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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * S/390 debug facility
4 *
5 * Copyright IBM Corp. 1999, 2020
6 *
7 * Author(s): Michael Holzheu (holzheu@de.ibm.com),
8 * Holger Smolinski (Holger.Smolinski@de.ibm.com)
9 *
10 * Bugreports to: <Linux390@de.ibm.com>
11 */
12
13#define KMSG_COMPONENT "s390dbf"
14#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
15
16#include <linux/stddef.h>
17#include <linux/kernel.h>
18#include <linux/errno.h>
19#include <linux/slab.h>
20#include <linux/ctype.h>
21#include <linux/string.h>
22#include <linux/sysctl.h>
23#include <linux/uaccess.h>
24#include <linux/export.h>
25#include <linux/init.h>
26#include <linux/fs.h>
27#include <linux/minmax.h>
28#include <linux/debugfs.h>
29
30#include <asm/debug.h>
31
32#define DEBUG_PROLOG_ENTRY -1
33
34#define ALL_AREAS 0 /* copy all debug areas */
35#define NO_AREAS 1 /* copy no debug areas */
36
37/* typedefs */
38
39typedef struct file_private_info {
40 loff_t offset; /* offset of last read in file */
41 int act_area; /* number of last 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, const char *inbuf);
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_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 strscpy(rc->name, name, sizeof(rc->name));
254 memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
255 memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
256 refcount_set(&(rc->ref_count), 0);
257
258 return rc;
259
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/**
696 * debug_register_static() - registers a static debug area
697 *
698 * @id: Handle for static debug area
699 * @pages_per_area: Number of pages per area
700 * @nr_areas: Number of debug areas
701 *
702 * Register debug_info_t defined using DEFINE_STATIC_DEBUG_INFO.
703 *
704 * Note: This function is called automatically via an initcall generated by
705 * DEFINE_STATIC_DEBUG_INFO.
706 */
707void debug_register_static(debug_info_t *id, int pages_per_area, int nr_areas)
708{
709 unsigned long flags;
710 debug_info_t *copy;
711
712 if (!initialized) {
713 pr_err("Tried to register debug feature %s too early\n",
714 id->name);
715 return;
716 }
717
718 copy = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
719 id->level, ALL_AREAS);
720 if (!copy) {
721 pr_err("Registering debug feature %s failed\n", id->name);
722
723 /* Clear pointers to prevent tracing into released initdata. */
724 spin_lock_irqsave(&id->lock, flags);
725 id->areas = NULL;
726 id->active_pages = NULL;
727 id->active_entries = NULL;
728 spin_unlock_irqrestore(&id->lock, flags);
729
730 return;
731 }
732
733 /* Replace static trace area with dynamic copy. */
734 spin_lock_irqsave(&id->lock, flags);
735 debug_events_append(copy, id);
736 debug_areas_swap(id, copy);
737 spin_unlock_irqrestore(&id->lock, flags);
738
739 /* Clear pointers to initdata and discard copy. */
740 copy->areas = NULL;
741 copy->active_pages = NULL;
742 copy->active_entries = NULL;
743 debug_info_free(copy);
744
745 mutex_lock(&debug_mutex);
746 _debug_register(id);
747 mutex_unlock(&debug_mutex);
748}
749
750/* Remove debugfs entries and remove from internal list. */
751static void _debug_unregister(debug_info_t *id)
752{
753 int i;
754
755 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
756 if (!id->views[i])
757 continue;
758 debugfs_remove(id->debugfs_entries[i]);
759 }
760 debugfs_remove(id->debugfs_root_entry);
761 if (id == debug_area_first)
762 debug_area_first = id->next;
763 if (id == debug_area_last)
764 debug_area_last = id->prev;
765 if (id->prev)
766 id->prev->next = id->next;
767 if (id->next)
768 id->next->prev = id->prev;
769}
770
771/**
772 * debug_unregister() - give back debug area.
773 *
774 * @id: handle for debug log
775 *
776 * Return:
777 * none
778 */
779void debug_unregister(debug_info_t *id)
780{
781 if (!id)
782 return;
783 mutex_lock(&debug_mutex);
784 _debug_unregister(id);
785 mutex_unlock(&debug_mutex);
786
787 debug_info_put(id);
788}
789EXPORT_SYMBOL(debug_unregister);
790
791/*
792 * debug_set_size:
793 * - set area size (number of pages) and number of areas
794 */
795static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
796{
797 debug_info_t *new_id;
798 unsigned long flags;
799
800 if (!id || (nr_areas <= 0) || (pages_per_area < 0))
801 return -EINVAL;
802
803 new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
804 id->level, ALL_AREAS);
805 if (!new_id) {
806 pr_info("Allocating memory for %i pages failed\n",
807 pages_per_area);
808 return -ENOMEM;
809 }
810
811 spin_lock_irqsave(&id->lock, flags);
812 debug_events_append(new_id, id);
813 debug_areas_swap(new_id, id);
814 debug_info_free(new_id);
815 spin_unlock_irqrestore(&id->lock, flags);
816 pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
817
818 return 0;
819}
820
821/**
822 * debug_set_level() - Sets new actual debug level if new_level is valid.
823 *
824 * @id: handle for debug log
825 * @new_level: new debug level
826 *
827 * Return:
828 * none
829 */
830void debug_set_level(debug_info_t *id, int new_level)
831{
832 unsigned long flags;
833
834 if (!id)
835 return;
836
837 if (new_level == DEBUG_OFF_LEVEL) {
838 pr_info("%s: switched off\n", id->name);
839 } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
840 pr_info("%s: level %i is out of range (%i - %i)\n",
841 id->name, new_level, 0, DEBUG_MAX_LEVEL);
842 return;
843 }
844
845 spin_lock_irqsave(&id->lock, flags);
846 id->level = new_level;
847 spin_unlock_irqrestore(&id->lock, flags);
848}
849EXPORT_SYMBOL(debug_set_level);
850
851/*
852 * proceed_active_entry:
853 * - set active entry to next in the ring buffer
854 */
855static inline void proceed_active_entry(debug_info_t *id)
856{
857 if ((id->active_entries[id->active_area] += id->entry_size)
858 > (PAGE_SIZE - id->entry_size)) {
859 id->active_entries[id->active_area] = 0;
860 id->active_pages[id->active_area] =
861 (id->active_pages[id->active_area] + 1) %
862 id->pages_per_area;
863 }
864}
865
866/*
867 * proceed_active_area:
868 * - set active area to next in the ring buffer
869 */
870static inline void proceed_active_area(debug_info_t *id)
871{
872 id->active_area++;
873 id->active_area = id->active_area % id->nr_areas;
874}
875
876/*
877 * get_active_entry:
878 */
879static inline debug_entry_t *get_active_entry(debug_info_t *id)
880{
881 return (debug_entry_t *) (((char *) id->areas[id->active_area]
882 [id->active_pages[id->active_area]]) +
883 id->active_entries[id->active_area]);
884}
885
886/* Swap debug areas of a and b. */
887static void debug_areas_swap(debug_info_t *a, debug_info_t *b)
888{
889 swap(a->nr_areas, b->nr_areas);
890 swap(a->pages_per_area, b->pages_per_area);
891 swap(a->areas, b->areas);
892 swap(a->active_area, b->active_area);
893 swap(a->active_pages, b->active_pages);
894 swap(a->active_entries, b->active_entries);
895}
896
897/* Append all debug events in active area from source to destination log. */
898static void debug_events_append(debug_info_t *dest, debug_info_t *src)
899{
900 debug_entry_t *from, *to, *last;
901
902 if (!src->areas || !dest->areas)
903 return;
904
905 /* Loop over all entries in src, starting with oldest. */
906 from = get_active_entry(src);
907 last = from;
908 do {
909 if (from->clock != 0LL) {
910 to = get_active_entry(dest);
911 memset(to, 0, dest->entry_size);
912 memcpy(to, from, min(src->entry_size,
913 dest->entry_size));
914 proceed_active_entry(dest);
915 }
916
917 proceed_active_entry(src);
918 from = get_active_entry(src);
919 } while (from != last);
920}
921
922/*
923 * debug_finish_entry:
924 * - set timestamp, caller address, cpu number etc.
