1 files changed, 195 insertions, 133 deletions

diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c
index 6d321f5f101d..d7a82066a638 100644
--- a/arch/s390/kernel/debug.c
+++ b/arch/s390/kernel/debug.c
@@ -2,7 +2,7 @@
 /*
  *   S/390 debug facility
  *
- *    Copyright IBM Corp. 1999, 2012
+ *    Copyright IBM Corp. 1999, 2020
  *
  *    Author(s): Michael Holzheu (holzheu@de.ibm.com),
  *		 Holger Smolinski (Holger.Smolinski@de.ibm.com)
@@ -24,6 +24,7 @@
 #include <linux/export.h>
 #include <linux/init.h>
 #include <linux/fs.h>
+#include <linux/minmax.h>
 #include <linux/debugfs.h>
 
 #include <asm/debug.h>
@@ -90,27 +91,13 @@ static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,
 				size_t user_buf_size, loff_t *offset);
 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
 				     char *out_buf, const char *in_buf);
-static int debug_raw_format_fn(debug_info_t *id,
-			       struct debug_view *view, char *out_buf,
-			       const char *in_buf);
-static int debug_raw_header_fn(debug_info_t *id, struct debug_view *view,
-			       int area, debug_entry_t *entry, char *out_buf);
-
 static int debug_sprintf_format_fn(debug_info_t *id, struct debug_view *view,
 				   char *out_buf, debug_sprintf_entry_t *curr_event);
+static void debug_areas_swap(debug_info_t *a, debug_info_t *b);
+static void debug_events_append(debug_info_t *dest, debug_info_t *src);
 
 /* globals */
 
-struct debug_view debug_raw_view = {
-	"raw",
-	NULL,
-	&debug_raw_header_fn,
-	&debug_raw_format_fn,
-	NULL,
-	NULL
-};
-EXPORT_SYMBOL(debug_raw_view);
-
 struct debug_view debug_hex_ascii_view = {
 	"hex_ascii",
 	NULL,
@@ -198,9 +185,10 @@ static debug_entry_t ***debug_areas_alloc(int pages_per_area, int nr_areas)
 	if (!areas)
 		goto fail_malloc_areas;
 	for (i = 0; i < nr_areas; i++) {
+		/* GFP_NOWARN to avoid user triggerable WARN, we handle fails */
 		areas[i] = kmalloc_array(pages_per_area,
 					 sizeof(debug_entry_t *),
-					 GFP_KERNEL);
+					 GFP_KERNEL | __GFP_NOWARN);
 		if (!areas[i])
 			goto fail_malloc_areas2;
 		for (j = 0; j < pages_per_area; j++) {
@@ -262,7 +250,7 @@ static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,
 	rc->level	   = level;
 	rc->buf_size	   = buf_size;
 	rc->entry_size	   = sizeof(debug_entry_t) + buf_size;
-	strlcpy(rc->name, name, sizeof(rc->name));
+	strscpy(rc->name, name, sizeof(rc->name));
 	memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
 	memset(rc->debugfs_entries, 0, DEBUG_MAX_VIEWS * sizeof(struct dentry *));
 	refcount_set(&(rc->ref_count), 0);
@@ -326,24 +314,6 @@ static debug_info_t *debug_info_create(const char *name, int pages_per_area,
 		goto out;
 
 	rc->mode = mode & ~S_IFMT;
-
-	/* create root directory */
-	rc->debugfs_root_entry = debugfs_create_dir(rc->name,
-						    debug_debugfs_root_entry);
-
-	/* append new element to linked list */
-	if (!debug_area_first) {
-		/* first element in list */
-		debug_area_first = rc;
-		rc->prev = NULL;
-	} else {
-		/* append element to end of list */
-		debug_area_last->next = rc;
-		rc->prev = debug_area_last;
-	}
-	debug_area_last = rc;
-	rc->next = NULL;
-
 	refcount_set(&rc->ref_count, 1);
 out:
 	return rc;
@@ -403,27 +373,10 @@ static void debug_info_get(debug_info_t *db_info)
  */
 static void debug_info_put(debug_info_t *db_info)
 {
-	int i;
-
 	if (!db_info)
 		return;
-	if (refcount_dec_and_test(&db_info->ref_count)) {
-		for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
-			if (!db_info->views[i])
-				continue;
-			debugfs_remove(db_info->debugfs_entries[i]);
-		}
-		debugfs_remove(db_info->debugfs_root_entry);
-		if (db_info == debug_area_first)
-			debug_area_first = db_info->next;
-		if (db_info == debug_area_last)
-			debug_area_last = db_info->prev;
-		if (db_info->prev)
-			db_info->prev->next = db_info->next;
-		if (db_info->next)
-			db_info->next->prev = db_info->prev;
+	if (refcount_dec_and_test(&db_info->ref_count))
 		debug_info_free(db_info);
-	}
 }
 
