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:
 653  * - Creates and initializes debug area for the caller
 654  *   The mode parameter allows to specify access rights for the s390dbf files
 655  * - Returns handle for debug area
 656  */
 657 debug_info_t *debug_register_mode(const char *name, int pages_per_area,
 658                                   int nr_areas, int buf_size, umode_t mode,
 659                                   uid_t uid, gid_t gid)
 660 {
 661         debug_info_t *rc = NULL;
 662
 663         /* Since debugfs currently does not support uid/gid other than root, */
 664         /* we do not allow gid/uid != 0 until we get support for that. */
 665         if ((uid != 0) || (gid != 0))
 666                 pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
 667         BUG_ON(!initialized);
 668         mutex_lock(&debug_mutex);
 669
 670         /* create new debug_info */
 671         rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
 672         if (!rc)
 673                 goto out;
 674         debug_register_view(rc, &debug_level_view);
 675         debug_register_view(rc, &debug_flush_view);
 676         debug_register_view(rc, &debug_pages_view);
 677 out:
 678         if (!rc)
 679                 pr_err("Registering debug feature %s failed\n", name);
 680         mutex_unlock(&debug_mutex);
 681         return rc;
 682 }
 683 EXPORT_SYMBOL(debug_register_mode);
 684
 685 /*
 686  * debug_register:
 687  * - creates and initializes debug area for the caller
 688  * - returns handle for debug area
 689  */
 690 debug_info_t *debug_register(const char *name, int pages_per_area,
 691                              int nr_areas, int buf_size)
 692 {
 693         return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
 694                                    S_IRUSR | S_IWUSR, 0, 0);
 695 }
 696 EXPORT_SYMBOL(debug_register);
 697
 698 /*
 699  * debug_unregister:
 700  * - give back debug area
 701  */
 702 void debug_unregister(debug_info_t *id)
 703 {
 704         if (!id)
 705                 return;
 706         mutex_lock(&debug_mutex);
 707         debug_info_put(id);
 708         mutex_unlock(&debug_mutex);
 709 }
 710 EXPORT_SYMBOL(debug_unregister);
 711
 712 /*
 713  * debug_set_size:
 714  * - set area size (number of pages) and number of areas
 715  */
 716 static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
 717 {
 718         debug_entry_t ***new_areas;
 719         unsigned long flags;
 720         int rc = 0;
 721
 722         if (!id || (nr_areas <= 0) || (pages_per_area < 0))
 723                 return -EINVAL;
 724         if (pages_per_area > 0) {
 725                 new_areas = debug_areas_alloc(pages_per_area, nr_areas);
 726                 if (!new_areas) {
 727                         pr_info("Allocating memory for %i pages failed\n",
 728                                 pages_per_area);
 729                         rc = -ENOMEM;
 730                         goto out;
 731                 }
 732         } else {
 733                 new_areas = NULL;
 734         }
 735         spin_lock_irqsave(&id->lock, flags);
 736         debug_areas_free(id);
 737         id->areas = new_areas;
 738         id->nr_areas = nr_areas;
 739         id->pages_per_area = pages_per_area;
 740         id->active_area = 0;
 741         memset(id->active_entries, 0, sizeof(int)*id->nr_areas);
 742         memset(id->active_pages, 0, sizeof(int)*id->nr_areas);
 743         spin_unlock_irqrestore(&id->lock, flags);
 744         pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
 745 out:
 746         return rc;
 747 }
 748
 749 /*
 750  * debug_set_level:
 751  * - set actual debug level
 752  */
 753 void debug_set_level(debug_info_t *id, int new_level)
 754 {
 755         unsigned long flags;
 756
 757         if (!id)
 758                 return;
 759         spin_lock_irqsave(&id->lock, flags);
 760         if (new_level == DEBUG_OFF_LEVEL) {
 761                 id->level = DEBUG_OFF_LEVEL;
 762                 pr_info("%s: switched off\n", id->name);
 763         } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
 764                 pr_info("%s: level %i is out of range (%i - %i)\n",
 765                         id->name, new_level, 0, DEBUG_MAX_LEVEL);
 766         } else {
 767                 id->level = new_level;
 768         }
 769         spin_unlock_irqrestore(&id->lock, flags);
 770 }
 771 EXPORT_SYMBOL(debug_set_level);
 772
 773 /*
 774  * proceed_active_entry:
 775  * - set active entry to next in the ring buffer
 776  */
 777 static inline void proceed_active_entry(debug_info_t *id)
 778 {
 779         if ((id->active_entries[id->active_area] += id->entry_size)
 780             > (PAGE_SIZE - id->entry_size)) {
 781                 id->active_entries[id->active_area] = 0;
 782                 id->active_pages[id->active_area] =
 783                         (id->active_pages[id->active_area] + 1) %
 784                         id->pages_per_area;
 785         }
 786 }
 787
 788 /*
 789  * proceed_active_area:
 790  * - set active area to next in the ring buffer
 791  */
 792 static inline void proceed_active_area(debug_info_t *id)
 793 {
 794         id->active_area++;
 795         id->active_area = id->active_area % id->nr_areas;
 796 }
 797
 798 /*
 799  * get_active_entry:
 800  */
 801 static inline debug_entry_t *get_active_entry(debug_info_t *id)
 802 {
 803         return (debug_entry_t *) (((char *) id->areas[id->active_area]
 804                                    [id->active_pages[id->active_area]]) +
 805                                   id->active_entries[id->active_area]);
 806 }
 807
 808 /*
 809  * debug_finish_entry:
 810  * - set timestamp, caller address, cpu number etc.
