1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * S/390 debug facility
4 *
5 * Copyright IBM Corp. 1999, 2020
6 *
7 * Author(s): Michael Holzheu (holzheu@de.ibm.com),
8 * Holger Smolinski (Holger.Smolinski@de.ibm.com)
9 *
10 * Bugreports to: <Linux390@de.ibm.com>
11 */
12
13 #define KMSG_COMPONENT "s390dbf"
14 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
15
16 #include <linux/stddef.h>
17 #include <linux/kernel.h>
18 #include <linux/errno.h>
19 #include <linux/slab.h>
20 #include <linux/ctype.h>
21 #include <linux/string.h>
22 #include <linux/sysctl.h>
23 #include <linux/uaccess.h>
24 #include <linux/export.h>
25 #include <linux/init.h>
26 #include <linux/fs.h>
27 #include <linux/minmax.h>
28 #include <linux/debugfs.h>
29
30 #include <asm/debug.h>
31
32 #define DEBUG_PROLOG_ENTRY -1
33
34 #define ALL_AREAS 0 /* copy all debug areas */
35 #define NO_AREAS 1 /* copy no debug areas */
36
37 /* typedefs */
38
39 typedef struct file_private_info {
40 loff_t offset; /* offset of last read in file */
41 int act_area; /* number of last formated area */
42 int act_page; /* act page in given area */
43 int act_entry; /* last formated entry (offset */
44 /* relative to beginning of last */
45 /* formated page) */
46 size_t act_entry_offset; /* up to this offset we copied */
47 /* in last read the last formated */
48 /* entry to userland */
49 char temp_buf[2048]; /* buffer for output */
50 debug_info_t *debug_info_org; /* original debug information */
51 debug_info_t *debug_info_snap; /* snapshot of debug information */
52 struct debug_view *view; /* used view of debug info */
53 } file_private_info_t;
54
55 typedef struct {
56 char *string;
57 /*
58 * This assumes that all args are converted into longs
59 * on L/390 this is the case for all types of parameter
60 * except of floats, and long long (32 bit)
61 *
62 */
63 long args[];
64 } debug_sprintf_entry_t;
65
66 /* internal function prototyes */
67
68 static int debug_init(void);
69 static ssize_t debug_output(struct file *file, char __user *user_buf,
70 size_t user_len, loff_t *offset);
71 static ssize_t debug_input(struct file *file, const char __user *user_buf,
72 size_t user_len, loff_t *offset);
73 static int debug_open(struct inode *inode, struct file *file);
74 static int debug_close(struct inode *inode, struct file *file);
75 static debug_info_t *debug_info_create(const char *name, int pages_per_area,
76 int nr_areas, int buf_size, umode_t mode);
77 static void debug_info_get(debug_info_t *);
78 static void debug_info_put(debug_info_t *);
79 static int debug_prolog_level_fn(debug_info_t *id,
80 struct debug_view *view, char *out_buf);
81 static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
82 struct file *file, const char __user *user_buf,
83 size_t user_buf_size, loff_t *offset);
84 static int debug_prolog_pages_fn(debug_info_t *id,
85 struct debug_view *view, char *out_buf);
86 static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
87 struct file *file, const char __user *user_buf,
88 size_t user_buf_size, loff_t *offset);
89 static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
90 struct file *file, const char __user *user_buf,
91 size_t user_buf_size, loff_t *offset);
92 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
93 char *out_buf, const char *in_buf);
94 static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
95 char *out_buf, const char *inbuf);
96 static void debug_areas_swap(debug_info_t *a, debug_info_t *b);
97 static void debug_events_append(debug_info_t *dest, debug_info_t *src);
98
99 /* globals */
100
101 struct debug_view debug_hex_ascii_view = {
102 "hex_ascii",
103 NULL,
104 &debug_dflt_header_fn,
105 &debug_hex_ascii_format_fn,
106 NULL,
107 NULL
108 };
109 EXPORT_SYMBOL(debug_hex_ascii_view);
110
111 static struct debug_view debug_level_view = {
112 "level",
113 &debug_prolog_level_fn,
114 NULL,
115 NULL,
116 &debug_input_level_fn,
117 NULL
118 };
119
120 static struct debug_view debug_pages_view = {
121 "pages",
122 &debug_prolog_pages_fn,
123 NULL,
124 NULL,
125 &debug_input_pages_fn,
126 NULL
127 };
128
129 static struct debug_view debug_flush_view = {
130 "flush",
131 NULL,
132 NULL,
133 NULL,
134 &debug_input_flush_fn,
135 NULL
136 };
137
138 struct debug_view debug_sprintf_view = {
139 "sprintf",
140 NULL,
141 &debug_dflt_header_fn,
142 &debug_sprintf_format_fn,
143 NULL,
144 NULL
145 };
146 EXPORT_SYMBOL(debug_sprintf_view);
147
148 /* used by dump analysis tools to determine version of debug feature */
149 static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
150
151 /* static globals */
152
153 static debug_info_t *debug_area_first;
154 static debug_info_t *debug_area_last;
155 static DEFINE_MUTEX(debug_mutex);
156
157 static int initialized;
158 static int debug_critical;
159
160 static const struct file_operations debug_file_ops = {
161 .owner = THIS_MODULE,
162 .read = debug_output,
163 .write = debug_input,
164 .open = debug_open,
165 .release = debug_close,
166 .llseek = no_llseek,
167 };
168
169 static struct dentry *debug_debugfs_root_entry;
170
171 /* functions */
172
173 /*
174 * debug_areas_alloc
175 * - Debug areas are implemented as a threedimensonal array:
176 * areas[areanumber][pagenumber][pageoffset]
177 */
178
179 static debug_entry_t ***debug_areas_alloc(int pages_per_area, int nr_areas)
180 {
181 debug_entry_t ***areas;
182 int i, j;
183
184 areas = kmalloc_array(nr_areas, sizeof(debug_entry_t **), GFP_KERNEL);
185 if (!areas)
186 goto fail_malloc_areas;
187 for (i = 0; i < nr_areas; i++) {
188 /* GFP_NOWARN to avoid user triggerable WARN, we handle fails */
189 areas[i] = kmalloc_array(pages_per_area,
190 sizeof(debug_entry_t *),
191 GFP_KERNEL | __GFP_NOWARN);
192 if (!areas[i])
193 goto fail_malloc_areas2;
194 for (j = 0; j < pages_per_area; j++) {
