arch/s390/kernel/debug.c

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This source file includes following definitions.
debug_areas_alloc
debug_info_alloc
debug_areas_free
debug_info_free
debug_info_create
debug_info_copy
debug_info_get
debug_info_put
debug_format_entry
debug_next_entry
debug_output
debug_input
debug_open
debug_close
debug_register_mode
debug_register
debug_unregister
debug_set_size
debug_set_level
proceed_active_entry
proceed_active_area
get_active_entry
debug_finish_entry
s390dbf_procactive
debug_stop_all
debug_set_critical
debug_event_common
debug_exception_common
debug_count_numargs
__debug_sprintf_event
__debug_sprintf_exception
debug_register_view
debug_unregister_view
debug_get_user_string
debug_get_uint
debug_prolog_pages_fn
debug_input_pages_fn
debug_prolog_level_fn
debug_input_level_fn
debug_flush
debug_input_flush_fn
debug_raw_header_fn
debug_raw_format_fn
debug_hex_ascii_format_fn
debug_dflt_header_fn
debug_sprintf_format_fn
debug_init
   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                 areas[i] = kmalloc_array(pages_per_area,
 202                                          sizeof(debug_entry_t *),
 203                                          GFP_KERNEL);
 204                 if (!areas[i])
 205                         goto fail_malloc_areas2;
 206                 for (j = 0; j < pages_per_area; j++) {
 207                         areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
 208                         if (!areas[i][j]) {
 209                                 for (j--; j >= 0 ; j--)
 210                                         kfree(areas[i][j]);
 211                                 kfree(areas[i]);
 212                                 goto fail_malloc_areas2;
 213                         }
 214                 }
 215         }
 216         return areas;
 217 
 218 fail_malloc_areas2:
 219         for (i--; i >= 0; i--) {
 220                 for (j = 0; j < pages_per_area; j++)
 221                         kfree(areas[i][j]);
 222                 kfree(areas[i]);
 223         }
 224         kfree(areas);
 225 fail_malloc_areas:
 226         return NULL;
 227 }
 228 
 229 /*
 230  * debug_info_alloc
 231  * - alloc new debug-info
 232  */
 233 static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,
 234                                       int nr_areas, int buf_size, int level,
 235                                       int mode)
 236 {
 237         debug_info_t *rc;
 238 
 239         /* alloc everything */
 240         rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
 241         if (!rc)
 242                 goto fail_malloc_rc;
 243         rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
 244         if (!rc->active_entries)
 245                 goto fail_malloc_active_entries;
 246         rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
 247         if (!rc->active_pages)
 248                 goto fail_malloc_active_pages;
 249         if ((mode == ALL_AREAS) && (pages_per_area != 0)) {
 250                 rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
 251                 if (!rc->areas)
 252                         goto fail_malloc_areas;
 253         } else {
 254                 rc->areas = NULL;
 255         }
 256 
 257         /* initialize members */
 258         spin_lock_init(&rc->lock);
 259         rc->pages_per_area = pages_per_area;
 260         rc->nr_areas       = nr_areas;
 261         rc->active_area    = 0;
 262         rc->level          = level;
 263         rc->buf_size       = buf_size;
 264         rc->entry_size     = sizeof(debug_entry_t) + buf_size;
 265         strlcpy(rc->name, name, sizeof(rc->name));
 266         memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
 267         memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
 268         refcount_set(&(rc->ref_count), 0);
 269 
 270         return rc;
 271 
 272 fail_malloc_areas:
 273         kfree(rc->active_pages);
 274 fail_malloc_active_pages:
 275         kfree(rc->active_entries);
 276 fail_malloc_active_entries:
 277         kfree(rc);
 278 fail_malloc_rc:
 279         return NULL;
 280 }
 281 
 282 /*
 283  * debug_areas_free
 284  * - free all debug areas
 285  */
 286 static void debug_areas_free(debug_info_t *db_info)
 287 {
 288         int i, j;
 289 
 290         if (!db_info->areas)
 291                 return;
 292         for (i = 0; i < db_info->nr_areas; i++) {
 293                 for (j = 0; j < db_info->pages_per_area; j++)
 294                         kfree(db_info->areas[i][j]);
 295                 kfree(db_info->areas[i]);
 296         }
 297         kfree(db_info->areas);
 298         db_info->areas = NULL;
 299 }
 300 
 301 /*
 302  * debug_info_free
 303  * - free memory debug-info
 304  */
 305 static void debug_info_free(debug_info_t *db_info)
 306 {
 307         debug_areas_free(db_info);
 308         kfree(db_info->active_entries);
 309         kfree(db_info->active_pages);
 310         kfree(db_info);
 311 }
 312 
 313 /*
 314  * debug_info_create
 315  * - create new debug-info
 316  */
 317 
 318 static debug_info_t *debug_info_create(const char *name, int pages_per_area,
 319                                        int nr_areas, int buf_size, umode_t mode)
 320 {
 321         debug_info_t *rc;
 322 
 323         rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
 324                               DEBUG_DEFAULT_LEVEL, ALL_AREAS);
 325         if (!rc)
 326                 goto out;
 327 
 328         rc->mode = mode & ~S_IFMT;
 329 
 330         /* create root directory */
 331         rc->debugfs_root_entry = debugfs_create_dir(rc->name,
 332                                                     debug_debugfs_root_entry);
 333 
 334         /* append new element to linked list */
 335         if (!debug_area_first) {
 336                 /* first element in list */
 337                 debug_area_first = rc;
 338                 rc->prev = NULL;
 339         } else {
 340                 /* append element to end of list */
 341                 debug_area_last->next = rc;
