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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
39typedef struct file_private_info {
40 loff_t offset; /* offset of last read in file */
41 int act_area; /* number of last formatted area */
42 int act_page; /* act page in given area */
43 int act_entry; /* last formatted entry (offset */
44 /* relative to beginning of last */
45 /* formatted page) */
46 size_t act_entry_offset; /* up to this offset we copied */
47 /* in last read the last formatted */
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
55typedef 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 prototypes */
67
68static int debug_init(void);
69static ssize_t debug_output(struct file *file, char __user *user_buf,
70 size_t user_len, loff_t *offset);
71static ssize_t debug_input(struct file *file, const char __user *user_buf,
72 size_t user_len, loff_t *offset);
73static int debug_open(struct inode *inode, struct file *file);
74static int debug_close(struct inode *inode, struct file *file);
75static debug_info_t *debug_info_create(const char *name, int pages_per_area,
76 int nr_areas, int buf_size, umode_t mode);
77static void debug_info_get(debug_info_t *);
78static void debug_info_put(debug_info_t *);
79static int debug_prolog_level_fn(debug_info_t *id,
80 struct debug_view *view, char *out_buf,
81 size_t out_buf_size);
82static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
83 struct file *file, const char __user *user_buf,
84 size_t user_buf_size, loff_t *offset);
85static int debug_prolog_pages_fn(debug_info_t *id,
86 struct debug_view *view, char *out_buf,
87 size_t out_buf_size);
88static int debug_input_pages_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);
91static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
92 struct file *file, const char __user *user_buf,
93 size_t user_buf_size, loff_t *offset);
94static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
95 char *out_buf, size_t out_buf_size,
96 const char *in_buf);
97static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
98 char *out_buf, size_t out_buf_size,
99 const char *inbuf);
100static void debug_areas_swap(debug_info_t *a, debug_info_t *b);
101static void debug_events_append(debug_info_t *dest, debug_info_t *src);
102
103/* globals */
104
105struct debug_view debug_hex_ascii_view = {
106 "hex_ascii",
107 NULL,
108 &debug_dflt_header_fn,
109 &debug_hex_ascii_format_fn,
110 NULL,
111 NULL
112};
113EXPORT_SYMBOL(debug_hex_ascii_view);
114
115static struct debug_view debug_level_view = {
116 "level",
117 &debug_prolog_level_fn,
118 NULL,
119 NULL,
120 &debug_input_level_fn,
121 NULL
122};
123
124static struct debug_view debug_pages_view = {
125 "pages",
126 &debug_prolog_pages_fn,
127 NULL,
128 NULL,
129 &debug_input_pages_fn,
130 NULL
131};
132
133static struct debug_view debug_flush_view = {
134 "flush",
135 NULL,
136 NULL,
137 NULL,
138 &debug_input_flush_fn,
139 NULL
140};
141
142struct debug_view debug_sprintf_view = {
143 "sprintf",
144 NULL,
145 &debug_dflt_header_fn,
146 &debug_sprintf_format_fn,
147 NULL,
148 NULL
149};
150EXPORT_SYMBOL(debug_sprintf_view);
151
152/* used by dump analysis tools to determine version of debug feature */
153static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
154
155/* static globals */
156
157static debug_info_t *debug_area_first;
158static debug_info_t *debug_area_last;
159static DEFINE_MUTEX(debug_mutex);
160
161static int initialized;
162static int debug_critical;
163
164static const struct file_operations debug_file_ops = {
165 .owner = THIS_MODULE,
166 .read = debug_output,
167 .write = debug_input,
168 .open = debug_open,
169 .release = debug_close,
170};
171
172static struct dentry *debug_debugfs_root_entry;
173
174/* functions */
175
176/*
177 * debug_areas_alloc
178 * - Debug areas are implemented as a threedimensonal array:
179 * areas[areanumber][pagenumber][pageoffset]
180 */
181
182static debug_entry_t ***debug_areas_alloc(int pages_per_area, int nr_areas)
183{
184 debug_entry_t ***areas;
185 int i, j;
186
187 areas = kmalloc_array(nr_areas, sizeof(debug_entry_t **), GFP_KERNEL);
188 if (!areas)
189 goto fail_malloc_areas;
190 for (i = 0; i < nr_areas; i++) {
191 /* GFP_NOWARN to avoid user triggerable WARN, we handle fails */
192 areas[i] = kmalloc_array(pages_per_area,
193 sizeof(debug_entry_t *),
194 GFP_KERNEL | __GFP_NOWARN);
195 if (!areas[i])
196 goto fail_malloc_areas2;
197 for (j = 0; j < pages_per_area; j++) {
198 areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
199 if (!areas[i][j]) {
200 for (j--; j >= 0 ; j--)
201 kfree(areas[i][j]);
202 kfree(areas[i]);
203 goto fail_malloc_areas2;
204 }
205 }
206 }
207 return areas;
208
209fail_malloc_areas2:
210 for (i--; i >= 0; i--) {
211 for (j = 0; j < pages_per_area; j++)
212 kfree(areas[i][j]);
213 kfree(areas[i]);
214 }
215 kfree(areas);
216fail_malloc_areas:
217 return NULL;
218}
219
220/*
221 * debug_info_alloc
222 * - alloc new debug-info
223 */
224static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,
225 int nr_areas, int buf_size, int level,
226 int mode)
227{
228 debug_info_t *rc;
229
230 /* alloc everything */
231 rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
232 if (!rc)
233 goto fail_malloc_rc;
234 rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
235 if (!rc->active_entries)
236 goto fail_malloc_active_entries;
237 rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
238 if (!rc->active_pages)
239 goto fail_malloc_active_pages;
240 if ((mode == ALL_AREAS) && (pages_per_area != 0)) {
241 rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
242 if (!rc->areas)
243 goto fail_malloc_areas;
244 } else {
245 rc->areas = NULL;
246 }
247
248 /* initialize members */
249 spin_lock_init(&rc->lock);
250 rc->pages_per_area = pages_per_area;
251 rc->nr_areas = nr_areas;
252 rc->active_area = 0;
253 rc->level = level;
254 rc->buf_size = buf_size;
255 rc->entry_size = sizeof(debug_entry_t) + buf_size;
256 strscpy(rc->name, name, sizeof(rc->name));
257 memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