925 */
926
927static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
928 int level, int exception)
929{
930 unsigned long timestamp;
931 union tod_clock clk;
932
933 store_tod_clock_ext(&clk);
934 timestamp = clk.us;
935 timestamp -= TOD_UNIX_EPOCH >> 12;
936 active->clock = timestamp;
937 active->cpu = smp_processor_id();
938 active->caller = __builtin_return_address(0);
939 active->exception = exception;
940 active->level = level;
941 proceed_active_entry(id);
942 if (exception)
943 proceed_active_area(id);
944}
945
946static int debug_stoppable = 1;
947static int debug_active = 1;
948
949#define CTL_S390DBF_STOPPABLE 5678
950#define CTL_S390DBF_ACTIVE 5679
951
952/*
953 * proc handler for the running debug_active sysctl
954 * always allow read, allow write only if debug_stoppable is set or
955 * if debug_active is already off
956 */
957static int s390dbf_procactive(struct ctl_table *table, int write,
958 void *buffer, size_t *lenp, loff_t *ppos)
959{
960 if (!write || debug_stoppable || !debug_active)
961 return proc_dointvec(table, write, buffer, lenp, ppos);
962 else
963 return 0;
964}
965
966static struct ctl_table s390dbf_table[] = {
967 {
968 .procname = "debug_stoppable",
969 .data = &debug_stoppable,
970 .maxlen = sizeof(int),
971 .mode = S_IRUGO | S_IWUSR,
972 .proc_handler = proc_dointvec,
973 },
974 {
975 .procname = "debug_active",
976 .data = &debug_active,
977 .maxlen = sizeof(int),
978 .mode = S_IRUGO | S_IWUSR,
979 .proc_handler = s390dbf_procactive,
980 },
981 { }
982};
983
984static struct ctl_table s390dbf_dir_table[] = {
985 {
986 .procname = "s390dbf",
987 .maxlen = 0,
988 .mode = S_IRUGO | S_IXUGO,
989 .child = s390dbf_table,
990 },
991 { }
992};
993
994static struct ctl_table_header *s390dbf_sysctl_header;
995
996/**
997 * debug_stop_all() - stops the debug feature if stopping is allowed.
998 *
999 * Return:
1000 * - none
1001 *
1002 * Currently used in case of a kernel oops.
1003 */
1004void debug_stop_all(void)
1005{
1006 if (debug_stoppable)
1007 debug_active = 0;
1008}
1009EXPORT_SYMBOL(debug_stop_all);
1010
1011/**
1012 * debug_set_critical() - event/exception functions try lock instead of spin.
1013 *
1014 * Return:
1015 * - none
1016 *
1017 * Currently used in case of stopping all CPUs but the current one.
1018 * Once in this state, functions to write a debug entry for an
1019 * event or exception no longer spin on the debug area lock,
1020 * but only try to get it and fail if they do not get the lock.
1021 */
1022void debug_set_critical(void)
1023{
1024 debug_critical = 1;
1025}
1026
1027/*
1028 * debug_event_common:
1029 * - write debug entry with given size
1030 */
1031debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
1032 int len)
1033{
1034 debug_entry_t *active;
1035 unsigned long flags;
1036
1037 if (!debug_active || !id->areas)
1038 return NULL;
1039 if (debug_critical) {
1040 if (!spin_trylock_irqsave(&id->lock, flags))
1041 return NULL;
1042 } else {
1043 spin_lock_irqsave(&id->lock, flags);
1044 }
1045 do {
1046 active = get_active_entry(id);
1047 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1048 if (len < id->buf_size)
1049 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1050 debug_finish_entry(id, active, level, 0);
1051 len -= id->buf_size;
1052 buf += id->buf_size;
1053 } while (len > 0);
1054
1055 spin_unlock_irqrestore(&id->lock, flags);
1056 return active;
1057}
1058EXPORT_SYMBOL(debug_event_common);
1059
1060/*
1061 * debug_exception_common:
1062 * - write debug entry with given size and switch to next debug area
1063 */
1064debug_entry_t *debug_exception_common(debug_info_t *id, int level,
1065 const void *buf, int len)
1066{
1067 debug_entry_t *active;
1068 unsigned long flags;
1069
1070 if (!debug_active || !id->areas)
1071 return NULL;
1072 if (debug_critical) {
1073 if (!spin_trylock_irqsave(&id->lock, flags))
1074 return NULL;
1075 } else {
1076 spin_lock_irqsave(&id->lock, flags);
1077 }
1078 do {
1079 active = get_active_entry(id);
1080 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
1081 if (len < id->buf_size)
1082 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
1083 debug_finish_entry(id, active, level, len <= id->buf_size);
1084 len -= id->buf_size;
1085 buf += id->buf_size;
1086 } while (len > 0);
1087
1088 spin_unlock_irqrestore(&id->lock, flags);
1089 return active;
1090}
1091EXPORT_SYMBOL(debug_exception_common);
1092
1093/*
1094 * counts arguments in format string for sprintf view
1095 */
1096static inline int debug_count_numargs(char *string)
1097{
1098 int numargs = 0;
1099
1100 while (*string) {
1101 if (*string++ == '%')
1102 numargs++;
1103 }
1104 return numargs;
1105}
1106
1107/*
1108 * debug_sprintf_event:
1109 */
1110debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
1111{
1112 debug_sprintf_entry_t *curr_event;
1113 debug_entry_t *active;
1114 unsigned long flags;
1115 int numargs, idx;
1116 va_list ap;
1117
1118 if (!debug_active || !id->areas)
1119 return NULL;
1120 numargs = debug_count_numargs(string);
1121
1122 if (debug_critical) {
1123 if (!spin_trylock_irqsave(&id->lock, flags))
1124 return NULL;
1125 } else {
1126 spin_lock_irqsave(&id->lock, flags);
1127 }
1128 active = get_active_entry(id);
1129 curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
1130 va_start(ap, string);
1131 curr_event->string = string;
1132 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1133 curr_event->args[idx] = va_arg(ap, long);
1134 va_end(ap);
1135 debug_finish_entry(id, active, level, 0);
1136 spin_unlock_irqrestore(&id->lock, flags);
1137
1138 return active;
1139}
1140EXPORT_SYMBOL(__debug_sprintf_event);
1141
1142/*
1143 * debug_sprintf_exception:
1144 */
1145debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1146{
1147 debug_sprintf_entry_t *curr_event;
1148 debug_entry_t *active;
1149 unsigned long flags;
1150 int numargs, idx;
1151 va_list ap;
1152
1153 if (!debug_active || !id->areas)
1154 return NULL;
1155
1156 numargs = debug_count_numargs(string);
1157
1158 if (debug_critical) {
1159 if (!spin_trylock_irqsave(&id->lock, flags))
1160 return NULL;
1161 } else {
1162 spin_lock_irqsave(&id->lock, flags);
1163 }
1164 active = get_active_entry(id);
1165 curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
1166 va_start(ap, string);
1167 curr_event->string = string;
1168 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1169 curr_event->args[idx] = va_arg(ap, long);
1170 va_end(ap);
1171 debug_finish_entry(id, active, level, 1);
1172 spin_unlock_irqrestore(&id->lock, flags);
1173
1174 return active;
1175}
1176EXPORT_SYMBOL(__debug_sprintf_exception);
1177
1178/**
1179 * debug_register_view() - registers new debug view and creates debugfs
1180 * dir entry
1181 *
1182 * @id: handle for debug log
1183 * @view: pointer to debug view struct
1184 *
1185 * Return:
1186 * - 0 : ok
1187 * - < 0: Error
1188 */
1189int debug_register_view(debug_info_t *id, struct debug_view *view)
1190{
1191 unsigned long flags;
1192 struct dentry *pde;
1193 umode_t mode;
1194 int rc = 0;
1195 int i;
1196
1197 if (!id)
1198 goto out;
1199 mode = (id->mode | S_IFREG) & ~S_IXUGO;
1200 if (!(view->prolog_proc || view->format_proc || view->header_proc))
1201 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1202 if (!view->input_proc)
1203 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1204 pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1205 id, &debug_file_ops);
1206 spin_lock_irqsave(&id->lock, flags);
1207 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1208 if (!id->views[i])
1209 break;
1210 }
1211 if (i == DEBUG_MAX_VIEWS) {
1212 rc = -1;
1213 } else {
1214 id->views[i] = view;
1215 id->debugfs_entries[i] = pde;
1216 }
1217 spin_unlock_irqrestore(&id->lock, flags);
1218 if (rc) {
1219 pr_err("Registering view %s/%s would exceed the maximum "
