arch/s390/kernel/debug.c

   1 /*
   2  *   S/390 debug facility
   3  *
   4  *    Copyright IBM Corp. 1999, 2012
   5  *
   6  *    Author(s): Michael Holzheu (holzheu@de.ibm.com),
   7  *               Holger Smolinski (Holger.Smolinski@de.ibm.com)
   8  *
   9  *    Bugreports to: <Linux390@de.ibm.com>
  10  */
  11
  12 #define KMSG_COMPONENT "s390dbf"
  13 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  14
  15 #include <linux/stddef.h>
  16 #include <linux/kernel.h>
  17 #include <linux/errno.h>
  18 #include <linux/slab.h>
  19 #include <linux/ctype.h>
  20 #include <linux/string.h>
  21 #include <linux/sysctl.h>
  22 #include <linux/uaccess.h>
  23 #include <linux/export.h>
  24 #include <linux/init.h>
  25 #include <linux/fs.h>
  26 #include <linux/debugfs.h>
  27
  28 #include <asm/debug.h>
  29
  30 #define DEBUG_PROLOG_ENTRY -1
  31
  32 #define ALL_AREAS 0 /* copy all debug areas */
  33 #define NO_AREAS  1 /* copy no debug areas */
  34
  35 /* typedefs */
  36
  37 typedef struct file_private_info {
  38         loff_t offset;                  /* offset of last read in file */
  39         int    act_area;                /* number of last formated area */
  40         int    act_page;                /* act page in given area */
  41         int    act_entry;               /* last formated entry (offset */
  42                                         /* relative to beginning of last */
  43                                         /* formated page) */
  44         size_t act_entry_offset;        /* up to this offset we copied */
  45                                         /* in last read the last formated */
  46                                         /* entry to userland */
  47         char   temp_buf[2048];          /* buffer for output */
  48         debug_info_t *debug_info_org;   /* original debug information */
  49         debug_info_t *debug_info_snap;  /* snapshot of debug information */
  50         struct debug_view *view;        /* used view of debug info */
  51 } file_private_info_t;
  52
  53 typedef struct
  54 {
  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
  66 /* internal function prototyes */
  67
  68 static int debug_init(void);
  69 static ssize_t debug_output(struct file *file, char __user *user_buf,
  70                         size_t user_len, loff_t * offset);
  71 static ssize_t debug_input(struct file *file, const char __user *user_buf,
  72                         size_t user_len, loff_t * offset);
  73 static int debug_open(struct inode *inode, struct file *file);
  74 static int debug_close(struct inode *inode, struct file *file);
  75 static debug_info_t *debug_info_create(const char *name, int pages_per_area,
  76                         int nr_areas, int buf_size, umode_t mode);
  77 static void debug_info_get(debug_info_t *);
  78 static void debug_info_put(debug_info_t *);
  79 static int debug_prolog_level_fn(debug_info_t * id,
  80                         struct debug_view *view, char *out_buf);
  81 static int debug_input_level_fn(debug_info_t * id, struct debug_view *view,
  82                         struct file *file, const char __user *user_buf,
  83                         size_t user_buf_size, loff_t * offset);
  84 static int debug_prolog_pages_fn(debug_info_t * id,
  85                         struct debug_view *view, char *out_buf);
  86 static int debug_input_pages_fn(debug_info_t * id, struct debug_view *view,
  87                         struct file *file, const char __user *user_buf,
  88                         size_t user_buf_size, loff_t * offset);
  89 static int debug_input_flush_fn(debug_info_t * id, struct debug_view *view,
  90                         struct file *file, const char __user *user_buf,
  91                         size_t user_buf_size, loff_t * offset);
  92 static int debug_hex_ascii_format_fn(debug_info_t * id, struct debug_view *view,
  93                         char *out_buf, const char *in_buf);
  94 static int debug_raw_format_fn(debug_info_t * id,
  95                         struct debug_view *view, char *out_buf,
  96                         const char *in_buf);
  97 static int debug_raw_header_fn(debug_info_t * id, struct debug_view *view,
  98                         int area, debug_entry_t * entry, char *out_buf);
  99
 100 static int debug_sprintf_format_fn(debug_info_t * id, struct debug_view *view,
 101                         char *out_buf, debug_sprintf_entry_t *curr_event);
 102
 103 /* globals */
 104
 105 struct debug_view debug_raw_view = {
 106         "raw",
 107         NULL,
 108         &debug_raw_header_fn,
 109         &debug_raw_format_fn,
 110         NULL,
 111         NULL
 112 };
 113 EXPORT_SYMBOL(debug_raw_view);
 114
 115 struct debug_view debug_hex_ascii_view = {
 116         "hex_ascii",
 117         NULL,
 118         &debug_dflt_header_fn,
 119         &debug_hex_ascii_format_fn,
 120         NULL,
 121         NULL
 122 };
 123 EXPORT_SYMBOL(debug_hex_ascii_view);
 124
 125 static struct debug_view debug_level_view = {
 126         "level",
 127         &debug_prolog_level_fn,
 128         NULL,
 129         NULL,
 130         &debug_input_level_fn,
 131         NULL
 132 };
 133
 134 static struct debug_view debug_pages_view = {
 135         "pages",
 136         &debug_prolog_pages_fn,
 137         NULL,
 138         NULL,
 139         &debug_input_pages_fn,
 140         NULL
 141 };
 142
 143 static struct debug_view debug_flush_view = {
 144         "flush",
 145         NULL,
 146         NULL,
 147         NULL,
 148         &debug_input_flush_fn,
 149         NULL
 150 };
 151
 152 struct debug_view debug_sprintf_view = {
 153         "sprintf",
 154         NULL,
 155         &debug_dflt_header_fn,
 156         (debug_format_proc_t*)&debug_sprintf_format_fn,
 157         NULL,
 158         NULL
 159 };
 160 EXPORT_SYMBOL(debug_sprintf_view);
 161
 162 /* used by dump analysis tools to determine version of debug feature */
 163 static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
 164
 165 /* static globals */
 166
 167 static debug_info_t *debug_area_first = NULL;
 168 static debug_info_t *debug_area_last = NULL;
 169 static DEFINE_MUTEX(debug_mutex);
 170
 171 static int initialized;
 172 static int debug_critical;
 173
 174 static const struct file_operations debug_file_ops = {
 175         .owner   = THIS_MODULE,
 176         .read    = debug_output,
 177         .write   = debug_input,
