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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/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 formated area */
42 int act_page; /* act page in given area */
43 int act_entry; /* last formated entry (offset */
44 /* relative to beginning of last */
45 /* formated page) */
46 size_t act_entry_offset; /* up to this offset we copied */
47 /* in last read the last formated */
48 /* entry to userland */
49 char temp_buf[2048]; /* buffer for output */
50 debug_info_t *debug_info_org; /* original debug information */
51 debug_info_t *debug_info_snap; /* snapshot of debug information */
52 struct debug_view *view; /* used view of debug info */
53} file_private_info_t;
54
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[0];
64} debug_sprintf_entry_t;
65
66/* internal function prototyes */
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);
81static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
82 struct file *file, const char __user *user_buf,
83 size_t user_buf_size, loff_t *offset);
84static int debug_prolog_pages_fn(debug_info_t *id,
85 struct debug_view *view, char *out_buf);
86static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
87 struct file *file, const char __user *user_buf,
88 size_t user_buf_size, loff_t *offset);
89static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
90 struct file *file, const char __user *user_buf,
91 size_t user_buf_size, loff_t *offset);
92static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
93 char *out_buf, const char *in_buf);
94static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
95 char *out_buf, debug_sprintf_entry_t *curr_event);
96static void debug_areas_swap(debug_info_t *a, debug_info_t *b);
97static void debug_events_append(debug_info_t *dest, debug_info_t *src);
98
99/* globals */
100
101struct debug_view debug_hex_ascii_view = {
102 "hex_ascii",
103 NULL,
104 &debug_dflt_header_fn,
105 &debug_hex_ascii_format_fn,
106 NULL,
107 NULL
108};
109EXPORT_SYMBOL(debug_hex_ascii_view);
110
111static struct debug_view debug_level_view = {
112 "level",
113 &debug_prolog_level_fn,
114 NULL,
115 NULL,
116 &debug_input_level_fn,
117 NULL
118};
119
120static struct debug_view debug_pages_view = {
121 "pages",
122 &debug_prolog_pages_fn,
123 NULL,
124 NULL,
125 &debug_input_pages_fn,
126 NULL
127};
128
129static struct debug_view debug_flush_view = {
130 "flush",
131 NULL,
132 NULL,
133 NULL,
134 &debug_input_flush_fn,
135 NULL
136};
137
138struct debug_view debug_sprintf_view = {
139 "sprintf",
140 NULL,
141 &debug_dflt_header_fn,
142 (debug_format_proc_t *)&debug_sprintf_format_fn,
143 NULL,
144 NULL
145};
146EXPORT_SYMBOL(debug_sprintf_view);
147
148/* used by dump analysis tools to determine version of debug feature */
149static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
150
151/* static globals */
152
153static debug_info_t *debug_area_first;
154static debug_info_t *debug_area_last;
155static DEFINE_MUTEX(debug_mutex);
156
157static int initialized;
158static int debug_critical;
159
160static const struct file_operations debug_file_ops = {
161 .owner = THIS_MODULE,
162 .read = debug_output,
163 .write = debug_input,
164 .open = debug_open,
165 .release = debug_close,
166 .llseek = no_llseek,
167};
168
169static struct dentry *debug_debugfs_root_entry;
170
171/* functions */
172
173/*
174 * debug_areas_alloc
175 * - Debug areas are implemented as a threedimensonal array:
176 * areas[areanumber][pagenumber][pageoffset]
177 */
178
179static debug_entry_t ***debug_areas_alloc(int pages_per_area, int nr_areas)
180{
181 debug_entry_t ***areas;
182 int i, j;
183
184 areas = kmalloc_array(nr_areas, sizeof(debug_entry_t **), GFP_KERNEL);
185 if (!areas)
186 goto fail_malloc_areas;
187 for (i = 0; i < nr_areas; i++) {
188 /* GFP_NOWARN to avoid user triggerable WARN, we handle fails */
189 areas[i] = kmalloc_array(pages_per_area,
190 sizeof(debug_entry_t *),
191 GFP_KERNEL | __GFP_NOWARN);
192 if (!areas[i])
193 goto fail_malloc_areas2;
194 for (j = 0; j < pages_per_area; j++) {
195 areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
196 if (!areas[i][j]) {
197 for (j--; j >= 0 ; j--)
198 kfree(areas[i][j]);
199 kfree(areas[i]);
200 goto fail_malloc_areas2;
201 }
202 }
203 }
204 return areas;
205
206fail_malloc_areas2:
207 for (i--; i >= 0; i--) {
208 for (j = 0; j < pages_per_area; j++)
209 kfree(areas[i][j]);
210 kfree(areas[i]);
211 }
212 kfree(areas);
213fail_malloc_areas:
214 return NULL;
215}
216
217/*
218 * debug_info_alloc
219 * - alloc new debug-info
220 */
221static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,
222 int nr_areas, int buf_size, int level,
223 int mode)
224{
225 debug_info_t *rc;
226
227 /* alloc everything */
228 rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
229 if (!rc)
230 goto fail_malloc_rc;
231 rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
232 if (!rc->active_entries)
233 goto fail_malloc_active_entries;
234 rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
235 if (!rc->active_pages)
236 goto fail_malloc_active_pages;
237 if ((mode == ALL_AREAS) && (pages_per_area != 0)) {
238 rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