 342                 rc->prev = debug_area_last;
 343         }
 344         debug_area_last = rc;
 345         rc->next = NULL;
 346 
 347         refcount_set(&rc->ref_count, 1);
 348 out:
 349         return rc;
 350 }
 351 
 352 /*
 353  * debug_info_copy
 354  * - copy debug-info
 355  */
 356 static debug_info_t *debug_info_copy(debug_info_t *in, int mode)
 357 {
 358         unsigned long flags;
 359         debug_info_t *rc;
 360         int i, j;
 361 
 362         /* get a consistent copy of the debug areas */
 363         do {
 364                 rc = debug_info_alloc(in->name, in->pages_per_area,
 365                         in->nr_areas, in->buf_size, in->level, mode);
 366                 spin_lock_irqsave(&in->lock, flags);
 367                 if (!rc)
 368                         goto out;
 369                 /* has something changed in the meantime ? */
 370                 if ((rc->pages_per_area == in->pages_per_area) &&
 371                     (rc->nr_areas == in->nr_areas)) {
 372                         break;
 373                 }
 374                 spin_unlock_irqrestore(&in->lock, flags);
 375                 debug_info_free(rc);
 376         } while (1);
 377 
 378         if (mode == NO_AREAS)
 379                 goto out;
 380 
 381         for (i = 0; i < in->nr_areas; i++) {
 382                 for (j = 0; j < in->pages_per_area; j++)
 383                         memcpy(rc->areas[i][j], in->areas[i][j], PAGE_SIZE);
 384         }
 385 out:
 386         spin_unlock_irqrestore(&in->lock, flags);
 387         return rc;
 388 }
 389 
 390 /*
 391  * debug_info_get
 392  * - increments reference count for debug-info
 393  */
 394 static void debug_info_get(debug_info_t *db_info)
 395 {
 396         if (db_info)
 397                 refcount_inc(&db_info->ref_count);
 398 }
 399 
 400 /*
 401  * debug_info_put:
 402  * - decreases reference count for debug-info and frees it if necessary
 403  */
 404 static void debug_info_put(debug_info_t *db_info)
 405 {
 406         int i;
 407 
 408         if (!db_info)
 409                 return;
 410         if (refcount_dec_and_test(&db_info->ref_count)) {
 411                 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
 412                         if (!db_info->views[i])
 413                                 continue;
 414                         debugfs_remove(db_info->debugfs_entries[i]);
 415                 }
 416                 debugfs_remove(db_info->debugfs_root_entry);
 417                 if (db_info == debug_area_first)
 418                         debug_area_first = db_info->next;
 419                 if (db_info == debug_area_last)
 420                         debug_area_last = db_info->prev;
 421                 if (db_info->prev)
 422                         db_info->prev->next = db_info->next;
 423                 if (db_info->next)
 424                         db_info->next->prev = db_info->prev;
 425                 debug_info_free(db_info);
 426         }
 427 }
 428 
 429 /*
 430  * debug_format_entry:
 431  * - format one debug entry and return size of formated data
 432  */
 433 static int debug_format_entry(file_private_info_t *p_info)
 434 {
 435         debug_info_t *id_snap   = p_info->debug_info_snap;
 436         struct debug_view *view = p_info->view;
 437         debug_entry_t *act_entry;
 438         size_t len = 0;
 439 
 440         if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
 441                 /* print prolog */
 442                 if (view->prolog_proc)
 443                         len += view->prolog_proc(id_snap, view, p_info->temp_buf);
 444                 goto out;
 445         }
 446         if (!id_snap->areas) /* this is true, if we have a prolog only view */
 447                 goto out;    /* or if 'pages_per_area' is 0 */
 448         act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
 449                                        [p_info->act_page] + p_info->act_entry);
 450 
 451         if (act_entry->id.stck == 0LL)
 452                 goto out; /* empty entry */
 453         if (view->header_proc)
 454                 len += view->header_proc(id_snap, view, p_info->act_area,
 455                                          act_entry, p_info->temp_buf + len);
 456         if (view->format_proc)
 457                 len += view->format_proc(id_snap, view, p_info->temp_buf + len,
 458                                          DEBUG_DATA(act_entry));
 459 out:
 460         return len;
 461 }
 462 
 463 /*
 464  * debug_next_entry:
 465  * - goto next entry in p_info
 466  */
 467 static inline int debug_next_entry(file_private_info_t *p_info)
 468 {
 469         debug_info_t *id;
 470 
 471         id = p_info->debug_info_snap;
 472         if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
 473                 p_info->act_entry = 0;
 474                 p_info->act_page  = 0;
 475                 goto out;
 476         }
 477         if (!id->areas)
 478                 return 1;
 479         p_info->act_entry += id->entry_size;
 480         /* switch to next page, if we reached the end of the page  */
 481         if (p_info->act_entry > (PAGE_SIZE - id->entry_size)) {
 482                 /* next page */
 483                 p_info->act_entry = 0;
 484                 p_info->act_page += 1;
 485                 if ((p_info->act_page % id->pages_per_area) == 0) {
 486                         /* next area */
 487                         p_info->act_area++;
 488                         p_info->act_page = 0;
 489                 }
 490                 if (p_info->act_area >= id->nr_areas)
 491                         return 1;
 492         }
 493 out:
 494         return 0;
 495 }
 496 
 497 /*
 498  * debug_output:
 499  * - called for user read()
 500  * - copies formated debug entries to the user buffer
 501  */
 502 static ssize_t debug_output(struct file *file,          /* file descriptor */
 503                             char __user *user_buf,      /* user buffer */
 504                             size_t len,                 /* length of buffer */
