[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>
 */

#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_DEBUG			/* Debug messages on/off */

#define MON_NAME "monreader"

#define P_INFO(x...)	printk(KERN_INFO MON_NAME " info: " x)
#define P_ERROR(x...)	printk(KERN_ERR MON_NAME " error: " x)
#define P_WARNING(x...)	printk(KERN_WARNING MON_NAME " warning: " x)

#ifdef MON_DEBUG
#define P_DEBUG(x...)   printk(KERN_DEBUG MON_NAME " debug: " x)
#else
#define P_DEBUG(x...)   do {} while (0)
#endif

#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) {
		P_ERROR("read, IUCV reply failed with rc = %i\n\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;

	P_ERROR("IUCV connection severed with rc = 0x%X\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) {
		P_WARNING("IUCV message pending, message limit (%i) reached\n",
			  MON_MSGLIM);
		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) {
		P_ERROR("iucv connection to *MONITOR failed with "
			"IPUSER SEVER code = %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)
		P_ERROR("close, iucv_sever 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) {
		P_ERROR("not running under z/VM, driver not loaded\n");
		return -ENODEV;
	}

	/*
	 * Register with IUCV and connect to *MONITOR service
	 */
	rc = iucv_register(&monreader_iucv_handler, 1);
	if (rc) {
		P_ERROR("failed to register with iucv driver\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) {
		P_ERROR("segment %s has unsupported type, should be 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	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/moduleparam.h>
	12	#include <linux/init.h>
6ce46a43	13	#include <linux/smp_lock.h>
1da177e4 LT	14	#include <linux/errno.h>
	15	#include <linux/types.h>
	16	#include <linux/kernel.h>
	17	#include <linux/miscdevice.h>
	18	#include <linux/ctype.h>
	19	#include <linux/spinlock.h>
	20	#include <linux/interrupt.h>
2ca5b6e2 GS	21	#include <linux/poll.h>
2ca5b6e2 GS	22	#include <net/iucv/iucv.h>
1da177e4 LT	23	#include <asm/uaccess.h>
	24	#include <asm/ebcdic.h>
	25	#include <asm/extmem.h>
1da177e4 LT	26
	27	//#define MON_DEBUG /* Debug messages on/off */
	28
	29	#define MON_NAME "monreader"
	30
	31	#define P_INFO(x...) printk(KERN_INFO MON_NAME " info: " x)
	32	#define P_ERROR(x...) printk(KERN_ERR MON_NAME " error: " x)
	33	#define P_WARNING(x...) printk(KERN_WARNING MON_NAME " warning: " x)
	34
	35	#ifdef MON_DEBUG
	36	#define P_DEBUG(x...) printk(KERN_DEBUG MON_NAME " debug: " x)
	37	#else
	38	#define P_DEBUG(x...) do {} while (0)
	39	#endif
	40
	41	#define MON_COLLECT_SAMPLE 0x80
	42	#define MON_COLLECT_EVENT 0x40
	43	#define MON_SERVICE "*MONITOR"
	44	#define MON_IN_USE 0x01
	45	#define MON_MSGLIM 255
	46
	47	static char mon_dcss_name[9] = "MONDCSS\0";
	48
	49	struct mon_msg {
	50	u32 pos;
	51	u32 mca_offset;
c667aac8	52	struct iucv_message msg;
1da177e4 LT	53	char msglim_reached;
	54	char replied_msglim;
	55	};
	56
	57	struct mon_private {
c667aac8	58	struct iucv_path *path;
1da177e4 LT	59	struct mon_msg *msg_array[MON_MSGLIM];
	60	unsigned int write_index;
	61	unsigned int read_index;
	62	atomic_t msglim_count;
	63	atomic_t read_ready;
	64	atomic_t iucv_connected;
	65	atomic_t iucv_severed;
	66	};
	67
	68	static unsigned long mon_in_use = 0;
	69
	70	static unsigned long mon_dcss_start;
	71	static unsigned long mon_dcss_end;
	72
	73	static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
	74	static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
	75
1da177e4 LT	76	static u8 user_data_connect[16] = {
	77	/* Version code, must be 0x01 for shared mode */
	78	0x01,
	79	/* what to collect */
