2 * drivers/s390/char/vmlogrdr.c
3 * character device driver for reading z/VM system service records
6 * Copyright IBM Corp. 2004, 2009
7 * character device driver for reading z/VM system service records,
9 * Author(s): Xenia Tkatschow <xenia@us.ibm.com>
10 * Stefan Weinhuber <wein@de.ibm.com>
14 #define KMSG_COMPONENT "vmlogrdr"
15 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/errno.h>
21 #include <linux/types.h>
22 #include <linux/interrupt.h>
23 #include <linux/spinlock.h>
24 #include <asm/atomic.h>
25 #include <asm/uaccess.h>
26 #include <asm/cpcmd.h>
27 #include <asm/debug.h>
28 #include <asm/ebcdic.h>
29 #include <net/iucv/iucv.h>
30 #include <linux/kmod.h>
31 #include <linux/cdev.h>
32 #include <linux/device.h>
33 #include <linux/smp_lock.h>
34 #include <linux/string.h>
37 ("(C) 2004 IBM Corporation by Xenia Tkatschow (xenia@us.ibm.com)\n"
38 " Stefan Weinhuber (wein@de.ibm.com)");
39 MODULE_DESCRIPTION ("Character device driver for reading z/VM "
40 "system service records.");
41 MODULE_LICENSE("GPL");
45 * The size of the buffer for iucv data transfer is one page,
46 * but in addition to the data we read from iucv we also
47 * place an integer and some characters into that buffer,
48 * so the maximum size for record data is a little less then
51 #define NET_BUFFER_SIZE (PAGE_SIZE - sizeof(int) - sizeof(FENCE))
54 * The elements that are concurrently accessed by bottom halves are
55 * connection_established, iucv_path_severed, local_interrupt_buffer
56 * and receive_ready. The first three can be protected by
57 * priv_lock. receive_ready is atomic, so it can be incremented and
58 * decremented without holding a lock.
59 * The variable dev_in_use needs to be protected by the lock, since
60 * it's a flag used by open to make sure that the device is opened only
61 * by one user at the same time.
63 struct vmlogrdr_priv_t {
64 char system_service[8];
65 char internal_name[8];
66 char recording_name[8];
67 struct iucv_path *path;
68 int connection_established;
69 int iucv_path_severed;
70 struct iucv_message local_interrupt_buffer;
71 atomic_t receive_ready;
74 char * current_position;
76 ulong residual_length;
78 int dev_in_use; /* 1: already opened, 0: not opened*/
80 struct device *device;
81 struct device *class_device;
88 * File operation structure for vmlogrdr devices
90 static int vmlogrdr_open(struct inode *, struct file *);
91 static int vmlogrdr_release(struct inode *, struct file *);
92 static ssize_t vmlogrdr_read (struct file *filp, char __user *data,
93 size_t count, loff_t * ppos);
95 static const struct file_operations vmlogrdr_fops = {
97 .open = vmlogrdr_open,
98 .release = vmlogrdr_release,
99 .read = vmlogrdr_read,
104 static void vmlogrdr_iucv_path_complete(struct iucv_path *, u8 ipuser[16]);
105 static void vmlogrdr_iucv_path_severed(struct iucv_path *, u8 ipuser[16]);
106 static void vmlogrdr_iucv_message_pending(struct iucv_path *,
107 struct iucv_message *);
110 static struct iucv_handler vmlogrdr_iucv_handler = {
111 .path_complete = vmlogrdr_iucv_path_complete,
112 .path_severed = vmlogrdr_iucv_path_severed,
113 .message_pending = vmlogrdr_iucv_message_pending,
117 static DECLARE_WAIT_QUEUE_HEAD(conn_wait_queue);
118 static DECLARE_WAIT_QUEUE_HEAD(read_wait_queue);
121 * pointer to system service private structure
122 * minor number 0 --> logrec
123 * minor number 1 --> account
124 * minor number 2 --> symptom
127 static struct vmlogrdr_priv_t sys_ser[] = {
128 { .system_service = "*LOGREC ",
129 .internal_name = "logrec",
130 .recording_name = "EREP",
133 .priv_lock = __SPIN_LOCK_UNLOCKED(sys_ser[0].priv_lock),
137 { .system_service = "*ACCOUNT",
138 .internal_name = "account",
139 .recording_name = "ACCOUNT",