239 if (!rc->areas)
240 goto fail_malloc_areas;
241 } else {
242 rc->areas = NULL;
243 }
244
245 /* initialize members */
246 spin_lock_init(&rc->lock);
247 rc->pages_per_area = pages_per_area;
248 rc->nr_areas = nr_areas;
249 rc->active_area = 0;
250 rc->level = level;
251 rc->buf_size = buf_size;
252 rc->entry_size = sizeof(debug_entry_t) + buf_size;
253 strlcpy(rc->name, name, sizeof(rc->name));
254 memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
255 memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
256 refcount_set(&(rc->ref_count), 0);
257
258 return rc;
259
260fail_malloc_areas:
261 kfree(rc->active_pages);
262fail_malloc_active_pages:
263 kfree(rc->active_entries);
264fail_malloc_active_entries:
265 kfree(rc);
266fail_malloc_rc:
267 return NULL;
268}
269
270/*
271 * debug_areas_free
272 * - free all debug areas
273 */
274static void debug_areas_free(debug_info_t *db_info)
275{
276 int i, j;
277
278 if (!db_info->areas)
279 return;
280 for (i = 0; i < db_info->nr_areas; i++) {
281 for (j = 0; j < db_info->pages_per_area; j++)
282 kfree(db_info->areas[i][j]);
283 kfree(db_info->areas[i]);
284 }
285 kfree(db_info->areas);
286 db_info->areas = NULL;
287}
288
289/*
290 * debug_info_free
291 * - free memory debug-info
292 */
293static void debug_info_free(debug_info_t *db_info)
294{
295 debug_areas_free(db_info);
296 kfree(db_info->active_entries);
297 kfree(db_info->active_pages);
298 kfree(db_info);
299}
300
301/*
302 * debug_info_create
303 * - create new debug-info
304 */
305
306static debug_info_t *debug_info_create(const char *name, int pages_per_area,
307 int nr_areas, int buf_size, umode_t mode)
308{
309 debug_info_t *rc;
310
311 rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
312 DEBUG_DEFAULT_LEVEL, ALL_AREAS);
313 if (!rc)
314 goto out;
315
316 rc->mode = mode & ~S_IFMT;
317 refcount_set(&rc->ref_count, 1);
318out:
319 return rc;
320}
321
322/*
323 * debug_info_copy
324 * - copy debug-info
325 */
326static debug_info_t *debug_info_copy(debug_info_t *in, int mode)
327{
328 unsigned long flags;
329 debug_info_t *rc;
330 int i, j;
331
332 /* get a consistent copy of the debug areas */
333 do {
334 rc = debug_info_alloc(in->name, in->pages_per_area,
335 in->nr_areas, in->buf_size, in->level, mode);
336 spin_lock_irqsave(&in->lock, flags);
337 if (!rc)
338 goto out;
339 /* has something changed in the meantime ? */
340 if ((rc->pages_per_area == in->pages_per_area) &&
341 (rc->nr_areas == in->nr_areas)) {
342 break;
343 }
344 spin_unlock_irqrestore(&in->lock, flags);
345 debug_info_free(rc);
346 } while (1);
347
348 if (mode == NO_AREAS)
349 goto out;
350
351 for (i = 0; i < in->nr_areas; i++) {
352 for (j = 0; j < in->pages_per_area; j++)
353 memcpy(rc->areas[i][j], in->areas[i][j], PAGE_SIZE);
354 }
355out:
356 spin_unlock_irqrestore(&in->lock, flags);
357 return rc;
358}
359
360/*
361 * debug_info_get
362 * - increments reference count for debug-info
363 */
364static void debug_info_get(debug_info_t *db_info)
365{
366 if (db_info)
367 refcount_inc(&db_info->ref_count);
368}
369
370/*
371 * debug_info_put:
372 * - decreases reference count for debug-info and frees it if necessary
373 */
374static void debug_info_put(debug_info_t *db_info)
375{
376 if (!db_info)
377 return;
378 if (refcount_dec_and_test(&db_info->ref_count))
379 debug_info_free(db_info);
380}
381
382/*
383 * debug_format_entry:
384 * - format one debug entry and return size of formated data
385 */
386static int debug_format_entry(file_private_info_t *p_info)
387{
388 debug_info_t *id_snap = p_info->debug_info_snap;
389 struct debug_view *view = p_info->view;
390 debug_entry_t *act_entry;
391 size_t len = 0;
392
393 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
394 /* print prolog */
395 if (view->prolog_proc)
396 len += view->prolog_proc(id_snap, view, p_info->temp_buf);
397 goto out;
398 }
399 if (!id_snap->areas) /* this is true, if we have a prolog only view */
400 goto out; /* or if 'pages_per_area' is 0 */
401 act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
402 [p_info->act_page] + p_info->act_entry);
403
404 if (act_entry->clock == 0LL)
405 goto out; /* empty entry */
406 if (view->header_proc)
407 len += view->header_proc(id_snap, view, p_info->act_area,
408 act_entry, p_info->temp_buf + len);
409 if (view->format_proc)
410 len += view->format_proc(id_snap, view, p_info->temp_buf + len,
411 DEBUG_DATA(act_entry));
412out:
413 return len;
414}
415
416/*
417 * debug_next_entry:
418 * - goto next entry in p_info
419 */
420static inline int debug_next_entry(file_private_info_t *p_info)
421{
422 debug_info_t *id;
423
424 id = p_info->debug_info_snap;
425 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
426 p_info->act_entry = 0;
427 p_info->act_page = 0;
428 goto out;
429 }
430 if (!id->areas)
431 return 1;
432 p_info->act_entry += id->entry_size;
433 /* switch to next page, if we reached the end of the page */
434 if (p_info->act_entry > (PAGE_SIZE - id->entry_size)) {
435 /* next page */
436 p_info->act_entry = 0;
437 p_info->act_page += 1;
438 if ((p_info->act_page % id->pages_per_area) == 0) {
439 /* next area */
440 p_info->act_area++;
441 p_info->act_page = 0;
442 }
443 if (p_info->act_area >= id->nr_areas)
