Root/arch/s390/kernel/debug.c

1/*
2 * arch/s390/kernel/debug.c
3 * S/390 debug facility
4 *
5 * Copyright (C) 1999, 2000 IBM Deutschland Entwicklung GmbH,
6 * IBM Corporation
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 <asm/uaccess.h>
24#include <linux/module.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{
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
67/* internal function prototyes */
68
69static int debug_init(void);
70static ssize_t debug_output(struct file *file, char __user *user_buf,
71            size_t user_len, loff_t * offset);
72static ssize_t debug_input(struct file *file, const char __user *user_buf,
73            size_t user_len, loff_t * offset);
74static int debug_open(struct inode *inode, struct file *file);
75static int debug_close(struct inode *inode, struct file *file);
76static debug_info_t *debug_info_create(const char *name, int pages_per_area,
77            int nr_areas, int buf_size, mode_t mode);
78static void debug_info_get(debug_info_t *);
79static void debug_info_put(debug_info_t *);
80static int debug_prolog_level_fn(debug_info_t * id,
81            struct debug_view *view, char *out_buf);
82static int debug_input_level_fn(debug_info_t * id, struct debug_view *view,
83            struct file *file, const char __user *user_buf,
84            size_t user_buf_size, loff_t * offset);
85static int debug_prolog_pages_fn(debug_info_t * id,
86            struct debug_view *view, char *out_buf);
87static int debug_input_pages_fn(debug_info_t * id, struct debug_view *view,
88            struct file *file, const char __user *user_buf,
89            size_t user_buf_size, loff_t * offset);
90static int debug_input_flush_fn(debug_info_t * id, struct debug_view *view,
91            struct file *file, const char __user *user_buf,
92            size_t user_buf_size, loff_t * offset);
93static int debug_hex_ascii_format_fn(debug_info_t * id, struct debug_view *view,
94            char *out_buf, const char *in_buf);
95static int debug_raw_format_fn(debug_info_t * id,
96            struct debug_view *view, char *out_buf,
97            const char *in_buf);
98static int debug_raw_header_fn(debug_info_t * id, struct debug_view *view,
99            int area, debug_entry_t * entry, char *out_buf);
100
101static int debug_sprintf_format_fn(debug_info_t * id, struct debug_view *view,
102            char *out_buf, debug_sprintf_entry_t *curr_event);
103
104/* globals */
105
106struct debug_view debug_raw_view = {
107    "raw",
108    NULL,
109    &debug_raw_header_fn,
110    &debug_raw_format_fn,
111    NULL,
112    NULL
113};
114
115struct debug_view debug_hex_ascii_view = {
116    "hex_ascii",
117    NULL,
118    &debug_dflt_header_fn,
119    &debug_hex_ascii_format_fn,
120    NULL,
121    NULL
122};
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};
159
160/* used by dump analysis tools to determine version of debug feature */
161static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION;
162
163/* static globals */
164
165static debug_info_t *debug_area_first = NULL;
166static debug_info_t *debug_area_last = NULL;
167static DEFINE_MUTEX(debug_mutex);
168
169static int initialized;
170
171static const struct file_operations debug_file_ops = {
172    .owner = THIS_MODULE,
173    .read = debug_output,
174    .write = debug_input,
175    .open = debug_open,
176    .release = debug_close,
177    .llseek = no_llseek,
178};
179
180static struct dentry *debug_debugfs_root_entry;
181
182/* functions */
183
184/*
185 * debug_areas_alloc
186 * - Debug areas are implemented as a threedimensonal array:
187 * areas[areanumber][pagenumber][pageoffset]
188 */
189
190static debug_entry_t***
191debug_areas_alloc(int pages_per_area, int nr_areas)
192{
193    debug_entry_t*** areas;
194    int i,j;
195
196    areas = kmalloc(nr_areas *
197                    sizeof(debug_entry_t**),
198                    GFP_KERNEL);
199    if (!areas)
200        goto fail_malloc_areas;
201    for (i = 0; i < nr_areas; i++) {
202        areas[i] = kmalloc(pages_per_area *
203                sizeof(debug_entry_t*),GFP_KERNEL);
204        if (!areas[i]) {
205            goto fail_malloc_areas2;
206        }
207        for(j = 0; j < pages_per_area; j++) {
208            areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);
209            if(!areas[i][j]) {
210                for(j--; j >=0 ; j--) {
211                    kfree(areas[i][j]);
212                }
213                kfree(areas[i]);
214                goto fail_malloc_areas2;
215            }
216        }
217    }
218    return areas;
219
220fail_malloc_areas2:
221    for(i--; i >= 0; i--){
222        for(j=0; j < pages_per_area;j++){
223            kfree(areas[i][j]);
224        }
225        kfree(areas[i]);
226    }
227    kfree(areas);
228fail_malloc_areas:
229    return NULL;
230
231}
232
233
234/*
235 * debug_info_alloc
236 * - alloc new debug-info
237 */
238
239static debug_info_t*
240debug_info_alloc(const char *name, int pages_per_area, int nr_areas,
241         int buf_size, int level, int mode)
242{
243    debug_info_t* rc;
244
245    /* alloc everything */
246
247    rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);
248    if(!rc)
249        goto fail_malloc_rc;
250    rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
251    if(!rc->active_entries)
252        goto fail_malloc_active_entries;
253    rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);
254    if(!rc->active_pages)
255        goto fail_malloc_active_pages;
256    if((mode == ALL_AREAS) && (pages_per_area != 0)){
257        rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
258        if(!rc->areas)
259            goto fail_malloc_areas;
260    } else {
261        rc->areas = NULL;
262    }