 178         .open    = debug_open,
 179         .release = debug_close,
 180         .llseek  = no_llseek,
 181 };
 182
 183 static struct dentry *debug_debugfs_root_entry;
 184
 185 /* functions */
 186
 187 /*
 188  * debug_areas_alloc
 189  * - Debug areas are implemented as a threedimensonal array:
 190  *   areas[areanumber][pagenumber][pageoffset]
 191  */
 192
 193 static debug_entry_t***
 194 debug_areas_alloc(int pages_per_area, int nr_areas)
 195 {
 196         debug_entry_t*** areas;
 197         int i,j;
 198
 199         areas = kmalloc(nr_areas *
 200                                         sizeof(debug_entry_t**),
 201                                         GFP_KERNEL);
 202         if (!areas)
 203                 goto fail_malloc_areas;
 204         for (i = 0; i < nr_areas; i++) {
 205                 areas[i] = kmalloc(pages_per_area *
 206                                 sizeof(debug_entry_t*),GFP_KERNEL);
 207                 if (!areas[i]) {
 208                         goto fail_malloc_areas2;
 209                 }
 210                 for(j = 0; j < pages_per_area; j++) {
 211                         areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
 212                         if(!areas[i][j]) {
 213                                 for(j--; j >=0 ; j--) {
 214                                         kfree(areas[i][j]);
 215                                 }
 216                                 kfree(areas[i]);
 217                                 goto fail_malloc_areas2;
 218                         }
 219                 }
 220         }
 221         return areas;
 222
 223 fail_malloc_areas2:
 224         for(i--; i >= 0; i--){
 225                 for(j=0; j < pages_per_area;j++){
 226                         kfree(areas[i][j]);
 227                 }
 228                 kfree(areas[i]);
 229         }
 230         kfree(areas);
 231 fail_malloc_areas:
 232         return NULL;
 233
 234 }
 235
 236
 237 /*
 238  * debug_info_alloc
 239  * - alloc new debug-info
 240  */
 241
 242 static debug_info_t*
 243 debug_info_alloc(const char *name, int pages_per_area, int nr_areas,
 244                  int buf_size, int level, int mode)
 245 {
 246         debug_info_t* rc;
 247
 248         /* alloc everything */
 249
 250         rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
 251         if(!rc)
 252                 goto fail_malloc_rc;
 253         rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
 254         if(!rc->active_entries)
 255                 goto fail_malloc_active_entries;
 256         rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
 257         if(!rc->active_pages)
 258                 goto fail_malloc_active_pages;
 259         if((mode == ALL_AREAS) && (pages_per_area != 0)){
 260                 rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
 261                 if(!rc->areas)
 262                         goto fail_malloc_areas;
 263         } else {
 264                 rc->areas = NULL;
 265         }
 266
 267         /* initialize members */
 268
 269         spin_lock_init(&rc->lock);
 270         rc->pages_per_area = pages_per_area;
 271         rc->nr_areas       = nr_areas;
 272         rc->active_area    = 0;
 273         rc->level          = level;
 274         rc->buf_size       = buf_size;
 275         rc->entry_size     = sizeof(debug_entry_t) + buf_size;
 276         strlcpy(rc->name, name, sizeof(rc->name));
 277         memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
 278         memset(rc->debugfs_entries, 0 ,DEBUG_MAX_VIEWS *
 279                 sizeof(struct dentry*));
 280         atomic_set(&(rc->ref_count), 0);
 281
 282         return rc;
 283
 284 fail_malloc_areas:
 285         kfree(rc->active_pages);
 286 fail_malloc_active_pages:
 287         kfree(rc->active_entries);
 288 fail_malloc_active_entries:
 289         kfree(rc);
 290 fail_malloc_rc:
 291         return NULL;
 292 }
 293
 294 /*
 295  * debug_areas_free
 296  * - free all debug areas
 297  */
 298
 299 static void
 300 debug_areas_free(debug_info_t* db_info)
 301 {
 302         int i,j;
 303
 304         if(!db_info->areas)
 305                 return;
 306         for (i = 0; i < db_info->nr_areas; i++) {
 307                 for(j = 0; j < db_info->pages_per_area; j++) {
 308                         kfree(db_info->areas[i][j]);
 309                 }
 310                 kfree(db_info->areas[i]);
 311         }
 312         kfree(db_info->areas);
 313         db_info->areas = NULL;
 314 }
 315
 316 /*
 317  * debug_info_free
 318  * - free memory debug-info
 319  */
 320
 321 static void
 322 debug_info_free(debug_info_t* db_info){
 323         debug_areas_free(db_info);
 324         kfree(db_info->active_entries);
 325         kfree(db_info->active_pages);
 326         kfree(db_info);
 327 }
 328
 329 /*
 330  * debug_info_create
 331  * - create new debug-info
 332  */
 333
 334 static debug_info_t*
 335 debug_info_create(const char *name, int pages_per_area, int nr_areas,
 336                   int buf_size, umode_t mode)
 337 {
 338         debug_info_t* rc;
 339
 340         rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
 341                                 DEBUG_DEFAULT_LEVEL, ALL_AREAS);
 342         if(!rc)
 343                 goto out;
 344
 345         rc->mode = mode & ~S_IFMT;
 346
 347         /* create root directory */
 348         rc->debugfs_root_entry = debugfs_create_dir(rc->name,
 349                                         debug_debugfs_root_entry);
 350
 351         /* append new element to linked list */
 352         if (!debug_area_first) {
 353                 /* first element in list */
 354                 debug_area_first = rc;
 355                 rc->prev = NULL;
 356         } else {
 357                 /* append element to end of list */
 358                 debug_area_last->next = rc;
 359                 rc->prev = debug_area_last;
 360         }
 361         debug_area_last = rc;
 362         rc->next = NULL;
 363
 364         debug_info_get(rc);
 365 out:
 366         return rc;
 367 }
 368
 369 /*
 370  * debug_info_copy
 371  * - copy debug-info
 372  */
 373
 374 static debug_info_t*
 375 debug_info_copy(debug_info_t* in, int mode)
 376 {
 377         int i,j;
 378         debug_info_t* rc;
 379         unsigned long flags;
 380
 381         /* get a consistent copy of the debug areas */
 382         do {
 383                 rc = debug_info_alloc(in->name, in->pages_per_area,