195 areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
196 if (!areas[i][j]) {
197 for (j--; j >= 0 ; j--)
198 kfree(areas[i][j]);
199 kfree(areas[i]);
200 goto fail_malloc_areas2;
201 }
202 }
203 }
204 return areas;
205
206 fail_malloc_areas2:
207 for (i--; i >= 0; i--) {
208 for (j = 0; j < pages_per_area; j++)
209 kfree(areas[i][j]);
210 kfree(areas[i]);
211 }
212 kfree(areas);
213 fail_malloc_areas:
214 return NULL;
215 }
216
217 /*
218 * debug_info_alloc
219 * - alloc new debug-info
220 */
221 static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,
222 int nr_areas, int buf_size, int level,
223 int mode)
224 {
225 debug_info_t *rc;
226
227 /* alloc everything */
228 rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
229 if (!rc)
230 goto fail_malloc_rc;
231 rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
232 if (!rc->active_entries)
233 goto fail_malloc_active_entries;
234 rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
235 if (!rc->active_pages)
236 goto fail_malloc_active_pages;
237 if ((mode == ALL_AREAS) && (pages_per_area != 0)) {
238 rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
239 if (!rc->areas)
240 goto fail_malloc_areas;
241 } else {
242 rc->areas = NULL;
243 }
244
245 /* initialize members */
246 spin_lock_init(&rc->lock);
247 rc->pages_per_area = pages_per_area;
248 rc->nr_areas = nr_areas;
249 rc->active_area = 0;
250 rc->level = level;
251 rc->buf_size = buf_size;
252 rc->entry_size = sizeof(debug_entry_t) + buf_size;
253 strscpy(rc->name, name, sizeof(rc->name));
254 memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
255 memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
256 refcount_set(&(rc->ref_count), 0);
257
258 return rc;
259
260 fail_malloc_areas:
261 kfree(rc->active_pages);
262 fail_malloc_active_pages:
263 kfree(rc->active_entries);
264 fail_malloc_active_entries:
265 kfree(rc);
266 fail_malloc_rc:
267 return NULL;
268 }
269
270 /*
271 * debug_areas_free
272 * - free all debug areas
273 */
274 static void debug_areas_free(debug_info_t *db_info)
275 {
276 int i, j;
277
278 if (!db_info->areas)
279 return;
280 for (i = 0; i < db_info->nr_areas; i++) {
281 for (j = 0; j < db_info->pages_per_area; j++)
282 kfree(db_info->areas[i][j]);
283 kfree(db_info->areas[i]);
284 }
285 kfree(db_info->areas);
286 db_info->areas = NULL;
287 }
288
289 /*
290 * debug_info_free
291 * - free memory debug-info
292 */
293 static void debug_info_free(debug_info_t *db_info)
294 {
295 debug_areas_free(db_info);
296 kfree(db_info->active_entries);
297 kfree(db_info->active_pages);
298 kfree(db_info);
299 }
300
301 /*
302 * debug_info_create
303 * - create new debug-info
304 */
305
306 static debug_info_t *debug_info_create(const char *name, int pages_per_area,
307 int nr_areas, int buf_size, umode_t mode)
308 {
309 debug_info_t *rc;
310
311 rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
312 DEBUG_DEFAULT_LEVEL, ALL_AREAS);
313 if (!rc)
314 goto out;
315
316 rc->mode = mode & ~S_IFMT;
317 refcount_set(&rc->ref_count, 1);
318 out:
319 return rc;
320 }
321
322 /*
323 * debug_info_copy
324 * - copy debug-info
325 */
326 static debug_info_t *debug_info_copy(debug_info_t *in, int mode)
327 {
328 unsigned long flags;
329 debug_info_t *rc;
330 int i, j;
331
332 /* get a consistent copy of the debug areas */
333 do {
334 rc = debug_info_alloc(in->name, in->pages_per_area,
335 in->nr_areas, in->buf_size, in->level, mode);
336 spin_lock_irqsave(&in->lock, flags);
337 if (!rc)
338 goto out;
339 /* has something changed in the meantime ? */
340 if ((rc->pages_per_area == in->pages_per_area) &&
341 (rc->nr_areas == in->nr_areas)) {
342 break;
343 }
344 spin_unlock_irqrestore(&in->lock, flags);
345 debug_info_free(rc);
346 } while (1);
347
348 if (mode == NO_AREAS)
349 goto out;
350
351 for (i = 0; i < in->nr_areas; i++) {
352 for (j = 0; j < in->pages_per_area; j++)
353 memcpy(rc->areas[i][j], in->areas[i][j], PAGE_SIZE);
354 }
355 out:
356 spin_unlock_irqrestore(&in->lock, flags);
357 return rc;
358 }
359
360 /*
361 * debug_info_get
362 * - increments reference count for debug-info
363 */
364 static void debug_info_get(debug_info_t *db_info)
365 {
366 if (db_info)
367 refcount_inc(&db_info->ref_count);
368 }
369
370 /*
371 * debug_info_put:
372 * - decreases reference count for debug-info and frees it if necessary
373 */
374 static void debug_info_put(debug_info_t *db_info)
375 {
376 if (!db_info)
377 return;
378 if (refcount_dec_and_test(&db_info->ref_count))
379 debug_info_free(db_info);
380 }
381
382 /*
383 * debug_format_entry:
384 * - format one debug entry and return size of formated data
385 */
386 static int debug_format_entry(file_private_info_t *p_info)
387 {
388 debug_info_t *id_snap = p_info->debug_info_snap;
389 struct debug_view *view = p_info->view;
390 debug_entry_t *act_entry;
391 size_t len = 0;
392
393 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
394 /* print prolog */
395 if (view->prolog_proc)
396 len += view->prolog_proc(id_snap, view, p_info->temp_buf);
397 goto out;
398 }
399 if (!id_snap->areas) /* this is true, if we have a prolog only view */
400 goto out; /* or if 'pages_per_area' is 0 */
401 act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
402 [p_info->act_page] + p_info->act_entry);
403
404 if (act_entry->clock == 0LL)
405 goto out; /* empty entry */
406 if (view->header_proc)
407 len += view->header_proc(id_snap, view, p_info->act_area,
408 act_entry, p_info->temp_buf + len);
409 if (view->format_proc)
410 len += view->format_proc(id_snap, view, p_info->temp_buf + len,
411 DEBUG_DATA(act_entry));
412 out:
413 return len;
414 }
415
416 /*
417 * debug_next_entry:
418 * - goto next entry in p_info
419 */
420 static inline int debug_next_entry(file_private_info_t *p_info)
421 {
422 debug_info_t *id;
423
424 id = p_info->debug_info_snap;