263
264    /* initialize members */
265
266    spin_lock_init(&rc->lock);
267    rc->pages_per_area = pages_per_area;
268    rc->nr_areas = nr_areas;
269    rc->active_area = 0;
270    rc->level = level;
271    rc->buf_size = buf_size;
272    rc->entry_size = sizeof(debug_entry_t) + buf_size;
273    strlcpy(rc->name, name, sizeof(rc->name));
274    memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
275    memset(rc->debugfs_entries, 0 ,DEBUG_MAX_VIEWS *
276        sizeof(struct dentry*));
277    atomic_set(&(rc->ref_count), 0);
278
279    return rc;
280
281fail_malloc_areas:
282    kfree(rc->active_pages);
283fail_malloc_active_pages:
284    kfree(rc->active_entries);
285fail_malloc_active_entries:
286    kfree(rc);
287fail_malloc_rc:
288    return NULL;
289}
290
291/*
292 * debug_areas_free
293 * - free all debug areas
294 */
295
296static void
297debug_areas_free(debug_info_t* db_info)
298{
299    int i,j;
300
301    if(!db_info->areas)
302        return;
303    for (i = 0; i < db_info->nr_areas; i++) {
304        for(j = 0; j < db_info->pages_per_area; j++) {
305            kfree(db_info->areas[i][j]);
306        }
307        kfree(db_info->areas[i]);
308    }
309    kfree(db_info->areas);
310    db_info->areas = NULL;
311}
312
313/*
314 * debug_info_free
315 * - free memory debug-info
316 */
317
318static void
319debug_info_free(debug_info_t* db_info){
320    debug_areas_free(db_info);
321    kfree(db_info->active_entries);
322    kfree(db_info->active_pages);
323    kfree(db_info);
324}
325
326/*
327 * debug_info_create
328 * - create new debug-info
329 */
330
331static debug_info_t*
332debug_info_create(const char *name, int pages_per_area, int nr_areas,
333          int buf_size, mode_t mode)
334{
335    debug_info_t* rc;
336
337        rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
338                DEBUG_DEFAULT_LEVEL, ALL_AREAS);
339        if(!rc)
340        goto out;
341
342    rc->mode = mode & ~S_IFMT;
343
344    /* create root directory */
345        rc->debugfs_root_entry = debugfs_create_dir(rc->name,
346                    debug_debugfs_root_entry);
347
348    /* append new element to linked list */
349        if (!debug_area_first) {
350                /* first element in list */
351                debug_area_first = rc;
352                rc->prev = NULL;
353        } else {
354                /* append element to end of list */
355                debug_area_last->next = rc;
356                rc->prev = debug_area_last;
357        }
358        debug_area_last = rc;
359        rc->next = NULL;
360
361    debug_info_get(rc);
362out:
363    return rc;
364}
365
366/*
367 * debug_info_copy
368 * - copy debug-info
369 */
370
371static debug_info_t*
372debug_info_copy(debug_info_t* in, int mode)
373{
374        int i,j;
375        debug_info_t* rc;
376        unsigned long flags;
377
378    /* get a consistent copy of the debug areas */
379    do {
380        rc = debug_info_alloc(in->name, in->pages_per_area,
381            in->nr_areas, in->buf_size, in->level, mode);
382        spin_lock_irqsave(&in->lock, flags);
383        if(!rc)
384            goto out;
385        /* has something changed in the meantime ? */
386        if((rc->pages_per_area == in->pages_per_area) &&
387           (rc->nr_areas == in->nr_areas)) {
388            break;
389        }
390        spin_unlock_irqrestore(&in->lock, flags);
391        debug_info_free(rc);
392    } while (1);
393
394    if (mode == NO_AREAS)
395                goto out;
396
397        for(i = 0; i < in->nr_areas; i++){
398        for(j = 0; j < in->pages_per_area; j++) {
399            memcpy(rc->areas[i][j], in->areas[i][j],PAGE_SIZE);
400        }
401        }
402out:
403        spin_unlock_irqrestore(&in->lock, flags);
404        return rc;
405}
406
407/*
408 * debug_info_get
409 * - increments reference count for debug-info
410 */
411
412static void
413debug_info_get(debug_info_t * db_info)
414{
415    if (db_info)
416        atomic_inc(&db_info->ref_count);
417}
418
419/*
420 * debug_info_put:
421 * - decreases reference count for debug-info and frees it if necessary
422 */
423
424static void
425debug_info_put(debug_info_t *db_info)
426{
427    int i;
428
429    if (!db_info)
430        return;
431    if (atomic_dec_and_test(&db_info->ref_count)) {
432        for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
433            if (!db_info->views[i])
434                continue;
435            debugfs_remove(db_info->debugfs_entries[i]);
436        }
437        debugfs_remove(db_info->debugfs_root_entry);
438        if(db_info == debug_area_first)
439            debug_area_first = db_info->next;
440        if(db_info == debug_area_last)
441            debug_area_last = db_info->prev;
442        if(db_info->prev) db_info->prev->next = db_info->next;
443        if(db_info->next) db_info->next->prev = db_info->prev;
444        debug_info_free(db_info);
445    }
446}
447
448/*
449 * debug_format_entry:
450 * - format one debug entry and return size of formated data
451 */
452
453static int
454debug_format_entry(file_private_info_t *p_info)
455{
456    debug_info_t *id_snap = p_info->debug_info_snap;
457    struct debug_view *view = p_info->view;
458    debug_entry_t *act_entry;
459    size_t len = 0;
460    if(p_info->act_entry == DEBUG_PROLOG_ENTRY){
461        /* print prolog */
462            if (view->prolog_proc)
463                    len += view->prolog_proc(id_snap,view,p_info->temp_buf);
464        goto out;
465    }
466    if (!id_snap->areas) /* this is true, if we have a prolog only view */
467        goto out; /* or if 'pages_per_area' is 0 */
468    act_entry = (debug_entry_t *) ((char*)id_snap->areas[p_info->act_area]
469                [p_info->act_page] + p_info->act_entry);
