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

/*
 * drivers/s390/char/monreader.c
 *
 * Character device driver for reading z/VM *MONITOR service records.
 *
 * Copyright 2004 IBM Corporation, IBM Deutschland Entwicklung GmbH.
 *
 * Author: Gerald Schaefer <geraldsc@de.ibm.com>
 */

#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 <asm/uaccess.h>
#include <asm/ebcdic.h>
#include <asm/extmem.h>
#include <linux/poll.h>
#include <net/iucv/iucv.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 inline 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);
}

/*
 * print appropriate error message for segment_load()/segment_type()
 * return code
 */
static void mon_segment_warn(int rc, char* seg_name)
{
	switch (rc) {
	case -ENOENT:
		P_WARNING("cannot load/query segment %s, does not exist\n",
			  seg_name);
		break;
	case -ENOSYS:
		P_WARNING("cannot load/query segment %s, not running on VM\n",
			  seg_name);
		break;
	case -EIO:
		P_WARNING("cannot load/query segment %s, hardware error\n",
			  seg_name);
		break;
	case -ENOTSUPP:
		P_WARNING("cannot load/query segment %s, is a multi-part "
			  "segment\n", seg_name);
		break;
	case -ENOSPC:
		P_WARNING("cannot load/query segment %s, overlaps with "
			  "storage\n", seg_name);
		break;
	case -EBUSY:
		P_WARNING("cannot load/query segment %s, overlaps with "
			  "already loaded dcss\n", seg_name);
		break;
	case -EPERM:
		P_WARNING("cannot load/query segment %s, already loaded in "
			  "incompatible mode\n", seg_name);
		break;
	case -ENOMEM:
		P_WARNING("cannot load/query segment %s, out of memory\n",
			  seg_name);
		break;
	case -ERANGE:
		P_WARNING("cannot load/query segment %s, exceeds kernel "
			  "mapping range\n", seg_name);
		break;
	default:
		P_WARNING("cannot load/query segment %s, return value %i\n",
			  seg_name, rc);
		break;
	}
}

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 inline 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)))
	{
		P_DEBUG("READ, IGNORED INVALID MCA\n\n");
		return -EINVAL;
	}
	return 0;
}

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

	P_DEBUG("read, REPLY: pathid = 0x%04X, msgid = 0x%08X, trgcls = "
		"0x%08X\n\n",
		monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);

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

	monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
	if (!monpriv) {
		P_ERROR("no memory for monpriv\n");
		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]) {
			P_ERROR("open, no memory for msg_array\n");
			mon_free_mem(monpriv);
			return NULL;
		}
	}
	return monpriv;
}

static inline void mon_read_debug(struct mon_msg *monmsg,
				  struct mon_private *monpriv)
{
#ifdef MON_DEBUG
	u8 msg_type[2], mca_type;
	unsigned long records_len;

	records_len = mon_rec_end(monmsg) - mon_rec_start(monmsg) + 1;

	memcpy(msg_type, &monmsg->msg.class, 2);
	EBCASC(msg_type, 2);
	mca_type = mon_mca_type(monmsg, 0);
	EBCASC(&mca_type, 1);

	P_DEBUG("read, mon_read_index = %i, mon_write_index = %i\n",
		monpriv->read_index, monpriv->write_index);
	P_DEBUG("read, pathid = 0x%04X, msgid = 0x%08X, trgcls = 0x%08X\n",
		monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);
	P_DEBUG("read, msg_type = '%c%c', mca_type = '%c' / 0x%X / 0x%X\n",
		msg_type[0], msg_type[1], mca_type ? mca_type : 'X',
		mon_mca_type(monmsg, 1), mon_mca_type(monmsg, 2));
	P_DEBUG("read, MCA: start = 0x%lX, end = 0x%lX\n",
		mon_mca_start(monmsg), mon_mca_end(monmsg));
	P_DEBUG("read, REC: start = 0x%X, end = 0x%X, len = %lu\n\n",
		mon_rec_start(monmsg), mon_rec_end(monmsg), records_len);
	if (mon_mca_size(monmsg) > 12)
		P_DEBUG("READ, MORE THAN ONE MCA\n\n");
#endif
}

