[mirror_ubuntu-zesty-kernel.git] / drivers / s390 / char / monreader.c

/*
 * Character device driver for reading z/VM *MONITOR service records.
 *
 * Copyright IBM Corp. 2004, 2009
 *
 * 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/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 <linux/device.h>
#include <linux/slab.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,
};

static struct device *monreader_device;

/******************************************************************************
 *                             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
	 */
	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;
	dev_set_drvdata(monreader_device, monpriv);
	return nonseekable_open(inode, filp);

out_path:
	iucv_path_free(monpriv->path);
out_priv:
	mon_free_mem(monpriv);
out_use:
	clear_bit(MON_IN_USE, &mon_in_use);
out:
	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
	 */
	if (monpriv->path) {
		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);
		iucv_path_free(monpriv->path);
	}

	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;
	dev_set_drvdata(monreader_device, NULL);

	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,
};


/******************************************************************************
 *				suspend / resume			      *
 *****************************************************************************/
static int monreader_freeze(struct device *dev)
{
	struct mon_private *monpriv = dev_get_drvdata(dev);
	int rc;

	if (!monpriv)
		return 0;
	if (monpriv->path) {
		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);
		iucv_path_free(monpriv->path);
	}
	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;
	monpriv->path = NULL;
	return 0;
}

static int monreader_thaw(struct device *dev)
{
	struct mon_private *monpriv = dev_get_drvdata(dev);
	int rc;

	if (!monpriv)
		return 0;
	rc = -ENOMEM;
	monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
	if (!monpriv->path)
		goto out;
	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);
		goto out_path;
	}
	wait_event(mon_conn_wait_queue,
		   atomic_read(&monpriv->iucv_connected) ||
		   atomic_read(&monpriv->iucv_severed));
	if (atomic_read(&monpriv->iucv_severed))
		goto out_path;
	return 0;
out_path:
	rc = -EIO;
	iucv_path_free(monpriv->path);
	monpriv->path = NULL;
out:
	atomic_set(&monpriv->iucv_severed, 1);
	return rc;
}

static int monreader_restore(struct device *dev)
{
	int rc;

	segment_unload(mon_dcss_name);
	rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
			  &mon_dcss_start, &mon_dcss_end);
	if (rc < 0) {
		segment_warning(rc, mon_dcss_name);
		panic("fatal monreader resume error: no monitor dcss\n");
	}
	return monreader_thaw(dev);
}

static const struct dev_pm_ops monreader_pm_ops = {
	.freeze  = monreader_freeze,
	.thaw	 = monreader_thaw,
	.restore = monreader_restore,
};

static struct device_driver monreader_driver = {
	.name = "monreader",
	.bus  = &iucv_bus,
	.pm   = &monreader_pm_ops,
};


/******************************************************************************
 *                              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 = driver_register(&monreader_driver);
	if (rc)
		goto out_iucv;
	monreader_device = kzalloc(sizeof(struct device), GFP_KERNEL);
	if (!monreader_device)
		goto out_driver;
	dev_set_name(monreader_device, "monreader-dev");
	monreader_device->bus = &iucv_bus;
	monreader_device->parent = iucv_root;
	monreader_device->driver = &monreader_driver;
	monreader_device->release = (void (*)(struct device *))kfree;
	rc = device_register(monreader_device);
	if (rc) {
		put_device(monreader_device);
		goto out_driver;
	}

	rc = segment_type(mon_dcss_name);
	if (rc < 0) {
		segment_warning(rc, mon_dcss_name);
		goto out_device;
	}
	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_device;
	}

	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_device;
	}
	dcss_mkname(mon_dcss_name, &user_data_connect[8]);

	/*
	 * misc_register() has to be the last action in module_init(), because
	 * file operations will be available right after this.
	 */
	rc = misc_register(&mon_dev);
	if (rc < 0 )
		goto out;
	return 0;