142 .priv_lock = __SPIN_LOCK_UNLOCKED(sys_ser[1].priv_lock),
146 { .system_service = "*SYMPTOM",
147 .internal_name = "symptom",
148 .recording_name = "SYMPTOM",
151 .priv_lock = __SPIN_LOCK_UNLOCKED(sys_ser[2].priv_lock),
157 #define MAXMINOR (sizeof(sys_ser)/sizeof(struct vmlogrdr_priv_t))
159 static char FENCE[] = {"EOR"};
160 static int vmlogrdr_major = 0;
161 static struct cdev *vmlogrdr_cdev = NULL;
162 static int recording_class_AB;
165 static void vmlogrdr_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
167 struct vmlogrdr_priv_t * logptr = path->private;
169 spin_lock(&logptr->priv_lock);
170 logptr->connection_established = 1;
171 spin_unlock(&logptr->priv_lock);
172 wake_up(&conn_wait_queue);
176 static void vmlogrdr_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
178 struct vmlogrdr_priv_t * logptr = path->private;
179 u8 reason = (u8) ipuser[8];
181 pr_err("vmlogrdr: connection severed with reason %i\n", reason);
183 iucv_path_sever(path, NULL);
187 spin_lock(&logptr->priv_lock);
188 logptr->connection_established = 0;
189 logptr->iucv_path_severed = 1;
190 spin_unlock(&logptr->priv_lock);
192 wake_up(&conn_wait_queue);
193 /* just in case we're sleeping waiting for a record */
194 wake_up_interruptible(&read_wait_queue);
198 static void vmlogrdr_iucv_message_pending(struct iucv_path *path,
199 struct iucv_message *msg)
201 struct vmlogrdr_priv_t * logptr = path->private;
204 * This function is the bottom half so it should be quick.
205 * Copy the external interrupt data into our local eib and increment
208 spin_lock(&logptr->priv_lock);
209 memcpy(&logptr->local_interrupt_buffer, msg, sizeof(*msg));
210 atomic_inc(&logptr->receive_ready);
211 spin_unlock(&logptr->priv_lock);
212 wake_up_interruptible(&read_wait_queue);
216 static int vmlogrdr_get_recording_class_AB(void)
218 char cp_command[]="QUERY COMMAND RECORDING ";
219 char cp_response[80];
223 cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
224 len = strnlen(cp_response,sizeof(cp_response));
226 tail=strnchr(cp_response,len,'=');
230 if (!strncmp("ANY",tail,3))
232 if (!strncmp("NONE",tail,4))
235 * expect comma separated list of classes here, if one of them
236 * is A or B return 1 otherwise 0
238 for (i=tail-cp_response; i<len; i++)
239 if ( cp_response[i]=='A' || cp_response[i]=='B' )
245 static int vmlogrdr_recording(struct vmlogrdr_priv_t * logptr,
246 int action, int purge)
250 char cp_response[160];
251 char *onoff, *qid_string;
253 memset(cp_command, 0x00, sizeof(cp_command));
254 memset(cp_response, 0x00, sizeof(cp_response));
256 onoff = ((action == 1) ? "ON" : "OFF");
257 qid_string = ((recording_class_AB == 1) ? " QID * " : "");
260 * The recording commands needs to be called with option QID
261 * for guests that have previlege classes A or B.
262 * Purging has to be done as separate step, because recording
263 * can't be switched on as long as records are on the queue.
264 * Doing both at the same time doesn't work.
268 snprintf(cp_command, sizeof(cp_command),
269 "RECORDING %s PURGE %s",
270 logptr->recording_name,
273 cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
276 memset(cp_command, 0x00, sizeof(cp_command));
277 memset(cp_response, 0x00, sizeof(cp_response));
278 snprintf(cp_command, sizeof(cp_command), "RECORDING %s %s %s",
279 logptr->recording_name,
283 cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
284 /* The recording command will usually answer with 'Command complete'
285 * on success, but when the specific service was never connected
286 * before then there might be an additional informational message
287 * 'HCPCRC8072I Recording entry not found' before the
288 * 'Command complete'. So I use strstr rather then the strncmp.