static inline void mon_next_mca(struct mon_msg *monmsg)
{
	if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
		return;
	P_DEBUG("READ, NEXT MCA\n\n");
	monmsg->mca_offset += 12;
	monmsg->pos = 0;
}

static inline 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;
		P_WARNING("read, message limit reached\n");
		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;

	P_DEBUG("IUCV connection completed\n");
	P_DEBUG("IUCV ACCEPT (from *MONITOR): Version = 0x%02X, Event = "
		"0x%02X, Sample = 0x%02X\n",
		ipuser[0], ipuser[1], ipuser[2]);
	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;

	P_DEBUG("IUCV message pending\n");
	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
	 */
	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;
	}
	P_INFO("open, established connection to *MONITOR service\n\n");
	filp->private_data = monpriv;
	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:
	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);
	else
		P_INFO("close, terminated connection to *MONITOR service\n");

	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;
		mon_read_debug(monmsg, monpriv);
	}
	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;
	}
	P_INFO("open, registered with IUCV\n");

	rc = segment_type(mon_dcss_name);
	if (rc < 0) {
		mon_segment_warn(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) {
		mon_segment_warn(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 ) {
		P_ERROR("misc_register failed, rc = %i\n", rc);
		goto out;
	}
	P_INFO("Loaded segment %s from %p to %p, size = %lu Byte\n",
		mon_dcss_name, (void *) mon_dcss_start, (void *) mon_dcss_end,
		mon_dcss_end - mon_dcss_start + 1);
	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	*
c667aac8	6	* Copyright 2004 IBM Corporation, IBM Deutschland Entwicklung GmbH.
1da177e4 LT	7	*
	8	* Author: Gerald Schaefer <geraldsc@de.ibm.com>
	9	*/
	10
	11	#include <linux/module.h>
	12	#include <linux/moduleparam.h>
	13	#include <linux/init.h>
	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>
	21	#include <asm/uaccess.h>
	22	#include <asm/ebcdic.h>
	23	#include <asm/extmem.h>
	24	#include <linux/poll.h>
c667aac8	25	#include <net/iucv/iucv.h>
1da177e4 LT	26
	27
	28	//#define MON_DEBUG /* Debug messages on/off */
	29
	30	#define MON_NAME "monreader"
	31
	32	#define P_INFO(x...) printk(KERN_INFO MON_NAME " info: " x)
	33	#define P_ERROR(x...) printk(KERN_ERR MON_NAME " error: " x)
	34	#define P_WARNING(x...) printk(KERN_WARNING MON_NAME " warning: " x)
	35
	36	#ifdef MON_DEBUG
	37	#define P_DEBUG(x...) printk(KERN_DEBUG MON_NAME " debug: " x)
	38	#else
	39	#define P_DEBUG(x...) do {} while (0)
	40	#endif
	41
	42	#define MON_COLLECT_SAMPLE 0x80
	43	#define MON_COLLECT_EVENT 0x40
	44	#define MON_SERVICE "*MONITOR"
	45	#define MON_IN_USE 0x01
	46	#define MON_MSGLIM 255
	47
	48	static char mon_dcss_name[9] = "MONDCSS\0";
	49
	50	struct mon_msg {
	51	u32 pos;
	52	u32 mca_offset;
c667aac8	53	struct iucv_message msg;
1da177e4 LT	54	char msglim_reached;
	55	char replied_msglim;
	56	};
	57
	58	struct mon_private {
c667aac8	59	struct iucv_path *path;
1da177e4 LT	60	struct mon_msg *msg_array[MON_MSGLIM];