out:
	segment_unload(mon_dcss_name);
out_device:
	device_unregister(monreader_device);
out_driver:
	driver_unregister(&monreader_driver);
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);
	device_unregister(monreader_device);
	driver_unregister(&monreader_driver);
	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	1	/*
1da177e4 LT	2	* Character device driver for reading z/VM *MONITOR service records.
1da177e4 LT	3	*
2b1e3e55 GS	4	* Copyright IBM Corp. 2004, 2009
	5	*
	6	* Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
1da177e4 LT	7	*/
1da177e4 LT	8
a4f5a299 GS	9	#define KMSG_COMPONENT "monreader"
	10	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
	11
1da177e4 LT	12	#include <linux/module.h>
	13	#include <linux/moduleparam.h>
	14	#include <linux/init.h>
	15	#include <linux/errno.h>
	16	#include <linux/types.h>
	17	#include <linux/kernel.h>
	18	#include <linux/miscdevice.h>
	19	#include <linux/ctype.h>
	20	#include <linux/spinlock.h>
	21	#include <linux/interrupt.h>
2ca5b6e2	22	#include <linux/poll.h>
2b1e3e55	23	#include <linux/device.h>
5a0e3ad6	24	#include <linux/slab.h>
2ca5b6e2	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
2b1e3e55	81	static struct device *monreader_device;
1da177e4 LT	82
	83	/******************************************************************************
	84	* helper functions *
	85	*****************************************************************************/
	86	/*
	87	* Create the 8 bytes EBCDIC DCSS segment name from
	88	* an ASCII name, incl. padding
	89	*/
9b0c455a	90	static void dcss_mkname(char ascii_name, char ebcdic_name)
1da177e4 LT	91	{
	92	int i;
	93
	94	for (i = 0; i < 8; i++) {
	95	if (ascii_name[i] == '\0')
	96	break;
	97	ebcdic_name[i] = toupper(ascii_name[i]);
	98	};
	99	for (; i < 8; i++)
	100	ebcdic_name[i] = ' ';
	101	ASCEBC(ebcdic_name, 8);
	102	}
	103
c667aac8	104	static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
1da177e4	105	{
c667aac8	106	return (u32 ) &monmsg->msg.rmmsg;
1da177e4 LT	107	}
1da177e4 LT	108
c667aac8	109	static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
1da177e4	110	{
c667aac8	111	return (u32 ) &monmsg->msg.rmmsg[4];
1da177e4 LT	112	}
1da177e4 LT	113
c667aac8	114	static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
1da177e4 LT	115	{
	116	return ((u8 ) mon_mca_start(monmsg) + monmsg->mca_offset + index);
	117	}
	118
c667aac8	119	static inline u32 mon_mca_size(struct mon_msg *monmsg)
1da177e4 LT	120	{
	121	return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
	122	}
	123
c667aac8	124	static inline u32 mon_rec_start(struct mon_msg *monmsg)
1da177e4 LT	125	{
	126	return ((u32 ) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
	127	}
	128
c667aac8	129	static inline u32 mon_rec_end(struct mon_msg *monmsg)
1da177e4 LT	130	{
	131	return ((u32 ) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
	132	}
	133
9b0c455a	134	static int mon_check_mca(struct mon_msg *monmsg)
1da177e4 LT	135	{
	136	if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) \|\|
	137	(mon_rec_start(monmsg) < mon_dcss_start) \|\|
	138	(mon_rec_end(monmsg) > mon_dcss_end) \|\|
	139	(mon_mca_type(monmsg, 0) == 0) \|\|
	140	(mon_mca_size(monmsg) % 12 != 0) \|\|
	141	(mon_mca_end(monmsg) <= mon_mca_start(monmsg)) \|\|
	142	(mon_mca_end(monmsg) > mon_dcss_end) \|\|
	143	(mon_mca_start(monmsg) < mon_dcss_start) \|\|
	144	((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
1da177e4	145	return -EINVAL;
1da177e4 LT	146	return 0;
	147	}
	148
9b0c455a MS	149	static int mon_send_reply(struct mon_msg *monmsg,
9b0c455a MS	150	struct mon_private *monpriv)
1da177e4	151	{
1da177e4 LT	152	int rc;
1da177e4 LT	153