1220 "number of views %i\n", id->name, view->name, i);
1221 debugfs_remove(pde);
1222 }
1223out:
1224 return rc;
1225}
1226EXPORT_SYMBOL(debug_register_view);
1227
1228/**
1229 * debug_unregister_view() - unregisters debug view and removes debugfs
1230 * dir entry
1231 *
1232 * @id: handle for debug log
1233 * @view: pointer to debug view struct
1234 *
1235 * Return:
1236 * - 0 : ok
1237 * - < 0: Error
1238 */
1239int debug_unregister_view(debug_info_t *id, struct debug_view *view)
1240{
1241 struct dentry *dentry = NULL;
1242 unsigned long flags;
1243 int i, rc = 0;
1244
1245 if (!id)
1246 goto out;
1247 spin_lock_irqsave(&id->lock, flags);
1248 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1249 if (id->views[i] == view)
1250 break;
1251 }
1252 if (i == DEBUG_MAX_VIEWS) {
1253 rc = -1;
1254 } else {
1255 dentry = id->debugfs_entries[i];
1256 id->views[i] = NULL;
1257 id->debugfs_entries[i] = NULL;
1258 }
1259 spin_unlock_irqrestore(&id->lock, flags);
1260 debugfs_remove(dentry);
1261out:
1262 return rc;
1263}
1264EXPORT_SYMBOL(debug_unregister_view);
1265
1266static inline char *debug_get_user_string(const char __user *user_buf,
1267 size_t user_len)
1268{
1269 char *buffer;
1270
1271 buffer = kmalloc(user_len + 1, GFP_KERNEL);
1272 if (!buffer)
1273 return ERR_PTR(-ENOMEM);
1274 if (copy_from_user(buffer, user_buf, user_len) != 0) {
1275 kfree(buffer);
1276 return ERR_PTR(-EFAULT);
1277 }
1278 /* got the string, now strip linefeed. */
1279 if (buffer[user_len - 1] == '\n')
1280 buffer[user_len - 1] = 0;
1281 else
1282 buffer[user_len] = 0;
1283 return buffer;
1284}
1285
1286static inline int debug_get_uint(char *buf)
1287{
1288 int rc;
1289
1290 buf = skip_spaces(buf);
1291 rc = simple_strtoul(buf, &buf, 10);
1292 if (*buf)
1293 rc = -EINVAL;
1294 return rc;
1295}
1296
1297/*
1298 * functions for debug-views
1299 ***********************************
1300*/
1301
1302/*
1303 * prints out actual debug level
1304 */
1305
1306static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
1307 char *out_buf)
1308{
1309 return sprintf(out_buf, "%i\n", id->pages_per_area);
1310}
1311
1312/*
1313 * reads new size (number of pages per debug area)
1314 */
1315
1316static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
1317 struct file *file, const char __user *user_buf,
1318 size_t user_len, loff_t *offset)
1319{
1320 int rc, new_pages;
1321 char *str;
1322
1323 if (user_len > 0x10000)
1324 user_len = 0x10000;
1325 if (*offset != 0) {
1326 rc = -EPIPE;
1327 goto out;
1328 }
1329 str = debug_get_user_string(user_buf, user_len);
1330 if (IS_ERR(str)) {
1331 rc = PTR_ERR(str);
1332 goto out;
1333 }
1334 new_pages = debug_get_uint(str);
1335 if (new_pages < 0) {
1336 rc = -EINVAL;
1337 goto free_str;
1338 }
1339 rc = debug_set_size(id, id->nr_areas, new_pages);
1340 if (rc != 0) {
1341 rc = -EINVAL;
1342 goto free_str;
1343 }
1344 rc = user_len;
1345free_str:
1346 kfree(str);
1347out:
1348 *offset += user_len;
1349 return rc; /* number of input characters */
1350}
1351
1352/*
1353 * prints out actual debug level
1354 */
1355static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
1356 char *out_buf)
1357{
1358 int rc = 0;
1359
1360 if (id->level == DEBUG_OFF_LEVEL)
1361 rc = sprintf(out_buf, "-\n");
1362 else
1363 rc = sprintf(out_buf, "%i\n", id->level);
1364 return rc;
1365}
1366
1367/*
1368 * reads new debug level
1369 */
1370static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
1371 struct file *file, const char __user *user_buf,
1372 size_t user_len, loff_t *offset)
1373{
1374 int rc, new_level;
1375 char *str;
1376
1377 if (user_len > 0x10000)
1378 user_len = 0x10000;
1379 if (*offset != 0) {
1380 rc = -EPIPE;
1381 goto out;
1382 }
1383 str = debug_get_user_string(user_buf, user_len);
1384 if (IS_ERR(str)) {
1385 rc = PTR_ERR(str);
1386 goto out;
1387 }
1388 if (str[0] == '-') {
1389 debug_set_level(id, DEBUG_OFF_LEVEL);
1390 rc = user_len;
1391 goto free_str;
1392 } else {
1393 new_level = debug_get_uint(str);
1394 }
1395 if (new_level < 0) {
1396 pr_warn("%s is not a valid level for a debug feature\n", str);
1397 rc = -EINVAL;
1398 } else {
1399 debug_set_level(id, new_level);
1400 rc = user_len;
1401 }
1402free_str:
1403 kfree(str);
1404out:
1405 *offset += user_len;
1406 return rc; /* number of input characters */
1407}
1408
1409/*
1410 * flushes debug areas
1411 */
1412static void debug_flush(debug_info_t *id, int area)
1413{
1414 unsigned long flags;
1415 int i, j;
1416
1417 if (!id || !id->areas)
1418 return;
1419 spin_lock_irqsave(&id->lock, flags);
1420 if (area == DEBUG_FLUSH_ALL) {
1421 id->active_area = 0;
1422 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1423 for (i = 0; i < id->nr_areas; i++) {
1424 id->active_pages[i] = 0;
1425 for (j = 0; j < id->pages_per_area; j++)
1426 memset(id->areas[i][j], 0, PAGE_SIZE);
1427 }
1428 } else if (area >= 0 && area < id->nr_areas) {
1429 id->active_entries[area] = 0;
1430 id->active_pages[area] = 0;
1431 for (i = 0; i < id->pages_per_area; i++)
1432 memset(id->areas[area][i], 0, PAGE_SIZE);
1433 }
1434 spin_unlock_irqrestore(&id->lock, flags);
1435}
1436
1437/*
1438 * view function: flushes debug areas
1439 */
1440static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
1441 struct file *file, const char __user *user_buf,
1442 size_t user_len, loff_t *offset)
1443{
1444 char input_buf[1];
1445 int rc = user_len;
1446
1447 if (user_len > 0x10000)
1448 user_len = 0x10000;
1449 if (*offset != 0) {
1450 rc = -EPIPE;
1451 goto out;
1452 }
1453 if (copy_from_user(input_buf, user_buf, 1)) {
1454 rc = -EFAULT;
1455 goto out;
1456 }
1457 if (input_buf[0] == '-') {
1458 debug_flush(id, DEBUG_FLUSH_ALL);
1459 goto out;
1460 }
1461 if (isdigit(input_buf[0])) {
1462 int area = ((int) input_buf[0] - (int) '0');
1463
1464 debug_flush(id, area);
1465 goto out;
1466 }
1467
1468 pr_info("Flushing debug data failed because %c is not a valid "
1469 "area\n", input_buf[0]);
1470
1471out:
1472 *offset += user_len;
1473 return rc; /* number of input characters */
1474}
1475
1476/*
1477 * prints debug data in hex/ascii format
1478 */
1479static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
1480 char *out_buf, const char *in_buf)
1481{
1482 int i, rc = 0;
1483
1484 for (i = 0; i < id->buf_size; i++)
1485 rc += sprintf(out_buf + rc, "%02x ", ((unsigned char *) in_buf)[i]);
1486 rc += sprintf(out_buf + rc, "| ");
1487 for (i = 0; i < id->buf_size; i++) {
1488 unsigned char c = in_buf[i];
1489
1490 if (isascii(c) && isprint(c))
1491 rc += sprintf(out_buf + rc, "%c", c);
1492 else
1493 rc += sprintf(out_buf + rc, ".");
1494 }
1495 rc += sprintf(out_buf + rc, "\n");
1496 return rc;
1497}
1498
1499/*
1500 * prints header for debug entry
1501 */
1502int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
1503 int area, debug_entry_t *entry, char *out_buf)
1504{
1505 unsigned long sec, usec;
1506 unsigned long caller;
1507 unsigned int level;
1508 char *except_str;
1509 int rc = 0;
1510
1511 level = entry->level;
1512 sec = entry->clock;
1513 usec = do_div(sec, USEC_PER_SEC);
1514
1515 if (entry->exception)
1516 except_str = "*";
1517 else
1518 except_str = "-";
1519 caller = (unsigned long) entry->caller;
1520 rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %04u %px ",
1521 area, sec, usec, level, except_str,
1522 entry->cpu, (void *)caller);
1523 return rc;
1524}
1525EXPORT_SYMBOL(debug_dflt_header_fn);
1526
1527/*
1528 * prints debug data sprintf-formated:
1529 * debug_sprinf_event/exception calls must be used together with this view
1530 */
1531
1532#define DEBUG_SPRINTF_MAX_ARGS 10
1533
1534static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
1535 char *out_buf, const char *inbuf)
1536{
1537 debug_sprintf_entry_t *curr_event = (debug_sprintf_entry_t *)inbuf;