 811  */
 812
 813 static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
 814                                       int level, int exception)
 815 {
 816         active->id.stck = get_tod_clock_fast() -
 817                 *(unsigned long long *) &tod_clock_base[1];
 818         active->id.fields.cpuid = smp_processor_id();
 819         active->caller = __builtin_return_address(0);
 820         active->id.fields.exception = exception;
 821         active->id.fields.level = level;
 822         proceed_active_entry(id);
 823         if (exception)
 824                 proceed_active_area(id);
 825 }
 826
 827 static int debug_stoppable = 1;
 828 static int debug_active = 1;
 829
 830 #define CTL_S390DBF_STOPPABLE 5678
 831 #define CTL_S390DBF_ACTIVE 5679
 832
 833 /*
 834  * proc handler for the running debug_active sysctl
 835  * always allow read, allow write only if debug_stoppable is set or
 836  * if debug_active is already off
 837  */
 838 static int s390dbf_procactive(struct ctl_table *table, int write,
 839                               void __user *buffer, size_t *lenp, loff_t *ppos)
 840 {
 841         if (!write || debug_stoppable || !debug_active)
 842                 return proc_dointvec(table, write, buffer, lenp, ppos);
 843         else
 844                 return 0;
 845 }
 846
 847 static struct ctl_table s390dbf_table[] = {
 848         {
 849                 .procname       = "debug_stoppable",
 850                 .data           = &debug_stoppable,
 851                 .maxlen         = sizeof(int),
 852                 .mode           = S_IRUGO | S_IWUSR,
 853                 .proc_handler   = proc_dointvec,
 854         },
 855         {
 856                 .procname       = "debug_active",
 857                 .data           = &debug_active,
 858                 .maxlen         = sizeof(int),
 859                 .mode           = S_IRUGO | S_IWUSR,
 860                 .proc_handler   = s390dbf_procactive,
 861         },
 862         { }
 863 };
 864
 865 static struct ctl_table s390dbf_dir_table[] = {
 866         {
 867                 .procname       = "s390dbf",
 868                 .maxlen         = 0,
 869                 .mode           = S_IRUGO | S_IXUGO,
 870                 .child          = s390dbf_table,
 871         },
 872         { }
 873 };
 874
 875 static struct ctl_table_header *s390dbf_sysctl_header;
 876
 877 void debug_stop_all(void)
 878 {
 879         if (debug_stoppable)
 880                 debug_active = 0;
 881 }
 882 EXPORT_SYMBOL(debug_stop_all);
 883
 884 void debug_set_critical(void)
 885 {
 886         debug_critical = 1;
 887 }
 888
 889 /*
 890  * debug_event_common:
 891  * - write debug entry with given size
 892  */
 893 debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
 894                                   int len)
 895 {
 896         debug_entry_t *active;
 897         unsigned long flags;
 898
 899         if (!debug_active || !id->areas)
 900                 return NULL;
 901         if (debug_critical) {
 902                 if (!spin_trylock_irqsave(&id->lock, flags))
 903                         return NULL;
 904         } else {
 905                 spin_lock_irqsave(&id->lock, flags);
 906         }
 907         do {
 908                 active = get_active_entry(id);
 909                 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
 910                 if (len < id->buf_size)
 911                         memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
 912                 debug_finish_entry(id, active, level, 0);
 913                 len -= id->buf_size;
 914                 buf += id->buf_size;
 915         } while (len > 0);
 916
 917         spin_unlock_irqrestore(&id->lock, flags);
 918         return active;
 919 }
 920 EXPORT_SYMBOL(debug_event_common);
 921
 922 /*
 923  * debug_exception_common:
 924  * - write debug entry with given size and switch to next debug area
 925  */
 926 debug_entry_t *debug_exception_common(debug_info_t *id, int level,
 927                                       const void *buf, int len)
 928 {
 929         debug_entry_t *active;
 930         unsigned long flags;
 931
 932         if (!debug_active || !id->areas)
 933                 return NULL;
 934         if (debug_critical) {
 935                 if (!spin_trylock_irqsave(&id->lock, flags))
 936                         return NULL;
 937         } else {
 938                 spin_lock_irqsave(&id->lock, flags);
