *out_buf, const char *in_buf)
1406 {
1407         int rc;
1408
1409         rc = id->buf_size;
1410         memcpy(out_buf, in_buf, id->buf_size);
1411         return rc;
1412 }
1413
1414 /*
1415  * prints debug data in hex/ascii format
1416  */
1417 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
1418                                      char *out_buf, const char *in_buf)
1419 {
1420         int i, rc = 0;
1421
1422         for (i = 0; i < id->buf_size; i++)
1423                 rc += sprintf(out_buf + rc, "%02x ", ((unsigned char *) in_buf)[i]);
1424         rc += sprintf(out_buf + rc, "| ");
1425         for (i = 0; i < id->buf_size; i++) {
1426                 unsigned char c = in_buf[i];
1427
1428                 if (isascii(c) && isprint(c))
1429                         rc += sprintf(out_buf + rc, "%c", c);
1430                 else
1431                         rc += sprintf(out_buf + rc, ".");
1432         }
1433         rc += sprintf(out_buf + rc, "\n");
1434         return rc;
1435 }
1436
1437 /*
1438  * prints header for debug entry
1439  */
1440 int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
1441                          int area, debug_entry_t *entry, char *out_buf)
1442 {
1443         unsigned long base, sec, usec;
1444         unsigned long caller;
1445         unsigned int level;
1446         char *except_str;
1447         int rc = 0;
1448
1449         level = entry->id.fields.level;
1450         base = (*(unsigned long *) &tod_clock_base[0]) >> 4;
1451         sec = (entry->id.stck >> 12) + base - (TOD_UNIX_EPOCH >> 12);
1452         usec = do_div(sec, USEC_PER_SEC);
1453
1454         if (entry->id.fields.exception)
1455                 except_str = "*";
1456         else
1457                 except_str = "-";
1458         caller = (unsigned long) entry->caller;
1459         rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %02i %pK  ",
1460                       area, sec, usec, level, except_str,
1461                       entry->id.fields.cpuid, (void *)caller);
1462         return rc;
1463 }
1464 EXPORT_SYMBOL(debug_dflt_header_fn);
1465
1466 /*
1467  * prints debug data sprintf-formated:
1468  * debug_sprinf_event/exception calls must be used together with this view
1469  */
1470
1471 #define DEBUG_SPRINTF_MAX_ARGS 10
1472
1473 static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
1474                                    char *out_buf, debug_sprintf_entry_t *curr_event)
1475 {
1476         int num_longs, num_used_args = 0, i, rc = 0;
1477         int index[DEBUG_SPRINTF_MAX_ARGS];
1478
1479         /* count of longs fit into one entry */
1480         num_longs = id->buf_size / sizeof(long);
1481
1482         if (num_longs < 1)
1483                 goto out; /* bufsize of entry too small */
1484         if (num_longs == 1) {
1485                 /* no args, we use only the string */
1486                 strcpy(out_buf, curr_event->string);
1487                 rc = strlen(curr_event->string);
1488                 goto out;
1489         }
1490
1491         /* number of arguments used for sprintf (without the format string) */
1492         num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1493
1494         memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1495
1496         for (i = 0; i < num_used_args; i++)
1497                 index[i] = i;
1498
1499         rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1500                      curr_event->args[index[1]], curr_event->args[index[2]],
1501                      curr_event->args[index[3]], curr_event->args[index[4]],
1502                      curr_event->args[index[5]], curr_event->args[index[6]],
1503                      curr_event->args[index[7]], curr_event->args[index[8]],
1504                      curr_event->args[index[9]]);
1505 out:
1506         return rc;
1507 }
1508
1509 /*
1510  * debug_init:
1511  * - is called exactly once to initialize the debug feature
1512  */
1513 static int __init debug_init(void)
1514 {
1515         s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
1516         mutex_lock(&debug_mutex);
1517         debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1518         initialized = 1;
1519         mutex_unlock(&debug_mutex);
1520         return 0;
1521 }
1522 postcore_initcall(debug_init);