1538 int num_longs, num_used_args = 0, i, rc = 0;
1539 int index[DEBUG_SPRINTF_MAX_ARGS];
1540
1541 /* count of longs fit into one entry */
1542 num_longs = id->buf_size / sizeof(long);
1543
1544 if (num_longs < 1)
1545 goto out; /* bufsize of entry too small */
1546 if (num_longs == 1) {
1547 /* no args, we use only the string */
1548 strcpy(out_buf, curr_event->string);
1549 rc = strlen(curr_event->string);
1550 goto out;
1551 }
1552
1553 /* number of arguments used for sprintf (without the format string) */
1554 num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1555
1556 memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1557
1558 for (i = 0; i < num_used_args; i++)
1559 index[i] = i;
1560
1561 rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1562 curr_event->args[index[1]], curr_event->args[index[2]],
1563 curr_event->args[index[3]], curr_event->args[index[4]],
1564 curr_event->args[index[5]], curr_event->args[index[6]],
1565 curr_event->args[index[7]], curr_event->args[index[8]],
1566 curr_event->args[index[9]]);
1567out:
1568 return rc;
1569}
1570
1571/*
1572 * debug_init:
1573 * - is called exactly once to initialize the debug feature
1574 */
1575static int __init debug_init(void)
1576{
1577 s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
1578 mutex_lock(&debug_mutex);
1579 debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1580 initialized = 1;
1581 mutex_unlock(&debug_mutex);
1582 return 0;
1583}
1584postcore_initcall(debug_init);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * S/390 debug facility
4 *
5 * Copyright IBM Corp. 1999, 2012
6 *
7 * Author(s): Michael Holzheu (holzheu@de.ibm.com),
8 * Holger Smolinski (Holger.Smolinski@de.ibm.com)
9 *
10 * Bugreports to: <Linux390@de.ibm.com>
11 */
12
13#define KMSG_COMPONENT "s390dbf"
14#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
15
16#include <linux/stddef.h>
17#include <linux/kernel.h>
18#include <linux/errno.h>
19#include <linux/slab.h>
20#include <linux/ctype.h>
21#include <linux/string.h>
22#include <linux/sysctl.h>
23#include <linux/uaccess.h>
24#include <linux/export.h>
25#include <linux/init.h>
26#include <linux/fs.h>
27#include <linux/debugfs.h>
28
29#include <asm/debug.h>
30
31#define DEBUG_PROLOG_ENTRY -1
32
33#define ALL_AREAS 0 /* copy all debug areas */
34#define NO_AREAS 1 /* copy no debug areas */
35
36/* typedefs */
37
38typedef struct file_private_info {
39 loff_t offset; /* offset of last read in file */
40 int act_area; /* number of last formated area */
41 int act_page; /* act page in given area */
42 int act_entry; /* last formated entry (offset */
43 /* relative to beginning of last */
44 /* formated page) */
45 size_t act_entry_offset; /* up to this offset we copied */
46 /* in last read the last formated */
47 /* entry to userland */
48 char temp_buf[2048]; /* buffer for output */
49 debug_info_t *debug_info_org; /* original debug information */
50 debug_info_t *debug_info_snap; /* snapshot of debug information */
51 struct debug_view *view; /* used view of debug info */
52} file_private_info_t;
53
54typedef struct {
55 char *string;
56 /*
57 * This assumes that all args are converted into longs
58 * on L/390 this is the case for all types of parameter
59 * except of floats, and long long (32 bit)
60 *
61 */
62 long args[0];
63} debug_sprintf_entry_t;
64
65/* internal function prototyes */
66
67static int debug_init(void);
68static ssize_t debug_output(struct file *file, char __user *user_buf,
69 size_t user_len, loff_t *offset);
70static ssize_t debug_input(struct file *file, const char __user *user_buf,
71 size_t user_len, loff_t *offset);
72static int debug_open(struct inode *inode, struct file *file);
73static int debug_close(struct inode *inode, struct file *file);
74static debug_info_t *debug_info_create(const char *name, int pages_per_area,
75 int nr_areas, int buf_size, umode_t mode);
76static void debug_info_get(debug_info_t *);
77static void debug_info_put(debug_info_t *);
78static int debug_prolog_level_fn(debug_info_t *id,
79 struct debug_view *view, char *out_buf);
80static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
81 struct file *file, const char __user *user_buf,
82 size_t user_buf_size, loff_t *offset);
83static int debug_prolog_pages_fn(debug_info_t *id,
84 struct debug_view *view, char *out_buf);
85static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
86 struct file *file, const char __user *user_buf,
87 size_t user_buf_size, loff_t *offset);
88static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
89 struct file *file, const char __user *user_buf,
90 size_t user_buf_size, loff_t *offset);
91static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
92 char *out_buf, const char *in_buf);
93static int debug_raw_format_fn(debug_info_t *id,
94 struct debug_view *view, char *out_buf,
95 const char *in_buf);
96static int debug_raw_header_fn(debug_info_t *id, struct debug_view *view,
97 int area, debug_entry_t *entry, char *out_buf);
98
99static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
100 char *out_buf, debug_sprintf_entry_t *curr_event);
101
102/* globals */
103
104struct debug_view debug_raw_view = {
105 "raw",
106 NULL,
107 &debug_raw_header_fn,
108 &debug_raw_format_fn,
109 NULL,
110 NULL
111};
112EXPORT_SYMBOL(debug_raw_view);
113
114struct debug_view debug_hex_ascii_view = {
115 "hex_ascii",
116 NULL,
117 &debug_dflt_header_fn,
118 &debug_hex_ascii_format_fn,
119 NULL,
120 NULL
121};
122EXPORT_SYMBOL(debug_hex_ascii_view);
123
124static struct debug_view debug_level_view = {
125 "level",
126 &debug_prolog_level_fn,
127 NULL,
128 NULL,
129 &debug_input_level_fn,
130 NULL
131};
132
133static struct debug_view debug_pages_view = {
134 "pages",
135 &debug_prolog_pages_fn,
136 NULL,
137 NULL,
138 &debug_input_pages_fn,
139 NULL
140};
141
142static struct debug_view debug_flush_view = {
143 "flush",
144 NULL,
145 NULL,
146 NULL,
147 &debug_input_flush_fn,
148 NULL
149};
150
151struct debug_view debug_sprintf_view = {
152 "sprintf",
153 NULL,
154 &debug_dflt_header_fn,
155 (debug_format_proc_t *)&debug_sprintf_format_fn,
156 NULL,
157 NULL
158};
159EXPORT_SYMBOL(debug_sprintf_view);
160
161/* used by dump analysis tools to determine version of debug feature */
162static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
163
164/* static globals */
165
166static debug_info_t *debug_area_first;
167static debug_info_t *debug_area_last;
168static DEFINE_MUTEX(debug_mutex);
169
170static int initialized;
171static int debug_critical;
172
173static const struct file_operations debug_file_ops = {
174 .owner = THIS_MODULE,
175 .read = debug_output,
176 .write = debug_input,
177 .open = debug_open,
178 .release = debug_close,
179 .llseek = no_llseek,
180};
181
182static struct dentry *debug_debugfs_root_entry;
183
184/* functions */
185
186/*
187 * debug_areas_alloc
188 * - Debug areas are implemented as a threedimensonal array:
189 * areas[areanumber][pagenumber][pageoffset]
190 */
191
192static debug_entry_t ***debug_areas_alloc(int pages_per_area, int nr_areas)
193{
194 debug_entry_t ***areas;
195 int i, j;
196
197 areas = kmalloc(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(pages_per_area * sizeof(debug_entry_t *), GFP_KERNEL);
202 if (!areas[i])
203 goto fail_malloc_areas2;
204 for (j = 0; j < pages_per_area; j++) {
205 areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
206 if (!areas[i][j]) {
207 for (j--; j >= 0 ; j--)
208 kfree(areas[i][j]);
209 kfree(areas[i]);
210 goto fail_malloc_areas2;
211 }
212 }
213 }
214 return areas;
215
216fail_malloc_areas2:
217 for (i--; i >= 0; i--) {
218 for (j = 0; j < pages_per_area; j++)
219 kfree(areas[i][j]);
220 kfree(areas[i]);
221 }
222 kfree(areas);
223fail_malloc_areas:
224 return NULL;
225}
226
227/*
