[deliverable/linux.git] / drivers / s390 / char / monreader.c

/*
 * drivers/s390/char/monreader.c
 *
 * Character device driver for reading z/VM *MONITOR service records.
 *
 *   Copyright IBM Corp. 2004, 2008
 *   Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
 */

#define KMSG_COMPONENT "monreader"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/ctype.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/poll.h>
#include <net/iucv/iucv.h>
#include <asm/uaccess.h>
#include <asm/ebcdic.h>
#include <asm/extmem.h>


#define MON_COLLECT_SAMPLE 0x80
#define MON_COLLECT_EVENT  0x40
#define MON_SERVICE	   "*MONITOR"
#define MON_IN_USE	   0x01
#define MON_MSGLIM	   255

static char mon_dcss_name[9] = "MONDCSS\0";

struct mon_msg {
	u32 pos;
	u32 mca_offset;
	struct iucv_message msg;
	char msglim_reached;
	char replied_msglim;
};

struct mon_private {
	struct iucv_path *path;
	struct mon_msg *msg_array[MON_MSGLIM];
	unsigned int   write_index;
	unsigned int   read_index;
	atomic_t msglim_count;
	atomic_t read_ready;
	atomic_t iucv_connected;
	atomic_t iucv_severed;
};

static unsigned long mon_in_use = 0;

static unsigned long mon_dcss_start;
static unsigned long mon_dcss_end;

static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);

static u8 user_data_connect[16] = {
	/* Version code, must be 0x01 for shared mode */
	0x01,
	/* what to collect */
	MON_COLLECT_SAMPLE | MON_COLLECT_EVENT,
	/* DCSS name in EBCDIC, 8 bytes padded with blanks */
	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
};

static u8 user_data_sever[16] = {
	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
};


/******************************************************************************
 *                             helper functions                               *
 *****************************************************************************/
/*
 * Create the 8 bytes EBCDIC DCSS segment name from
 * an ASCII name, incl. padding
 */
static void dcss_mkname(char *ascii_name, char *ebcdic_name)
{
	int i;

	for (i = 0; i < 8; i++) {
		if (ascii_name[i] == '\0')
			break;
		ebcdic_name[i] = toupper(ascii_name[i]);
	};
	for (; i < 8; i++)
		ebcdic_name[i] = ' ';
	ASCEBC(ebcdic_name, 8);
}

static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
{
	return *(u32 *) &monmsg->msg.rmmsg;
}

static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
{
	return *(u32 *) &monmsg->msg.rmmsg[4];
}

static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
{
	return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index);
}

static inline u32 mon_mca_size(struct mon_msg *monmsg)
{
	return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
}

static inline u32 mon_rec_start(struct mon_msg *monmsg)
{
	return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
}

static inline u32 mon_rec_end(struct mon_msg *monmsg)
{
	return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
}

static int mon_check_mca(struct mon_msg *monmsg)
{
	if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
	    (mon_rec_start(monmsg) < mon_dcss_start) ||
	    (mon_rec_end(monmsg) > mon_dcss_end) ||
	    (mon_mca_type(monmsg, 0) == 0) ||
	    (mon_mca_size(monmsg) % 12 != 0) ||
	    (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
	    (mon_mca_end(monmsg) > mon_dcss_end) ||
	    (mon_mca_start(monmsg) < mon_dcss_start) ||
	    ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
		return -EINVAL;
	return 0;
}

static int mon_send_reply(struct mon_msg *monmsg,
			  struct mon_private *monpriv)
{
	int rc;

	rc = iucv_message_reply(monpriv->path, &monmsg->msg,
				IUCV_IPRMDATA, NULL, 0);
	atomic_dec(&monpriv->msglim_count);
	if (likely(!monmsg->msglim_reached)) {
		monmsg->pos = 0;
		monmsg->mca_offset = 0;
		monpriv->read_index = (monpriv->read_index + 1) %
				      MON_MSGLIM;
		atomic_dec(&monpriv->read_ready);
	} else
		monmsg->replied_msglim = 1;
	if (rc) {
		pr_err("Reading monitor data failed with rc=%i\n", rc);
		return -EIO;
	}
	return 0;
}

static void mon_free_mem(struct mon_private *monpriv)
{
	int i;

	for (i = 0; i < MON_MSGLIM; i++)
		if (monpriv->msg_array[i])
			kfree(monpriv->msg_array[i]);
	kfree(monpriv);
}