444 return 1;
445 }
446out:
447 return 0;
448}
449
450/*
451 * debug_output:
452 * - called for user read()
453 * - copies formated debug entries to the user buffer
454 */
455static ssize_t debug_output(struct file *file, /* file descriptor */
456 char __user *user_buf, /* user buffer */
457 size_t len, /* length of buffer */
458 loff_t *offset) /* offset in the file */
459{
460 size_t count = 0;
461 size_t entry_offset;
462 file_private_info_t *p_info;
463
464 p_info = (file_private_info_t *) file->private_data;
465 if (*offset != p_info->offset)
466 return -EPIPE;
467 if (p_info->act_area >= p_info->debug_info_snap->nr_areas)
468 return 0;
469 entry_offset = p_info->act_entry_offset;
470 while (count < len) {
471 int formatted_line_residue;
472 int formatted_line_size;
473 int user_buf_residue;
474 size_t copy_size;
475
476 formatted_line_size = debug_format_entry(p_info);
477 formatted_line_residue = formatted_line_size - entry_offset;
478 user_buf_residue = len-count;
479 copy_size = min(user_buf_residue, formatted_line_residue);
480 if (copy_size) {
481 if (copy_to_user(user_buf + count, p_info->temp_buf
482 + entry_offset, copy_size))
483 return -EFAULT;
484 count += copy_size;
485 entry_offset += copy_size;
486 }
487 if (copy_size == formatted_line_residue) {
488 entry_offset = 0;
489 if (debug_next_entry(p_info))
490 goto out;
491 }
492 }
493out:
494 p_info->offset = *offset + count;
495 p_info->act_entry_offset = entry_offset;
496 *offset = p_info->offset;
497 return count;
498}
499
500/*
501 * debug_input:
502 * - called for user write()
503 * - calls input function of view
504 */
505static ssize_t debug_input(struct file *file, const char __user *user_buf,
506 size_t length, loff_t *offset)
507{
508 file_private_info_t *p_info;
509 int rc = 0;
510
511 mutex_lock(&debug_mutex);
512 p_info = ((file_private_info_t *) file->private_data);
513 if (p_info->view->input_proc) {
514 rc = p_info->view->input_proc(p_info->debug_info_org,
515 p_info->view, file, user_buf,
516 length, offset);
517 } else {
518 rc = -EPERM;
519 }
520 mutex_unlock(&debug_mutex);
521 return rc; /* number of input characters */
522}
523
524/*
525 * debug_open:
526 * - called for user open()
527 * - copies formated output to private_data area of the file
528 * handle
529 */
530static int debug_open(struct inode *inode, struct file *file)
531{
532 debug_info_t *debug_info, *debug_info_snapshot;
533 file_private_info_t *p_info;
534 int i, rc = 0;
535
536 mutex_lock(&debug_mutex);
537 debug_info = file_inode(file)->i_private;
538 /* find debug view */
539 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
540 if (!debug_info->views[i])
541 continue;
542 else if (debug_info->debugfs_entries[i] == file->f_path.dentry)
543 goto found; /* found view ! */
544 }
545 /* no entry found */
546 rc = -EINVAL;
547 goto out;
548
549found:
550
551 /* Make snapshot of current debug areas to get it consistent. */
552 /* To copy all the areas is only needed, if we have a view which */
553 /* formats the debug areas. */
554
555 if (!debug_info->views[i]->format_proc && !debug_info->views[i]->header_proc)
556 debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
557 else
558 debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
559
560 if (!debug_info_snapshot) {
561 rc = -ENOMEM;
562 goto out;
563 }
564 p_info = kmalloc(sizeof(file_private_info_t), GFP_KERNEL);
565 if (!p_info) {
566 debug_info_free(debug_info_snapshot);
567 rc = -ENOMEM;
568 goto out;
569 }
570 p_info->offset = 0;
571 p_info->debug_info_snap = debug_info_snapshot;
572 p_info->debug_info_org = debug_info;
573 p_info->view = debug_info->views[i];
574 p_info->act_area = 0;
575 p_info->act_page = 0;
576 p_info->act_entry = DEBUG_PROLOG_ENTRY;
577 p_info->act_entry_offset = 0;
578 file->private_data = p_info;
579 debug_info_get(debug_info);
580 nonseekable_open(inode, file);
581out:
582 mutex_unlock(&debug_mutex);
583 return rc;
584}
585
586/*
587 * debug_close:
588 * - called for user close()
589 * - deletes private_data area of the file handle
590 */
591static int debug_close(struct inode *inode, struct file *file)
592{
593 file_private_info_t *p_info;
594
595 p_info = (file_private_info_t *) file->private_data;
596 if (p_info->debug_info_snap)
597 debug_info_free(p_info->debug_info_snap);
598 debug_info_put(p_info->debug_info_org);
599 kfree(file->private_data);
600 return 0; /* success */
601}
602
603/* Create debugfs entries and add to internal list. */
604static void _debug_register(debug_info_t *id)
605{
606 /* create root directory */
607 id->debugfs_root_entry = debugfs_create_dir(id->name,
608 debug_debugfs_root_entry);
609
610 /* append new element to linked list */
611 if (!debug_area_first) {
612 /* first element in list */
613 debug_area_first = id;
614 id->prev = NULL;
615 } else {
616 /* append element to end of list */
617 debug_area_last->next = id;
618 id->prev = debug_area_last;
619 }
620 debug_area_last = id;
621 id->next = NULL;
622
623 debug_register_view(id, &debug_level_view);
624 debug_register_view(id, &debug_flush_view);
625 debug_register_view(id, &debug_pages_view);
626}
627
628/**
629 * debug_register_mode() - creates and initializes debug area.