290 if (strstr(cp_response,"Command complete"))
298 static int vmlogrdr_open (struct inode *inode, struct file *filp)
301 struct vmlogrdr_priv_t * logptr = NULL;
305 dev_num = iminor(inode);
306 if (dev_num > MAXMINOR)
308 logptr = &sys_ser[dev_num];
311 * only allow for blocking reads to be open
313 if (filp->f_flags & O_NONBLOCK)
316 /* Besure this device hasn't already been opened */
317 spin_lock_bh(&logptr->priv_lock);
318 if (logptr->dev_in_use) {
319 spin_unlock_bh(&logptr->priv_lock);
322 logptr->dev_in_use = 1;
323 logptr->connection_established = 0;
324 logptr->iucv_path_severed = 0;
325 atomic_set(&logptr->receive_ready, 0);
326 logptr->buffer_free = 1;
327 spin_unlock_bh(&logptr->priv_lock);
329 /* set the file options */
330 filp->private_data = logptr;
331 filp->f_op = &vmlogrdr_fops;
333 /* start recording for this service*/
334 if (logptr->autorecording) {
335 ret = vmlogrdr_recording(logptr,1,logptr->autopurge);
337 pr_warning("vmlogrdr: failed to start "
338 "recording automatically\n");
341 /* create connection to the system service */
342 logptr->path = iucv_path_alloc(10, 0, GFP_KERNEL);
345 connect_rc = iucv_path_connect(logptr->path, &vmlogrdr_iucv_handler,
346 logptr->system_service, NULL, NULL,
349 pr_err("vmlogrdr: iucv connection to %s "
350 "failed with rc %i \n",
351 logptr->system_service, connect_rc);
355 /* We've issued the connect and now we must wait for a
356 * ConnectionComplete or ConnectinSevered Interrupt
357 * before we can continue to process.
359 wait_event(conn_wait_queue, (logptr->connection_established)
360 || (logptr->iucv_path_severed));
361 if (logptr->iucv_path_severed)
363 nonseekable_open(inode, filp);
367 if (logptr->autorecording)
368 vmlogrdr_recording(logptr,0,logptr->autopurge);
370 kfree(logptr->path); /* kfree(NULL) is ok. */
373 logptr->dev_in_use = 0;
378 static int vmlogrdr_release (struct inode *inode, struct file *filp)
382 struct vmlogrdr_priv_t * logptr = filp->private_data;
384 iucv_path_sever(logptr->path, NULL);
387 if (logptr->autorecording) {
388 ret = vmlogrdr_recording(logptr,0,logptr->autopurge);
390 pr_warning("vmlogrdr: failed to stop "
391 "recording automatically\n");
393 logptr->dev_in_use = 0;
399 static int vmlogrdr_receive_data(struct vmlogrdr_priv_t *priv)
402 /* we need to keep track of two data sizes here:
403 * The number of bytes we need to receive from iucv and
404 * the total number of bytes we actually write into the buffer.
406 int user_data_count, iucv_data_count;
409 if (atomic_read(&priv->receive_ready)) {
410 spin_lock_bh(&priv->priv_lock);
411 if (priv->residual_length){
412 /* receive second half of a record */
413 iucv_data_count = priv->residual_length;
415 buffer = priv->buffer;
417 /* receive a new record:
418 * We need to return the total length of the record
419 * + size of FENCE in the first 4 bytes of the buffer.
421 iucv_data_count = priv->local_interrupt_buffer.length;
422 user_data_count = sizeof(int);
423 temp = (int*)priv->buffer;
424 *temp= iucv_data_count + sizeof(FENCE);
425 buffer = priv->buffer + sizeof(int);
428 * If the record is bigger than our buffer, we receive only
429 * a part of it. We can get the rest later.
431 if (iucv_data_count > NET_BUFFER_SIZE)
432 iucv_data_count = NET_BUFFER_SIZE;
433 rc = iucv_message_receive(priv->path,
434 &priv->local_interrupt_buffer,
435 0, buffer, iucv_data_count,
436 &priv->residual_length);
437 spin_unlock_bh(&priv->priv_lock);
438 /* An rc of 5 indicates that the record was bigger than
439 * the buffer, which is OK for us. A 9 indicates that the
440 * record was purged befor we could receive it.