 384                         in->nr_areas, in->buf_size, in->level, mode);
 385                 spin_lock_irqsave(&in->lock, flags);
 386                 if(!rc)
 387                         goto out;
 388                 /* has something changed in the meantime ? */
 389                 if((rc->pages_per_area == in->pages_per_area) &&
 390                    (rc->nr_areas == in->nr_areas)) {
 391                         break;
 392                 }
 393                 spin_unlock_irqrestore(&in->lock, flags);
 394                 debug_info_free(rc);
 395         } while (1);
 396
 397         if (mode == NO_AREAS)
 398                 goto out;
 399
 400         for(i = 0; i < in->nr_areas; i++){
 401                 for(j = 0; j < in->pages_per_area; j++) {
 402                         memcpy(rc->areas[i][j], in->areas[i][j],PAGE_SIZE);
 403                 }
 404         }
 405 out:
 406         spin_unlock_irqrestore(&in->lock, flags);
 407         return rc;
 408 }
 409
 410 /*
 411  * debug_info_get
 412  * - increments reference count for debug-info
 413  */
 414
 415 static void
 416 debug_info_get(debug_info_t * db_info)
 417 {
 418         if (db_info)
 419                 atomic_inc(&db_info->ref_count);
 420 }
 421
 422 /*
 423  * debug_info_put:
 424  * - decreases reference count for debug-info and frees it if necessary
 425  */
 426
 427 static void
 428 debug_info_put(debug_info_t *db_info)
 429 {
 430         int i;
 431
 432         if (!db_info)
 433                 return;
 434         if (atomic_dec_and_test(&db_info->ref_count)) {
 435                 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
 436                         if (!db_info->views[i])
 437                                 continue;
 438                         debugfs_remove(db_info->debugfs_entries[i]);
 439                 }
 440                 debugfs_remove(db_info->debugfs_root_entry);
 441                 if(db_info == debug_area_first)
 442                         debug_area_first = db_info->next;
 443                 if(db_info == debug_area_last)
 444                         debug_area_last = db_info->prev;
 445                 if(db_info->prev) db_info->prev->next = db_info->next;
 446                 if(db_info->next) db_info->next->prev = db_info->prev;
 447                 debug_info_free(db_info);
 448         }
 449 }
 450
 451 /*
 452  * debug_format_entry:
 453  * - format one debug entry and return size of formated data
 454  */
 455
 456 static int
 457 debug_format_entry(file_private_info_t *p_info)
 458 {
 459         debug_info_t *id_snap   = p_info->debug_info_snap;
 460         struct debug_view *view = p_info->view;
 461         debug_entry_t *act_entry;
 462         size_t len = 0;
 463         if(p_info->act_entry == DEBUG_PROLOG_ENTRY){
 464                 /* print prolog */
 465                 if (view->prolog_proc)
 466                         len += view->prolog_proc(id_snap,view,p_info->temp_buf);
 467                 goto out;
 468         }
 469         if (!id_snap->areas) /* this is true, if we have a prolog only view */
 470                 goto out;    /* or if 'pages_per_area' is 0 */
 471         act_entry = (debug_entry_t *) ((char*)id_snap->areas[p_info->act_area]
 472                                 [p_info->act_page] + p_info->act_entry);
 473
 474         if (act_entry->id.stck == 0LL)
 475                         goto out;  /* empty entry */
 476         if (view->header_proc)
 477                 len += view->header_proc(id_snap, view, p_info->act_area,
 478                                         act_entry, p_info->temp_buf + len);
 479         if (view->format_proc)
 480                 len += view->format_proc(id_snap, view, p_info->temp_buf + len,
 481                                                 DEBUG_DATA(act_entry));
 482 out:
 483         return len;
 484 }
 485
 486 /*
 487  * debug_next_entry:
 488  * - goto next entry in p_info
 489  */
 490
 491 static inline int
 492 debug_next_entry(file_private_info_t *p_info)
 493 {
 494         debug_info_t *id;
 495
 496         id = p_info->debug_info_snap;
 497         if(p_info->act_entry == DEBUG_PROLOG_ENTRY){
 498                 p_info->act_entry = 0;
 499                 p_info->act_page  = 0;
 500                 goto out;
 501         }
 502         if(!id->areas)
 503                 return 1;
 504         p_info->act_entry += id->entry_size;
 505         /* switch to next page, if we reached the end of the page  */
 506         if (p_info->act_entry > (PAGE_SIZE - id->entry_size)){
 507                 /* next page */
 508                 p_info->act_entry = 0;
 509                 p_info->act_page += 1;
 510                 if((p_info->act_page % id->pages_per_area) == 0) {
 511                         /* next area */
 512                         p_info->act_area++;
 513                         p_info->act_page=0;
 514                 }
 515                 if(p_info->act_area >= id->nr_areas)
 516                         return 1;
 517         }
 518 out:
 519         return 0;
 520 }
 521
 522 /*
 523  * debug_output:
 524  * - called for user read()
 525  * - copies formated debug entries to the user buffer
 526  */
 527
 528 static ssize_t
 529 debug_output(struct file *file,         /* file descriptor */
 530             char __user *user_buf,      /* user buffer */
 531             size_t  len,                /* length of buffer */
 532             loff_t *offset)             /* offset in the file */
 533 {
 534         size_t count = 0;
 535         size_t entry_offset;
 536         file_private_info_t *p_info;
 537
 538         p_info = ((file_private_info_t *) file->private_data);
 539         if (*offset != p_info->offset)
 540                 return -EPIPE;
 541         if(p_info->act_area >= p_info->debug_info_snap->nr_areas)
 542                 return 0;
 543         entry_offset = p_info->act_entry_offset;
 544         while(count < len){
 545                 int formatted_line_size;
 546                 int formatted_line_residue;
 547                 int user_buf_residue;
 548                 size_t copy_size;
 549
 550                 formatted_line_size = debug_format_entry(p_info);
 551                 formatted_line_residue = formatted_line_size - entry_offset;
 552                 user_buf_residue = len-count;
 553                 copy_size = min(user_buf_residue, formatted_line_residue);
 554                 if(copy_size){