 939         }
 940         do {
 941                 active = get_active_entry(id);
 942                 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
 943                 if (len < id->buf_size)
 944                         memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
 945                 debug_finish_entry(id, active, level, len <= id->buf_size);
 946                 len -= id->buf_size;
 947                 buf += id->buf_size;
 948         } while (len > 0);
 949
 950         spin_unlock_irqrestore(&id->lock, flags);
 951         return active;
 952 }
 953 EXPORT_SYMBOL(debug_exception_common);
 954
 955 /*
 956  * counts arguments in format string for sprintf view
 957  */
 958 static inline int debug_count_numargs(char *string)
 959 {
 960         int numargs = 0;
 961
 962         while (*string) {
 963                 if (*string++ == '%')
 964                         numargs++;
 965         }
 966         return numargs;
 967 }
 968
 969 /*
 970  * debug_sprintf_event:
 971  */
 972 debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
 973 {
 974         debug_sprintf_entry_t *curr_event;
 975         debug_entry_t *active;
 976         unsigned long flags;
 977         int numargs, idx;
 978         va_list ap;
 979
 980         if (!debug_active || !id->areas)
 981                 return NULL;
 982         numargs = debug_count_numargs(string);
 983
 984         if (debug_critical) {
 985                 if (!spin_trylock_irqsave(&id->lock, flags))
 986                         return NULL;
 987         } else {
 988                 spin_lock_irqsave(&id->lock, flags);
 989         }
 990         active = get_active_entry(id);
 991         curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
 992         va_start(ap, string);
 993         curr_event->string = string;
 994         for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
 995                 curr_event->args[idx] = va_arg(ap, long);
 996         va_end(ap);
 997         debug_finish_entry(id, active, level, 0);
 998         spin_unlock_irqrestore(&id->lock, flags);
 999
1000         return active;
1001 }
1002 EXPORT_SYMBOL(__debug_sprintf_event);
1003
1004 /*
1005  * debug_sprintf_exception:
1006  */
1007 debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1008 {
1009         debug_sprintf_entry_t *curr_event;
1010         debug_entry_t *active;
1011         unsigned long flags;
1012         int numargs, idx;
1013         va_list ap;
1014
1015         if (!debug_active || !id->areas)
1016                 return NULL;
1017
1018         numargs = debug_count_numargs(string);
1019
1020         if (debug_critical) {
1021                 if (!spin_trylock_irqsave(&id->lock, flags))
1022                         return NULL;
1023         } else {
1024                 spin_lock_irqsave(&id->lock, flags);
1025         }
1026         active = get_active_entry(id);
1027         curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
1028         va_start(ap, string);
1029         curr_event->string = string;
1030         for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1031                 curr_event->args[idx] = va_arg(ap, long);
1032         va_end(ap);
1033         debug_finish_entry(id, active, level, 1);
1034         spin_unlock_irqrestore(&id->lock, flags);
1035
1036         return active;
1037 }
1038 EXPORT_SYMBOL(__debug_sprintf_exception);
1039
1040 /*
1041  * debug_register_view:
1042  */
1043 int debug_register_view(debug_info_t *id, struct debug_view *view)
1044 {
1045         unsigned long flags;
1046         struct dentry *pde;
1047         umode_t mode;
1048         int rc = 0;
1049         int i;
1050
1051         if (!id)
1052                 goto out;
1053         mode = (id->mode | S_IFREG) & ~S_IXUGO;
1054         if (!(view->prolog_proc || view->format_proc || view->header_proc))
1055                 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1056         if (!view->input_proc)
1057                 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1058         pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1059                                   id, &debug_file_ops);
1060         if (!pde) {
1061                 pr_err("Registering view %s/%s failed due to out of "
1062                        "memory\n", id->name, view->name);
1063                 rc = -1;
1064                 goto out;
1065         }
1066         spin_lock_irqsave(&id->lock, flags);