630 *
631 * @name: Name of debug log (e.g. used for debugfs entry)
632 * @pages_per_area: Number of pages, which will be allocated per area
633 * @nr_areas: Number of debug areas
634 * @buf_size: Size of data area in each debug entry
635 * @mode: File mode for debugfs files. E.g. S_IRWXUGO
636 * @uid: User ID for debugfs files. Currently only 0 is supported.
637 * @gid: Group ID for debugfs files. Currently only 0 is supported.
638 *
639 * Return:
640 * - Handle for generated debug area
641 * - %NULL if register failed
642 *
643 * Allocates memory for a debug log.
644 * Must not be called within an interrupt handler.
645 */
646debug_info_t *debug_register_mode(const char *name, int pages_per_area,
647 int nr_areas, int buf_size, umode_t mode,
648 uid_t uid, gid_t gid)
649{
650 debug_info_t *rc = NULL;
651
652 /* Since debugfs currently does not support uid/gid other than root, */
653 /* we do not allow gid/uid != 0 until we get support for that. */
654 if ((uid != 0) || (gid != 0))
655 pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
656 BUG_ON(!initialized);
657
658 /* create new debug_info */
659 rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
660 if (rc) {
661 mutex_lock(&debug_mutex);
662 _debug_register(rc);
663 mutex_unlock(&debug_mutex);
664 } else {
665 pr_err("Registering debug feature %s failed\n", name);
666 }
667 return rc;
668}
669EXPORT_SYMBOL(debug_register_mode);
670
671/**
672 * debug_register() - creates and initializes debug area with default file mode.
673 *
674 * @name: Name of debug log (e.g. used for debugfs entry)
675 * @pages_per_area: Number of pages, which will be allocated per area
676 * @nr_areas: Number of debug areas
677 * @buf_size: Size of data area in each debug entry
678 *
679 * Return:
680 * - Handle for generated debug area
681 * - %NULL if register failed
682 *
683 * Allocates memory for a debug log.
684 * The debugfs file mode access permissions are read and write for user.
685 * Must not be called within an interrupt handler.
686 */
687debug_info_t *debug_register(const char *name, int pages_per_area,
688 int nr_areas, int buf_size)
689{
690 return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
691 S_IRUSR | S_IWUSR, 0, 0);
692}
693EXPORT_SYMBOL(debug_register);
694
695/* Remove debugfs entries and remove from internal list. */
696static void _debug_unregister(debug_info_t *id)
697{
698 int i;
699
700 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
701 if (!id->views[i])
702 continue;
703 debugfs_remove(id->debugfs_entries[i]);
704 }
705 debugfs_remove(id->debugfs_root_entry);
706 if (id == debug_area_first)
707 debug_area_first = id->next;
708 if (id == debug_area_last)
709 debug_area_last = id->prev;
710 if (id->prev)
711 id->prev->next = id->next;
712 if (id->next)
713 id->next->prev = id->prev;
714}
715
716/**
717 * debug_unregister() - give back debug area.
718 *
719 * @id: handle for debug log
720 *
721 * Return:
722 * none
723 */
724void debug_unregister(debug_info_t *id)
725{
726 if (!id)
727 return;
728 mutex_lock(&debug_mutex);
729 _debug_unregister(id);
730 mutex_unlock(&debug_mutex);
731
732 debug_info_put(id);
733}
734EXPORT_SYMBOL(debug_unregister);
735
736/*
737 * debug_set_size:
738 * - set area size (number of pages) and number of areas
739 */
740static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
741{
742 debug_info_t *new_id;
743 unsigned long flags;
744
745 if (!id || (nr_areas <= 0) || (pages_per_area < 0))
746 return -EINVAL;
747
748 new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
749 id->level, ALL_AREAS);
750 if (!new_id) {
751 pr_info("Allocating memory for %i pages failed\n",
752 pages_per_area);
753 return -ENOMEM;
754 }
755
756 spin_lock_irqsave(&id->lock, flags);
757 debug_events_append(new_id, id);
758 debug_areas_swap(new_id, id);
759 debug_info_free(new_id);
760 spin_unlock_irqrestore(&id->lock, flags);
761 pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
762
763 return 0;
764}
765
766/**
767 * debug_set_level() - Sets new actual debug level if new_level is valid.