228 * debug_info_alloc
229 * - alloc new debug-info
230 */
231static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,
232 int nr_areas, int buf_size, int level,
233 int mode)
234{
235 debug_info_t *rc;
236
237 /* alloc everything */
238 rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
239 if (!rc)
240 goto fail_malloc_rc;
241 rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
242 if (!rc->active_entries)
243 goto fail_malloc_active_entries;
244 rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
245 if (!rc->active_pages)
246 goto fail_malloc_active_pages;
247 if ((mode == ALL_AREAS) && (pages_per_area != 0)) {
248 rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
249 if (!rc->areas)
250 goto fail_malloc_areas;
251 } else {
252 rc->areas = NULL;
253 }
254
255 /* initialize members */
256 spin_lock_init(&rc->lock);
257 rc->pages_per_area = pages_per_area;
258 rc->nr_areas = nr_areas;
259 rc->active_area = 0;
260 rc->level = level;
261 rc->buf_size = buf_size;
262 rc->entry_size = sizeof(debug_entry_t) + buf_size;
263 strlcpy(rc->name, name, sizeof(rc->name));
264 memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
265 memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
266 refcount_set(&(rc->ref_count), 0);
267
268 return rc;
269
270fail_malloc_areas:
271 kfree(rc->active_pages);
272fail_malloc_active_pages:
273 kfree(rc->active_entries);
274fail_malloc_active_entries:
275 kfree(rc);
276fail_malloc_rc:
277 return NULL;
278}
279
280/*
281 * debug_areas_free
282 * - free all debug areas
283 */
284static void debug_areas_free(debug_info_t *db_info)
285{
286 int i, j;
287
288 if (!db_info->areas)
289 return;
290 for (i = 0; i < db_info->nr_areas; i++) {
291 for (j = 0; j < db_info->pages_per_area; j++)
292 kfree(db_info->areas[i][j]);
293 kfree(db_info->areas[i]);
294 }
295 kfree(db_info->areas);
296 db_info->areas = NULL;
297}
298
299/*
300 * debug_info_free
301 * - free memory debug-info
302 */
303static void debug_info_free(debug_info_t *db_info)
304{
305 debug_areas_free(db_info);
306 kfree(db_info->active_entries);
307 kfree(db_info->active_pages);
308 kfree(db_info);
309}
310
311/*
312 * debug_info_create
313 * - create new debug-info
314 */
315
316static debug_info_t *debug_info_create(const char *name, int pages_per_area,
317 int nr_areas, int buf_size, umode_t mode)
318{
319 debug_info_t *rc;
320
321 rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
322 DEBUG_DEFAULT_LEVEL, ALL_AREAS);
323 if (!rc)
324 goto out;
325
326 rc->mode = mode & ~S_IFMT;
327
328 /* create root directory */
329 rc->debugfs_root_entry = debugfs_create_dir(rc->name,
330 debug_debugfs_root_entry);
331
332 /* append new element to linked list */
333 if (!debug_area_first) {
334 /* first element in list */
335 debug_area_first = rc;
336 rc->prev = NULL;
337 } else {
338 /* append element to end of list */
339 debug_area_last->next = rc;
340 rc->prev = debug_area_last;
341 }
342 debug_area_last = rc;
343 rc->next = NULL;
344
345 refcount_set(&rc->ref_count, 1);
346out:
347 return rc;
348}
349
350/*
351 * debug_info_copy
352 * - copy debug-info
353 */
354static debug_info_t *debug_info_copy(debug_info_t *in, int mode)
355{
356 unsigned long flags;
357 debug_info_t *rc;
358 int i, j;
359
360 /* get a consistent copy of the debug areas */
361 do {
362 rc = debug_info_alloc(in->name, in->pages_per_area,
363 in->nr_areas, in->buf_size, in->level, mode);
364 spin_lock_irqsave(&in->lock, flags);
365 if (!rc)
366 goto out;
367 /* has something changed in the meantime ? */
368 if ((rc->pages_per_area == in->pages_per_area) &&
369 (rc->nr_areas == in->nr_areas)) {
370 break;
371 }
372 spin_unlock_irqrestore(&in->lock, flags);
373 debug_info_free(rc);
374 } while (1);
375
376 if (mode == NO_AREAS)
377 goto out;
378
379 for (i = 0; i < in->nr_areas; i++) {
380 for (j = 0; j < in->pages_per_area; j++)
381 memcpy(rc->areas[i][j], in->areas[i][j], PAGE_SIZE);
382 }
383out:
384 spin_unlock_irqrestore(&in->lock, flags);
385 return rc;
386}
387
388/*
389 * debug_info_get
390 * - increments reference count for debug-info
391 */
392static void debug_info_get(debug_info_t *db_info)
393{
394 if (db_info)
395 refcount_inc(&db_info->ref_count);
396}
397
398/*
399 * debug_info_put:
400 * - decreases reference count for debug-info and frees it if necessary
401 */
402static void debug_info_put(debug_info_t *db_info)
403{
404 int i;
405
406 if (!db_info)
407 return;
408 if (refcount_dec_and_test(&db_info->ref_count)) {
409 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
410 if (!db_info->views[i])
411 continue;
412 debugfs_remove(db_info->debugfs_entries[i]);
413 }
414 debugfs_remove(db_info->debugfs_root_entry);
415 if (db_info == debug_area_first)
416 debug_area_first = db_info->next;
417 if (db_info == debug_area_last)
418 debug_area_last = db_info->prev;
419 if (db_info->prev)
420 db_info->prev->next = db_info->next;
421 if (db_info->next)
422 db_info->next->prev = db_info->prev;
423 debug_info_free(db_info);
424 }
425}
426
427/*
428 * debug_format_entry:
429 * - format one debug entry and return size of formated data
430 */
431static int debug_format_entry(file_private_info_t *p_info)
432{
433 debug_info_t *id_snap = p_info->debug_info_snap;
434 struct debug_view *view = p_info->view;
435 debug_entry_t *act_entry;
436 size_t len = 0;
437
438 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
439 /* print prolog */
440 if (view->prolog_proc)
441 len += view->prolog_proc(id_snap, view, p_info->temp_buf);
442 goto out;
443 }
444 if (!id_snap->areas) /* this is true, if we have a prolog only view */
445 goto out; /* or if 'pages_per_area' is 0 */
446 act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
447 [p_info->act_page] + p_info->act_entry);
448
449 if (act_entry->id.stck == 0LL)
450 goto out; /* empty entry */
451 if (view->header_proc)
452 len += view->header_proc(id_snap, view, p_info->act_area,
453 act_entry, p_info->temp_buf + len);
454 if (view->format_proc)
455 len += view->format_proc(id_snap, view, p_info->temp_buf + len,
456 DEBUG_DATA(act_entry));
457out:
458 return len;
459}
460
461/*
462 * debug_next_entry:
463 * - goto next entry in p_info
464 */
465static inline int debug_next_entry(file_private_info_t *p_info)
466{
467 debug_info_t *id;
468
469 id = p_info->debug_info_snap;
470 if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {
471 p_info->act_entry = 0;
472 p_info->act_page = 0;
473 goto out;
474 }
475 if (!id->areas)
476 return 1;
477 p_info->act_entry += id->entry_size;
478 /* switch to next page, if we reached the end of the page */
479 if (p_info->act_entry > (PAGE_SIZE - id->entry_size)) {
480 /* next page */
481 p_info->act_entry = 0;
482 p_info->act_page += 1;
483 if ((p_info->act_page % id->pages_per_area) == 0) {
484 /* next area */
485 p_info->act_area++;
486 p_info->act_page = 0;
487 }
488 if (p_info->act_area >= id->nr_areas)
489 return 1;
490 }
491out:
492 return 0;
493}
494
495/*
496 * debug_output:
497 * - called for user read()
498 * - copies formated debug entries to the user buffer
499 */
500static ssize_t debug_output(struct file *file, /* file descriptor */
501 char __user *user_buf, /* user buffer */
502 size_t len, /* length of buffer */
503 loff_t *offset) /* offset in the file */
504{
505 size_t count = 0;
506 size_t entry_offset;
507 file_private_info_t *p_info;
508
509 p_info = (file_private_info_t *) file->private_data;
510 if (*offset != p_info->offset)
511 return -EPIPE;
512 if (p_info->act_area >= p_info->debug_info_snap->nr_areas)
513 return 0;
514 entry_offset = p_info->act_entry_offset;
515 while (count < len) {
516 int formatted_line_residue;
517 int formatted_line_size;
518 int user_buf_residue;
519 size_t copy_size;
520
521 formatted_line_size = debug_format_entry(p_info);