 505                             loff_t *offset)             /* offset in the file */
 506 {
 507         size_t count = 0;
 508         size_t entry_offset;
 509         file_private_info_t *p_info;
 510 
 511         p_info = (file_private_info_t *) file->private_data;
 512         if (*offset != p_info->offset)
 513                 return -EPIPE;
 514         if (p_info->act_area >= p_info->debug_info_snap->nr_areas)
 515                 return 0;
 516         entry_offset = p_info->act_entry_offset;
 517         while (count < len) {
 518                 int formatted_line_residue;
 519                 int formatted_line_size;
 520                 int user_buf_residue;
 521                 size_t copy_size;
 522 
 523                 formatted_line_size = debug_format_entry(p_info);
 524                 formatted_line_residue = formatted_line_size - entry_offset;
 525                 user_buf_residue = len-count;
 526                 copy_size = min(user_buf_residue, formatted_line_residue);
 527                 if (copy_size) {
 528                         if (copy_to_user(user_buf + count, p_info->temp_buf
 529                                          + entry_offset, copy_size))
 530                                 return -EFAULT;
 531                         count += copy_size;
 532                         entry_offset += copy_size;
 533                 }
 534                 if (copy_size == formatted_line_residue) {
 535                         entry_offset = 0;
 536                         if (debug_next_entry(p_info))
 537                                 goto out;
 538                 }
 539         }
 540 out:
 541         p_info->offset           = *offset + count;
 542         p_info->act_entry_offset = entry_offset;
 543         *offset = p_info->offset;
 544         return count;
 545 }
 546 
 547 /*
 548  * debug_input:
 549  * - called for user write()
 550  * - calls input function of view
 551  */
 552 static ssize_t debug_input(struct file *file, const char __user *user_buf,
 553                            size_t length, loff_t *offset)
 554 {
 555         file_private_info_t *p_info;
 556         int rc = 0;
 557 
 558         mutex_lock(&debug_mutex);
 559         p_info = ((file_private_info_t *) file->private_data);
 560         if (p_info->view->input_proc) {
 561                 rc = p_info->view->input_proc(p_info->debug_info_org,
 562                                               p_info->view, file, user_buf,
 563                                               length, offset);
 564         } else {
 565                 rc = -EPERM;
 566         }
 567         mutex_unlock(&debug_mutex);
 568         return rc; /* number of input characters */
 569 }
 570 
 571 /*
 572  * debug_open:
 573  * - called for user open()
 574  * - copies formated output to private_data area of the file
 575  *   handle
 576  */
 577 static int debug_open(struct inode *inode, struct file *file)
 578 {
 579         debug_info_t *debug_info, *debug_info_snapshot;
 580         file_private_info_t *p_info;
 581         int i, rc = 0;
 582 
 583         mutex_lock(&debug_mutex);
 584         debug_info = file_inode(file)->i_private;
 585         /* find debug view */
 586         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
 587                 if (!debug_info->views[i])
 588                         continue;
 589                 else if (debug_info->debugfs_entries[i] == file->f_path.dentry)
 590                         goto found; /* found view ! */
 591         }
 592         /* no entry found */
 593         rc = -EINVAL;
 594         goto out;
 595 
 596 found:
 597 
 598         /* Make snapshot of current debug areas to get it consistent.     */
 599         /* To copy all the areas is only needed, if we have a view which  */
 600         /* formats the debug areas. */
 601 
 602         if (!debug_info->views[i]->format_proc && !debug_info->views[i]->header_proc)
 603                 debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
 604         else
 605                 debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
 606 
 607         if (!debug_info_snapshot) {
 608                 rc = -ENOMEM;
 609                 goto out;
 610         }
 611         p_info = kmalloc(sizeof(file_private_info_t), GFP_KERNEL);
 612         if (!p_info) {
 613                 debug_info_free(debug_info_snapshot);
 614                 rc = -ENOMEM;
 615                 goto out;
 616         }
 617         p_info->offset = 0;
 618         p_info->debug_info_snap = debug_info_snapshot;
 619         p_info->debug_info_org  = debug_info;
 620         p_info->view = debug_info->views[i];
 621         p_info->act_area = 0;
 622         p_info->act_page = 0;
 623         p_info->act_entry = DEBUG_PROLOG_ENTRY;
 624         p_info->act_entry_offset = 0;
 625         file->private_data = p_info;
 626         debug_info_get(debug_info);
 627         nonseekable_open(inode, file);
 628 out:
 629         mutex_unlock(&debug_mutex);
 630         return rc;
 631 }
 632 
 633 /*
 634  * debug_close:
 635  * - called for user close()
 636  * - deletes  private_data area of the file handle
 637  */
 638 static int debug_close(struct inode *inode, struct file *file)
 639 {
 640         file_private_info_t *p_info;
 641 
 642         p_info = (file_private_info_t *) file->private_data;
 643         if (p_info->debug_info_snap)
 644                 debug_info_free(p_info->debug_info_snap);
 645         debug_info_put(p_info->debug_info_org);
 646         kfree(file->private_data);
 647         return 0; /* success */
 648 }
 649 
 650 /**
 651  * debug_register_mode() - creates and initializes debug area.
 652  *
 653  * @name:       Name of debug log (e.g. used for debugfs entry)
 654  * @pages_per_area:     Number of pages, which will be allocated per area
 655  * @nr_areas:   Number of debug areas
 656  * @buf_size:   Size of data area in each debug entry
 657  * @mode:       File mode for debugfs files. E.g. S_IRWXUGO
 658  * @uid:        User ID for debugfs files. Currently only 0 is supported.