768 *
769 * @id: handle for debug log
770 * @new_level: new debug level
771 *
772 * Return:
773 * none
774 */
775void debug_set_level(debug_info_t *id, int new_level)
776{
777 unsigned long flags;
778
779 if (!id)
780 return;
781 spin_lock_irqsave(&id->lock, flags);
782 if (new_level == DEBUG_OFF_LEVEL) {
783 id->level = DEBUG_OFF_LEVEL;
784 pr_info("%s: switched off\n", id->name);
785 } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
786 pr_info("%s: level %i is out of range (%i - %i)\n",
787 id->name, new_level, 0, DEBUG_MAX_LEVEL);
788 } else {
789 id->level = new_level;
790 }
791 spin_unlock_irqrestore(&id->lock, flags);
792}
793EXPORT_SYMBOL(debug_set_level);
794
795/*
796 * proceed_active_entry:
797 * - set active entry to next in the ring buffer
798 */
799static inline void proceed_active_entry(debug_info_t *id)
800{
801 if ((id->active_entries[id->active_area] += id->entry_size)
802 > (PAGE_SIZE - id->entry_size)) {
803 id->active_entries[id->active_area] = 0;
804 id->active_pages[id->active_area] =
805 (id->active_pages[id->active_area] + 1) %
806 id->pages_per_area;
807 }
808}
809
810/*
811 * proceed_active_area:
812 * - set active area to next in the ring buffer
813 */
814static inline void proceed_active_area(debug_info_t *id)
815{
816 id->active_area++;
817 id->active_area = id->active_area % id->nr_areas;
818}
819
820/*
821 * get_active_entry:
822 */
823static inline debug_entry_t *get_active_entry(debug_info_t *id)
824{
825 return (debug_entry_t *) (((char *) id->areas[id->active_area]
826 [id->active_pages[id->active_area]]) +
827 id->active_entries[id->active_area]);
828}
829
830/* Swap debug areas of a and b. */
831static void debug_areas_swap(debug_info_t *a, debug_info_t *b)
832{
833 swap(a->nr_areas, b->nr_areas);
834 swap(a->pages_per_area, b->pages_per_area);
835 swap(a->areas, b->areas);
836 swap(a->active_area, b->active_area);
837 swap(a->active_pages, b->active_pages);
838 swap(a->active_entries, b->active_entries);
839}
840
841/* Append all debug events in active area from source to destination log. */
842static void debug_events_append(debug_info_t *dest, debug_info_t *src)
843{
844 debug_entry_t *from, *to, *last;
845
846 if (!src->areas || !dest->areas)
847 return;
848
849 /* Loop over all entries in src, starting with oldest. */
850 from = get_active_entry(src);
851 last = from;
852 do {
853 if (from->clock != 0LL) {
854 to = get_active_entry(dest);
855 memset(to, 0, dest->entry_size);
856 memcpy(to, from, min(src->entry_size,
857 dest->entry_size));
858 proceed_active_entry(dest);
859 }
860
861 proceed_active_entry(src);
862 from = get_active_entry(src);
863 } while (from != last);
864}
865
866/*
867 * debug_finish_entry:
868 * - set timestamp, caller address, cpu number etc.
869 */
870
871static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
872 int level, int exception)
873{
874 unsigned long timestamp;
875 union tod_clock clk;
876
877 store_tod_clock_ext(&clk);
878 timestamp = clk.us;
879 timestamp -= TOD_UNIX_EPOCH >> 12;
880 active->clock = timestamp;
881 active->cpu = smp_processor_id();
882 active->caller = __builtin_return_address(0);
883 active->exception = exception;
884 active->level = level;
885 proceed_active_entry(id);
886 if (exception)
887 proceed_active_area(id);
888}
889
890static int debug_stoppable = 1;
891static int debug_active = 1;
892
893#define CTL_S390DBF_STOPPABLE 5678
894#define CTL_S390DBF_ACTIVE 5679
895
896/*
897 * proc handler for the running debug_active sysctl
898 * always allow read, allow write only if debug_stoppable is set or
899 * if debug_active is already off
900 */
901static int s390dbf_procactive(struct ctl_table *table, int write,
902 void *buffer, size_t *lenp, loff_t *ppos)
903{
904 if (!write || debug_stoppable || !debug_active)
905 return proc_dointvec(table, write, buffer, lenp, ppos);
906 else
907 return 0;
908}
909
910static struct ctl_table s390dbf_table[] = {
911 {
912 .procname = "debug_stoppable",
913 .data = &debug_stoppable,
914 .maxlen = sizeof(int),
915 .mode = S_IRUGO | S_IWUSR,
916 .proc_handler = proc_dointvec,
917 },
918 {
919 .procname = "debug_active",
920 .data = &debug_active,
921 .maxlen = sizeof(int),
922 .mode = S_IRUGO | S_IWUSR,
923 .proc_handler = s390dbf_procactive,
924 },
925 { }
926};
927
928static struct ctl_table s390dbf_dir_table[] = {
929 {
930 .procname = "s390dbf",
931 .maxlen = 0,
932 .mode = S_IRUGO | S_IXUGO,
933 .child = s390dbf_table,
934 },
935 { }
936};
937
938static struct ctl_table_header *s390dbf_sysctl_header;
939
940/**
941 * debug_stop_all() - stops the debug feature if stopping is allowed.
942 *
943 * Return:
944 * - none
945 *
946 * Currently used in case of a kernel oops.
947 */
948void debug_stop_all(void)
949{
950 if (debug_stoppable)
951 debug_active = 0;
952}
953EXPORT_SYMBOL(debug_stop_all);
954
955/**
956 * debug_set_critical() - event/exception functions try lock instead of spin.
957 *
958 * Return:
959 * - none
960 *
961 * Currently used in case of stopping all CPUs but the current one.
962 * Once in this state, functions to write a debug entry for an
963 * event or exception no longer spin on the debug area lock,
964 * but only try to get it and fail if they do not get the lock.