258 memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
259 refcount_set(&(rc->ref_count), 0);
260
261 return rc;
262
263fail_malloc_areas:
264 kfree(rc->active_pages);
265fail_malloc_active_pages:
266 kfree(rc->active_entries);
267fail_malloc_active_entries:
268 kfree(rc);
269fail_malloc_rc:
270 return NULL;
271}
272
273/*
274 * debug_areas_free
275 * - free all debug areas
276 */
277static void debug_areas_free(debug_info_t *db_info)
278{
279 int i, j;
280
281 if (!db_info->areas)
282 return;
283 for (i = 0; i < db_info->nr_areas; i++) {
284 for (j = 0; j < db_info->pages_per_area; j++)
285 kfree(db_info->areas[i][j]);
286 kfree(db_info->areas[i]);
287 }
288 kfree(db_info->areas);
289 db_info->areas = NULL;
290}
291
292/*
293 * debug_info_free
294 * - free memory debug-info
295 */
296static void debug_info_free(debug_info_t *db_info)
297{
298 debug_areas_free(db_info);
299 kfree(db_info->active_entries);
300 kfree(db_info->active_pages);
301 kfree(db_info);
302}
303
304/*
305 * debug_info_create
306 * - create new debug-info
307 */
308
309static debug_info_t *debug_info_create(const char *name, int pages_per_area,
310 int nr_areas, int buf_size, umode_t mode)
311{
312 debug_info_t *rc;
313
314 rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
315 DEBUG_DEFAULT_LEVEL, ALL_AREAS);
316 if (!rc)
317 goto out;
318
319 rc->mode = mode & ~S_IFMT;
320 refcount_set(&rc->ref_count, 1);
321out:
322 return rc;
323}
324
325/*
326 * debug_info_copy
327 * - copy debug-info
328 */
329static debug_info_t *debug_info_copy(debug_info_t *in, int mode)
330{
331 unsigned long flags;
332 debug_info_t *rc;
333 int i, j;
334
335 /* get a consistent copy of the debug areas */
336 do {
337 rc = debug_info_alloc(in->name, in->pages_per_area,
338 in->nr_areas, in->buf_size, in->level, mode);
339 spin_lock_irqsave(&in->lock, flags);
340 if (!rc)
341 goto out;
342 /* has something changed in the meantime ? */
343 if ((rc->pages_per_area == in->pages_per_area) &&
344 (rc->nr_areas == in->nr_areas)) {
345 break;
346 }
347 spin_unlock_irqrestore(&in->lock, flags);
348 debug_info_free(rc);
349 } while (1);
350
351 if (mode == NO_AREAS)
352 goto out;
353
354 for (i = 0; i < in->nr_areas; i++) {
355 for (j = 0; j < in->pages_per_area; j++)
356 memcpy(rc->areas[i][j], in->areas[i][j], PAGE_SIZE);
357 }
358out:
359 spin_unlock_irqrestore(&in->lock, flags);
360 return rc;
361}
362
363/*
364 * debug_info_get
365 * - increments reference count for debug-info
366 */
367static void debug_info_get(debug_info_t *db_info)
368{
369 if (db_info)
370 refcount_inc(&db_info->ref_count);
371}
372
373/*
374 * debug_info_put:
375 * - decreases reference count for debug-info and frees it if necessary
376 */
377static void debug_info_put(debug_info_t *db_info)
378{
379 if (!db_info)
380 return;
381 if (refcount_dec_and_test(&db_info->ref_count))
382 debug_info_free(db_info);
383}
384
385/*
386 * debug_format_entry:
387 * - format one debug entry and return size of formatted data
388 */
389static int debug_format_entry(file_private_info_t *p_info)
390{
391 debug_info_t *id_snap = p_info->debug_info_snap;
392 struct debug_view *view = p_info->view;
393 debug_entry_t *act_entry;
394 size_t len = 0;
395
396 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
397 /* print prolog */
398 if (view->prolog_proc) {
399 len += view->prolog_proc(id_snap, view, p_info->temp_buf,
400 sizeof(p_info->temp_buf));
401 }
402 goto out;
403 }
404 if (!id_snap->areas) /* this is true, if we have a prolog only view */
405 goto out; /* or if 'pages_per_area' is 0 */
406 act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
407 [p_info->act_page] + p_info->act_entry);
408
409 if (act_entry->clock == 0LL)
410 goto out; /* empty entry */
411 if (view->header_proc) {
412 len += view->header_proc(id_snap, view, p_info->act_area,
413 act_entry, p_info->temp_buf + len,
414 sizeof(p_info->temp_buf) - len);
415 }
416 if (view->format_proc) {
417 len += view->format_proc(id_snap, view, p_info->temp_buf + len,
418 sizeof(p_info->temp_buf) - len,
419 DEBUG_DATA(act_entry));
420 }
421out:
422 return len;
423}
424
425/*
426 * debug_next_entry:
427 * - goto next entry in p_info
428 */
429static inline int debug_next_entry(file_private_info_t *p_info)
430{
431 debug_info_t *id;
432
433 id = p_info->debug_info_snap;
434 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
435 p_info->act_entry = 0;
436 p_info->act_page = 0;
437 goto out;
438 }
439 if (!id->areas)
440 return 1;
441 p_info->act_entry += id->entry_size;
442 /* switch to next page, if we reached the end of the page */
443 if (p_info->act_entry > (PAGE_SIZE - id->entry_size)) {
444 /* next page */
445 p_info->act_entry = 0;
446 p_info->act_page += 1;
447 if ((p_info->act_page % id->pages_per_area) == 0) {
448 /* next area */
449 p_info->act_area++;
450 p_info->act_page = 0;
451 }
452 if (p_info->act_area >= id->nr_areas)
453 return 1;
454 }
455out:
456 return 0;
457}
458
459/*
460 * debug_output:
461 * - called for user read()
462 * - copies formatted debug entries to the user buffer
463 */
464static ssize_t debug_output(struct file *file, /* file descriptor */
465 char __user *user_buf, /* user buffer */
466 size_t len, /* length of buffer */
467 loff_t *offset) /* offset in the file */
468{
469 size_t count = 0;
470 size_t entry_offset;
471 file_private_info_t *p_info;
472
473 p_info = (file_private_info_t *) file->private_data;
474 if (*offset != p_info->offset)
475 return -EPIPE;
476 if (p_info->act_area >= p_info->debug_info_snap->nr_areas)
477 return 0;
478 entry_offset = p_info->act_entry_offset;
479 while (count < len) {
480 int formatted_line_residue;
481 int formatted_line_size;
482 int user_buf_residue;
483 size_t copy_size;
484
485 formatted_line_size = debug_format_entry(p_info);
486 formatted_line_residue = formatted_line_size - entry_offset;
487 user_buf_residue = len-count;
488 copy_size = min(user_buf_residue, formatted_line_residue);
489 if (copy_size) {
490 if (copy_to_user(user_buf + count, p_info->temp_buf
491 + entry_offset, copy_size))