 659  * @gid:        Group ID for debugfs files. Currently only 0 is supported.
 660  *
 661  * Return:
 662  * - Handle for generated debug area
 663  * - %NULL if register failed
 664  *
 665  * Allocates memory for a debug log.
 666  * Must not be called within an interrupt handler.
 667  */
 668 debug_info_t *debug_register_mode(const char *name, int pages_per_area,
 669                                   int nr_areas, int buf_size, umode_t mode,
 670                                   uid_t uid, gid_t gid)
 671 {
 672         debug_info_t *rc = NULL;
 673 
 674         /* Since debugfs currently does not support uid/gid other than root, */
 675         /* we do not allow gid/uid != 0 until we get support for that. */
 676         if ((uid != 0) || (gid != 0))
 677                 pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
 678         BUG_ON(!initialized);
 679         mutex_lock(&debug_mutex);
 680 
 681         /* create new debug_info */
 682         rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
 683         if (!rc)
 684                 goto out;
 685         debug_register_view(rc, &debug_level_view);
 686         debug_register_view(rc, &debug_flush_view);
 687         debug_register_view(rc, &debug_pages_view);
 688 out:
 689         if (!rc)
 690                 pr_err("Registering debug feature %s failed\n", name);
 691         mutex_unlock(&debug_mutex);
 692         return rc;
 693 }
 694 EXPORT_SYMBOL(debug_register_mode);
 695 
 696 /**
 697  * debug_register() - creates and initializes debug area with default file mode.
 698  *
 699  * @name:       Name of debug log (e.g. used for debugfs entry)
 700  * @pages_per_area:     Number of pages, which will be allocated per area
 701  * @nr_areas:   Number of debug areas
 702  * @buf_size:   Size of data area in each debug entry
 703  *
 704  * Return:
 705  * - Handle for generated debug area
 706  * - %NULL if register failed
 707  *
 708  * Allocates memory for a debug log.
 709  * The debugfs file mode access permissions are read and write for user.
 710  * Must not be called within an interrupt handler.
 711  */
 712 debug_info_t *debug_register(const char *name, int pages_per_area,
 713                              int nr_areas, int buf_size)
 714 {
 715         return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
 716                                    S_IRUSR | S_IWUSR, 0, 0);
 717 }
 718 EXPORT_SYMBOL(debug_register);
 719 
 720 /**
 721  * debug_unregister() - give back debug area.
 722  *
 723  * @id:         handle for debug log
 724  *
 725  * Return:
 726  *    none
 727  */
 728 void debug_unregister(debug_info_t *id)
 729 {
 730         if (!id)
 731                 return;
 732         mutex_lock(&debug_mutex);
 733         debug_info_put(id);
 734         mutex_unlock(&debug_mutex);
 735 }
 736 EXPORT_SYMBOL(debug_unregister);
 737 
 738 /*
 739  * debug_set_size:
 740  * - set area size (number of pages) and number of areas
 741  */
 742 static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
 743 {
 744         debug_entry_t ***new_areas;
 745         unsigned long flags;
 746         int rc = 0;
 747 
 748         if (!id || (nr_areas <= 0) || (pages_per_area < 0))
 749                 return -EINVAL;
 750         if (pages_per_area > 0) {
 751                 new_areas = debug_areas_alloc(pages_per_area, nr_areas);
 752                 if (!new_areas) {
 753                         pr_info("Allocating memory for %i pages failed\n",
 754                                 pages_per_area);
 755                         rc = -ENOMEM;
 756                         goto out;
 757                 }
 758         } else {
 759                 new_areas = NULL;
 760         }
 761         spin_lock_irqsave(&id->lock, flags);
 762         debug_areas_free(id);
 763         id->areas = new_areas;
 764         id->nr_areas = nr_areas;
 765         id->pages_per_area = pages_per_area;
 766         id->active_area = 0;
 767         memset(id->active_entries, 0, sizeof(int)*id->nr_areas);
 768         memset(id->active_pages, 0, sizeof(int)*id->nr_areas);
 769         spin_unlock_irqrestore(&id->lock, flags);
 770         pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
 771 out:
 772         return rc;
 773 }
 774 
 775 /**
 776  * debug_set_level() - Sets new actual debug level if new_level is valid.
 777  *
 778  * @id:         handle for debug log
 779  * @new_level:  new debug level
 780  *
 781  * Return:
 782  *    none
 783  */
 784 void debug_set_level(debug_info_t *id, int new_level)
 785 {
 786         unsigned long flags;
 787 
 788         if (!id)
 789                 return;
 790         spin_lock_irqsave(&id->lock, flags);
 791         if (new_level == DEBUG_OFF_LEVEL) {
 792                 id->level = DEBUG_OFF_LEVEL;
 793                 pr_info("%s: switched off\n", id->name);
 794         } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
 795                 pr_info("%s: level %i is out of range (%i - %i)\n",
 796                         id->name, new_level, 0, DEBUG_MAX_LEVEL);
 797         } else {
 798                 id->level = new_level;
 799         }
 800         spin_unlock_irqrestore(&id->lock, flags);
 801 }
 802 EXPORT_SYMBOL(debug_set_level);
 803 
 804 /*
 805  * proceed_active_entry:
 806  * - set active entry to next in the ring buffer
 807  */
 808 static inline void proceed_active_entry(debug_info_t *id)
 809 {
 810         if ((id->active_entries[id->active_area] += id->entry_size)
 811             > (PAGE_SIZE - id->entry_size)) {
 812                 id->active_entries[id->active_area] = 0;
 813                 id->active_pages[id->active_area] =
 814                         (id->active_pages[id->active_area] + 1) %
 815                         id->pages_per_area;
 816         }
 817 }
 818 
 819 /*
 820  * proceed_active_area:
 821  * - set active area to next in the ring buffer
 822  */
 823 static inline void proceed_active_area(debug_info_t *id)
 824 {
 825         id->active_area++;
 826         id->active_area = id->active_area % id->nr_areas;
 827 }
 828 
 829 /*
 830  * get_active_entry:
 831  */
 832 static inline debug_entry_t *get_active_entry(debug_info_t *id)
 833 {
 834         return (debug_entry_t *) (((char *) id->areas[id->active_area]
 835                                    [id->active_pages[id->active_area]]) +
 836                                   id->active_entries[id->active_area]);
 837 }
 838 
 839 /*
 840  * debug_finish_entry:
 841  * - set timestamp, caller address, cpu number etc.