425 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
426 p_info->act_entry = 0;
427 p_info->act_page = 0;
428 goto out;
429 }
430 if (!id->areas)
431 return 1;
432 p_info->act_entry += id->entry_size;
433 /* switch to next page, if we reached the end of the page */
434 if (p_info->act_entry > (PAGE_SIZE - id->entry_size)) {
435 /* next page */
436 p_info->act_entry = 0;
437 p_info->act_page += 1;
438 if ((p_info->act_page % id->pages_per_area) == 0) {
439 /* next area */
440 p_info->act_area++;
441 p_info->act_page = 0;
442 }
443 if (p_info->act_area >= id->nr_areas)
444 return 1;
445 }
446 out:
447 return 0;
448 }
449
450 /*
451 * debug_output:
452 * - called for user read()
453 * - copies formated debug entries to the user buffer
454 */
455 static ssize_t debug_output(struct file *file, /* file descriptor */
456 char __user *user_buf, /* user buffer */
457 size_t len, /* length of buffer */
458 loff_t *offset) /* offset in the file */
459 {
460 size_t count = 0;
461 size_t entry_offset;
462 file_private_info_t *p_info;
463
464 p_info = (file_private_info_t *) file->private_data;
465 if (*offset != p_info->offset)
466 return -EPIPE;
467 if (p_info->act_area >= p_info->debug_info_snap->nr_areas)
468 return 0;
469 entry_offset = p_info->act_entry_offset;
470 while (count < len) {
471 int formatted_line_residue;
472 int formatted_line_size;
473 int user_buf_residue;
474 size_t copy_size;
475
476 formatted_line_size = debug_format_entry(p_info);
477 formatted_line_residue = formatted_line_size - entry_offset;
478 user_buf_residue = len-count;
479 copy_size = min(user_buf_residue, formatted_line_residue);
480 if (copy_size) {
481 if (copy_to_user(user_buf + count, p_info->temp_buf
482 + entry_offset, copy_size))
483 return -EFAULT;
484 count += copy_size;
485 entry_offset += copy_size;
486 }
487 if (copy_size == formatted_line_residue) {
488 entry_offset = 0;
489 if (debug_next_entry(p_info))
490 goto out;
491 }
492 }
493 out:
494 p_info->offset = *offset + count;
495 p_info->act_entry_offset = entry_offset;
496 *offset = p_info->offset;
497 return count;
498 }
499
500 /*
501 * debug_input:
502 * - called for user write()
503 * - calls input function of view
504 */
505 static ssize_t debug_input(struct file *file, const char __user *user_buf,
506 size_t length, loff_t *offset)
507 {
508 file_private_info_t *p_info;
509 int rc = 0;
510
511 mutex_lock(&debug_mutex);
512 p_info = ((file_private_info_t *) file->private_data);
513 if (p_info->view->input_proc) {
514 rc = p_info->view->input_proc(p_info->debug_info_org,
515 p_info->view, file, user_buf,
516 length, offset);
517 } else {
518 rc = -EPERM;
519 }
520 mutex_unlock(&debug_mutex);
521 return rc; /* number of input characters */
522 }
523
524 /*
525 * debug_open:
526 * - called for user open()
527 * - copies formated output to private_data area of the file
528 * handle
529 */
530 static int debug_open(struct inode *inode, struct file *file)
531 {
532 debug_info_t *debug_info, *debug_info_snapshot;
533 file_private_info_t *p_info;
534 int i, rc = 0;
535
536 mutex_lock(&debug_mutex);
537 debug_info = file_inode(file)->i_private;
538 /* find debug view */
539 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
540 if (!debug_info->views[i])
541 continue;
542 else if (debug_info->debugfs_entries[i] == file->f_path.dentry)
543 goto found; /* found view ! */
544 }
545 /* no entry found */
546 rc = -EINVAL;
547 goto out;
548
549 found:
550
551 /* Make snapshot of current debug areas to get it consistent. */
552 /* To copy all the areas is only needed, if we have a view which */
553 /* formats the debug areas. */
554
555 if (!debug_info->views[i]->format_proc && !debug_info->views[i]->header_proc)
556 debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
557 else
558 debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
559
560 if (!debug_info_snapshot) {
561 rc = -ENOMEM;
562 goto out;
563 }
564 p_info = kmalloc(sizeof(file_private_info_t), GFP_KERNEL);
565 if (!p_info) {
566 debug_info_free(debug_info_snapshot);
567 rc = -ENOMEM;
568 goto out;
569 }
570 p_info->offset = 0;
571 p_info->debug_info_snap = debug_info_snapshot;
572 p_info->debug_info_org = debug_info;
573 p_info->view = debug_info->views[i];
574 p_info->act_area = 0;
575 p_info->act_page = 0;
576 p_info->act_entry = DEBUG_PROLOG_ENTRY;
577 p_info->act_entry_offset = 0;
578 file->private_data = p_info;
579 debug_info_get(debug_info);
580 nonseekable_open(inode, file);
581 out:
582 mutex_unlock(&debug_mutex);
583 return rc;
584 }
585
586 /*
587 * debug_close:
588 * - called for user close()
589 * - deletes private_data area of the file handle
590 */
591 static int debug_close(struct inode *inode, struct file *file)
592 {
593 file_private_info_t *p_info;
594
595 p_info = (file_private_info_t *) file->private_data;
596 if (p_info->debug_info_snap)
597 debug_info_free(p_info->debug_info_snap);
598 debug_info_put(p_info->debug_info_org);
599 kfree(file->private_data);
600 return 0; /* success */
601 }
602
603 /* Create debugfs entries and add to internal list. */
604 static void _debug_register(debug_info_t *id)
605 {
606 /* create root directory */
607 id->debugfs_root_entry = debugfs_create_dir(id->name,
608 debug_debugfs_root_entry);
609
610 /* append new element to linked list */
611 if (!debug_area_first) {
612 /* first element in list */
613 debug_area_first = id;
614 id->prev = NULL;
615 } else {
616 /* append element to end of list */
617 debug_area_last->next = id;
618 id->prev = debug_area_last;
619 }
620 debug_area_last = id;
621 id->next = NULL;
622
623 debug_register_view(id, &debug_level_view);
624 debug_register_view(id, &debug_flush_view);
625 debug_register_view(id, &debug_pages_view);
626 }
627
628 /**
629 * debug_register_mode() - creates and initializes debug area.
