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debug.c
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1 /*
2  * S/390 debug facility
3  *
4  * Copyright IBM Corp. 1999, 2012
5  *
6  * Author(s): Michael Holzheu ([email protected]),
7  * Holger Smolinski ([email protected])
8  *
9  * Bugreports to: <[email protected]>
10  */
11 
12 #define KMSG_COMPONENT "s390dbf"
13 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
14 
15 #include <linux/stddef.h>
16 #include <linux/kernel.h>
17 #include <linux/errno.h>
18 #include <linux/slab.h>
19 #include <linux/ctype.h>
20 #include <linux/string.h>
21 #include <linux/sysctl.h>
22 #include <asm/uaccess.h>
23 #include <linux/module.h>
24 #include <linux/init.h>
25 #include <linux/fs.h>
26 #include <linux/debugfs.h>
27 
28 #include <asm/debug.h>
29 
30 #define DEBUG_PROLOG_ENTRY -1
31 
32 #define ALL_AREAS 0 /* copy all debug areas */
33 #define NO_AREAS 1 /* copy no debug areas */
34 
35 /* typedefs */
36 
37 typedef struct file_private_info {
38  loff_t offset; /* offset of last read in file */
39  int act_area; /* number of last formated area */
40  int act_page; /* act page in given area */
41  int act_entry; /* last formated entry (offset */
42  /* relative to beginning of last */
43  /* formated page) */
44  size_t act_entry_offset; /* up to this offset we copied */
45  /* in last read the last formated */
46  /* entry to userland */
47  char temp_buf[2048]; /* buffer for output */
48  debug_info_t *debug_info_org; /* original debug information */
49  debug_info_t *debug_info_snap; /* snapshot of debug information */
50  struct debug_view *view; /* used view of debug info */
52 
53 typedef struct
54 {
55  char *string;
56  /*
57  * This assumes that all args are converted into longs
58  * on L/390 this is the case for all types of parameter
59  * except of floats, and long long (32 bit)
60  *
61  */
62  long args[0];
64 
65 
66 /* internal function prototyes */
67 
68 static int debug_init(void);
69 static ssize_t debug_output(struct file *file, char __user *user_buf,
70  size_t user_len, loff_t * offset);
71 static ssize_t debug_input(struct file *file, const char __user *user_buf,
72  size_t user_len, loff_t * offset);
73 static int debug_open(struct inode *inode, struct file *file);
74 static int debug_close(struct inode *inode, struct file *file);
75 static debug_info_t *debug_info_create(const char *name, int pages_per_area,
76  int nr_areas, int buf_size, umode_t mode);
77 static void debug_info_get(debug_info_t *);
78 static void debug_info_put(debug_info_t *);
79 static int debug_prolog_level_fn(debug_info_t * id,
80  struct debug_view *view, char *out_buf);
81 static int debug_input_level_fn(debug_info_t * id, struct debug_view *view,
82  struct file *file, const char __user *user_buf,
83  size_t user_buf_size, loff_t * offset);
84 static int debug_prolog_pages_fn(debug_info_t * id,
85  struct debug_view *view, char *out_buf);
86 static int debug_input_pages_fn(debug_info_t * id, struct debug_view *view,
87  struct file *file, const char __user *user_buf,
88  size_t user_buf_size, loff_t * offset);
89 static int debug_input_flush_fn(debug_info_t * id, struct debug_view *view,
90  struct file *file, const char __user *user_buf,
91  size_t user_buf_size, loff_t * offset);
92 static int debug_hex_ascii_format_fn(debug_info_t * id, struct debug_view *view,
93  char *out_buf, const char *in_buf);
94 static int debug_raw_format_fn(debug_info_t * id,
95  struct debug_view *view, char *out_buf,
96  const char *in_buf);
97 static int debug_raw_header_fn(debug_info_t * id, struct debug_view *view,
98  int area, debug_entry_t * entry, char *out_buf);
99 
100 static int debug_sprintf_format_fn(debug_info_t * id, struct debug_view *view,
101  char *out_buf, debug_sprintf_entry_t *curr_event);
102 
103 /* globals */
104 
106  "raw",
107  NULL,
108  &debug_raw_header_fn,
109  &debug_raw_format_fn,
110  NULL,
111  NULL
112 };
113 EXPORT_SYMBOL(debug_raw_view);
114 
116  "hex_ascii",
117  NULL,
119  &debug_hex_ascii_format_fn,
120  NULL,
121  NULL
122 };
123 EXPORT_SYMBOL(debug_hex_ascii_view);
124 
125 static struct debug_view debug_level_view = {
126  "level",
127  &debug_prolog_level_fn,
128  NULL,
129  NULL,
130  &debug_input_level_fn,
131  NULL
132 };
133 
134 static struct debug_view debug_pages_view = {
135  "pages",
136  &debug_prolog_pages_fn,
137  NULL,
138  NULL,
139  &debug_input_pages_fn,
140  NULL
141 };
142 
143 static struct debug_view debug_flush_view = {
144  "flush",
145  NULL,
146  NULL,
147  NULL,
148  &debug_input_flush_fn,
149  NULL
150 };
151 
153  "sprintf",
154  NULL,
156  (debug_format_proc_t*)&debug_sprintf_format_fn,
157  NULL,
158  NULL
159 };
160 EXPORT_SYMBOL(debug_sprintf_view);
161 
162 /* used by dump analysis tools to determine version of debug feature */
163 static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
164 
165 /* static globals */
166 
167 static debug_info_t *debug_area_first = NULL;
168 static debug_info_t *debug_area_last = NULL;
169 static DEFINE_MUTEX(debug_mutex);
170 
171 static int initialized;
172 static int debug_critical;
173 
174 static const struct file_operations debug_file_ops = {
175  .owner = THIS_MODULE,
176  .read = debug_output,
177  .write = debug_input,
178  .open = debug_open,