	61	unsigned int write_index;
	62	unsigned int read_index;
	63	atomic_t msglim_count;
	64	atomic_t read_ready;
	65	atomic_t iucv_connected;
	66	atomic_t iucv_severed;
	67	};
	68
	69	static unsigned long mon_in_use = 0;
	70
	71	static unsigned long mon_dcss_start;
	72	static unsigned long mon_dcss_end;
	73
	74	static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
	75	static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
	76
1da177e4 LT	77	static u8 user_data_connect[16] = {
	78	/* Version code, must be 0x01 for shared mode */
	79	0x01,
	80	/* what to collect */
	81	MON_COLLECT_SAMPLE \| MON_COLLECT_EVENT,
	82	/* DCSS name in EBCDIC, 8 bytes padded with blanks */
	83	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	84	0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	85	};
	86
	87	static u8 user_data_sever[16] = {
	88	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	89	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
	90	};
	91
	92
	93	/******************************************************************************
	94	* helper functions *
	95	*****************************************************************************/
	96	/*
	97	* Create the 8 bytes EBCDIC DCSS segment name from
	98	* an ASCII name, incl. padding
	99	*/
c667aac8	100	static inline void dcss_mkname(char ascii_name, char ebcdic_name)
1da177e4 LT	101	{
	102	int i;
	103
	104	for (i = 0; i < 8; i++) {
	105	if (ascii_name[i] == '\0')
	106	break;
	107	ebcdic_name[i] = toupper(ascii_name[i]);
	108	};
	109	for (; i < 8; i++)
	110	ebcdic_name[i] = ' ';
	111	ASCEBC(ebcdic_name, 8);
	112	}
	113
	114	/*
	115	* print appropriate error message for segment_load()/segment_type()
	116	* return code
	117	*/
c667aac8	118	static void mon_segment_warn(int rc, char* seg_name)
1da177e4 LT	119	{
	120	switch (rc) {
	121	case -ENOENT:
	122	P_WARNING("cannot load/query segment %s, does not exist\n",
	123	seg_name);
	124	break;
	125	case -ENOSYS:
	126	P_WARNING("cannot load/query segment %s, not running on VM\n",
	127	seg_name);
	128	break;
	129	case -EIO:
	130	P_WARNING("cannot load/query segment %s, hardware error\n",
	131	seg_name);
	132	break;
	133	case -ENOTSUPP:
	134	P_WARNING("cannot load/query segment %s, is a multi-part "
	135	"segment\n", seg_name);
	136	break;
	137	case -ENOSPC:
	138	P_WARNING("cannot load/query segment %s, overlaps with "
	139	"storage\n", seg_name);
	140	break;
	141	case -EBUSY:
	142	P_WARNING("cannot load/query segment %s, overlaps with "
	143	"already loaded dcss\n", seg_name);
	144	break;
	145	case -EPERM:
	146	P_WARNING("cannot load/query segment %s, already loaded in "
	147	"incompatible mode\n", seg_name);
	148	break;
	149	case -ENOMEM:
	150	P_WARNING("cannot load/query segment %s, out of memory\n",
	151	seg_name);
	152	break;
	153	case -ERANGE:
	154	P_WARNING("cannot load/query segment %s, exceeds kernel "
	155	"mapping range\n", seg_name);
	156	break;
	157	default:
	158	P_WARNING("cannot load/query segment %s, return value %i\n",
	159	seg_name, rc);
	160	break;
	161	}
	162	}
	163
c667aac8	164	static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