492 return -EFAULT;
493 count += copy_size;
494 entry_offset += copy_size;
495 }
496 if (copy_size == formatted_line_residue) {
497 entry_offset = 0;
498 if (debug_next_entry(p_info))
499 goto out;
500 }
501 }
502out:
503 p_info->offset = *offset + count;
504 p_info->act_entry_offset = entry_offset;
505 *offset = p_info->offset;
506 return count;
507}
508
509/*
510 * debug_input:
511 * - called for user write()
512 * - calls input function of view
513 */
514static ssize_t debug_input(struct file *file, const char __user *user_buf,
515 size_t length, loff_t *offset)
516{
517 file_private_info_t *p_info;
518 int rc = 0;
519
520 mutex_lock(&debug_mutex);
521 p_info = ((file_private_info_t *) file->private_data);
522 if (p_info->view->input_proc) {
523 rc = p_info->view->input_proc(p_info->debug_info_org,
524 p_info->view, file, user_buf,
525 length, offset);
526 } else {
527 rc = -EPERM;
528 }
529 mutex_unlock(&debug_mutex);
530 return rc; /* number of input characters */
531}
532
533/*
534 * debug_open:
535 * - called for user open()
536 * - copies formatted output to private_data area of the file
537 * handle
538 */
539static int debug_open(struct inode *inode, struct file *file)
540{
541 debug_info_t *debug_info, *debug_info_snapshot;
542 file_private_info_t *p_info;
543 int i, rc = 0;
544
545 mutex_lock(&debug_mutex);
546 debug_info = file_inode(file)->i_private;
547 /* find debug view */
548 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
549 if (!debug_info->views[i])
550 continue;
551 else if (debug_info->debugfs_entries[i] == file->f_path.dentry)
552 goto found; /* found view ! */
553 }
554 /* no entry found */
555 rc = -EINVAL;
556 goto out;
557
558found:
559
560 /* Make snapshot of current debug areas to get it consistent. */
561 /* To copy all the areas is only needed, if we have a view which */
562 /* formats the debug areas. */
563
564 if (!debug_info->views[i]->format_proc && !debug_info->views[i]->header_proc)
565 debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
566 else
567 debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
568
569 if (!debug_info_snapshot) {
570 rc = -ENOMEM;
571 goto out;
572 }
573 p_info = kmalloc(sizeof(file_private_info_t), GFP_KERNEL);
574 if (!p_info) {
575 debug_info_free(debug_info_snapshot);
576 rc = -ENOMEM;
577 goto out;
578 }
579 p_info->offset = 0;
580 p_info->debug_info_snap = debug_info_snapshot;
581 p_info->debug_info_org = debug_info;
582 p_info->view = debug_info->views[i];
583 p_info->act_area = 0;
584 p_info->act_page = 0;
585 p_info->act_entry = DEBUG_PROLOG_ENTRY;
586 p_info->act_entry_offset = 0;
587 file->private_data = p_info;
588 debug_info_get(debug_info);
589 nonseekable_open(inode, file);
590out:
591 mutex_unlock(&debug_mutex);
592 return rc;
593}
594
595/*
596 * debug_close:
597 * - called for user close()
598 * - deletes private_data area of the file handle
599 */
600static int debug_close(struct inode *inode, struct file *file)
601{
602 file_private_info_t *p_info;
603
604 p_info = (file_private_info_t *) file->private_data;
605 if (p_info->debug_info_snap)
606 debug_info_free(p_info->debug_info_snap);
607 debug_info_put(p_info->debug_info_org);
608 kfree(file->private_data);
609 return 0; /* success */
610}
611
612/* Create debugfs entries and add to internal list. */
613static void _debug_register(debug_info_t *id)
614{
615 /* create root directory */
616 id->debugfs_root_entry = debugfs_create_dir(id->name,
617 debug_debugfs_root_entry);
618
619 /* append new element to linked list */
620 if (!debug_area_first) {
621 /* first element in list */
622 debug_area_first = id;
623 id->prev = NULL;
624 } else {
625 /* append element to end of list */
626 debug_area_last->next = id;
627 id->prev = debug_area_last;
628 }
629 debug_area_last = id;
630 id->next = NULL;
631
632 debug_register_view(id, &debug_level_view);
633 debug_register_view(id, &debug_flush_view);
634 debug_register_view(id, &debug_pages_view);
635}
636
637/**
638 * debug_register_mode() - creates and initializes debug area.
639 *
640 * @name: Name of debug log (e.g. used for debugfs entry)
641 * @pages_per_area: Number of pages, which will be allocated per area
642 * @nr_areas: Number of debug areas
643 * @buf_size: Size of data area in each debug entry
644 * @mode: File mode for debugfs files. E.g. S_IRWXUGO
645 * @uid: User ID for debugfs files. Currently only 0 is supported.
646 * @gid: Group ID for debugfs files. Currently only 0 is supported.
647 *
648 * Return:
649 * - Handle for generated debug area
650 * - %NULL if register failed
651 *
652 * Allocates memory for a debug log.
653 * Must not be called within an interrupt handler.
654 */
655debug_info_t *debug_register_mode(const char *name, int pages_per_area,
656 int nr_areas, int buf_size, umode_t mode,
657 uid_t uid, gid_t gid)
658{
659 debug_info_t *rc = NULL;
660
661 /* Since debugfs currently does not support uid/gid other than root, */
662 /* we do not allow gid/uid != 0 until we get support for that. */
663 if ((uid != 0) || (gid != 0))
664 pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
665 BUG_ON(!initialized);
666
667 /* create new debug_info */
668 rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
669 if (rc) {
670 mutex_lock(&debug_mutex);
671 _debug_register(rc);
672 mutex_unlock(&debug_mutex);
673 } else {
674 pr_err("Registering debug feature %s failed\n", name);
675 }
676 return rc;
677}
678EXPORT_SYMBOL(debug_register_mode);
679
680/**
681 * debug_register() - creates and initializes debug area with default file mode.
682 *
683 * @name: Name of debug log (e.g. used for debugfs entry)
684 * @pages_per_area: Number of pages, which will be allocated per area
685 * @nr_areas: Number of debug areas
686 * @buf_size: Size of data area in each debug entry
687 *
688 * Return:
689 * - Handle for generated debug area
690 * - %NULL if register failed
691 *
692 * Allocates memory for a debug log.
693 * The debugfs file mode access permissions are read and write for user.
694 * Must not be called within an interrupt handler.