 842  */
 843 
 844 static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
 845                                       int level, int exception)
 846 {
 847         active->id.stck = get_tod_clock_fast() -
 848                 *(unsigned long long *) &tod_clock_base[1];
 849         active->id.fields.cpuid = smp_processor_id();
 850         active->caller = __builtin_return_address(0);
 851         active->id.fields.exception = exception;
 852         active->id.fields.level = level;
 853         proceed_active_entry(id);
 854         if (exception)
 855                 proceed_active_area(id);
 856 }
 857 
 858 static int debug_stoppable = 1;
 859 static int debug_active = 1;
 860 
 861 #define CTL_S390DBF_STOPPABLE 5678
 862 #define CTL_S390DBF_ACTIVE 5679
 863 
 864 /*
 865  * proc handler for the running debug_active sysctl
 866  * always allow read, allow write only if debug_stoppable is set or
 867  * if debug_active is already off
 868  */
 869 static int s390dbf_procactive(struct ctl_table *table, int write,
 870                               void __user *buffer, size_t *lenp, loff_t *ppos)
 871 {
 872         if (!write || debug_stoppable || !debug_active)
 873                 return proc_dointvec(table, write, buffer, lenp, ppos);
 874         else
 875                 return 0;
 876 }
 877 
 878 static struct ctl_table s390dbf_table[] = {
 879         {
 880                 .procname       = "debug_stoppable",
 881                 .data           = &debug_stoppable,
 882                 .maxlen         = sizeof(int),
 883                 .mode           = S_IRUGO | S_IWUSR,
 884                 .proc_handler   = proc_dointvec,
 885         },
 886         {
 887                 .procname       = "debug_active",
 888                 .data           = &debug_active,
 889                 .maxlen         = sizeof(int),
 890                 .mode           = S_IRUGO | S_IWUSR,
 891                 .proc_handler   = s390dbf_procactive,
 892         },
 893         { }
 894 };
 895 
 896 static struct ctl_table s390dbf_dir_table[] = {
 897         {
 898                 .procname       = "s390dbf",
 899                 .maxlen         = 0,
 900                 .mode           = S_IRUGO | S_IXUGO,
 901                 .child          = s390dbf_table,
 902         },
 903         { }
 904 };
 905 
 906 static struct ctl_table_header *s390dbf_sysctl_header;
 907 
 908 /**
 909  * debug_stop_all() - stops the debug feature if stopping is allowed.
 910  *
 911  * Return:
 912  * -   none
 913  *
 914  * Currently used in case of a kernel oops.
 915  */
 916 void debug_stop_all(void)
 917 {
 918         if (debug_stoppable)
 919                 debug_active = 0;
 920 }
 921 EXPORT_SYMBOL(debug_stop_all);
 922 
 923 /**
 924  * debug_set_critical() - event/exception functions try lock instead of spin.
 925  *
 926  * Return:
 927  * -   none
 928  *
 929  * Currently used in case of stopping all CPUs but the current one.
 930  * Once in this state, functions to write a debug entry for an
 931  * event or exception no longer spin on the debug area lock,
 932  * but only try to get it and fail if they do not get the lock.
