arch/s390/kernel/debug.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *   S/390 debug facility
   4  *
   5  *    Copyright IBM Corp. 1999, 2020
   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/minmax.h>
  28 #include <linux/debugfs.h>
  29
  30 #include <asm/debug.h>
  31
  32 #define DEBUG_PROLOG_ENTRY -1
  33
  34 #define ALL_AREAS 0 /* copy all debug areas */
  35 #define NO_AREAS  1 /* copy no debug areas */
  36
  37 /* typedefs */
  38
  39 typedef struct file_private_info {
  40         loff_t offset;                  /* offset of last read in file */
  41         int    act_area;                /* number of last formated area */
  42         int    act_page;                /* act page in given area */
  43         int    act_entry;               /* last formated entry (offset */
  44                                         /* relative to beginning of last */
  45                                         /* formated page) */
  46         size_t act_entry_offset;        /* up to this offset we copied */
  47                                         /* in last read the last formated */
  48                                         /* entry to userland */
  49         char   temp_buf[2048];          /* buffer for output */
  50         debug_info_t *debug_info_org;   /* original debug information */
  51         debug_info_t *debug_info_snap;  /* snapshot of debug information */
  52         struct debug_view *view;        /* used view of debug info */
  53 } file_private_info_t;
  54
  55 typedef struct {
  56         char *string;
  57         /*
  58          * This assumes that all args are converted into longs
  59          * on L/390 this is the case for all types of parameter
  60          * except of floats, and long long (32 bit)
  61          *
  62          */
  63         long args[0];
  64 } debug_sprintf_entry_t;
  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_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
  95                                    char *out_buf, debug_sprintf_entry_t *curr_event);
  96 static void debug_areas_swap(debug_info_t *a, debug_info_t *b);
  97 static void debug_events_append(debug_info_t *dest, debug_info_t *src);
  98
  99 /* globals */
 100
 101 struct debug_view debug_hex_ascii_view = {
 102         "hex_ascii",
 103         NULL,
 104         &debug_dflt_header_fn,
 105         &debug_hex_ascii_format_fn,
 106         NULL,
 107         NULL
 108 };
 109 EXPORT_SYMBOL(debug_hex_ascii_view);
 110
 111 static struct debug_view debug_level_view = {
 112         "level",
 113         &debug_prolog_level_fn,
 114         NULL,
 115         NULL,
 116         &debug_input_level_fn,
 117         NULL
 118 };
 119
 120 static struct debug_view debug_pages_view = {
 121         "pages",
 122         &debug_prolog_pages_fn,
 123         NULL,
 124         NULL,
 125         &debug_input_pages_fn,
 126         NULL
 127 };
 128
 129 static struct debug_view debug_flush_view = {
 130         "flush",
 131         NULL,
 132         NULL,
 133         NULL,
 134         &debug_input_flush_fn,
 135         NULL
 136 };
 137
 138 struct debug_view debug_sprintf_view = {
 139         "sprintf",
 140         NULL,
 141         &debug_dflt_header_fn,
 142         (debug_format_proc_t *)&debug_sprintf_format_fn,
 143         NULL,
 144         NULL
 145 };
 146 EXPORT_SYMBOL(debug_sprintf_view);
 147
 148 /* used by dump analysis tools to determine version of debug feature */
 149 static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
 150
 151 /* static globals */
 152
 153 static debug_info_t *debug_area_first;
 154 static debug_info_t *debug_area_last;
 155 static DEFINE_MUTEX(debug_mutex);
 156
 157 static int initialized;
 158 static int debug_critical;
 159
 160 static const struct file_operations debug_file_ops = {
 161         .owner   = THIS_MODULE,
 162         .read    = debug_output,
 163         .write   = debug_input,
 164         .open    = debug_open,
 165         .release = debug_close,
 166         .llseek  = no_llseek,
 167 };
 168
 169 static struct dentry *debug_debugfs_root_entry;
 170
 171 /* functions */
 172
 173 /*
 174  * debug_areas_alloc
 175  * - Debug areas are implemented as a threedimensonal array:
 176  *   areas[areanumber][pagenumber][pageoffset]
 177  */
 178
 179 static debug_entry_t ***debug_areas_alloc(int pages_per_area, int nr_areas)
 180 {
 181         debug_entry_t ***areas;
 182         int i, j;
 183
 184         areas = kmalloc_array(nr_areas, sizeof(debug_entry_t **), GFP_KERNEL);
 185         if (!areas)
 186                 goto fail_malloc_areas;
 187         for (i = 0; i < nr_areas; i++) {
 188                 /* GFP_NOWARN to avoid user triggerable WARN, we handle fails */
 189                 areas[i] = kmalloc_array(pages_per_area,
 190                                          sizeof(debug_entry_t *),
 191                                          GFP_KERNEL | __GFP_NOWARN);
 192                 if (!areas[i])
 193                         goto fail_malloc_areas2;
 194                 for (j = 0; j < pages_per_area; j++) {
 195                         areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
 196                         if (!areas[i][j]) {
 197                                 for (j--; j >= 0 ; j--)
 198                                         kfree(areas[i][j]);
 199                                 kfree(areas[i]);
 200                                 goto fail_malloc_areas2;
 201                         }
 202                 }
 203         }
 204         return areas;
 205
 206 fail_malloc_areas2:
 207         for (i--; i >= 0; i--) {
 208                 for (j = 0; j < pages_per_area; j++)
 209                         kfree(areas[i][j]);
 210                 kfree(areas[i]);
 211         }
 212         kfree(areas);
 213 fail_malloc_areas:
 214         return NULL;
 215 }
 216
 217 /*
 218  * debug_info_alloc
 219  * - alloc new debug-info
 220  */
 221 static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,
 222                                       int nr_areas, int buf_size, int level,
 223                                       int mode)
 224 {
 225         debug_info_t *rc;
 226
 227         /* alloc everything */
 228         rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
 229         if (!rc)
 230                 goto fail_malloc_rc;
 231         rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
 232         if (!rc->active_entries)
 233                 goto fail_malloc_active_entries;
 234         rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
 235         if (!rc->active_pages)
 236                 goto fail_malloc_active_pages;
 237         if ((mode == ALL_AREAS) && (pages_per_area != 0)) {
 238                 rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
 239                 if (!rc->areas)
 240                         goto fail_malloc_areas;
 241         } else {
 242                 rc->areas = NULL;
 243         }
 244