c667aac8 MS	154	rc = iucv_message_reply(monpriv->path, &monmsg->msg,
c667aac8 MS	155	IUCV_IPRMDATA, NULL, 0);
1da177e4 LT	156	atomic_dec(&monpriv->msglim_count);
	157	if (likely(!monmsg->msglim_reached)) {
	158	monmsg->pos = 0;
	159	monmsg->mca_offset = 0;
	160	monpriv->read_index = (monpriv->read_index + 1) %
	161	MON_MSGLIM;
	162	atomic_dec(&monpriv->read_ready);
	163	} else
	164	monmsg->replied_msglim = 1;
	165	if (rc) {
a4f5a299	166	pr_err("Reading monitor data failed with rc=%i\n", rc);
1da177e4 LT	167	return -EIO;
	168	}
	169	return 0;
	170	}
	171
9b0c455a	172	static void mon_free_mem(struct mon_private *monpriv)
c667aac8 MS	173	{
	174	int i;
	175
	176	for (i = 0; i < MON_MSGLIM; i++)
	177	if (monpriv->msg_array[i])
	178	kfree(monpriv->msg_array[i]);
	179	kfree(monpriv);
	180	}
	181
9b0c455a	182	static struct mon_private *mon_alloc_mem(void)
1da177e4	183	{
c667aac8	184	int i;
1da177e4 LT	185	struct mon_private *monpriv;
1da177e4 LT	186
88abaab4	187	monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
2ca5b6e2	188	if (!monpriv)
1da177e4	189	return NULL;
1da177e4	190	for (i = 0; i < MON_MSGLIM; i++) {
88abaab4	191	monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
1da177e4 LT	192	GFP_KERNEL);
1da177e4 LT	193	if (!monpriv->msg_array[i]) {
c667aac8	194	mon_free_mem(monpriv);
1da177e4 LT	195	return NULL;
1da177e4 LT	196	}
1da177e4 LT	197	}
	198	return monpriv;
	199	}
	200
c667aac8	201	static inline void mon_next_mca(struct mon_msg *monmsg)
1da177e4 LT	202	{
	203	if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
	204	return;
1da177e4 LT	205	monmsg->mca_offset += 12;
	206	monmsg->pos = 0;
	207	}
	208
9b0c455a	209	static struct mon_msg mon_next_message(struct mon_private monpriv)
1da177e4 LT	210	{
	211	struct mon_msg *monmsg;
	212
	213	if (!atomic_read(&monpriv->read_ready))
	214	return NULL;
	215	monmsg = monpriv->msg_array[monpriv->read_index];
	216	if (unlikely(monmsg->replied_msglim)) {
	217	monmsg->replied_msglim = 0;
	218	monmsg->msglim_reached = 0;
	219	monmsg->pos = 0;
	220	monmsg->mca_offset = 0;
1da177e4 LT	221	monpriv->read_index = (monpriv->read_index + 1) %
	222	MON_MSGLIM;
	223	atomic_dec(&monpriv->read_ready);
	224	return ERR_PTR(-EOVERFLOW);
	225	}
	226	return monmsg;
	227	}
	228
	229
	230	/******************************************************************************
	231	* IUCV handler *
	232	*****************************************************************************/
c667aac8	233	static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
1da177e4	234	{
c667aac8	235	struct mon_private *monpriv = path->private;
1da177e4	236
1da177e4 LT	237	atomic_set(&monpriv->iucv_connected, 1);
	238	wake_up(&mon_conn_wait_queue);
	239	}
	240
c667aac8	241	static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
1da177e4	242	{
c667aac8	243	struct mon_private *monpriv = path->private;
1da177e4	244
a4f5a299 GS	245	pr_err("z/VM *MONITOR system service disconnected with rc=%i\n",
a4f5a299 GS	246	ipuser[0]);
c667aac8	247	iucv_path_sever(path, NULL);
1da177e4 LT	248	atomic_set(&monpriv->iucv_severed, 1);
	249	wake_up(&mon_conn_wait_queue);
	250	wake_up_interruptible(&mon_read_wait_queue);
	251	}
	252
c667aac8 MS	253	static void mon_iucv_message_pending(struct iucv_path *path,
c667aac8 MS	254	struct iucv_message *msg)
1da177e4	255	{
c667aac8	256	struct mon_private *monpriv = path->private;
1da177e4	257
c667aac8 MS	258	memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
c667aac8 MS	259	msg, sizeof(*msg));
1da177e4	260	if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
a4f5a299	261	pr_warning("The read queue for monitor data is full\n");
1da177e4 LT	262	monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