179  .release = debug_close,
180  .llseek = no_llseek,
181 };
182 
183 static struct dentry *debug_debugfs_root_entry;
184 
185 /* functions */
186 
187 /*
188  * debug_areas_alloc
189  * - Debug areas are implemented as a threedimensonal array:
190  * areas[areanumber][pagenumber][pageoffset]
191  */
192 
193 static debug_entry_t***
194 debug_areas_alloc(int pages_per_area, int nr_areas)
195 {
196  debug_entry_t*** areas;
197  int i,j;
198 
199  areas = kmalloc(nr_areas *
200  sizeof(debug_entry_t**),
201  GFP_KERNEL);
202  if (!areas)
203  goto fail_malloc_areas;
204  for (i = 0; i < nr_areas; i++) {
205  areas[i] = kmalloc(pages_per_area *
206  sizeof(debug_entry_t*),GFP_KERNEL);
207  if (!areas[i]) {
208  goto fail_malloc_areas2;
209  }
210  for(j = 0; j < pages_per_area; j++) {
211  areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
212  if(!areas[i][j]) {
213  for(j--; j >=0 ; j--) {
214  kfree(areas[i][j]);
215  }
216  kfree(areas[i]);
217  goto fail_malloc_areas2;
218  }
219  }
220  }
221  return areas;
222 
223 fail_malloc_areas2:
224  for(i--; i >= 0; i--){
225  for(j=0; j < pages_per_area;j++){
226  kfree(areas[i][j]);
227  }
228  kfree(areas[i]);
229  }
230  kfree(areas);
231 fail_malloc_areas:
232  return NULL;
233 
234 }
235 
236 
237 /*
238  * debug_info_alloc
239  * - alloc new debug-info
240  */
241 
242 static debug_info_t*
243 debug_info_alloc(const char *name, int pages_per_area, int nr_areas,
244  int buf_size, int level, int mode)
245 {
246  debug_info_t* rc;
247 
248  /* alloc everything */
249 
250  rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
251  if(!rc)
252  goto fail_malloc_rc;
253  rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
254  if(!rc->active_entries)
255  goto fail_malloc_active_entries;
256  rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
257  if(!rc->active_pages)
258  goto fail_malloc_active_pages;
259  if((mode == ALL_AREAS) && (pages_per_area != 0)){
260  rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
261  if(!rc->areas)
262  goto fail_malloc_areas;
263  } else {
264  rc->areas = NULL;
265  }
266 
267  /* initialize members */
268 
269  spin_lock_init(&rc->lock);
270  rc->pages_per_area = pages_per_area;
271  rc->nr_areas = nr_areas;
272  rc->active_area = 0;
273  rc->level = level;
274  rc->buf_size = buf_size;
275  rc->entry_size = sizeof(debug_entry_t) + buf_size;
276  strlcpy(rc->name, name, sizeof(rc->name));
277  memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
279  sizeof(struct dentry*));
280  atomic_set(&(rc->ref_count), 0);
281 
282  return rc;
283 
284 fail_malloc_areas:
285  kfree(rc->active_pages);
286 fail_malloc_active_pages:
287  kfree(rc->active_entries);
288 fail_malloc_active_entries:
289  kfree(rc);
290 fail_malloc_rc:
291  return NULL;
292 }
293 
294 /*
295  * debug_areas_free
296  * - free all debug areas
297  */
298 
299 static void
300 debug_areas_free(debug_info_t* db_info)
301 {
302  int i,j;
303 
304  if(!db_info->areas)
305  return;
306  for (i = 0; i < db_info->nr_areas; i++) {
307  for(j = 0; j < db_info->pages_per_area; j++) {
308  kfree(db_info->areas[i][j]);
309  }
310  kfree(db_info->areas[i]);
311  }
312  kfree(db_info->areas);
313  db_info->areas = NULL;
314 }
315 
316 /*
317  * debug_info_free
318  * - free memory debug-info
319  */
320 
321 static void
322 debug_info_free(debug_info_t* db_info){
323  debug_areas_free(db_info);
324  kfree(db_info->active_entries);
325  kfree(db_info->active_pages);
326  kfree(db_info);
327 }
328 
329 /*
330  * debug_info_create
331  * - create new debug-info
332  */
333 
334 static debug_info_t*
335 debug_info_create(const char *name, int pages_per_area, int nr_areas,
336  int buf_size, umode_t mode)
337 {
338  debug_info_t* rc;
339 
340  rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
342  if(!rc)
343  goto out;
344 
345  rc->mode = mode & ~S_IFMT;
346 
347  /* create root directory */
349  debug_debugfs_root_entry);
350 
351  /* append new element to linked list */
352  if (!debug_area_first) {
353  /* first element in list */
354  debug_area_first = rc;
355  rc->prev = NULL;
356  } else {
357  /* append element to end of list */
358  debug_area_last->next = rc;
359  rc->prev = debug_area_last;
360  }
361  debug_area_last = rc;
362  rc->next = NULL;
363 
364  debug_info_get(rc);
365 out:
366  return rc;
367 }
368 
369 /*
370  * debug_info_copy
371  * - copy debug-info
372  */
373 
374 static debug_info_t*
375 debug_info_copy(debug_info_t* in, int mode)
376 {
377  int i,j;
378  debug_info_t* rc;
379  unsigned long flags;
380 
381  /* get a consistent copy of the debug areas */
382  do {
383  rc = debug_info_alloc(in->name, in->pages_per_area,
384  in->nr_areas, in->buf_size, in->level, mode);
385  spin_lock_irqsave(&in->lock, flags);
386  if(!rc)
387  goto out;
388  /* has something changed in the meantime ? */
389  if((rc->pages_per_area == in->pages_per_area) &&
390  (rc->nr_areas == in->nr_areas)) {
391  break;
392  }
393  spin_unlock_irqrestore(&in->lock, flags);
394  debug_info_free(rc);
395  } while (1);
396 
397  if (mode == NO_AREAS)
398  goto out;
399 
400  for(i = 0; i < in->nr_areas; i++){
401  for(j = 0; j < in->pages_per_area; j++) {
402  memcpy(rc->areas[i][j], in->areas[i][j],PAGE_SIZE);
403  }
404  }
405 out:
406  spin_unlock_irqrestore(&in->lock, flags);
407  return rc;
408 }
409 
410 /*
411  * debug_info_get
412  * - increments reference count for debug-info
413  */
414 
415 static void
416 debug_info_get(debug_info_t * db_info)
417 {
418  if (db_info)
419  atomic_inc(&db_info->ref_count);
420 }
421 
422 /*
423  * debug_info_put:
424  * - decreases reference count for debug-info and frees it if necessary
425  */
426 
427 static void
428 debug_info_put(debug_info_t *db_info)
429 {
430  int i;
431 
432  if (!db_info)
433  return;
434  if (atomic_dec_and_test(&db_info->ref_count)) {
435  for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
436  if (!db_info->views[i])
437  continue;
438  debugfs_remove(db_info->debugfs_entries[i]);
439  }
441  if(db_info == debug_area_first)
442  debug_area_first = db_info->next;
443  if(db_info == debug_area_last)
444  debug_area_last = db_info->prev;
445  if(db_info->prev) db_info->prev->next = db_info->next;
446  if(db_info->next) db_info->next->prev = db_info->prev;
447  debug_info_free(db_info);
448  }
449 }
450 
451 /*
452  * debug_format_entry:
453  * - format one debug entry and return size of formated data
454  */
455 
456 static int
457 debug_format_entry(file_private_info_t *p_info)
458 {
459  debug_info_t *id_snap = p_info->debug_info_snap;
460  struct debug_view *view = p_info->view;
461  debug_entry_t *act_entry;
462  size_t len = 0;
463  if(p_info->act_entry == DEBUG_PROLOG_ENTRY){
464  /* print prolog */
465  if (view->prolog_proc)
466  len += view->prolog_proc(id_snap,view,p_info->temp_buf);
467  goto out;
468  }
469  if (!id_snap->areas) /* this is true, if we have a prolog only view */
470  goto out; /* or if 'pages_per_area' is 0 */
471  act_entry = (debug_entry_t *) ((char*)id_snap->areas[p_info->act_area]
472  [p_info->act_page] + p_info->act_entry);
473 
474  if (act_entry->id.stck == 0LL)
475  goto out; /* empty entry */
476  if (view->header_proc)
477  len += view->header_proc(id_snap, view, p_info->act_area,
478  act_entry, p_info->temp_buf + len);
479  if (view->format_proc)
480  len += view->format_proc(id_snap, view, p_info->temp_buf + len,
481  DEBUG_DATA(act_entry));
482 out:
483  return len;
484 }
485 
486 /*
487  * debug_next_entry:
488  * - goto next entry in p_info
489  */
490 
491 static inline int
492 debug_next_entry(file_private_info_t *p_info)
493 {
494  debug_info_t *id;
495 
496  id = p_info->debug_info_snap;
497  if(p_info->act_entry == DEBUG_PROLOG_ENTRY){
498  p_info->act_entry = 0;
499  p_info->act_page = 0;
500  goto out;
501  }
502  if(!id->areas)
503  return 1;
504  p_info->act_entry += id->entry_size;
505  /* switch to next page, if we reached the end of the page */
506  if (p_info->act_entry > (PAGE_SIZE - id->entry_size)){
507  /* next page */
508  p_info->act_entry = 0;
509  p_info->act_page += 1;
510  if((p_info->act_page % id->pages_per_area) == 0) {
511  /* next area */
512  p_info->act_area++;
513  p_info->act_page=0;
514  }
515  if(p_info->act_area >= id->nr_areas)
516  return 1;
517  }
518 out:
519  return 0;
520 }
521 
522 /*
523  * debug_output:
524  * - called for user read()
525  * - copies formated debug entries to the user buffer
526  */
527 
528 static ssize_t
529 debug_output(struct file *file, /* file descriptor */
530  char __user *user_buf, /* user buffer */
531  size_t len, /* length of buffer */
532  loff_t *offset) /* offset in the file */
533 {
534  size_t count = 0;
535  size_t entry_offset;
536  file_private_info_t *p_info;
537 
538  p_info = ((file_private_info_t *) file->private_data);
539  if (*offset != p_info->offset)
540  return -EPIPE;
541  if(p_info->act_area >= p_info->debug_info_snap->nr_areas)
542  return 0;
543  entry_offset = p_info->act_entry_offset;
544  while(count < len){
545  int formatted_line_size;
546  int formatted_line_residue;
547  int user_buf_residue;
548  size_t copy_size;
549 
550  formatted_line_size = debug_format_entry(p_info);
551  formatted_line_residue = formatted_line_size - entry_offset;
552  user_buf_residue = len-count;
553  copy_size = min(user_buf_residue, formatted_line_residue);
554  if(copy_size){
555  if (copy_to_user(user_buf + count, p_info->temp_buf
556  + entry_offset, copy_size))
557  return -EFAULT;
558  count += copy_size;
559  entry_offset += copy_size;
560  }
561  if(copy_size == formatted_line_residue){
562  entry_offset = 0;
563  if(debug_next_entry(p_info))
564  goto out;
565  }
566  }
567 out:
568  p_info->offset = *offset + count;
569  p_info->act_entry_offset = entry_offset;
570  *offset = p_info->offset;
571  return count;
572 }
573 
574 /*
575  * debug_input:
576  * - called for user write()
577  * - calls input function of view
578  */
579 
580 static ssize_t
581 debug_input(struct file *file, const char __user *user_buf, size_t length,
582  loff_t *offset)
583 {
584  int rc = 0;
585  file_private_info_t *p_info;
586 
587  mutex_lock(&debug_mutex);
588  p_info = ((file_private_info_t *) file->private_data);
589  if (p_info->view->input_proc)
590  rc = p_info->view->input_proc(p_info->debug_info_org,
591  p_info->view, file, user_buf,
592  length, offset);
593  else
594  rc = -EPERM;
595  mutex_unlock(&debug_mutex);
596  return rc; /* number of input characters */
597 }
598 
599 /*
600  * debug_open:
601  * - called for user open()