 245         /* initialize members */
 246         spin_lock_init(&rc->lock);
 247         rc->pages_per_area = pages_per_area;
 248         rc->nr_areas       = nr_areas;
 249         rc->active_area    = 0;
 250         rc->level          = level;
 251         rc->buf_size       = buf_size;
 252         rc->entry_size     = sizeof(debug_entry_t) + buf_size;
 253         strlcpy(rc->name, name, sizeof(rc->name));
 254         memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
 255         memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
 256         refcount_set(&(rc->ref_count), 0);
 257
 258         return rc;
 259
 260 fail_malloc_areas:
 261         kfree(rc->active_pages);
 262 fail_malloc_active_pages:
 263         kfree(rc->active_entries);
 264 fail_malloc_active_entries:
 265         kfree(rc);
 266 fail_malloc_rc:
 267         return NULL;
 268 }
 269
 270 /*
 271  * debug_areas_free
 272  * - free all debug areas
 273  */
 274 static void debug_areas_free(debug_info_t *db_info)
 275 {
 276         int i, j;
 277
 278         if (!db_info->areas)
 279                 return;
 280         for (i = 0; i < db_info->nr_areas; i++) {
 281                 for (j = 0; j < db_info->pages_per_area; j++)
 282                         kfree(db_info->areas[i][j]);
 283                 kfree(db_info->areas[i]);
 284         }
 285         kfree(db_info->areas);
 286         db_info->areas = NULL;
 287 }
 288
 289 /*
 290  * debug_info_free
 291  * - free memory debug-info
 292  */
 293 static void debug_info_free(debug_info_t *db_info)
 294 {
 295         debug_areas_free(db_info);
 296         kfree(db_info->active_entries);
 297         kfree(db_info->active_pages);
 298         kfree(db_info);
 299 }
 300
 301 /*
 302  * debug_info_create
 303  * - create new debug-info
 304  */
 305
 306 static debug_info_t *debug_info_create(const char *name, int pages_per_area,
 307                                        int nr_areas, int buf_size, umode_t mode)
 308 {
 309         debug_info_t *rc;
 310
 311         rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
 312                               DEBUG_DEFAULT_LEVEL, ALL_AREAS);
 313         if (!rc)
 314                 goto out;
 315
 316         rc->mode = mode & ~S_IFMT;
 317         refcount_set(&rc->ref_count, 1);
 318 out:
 319         return rc;
 320 }
 321
 322 /*
 323  * debug_info_copy
 324  * - copy debug-info
 325  */
 326 static debug_info_t *debug_info_copy(debug_info_t *in, int mode)
 327 {
 328         unsigned long flags;
 329         debug_info_t *rc;
 330         int i, j;
 331
 332         /* get a consistent copy of the debug areas */
 333         do {
 334                 rc = debug_info_alloc(in->name, in->pages_per_area,
 335                         in->nr_areas, in->buf_size, in->level, mode);
 336                 spin_lock_irqsave(&in->lock, flags);
 337                 if (!rc)
 338                         goto out;
 339                 /* has something changed in the meantime ? */
 340                 if ((rc->pages_per_area == in->pages_per_area) &&
 341                     (rc->nr_areas == in->nr_areas)) {
 342                         break;
 343                 }
 344                 spin_unlock_irqrestore(&in->lock, flags);
 345                 debug_info_free(rc);
 346         } while (1);
 347
 348         if (mode == NO_AREAS)
 349                 goto out;
 350
 351         for (i = 0; i < in->nr_areas; i++) {
 352                 for (j = 0; j < in->pages_per_area; j++)
 353                         memcpy(rc->areas[i][j], in->areas[i][j], PAGE_SIZE);
 354         }
 355 out:
 356         spin_unlock_irqrestore(&in->lock, flags);
 357         return rc;
 358 }
 359
 360 /*
 361  * debug_info_get
 362  * - increments reference count for debug-info
 363  */
 364 static void debug_info_get(debug_info_t *db_info)
 365 {
 366         if (db_info)
 367                 refcount_inc(&db_info->ref_count);
 368 }
 369
 370 /*
 371  * debug_info_put:
 372  * - decreases reference count for debug-info and frees it if necessary
 373  */
 374 static void debug_info_put(debug_info_t *db_info)
 375 {
 376         if (!db_info)
 377                 return;
 378         if (refcount_dec_and_test(&db_info->ref_count))
 379                 debug_info_free(db_info);
 380 }
 381
 382 /*
 383  * debug_format_entry:
 384  * - format one debug entry and return size of formated data
 385  */
 386 static int debug_format_entry(file_private_info_t *p_info)
 387 {
 388         debug_info_t *id_snap   = p_info->debug_info_snap;
 389         struct debug_view *view = p_info->view;
 390         debug_entry_t *act_entry;
 391         size_t len = 0;
 392
 393         if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
 394                 /* print prolog */
 395                 if (view->prolog_proc)
 396                         len += view->prolog_proc(id_snap, view, p_info->temp_buf);
 397                 goto out;
 398         }
 399         if (!id_snap->areas) /* this is true, if we have a prolog only view */
 400                 goto out;    /* or if 'pages_per_area' is 0 */
 401         act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
 402                                        [p_info->act_page] + p_info->act_entry);
 403
 404         if (act_entry->clock == 0LL)
 405                 goto out; /* empty entry */
 406         if (view->header_proc)
 407                 len += view->header_proc(id_snap, view, p_info->act_area,
 408                                          act_entry, p_info->temp_buf + len);
 409         if (view->format_proc)
 410                 len += view->format_proc(id_snap, view, p_info->temp_buf + len,
 411                                          DEBUG_DATA(act_entry));
 412 out:
 413         return len;
 414 }
 415
 416 /*
 417  * debug_next_entry:
 418  * - goto next entry in p_info
 419  */
 420 static inline int debug_next_entry(file_private_info_t *p_info)
 421 {
 422         debug_info_t *id;
 423
 424         id = p_info->debug_info_snap;
 425         if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
 426                 p_info->act_entry = 0;
 427                 p_info->act_page  = 0;
 428                 goto out;
 429         }
 430         if (!id->areas)
 431                 return 1;
 432         p_info->act_entry += id->entry_size;
 433         /* switch to next page, if we reached the end of the page  */
 434         if (p_info->act_entry > (PAGE_SIZE - id->entry_size)) {
 435                 /* next page */
 436                 p_info->act_entry = 0;
 437                 p_info->act_page += 1;
 438                 if ((p_info->act_page % id->pages_per_area) == 0) {
 439                         /* next area */
 440                         p_info->act_area++;
 441                         p_info->act_page = 0;
 442                 }
 443                 if (p_info->act_area >= id->nr_areas)
 444                         return 1;
 445         }
 446 out:
 447         return 0;
 448 }
 449
 450 /*