1da177e4	165	{
c667aac8	166	return (u32 ) &monmsg->msg.rmmsg;
1da177e4 LT	167	}
1da177e4 LT	168
c667aac8	169	static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
1da177e4	170	{
c667aac8	171	return (u32 ) &monmsg->msg.rmmsg[4];
1da177e4 LT	172	}
1da177e4 LT	173
c667aac8	174	static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
1da177e4 LT	175	{
	176	return ((u8 ) mon_mca_start(monmsg) + monmsg->mca_offset + index);
	177	}
	178
c667aac8	179	static inline u32 mon_mca_size(struct mon_msg *monmsg)
1da177e4 LT	180	{
	181	return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
	182	}
	183
c667aac8	184	static inline u32 mon_rec_start(struct mon_msg *monmsg)
1da177e4 LT	185	{
	186	return ((u32 ) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
	187	}
	188
c667aac8	189	static inline u32 mon_rec_end(struct mon_msg *monmsg)
1da177e4 LT	190	{
	191	return ((u32 ) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
	192	}
	193
c667aac8	194	static inline int mon_check_mca(struct mon_msg *monmsg)
1da177e4 LT	195	{
	196	if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) \|\|
	197	(mon_rec_start(monmsg) < mon_dcss_start) \|\|
	198	(mon_rec_end(monmsg) > mon_dcss_end) \|\|
	199	(mon_mca_type(monmsg, 0) == 0) \|\|
	200	(mon_mca_size(monmsg) % 12 != 0) \|\|
	201	(mon_mca_end(monmsg) <= mon_mca_start(monmsg)) \|\|
	202	(mon_mca_end(monmsg) > mon_dcss_end) \|\|
	203	(mon_mca_start(monmsg) < mon_dcss_start) \|\|
	204	((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
	205	{
	206	P_DEBUG("READ, IGNORED INVALID MCA\n\n");
	207	return -EINVAL;
	208	}
	209	return 0;
	210	}
	211
c667aac8 MS	212	static inline int mon_send_reply(struct mon_msg *monmsg,
c667aac8 MS	213	struct mon_private *monpriv)
1da177e4	214	{
1da177e4 LT	215	int rc;
	216
	217	P_DEBUG("read, REPLY: pathid = 0x%04X, msgid = 0x%08X, trgcls = "
	218	"0x%08X\n\n",
c667aac8 MS	219	monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);
	220
	221	rc = iucv_message_reply(monpriv->path, &monmsg->msg,
	222	IUCV_IPRMDATA, NULL, 0);
1da177e4 LT	223	atomic_dec(&monpriv->msglim_count);
	224	if (likely(!monmsg->msglim_reached)) {
	225	monmsg->pos = 0;
	226	monmsg->mca_offset = 0;
	227	monpriv->read_index = (monpriv->read_index + 1) %
	228	MON_MSGLIM;
	229	atomic_dec(&monpriv->read_ready);
	230	} else
	231	monmsg->replied_msglim = 1;
	232	if (rc) {
	233	P_ERROR("read, IUCV reply failed with rc = %i\n\n", rc);
	234	return -EIO;
	235	}
	236	return 0;
	237	}
	238
c667aac8 MS	239	static inline void mon_free_mem(struct mon_private *monpriv)
	240	{
	241	int i;
	242
	243	for (i = 0; i < MON_MSGLIM; i++)
	244	if (monpriv->msg_array[i])
	245	kfree(monpriv->msg_array[i]);
	246	kfree(monpriv);
	247	}
	248
	249	static inline struct mon_private *mon_alloc_mem(void)
1da177e4	250	{
c667aac8	251	int i;
1da177e4 LT	252	struct mon_private *monpriv;
1da177e4 LT	253
88abaab4	254	monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
1da177e4 LT	255	if (!monpriv) {
	256	P_ERROR("no memory for monpriv\n");
	257	return NULL;
	258	}
1da177e4	259	for (i = 0; i < MON_MSGLIM; i++) {
88abaab4	260	monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