965 */
966void debug_set_critical(void)
967{
968 debug_critical = 1;
969}
970
971/*
972 * debug_event_common:
973 * - write debug entry with given size
974 */
975debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
976 int len)
977{
978 debug_entry_t *active;
979 unsigned long flags;
980
981 if (!debug_active || !id->areas)
982 return NULL;
983 if (debug_critical) {
984 if (!spin_trylock_irqsave(&id->lock, flags))
985 return NULL;
986 } else {
987 spin_lock_irqsave(&id->lock, flags);
988 }
989 do {
990 active = get_active_entry(id);
991 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
992 if (len < id->buf_size)
993 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
994 debug_finish_entry(id, active, level, 0);
995 len -= id->buf_size;
996 buf += id->buf_size;
997 } while (len > 0);
998
999 spin_unlock_irqrestore(&id->lock, flags);
1000 return active;
1001}
1002EXPORT_SYMBOL(debug_event_common);
1003
1004/*
1005 * debug_exception_common:
1006 * - write debug entry with given size and switch to next debug area
1007 */
1008debug_entry_t *debug_exception_common(debug_info_t *id, int level,
1009 const void *buf, int len)
1010{
1011 debug_entry_t *active;
1012 unsigned long flags;
1013
1014 if (!debug_active || !id->areas)
1015 return NULL;
1016 if (debug_critical) {
1017 if (!spin_trylock_irqsave(&id->lock, flags))
1018 return NULL;
1019 } else {
1020 spin_lock_irqsave(&id->lock, flags);
1021 }
1022 do {
1023 active = get_active_entry(id);
1024 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1025 if (len < id->buf_size)
1026 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1027 debug_finish_entry(id, active, level, len <= id->buf_size);
1028 len -= id->buf_size;
1029 buf += id->buf_size;
1030 } while (len > 0);
1031
1032 spin_unlock_irqrestore(&id->lock, flags);
1033 return active;
1034}
1035EXPORT_SYMBOL(debug_exception_common);
1036
1037/*
1038 * counts arguments in format string for sprintf view
1039 */
1040static inline int debug_count_numargs(char *string)
1041{
1042 int numargs = 0;
1043
1044 while (*string) {
1045 if (*string++ == '%')
1046 numargs++;
1047 }
1048 return numargs;
1049}
1050
1051/*
1052 * debug_sprintf_event:
1053 */
1054debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
1055{
1056 debug_sprintf_entry_t *curr_event;
1057 debug_entry_t *active;
1058 unsigned long flags;
1059 int numargs, idx;
1060 va_list ap;
1061
1062 if (!debug_active || !id->areas)
1063 return NULL;
1064 numargs = debug_count_numargs(string);
1065
1066 if (debug_critical) {
1067 if (!spin_trylock_irqsave(&id->lock, flags))
1068 return NULL;
1069 } else {
1070 spin_lock_irqsave(&id->lock, flags);
1071 }
1072 active = get_active_entry(id);
1073 curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
1074 va_start(ap, string);
1075 curr_event->string = string;
1076 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1077 curr_event->args[idx] = va_arg(ap, long);
1078 va_end(ap);
1079 debug_finish_entry(id, active, level, 0);
1080 spin_unlock_irqrestore(&id->lock, flags);
1081
1082 return active;
1083}
1084EXPORT_SYMBOL(__debug_sprintf_event);
1085
1086/*
1087 * debug_sprintf_exception:
1088 */
1089debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1090{
1091 debug_sprintf_entry_t *curr_event;
1092 debug_entry_t *active;
1093 unsigned long flags;
1094 int numargs, idx;
1095 va_list ap;
1096
1097 if (!debug_active || !id->areas)
1098 return NULL;
1099
1100 numargs = debug_count_numargs(string);
1101
1102 if (debug_critical) {
1103 if (!spin_trylock_irqsave(&id->lock, flags))
1104 return NULL;
1105 } else {
1106 spin_lock_irqsave(&id->lock, flags);
1107 }
1108 active = get_active_entry(id);
1109 curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
1110 va_start(ap, string);
1111 curr_event->string = string;
1112 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1113 curr_event->args[idx] = va_arg(ap, long);
1114 va_end(ap);
1115 debug_finish_entry(id, active, level, 1);
1116 spin_unlock_irqrestore(&id->lock, flags);
1117
1118 return active;
1119}
1120EXPORT_SYMBOL(__debug_sprintf_exception);
1121
1122/**
1123 * debug_register_view() - registers new debug view and creates debugfs
1124 * dir entry
1125 *
1126 * @id: handle for debug log
1127 * @view: pointer to debug view struct
1128 *
1129 * Return:
1130 * - 0 : ok
1131 * - < 0: Error
1132 */
1133int debug_register_view(debug_info_t *id, struct debug_view *view)
1134{
1135 unsigned long flags;
1136 struct dentry *pde;
1137 umode_t mode;
1138 int rc = 0;
1139 int i;
1140
1141 if (!id)
1142 goto out;
1143 mode = (id->mode | S_IFREG) & ~S_IXUGO;
1144 if (!(view->prolog_proc || view->format_proc || view->header_proc))
1145 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1146 if (!view->input_proc)
1147 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1148 pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1149 id, &debug_file_ops);