445 atomic_set(&priv->receive_ready, 0);
450 priv->buffer_free = 0;
451 user_data_count += iucv_data_count;
452 priv->current_position = priv->buffer;
453 if (priv->residual_length == 0){
454 /* the whole record has been captured,
455 * now add the fence */
456 atomic_dec(&priv->receive_ready);
457 buffer = priv->buffer + user_data_count;
458 memcpy(buffer, FENCE, sizeof(FENCE));
459 user_data_count += sizeof(FENCE);
461 priv->remaining = user_data_count;
468 static ssize_t vmlogrdr_read(struct file *filp, char __user *data,
469 size_t count, loff_t * ppos)
472 struct vmlogrdr_priv_t * priv = filp->private_data;
474 while (priv->buffer_free) {
475 rc = vmlogrdr_receive_data(priv);
477 rc = wait_event_interruptible(read_wait_queue,
478 atomic_read(&priv->receive_ready));
483 /* copy only up to end of record */
484 if (count > priv->remaining)
485 count = priv->remaining;
487 if (copy_to_user(data, priv->current_position, count))
491 priv->current_position += count;
492 priv->remaining -= count;
494 /* if all data has been transferred, set buffer free */
495 if (priv->remaining == 0)
496 priv->buffer_free = 1;
501 static ssize_t vmlogrdr_autopurge_store(struct device * dev,
502 struct device_attribute *attr,
503 const char * buf, size_t count)
505 struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
522 static ssize_t vmlogrdr_autopurge_show(struct device *dev,
523 struct device_attribute *attr,
526 struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
527 return sprintf(buf, "%u\n", priv->autopurge);
531 static DEVICE_ATTR(autopurge, 0644, vmlogrdr_autopurge_show,
532 vmlogrdr_autopurge_store);
535 static ssize_t vmlogrdr_purge_store(struct device * dev,
536 struct device_attribute *attr,
537 const char * buf, size_t count)
541 char cp_response[80];
542 struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
547 memset(cp_command, 0x00, sizeof(cp_command));
548 memset(cp_response, 0x00, sizeof(cp_response));
551 * The recording command needs to be called with option QID
552 * for guests that have previlege classes A or B.
553 * Other guests will not recognize the command and we have to
554 * issue the same command without the QID parameter.
557 if (recording_class_AB)
558 snprintf(cp_command, sizeof(cp_command),
559 "RECORDING %s PURGE QID * ",
560 priv->recording_name);
562 snprintf(cp_command, sizeof(cp_command),
563 "RECORDING %s PURGE ",
564 priv->recording_name);
566 cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
572 static DEVICE_ATTR(purge, 0200, NULL, vmlogrdr_purge_store);
575 static ssize_t vmlogrdr_autorecording_store(struct device *dev,
576 struct device_attribute *attr,
577 const char *buf, size_t count)
579 struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
584 priv->autorecording=0;
587 priv->autorecording=1;
596 static ssize_t vmlogrdr_autorecording_show(struct device *dev,
597 struct device_attribute *attr,
600 struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
601 return sprintf(buf, "%u\n", priv->autorecording);
605 static DEVICE_ATTR(autorecording, 0644, vmlogrdr_autorecording_show,
606 vmlogrdr_autorecording_store);
609 static ssize_t vmlogrdr_recording_store(struct device * dev,
610 struct device_attribute *attr,
611 const char * buf, size_t count)
613 struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
618 ret = vmlogrdr_recording(priv,0,0);
621 ret = vmlogrdr_recording(priv,1,0);
634 static DEVICE_ATTR(recording, 0200, NULL, vmlogrdr_recording_store);
637 static ssize_t vmlogrdr_recording_status_show(struct device_driver *driver,
641 char cp_command[] = "QUERY RECORDING ";
644 cpcmd(cp_command, buf, 4096, NULL);
650 static DRIVER_ATTR(recording_status, 0444, vmlogrdr_recording_status_show,
653 static struct attribute *vmlogrdr_attrs[] = {
654 &dev_attr_autopurge.attr,
655 &dev_attr_purge.attr,
656 &dev_attr_autorecording.attr,
657 &dev_attr_recording.attr,
661 static int vmlogrdr_pm_prepare(struct device *dev)
664 struct vmlogrdr_priv_t *priv = dev_get_drvdata(dev);
