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// SPDX-License-Identifier: GPL-2.0/* *   S/390 debug facility * *    Copyright IBM Corp. 1999, 2020 * *    Author(s): Michael Holzheu (holzheu@de.ibm.com), *		 Holger Smolinski (Holger.Smolinski@de.ibm.com) * *    Bugreports to: <Linux390@de.ibm.com> */ #define KMSG_COMPONENT "s390dbf"#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt #include <linux/stddef.h>#include <linux/kernel.h>#include <linux/errno.h>#include <linux/slab.h>#include <linux/ctype.h>#include <linux/string.h>#include <linux/sysctl.h>#include <linux/uaccess.h>#include <linux/export.h>#include <linux/init.h>#include <linux/fs.h>#include <linux/debugfs.h> #include <asm/debug.h> #define DEBUG_PROLOG_ENTRY -1 #define ALL_AREAS 0 /* copy all debug areas */#define NO_AREAS  1 /* copy no debug areas */ /* typedefs */ typedef struct file_private_info {	loff_t offset;			/* offset of last read in file */	int    act_area;		/* number of last formated area */	int    act_page;		/* act page in given area */	int    act_entry;		/* last formated entry (offset */					/* relative to beginning of last */					/* formated page) */	size_t act_entry_offset;	/* up to this offset we copied */					/* in last read the last formated */					/* entry to userland */	char   temp_buf[2048];		/* buffer for output */	debug_info_t *debug_info_org;	/* original debug information */	debug_info_t *debug_info_snap;	/* snapshot of debug information */	struct debug_view *view;	/* used view of debug info */} file_private_info_t; typedef struct {	char *string;	/*	 * This assumes that all args are converted into longs	 * on L/390 this is the case for all types of parameter	 * except of floats, and long long (32 bit)	 *	 */	long args[0];} debug_sprintf_entry_t; /* internal function prototyes */ static int debug_init(void);static ssize_t debug_output(struct file *file, char __user *user_buf,			    size_t user_len, loff_t *offset);static ssize_t debug_input(struct file *file, const char __user *user_buf,			   size_t user_len, loff_t *offset);static int debug_open(struct inode *inode, struct file *file);static int debug_close(struct inode *inode, struct file *file);static debug_info_t *debug_info_create(const char *name, int pages_per_area,				       int nr_areas, int buf_size, umode_t mode);static void debug_info_get(debug_info_t *);static void debug_info_put(debug_info_t *);static int debug_prolog_level_fn(debug_info_t *id,				 struct debug_view *view, char *out_buf);static int debug_input_level_fn(debug_info_t *id, struct debug_view *view,				struct file *file, const char __user *user_buf,				size_t user_buf_size, loff_t *offset);static int debug_prolog_pages_fn(debug_info_t *id,				 struct debug_view *view, char *out_buf);static int debug_input_pages_fn(debug_info_t *id, struct debug_view *view,				struct file *file, const char __user *user_buf,				size_t user_buf_size, loff_t *offset);static int debug_input_flush_fn(debug_info_t *id, struct debug_view *view,				struct file *file, const char __user *user_buf,				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_sprintf_format_fn(debug_info_t *id, struct debug_view *view,				   char *out_buf, debug_sprintf_entry_t *curr_event); /* globals */ struct debug_view debug_hex_ascii_view = {	"hex_ascii",	NULL,	&debug_dflt_header_fn,	&debug_hex_ascii_format_fn,	NULL,	NULL};EXPORT_SYMBOL(debug_hex_ascii_view); static struct debug_view debug_level_view = {	"level",	&debug_prolog_level_fn,	NULL,	NULL,	&debug_input_level_fn,	NULL}; static struct debug_view debug_pages_view = {	"pages",	&debug_prolog_pages_fn,	NULL,	NULL,	&debug_input_pages_fn,	NULL}; static struct debug_view