470                        
471    if (act_entry->id.stck == 0LL)
472            goto out; /* empty entry */
473    if (view->header_proc)
474        len += view->header_proc(id_snap, view, p_info->act_area,
475                    act_entry, p_info->temp_buf + len);
476    if (view->format_proc)
477        len += view->format_proc(id_snap, view, p_info->temp_buf + len,
478                        DEBUG_DATA(act_entry));
479out:
480        return len;
481}
482
483/*
484 * debug_next_entry:
485 * - goto next entry in p_info
486 */
487
488static inline int
489debug_next_entry(file_private_info_t *p_info)
490{
491    debug_info_t *id;
492
493    id = p_info->debug_info_snap;
494    if(p_info->act_entry == DEBUG_PROLOG_ENTRY){
495        p_info->act_entry = 0;
496        p_info->act_page = 0;
497        goto out;
498    }
499    if(!id->areas)
500        return 1;
501    p_info->act_entry += id->entry_size;
502    /* switch to next page, if we reached the end of the page */
503    if (p_info->act_entry > (PAGE_SIZE - id->entry_size)){
504        /* next page */
505        p_info->act_entry = 0;
506        p_info->act_page += 1;
507        if((p_info->act_page % id->pages_per_area) == 0) {
508            /* next area */
509                p_info->act_area++;
510            p_info->act_page=0;
511        }
512            if(p_info->act_area >= id->nr_areas)
513            return 1;
514    }
515out:
516    return 0;
517}
518
519/*
520 * debug_output:
521 * - called for user read()
522 * - copies formated debug entries to the user buffer
523 */
524
525static ssize_t
526debug_output(struct file *file, /* file descriptor */
527        char __user *user_buf, /* user buffer */
528        size_t len, /* length of buffer */
529        loff_t *offset) /* offset in the file */
530{
531    size_t count = 0;
532    size_t entry_offset;
533    file_private_info_t *p_info;
534
535    p_info = ((file_private_info_t *) file->private_data);
536    if (*offset != p_info->offset)
537        return -EPIPE;
538    if(p_info->act_area >= p_info->debug_info_snap->nr_areas)
539        return 0;
540    entry_offset = p_info->act_entry_offset;
541    while(count < len){
542        int formatted_line_size;
543        int formatted_line_residue;
544        int user_buf_residue;
545        size_t copy_size;
546
547        formatted_line_size = debug_format_entry(p_info);
548        formatted_line_residue = formatted_line_size - entry_offset;
549        user_buf_residue = len-count;
550        copy_size = min(user_buf_residue, formatted_line_residue);
551        if(copy_size){
552            if (copy_to_user(user_buf + count, p_info->temp_buf
553                    + entry_offset, copy_size))
554                return -EFAULT;
555            count += copy_size;
556            entry_offset += copy_size;
557        }
558        if(copy_size == formatted_line_residue){
559            entry_offset = 0;
560            if(debug_next_entry(p_info))
561                goto out;
562        }
563    }
564out:
565    p_info->offset = *offset + count;
566    p_info->act_entry_offset = entry_offset;
567    *offset = p_info->offset;
568    return count;
569}
570
571/*
572 * debug_input:
573 * - called for user write()
574 * - calls input function of view
575 */
576
577static ssize_t
578debug_input(struct file *file, const char __user *user_buf, size_t length,
579        loff_t *offset)
580{
581    int rc = 0;
582    file_private_info_t *p_info;
583
584    mutex_lock(&debug_mutex);
585    p_info = ((file_private_info_t *) file->private_data);
586    if (p_info->view->input_proc)
587        rc = p_info->view->input_proc(p_info->debug_info_org,
588                          p_info->view, file, user_buf,
589                          length, offset);
590    else
591        rc = -EPERM;
592    mutex_unlock(&debug_mutex);
593    return rc; /* number of input characters */
594}
595
596/*
597 * debug_open:
598 * - called for user open()
599 * - copies formated output to private_data area of the file
600 * handle
601 */
602
603static int
604debug_open(struct inode *inode, struct file *file)
605{
606    int i, rc = 0;
607    file_private_info_t *p_info;
608    debug_info_t *debug_info, *debug_info_snapshot;
609
610    mutex_lock(&debug_mutex);
611    debug_info = file->f_path.dentry->d_inode->i_private;
612    /* find debug view */
613    for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
614        if (!debug_info->views[i])
615            continue;
616        else if (debug_info->debugfs_entries[i] ==
617             file->f_path.dentry) {
618            goto found; /* found view ! */
619        }
620    }
621    /* no entry found */
622    rc = -EINVAL;
623    goto out;
624
625found:
626
627    /* Make snapshot of current debug areas to get it consistent. */
628    /* To copy all the areas is only needed, if we have a view which */
629    /* formats the debug areas. */
630
631    if(!debug_info->views[i]->format_proc &&
632        !debug_info->views[i]->header_proc){
633        debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
634    } else {
635        debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
636    }
637
638    if(!debug_info_snapshot){
639        rc = -ENOMEM;
640        goto out;
641    }
642    p_info = kmalloc(sizeof(file_private_info_t),
643                        GFP_KERNEL);
644    if(!p_info){
645        debug_info_free(debug_info_snapshot);
646        rc = -ENOMEM;
647        goto out;
648    }
649    p_info->offset = 0;
650    p_info->debug_info_snap = debug_info_snapshot;
651    p_info->debug_info_org = debug_info;
652    p_info->view = debug_info->views[i];
653    p_info->act_area = 0;
654    p_info->act_page = 0;
655    p_info->act_entry = DEBUG_PROLOG_ENTRY;