1067         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1068                 if (!id->views[i])
1069                         break;
1070         }
1071         if (i == DEBUG_MAX_VIEWS) {
1072                 pr_err("Registering view %s/%s would exceed the maximum "
1073                        "number of views %i\n", id->name, view->name, i);
1074                 rc = -1;
1075         } else {
1076                 id->views[i] = view;
1077                 id->debugfs_entries[i] = pde;
1078         }
1079         spin_unlock_irqrestore(&id->lock, flags);
1080         if (rc)
1081                 debugfs_remove(pde);
1082 out:
1083         return rc;
1084 }
1085 EXPORT_SYMBOL(debug_register_view);
1086
1087 /*
1088  * debug_unregister_view:
1089  */
1090 int debug_unregister_view(debug_info_t *id, struct debug_view *view)
1091 {
1092         struct dentry *dentry = NULL;
1093         unsigned long flags;
1094         int i, rc = 0;
1095
1096         if (!id)
1097                 goto out;
1098         spin_lock_irqsave(&id->lock, flags);
1099         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1100                 if (id->views[i] == view)
1101                         break;
1102         }
1103         if (i == DEBUG_MAX_VIEWS) {
1104                 rc = -1;
1105         } else {
1106                 dentry = id->debugfs_entries[i];
1107                 id->views[i] = NULL;
1108                 id->debugfs_entries[i] = NULL;
1109         }
1110         spin_unlock_irqrestore(&id->lock, flags);
1111         debugfs_remove(dentry);
1112 out:
1113         return rc;
1114 }
1115 EXPORT_SYMBOL(debug_unregister_view);
1116
1117 static inline char *debug_get_user_string(const char __user *user_buf,
1118                                           size_t user_len)
1119 {
1120         char *buffer;
1121
1122         buffer = kmalloc(user_len + 1, GFP_KERNEL);
1123         if (!buffer)
1124                 return ERR_PTR(-ENOMEM);
1125         if (copy_from_user(buffer, user_buf, user_len) != 0) {
1126                 kfree(buffer);
1127                 return ERR_PTR(-EFAULT);
1128         }
1129         /* got the string, now strip linefeed. */
1130         if (buffer[user_len - 1] == '\n')
1131                 buffer[user_len - 1] = 0;
1132         else
1133                 buffer[user_len] = 0;
1134         return buffer;
1135 }
1136
1137 static inline int debug_get_uint(char *buf)
1138 {
1139         int rc;
1140
1141         buf = skip_spaces(buf);
1142         rc = simple_strtoul(buf, &buf, 10);
1143         if (*buf)
1144                 rc = -EINVAL;
1145         return rc;
1146 }
1147
1148 /*
1149  * functions for debug-views
1150  ***********************************
1151 */
1152
1153 /*
1154  * prints out actual debug level
1155  */
1156
1157 static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
1158                                  char *out_buf)
1159 {
1160         return sprintf(out_buf, "%i\n", id->pages_per_area);
1161 }
1162
1163 /*
1164  * reads new size (number of pages per debug area)
1165  */
1166
1167 static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
1168                                 struct file *file, const char __user *user_buf,
1169                                 size_t user_len, loff_t *offset)
1170 {
1171         int rc, new_pages;
1172         char *str;
1173
1174         if (user_len > 0x10000)
1175                 user_len = 0x10000;
1176         if (*offset != 0) {
1177                 rc = -EPIPE;
1178                 goto out;
1179         }
1180         str = debug_get_user_string(user_buf, user_len);
1181         if (IS_ERR(str)) {
1182                 rc = PTR_ERR(str);
1183                 goto out;
1184         }
1185         new_pages = debug_get_uint(str);
1186         if (new_pages < 0) {
1187                 rc = -EINVAL;
1188                 goto free_str;
1189         }
1190         rc = debug_set_size(id, id->nr_areas, new_pages);
1191         if (rc != 0) {
1192                 rc = -EINVAL;
1193                 goto free_str;
1194         }
1195         rc = user_len;
1196 free_str:
1197         kfree(str);
1198 out:
1199         *offset += user_len;
1200         return rc;              /* number of input characters */
1201 }
1202
1203 /*
1204  * prints out actual debug level
1205  */
1206 static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
1207                                  char *out_buf)