522 formatted_line_residue = formatted_line_size - entry_offset;
523 user_buf_residue = len-count;
524 copy_size = min(user_buf_residue, formatted_line_residue);
525 if (copy_size) {
526 if (copy_to_user(user_buf + count, p_info->temp_buf
527 + entry_offset, copy_size))
528 return -EFAULT;
529 count += copy_size;
530 entry_offset += copy_size;
531 }
532 if (copy_size == formatted_line_residue) {
533 entry_offset = 0;
534 if (debug_next_entry(p_info))
535 goto out;
536 }
537 }
538out:
539 p_info->offset = *offset + count;
540 p_info->act_entry_offset = entry_offset;
541 *offset = p_info->offset;
542 return count;
543}
544
545/*
546 * debug_input:
547 * - called for user write()
548 * - calls input function of view
549 */
550static ssize_t debug_input(struct file *file, const char __user *user_buf,
551 size_t length, loff_t *offset)
552{
553 file_private_info_t *p_info;
554 int rc = 0;
555
556 mutex_lock(&debug_mutex);
557 p_info = ((file_private_info_t *) file->private_data);
558 if (p_info->view->input_proc) {
559 rc = p_info->view->input_proc(p_info->debug_info_org,
560 p_info->view, file, user_buf,
561 length, offset);
562 } else {
563 rc = -EPERM;
564 }
565 mutex_unlock(&debug_mutex);
566 return rc; /* number of input characters */
567}
568
569/*
570 * debug_open:
571 * - called for user open()
572 * - copies formated output to private_data area of the file
573 * handle
574 */
575static int debug_open(struct inode *inode, struct file *file)
576{
577 debug_info_t *debug_info, *debug_info_snapshot;
578 file_private_info_t *p_info;
579 int i, rc = 0;
580
581 mutex_lock(&debug_mutex);
582 debug_info = file_inode(file)->i_private;
583 /* find debug view */
584 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
585 if (!debug_info->views[i])
586 continue;
587 else if (debug_info->debugfs_entries[i] == file->f_path.dentry)
588 goto found; /* found view ! */
589 }
590 /* no entry found */
591 rc = -EINVAL;
592 goto out;
593
594found:
595
596 /* Make snapshot of current debug areas to get it consistent. */
597 /* To copy all the areas is only needed, if we have a view which */
598 /* formats the debug areas. */
599
600 if (!debug_info->views[i]->format_proc && !debug_info->views[i]->header_proc)
601 debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
602 else
603 debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
604
605 if (!debug_info_snapshot) {
606 rc = -ENOMEM;
607 goto out;
608 }
609 p_info = kmalloc(sizeof(file_private_info_t), GFP_KERNEL);
610 if (!p_info) {
611 debug_info_free(debug_info_snapshot);
612 rc = -ENOMEM;
613 goto out;
614 }
615 p_info->offset = 0;
616 p_info->debug_info_snap = debug_info_snapshot;
617 p_info->debug_info_org = debug_info;
618 p_info->view = debug_info->views[i];
619 p_info->act_area = 0;
620 p_info->act_page = 0;
621 p_info->act_entry = DEBUG_PROLOG_ENTRY;
622 p_info->act_entry_offset = 0;
623 file->private_data = p_info;
624 debug_info_get(debug_info);
625 nonseekable_open(inode, file);
626out:
627 mutex_unlock(&debug_mutex);
628 return rc;
629}
630
631/*
632 * debug_close:
633 * - called for user close()
634 * - deletes private_data area of the file handle
635 */
636static int debug_close(struct inode *inode, struct file *file)
637{
638 file_private_info_t *p_info;
639
640 p_info = (file_private_info_t *) file->private_data;
641 if (p_info->debug_info_snap)
642 debug_info_free(p_info->debug_info_snap);
643 debug_info_put(p_info->debug_info_org);
644 kfree(file->private_data);
645 return 0; /* success */
646}
647
648/*
649 * debug_register_mode:
650 * - Creates and initializes debug area for the caller
651 * The mode parameter allows to specify access rights for the s390dbf files
652 * - Returns handle for debug area
653 */
654debug_info_t *debug_register_mode(const char *name, int pages_per_area,
655 int nr_areas, int buf_size, umode_t mode,
656 uid_t uid, gid_t gid)
657{
658 debug_info_t *rc = NULL;
659
660 /* Since debugfs currently does not support uid/gid other than root, */
661 /* we do not allow gid/uid != 0 until we get support for that. */
662 if ((uid != 0) || (gid != 0))
663 pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
664 BUG_ON(!initialized);
665 mutex_lock(&debug_mutex);
666
667 /* create new debug_info */
668 rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
669 if (!rc)
670 goto out;
671 debug_register_view(rc, &debug_level_view);
672 debug_register_view(rc, &debug_flush_view);
673 debug_register_view(rc, &debug_pages_view);
674out:
675 if (!rc)
676 pr_err("Registering debug feature %s failed\n", name);
677 mutex_unlock(&debug_mutex);
678 return rc;
679}
680EXPORT_SYMBOL(debug_register_mode);
681
682/*
683 * debug_register:
684 * - creates and initializes debug area for the caller
685 * - returns handle for debug area
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/*
696 * debug_unregister:
697 * - give back debug area
698 */
699void debug_unregister(debug_info_t *id)
700{
701 if (!id)
702 return;
703 mutex_lock(&debug_mutex);
704 debug_info_put(id);
705 mutex_unlock(&debug_mutex);
706}
707EXPORT_SYMBOL(debug_unregister);
708
709/*
710 * debug_set_size:
711 * - set area size (number of pages) and number of areas
712 */
713static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
714{
715 debug_entry_t ***new_areas;
716 unsigned long flags;
717 int rc = 0;
718
719 if (!id || (nr_areas <= 0) || (pages_per_area < 0))
720 return -EINVAL;
721 if (pages_per_area > 0) {
722 new_areas = debug_areas_alloc(pages_per_area, nr_areas);
723 if (!new_areas) {
724 pr_info("Allocating memory for %i pages failed\n",
725 pages_per_area);
726 rc = -ENOMEM;
727 goto out;
728 }
729 } else {
730 new_areas = NULL;
731 }
732 spin_lock_irqsave(&id->lock, flags);
733 debug_areas_free(id);
734 id->areas = new_areas;
735 id->nr_areas = nr_areas;
736 id->pages_per_area = pages_per_area;
737 id->active_area = 0;
738 memset(id->active_entries, 0, sizeof(int)*id->nr_areas);
739 memset(id->active_pages, 0, sizeof(int)*id->nr_areas);
740 spin_unlock_irqrestore(&id->lock, flags);
741 pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
742out:
743 return rc;
744}
745
746/*
747 * debug_set_level:
748 * - set actual debug level
749 */
750void debug_set_level(debug_info_t *id, int new_level)
751{
752 unsigned long flags;
753
754 if (!id)
755 return;
756 spin_lock_irqsave(&id->lock, flags);
757 if (new_level == DEBUG_OFF_LEVEL) {
758 id->level = DEBUG_OFF_LEVEL;
759 pr_info("%s: switched off\n", id->name);
760 } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
761 pr_info("%s: level %i is out of range (%i - %i)\n",
762 id->name, new_level, 0, DEBUG_MAX_LEVEL);
763 } else {
764 id->level = new_level;
765 }
766 spin_unlock_irqrestore(&id->lock, flags);
767}
768EXPORT_SYMBOL(debug_set_level);
769
770/*
771 * proceed_active_entry:
772 * - set active entry to next in the ring buffer
773 */
774static inline void proceed_active_entry(debug_info_t *id)
775{
776 if ((id->active_entries[id->active_area] += id->entry_size)
777 > (PAGE_SIZE - id->entry_size)) {
778 id->active_entries[id->active_area] = 0;
779 id->active_pages[id->active_area] =
780 (id->active_pages[id->active_area] + 1) %
781 id->pages_per_area;
782 }
783}
784
785/*
786 * proceed_active_area:
787 * - set active area to next in the ring buffer
788 */
789static inline void proceed_active_area(debug_info_t *id)
790{
791 id->active_area++;
792 id->active_area = id->active_area % id->nr_areas;
793}
794
795/*
796 * get_active_entry:
797 */
798static inline debug_entry_t *get_active_entry(debug_info_t *id)
799{
800 return (debug_entry_t *) (((char *) id->areas[id->active_area]
801 [id->active_pages[id->active_area]]) +
802 id->active_entries[id->active_area]);
803}
804
805/*
806 * debug_finish_entry:
807 * - set timestamp, caller address, cpu number etc.
