debug.c

底层驱动开发

}

/*
 * 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;
	entry_offset = p_info->act_entry_offset;
	while(count < len){
		int formatted_line_size;
		int formatted_line_residue;
		int user_buf_residue;
		size_t copy_size;

		formatted_line_size = debug_format_entry(p_info);
		formatted_line_residue = formatted_line_size - entry_offset;
		user_buf_residue = len-count;
		copy_size = min(user_buf_residue, formatted_line_residue);
		if(copy_size){
			if (copy_to_user(user_buf + count, p_info->temp_buf
					+ entry_offset, copy_size))
				return -EFAULT;
			count += copy_size;
			entry_offset += copy_size;
		}
		if(copy_size == formatted_line_residue){
			entry_offset = 0;
			if(debug_next_entry(p_info))
				goto out;
		}
	}
out:
	p_info->offset           = *offset + count;
	p_info->act_entry_offset = entry_offset;
	*offset = p_info->offset;
	return count;
}

/*
 * debug_input:
 * - called for user write()
 * - calls input function of view
 */

static ssize_t
debug_input(struct file *file, const char __user *user_buf, size_t length,
		loff_t *offset)
{
	int rc = 0;
	file_private_info_t *p_info;

	down(&debug_lock);
	p_info = ((file_private_info_t *) file->private_data);
	if (p_info->view->input_proc)
		rc = p_info->view->input_proc(p_info->debug_info_org,
					      p_info->view, file, user_buf,
					      length, offset);
	else
		rc = -EPERM;
	up(&debug_lock);
	return rc;		/* number of input characters */
}

/*
 * debug_open:
 * - called for user open()
 * - copies formated output to private_data area of the file
 *   handle
 */

static int
debug_open(struct inode *inode, struct file *file)
{
	int i = 0, rc = 0;
	file_private_info_t *p_info;
	debug_info_t *debug_info, *debug_info_snapshot;

	down(&debug_lock);
	debug_info = (struct debug_info*)file->f_dentry->d_inode->u.generic_ip;
	/* find debug view */
	for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
		if (!debug_info->views[i])
			continue;
		else if (debug_info->debugfs_entries[i] ==
			 file->f_dentry) {
			goto found;	/* found view ! */
		}
	}
	/* no entry found */
	rc = -EINVAL;
	goto out;

found:

	/* Make snapshot of current debug areas to get it consistent.     */
	/* To copy all the areas is only needed, if we have a view which  */
	/* formats the debug areas. */

	if(!debug_info->views[i]->format_proc &&
		!debug_info->views[i]->header_proc){
		debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
	} else {
		debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
	}

	if(!debug_info_snapshot){
		rc = -ENOMEM;
		goto out;
	}
	p_info = (file_private_info_t *) kmalloc(sizeof(file_private_info_t),
						GFP_KERNEL);
	if(!p_info){
		if(debug_info_snapshot)
			debug_info_free(debug_info_snapshot);
		rc = -ENOMEM;
		goto out;
	}
	p_info->offset = 0;
	p_info->debug_info_snap = debug_info_snapshot;
	p_info->debug_info_org  = debug_info;
	p_info->view = debug_info->views[i];
	p_info->act_area = 0;
	p_info->act_page = 0;
	p_info->act_entry = DEBUG_PROLOG_ENTRY;
	p_info->act_entry_offset = 0;
	file->private_data = p_info;
	debug_info_get(debug_info);
out:
	up(&debug_lock);
	return rc;
}

/*
 * debug_close:
 * - called for user close()
 * - deletes  private_data area of the file handle
 */

static int
debug_close(struct inode *inode, struct file *file)
{
	file_private_info_t *p_info;
	p_info = (file_private_info_t *) file->private_data;
	if(p_info->debug_info_snap)
		debug_info_free(p_info->debug_info_snap);
	debug_info_put(p_info->debug_info_org);
	kfree(file->private_data);
	return 0;		/* success */
}

/*
 * debug_register:
 * - creates and initializes debug area for the caller
 * - returns handle for debug area
 */

debug_info_t*
debug_register (char *name, int pages_per_area, int nr_areas, int buf_size)
{
	debug_info_t *rc = NULL;

	if (!initialized)
		BUG();
	down(&debug_lock);