668 spin_lock_bh(&priv->priv_lock);
669 if (priv->dev_in_use)
671 spin_unlock_bh(&priv->priv_lock);
674 pr_err("vmlogrdr: device %s is busy. Refuse to suspend.\n",
680 static const struct dev_pm_ops vmlogrdr_pm_ops = {
681 .prepare = vmlogrdr_pm_prepare,
684 static struct attribute_group vmlogrdr_attr_group = {
685 .attrs = vmlogrdr_attrs,
688 static struct class *vmlogrdr_class;
689 static struct device_driver vmlogrdr_driver = {
692 .pm = &vmlogrdr_pm_ops,
696 static int vmlogrdr_register_driver(void)
700 /* Register with iucv driver */
701 ret = iucv_register(&vmlogrdr_iucv_handler, 1);
705 ret = driver_register(&vmlogrdr_driver);
709 ret = driver_create_file(&vmlogrdr_driver,
710 &driver_attr_recording_status);
714 vmlogrdr_class = class_create(THIS_MODULE, "vmlogrdr");
715 if (IS_ERR(vmlogrdr_class)) {
716 ret = PTR_ERR(vmlogrdr_class);
717 vmlogrdr_class = NULL;
723 driver_remove_file(&vmlogrdr_driver, &driver_attr_recording_status);
725 driver_unregister(&vmlogrdr_driver);
727 iucv_unregister(&vmlogrdr_iucv_handler, 1);
733 static void vmlogrdr_unregister_driver(void)
735 class_destroy(vmlogrdr_class);
736 vmlogrdr_class = NULL;
737 driver_remove_file(&vmlogrdr_driver, &driver_attr_recording_status);
738 driver_unregister(&vmlogrdr_driver);
739 iucv_unregister(&vmlogrdr_iucv_handler, 1);
743 static int vmlogrdr_register_device(struct vmlogrdr_priv_t *priv)
748 dev = kzalloc(sizeof(struct device), GFP_KERNEL);
750 dev_set_name(dev, priv->internal_name);
751 dev->bus = &iucv_bus;
752 dev->parent = iucv_root;
753 dev->driver = &vmlogrdr_driver;
754 dev_set_drvdata(dev, priv);
756 * The release function could be called after the
757 * module has been unloaded. It's _only_ task is to
758 * free the struct. Therefore, we specify kfree()
759 * directly here. (Probably a little bit obfuscating
762 dev->release = (void (*)(struct device *))kfree;
765 ret = device_register(dev);
771 ret = sysfs_create_group(&dev->kobj, &vmlogrdr_attr_group);
773 device_unregister(dev);
776 priv->class_device = device_create(vmlogrdr_class, dev,
777 MKDEV(vmlogrdr_major,
779 priv, "%s", dev_name(dev));
780 if (IS_ERR(priv->class_device)) {
781 ret = PTR_ERR(priv->class_device);
782 priv->class_device=NULL;
783 sysfs_remove_group(&dev->kobj, &vmlogrdr_attr_group);
784 device_unregister(dev);
792 static int vmlogrdr_unregister_device(struct vmlogrdr_priv_t *priv)
794 device_destroy(vmlogrdr_class, MKDEV(vmlogrdr_major, priv->minor_num));
795 if (priv->device != NULL) {
796 sysfs_remove_group(&priv->device->kobj, &vmlogrdr_attr_group);
797 device_unregister(priv->device);
804 static int vmlogrdr_register_cdev(dev_t dev)
807 vmlogrdr_cdev = cdev_alloc();
808 if (!vmlogrdr_cdev) {
811 vmlogrdr_cdev->owner = THIS_MODULE;
812 vmlogrdr_cdev->ops = &vmlogrdr_fops;
813 vmlogrdr_cdev->dev = dev;
814 rc = cdev_add(vmlogrdr_cdev, vmlogrdr_cdev->dev, MAXMINOR);
818 // cleanup: cdev is not fully registered, no cdev_del here!
819 kobject_put(&vmlogrdr_cdev->kobj);
825 static void vmlogrdr_cleanup(void)
830 cdev_del(vmlogrdr_cdev);
833 for (i=0; i < MAXMINOR; ++i ) {
834 vmlogrdr_unregister_device(&sys_ser[i]);
835 free_page((unsigned long)sys_ser[i].buffer);
837 vmlogrdr_unregister_driver();
838 if (vmlogrdr_major) {
839 unregister_chrdev_region(MKDEV(vmlogrdr_major, 0), MAXMINOR);
845 static int __init vmlogrdr_init(void)
851 if (! MACHINE_IS_VM) {
852 pr_err("not running under VM, driver not loaded.\n");
856 recording_class_AB = vmlogrdr_get_recording_class_AB();
858 rc = alloc_chrdev_region(&dev, 0, MAXMINOR, "vmlogrdr");
861 vmlogrdr_major = MAJOR(dev);
863 rc=vmlogrdr_register_driver();
867 for (i=0; i < MAXMINOR; ++i ) {
868 sys_ser[i].buffer = (char *) get_zeroed_page(GFP_KERNEL);
869 if (!sys_ser[i].buffer) {
873 sys_ser[i].current_position = sys_ser[i].buffer;
874 rc=vmlogrdr_register_device(&sys_ser[i]);
881 rc = vmlogrdr_register_cdev(dev);
892 static void __exit vmlogrdr_exit(void)
899 module_init(vmlogrdr_init);
900 module_exit(vmlogrdr_exit);