static struct mon_private *mon_alloc_mem(void)
{
	int i;
	struct mon_private *monpriv;

	monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
	if (!monpriv)
		return NULL;
	for (i = 0; i < MON_MSGLIM; i++) {
		monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
						    GFP_KERNEL);
		if (!monpriv->msg_array[i]) {
			mon_free_mem(monpriv);
			return NULL;
		}
	}
	return monpriv;
}

static inline void mon_next_mca(struct mon_msg *monmsg)
{
	if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
		return;
	monmsg->mca_offset += 12;
	monmsg->pos = 0;
}

static struct mon_msg *mon_next_message(struct mon_private *monpriv)
{
	struct mon_msg *monmsg;

	if (!atomic_read(&monpriv->read_ready))
		return NULL;
	monmsg = monpriv->msg_array[monpriv->read_index];
	if (unlikely(monmsg->replied_msglim)) {
		monmsg->replied_msglim = 0;
		monmsg->msglim_reached = 0;
		monmsg->pos = 0;
		monmsg->mca_offset = 0;
		monpriv->read_index = (monpriv->read_index + 1) %
				      MON_MSGLIM;
		atomic_dec(&monpriv->read_ready);
		return ERR_PTR(-EOVERFLOW);
	}
	return monmsg;
}


/******************************************************************************
 *                               IUCV handler                                 *
 *****************************************************************************/
static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
{
	struct mon_private *monpriv = path->private;

	atomic_set(&monpriv->iucv_connected, 1);
	wake_up(&mon_conn_wait_queue);
}

static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
{
	struct mon_private *monpriv = path->private;

	pr_err("z/VM *MONITOR system service disconnected with rc=%i\n",
	       ipuser[0]);
	iucv_path_sever(path, NULL);
	atomic_set(&monpriv->iucv_severed, 1);
	wake_up(&mon_conn_wait_queue);
	wake_up_interruptible(&mon_read_wait_queue);
}

static void mon_iucv_message_pending(struct iucv_path *path,
				     struct iucv_message *msg)
{
	struct mon_private *monpriv = path->private;

	memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
	       msg, sizeof(*msg));
	if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
		pr_warning("The read queue for monitor data is full\n");
		monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
	}
	monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
	atomic_inc(&monpriv->read_ready);
	wake_up_interruptible(&mon_read_wait_queue);
}

static struct iucv_handler monreader_iucv_handler = {
	.path_complete	 = mon_iucv_path_complete,
	.path_severed	 = mon_iucv_path_severed,
	.message_pending = mon_iucv_message_pending,
};

/******************************************************************************
 *                               file operations                              *
 *****************************************************************************/
static int mon_open(struct inode *inode, struct file *filp)
{
	struct mon_private *monpriv;
	int rc;

	/*
	 * only one user allowed
	 */
	lock_kernel();
	rc = -EBUSY;
	if (test_and_set_bit(MON_IN_USE, &mon_in_use))
		goto out;

	rc = -ENOMEM;
	monpriv = mon_alloc_mem();
	if (!monpriv)
		goto out_use;

	/*
	 * Connect to *MONITOR service
	 */
	monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
	if (!monpriv->path)
		goto out_priv;
	rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
			       MON_SERVICE, NULL, user_data_connect, monpriv);
	if (rc) {
		pr_err("Connecting to the z/VM *MONITOR system service "
		       "failed with rc=%i\n", rc);
		rc = -EIO;
		goto out_path;
	}
	/*
	 * Wait for connection confirmation
	 */
	wait_event(mon_conn_wait_queue,
		   atomic_read(&monpriv->iucv_connected) ||
		   atomic_read(&monpriv->iucv_severed));
	if (atomic_read(&monpriv->iucv_severed)) {
		atomic_set(&monpriv->iucv_severed, 0);
		atomic_set(&monpriv->iucv_connected, 0);
		rc = -EIO;
		goto out_path;
	}
	filp->private_data = monpriv;
	unlock_kernel();
	return nonseekable_open(inode, filp);

out_path:
	kfree(monpriv->path);
out_priv:
	mon_free_mem(monpriv);
out_use:
	clear_bit(MON_IN_USE, &mon_in_use);
out:
	unlock_kernel();
	return rc;
}

static int mon_close(struct inode *inode, struct file *filp)
{
	int rc, i;
	struct mon_private *monpriv = filp->private_data;