1da177e4 LT	261	GFP_KERNEL);
	262	if (!monpriv->msg_array[i]) {
	263	P_ERROR("open, no memory for msg_array\n");
c667aac8	264	mon_free_mem(monpriv);
1da177e4 LT	265	return NULL;
1da177e4 LT	266	}
1da177e4 LT	267	}
	268	return monpriv;
	269	}
	270
c667aac8 MS	271	static inline void mon_read_debug(struct mon_msg *monmsg,
c667aac8 MS	272	struct mon_private *monpriv)
1da177e4 LT	273	{
	274	#ifdef MON_DEBUG
	275	u8 msg_type[2], mca_type;
	276	unsigned long records_len;
	277
	278	records_len = mon_rec_end(monmsg) - mon_rec_start(monmsg) + 1;
	279
c667aac8	280	memcpy(msg_type, &monmsg->msg.class, 2);
1da177e4 LT	281	EBCASC(msg_type, 2);
	282	mca_type = mon_mca_type(monmsg, 0);
	283	EBCASC(&mca_type, 1);
	284
	285	P_DEBUG("read, mon_read_index = %i, mon_write_index = %i\n",
	286	monpriv->read_index, monpriv->write_index);
	287	P_DEBUG("read, pathid = 0x%04X, msgid = 0x%08X, trgcls = 0x%08X\n",
c667aac8	288	monpriv->path->pathid, monmsg->msg.id, monmsg->msg.class);
1da177e4 LT	289	P_DEBUG("read, msg_type = '%c%c', mca_type = '%c' / 0x%X / 0x%X\n",
	290	msg_type[0], msg_type[1], mca_type ? mca_type : 'X',
	291	mon_mca_type(monmsg, 1), mon_mca_type(monmsg, 2));
	292	P_DEBUG("read, MCA: start = 0x%lX, end = 0x%lX\n",
	293	mon_mca_start(monmsg), mon_mca_end(monmsg));
	294	P_DEBUG("read, REC: start = 0x%X, end = 0x%X, len = %lu\n\n",
	295	mon_rec_start(monmsg), mon_rec_end(monmsg), records_len);
	296	if (mon_mca_size(monmsg) > 12)
	297	P_DEBUG("READ, MORE THAN ONE MCA\n\n");
	298	#endif
	299	}
	300
c667aac8	301	static inline void mon_next_mca(struct mon_msg *monmsg)
1da177e4 LT	302	{
	303	if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
	304	return;
	305	P_DEBUG("READ, NEXT MCA\n\n");
	306	monmsg->mca_offset += 12;
	307	monmsg->pos = 0;
	308	}
	309
c667aac8	310	static inline struct mon_msg mon_next_message(struct mon_private monpriv)
1da177e4 LT	311	{
	312	struct mon_msg *monmsg;
	313
	314	if (!atomic_read(&monpriv->read_ready))
	315	return NULL;
	316	monmsg = monpriv->msg_array[monpriv->read_index];
	317	if (unlikely(monmsg->replied_msglim)) {
	318	monmsg->replied_msglim = 0;
	319	monmsg->msglim_reached = 0;
	320	monmsg->pos = 0;
	321	monmsg->mca_offset = 0;
	322	P_WARNING("read, message limit reached\n");
	323	monpriv->read_index = (monpriv->read_index + 1) %
	324	MON_MSGLIM;
	325	atomic_dec(&monpriv->read_ready);
	326	return ERR_PTR(-EOVERFLOW);
	327	}
	328	return monmsg;
	329	}
	330
	331
	332	/******************************************************************************
	333	* IUCV handler *
	334	*****************************************************************************/
c667aac8	335	static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
1da177e4	336	{
c667aac8	337	struct mon_private *monpriv = path->private;
1da177e4 LT	338
	339	P_DEBUG("IUCV connection completed\n");
	340	P_DEBUG("IUCV ACCEPT (from *MONITOR): Version = 0x%02X, Event = "
	341	"0x%02X, Sample = 0x%02X\n",
c667aac8	342	ipuser[0], ipuser[1], ipuser[2]);
1da177e4 LT	343	atomic_set(&monpriv->iucv_connected, 1);
	344	wake_up(&mon_conn_wait_queue);
	345	}
	346