 451  * debug_output:
 452  * - called for user read()
 453  * - copies formated debug entries to the user buffer
 454  */
 455 static ssize_t debug_output(struct file *file,          /* file descriptor */
 456                             char __user *user_buf,      /* user buffer */
 457                             size_t len,                 /* length of buffer */
 458                             loff_t *offset)             /* offset in the file */
 459 {
 460         size_t count = 0;
 461         size_t entry_offset;
 462         file_private_info_t *p_info;
 463
 464         p_info = (file_private_info_t *) file->private_data;
 465         if (*offset != p_info->offset)
 466                 return -EPIPE;
 467         if (p_info->act_area >= p_info->debug_info_snap->nr_areas)
 468                 return 0;
 469         entry_offset = p_info->act_entry_offset;
 470         while (count < len) {
 471                 int formatted_line_residue;
 472                 int formatted_line_size;
 473                 int user_buf_residue;
 474                 size_t copy_size;
 475
 476                 formatted_line_size = debug_format_entry(p_info);
 477                 formatted_line_residue = formatted_line_size - entry_offset;
 478                 user_buf_residue = len-count;
 479                 copy_size = min(user_buf_residue, formatted_line_residue);
 480                 if (copy_size) {
 481                         if (copy_to_user(user_buf + count, p_info->temp_buf
 482                                          + entry_offset, copy_size))
 483                                 return -EFAULT;
 484                         count += copy_size;
 485                         entry_offset += copy_size;
 486                 }
 487                 if (copy_size == formatted_line_residue) {
 488                         entry_offset = 0;
 489                         if (debug_next_entry(p_info))
 490                                 goto out;
 491                 }
 492         }
 493 out:
 494         p_info->offset           = *offset + count;
 495         p_info->act_entry_offset = entry_offset;
 496         *offset = p_info->offset;
 497         return count;
 498 }
 499
 500 /*
 501  * debug_input:
 502  * - called for user write()
 503  * - calls input function of view
 504  */
 505 static ssize_t debug_input(struct file *file, const char __user *user_buf,
 506                            size_t length, loff_t *offset)
 507 {
 508         file_private_info_t *p_info;
 509         int rc = 0;
 510
 511         mutex_lock(&debug_mutex);
 512         p_info = ((file_private_info_t *) file->private_data);
 513         if (p_info->view->input_proc) {
 514                 rc = p_info->view->input_proc(p_info->debug_info_org,
 515                                               p_info->view, file, user_buf,
 516                                               length, offset);
 517         } else {
 518                 rc = -EPERM;
 519         }
 520         mutex_unlock(&debug_mutex);
 521         return rc; /* number of input characters */
 522 }
 523
 524 /*
 525  * debug_open:
 526  * - called for user open()
 527  * - copies formated output to private_data area of the file
 528  *   handle
 529  */
 530 static int debug_open(struct inode *inode, struct file *file)
 531 {
 532         debug_info_t *debug_info, *debug_info_snapshot;
 533         file_private_info_t *p_info;
 534         int i, rc = 0;
 535
 536         mutex_lock(&debug_mutex);
 537         debug_info = file_inode(file)->i_private;
 538         /* find debug view */
 539         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
 540                 if (!debug_info->views[i])
 541                         continue;
 542                 else if (debug_info->debugfs_entries[i] == file->f_path.dentry)
 543                         goto found; /* found view ! */
 544         }
 545         /* no entry found */
 546         rc = -EINVAL;
 547         goto out;
 548
 549 found:
 550
 551         /* Make snapshot of current debug areas to get it consistent.     */
 552         /* To copy all the areas is only needed, if we have a view which  */
 553         /* formats the debug areas. */
 554
 555         if (!debug_info->views[i]->format_proc && !debug_info->views[i]->header_proc)
 556                 debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
 557         else
 558                 debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
 559
 560         if (!debug_info_snapshot) {
 561                 rc = -ENOMEM;
 562                 goto out;
 563         }
 564         p_info = kmalloc(sizeof(file_private_info_t), GFP_KERNEL);
 565         if (!p_info) {
 566                 debug_info_free(debug_info_snapshot);
 567                 rc = -ENOMEM;
 568                 goto out;
 569         }
 570         p_info->offset = 0;
 571         p_info->debug_info_snap = debug_info_snapshot;
 572         p_info->debug_info_org  = debug_info;
 573         p_info->view = debug_info->views[i];
 574         p_info->act_area = 0;
 575         p_info->act_page = 0;
 576         p_info->act_entry = DEBUG_PROLOG_ENTRY;
 577         p_info->act_entry_offset = 0;
 578         file->private_data = p_info;
 579         debug_info_get(debug_info);
 580         nonseekable_open(inode, file);
 581 out:
 582         mutex_unlock(&debug_mutex);
 583         return rc;
 584 }
 585
 586 /*
 587  * debug_close:
 588  * - called for user close()
 589  * - deletes  private_data area of the file handle
 590  */
 591 static int debug_close(struct inode *inode, struct file *file)
 592 {
 593         file_private_info_t *p_info;
 594
 595         p_info = (file_private_info_t *) file->private_data;
 596         if (p_info->debug_info_snap)
 597                 debug_info_free(p_info->debug_info_snap);
 598         debug_info_put(p_info->debug_info_org);
 599         kfree(file->private_data);
 600         return 0; /* success */
 601 }
 602
 603 /* Create debugfs entries and add to internal list. */
 604 static void _debug_register(debug_info_t *id)
 605 {
 606         /* create root directory */
 607         id->debugfs_root_entry = debugfs_create_dir(id->name,
 608                                                     debug_debugfs_root_entry);
 609
 610         /* append new element to linked list */
 611         if (!debug_area_first) {
 612                 /* first element in list */
 613                 debug_area_first = id;
 614                 id->prev = NULL;
 615         } else {
 616                 /* append element to end of list */
 617                 debug_area_last->next = id;
 618                 id->prev = debug_area_last;
 619         }
 620         debug_area_last = id;
 621         id->next = NULL;
 622
 623         debug_register_view(id, &debug_level_view);
 624         debug_register_view(id, &debug_flush_view);
 625         debug_register_view(id, &debug_pages_view);
 626 }
 627
 628 /**
 629  * debug_register_mode() - creates and initializes debug area.