 555                         if (copy_to_user(user_buf + count, p_info->temp_buf
 556                                         + entry_offset, copy_size))
 557                                 return -EFAULT;
 558                         count += copy_size;
 559                         entry_offset += copy_size;
 560                 }
 561                 if(copy_size == formatted_line_residue){
 562                         entry_offset = 0;
 563                         if(debug_next_entry(p_info))
 564                                 goto out;
 565                 }
 566         }
 567 out:
 568         p_info->offset           = *offset + count;
 569         p_info->act_entry_offset = entry_offset;
 570         *offset = p_info->offset;
 571         return count;
 572 }
 573
 574 /*
 575  * debug_input:
 576  * - called for user write()
 577  * - calls input function of view
 578  */
 579
 580 static ssize_t
 581 debug_input(struct file *file, const char __user *user_buf, size_t length,
 582                 loff_t *offset)
 583 {
 584         int rc = 0;
 585         file_private_info_t *p_info;
 586
 587         mutex_lock(&debug_mutex);
 588         p_info = ((file_private_info_t *) file->private_data);
 589         if (p_info->view->input_proc)
 590                 rc = p_info->view->input_proc(p_info->debug_info_org,
 591                                               p_info->view, file, user_buf,
 592                                               length, offset);
 593         else
 594                 rc = -EPERM;
 595         mutex_unlock(&debug_mutex);
 596         return rc;              /* number of input characters */
 597 }
 598
 599 /*
 600  * debug_open:
 601  * - called for user open()
 602  * - copies formated output to private_data area of the file
 603  *   handle
 604  */
 605
 606 static int
 607 debug_open(struct inode *inode, struct file *file)
 608 {
 609         int i, rc = 0;
 610         file_private_info_t *p_info;
 611         debug_info_t *debug_info, *debug_info_snapshot;
 612
 613         mutex_lock(&debug_mutex);
 614         debug_info = file_inode(file)->i_private;
 615         /* find debug view */
 616         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
 617                 if (!debug_info->views[i])
 618                         continue;
 619                 else if (debug_info->debugfs_entries[i] ==
 620                          file->f_path.dentry) {
 621                         goto found;     /* found view ! */
 622                 }
 623         }
 624         /* no entry found */
 625         rc = -EINVAL;
 626         goto out;
 627
 628 found:
 629
 630         /* Make snapshot of current debug areas to get it consistent.     */
 631         /* To copy all the areas is only needed, if we have a view which  */
 632         /* formats the debug areas. */
 633
 634         if(!debug_info->views[i]->format_proc &&
 635                 !debug_info->views[i]->header_proc){
 636                 debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
 637         } else {
 638                 debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
 639         }
 640
 641         if(!debug_info_snapshot){
 642                 rc = -ENOMEM;
 643                 goto out;
 644         }
 645         p_info = kmalloc(sizeof(file_private_info_t),
 646                                                 GFP_KERNEL);
 647         if(!p_info){
 648                 debug_info_free(debug_info_snapshot);
 649                 rc = -ENOMEM;
 650                 goto out;
 651         }
 652         p_info->offset = 0;
 653         p_info->debug_info_snap = debug_info_snapshot;
 654         p_info->debug_info_org  = debug_info;
 655         p_info->view = debug_info->views[i];
 656         p_info->act_area = 0;
 657         p_info->act_page = 0;
 658         p_info->act_entry = DEBUG_PROLOG_ENTRY;
 659         p_info->act_entry_offset = 0;
 660         file->private_data = p_info;
 661         debug_info_get(debug_info);
 662         nonseekable_open(inode, file);
 663 out:
 664         mutex_unlock(&debug_mutex);
 665         return rc;
 666 }
 667
 668 /*
 669  * debug_close:
 670  * - called for user close()
 671  * - deletes  private_data area of the file handle
 672  */
 673
 674 static int
 675 debug_close(struct inode *inode, struct file *file)
 676 {
 677         file_private_info_t *p_info;
 678         p_info = (file_private_info_t *) file->private_data;
 679         if(p_info->debug_info_snap)
 680                 debug_info_free(p_info->debug_info_snap);
 681         debug_info_put(p_info->debug_info_org);
 682         kfree(file->private_data);
 683         return 0;               /* success */
 684 }
 685
 686 /*
 687  * debug_register_mode:
 688  * - Creates and initializes debug area for the caller
 689  *   The mode parameter allows to specify access rights for the s390dbf files
 690  * - Returns handle for debug area
 691  */
 692
 693 debug_info_t *debug_register_mode(const char *name, int pages_per_area,
 694                                   int nr_areas, int buf_size, umode_t mode,
 695                                   uid_t uid, gid_t gid)
 696 {
 697         debug_info_t *rc = NULL;
 698
 699         /* Since debugfs currently does not support uid/gid other than root, */
 700         /* we do not allow gid/uid != 0 until we get support for that. */
 701         if ((uid != 0) || (gid != 0))
 702                 pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
 703         BUG_ON(!initialized);
 704         mutex_lock(&debug_mutex);
 705
 706         /* create new debug_info */
 707
 708         rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
 709         if(!rc)
 710                 goto out;
 711         debug_register_view(rc, &debug_level_view);
 712         debug_register_view(rc, &debug_flush_view);
 713         debug_register_view(rc, &debug_pages_view);
 714 out:
 715         if (!rc){
 716                 pr_err("Registering debug feature %s failed\n", name);
 717         }
 718         mutex_unlock(&debug_mutex);
 719         return rc;
 720 }
 721 EXPORT_SYMBOL(debug_register_mode);
 722
 723 /*
 724  * debug_register:
 725  * - creates and initializes debug area for the caller
 726  * - returns handle for debug area
 727  */
 728
 729 debug_info_t *debug_register(const char *name, int pages_per_area,
 730                              int nr_areas, int buf_size)
 731 {
