[deliverable/linux.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/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 <linux/device.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
	 */
	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;
	monreader_device->driver_data = monpriv;
	unlock_kernel();
	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:
	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
	 */
	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;

	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->driver_data;
	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->driver_data;
	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 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) {
		kfree(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]);

	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
	1	/*
	2	* Character device driver for reading z/VM *MONITOR service records.
	3	*
	4	* Copyright IBM Corp. 2004, 2009
	5	*
	6	* Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
	7	*/
	8
	9	#define KMSG_COMPONENT "monreader"
	10	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
	11
	12	#include <linux/module.h>
	13	#include <linux/moduleparam.h>
	14	#include <linux/init.h>
	15	#include <linux/smp_lock.h>
	16	#include <linux/errno.h>
	17	#include <linux/types.h>
	18	#include <linux/kernel.h>
	19	#include <linux/miscdevice.h>
	20	#include <linux/ctype.h>
	21	#include <linux/spinlock.h>
	22	#include <linux/interrupt.h>
	23	#include <linux/poll.h>
	24	#include <linux/device.h>
	25	#include <net/iucv/iucv.h>
	26	#include <asm/uaccess.h>
	27	#include <asm/ebcdic.h>
	28	#include <asm/extmem.h>
	29
	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;
	42	struct iucv_message msg;
	43	char msglim_reached;
	44	char replied_msglim;
	45	};
	46
	47	struct mon_private {
	48	struct iucv_path *path;
	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
	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	static struct device *monreader_device;
	82
	83	/******************************************************************************
	84	* helper functions *
	85	*****************************************************************************/
	86	/*
	87	* Create the 8 bytes EBCDIC DCSS segment name from
	88	* an ASCII name, incl. padding
	89	*/
	90	static void dcss_mkname(char ascii_name, char ebcdic_name)
	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
	104	static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
	105	{
	106	return (u32 ) &monmsg->msg.rmmsg;
	107	}
	108
	109	static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
	110	{
	111	return (u32 ) &monmsg->msg.rmmsg[4];
	112	}
	113
	114	static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
	115	{
	116	return ((u8 ) mon_mca_start(monmsg) + monmsg->mca_offset + index);
	117	}
	118
	119	static inline u32 mon_mca_size(struct mon_msg *monmsg)
	120	{
	121	return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
	122	}
	123
	124	static inline u32 mon_rec_start(struct mon_msg *monmsg)
	125	{
	126	return ((u32 ) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
	127	}
	128
	129	static inline u32 mon_rec_end(struct mon_msg *monmsg)
	130	{
	131	return ((u32 ) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
	132	}
	133
	134	static int mon_check_mca(struct mon_msg *monmsg)
	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)))
	145	return -EINVAL;
	146	return 0;
	147	}
	148
	149	static int mon_send_reply(struct mon_msg *monmsg,
	150	struct mon_private *monpriv)
	151	{
	152	int rc;
	153
	154	rc = iucv_message_reply(monpriv->path, &monmsg->msg,
	155	IUCV_IPRMDATA, NULL, 0);
	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) {
	166	pr_err("Reading monitor data failed with rc=%i\n", rc);
	167	return -EIO;
	168	}
	169	return 0;
	170	}
	171
	172	static void mon_free_mem(struct mon_private *monpriv)
	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
	182	static struct mon_private *mon_alloc_mem(void)
	183	{
	184	int i;
	185	struct mon_private *monpriv;
	186
	187	monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
	188	if (!monpriv)