 630  *
 631  * @name:       Name of debug log (e.g. used for debugfs entry)
 632  * @pages_per_area:     Number of pages, which will be allocated per area
 633  * @nr_areas:   Number of debug areas
 634  * @buf_size:   Size of data area in each debug entry
 635  * @mode:       File mode for debugfs files. E.g. S_IRWXUGO
 636  * @uid:        User ID for debugfs files. Currently only 0 is supported.
 637  * @gid:        Group ID for debugfs files. Currently only 0 is supported.
 638  *
 639  * Return:
 640  * - Handle for generated debug area
 641  * - %NULL if register failed
 642  *
 643  * Allocates memory for a debug log.
 644  * Must not be called within an interrupt handler.
 645  */
 646 debug_info_t *debug_register_mode(const char *name, int pages_per_area,
 647                                   int nr_areas, int buf_size, umode_t mode,
 648                                   uid_t uid, gid_t gid)
 649 {
 650         debug_info_t *rc = NULL;
 651
 652         /* Since debugfs currently does not support uid/gid other than root, */
 653         /* we do not allow gid/uid != 0 until we get support for that. */
 654         if ((uid != 0) || (gid != 0))
 655                 pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
 656         BUG_ON(!initialized);
 657
 658         /* create new debug_info */
 659         rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
 660         if (rc) {
 661                 mutex_lock(&debug_mutex);
 662                 _debug_register(rc);
 663                 mutex_unlock(&debug_mutex);
 664         } else {
 665                 pr_err("Registering debug feature %s failed\n", name);
 666         }
 667         return rc;
 668 }
 669 EXPORT_SYMBOL(debug_register_mode);
 670
 671 /**
 672  * debug_register() - creates and initializes debug area with default file mode.
 673  *
 674  * @name:       Name of debug log (e.g. used for debugfs entry)
 675  * @pages_per_area:     Number of pages, which will be allocated per area
 676  * @nr_areas:   Number of debug areas
 677  * @buf_size:   Size of data area in each debug entry
 678  *
 679  * Return:
 680  * - Handle for generated debug area
 681  * - %NULL if register failed
 682  *
 683  * Allocates memory for a debug log.
 684  * The debugfs file mode access permissions are read and write for user.
 685  * Must not be called within an interrupt handler.
 686  */
 687 debug_info_t *debug_register(const char *name, int pages_per_area,
 688                              int nr_areas, int buf_size)
 689 {
 690         return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
 691                                    S_IRUSR | S_IWUSR, 0, 0);
 692 }
 693 EXPORT_SYMBOL(debug_register);
 694
 695 /* Remove debugfs entries and remove from internal list. */
 696 static void _debug_unregister(debug_info_t *id)
 697 {
 698         int i;
 699
 700         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
 701                 if (!id->views[i])
 702                         continue;
 703                 debugfs_remove(id->debugfs_entries[i]);
 704         }
 705         debugfs_remove(id->debugfs_root_entry);
 706         if (id == debug_area_first)
 707                 debug_area_first = id->next;
 708         if (id == debug_area_last)
 709                 debug_area_last = id->prev;
 710         if (id->prev)
 711                 id->prev->next = id->next;
 712         if (id->next)
 713                 id->next->prev = id->prev;
 714 }
 715
 716 /**
 717  * debug_unregister() - give back debug area.
 718  *
 719  * @id:         handle for debug log
 720  *
 721  * Return:
 722  *    none
 723  */
 724 void debug_unregister(debug_info_t *id)
 725 {
 726         if (!id)
 727                 return;
 728         mutex_lock(&debug_mutex);
 729         _debug_unregister(id);
 730         mutex_unlock(&debug_mutex);
 731
 732         debug_info_put(id);
 733 }
 734 EXPORT_SYMBOL(debug_unregister);
 735
 736 /*
 737  * debug_set_size:
 738  * - set area size (number of pages) and number of areas
 739  */
 740 static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
 741 {
 742         debug_info_t *new_id;
 743         unsigned long flags;
 744
 745         if (!id || (nr_areas <= 0) || (pages_per_area < 0))
 746                 return -EINVAL;
 747
 748         new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
 749                                   id->level, ALL_AREAS);
 750         if (!new_id) {
 751                 pr_info("Allocating memory for %i pages failed\n",
 752                         pages_per_area);
 753                 return -ENOMEM;
 754         }
 755
 756         spin_lock_irqsave(&id->lock, flags);
 757         debug_events_append(new_id, id);
 758         debug_areas_swap(new_id, id);
 759         debug_info_free(new_id);
 760         spin_unlock_irqrestore(&id->lock, flags);
 761         pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
 762
 763         return 0;
 764 }
 765
 766 /**
 767  * debug_set_level() - Sets new actual debug level if new_level is valid.
