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