630 *
631 * @name: Name of debug log (e.g. used for debugfs entry)
632 * @pages_per_area: Number of pages, which will be allocated per area
633 * @nr_areas: Number of debug areas
634 * @buf_size: Size of data area in each debug entry
635 * @mode: File mode for debugfs files. E.g. S_IRWXUGO
636 * @uid: User ID for debugfs files. Currently only 0 is supported.
637 * @gid: Group ID for debugfs files. Currently only 0 is supported.
638 *
639 * Return:
640 * - Handle for generated debug area
641 * - %NULL if register failed
642 *
643 * Allocates memory for a debug log.
644 * Must not be called within an interrupt handler.
645 */
646 debug_info_t *debug_register_mode(const char *name, int pages_per_area,
647 int nr_areas, int buf_size, umode_t mode,
648 uid_t uid, gid_t gid)
649 {
650 debug_info_t *rc = NULL;
651
652 /* Since debugfs currently does not support uid/gid other than root, */
653 /* we do not allow gid/uid != 0 until we get support for that. */
654 if ((uid != 0) || (gid != 0))
655 pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
656 BUG_ON(!initialized);
657
658 /* create new debug_info */
659 rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
660 if (rc) {
661 mutex_lock(&debug_mutex);
662 _debug_register(rc);
663 mutex_unlock(&debug_mutex);
664 } else {
665 pr_err("Registering debug feature %s failed\n", name);
666 }
667 return rc;
668 }
669 EXPORT_SYMBOL(debug_register_mode);
670
671 /**
672 * debug_register() - creates and initializes debug area with default file mode.
673 *
674 * @name: Name of debug log (e.g. used for debugfs entry)
675 * @pages_per_area: Number of pages, which will be allocated per area
676 * @nr_areas: Number of debug areas
677 * @buf_size: Size of data area in each debug entry
678 *
679 * Return:
680 * - Handle for generated debug area
681 * - %NULL if register failed
682 *
683 * Allocates memory for a debug log.
684 * The debugfs file mode access permissions are read and write for user.
685 * Must not be called within an interrupt handler.
686 */
687 debug_info_t *debug_register(const char *name, int pages_per_area,
688 int nr_areas, int buf_size)
689 {
690 return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
691 S_IRUSR | S_IWUSR, 0, 0);
692 }
693 EXPORT_SYMBOL(debug_register);
694
695 /**
696 * debug_register_static() - registers a static debug area
697 *
698 * @id: Handle for static debug area
699 * @pages_per_area: Number of pages per area
700 * @nr_areas: Number of debug areas
701 *
702 * Register debug_info_t defined using DEFINE_STATIC_DEBUG_INFO.
703 *
704 * Note: This function is called automatically via an initcall generated by
705 * DEFINE_STATIC_DEBUG_INFO.
706 */
707 void debug_register_static(debug_info_t *id, int pages_per_area, int nr_areas)
708 {
709 unsigned long flags;
710 debug_info_t *copy;
711
712 if (!initialized) {
713 pr_err("Tried to register debug feature %s too early\n",
714 id->name);
715 return;
716 }
717
718 copy = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
719 id->level, ALL_AREAS);
720 if (!copy) {
721 pr_err("Registering debug feature %s failed\n", id->name);
722
723 /* Clear pointers to prevent tracing into released initdata. */
724 spin_lock_irqsave(&id->lock, flags);
725 id->areas = NULL;
726 id->active_pages = NULL;
727 id->active_entries = NULL;
728 spin_unlock_irqrestore(&id->lock, flags);
729
730 return;
731 }
732
733 /* Replace static trace area with dynamic copy. */
734 spin_lock_irqsave(&id->lock, flags);
735 debug_events_append(copy, id);
736 debug_areas_swap(id, copy);
737 spin_unlock_irqrestore(&id->lock, flags);
738
739 /* Clear pointers to initdata and discard copy. */
740 copy->areas = NULL;
741 copy->active_pages = NULL;
742 copy->active_entries = NULL;
743 debug_info_free(copy);
744
745 mutex_lock(&debug_mutex);
746 _debug_register(id);
747 mutex_unlock(&debug_mutex);
748 }
749
750 /* Remove debugfs entries and remove from internal list. */
751 static void _debug_unregister(debug_info_t *id)
752 {
753 int i;
754
755 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
756 if (!id->views[i])
757 continue;
758 debugfs_remove(id->debugfs_entries[i]);
759 }
760 debugfs_remove(id->debugfs_root_entry);
761 if (id == debug_area_first)
762 debug_area_first = id->next;
763 if (id == debug_area_last)
764 debug_area_last = id->prev;
765 if (id->prev)
766 id->prev->next = id->next;
767 if (id->next)
768 id->next->prev = id->prev;
769 }
770
771 /**
772 * debug_unregister() - give back debug area.