695 */
696debug_info_t *debug_register(const char *name, int pages_per_area,
697 int nr_areas, int buf_size)
698{
699 return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
700 S_IRUSR | S_IWUSR, 0, 0);
701}
702EXPORT_SYMBOL(debug_register);
703
704/**
705 * debug_register_static() - registers a static debug area
706 *
707 * @id: Handle for static debug area
708 * @pages_per_area: Number of pages per area
709 * @nr_areas: Number of debug areas
710 *
711 * Register debug_info_t defined using DEFINE_STATIC_DEBUG_INFO.
712 *
713 * Note: This function is called automatically via an initcall generated by
714 * DEFINE_STATIC_DEBUG_INFO.
715 */
716void debug_register_static(debug_info_t *id, int pages_per_area, int nr_areas)
717{
718 unsigned long flags;
719 debug_info_t *copy;
720
721 if (!initialized) {
722 pr_err("Tried to register debug feature %s too early\n",
723 id->name);
724 return;
725 }
726
727 copy = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
728 id->level, ALL_AREAS);
729 if (!copy) {
730 pr_err("Registering debug feature %s failed\n", id->name);
731
732 /* Clear pointers to prevent tracing into released initdata. */
733 spin_lock_irqsave(&id->lock, flags);
734 id->areas = NULL;
735 id->active_pages = NULL;
736 id->active_entries = NULL;
737 spin_unlock_irqrestore(&id->lock, flags);
738
739 return;
740 }
741
742 /* Replace static trace area with dynamic copy. */
743 spin_lock_irqsave(&id->lock, flags);
744 debug_events_append(copy, id);
745 debug_areas_swap(id, copy);
746 spin_unlock_irqrestore(&id->lock, flags);
747
748 /* Clear pointers to initdata and discard copy. */
749 copy->areas = NULL;
750 copy->active_pages = NULL;
751 copy->active_entries = NULL;
752 debug_info_free(copy);
753
754 mutex_lock(&debug_mutex);
755 _debug_register(id);
756 mutex_unlock(&debug_mutex);
757}
758
759/* Remove debugfs entries and remove from internal list. */
760static void _debug_unregister(debug_info_t *id)
761{
762 int i;
763
764 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
765 if (!id->views[i])
766 continue;
767 debugfs_remove(id->debugfs_entries[i]);
768 }
769 debugfs_remove(id->debugfs_root_entry);
770 if (id == debug_area_first)
771 debug_area_first = id->next;
772 if (id == debug_area_last)
773 debug_area_last = id->prev;
774 if (id->prev)
775 id->prev->next = id->next;
776 if (id->next)
777 id->next->prev = id->prev;
778}
779
780/**
781 * debug_unregister() - give back debug area.
782 *
783 * @id: handle for debug log
784 *
785 * Return:
786 * none
787 */
788void debug_unregister(debug_info_t *id)
789{
790 if (!id)
791 return;
792 mutex_lock(&debug_mutex);
793 _debug_unregister(id);
794 mutex_unlock(&debug_mutex);
795
796 debug_info_put(id);
797}
798EXPORT_SYMBOL(debug_unregister);
799
800/*
801 * debug_set_size:
802 * - set area size (number of pages) and number of areas
803 */
804static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
805{
806 debug_info_t *new_id;
807 unsigned long flags;
808
809 if (!id || (nr_areas <= 0) || (pages_per_area < 0))
810 return -EINVAL;
811
812 new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
813 id->level, ALL_AREAS);
814 if (!new_id) {
815 pr_info("Allocating memory for %i pages failed\n",
816 pages_per_area);
817 return -ENOMEM;
818 }
819
820 spin_lock_irqsave(&id->lock, flags);
821 debug_events_append(new_id, id);
822 debug_areas_swap(new_id, id);
823 debug_info_free(new_id);
824 spin_unlock_irqrestore(&id->lock, flags);
825 pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
826
827 return 0;
828}
829
830/**
831 * debug_set_level() - Sets new actual debug level if new_level is valid.
832 *
833 * @id: handle for debug log
834 * @new_level: new debug level
835 *
836 * Return:
837 * none
838 */
839void debug_set_level(debug_info_t *id, int new_level)
840{
841 unsigned long flags;
842
843 if (!id)
844 return;
845
846 if (new_level == DEBUG_OFF_LEVEL) {
847 pr_info("%s: switched off\n", id->name);
848 } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
849 pr_info("%s: level %i is out of range (%i - %i)\n",
850 id->name, new_level, 0, DEBUG_MAX_LEVEL);
851 return;
852 }
853
854 spin_lock_irqsave(&id->lock, flags);
855 id->level = new_level;
856 spin_unlock_irqrestore(&id->lock, flags);
857}
858EXPORT_SYMBOL(debug_set_level);
859
860/*
861 * proceed_active_entry:
862 * - set active entry to next in the ring buffer
863 */
864static inline void proceed_active_entry(debug_info_t *id)
865{
866 if ((id->active_entries[id->active_area] += id->entry_size)
867 > (PAGE_SIZE - id->entry_size)) {
868 id->active_entries[id->active_area] = 0;
869 id->active_pages[id->active_area] =
870 (id->active_pages[id->active_area] + 1) %
871 id->pages_per_area;
872 }
873}
874
875/*
876 * proceed_active_area:
877 * - set active area to next in the ring buffer
878 */
879static inline void proceed_active_area(debug_info_t *id)
880{
881 id->active_area++;
882 id->active_area = id->active_area % id->nr_areas;
883}
884
885/*
886 * get_active_entry:
887 */
888static inline debug_entry_t *get_active_entry(debug_info_t *id)
889{
890 return (debug_entry_t *) (((char *) id->areas[id->active_area]
891 [id->active_pages[id->active_area]]) +
892 id->active_entries[id->active_area]);
893}
894
895/* Swap debug areas of a and b. */
896static void debug_areas_swap(debug_info_t *a, debug_info_t *b)
897{
898 swap(a->nr_areas, b->nr_areas);
899 swap(a->pages_per_area, b->pages_per_area);
900 swap(a->areas, b->areas);
901 swap(a->active_area, b->active_area);
902 swap(a->active_pages, b->active_pages);
903 swap(a->active_entries, b->active_entries);
904}
905
906/* Append all debug events in active area from source to destination log. */
907static void debug_events_append(debug_info_t *dest, debug_info_t *src)
908{
909 debug_entry_t *from, *to, *last;
910
911 if (!src->areas || !dest->areas)
912 return;
913
914 /* Loop over all entries in src, starting with oldest. */
915 from = get_active_entry(src);
916 last = from;
917 do {
918 if (from->clock != 0LL) {
919 to = get_active_entry(dest);
920 memset(to, 0, dest->entry_size);
921 memcpy(to, from, min(src->entry_size,
922 dest->entry_size));
923 proceed_active_entry(dest);
924 }
925
926 proceed_active_entry(src);
927 from = get_active_entry(src);
928 } while (from != last);
929}
930
931/*
932 * debug_finish_entry:
933 * - set timestamp, caller address, cpu number etc.