 /*
@@ -448,7 +401,7 @@ static int debug_format_entry(file_private_info_t *p_info)
 	act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]
 				       [p_info->act_page] + p_info->act_entry);
 
-	if (act_entry->id.stck == 0LL)
+	if (act_entry->clock == 0LL)
 		goto out; /* empty entry */
 	if (view->header_proc)
 		len += view->header_proc(id_snap, view, p_info->act_area,
@@ -647,6 +600,31 @@ static int debug_close(struct inode *inode, struct file *file)
 	return 0; /* success */
 }
 
+/* Create debugfs entries and add to internal list. */
+static void _debug_register(debug_info_t *id)
+{
+	/* create root directory */
+	id->debugfs_root_entry = debugfs_create_dir(id->name,
+						    debug_debugfs_root_entry);
+
+	/* append new element to linked list */
+	if (!debug_area_first) {
+		/* first element in list */
+		debug_area_first = id;
+		id->prev = NULL;
+	} else {
+		/* append element to end of list */
+		debug_area_last->next = id;
+		id->prev = debug_area_last;
+	}
+	debug_area_last = id;
+	id->next = NULL;
+
+	debug_register_view(id, &debug_level_view);
+	debug_register_view(id, &debug_flush_view);
+	debug_register_view(id, &debug_pages_view);
+}
+
 /**
  * debug_register_mode() - creates and initializes debug area.
  *
@@ -676,19 +654,16 @@ debug_info_t *debug_register_mode(const char *name, int pages_per_area,
 	if ((uid != 0) || (gid != 0))
 		pr_warn("Root becomes the owner of all s390dbf files in sysfs\n");
 	BUG_ON(!initialized);
-	mutex_lock(&debug_mutex);
 
 	/* create new debug_info */
 	rc = debug_info_create(name, pages_per_area, nr_areas, buf_size, mode);
-	if (!rc)
-		goto out;
-	debug_register_view(rc, &debug_level_view);
-	debug_register_view(rc, &debug_flush_view);
-	debug_register_view(rc, &debug_pages_view);
-out:
-	if (!rc)
+	if (rc) {
+		mutex_lock(&debug_mutex);
+		_debug_register(rc);
+		mutex_unlock(&debug_mutex);
+	} else {
 		pr_err("Registering debug feature %s failed\n", name);
-	mutex_unlock(&debug_mutex);
+	}
 	return rc;
 }
 EXPORT_SYMBOL(debug_register_mode);
@@ -718,6 +693,82 @@ debug_info_t *debug_register(const char *name, int pages_per_area,
 EXPORT_SYMBOL(debug_register);
 
 /**
+ * debug_register_static() - registers a static debug area
+ *
+ * @id: Handle for static debug area
+ * @pages_per_area: Number of pages per area
+ * @nr_areas: Number of debug areas
+ *
+ * Register debug_info_t defined using DEFINE_STATIC_DEBUG_INFO.
+ *
+ * Note: This function is called automatically via an initcall generated by
+ *	 DEFINE_STATIC_DEBUG_INFO.
+ */
+void debug_register_static(debug_info_t *id, int pages_per_area, int nr_areas)
+{
+	unsigned long flags;
+	debug_info_t *copy;
+
+	if (!initialized) {
+		pr_err("Tried to register debug feature %s too early\n",
+		       id->name);
+		return;
+	}
+
+	copy = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
+				id->level, ALL_AREAS);
+	if (!copy) {
+		pr_err("Registering debug feature %s failed\n", id->name);
+
+		/* Clear pointers to prevent tracing into released initdata. */
+		spin_lock_irqsave(&id->lock, flags);
+		id->areas = NULL;
+		id->active_pages = NULL;
+		id->active_entries = NULL;
+		spin_unlock_irqrestore(&id->lock, flags);
+
+		return;
+	}
+
+	/* Replace static trace area with dynamic copy. */
+	spin_lock_irqsave(&id->lock, flags);
+	debug_events_append(copy, id);
+	debug_areas_swap(id, copy);
+	spin_unlock_irqrestore(&id->lock, flags);
+
+	/* Clear pointers to initdata and discard copy. */
+	copy->areas = NULL;
+	copy->active_pages = NULL;
+	copy->active_entries = NULL;
+	debug_info_free(copy);
+
+	mutex_lock(&debug_mutex);
+	_debug_register(id);
+	mutex_unlock(&debug_mutex);
+}
+
+/* Remove debugfs entries and remove from internal list. */
+static void _debug_unregister(debug_info_t *id)
+{
+	int i;
+
+	for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
+		if (!id->views[i])
+			continue;
+		debugfs_remove(id->debugfs_entries[i]);
+	}
+	debugfs_remove(id->debugfs_root_entry);
+	if (id == debug_area_first)
+		debug_area_first = id->next;
+	if (id == debug_area_last)
+		debug_area_last = id->prev;
+	if (id->prev)
+		id->prev->next = id->next;
+	if (id->next)
+		id->next->prev = id->prev;
+}
+
+/**
  * debug_unregister() - give back debug area.
  *
  * @id:		handle for debug log
@@ -730,8 +781,10 @@ void debug_unregister(debug_info_t *id)
 	if (!id)
 		return;
 	mutex_lock(&debug_mutex);
-	debug_info_put(id);
+	_debug_unregister(id);
 	mutex_unlock(&debug_mutex);
+
+	debug_info_put(id);
 }
 EXPORT_SYMBOL(debug_unregister);
 