773 *
774 * @id: handle for debug log
775 *
776 * Return:
777 * none
778 */
779 void debug_unregister(debug_info_t *id)
780 {
781 if (!id)
782 return;
783 mutex_lock(&debug_mutex);
784 _debug_unregister(id);
785 mutex_unlock(&debug_mutex);
786
787 debug_info_put(id);
788 }
789 EXPORT_SYMBOL(debug_unregister);
790
791 /*
792 * debug_set_size:
793 * - set area size (number of pages) and number of areas
794 */
795 static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
796 {
797 debug_info_t *new_id;
798 unsigned long flags;
799
800 if (!id || (nr_areas <= 0) || (pages_per_area < 0))
801 return -EINVAL;
802
803 new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
804 id->level, ALL_AREAS);
805 if (!new_id) {
806 pr_info("Allocating memory for %i pages failed\n",
807 pages_per_area);
808 return -ENOMEM;
809 }
810
811 spin_lock_irqsave(&id->lock, flags);
812 debug_events_append(new_id, id);
813 debug_areas_swap(new_id, id);
814 debug_info_free(new_id);
815 spin_unlock_irqrestore(&id->lock, flags);
816 pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
817
818 return 0;
819 }
820
821 /**
822 * debug_set_level() - Sets new actual debug level if new_level is valid.
823 *
824 * @id: handle for debug log
825 * @new_level: new debug level
826 *
827 * Return:
828 * none
829 */
830 void debug_set_level(debug_info_t *id, int new_level)
831 {
832 unsigned long flags;
833
834 if (!id)
835 return;
836
837 if (new_level == DEBUG_OFF_LEVEL) {
838 pr_info("%s: switched off\n", id->name);
839 } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
840 pr_info("%s: level %i is out of range (%i - %i)\n",
841 id->name, new_level, 0, DEBUG_MAX_LEVEL);
842 return;
843 }
844
845 spin_lock_irqsave(&id->lock, flags);
846 id->level = new_level;
847 spin_unlock_irqrestore(&id->lock, flags);
848 }
849 EXPORT_SYMBOL(debug_set_level);
850
851 /*
852 * proceed_active_entry:
853 * - set active entry to next in the ring buffer
854 */
855 static inline void proceed_active_entry(debug_info_t *id)
856 {
857 if ((id->active_entries[id->active_area] += id->entry_size)
858 > (PAGE_SIZE - id->entry_size)) {
859 id->active_entries[id->active_area] = 0;
860 id->active_pages[id->active_area] =
861 (id->active_pages[id->active_area] + 1) %
862 id->pages_per_area;
863 }
864 }
865
866 /*
867 * proceed_active_area:
868 * - set active area to next in the ring buffer
869 */
870 static inline void proceed_active_area(debug_info_t *id)
871 {
872 id->active_area++;
873 id->active_area = id->active_area % id->nr_areas;
874 }
875
876 /*
877 * get_active_entry:
878 */
879 static inline debug_entry_t *get_active_entry(debug_info_t *id)
880 {
881 return (debug_entry_t *) (((char *) id->areas[id->active_area]
882 [id->active_pages[id->active_area]]) +
883 id->active_entries[id->active_area]);
884 }
885
886 /* Swap debug areas of a and b. */
887 static void debug_areas_swap(debug_info_t *a, debug_info_t *b)
888 {
889 swap(a->nr_areas, b->nr_areas);
890 swap(a->pages_per_area, b->pages_per_area);
891 swap(a->areas, b->areas);
892 swap(a->active_area, b->active_area);
893 swap(a->active_pages, b->active_pages);
894 swap(a->active_entries, b->active_entries);
895 }
896
897 /* Append all debug events in active area from source to destination log. */
898 static void debug_events_append(debug_info_t *dest, debug_info_t *src)
899 {
900 debug_entry_t *from, *to, *last;
901
902 if (!src->areas || !dest->areas)
903 return;
904
905 /* Loop over all entries in src, starting with oldest. */
906 from = get_active_entry(src);
907 last = from;
908 do {
909 if (from->clock != 0LL) {
910 to = get_active_entry(dest);
911 memset(to, 0, dest->entry_size);
912 memcpy(to, from, min(src->entry_size,
913 dest->entry_size));
914 proceed_active_entry(dest);
915 }
916
917 proceed_active_entry(src);
918 from = get_active_entry(src);
919 } while (from != last);
920 }
921
922 /*
923 * debug_finish_entry:
924 * - set timestamp, caller address, cpu number etc.
925 */
926
927 static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
928 int level, int exception)
929 {
930 unsigned long timestamp;
931 union tod_clock clk;
932
933 store_tod_clock_ext(&clk);
934 timestamp = clk.us;
935 timestamp -= TOD_UNIX_EPOCH >> 12;
936 active->clock = timestamp;
937 active->cpu = smp_processor_id();
938 active->caller = __builtin_return_address(0);
939 active->exception = exception;
940 active->level = level;
941 proceed_active_entry(id);
942 if (exception)
943 proceed_active_area(id);
944 }
945
946 static int debug_stoppable = 1;
947 static int debug_active = 1;
948
949 #define CTL_S390DBF_STOPPABLE 5678
950 #define CTL_S390DBF_ACTIVE 5679
951
952 /*
953 * proc handler for the running debug_active sysctl
954 * always allow read, allow write only if debug_stoppable is set or
955 * if debug_active is already off
956 */
957 static int s390dbf_procactive(const struct ctl_table *table, int write,
958 void *buffer, size_t *lenp, loff_t *ppos)
959 {
960 if (!write || debug_stoppable || !debug_active)
961 return proc_dointvec(table, write, buffer, lenp, ppos);
962 else
963 return 0;
964 }
965
966 static struct ctl_table s390dbf_table[] = {
967 {
968 .procname = "debug_stoppable",
969 .data = &debug_stoppable,
970 .maxlen = sizeof(int),
971 .mode = S_IRUGO | S_IWUSR,
972 .proc_handler = proc_dointvec,
973 },
974 {
975 .procname = "debug_active",
976 .data = &debug_active,
977 .maxlen = sizeof(int),
978 .mode = S_IRUGO | S_IWUSR,
979 .proc_handler = s390dbf_procactive,
980 },
981 };
982
983 static struct ctl_table_header *s390dbf_sysctl_header;
984
985 /**
986 * debug_stop_all() - stops the debug feature if stopping is allowed.