	80	MON_COLLECT_SAMPLE \| MON_COLLECT_EVENT,
	81	/* DCSS name in EBCDIC, 8 bytes padded with blanks */
	82	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	83	0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	84	};
	85
	86	static u8 user_data_sever[16] = {
	87	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	88	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	89	};
	90
	91
	92	/******************************************************************************
	93	* helper functions *
	94	*****************************************************************************/
	95	/*
	96	* Create the 8 bytes EBCDIC DCSS segment name from
	97	* an ASCII name, incl. padding
	98	*/
9b0c455a	99	static void dcss_mkname(char ascii_name, char ebcdic_name)
1da177e4 LT	100	{
	101	int i;
	102
	103	for (i = 0; i < 8; i++) {
	104	if (ascii_name[i] == '\0')
	105	break;
	106	ebcdic_name[i] = toupper(ascii_name[i]);
	107	};
	108	for (; i < 8; i++)
	109	ebcdic_name[i] = ' ';
	110	ASCEBC(ebcdic_name, 8);
	111	}
	112
c667aac8	113	static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
1da177e4	114	{
c667aac8	115	return (u32 ) &monmsg->msg.rmmsg;
1da177e4 LT	116	}
1da177e4 LT	117
c667aac8	118	static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
1da177e4	119	{
c667aac8	120	return (u32 ) &monmsg->msg.rmmsg[4];
1da177e4 LT	121	}
1da177e4 LT	122
c667aac8	123	static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
1da177e4 LT	124	{
	125	return ((u8 ) mon_mca_start(monmsg) + monmsg->mca_offset + index);
	126	}
	127
c667aac8	128	static inline u32 mon_mca_size(struct mon_msg *monmsg)
1da177e4 LT	129	{
	130	return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
	131	}
	132
c667aac8	133	static inline u32 mon_rec_start(struct mon_msg *monmsg)
1da177e4 LT	134	{
	135	return ((u32 ) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
	136	}
	137
c667aac8	138	static inline u32 mon_rec_end(struct mon_msg *monmsg)
1da177e4 LT	139	{
	140	return ((u32 ) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
	141	}
	142
9b0c455a	143	static int mon_check_mca(struct mon_msg *monmsg)
1da177e4 LT	144	{
	145	if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) \|\|
	146	(mon_rec_start(monmsg) < mon_dcss_start) \|\|
	147	(mon_rec_end(monmsg) > mon_dcss_end) \|\|
	148	(mon_mca_type(monmsg, 0) == 0) \|\|
	149	(mon_mca_size(monmsg) % 12 != 0) \|\|
	150	(mon_mca_end(monmsg) <= mon_mca_start(monmsg)) \|\|
	151	(mon_mca_end(monmsg) > mon_dcss_end) \|\|
	152	(mon_mca_start(monmsg) < mon_dcss_start) \|\|
	153	((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
1da177e4	154	return -EINVAL;
1da177e4 LT	155	return 0;
	156	}
	157
9b0c455a MS	158	static int mon_send_reply(struct mon_msg *monmsg,
9b0c455a MS	159	struct mon_private *monpriv)
1da177e4	160	{
1da177e4 LT	161	int rc;
1da177e4 LT	162
c667aac8 MS	163	rc = iucv_message_reply(monpriv->path, &monmsg->msg,
c667aac8 MS	164	IUCV_IPRMDATA, NULL, 0);
1da177e4 LT	165	atomic_dec(&monpriv->msglim_count);
	166	if (likely(!monmsg->msglim_reached)) {
	167	monmsg->pos = 0;
	168	monmsg->mca_offset = 0;
	169	monpriv->read_index = (monpriv->read_index + 1) %
	170	MON_MSGLIM;
	171	atomic_dec(&monpriv->read_ready);
	172	} else
	173	monmsg->replied_msglim = 1;
	174	if (rc) {
	175	P_ERROR("read, IUCV reply failed with rc = %i\n\n", rc);
	176	return -EIO;
	177	}
	178	return 0;
	179	}
	180
9b0c455a	181	static void mon_free_mem(struct mon_private *monpriv)
c667aac8 MS	182	{
	183	int i;
	184
	185	for (i = 0; i < MON_MSGLIM; i++)
	186	if (monpriv->msg_array[i])
	187	kfree(monpriv->msg_array[i]);
	188	kfree(monpriv);
	189	}
	190
9b0c455a	191	static struct mon_private *mon_alloc_mem(void)
1da177e4	192	{