@@ -741,35 +794,28 @@ EXPORT_SYMBOL(debug_unregister);
  */
 static int debug_set_size(debug_info_t *id, int nr_areas, int pages_per_area)
 {
-	debug_entry_t ***new_areas;
+	debug_info_t *new_id;
 	unsigned long flags;
-	int rc = 0;
 
 	if (!id || (nr_areas <= 0) || (pages_per_area < 0))
 		return -EINVAL;
-	if (pages_per_area > 0) {
-		new_areas = debug_areas_alloc(pages_per_area, nr_areas);
-		if (!new_areas) {
-			pr_info("Allocating memory for %i pages failed\n",
-				pages_per_area);
-			rc = -ENOMEM;
-			goto out;
-		}
-	} else {
-		new_areas = NULL;
+
+	new_id = debug_info_alloc("", pages_per_area, nr_areas, id->buf_size,
+				  id->level, ALL_AREAS);
+	if (!new_id) {
+		pr_info("Allocating memory for %i pages failed\n",
+			pages_per_area);
+		return -ENOMEM;
 	}
+
 	spin_lock_irqsave(&id->lock, flags);
-	debug_areas_free(id);
-	id->areas = new_areas;
-	id->nr_areas = nr_areas;
-	id->pages_per_area = pages_per_area;
-	id->active_area = 0;
-	memset(id->active_entries, 0, sizeof(int)*id->nr_areas);
-	memset(id->active_pages, 0, sizeof(int)*id->nr_areas);
+	debug_events_append(new_id, id);
+	debug_areas_swap(new_id, id);
+	debug_info_free(new_id);
 	spin_unlock_irqrestore(&id->lock, flags);
 	pr_info("%s: set new size (%i pages)\n", id->name, pages_per_area);
-out:
-	return rc;
+
+	return 0;
 }
 
 /**
@@ -787,16 +833,17 @@ void debug_set_level(debug_info_t *id, int new_level)
 
 	if (!id)
 		return;
-	spin_lock_irqsave(&id->lock, flags);
+
 	if (new_level == DEBUG_OFF_LEVEL) {
-		id->level = DEBUG_OFF_LEVEL;
 		pr_info("%s: switched off\n", id->name);
 	} else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
 		pr_info("%s: level %i is out of range (%i - %i)\n",
 			id->name, new_level, 0, DEBUG_MAX_LEVEL);
-	} else {
-		id->level = new_level;
+		return;
 	}
+
+	spin_lock_irqsave(&id->lock, flags);
+	id->level = new_level;
 	spin_unlock_irqrestore(&id->lock, flags);
 }
 EXPORT_SYMBOL(debug_set_level);
@@ -836,6 +883,42 @@ static inline debug_entry_t *get_active_entry(debug_info_t *id)
 				  id->active_entries[id->active_area]);
 }
 