1150 spin_lock_irqsave(&id->lock, flags);
1151 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1152 if (!id->views[i])
1153 break;
1154 }
1155 if (i == DEBUG_MAX_VIEWS) {
1156 pr_err("Registering view %s/%s would exceed the maximum "
1157 "number of views %i\n", id->name, view->name, i);
1158 rc = -1;
1159 } else {
1160 id->views[i] = view;
1161 id->debugfs_entries[i] = pde;
1162 }
1163 spin_unlock_irqrestore(&id->lock, flags);
1164 if (rc)
1165 debugfs_remove(pde);
1166out:
1167 return rc;
1168}
1169EXPORT_SYMBOL(debug_register_view);
1170
1171/**
1172 * debug_unregister_view() - unregisters debug view and removes debugfs
1173 * dir entry
1174 *
1175 * @id: handle for debug log
1176 * @view: pointer to debug view struct
1177 *
1178 * Return:
1179 * - 0 : ok
1180 * - < 0: Error
1181 */
1182int debug_unregister_view(debug_info_t *id, struct debug_view *view)
1183{
1184 struct dentry *dentry = NULL;
1185 unsigned long flags;
1186 int i, rc = 0;
1187
1188 if (!id)
1189 goto out;
1190 spin_lock_irqsave(&id->lock, flags);
1191 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1192 if (id->views[i] == view)
1193 break;
1194 }
1195 if (i == DEBUG_MAX_VIEWS) {
1196 rc = -1;
1197 } else {
1198 dentry = id->debugfs_entries[i];
1199 id->views[i] = NULL;
1200 id->debugfs_entries[i] = NULL;
1201 }
1202 spin_unlock_irqrestore(&id->lock, flags);
1203 debugfs_remove(dentry);
1204out:
1205 return rc;
1206}
1207EXPORT_SYMBOL(debug_unregister_view);
1208
1209static inline char *debug_get_user_string(const char __user *user_buf,
1210 size_t user_len)
1211{
1212 char *buffer;
1213
1214 buffer = kmalloc(user_len + 1, GFP_KERNEL);
1215 if (!buffer)
1216 return ERR_PTR(-ENOMEM);
1217 if (copy_from_user(buffer, user_buf, user_len) != 0) {
1218 kfree(buffer);
1219 return ERR_PTR(-EFAULT);
1220 }
1221 /* got the string, now strip linefeed. */
1222 if (buffer[user_len - 1] == '\n')
1223 buffer[user_len - 1] = 0;
1224 else
1225 buffer[user_len] = 0;
1226 return buffer;
1227}
1228
1229static inline int debug_get_uint(char *buf)
1230{
1231 int rc;
1232
1233 buf = skip_spaces(buf);
1234 rc = simple_strtoul(buf, &buf, 10);
1235 if (*buf)
1236 rc = -EINVAL;
1237 return rc;
1238}
1239
1240/*
1241 * functions for debug-views
1242 ***********************************
1243*/
1244
1245/*
1246 * prints out actual debug level
1247 */
1248
1249static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
1250 char *out_buf)
1251{
1252 return sprintf(out_buf, "%i\n", id->pages_per_area);
1253}
1254
1255/*
1256 * reads new size (number of pages per debug area)
1257 */
1258
1259static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
1260 struct file *file, const char __user *user_buf,
1261 size_t user_len, loff_t *offset)
1262{
1263 int rc, new_pages;
1264 char *str;
1265
1266 if (user_len > 0x10000)
1267 user_len = 0x10000;
1268 if (*offset != 0) {
1269 rc = -EPIPE;
1270 goto out;
1271 }
1272 str = debug_get_user_string(user_buf, user_len);
1273 if (IS_ERR(str)) {
1274 rc = PTR_ERR(str);
1275 goto out;
1276 }
1277 new_pages = debug_get_uint(str);
1278 if (new_pages < 0) {
1279 rc = -EINVAL;
1280 goto free_str;
1281 }
1282 rc = debug_set_size(id, id->nr_areas, new_pages);
1283 if (rc != 0) {
1284 rc = -EINVAL;
1285 goto free_str;
1286 }
1287 rc = user_len;
1288free_str:
1289 kfree(str);
1290out:
1291 *offset += user_len;
1292 return rc; /* number of input characters */
1293}
1294
1295/*
1296 * prints out actual debug level
1297 */
1298static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
1299 char *out_buf)
1300{
1301 int rc = 0;
1302
1303 if (id->level == DEBUG_OFF_LEVEL)
1304 rc = sprintf(out_buf, "-\n");
1305 else
1306 rc = sprintf(out_buf, "%i\n", id->level);
1307 return rc;
1308}
1309
1310/*
1311 * reads new debug level
1312 */
1313static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
1314 struct file *file, const char __user *user_buf,
1315 size_t user_len, loff_t *offset)
1316{
1317 int rc, new_level;
1318 char *str;
1319
1320 if (user_len > 0x10000)
1321 user_len = 0x10000;
1322 if (*offset != 0) {
1323 rc = -EPIPE;
1324 goto out;
1325 }
1326 str = debug_get_user_string(user_buf, user_len);
1327 if (IS_ERR(str)) {
1328 rc = PTR_ERR(str);
1329 goto out;
1330 }
1331 if (str[0] == '-') {
1332 debug_set_level(id, DEBUG_OFF_LEVEL);
1333 rc = user_len;
1334 goto free_str;
1335 } else {
1336 new_level = debug_get_uint(str);
1337 }
1338 if (new_level < 0) {
1339 pr_warn("%s is not a valid level for a debug feature\n", str);
1340 rc = -EINVAL;
1341 } else {
1342 debug_set_level(id, new_level);
1343 rc = user_len;
1344 }
1345free_str:
1346 kfree(str);
1347out:
1348 *offset += user_len;
1349 return rc; /* number of input characters */
1350}
1351
1352/*
1353 * flushes debug areas
1354 */