656    p_info->act_entry_offset = 0;
657    file->private_data = p_info;
658    debug_info_get(debug_info);
659    nonseekable_open(inode, file);
660out:
661    mutex_unlock(&debug_mutex);
662    return rc;
663}
664
665/*
666 * debug_close:
667 * - called for user close()
668 * - deletes private_data area of the file handle
669 */
670
671static int
672debug_close(struct inode *inode, struct file *file)
673{
674    file_private_info_t *p_info;
675    p_info = (file_private_info_t *) file->private_data;
676    if(p_info->debug_info_snap)
677        debug_info_free(p_info->debug_info_snap);
678    debug_info_put(p_info->debug_info_org);
679    kfree(file->private_data);
680    return 0; /* success */
681}
682
683/*
684 * debug_register_mode:
685 * - Creates and initializes debug area for the caller
686 * The mode parameter allows to specify access rights for the s390dbf files
687 * - Returns handle for debug area
688 */
689
690debug_info_t *debug_register_mode(const char *name, int pages_per_area,
691                  int nr_areas, int buf_size, mode_t mode,
692                  uid_t uid, gid_t gid)
693{
694    debug_info_t *rc = NULL;
695
696    /* Since debugfs currently does not support uid/gid other than root, */
697    /* we do not allow gid/uid != 0 until we get support for that. */
698    if ((uid != 0) || (gid != 0))
699        pr_warning("Root becomes the owner of all s390dbf files "
700               "in sysfs\n");
701    BUG_ON(!initialized);
702    mutex_lock(&debug_mutex);
703
704        /* create new debug_info */
705
706    rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
707    if(!rc)
708        goto out;
709    debug_register_view(rc, &debug_level_view);
710        debug_register_view(rc, &debug_flush_view);
711    debug_register_view(rc, &debug_pages_view);
712out:
713        if (!rc){
714        pr_err("Registering debug feature %s failed\n", name);
715        }
716    mutex_unlock(&debug_mutex);
717    return rc;
718}
719EXPORT_SYMBOL(debug_register_mode);
720
721/*
722 * debug_register:
723 * - creates and initializes debug area for the caller
724 * - returns handle for debug area
725 */
726
727debug_info_t *debug_register(const char *name, int pages_per_area,
728                 int nr_areas, int buf_size)
729{
730    return debug_register_mode(name, pages_per_area, nr_areas, buf_size,
731                   S_IRUSR | S_IWUSR, 0, 0);
732}
733
734/*
735 * debug_unregister:
736 * - give back debug area
737 */
738
739void
740debug_unregister(debug_info_t * id)
741{
742    if (!id)
743        goto out;
744    mutex_lock(&debug_mutex);
745    debug_info_put(id);
746    mutex_unlock(&debug_mutex);
747
748out:
749    return;
750}
751
752/*
753 * debug_set_size:
754 * - set area size (number of pages) and number of areas
755 */
756static int
757debug_set_size(debug_info_t* id, int nr_areas, int pages_per_area)
758{
759    unsigned long flags;
760    debug_entry_t *** new_areas;
761    int rc=0;
762
763    if(!id || (nr_areas <= 0) || (pages_per_area < 0))
764        return -EINVAL;
765    if(pages_per_area > 0){
766        new_areas = debug_areas_alloc(pages_per_area, nr_areas);
767        if(!new_areas) {
768            pr_info("Allocating memory for %i pages failed\n",
769                pages_per_area);
770            rc = -ENOMEM;
771            goto out;
772        }
773    } else {
774        new_areas = NULL;
775    }
776    spin_lock_irqsave(&id->lock,flags);
777    debug_areas_free(id);
778    id->areas = new_areas;
779    id->nr_areas = nr_areas;
780    id->pages_per_area = pages_per_area;
781    id->active_area = 0;
782    memset(id->active_entries,0,sizeof(int)*id->nr_areas);
783    memset(id->active_pages, 0, sizeof(int)*id->nr_areas);
784    spin_unlock_irqrestore(&id->lock,flags);
785    pr_info("%s: set new size (%i pages)\n" ,id->name, pages_per_area);
786out:
787    return rc;
788}
789
790/*
791 * debug_set_level:
792 * - set actual debug level
793 */
794
795void
796debug_set_level(debug_info_t* id, int new_level)
797{
798    unsigned long flags;
799    if(!id)
800        return;
801    spin_lock_irqsave(&id->lock,flags);
802        if(new_level == DEBUG_OFF_LEVEL){
803                id->level = DEBUG_OFF_LEVEL;
804        pr_info("%s: switched off\n",id->name);
805        } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
806        pr_info("%s: level %i is out of range (%i - %i)\n",
807                        id->name, new_level, 0, DEBUG_MAX_LEVEL);
808        } else {
809                id->level = new_level;
810        }
811    spin_unlock_irqrestore(&id->lock,flags);
812}
813
814
815/*
816 * proceed_active_entry:
817 * - set active entry to next in the ring buffer
818 */
819
820static inline void
821proceed_active_entry(debug_info_t * id)
822{
823    if ((id->active_entries[id->active_area] += id->entry_size)
824        > (PAGE_SIZE - id->entry_size)){
825        id->active_entries[id->active_area] = 0;
826        id->active_pages[id->active_area] =
827            (id->active_pages[id->active_area] + 1) %
828            id->pages_per_area;
829    }
830}
831
832/*
833 * proceed_active_area:
834 * - set active area to next in the ring buffer
835 */
836
837static inline void
838proceed_active_area(debug_info_t * id)
839{
840    id->active_area++;
841    id->active_area = id->active_area % id->nr_areas;
842}
843
844/*
845 * get_active_entry:
846 */
847
848static inline debug_entry_t*
849get_active_entry(debug_info_t * id)
850{
851    return (debug_entry_t *) (((char *) id->areas[id->active_area]
852                    [id->active_pages[id->active_area]]) +
853                    id->active_entries[id->active_area]);
854}
855
856/*
857 * debug_finish_entry:
858 * - set timestamp, caller address, cpu number etc.