 732         return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
 733                                    S_IRUSR | S_IWUSR, 0, 0);
 734 }
 735 EXPORT_SYMBOL(debug_register);
 736
 737 /*
 738  * debug_unregister:
 739  * - give back debug area
 740  */
 741
 742 void
 743 debug_unregister(debug_info_t * id)
 744 {
 745         if (!id)
 746                 goto out;
 747         mutex_lock(&debug_mutex);
 748         debug_info_put(id);
 749         mutex_unlock(&debug_mutex);
 750
 751 out:
 752         return;
 753 }
 754 EXPORT_SYMBOL(debug_unregister);
 755
 756 /*
 757  * debug_set_size:
 758  * - set area size (number of pages) and number of areas
 759  */
 760 static int
 761 debug_set_size(debug_info_t* id, int nr_areas, int pages_per_area)
 762 {
 763         unsigned long flags;
 764         debug_entry_t *** new_areas;
 765         int rc=0;
 766
 767         if(!id || (nr_areas <= 0) || (pages_per_area < 0))
 768                 return -EINVAL;
 769         if(pages_per_area > 0){
 770                 new_areas = debug_areas_alloc(pages_per_area, nr_areas);
 771                 if(!new_areas) {
 772                         pr_info("Allocating memory for %i pages failed\n",
 773                                 pages_per_area);
 774                         rc = -ENOMEM;
 775                         goto out;
 776                 }
 777         } else {
 778                 new_areas = NULL;
 779         }
 780         spin_lock_irqsave(&id->lock,flags);
 781         debug_areas_free(id);
 782         id->areas = new_areas;
 783         id->nr_areas = nr_areas;
 784         id->pages_per_area = pages_per_area;
 785         id->active_area = 0;
 786         memset(id->active_entries,0,sizeof(int)*id->nr_areas);
 787         memset(id->active_pages, 0, sizeof(int)*id->nr_areas);
 788         spin_unlock_irqrestore(&id->lock,flags);
 789         pr_info("%s: set new size (%i pages)\n" ,id->name, pages_per_area);
 790 out:
 791         return rc;
 792 }
 793
 794 /*
 795  * debug_set_level:
 796  * - set actual debug level
 797  */
 798
 799 void
 800 debug_set_level(debug_info_t* id, int new_level)
 801 {
 802         unsigned long flags;
 803         if(!id)
 804                 return;
 805         spin_lock_irqsave(&id->lock,flags);
 806         if(new_level == DEBUG_OFF_LEVEL){
 807                 id->level = DEBUG_OFF_LEVEL;
 808                 pr_info("%s: switched off\n",id->name);
 809         } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
 810                 pr_info("%s: level %i is out of range (%i - %i)\n",
 811                         id->name, new_level, 0, DEBUG_MAX_LEVEL);
 812         } else {
 813                 id->level = new_level;
 814         }
 815         spin_unlock_irqrestore(&id->lock,flags);
 816 }
 817 EXPORT_SYMBOL(debug_set_level);
 818
 819 /*
 820  * proceed_active_entry:
 821  * - set active entry to next in the ring buffer
 822  */
 823
 824 static inline void
 825 proceed_active_entry(debug_info_t * id)
 826 {
 827         if ((id->active_entries[id->active_area] += id->entry_size)
 828             > (PAGE_SIZE - id->entry_size)){
 829                 id->active_entries[id->active_area] = 0;
 830                 id->active_pages[id->active_area] =
 831                         (id->active_pages[id->active_area] + 1) %
 832                         id->pages_per_area;
 833         }
 834 }
 835
 836 /*
 837  * proceed_active_area:
 838  * - set active area to next in the ring buffer
 839  */
 840
 841 static inline void
 842 proceed_active_area(debug_info_t * id)
 843 {
 844         id->active_area++;
 845         id->active_area = id->active_area % id->nr_areas;
 846 }
 847
 848 /*
 849  * get_active_entry:
 850  */
 851
 852 static inline debug_entry_t*
 853 get_active_entry(debug_info_t * id)
 854 {
 855         return (debug_entry_t *) (((char *) id->areas[id->active_area]
 856                                         [id->active_pages[id->active_area]]) +
 857                                         id->active_entries[id->active_area]);
 858 }
 859
 860 /*
 861  * debug_finish_entry:
 862  * - set timestamp, caller address, cpu number etc.
 863  */
 864
 865 static inline void
 866 debug_finish_entry(debug_info_t * id, debug_entry_t* active, int level,
 867                         int exception)
 868 {
 869         active->id.stck = get_tod_clock_fast() - sched_clock_base_cc;
 870         active->id.fields.cpuid = smp_processor_id();
 871         active->caller = __builtin_return_address(0);
 872         active->id.fields.exception = exception;
 873         active->id.fields.level     = level;
 874         proceed_active_entry(id);
 875         if(exception)
 876                 proceed_active_area(id);
 877 }
 878
 879 static int debug_stoppable=1;
 880 static int debug_active=1;
 881
 882 #define CTL_S390DBF_STOPPABLE 5678
 883 #define CTL_S390DBF_ACTIVE 5679
 884
 885 /*
 886  * proc handler for the running debug_active sysctl
 887  * always allow read, allow write only if debug_stoppable is set or
 888  * if debug_active is already off
 889  */
 890 static int
 891 s390dbf_procactive(struct ctl_table *table, int write,
 892                      void __user *buffer, size_t *lenp, loff_t *ppos)
 893 {
 894         if (!write || debug_stoppable || !debug_active)
 895                 return proc_dointvec(table, write, buffer, lenp, ppos);
 896         else
 897                 return 0;
 898 }
 899
 900
 901 static struct ctl_table s390dbf_table[] = {
 902         {
 903                 .procname       = "debug_stoppable",
 904                 .data           = &debug_stoppable,
 905                 .maxlen         = sizeof(int),
 906                 .mode           = S_IRUGO | S_IWUSR,
 907                 .proc_handler   = proc_dointvec,
 908         },
 909          {
 910                 .procname       = "debug_active",
 911                 .data           = &debug_active,
 912                 .maxlen         = sizeof(int),
 913                 .mode           = S_IRUGO | S_IWUSR,
 914                 .proc_handler   = s390dbf_procactive,
 915         },
 916         { }
 917 };
 918
 919 static struct ctl_table s390dbf_dir_table[] = {
 920         {
 921                 .procname       = "s390dbf",
 922                 .maxlen         = 0,
 923                 .mode           = S_IRUGO | S_IXUGO,
 924                 .child          = s390dbf_table,
 925         },
 926         { }
 927 };
 928