808 */
809
810static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
811 int level, int exception)
812{
813 active->id.stck = get_tod_clock_fast() -
814 *(unsigned long long *) &tod_clock_base[1];
815 active->id.fields.cpuid = smp_processor_id();
816 active->caller = __builtin_return_address(0);
817 active->id.fields.exception = exception;
818 active->id.fields.level = level;
819 proceed_active_entry(id);
820 if (exception)
821 proceed_active_area(id);
822}
823
824static int debug_stoppable = 1;
825static int debug_active = 1;
826
827#define CTL_S390DBF_STOPPABLE 5678
828#define CTL_S390DBF_ACTIVE 5679
829
830/*
831 * proc handler for the running debug_active sysctl
832 * always allow read, allow write only if debug_stoppable is set or
833 * if debug_active is already off
834 */
835static int s390dbf_procactive(struct ctl_table *table, int write,
836 void __user *buffer, size_t *lenp, loff_t *ppos)
837{
838 if (!write || debug_stoppable || !debug_active)
839 return proc_dointvec(table, write, buffer, lenp, ppos);
840 else
841 return 0;
842}
843
844static struct ctl_table s390dbf_table[] = {
845 {
846 .procname = "debug_stoppable",
847 .data = &debug_stoppable,
848 .maxlen = sizeof(int),
849 .mode = S_IRUGO | S_IWUSR,
850 .proc_handler = proc_dointvec,
851 },
852 {
853 .procname = "debug_active",
854 .data = &debug_active,
855 .maxlen = sizeof(int),
856 .mode = S_IRUGO | S_IWUSR,
857 .proc_handler = s390dbf_procactive,
858 },
859 { }
860};
861
862static struct ctl_table s390dbf_dir_table[] = {
863 {
864 .procname = "s390dbf",
865 .maxlen = 0,
866 .mode = S_IRUGO | S_IXUGO,
867 .child = s390dbf_table,
868 },
869 { }
870};
871
872static struct ctl_table_header *s390dbf_sysctl_header;
873
874void debug_stop_all(void)
875{
876 if (debug_stoppable)
877 debug_active = 0;
878}
879EXPORT_SYMBOL(debug_stop_all);
880
881void debug_set_critical(void)
882{
883 debug_critical = 1;
884}
885
886/*
887 * debug_event_common:
888 * - write debug entry with given size
889 */
890debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
891 int len)
892{
893 debug_entry_t *active;
894 unsigned long flags;
895
896 if (!debug_active || !id->areas)
897 return NULL;
898 if (debug_critical) {
899 if (!spin_trylock_irqsave(&id->lock, flags))
900 return NULL;
901 } else {
902 spin_lock_irqsave(&id->lock, flags);
903 }
904 do {
905 active = get_active_entry(id);
906 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
907 if (len < id->buf_size)
908 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
909 debug_finish_entry(id, active, level, 0);
910 len -= id->buf_size;
911 buf += id->buf_size;
912 } while (len > 0);
913
914 spin_unlock_irqrestore(&id->lock, flags);
915 return active;
916}
917EXPORT_SYMBOL(debug_event_common);
918
919/*
920 * debug_exception_common:
921 * - write debug entry with given size and switch to next debug area
922 */
923debug_entry_t *debug_exception_common(debug_info_t *id, int level,
924 const void *buf, int len)
925{
926 debug_entry_t *active;
927 unsigned long flags;
928
929 if (!debug_active || !id->areas)
930 return NULL;
931 if (debug_critical) {
932 if (!spin_trylock_irqsave(&id->lock, flags))
933 return NULL;
934 } else {
935 spin_lock_irqsave(&id->lock, flags);
936 }
937 do {
938 active = get_active_entry(id);
939 memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
940 if (len < id->buf_size)
941 memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
942 debug_finish_entry(id, active, level, len <= id->buf_size);
943 len -= id->buf_size;
944 buf += id->buf_size;
945 } while (len > 0);
946
947 spin_unlock_irqrestore(&id->lock, flags);
948 return active;
949}
950EXPORT_SYMBOL(debug_exception_common);
951
952/*
953 * counts arguments in format string for sprintf view
954 */
955static inline int debug_count_numargs(char *string)
956{
957 int numargs = 0;
958
959 while (*string) {
960 if (*string++ == '%')
961 numargs++;
962 }
963 return numargs;
964}
965
966/*
967 * debug_sprintf_event:
968 */
969debug_entry_t *__debug_sprintf_event(debug_info_t *id, int level, char *string, ...)
970{
971 debug_sprintf_entry_t *curr_event;
972 debug_entry_t *active;
973 unsigned long flags;
974 int numargs, idx;
975 va_list ap;
976
977 if (!debug_active || !id->areas)
978 return NULL;
979 numargs = debug_count_numargs(string);
980
981 if (debug_critical) {
982 if (!spin_trylock_irqsave(&id->lock, flags))
983 return NULL;
984 } else {
985 spin_lock_irqsave(&id->lock, flags);
986 }
987 active = get_active_entry(id);
988 curr_event = (debug_sprintf_entry_t *) DEBUG_DATA(active);
989 va_start(ap, string);
990 curr_event->string = string;
991 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
992 curr_event->args[idx] = va_arg(ap, long);
993 va_end(ap);
994 debug_finish_entry(id, active, level, 0);
995 spin_unlock_irqrestore(&id->lock, flags);
996
997 return active;
998}
999EXPORT_SYMBOL(__debug_sprintf_event);
1000
1001/*
1002 * debug_sprintf_exception:
1003 */
1004debug_entry_t *__debug_sprintf_exception(debug_info_t *id, int level, char *string, ...)
1005{
1006 debug_sprintf_entry_t *curr_event;
1007 debug_entry_t *active;
1008 unsigned long flags;
1009 int numargs, idx;
1010 va_list ap;
1011
1012 if (!debug_active || !id->areas)
1013 return NULL;
1014
1015 numargs = debug_count_numargs(string);
1016
1017 if (debug_critical) {
1018 if (!spin_trylock_irqsave(&id->lock, flags))
1019 return NULL;
1020 } else {
1021 spin_lock_irqsave(&id->lock, flags);
1022 }
1023 active = get_active_entry(id);
1024 curr_event = (debug_sprintf_entry_t *)DEBUG_DATA(active);
1025 va_start(ap, string);
1026 curr_event->string = string;
1027 for (idx = 0; idx < min(numargs, (int)(id->buf_size / sizeof(long)) - 1); idx++)
1028 curr_event->args[idx] = va_arg(ap, long);
1029 va_end(ap);
1030 debug_finish_entry(id, active, level, 1);
1031 spin_unlock_irqrestore(&id->lock, flags);
1032
1033 return active;
1034}
1035EXPORT_SYMBOL(__debug_sprintf_exception);
1036
1037/*
1038 * debug_register_view:
1039 */
1040int debug_register_view(debug_info_t *id, struct debug_view *view)
1041{
1042 unsigned long flags;
1043 struct dentry *pde;
1044 umode_t mode;
1045 int rc = 0;
1046 int i;
1047
1048 if (!id)
1049 goto out;
1050 mode = (id->mode | S_IFREG) & ~S_IXUGO;
1051 if (!(view->prolog_proc || view->format_proc || view->header_proc))
1052 mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1053 if (!view->input_proc)
1054 mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1055 pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1056 id, &debug_file_ops);
1057 if (!pde) {
1058 pr_err("Registering view %s/%s failed due to out of "
1059 "memory\n", id->name, view->name);
1060 rc = -1;
1061 goto out;
1062 }
1063 spin_lock_irqsave(&id->lock, flags);
1064 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1065 if (!id->views[i])
1066 break;
1067 }
1068 if (i == DEBUG_MAX_VIEWS) {
1069 pr_err("Registering view %s/%s would exceed the maximum "
1070 "number of views %i\n", id->name, view->name, i);
1071 rc = -1;
1072 } else {
1073 id->views[i] = view;
1074 id->debugfs_entries[i] = pde;
1075 }
1076 spin_unlock_irqrestore(&id->lock, flags);
1077 if (rc)
1078 debugfs_remove(pde);
1079out:
1080 return rc;
1081}
1082EXPORT_SYMBOL(debug_register_view);
1083
1084/*
1085 * debug_unregister_view:
1086 */
1087int debug_unregister_view(debug_info_t *id, struct debug_view *view)
1088{
1089 struct dentry *dentry = NULL;
1090 unsigned long flags;
1091 int i, rc = 0;
1092
1093 if (!id)
1094 goto out;
1095 spin_lock_irqsave(&id->lock, flags);
1096 for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1097 if (id->views[i] == view)
1098 break;
1099 }
1100 if (i == DEBUG_MAX_VIEWS) {
1101 rc = -1;
1102 } else {
1103 dentry = id->debugfs_entries[i];
1104 id->views[i] = NULL;
1105 id->debugfs_entries[i] = NULL;
1106 }
1107 spin_unlock_irqrestore(&id->lock, flags);
1108 debugfs_remove(dentry);
1109out:
1110 return rc;
1111}
1112EXPORT_SYMBOL(debug_unregister_view);
1113
1114static inline char *debug_get_user_string(const char __user *user_buf,
1115 size_t user_len)
1116{
1117 char *buffer;
1118
1119 buffer = kmalloc(user_len + 1, GFP_KERNEL);
1120 if (!buffer)
1121 return ERR_PTR(-ENOMEM);
1122 if (copy_from_user(buffer, user_buf, user_len) != 0) {
1123 kfree(buffer);
1124 return ERR_PTR(-EFAULT);
1125 }
1126 /* got the string, now strip linefeed. */
1127 if (buffer[user_len - 1] == '\n')
1128 buffer[user_len - 1] = 0;
1129 else
1130 buffer[user_len] = 0;