	/*
	 * Close IUCV connection and unregister
	 */
	rc = iucv_path_sever(monpriv->path, user_data_sever);
	if (rc)
		pr_warning("Disconnecting the z/VM *MONITOR system service "
			   "failed with rc=%i\n", rc);

	atomic_set(&monpriv->iucv_severed, 0);
	atomic_set(&monpriv->iucv_connected, 0);
	atomic_set(&monpriv->read_ready, 0);
	atomic_set(&monpriv->msglim_count, 0);
	monpriv->write_index  = 0;
	monpriv->read_index   = 0;

	for (i = 0; i < MON_MSGLIM; i++)
		kfree(monpriv->msg_array[i]);
	kfree(monpriv);
	clear_bit(MON_IN_USE, &mon_in_use);
	return 0;
}

static ssize_t mon_read(struct file *filp, char __user *data,
			size_t count, loff_t *ppos)
{
	struct mon_private *monpriv = filp->private_data;
	struct mon_msg *monmsg;
	int ret;
	u32 mce_start;

	monmsg = mon_next_message(monpriv);
	if (IS_ERR(monmsg))
		return PTR_ERR(monmsg);

	if (!monmsg) {
		if (filp->f_flags & O_NONBLOCK)
			return -EAGAIN;
		ret = wait_event_interruptible(mon_read_wait_queue,
					atomic_read(&monpriv->read_ready) ||
					atomic_read(&monpriv->iucv_severed));
		if (ret)
			return ret;
		if (unlikely(atomic_read(&monpriv->iucv_severed)))
			return -EIO;
		monmsg = monpriv->msg_array[monpriv->read_index];
	}

	if (!monmsg->pos)
		monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
	if (mon_check_mca(monmsg))
		goto reply;

	/* read monitor control element (12 bytes) first */
	mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
	if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
		count = min(count, (size_t) mce_start + 12 - monmsg->pos);
		ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
				   count);
		if (ret)
			return -EFAULT;
		monmsg->pos += count;
		if (monmsg->pos == mce_start + 12)
			monmsg->pos = mon_rec_start(monmsg);
		goto out_copy;
	}

	/* read records */
	if (monmsg->pos <= mon_rec_end(monmsg)) {
		count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
					    + 1);
		ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
				   count);
		if (ret)
			return -EFAULT;
		monmsg->pos += count;
		if (monmsg->pos > mon_rec_end(monmsg))
			mon_next_mca(monmsg);
		goto out_copy;
	}
reply:
	ret = mon_send_reply(monmsg, monpriv);
	return ret;

out_copy:
	*ppos += count;
	return count;
}

static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p)
{
	struct mon_private *monpriv = filp->private_data;

	poll_wait(filp, &mon_read_wait_queue, p);
	if (unlikely(atomic_read(&monpriv->iucv_severed)))
		return POLLERR;
	if (atomic_read(&monpriv->read_ready))
		return POLLIN | POLLRDNORM;
	return 0;
}

static const struct file_operations mon_fops = {
	.owner   = THIS_MODULE,
	.open    = &mon_open,
	.release = &mon_close,
	.read    = &mon_read,
	.poll    = &mon_poll,
};

static struct miscdevice mon_dev = {
	.name       = "monreader",
	.fops       = &mon_fops,
	.minor      = MISC_DYNAMIC_MINOR,
};

/******************************************************************************
 *                              module init/exit                              *
 *****************************************************************************/
static int __init mon_init(void)
{
	int rc;

	if (!MACHINE_IS_VM) {
		pr_err("The z/VM *MONITOR record device driver cannot be "
		       "loaded without z/VM\n");
		return -ENODEV;
	}

	/*
	 * Register with IUCV and connect to *MONITOR service
	 */
	rc = iucv_register(&monreader_iucv_handler, 1);
	if (rc) {
		pr_err("The z/VM *MONITOR record device driver failed to "
		       "register with IUCV\n");
		return rc;
	}

	rc = segment_type(mon_dcss_name);
	if (rc < 0) {
		segment_warning(rc, mon_dcss_name);
		goto out_iucv;
	}
	if (rc != SEG_TYPE_SC) {
		pr_err("The specified *MONITOR DCSS %s does not have the "
		       "required type SC\n", mon_dcss_name);
		rc = -EINVAL;
		goto out_iucv;
	}

	rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
			  &mon_dcss_start, &mon_dcss_end);
	if (rc < 0) {
		segment_warning(rc, mon_dcss_name);
		rc = -EINVAL;
		goto out_iucv;
	}
	dcss_mkname(mon_dcss_name, &user_data_connect[8]);

	rc = misc_register(&mon_dev);
	if (rc < 0 )
		goto out;
	return 0;

out:
	segment_unload(mon_dcss_name);
out_iucv:
	iucv_unregister(&monreader_iucv_handler, 1);
	return rc;
}

static void __exit mon_exit(void)
{
	segment_unload(mon_dcss_name);
	WARN_ON(misc_deregister(&mon_dev) != 0);
	iucv_unregister(&monreader_iucv_handler, 1);
	return;
}


module_init(mon_init);
module_exit(mon_exit);

module_param_string(mondcss, mon_dcss_name, 9, 0444);
MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
		 "service, max. 8 chars. Default is MONDCSS");

MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
MODULE_DESCRIPTION("Character device driver for reading z/VM "
		   "monitor service records.");
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* drivers/s390/char/monreader.c
	3	*
	4	* Character device driver for reading z/VM *MONITOR service records.
	5	*
2ca5b6e2 GS	6	* Copyright IBM Corp. 2004, 2008
2ca5b6e2 GS	7	* Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
1da177e4 LT	8	*/
1da177e4 LT	9
a4f5a299 GS	10	#define KMSG_COMPONENT "monreader"
	11	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
	12
1da177e4 LT	13	#include <linux/module.h>
	14	#include <linux/moduleparam.h>
	15	#include <linux/init.h>
6ce46a43	16	#include <linux/smp_lock.h>
1da177e4 LT	17	#include <linux/errno.h>
	18	#include <linux/types.h>
	19	#include <linux/kernel.h>
	20	#include <linux/miscdevice.h>
	21	#include <linux/ctype.h>
	22	#include <linux/spinlock.h>
	23	#include <linux/interrupt.h>
2ca5b6e2 GS	24	#include <linux/poll.h>
2ca5b6e2 GS	25	#include <net/iucv/iucv.h>
1da177e4 LT	26	#include <asm/uaccess.h>
	27	#include <asm/ebcdic.h>
	28	#include <asm/extmem.h>
1da177e4	29
1da177e4 LT	30
	31	#define MON_COLLECT_SAMPLE 0x80
	32	#define MON_COLLECT_EVENT 0x40
	33	#define MON_SERVICE "*MONITOR"
	34	#define MON_IN_USE 0x01
	35	#define MON_MSGLIM 255
	36
	37	static char mon_dcss_name[9] = "MONDCSS\0";
	38
	39	struct mon_msg {
	40	u32 pos;
	41	u32 mca_offset;
c667aac8	42	struct iucv_message msg;
1da177e4 LT	43	char msglim_reached;
	44	char replied_msglim;
	45	};
	46
	47	struct mon_private {
c667aac8	48	struct iucv_path *path;
1da177e4 LT	49	struct mon_msg *msg_array[MON_MSGLIM];
	50	unsigned int write_index;
	51	unsigned int read_index;
	52	atomic_t msglim_count;
	53	atomic_t read_ready;
	54	atomic_t iucv_connected;
	55	atomic_t iucv_severed;
	56	};
	57
	58	static unsigned long mon_in_use = 0;
	59
	60	static unsigned long mon_dcss_start;
	61	static unsigned long mon_dcss_end;
	62
	63	static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
	64	static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
	65
1da177e4 LT	66	static u8 user_data_connect[16] = {
	67	/* Version code, must be 0x01 for shared mode */
	68	0x01,
	69	/* what to collect */
	70	MON_COLLECT_SAMPLE \| MON_COLLECT_EVENT,
	71	/* DCSS name in EBCDIC, 8 bytes padded with blanks */
	72	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	73	0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	74	};
	75
	76	static u8 user_data_sever[16] = {
	77	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	78	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	79	};
	80
	81
	82	/******************************************************************************
	83	* helper functions *
	84	*****************************************************************************/