934 */
935
936static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
937 int level, int exception)
938{
939 unsigned long timestamp;
940 union tod_clock clk;
941
942 store_tod_clock_ext(&clk);
943 timestamp = clk.us;
944 timestamp -= TOD_UNIX_EPOCH >> 12;
945 active->clock = timestamp;
946 active->cpu = smp_processor_id();
947 active->caller = __builtin_return_address(0);
948 active->exception = exception;
949 active->level = level;
950 proceed_active_entry(id);
951 if (exception)
952 proceed_active_area(id);
953}
954
955static int debug_stoppable = 1;
956static int debug_active = 1;
957
958#define CTL_S390DBF_STOPPABLE 5678
959#define CTL_S390DBF_ACTIVE 5679
960
961/*
962 * proc handler for the running debug_active sysctl
963 * always allow read, allow write only if debug_stoppable is set or
964 * if debug_active is already off
965 */
966static int s390dbf_procactive(const struct ctl_table *table, int write,
967 void *buffer, size_t *lenp, loff_t *ppos)
968{
969 if (!write || debug_stoppable || !debug_active)
970 return proc_dointvec(table, write, buffer, lenp, ppos);
971 else
972 return 0;
973}
974
975static struct ctl_table s390dbf_table[] = {
976 {
977 .procname = "debug_stoppable",
978 .data = &debug_stoppable,
979 .maxlen = sizeof(int),
980 .mode = S_IRUGO | S_IWUSR,
981 .proc_handler = proc_dointvec,
982 },
983 {
984 .procname = "debug_active",
985 .data = &debug_active,
986 .maxlen = sizeof(int),
987 .mode = S_IRUGO | S_IWUSR,
988 .proc_handler = s390dbf_procactive,
989 },
990};
991
992static struct ctl_table_header *s390dbf_sysctl_header;
993
994/**
995 * debug_stop_all() - stops the debug feature if stopping is allowed.
996 *
997 * Return:
998 * - none
999 *
1000 * Currently used in case of a kernel oops.
1001 */
1002void debug_stop_all(void)
1003{
1004 if (debug_stoppable)
1005 debug_active = 0;
1006}
1007EXPORT_SYMBOL(debug_stop_all);
1008
1009/**
1010 * debug_set_critical() - event/exception functions try lock instead of spin.
1011 *
1012 * Return:
1013 * - none
1014 *
1015 * Currently used in case of stopping all CPUs but the current one.
1016 * Once in this state, functions to write a debug entry for an
1017 * event or exception no longer spin on the debug area lock,
1018 * but only try to get it and fail if they do not get the lock.
1019 */
1020void debug_set_critical(void)
1021{
1022 debug_critical = 1;
1023}
1024
1025/*
1026 * debug_event_common:
1027 * - write debug entry with given size
1028 */
1029debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
1030 int len)
1031{
1032 debug_entry_t *active;
1033 unsigned long flags;
1034
1035 if (!debug_active || !id->areas)
1036 return NULL;
1037 if (debug_critical) {
1038 if (!spin_trylock_irqsave(&id->lock, flags))
1039 return NULL;
1040 } else {
1041 spin_lock_irqsave(&id->lock, flags);
1042 }
1043 do {
1044 active = get_active_entry(id);
1045 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1046 if (len < id->buf_size)
1047 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1048 debug_finish_entry(id, active, level, 0);
1049 len -= id->buf_size;
1050 buf += id->buf_size;
1051 } while (len > 0);
1052
1053 spin_unlock_irqrestore(&id->lock, flags);
1054 return active;
1055}
1056EXPORT_SYMBOL(debug_event_common);
1057
1058/*
1059 * debug_exception_common:
1060 * - write debug entry with given size and switch to next debug area
1061 */
1062debug_entry_t *debug_exception_common(debug_info_t *id, int level,
1063 const void *buf, int len)
1064{
1065 debug_entry_t *active;
1066 unsigned long flags;
1067
1068 if (!debug_active || !id->areas)
1069 return NULL;
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 do {
1077 active = get_active_entry(id);
1078 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1079 if (len < id->buf_size)
1080 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1081 debug_finish_entry(id, active, level, len <= id->buf_size);
1082 len -= id->buf_size;
1083 buf += id->buf_size;
1084 } while (len > 0);
1085
1086 spin_unlock_irqrestore(&id->lock, flags);
1087 return active;
1088}
1089EXPORT_SYMBOL(debug_exception_common);
1090
1091/*
1092 * counts arguments in format string for sprintf view
1093 */
1094static inline int debug_count_numargs(char *string)
1095{
1096 int numargs = 0;
1097
1098 while (*string) {
1099 if (*string++ == '%')
1100 numargs++;
1101 }
1102 return numargs;
1103}
1104
1105/*
1106 * debug_sprintf_event:
1107 */
1108debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
1109{
1110 debug_sprintf_entry_t *curr_event;
1111 debug_entry_t *active;
1112 unsigned long flags;
1113 int numargs, idx;
1114 va_list ap;
1115
1116 if (!debug_active || !id->areas)
1117 return NULL;
1118 numargs = debug_count_numargs(string);
1119
1120 if (debug_critical) {
1121 if (!spin_trylock_irqsave(&id->lock, flags))
1122 return NULL;
1123 } else {
1124 spin_lock_irqsave(&id->lock, flags);
1125 }
1126 active = get_active_entry(id);
1127 curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
1128 va_start(ap, string);
1129 curr_event->string = string;
1130 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1131 curr_event->args[idx] = va_arg(ap, long);
1132 va_end(ap);
1133 debug_finish_entry(id, active, level, 0);
1134 spin_unlock_irqrestore(&id->lock, flags);
1135
1136 return active;
1137}
1138EXPORT_SYMBOL(__debug_sprintf_event);
1139
1140/*
1141 * debug_sprintf_exception:
1142 */
1143debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1144{
1145 debug_sprintf_entry_t *curr_event;
1146 debug_entry_t *active;
1147 unsigned long flags;
1148 int numargs, idx;
1149 va_list ap;
1150
1151 if (!debug_active || !id->areas)
1152 return NULL;
1153
1154 numargs = debug_count_numargs(string);
1155
1156 if (debug_critical) {
1157 if (!spin_trylock_irqsave(&id->lock, flags))
1158 return NULL;
1159 } else {
1160 spin_lock_irqsave(&id->lock, flags);
1161 }
1162 active = get_active_entry(id);
1163 curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
1164 va_start(ap, string);
1165 curr_event->string = string;
1166 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1167 curr_event->args[idx] = va_arg(ap, long);
1168 va_end(ap);
1169 debug_finish_entry(id, active, level, 1);
1170 spin_unlock_irqrestore(&id->lock, flags);
1171
1172 return active;
1173}
1174EXPORT_SYMBOL(__debug_sprintf_exception);
1175
1176/**
1177 * debug_register_view() - registers new debug view and creates debugfs
1178 * dir entry
1179 *
1180 * @id: handle for debug log
1181 * @view: pointer to debug view struct
1182 *
1183 * Return:
1184 * - 0 : ok
1185 * - < 0: Error
1186 */
1187int debug_register_view(debug_info_t *id, struct debug_view *view)