 768  *
 769  * @id:         handle for debug log
 770  * @new_level:  new debug level
 771  *
 772  * Return:
 773  *    none
 774  */
 775 void debug_set_level(debug_info_t *id, int new_level)
 776 {
 777         unsigned long flags;
 778
 779         if (!id)
 780                 return;
 781         spin_lock_irqsave(&id->lock, flags);
 782         if (new_level == DEBUG_OFF_LEVEL) {
 783                 id->level = DEBUG_OFF_LEVEL;
 784                 pr_info("%s: switched off\n", id->name);
 785         } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
 786                 pr_info("%s: level %i is out of range (%i - %i)\n",
 787                         id->name, new_level, 0, DEBUG_MAX_LEVEL);
 788         } else {
 789                 id->level = new_level;
 790         }
 791         spin_unlock_irqrestore(&id->lock, flags);
 792 }
 793 EXPORT_SYMBOL(debug_set_level);
 794
 795 /*
 796  * proceed_active_entry:
 797  * - set active entry to next in the ring buffer
 798  */
 799 static inline void proceed_active_entry(debug_info_t *id)
 800 {
 801         if ((id->active_entries[id->active_area] += id->entry_size)
 802             > (PAGE_SIZE - id->entry_size)) {
 803                 id->active_entries[id->active_area] = 0;
 804                 id->active_pages[id->active_area] =
 805                         (id->active_pages[id->active_area] + 1) %
 806                         id->pages_per_area;
 807         }
 808 }
 809
 810 /*
 811  * proceed_active_area:
 812  * - set active area to next in the ring buffer
 813  */
 814 static inline void proceed_active_area(debug_info_t *id)
 815 {
 816         id->active_area++;
 817         id->active_area = id->active_area % id->nr_areas;
 818 }
 819
 820 /*
 821  * get_active_entry:
 822  */
 823 static inline debug_entry_t *get_active_entry(debug_info_t *id)
 824 {
 825         return (debug_entry_t *) (((char *) id->areas[id->active_area]
 826                                    [id->active_pages[id->active_area]]) +
 827                                   id->active_entries[id->active_area]);
 828 }
 829
 830 /* Swap debug areas of a and b. */
 831 static void debug_areas_swap(debug_info_t *a, debug_info_t *b)
 832 {
 833         swap(a->nr_areas, b->nr_areas);
 834         swap(a->pages_per_area, b->pages_per_area);
 835         swap(a->areas, b->areas);
 836         swap(a->active_area, b->active_area);
 837         swap(a->active_pages, b->active_pages);
 838         swap(a->active_entries, b->active_entries);
 839 }
 840
 841 /* Append all debug events in active area from source to destination log. */
 842 static void debug_events_append(debug_info_t *dest, debug_info_t *src)
 843 {
 844         debug_entry_t *from, *to, *last;
 845
 846         if (!src->areas || !dest->areas)
 847                 return;
 848
 849         /* Loop over all entries in src, starting with oldest. */
 850         from = get_active_entry(src);
 851         last = from;
 852         do {
 853                 if (from->clock != 0LL) {
 854                         to = get_active_entry(dest);
 855                         memset(to, 0, dest->entry_size);
 856                         memcpy(to, from, min(src->entry_size,
 857                                              dest->entry_size));
 858                         proceed_active_entry(dest);
 859                 }
 860
 861                 proceed_active_entry(src);
 862                 from = get_active_entry(src);
 863         } while (from != last);
 864 }
 865
 866 /*
 867  * debug_finish_entry:
 868  * - set timestamp, caller address, cpu number etc.
 869  */
 870
 871 static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
 872                                       int level, int exception)
 873 {
 874         unsigned long timestamp;
 875         union tod_clock clk;
 876
 877         store_tod_clock_ext(&clk);
 878         timestamp = clk.us;
 879         timestamp -= TOD_UNIX_EPOCH >> 12;
 880         active->clock = timestamp;
 881         active->cpu = smp_processor_id();
 882         active->caller = __builtin_return_address(0);
 883         active->exception = exception;
 884         active->level = level;
 885         proceed_active_entry(id);
 886         if (exception)
 887                 proceed_active_area(id);
 888 }
 889
 890 static int debug_stoppable = 1;
 891 static int debug_active = 1;
 892
 893 #define CTL_S390DBF_STOPPABLE 5678
 894 #define CTL_S390DBF_ACTIVE 5679
 895
 896 /*
 897  * proc handler for the running debug_active sysctl
 898  * always allow read, allow write only if debug_stoppable is set or
 899  * if debug_active is already off
 900  */
 901 static int s390dbf_procactive(struct ctl_table *table, int write,
 902                               void *buffer, size_t *lenp, loff_t *ppos)
 903 {
 904         if (!write || debug_stoppable || !debug_active)
 905                 return proc_dointvec(table, write, buffer, lenp, ppos);
 906         else
 907                 return 0;
 908 }
 909
 910 static struct ctl_table s390dbf_table[] = {
 911         {
 912                 .procname       = "debug_stoppable",
 913                 .data           = &debug_stoppable,
 914                 .maxlen         = sizeof(int),
 915                 .mode           = S_IRUGO | S_IWUSR,
 916                 .proc_handler   = proc_dointvec,
 917         },
 918         {
 919                 .procname       = "debug_active",
 920                 .data           = &debug_active,
 921                 .maxlen         = sizeof(int),
 922                 .mode           = S_IRUGO | S_IWUSR,
 923                 .proc_handler   = s390dbf_procactive,
 924         },
 925         { }
 926 };
 927
 928 static struct ctl_table s390dbf_dir_table[] = {
 929         {
 930                 .procname       = "s390dbf",
 931                 .maxlen         = 0,
 932                 .mode           = S_IRUGO | S_IXUGO,
 933                 .child          = s390dbf_table,
 934         },
 935         { }
 936 };
 937
 938 static struct ctl_table_header *s390dbf_sysctl_header;
 939
 940 /**
 941  * debug_stop_all() - stops the debug feature if stopping is allowed.
