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/errno.h> 16 #include <linux/types.h> 17 #include <linux/kernel.h> 18 #include <linux/miscdevice.h> 19 #include <linux/ctype.h> 20 #include <linux/spinlock.h> 21 #include <linux/interrupt.h> 22 #include <linux/poll.h> 23 #include <linux/device.h> 24 #include <net/iucv/iucv.h> 25 #include <asm/uaccess.h> 26 #include <asm/ebcdic.h> 27 #include <asm/extmem.h> 28 29 30 #define MON_COLLECT_SAMPLE 0x80 31 #define MON_COLLECT_EVENT 0x40 32 #define MON_SERVICE "*MONITOR" 33 #define MON_IN_USE 0x01 34 #define MON_MSGLIM 255 35 36 static char mon_dcss_name[9] = "MONDCSS\0"; 37 38 struct mon_msg { 39 u32 pos; 40 u32 mca_offset; 41 struct iucv_message msg; 42 char msglim_reached; 43 char replied_msglim; 44 }; 45 46 struct mon_private { 47 struct iucv_path *path; 48 struct mon_msg *msg_array[MON_MSGLIM]; 49 unsigned int write_index; 50 unsigned int read_index; 51 atomic_t msglim_count; 52 atomic_t read_ready; 53 atomic_t iucv_connected; 54 atomic_t iucv_severed; 55 }; 56 57 static unsigned long mon_in_use = 0; 58 59 static unsigned long mon_dcss_start; 60 static unsigned long mon_dcss_end; 61 62 static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue); 63 static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue); 64 65 static u8 user_data_connect[16] = { 66 /* Version code, must be 0x01 for shared mode */ 67 0x01, 68 /* what to collect */ 69 MON_COLLECT_SAMPLE | MON_COLLECT_EVENT, 70 /* DCSS name in EBCDIC, 8 bytes padded with blanks */ 71 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 72 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 73 }; 74 75 static u8 user_data_sever[16] = { 76 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 77 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 78 }; 79 80 static struct device *monreader_device; 81 82 /****************************************************************************** 83 * helper functions * 84 *****************************************************************************/ 85 /* 86 * Create the 8 bytes EBCDIC DCSS segment name from 87 * an ASCII name, incl. padding 88 */ 89 static void dcss_mkname(char *ascii_name, char *ebcdic_name) 90 { 91 int i; 92 93 for (i = 0; i < 8; i++) { 94 if (ascii_name[i] == '\0') 95 break; 96 ebcdic_name[i] = toupper(ascii_name[i]); 97 }; 98 for (; i < 8; i++) 99 ebcdic_name[i] = ' '; 100 ASCEBC(ebcdic_name, 8); 101 } 102 103 static inline unsigned long mon_mca_start(struct mon_msg *monmsg) 104 { 105 return *(u32 *) &monmsg->msg.rmmsg; 106 } 107 108 static inline unsigned long mon_mca_end(struct mon_msg *monmsg) 109 { 110 return *(u32 *) &monmsg->msg.rmmsg[4]; 111 } 112 113 static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index) 114 { 115 return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index); 116 } 117 118 static inline u32 mon_mca_size(struct mon_msg *monmsg) 119 { 120 return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1; 121 } 122 123 static inline u32 mon_rec_start(struct mon_msg *monmsg) 124 { 125 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4)); 126 } 127 128 static inline u32 mon_rec_end(struct mon_msg *monmsg) 129 { 130 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8)); 131 } 132 133 static int mon_check_mca(struct mon_msg *monmsg) 134 { 135 if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) || 136 (mon_rec_start(monmsg) < mon_dcss_start) || 137 (mon_rec_end(monmsg) > mon_dcss_end) || 138 (mon_mca_type(monmsg, 0) == 0) || 139 (mon_mca_size(monmsg) % 12 != 0) || 140 (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) || 141 (mon_mca_end(monmsg) > mon_dcss_end) || 142 (mon_mca_start(monmsg) < mon_dcss_start) || 143 ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0))) 144 return -EINVAL; 145 return 0; 146 } 147 148 static int mon_send_reply(struct mon_msg *monmsg, 149 struct mon_private *monpriv) 150 { 151 int rc; 152 153 rc = iucv_message_reply(monpriv->path, &monmsg->msg, 154 IUCV_IPRMDATA, NULL, 0); 155 atomic_dec(&monpriv->msglim_count); 156 if (likely(!monmsg->msglim_reached)) { 157 monmsg->pos = 0; 158 monmsg->mca_offset = 0; 159 monpriv->read_index = (monpriv->read_index + 1) % 160 MON_MSGLIM; 161 atomic_dec(&monpriv->read_ready); 162 } else 163 monmsg->replied_msglim = 1; 164 if (rc) { 165 pr_err("Reading monitor data failed with rc=%i\n", rc); 166 return -EIO; 167 } 168 return 0; 169 } 170 171 static void mon_free_mem(struct mon_private *monpriv) 172 { 173 int i; 174 175 for (i = 0; i < MON_MSGLIM; i++) 176 if (monpriv->msg_array[i]) 177 kfree(monpriv->msg_array[i]); 178 kfree(monpriv); 179 } 180 181 static struct mon_private *mon_alloc_mem(void) 182 { 183 int i; 184 struct mon_private *monpriv; 185 186 monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL); 187 if (!monpriv) 188 return NULL; 189 for (i = 0; i < MON_MSGLIM; i++) { 190 monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg), 191 GFP_KERNEL); 192 if (!monpriv->msg_array[i]) { 193 mon_free_mem(monpriv); 194 return NULL; 195 } 196 } 197 return monpriv; 198 } 199 200 static inline void mon_next_mca(struct mon_msg *monmsg) 201 { 202 if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12)) 203 return; 204 monmsg->mca_offset += 12; 205 monmsg->pos = 0; 206 } 207 208 static struct mon_msg *mon_next_message(struct mon_private *monpriv) 209 { 210 struct mon_msg *monmsg; 211 212 if (!atomic_read(&monpriv->read_ready)) 213 return NULL; 214 monmsg = monpriv->msg_array[monpriv->read_index]; 215 if (unlikely(monmsg->replied_msglim)) { 216 monmsg->replied_msglim = 0; 217 monmsg->msglim_reached = 0; 218 monmsg->pos = 0; 219 monmsg->mca_offset = 0; 220 monpriv->read_index = (monpriv->read_index + 1) % 221 MON_MSGLIM; 222 atomic_dec(&monpriv->read_ready); 223 return ERR_PTR(-EOVERFLOW); 224 } 225 return monmsg; 226 } 227 228 229 /****************************************************************************** 230 * IUCV handler * 231 *****************************************************************************/ 232 static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16]) 233 { 234 struct mon_private *monpriv = path->private; 235 236 atomic_set(&monpriv->iucv_connected, 1); 237 wake_up(&mon_conn_wait_queue); 238 } 239 240 static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16]) 241 { 242 struct mon_private *monpriv = path->private; 243 244 pr_err("z/VM *MONITOR system service disconnected with rc=%i\n", 245 ipuser[0]); 246 iucv_path_sever(path, NULL); 247 atomic_set(&monpriv->iucv_severed, 1); 248 wake_up(&mon_conn_wait_queue); 249 wake_up_interruptible(&mon_read_wait_queue); 250 } 251 252 static void mon_iucv_message_pending(struct iucv_path *path, 253 struct iucv_message *msg) 254 { 255 struct mon_private *monpriv = path->private; 256 257 memcpy(&monpriv->msg_array[monpriv->write_index]->msg, 258 msg, sizeof(*msg)); 259 if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) { 260 pr_warning("The read queue for monitor data is full\n"); 261 monpriv->msg_array[monpriv->write_index]->msglim_reached = 1; 262 } 263 monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM; 