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2024-12-19 9370bb92b2d16684ee45cf24e879c93c509162da 
 kernel/arch/s390/kernel/debug.c
....@@ -2,7 +2,7 @@
22 /*
33  *   S/390 debug facility
44  *
5
- *    Copyright IBM Corp. 1999, 2012
5
+ *    Copyright IBM Corp. 1999, 2020
66  *
77  *    Author(s): Michael Holzheu (holzheu@de.ibm.com),
88  *		 Holger Smolinski (Holger.Smolinski@de.ibm.com)
....@@ -24,6 +24,7 @@
2424 #include <linux/export.h>
2525 #include <linux/init.h>
2626 #include <linux/fs.h>
27
+#include <linux/minmax.h>
2728 #include <linux/debugfs.h>
2829 
2930 #include <asm/debug.h>
....@@ -90,26 +91,12 @@
9091 				size_t user_buf_size, loff_t *offset);
9192 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
9293 				     char *out_buf, const char *in_buf);
93
-static int debug_raw_format_fn(debug_info_t *id,
94
-			       struct debug_view *view, char *out_buf,
95
-			       const char *in_buf);
96
-static int debug_raw_header_fn(debug_info_t *id, struct debug_view *view,
97
-			       int area, debug_entry_t *entry, char *out_buf);
98
-
9994 static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
10095 				   char *out_buf, debug_sprintf_entry_t *curr_event);
96
+static void debug_areas_swap(debug_info_t *a, debug_info_t *b);
97
+static void debug_events_append(debug_info_t *dest, debug_info_t *src);
10198 
10299 /* globals */
103
-
104
-struct debug_view debug_raw_view = {
105
-	"raw",
106
-	NULL,
107
-	&debug_raw_header_fn,
108
-	&debug_raw_format_fn,
109
-	NULL,
110
-	NULL
111
-};
112
-EXPORT_SYMBOL(debug_raw_view);
113100 
114101 struct debug_view debug_hex_ascii_view = {
115102 	"hex_ascii",
....@@ -327,24 +314,6 @@
327314 		goto out;
328315 
329316 	rc->mode = mode & ~S_IFMT;
330
-
331
-	/* create root directory */
332
-	rc->debugfs_root_entry = debugfs_create_dir(rc->name,
333
-						    debug_debugfs_root_entry);
334
-
335
-	/* append new element to linked list */
336
-	if (!debug_area_first) {
337
-		/* first element in list */
338
-		debug_area_first = rc;
339
-		rc->prev = NULL;
340
-	} else {
341
-		/* append element to end of list */
342
-		debug_area_last->next = rc;
343
-		rc->prev = debug_area_last;
344
-	}
345
-	debug_area_last = rc;
346
-	rc->next = NULL;
347
-
348317 	refcount_set(&rc->ref_count, 1);
349318 out:
350319 	return rc;
....@@ -404,27 +373,10 @@
404373  */
405374 static void debug_info_put(debug_info_t *db_info)
406375 {
407
-	int i;
408
-
409376 	if (!db_info)
410377 		return;
411
-	if (refcount_dec_and_test(&db_info->ref_count)) {
412
-		for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
413
-			if (!db_info->views[i])
414
-				continue;
415
-			debugfs_remove(db_info->debugfs_entries[i]);
416
-		}
417
-		debugfs_remove(db_info->debugfs_root_entry);
418
-		if (db_info == debug_area_first)
419
-			debug_area_first = db_info->next;
420
-		if (db_info == debug_area_last)
421
-			debug_area_last = db_info->prev;
422
-		if (db_info->prev)
423
-			db_info->prev->next = db_info->next;
424
-		if (db_info->next)
425
-			db_info->next->prev = db_info->prev;
378
+	if (refcount_dec_and_test(&db_info->ref_count))
426379 		debug_info_free(db_info);
427
-	}
428380 }
429381 
430382 /*
....@@ -449,7 +401,7 @@
449401 	act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
450402 				       [p_info->act_page] + p_info->act_entry);
451403 
452
-	if (act_entry->id.stck == 0LL)
404
+	if (act_entry->clock == 0LL)
453405 		goto out; /* empty entry */
454406 	if (view->header_proc)
455407 		len += view->header_proc(id_snap, view, p_info->act_area,
....@@ -648,11 +600,48 @@
648600 	return 0; /* success */
649601 }
650602 
651
-/*
652
- * debug_register_mode:
653
- * - Creates and initializes debug area for the caller
654
- *   The mode parameter allows to specify access rights for the s390dbf files
655
- * - Returns handle for debug area
603
+/* Create debugfs entries and add to internal list. */
604
+static 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.