        /* create new debug_info */

	rc = debug_info_create(name, pages_per_area, nr_areas, buf_size);
	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){
		printk(KERN_ERR "debug: debug_register failed for %s\n",name);
        }
	up(&debug_lock);
	return rc;
}

/*
 * debug_unregister:
 * - give back debug area
 */

void
debug_unregister(debug_info_t * id)
{
	if (!id)
		goto out;
	down(&debug_lock);
	debug_info_put(id);
	up(&debug_lock);

out:
	return;
}

/*
 * debug_set_size:
 * - set area size (number of pages) and number of areas
 */
static int
debug_set_size(debug_info_t* id, int nr_areas, int pages_per_area)
{
	unsigned long flags;
	debug_entry_t *** new_areas;
	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) {
			printk(KERN_WARNING "debug: could not allocate memory "\
					 "for pagenumber: %i\n",pages_per_area);
			rc = -ENOMEM;
			goto out;
		}
	} else {
		new_areas = NULL;
	}
	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);
	spin_unlock_irqrestore(&id->lock,flags);
	printk(KERN_INFO "debug: %s: set new size (%i pages)\n"\
			 ,id->name, pages_per_area);
out:
	return rc;
}

/*
 * debug_set_level:
 * - set actual debug level
 */

void
debug_set_level(debug_info_t* id, int new_level)
{
	unsigned long flags;
	if(!id)
		return;	
	spin_lock_irqsave(&id->lock,flags);
        if(new_level == DEBUG_OFF_LEVEL){
                id->level = DEBUG_OFF_LEVEL;
                printk(KERN_INFO "debug: %s: switched off\n",id->name);
        } else if ((new_level > DEBUG_MAX_LEVEL) || (new_level < 0)) {
                printk(KERN_INFO
                        "debug: %s: level %i is out of range (%i - %i)\n",
                        id->name, new_level, 0, DEBUG_MAX_LEVEL);
        } else {
                id->level = new_level;
        }
	spin_unlock_irqrestore(&id->lock,flags);
}


/*
 * proceed_active_entry:
 * - set active entry to next in the ring buffer
 */

extern inline void
proceed_active_entry(debug_info_t * id)
{
	if ((id->active_entries[id->active_area] += id->entry_size)
	    > (PAGE_SIZE - id->entry_size)){
		id->active_entries[id->active_area] = 0;
		id->active_pages[id->active_area] =
			(id->active_pages[id->active_area] + 1) %
			id->pages_per_area;
	}
}

/*
 * proceed_active_area:
 * - set active area to next in the ring buffer
 */

extern inline void
proceed_active_area(debug_info_t * id)
{
	id->active_area++;
	id->active_area = id->active_area % id->nr_areas;
}

/*
 * get_active_entry:
 */

extern inline debug_entry_t*
get_active_entry(debug_info_t * id)
{
	return (debug_entry_t *) (((char *) id->areas[id->active_area]
					[id->active_pages[id->active_area]]) +
					id->active_entries[id->active_area]);
}

/*
 * debug_finish_entry:
 * - set timestamp, caller address, cpu number etc.
 */

extern inline void
debug_finish_entry(debug_info_t * id, debug_entry_t* active, int level,
			int exception)
{
	active->id.stck = get_clock();
	active->id.fields.cpuid = smp_processor_id();
	active->caller = __builtin_return_address(0);
	active->id.fields.exception = exception;
	active->id.fields.level     = level;
	proceed_active_entry(id);
	if(exception)
		proceed_active_area(id);
}

static int debug_stoppable=1;
static int debug_active=1;

#define CTL_S390DBF 5677
#define CTL_S390DBF_STOPPABLE 5678
#define CTL_S390DBF_ACTIVE 5679