1208 {
1209         int rc = 0;
1210
1211         if (id->level == DEBUG_OFF_LEVEL)
1212                 rc = sprintf(out_buf, "-\n");
1213         else
1214                 rc = sprintf(out_buf, "%i\n", id->level);
1215         return rc;
1216 }
1217
1218 /*
1219  * reads new debug level
1220  */
1221 static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
1222                                 struct file *file, const char __user *user_buf,
1223                                 size_t user_len, loff_t *offset)
1224 {
1225         int rc, new_level;
1226         char *str;
1227
1228         if (user_len > 0x10000)
1229                 user_len = 0x10000;
1230         if (*offset != 0) {
1231                 rc = -EPIPE;
1232                 goto out;
1233         }
1234         str = debug_get_user_string(user_buf, user_len);
1235         if (IS_ERR(str)) {
1236                 rc = PTR_ERR(str);
1237                 goto out;
1238         }
1239         if (str[0] == '-') {
1240                 debug_set_level(id, DEBUG_OFF_LEVEL);
1241                 rc = user_len;
1242                 goto free_str;
1243         } else {
1244                 new_level = debug_get_uint(str);
1245         }
1246         if (new_level < 0) {
1247                 pr_warn("%s is not a valid level for a debug feature\n", str);
1248                 rc = -EINVAL;
1249         } else {
1250                 debug_set_level(id, new_level);
1251                 rc = user_len;
1252         }
1253 free_str:
1254         kfree(str);
1255 out:
1256         *offset += user_len;
1257         return rc;              /* number of input characters */
1258 }
1259
1260 /*
1261  * flushes debug areas
1262  */
1263 static void debug_flush(debug_info_t *id, int area)
1264 {
1265         unsigned long flags;
1266         int i, j;
1267
1268         if (!id || !id->areas)
1269                 return;
1270         spin_lock_irqsave(&id->lock, flags);
1271         if (area == DEBUG_FLUSH_ALL) {
1272                 id->active_area = 0;
1273                 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1274                 for (i = 0; i < id->nr_areas; i++) {
1275                         id->active_pages[i] = 0;
1276                         for (j = 0; j < id->pages_per_area; j++)
1277                                 memset(id->areas[i][j], 0, PAGE_SIZE);
1278                 }
1279         } else if (area >= 0 && area < id->nr_areas) {
1280                 id->active_entries[area] = 0;
1281                 id->active_pages[area] = 0;
1282                 for (i = 0; i < id->pages_per_area; i++)
1283                         memset(id->areas[area][i], 0, PAGE_SIZE);
1284         }
1285         spin_unlock_irqrestore(&id->lock, flags);
1286 }
1287
1288 /*
1289  * view function: flushes debug areas
1290  */
1291 static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
1292                                 struct file *file, const char __user *user_buf,
1293                                 size_t user_len, loff_t *offset)
1294 {
1295         char input_buf[1];
1296         int rc = user_len;
1297
1298         if (user_len > 0x10000)
1299                 user_len = 0x10000;
1300         if (*offset != 0) {
1301                 rc = -EPIPE;
1302                 goto out;
1303         }
1304         if (copy_from_user(input_buf, user_buf, 1)) {
1305                 rc = -EFAULT;
1306                 goto out;
1307         }
1308         if (input_buf[0] == '-') {
1309                 debug_flush(id, DEBUG_FLUSH_ALL);
1310                 goto out;
1311         }
1312         if (isdigit(input_buf[0])) {
1313                 int area = ((int) input_buf[0] - (int) '0');
1314
1315                 debug_flush(id, area);
1316                 goto out;
1317         }
1318
1319         pr_info("Flushing debug data failed because %c is not a valid "
1320                  "area\n", input_buf[0]);
1321
1322 out:
1323         *offset += user_len;
1324         return rc;              /* number of input characters */
1325 }
1326
1327 /*
1328  * prints debug header in raw format
1329  */
1330 static int debug_raw_header_fn(debug_info_t *id, struct debug_view *view,
1331                                int area, debug_entry_t *entry, char *out_buf)
1332 {
1333         int rc;
1334
1335         rc = sizeof(debug_entry_t);
1336         memcpy(out_buf, entry, sizeof(debug_entry_t));
1337         return rc;
1338 }
1339
1340 /*