264 atomic_inc(&monpriv->read_ready); 265 wake_up_interruptible(&mon_read_wait_queue); 266 } 267 268 static struct iucv_handler monreader_iucv_handler = { 269 .path_complete = mon_iucv_path_complete, 270 .path_severed = mon_iucv_path_severed, 271 .message_pending = mon_iucv_message_pending, 272 }; 273 274 /****************************************************************************** 275 * file operations * 276 *****************************************************************************/ 277 static int mon_open(struct inode *inode, struct file *filp) 278 { 279 struct mon_private *monpriv; 280 int rc; 281 282 /* 283 * only one user allowed 284 */ 285 rc = -EBUSY; 286 if (test_and_set_bit(MON_IN_USE, &mon_in_use)) 287 goto out; 288 289 rc = -ENOMEM; 290 monpriv = mon_alloc_mem(); 291 if (!monpriv) 292 goto out_use; 293 294 /* 295 * Connect to *MONITOR service 296 */ 297 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL); 298 if (!monpriv->path) 299 goto out_priv; 300 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler, 301 MON_SERVICE, NULL, user_data_connect, monpriv); 302 if (rc) { 303 pr_err("Connecting to the z/VM *MONITOR system service " 304 "failed with rc=%i\n", rc); 305 rc = -EIO; 306 goto out_path; 307 } 308 /* 309 * Wait for connection confirmation 310 */ 311 wait_event(mon_conn_wait_queue, 312 atomic_read(&monpriv->iucv_connected) || 313 atomic_read(&monpriv->iucv_severed)); 314 if (atomic_read(&monpriv->iucv_severed)) { 315 atomic_set(&monpriv->iucv_severed, 0); 316 atomic_set(&monpriv->iucv_connected, 0); 317 rc = -EIO; 318 goto out_path; 319 } 320 filp->private_data = monpriv; 321 dev_set_drvdata(monreader_device, monpriv); 322 return nonseekable_open(inode, filp); 323 324 out_path: 325 iucv_path_free(monpriv->path); 326 out_priv: 327 mon_free_mem(monpriv); 328 out_use: 329 clear_bit(MON_IN_USE, &mon_in_use); 330 out: 331 return rc; 332 } 333 334 static int mon_close(struct inode *inode, struct file *filp) 335 { 336 int rc, i; 337 struct mon_private *monpriv = filp->private_data; 338 339 /* 340 * Close IUCV connection and unregister 341 */ 342 if (monpriv->path) { 343 rc = iucv_path_sever(monpriv->path, user_data_sever); 344 if (rc) 345 pr_warning("Disconnecting the z/VM *MONITOR system " 346 "service failed with rc=%i\n", rc); 347 iucv_path_free(monpriv->path); 348 } 349 350 atomic_set(&monpriv->iucv_severed, 0); 351 atomic_set(&monpriv->iucv_connected, 0); 352 atomic_set(&monpriv->read_ready, 0); 353 atomic_set(&monpriv->msglim_count, 0); 354 monpriv->write_index = 0; 355 monpriv->read_index = 0; 356 dev_set_drvdata(monreader_device, NULL); 357 358 for (i = 0; i < MON_MSGLIM; i++) 359 kfree(monpriv->msg_array[i]); 360 kfree(monpriv); 361 clear_bit(MON_IN_USE, &mon_in_use); 362 return 0; 363 } 364 365 static ssize_t mon_read(struct file *filp, char __user *data, 366 size_t count, loff_t *ppos) 367 { 368 struct mon_private *monpriv = filp->private_data; 369 struct mon_msg *monmsg; 370 int ret; 371 u32 mce_start; 372 373 monmsg = mon_next_message(monpriv); 374 if (IS_ERR(monmsg)) 375 return PTR_ERR(monmsg); 376 377 if (!monmsg) { 378 if (filp->f_flags & O_NONBLOCK) 379 return -EAGAIN; 380 ret = wait_event_interruptible(mon_read_wait_queue, 381 atomic_read(&monpriv->read_ready) || 382 atomic_read(&monpriv->iucv_severed)); 383 if (ret) 384 return ret; 385 if (unlikely(atomic_read(&monpriv->iucv_severed))) 386 return -EIO; 387 monmsg = monpriv->msg_array[monpriv->read_index]; 388 } 389 390 if (!monmsg->pos) 391 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset; 