1 /* 2 * drivers/s390/char/monreader.c 3 * 4 * Character device driver for reading z/VM *MONITOR service records. 5 * 6 * Copyright IBM Corp. 2004, 2008 7 * Author: Gerald Schaefer <gerald.schaefer@de.ibm.com> 8 */ 9 10 #define KMSG_COMPONENT "monreader" 11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 12 13 #include <linux/module.h> 14 #include <linux/moduleparam.h> 15 #include <linux/init.h> 16 #include <linux/smp_lock.h> 17 #include <linux/errno.h> 18 #include <linux/types.h> 19 #include <linux/kernel.h> 20 #include <linux/miscdevice.h> 21 #include <linux/ctype.h> 22 #include <linux/spinlock.h> 23 #include <linux/interrupt.h> 24 #include <linux/poll.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 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 lock_kernel(); 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 unlock_kernel(); 323 return nonseekable_open(inode, filp); 324 325 out_path: 326 kfree(monpriv->path); 327 out_priv: 328 mon_free_mem(monpriv); 329 out_use: 330 clear_bit(MON_IN_USE, &mon_in_use); 331 out: 332 unlock_kernel(); 333 return rc; 334 } 335 336 static int mon_close(struct inode *inode, struct file *filp) 337 { 338 int rc, i; 339 struct mon_private *monpriv = filp->private_data; 340 341 /* 342 * Close IUCV connection and unregister 343 */ 344 rc = iucv_path_sever(monpriv->path, user_data_sever); 345 if (rc) 346 pr_warning("Disconnecting the z/VM *MONITOR system service " 347 "failed with rc=%i\n", rc); 348 349 atomic_set(&monpriv->iucv_severed, 0); 350 atomic_set(&monpriv->iucv_connected, 0); 351 atomic_set(&monpriv->read_ready, 0); 352 atomic_set(&monpriv->msglim_count, 0); 353 monpriv->write_index = 0; 354 monpriv->read_index = 0; 355 356 for (i = 0; i < MON_MSGLIM; i++) 357 kfree(monpriv->msg_array[i]); 358 kfree(monpriv); 359 clear_bit(MON_IN_USE, &mon_in_use); 360 return 0; 361 } 362 363 static ssize_t mon_read(struct file *filp, char __user *data, 364 size_t count, loff_t *ppos) 365 { 366 struct mon_private *monpriv = filp->private_data; 367 struct mon_msg *monmsg; 368 int ret; 369 u32 mce_start; 370 371 monmsg = mon_next_message(monpriv); 372 if (IS_ERR(monmsg)) 373 return PTR_ERR(monmsg); 374 375 if (!monmsg) { 376 if (filp->f_flags & O_NONBLOCK) 377 return -EAGAIN; 378 ret = wait_event_interruptible(mon_read_wait_queue, 379 atomic_read(&monpriv->read_ready) || 380 atomic_read(&monpriv->iucv_severed)); 381 if (ret) 382 return ret; 383 if (unlikely(atomic_read(&monpriv->iucv_severed))) 384 return -EIO; 385 monmsg = monpriv->msg_array[monpriv->read_index]; 386 } 387 388 if (!monmsg->pos) 389 monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset; 390 if (mon_check_mca(monmsg)) 391 goto reply; 392 393 /* read monitor control element (12 bytes) first */ 394 mce_start = mon_mca_start(monmsg) + monmsg->mca_offset; 395 if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) { 396 count = min(count, (size_t) mce_start + 12 - monmsg->pos); 397 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, 398 count); 399 if (ret) 400 return -EFAULT; 401 monmsg->pos += count; 402 if (monmsg->pos == mce_start + 12) 403 monmsg->pos = mon_rec_start(monmsg); 404 goto out_copy; 405 } 406 407 /* read records */ 408 if (monmsg->pos <= mon_rec_end(monmsg)) { 409 count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos 410 + 1); 411 ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos, 412 count); 413 if (ret) 414 return -EFAULT; 415 monmsg->pos += count; 416 if (monmsg->pos > mon_rec_end(monmsg)) 417 mon_next_mca(monmsg); 418 goto out_copy; 419 } 420 reply: 421 ret = mon_send_reply(monmsg, monpriv); 422 return ret; 423 424 out_copy: 425 *ppos += count; 426 return count; 427 } 428 429 static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p) 430 { 431 struct mon_private *monpriv = filp->private_data; 432 433 poll_wait(filp, &mon_read_wait_queue, p); 434 if (unlikely(atomic_read(&monpriv->iucv_severed))) 435 return POLLERR; 436 if (atomic_read(&monpriv->read_ready)) 437 return POLLIN | POLLRDNORM; 438 return 0; 439 } 440 441 static const struct file_operations mon_fops = { 442 .owner = THIS_MODULE, 443 .open = &mon_open, 444 .release = &mon_close, 445 .read = &mon_read, 446 .poll = &mon_poll, 447 }; 448 449 static struct miscdevice mon_dev = { 450 .name = "monreader", 451 .fops = &mon_fops, 452 .minor = MISC_DYNAMIC_MINOR, 453 }; 454 455 /****************************************************************************** 456 * module init/exit * 457 *****************************************************************************/ 458 static int __init mon_init(void) 459 { 460 int rc; 461 462 if (!MACHINE_IS_VM) { 463 pr_err("The z/VM *MONITOR record device driver cannot be " 464 "loaded without z/VM\n"); 465 return -ENODEV; 466 } 467 468 /* 469 * Register with IUCV and connect to *MONITOR service 470 */ 471 rc = iucv_register(&monreader_iucv_handler, 1); 472 if (rc) { 473 pr_err("The z/VM *MONITOR record device driver failed to " 474 "register with IUCV\n"); 475 return rc; 476 } 477 478 rc = segment_type(mon_dcss_name); 479 if (rc < 0) { 480 segment_warning(rc, mon_dcss_name); 481 goto out_iucv; 482 } 483 if (rc != SEG_TYPE_SC) { 484 pr_err("The specified *MONITOR DCSS %s does not have the " 485 "required type SC\n", mon_dcss_name); 486 rc = -EINVAL; 487 goto out_iucv; 488 } 489 490 rc = segment_load(mon_dcss_name, SEGMENT_SHARED, 491 &mon_dcss_start, &mon_dcss_end); 492 if (rc < 0) { 493 segment_warning(rc, mon_dcss_name); 494 rc = -EINVAL; 495 goto out_iucv; 496 } 497 dcss_mkname(mon_dcss_name, &user_data_connect[8]); 498 499 rc = misc_register(&mon_dev); 500 if (rc < 0 ) 501 goto out; 502 return 0; 503 504 out: 505 segment_unload(mon_dcss_name); 506 out_iucv: 507 iucv_unregister(&monreader_iucv_handler, 1); 508 return rc; 509 } 510 511 static void __exit mon_exit(void) 512 { 513 segment_unload(mon_dcss_name); 514 WARN_ON(misc_deregister(&mon_dev) != 0); 515 iucv_unregister(&monreader_iucv_handler, 1); 516 return; 517 } 518 519 520 module_init(mon_init); 521 module_exit(mon_exit); 522 523 module_param_string(mondcss, mon_dcss_name, 9, 0444); 524 MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR " 525 "service, max. 8 chars. Default is MONDCSS"); 526 527 MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>"); 528 MODULE_DESCRIPTION("Character device driver for reading z/VM " 529 "monitor service records."); 530 MODULE_LICENSE("GPL"); 531