 929 static struct ctl_table_header *s390dbf_sysctl_header;
 930
 931 void
 932 debug_stop_all(void)
 933 {
 934         if (debug_stoppable)
 935                 debug_active = 0;
 936 }
 937 EXPORT_SYMBOL(debug_stop_all);
 938
 939 void debug_set_critical(void)
 940 {
 941         debug_critical = 1;
 942 }
 943
 944 /*
 945  * debug_event_common:
 946  * - write debug entry with given size
 947  */
 948
 949 debug_entry_t*
 950 debug_event_common(debug_info_t * id, int level, const void *buf, int len)
 951 {
 952         unsigned long flags;
 953         debug_entry_t *active;
 954
 955         if (!debug_active || !id->areas)
 956                 return NULL;
 957         if (debug_critical) {
 958                 if (!spin_trylock_irqsave(&id->lock, flags))
 959                         return NULL;
 960         } else
 961                 spin_lock_irqsave(&id->lock, flags);
 962         active = get_active_entry(id);
 963         memset(DEBUG_DATA(active), 0, id->buf_size);
 964         memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
 965         debug_finish_entry(id, active, level, 0);
 966         spin_unlock_irqrestore(&id->lock, flags);
 967
 968         return active;
 969 }
 970 EXPORT_SYMBOL(debug_event_common);
 971
 972 /*
 973  * debug_exception_common:
 974  * - write debug entry with given size and switch to next debug area
 975  */
 976
 977 debug_entry_t
 978 *debug_exception_common(debug_info_t * id, int level, const void *buf, int len)
 979 {
 980         unsigned long flags;
 981         debug_entry_t *active;
 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         active = get_active_entry(id);
 991         memset(DEBUG_DATA(active), 0, id->buf_size);
 992         memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
 993         debug_finish_entry(id, active, level, 1);
 994         spin_unlock_irqrestore(&id->lock, flags);
 995
 996         return active;
 997 }
 998 EXPORT_SYMBOL(debug_exception_common);
 999
1000 /*
1001  * counts arguments in format string for sprintf view
1002  */
1003
1004 static inline int
1005 debug_count_numargs(char *string)
1006 {
1007         int numargs=0;
1008
1009         while(*string) {
1010                 if(*string++=='%')
1011                         numargs++;
1012         }
1013         return(numargs);
1014 }
1015
1016 /*
1017  * debug_sprintf_event:
1018  */
1019
1020 debug_entry_t*
1021 __debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
1022 {
1023         va_list   ap;
1024         int numargs,idx;
1025         unsigned long flags;
1026         debug_sprintf_entry_t *curr_event;
1027         debug_entry_t *active;
1028
1029         if (!debug_active || !id->areas)
1030                 return NULL;
1031         numargs=debug_count_numargs(string);
1032
1033         if (debug_critical) {
1034                 if (!spin_trylock_irqsave(&id->lock, flags))
1035                         return NULL;
1036         } else
1037                 spin_lock_irqsave(&id->lock, flags);
1038         active = get_active_entry(id);
1039         curr_event=(debug_sprintf_entry_t *) DEBUG_DATA(active);
1040         va_start(ap,string);
1041         curr_event->string=string;
1042         for(idx=0;idx<min(numargs,(int)(id->buf_size / sizeof(long))-1);idx++)
1043                 curr_event->args[idx]=va_arg(ap,long);
1044         va_end(ap);
1045         debug_finish_entry(id, active, level, 0);
1046         spin_unlock_irqrestore(&id->lock, flags);
1047
1048         return active;
1049 }
1050 EXPORT_SYMBOL(__debug_sprintf_event);
1051
1052 /*
1053  * debug_sprintf_exception:
1054  */
1055
1056 debug_entry_t*
1057 __debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1058 {
1059         va_list   ap;
1060         int numargs,idx;
1061         unsigned long flags;
1062         debug_sprintf_entry_t *curr_event;
1063         debug_entry_t *active;
1064
1065         if (!debug_active || !id->areas)
1066                 return NULL;
1067
1068         numargs=debug_count_numargs(string);
1069
1070         if (debug_critical) {
1071                 if (!spin_trylock_irqsave(&id->lock, flags))
1072                         return NULL;
1073         } else
1074                 spin_lock_irqsave(&id->lock, flags);
1075         active = get_active_entry(id);
1076         curr_event=(debug_sprintf_entry_t *)DEBUG_DATA(active);
1077         va_start(ap,string);
1078         curr_event->string=string;
1079         for(idx=0;idx<min(numargs,(int)(id->buf_size / sizeof(long))-1);idx++)
1080                 curr_event->args[idx]=va_arg(ap,long);
1081         va_end(ap);
1082         debug_finish_entry(id, active, level, 1);
1083         spin_unlock_irqrestore(&id->lock, flags);
1084
1085         return active;
1086 }
1087 EXPORT_SYMBOL(__debug_sprintf_exception);
1088
1089 /*
1090  * debug_register_view:
1091  */
1092
1093 int
1094 debug_register_view(debug_info_t * id, struct debug_view *view)
1095 {
1096         int rc = 0;
1097         int i;
1098         unsigned long flags;
1099         umode_t mode;
1100         struct dentry *pde;
1101
1102         if (!id)
1103                 goto out;
1104         mode = (id->mode | S_IFREG) & ~S_IXUGO;
1105         if (!(view->prolog_proc || view->format_proc || view->header_proc))
1106                 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1107         if (!view->input_proc)
1108                 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1109         pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1110                                 id , &debug_file_ops);
1111         if (!pde){
1112                 pr_err("Registering view %s/%s failed due to out of "
1113                        "memory\n", id->name,view->name);
1114                 rc = -1;
1115                 goto out;
1116         }
1117         spin_lock_irqsave(&id->lock, flags);
1118         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1119                 if (!id->views[i])
1120                         break;
1121         }
1122         if (i == DEBUG_MAX_VIEWS) {
1123                 pr_err("Registering view %s/%s would exceed the maximum "
1124                        "number of views %i\n", id->name, view->name, i);
1125                 rc = -1;
1126         } else {
1127                 id->views[i] = view;
1128                 id->debugfs_entries[i] = pde;
1129         }
1130         spin_unlock_irqrestore(&id->lock, flags);
1131         if (rc)
1132                 debugfs_remove(pde);