+/* Swap debug areas of a and b. */
+static void debug_areas_swap(debug_info_t *a, debug_info_t *b)
+{
+	swap(a->nr_areas, b->nr_areas);
+	swap(a->pages_per_area, b->pages_per_area);
+	swap(a->areas, b->areas);
+	swap(a->active_area, b->active_area);
+	swap(a->active_pages, b->active_pages);
+	swap(a->active_entries, b->active_entries);
+}
+
+/* Append all debug events in active area from source to destination log. */
+static void debug_events_append(debug_info_t *dest, debug_info_t *src)
+{
+	debug_entry_t *from, *to, *last;
+
+	if (!src->areas || !dest->areas)
+		return;
+
+	/* Loop over all entries in src, starting with oldest. */
+	from = get_active_entry(src);
+	last = from;
+	do {
+		if (from->clock != 0LL) {
+			to = get_active_entry(dest);
+			memset(to, 0, dest->entry_size);
+			memcpy(to, from, min(src->entry_size,
+					     dest->entry_size));
+			proceed_active_entry(dest);
+		}
+
+		proceed_active_entry(src);
+		from = get_active_entry(src);
+	} while (from != last);
+}
+
 /*
  * debug_finish_entry:
  * - set timestamp, caller address, cpu number etc.
@@ -844,12 +927,17 @@ static inline debug_entry_t *get_active_entry(debug_info_t *id)
 static inline void debug_finish_entry(debug_info_t *id, debug_entry_t *active,
 				      int level, int exception)
 {
-	active->id.stck = get_tod_clock_fast() -
-		*(unsigned long long *) &tod_clock_base[1];
-	active->id.fields.cpuid = smp_processor_id();
+	unsigned long timestamp;
+	union tod_clock clk;
+
+	store_tod_clock_ext(&clk);
+	timestamp = clk.us;
+	timestamp -= TOD_UNIX_EPOCH >> 12;
+	active->clock = timestamp;
+	active->cpu = smp_processor_id();
 	active->caller = __builtin_return_address(0);
-	active->id.fields.exception = exception;
-	active->id.fields.level = level;
+	active->exception = exception;
+	active->level = level;
 	proceed_active_entry(id);
 	if (exception)
 		proceed_active_area(id);
@@ -867,7 +955,7 @@ static int debug_active = 1;
  * if debug_active is already off
  */
 static int s390dbf_procactive(struct ctl_table *table, int write,
-			      void __user *buffer, size_t *lenp, loff_t *ppos)
+			      void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (!write || debug_stoppable || !debug_active)
 		return proc_dointvec(table, write, buffer, lenp, ppos);
@@ -1121,16 +1209,17 @@ int debug_register_view(debug_info_t *id, struct debug_view *view)
 			break;
 	}
 	if (i == DEBUG_MAX_VIEWS) {
-		pr_err("Registering view %s/%s would exceed the maximum "
-		       "number of views %i\n", id->name, view->name, i);
 		rc = -1;
 	} else {
 		id->views[i] = view;
 		id->debugfs_entries[i] = pde;
 	}
 	spin_unlock_irqrestore(&id->lock, flags);
-	if (rc)
+	if (rc) {
+		pr_err("Registering view %s/%s would exceed the maximum "
+		       "number of views %i\n", id->name, view->name, i);
 		debugfs_remove(pde);
+	}
 out:
 	return rc;
 }
@@ -1385,32 +1474,6 @@ out:
 }
 
 /*
- * prints debug header in raw format
- */
-static int debug_raw_header_fn(debug_info_t *id, struct debug_view *view,
-			       int area, debug_entry_t *entry, char *out_buf)
-{
-	int rc;
-
-	rc = sizeof(debug_entry_t);
-	memcpy(out_buf, entry, sizeof(debug_entry_t));
-	return rc;
-}
-
-/*
- * prints debug data in raw format
- */
-static int debug_raw_format_fn(debug_info_t *id, struct debug_view *view,
-			       char *out_buf, const char *in_buf)
-{
-	int rc;
-
-	rc = id->buf_size;
-	memcpy(out_buf, in_buf, id->buf_size);
-	return rc;
-}
-
-/*
  * prints debug data in hex/ascii format
  */
 static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
@@ -1439,25 +1502,24 @@ static int debug_hex_ascii_format_fn(debug_info_t *id, struct debug_view *view,
 int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view,
 			 int area, debug_entry_t *entry, char *out_buf)
 {
-	unsigned long base, sec, usec;
+	unsigned long sec, usec;
 	unsigned long caller;
 	unsigned int level;
 	char *except_str;
 	int rc = 0;
 
-	level = entry->id.fields.level;
-	base = (*(unsigned long *) &tod_clock_base[0]) >> 4;
-	sec = (entry->id.stck >> 12) + base - (TOD_UNIX_EPOCH >> 12);
+	level = entry->level;
+	sec = entry->clock;
 	usec = do_div(sec, USEC_PER_SEC);
 
-	if (entry->id.fields.exception)
+	if (entry->exception)
 		except_str = "*";
 	else
 		except_str = "-";
 	caller = (unsigned long) entry->caller;
-	rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %02i %pK  ",
+	rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %04u %px  ",
 		      area, sec, usec, level, except_str,
-		      entry->id.fields.cpuid, (void *)caller);
+		      entry->cpu, (void *)caller);
 	return rc;
 }
 EXPORT_SYMBOL(debug_dflt_header_fn);