c667aac8	347	static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
1da177e4	348	{
c667aac8	349	struct mon_private *monpriv = path->private;
1da177e4	350
c667aac8 MS	351	P_ERROR("IUCV connection severed with rc = 0x%X\n", ipuser[0]);
c667aac8 MS	352	iucv_path_sever(path, NULL);
1da177e4 LT	353	atomic_set(&monpriv->iucv_severed, 1);
	354	wake_up(&mon_conn_wait_queue);
	355	wake_up_interruptible(&mon_read_wait_queue);
	356	}
	357
c667aac8 MS	358	static void mon_iucv_message_pending(struct iucv_path *path,
c667aac8 MS	359	struct iucv_message *msg)
1da177e4	360	{
c667aac8	361	struct mon_private *monpriv = path->private;
1da177e4 LT	362
1da177e4 LT	363	P_DEBUG("IUCV message pending\n");
c667aac8 MS	364	memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
c667aac8 MS	365	msg, sizeof(*msg));
1da177e4 LT	366	if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
	367	P_WARNING("IUCV message pending, message limit (%i) reached\n",
	368	MON_MSGLIM);
	369	monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
	370	}
	371	monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
	372	atomic_inc(&monpriv->read_ready);
	373	wake_up_interruptible(&mon_read_wait_queue);
	374	}
	375
c667aac8 MS	376	static struct iucv_handler monreader_iucv_handler = {
	377	.path_complete = mon_iucv_path_complete,
	378	.path_severed = mon_iucv_path_severed,
	379	.message_pending = mon_iucv_message_pending,
1da177e4 LT	380	};
	381
	382	/******************************************************************************
	383	* file operations *
	384	*****************************************************************************/
c667aac8	385	static int mon_open(struct inode inode, struct file filp)
1da177e4	386	{
1da177e4	387	struct mon_private *monpriv;
c667aac8	388	int rc;
1da177e4 LT	389
	390	/*
	391	* only one user allowed
	392	*/
c667aac8	393	rc = -EBUSY;
1da177e4	394	if (test_and_set_bit(MON_IN_USE, &mon_in_use))
c667aac8	395	goto out;
1da177e4	396
c667aac8	397	rc = -ENOMEM;
1da177e4 LT	398	monpriv = mon_alloc_mem();
1da177e4 LT	399	if (!monpriv)
c667aac8	400	goto out_use;
1da177e4 LT	401
1da177e4 LT	402	/*
c667aac8	403	* Connect to *MONITOR service
1da177e4	404	*/
c667aac8 MS	405	monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
	406	if (!monpriv->path)
	407	goto out_priv;
	408	rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
	409	MON_SERVICE, NULL, user_data_connect, monpriv);
1da177e4 LT	410	if (rc) {
	411	P_ERROR("iucv connection to *MONITOR failed with "
	412	"IPUSER SEVER code = %i\n", rc);
	413	rc = -EIO;
c667aac8	414	goto out_path;
1da177e4 LT	415	}
	416	/*
	417	* Wait for connection confirmation
	418	*/
	419	wait_event(mon_conn_wait_queue,
	420	atomic_read(&monpriv->iucv_connected) \|\|
	421	atomic_read(&monpriv->iucv_severed));
	422	if (atomic_read(&monpriv->iucv_severed)) {
	423	atomic_set(&monpriv->iucv_severed, 0);
	424	atomic_set(&monpriv->iucv_connected, 0);
	425	rc = -EIO;
c667aac8	426	goto out_path;
1da177e4 LT	427	}
	428	P_INFO("open, established connection to *MONITOR service\n\n");
	429	filp->private_data = monpriv;
	430	return nonseekable_open(inode, filp);
	431
c667aac8 MS	432	out_path:
	433	kfree(monpriv->path);
	434	out_priv:
	435	mon_free_mem(monpriv);
	436	out_use:
1da177e4	437	clear_bit(MON_IN_USE, &mon_in_use);
c667aac8	438	out:
1da177e4 LT	439	return rc;
	440	}
	441
c667aac8	442	static int mon_close(struct inode inode, struct file filp)
1da177e4 LT	443	{
	444	int rc, i;
	445	struct mon_private *monpriv = filp->private_data;
	446
	447	/*
	448	* Close IUCV connection and unregister
	449	*/
c667aac8	450	rc = iucv_path_sever(monpriv->path, user_data_sever);
1da177e4 LT	451	if (rc)
	452	P_ERROR("close, iucv_sever failed with rc = %i\n", rc);
	453	else
	454	P_INFO("close, terminated connection to *MONITOR service\n");
	455
1da177e4 LT	456	atomic_set(&monpriv->iucv_severed, 0);
	457	atomic_set(&monpriv->iucv_connected, 0);
	458	atomic_set(&monpriv->read_ready, 0);
	459	atomic_set(&monpriv->msglim_count, 0);
	460	monpriv->write_index = 0;
	461	monpriv->read_index = 0;
	462
	463	for (i = 0; i < MON_MSGLIM; i++)
	464	kfree(monpriv->msg_array[i]);
	465	kfree(monpriv);
	466	clear_bit(MON_IN_USE, &mon_in_use);
	467	return 0;
	468	}
	469
c667aac8 MS	470	static ssize_t mon_read(struct file filp, char __user data,
c667aac8 MS	471	size_t count, loff_t *ppos)
1da177e4 LT	472	{
	473	struct mon_private *monpriv = filp->private_data;
	474	struct mon_msg *monmsg;
	475	int ret;
	476	u32 mce_start;
	477
	478	monmsg = mon_next_message(monpriv);
	479	if (IS_ERR(monmsg))
	480	return PTR_ERR(monmsg);
	481
	482	if (!monmsg) {
	483	if (filp->f_flags & O_NONBLOCK)
	484	return -EAGAIN;
	485	ret = wait_event_interruptible(mon_read_wait_queue,
	486	atomic_read(&monpriv->read_ready) \|\|
	487	atomic_read(&monpriv->iucv_severed));
	488	if (ret)
	489	return ret;
	490	if (unlikely(atomic_read(&monpriv->iucv_severed)))
	491	return -EIO;
	492	monmsg = monpriv->msg_array[monpriv->read_index];
	493	}
	494
	495	if (!monmsg->pos) {
	496	monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
	497	mon_read_debug(monmsg, monpriv);
	498	}
	499	if (mon_check_mca(monmsg))
	500	goto reply;
	501
	502	/* read monitor control element (12 bytes) first */
	503	mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
	504	if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
	505	count = min(count, (size_t) mce_start + 12 - monmsg->pos);
	506	ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
	507	count);
	508	if (ret)
	509	return -EFAULT;
	510	monmsg->pos += count;
	511	if (monmsg->pos == mce_start + 12)
	512	monmsg->pos = mon_rec_start(monmsg);
	513	goto out_copy;
	514	}
	515
	516	/* read records */
	517	if (monmsg->pos <= mon_rec_end(monmsg)) {
	518	count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
	519	+ 1);
	520	ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
	521	count);
	522	if (ret)
	523	return -EFAULT;
	524	monmsg->pos += count;
	525	if (monmsg->pos > mon_rec_end(monmsg))
	526	mon_next_mca(monmsg);
	527	goto out_copy;
	528	}
	529	reply:
	530	ret = mon_send_reply(monmsg, monpriv);
	531	return ret;
	532
	533	out_copy:
	534	*ppos += count;
	535	return count;
536	}
537
c667aac8	538	static unsigned int mon_poll(struct file filp, struct poll_table_struct p)
1da177e4 LT	539	{