	85	/*
	86	* Create the 8 bytes EBCDIC DCSS segment name from
	87	* an ASCII name, incl. padding
	88	*/
9b0c455a	89	static void dcss_mkname(char ascii_name, char ebcdic_name)
1da177e4 LT	90	{
	91	int i;
	92
	93	for (i = 0; i < 8; i++) {
	94	if (ascii_name[i] == '\0')
	95	break;
	96	ebcdic_name[i] = toupper(ascii_name[i]);
	97	};
	98	for (; i < 8; i++)
	99	ebcdic_name[i] = ' ';
	100	ASCEBC(ebcdic_name, 8);
	101	}
	102
c667aac8	103	static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
1da177e4	104	{
c667aac8	105	return (u32 ) &monmsg->msg.rmmsg;
1da177e4 LT	106	}
1da177e4 LT	107
c667aac8	108	static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
1da177e4	109	{
c667aac8	110	return (u32 ) &monmsg->msg.rmmsg[4];
1da177e4 LT	111	}
1da177e4 LT	112
c667aac8	113	static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
1da177e4 LT	114	{
	115	return ((u8 ) mon_mca_start(monmsg) + monmsg->mca_offset + index);
	116	}
	117
c667aac8	118	static inline u32 mon_mca_size(struct mon_msg *monmsg)
1da177e4 LT	119	{
	120	return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
	121	}
	122
c667aac8	123	static inline u32 mon_rec_start(struct mon_msg *monmsg)
1da177e4 LT	124	{
	125	return ((u32 ) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
	126	}
	127
c667aac8	128	static inline u32 mon_rec_end(struct mon_msg *monmsg)
1da177e4 LT	129	{
	130	return ((u32 ) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
	131	}
	132
9b0c455a	133	static int mon_check_mca(struct mon_msg *monmsg)
1da177e4 LT	134	{
	135	if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) \|\|
	136	(mon_rec_start(monmsg) < mon_dcss_start) \|\|
	137	(mon_rec_end(monmsg) > mon_dcss_end) \|\|
	138	(mon_mca_type(monmsg, 0) == 0) \|\|
	139	(mon_mca_size(monmsg) % 12 != 0) \|\|
	140	(mon_mca_end(monmsg) <= mon_mca_start(monmsg)) \|\|
	141	(mon_mca_end(monmsg) > mon_dcss_end) \|\|
	142	(mon_mca_start(monmsg) < mon_dcss_start) \|\|
	143	((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
1da177e4	144	return -EINVAL;
1da177e4 LT	145	return 0;
	146	}
	147
9b0c455a MS	148	static int mon_send_reply(struct mon_msg *monmsg,
9b0c455a MS	149	struct mon_private *monpriv)
1da177e4	150	{
1da177e4 LT	151	int rc;
1da177e4 LT	152
c667aac8 MS	153	rc = iucv_message_reply(monpriv->path, &monmsg->msg,
c667aac8 MS	154	IUCV_IPRMDATA, NULL, 0);
1da177e4 LT	155	atomic_dec(&monpriv->msglim_count);
	156	if (likely(!monmsg->msglim_reached)) {
	157	monmsg->pos = 0;
	158	monmsg->mca_offset = 0;
	159	monpriv->read_index = (monpriv->read_index + 1) %
	160	MON_MSGLIM;
	161	atomic_dec(&monpriv->read_ready);
	162	} else
	163	monmsg->replied_msglim = 1;
	164	if (rc) {
a4f5a299	165	pr_err("Reading monitor data failed with rc=%i\n", rc);
1da177e4 LT	166	return -EIO;
	167	}
	168	return 0;
	169	}
	170
9b0c455a	171	static void mon_free_mem(struct mon_private *monpriv)
c667aac8 MS	172	{
	173	int i;
	174
	175	for (i = 0; i < MON_MSGLIM; i++)
	176	if (monpriv->msg_array[i])
	177	kfree(monpriv->msg_array[i]);
	178	kfree(monpriv);
	179	}
	180
9b0c455a	181	static struct mon_private *mon_alloc_mem(void)
1da177e4	182	{
c667aac8	183	int i;
1da177e4 LT	184	struct mon_private *monpriv;
1da177e4 LT	185
88abaab4	186	monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
2ca5b6e2	187	if (!monpriv)
1da177e4	188	return NULL;
1da177e4	189	for (i = 0; i < MON_MSGLIM; i++) {
88abaab4	190	monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
1da177e4 LT	191	GFP_KERNEL);
1da177e4 LT	192	if (!monpriv->msg_array[i]) {
c667aac8	193	mon_free_mem(monpriv);
1da177e4 LT	194	return NULL;
1da177e4 LT	195	}