602  * - copies formated output to private_data area of the file
603  * handle
604  */
605 
606 static int
607 debug_open(struct inode *inode, struct file *file)
608 {
609  int i, rc = 0;
610  file_private_info_t *p_info;
611  debug_info_t *debug_info, *debug_info_snapshot;
612 
613  mutex_lock(&debug_mutex);
614  debug_info = file->f_path.dentry->d_inode->i_private;
615  /* find debug view */
616  for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
617  if (!debug_info->views[i])
618  continue;
619  else if (debug_info->debugfs_entries[i] ==
620  file->f_path.dentry) {
621  goto found; /* found view ! */
622  }
623  }
624  /* no entry found */
625  rc = -EINVAL;
626  goto out;
627 
628 found:
629 
630  /* Make snapshot of current debug areas to get it consistent. */
631  /* To copy all the areas is only needed, if we have a view which */
632  /* formats the debug areas. */
633 
634  if(!debug_info->views[i]->format_proc &&
635  !debug_info->views[i]->header_proc){
636  debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
637  } else {
638  debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
639  }
640 
641  if(!debug_info_snapshot){
642  rc = -ENOMEM;
643  goto out;
644  }
645  p_info = kmalloc(sizeof(file_private_info_t),
646  GFP_KERNEL);
647  if(!p_info){
648  debug_info_free(debug_info_snapshot);
649  rc = -ENOMEM;
650  goto out;
651  }
652  p_info->offset = 0;
653  p_info->debug_info_snap = debug_info_snapshot;
654  p_info->debug_info_org = debug_info;
655  p_info->view = debug_info->views[i];
656  p_info->act_area = 0;
657  p_info->act_page = 0;
658  p_info->act_entry = DEBUG_PROLOG_ENTRY;
659  p_info->act_entry_offset = 0;
660  file->private_data = p_info;
661  debug_info_get(debug_info);
662  nonseekable_open(inode, file);
663 out:
664  mutex_unlock(&debug_mutex);
665  return rc;
666 }
667 
668 /*
669  * debug_close:
670  * - called for user close()
671  * - deletes private_data area of the file handle
672  */
673 
674 static int
675 debug_close(struct inode *inode, struct file *file)
676 {
677  file_private_info_t *p_info;
678  p_info = (file_private_info_t *) file->private_data;
679  if(p_info->debug_info_snap)
680  debug_info_free(p_info->debug_info_snap);
681  debug_info_put(p_info->debug_info_org);
682  kfree(file->private_data);
683  return 0; /* success */
684 }
685 
686 /*
687  * debug_register_mode:
688  * - Creates and initializes debug area for the caller
689  * The mode parameter allows to specify access rights for the s390dbf files
690  * - Returns handle for debug area
691  */
692 
693 debug_info_t *debug_register_mode(const char *name, int pages_per_area,
694  int nr_areas, int buf_size, umode_t mode,
695  uid_t uid, gid_t gid)
696 {
697  debug_info_t *rc = NULL;
698 
699  /* Since debugfs currently does not support uid/gid other than root, */
700  /* we do not allow gid/uid != 0 until we get support for that. */
701  if ((uid != 0) || (gid != 0))
702  pr_warning("Root becomes the owner of all s390dbf files "
703  "in sysfs\n");
704  BUG_ON(!initialized);
705  mutex_lock(&debug_mutex);
706 
707  /* create new debug_info */
708 
709  rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
710  if(!rc)
711  goto out;
712  debug_register_view(rc, &debug_level_view);
713  debug_register_view(rc, &debug_flush_view);
714  debug_register_view(rc, &debug_pages_view);
715 out:
716  if (!rc){
717  pr_err("Registering debug feature %s failed\n", name);
718  }
719  mutex_unlock(&debug_mutex);
720  return rc;
721 }
723 
724 /*
725  * debug_register:
726  * - creates and initializes debug area for the caller
727  * - returns handle for debug area
728  */
729 
730 debug_info_t *debug_register(const char *name, int pages_per_area,
731  int nr_areas, int buf_size)
732 {
733  return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
734  S_IRUSR | S_IWUSR, 0, 0);
735 }
737 
738 /*
739  * debug_unregister:
740  * - give back debug area
741  */
742 
743 void
745 {
746  if (!id)
747  goto out;
748  mutex_lock(&debug_mutex);
749  debug_info_put(id);
750  mutex_unlock(&debug_mutex);
751 
752 out:
753  return;
754 }
756 
757 /*
758  * debug_set_size:
759  * - set area size (number of pages) and number of areas
760  */
761 static int
762 debug_set_size(debug_info_t* id, int nr_areas, int pages_per_area)
763 {
764  unsigned long flags;
765  debug_entry_t *** new_areas;
766  int rc=0;
767 
768  if(!id || (nr_areas <= 0) || (pages_per_area < 0))
769  return -EINVAL;
770  if(pages_per_area > 0){
771  new_areas = debug_areas_alloc(pages_per_area, nr_areas);
772  if(!new_areas) {
773  pr_info("Allocating memory for %i pages failed\n",
774  pages_per_area);
775  rc = -ENOMEM;
776  goto out;
777  }
778  } else {
779  new_areas = NULL;
780  }
781  spin_lock_irqsave(&id->lock,flags);
782  debug_areas_free(id);
783  id->areas = new_areas;
784  id->nr_areas = nr_areas;
785  id->pages_per_area = pages_per_area;
786  id->active_area = 0;
787  memset(id->active_entries,0,sizeof(int)*id->nr_areas);
788  memset(id->active_pages, 0, sizeof(int)*id->nr_areas);
789  spin_unlock_irqrestore(&id->lock,flags);
790  pr_info("%s: set new size (%i pages)\n" ,id->name, pages_per_area);
791 out:
792  return rc;
793 }
794 
795 /*
796  * debug_set_level:
797  * - set actual debug level
798  */
799 
800 void