859 */
860
861static inline void
862debug_finish_entry(debug_info_t * id, debug_entry_t* active, int level,
863            int exception)
864{
865    active->id.stck = get_clock();
866    active->id.fields.cpuid = smp_processor_id();
867    active->caller = __builtin_return_address(0);
868    active->id.fields.exception = exception;
869    active->id.fields.level = level;
870    proceed_active_entry(id);
871    if(exception)
872        proceed_active_area(id);
873}
874
875static int debug_stoppable=1;
876static int debug_active=1;
877
878#define CTL_S390DBF_STOPPABLE 5678
879#define CTL_S390DBF_ACTIVE 5679
880
881/*
882 * proc handler for the running debug_active sysctl
883 * always allow read, allow write only if debug_stoppable is set or
884 * if debug_active is already off
885 */
886static int
887s390dbf_procactive(ctl_table *table, int write,
888                     void __user *buffer, size_t *lenp, loff_t *ppos)
889{
890    if (!write || debug_stoppable || !debug_active)
891        return proc_dointvec(table, write, buffer, lenp, ppos);
892    else
893        return 0;
894}
895
896
897static struct ctl_table s390dbf_table[] = {
898    {
899        .procname = "debug_stoppable",
900        .data = &debug_stoppable,
901        .maxlen = sizeof(int),
902        .mode = S_IRUGO | S_IWUSR,
903        .proc_handler = proc_dointvec,
904    },
905     {
906        .procname = "debug_active",
907        .data = &debug_active,
908        .maxlen = sizeof(int),
909        .mode = S_IRUGO | S_IWUSR,
910        .proc_handler = s390dbf_procactive,
911    },
912    { }
913};
914
915static struct ctl_table s390dbf_dir_table[] = {
916    {
917        .procname = "s390dbf",
918        .maxlen = 0,
919        .mode = S_IRUGO | S_IXUGO,
920        .child = s390dbf_table,
921    },
922    { }
923};
924
925static struct ctl_table_header *s390dbf_sysctl_header;
926
927void
928debug_stop_all(void)
929{
930    if (debug_stoppable)
931        debug_active = 0;
932}
933
934
935/*
936 * debug_event_common:
937 * - write debug entry with given size
938 */
939
940debug_entry_t*
941debug_event_common(debug_info_t * id, int level, const void *buf, int len)
942{
943    unsigned long flags;
944    debug_entry_t *active;
945
946    if (!debug_active || !id->areas)
947        return NULL;
948    spin_lock_irqsave(&id->lock, flags);
949    active = get_active_entry(id);
950    memset(DEBUG_DATA(active), 0, id->buf_size);
951    memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
952    debug_finish_entry(id, active, level, 0);
953    spin_unlock_irqrestore(&id->lock, flags);
954
955    return active;
956}
957
958/*
959 * debug_exception_common:
960 * - write debug entry with given size and switch to next debug area
961 */
962
963debug_entry_t
964*debug_exception_common(debug_info_t * id, int level, const void *buf, int len)
965{
966    unsigned long flags;
967    debug_entry_t *active;
968
969    if (!debug_active || !id->areas)
970        return NULL;
971    spin_lock_irqsave(&id->lock, flags);
972    active = get_active_entry(id);
973    memset(DEBUG_DATA(active), 0, id->buf_size);
974    memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
975    debug_finish_entry(id, active, level, 1);
976    spin_unlock_irqrestore(&id->lock, flags);
977
978    return active;
979}
980
981/*
982 * counts arguments in format string for sprintf view
983 */
984
985static inline int
986debug_count_numargs(char *string)
987{
988    int numargs=0;
989
990    while(*string) {
991        if(*string++=='%')
992            numargs++;
993    }
994    return(numargs);
995}
996
997/*
998 * debug_sprintf_event:
999 */
1000
1001debug_entry_t*
1002debug_sprintf_event(debug_info_t* id, int level,char *string,...)
1003{
1004    va_list ap;
1005    int numargs,idx;
1006    unsigned long flags;
1007    debug_sprintf_entry_t *curr_event;
1008    debug_entry_t *active;
1009
1010    if((!id) || (level > id->level))
1011        return NULL;
1012    if (!debug_active || !id->areas)
1013        return NULL;
1014    numargs=debug_count_numargs(string);
1015
1016    spin_lock_irqsave(&id->lock, flags);
1017    active = get_active_entry(id);
1018    curr_event=(debug_sprintf_entry_t *) DEBUG_DATA(active);
1019    va_start(ap,string);
1020    curr_event->string=string;
1021    for(idx=0;idx<min(numargs,(int)(id->buf_size / sizeof(long))-1);idx++)
1022        curr_event->args[idx]=va_arg(ap,long);
1023    va_end(ap);
1024    debug_finish_entry(id, active, level, 0);
1025    spin_unlock_irqrestore(&id->lock, flags);
1026
1027    return active;
1028}
1029
1030/*
1031 * debug_sprintf_exception:
1032 */
1033
1034debug_entry_t*
1035debug_sprintf_exception(debug_info_t* id, int level,char *string,...)