c667aac8	193	int i;
1da177e4 LT	194	struct mon_private *monpriv;
1da177e4 LT	195
88abaab4	196	monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
2ca5b6e2	197	if (!monpriv)
1da177e4	198	return NULL;
1da177e4	199	for (i = 0; i < MON_MSGLIM; i++) {
88abaab4	200	monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
1da177e4 LT	201	GFP_KERNEL);
1da177e4 LT	202	if (!monpriv->msg_array[i]) {
c667aac8	203	mon_free_mem(monpriv);
1da177e4 LT	204	return NULL;
1da177e4 LT	205	}
1da177e4 LT	206	}
	207	return monpriv;
	208	}
	209
c667aac8	210	static inline void mon_next_mca(struct mon_msg *monmsg)
1da177e4 LT	211	{
	212	if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
	213	return;
1da177e4 LT	214	monmsg->mca_offset += 12;
	215	monmsg->pos = 0;
	216	}
	217
9b0c455a	218	static struct mon_msg mon_next_message(struct mon_private monpriv)
1da177e4 LT	219	{
	220	struct mon_msg *monmsg;
	221
	222	if (!atomic_read(&monpriv->read_ready))
	223	return NULL;
	224	monmsg = monpriv->msg_array[monpriv->read_index];
	225	if (unlikely(monmsg->replied_msglim)) {
	226	monmsg->replied_msglim = 0;
	227	monmsg->msglim_reached = 0;
	228	monmsg->pos = 0;
	229	monmsg->mca_offset = 0;
1da177e4 LT	230	monpriv->read_index = (monpriv->read_index + 1) %
	231	MON_MSGLIM;
	232	atomic_dec(&monpriv->read_ready);
	233	return ERR_PTR(-EOVERFLOW);
	234	}
	235	return monmsg;
	236	}
	237
	238
	239	/******************************************************************************
	240	* IUCV handler *
	241	*****************************************************************************/
c667aac8	242	static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
1da177e4	243	{
c667aac8	244	struct mon_private *monpriv = path->private;
1da177e4	245
1da177e4 LT	246	atomic_set(&monpriv->iucv_connected, 1);
	247	wake_up(&mon_conn_wait_queue);
	248	}
	249
c667aac8	250	static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
1da177e4	251	{
c667aac8	252	struct mon_private *monpriv = path->private;
1da177e4	253
c667aac8 MS	254	P_ERROR("IUCV connection severed with rc = 0x%X\n", ipuser[0]);
c667aac8 MS	255	iucv_path_sever(path, NULL);
1da177e4 LT	256	atomic_set(&monpriv->iucv_severed, 1);
	257	wake_up(&mon_conn_wait_queue);
	258	wake_up_interruptible(&mon_read_wait_queue);
	259	}
	260
c667aac8 MS	261	static void mon_iucv_message_pending(struct iucv_path *path,
c667aac8 MS	262	struct iucv_message *msg)
1da177e4	263	{
c667aac8	264	struct mon_private *monpriv = path->private;
1da177e4	265
c667aac8 MS	266	memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
c667aac8 MS	267	msg, sizeof(*msg));
1da177e4 LT	268	if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
	269	P_WARNING("IUCV message pending, message limit (%i) reached\n",
	270	MON_MSGLIM);
	271	monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
	272	}
	273	monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
	274	atomic_inc(&monpriv->read_ready);
	275	wake_up_interruptible(&mon_read_wait_queue);
	276	}
	277
c667aac8 MS	278	static struct iucv_handler monreader_iucv_handler = {
	279	.path_complete = mon_iucv_path_complete,
	280	.path_severed = mon_iucv_path_severed,
	281	.message_pending = mon_iucv_message_pending,
1da177e4 LT	282	};
	283
	284	/******************************************************************************
	285	* file operations *
	286	*****************************************************************************/
c667aac8	287	static int mon_open(struct inode inode, struct file filp)
1da177e4	288	{
1da177e4	289	struct mon_private *monpriv;
c667aac8	290	int rc;
1da177e4 LT	291
	292	/*
	293	* only one user allowed
	294	*/
6ce46a43	295	lock_kernel();