801 debug_set_level(debug_info_t* id, int new_level)
802 {
803  unsigned long flags;
804  if(!id)
805  return;
806  spin_lock_irqsave(&id->lock,flags);
807  if(new_level == DEBUG_OFF_LEVEL){
808  id->level = DEBUG_OFF_LEVEL;
809  pr_info("%s: switched off\n",id->name);
810  } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
811  pr_info("%s: level %i is out of range (%i - %i)\n",
812  id->name, new_level, 0, DEBUG_MAX_LEVEL);
813  } else {
814  id->level = new_level;
815  }
816  spin_unlock_irqrestore(&id->lock,flags);
817 }
819 
820 /*
821  * proceed_active_entry:
822  * - set active entry to next in the ring buffer
823  */
824 
825 static inline void
826 proceed_active_entry(debug_info_t * id)
827 {
828  if ((id->active_entries[id->active_area] += id->entry_size)
829  > (PAGE_SIZE - id->entry_size)){
830  id->active_entries[id->active_area] = 0;
831  id->active_pages[id->active_area] =
832  (id->active_pages[id->active_area] + 1) %
833  id->pages_per_area;
834  }
835 }
836 
837 /*
838  * proceed_active_area:
839  * - set active area to next in the ring buffer
840  */
841 
842 static inline void
843 proceed_active_area(debug_info_t * id)
844 {
845  id->active_area++;
846  id->active_area = id->active_area % id->nr_areas;
847 }
848 
849 /*
850  * get_active_entry:
851  */
852 
853 static inline debug_entry_t*
854 get_active_entry(debug_info_t * id)
855 {
856  return (debug_entry_t *) (((char *) id->areas[id->active_area]
857  [id->active_pages[id->active_area]]) +
858  id->active_entries[id->active_area]);
859 }
860 
861 /*
862  * debug_finish_entry:
863  * - set timestamp, caller address, cpu number etc.
864  */
865 
866 static inline void
867 debug_finish_entry(debug_info_t * id, debug_entry_t* active, int level,
868  int exception)
869 {
870  active->id.stck = get_clock();
871  active->id.fields.cpuid = smp_processor_id();
872  active->caller = __builtin_return_address(0);
873  active->id.fields.exception = exception;
874  active->id.fields.level = level;
875  proceed_active_entry(id);
876  if(exception)
877  proceed_active_area(id);
878 }
879 
880 static int debug_stoppable=1;
881 static int debug_active=1;
882 
883 #define CTL_S390DBF_STOPPABLE 5678
884 #define CTL_S390DBF_ACTIVE 5679
885 
886 /*
887  * proc handler for the running debug_active sysctl
888  * always allow read, allow write only if debug_stoppable is set or
889  * if debug_active is already off
890  */
891 static int
892 s390dbf_procactive(ctl_table *table, int write,
893  void __user *buffer, size_t *lenp, loff_t *ppos)
894 {
895  if (!write || debug_stoppable || !debug_active)
896  return proc_dointvec(table, write, buffer, lenp, ppos);
897  else
898  return 0;
899 }
900 
901 
902 static struct ctl_table s390dbf_table[] = {
903  {
904  .procname = "debug_stoppable",
905  .data = &debug_stoppable,
906  .maxlen = sizeof(int),
907  .mode = S_IRUGO | S_IWUSR,
909  },
910  {
911  .procname = "debug_active",
912  .data = &debug_active,
913  .maxlen = sizeof(int),
914  .mode = S_IRUGO | S_IWUSR,
915  .proc_handler = s390dbf_procactive,
916  },
917  { }
918 };
919 
920 static struct ctl_table s390dbf_dir_table[] = {
921  {
922  .procname = "s390dbf",
923  .maxlen = 0,
924  .mode = S_IRUGO | S_IXUGO,
925  .child = s390dbf_table,
926  },
927  { }
928 };
929 
930 static struct ctl_table_header *s390dbf_sysctl_header;
931 
932 void
934 {
935  if (debug_stoppable)
936  debug_active = 0;
937 }
939 
941 {
942  debug_critical = 1;
943 }
944 
945 /*
946  * debug_event_common:
947  * - write debug entry with given size
948  */
949 
951 debug_event_common(debug_info_t * id, int level, const void *buf, int len)
952 {
953  unsigned long flags;
955 
956  if (!debug_active || !id->areas)
957  return NULL;
958  if (debug_critical) {
959  if (!spin_trylock_irqsave(&id->lock, flags))
960  return NULL;
961  } else
962  spin_lock_irqsave(&id->lock, flags);
963  active = get_active_entry(id);
964  memset(DEBUG_DATA(active), 0, id->buf_size);
965  memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
966  debug_finish_entry(id, active, level, 0);
967  spin_unlock_irqrestore(&id->lock, flags);
968 
969  return active;
970 }
972 
973 /*
974  * debug_exception_common:
975  * - write debug entry with given size and switch to next debug area
976  */
977 
979 *debug_exception_common(debug_info_t * id, int level, const void *buf, int len)
980 {
981  unsigned long flags;
983 
984  if (!debug_active || !id->areas)
985  return NULL;
986  if (debug_critical) {
987  if (!spin_trylock_irqsave(&id->lock, flags))
988  return NULL;
989  } else
990  spin_lock_irqsave(&id->lock, flags);
991  active = get_active_entry(id);
992  memset(DEBUG_DATA(active), 0, id->buf_size);
993  memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
994  debug_finish_entry(id, active, level, 1);
995  spin_unlock_irqrestore(&id->lock, flags);
996 
997  return active;
998 }
1000 
1001 /*
1002  * counts arguments in format string for sprintf view
1003  */
1004 
1005 static inline int
1006 debug_count_numargs(char *string)
1007 {
1008  int numargs=0;
1009 
1010  while(*string) {
1011  if(*string++=='%')
1012  numargs++;
1013  }
1014  return(numargs);
1015 }
1016 
1017 /*
1018  * debug_sprintf_event:
1019  */
1020 
1022 debug_sprintf_event(debug_info_t* id, int level,char *string,...)
