1 /* 2 * Character device driver for reading z/VM *MONITOR service records. 3 * 4 * Copyright IBM Corp. 2004, 2009 5 * 6 * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com> 7 */ 8 9 #define KMSG_COMPONENT "monreader" 10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 11 12 #include <linux/module.h> 13 #include <linux/moduleparam.h> 14 #include <linux/init.h> 15 #include <linux/smp_lock.h> 16 #include <linux/errno.h> 17 #include <linux/types.h> 18 #include <linux/kernel.h> 19 #include <linux/miscdevice.h> 20 #include <linux/ctype.h> 21 #include <linux/spinlock.h> 22 #include <linux/interrupt.h> 23 #include <linux/poll.h> 24 #include <linux/device.h> 25 #include <net/iucv/iucv.h> 26 #include <asm/uaccess.h> 27 #include <asm/ebcdic.h> 28 #include <asm/extmem.h> 29 30 31 #define MON_COLLECT_SAMPLE 0x80 32 #define MON_COLLECT_EVENT 0x40 33 #define MON_SERVICE "*MONITOR" 34 #define MON_IN_USE 0x01 35 #define MON_MSGLIM 255 36 37 static char mon_dcss_name[9] = "MONDCSS\0"; 38 39 struct mon_msg { 40 u32 pos; 41 u32 mca_offset; 42 struct iucv_message msg; 43 char msglim_reached; 44 char replied_msglim; 45 }; 46 47 struct mon_private { 48 struct iucv_path *path; 49 struct mon_msg *msg_array[MON_MSGLIM]; 50 unsigned int write_index; 51 unsigned int read_index; 52 atomic_t msglim_count; 53 atomic_t read_ready; 54 atomic_t iucv_connected; 55 atomic_t iucv_severed; 56 }; 57 58 static unsigned long mon_in_use = 0; 59 60 static unsigned long mon_dcss_start; 61 static unsigned long mon_dcss_end; 62 63 static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue); 64 static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue); 65 66 static u8 user_data_connect[16] = { 67 /* Version code, must be 0x01 for shared mode */ 68 0x01, 69 /* what to collect */ 70 MON_COLLECT_SAMPLE | MON_COLLECT_EVENT, 71 /* DCSS name in EBCDIC, 8 bytes padded with blanks */ 72 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 73 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 74 }; 75 76 static u8 user_data_sever[16] = { 77 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 78 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 79 }; 80 81 static struct device *monreader_device; 82 83 /****************************************************************************** 84 * helper functions * 85 *****************************************************************************/ 86 /* 87 * Create the 8 bytes EBCDIC DCSS segment name from 88 * an ASCII name, incl. padding 89 */ 90 static void dcss_mkname(char *ascii_name, char *ebcdic_name) 91 { 92 int i; 93 94 for (i = 0; i < 8; i++) { 95 if (ascii_name[i] == '\0') 96 break; 97 ebcdic_name[i] = toupper(ascii_name[i]); 98 }; 99 for (; i < 8; i++) 100 ebcdic_name[i] = ' '; 101 ASCEBC(ebcdic_name, 8); 102 } 103 104 static inline unsigned long mon_mca_start(struct mon_msg *monmsg) 105 { 106 return *(u32 *) &monmsg->msg.rmmsg; 107 } 108 109 static inline unsigned long mon_mca_end(struct mon_msg *monmsg) 110 { 111 return *(u32 *) &monmsg->msg.rmmsg[4]; 112 } 113 114 static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index) 115 { 116 return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index); 117 } 118 119 static inline u32 mon_mca_size(struct mon_msg *monmsg) 120 { 121 return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1; 122 } 123 124 static inline u32 mon_rec_start(struct mon_msg *monmsg) 125 { 126 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4)); 127 } 128 129 static inline u32 mon_rec_end(struct mon_msg *monmsg) 130 { 131 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8)); 