 933  */
 934 void debug_set_critical(void)
 935 {
 936         debug_critical = 1;
 937 }
 938 
 939 /*
 940  * debug_event_common:
 941  * - write debug entry with given size
 942  */
 943 debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
 944                                   int len)
 945 {
 946         debug_entry_t *active;
 947         unsigned long flags;
 948 
 949         if (!debug_active || !id->areas)
 950                 return NULL;
 951         if (debug_critical) {
 952                 if (!spin_trylock_irqsave(&id->lock, flags))
 953                         return NULL;
 954         } else {
 955                 spin_lock_irqsave(&id->lock, flags);
 956         }
 957         do {
 958                 active = get_active_entry(id);
 959                 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
 960                 if (len < id->buf_size)
 961                         memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
 962                 debug_finish_entry(id, active, level, 0);
 963                 len -= id->buf_size;
 964                 buf += id->buf_size;
 965         } while (len > 0);
 966 
 967         spin_unlock_irqrestore(&id->lock, flags);
 968         return active;
 969 }
 970 EXPORT_SYMBOL(debug_event_common);
 971 
 972 /*
 973  * debug_exception_common:
 974  * - write debug entry with given size and switch to next debug area
 975  */
 976 debug_entry_t *debug_exception_common(debug_info_t *id, int level,
 977                                       const void *buf, int len)
 978 {
 979         debug_entry_t *active;
 980         unsigned long flags;
 981 
 982         if (!debug_active || !id->areas)
 983                 return NULL;
 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         do {
 991                 active = get_active_entry(id);
 992                 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
 993                 if (len < id->buf_size)
 994                         memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
 995                 debug_finish_entry(id, active, level, len <= id->buf_size);
 996                 len -= id->buf_size;
 997                 buf += id->buf_size;
 998         } while (len > 0);
 999 
1000         spin_unlock_irqrestore(&id->lock, flags);
1001         return active;
1002 }
1003 EXPORT_SYMBOL(debug_exception_common);
1004 
1005 /*
1006  * counts arguments in format string for sprintf view
1007  */
1008 static inline int debug_count_numargs(char *string)
1009 {
1010         int numargs = 0;
1011 
1012         while (*string) {
1013                 if (*string++ == '%')
1014                         numargs++;
1015         }
1016         return numargs;
1017 }
1018 
1019 /*
1020  * debug_sprintf_event:
1021  */
1022 debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
1023 {
1024         debug_sprintf_entry_t *curr_event;
1025         debug_entry_t *active;
1026         unsigned long flags;
1027         int numargs, idx;
1028         va_list ap;
1029 
1030         if (!debug_active || !id->areas)
1031                 return NULL;
1032         numargs = debug_count_numargs(string);
1033 
1034         if (debug_critical) {
1035                 if (!spin_trylock_irqsave(&id->lock, flags))
1036                         return NULL;
1037         } else {
1038                 spin_lock_irqsave(&id->lock, flags);
1039         }
1040         active = get_active_entry(id);
1041         curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
1042         va_start(ap, string);
1043         curr_event->string = string;
1044         for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1045                 curr_event->args[idx] = va_arg(ap, long);
1046         va_end(ap);
1047         debug_finish_entry(id, active, level, 0);
1048         spin_unlock_irqrestore(&id->lock, flags);
1049 
1050         return active;
1051 }
1052 EXPORT_SYMBOL(__debug_sprintf_event);
1053 
1054 /*
1055  * debug_sprintf_exception:
1056  */
1057 debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1058 {
1059         debug_sprintf_entry_t *curr_event;
1060         debug_entry_t *active;
1061         unsigned long flags;
1062         int numargs, idx;
1063         va_list ap;
1064 
1065         if (!debug_active || !id->areas)
1066                 return NULL;
1067 
1068         numargs = debug_count_numargs(string);
1069 
1070         if (debug_critical) {
1071                 if (!spin_trylock_irqsave(&id->lock, flags))
1072                         return NULL;
1073         } else {
1074                 spin_lock_irqsave(&id->lock, flags);
1075         }
1076         active = get_active_entry(id);
1077         curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
1078         va_start(ap, string);
1079         curr_event->string = string;
1080         for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1081                 curr_event->args[idx] = va_arg(ap, long);
1082         va_end(ap);
1083         debug_finish_entry(id, active, level, 1);
1084         spin_unlock_irqrestore(&id->lock, flags);
1085 
1086         return active;
1087 }
1088 EXPORT_SYMBOL(__debug_sprintf_exception);
1089 
1090 /**
1091  * debug_register_view() - registers new debug view and creates debugfs
1092  *                         dir entry
1093  *
1094  * @id:         handle for debug log
1095  * @view:       pointer to debug view struct
1096  *
1097  * Return:
1098  * -   0  : ok
1099  * -   < 0: Error
1100  */
1101 int debug_register_view(debug_info_t *id, struct debug_view *view)
1102 {
1103         unsigned long flags;
1104         struct dentry *pde;
1105         umode_t mode;
1106         int rc = 0;
1107         int i;
1108 
1109         if (!id)
1110                 goto out;
1111         mode = (id->mode | S_IFREG) & ~S_IXUGO;
1112         if (!(view->prolog_proc || view->format_proc || view->header_proc))
1113                 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1114         if (!view->input_proc)
1115                 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1116         pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1117                                   id, &debug_file_ops);
1118         spin_lock_irqsave(&id->lock, flags);
1119         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1120                 if (!id->views[i])
1121                         break;
1122         }
1123         if (i == DEBUG_MAX_VIEWS) {
1124                 pr_err("Registering view %s/%s would exceed the maximum "
1125                        "number of views %i\n", id->name, view->name, i);
1126                 rc = -1;
1127         } else {