/*
 * proc handler for the running debug_active sysctl
 * always allow read, allow write only if debug_stoppable is set or
 * if debug_active is already off
 */
static int
s390dbf_procactive(ctl_table *table, int write, struct file *filp,
                     void __user *buffer, size_t *lenp, loff_t *ppos)
{
	if (!write || debug_stoppable || !debug_active)
		return proc_dointvec(table, write, filp, buffer, lenp, ppos);
	else
		return 0;
}


static struct ctl_table s390dbf_table[] = {
	{
		.ctl_name       = CTL_S390DBF_STOPPABLE,
		.procname       = "debug_stoppable",
		.data		= &debug_stoppable,
		.maxlen		= sizeof(int),
		.mode           = S_IRUGO | S_IWUSR,
		.proc_handler   = &proc_dointvec,
		.strategy	= &sysctl_intvec,
	},
	 {
		.ctl_name       = CTL_S390DBF_ACTIVE,
		.procname       = "debug_active",
		.data		= &debug_active,
		.maxlen		= sizeof(int),
		.mode           = S_IRUGO | S_IWUSR,
		.proc_handler   = &s390dbf_procactive,
		.strategy	= &sysctl_intvec,
	},
	{ .ctl_name = 0 }
};

static struct ctl_table s390dbf_dir_table[] = {
	{
		.ctl_name       = CTL_S390DBF,
		.procname       = "s390dbf",
		.maxlen         = 0,
		.mode           = S_IRUGO | S_IXUGO,
		.child          = s390dbf_table,
	},
	{ .ctl_name = 0 }
};

struct ctl_table_header *s390dbf_sysctl_header;

void
debug_stop_all(void)
{
	if (debug_stoppable)
		debug_active = 0;
}


/*
 * debug_event_common:
 * - write debug entry with given size
 */

debug_entry_t*
debug_event_common(debug_info_t * id, int level, const void *buf, int len)
{
	unsigned long flags;
	debug_entry_t *active;

	if (!debug_active || !id->areas)
		return NULL;
	spin_lock_irqsave(&id->lock, flags);
	active = get_active_entry(id);
	memset(DEBUG_DATA(active), 0, id->buf_size);
	memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
	debug_finish_entry(id, active, level, 0);
	spin_unlock_irqrestore(&id->lock, flags);

	return active;
}

/*
 * debug_exception_common:
 * - write debug entry with given size and switch to next debug area
 */

debug_entry_t
*debug_exception_common(debug_info_t * id, int level, const void *buf, int len)
{
	unsigned long flags;
	debug_entry_t *active;

	if (!debug_active || !id->areas)
		return NULL;
	spin_lock_irqsave(&id->lock, flags);
	active = get_active_entry(id);
	memset(DEBUG_DATA(active), 0, id->buf_size);
	memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
	debug_finish_entry(id, active, level, 1);
	spin_unlock_irqrestore(&id->lock, flags);

	return active;
}

/*
 * counts arguments in format string for sprintf view
 */

extern inline int
debug_count_numargs(char *string)
{
	int numargs=0;

	while(*string) {
		if(*string++=='%')
			numargs++;
	}
	return(numargs);
}

/*
 * debug_sprintf_event:
 */

debug_entry_t*
debug_sprintf_event(debug_info_t* id, int level,char *string,...)
{
	va_list   ap;
	int numargs,idx;
	unsigned long flags;
	debug_sprintf_entry_t *curr_event;
	debug_entry_t *active;

	if((!id) || (level > id->level))
		return NULL;
	if (!debug_active || !id->areas)
		return NULL;
	numargs=debug_count_numargs(string);

	spin_lock_irqsave(&id->lock, flags);
	active = get_active_entry(id);
	curr_event=(debug_sprintf_entry_t *) DEBUG_DATA(active);
	va_start(ap,string);
	curr_event->string=string;
	for(idx=0;idx<min(numargs,(int)(id->buf_size / sizeof(long))-1);idx++)
		curr_event->args[idx]=va_arg(ap,long);
	va_end(ap);
	debug_finish_entry(id, active, level, 0);
	spin_unlock_irqrestore(&id->lock, flags);

	return active;
}

/*
 * debug_sprintf_exception:
 */

debug_entry_t*
debug_sprintf_exception(debug_info_t* id, int level,char *string,...)
{
	va_list   ap;
	int numargs,idx;
	unsigned long flags;
	debug_sprintf_entry_t *curr_event;
	debug_entry_t *active;

	if((!id) || (level > id->level))
		return NULL;
	if (!debug_active || !id->areas)