	189	return NULL;
	190	for (i = 0; i < MON_MSGLIM; i++) {
	191	monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
	192	GFP_KERNEL);
	193	if (!monpriv->msg_array[i]) {
	194	mon_free_mem(monpriv);
	195	return NULL;
	196	}
	197	}
	198	return monpriv;
	199	}
	200
	201	static inline void mon_next_mca(struct mon_msg *monmsg)
	202	{
	203	if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
	204	return;
	205	monmsg->mca_offset += 12;
	206	monmsg->pos = 0;
	207	}
	208
	209	static struct mon_msg mon_next_message(struct mon_private monpriv)
	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;
	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	*****************************************************************************/
	233	static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
	234	{
	235	struct mon_private *monpriv = path->private;
	236
	237	atomic_set(&monpriv->iucv_connected, 1);
	238	wake_up(&mon_conn_wait_queue);
	239	}
	240
	241	static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
	242	{
	243	struct mon_private *monpriv = path->private;
	244
	245	pr_err("z/VM *MONITOR system service disconnected with rc=%i\n",
	246	ipuser[0]);
	247	iucv_path_sever(path, NULL);
	248	atomic_set(&monpriv->iucv_severed, 1);
	249	wake_up(&mon_conn_wait_queue);
	250	wake_up_interruptible(&mon_read_wait_queue);
	251	}
	252
	253	static void mon_iucv_message_pending(struct iucv_path *path,
	254	struct iucv_message *msg)
	255	{
	256	struct mon_private *monpriv = path->private;
	257
	258	memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
	259	msg, sizeof(*msg));
	260	if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
	261	pr_warning("The read queue for monitor data is full\n");
	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
	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,
	273	};
	274
	275	/******************************************************************************
	276	* file operations *
	277	*****************************************************************************/
	278	static int mon_open(struct inode inode, struct file filp)
	279	{
	280	struct mon_private *monpriv;
	281	int rc;
	282
	283	/*
	284	* only one user allowed
	285	*/
	286	lock_kernel();
	287	rc = -EBUSY;
	288	if (test_and_set_bit(MON_IN_USE, &mon_in_use))
	289	goto out;
	290
	291	rc = -ENOMEM;
	292	monpriv = mon_alloc_mem();
	293	if (!monpriv)
	294	goto out_use;
	295
	296	/*
	297	* Connect to *MONITOR service
	298	*/
	299	monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
	300	if (!monpriv->path)
	301	goto out_priv;
	302	rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
	303	MON_SERVICE, NULL, user_data_connect, monpriv);
	304	if (rc) {
	305	pr_err("Connecting to the z/VM *MONITOR system service "
	306	"failed with rc=%i\n", rc);
	307	rc = -EIO;
	308	goto out_path;
	309	}
	310	/*
	311	* Wait for connection confirmation
	312	*/
	313	wait_event(mon_conn_wait_queue,
	314	atomic_read(&monpriv->iucv_connected) \|\|
	315	atomic_read(&monpriv->iucv_severed));
	316	if (atomic_read(&monpriv->iucv_severed)) {
	317	atomic_set(&monpriv->iucv_severed, 0);
	318	atomic_set(&monpriv->iucv_connected, 0);
	319	rc = -EIO;
	320	goto out_path;
	321	}
	322	filp->private_data = monpriv;
	323	monreader_device->driver_data = monpriv;
	324	unlock_kernel();
	325	return nonseekable_open(inode, filp);
	326
	327	out_path:
	328	iucv_path_free(monpriv->path);
	329	out_priv:
	330	mon_free_mem(monpriv);
	331	out_use:
	332	clear_bit(MON_IN_USE, &mon_in_use);
	333	out:
	334	unlock_kernel();
	335	return rc;
	336	}
	337
	338	static int mon_close(struct inode inode, struct file filp)
	339	{
	340	int rc, i;
	341	struct mon_private *monpriv = filp->private_data;
	342
	343	/*
	344	* Close IUCV connection and unregister
	345	*/
	346	if (monpriv->path) {
	347	rc = iucv_path_sever(monpriv->path, user_data_sever);
	348	if (rc)
	349	pr_warning("Disconnecting the z/VM *MONITOR system "
	350	"service failed with rc=%i\n", rc);
	351	iucv_path_free(monpriv->path);
	352	}
	353
	354	atomic_set(&monpriv->iucv_severed, 0);
	355	atomic_set(&monpriv->iucv_connected, 0);
	356	atomic_set(&monpriv->read_ready, 0);