1036{
1037    va_list ap;
1038    int numargs,idx;
1039    unsigned long flags;
1040    debug_sprintf_entry_t *curr_event;
1041    debug_entry_t *active;
1042
1043    if((!id) || (level > id->level))
1044        return NULL;
1045    if (!debug_active || !id->areas)
1046        return NULL;
1047
1048    numargs=debug_count_numargs(string);
1049
1050    spin_lock_irqsave(&id->lock, flags);
1051    active = get_active_entry(id);
1052    curr_event=(debug_sprintf_entry_t *)DEBUG_DATA(active);
1053    va_start(ap,string);
1054    curr_event->string=string;
1055    for(idx=0;idx<min(numargs,(int)(id->buf_size / sizeof(long))-1);idx++)
1056        curr_event->args[idx]=va_arg(ap,long);
1057    va_end(ap);
1058    debug_finish_entry(id, active, level, 1);
1059    spin_unlock_irqrestore(&id->lock, flags);
1060
1061    return active;
1062}
1063
1064/*
1065 * debug_init:
1066 * - is called exactly once to initialize the debug feature
1067 */
1068
1069static int
1070__init debug_init(void)
1071{
1072    int rc = 0;
1073
1074    s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
1075    mutex_lock(&debug_mutex);
1076    debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT,NULL);
1077    initialized = 1;
1078    mutex_unlock(&debug_mutex);
1079
1080    return rc;
1081}
1082
1083/*
1084 * debug_register_view:
1085 */
1086
1087int
1088debug_register_view(debug_info_t * id, struct debug_view *view)
1089{
1090    int rc = 0;
1091    int i;
1092    unsigned long flags;
1093    mode_t mode;
1094    struct dentry *pde;
1095
1096    if (!id)
1097        goto out;
1098    mode = (id->mode | S_IFREG) & ~S_IXUGO;
1099    if (!(view->prolog_proc || view->format_proc || view->header_proc))
1100        mode &= ~(S_IRUSR | S_IRGRP | S_IROTH);
1101    if (!view->input_proc)
1102        mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
1103    pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
1104                id , &debug_file_ops);
1105    if (!pde){
1106        pr_err("Registering view %s/%s failed due to out of "
1107               "memory\n", id->name,view->name);
1108        rc = -1;
1109        goto out;
1110    }
1111    spin_lock_irqsave(&id->lock, flags);
1112    for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1113        if (!id->views[i])
1114            break;
1115    }
1116    if (i == DEBUG_MAX_VIEWS) {
1117        pr_err("Registering view %s/%s would exceed the maximum "
1118               "number of views %i\n", id->name, view->name, i);
1119        debugfs_remove(pde);
1120        rc = -1;
1121    } else {
1122        id->views[i] = view;
1123        id->debugfs_entries[i] = pde;
1124    }
1125    spin_unlock_irqrestore(&id->lock, flags);
1126out:
1127    return rc;
1128}
1129
1130/*
1131 * debug_unregister_view:
1132 */
1133
1134int
1135debug_unregister_view(debug_info_t * id, struct debug_view *view)
1136{
1137    int rc = 0;
1138    int i;
1139    unsigned long flags;
1140
1141    if (!id)
1142        goto out;
1143    spin_lock_irqsave(&id->lock, flags);
1144    for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
1145        if (id->views[i] == view)
1146            break;
1147    }
1148    if (i == DEBUG_MAX_VIEWS)
1149        rc = -1;
1150    else {
1151        debugfs_remove(id->debugfs_entries[i]);
1152        id->views[i] = NULL;
1153    }
1154    spin_unlock_irqrestore(&id->lock, flags);
1155out:
1156    return rc;
1157}
1158
1159static inline char *
1160debug_get_user_string(const char __user *user_buf, size_t user_len)
1161{
1162    char* buffer;
1163
1164    buffer = kmalloc(user_len + 1, GFP_KERNEL);
1165    if (!buffer)
1166        return ERR_PTR(-ENOMEM);
1167    if (copy_from_user(buffer, user_buf, user_len) != 0) {
1168        kfree(buffer);
1169        return ERR_PTR(-EFAULT);
1170    }
1171    /* got the string, now strip linefeed. */
1172    if (buffer[user_len - 1] == '\n')
1173        buffer[user_len - 1] = 0;
1174    else
1175        buffer[user_len] = 0;
1176        return buffer;
1177}
1178
1179static inline int
1180debug_get_uint(char *buf)
1181{
1182    int rc;
1183
1184    buf = skip_spaces(buf);
1185    rc = simple_strtoul(buf, &buf, 10);
1186    if(*buf){
1187        rc = -EINVAL;
1188    }
1189    return rc;
1190}
1191
1192/*
1193 * functions for debug-views
1194 ***********************************
1195*/
1196
1197/*
1198 * prints out actual debug level
1199 */
1200
1201static int
1202debug_prolog_pages_fn(debug_info_t * id,
1203                 struct debug_view *view, char *out_buf)
1204{
1205    return sprintf(out_buf, "%i\n", id->pages_per_area);
1206}
1207
1208/*
1209 * reads new size (number of pages per debug area)
1210 */
1211
1212static int
1213debug_input_pages_fn(debug_info_t * id, struct debug_view *view,
1214            struct file *file, const char __user *user_buf,