1133 out:
1134         return rc;
1135 }
1136 EXPORT_SYMBOL(debug_register_view);
1137
1138 /*
1139  * debug_unregister_view:
1140  */
1141
1142 int
1143 debug_unregister_view(debug_info_t * id, struct debug_view *view)
1144 {
1145         struct dentry *dentry = NULL;
1146         unsigned long flags;
1147         int i, rc = 0;
1148
1149         if (!id)
1150                 goto out;
1151         spin_lock_irqsave(&id->lock, flags);
1152         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1153                 if (id->views[i] == view)
1154                         break;
1155         }
1156         if (i == DEBUG_MAX_VIEWS)
1157                 rc = -1;
1158         else {
1159                 dentry = id->debugfs_entries[i];
1160                 id->views[i] = NULL;
1161                 id->debugfs_entries[i] = NULL;
1162         }
1163         spin_unlock_irqrestore(&id->lock, flags);
1164         debugfs_remove(dentry);
1165 out:
1166         return rc;
1167 }
1168 EXPORT_SYMBOL(debug_unregister_view);
1169
1170 static inline char *
1171 debug_get_user_string(const char __user *user_buf, size_t user_len)
1172 {
1173         char* buffer;
1174
1175         buffer = kmalloc(user_len + 1, GFP_KERNEL);
1176         if (!buffer)
1177                 return ERR_PTR(-ENOMEM);
1178         if (copy_from_user(buffer, user_buf, user_len) != 0) {
1179                 kfree(buffer);
1180                 return ERR_PTR(-EFAULT);
1181         }
1182         /* got the string, now strip linefeed. */
1183         if (buffer[user_len - 1] == '\n')
1184                 buffer[user_len - 1] = 0;
1185         else
1186                 buffer[user_len] = 0;
1187         return buffer;
1188 }
1189
1190 static inline int
1191 debug_get_uint(char *buf)
1192 {
1193         int rc;
1194
1195         buf = skip_spaces(buf);
1196         rc = simple_strtoul(buf, &buf, 10);
1197         if(*buf){
1198                 rc = -EINVAL;
1199         }
1200         return rc;
1201 }
1202
1203 /*
1204  * functions for debug-views
1205  ***********************************
1206 */
1207
1208 /*
1209  * prints out actual debug level
1210  */
1211
1212 static int
1213 debug_prolog_pages_fn(debug_info_t * id,
1214                                  struct debug_view *view, char *out_buf)
1215 {
1216         return sprintf(out_buf, "%i\n", id->pages_per_area);
1217 }
1218
1219 /*
1220  * reads new size (number of pages per debug area)
1221  */
1222
1223 static int
1224 debug_input_pages_fn(debug_info_t * id, struct debug_view *view,
1225                         struct file *file, const char __user *user_buf,
1226                         size_t user_len, loff_t * offset)
1227 {
1228         char *str;
1229         int rc,new_pages;
1230
1231         if (user_len > 0x10000)
1232                 user_len = 0x10000;
1233         if (*offset != 0){
1234                 rc = -EPIPE;
1235                 goto out;
1236         }
1237         str = debug_get_user_string(user_buf,user_len);
1238         if(IS_ERR(str)){
1239                 rc = PTR_ERR(str);
1240                 goto out;
1241         }
1242         new_pages = debug_get_uint(str);
1243         if(new_pages < 0){
1244                 rc = -EINVAL;
1245                 goto free_str;
1246         }
1247         rc = debug_set_size(id,id->nr_areas, new_pages);
1248         if(rc != 0){
1249                 rc = -EINVAL;
1250                 goto free_str;
1251         }
1252         rc = user_len;
1253 free_str:
1254         kfree(str);
1255 out:
1256         *offset += user_len;
1257         return rc;              /* number of input characters */
1258 }
1259
1260 /*
1261  * prints out actual debug level
1262  */
1263
1264 static int
1265 debug_prolog_level_fn(debug_info_t * id, struct debug_view *view, char *out_buf)
1266 {
1267         int rc = 0;
1268
1269         if(id->level == DEBUG_OFF_LEVEL) {
1270                 rc = sprintf(out_buf,"-\n");
1271         }
1272         else {
1273                 rc = sprintf(out_buf, "%i\n", id->level);
1274         }
1275         return rc;
1276 }
1277
1278 /*
1279  * reads new debug level
1280  */
1281
1282 static int
1283 debug_input_level_fn(debug_info_t * id, struct debug_view *view,
1284                         struct file *file, const char __user *user_buf,
1285                         size_t user_len, loff_t * offset)
1286 {
1287         char *str;
1288         int rc,new_level;
1289
1290         if (user_len > 0x10000)
1291                 user_len = 0x10000;
1292         if (*offset != 0){
1293                 rc = -EPIPE;
1294                 goto out;
1295         }
1296         str = debug_get_user_string(user_buf,user_len);
1297         if(IS_ERR(str)){
1298                 rc = PTR_ERR(str);
1299                 goto out;
1300         }
1301         if(str[0] == '-'){
1302                 debug_set_level(id, DEBUG_OFF_LEVEL);
1303                 rc = user_len;
1304                 goto free_str;
1305         } else {
1306                 new_level = debug_get_uint(str);
1307         }
1308         if(new_level < 0) {
1309                 pr_warn("%s is not a valid level for a debug feature\n", str);
1310                 rc = -EINVAL;
1311         } else {
1312                 debug_set_level(id, new_level);
1313                 rc = user_len;
1314         }
1315 free_str:
1316         kfree(str);
1317 out:
1318         *offset += user_len;
1319         return rc;              /* number of input characters */
1320 }
1321
1322
1323 /*
1324  * flushes debug areas
1325  */
1326
1327 static void debug_flush(debug_info_t* id, int area)
1328 {
1329         unsigned long flags;
1330         int i,j;
1331
1332         if(!id || !id->areas)
1333                 return;
1334         spin_lock_irqsave(&id->lock,flags);
1335         if(area == DEBUG_FLUSH_ALL){
1336                 id->active_area = 0;
1337                 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1338                 for (i = 0; i < id->nr_areas; i++) {
1339                         id->active_pages[i] = 0;
1340                         for(j = 0; j < id->pages_per_area; j++) {
1341                                 memset(id->areas[i][j], 0, PAGE_SIZE);
1342                         }
1343                 }
1344         } else if(area >= 0 && area < id->nr_areas) {
1345                 id->active_entries[area] = 0;
1346                 id->active_pages[area] = 0;
1347                 for(i = 0; i < id->pages_per_area; i++) {