c667aac8	296	rc = -EBUSY;
1da177e4	297	if (test_and_set_bit(MON_IN_USE, &mon_in_use))
c667aac8	298	goto out;
1da177e4	299
c667aac8	300	rc = -ENOMEM;
1da177e4 LT	301	monpriv = mon_alloc_mem();
1da177e4 LT	302	if (!monpriv)
c667aac8	303	goto out_use;
1da177e4 LT	304
1da177e4 LT	305	/*
c667aac8	306	* Connect to *MONITOR service
1da177e4	307	*/
c667aac8 MS	308	monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
	309	if (!monpriv->path)
	310	goto out_priv;
	311	rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
	312	MON_SERVICE, NULL, user_data_connect, monpriv);
1da177e4 LT	313	if (rc) {
	314	P_ERROR("iucv connection to *MONITOR failed with "
	315	"IPUSER SEVER code = %i\n", rc);
	316	rc = -EIO;
c667aac8	317	goto out_path;
1da177e4 LT	318	}
	319	/*
	320	* Wait for connection confirmation
	321	*/
	322	wait_event(mon_conn_wait_queue,
	323	atomic_read(&monpriv->iucv_connected) \|\|
	324	atomic_read(&monpriv->iucv_severed));
	325	if (atomic_read(&monpriv->iucv_severed)) {
	326	atomic_set(&monpriv->iucv_severed, 0);
	327	atomic_set(&monpriv->iucv_connected, 0);
	328	rc = -EIO;
c667aac8	329	goto out_path;
1da177e4	330	}
1da177e4	331	filp->private_data = monpriv;
6ce46a43	332	unlock_kernel();
1da177e4 LT	333	return nonseekable_open(inode, filp);
1da177e4 LT	334
c667aac8 MS	335	out_path:
	336	kfree(monpriv->path);
	337	out_priv:
	338	mon_free_mem(monpriv);
	339	out_use:
1da177e4	340	clear_bit(MON_IN_USE, &mon_in_use);
c667aac8	341	out:
6ce46a43	342	unlock_kernel();
1da177e4 LT	343	return rc;
	344	}
	345
c667aac8	346	static int mon_close(struct inode inode, struct file filp)
1da177e4 LT	347	{
	348	int rc, i;
	349	struct mon_private *monpriv = filp->private_data;
	350
	351	/*
	352	* Close IUCV connection and unregister
	353	*/
c667aac8	354	rc = iucv_path_sever(monpriv->path, user_data_sever);
1da177e4 LT	355	if (rc)
1da177e4 LT	356	P_ERROR("close, iucv_sever failed with rc = %i\n", rc);
1da177e4	357
1da177e4 LT	358	atomic_set(&monpriv->iucv_severed, 0);
	359	atomic_set(&monpriv->iucv_connected, 0);
	360	atomic_set(&monpriv->read_ready, 0);
	361	atomic_set(&monpriv->msglim_count, 0);
	362	monpriv->write_index = 0;
	363	monpriv->read_index = 0;
	364
	365	for (i = 0; i < MON_MSGLIM; i++)
	366	kfree(monpriv->msg_array[i]);
	367	kfree(monpriv);
	368	clear_bit(MON_IN_USE, &mon_in_use);
	369	return 0;
	370	}
	371
c667aac8 MS	372	static ssize_t mon_read(struct file filp, char __user data,
c667aac8 MS	373	size_t count, loff_t *ppos)
1da177e4 LT	374	{
	375	struct mon_private *monpriv = filp->private_data;
	376	struct mon_msg *monmsg;
	377	int ret;
	378	u32 mce_start;
	379
	380	monmsg = mon_next_message(monpriv);
	381	if (IS_ERR(monmsg))
	382	return PTR_ERR(monmsg);
	383
	384	if (!monmsg) {
	385	if (filp->f_flags & O_NONBLOCK)
	386	return -EAGAIN;
	387	ret = wait_event_interruptible(mon_read_wait_queue,
	388	atomic_read(&monpriv->read_ready) \|\|
	389	atomic_read(&monpriv->iucv_severed));
	390	if (ret)
	391	return ret;
	392	if (unlikely(atomic_read(&monpriv->iucv_severed)))
	393	return -EIO;
	394	monmsg = monpriv->msg_array[monpriv->read_index];
	395	}
	396
2ca5b6e2	397	if (!monmsg->pos)
1da177e4	398	monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
1da177e4 LT	399	if (mon_check_mca(monmsg))
	400	goto reply;
	401
	402	/* read monitor control element (12 bytes) first */
	403	mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
	404	if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
	405	count = min(count, (size_t) mce_start + 12 - monmsg->pos);
	406	ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
	407	count);
	408	if (ret)
	409	return -EFAULT;
	410	monmsg->pos += count;
	411	if (monmsg->pos == mce_start + 12)