	263	}
	264	monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
	265	atomic_inc(&monpriv->read_ready);
	266	wake_up_interruptible(&mon_read_wait_queue);
	267	}
	268
c667aac8 MS	269	static struct iucv_handler monreader_iucv_handler = {
	270	.path_complete = mon_iucv_path_complete,
	271	.path_severed = mon_iucv_path_severed,
	272	.message_pending = mon_iucv_message_pending,
1da177e4 LT	273	};
	274
	275	/******************************************************************************
	276	* file operations *
	277	*****************************************************************************/
c667aac8	278	static int mon_open(struct inode inode, struct file filp)
1da177e4	279	{
1da177e4	280	struct mon_private *monpriv;
c667aac8	281	int rc;
1da177e4 LT	282
	283	/*
	284	* only one user allowed
	285	*/
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;
99357742	322	dev_set_drvdata(monreader_device, monpriv);
1da177e4 LT	323	return nonseekable_open(inode, filp);
1da177e4 LT	324
c667aac8	325	out_path:
2b1e3e55	326	iucv_path_free(monpriv->path);
c667aac8 MS	327	out_priv:
	328	mon_free_mem(monpriv);
	329	out_use:
1da177e4	330	clear_bit(MON_IN_USE, &mon_in_use);
c667aac8	331	out:
1da177e4 LT	332	return rc;
	333	}
	334
c667aac8	335	static int mon_close(struct inode inode, struct file filp)
1da177e4 LT	336	{
	337	int rc, i;
	338	struct mon_private *monpriv = filp->private_data;
	339
	340	/*
	341	* Close IUCV connection and unregister
	342	*/
2b1e3e55 GS	343	if (monpriv->path) {
	344	rc = iucv_path_sever(monpriv->path, user_data_sever);
	345	if (rc)
	346	pr_warning("Disconnecting the z/VM *MONITOR system "
	347	"service failed with rc=%i\n", rc);
	348	iucv_path_free(monpriv->path);
	349	}
1da177e4	350
1da177e4 LT	351	atomic_set(&monpriv->iucv_severed, 0);
	352	atomic_set(&monpriv->iucv_connected, 0);
	353	atomic_set(&monpriv->read_ready, 0);
	354	atomic_set(&monpriv->msglim_count, 0);
	355	monpriv->write_index = 0;
	356	monpriv->read_index = 0;
ccaf6553	357	dev_set_drvdata(monreader_device, NULL);
1da177e4 LT	358
	359	for (i = 0; i < MON_MSGLIM; i++)
	360	kfree(monpriv->msg_array[i]);
	361	kfree(monpriv);
	362	clear_bit(MON_IN_USE, &mon_in_use);
	363	return 0;
	364	}
	365
c667aac8 MS	366	static ssize_t mon_read(struct file filp, char __user data,
c667aac8 MS	367	size_t count, loff_t *ppos)
1da177e4 LT	368	{
	369	struct mon_private *monpriv = filp->private_data;
	370	struct mon_msg *monmsg;
	371	int ret;
	372	u32 mce_start;
	373
	374	monmsg = mon_next_message(monpriv);
	375	if (IS_ERR(monmsg))
	376	return PTR_ERR(monmsg);
	377
	378	if (!monmsg) {
	379	if (filp->f_flags & O_NONBLOCK)
	380	return -EAGAIN;
	381	ret = wait_event_interruptible(mon_read_wait_queue,
	382	atomic_read(&monpriv->read_ready) \|\|
	383	atomic_read(&monpriv->iucv_severed));
	384	if (ret)
	385	return ret;
	386	if (unlikely(atomic_read(&monpriv->iucv_severed)))
	387	return -EIO;
	388	monmsg = monpriv->msg_array[monpriv->read_index];
	389	}
	390
2ca5b6e2	391	if (!monmsg->pos)
1da177e4	392	monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
1da177e4 LT	393	if (mon_check_mca(monmsg))
	394	goto reply;
	395
	396	/* read monitor control element (12 bytes) first */
	397	mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
	398	if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
	399	count = min(count, (size_t) mce_start + 12 - monmsg->pos);
	400	ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
	401	count);
	402	if (ret)
	403	return -EFAULT;
	404	monmsg->pos += count;
	405	if (monmsg->pos == mce_start + 12)
	406	monmsg->pos = mon_rec_start(monmsg);
	407	goto out_copy;
	408	}
	409
	410	/* read records */