	357	atomic_set(&monpriv->msglim_count, 0);
	358	monpriv->write_index = 0;
	359	monpriv->read_index = 0;
	360
	361	for (i = 0; i < MON_MSGLIM; i++)
	362	kfree(monpriv->msg_array[i]);
	363	kfree(monpriv);
	364	clear_bit(MON_IN_USE, &mon_in_use);
	365	return 0;
	366	}
	367
	368	static ssize_t mon_read(struct file filp, char __user data,
	369	size_t count, loff_t *ppos)
	370	{
	371	struct mon_private *monpriv = filp->private_data;
	372	struct mon_msg *monmsg;
	373	int ret;
	374	u32 mce_start;
	375
	376	monmsg = mon_next_message(monpriv);
	377	if (IS_ERR(monmsg))
	378	return PTR_ERR(monmsg);
	379
	380	if (!monmsg) {
	381	if (filp->f_flags & O_NONBLOCK)
	382	return -EAGAIN;
	383	ret = wait_event_interruptible(mon_read_wait_queue,
	384	atomic_read(&monpriv->read_ready) \|\|
	385	atomic_read(&monpriv->iucv_severed));
	386	if (ret)
	387	return ret;
	388	if (unlikely(atomic_read(&monpriv->iucv_severed)))
	389	return -EIO;
	390	monmsg = monpriv->msg_array[monpriv->read_index];
	391	}
	392
	393	if (!monmsg->pos)
	394	monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
	395	if (mon_check_mca(monmsg))
	396	goto reply;
	397
	398	/* read monitor control element (12 bytes) first */
	399	mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
	400	if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
	401	count = min(count, (size_t) mce_start + 12 - monmsg->pos);
	402	ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
	403	count);
	404	if (ret)
	405	return -EFAULT;
	406	monmsg->pos += count;
	407	if (monmsg->pos == mce_start + 12)
	408	monmsg->pos = mon_rec_start(monmsg);
	409	goto out_copy;
	410	}
	411
	412	/* read records */
	413	if (monmsg->pos <= mon_rec_end(monmsg)) {
	414	count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
	415	+ 1);
	416	ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
	417	count);
	418	if (ret)
	419	return -EFAULT;
	420	monmsg->pos += count;
	421	if (monmsg->pos > mon_rec_end(monmsg))
	422	mon_next_mca(monmsg);
	423	goto out_copy;
	424	}
	425	reply:
	426	ret = mon_send_reply(monmsg, monpriv);
	427	return ret;
	428
	429	out_copy:
	430	*ppos += count;
	431	return count;
	432	}
	433
	434	static unsigned int mon_poll(struct file filp, struct poll_table_struct p)
	435	{
	436	struct mon_private *monpriv = filp->private_data;
	437
	438	poll_wait(filp, &mon_read_wait_queue, p);
	439	if (unlikely(atomic_read(&monpriv->iucv_severed)))
	440	return POLLERR;
	441	if (atomic_read(&monpriv->read_ready))
	442	return POLLIN \| POLLRDNORM;
	443	return 0;
	444	}
	445
	446	static const struct file_operations mon_fops = {
	447	.owner = THIS_MODULE,
	448	.open = &mon_open,
	449	.release = &mon_close,
	450	.read = &mon_read,
	451	.poll = &mon_poll,
	452	};
	453
	454	static struct miscdevice mon_dev = {
	455	.name = "monreader",
	456	.fops = &mon_fops,
	457	.minor = MISC_DYNAMIC_MINOR,
	458	};
	459
	460
	461	/******************************************************************************
	462	* suspend / resume *
	463	*****************************************************************************/
	464	static int monreader_freeze(struct device *dev)
	465	{
	466	struct mon_private *monpriv = dev->driver_data;
	467	int rc;
	468
	469	if (!monpriv)
	470	return 0;
	471	if (monpriv->path) {
	472	rc = iucv_path_sever(monpriv->path, user_data_sever);
	473	if (rc)
	474	pr_warning("Disconnecting the z/VM *MONITOR system "
	475	"service failed with rc=%i\n", rc);
	476	iucv_path_free(monpriv->path);
	477	}
	478	atomic_set(&monpriv->iucv_severed, 0);
	479	atomic_set(&monpriv->iucv_connected, 0);
	480	atomic_set(&monpriv->read_ready, 0);
	481	atomic_set(&monpriv->msglim_count, 0);
	482	monpriv->write_index = 0;
	483	monpriv->read_index = 0;
	484	monpriv->path = NULL;
	485	return 0;
	486	}
	487
	488	static int monreader_thaw(struct device *dev)
	489	{
	490	struct mon_private *monpriv = dev->driver_data;
	491	int rc;
	492
	493	if (!monpriv)
	494	return 0;
	495	rc = -ENOMEM;
	496	monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
	497	if (!monpriv->path)
	498	goto out;
	499	rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
	500	MON_SERVICE, NULL, user_data_connect, monpriv);