1188{
1189 unsigned long flags;
1190 struct dentry *pde;
1191 umode_t mode;
1192 int rc = 0;
1193 int i;
1194
1195 if (!id)
1196 goto out;
1197 mode = (id->mode | S_IFREG) & ~S_IXUGO;
1198 if (!(view->prolog_proc || view->format_proc || view->header_proc))
1199 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1200 if (!view->input_proc)
1201 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1202 pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1203 id, &debug_file_ops);
1204 spin_lock_irqsave(&id->lock, flags);
1205 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1206 if (!id->views[i])
1207 break;
1208 }
1209 if (i == DEBUG_MAX_VIEWS) {
1210 rc = -1;
1211 } else {
1212 id->views[i] = view;
1213 id->debugfs_entries[i] = pde;
1214 }
1215 spin_unlock_irqrestore(&id->lock, flags);
1216 if (rc) {
1217 pr_err("Registering view %s/%s would exceed the maximum "
1218 "number of views %i\n", id->name, view->name, i);
1219 debugfs_remove(pde);
1220 }
1221out:
1222 return rc;
1223}
1224EXPORT_SYMBOL(debug_register_view);
1225
1226/**
1227 * debug_unregister_view() - unregisters debug view and removes debugfs
1228 * dir entry
1229 *
1230 * @id: handle for debug log
1231 * @view: pointer to debug view struct
1232 *
1233 * Return:
1234 * - 0 : ok
1235 * - < 0: Error
1236 */
1237int debug_unregister_view(debug_info_t *id, struct debug_view *view)
1238{
1239 struct dentry *dentry = NULL;
1240 unsigned long flags;
1241 int i, rc = 0;
1242
1243 if (!id)
1244 goto out;
1245 spin_lock_irqsave(&id->lock, flags);
1246 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1247 if (id->views[i] == view)
1248 break;
1249 }
1250 if (i == DEBUG_MAX_VIEWS) {
1251 rc = -1;
1252 } else {
1253 dentry = id->debugfs_entries[i];
1254 id->views[i] = NULL;
1255 id->debugfs_entries[i] = NULL;
1256 }
1257 spin_unlock_irqrestore(&id->lock, flags);
1258 debugfs_remove(dentry);
1259out:
1260 return rc;
1261}
1262EXPORT_SYMBOL(debug_unregister_view);
1263
1264static inline char *debug_get_user_string(const char __user *user_buf,
1265 size_t user_len)
1266{
1267 char *buffer;
1268
1269 buffer = kmalloc(user_len + 1, GFP_KERNEL);
1270 if (!buffer)
1271 return ERR_PTR(-ENOMEM);
1272 if (copy_from_user(buffer, user_buf, user_len) != 0) {
1273 kfree(buffer);
1274 return ERR_PTR(-EFAULT);
1275 }
1276 /* got the string, now strip linefeed. */
1277 if (buffer[user_len - 1] == '\n')
1278 buffer[user_len - 1] = 0;
1279 else
1280 buffer[user_len] = 0;
1281 return buffer;
1282}
1283
1284static inline int debug_get_uint(char *buf)
1285{
1286 int rc;
1287
1288 buf = skip_spaces(buf);
1289 rc = simple_strtoul(buf, &buf, 10);
1290 if (*buf)
1291 rc = -EINVAL;
1292 return rc;
1293}
1294
1295/*
1296 * functions for debug-views
1297 ***********************************
1298*/
1299
1300/*
1301 * prints out actual debug level
1302 */
1303
1304static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
1305 char *out_buf, size_t out_buf_size)
1306{
1307 return scnprintf(out_buf, out_buf_size, "%i\n", id->pages_per_area);
1308}
1309
1310/*
1311 * reads new size (number of pages per debug area)
1312 */
1313
1314static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
1315 struct file *file, const char __user *user_buf,
1316 size_t user_len, loff_t *offset)
1317{
1318 int rc, new_pages;
1319 char *str;
1320
1321 if (user_len > 0x10000)
1322 user_len = 0x10000;
1323 if (*offset != 0) {
1324 rc = -EPIPE;
1325 goto out;
1326 }
1327 str = debug_get_user_string(user_buf, user_len);
1328 if (IS_ERR(str)) {
1329 rc = PTR_ERR(str);
1330 goto out;
1331 }
1332 new_pages = debug_get_uint(str);
1333 if (new_pages < 0) {
1334 rc = -EINVAL;
1335 goto free_str;
1336 }
1337 rc = debug_set_size(id, id->nr_areas, new_pages);
1338 if (rc != 0) {
1339 rc = -EINVAL;
1340 goto free_str;
1341 }
1342 rc = user_len;
1343free_str:
1344 kfree(str);
1345out:
1346 *offset += user_len;
1347 return rc; /* number of input characters */
1348}
1349
1350/*
1351 * prints out actual debug level
1352 */
1353static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
1354 char *out_buf, size_t out_buf_size)
1355{
1356 int rc = 0;
1357
1358 if (id->level == DEBUG_OFF_LEVEL)
1359 rc = scnprintf(out_buf, out_buf_size, "-\n");
1360 else
1361 rc = scnprintf(out_buf, out_buf_size, "%i\n", id->level);
1362 return rc;
1363}
1364
1365/*
1366 * reads new debug level
1367 */
1368static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
1369 struct file *file, const char __user *user_buf,
1370 size_t user_len, loff_t *offset)
1371{
1372 int rc, new_level;
1373 char *str;
1374
1375 if (user_len > 0x10000)
1376 user_len = 0x10000;
1377 if (*offset != 0) {
1378 rc = -EPIPE;
1379 goto out;
1380 }
1381 str = debug_get_user_string(user_buf, user_len);
1382 if (IS_ERR(str)) {
1383 rc = PTR_ERR(str);
1384 goto out;
1385 }
1386 if (str[0] == '-') {
1387 debug_set_level(id, DEBUG_OFF_LEVEL);
1388 rc = user_len;
1389 goto free_str;
1390 } else {
1391 new_level = debug_get_uint(str);
1392 }
1393 if (new_level < 0) {
1394 pr_warn("%s is not a valid level for a debug feature\n", str);
1395 rc = -EINVAL;
1396 } else {
1397 debug_set_level(id, new_level);
1398 rc = user_len;
1399 }
1400free_str:
1401 kfree(str);
1402out:
1403 *offset += user_len;
1404 return rc; /* number of input characters */
1405}
1406
1407/*
1408 * flushes debug areas
1409 */
1410static void debug_flush(debug_info_t *id, int area)
1411{
1412 unsigned long flags;
1413 int i, j;
1414
1415 if (!id || !id->areas)
1416 return;
1417 spin_lock_irqsave(&id->lock, flags);
1418 if (area == DEBUG_FLUSH_ALL) {
1419 id->active_area = 0;
1420 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1421 for (i = 0; i < id->nr_areas; i++) {
1422 id->active_pages[i] = 0;
1423 for (j = 0; j < id->pages_per_area; j++)
1424 memset(id->areas[i][j], 0, PAGE_SIZE);
1425 }
1426 } else if (area >= 0 && area < id->nr_areas) {
1427 id->active_entries[area] = 0;
1428 id->active_pages[area] = 0;
1429 for (i = 0; i < id->pages_per_area; i++)
1430 memset(id->areas[area][i], 0, PAGE_SIZE);
1431 }
1432 spin_unlock_irqrestore(&id->lock, flags);
1433}
1434
1435/*
1436 * view function: flushes debug areas
1437 */
1438static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
1439 struct file *file, const char __user *user_buf,
1440 size_t user_len, loff_t *offset)
1441{
1442 char input_buf[1];
1443 int rc = user_len;
1444
1445 if (user_len > 0x10000)
1446 user_len = 0x10000;
1447 if (*offset != 0) {
1448 rc = -EPIPE;
1449 goto out;
1450 }
1451 if (copy_from_user(input_buf, user_buf, 1)) {
1452 rc = -EFAULT;
1453 goto out;
1454 }