1215            size_t user_len, loff_t * offset)
1216{
1217    char *str;
1218    int rc,new_pages;
1219
1220    if (user_len > 0x10000)
1221                user_len = 0x10000;
1222    if (*offset != 0){
1223        rc = -EPIPE;
1224        goto out;
1225    }
1226    str = debug_get_user_string(user_buf,user_len);
1227    if(IS_ERR(str)){
1228        rc = PTR_ERR(str);
1229        goto out;
1230    }
1231    new_pages = debug_get_uint(str);
1232    if(new_pages < 0){
1233        rc = -EINVAL;
1234        goto free_str;
1235    }
1236    rc = debug_set_size(id,id->nr_areas, new_pages);
1237    if(rc != 0){
1238        rc = -EINVAL;
1239        goto free_str;
1240    }
1241    rc = user_len;
1242free_str:
1243    kfree(str);
1244out:
1245    *offset += user_len;
1246    return rc; /* number of input characters */
1247}
1248
1249/*
1250 * prints out actual debug level
1251 */
1252
1253static int
1254debug_prolog_level_fn(debug_info_t * id, struct debug_view *view, char *out_buf)
1255{
1256    int rc = 0;
1257
1258    if(id->level == DEBUG_OFF_LEVEL) {
1259        rc = sprintf(out_buf,"-\n");
1260    }
1261    else {
1262        rc = sprintf(out_buf, "%i\n", id->level);
1263    }
1264    return rc;
1265}
1266
1267/*
1268 * reads new debug level
1269 */
1270
1271static int
1272debug_input_level_fn(debug_info_t * id, struct debug_view *view,
1273            struct file *file, const char __user *user_buf,
1274            size_t user_len, loff_t * offset)
1275{
1276    char *str;
1277    int rc,new_level;
1278
1279    if (user_len > 0x10000)
1280                user_len = 0x10000;
1281    if (*offset != 0){
1282        rc = -EPIPE;
1283        goto out;
1284    }
1285    str = debug_get_user_string(user_buf,user_len);
1286    if(IS_ERR(str)){
1287        rc = PTR_ERR(str);
1288        goto out;
1289    }
1290    if(str[0] == '-'){
1291        debug_set_level(id, DEBUG_OFF_LEVEL);
1292        rc = user_len;
1293        goto free_str;
1294    } else {
1295        new_level = debug_get_uint(str);
1296    }
1297    if(new_level < 0) {
1298        pr_warning("%s is not a valid level for a debug "
1299               "feature\n", str);
1300        rc = -EINVAL;
1301    } else {
1302        debug_set_level(id, new_level);
1303        rc = user_len;
1304    }
1305free_str:
1306    kfree(str);
1307out:
1308    *offset += user_len;
1309    return rc; /* number of input characters */
1310}
1311
1312
1313/*
1314 * flushes debug areas
1315 */
1316 
1317static void debug_flush(debug_info_t* id, int area)
1318{
1319        unsigned long flags;
1320        int i,j;
1321
1322        if(!id || !id->areas)
1323                return;
1324        spin_lock_irqsave(&id->lock,flags);
1325        if(area == DEBUG_FLUSH_ALL){
1326                id->active_area = 0;
1327                memset(id->active_entries, 0, id->nr_areas * sizeof(int));
1328                for (i = 0; i < id->nr_areas; i++) {
1329            id->active_pages[i] = 0;
1330            for(j = 0; j < id->pages_per_area; j++) {
1331                            memset(id->areas[i][j], 0, PAGE_SIZE);
1332            }
1333        }
1334        } else if(area >= 0 && area < id->nr_areas) {
1335                id->active_entries[area] = 0;
1336        id->active_pages[area] = 0;
1337        for(i = 0; i < id->pages_per_area; i++) {
1338                    memset(id->areas[area][i],0,PAGE_SIZE);
1339        }
1340        }
1341        spin_unlock_irqrestore(&id->lock,flags);
1342}
1343
1344/*
1345 * view function: flushes debug areas
1346 */
1347
1348static int
1349debug_input_flush_fn(debug_info_t * id, struct debug_view *view,
1350            struct file *file, const char __user *user_buf,
1351            size_t user_len, loff_t * offset)
1352{
1353        char input_buf[1];
1354        int rc = user_len;
1355
1356    if (user_len > 0x10000)
1357                user_len = 0x10000;
1358        if (*offset != 0){
1359        rc = -EPIPE;
1360                goto out;
1361    }
1362        if (copy_from_user(input_buf, user_buf, 1)){
1363                rc = -EFAULT;
1364                goto out;
1365        }
1366        if(input_buf[0] == '-') {
1367                debug_flush(id, DEBUG_FLUSH_ALL);
1368                goto out;
1369        }
1370        if (isdigit(input_buf[0])) {
1371                int area = ((int) input_buf[0] - (int) '0');
1372                debug_flush(id, area);
1373                goto out;
1374        }
1375
1376    pr_info("Flushing debug data failed because %c is not a valid "
1377         "area\n", input_buf[0]);
1378
1379out:
1380        *offset += user_len;
1381        return rc; /* number of input characters */
1382}
1383
1384/*
1385 * prints debug header in raw format
1386 */
1387
1388static int