1355static void debug_flush(debug_info_t *id, int area)
1356{
1357 unsigned long flags;
1358 int i, j;
1359
1360 if (!id || !id->areas)
1361 return;
1362 spin_lock_irqsave(&id->lock, flags);
1363 if (area == DEBUG_FLUSH_ALL) {
1364 id->active_area = 0;
1365 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1366 for (i = 0; i < id->nr_areas; i++) {
1367 id->active_pages[i] = 0;
1368 for (j = 0; j < id->pages_per_area; j++)
1369 memset(id->areas[i][j], 0, PAGE_SIZE);
1370 }
1371 } else if (area >= 0 && area < id->nr_areas) {
1372 id->active_entries[area] = 0;
1373 id->active_pages[area] = 0;
1374 for (i = 0; i < id->pages_per_area; i++)
1375 memset(id->areas[area][i], 0, PAGE_SIZE);
1376 }
1377 spin_unlock_irqrestore(&id->lock, flags);
1378}
1379
1380/*
1381 * view function: flushes debug areas
1382 */
1383static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
1384 struct file *file, const char __user *user_buf,
1385 size_t user_len, loff_t *offset)
1386{
1387 char input_buf[1];
1388 int rc = user_len;
1389
1390 if (user_len > 0x10000)
1391 user_len = 0x10000;
1392 if (*offset != 0) {
1393 rc = -EPIPE;
1394 goto out;
1395 }
1396 if (copy_from_user(input_buf, user_buf, 1)) {
1397 rc = -EFAULT;
1398 goto out;
1399 }
1400 if (input_buf[0] == '-') {
1401 debug_flush(id, DEBUG_FLUSH_ALL);
1402 goto out;
1403 }
1404 if (isdigit(input_buf[0])) {
1405 int area = ((int) input_buf[0] - (int) '0');
1406
1407 debug_flush(id, area);
1408 goto out;
1409 }
1410
1411 pr_info("Flushing debug data failed because %c is not a valid "
1412 "area\n", input_buf[0]);
1413
1414out:
1415 *offset += user_len;
1416 return rc; /* number of input characters */
1417}
1418
1419/*
1420 * prints debug data in hex/ascii format
1421 */
1422static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
1423 char *out_buf, const char *in_buf)
1424{
1425 int i, rc = 0;
1426
1427 for (i = 0; i < id->buf_size; i++)
1428 rc += sprintf(out_buf + rc, "%02x ", ((unsigned char *) in_buf)[i]);
1429 rc += sprintf(out_buf + rc, "| ");
1430 for (i = 0; i < id->buf_size; i++) {
1431 unsigned char c = in_buf[i];
1432
1433 if (isascii(c) && isprint(c))
1434 rc += sprintf(out_buf + rc, "%c", c);
1435 else
1436 rc += sprintf(out_buf + rc, ".");
1437 }
1438 rc += sprintf(out_buf + rc, "\n");
1439 return rc;
1440}
1441
1442/*
1443 * prints header for debug entry
1444 */
1445int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
1446 int area, debug_entry_t *entry, char *out_buf)
1447{
1448 unsigned long sec, usec;
1449 unsigned long caller;
1450 unsigned int level;
1451 char *except_str;
1452 int rc = 0;
1453
1454 level = entry->level;
1455 sec = entry->clock;
1456 usec = do_div(sec, USEC_PER_SEC);
1457
1458 if (entry->exception)
1459 except_str = "*";
1460 else
1461 except_str = "-";
1462 caller = (unsigned long) entry->caller;
1463 rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %04u %px ",
1464 area, sec, usec, level, except_str,
1465 entry->cpu, (void *)caller);
1466 return rc;
1467}
1468EXPORT_SYMBOL(debug_dflt_header_fn);
1469
1470/*
1471 * prints debug data sprintf-formated:
1472 * debug_sprinf_event/exception calls must be used together with this view
1473 */
1474
1475#define DEBUG_SPRINTF_MAX_ARGS 10
1476
1477static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
1478 char *out_buf, debug_sprintf_entry_t *curr_event)
1479{
1480 int num_longs, num_used_args = 0, i, rc = 0;
1481 int index[DEBUG_SPRINTF_MAX_ARGS];
1482
1483 /* count of longs fit into one entry */
1484 num_longs = id->buf_size / sizeof(long);
1485
1486 if (num_longs < 1)
1487 goto out; /* bufsize of entry too small */
1488 if (num_longs == 1) {
1489 /* no args, we use only the string */
1490 strcpy(out_buf, curr_event->string);
1491 rc = strlen(curr_event->string);
1492 goto out;
1493 }
1494
1495 /* number of arguments used for sprintf (without the format string) */
1496 num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1497
1498 memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1499
1500 for (i = 0; i < num_used_args; i++)
1501 index[i] = i;
1502
1503 rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1504 curr_event->args[index[1]], curr_event->args[index[2]],
1505 curr_event->args[index[3]], curr_event->args[index[4]],
1506 curr_event->args[index[5]], curr_event->args[index[6]],
1507 curr_event->args[index[7]], curr_event->args[index[8]],
1508 curr_event->args[index[9]]);
1509out:
1510 return rc;
1511}
1512
1513/*
1514 * debug_init:
1515 * - is called exactly once to initialize the debug feature
1516 */
1517static int __init debug_init(void)
1518{
1519 s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
1520 mutex_lock(&debug_mutex);
1521 debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1522 initialized = 1;
1523 mutex_unlock(&debug_mutex);
1524 return 0;
1525}
1526postcore_initcall(debug_init);