	540	struct mon_private *monpriv = filp->private_data;
	541
	542	poll_wait(filp, &mon_read_wait_queue, p);
	543	if (unlikely(atomic_read(&monpriv->iucv_severed)))
	544	return POLLERR;
	545	if (atomic_read(&monpriv->read_ready))
	546	return POLLIN \| POLLRDNORM;
	547	return 0;
	548	}
	549
d54b1fdb	550	static const struct file_operations mon_fops = {
1da177e4 LT	551	.owner = THIS_MODULE,
	552	.open = &mon_open,
	553	.release = &mon_close,
	554	.read = &mon_read,
	555	.poll = &mon_poll,
	556	};
	557
	558	static struct miscdevice mon_dev = {
	559	.name = "monreader",
1da177e4 LT	560	.fops = &mon_fops,
	561	.minor = MISC_DYNAMIC_MINOR,
	562	};
	563
	564	/******************************************************************************
	565	* module init/exit *
	566	*****************************************************************************/
c667aac8	567	static int __init mon_init(void)
1da177e4 LT	568	{
	569	int rc;
	570
	571	if (!MACHINE_IS_VM) {
	572	P_ERROR("not running under z/VM, driver not loaded\n");
	573	return -ENODEV;
	574	}
	575
c667aac8 MS	576	/*
	577	* Register with IUCV and connect to *MONITOR service
	578	*/
	579	rc = iucv_register(&monreader_iucv_handler, 1);
	580	if (rc) {
	581	P_ERROR("failed to register with iucv driver\n");
	582	return rc;
	583	}
	584	P_INFO("open, registered with IUCV\n");
	585
1da177e4 LT	586	rc = segment_type(mon_dcss_name);
	587	if (rc < 0) {
	588	mon_segment_warn(rc, mon_dcss_name);
c667aac8	589	goto out_iucv;
1da177e4 LT	590	}
	591	if (rc != SEG_TYPE_SC) {
	592	P_ERROR("segment %s has unsupported type, should be SC\n",
	593	mon_dcss_name);
c667aac8 MS	594	rc = -EINVAL;
c667aac8 MS	595	goto out_iucv;
1da177e4 LT	596	}
	597
	598	rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
	599	&mon_dcss_start, &mon_dcss_end);
	600	if (rc < 0) {
	601	mon_segment_warn(rc, mon_dcss_name);
c667aac8 MS	602	rc = -EINVAL;
c667aac8 MS	603	goto out_iucv;
1da177e4 LT	604	}
	605	dcss_mkname(mon_dcss_name, &user_data_connect[8]);
	606
	607	rc = misc_register(&mon_dev);
	608	if (rc < 0 ) {
	609	P_ERROR("misc_register failed, rc = %i\n", rc);
	610	goto out;
	611	}
	612	P_INFO("Loaded segment %s from %p to %p, size = %lu Byte\n",
	613	mon_dcss_name, (void ) mon_dcss_start, (void ) mon_dcss_end,
	614	mon_dcss_end - mon_dcss_start + 1);
	615	return 0;
	616
	617	out:
	618	segment_unload(mon_dcss_name);
c667aac8 MS	619	out_iucv:
c667aac8 MS	620	iucv_unregister(&monreader_iucv_handler, 1);
1da177e4 LT	621	return rc;
	622	}
	623
c667aac8	624	static void __exit mon_exit(void)
1da177e4 LT	625	{
	626	segment_unload(mon_dcss_name);
	627	WARN_ON(misc_deregister(&mon_dev) != 0);
c667aac8	628	iucv_unregister(&monreader_iucv_handler, 1);
1da177e4 LT	629	return;
	630	}
	631
	632
	633	module_init(mon_init);
	634	module_exit(mon_exit);
	635
	636	module_param_string(mondcss, mon_dcss_name, 9, 0444);
	637	MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
	638	"service, max. 8 chars. Default is MONDCSS");
	639
	640	MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
	641	MODULE_DESCRIPTION("Character device driver for reading z/VM "
	642	"monitor service records.");
	643	MODULE_LICENSE("GPL");