1389debug_raw_header_fn(debug_info_t * id, struct debug_view *view,
1390            int area, debug_entry_t * entry, char *out_buf)
1391{
1392        int rc;
1393
1394    rc = sizeof(debug_entry_t);
1395    memcpy(out_buf,entry,sizeof(debug_entry_t));
1396        return rc;
1397}
1398
1399/*
1400 * prints debug data in raw format
1401 */
1402
1403static int
1404debug_raw_format_fn(debug_info_t * id, struct debug_view *view,
1405                   char *out_buf, const char *in_buf)
1406{
1407    int rc;
1408
1409    rc = id->buf_size;
1410    memcpy(out_buf, in_buf, id->buf_size);
1411    return rc;
1412}
1413
1414/*
1415 * prints debug data in hex/ascii format
1416 */
1417
1418static int
1419debug_hex_ascii_format_fn(debug_info_t * id, struct debug_view *view,
1420                  char *out_buf, const char *in_buf)
1421{
1422    int i, rc = 0;
1423
1424    for (i = 0; i < id->buf_size; i++) {
1425                rc += sprintf(out_buf + rc, "%02x ",
1426                              ((unsigned char *) in_buf)[i]);
1427        }
1428    rc += sprintf(out_buf + rc, "| ");
1429    for (i = 0; i < id->buf_size; i++) {
1430        unsigned char c = in_buf[i];
1431        if (!isprint(c))
1432            rc += sprintf(out_buf + rc, ".");
1433        else
1434            rc += sprintf(out_buf + rc, "%c", c);
1435    }
1436    rc += sprintf(out_buf + rc, "\n");
1437    return rc;
1438}
1439
1440/*
1441 * prints header for debug entry
1442 */
1443
1444int
1445debug_dflt_header_fn(debug_info_t * id, struct debug_view *view,
1446             int area, debug_entry_t * entry, char *out_buf)
1447{
1448    struct timespec time_spec;
1449    char *except_str;
1450    unsigned long caller;
1451    int rc = 0;
1452    unsigned int level;
1453
1454    level = entry->id.fields.level;
1455    stck_to_timespec(entry->id.stck, &time_spec);
1456
1457    if (entry->id.fields.exception)
1458        except_str = "*";
1459    else
1460        except_str = "-";
1461    caller = ((unsigned long) entry->caller) & PSW_ADDR_INSN;
1462    rc += sprintf(out_buf, "%02i %011lu:%06lu %1u %1s %02i %p ",
1463              area, time_spec.tv_sec, time_spec.tv_nsec / 1000, level,
1464              except_str, entry->id.fields.cpuid, (void *) caller);
1465    return rc;
1466}
1467
1468/*
1469 * prints debug data sprintf-formated:
1470 * debug_sprinf_event/exception calls must be used together with this view
1471 */
1472
1473#define DEBUG_SPRINTF_MAX_ARGS 10
1474
1475static int
1476debug_sprintf_format_fn(debug_info_t * id, struct debug_view *view,
1477                        char *out_buf, debug_sprintf_entry_t *curr_event)
1478{
1479    int num_longs, num_used_args = 0,i, rc = 0;
1480    int index[DEBUG_SPRINTF_MAX_ARGS];
1481
1482    /* count of longs fit into one entry */
1483    num_longs = id->buf_size / sizeof(long);
1484
1485    if(num_longs < 1)
1486        goto out; /* bufsize of entry too small */
1487    if(num_longs == 1) {
1488        /* no args, we use only the string */
1489        strcpy(out_buf, curr_event->string);
1490        rc = strlen(curr_event->string);
1491        goto out;
1492    }
1493
1494    /* number of arguments used for sprintf (without the format string) */
1495    num_used_args = min(DEBUG_SPRINTF_MAX_ARGS, (num_longs - 1));
1496
1497    memset(index,0, DEBUG_SPRINTF_MAX_ARGS * sizeof(int));
1498
1499    for(i = 0; i < num_used_args; i++)
1500        index[i] = i;
1501
1502    rc = sprintf(out_buf, curr_event->string, curr_event->args[index[0]],
1503        curr_event->args[index[1]], curr_event->args[index[2]],
1504        curr_event->args[index[3]], curr_event->args[index[4]],
1505        curr_event->args[index[5]], curr_event->args[index[6]],
1506        curr_event->args[index[7]], curr_event->args[index[8]],
1507        curr_event->args[index[9]]);
1508
1509out:
1510
1511    return rc;
1512}
1513
1514/*
1515 * clean up module
1516 */
1517static void __exit debug_exit(void)
1518{
1519    debugfs_remove(debug_debugfs_root_entry);
1520    unregister_sysctl_table(s390dbf_sysctl_header);
1521    return;
1522}
1523
1524/*
1525 * module definitions
1526 */
1527postcore_initcall(debug_init);
1528module_exit(debug_exit);
1529MODULE_LICENSE("GPL");
1530
1531EXPORT_SYMBOL(debug_register);
1532EXPORT_SYMBOL(debug_unregister);
1533EXPORT_SYMBOL(debug_set_level);
1534EXPORT_SYMBOL(debug_stop_all);
1535EXPORT_SYMBOL(debug_register_view);
1536EXPORT_SYMBOL(debug_unregister_view);
1537EXPORT_SYMBOL(debug_event_common);
1538EXPORT_SYMBOL(debug_exception_common);
1539EXPORT_SYMBOL(debug_hex_ascii_view);
1540EXPORT_SYMBOL(debug_raw_view);
1541EXPORT_SYMBOL(debug_dflt_header_fn);
1542EXPORT_SYMBOL(debug_sprintf_view);
1543EXPORT_SYMBOL(debug_sprintf_exception);
1544EXPORT_SYMBOL(debug_sprintf_event);
1545

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