132 } 133 134 static int mon_check_mca(struct mon_msg *monmsg) 135 { 136 if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) || 137 (mon_rec_start(monmsg) < mon_dcss_start) || 138 (mon_rec_end(monmsg) > mon_dcss_end) || 139 (mon_mca_type(monmsg, 0) == 0) || 140 (mon_mca_size(monmsg) % 12 != 0) || 141 (mon_mca_end(monmsg) <= mon_mca_start(monmsg)) || 142 (mon_mca_end(monmsg) > mon_dcss_end) || 143 (mon_mca_start(monmsg) < mon_dcss_start) || 144 ((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0))) 145 return -EINVAL; 146 return 0; 147 } 148 149 static int mon_send_reply(struct mon_msg *monmsg, 150 struct mon_private *monpriv) 151 { 152 int rc; 153 154 rc = iucv_message_reply(monpriv->path, &monmsg->msg, 155 IUCV_IPRMDATA, NULL, 0); 156 atomic_dec(&monpriv->msglim_count); 157 if (likely(!monmsg->msglim_reached)) { 158 monmsg->pos = 0; 159 monmsg->mca_offset = 0; 160 monpriv->read_index = (monpriv->read_index + 1) % 161 MON_MSGLIM; 162 atomic_dec(&monpriv->read_ready); 163 } else 164 monmsg->replied_msglim = 1; 165 if (rc) { 166 pr_err("Reading monitor data failed with rc=%i\n", rc); 167 return -EIO; 168 } 169 return 0; 170 } 171 172 static void mon_free_mem(struct mon_private *monpriv) 173 { 174 int i; 175 176 for (i = 0; i < MON_MSGLIM; i++) 177 if (monpriv->msg_array[i]) 178 kfree(monpriv->msg_array[i]); 179 kfree(monpriv); 180 } 181 182 static struct mon_private *mon_alloc_mem(void) 183 { 184 int i; 185 struct mon_private *monpriv; 186 187 monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL); 188 if (!monpriv) 189 return NULL; 190 for (i = 0; i < MON_MSGLIM; i++) { 191 monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg), 192 GFP_KERNEL); 193 if (!monpriv->msg_array[i]) { 194 mon_free_mem(monpriv); 195 return NULL; 196 } 197 } 198 return monpriv; 199 } 200 201 static inline void mon_next_mca(struct mon_msg *monmsg) 202 { 203 if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12)) 204 return; 205 monmsg->mca_offset += 12; 206 monmsg->pos = 0; 207 } 208 209 static struct mon_msg *mon_next_message(struct mon_private *monpriv) 210 { 211 struct mon_msg *monmsg; 212 213 if (!atomic_read(&monpriv->read_ready)) 214 return NULL; 215 monmsg = monpriv->msg_array[monpriv->read_index]; 216 if (unlikely(monmsg->replied_msglim)) { 217 monmsg->replied_msglim = 0; 218 monmsg->msglim_reached = 0; 219 monmsg->pos = 0; 220 monmsg->mca_offset = 0; 221 monpriv->read_index = (monpriv->read_index + 1) % 222 MON_MSGLIM; 223 atomic_dec(&monpriv->read_ready); 224 return ERR_PTR(-EOVERFLOW); 225 } 226 return monmsg; 227 } 228 229 230 /****************************************************************************** 231 * IUCV handler * 232 *****************************************************************************/ 233 static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16]) 234 { 235 struct mon_private *monpriv = path->private; 236 237 atomic_set(&monpriv->iucv_connected, 1); 238 wake_up(&mon_conn_wait_queue); 239 } 240 241 static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16]) 242 { 243 struct mon_private *monpriv = path->private; 244 245 pr_err("z/VM *MONITOR system service disconnected with rc=%i\n", 246 ipuser[0]); 247 iucv_path_sever(path, NULL); 248 atomic_set(&monpriv->iucv_severed, 1); 249 wake_up(&mon_conn_wait_queue); 250 wake_up_interruptible(&mon_read_wait_queue); 251 } 252 253 static void mon_iucv_message_pending(struct iucv_path *path, 254 struct iucv_message *msg) 255 { 256 struct mon_private *monpriv = path->private; 257 258 memcpy(&monpriv->msg_array[monpriv->write_index]->msg, 259 