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 <linux/slab.h> 25 #include <net/iucv/iucv.h> 26 #include <linux/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 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) 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) 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_warn("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_warn("Disconnecting the z/VM *MONITOR system service failed with rc=%i\n", 346 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 __poll_t 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 .llseek = noop_llseek, 450 }; 451 452 static struct miscdevice mon_dev = { 453 .name = "monreader", 454 .fops = &mon_fops, 455 .minor = MISC_DYNAMIC_MINOR, 456 }; 457 458 459 /****************************************************************************** 460 * suspend / resume * 461 *****************************************************************************/ 462 static int monreader_freeze(struct device *dev) 463 { 464 struct mon_private *monpriv = dev_get_drvdata(dev); 465 int rc; 466 467 if (!monpriv) 468 return 0; 469 if (monpriv->path) { 470 rc = iucv_path_sever(monpriv->path, user_data_sever); 471 if (rc) 472 pr_warn("Disconnecting the z/VM *MONITOR system service failed with rc=%i\n", 473 rc); 474 iucv_path_free(monpriv->path); 475 } 476 atomic_set(&monpriv->iucv_severed, 0); 477 atomic_set(&monpriv->iucv_connected, 0); 478 atomic_set(&monpriv->read_ready, 0); 479 atomic_set(&monpriv->msglim_count, 0); 480 monpriv->write_index = 0; 481 monpriv->read_index = 0; 482 monpriv->path = NULL; 483 return 0; 484 } 485 486 static int monreader_thaw(struct device *dev) 487 { 488 struct mon_private *monpriv = dev_get_drvdata(dev); 489 int rc; 490 491 if (!monpriv) 492 return 0; 493 rc = -ENOMEM; 494 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL); 495 if (!monpriv->path) 496 goto out; 497 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler, 498 MON_SERVICE, NULL, user_data_connect, monpriv); 499 if (rc) { 500 pr_err("Connecting to the z/VM *MONITOR system service " 501 "failed with rc=%i\n", rc); 502 goto out_path; 503 } 504 wait_event(mon_conn_wait_queue, 505 atomic_read(&monpriv->iucv_connected) || 506 atomic_read(&monpriv->iucv_severed)); 507 if (atomic_read(&monpriv->iucv_severed)) 508 goto out_path; 509 return 0; 510 out_path: 511 rc = -EIO; 512 iucv_path_free(monpriv->path); 513 monpriv->path = NULL; 514 out: 515 atomic_set(&monpriv->iucv_severed, 1); 516 return rc; 517 } 518 519 static int monreader_restore(struct device *dev) 520 { 521 int rc; 522 523 segment_unload(mon_dcss_name); 524 rc = segment_load(mon_dcss_name, SEGMENT_SHARED, 525 &mon_dcss_start, &mon_dcss_end); 526 if (rc < 0) { 527 segment_warning(rc, mon_dcss_name); 528 panic("fatal monreader resume error: no monitor dcss\n"); 529 } 530 return monreader_thaw(dev); 531 } 532 533 static const struct dev_pm_ops monreader_pm_ops = { 534 .freeze = monreader_freeze, 535 .thaw = monreader_thaw, 536 .restore = monreader_restore, 537 }; 538 539 static struct device_driver monreader_driver = { 540 .name = "monreader", 541 .bus = &iucv_bus, 542 .pm = &monreader_pm_ops, 543 }; 544 545 546 /****************************************************************************** 547 * module init/exit * 548 *****************************************************************************/ 549 static int __init mon_init(void) 550 { 551 int rc; 552 553 if (!MACHINE_IS_VM) { 554 pr_err("The z/VM *MONITOR record device driver cannot be " 555 "loaded without z/VM\n"); 556 return -ENODEV; 557 } 558 559 /* 560 * Register with IUCV and connect to *MONITOR service 561 */ 562 rc = iucv_register(&monreader_iucv_handler, 1); 563 if (rc) { 564 pr_err("The z/VM *MONITOR record device driver failed to " 565 "register with IUCV\n"); 566 return rc; 567 } 568 569 rc = driver_register(&monreader_driver); 570 if (rc) 571 goto out_iucv; 572 monreader_device = kzalloc(sizeof(struct device), GFP_KERNEL); 573 if (!monreader_device) { 574 rc = -ENOMEM; 575 goto out_driver; 576 } 577 578 dev_set_name(monreader_device, "monreader-dev"); 579 monreader_device->bus = &iucv_bus; 580 monreader_device->parent = iucv_root; 581 monreader_device->driver = &monreader_driver; 582 monreader_device->release = (void (*)(struct device *))kfree; 583 rc = device_register(monreader_device); 584 if (rc) { 585 put_device(monreader_device); 586 goto out_driver; 587 } 588 589 rc = segment_type(mon_dcss_name); 590 if (rc < 0) { 591 segment_warning(rc, mon_dcss_name); 592 goto out_device; 593 } 594 if (rc != SEG_TYPE_SC) { 595 pr_err("The specified *MONITOR DCSS %s does not have the " 596 "required type SC\n", mon_dcss_name); 597 rc = -EINVAL; 598 goto out_device; 599 } 600 601 rc = segment_load(mon_dcss_name, SEGMENT_SHARED, 602 &mon_dcss_start, &mon_dcss_end); 603 if (rc < 0) { 604 segment_warning(rc, mon_dcss_name); 605 rc = -EINVAL; 606 goto out_device; 607 } 608 dcss_mkname(mon_dcss_name, &user_data_connect[8]); 609 610 /* 611 * misc_register() has to be the last action in module_init(), because 612 * file operations will be available right after this. 613 */ 614 rc = misc_register(&mon_dev); 615 if (rc < 0 ) 616 goto out; 617 return 0; 618 619 out: 620 segment_unload(mon_dcss_name); 621 out_device: 622 device_unregister(monreader_device); 623 out_driver: 624 driver_unregister(&monreader_driver); 625 out_iucv: 626 iucv_unregister(&monreader_iucv_handler, 1); 627 return rc; 628 } 629 630 static void __exit mon_exit(void) 631 { 632 segment_unload(mon_dcss_name); 633 misc_deregister(&mon_dev); 634 device_unregister(monreader_device); 635 driver_unregister(&monreader_driver); 636 iucv_unregister(&monreader_iucv_handler, 1); 637 return; 638 } 639 640 641 module_init(mon_init); 642 module_exit(mon_exit); 643 644 module_param_string(mondcss, mon_dcss_name, 9, 0444); 645 MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR " 646 "service, max. 8 chars. Default is MONDCSS"); 647 648 MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>"); 649 MODULE_DESCRIPTION("Character device driver for reading z/VM " 650 "monitor service records."); 651 MODULE_LICENSE("GPL"); 652