debug_flush_view = {	"flush",	NULL,	NULL,	NULL,	&debug_input_flush_fn,	NULL}; struct debug_view debug_sprintf_view = {	"sprintf",	NULL,	&debug_dflt_header_fn,	(debug_format_proc_t *)&debug_sprintf_format_fn,	NULL,	NULL};EXPORT_SYMBOL(debug_sprintf_view); /* used by dump analysis tools to determine version of debug feature */static unsigned int __used debug_feature_version = __DEBUG_FEATURE_VERSION; /* static globals */ static debug_info_t *debug_area_first;static debug_info_t *debug_area_last;static DEFINE_MUTEX(debug_mutex); static int initialized;static int debug_critical; static const struct file_operations debug_file_ops = {	.owner	 = THIS_MODULE,	.read	 = debug_output,	.write	 = debug_input,	.open	 = debug_open,	.release = debug_close,	.llseek  = no_llseek,}; static struct dentry *debug_debugfs_root_entry; /* functions */ /* * debug_areas_alloc * - Debug areas are implemented as a threedimensonal array: *   areas[areanumber][pagenumber][pageoffset] */ static debug_entry_t ***debug_areas_alloc(int pages_per_area, int nr_areas){	debug_entry_t ***areas;	int i, j; 	areas = kmalloc_array(nr_areas, sizeof(debug_entry_t **), GFP_KERNEL);	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_NOWARN);		if (!areas[i])			goto fail_malloc_areas2;		for (j = 0; j < pages_per_area; j++) {			areas[i][j] = kzalloc(PAGE_SIZE, GFP_KERNEL);			if (!areas[i][j]) {				for (j--; j >= 0 ; j--)					kfree(areas[i][j]);				kfree(areas[i]);				goto fail_malloc_areas2;			}		}	}	return areas; fail_malloc_areas2:	for (i--; i >= 0; i--) {		for (j = 0; j < pages_per_area; j++)			kfree(areas[i][j]);		kfree(areas[i]);	}	kfree(areas);fail_malloc_areas:	return NULL;} /* * debug_info_alloc * - alloc new debug-info */static debug_info_t *debug_info_alloc(const char *name, int pages_per_area,				      int nr_areas, int buf_size, int level,				      int mode){	debug_info_t *rc; 	/* alloc everything */	rc = kmalloc(sizeof(debug_info_t), GFP_KERNEL);	if (!rc)		goto fail_malloc_rc;	rc->active_entries = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);	if (!rc->active_entries)		goto fail_malloc_active_entries;	rc->active_pages = kcalloc(nr_areas, sizeof(int), GFP_KERNEL);	if (!rc->active_pages)		goto fail_malloc_active_pages;	if ((mode == ALL_AREAS) && (pages_per_area != 0)) {		rc->areas = debug_areas_alloc(pages_per_area, nr_areas);		if (!rc->areas)			goto fail_malloc_areas;	} else {		rc->areas = NULL;	} 	/* initialize members */	spin_lock_init(&rc->lock);	rc->pages_per_area = pages_per_area;	rc->nr_areas	   = nr_areas;	rc->active_area    = 0;	rc->level	   = level;	rc->buf_size	   = buf_size;	rc->entry_size	   = sizeof(debug_entry_t) + buf_size;	strlcpy(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); 	return rc; fail_malloc_areas:	kfree(rc->active_pages);fail_malloc_active_pages:	kfree(rc->active_entries);fail_malloc_active_entries:	kfree(rc);fail_malloc_rc:	return NULL;} /* * debug_areas_free * - free all debug areas */static void debug_areas_free(debug_info_t *db_info){	int i, j; 	if (!db_info->areas)		return;	for (i = 0; i < db_info->nr_areas; i++) {		for (j = 0; j < db_info->pages_per_area; j++)			kfree(db_info->areas[i][j]);		kfree(db_info->areas[i]);	}	kfree(db_info->areas);	db_info->areas = NULL;} /* * debug_info_free * - free memory debug-info */static void debug_info_free(debug_info_t *db_info){	debug_areas_free(db_info);	kfree(db_info->active_entries);	kfree(db_info->active_pages);	kfree(db_info);} /* * debug_info_create * - create new debug-info */ static debug_info_t *debug_info_create(const char *name, int pages_per_area,				       int nr_areas, int buf_size, umode_t mode){	debug_info_t *rc; 	rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,			      DEBUG_DEFAULT_LEVEL, ALL_AREAS);	if (!rc)		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;} /* * debug_info_copy * - copy debug-info */static debug_info_t *debug_info_copy(debug_info_t *in, int mode){	unsigned long flags;	debug_info_t *rc;	int i, j; 	/* get a consistent copy of the debug areas */	do {		rc = debug_info_alloc(in->name, in->pages_per_area,			in->nr_areas, in->buf_size, in->level, mode);		spin_lock_irqsave(&in->lock, flags);		if (!rc)			goto out;		/* has something changed in the meantime ? */		if ((rc->pages_per_area == in->pages_per_area) &&		    (rc->nr_areas == in->nr_areas)) {			break;		}		spin_unlock_irqrestore(&in->lock, flags);		debug_info_free(rc);	} while (1); 	if (mode == NO_AREAS)		goto out; 	for (i = 0; i < in->nr_areas; i++) {		for (j = 0; j < in->pages_per_area; j++)			memcpy(rc->areas[i][j], in->areas[i][j], PAGE_SIZE);	}out:	spin_unlock_irqrestore(&in->lock, flags);	return rc;} /* * debug_info_get * - increments reference count for debug-info */static void debug_info_get(debug_info_t *db_info){	if (db_info)		refcount_inc(&db_info->ref_count);} /* * debug_info_put: * - decreases reference count for debug-info and frees it if necessary */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;		debug_info_free(db_info);	}} /* * debug_format_entry: * - format one debug entry and return size of formated data */static int debug_format_entry(file_private_info_t *p_info){	debug_info_t *id_snap	= p_info->debug_info_snap;	struct debug_view *view = p_info->view;	debug_entry_t *act_entry;	size_t len = 0; 	if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {		/* print prolog */		if (view->prolog_proc)			len += view->prolog_proc(id_snap, view, p_info->temp_buf);		goto out;	}	if (!id_snap->areas) /* this is true, if we have a prolog only view */		goto out;    /* or if 'pages_per_area' is 0 */	act_entry = (debug_entry_t *) ((char *)id_snap->areas[p_info->act_area]				       [p_info->act_page] + p_info->act_entry); 	if (act_entry->clock == 0LL)		goto out; /* empty entry */	if (view->header_proc)		len += view->header_proc(id_snap, view, p_info->act_area,					 act_entry, p_info->temp_buf + len);	if (view->format_proc)		len += view->format_proc(id_snap, view, p_info->temp_buf + len,					 DEBUG_DATA(act_entry));out:	return len;} /* * debug_next_entry: * - goto next entry in p_info */static inline int debug_next_entry(file_private_info_t *p_info){	debug_info_t *id; 	id = p_info->debug_info_snap;	if (p_info->act_entry == DEBUG_PROLOG_ENTRY) {		p_info->act_entry = 0;		p_info->act_page  = 0;		goto out;	}	if (!id->areas)		return 1;	p_info->act_entry += id->entry_size;	/* switch to next page, if we reached the end of the page  */	if (p_info->act_entry > (PAGE_SIZE - id->entry_size)) {		/* next page */		p_info->act_entry = 0;		p_info->act_page += 1;		if ((p_info->act_page % id->pages_per_area) == 0) {			/* next area */			p_info->act_area++;			p_info->act_page = 0;		}		if (p_info->act_area >= id->nr_areas)			return 1;	}out:	return 0;} /* * debug_output: * - called for user read() * - copies formated debug entries to the user buffer */static ssize_t debug_output(struct file *file,		/* file descriptor */			    char __user *user_buf,	/* user buffer */			    size_t len,			/* length of buffer */			    loff_t *offset)		/* offset in the file */{	size_t count = 0;	size_t entry_offset;	file_private_info_t *p_info; 	p_info = (file_private_info_t *) file->private_data;	if (*offset != p_info->offset)		return -EPIPE;	if (p_info->act_area >= p_info->debug_info_snap->nr_areas)		return 0;

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