msg, sizeof(*msg)); 260 if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) { 261 pr_warning("The read queue for monitor data is full\n"); 262 monpriv->msg_array[monpriv->write_index]->msglim_reached = 1; 263 } 264 monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM; 265 atomic_inc(&monpriv->read_ready); 266 wake_up_interruptible(&mon_read_wait_queue); 267 } 268 269 static struct iucv_handler monreader_iucv_handler = { 270 .path_complete = mon_iucv_path_complete, 271 .path_severed = mon_iucv_path_severed, 272 .message_pending = mon_iucv_message_pending, 273 }; 274 275 /****************************************************************************** 276 * file operations * 277 *****************************************************************************/ 278 static int mon_open(struct inode *inode, struct file *filp) 279 { 280 struct mon_private *monpriv; 281 int rc; 282 283 /* 284 * only one user allowed 285 */ 286 lock_kernel(); 287 rc = -EBUSY; 288 if (test_and_set_bit(MON_IN_USE, &mon_in_use)) 289 goto out; 290 291 rc = -ENOMEM; 292 monpriv = mon_alloc_mem(); 293 if (!monpriv) 294 goto out_use; 295 296 /* 297 * Connect to *MONITOR service 298 */ 299 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL); 300 if (!monpriv->path) 301 goto out_priv; 302 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler, 303 MON_SERVICE, NULL, user_data_connect, monpriv); 304 if (rc) { 305 pr_err("Connecting to the z/VM *MONITOR system service " 306 "failed with rc=%i\n", rc); 307 rc = -EIO; 308 goto out_path; 309 } 310 /* 311 * Wait for connection confirmation 312 */ 313 wait_event(mon_conn_wait_queue, 314 atomic_read(&monpriv->iucv_connected) || 315 atomic_read(&monpriv->iucv_severed)); 316 if (atomic_read(&monpriv->iucv_severed)) { 317 atomic_set(&monpriv->iucv_severed, 0); 318 atomic_set(&monpriv->iucv_connected, 0); 319 rc = -EIO; 320 goto out_path; 321 } 322 filp->private_data = monpriv; 323 dev_set_drvdata(monreader_device, monpriv); 324 unlock_kernel(); 325 return nonseekable_open(inode, filp); 326 327 out_path: 328 iucv_path_free(monpriv->path); 329 out_priv: 330 mon_free_mem(monpriv); 331 out_use: 332 clear_bit(MON_IN_USE, &mon_in_use); 333 out: 334 unlock_kernel(); 335 return rc; 336 } 337 338 static int mon_close(struct inode *inode, struct file *filp) 339 { 340 int rc, i; 341 struct mon_private *monpriv = filp->private_data; 342 343 /* 344 * Close IUCV connection and unregister 345 */ 346 if (monpriv->path) { 347 rc = iucv_path_sever(monpriv->path, user_data_sever); 348 if (rc) 349 pr_warning("Disconnecting the z/VM *MONITOR system " 350 "service failed with rc=%i\n", rc); 351 iucv_path_free(monpriv->path); 352 } 353 354 atomic_set(&monpriv->iucv_severed, 0); 355 atomic_set(&monpriv->iucv_connected, 0); 356 atomic_set(&monpriv->read_ready, 0); 357 atomic_set(&monpriv->msglim_count, 0); 358 monpriv->write_index = 0; 359 monpriv->read_index = 0; 360 361 for (i = 0; i < MON_MSGLIM; i++) 362 kfree(monpriv->msg_array[i]); 363 kfree(monpriv); 364 clear_bit(MON_IN_USE, &mon_in_use); 365 return 0; 366 } 367 368 static ssize_t mon_read(struct file *filp, char __user *data, 369 size_t count, loff_t *ppos) 370 { 371 struct mon_private *monpriv = filp->private_data; 372 struct mon_msg *monmsg; 373 int ret; 374 u32 mce_start; 375 376 monmsg = mon_next_message(monpriv); 377 if (IS_ERR(monmsg)) 378 return PTR_ERR(monmsg); 379 380 if (!monmsg) { 381 if (filp->f_flags & O_NONBLOCK) 382 return -EAGAIN; 383 ret = wait_event_interruptible(mon_read_wait_queue, 384 atomic_read(&monpriv->read_ready) || 385 atomic_read(&monpriv->iucv_severed)); 386 