1348                         memset(id->areas[area][i],0,PAGE_SIZE);
1349                 }
1350         }
1351         spin_unlock_irqrestore(&id->lock,flags);
1352 }
1353
1354 /*
1355  * view function: flushes debug areas
1356  */
1357
1358 static int
1359 debug_input_flush_fn(debug_info_t * id, struct debug_view *view,
1360                         struct file *file, const char __user *user_buf,
1361                         size_t user_len, loff_t * offset)
1362 {
1363         char input_buf[1];
1364         int rc = user_len;
1365
1366         if (user_len > 0x10000)
1367                 user_len = 0x10000;
1368         if (*offset != 0){
1369                 rc = -EPIPE;
1370                 goto out;
1371         }
1372         if (copy_from_user(input_buf, user_buf, 1)){
1373                 rc = -EFAULT;
1374                 goto out;
1375         }
1376         if(input_buf[0] == '-') {
1377                 debug_flush(id, DEBUG_FLUSH_ALL);
1378                 goto out;
1379         }
1380         if (isdigit(input_buf[0])) {
1381                 int area = ((int) input_buf[0] - (int) '0');
1382                 debug_flush(id, area);
1383                 goto out;
1384         }
1385
1386         pr_info("Flushing debug data failed because %c is not a valid "
1387                  "area\n", input_buf[0]);
1388
1389 out:
1390         *offset += user_len;
1391         return rc;              /* number of input characters */
1392 }
1393
1394 /*
1395  * prints debug header in raw format
1396  */
1397
1398 static int
1399 debug_raw_header_fn(debug_info_t * id, struct debug_view *view,
1400                         int area, debug_entry_t * entry, char *out_buf)
1401 {
1402         int rc;
1403
1404         rc = sizeof(debug_entry_t);
1405         memcpy(out_buf,entry,sizeof(debug_entry_t));
1406         return rc;
1407 }
1408
1409 /*
1410  * prints debug data in raw format
1411  */
1412
1413 static int
1414 debug_raw_format_fn(debug_info_t * id, struct debug_view *view,
1415                                char *out_buf, const char *in_buf)
1416 {
1417         int rc;
1418
1419         rc = id->buf_size;
1420         memcpy(out_buf, in_buf, id->buf_size);
1421         return rc;
1422 }
1423
1424 /*
1425  * prints debug data in hex/ascii format
1426  */
1427
1428 static int
1429 debug_hex_ascii_format_fn(debug_info_t * id, struct debug_view *view,
1430                           char *out_buf, const char *in_buf)
1431 {
1432         int i, rc = 0;
1433
1434         for (i = 0; i < id->buf_size; i++) {
1435                 rc += sprintf(out_buf + rc, "%02x ",
1436                               ((unsigned char *) in_buf)[i]);
1437         }
1438         rc += sprintf(out_buf + rc, "| ");
1439         for (i = 0; i < id->buf_size; i++) {
1440                 unsigned char c = in_buf[i];
1441                 if (isascii(c) && isprint(c))
1442                         rc += sprintf(out_buf + rc, "%c", c);
1443                 else
1444                         rc += sprintf(out_buf + rc, ".");
1445         }
1446         rc += sprintf(out_buf + rc, "\n");
1447         return rc;
1448 }
1449
1450 /*
1451  * prints header for debug entry
1452  */
1453
1454 int
1455 debug_dflt_header_fn(debug_info_t * id, struct debug_view *view,
1456                          int area, debug_entry_t * entry, char *out_buf)
1457 {
1458         unsigned long sec, usec;
1459         char *except_str;
1460         unsigned long caller;
1461         int rc = 0;
1462         unsigned int level;
1463
1464         level = entry->id.fields.level;
1465         sec = (entry->id.stck >> 12) + (sched_clock_base_cc >> 12);
1466         sec = sec - (TOD_UNIX_EPOCH >> 12);
1467         usec = do_div(sec, USEC_PER_SEC);
1468
1469         if (entry->id.fields.exception)
1470                 except_str = "*";
1471         else
1472                 except_str = "-";
1473         caller = (unsigned long) entry->caller;
1474         rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %02i %p  ",
1475                       area, sec, usec, level, except_str,
1476                       entry->id.fields.cpuid, (void *)caller);
1477         return rc;
1478 }
1479 EXPORT_SYMBOL(debug_dflt_header_fn);
1480
1481 /*
1482  * prints debug data sprintf-formated:
1483  * debug_sprinf_event/exception calls must be used together with this view
1484  */
1485
1486 #define DEBUG_SPRINTF_MAX_ARGS 10
1487
1488 static int
1489 debug_sprintf_format_fn(debug_info_t * id, struct debug_view *view,
1490                         char *out_buf, debug_sprintf_entry_t *curr_event)
1491 {
1492         int num_longs, num_used_args = 0,i, rc = 0;
1493         int index[DEBUG_SPRINTF_MAX_ARGS];
1494
1495         /* count of longs fit into one entry */
1496         num_longs = id->buf_size /  sizeof(long);
1497
1498         if(num_longs < 1)
1499                 goto out; /* bufsize of entry too small */
1500         if(num_longs == 1) {
1501                 /* no args, we use only the string */
1502                 strcpy(out_buf, curr_event->string);
1503                 rc = strlen(curr_event->string);
1504                 goto out;
1505         }
1506
1507         /* number of arguments used for sprintf (without the format string) */
1508         num_used_args   = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1509
1510         memset(index,0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1511
1512         for(i = 0; i < num_used_args; i++)
1513                 index[i] = i;
1514
1515         rc =  sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1516                 curr_event->args[index[1]], curr_event->args[index[2]],
1517                 curr_event->args[index[3]], curr_event->args[index[4]],
1518                 curr_event->args[index[5]], curr_event->args[index[6]],
1519                 curr_event->args[index[7]], curr_event->args[index[8]],
1520                 curr_event->args[index[9]]);
1521
1522 out:
1523
1524         return rc;
1525 }
1526
1527 /*
1528  * debug_init:
1529  * - is called exactly once to initialize the debug feature
1530  */
1531 static int __init debug_init(void)
1532 {
1533         s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
1534         mutex_lock(&debug_mutex);
1535         debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1536         initialized = 1;
1537         mutex_unlock(&debug_mutex);
1538         return 0;
1539 }
1540 postcore_initcall(debug_init);