	501	if (rc) {
	502	pr_err("Connecting to the z/VM *MONITOR system service "
	503	"failed with rc=%i\n", rc);
	504	goto out_path;
	505	}
	506	wait_event(mon_conn_wait_queue,
	507	atomic_read(&monpriv->iucv_connected) \|\|
	508	atomic_read(&monpriv->iucv_severed));
	509	if (atomic_read(&monpriv->iucv_severed))
	510	goto out_path;
	511	return 0;
	512	out_path:
	513	rc = -EIO;
	514	iucv_path_free(monpriv->path);
	515	monpriv->path = NULL;
	516	out:
	517	atomic_set(&monpriv->iucv_severed, 1);
	518	return rc;
	519	}
	520
	521	static int monreader_restore(struct device *dev)
	522	{
	523	int rc;
	524
	525	segment_unload(mon_dcss_name);
	526	rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
	527	&mon_dcss_start, &mon_dcss_end);
	528	if (rc < 0) {
	529	segment_warning(rc, mon_dcss_name);
	530	panic("fatal monreader resume error: no monitor dcss\n");
	531	}
	532	return monreader_thaw(dev);
	533	}
	534
	535	static struct dev_pm_ops monreader_pm_ops = {
	536	.freeze = monreader_freeze,
	537	.thaw = monreader_thaw,
	538	.restore = monreader_restore,
	539	};
	540
	541	static struct device_driver monreader_driver = {
	542	.name = "monreader",
	543	.bus = &iucv_bus,
	544	.pm = &monreader_pm_ops,
	545	};
	546
	547
	548	/******************************************************************************
	549	* module init/exit *
	550	*****************************************************************************/
	551	static int __init mon_init(void)
	552	{
	553	int rc;
	554
	555	if (!MACHINE_IS_VM) {
	556	pr_err("The z/VM *MONITOR record device driver cannot be "
	557	"loaded without z/VM\n");
	558	return -ENODEV;
	559	}
	560
	561	/*
	562	* Register with IUCV and connect to *MONITOR service
	563	*/
	564	rc = iucv_register(&monreader_iucv_handler, 1);
	565	if (rc) {
	566	pr_err("The z/VM *MONITOR record device driver failed to "
	567	"register with IUCV\n");
	568	return rc;
	569	}
	570
	571	rc = driver_register(&monreader_driver);
	572	if (rc)
	573	goto out_iucv;
	574	monreader_device = kzalloc(sizeof(struct device), GFP_KERNEL);
	575	if (!monreader_device)
	576	goto out_driver;
	577	dev_set_name(monreader_device, "monreader-dev");
	578	monreader_device->bus = &iucv_bus;
	579	monreader_device->parent = iucv_root;
	580	monreader_device->driver = &monreader_driver;
	581	monreader_device->release = (void ()(struct device ))kfree;
	582	rc = device_register(monreader_device);
	583	if (rc) {
	584	kfree(monreader_device);
	585	goto out_driver;
	586	}
	587
	588	rc = segment_type(mon_dcss_name);
	589	if (rc < 0) {
	590	segment_warning(rc, mon_dcss_name);
	591	goto out_device;
	592	}
	593	if (rc != SEG_TYPE_SC) {
	594	pr_err("The specified *MONITOR DCSS %s does not have the "
	595	"required type SC\n", mon_dcss_name);
	596	rc = -EINVAL;
	597	goto out_device;
	598	}
	599
	600	rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
	601	&mon_dcss_start, &mon_dcss_end);
	602	if (rc < 0) {
	603	segment_warning(rc, mon_dcss_name);
	604	rc = -EINVAL;
	605	goto out_device;
	606	}
	607	dcss_mkname(mon_dcss_name, &user_data_connect[8]);
	608
	609	rc = misc_register(&mon_dev);
	610	if (rc < 0 )
	611	goto out;
	612	return 0;
	613
	614	out:
	615	segment_unload(mon_dcss_name);
	616	out_device:
	617	device_unregister(monreader_device);
	618	out_driver:
	619	driver_unregister(&monreader_driver);
	620	out_iucv:
	621	iucv_unregister(&monreader_iucv_handler, 1);
	622	return rc;
	623	}
	624
	625	static void __exit mon_exit(void)
	626	{
	627	segment_unload(mon_dcss_name);
	628	WARN_ON(misc_deregister(&mon_dev) != 0);
	629	device_unregister(monreader_device);
	630	driver_unregister(&monreader_driver);
	631	iucv_unregister(&monreader_iucv_handler, 1);
	632	return;
	633	}
	634
	635
	636	module_init(mon_init);
	637	module_exit(mon_exit);
	638
	639	module_param_string(mondcss, mon_dcss_name, 9, 0444);
	640	MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
	641	"service, max. 8 chars. Default is MONDCSS");
	642
	643	MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
	644	MODULE_DESCRIPTION("Character device driver for reading z/VM "
	645	"monitor service records.");
	646	MODULE_LICENSE("GPL");