1023 {
1024  va_list ap;
1025  int numargs,idx;
1026  unsigned long flags;
1027  debug_sprintf_entry_t *curr_event;
1029 
1030  if((!id) || (level > id->level))
1031  return NULL;
1032  if (!debug_active || !id->areas)
1033  return NULL;
1034  numargs=debug_count_numargs(string);
1035 
1036  if (debug_critical) {
1037  if (!spin_trylock_irqsave(&id->lock, flags))
1038  return NULL;
1039  } else
1040  spin_lock_irqsave(&id->lock, flags);
1041  active = get_active_entry(id);
1042  curr_event=(debug_sprintf_entry_t *) DEBUG_DATA(active);
1043  va_start(ap,string);
1044  curr_event->string=string;
1045  for(idx=0;idx<min(numargs,(int)(id->buf_size / sizeof(long))-1);idx++)
1046  curr_event->args[idx]=va_arg(ap,long);
1047  va_end(ap);
1048  debug_finish_entry(id, active, level, 0);
1049  spin_unlock_irqrestore(&id->lock, flags);
1050 
1051  return active;
1052 }
1054 
1055 /*
1056  * debug_sprintf_exception:
1057  */
1058 
1060 debug_sprintf_exception(debug_info_t* id, int level,char *string,...)
1061 {
1062  va_list ap;
1063  int numargs,idx;
1064  unsigned long flags;
1065  debug_sprintf_entry_t *curr_event;
1067 
1068  if((!id) || (level > id->level))
1069  return NULL;
1070  if (!debug_active || !id->areas)
1071  return NULL;
1072 
1073  numargs=debug_count_numargs(string);
1074 
1075  if (debug_critical) {
1076  if (!spin_trylock_irqsave(&id->lock, flags))
1077  return NULL;
1078  } else
1079  spin_lock_irqsave(&id->lock, flags);
1080  active = get_active_entry(id);
1081  curr_event=(debug_sprintf_entry_t *)DEBUG_DATA(active);
1082  va_start(ap,string);
1083  curr_event->string=string;
1084  for(idx=0;idx<min(numargs,(int)(id->buf_size / sizeof(long))-1);idx++)
1085  curr_event->args[idx]=va_arg(ap,long);
1086  va_end(ap);
1087  debug_finish_entry(id, active, level, 1);
1088  spin_unlock_irqrestore(&id->lock, flags);
1089 
1090  return active;
1091 }
1093 
1094 /*
1095  * debug_register_view:
1096  */
1097 
1098 int
1100 {
1101  int rc = 0;
1102  int i;
1103  unsigned long flags;
1104  umode_t mode;
1105  struct dentry *pde;
1106 
1107  if (!id)
1108  goto out;
1109  mode = (id->mode | S_IFREG) & ~S_IXUGO;
1110  if (!(view->prolog_proc || view->format_proc || view->header_proc))
1111  mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1112  if (!view->input_proc)
1113  mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1114  pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1115  id , &debug_file_ops);
1116  if (!pde){
1117  pr_err("Registering view %s/%s failed due to out of "
1118  "memory\n", id->name,view->name);
1119  rc = -1;
1120  goto out;
1121  }
1122  spin_lock_irqsave(&id->lock, flags);
1123  for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1124  if (!id->views[i])
1125  break;
1126  }
1127  if (i == DEBUG_MAX_VIEWS) {
1128  pr_err("Registering view %s/%s would exceed the maximum "
1129  "number of views %i\n", id->name, view->name, i);
1130  debugfs_remove(pde);
1131  rc = -1;
1132  } else {
1133  id->views[i] = view;
1134  id->debugfs_entries[i] = pde;
1135  }
1136  spin_unlock_irqrestore(&id->lock, flags);
1137 out:
1138  return rc;
1139 }
1141 
1142 /*
1143  * debug_unregister_view:
1144  */
1145 
1146 int
1148 {
1149  int rc = 0;
1150  int i;
1151  unsigned long flags;
1152 
1153  if (!id)
1154  goto out;
1155  spin_lock_irqsave(&id->lock, flags);
1156  for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1157  if (id->views[i] == view)
1158  break;
1159  }
1160  if (i == DEBUG_MAX_VIEWS)
1161  rc = -1;
1162  else {
1164  id->views[i] = NULL;
1165  }
1166  spin_unlock_irqrestore(&id->lock, flags);
1167 out:
1168  return rc;
1169 }
1171 
1172 static inline char *
1173 debug_get_user_string(const char __user *user_buf, size_t user_len)
1174 {
1175  char* buffer;
1176 
1177  buffer = kmalloc(user_len + 1, GFP_KERNEL);
1178  if (!buffer)
1179  return ERR_PTR(-ENOMEM);
1180  if (copy_from_user(buffer, user_buf, user_len) != 0) {
1181  kfree(buffer);
1182  return ERR_PTR(-EFAULT);
1183  }
1184  /* got the string, now strip linefeed. */
1185  if (buffer[user_len - 1] == '\n')
1186  buffer[user_len - 1] = 0;
1187  else
1188  buffer[user_len] = 0;
1189  return buffer;
1190 }
1191 
1192 static inline int
1193 debug_get_uint(char *buf)
1194 {
1195  int rc;
1196 
1197  buf = skip_spaces(buf);