	411	if (monmsg->pos <= mon_rec_end(monmsg)) {
	412	count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
	413	+ 1);
	414	ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
	415	count);
	416	if (ret)
	417	return -EFAULT;
	418	monmsg->pos += count;
	419	if (monmsg->pos > mon_rec_end(monmsg))
	420	mon_next_mca(monmsg);
	421	goto out_copy;
	422	}
	423	reply:
	424	ret = mon_send_reply(monmsg, monpriv);
	425	return ret;
	426
	427	out_copy:
	428	*ppos += count;
	429	return count;
	430	}
	431
c667aac8	432	static unsigned int mon_poll(struct file filp, struct poll_table_struct p)
1da177e4 LT	433	{
	434	struct mon_private *monpriv = filp->private_data;
	435
	436	poll_wait(filp, &mon_read_wait_queue, p);
	437	if (unlikely(atomic_read(&monpriv->iucv_severed)))
	438	return POLLERR;
	439	if (atomic_read(&monpriv->read_ready))
	440	return POLLIN \| POLLRDNORM;
	441	return 0;
	442	}
	443
d54b1fdb	444	static const struct file_operations mon_fops = {
1da177e4 LT	445	.owner = THIS_MODULE,
	446	.open = &mon_open,
	447	.release = &mon_close,
	448	.read = &mon_read,
	449	.poll = &mon_poll,
	450	};
	451
	452	static struct miscdevice mon_dev = {
	453	.name = "monreader",
1da177e4 LT	454	.fops = &mon_fops,
	455	.minor = MISC_DYNAMIC_MINOR,
	456	};
	457
2b1e3e55 GS	458
	459	/******************************************************************************
	460	* suspend / resume *
	461	*****************************************************************************/
	462	static int monreader_freeze(struct device *dev)
	463	{
99357742	464	struct mon_private *monpriv = dev_get_drvdata(dev);
2b1e3e55 GS	465	int rc;
	466
	467	if (!monpriv)
	468	return 0;
	469	if (monpriv->path) {
	470	rc = iucv_path_sever(monpriv->path, user_data_sever);
	471	if (rc)
	472	pr_warning("Disconnecting the z/VM *MONITOR system "
	473	"service failed with rc=%i\n", rc);
	474	iucv_path_free(monpriv->path);
	475	}
	476	atomic_set(&monpriv->iucv_severed, 0);
	477	atomic_set(&monpriv->iucv_connected, 0);
	478	atomic_set(&monpriv->read_ready, 0);
	479	atomic_set(&monpriv->msglim_count, 0);
	480	monpriv->write_index = 0;
	481	monpriv->read_index = 0;
	482	monpriv->path = NULL;
	483	return 0;
	484	}
	485
	486	static int monreader_thaw(struct device *dev)
	487	{
4f0076f7	488	struct mon_private *monpriv = dev_get_drvdata(dev);
2b1e3e55 GS	489	int rc;
	490
	491	if (!monpriv)
	492	return 0;
	493	rc = -ENOMEM;
	494	monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
	495	if (!monpriv->path)
	496	goto out;
	497	rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
	498	MON_SERVICE, NULL, user_data_connect, monpriv);
	499	if (rc) {
	500	pr_err("Connecting to the z/VM *MONITOR system service "
	501	"failed with rc=%i\n", rc);
	502	goto out_path;
	503	}
	504	wait_event(mon_conn_wait_queue,
	505	atomic_read(&monpriv->iucv_connected) \|\|
	506	atomic_read(&monpriv->iucv_severed));
	507	if (atomic_read(&monpriv->iucv_severed))
	508	goto out_path;
	509	return 0;
	510	out_path:
	511	rc = -EIO;
	512	iucv_path_free(monpriv->path);
	513	monpriv->path = NULL;
	514	out:
	515	atomic_set(&monpriv->iucv_severed, 1);
	516	return rc;
	517	}
	518
	519	static int monreader_restore(struct device *dev)
	520	{
	521	int rc;
	522
	523	segment_unload(mon_dcss_name);
	524	rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
	525	&mon_dcss_start, &mon_dcss_end);
	526	if (rc < 0) {
	527	segment_warning(rc, mon_dcss_name);
	528	panic("fatal monreader resume error: no monitor dcss\n");
	529	}
	530	return monreader_thaw(dev);
	531	}
	532
47145210	533	static const struct dev_pm_ops monreader_pm_ops = {
2b1e3e55 GS	534	.freeze = monreader_freeze,
	535	.thaw = monreader_thaw,
	536	.restore = monreader_restore,