656645  */
657646 debug_info_t *debug_register_mode(const char *name, int pages_per_area,
658647 				  int nr_areas, int buf_size, umode_t mode,
....@@ -665,27 +654,35 @@
665654 	if ((uid != 0) || (gid != 0))
666655 		pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
667656 	BUG_ON(!initialized);
668
-	mutex_lock(&debug_mutex);
669657 
670658 	/* create new debug_info */
671659 	rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
672
-	if (!rc)
673
-		goto out;
674
-	debug_register_view(rc, &debug_level_view);
675
-	debug_register_view(rc, &debug_flush_view);
676
-	debug_register_view(rc, &debug_pages_view);
677
-out:
678
-	if (!rc)
660
+	if (rc) {
661
+		mutex_lock(&debug_mutex);
662
+		_debug_register(rc);
663
+		mutex_unlock(&debug_mutex);
664
+	} else {
679665 		pr_err("Registering debug feature %s failed\n", name);
680
-	mutex_unlock(&debug_mutex);
666
+	}
681667 	return rc;
682668 }
683669 EXPORT_SYMBOL(debug_register_mode);
684670 
685
-/*
686
- * debug_register:
687
- * - creates and initializes debug area for the caller
688
- * - returns handle for debug area
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.
689686  */
690687 debug_info_t *debug_register(const char *name, int pages_per_area,
691688 			     int nr_areas, int buf_size)
....@@ -695,17 +692,44 @@
695692 }
696693 EXPORT_SYMBOL(debug_register);
697694 
698
-/*
699
- * debug_unregister:
700
- * - give back debug area
695
+/* Remove debugfs entries and remove from internal list. */
696
+static void _debug_unregister(debug_info_t *id)
697
+{
698
+	int i;
699
+
700
+	for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
701
+		if (!id->views[i])
702
+			continue;
703
+		debugfs_remove(id->debugfs_entries[i]);
704
+	}
705
+	debugfs_remove(id->debugfs_root_entry);
706
+	if (id == debug_area_first)
707
+		debug_area_first = id->next;
708
+	if (id == debug_area_last)
709
+		debug_area_last = id->prev;
710
+	if (id->prev)
711
+		id->prev->next = id->next;
712
+	if (id->next)
713
+		id->next->prev = id->prev;
714
+}
715
+
716
+/**
717
+ * debug_unregister() - give back debug area.
718
+ *
719
+ * @id:		handle for debug log
720
+ *
721
+ * Return:
722
+ *    none
701723  */
702724 void debug_unregister(debug_info_t *id)
703725 {
704726 	if (!id)
705727 		return;
706728 	mutex_lock(&debug_mutex);
707
-	debug_info_put(id);
729
+	_debug_unregister(id);
708730 	mutex_unlock(&debug_mutex);
731
+
732
+	debug_info_put(id);
709733 }
710734 EXPORT_SYMBOL(debug_unregister);
711735 
....@@ -715,40 +739,38 @@
715739  */
716740 static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
717741 {
718
-	debug_entry_t ***new_areas;
742
+	debug_info_t *new_id;
719743 	unsigned long flags;
720
-	int rc = 0;
721744 
722745 	if (!id || (nr_areas <= 0) || (pages_per_area < 0))
723746 		return -EINVAL;
724
-	if (pages_per_area > 0) {
725
-		new_areas = debug_areas_alloc(pages_per_area, nr_areas);
726
-		if (!new_areas) {
727
-			pr_info("Allocating memory for %i pages failed\n",
728
-				pages_per_area);
729
-			rc = -ENOMEM;
730
-			goto out;
731
-		}
732
-	} else {
733
-		new_areas = NULL;
747
+
748
+	new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
749
+				  id->level, ALL_AREAS);
750
+	if (!new_id) {
751
+		pr_info("Allocating memory for %i pages failed\n",
752
+			pages_per_area);
753
+		return -ENOMEM;
734754 	}
755
+
735756 	spin_lock_irqsave(&id->lock, flags);
736
-	debug_areas_free(id);
737
-	id->areas = new_areas;
738
-	id->nr_areas = nr_areas;
739
-	id->pages_per_area = pages_per_area;
740
-	id->active_area = 0;
741
-	memset(id->active_entries, 0, sizeof(int)*id->nr_areas);
742
-	memset(id->active_pages, 0, sizeof(int)*id->nr_areas);
757
+	debug_events_append(new_id, id);
758
+	debug_areas_swap(new_id, id);
759
+	debug_info_free(new_id);
743760 	spin_unlock_irqrestore(&id->lock, flags);
744761 	pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
745
-out:
746
-	return rc;
762
+
763
+	return 0;
747764 }
748765 
749
-/*
750
- * debug_set_level:
751
- * - set actual debug level
766
+/**
767
+ * debug_set_level() - Sets new actual debug level if new_level is valid.