1198  rc = simple_strtoul(buf, &buf, 10);
1199  if(*buf){
1200  rc = -EINVAL;
1201  }
1202  return rc;
1203 }
1204 
1205 /*
1206  * functions for debug-views
1207  ***********************************
1208 */
1209 
1210 /*
1211  * prints out actual debug level
1212  */
1213 
1214 static int
1215 debug_prolog_pages_fn(debug_info_t * id,
1216  struct debug_view *view, char *out_buf)
1217 {
1218  return sprintf(out_buf, "%i\n", id->pages_per_area);
1219 }
1220 
1221 /*
1222  * reads new size (number of pages per debug area)
1223  */
1224 
1225 static int
1226 debug_input_pages_fn(debug_info_t * id, struct debug_view *view,
1227  struct file *file, const char __user *user_buf,
1228  size_t user_len, loff_t * offset)
1229 {
1230  char *str;
1231  int rc,new_pages;
1232 
1233  if (user_len > 0x10000)
1234  user_len = 0x10000;
1235  if (*offset != 0){
1236  rc = -EPIPE;
1237  goto out;
1238  }
1239  str = debug_get_user_string(user_buf,user_len);
1240  if(IS_ERR(str)){
1241  rc = PTR_ERR(str);
1242  goto out;
1243  }
1244  new_pages = debug_get_uint(str);
1245  if(new_pages < 0){
1246  rc = -EINVAL;
1247  goto free_str;
1248  }
1249  rc = debug_set_size(id,id->nr_areas, new_pages);
1250  if(rc != 0){
1251  rc = -EINVAL;
1252  goto free_str;
1253  }
1254  rc = user_len;
1255 free_str:
1256  kfree(str);
1257 out:
1258  *offset += user_len;
1259  return rc; /* number of input characters */
1260 }
1261 
1262 /*
1263  * prints out actual debug level
1264  */
1265 
1266 static int
1267 debug_prolog_level_fn(debug_info_t * id, struct debug_view *view, char *out_buf)
1268 {
1269  int rc = 0;
1270 
1271  if(id->level == DEBUG_OFF_LEVEL) {
1272  rc = sprintf(out_buf,"-\n");
1273  }
1274  else {
1275  rc = sprintf(out_buf, "%i\n", id->level);
1276  }
1277  return rc;
1278 }
1279 
1280 /*
1281  * reads new debug level
1282  */
1283 
1284 static int
1285 debug_input_level_fn(debug_info_t * id, struct debug_view *view,
1286  struct file *file, const char __user *user_buf,
1287  size_t user_len, loff_t * offset)
1288 {
1289  char *str;
1290  int rc,new_level;
1291 
1292  if (user_len > 0x10000)
1293  user_len = 0x10000;
1294  if (*offset != 0){
1295  rc = -EPIPE;
1296  goto out;
1297  }
1298  str = debug_get_user_string(user_buf,user_len);
1299  if(IS_ERR(str)){
1300  rc = PTR_ERR(str);
1301  goto out;
1302  }
1303  if(str[0] == '-'){
1305  rc = user_len;
1306  goto free_str;
1307  } else {
1308  new_level = debug_get_uint(str);
1309  }
1310  if(new_level < 0) {
1311  pr_warning("%s is not a valid level for a debug "
1312  "feature\n", str);
1313  rc = -EINVAL;
1314  } else {
1315  debug_set_level(id, new_level);
1316  rc = user_len;
1317  }
1318 free_str:
1319  kfree(str);
1320 out:
1321  *offset += user_len;
1322  return rc; /* number of input characters */
1323 }
1324 
1325 
1326 /*
1327  * flushes debug areas
1328  */
1329 
1330 static void debug_flush(debug_info_t* id, int area)
1331 {
1332  unsigned long flags;
1333  int i,j;
1334 
1335  if(!id || !id->areas)
1336  return;
1337  spin_lock_irqsave(&id->lock,flags);
1338  if(area == DEBUG_FLUSH_ALL){
1339  id->active_area = 0;
1340  memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1341  for (i = 0; i < id->nr_areas; i++) {
1342  id->active_pages[i] = 0;
1343  for(j = 0; j < id->pages_per_area; j++) {
1344  memset(id->areas[i][j], 0, PAGE_SIZE);
1345  }
1346  }
1347  } else if(area >= 0 && area < id->nr_areas) {
1348  id->active_entries[area] = 0;
1349  id->active_pages[area] = 0;
1350  for(i = 0; i < id->pages_per_area; i++) {
1351  memset(id->areas[area][i],0,PAGE_SIZE);
1352  }
1353  }
1354  spin_unlock_irqrestore(&id->lock,flags);
1355 }
1356 
1357 /*
1358  * view function: flushes debug areas
1359  */
1360 
1361 static int
1362 debug_input_flush_fn(debug_info_t * id, struct debug_view *view,
1363  struct file *file, const char __user *user_buf,
1364  size_t user_len, loff_t * offset)
1365 {
1366  char input_buf[1];
1367  int rc = user_len;
1368 
1369  if (user_len > 0x10000)
1370  user_len = 0x10000;
1371  if (*offset != 0){
1372  rc = -EPIPE;
1373  goto out;
1374  }
1375  if (copy_from_user(input_buf, user_buf, 1)){
1376  rc = -EFAULT;
1377  goto out;
1378  }
1379  if(input_buf[0] == '-') {
1380  debug_flush(id, DEBUG_FLUSH_ALL);
1381  goto out;
1382  }
1383  if (isdigit(input_buf[0])) {