if (ret) 387 return ret; 388 if (unlikely(atomic_read(&monpriv->iucv_severed))) 389 return -EIO; 390 monmsg = monpriv->msg_array[monpriv->read_index]; 391 } 392 393 if (!monmsg->pos) 394 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset; 395 if (mon_check_mca(monmsg)) 396 goto reply; 397 398 /* read monitor control element (12 bytes) first */ 399 mce_start = mon_mca_start(monmsg) + monmsg->mca_offset; 400 if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) { 401 count = min(count, (size_t) mce_start + 12 - monmsg->pos); 402 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, 403 count); 404 if (ret) 405 return -EFAULT; 406 monmsg->pos += count; 407 if (monmsg->pos == mce_start + 12) 408 monmsg->pos = mon_rec_start(monmsg); 409 goto out_copy; 410 } 411 412 /* read records */ 413 if (monmsg->pos <= mon_rec_end(monmsg)) { 414 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos 415 + 1); 416 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, 417 count); 418 if (ret) 419 return -EFAULT; 420 monmsg->pos += count; 421 if (monmsg->pos > mon_rec_end(monmsg)) 422 mon_next_mca(monmsg); 423 goto out_copy; 424 } 425 reply: 426 ret = mon_send_reply(monmsg, monpriv); 427 return ret; 428 429 out_copy: 430 *ppos += count; 431 return count; 432 } 433 434 static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p) 435 { 436 struct mon_private *monpriv = filp->private_data; 437 438 poll_wait(filp, &mon_read_wait_queue, p); 439 if (unlikely(atomic_read(&monpriv->iucv_severed))) 440 return POLLERR; 441 if (atomic_read(&monpriv->read_ready)) 442 return POLLIN | POLLRDNORM; 443 return 0; 444 } 445 446 static const struct file_operations mon_fops = { 447 .owner = THIS_MODULE, 448 .open = &mon_open, 449 .release = &mon_close, 450 .read = &mon_read, 451 .poll = &mon_poll, 452 }; 453 454 static struct miscdevice mon_dev = { 455 .name = "monreader", 456 .fops = &mon_fops, 457 .minor = MISC_DYNAMIC_MINOR, 458 }; 459 460 461 /****************************************************************************** 462 * suspend / resume * 463 *****************************************************************************/ 464 static int monreader_freeze(struct device *dev) 465 { 466 struct mon_private *monpriv = dev_get_drvdata(dev); 467 int rc; 468 469 if (!monpriv) 470 return 0; 471 if (monpriv->path) { 472 rc = iucv_path_sever(monpriv->path, user_data_sever); 473 if (rc) 474 pr_warning("Disconnecting the z/VM *MONITOR system " 475 "service failed with rc=%i\n", rc); 476 iucv_path_free(monpriv->path); 477 } 478 atomic_set(&monpriv->iucv_severed, 0); 479 atomic_set(&monpriv->iucv_connected, 0); 480 atomic_set(&monpriv->read_ready, 0); 481 atomic_set(&monpriv->msglim_count, 0); 482 monpriv->write_index = 0; 483 monpriv->read_index = 0; 484 monpriv->path = NULL; 485 return 0; 486 } 487 488 static int monreader_thaw(struct device *dev) 489 { 490 struct mon_private *monpriv = dev_get_drvdata(dev); 491 int rc; 492 493 if (!monpriv) 494 return 0; 495 rc = -ENOMEM; 496 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL); 497 if (!monpriv->path) 498 goto out; 499 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler, 500 MON_SERVICE, NULL, user_data_connect, monpriv); 501 if (rc) { 502 pr_err("Connecting to the z/VM *MONITOR system service " 503 "failed with rc=%i\n", rc); 504 goto out_path; 505 } 506 wait_event(mon_conn_wait_queue, 507 atomic_read(&monpriv->iucv_connected) || 508 atomic_read(&monpriv->iucv_severed)); 509 if (atomic_read(&monpriv->iucv_severed)) 510 goto out_path; 511 return 0; 512 out_path: 513 rc = -EIO; 514 iucv_path_free(monpriv->path); 