987 *
988 * Return:
989 * - none
990 *
991 * Currently used in case of a kernel oops.
992 */
993 void debug_stop_all(void)
994 {
995 if (debug_stoppable)
996 debug_active = 0;
997 }
998 EXPORT_SYMBOL(debug_stop_all);
999
1000 /**
1001 * debug_set_critical() - event/exception functions try lock instead of spin.
1002 *
1003 * Return:
1004 * - none
1005 *
1006 * Currently used in case of stopping all CPUs but the current one.
1007 * Once in this state, functions to write a debug entry for an
1008 * event or exception no longer spin on the debug area lock,
1009 * but only try to get it and fail if they do not get the lock.
1010 */
1011 void debug_set_critical(void)
1012 {
1013 debug_critical = 1;
1014 }
1015
1016 /*
1017 * debug_event_common:
1018 * - write debug entry with given size
1019 */
1020 debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
1021 int len)
1022 {
1023 debug_entry_t *active;
1024 unsigned long flags;
1025
1026 if (!debug_active || !id->areas)
1027 return NULL;
1028 if (debug_critical) {
1029 if (!spin_trylock_irqsave(&id->lock, flags))
1030 return NULL;
1031 } else {
1032 spin_lock_irqsave(&id->lock, flags);
1033 }
1034 do {
1035 active = get_active_entry(id);
1036 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1037 if (len < id->buf_size)
1038 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1039 debug_finish_entry(id, active, level, 0);
1040 len -= id->buf_size;
1041 buf += id->buf_size;
1042 } while (len > 0);
1043
1044 spin_unlock_irqrestore(&id->lock, flags);
1045 return active;
1046 }
1047 EXPORT_SYMBOL(debug_event_common);
1048
1049 /*
1050 * debug_exception_common:
1051 * - write debug entry with given size and switch to next debug area
1052 */
1053 debug_entry_t *debug_exception_common(debug_info_t *id, int level,
1054 const void *buf, int len)
1055 {
1056 debug_entry_t *active;
1057 unsigned long flags;
1058
1059 if (!debug_active || !id->areas)
1060 return NULL;
1061 if (debug_critical) {
1062 if (!spin_trylock_irqsave(&id->lock, flags))
1063 return NULL;
1064 } else {
1065 spin_lock_irqsave(&id->lock, flags);
1066 }
1067 do {
1068 active = get_active_entry(id);
1069 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1070 if (len < id->buf_size)
1071 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1072 debug_finish_entry(id, active, level, len <= id->buf_size);
1073 len -= id->buf_size;
1074 buf += id->buf_size;
1075 } while (len > 0);
1076
1077 spin_unlock_irqrestore(&id->lock, flags);
1078 return active;
1079 }
1080 EXPORT_SYMBOL(debug_exception_common);
1081
1082 /*
1083 * counts arguments in format string for sprintf view
1084 */
1085 static inline int debug_count_numargs(char *string)
1086 {
1087 int numargs = 0;
1088
1089 while (*string) {
1090 if (*string++ == '%')
1091 numargs++;
1092 }
1093 return numargs;
1094 }
1095
1096 /*
1097 * debug_sprintf_event:
1098 */
1099 debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
1100 {
1101 debug_sprintf_entry_t *curr_event;
1102 debug_entry_t *active;
1103 unsigned long flags;
1104 int numargs, idx;
1105 va_list ap;
1106
1107 if (!debug_active || !id->areas)
1108 return NULL;
1109 numargs = debug_count_numargs(string);
1110
1111 if (debug_critical) {
1112 if (!spin_trylock_irqsave(&id->lock, flags))
1113 return NULL;
1114 } else {
1115 spin_lock_irqsave(&id->lock, flags);
1116 }
1117 active = get_active_entry(id);
1118 curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
1119 va_start(ap, string);
1120 curr_event->string = string;
1121 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1122 curr_event->args[idx] = va_arg(ap, long);
1123 va_end(ap);
1124 debug_finish_entry(id, active, level, 0);
1125 spin_unlock_irqrestore(&id->lock, flags);
1126
1127 return active;
1128 }
1129 EXPORT_SYMBOL(__debug_sprintf_event);
1130
1131 /*
1132 * debug_sprintf_exception:
1133 */
1134 debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1135 {
1136 debug_sprintf_entry_t *curr_event;
1137 debug_entry_t *active;
1138 unsigned long flags;
1139 int numargs, idx;
1140 va_list ap;
1141
1142 if (!debug_active || !id->areas)
1143 return NULL;
1144
1145 numargs = debug_count_numargs(string);
1146
1147 if (debug_critical) {
1148 if (!spin_trylock_irqsave(&id->lock, flags))
1149 return NULL;
1150 } else {
1151 spin_lock_irqsave(&id->lock, flags);
1152 }
1153 active = get_active_entry(id);
1154 curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
1155 va_start(ap, string);
1156 curr_event->string = string;
1157 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1158 curr_event->args[idx] = va_arg(ap, long);
1159 va_end(ap);
1160 debug_finish_entry(id, active, level, 1);
1161 spin_unlock_irqrestore(&id->lock, flags);
1162
1163 return active;
1164 }
1165 EXPORT_SYMBOL(__debug_sprintf_exception);
1166
1167 /**
1168 * debug_register_view() - registers new debug view and creates debugfs
1169 * dir entry
1170 *
1171 * @id: handle for debug log
1172 * @view: pointer to debug view struct
1173 *
1174 * Return:
1175 * - 0 : ok
1176 * - < 0: Error
1177 */
1178 int debug_register_view(debug_info_t *id, struct debug_view *view)
1179 {
1180 unsigned long flags;