1384  int area = ((int) input_buf[0] - (int) '0');
1385  debug_flush(id, area);
1386  goto out;
1387  }
1388 
1389  pr_info("Flushing debug data failed because %c is not a valid "
1390  "area\n", input_buf[0]);
1391 
1392 out:
1393  *offset += user_len;
1394  return rc; /* number of input characters */
1395 }
1396 
1397 /*
1398  * prints debug header in raw format
1399  */
1400 
1401 static int
1402 debug_raw_header_fn(debug_info_t * id, struct debug_view *view,
1403  int area, debug_entry_t * entry, char *out_buf)
1404 {
1405  int rc;
1406 
1407  rc = sizeof(debug_entry_t);
1408  memcpy(out_buf,entry,sizeof(debug_entry_t));
1409  return rc;
1410 }
1411 
1412 /*
1413  * prints debug data in raw format
1414  */
1415 
1416 static int
1417 debug_raw_format_fn(debug_info_t * id, struct debug_view *view,
1418  char *out_buf, const char *in_buf)
1419 {
1420  int rc;
1421 
1422  rc = id->buf_size;
1423  memcpy(out_buf, in_buf, id->buf_size);
1424  return rc;
1425 }
1426 
1427 /*
1428  * prints debug data in hex/ascii format
1429  */
1430 
1431 static int
1432 debug_hex_ascii_format_fn(debug_info_t * id, struct debug_view *view,
1433  char *out_buf, const char *in_buf)
1434 {
1435  int i, rc = 0;
1436 
1437  for (i = 0; i < id->buf_size; i++) {
1438  rc += sprintf(out_buf + rc, "%02x ",
1439  ((unsigned char *) in_buf)[i]);
1440  }
1441  rc += sprintf(out_buf + rc, "| ");
1442  for (i = 0; i < id->buf_size; i++) {
1443  unsigned char c = in_buf[i];
1444  if (isascii(c) && isprint(c))
1445  rc += sprintf(out_buf + rc, "%c", c);
1446  else
1447  rc += sprintf(out_buf + rc, ".");
1448  }
1449  rc += sprintf(out_buf + rc, "\n");
1450  return rc;
1451 }
1452 
1453 /*
1454  * prints header for debug entry
1455  */
1456 
1457 int
1459  int area, debug_entry_t * entry, char *out_buf)
1460 {
1461  struct timespec time_spec;
1462  char *except_str;
1463  unsigned long caller;
1464  int rc = 0;
1465  unsigned int level;
1466 
1467  level = entry->id.fields.level;
1468  stck_to_timespec(entry->id.stck, &time_spec);
1469 
1470  if (entry->id.fields.exception)
1471  except_str = "*";
1472  else
1473  except_str = "-";
1474  caller = ((unsigned long) entry->caller) & PSW_ADDR_INSN;
1475  rc += sprintf(out_buf, "%02i %011lu:%06lu %1u %1s %02i %p ",
1476  area, time_spec.tv_sec, time_spec.tv_nsec / 1000, level,
1477  except_str, entry->id.fields.cpuid, (void *) caller);
1478  return rc;
1479 }
1480 EXPORT_SYMBOL(debug_dflt_header_fn);
1481 
1482 /*
1483  * prints debug data sprintf-formated:
1484  * debug_sprinf_event/exception calls must be used together with this view
1485  */
1486 
1487 #define DEBUG_SPRINTF_MAX_ARGS 10
1488 
1489 static int
1490 debug_sprintf_format_fn(debug_info_t * id, struct debug_view *view,
1491  char *out_buf, debug_sprintf_entry_t *curr_event)
1492 {
1493  int num_longs, num_used_args = 0,i, rc = 0;
1495 
1496  /* count of longs fit into one entry */
1497  num_longs = id->buf_size / sizeof(long);
1498 
1499  if(num_longs < 1)
1500  goto out; /* bufsize of entry too small */
1501  if(num_longs == 1) {
1502  /* no args, we use only the string */
1503  strcpy(out_buf, curr_event->string);
1504  rc = strlen(curr_event->string);
1505  goto out;
1506  }
1507 
1508  /* number of arguments used for sprintf (without the format string) */
1509  num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1510 
1511  memset(index,0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1512 
1513  for(i = 0; i < num_used_args; i++)
1514  index[i] = i;
1515 
1516  rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1517  curr_event->args[index[1]], curr_event->args[index[2]],
1518  curr_event->args[index[3]], curr_event->args[index[4]],
1519  curr_event->args[index[5]], curr_event->args[index[6]],
1520  curr_event->args[index[7]], curr_event->args[index[8]],
1521  curr_event->args[index[9]]);
1522 
1523 out:
1524 
1525  return rc;
1526 }
1527 
1528 /*
1529  * debug_init:
1530  * - is called exactly once to initialize the debug feature
1531  */
1532 static int __init debug_init(void)
1533 {
1534  s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
1535  mutex_lock(&debug_mutex);
1536  debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1537  initialized = 1;
1538  mutex_unlock(&debug_mutex);
1539  return 0;
1540 }
1541 postcore_initcall(debug_init);