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 <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 37static char mon_dcss_name[9] = "MONDCSS\0"; 38 39struct mon_msg { 40 u32 pos; 41 u32 mca_offset; 42 struct iucv_message msg; 43 char msglim_reached; 44 char replied_msglim; 45}; 46 47struct 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 58static unsigned long mon_in_use = 0; 59 60static unsigned long mon_dcss_start; 61static unsigned long mon_dcss_end; 62 63static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue); 64static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue); 65 66static 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 76static 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 81static 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 */ 90static 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 104static inline unsigned long mon_mca_start(struct mon_msg *monmsg) 105{ 106 return *(u32 *) &monmsg->msg.rmmsg; 107} 108 109static inline unsigned long mon_mca_end(struct mon_msg *monmsg) 110{ 111 return *(u32 *) &monmsg->msg.rmmsg[4]; 112} 113 114static 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 119static inline u32 mon_mca_size(struct mon_msg *monmsg) 120{ 121 return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1; 122} 123 124static inline u32 mon_rec_start(struct mon_msg *monmsg) 125{ 126 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4)); 127} 128 129static inline u32 mon_rec_end(struct mon_msg *monmsg) 130{ 131 return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8)); 132} 133 134static 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 149static 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 172static 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 182static 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 201static 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 209static 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 *****************************************************************************/ 233static 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 241static 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 253static 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 269static 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 *****************************************************************************/ 278static 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 rc = -EBUSY; 287 if (test_and_set_bit(MON_IN_USE, &mon_in_use)) 288 goto out; 289 290 rc = -ENOMEM; 291 monpriv = mon_alloc_mem(); 292 if (!monpriv) 293 goto out_use; 294 295 /* 296 * Connect to *MONITOR service 297 */ 298 monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL); 299 if (!monpriv->path) 300 goto out_priv; 301 rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler, 302 MON_SERVICE, NULL, user_data_connect, monpriv); 303 if (rc) { 304 pr_err("Connecting to the z/VM *MONITOR system service " 305 "failed with rc=%i\n", rc); 306 rc = -EIO; 307 goto out_path; 308 } 309 /* 310 * Wait for connection confirmation 311 */ 312 wait_event(mon_conn_wait_queue, 313 atomic_read(&monpriv->iucv_connected) || 314 atomic_read(&monpriv->iucv_severed)); 315 if (atomic_read(&monpriv->iucv_severed)) { 316 atomic_set(&monpriv->iucv_severed, 0); 317 atomic_set(&monpriv->iucv_connected, 0); 318 rc = -EIO; 319 goto out_path; 320 } 321 filp->private_data = monpriv; 322 dev_set_drvdata(monreader_device, monpriv); 323 return nonseekable_open(inode, filp); 324 325out_path: 326 iucv_path_free(monpriv->path); 327out_priv: 328 mon_free_mem(monpriv); 329out_use: 330 clear_bit(MON_IN_USE, &mon_in_use); 331out: 332 return rc; 333} 334 335static int mon_close(struct inode *inode, struct file *filp) 336{ 337 int rc, i; 338 struct mon_private *monpriv = filp->private_data; 339 340 /* 341 * Close IUCV connection and unregister 342 */ 343 if (monpriv->path) { 344 rc = iucv_path_sever(monpriv->path, user_data_sever); 345 if (rc) 346 pr_warning("Disconnecting the z/VM *MONITOR system " 347 "service failed with rc=%i\n", rc); 348 iucv_path_free(monpriv->path); 349 } 350 351 atomic_set(&monpriv->iucv_severed, 0); 352 atomic_set(&monpriv->iucv_connected, 0); 353 atomic_set(&monpriv->read_ready, 0); 354 atomic_set(&monpriv->msglim_count, 0); 355 monpriv->write_index = 0; 356 monpriv->read_index = 0; 357 dev_set_drvdata(monreader_device, NULL); 358 359 for (i = 0; i < MON_MSGLIM; i++) 360 kfree(monpriv->msg_array[i]); 361 kfree(monpriv); 362 clear_bit(MON_IN_USE, &mon_in_use); 363 return 0; 364} 365 366static ssize_t mon_read(struct file *filp, char __user *data, 367 size_t count, loff_t *ppos) 368{ 369 struct mon_private *monpriv = filp->private_data; 370 struct mon_msg *monmsg; 371 int ret; 372 u32 mce_start; 373 374 monmsg = mon_next_message(monpriv); 375 if (IS_ERR(monmsg)) 376 return PTR_ERR(monmsg); 377 378 if (!monmsg) { 379 if (filp->f_flags & O_NONBLOCK) 380 return -EAGAIN; 381 ret = wait_event_interruptible(mon_read_wait_queue, 382 atomic_read(&monpriv->read_ready) || 383 atomic_read(&monpriv->iucv_severed)); 384 