1455 if (input_buf[0] == '-') {
1456 debug_flush(id, DEBUG_FLUSH_ALL);
1457 goto out;
1458 }
1459 if (isdigit(input_buf[0])) {
1460 int area = ((int) input_buf[0] - (int) '0');
1461
1462 debug_flush(id, area);
1463 goto out;
1464 }
1465
1466 pr_info("Flushing debug data failed because %c is not a valid "
1467 "area\n", input_buf[0]);
1468
1469out:
1470 *offset += user_len;
1471 return rc; /* number of input characters */
1472}
1473
1474/*
1475 * prints debug data in hex/ascii format
1476 */
1477static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
1478 char *out_buf, size_t out_buf_size, const char *in_buf)
1479{
1480 int i, rc = 0;
1481
1482 for (i = 0; i < id->buf_size; i++) {
1483 rc += scnprintf(out_buf + rc, out_buf_size - rc,
1484 "%02x ", ((unsigned char *)in_buf)[i]);
1485 }
1486 rc += scnprintf(out_buf + rc, out_buf_size - rc, "| ");
1487 for (i = 0; i < id->buf_size; i++) {
1488 unsigned char c = in_buf[i];
1489
1490 if (isascii(c) && isprint(c))
1491 rc += scnprintf(out_buf + rc, out_buf_size - rc, "%c", c);
1492 else
1493 rc += scnprintf(out_buf + rc, out_buf_size - rc, ".");
1494 }
1495 rc += scnprintf(out_buf + rc, out_buf_size - rc, "\n");
1496 return rc;
1497}
1498
1499/*
1500 * prints header for debug entry
1501 */
1502int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
1503 int area, debug_entry_t *entry, char *out_buf,
1504 size_t out_buf_size)
1505{
1506 unsigned long sec, usec;
1507 unsigned long caller;
1508 unsigned int level;
1509 char *except_str;
1510 int rc = 0;
1511
1512 level = entry->level;
1513 sec = entry->clock;
1514 usec = do_div(sec, USEC_PER_SEC);
1515
1516 if (entry->exception)
1517 except_str = "*";
1518 else
1519 except_str = "-";
1520 caller = (unsigned long) entry->caller;
1521 rc += scnprintf(out_buf, out_buf_size, "%02i %011ld:%06lu %1u %1s %04u %px ",
1522 area, sec, usec, level, except_str,
1523 entry->cpu, (void *)caller);
1524 return rc;
1525}
1526EXPORT_SYMBOL(debug_dflt_header_fn);
1527
1528/*
1529 * prints debug data sprintf-formatted:
1530 * debug_sprinf_event/exception calls must be used together with this view
1531 */
1532
1533#define DEBUG_SPRINTF_MAX_ARGS 10
1534
1535static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
1536 char *out_buf, size_t out_buf_size, const char *inbuf)
1537{
1538 debug_sprintf_entry_t *curr_event = (debug_sprintf_entry_t *)inbuf;
1539 int num_longs, num_used_args = 0, i, rc = 0;
1540 int index[DEBUG_SPRINTF_MAX_ARGS];
1541
1542 /* count of longs fit into one entry */
1543 num_longs = id->buf_size / sizeof(long);
1544
1545 if (num_longs < 1)
1546 goto out; /* bufsize of entry too small */
1547 if (num_longs == 1) {
1548 /* no args, we use only the string */
1549 rc = strscpy(out_buf, curr_event->string, out_buf_size);
1550 if (rc == -E2BIG)
1551 rc = out_buf_size;
1552 goto out;
1553 }
1554
1555 /* number of arguments used for sprintf (without the format string) */
1556 num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1557
1558 memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1559
1560 for (i = 0; i < num_used_args; i++)
1561 index[i] = i;
1562
1563 rc = scnprintf(out_buf, out_buf_size,
1564 curr_event->string, curr_event->args[index[0]],
1565 curr_event->args[index[1]], curr_event->args[index[2]],
1566 curr_event->args[index[3]], curr_event->args[index[4]],
1567 curr_event->args[index[5]], curr_event->args[index[6]],
1568 curr_event->args[index[7]], curr_event->args[index[8]],
1569 curr_event->args[index[9]]);
1570out:
1571 return rc;
1572}
1573
1574/*
1575 * debug_init:
1576 * - is called exactly once to initialize the debug feature
1577 */
1578static int __init debug_init(void)
1579{
1580 s390dbf_sysctl_header = register_sysctl("s390dbf", s390dbf_table);
1581 mutex_lock(&debug_mutex);
1582 debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1583 initialized = 1;
1584 mutex_unlock(&debug_mutex);
1585 return 0;
1586}
1587postcore_initcall(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
38typedef 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
54typedef 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
67static int debug_init(void);
68static ssize_t debug_output(struct file *file, char __user *user_buf,
69 size_t user_len, loff_t *offset);
70static ssize_t debug_input(struct file *file, const char __user *user_buf,
71 size_t user_len, loff_t *offset);
72static int debug_open(struct inode *inode, struct file *file);
73static int debug_close(struct inode *inode, struct file *file);
74static debug_info_t *debug_info_create(const char *name, int pages_per_area,
75 int nr_areas, int buf_size, umode_t mode);
76static void debug_info_get(debug_info_t *);
77static void debug_info_put(debug_info_t *);
78static int debug_prolog_level_fn(debug_info_t *id,
79 struct debug_view *view, char *out_buf);
80static 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);
83static int debug_prolog_pages_fn(debug_info_t *id,
84 struct debug_view *view, char *out_buf);
85static 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);
88static 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);
91static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
92 char *out_buf, const char *in_buf);
93static int debug_raw_format_fn(debug_info_t *id,
94 struct debug_view *view, char *out_buf,
95 const char *in_buf);
96static int debug_raw_header_fn(debug_info_t *id, struct debug_view *view,
97 int area, debug_entry_t *entry, char *out_buf);
98
99static 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
104struct debug_view debug_raw_view = {
105 "raw",
106 NULL,
107 &debug_raw_header_fn,
108 &debug_raw_format_fn,
109 NULL,
110 NULL
111};
112EXPORT_SYMBOL(debug_raw_view);
113
114struct 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};
122EXPORT_SYMBOL(debug_hex_ascii_view);
123
124static 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
133static 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
142static struct debug_view debug_flush_view = {
143 "flush",
144 NULL,
145 NULL,
146 NULL,
147 &debug_input_flush_fn,
148 NULL
149};
150
151struct 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};
159EXPORT_SYMBOL(debug_sprintf_view);
160
161/* used by dump analysis tools to determine version of debug feature */
162static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
163
164/* static globals */
165
166static debug_info_t *debug_area_first;
167static debug_info_t *debug_area_last;
168static DEFINE_MUTEX(debug_mutex);
169
170static int initialized;
171static int debug_critical;
172
173static 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