768
+ *
769
+ * @id:		handle for debug log
770
+ * @new_level:	new debug level
771
+ *
772
+ * Return:
773
+ *    none
752774  */
753775 void debug_set_level(debug_info_t *id, int new_level)
754776 {
....@@ -805,6 +827,42 @@
805827 				  id->active_entries[id->active_area]);
806828 }
807829 
830
+/* Swap debug areas of a and b. */
831
+static void debug_areas_swap(debug_info_t *a, debug_info_t *b)
832
+{
833
+	swap(a->nr_areas, b->nr_areas);
834
+	swap(a->pages_per_area, b->pages_per_area);
835
+	swap(a->areas, b->areas);
836
+	swap(a->active_area, b->active_area);
837
+	swap(a->active_pages, b->active_pages);
838
+	swap(a->active_entries, b->active_entries);
839
+}
840
+
841
+/* Append all debug events in active area from source to destination log. */
842
+static void debug_events_append(debug_info_t *dest, debug_info_t *src)
843
+{
844
+	debug_entry_t *from, *to, *last;
845
+
846
+	if (!src->areas || !dest->areas)
847
+		return;
848
+
849
+	/* Loop over all entries in src, starting with oldest. */
850
+	from = get_active_entry(src);
851
+	last = from;
852
+	do {
853
+		if (from->clock != 0LL) {
854
+			to = get_active_entry(dest);
855
+			memset(to, 0, dest->entry_size);
856
+			memcpy(to, from, min(src->entry_size,
857
+					     dest->entry_size));
858
+			proceed_active_entry(dest);
859
+		}
860
+
861
+		proceed_active_entry(src);
862
+		from = get_active_entry(src);
863
+	} while (from != last);
864
+}
865
+
808866 /*
809867  * debug_finish_entry:
810868  * - set timestamp, caller address, cpu number etc.
....@@ -813,12 +871,17 @@
813871 static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
814872 				      int level, int exception)
815873 {
816
-	active->id.stck = get_tod_clock_fast() -
817
-		*(unsigned long long *) &tod_clock_base[1];
818
-	active->id.fields.cpuid = smp_processor_id();
874
+	unsigned char clk[STORE_CLOCK_EXT_SIZE];
875
+	unsigned long timestamp;
876
+
877
+	get_tod_clock_ext(clk);
878
+	timestamp = *(unsigned long *) &clk[0] >> 4;
879
+	timestamp -= TOD_UNIX_EPOCH >> 12;
880
+	active->clock = timestamp;
881
+	active->cpu = smp_processor_id();
819882 	active->caller = __builtin_return_address(0);
820
-	active->id.fields.exception = exception;
821
-	active->id.fields.level = level;
883
+	active->exception = exception;
884
+	active->level = level;
822885 	proceed_active_entry(id);
823886 	if (exception)
824887 		proceed_active_area(id);
....@@ -836,7 +899,7 @@
836899  * if debug_active is already off
837900  */
838901 static int s390dbf_procactive(struct ctl_table *table, int write,
839
-			      void __user *buffer, size_t *lenp, loff_t *ppos)
902
+			      void *buffer, size_t *lenp, loff_t *ppos)
840903 {
841904 	if (!write || debug_stoppable || !debug_active)
842905 		return proc_dointvec(table, write, buffer, lenp, ppos);
....@@ -874,6 +937,14 @@
874937 
875938 static struct ctl_table_header *s390dbf_sysctl_header;
876939 
940
+/**
941
+ * debug_stop_all() - stops the debug feature if stopping is allowed.
942
+ *
943
+ * Return:
944
+ * -   none
945
+ *
946
+ * Currently used in case of a kernel oops.
947
+ */
877948 void debug_stop_all(void)
878949 {
879950 	if (debug_stoppable)
....@@ -881,6 +952,17 @@
881952 }
882953 EXPORT_SYMBOL(debug_stop_all);
883954 
955
+/**
956
+ * debug_set_critical() - event/exception functions try lock instead of spin.
957
+ *
958
+ * Return:
959
+ * -   none
960
+ *
961
+ * Currently used in case of stopping all CPUs but the current one.