1da177e4 LT	196	}
	197	return monpriv;
	198	}
	199
c667aac8	200	static inline void mon_next_mca(struct mon_msg *monmsg)
1da177e4 LT	201	{
	202	if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
	203	return;
1da177e4 LT	204	monmsg->mca_offset += 12;
	205	monmsg->pos = 0;
	206	}
	207
9b0c455a	208	static struct mon_msg mon_next_message(struct mon_private monpriv)
1da177e4 LT	209	{
	210	struct mon_msg *monmsg;
	211
	212	if (!atomic_read(&monpriv->read_ready))
	213	return NULL;
	214	monmsg = monpriv->msg_array[monpriv->read_index];
	215	if (unlikely(monmsg->replied_msglim)) {
	216	monmsg->replied_msglim = 0;
	217	monmsg->msglim_reached = 0;
	218	monmsg->pos = 0;
	219	monmsg->mca_offset = 0;
1da177e4 LT	220	monpriv->read_index = (monpriv->read_index + 1) %
	221	MON_MSGLIM;
	222	atomic_dec(&monpriv->read_ready);
	223	return ERR_PTR(-EOVERFLOW);
	224	}
	225	return monmsg;
	226	}
	227
	228
	229	/******************************************************************************
	230	* IUCV handler *
	231	*****************************************************************************/
c667aac8	232	static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
1da177e4	233	{
c667aac8	234	struct mon_private *monpriv = path->private;
1da177e4	235
1da177e4 LT	236	atomic_set(&monpriv->iucv_connected, 1);
	237	wake_up(&mon_conn_wait_queue);
	238	}
	239
c667aac8	240	static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
1da177e4	241	{
c667aac8	242	struct mon_private *monpriv = path->private;
1da177e4	243
a4f5a299 GS	244	pr_err("z/VM *MONITOR system service disconnected with rc=%i\n",
a4f5a299 GS	245	ipuser[0]);
c667aac8	246	iucv_path_sever(path, NULL);
1da177e4 LT	247	atomic_set(&monpriv->iucv_severed, 1);
	248	wake_up(&mon_conn_wait_queue);
	249	wake_up_interruptible(&mon_read_wait_queue);
	250	}
	251
c667aac8 MS	252	static void mon_iucv_message_pending(struct iucv_path *path,
c667aac8 MS	253	struct iucv_message *msg)
1da177e4	254	{
c667aac8	255	struct mon_private *monpriv = path->private;
1da177e4	256
c667aac8 MS	257	memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
c667aac8 MS	258	msg, sizeof(*msg));
1da177e4	259	if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
a4f5a299	260	pr_warning("The read queue for monitor data is full\n");
1da177e4 LT	261	monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
	262	}
	263	monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
	264	atomic_inc(&monpriv->read_ready);
	265	wake_up_interruptible(&mon_read_wait_queue);
	266	}
	267
c667aac8 MS	268	static struct iucv_handler monreader_iucv_handler = {
	269	.path_complete = mon_iucv_path_complete,
	270	.path_severed = mon_iucv_path_severed,
	271	.message_pending = mon_iucv_message_pending,
1da177e4 LT	272	};
	273
	274	/******************************************************************************
	275	* file operations *
	276	*****************************************************************************/
c667aac8	277	static int mon_open(struct inode inode, struct file filp)
1da177e4	278	{
1da177e4	279	struct mon_private *monpriv;
c667aac8	280	int rc;
1da177e4 LT	281
	282	/*
	283	* only one user allowed
	284	*/
6ce46a43	285	lock_kernel();
c667aac8	286	rc = -EBUSY;
1da177e4	287	if (test_and_set_bit(MON_IN_USE, &mon_in_use))
c667aac8	288	goto out;
1da177e4	289
c667aac8	290	rc = -ENOMEM;
1da177e4 LT	291	monpriv = mon_alloc_mem();
1da177e4 LT	292	if (!monpriv)
c667aac8	293	goto out_use;
1da177e4 LT	294
1da177e4 LT	295	/*
c667aac8	296	* Connect to *MONITOR service
1da177e4	297	*/
c667aac8 MS	298	monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