if (ret) 385 return ret; 386 if (unlikely(atomic_read(&monpriv->iucv_severed))) 387 return -EIO; 388 monmsg = monpriv->msg_array[monpriv->read_index]; 389 } 390 391 if (!monmsg->pos) 392 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset; 393 if (mon_check_mca(monmsg)) 394 goto reply; 395 396 /* read monitor control element (12 bytes) first */ 397 mce_start = mon_mca_start(monmsg) + monmsg->mca_offset; 398 if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) { 399 count = min(count, (size_t) mce_start + 12 - monmsg->pos); 400 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, 401 count); 402 if (ret) 403 return -EFAULT; 404 monmsg->pos += count; 405 if (monmsg->pos == mce_start + 12) 406 monmsg->pos = mon_rec_start(monmsg); 407 goto out_copy; 408 } 409 410 /* read records */ 411 if (monmsg->pos <= mon_rec_end(monmsg)) { 412 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos 413 + 1); 414 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, 415 count); 416 if (ret) 417 return -EFAULT; 418 monmsg->pos += count; 419 if (monmsg->pos > mon_rec_end(monmsg)) 420 mon_next_mca(monmsg); 421 goto out_copy; 422 } 423reply: 424 ret = mon_send_reply(monmsg, monpriv); 425 return ret; 426 427out_copy: 428 *ppos += count; 429 return count; 430} 431 432static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p) 433{ 434 struct mon_private *monpriv = filp->private_data; 435 436 poll_wait(filp, &mon_read_wait_queue, p); 437 if (unlikely(atomic_read(&monpriv->iucv_severed))) 438 return POLLERR; 439 if (atomic_read(&monpriv->read_ready)) 440 return POLLIN | POLLRDNORM; 441 return 0; 442} 443 444static const struct file_operations mon_fops = { 445 .owner = THIS_MODULE, 446 .open = &mon_open, 447 .release = &mon_close, 448 .read = &mon_read, 449 .poll = &mon_poll, 450}; 451 452static struct miscdevice mon_dev = { 453 .name = "monreader", 454 .fops = &mon_fops, 455 .minor = MISC_DYNAMIC_MINOR, 456}; 457 458 459/****************************************************************************** 460 * suspend / resume * 461 *****************************************************************************/ 462static 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_warning("Disconnecting the z/VM *MONITOR system " 473 "service failed with rc=%i\n", 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 486static 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; 510out_path: 511 rc = -EIO; 512 iucv_path_free(monpriv->path); 513 monpriv->path = NULL; 514out: 515 atomic_set(&monpriv->iucv_severed, 1); 516 return rc; 517} 518 519static 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 533static const struct dev_pm_ops monreader_pm_ops = { 534 .freeze = monreader_freeze, 535 .thaw = monreader_thaw, 536 .restore = monreader_restore, 537}; 538 539static 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 *****************************************************************************/ 549static 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 goto out_driver; 575 dev_set_name(monreader_device, "monreader-dev"); 576 monreader_device->bus = &iucv_bus; 577 monreader_device->parent = iucv_root; 578 monreader_device->driver = &monreader_driver; 579 monreader_device->release = (void (*)(struct device *))kfree; 580 rc = device_register(monreader_device); 581 if (rc) { 582 put_device(monreader_device); 583 goto out_driver; 584 } 585 586 rc = segment_type(mon_dcss_name); 587 if (rc < 0) { 588 segment_warning(rc, mon_dcss_name); 589 goto out_device; 590 } 591 if (rc != SEG_TYPE_SC) { 592 pr_err("The specified *MONITOR DCSS %s does not have the " 593 "required type SC\n", mon_dcss_name); 594 rc = -EINVAL; 595 goto out_device; 596 } 597 598 rc = segment_load(mon_dcss_name, SEGMENT_SHARED, 599 &mon_dcss_start, &mon_dcss_end); 600 if (rc < 0) { 601 segment_warning(rc, mon_dcss_name); 602 rc = -EINVAL; 603 goto out_device; 604 } 605 dcss_mkname(mon_dcss_name, &user_data_connect[8]); 606 607 /* 608 * misc_register() has to be the last action in module_init(), because 609 * file operations will be available right after this. 610 */ 611 rc = misc_register(&mon_dev); 612 if (rc < 0 ) 613 goto out; 614 return 0; 615 616out: 617 segment_unload(mon_dcss_name); 618out_device: 619 device_unregister(monreader_device); 620out_driver: 621 driver_unregister(&monreader_driver); 622out_iucv: 623 iucv_unregister(&monreader_iucv_handler, 1); 624 return rc; 625} 626 627static void __exit mon_exit(void) 628{ 629 segment_unload(mon_dcss_name); 630 misc_deregister(&mon_dev); 631 device_unregister(monreader_device); 632 driver_unregister(&monreader_driver); 633 iucv_unregister(&monreader_iucv_handler, 1); 634 return; 635} 636 637 638module_init(mon_init); 639module_exit(mon_exit); 640 641module_param_string(mondcss, mon_dcss_name, 9, 0444); 642MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR " 643 "service, max. 8 chars. Default is MONDCSS"); 644 645MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>"); 646MODULE_DESCRIPTION("Character device driver for reading z/VM " 647 "monitor service records."); 648MODULE_LICENSE("GPL"); 649