392 if (mon_check_mca(monmsg)) 393 goto reply; 394 395 /* read monitor control element (12 bytes) first */ 396 mce_start = mon_mca_start(monmsg) + monmsg->mca_offset; 397 if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) { 398 count = min(count, (size_t) mce_start + 12 - monmsg->pos); 399 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, 400 count); 401 if (ret) 402 return -EFAULT; 403 monmsg->pos += count; 404 if (monmsg->pos == mce_start + 12) 405 monmsg->pos = mon_rec_start(monmsg); 406 goto out_copy; 407 } 408 409 /* read records */ 410 if (monmsg->pos <= mon_rec_end(monmsg)) { 411 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos 412 + 1); 413 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, 414 count); 415 if (ret) 416 return -EFAULT; 417 monmsg->pos += count; 418 if (monmsg->pos > mon_rec_end(monmsg)) 419 mon_next_mca(monmsg); 420 goto out_copy; 421 } 422 reply: 423 ret = mon_send_reply(monmsg, monpriv); 424 return ret; 425 426 out_copy: 427 *ppos += count; 428 return count; 429 } 430 431 static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p) 432 { 433 struct mon_private *monpriv = filp->private_data; 434 435 poll_wait(filp, &mon_read_wait_queue, p); 436 if (unlikely(atomic_read(&monpriv->iucv_severed))) 437 return POLLERR; 438 if (atomic_read(&monpriv->read_ready)) 439 return POLLIN | POLLRDNORM; 440 return 0; 441 } 442 443 static const struct file_operations mon_fops = { 444 .owner = THIS_MODULE, 445 .open = &mon_open, 446 .release = &mon_close, 447 .read = &mon_read, 448 .poll = &mon_poll, 449 }; 450 451 static struct miscdevice mon_dev = { 452 .name = "monreader", 453 .fops = &mon_fops, 454 .minor = MISC_DYNAMIC_MINOR, 455 }; 456 457 458 /****************************************************************************** 459 * suspend / resume * 460 *****************************************************************************/ 461 static int monreader_freeze(struct device *dev) 462 { 463 struct mon_private *monpriv = dev_get_drvdata(dev); 464 int rc; 465 466 if (!monpriv) 467 return 0; 468 if (monpriv->path) { 469 rc = iucv_path_sever(monpriv->path, user_data_sever); 470 if (rc) 471 pr_warning("Disconnecting the z/VM *MONITOR system " 472 "service failed with rc=%i\n", rc); 473 iucv_path_free(monpriv->path); 474 } 475 atomic_set(&monpriv->iucv_severed, 0); 476 atomic_set(&monpriv->iucv_connected, 0); 477 atomic_set(&monpriv->read_ready, 0); 478 atomic_set(&monpriv->msglim_count, 0); 479 monpriv->write_index = 0; 480 monpriv->read_index = 0; 481 monpriv->path = NULL; 482 return 0; 483 } 484 485 static int monreader_thaw(struct device *dev) 486 { 487 struct mon_private *monpriv = dev_get_drvdata(dev); 488 int rc; 489 490 if (!monpriv) 491 return 0; 492 rc = -ENOMEM; 493 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL); 494 if (!monpriv->path) 495 goto out; 496 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler, 497 MON_SERVICE, NULL, user_data_connect, monpriv); 498 if (rc) { 499 pr_err("Connecting to the z/VM *MONITOR system service " 500 "failed with rc=%i\n", rc); 501 goto out_path; 502 } 503 wait_event(mon_conn_wait_queue, 504 atomic_read(&monpriv->iucv_connected) || 505 atomic_read(&monpriv->iucv_severed)); 506 if (atomic_read(&monpriv->iucv_severed)) 507 goto out_path; 508 return 0; 509 out_path: 510 rc = -EIO; 511 iucv_path_free(monpriv->path); 512 monpriv->path = NULL; 513 out: 514 atomic_set(&monpriv->iucv_severed, 1); 515 return rc; 516 } 517 518 static int monreader_restore(struct device *dev) 519 { 520 int rc; 521 522 