1341  * prints debug data in raw format
1342  */
1343 static int debug_raw_format_fn(debug_info_t *id, struct debug_view *view,
1344                                char *out_buf, const char *in_buf)
1345 {
1346         int rc;
1347
1348         rc = id->buf_size;
1349         memcpy(out_buf, in_buf, id->buf_size);
1350         return rc;
1351 }
1352
1353 /*
1354  * prints debug data in hex/ascii format
1355  */
1356 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
1357                                      char *out_buf, const char *in_buf)
1358 {
1359         int i, rc = 0;
1360
1361         for (i = 0; i < id->buf_size; i++)
1362                 rc += sprintf(out_buf + rc, "%02x ", ((unsigned char *) in_buf)[i]);
1363         rc += sprintf(out_buf + rc, "| ");
1364         for (i = 0; i < id->buf_size; i++) {
1365                 unsigned char c = in_buf[i];
1366
1367                 if (isascii(c) && isprint(c))
1368                         rc += sprintf(out_buf + rc, "%c", c);
1369                 else
1370                         rc += sprintf(out_buf + rc, ".");
1371         }
1372         rc += sprintf(out_buf + rc, "\n");
1373         return rc;
1374 }
1375
1376 /*
1377  * prints header for debug entry
1378  */
1379 int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
1380                          int area, debug_entry_t *entry, char *out_buf)
1381 {
1382         unsigned long base, sec, usec;
1383         unsigned long caller;
1384         unsigned int level;
1385         char *except_str;
1386         int rc = 0;
1387
1388         level = entry->id.fields.level;
1389         base = (*(unsigned long *) &tod_clock_base[0]) >> 4;
1390         sec = (entry->id.stck >> 12) + base - (TOD_UNIX_EPOCH >> 12);
1391         usec = do_div(sec, USEC_PER_SEC);
1392
1393         if (entry->id.fields.exception)
1394                 except_str = "*";
1395         else
1396                 except_str = "-";
1397         caller = (unsigned long) entry->caller;
1398         rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %02i %pK  ",
1399                       area, sec, usec, level, except_str,
1400                       entry->id.fields.cpuid, (void *)caller);
1401         return rc;
1402 }
1403 EXPORT_SYMBOL(debug_dflt_header_fn);
1404
1405 /*
1406  * prints debug data sprintf-formated:
1407  * debug_sprinf_event/exception calls must be used together with this view
1408  */
1409
1410 #define DEBUG_SPRINTF_MAX_ARGS 10
1411
1412 static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
1413                                    char *out_buf, debug_sprintf_entry_t *curr_event)
1414 {
1415         int num_longs, num_used_args = 0, i, rc = 0;
1416         int index[DEBUG_SPRINTF_MAX_ARGS];
1417
1418         /* count of longs fit into one entry */
1419         num_longs = id->buf_size / sizeof(long);
1420
1421         if (num_longs < 1)
1422                 goto out; /* bufsize of entry too small */
1423         if (num_longs == 1) {
1424                 /* no args, we use only the string */
1425                 strcpy(out_buf, curr_event->string);
1426                 rc = strlen(curr_event->string);
1427                 goto out;
1428         }
1429
1430         /* number of arguments used for sprintf (without the format string) */
1431         num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1432
1433         memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1434
1435         for (i = 0; i < num_used_args; i++)
1436                 index[i] = i;
1437
1438         rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1439                      curr_event->args[index[1]], curr_event->args[index[2]],
1440                      curr_event->args[index[3]], curr_event->args[index[4]],
1441                      curr_event->args[index[5]], curr_event->args[index[6]],
1442                      curr_event->args[index[7]], curr_event->args[index[8]],
1443                      curr_event->args[index[9]]);
1444 out:
1445         return rc;
1446 }
1447
1448 /*
1449  * debug_init:
1450  * - is called exactly once to initialize the debug feature
1451  */
1452 static int __init debug_init(void)
1453 {
1454         s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
1455         mutex_lock(&debug_mutex);
1456         debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1457         initialized = 1;
1458         mutex_unlock(&debug_mutex);
1459         return 0;
1460 }
1461 postcore_initcall(debug_init);