	537	};
	538
	539	static struct device_driver monreader_driver = {
	540	.name = "monreader",
	541	.bus = &iucv_bus,
	542	.pm = &monreader_pm_ops,
	543	};
	544
	545
1da177e4 LT	546	/******************************************************************************
	547	* module init/exit *
	548	*****************************************************************************/
c667aac8	549	static int __init mon_init(void)
1da177e4 LT	550	{
	551	int rc;
	552
	553	if (!MACHINE_IS_VM) {
a4f5a299 GS	554	pr_err("The z/VM *MONITOR record device driver cannot be "
a4f5a299 GS	555	"loaded without z/VM\n");
1da177e4 LT	556	return -ENODEV;
	557	}
	558
c667aac8 MS	559	/*
	560	* Register with IUCV and connect to *MONITOR service
	561	*/
	562	rc = iucv_register(&monreader_iucv_handler, 1);
	563	if (rc) {
a4f5a299 GS	564	pr_err("The z/VM *MONITOR record device driver failed to "
a4f5a299 GS	565	"register with IUCV\n");
c667aac8 MS	566	return rc;
c667aac8 MS	567	}
c667aac8	568
2b1e3e55 GS	569	rc = driver_register(&monreader_driver);
	570	if (rc)
	571	goto out_iucv;
	572	monreader_device = kzalloc(sizeof(struct device), GFP_KERNEL);
	573	if (!monreader_device)
	574	goto out_driver;
	575	dev_set_name(monreader_device, "monreader-dev");
	576	monreader_device->bus = &iucv_bus;
	577	monreader_device->parent = iucv_root;
	578	monreader_device->driver = &monreader_driver;
	579	monreader_device->release = (void ()(struct device ))kfree;
	580	rc = device_register(monreader_device);
	581	if (rc) {
c6304933	582	put_device(monreader_device);
2b1e3e55 GS	583	goto out_driver;
	584	}
	585
1da177e4 LT	586	rc = segment_type(mon_dcss_name);
1da177e4 LT	587	if (rc < 0) {
ca68305b	588	segment_warning(rc, mon_dcss_name);
2b1e3e55	589	goto out_device;
1da177e4 LT	590	}
1da177e4 LT	591	if (rc != SEG_TYPE_SC) {
a4f5a299 GS	592	pr_err("The specified *MONITOR DCSS %s does not have the "
a4f5a299 GS	593	"required type SC\n", mon_dcss_name);
c667aac8	594	rc = -EINVAL;
2b1e3e55	595	goto out_device;
1da177e4 LT	596	}
	597
	598	rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
	599	&mon_dcss_start, &mon_dcss_end);
	600	if (rc < 0) {
ca68305b	601	segment_warning(rc, mon_dcss_name);
c667aac8	602	rc = -EINVAL;
2b1e3e55	603	goto out_device;
1da177e4 LT	604	}
	605	dcss_mkname(mon_dcss_name, &user_data_connect[8]);
	606
1963403a GS	607	/*
	608	* misc_register() has to be the last action in module_init(), because
	609	* file operations will be available right after this.
	610	*/
1da177e4	611	rc = misc_register(&mon_dev);
2ca5b6e2	612	if (rc < 0 )
1da177e4	613	goto out;
1da177e4 LT	614	return 0;
	615
	616	out:
	617	segment_unload(mon_dcss_name);
2b1e3e55 GS	618	out_device:
	619	device_unregister(monreader_device);
	620	out_driver:
	621	driver_unregister(&monreader_driver);
c667aac8 MS	622	out_iucv:
c667aac8 MS	623	iucv_unregister(&monreader_iucv_handler, 1);
1da177e4 LT	624	return rc;
	625	}
	626
c667aac8	627	static void __exit mon_exit(void)
1da177e4 LT	628	{
	629	segment_unload(mon_dcss_name);
	630	WARN_ON(misc_deregister(&mon_dev) != 0);
2b1e3e55 GS	631	device_unregister(monreader_device);
2b1e3e55 GS	632	driver_unregister(&monreader_driver);
c667aac8	633	iucv_unregister(&monreader_iucv_handler, 1);
1da177e4 LT	634	return;
	635	}
	636
	637
	638	module_init(mon_init);
	639	module_exit(mon_exit);
	640
	641	module_param_string(mondcss, mon_dcss_name, 9, 0444);
	642	MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
	643	"service, max. 8 chars. Default is MONDCSS");
	644
	645	MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
	646	MODULE_DESCRIPTION("Character device driver for reading z/VM "
	647	"monitor service records.");
	648	MODULE_LICENSE("GPL");