182static 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
192static 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
218fail_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);
225fail_malloc_areas:
226 return NULL;
227}
228
229/*
230 * debug_info_alloc
231 * - alloc new debug-info
232 */
233static 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
272fail_malloc_areas:
273 kfree(rc->active_pages);
274fail_malloc_active_pages:
275 kfree(rc->active_entries);
276fail_malloc_active_entries:
277 kfree(rc);
278fail_malloc_rc:
279 return NULL;
280}
281
282/*
283 * debug_areas_free
284 * - free all debug areas
285 */
286static 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 */
305static 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
318static 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);
348out:
349 return rc;
350}
351
352/*
353 * debug_info_copy
354 * - copy debug-info
355 */
356static 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 }
385out:
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 */
394static 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 */
404static 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 */
433static 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));
459out:
460 return len;
461}
462
463/*
464 * debug_next_entry:
465 * - goto next entry in p_info
466 */
467static 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 }
493out:
494 return 0;
495}
496
497/*
498 * debug_output:
499 * - called for user read()
500 * - copies formated debug entries to the user buffer
501 */
502static 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 }
540out:
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 */
552static 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 */
577static 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
596found:
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);
628out:
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 */
638static 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 */
668debug_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);
688out:
689 if (!rc)
690 pr_err("Registering debug feature %s failed\n", name);
691 mutex_unlock(&debug_mutex);
692 return rc;
693}
694EXPORT_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 */
712debug_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}
718EXPORT_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 */
728void 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}
736EXPORT_SYMBOL(debug_unregister);
737
738/*
739 * debug_set_size:
740 * - set area size (number of pages) and number of areas
741 */
742static 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);
771out:
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 */
784void 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}
802EXPORT_SYMBOL(debug_set_level);
803
804/*
805 * proceed_active_entry:
806 * - set active entry to next in the ring buffer
807 */
808static 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 */
823static 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 */
832static 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
844static 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
858static int debug_stoppable = 1;
859static 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 */
869static 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
878static 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
896static 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
906static 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 */
916void debug_stop_all(void)
917{
918 if (debug_stoppable)
919 debug_active = 0;
920}
921EXPORT_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 */
934void debug_set_critical(void)
935{
936 debug_critical = 1;
937}
938
939/*
940 * debug_event_common:
941 * - write debug entry with given size
942 */
943debug_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}
970EXPORT_SYMBOL(debug_event_common);
971
972/*
973 * debug_exception_common:
974 * - write debug entry with given size and switch to next debug area
975 */
976debug_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}
1003EXPORT_SYMBOL(debug_exception_common);
1004
1005/*
1006 * counts arguments in format string for sprintf view
1007 */
1008static 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 */
1022debug_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}
1052EXPORT_SYMBOL(__debug_sprintf_event);
1053
1054/*
1055 * debug_sprintf_exception:
1056 */
1057debug_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}
1088EXPORT_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 */
1101int 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);
1134out:
1135 return rc;
1136}
1137EXPORT_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 */
1150int 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);
1172out:
1173 return rc;
1174}
1175EXPORT_SYMBOL(debug_unregister_view);
1176
1177static 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
1197static 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
1217static 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
1227static 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;
1256free_str:
1257 kfree(str);
1258out:
1259 *offset += user_len;
1260 return rc; /* number of input characters */
1261}
1262
1263/*
1264 * prints out actual debug level
1265 */
1266static 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 */
1281static 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 }
1313free_str:
1314 kfree(str);
1315out:
1316 *offset += user_len;
1317 return rc; /* number of input characters */
1318}
1319
1320/*
1321 * flushes debug areas
1322 */
1323static 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 */
1351static 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
1382out:
1383 *offset += user_len;
1384 return rc; /* number of input characters */
1385}
1386
1387/*
1388 * prints debug header in raw format
1389 */
1390static 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 */
1403static 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 */
1416static 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 */
1439int 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}
1463EXPORT_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
1472static 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]]);
1504out:
1505 return rc;
1506}
1507
1508/*
1509 * debug_init:
1510 * - is called exactly once to initialize the debug feature
1511 */
1512static 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}
1521postcore_initcall(debug_init);