	299	if (!monpriv->path)
	300	goto out_priv;
	301	rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
	302	MON_SERVICE, NULL, user_data_connect, monpriv);
1da177e4	303	if (rc) {
a4f5a299 GS	304	pr_err("Connecting to the z/VM *MONITOR system service "
a4f5a299 GS	305	"failed with rc=%i\n", rc);
1da177e4	306	rc = -EIO;
c667aac8	307	goto out_path;
1da177e4 LT	308	}
	309	/*
	310	* Wait for connection confirmation
	311	*/
	312	wait_event(mon_conn_wait_queue,
	313	atomic_read(&monpriv->iucv_connected) \|\|
	314	atomic_read(&monpriv->iucv_severed));
	315	if (atomic_read(&monpriv->iucv_severed)) {
	316	atomic_set(&monpriv->iucv_severed, 0);
	317	atomic_set(&monpriv->iucv_connected, 0);
	318	rc = -EIO;
c667aac8	319	goto out_path;
1da177e4	320	}
1da177e4	321	filp->private_data = monpriv;
6ce46a43	322	unlock_kernel();
1da177e4 LT	323	return nonseekable_open(inode, filp);
1da177e4 LT	324
c667aac8 MS	325	out_path:
	326	kfree(monpriv->path);
	327	out_priv:
	328	mon_free_mem(monpriv);
	329	out_use:
1da177e4	330	clear_bit(MON_IN_USE, &mon_in_use);
c667aac8	331	out:
6ce46a43	332	unlock_kernel();
1da177e4 LT	333	return rc;
	334	}
	335
c667aac8	336	static int mon_close(struct inode inode, struct file filp)
1da177e4 LT	337	{
	338	int rc, i;
	339	struct mon_private *monpriv = filp->private_data;
	340
	341	/*
	342	* Close IUCV connection and unregister
	343	*/
c667aac8	344	rc = iucv_path_sever(monpriv->path, user_data_sever);
1da177e4	345	if (rc)
a4f5a299 GS	346	pr_warning("Disconnecting the z/VM *MONITOR system service "
a4f5a299 GS	347	"failed with rc=%i\n", rc);
1da177e4	348
1da177e4 LT	349	atomic_set(&monpriv->iucv_severed, 0);
	350	atomic_set(&monpriv->iucv_connected, 0);
	351	atomic_set(&monpriv->read_ready, 0);
	352	atomic_set(&monpriv->msglim_count, 0);
	353	monpriv->write_index = 0;
	354	monpriv->read_index = 0;
	355
	356	for (i = 0; i < MON_MSGLIM; i++)
	357	kfree(monpriv->msg_array[i]);
	358	kfree(monpriv);
	359	clear_bit(MON_IN_USE, &mon_in_use);
	360	return 0;
	361	}
	362
c667aac8 MS	363	static ssize_t mon_read(struct file filp, char __user data,
c667aac8 MS	364	size_t count, loff_t *ppos)
1da177e4 LT	365	{
	366	struct mon_private *monpriv = filp->private_data;
	367	struct mon_msg *monmsg;
	368	int ret;
	369	u32 mce_start;
	370
	371	monmsg = mon_next_message(monpriv);
	372	if (IS_ERR(monmsg))
	373	return PTR_ERR(monmsg);
	374
	375	if (!monmsg) {
	376	if (filp->f_flags & O_NONBLOCK)
	377	return -EAGAIN;
	378	ret = wait_event_interruptible(mon_read_wait_queue,
	379	atomic_read(&monpriv->read_ready) \|\|
	380	atomic_read(&monpriv->iucv_severed));
	381	if (ret)
	382	return ret;
	383	if (unlikely(atomic_read(&monpriv->iucv_severed)))
	384	return -EIO;
	385	monmsg = monpriv->msg_array[monpriv->read_index];
	386	}
	387
2ca5b6e2	388	if (!monmsg->pos)
1da177e4	389	monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
1da177e4 LT	390	if (mon_check_mca(monmsg))
	391	goto reply;
	392
	393	/* read monitor control element (12 bytes) first */
	394	mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
	395	if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
	396	count = min(count, (size_t) mce_start + 12 - monmsg->pos);
	397	ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
	398	count);
	399	if (ret)
	400	return -EFAULT;
	401	monmsg->pos += count;
	402	if (monmsg->pos == mce_start + 12)
	403	monmsg->pos = mon_rec_start(monmsg);
	404	goto out_copy;
	405	}
	406
	407	/* read records */
	408	if (monmsg->pos <= mon_rec_end(monmsg)) {
	409	count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
	410	+ 1);
	411	ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