1128                 id->views[i] = view;
1129                 id->debugfs_entries[i] = pde;
1130         }
1131         spin_unlock_irqrestore(&id->lock, flags);
1132         if (rc)
1133                 debugfs_remove(pde);
1134 out:
1135         return rc;
1136 }
1137 EXPORT_SYMBOL(debug_register_view);
1138 
1139 /**
1140  * debug_unregister_view() - unregisters debug view and removes debugfs
1141  *                           dir entry
1142  *
1143  * @id:         handle for debug log
1144  * @view:       pointer to debug view struct
1145  *
1146  * Return:
1147  * -   0  : ok
1148  * -   < 0: Error
1149  */
1150 int debug_unregister_view(debug_info_t *id, struct debug_view *view)
1151 {
1152         struct dentry *dentry = NULL;
1153         unsigned long flags;
1154         int i, rc = 0;
1155 
1156         if (!id)
1157                 goto out;
1158         spin_lock_irqsave(&id->lock, flags);
1159         for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1160                 if (id->views[i] == view)
1161                         break;
1162         }
1163         if (i == DEBUG_MAX_VIEWS) {
1164                 rc = -1;
1165         } else {
1166                 dentry = id->debugfs_entries[i];
1167                 id->views[i] = NULL;
1168                 id->debugfs_entries[i] = NULL;
1169         }
1170         spin_unlock_irqrestore(&id->lock, flags);
1171         debugfs_remove(dentry);
1172 out:
1173         return rc;
1174 }
1175 EXPORT_SYMBOL(debug_unregister_view);
1176 
1177 static inline char *debug_get_user_string(const char __user *user_buf,
1178                                           size_t user_len)
1179 {
1180         char *buffer;
1181 
1182         buffer = kmalloc(user_len + 1, GFP_KERNEL);
1183         if (!buffer)
1184                 return ERR_PTR(-ENOMEM);
1185         if (copy_from_user(buffer, user_buf, user_len) != 0) {
1186                 kfree(buffer);
1187                 return ERR_PTR(-EFAULT);
1188         }
1189         /* got the string, now strip linefeed. */
1190         if (buffer[user_len - 1] == '\n')
1191                 buffer[user_len - 1] = 0;
1192         else
1193                 buffer[user_len] = 0;
1194         return buffer;
1195 }
1196 
1197 static inline int debug_get_uint(char *buf)
1198 {
1199         int rc;
1200 
1201         buf = skip_spaces(buf);
1202         rc = simple_strtoul(buf, &buf, 10);
1203         if (*buf)
1204                 rc = -EINVAL;
1205         return rc;
1206 }
1207 
1208 /*
1209  * functions for debug-views
1210  ***********************************
1211 */
1212 
1213 /*
1214  * prints out actual debug level
1215  */
1216 
1217 static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
1218                                  char *out_buf)
1219 {
1220         return sprintf(out_buf, "%i\n", id->pages_per_area);
1221 }
1222 
1223 /*
1224  * reads new size (number of pages per debug area)
1225  */
1226 
1227 static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
1228                                 struct file *file, const char __user *user_buf,
1229                                 size_t user_len, loff_t *offset)
1230 {
1231         int rc, new_pages;
1232         char *str;
1233 
1234         if (user_len > 0x10000)
1235                 user_len = 0x10000;
1236         if (*offset != 0) {
1237                 rc = -EPIPE;
1238                 goto out;
1239         }
1240         str = debug_get_user_string(user_buf, user_len);
1241         if (IS_ERR(str)) {
1242                 rc = PTR_ERR(str);
1243                 goto out;
1244         }
1245         new_pages = debug_get_uint(str);
1246         if (new_pages < 0) {
1247                 rc = -EINVAL;
1248                 goto free_str;
1249         }
1250         rc = debug_set_size(id, id->nr_areas, new_pages);
1251         if (rc != 0) {
1252                 rc = -EINVAL;
1253                 goto free_str;
1254         }
1255         rc = user_len;
1256 free_str:
1257         kfree(str);
1258 out:
1259         *offset += user_len;
1260         return rc;              /* number of input characters */
1261 }
1262 
1263 /*
1264  * prints out actual debug level
1265  */
1266 static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
1267                                  char *out_buf)
1268 {
1269         int rc = 0;
1270 
1271         if (id->level == DEBUG_OFF_LEVEL)
1272                 rc = sprintf(out_buf, "-\n");
1273         else
1274                 rc = sprintf(out_buf, "%i\n", id->level);
1275         return rc;
1276 }
1277 
1278 /*
1279  * reads new debug level
1280  */
1281 static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
1282                                 struct file *file, const char __user *user_buf,
1283                                 size_t user_len, loff_t *offset)
1284 {
1285         int rc, new_level;
1286         char *str;
1287 
1288         if (user_len > 0x10000)
1289                 user_len = 0x10000;
1290         if (*offset != 0) {
1291                 rc = -EPIPE;
1292                 goto out;
1293         }
1294         str = debug_get_user_string(user_buf, user_len);
1295         if (IS_ERR(str)) {
1296                 rc = PTR_ERR(str);
1297                 goto out;
1298         }
1299         if (str[0] == '-') {
1300                 debug_set_level(id, DEBUG_OFF_LEVEL);
1301                 rc = user_len;
1302                 goto free_str;
1303         } else {
1304                 new_level = debug_get_uint(str);
1305         }
1306         if (new_level < 0) {
1307                 pr_warn("%s is not a valid level for a debug feature\n", str);
1308                 rc = -EINVAL;
1309         } else {
1310                 debug_set_level(id, new_level);
1311                 rc = user_len;
1312         }
1313 free_str:
1314         kfree(str);
1315 out:
1316         *offset += user_len;
1317         return rc;              /* number of input characters */
1318 }
1319 
1320 /*
1321  * flushes debug areas
1322  */
1323 static void debug_flush(debug_info_t *id, int area)
1324 {
1325         unsigned long flags;
1326         int i, j;
1327 
1328         if (!id || !id->areas)
1329                 return;
1330         spin_lock_irqsave(&id->lock, flags);
1331         if (area == DEBUG_FLUSH_ALL) {
1332                 id->active_area = 0;
1333                 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1334                 for (i = 0; i < id->nr_areas; i++) {
1335                         id->active_pages[i] = 0;
1336                         for (j = 0; j < id->pages_per_area; j++)
1337                                 memset(id->areas[i][j], 0, PAGE_SIZE);
1338                 }