 942  *
 943  * Return:
 944  * -   none
 945  *
 946  * Currently used in case of a kernel oops.
 947  */
 948 void debug_stop_all(void)
 949 {
 950         if (debug_stoppable)
 951                 debug_active = 0;
 952 }
 953 EXPORT_SYMBOL(debug_stop_all);
 954
 955 /**
 956  * debug_set_critical() - event/exception functions try lock instead of spin.
 957  *
 958  * Return:
 959  * -   none
 960  *
 961  * Currently used in case of stopping all CPUs but the current one.
 962  * Once in this state, functions to write a debug entry for an
 963  * event or exception no longer spin on the debug area lock,
 964  * but only try to get it and fail if they do not get the lock.
 965  */
 966 void debug_set_critical(void)
 967 {
 968         debug_critical = 1;
 969 }
 970
 971 /*
 972  * debug_event_common:
 973  * - write debug entry with given size
 974  */
 975 debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
 976                                   int len)
 977 {
 978         debug_entry_t *active;
 979         unsigned long flags;
 980
 981         if (!debug_active || !id->areas)
 982                 return NULL;
 983         if (debug_critical) {
 984                 if (!spin_trylock_irqsave(&id->lock, flags))
 985                         return NULL;
 986         } else {
 987                 spin_lock_irqsave(&id->lock, flags);
 988         }
 989         do {
 990                 active = get_active_entry(id);
 991                 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
 992                 if (len < id->buf_size)
 993                         memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
 994                 debug_finish_entry(id, active, level, 0);
 995                 len -= id->buf_size;
 996                 buf += id->buf_size;
 997         } while (len > 0);
 998
 999         spin_unlock_irqrestore(&id->lock, flags);
1000         return active;
1001 }
1002 EXPORT_SYMBOL(debug_event_common);
1003
1004 /*
1005  * debug_exception_common:
1006  * - write debug entry with given size and switch to next debug area
1007  */
1008 debug_entry_t *debug_exception_common(debug_info_t *id, int level,
1009                                       const void *buf, int len)
1010 {
1011         debug_entry_t *active;
1012         unsigned long flags;
1013
1014         if (!debug_active || !id->areas)
1015                 return NULL;
1016         if (debug_critical) {
1017                 if (!spin_trylock_irqsave(&id->lock, flags))
1018                         return NULL;
1019         } else {
1020                 spin_lock_irqsave(&id->lock, flags);
1021         }
1022         do {
1023                 active = get_active_entry(id);
1024                 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1025                 if (len < id->buf_size)
1026                         memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1027                 debug_finish_entry(id, active, level, len <= id->buf_size);
1028                 len -= id->buf_size;
1029                 buf += id->buf_size;
1030         } while (len > 0);
1031
1032         spin_unlock_irqrestore(&id->lock, flags);
1033         return active;
1034 }
1035 EXPORT_SYMBOL(debug_exception_common);
1036
1037 /*
1038  * counts arguments in format string for sprintf view
1039  */
1040 static inline int debug_count_numargs(char *string)
1041 {
1042         int numargs = 0;
1043
1044         while (*string) {
1045                 if (*string++ == '%')
1046                         numargs++;
1047         }
1048         return numargs;
1049 }
1050
1051 /*
1052  * debug_sprintf_event:
1053  */
1054 debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
1055 {
1056         debug_sprintf_entry_t *curr_event;
1057         debug_entry_t *active;
1058         unsigned long flags;
1059         int numargs, idx;
1060         va_list ap;
1061
1062         if (!debug_active || !id->areas)
1063                 return NULL;
1064         numargs = debug_count_numargs(string);
1065
1066         if (debug_critical) {
1067                 if (!spin_trylock_irqsave(&id->lock, flags))
1068                         return NULL;
1069         } else {
1070                 spin_lock_irqsave(&id->lock, flags);
1071         }
1072         active = get_active_entry(id);
1073         curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
1074         va_start(ap, string);
1075         curr_event->string = string;
1076         for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1077                 curr_event->args[idx] = va_arg(ap, long);
1078         va_end(ap);
1079         debug_finish_entry(id, active, level, 0);
1080         spin_unlock_irqrestore(&id->lock, flags);
1081
1082         return active;
1083 }
1084 EXPORT_SYMBOL(__debug_sprintf_event);
1085
1086 /*
1087  * debug_sprintf_exception:
1088  */
1089 debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1090 {
1091         debug_sprintf_entry_t *curr_event;
1092         debug_entry_t *active;
1093         unsigned long flags;
1094         int numargs, idx;
1095         va_list ap;
1096
1097         if (!debug_active || !id->areas)
1098                 return NULL;
1099
1100         numargs = debug_count_numargs(string);
1101
1102         if (debug_critical) {
1103                 if (!spin_trylock_irqsave(&id->lock, flags))
1104                         return NULL;
1105         } else {
1106                 spin_lock_irqsave(&id->lock, flags);
1107         }
1108         active = get_active_entry(id);
1109         curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
1110         va_start(ap, string);
1111         curr_event->string = string;
1112         for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1113                 curr_event->args[idx] = va_arg(ap, long);
1114         va_end(ap);
1115         debug_finish_entry(id, active, level, 1);
1116         spin_unlock_irqrestore(&id->lock, flags);
1117
1118         return active;
1119 }
1120 EXPORT_SYMBOL(__debug_sprintf_exception);
1121
1122 /**
1123  * debug_register_view() - registers new debug view and creates debugfs
1124  *                         dir entry
1125  *
1126  * @id:         handle for debug log
1127  * @view:       pointer to debug view struct
1128  *
1129  * Return:
1130  * -   0  : ok
1131  * -   < 0: Error
1132  */
1133 int debug_register_view(debug_info_t *id, struct debug_view *view)
1134 {
1135         unsigned long flags;
1136         struct dentry *pde;
1137         umode_t mode;
1138         int rc = 0;
1139         int i;
1140
1141         if (!id)
1142                 goto out;