	412	monmsg->pos = mon_rec_start(monmsg);
	413	goto out_copy;
	414	}
	415
	416	/* read records */
	417	if (monmsg->pos <= mon_rec_end(monmsg)) {
	418	count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
	419	+ 1);
	420	ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
	421	count);
	422	if (ret)
	423	return -EFAULT;
	424	monmsg->pos += count;
	425	if (monmsg->pos > mon_rec_end(monmsg))
	426	mon_next_mca(monmsg);
	427	goto out_copy;
	428	}
	429	reply:
	430	ret = mon_send_reply(monmsg, monpriv);
	431	return ret;
	432
	433	out_copy:
	434	*ppos += count;
	435	return count;
	436	}
	437
c667aac8	438	static unsigned int mon_poll(struct file filp, struct poll_table_struct p)
1da177e4 LT	439	{
	440	struct mon_private *monpriv = filp->private_data;
	441
	442	poll_wait(filp, &mon_read_wait_queue, p);
	443	if (unlikely(atomic_read(&monpriv->iucv_severed)))
	444	return POLLERR;
	445	if (atomic_read(&monpriv->read_ready))
	446	return POLLIN \| POLLRDNORM;
	447	return 0;
	448	}
	449
d54b1fdb	450	static const struct file_operations mon_fops = {
1da177e4 LT	451	.owner = THIS_MODULE,
	452	.open = &mon_open,
	453	.release = &mon_close,
	454	.read = &mon_read,
	455	.poll = &mon_poll,
	456	};
	457
	458	static struct miscdevice mon_dev = {
	459	.name = "monreader",
1da177e4 LT	460	.fops = &mon_fops,
	461	.minor = MISC_DYNAMIC_MINOR,
	462	};
	463
	464	/******************************************************************************
	465	* module init/exit *
	466	*****************************************************************************/
c667aac8	467	static int __init mon_init(void)
1da177e4 LT	468	{
	469	int rc;
	470
	471	if (!MACHINE_IS_VM) {
	472	P_ERROR("not running under z/VM, driver not loaded\n");
	473	return -ENODEV;
	474	}
	475
c667aac8 MS	476	/*
	477	* Register with IUCV and connect to *MONITOR service
	478	*/
	479	rc = iucv_register(&monreader_iucv_handler, 1);
	480	if (rc) {
	481	P_ERROR("failed to register with iucv driver\n");
	482	return rc;
	483	}
c667aac8	484
1da177e4 LT	485	rc = segment_type(mon_dcss_name);
1da177e4 LT	486	if (rc < 0) {
ca68305b	487	segment_warning(rc, mon_dcss_name);
c667aac8	488	goto out_iucv;
1da177e4 LT	489	}
	490	if (rc != SEG_TYPE_SC) {
	491	P_ERROR("segment %s has unsupported type, should be SC\n",
	492	mon_dcss_name);
c667aac8 MS	493	rc = -EINVAL;
c667aac8 MS	494	goto out_iucv;
1da177e4 LT	495	}
	496
	497	rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
	498	&mon_dcss_start, &mon_dcss_end);
	499	if (rc < 0) {
ca68305b	500	segment_warning(rc, mon_dcss_name);
c667aac8 MS	501	rc = -EINVAL;
c667aac8 MS	502	goto out_iucv;
1da177e4 LT	503	}
	504	dcss_mkname(mon_dcss_name, &user_data_connect[8]);
	505
	506	rc = misc_register(&mon_dev);
2ca5b6e2	507	if (rc < 0 )
1da177e4	508	goto out;
1da177e4 LT	509	return 0;
	510
	511	out:
	512	segment_unload(mon_dcss_name);
c667aac8 MS	513	out_iucv:
c667aac8 MS	514	iucv_unregister(&monreader_iucv_handler, 1);
1da177e4 LT	515	return rc;
	516	}
	517
c667aac8	518	static void __exit mon_exit(void)
1da177e4 LT	519	{
	520	segment_unload(mon_dcss_name);
	521	WARN_ON(misc_deregister(&mon_dev) != 0);
c667aac8	522	iucv_unregister(&monreader_iucv_handler, 1);
1da177e4 LT	523	return;
	524	}
	525
	526
	527	module_init(mon_init);
	528	module_exit(mon_exit);
	529
	530	module_param_string(mondcss, mon_dcss_name, 9, 0444);
	531	MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
	532	"service, max. 8 chars. Default is MONDCSS");
	533
	534	MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
	535	MODULE_DESCRIPTION("Character device driver for reading z/VM "
	536	"monitor service records.");
	537	MODULE_LICENSE("GPL");