1339         } else if (area >= 0 && area < id->nr_areas) {
1340                 id->active_entries[area] = 0;
1341                 id->active_pages[area] = 0;
1342                 for (i = 0; i < id->pages_per_area; i++)
1343                         memset(id->areas[area][i], 0, PAGE_SIZE);
1344         }
1345         spin_unlock_irqrestore(&id->lock, flags);
1346 }
1347 
1348 /*
1349  * view function: flushes debug areas
1350  */
1351 static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
1352                                 struct file *file, const char __user *user_buf,
1353                                 size_t user_len, loff_t *offset)
1354 {
1355         char input_buf[1];
1356         int rc = user_len;
1357 
1358         if (user_len > 0x10000)
1359                 user_len = 0x10000;
1360         if (*offset != 0) {
1361                 rc = -EPIPE;
1362                 goto out;
1363         }
1364         if (copy_from_user(input_buf, user_buf, 1)) {
1365                 rc = -EFAULT;
1366                 goto out;
1367         }
1368         if (input_buf[0] == '-') {
1369                 debug_flush(id, DEBUG_FLUSH_ALL);
1370                 goto out;
1371         }
1372         if (isdigit(input_buf[0])) {
1373                 int area = ((int) input_buf[0] - (int) '0');
1374 
1375                 debug_flush(id, area);
1376                 goto out;
1377         }
1378 
1379         pr_info("Flushing debug data failed because %c is not a valid "
1380                  "area\n", input_buf[0]);
1381 
1382 out:
1383         *offset += user_len;
1384         return rc;              /* number of input characters */
1385 }
1386 
1387 /*
1388  * prints debug header in raw format
1389  */
1390 static int debug_raw_header_fn(debug_info_t *id, struct debug_view *view,
1391                                int area, debug_entry_t *entry, char *out_buf)
1392 {
1393         int rc;
1394 
1395         rc = sizeof(debug_entry_t);
1396         memcpy(out_buf, entry, sizeof(debug_entry_t));
1397         return rc;
1398 }
1399 
1400 /*
1401  * prints debug data in raw format
1402  */
1403 static int debug_raw_format_fn(debug_info_t *id, struct debug_view *view,
1404                                char *out_buf, const char *in_buf)
1405 {
1406         int rc;
1407 
1408         rc = id->buf_size;
1409         memcpy(out_buf, in_buf, id->buf_size);
1410         return rc;
1411 }
1412 
1413 /*
1414  * prints debug data in hex/ascii format
1415  */
1416 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
1417                                      char *out_buf, const char *in_buf)
1418 {
1419         int i, rc = 0;
1420 
1421         for (i = 0; i < id->buf_size; i++)
1422                 rc += sprintf(out_buf + rc, "%02x ", ((unsigned char *) in_buf)[i]);
1423         rc += sprintf(out_buf + rc, "| ");
1424         for (i = 0; i < id->buf_size; i++) {
1425                 unsigned char c = in_buf[i];
1426 
1427                 if (isascii(c) && isprint(c))
1428                         rc += sprintf(out_buf + rc, "%c", c);
1429                 else
1430                         rc += sprintf(out_buf + rc, ".");
1431         }
1432         rc += sprintf(out_buf + rc, "\n");
1433         return rc;
1434 }
1435 
1436 /*
1437  * prints header for debug entry
1438  */
1439 int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
1440                          int area, debug_entry_t *entry, char *out_buf)
1441 {
1442         unsigned long base, sec, usec;
1443         unsigned long caller;
1444         unsigned int level;
1445         char *except_str;
1446         int rc = 0;
1447 
1448         level = entry->id.fields.level;
1449         base = (*(unsigned long *) &tod_clock_base[0]) >> 4;
1450         sec = (entry->id.stck >> 12) + base - (TOD_UNIX_EPOCH >> 12);
1451         usec = do_div(sec, USEC_PER_SEC);
1452 
1453         if (entry->id.fields.exception)
1454                 except_str = "*";
1455         else
1456                 except_str = "-";
1457         caller = (unsigned long) entry->caller;
1458         rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %02i %pK  ",
1459                       area, sec, usec, level, except_str,
1460                       entry->id.fields.cpuid, (void *)caller);
1461         return rc;
1462 }
1463 EXPORT_SYMBOL(debug_dflt_header_fn);
1464 
1465 /*
1466  * prints debug data sprintf-formated:
1467  * debug_sprinf_event/exception calls must be used together with this view
1468  */
1469 
1470 #define DEBUG_SPRINTF_MAX_ARGS 10
1471 
1472 static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
1473                                    char *out_buf, debug_sprintf_entry_t *curr_event)
1474 {
1475         int num_longs, num_used_args = 0, i, rc = 0;
1476         int index[DEBUG_SPRINTF_MAX_ARGS];
1477 
1478         /* count of longs fit into one entry */
1479         num_longs = id->buf_size / sizeof(long);
1480 
1481         if (num_longs < 1)
1482                 goto out; /* bufsize of entry too small */
1483         if (num_longs == 1) {
1484                 /* no args, we use only the string */
1485                 strcpy(out_buf, curr_event->string);
1486                 rc = strlen(curr_event->string);
1487                 goto out;
1488         }
1489 
1490         /* number of arguments used for sprintf (without the format string) */
1491         num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1492 
1493         memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1494 
1495         for (i = 0; i < num_used_args; i++)
1496                 index[i] = i;
1497 
1498         rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1499                      curr_event->args[index[1]], curr_event->args[index[2]],
1500                      curr_event->args[index[3]], curr_event->args[index[4]],
1501                      curr_event->args[index[5]], curr_event->args[index[6]],
1502                      curr_event->args[index[7]], curr_event->args[index[8]],
1503                      curr_event->args[index[9]]);
1504 out:
1505         return rc;
1506 }
1507 
1508 /*
1509  * debug_init:
1510  * - is called exactly once to initialize the debug feature
1511  */
1512 static int __init debug_init(void)
1513 {
1514         s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
1515         mutex_lock(&debug_mutex);
1516         debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1517         initialized = 1;
1518         mutex_unlock(&debug_mutex);
1519         return 0;
1520 }
1521 postcore_initcall(debug_init);
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root/arch/s390/kernel/debug.c

DEFINITIONS