segment_unload(mon_dcss_name); 523 rc = segment_load(mon_dcss_name, SEGMENT_SHARED, 524 &mon_dcss_start, &mon_dcss_end); 525 if (rc < 0) { 526 segment_warning(rc, mon_dcss_name); 527 panic("fatal monreader resume error: no monitor dcss\n"); 528 } 529 return monreader_thaw(dev); 530 } 531 532 static const struct dev_pm_ops monreader_pm_ops = { 533 .freeze = monreader_freeze, 534 .thaw = monreader_thaw, 535 .restore = monreader_restore, 536 }; 537 538 static struct device_driver monreader_driver = { 539 .name = "monreader", 540 .bus = &iucv_bus, 541 .pm = &monreader_pm_ops, 542 }; 543 544 545 /****************************************************************************** 546 * module init/exit * 547 *****************************************************************************/ 548 static int __init mon_init(void) 549 { 550 int rc; 551 552 if (!MACHINE_IS_VM) { 553 pr_err("The z/VM *MONITOR record device driver cannot be " 554 "loaded without z/VM\n"); 555 return -ENODEV; 556 } 557 558 /* 559 * Register with IUCV and connect to *MONITOR service 560 */ 561 rc = iucv_register(&monreader_iucv_handler, 1); 562 if (rc) { 563 pr_err("The z/VM *MONITOR record device driver failed to " 564 "register with IUCV\n"); 565 return rc; 566 } 567 568 rc = driver_register(&monreader_driver); 569 if (rc) 570 goto out_iucv; 571 monreader_device = kzalloc(sizeof(struct device), GFP_KERNEL); 572 if (!monreader_device) 573 goto out_driver; 574 dev_set_name(monreader_device, "monreader-dev"); 575 monreader_device->bus = &iucv_bus; 576 monreader_device->parent = iucv_root; 577 monreader_device->driver = &monreader_driver; 578 monreader_device->release = (void (*)(struct device *))kfree; 579 rc = device_register(monreader_device); 580 if (rc) { 581 put_device(monreader_device); 582 goto out_driver; 583 } 584 585 rc = segment_type(mon_dcss_name); 586 if (rc < 0) { 587 segment_warning(rc, mon_dcss_name); 588 goto out_device; 589 } 590 if (rc != SEG_TYPE_SC) { 591 pr_err("The specified *MONITOR DCSS %s does not have the " 592 "required type SC\n", mon_dcss_name); 593 rc = -EINVAL; 594 goto out_device; 595 } 596 597 rc = segment_load(mon_dcss_name, SEGMENT_SHARED, 598 &mon_dcss_start, &mon_dcss_end); 599 if (rc < 0) { 600 segment_warning(rc, mon_dcss_name); 601 rc = -EINVAL; 602 goto out_device; 603 } 604 dcss_mkname(mon_dcss_name, &user_data_connect[8]); 605 606 /* 607 * misc_register() has to be the last action in module_init(), because 608 * file operations will be available right after this. 609 */ 610 rc = misc_register(&mon_dev); 611 if (rc < 0 ) 612 goto out; 613 return 0; 614 615 out: 616 segment_unload(mon_dcss_name); 617 out_device: 618 device_unregister(monreader_device); 619 out_driver: 620 driver_unregister(&monreader_driver); 621 out_iucv: 622 iucv_unregister(&monreader_iucv_handler, 1); 623 return rc; 624 } 625 626 static void __exit mon_exit(void) 627 { 628 segment_unload(mon_dcss_name); 629 WARN_ON(misc_deregister(&mon_dev) != 0); 630 device_unregister(monreader_device); 631 driver_unregister(&monreader_driver); 632 iucv_unregister(&monreader_iucv_handler, 1); 633 return; 634 } 635 636 637 module_init(mon_init); 638 module_exit(mon_exit); 639 640 module_param_string(mondcss, mon_dcss_name, 9, 0444); 641 MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR " 642 "service, max. 8 chars. Default is MONDCSS"); 643 644 MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>"); 645 MODULE_DESCRIPTION("Character device driver for reading z/VM " 646 "monitor service records."); 647 MODULE_LICENSE("GPL"); 648