962
+ * Once in this state, functions to write a debug entry for an
963
+ * event or exception no longer spin on the debug area lock,
964
+ * but only try to get it and fail if they do not get the lock.
965
+ */
884966 void debug_set_critical(void)
885967 {
886968 	debug_critical = 1;
....@@ -1037,8 +1119,16 @@
10371119 }
10381120 EXPORT_SYMBOL(__debug_sprintf_exception);
10391121 
1040
-/*
1041
- * debug_register_view:
1122
+/**
1123
+ * debug_register_view() - registers new debug view and creates debugfs
1124
+ *			   dir entry
1125
+ *
1126
+ * @id:		handle for debug log
1127
+ * @view:	pointer to debug view struct
1128
+ *
1129
+ * Return:
1130
+ * -   0  : ok
1131
+ * -   < 0: Error
10421132  */
10431133 int debug_register_view(debug_info_t *id, struct debug_view *view)
10441134 {
....@@ -1057,12 +1147,6 @@
10571147 		mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
10581148 	pde = debugfs_create_file(view->name, mode, id->debugfs_root_entry,
10591149 				  id, &debug_file_ops);
1060
-	if (!pde) {
1061
-		pr_err("Registering view %s/%s failed due to out of "
1062
-		       "memory\n", id->name, view->name);
1063
-		rc = -1;
1064
-		goto out;
1065
-	}
10661150 	spin_lock_irqsave(&id->lock, flags);
10671151 	for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
10681152 		if (!id->views[i])
....@@ -1084,8 +1168,16 @@
10841168 }
10851169 EXPORT_SYMBOL(debug_register_view);
10861170 
1087
-/*
1088
- * debug_unregister_view:
1171
+/**
1172
+ * debug_unregister_view() - unregisters debug view and removes debugfs
1173
+ *			     dir entry
1174
+ *
1175
+ * @id:		handle for debug log
1176
+ * @view:	pointer to debug view struct
1177
+ *
1178
+ * Return:
1179
+ * -   0  : ok
1180
+ * -   < 0: Error
10891181  */
10901182 int debug_unregister_view(debug_info_t *id, struct debug_view *view)
10911183 {
....@@ -1325,32 +1417,6 @@
13251417 }
13261418 
13271419 /*
1328
- * prints debug header in raw format
1329
- */
1330
-static int debug_raw_header_fn(debug_info_t *id, struct debug_view *view,
1331
-			       int area, debug_entry_t *entry, char *out_buf)
1332
-{
1333
-	int rc;
1334
-
1335
-	rc = sizeof(debug_entry_t);
1336
-	memcpy(out_buf, entry, sizeof(debug_entry_t));
1337
-	return rc;
1338
-}
1339
-
1340
-/*
1341
- * prints debug data in raw format
1342
- */
1343
-static int debug_raw_format_fn(debug_info_t *id, struct debug_view *view,
1344
-			       char *out_buf, const char *in_buf)
1345
-{
1346
-	int rc;
1347
-
1348
-	rc = id->buf_size;
1349
-	memcpy(out_buf, in_buf, id->buf_size);
1350
-	return rc;
1351
-}
1352
-
1353
-/*
13541420  * prints debug data in hex/ascii format
13551421  */
13561422 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
....@@ -1379,25 +1445,24 @@
13791445 int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
13801446 			 int area, debug_entry_t *entry, char *out_buf)
13811447 {
1382
-	unsigned long base, sec, usec;
1448
+	unsigned long sec, usec;
13831449 	unsigned long caller;
13841450 	unsigned int level;
13851451 	char *except_str;
13861452 	int rc = 0;
13871453 
1388
-	level = entry->id.fields.level;
1389
-	base = (*(unsigned long *) &tod_clock_base[0]) >> 4;
1390
-	sec = (entry->id.stck >> 12) + base - (TOD_UNIX_EPOCH >> 12);
1454
+	level = entry->level;
1455
+	sec = entry->clock;
13911456 	usec = do_div(sec, USEC_PER_SEC);
13921457 
1393
-	if (entry->id.fields.exception)
1458
+	if (entry->exception)
13941459 		except_str = "*";
13951460 	else
13961461 		except_str = "-";
13971462 	caller = (unsigned long) entry->caller;
1398
-	rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %02i %pK  ",
1463
+	rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %04u %pK  ",
13991464 		      area, sec, usec, level, except_str,
1400
-		      entry->id.fields.cpuid, (void *)caller);
1465
+		      entry->cpu, (void *)caller);
14011466 	return rc;
14021467 }
14031468 EXPORT_SYMBOL(debug_dflt_header_fn);