1181 struct dentry *pde;
1182 umode_t mode;
1183 int rc = 0;
1184 int i;
1185
1186 if (!id)
1187 goto out;
1188 mode = (id->mode | S_IFREG) & ~S_IXUGO;
1189 if (!(view->prolog_proc || view->format_proc || view->header_proc))
1190 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1191 if (!view->input_proc)
1192 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1193 pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1194 id, &debug_file_ops);
1195 spin_lock_irqsave(&id->lock, flags);
1196 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1197 if (!id->views[i])
1198 break;
1199 }
1200 if (i == DEBUG_MAX_VIEWS) {
1201 rc = -1;
1202 } else {
1203 id->views[i] = view;
1204 id->debugfs_entries[i] = pde;
1205 }
1206 spin_unlock_irqrestore(&id->lock, flags);
1207 if (rc) {
1208 pr_err("Registering view %s/%s would exceed the maximum "
1209 "number of views %i\n", id->name, view->name, i);
1210 debugfs_remove(pde);
1211 }
1212 out:
1213 return rc;
1214 }
1215 EXPORT_SYMBOL(debug_register_view);
1216
1217 /**
1218 * debug_unregister_view() - unregisters debug view and removes debugfs
1219 * dir entry
1220 *
1221 * @id: handle for debug log
1222 * @view: pointer to debug view struct
1223 *
1224 * Return:
1225 * - 0 : ok
1226 * - < 0: Error
1227 */
1228 int debug_unregister_view(debug_info_t *id, struct debug_view *view)
1229 {
1230 struct dentry *dentry = NULL;
1231 unsigned long flags;
1232 int i, rc = 0;
1233
1234 if (!id)
1235 goto out;
1236 spin_lock_irqsave(&id->lock, flags);
1237 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1238 if (id->views[i] == view)
1239 break;
1240 }
1241 if (i == DEBUG_MAX_VIEWS) {
1242 rc = -1;
1243 } else {
1244 dentry = id->debugfs_entries[i];
1245 id->views[i] = NULL;
1246 id->debugfs_entries[i] = NULL;
1247 }
1248 spin_unlock_irqrestore(&id->lock, flags);
1249 debugfs_remove(dentry);
1250 out:
1251 return rc;
1252 }
1253 EXPORT_SYMBOL(debug_unregister_view);
1254
1255 static inline char *debug_get_user_string(const char __user *user_buf,
1256 size_t user_len)
1257 {
1258 char *buffer;
1259
1260 buffer = kmalloc(user_len + 1, GFP_KERNEL);
1261 if (!buffer)
1262 return ERR_PTR(-ENOMEM);
1263 if (copy_from_user(buffer, user_buf, user_len) != 0) {
1264 kfree(buffer);
1265 return ERR_PTR(-EFAULT);
1266 }
1267 /* got the string, now strip linefeed. */
1268 if (buffer[user_len - 1] == '\n')
1269 buffer[user_len - 1] = 0;
1270 else
1271 buffer[user_len] = 0;
1272 return buffer;
1273 }
1274
1275 static inline int debug_get_uint(char *buf)
1276 {
1277 int rc;
1278
1279 buf = skip_spaces(buf);
1280 rc = simple_strtoul(buf, &buf, 10);
1281 if (*buf)
1282 rc = -EINVAL;
1283 return rc;
1284 }
1285
1286 /*
1287 * functions for debug-views
1288 ***********************************
1289 */
1290
1291 /*
1292 * prints out actual debug level
1293 */
1294
1295 static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
1296 char *out_buf)
1297 {
1298 return sprintf(out_buf, "%i\n", id->pages_per_area);
1299 }
1300
1301 /*
1302 * reads new size (number of pages per debug area)
1303 */
1304
1305 static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
1306 struct file *file, const char __user *user_buf,
1307 size_t user_len, loff_t *offset)
1308 {
1309 int rc, new_pages;
1310 char *str;
1311
1312 if (user_len > 0x10000)
1313 user_len = 0x10000;
1314 if (*offset != 0) {
1315 rc = -EPIPE;
1316 goto out;
1317 }
1318 str = debug_get_user_string(user_buf, user_len);
1319 if (IS_ERR(str)) {
1320 rc = PTR_ERR(str);
1321 goto out;
1322 }
1323 new_pages = debug_get_uint(str);
1324 if (new_pages < 0) {
1325 rc = -EINVAL;
1326 goto free_str;
1327 }
1328 rc = debug_set_size(id, id->nr_areas, new_pages);
1329 if (rc != 0) {
1330 rc = -EINVAL;
1331 goto free_str;
1332 }
1333 rc = user_len;
1334 free_str:
1335 kfree(str);
1336 out:
1337 *offset += user_len;
1338 return rc; /* number of input characters */
1339 }
1340
1341 /*
1342 * prints out actual debug level
1343 */
1344 static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
1345 char *out_buf)
1346 {
1347 int rc = 0;
1348
1349 if (id->level == DEBUG_OFF_LEVEL)
1350 rc = sprintf(out_buf, "-\n");
1351 else
1352 rc = sprintf(out_buf, "%i\n", id->level);
1353 return rc;
1354 }
1355
1356 /*
1357 * reads new debug level
1358 */
1359 static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
1360 struct file *file, const char __user *user_buf,
1361 size_t user_len, loff_t *offset)
1362 {
1363 int rc, new_level;
1364 char *str;
1365
1366 if (user_len > 0x10000)
1367 user_len = 0x10000;
1368 if (*offset != 0) {
1369 rc = -EPIPE;
1370 goto out;
1371 }
1372 str = debug_get_user_string(user_buf, user_len);
1373 if (IS_ERR(str)) {
1374 rc = PTR_ERR(str);
1375 goto out;
1376 }
1377 if (str[0] == '-') {
1378 debug_set_level(id, DEBUG_OFF_LEVEL);
1379 rc = user_len;
1380 goto free_str;
1381 } else {
1382 new_level = debug_get_uint(str);
1383 }
1384 if (new_level < 0) {
1385 pr_warn("%s is not a valid level for a debug feature\n", str);
1386 rc = -EINVAL;
1387 } else {
1388 debug_set_level(id, new_level);
1389 rc = user_len;
1390 }
1391 free_str:
1392 kfree(str);
1393 out:
1394 *offset += user_len;
1395 return rc; /* number of input characters */
1396 }
1397
1398 /*
1399 * flushes debug areas
1400 */
1401 static void debug_flush(debug_info_t *id, int area)
1402 {
1403 unsigned long flags;
1404 int i, j;
1405
1406 if (!id || !id->areas)
1407 return;
1408 spin_lock_irqsave(&id->lock, flags);
1409 if (area == DEBUG_FLUSH_ALL) {
1410 id->active_area = 0;
1411 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1412 for (i = 0; i < id->nr_areas; i++) {
1413 id->active_pages[i] = 0;
1414 for (j = 0; j < id->pages_per_area; j++)
1415 memset(id->areas[i][j], 0, PAGE_SIZE);
1416 }
1417 } else if (area >= 0 && area < id->nr_areas) {
1418 id->active_entries[area] = 0;
1419 id->active_pages[area] = 0;
1420 for (i = 0; i < id->pages_per_area; i++)
1421 memset(id->areas[area][i], 0, PAGE_SIZE);
1422 }
1423 spin_unlock_irqrestore(&id->lock, flags);
1424 }
1425
1426 /*
1427 * view function: flushes debug areas
1428 */
1429 static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
1430 struct file *file, const char __user *user_buf,
1431 size_t user_len, loff_t *offset)
1432 {
1433 char input_buf[1];
1434 int rc = user_len;
1435
1436 if (user_len > 0x10000)
1437 user_len = 0x10000;
1438 if (*offset != 0) {
1439 rc = -EPIPE;
1440 goto out;
1441 }
1442 if (copy_from_user(input_buf, user_buf, 1)) {
1443 rc = -EFAULT;
1444 goto out;
1445 }
1446 if (input_buf[0] == '-') {
1447 debug_flush(id, DEBUG_FLUSH_ALL);
1448 goto out;
1449 }
1450 if (isdigit(input_buf[0])) {
1451 int area = ((int) input_buf[0] - (int) '');
1452
1453 debug_flush(id, area);
1454 goto out;
1455 }
1456
1457 pr_info("Flushing debug data failed because %c is not a valid "
1458 "area\n", input_buf[0]);
1459
1460 out:
1461 *offset += user_len;
1462 return rc; /* number of input characters */
1463 }
1464
1465 /*
1466 * prints debug data in hex/ascii format
1467 */
1468 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
1469 char *out_buf, const char *in_buf)
1470 {
1471 int i, rc = 0;
1472
1473 for (i = 0; i < id->buf_size; i++)
1474 rc += sprintf(out_buf + rc, "%02x ", ((unsigned char *) in_buf)[i]);
1475 rc += sprintf(out_buf + rc, "| ");
1476 for (i = 0; i < id->buf_size; i++) {
1477 unsigned char c = in_buf[i];
1478
1479 if (isascii(c) && isprint(c))
1480 rc += sprintf(out_buf + rc, "%c", c);
1481 else
1482 rc += sprintf(out_buf + rc, ".");
1483 }
1484 rc += sprintf(out_buf + rc, "\n");
1485 return rc;
1486 }
1487
1488 /*
1489 * prints header for debug entry
1490 */
1491 int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
1492 int area, debug_entry_t *entry, char *out_buf)
1493 {
1494 unsigned long sec, usec;
1495 unsigned long caller;
1496 unsigned int level;
1497 char *except_str;
1498 int rc = 0;
1499
1500 level = entry->level;
1501 sec = entry->clock;
1502 usec = do_div(sec, USEC_PER_SEC);
1503
1504 if (entry->exception)
1505 except_str = "*";
1506 else
1507 except_str = "-";
1508 caller = (unsigned long) entry->caller;
1509 rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %04u %px ",
1510 area, sec, usec, level, except_str,
1511 entry->cpu, (void *)caller);
1512 return rc;
1513 }
1514 EXPORT_SYMBOL(debug_dflt_header_fn);
1515
1516 /*
1517 * prints debug data sprintf-formated:
1518 * debug_sprinf_event/exception calls must be used together with this view
1519 */
1520
1521 #define DEBUG_SPRINTF_MAX_ARGS 10
1522
1523 static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
1524 char *out_buf, const char *inbuf)
1525 {
1526 debug_sprintf_entry_t *curr_event = (debug_sprintf_entry_t *)inbuf;
1527 int num_longs, num_used_args = 0, i, rc = 0;
1528 int index[DEBUG_SPRINTF_MAX_ARGS];
1529
1530 /* count of longs fit into one entry */
1531 num_longs = id->buf_size / sizeof(long);
1532
1533 if (num_longs < 1)
1534 goto out; /* bufsize of entry too small */
1535 if (num_longs == 1) {
1536 /* no args, we use only the string */
1537 strcpy(out_buf, curr_event->string);
1538 rc = strlen(curr_event->string);
1539 goto out;
1540 }
1541
1542 /* number of arguments used for sprintf (without the format string) */
1543 num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1544
1545 memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1546
1547 for (i = 0; i < num_used_args; i++)
1548 index[i] = i;
1549
1550 rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1551 curr_event->args[index[1]], curr_event->args[index[2]],
1552 curr_event->args[index[3]], curr_event->args[index[4]],
1553 curr_event->args[index[5]], curr_event->args[index[6]],
1554 curr_event->args[index[7]], curr_event->args[index[8]],
1555 curr_event->args[index[9]]);
1556 out:
1557 return rc;
1558 }
1559
1560 /*
1561 * debug_init:
1562 * - is called exactly once to initialize the debug feature
1563 */
1564 static int __init debug_init(void)
1565 {
1566 s390dbf_sysctl_header = register_sysctl("s390dbf", s390dbf_table);
1567 mutex_lock(&debug_mutex);
1568 debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1569 initialized = 1;
1570 mutex_unlock(&debug_mutex);
1571 return 0;
1572 }
1573 postcore_initcall(debug_init);
1574
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