	412	count);
	413	if (ret)
	414	return -EFAULT;
	415	monmsg->pos += count;
	416	if (monmsg->pos > mon_rec_end(monmsg))
	417	mon_next_mca(monmsg);
	418	goto out_copy;
	419	}
	420	reply:
	421	ret = mon_send_reply(monmsg, monpriv);
	422	return ret;
	423
	424	out_copy:
	425	*ppos += count;
	426	return count;
	427	}
	428
c667aac8	429	static unsigned int mon_poll(struct file filp, struct poll_table_struct p)
1da177e4 LT	430	{
	431	struct mon_private *monpriv = filp->private_data;
	432
	433	poll_wait(filp, &mon_read_wait_queue, p);
	434	if (unlikely(atomic_read(&monpriv->iucv_severed)))
	435	return POLLERR;
	436	if (atomic_read(&monpriv->read_ready))
	437	return POLLIN \| POLLRDNORM;
	438	return 0;
	439	}
	440
d54b1fdb	441	static const struct file_operations mon_fops = {
1da177e4 LT	442	.owner = THIS_MODULE,
	443	.open = &mon_open,
	444	.release = &mon_close,
	445	.read = &mon_read,
	446	.poll = &mon_poll,
	447	};
	448
	449	static struct miscdevice mon_dev = {
	450	.name = "monreader",
1da177e4 LT	451	.fops = &mon_fops,
	452	.minor = MISC_DYNAMIC_MINOR,
	453	};
	454
	455	/******************************************************************************
	456	* module init/exit *
	457	*****************************************************************************/
c667aac8	458	static int __init mon_init(void)
1da177e4 LT	459	{
	460	int rc;
	461
	462	if (!MACHINE_IS_VM) {
a4f5a299 GS	463	pr_err("The z/VM *MONITOR record device driver cannot be "
a4f5a299 GS	464	"loaded without z/VM\n");
1da177e4 LT	465	return -ENODEV;
	466	}
	467
c667aac8 MS	468	/*
	469	* Register with IUCV and connect to *MONITOR service
	470	*/
	471	rc = iucv_register(&monreader_iucv_handler, 1);
	472	if (rc) {
a4f5a299 GS	473	pr_err("The z/VM *MONITOR record device driver failed to "
a4f5a299 GS	474	"register with IUCV\n");
c667aac8 MS	475	return rc;
c667aac8 MS	476	}
c667aac8	477
1da177e4 LT	478	rc = segment_type(mon_dcss_name);
1da177e4 LT	479	if (rc < 0) {
ca68305b	480	segment_warning(rc, mon_dcss_name);
c667aac8	481	goto out_iucv;
1da177e4 LT	482	}
1da177e4 LT	483	if (rc != SEG_TYPE_SC) {
a4f5a299 GS	484	pr_err("The specified *MONITOR DCSS %s does not have the "
a4f5a299 GS	485	"required type SC\n", mon_dcss_name);
c667aac8 MS	486	rc = -EINVAL;
c667aac8 MS	487	goto out_iucv;
1da177e4 LT	488	}
	489
	490	rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
	491	&mon_dcss_start, &mon_dcss_end);
	492	if (rc < 0) {
ca68305b	493	segment_warning(rc, mon_dcss_name);
c667aac8 MS	494	rc = -EINVAL;
c667aac8 MS	495	goto out_iucv;
1da177e4 LT	496	}
	497	dcss_mkname(mon_dcss_name, &user_data_connect[8]);
	498
	499	rc = misc_register(&mon_dev);
2ca5b6e2	500	if (rc < 0 )
1da177e4	501	goto out;
1da177e4 LT	502	return 0;
	503
	504	out:
	505	segment_unload(mon_dcss_name);
c667aac8 MS	506	out_iucv:
c667aac8 MS	507	iucv_unregister(&monreader_iucv_handler, 1);
1da177e4 LT	508	return rc;
	509	}
	510
c667aac8	511	static void __exit mon_exit(void)
1da177e4 LT	512	{
	513	segment_unload(mon_dcss_name);
	514	WARN_ON(misc_deregister(&mon_dev) != 0);
c667aac8	515	iucv_unregister(&monreader_iucv_handler, 1);
1da177e4 LT	516	return;
	517	}
	518
	519
	520	module_init(mon_init);
	521	module_exit(mon_exit);
	522
	523	module_param_string(mondcss, mon_dcss_name, 9, 0444);
	524	MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
	525	"service, max. 8 chars. Default is MONDCSS");
	526
	527	MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
	528	MODULE_DESCRIPTION("Character device driver for reading z/VM "
	529	"monitor service records.");
	530	MODULE_LICENSE("GPL");