1143         mode = (id->mode | S_IFREG) & ~S_IXUGO;
1144         if (!(view->prolog_proc || view->format_proc || view->header_proc))
1145                 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1146         if (!view->input_proc)
1147                 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1148         pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1149                                   id, &debug_file_ops);
1150         spin_lock_irqsave(&id->lock, flags);
1151         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1152                 if (!id->views[i])
1153                         break;
1154         }
1155         if (i == DEBUG_MAX_VIEWS) {
1156                 pr_err("Registering view %s/%s would exceed the maximum "
1157                        "number of views %i\n", id->name, view->name, i);
1158                 rc = -1;
1159         } else {
1160                 id->views[i] = view;
1161                 id->debugfs_entries[i] = pde;
1162         }
1163         spin_unlock_irqrestore(&id->lock, flags);
1164         if (rc)
1165                 debugfs_remove(pde);
1166 out:
1167         return rc;
1168 }
1169 EXPORT_SYMBOL(debug_register_view);
1170
1171 /**
1172  * debug_unregister_view() - unregisters debug view and removes debugfs
1173  *                           dir entry
1174  *
1175  * @id:         handle for debug log
1176  * @view:       pointer to debug view struct
1177  *
1178  * Return:
1179  * -   0  : ok
1180  * -   < 0: Error
1181  */
1182 int debug_unregister_view(debug_info_t *id, struct debug_view *view)
1183 {
1184         struct dentry *dentry = NULL;
1185         unsigned long flags;
1186         int i, rc = 0;
1187
1188         if (!id)
1189                 goto out;
1190         spin_lock_irqsave(&id->lock, flags);
1191         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1192                 if (id->views[i] == view)
1193                         break;
1194         }
1195         if (i == DEBUG_MAX_VIEWS) {
1196                 rc = -1;
1197         } else {
1198                 dentry = id->debugfs_entries[i];
1199                 id->views[i] = NULL;
1200                 id->debugfs_entries[i] = NULL;
1201         }
1202         spin_unlock_irqrestore(&id->lock, flags);
1203         debugfs_remove(dentry);
1204 out:
1205         return rc;
1206 }
1207 EXPORT_SYMBOL(debug_unregister_view);
1208
1209 static inline char *debug_get_user_string(const char __user *user_buf,
1210                                           size_t user_len)
1211 {
1212         char *buffer;
1213
1214         buffer = kmalloc(user_len + 1, GFP_KERNEL);
1215         if (!buffer)
1216                 return ERR_PTR(-ENOMEM);
1217         if (copy_from_user(buffer, user_buf, user_len) != 0) {
1218                 kfree(buffer);
1219                 return ERR_PTR(-EFAULT);
1220         }
1221         /* got the string, now strip linefeed. */
1222         if (buffer[user_len - 1] == '\n')
1223                 buffer[user_len - 1] = 0;
1224         else
1225                 buffer[user_len] = 0;
1226         return buffer;
1227 }
1228
1229 static inline int debug_get_uint(char *buf)
1230 {
1231         int rc;
1232
1233         buf = skip_spaces(buf);
1234         rc = simple_strtoul(buf, &buf, 10);
1235         if (*buf)
1236                 rc = -EINVAL;
1237         return rc;
1238 }
1239
1240 /*
1241  * functions for debug-views
1242  ***********************************
1243 */
1244
1245 /*
1246  * prints out actual debug level
1247  */
1248
1249 static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
1250                                  char *out_buf)
1251 {
1252         return sprintf(out_buf, "%i\n", id->pages_per_area);
1253 }
1254
1255 /*
1256  * reads new size (number of pages per debug area)
1257  */
1258
1259 static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
1260                                 struct file *file, const char __user *user_buf,
1261                                 size_t user_len, loff_t *offset)
1262 {
1263         int rc, new_pages;
1264         char *str;
1265
1266         if (user_len > 0x10000)
1267                 user_len = 0x10000;
1268         if (*offset != 0) {
1269                 rc = -EPIPE;
1270                 goto out;
1271         }
1272         str = debug_get_user_string(user_buf, user_len);
1273         if (IS_ERR(str)) {
1274                 rc = PTR_ERR(str);
1275                 goto out;
1276         }
1277         new_pages = debug_get_uint(str);
1278         if (new_pages < 0) {
1279                 rc = -EINVAL;
1280                 goto free_str;
1281         }
1282         rc = debug_set_size(id, id->nr_areas, new_pages);
1283         if (rc != 0) {
1284                 rc = -EINVAL;
1285                 goto free_str;
1286         }
1287         rc = user_len;
1288 free_str:
1289         kfree(str);
1290 out:
1291         *offset += user_len;
1292         return rc;              /* number of input characters */
1293 }
1294
1295 /*
1296  * prints out actual debug level
1297  */
1298 static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
1299                                  char *out_buf)
1300 {
1301         int rc = 0;
1302
1303         if (id->level == DEBUG_OFF_LEVEL)
1304                 rc = sprintf(out_buf, "-\n");
1305         else
1306                 rc = sprintf(out_buf, "%i\n", id->level);
1307         return rc;
1308 }
1309
1310 /*
1311  * reads new debug level
1312  */
1313 static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
1314                                 struct file *file, const char __user *user_buf,
1315                                 size_t user_len, loff_t *offset)
1316 {
1317         int rc, new_level;
1318         char *str;
1319
1320         if (user_len > 0x10000)
1321                 user_len = 0x10000;
1322         if (*offset != 0) {
1323                 rc = -EPIPE;
1324                 goto out;
1325         }
1326         str = debug_get_user_string(user_buf, user_len);
1327         if (IS_ERR(str)) {
1328                 rc = PTR_ERR(str);
1329                 goto out;
1330         }
1331         if (str[0] == '-') {
1332                 debug_set_level(id, DEBUG_OFF_LEVEL);
1333                 rc = user_len;
1334                 goto free_str;
1335         } else {
1336                 new_level = debug_get_uint(str);
1337         }
1338         if (new_level < 0) {
1339                 pr_warn("%s is not a valid level for a debug feature\n", str);
1340                 rc = -EINVAL;
1341         } else {
1342                 debug_set_level(id, new_level);