1131 return buffer;
1132}
1133
1134static inline int debug_get_uint(char *buf)
1135{
1136 int rc;
1137
1138 buf = skip_spaces(buf);
1139 rc = simple_strtoul(buf, &buf, 10);
1140 if (*buf)
1141 rc = -EINVAL;
1142 return rc;
1143}
1144
1145/*
1146 * functions for debug-views
1147 ***********************************
1148*/
1149
1150/*
1151 * prints out actual debug level
1152 */
1153
1154static int debug_prolog_pages_fn(debug_info_t *id, struct debug_view *view,
1155 char *out_buf)
1156{
1157 return sprintf(out_buf, "%i\n", id->pages_per_area);
1158}
1159
1160/*
1161 * reads new size (number of pages per debug area)
1162 */
1163
1164static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,
1165 struct file *file, const char __user *user_buf,
1166 size_t user_len, loff_t *offset)
1167{
1168 int rc, new_pages;
1169 char *str;
1170
1171 if (user_len > 0x10000)
1172 user_len = 0x10000;
1173 if (*offset != 0) {
1174 rc = -EPIPE;
1175 goto out;
1176 }
1177 str = debug_get_user_string(user_buf, user_len);
1178 if (IS_ERR(str)) {
1179 rc = PTR_ERR(str);
1180 goto out;
1181 }
1182 new_pages = debug_get_uint(str);
1183 if (new_pages < 0) {
1184 rc = -EINVAL;
1185 goto free_str;
1186 }
1187 rc = debug_set_size(id, id->nr_areas, new_pages);
1188 if (rc != 0) {
1189 rc = -EINVAL;
1190 goto free_str;
1191 }
1192 rc = user_len;
1193free_str:
1194 kfree(str);
1195out:
1196 *offset += user_len;
1197 return rc; /* number of input characters */
1198}
1199
1200/*
1201 * prints out actual debug level
1202 */
1203static int debug_prolog_level_fn(debug_info_t *id, struct debug_view *view,
1204 char *out_buf)
1205{
1206 int rc = 0;
1207
1208 if (id->level == DEBUG_OFF_LEVEL)
1209 rc = sprintf(out_buf, "-\n");
1210 else
1211 rc = sprintf(out_buf, "%i\n", id->level);
1212 return rc;
1213}
1214
1215/*
1216 * reads new debug level
1217 */
1218static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,
1219 struct file *file, const char __user *user_buf,
1220 size_t user_len, loff_t *offset)
1221{
1222 int rc, new_level;
1223 char *str;
1224
1225 if (user_len > 0x10000)
1226 user_len = 0x10000;
1227 if (*offset != 0) {
1228 rc = -EPIPE;
1229 goto out;
1230 }
1231 str = debug_get_user_string(user_buf, user_len);
1232 if (IS_ERR(str)) {
1233 rc = PTR_ERR(str);
1234 goto out;
1235 }
1236 if (str[0] == '-') {
1237 debug_set_level(id, DEBUG_OFF_LEVEL);
1238 rc = user_len;
1239 goto free_str;
1240 } else {
1241 new_level = debug_get_uint(str);
1242 }
1243 if (new_level < 0) {
1244 pr_warn("%s is not a valid level for a debug feature\n", str);
1245 rc = -EINVAL;
1246 } else {
1247 debug_set_level(id, new_level);
1248 rc = user_len;
1249 }
1250free_str:
1251 kfree(str);
1252out:
1253 *offset += user_len;
1254 return rc; /* number of input characters */
1255}
1256
1257/*
1258 * flushes debug areas
1259 */
1260static void debug_flush(debug_info_t *id, int area)
1261{
1262 unsigned long flags;
1263 int i, j;
1264
1265 if (!id || !id->areas)
1266 return;
1267 spin_lock_irqsave(&id->lock, flags);
1268 if (area == DEBUG_FLUSH_ALL) {
1269 id->active_area = 0;
1270 memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1271 for (i = 0; i < id->nr_areas; i++) {
1272 id->active_pages[i] = 0;
1273 for (j = 0; j < id->pages_per_area; j++)
1274 memset(id->areas[i][j], 0, PAGE_SIZE);
1275 }
1276 } else if (area >= 0 && area < id->nr_areas) {
1277 id->active_entries[area] = 0;
1278 id->active_pages[area] = 0;
1279 for (i = 0; i < id->pages_per_area; i++)
1280 memset(id->areas[area][i], 0, PAGE_SIZE);
1281 }
1282 spin_unlock_irqrestore(&id->lock, flags);
1283}
1284
1285/*
1286 * view function: flushes debug areas
1287 */
1288static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
1289 struct file *file, const char __user *user_buf,
1290 size_t user_len, loff_t *offset)
1291{
1292 char input_buf[1];
1293 int rc = user_len;
1294
1295 if (user_len > 0x10000)
1296 user_len = 0x10000;
1297 if (*offset != 0) {
1298 rc = -EPIPE;
1299 goto out;
1300 }
1301 if (copy_from_user(input_buf, user_buf, 1)) {
1302 rc = -EFAULT;
1303 goto out;
1304 }
1305 if (input_buf[0] == '-') {
1306 debug_flush(id, DEBUG_FLUSH_ALL);
1307 goto out;
1308 }
1309 if (isdigit(input_buf[0])) {
1310 int area = ((int) input_buf[0] - (int) '0');
1311
1312 debug_flush(id, area);
1313 goto out;
1314 }
1315
1316 pr_info("Flushing debug data failed because %c is not a valid "
1317 "area\n", input_buf[0]);
1318
1319out:
1320 *offset += user_len;
1321 return rc; /* number of input characters */
1322}
1323
1324/*
1325 * prints debug header in raw format
1326 */
1327static int debug_raw_header_fn(debug_info_t *id, struct debug_view *view,
1328 int area, debug_entry_t *entry, char *out_buf)
1329{
1330 int rc;
1331
1332 rc = sizeof(debug_entry_t);
1333 memcpy(out_buf, entry, sizeof(debug_entry_t));
1334 return rc;
1335}
1336
1337/*
1338 * prints debug data in raw format
1339 */
1340static int debug_raw_format_fn(debug_info_t *id, struct debug_view *view,
1341 char *out_buf, const char *in_buf)
1342{
1343 int rc;
1344
1345 rc = id->buf_size;
1346 memcpy(out_buf, in_buf, id->buf_size);
1347 return rc;
1348}
1349
1350/*
1351 * prints debug data in hex/ascii format
1352 */
1353static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
1354 char *out_buf, const char *in_buf)
1355{
1356 int i, rc = 0;
1357
1358 for (i = 0; i < id->buf_size; i++)
1359 rc += sprintf(out_buf + rc, "%02x ", ((unsigned char *) in_buf)[i]);
1360 rc += sprintf(out_buf + rc, "| ");
1361 for (i = 0; i < id->buf_size; i++) {
1362 unsigned char c = in_buf[i];
1363
1364 if (isascii(c) && isprint(c))
1365 rc += sprintf(out_buf + rc, "%c", c);
1366 else
1367 rc += sprintf(out_buf + rc, ".");
1368 }
1369 rc += sprintf(out_buf + rc, "\n");
1370 return rc;
1371}
1372
1373/*
1374 * prints header for debug entry
1375 */
1376int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
1377 int area, debug_entry_t *entry, char *out_buf)
1378{
1379 unsigned long base, sec, usec;
1380 unsigned long caller;
1381 unsigned int level;
1382 char *except_str;
1383 int rc = 0;
1384
1385 level = entry->id.fields.level;
1386 base = (*(unsigned long *) &tod_clock_base[0]) >> 4;
1387 sec = (entry->id.stck >> 12) + base - (TOD_UNIX_EPOCH >> 12);
1388 usec = do_div(sec, USEC_PER_SEC);
1389
1390 if (entry->id.fields.exception)
1391 except_str = "*";
1392 else
1393 except_str = "-";
1394 caller = (unsigned long) entry->caller;
1395 rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %02i %pK ",
1396 area, sec, usec, level, except_str,
1397 entry->id.fields.cpuid, (void *)caller);
1398 return rc;
1399}
1400EXPORT_SYMBOL(debug_dflt_header_fn);
1401
1402/*
1403 * prints debug data sprintf-formated:
1404 * debug_sprinf_event/exception calls must be used together with this view
1405 */
1406
1407#define DEBUG_SPRINTF_MAX_ARGS 10
1408
1409static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
1410 char *out_buf, debug_sprintf_entry_t *curr_event)
1411{
1412 int num_longs, num_used_args = 0, i, rc = 0;
1413 int index[DEBUG_SPRINTF_MAX_ARGS];
1414
1415 /* count of longs fit into one entry */
1416 num_longs = id->buf_size / sizeof(long);
1417
1418 if (num_longs < 1)
1419 goto out; /* bufsize of entry too small */
1420 if (num_longs == 1) {
1421 /* no args, we use only the string */
1422 strcpy(out_buf, curr_event->string);
1423 rc = strlen(curr_event->string);
1424 goto out;
1425 }
1426
1427 /* number of arguments used for sprintf (without the format string) */
1428 num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1429
1430 memset(index, 0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1431
1432 for (i = 0; i < num_used_args; i++)
1433 index[i] = i;
1434
1435 rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1436 curr_event->args[index[1]], curr_event->args[index[2]],
1437 curr_event->args[index[3]], curr_event->args[index[4]],
1438 curr_event->args[index[5]], curr_event->args[index[6]],
1439 curr_event->args[index[7]], curr_event->args[index[8]],
1440 curr_event->args[index[9]]);
1441out:
1442 return rc;
1443}
1444
1445/*
1446 * debug_init:
1447 * - is called exactly once to initialize the debug feature
1448 */
1449static int __init debug_init(void)
1450{
1451 s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
1452 mutex_lock(&debug_mutex);
1453 debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT, NULL);
1454 initialized = 1;
1455 mutex_unlock(&debug_mutex);
1456 return 0;
1457}
1458postcore_initcall(debug_init);