515 monpriv->path = NULL; 516 out: 517 atomic_set(&monpriv->iucv_severed, 1); 518 return rc; 519 } 520 521 static int monreader_restore(struct device *dev) 522 { 523 int rc; 524 525 segment_unload(mon_dcss_name); 526 rc = segment_load(mon_dcss_name, SEGMENT_SHARED, 527 &mon_dcss_start, &mon_dcss_end); 528 if (rc < 0) { 529 segment_warning(rc, mon_dcss_name); 530 panic("fatal monreader resume error: no monitor dcss\n"); 531 } 532 return monreader_thaw(dev); 533 } 534 535 static struct dev_pm_ops monreader_pm_ops = { 536 .freeze = monreader_freeze, 537 .thaw = monreader_thaw, 538 .restore = monreader_restore, 539 }; 540 541 static struct device_driver monreader_driver = { 542 .name = "monreader", 543 .bus = &iucv_bus, 544 .pm = &monreader_pm_ops, 545 }; 546 547 548 /****************************************************************************** 549 * module init/exit * 550 *****************************************************************************/ 551 static int __init mon_init(void) 552 { 553 int rc; 554 555 if (!MACHINE_IS_VM) { 556 pr_err("The z/VM *MONITOR record device driver cannot be " 557 "loaded without z/VM\n"); 558 return -ENODEV; 559 } 560 561 /* 562 * Register with IUCV and connect to *MONITOR service 563 */ 564 rc = iucv_register(&monreader_iucv_handler, 1); 565 if (rc) { 566 pr_err("The z/VM *MONITOR record device driver failed to " 567 "register with IUCV\n"); 568 return rc; 569 } 570 571 rc = driver_register(&monreader_driver); 572 if (rc) 573 goto out_iucv; 574 monreader_device = kzalloc(sizeof(struct device), GFP_KERNEL); 575 if (!monreader_device) 576 goto out_driver; 577 dev_set_name(monreader_device, "monreader-dev"); 578 monreader_device->bus = &iucv_bus; 579 monreader_device->parent = iucv_root; 580 monreader_device->driver = &monreader_driver; 581 monreader_device->release = (void (*)(struct device *))kfree; 582 rc = device_register(monreader_device); 583 if (rc) { 584 put_device(monreader_device); 585 goto out_driver; 586 } 587 588 rc = segment_type(mon_dcss_name); 589 if (rc < 0) { 590 segment_warning(rc, mon_dcss_name); 591 goto out_device; 592 } 593 if (rc != SEG_TYPE_SC) { 594 pr_err("The specified *MONITOR DCSS %s does not have the " 595 "required type SC\n", mon_dcss_name); 596 rc = -EINVAL; 597 goto out_device; 598 } 599 600 rc = segment_load(mon_dcss_name, SEGMENT_SHARED, 601 &mon_dcss_start, &mon_dcss_end); 602 if (rc < 0) { 603 segment_warning(rc, mon_dcss_name); 604 rc = -EINVAL; 605 goto out_device; 606 } 607 dcss_mkname(mon_dcss_name, &user_data_connect[8]); 608 609 rc = misc_register(&mon_dev); 610 if (rc < 0 ) 611 goto out; 612 return 0; 613 614 out: 615 segment_unload(mon_dcss_name); 616 out_device: 617 device_unregister(monreader_device); 618 out_driver: 619 driver_unregister(&monreader_driver); 620 out_iucv: 621 iucv_unregister(&monreader_iucv_handler, 1); 622 return rc; 623 } 624 625 static void __exit mon_exit(void) 626 { 627 segment_unload(mon_dcss_name); 628 WARN_ON(misc_deregister(&mon_dev) != 0); 629 device_unregister(monreader_device); 630 driver_unregister(&monreader_driver); 631 iucv_unregister(&monreader_iucv_handler, 1); 632 return; 633 } 634 635 636 module_init(mon_init); 637 module_exit(mon_exit); 638 639 module_param_string(mondcss, mon_dcss_name, 9, 0444); 640 MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR " 641 "service, max. 8 chars. Default is MONDCSS"); 642 643 MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>"); 644 MODULE_DESCRIPTION("Character device driver for reading z/VM " 645 "monitor service records."); 646 MODULE_LICENSE("GPL"); 647