1343                 rc = user_len;
1344         }
1345 free_str:
1346         kfree(str);
1347 out:
1348         *offset += user_len;
1349         return rc;              /* number of input characters */
1350 }
1351
1352 /*
1353  * flushes debug areas
1354  */
1355 static void debug_flush(debug_info_t *id, int area)
1356 {
1357         unsigned long flags;
1358         int i, j;
1359
1360         if (!id || !id->areas)
1361                 return;
1362         spin_lock_irqsave(&id->lock, flags);
1363         if (area == DEBUG_FLUSH_ALL) {
1364                 id->active_area = 0;
1365                 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1366                 for (i = 0; i < id->nr_areas; i++) {
1367                         id->active_pages[i] = 0;
1368                         for (j = 0; j < id->pages_per_area; j++)
1369                                 memset(id->areas[i][j], 0, PAGE_SIZE);
1370                 }
1371         } else if (area >= 0 && area < id->nr_areas) {
1372                 id->active_entries[area] = 0;
1373                 id->active_pages[area] = 0;
1374                 for (i = 0; i < id->pages_per_area; i++)
1375                         memset(id->areas[area][i], 0, PAGE_SIZE);
1376         }
1377         spin_unlock_irqrestore(&id->lock, flags);
1378 }
1379
1380 /*
1381  * view function: flushes debug areas
1382  */
1383 static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
1384                                 struct file *file, const char __user *user_buf,
1385                                 size_t user_len, loff_t *offset)
1386 {
1387         char input_buf[1];
1388         int rc = user_len;
1389
1390         if (user_len > 0x10000)
1391                 user_len = 0x10000;
1392         if (*offset != 0) {
1393                 rc = -EPIPE;
1394                 goto out;
1395         }
1396         if (copy_from_user(input_buf, user_buf, 1)) {
1397                 rc = -EFAULT;
1398                 goto out;
1399         }
1400         if (input_buf[0] == '-') {
1401                 debug_flush(id, DEBUG_FLUSH_ALL);
1402                 goto out;
1403         }
1404         if (isdigit(input_buf[0])) {
1405                 int area = ((int) input_buf[0] - (int) '0');
1406
1407                 debug_flush(id, area);
1408                 goto out;
1409         }
1410
1411         pr_info("Flushing debug data failed because %c is not a valid "
1412                  "area\n", input_buf[0]);
1413
1414 out:
1415         *offset += user_len;
1416         return rc;              /* number of input characters */
1417 }
1418
1419 /*
1420  * prints debug data in hex/ascii format
1421  */
1422 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
1423                                      char *out_buf, const char *in_buf)
1424 {
1425         int i, rc = 0;
1426
1427         for (i = 0; i < id->buf_size; i++)
1428                 rc += sprintf(out_buf + rc, "%02x ", ((unsigned char *) in_buf)[i]);
1429         rc += sprintf(out_buf + rc, "| ");
1430         for (i = 0; i < id->buf_size; i++) {
1431                 unsigned char c = in_buf[i];
1432
1433                 if (isascii(c) && isprint(c))
1434                         rc += sprintf(out_buf + rc, "%c", c);
1435                 else
1436                         rc += sprintf(out_buf + rc, ".");
1437         }
1438         rc += sprintf(out_buf + rc, "\n");
1439         return rc;
1440 }
1441
1442 /*
1443  * prints header for debug entry
1444  */
1445 int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
1446                          int area, debug_entry_t *entry, char *out_buf)
1447 {
1448         unsigned long sec, usec;
1449         unsigned long caller;
1450         unsigned int level;
1451         char *except_str;
1452         int rc = 0;
1453
1454         level = entry->level;
1455         sec = entry->clock;
1456         usec = do_div(sec, USEC_PER_SEC);
1457
1458         if (entry->exception)
1459                 except_str = "*";
1460         else
1461                 except_str = "-";
1462         caller = (unsigned long) entry->caller;
1463         rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %04u %px  ",
1464                       area, sec, usec, level, except_str,
1465                       entry->cpu, (void *)caller);
1466         return rc;
1467 }
1468 EXPORT_SYMBOL(debug_dflt_header_fn);
1469
1470 /*
1471  * prints debug data sprintf-formated:
1472  * debug_sprinf_event/exception calls must be used together with this view
1473  */
1474
1475 #define DEBUG_SPRINTF_MAX_ARGS 10
1476
1477 static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
1478                                    char *out_buf, debug_sprintf_entry_t *curr_event)
1479 {
1480         int num_longs, num_used_args = 0, i, rc = 0;
1481         int index[DEBUG_SPRINTF_MAX_ARGS];
1482
1483         /* count of longs fit into one entry */
1484         num_longs = id->buf_size / sizeof(long);
1485
1486         if (num_longs < 1)
1487                 goto out; /* bufsize of entry too small */
1488         if (num_longs == 1) {
1489                 /* no args, we use only the string */
1490                 strcpy(out_buf, curr_event->string);
1491                 rc = strlen(curr_event->string);
1492                 goto out;
1493         }
1494
1495         /* number of arguments used for sprintf (without the format string) */
1496         num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1497
1498         memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1499
1500         for (i = 0; i < num_used_args; i++)
1501                 index[i] = i;
1502
1503         rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1504                      curr_event->args[index[1]], curr_event->args[index[2]],
1505                      curr_event->args[index[3]], curr_event->args[index[4]],
1506                      curr_event->args[index[5]], curr_event->args[index[6]],
1507                      curr_event->args[index[7]], curr_event->args[index[8]],
1508                      curr_event->args[index[9]]);
1509 out:
1510         return rc;
1511 }
1512
1513 /*
1514  * debug_init:
1515  * - is called exactly once to initialize the debug feature
1516  */
1517 static int __init debug_init(void)
1518 {
1519         s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
1520         mutex_lock(&debug_mutex);
1521         debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1522         initialized = 1;
1523         mutex_unlock(&debug_mutex);
1524         return 0;
1525 }
1526 postcore_initcall(debug_init);