1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * SCLP Store Data support and sysfs interface 4 * 5 * Copyright IBM Corp. 2017 6 */ 7 8 #define KMSG_COMPONENT "sclp_sd" 9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 10 11 #include <linux/completion.h> 12 #include <linux/kobject.h> 13 #include <linux/list.h> 14 #include <linux/printk.h> 15 #include <linux/slab.h> 16 #include <linux/vmalloc.h> 17 #include <linux/async.h> 18 #include <linux/export.h> 19 #include <linux/mutex.h> 20 21 #include <asm/pgalloc.h> 22 23 #include "sclp.h" 24 25 #define SD_EQ_STORE_DATA 0 26 #define SD_EQ_HALT 1 27 #define SD_EQ_SIZE 2 28 29 #define SD_DI_CONFIG 3 30 31 struct sclp_sd_evbuf { 32 struct evbuf_header hdr; 33 u8 eq; 34 u8 di; 35 u8 rflags; 36 u64 :56; 37 u32 id; 38 u16 :16; 39 u8 fmt; 40 u8 status; 41 u64 sat; 42 u64 sa; 43 u32 esize; 44 u32 dsize; 45 } __packed; 46 47 struct sclp_sd_sccb { 48 struct sccb_header hdr; 49 struct sclp_sd_evbuf evbuf; 50 } __packed __aligned(PAGE_SIZE); 51 52 /** 53 * struct sclp_sd_data - Result of a Store Data request 54 * @esize_bytes: Resulting esize in bytes 55 * @dsize_bytes: Resulting dsize in bytes 56 * @data: Pointer to data - must be released using vfree() 57 */ 58 struct sclp_sd_data { 59 size_t esize_bytes; 60 size_t dsize_bytes; 61 void *data; 62 }; 63 64 /** 65 * struct sclp_sd_listener - Listener for asynchronous Store Data response 66 * @list: For enqueueing this struct 67 * @id: Event ID of response to listen for 68 * @completion: Can be used to wait for response 69 * @evbuf: Contains the resulting Store Data response after completion 70 */ 71 struct sclp_sd_listener { 72 struct list_head list; 73 u32 id; 74 struct completion completion; 75 struct sclp_sd_evbuf evbuf; 76 }; 77 78 /** 79 * struct sclp_sd_file - Sysfs representation of a Store Data entity 80 * @kobj: Kobject 81 * @data_attr: Attribute for accessing data contents 82 * @data_mutex: Mutex to serialize access and updates to @data 83 * @data: Data associated with this entity 84 * @di: DI value associated with this entity 85 */ 86 struct sclp_sd_file { 87 struct kobject kobj; 88 struct bin_attribute data_attr; 89 struct mutex data_mutex; 90 struct sclp_sd_data data; 91 u8 di; 92 }; 93 #define to_sd_file(x) container_of(x, struct sclp_sd_file, kobj) 94 95 static struct kset *sclp_sd_kset; 96 static struct sclp_sd_file *config_file; 97 98 static LIST_HEAD(sclp_sd_queue); 99 static DEFINE_SPINLOCK(sclp_sd_queue_lock); 100 101 /** 102 * sclp_sd_listener_add() - Add listener for Store Data responses 103 * @listener: Listener to add 104 */ 105 static void sclp_sd_listener_add(struct sclp_sd_listener *listener) 106 { 107 spin_lock_irq(&sclp_sd_queue_lock); 108 list_add_tail(&listener->list, &sclp_sd_queue); 109 spin_unlock_irq(&sclp_sd_queue_lock); 110 } 111 112 /** 113 * sclp_sd_listener_remove() - Remove listener for Store Data responses 114 * @listener: Listener to remove 115 */ 116 static void sclp_sd_listener_remove(struct sclp_sd_listener *listener) 117 { 118 spin_lock_irq(&sclp_sd_queue_lock); 119 list_del(&listener->list); 120 spin_unlock_irq(&sclp_sd_queue_lock); 121 } 122 123 /** 124 * sclp_sd_listener_init() - Initialize a Store Data response listener 125 * @listener: Response listener to initialize 126 * @id: Event ID to listen for 127 * 128 * Initialize a listener for asynchronous Store Data responses. This listener 129 * can afterwards be used to wait for a specific response and to retrieve 130 * the associated response data. 131 */ 132 static void sclp_sd_listener_init(struct sclp_sd_listener *listener, u32 id) 133 { 134 memset(listener, 0, sizeof(*listener)); 135 listener->id = id; 136 init_completion(&listener->completion); 137 } 138 139 /** 140 * sclp_sd_receiver() - Receiver for Store Data events 141 * @evbuf_hdr: Header of received events 142 * 143 * Process Store Data events and complete listeners with matching event IDs. 144 */ 145 static void sclp_sd_receiver(struct evbuf_header *evbuf_hdr) 146 { 147 struct sclp_sd_evbuf *evbuf = (struct sclp_sd_evbuf *) evbuf_hdr; 148 struct sclp_sd_listener *listener; 149 int found = 0; 150 151 pr_debug("received event (id=0x%08x)\n", evbuf->id); 152 spin_lock(&sclp_sd_queue_lock); 153 list_for_each_entry(listener, &sclp_sd_queue, list) { 154 if (listener->id != evbuf->id) 155 continue; 156 157 listener->evbuf = *evbuf; 158 complete(&listener->completion); 159 found = 1; 160 break; 161 } 162 spin_unlock(&sclp_sd_queue_lock); 163 164 if (!found) 165 pr_debug("unsolicited event (id=0x%08x)\n", evbuf->id); 166 } 167 168 static struct sclp_register sclp_sd_register = { 169 .send_mask = EVTYP_STORE_DATA_MASK, 170 .receive_mask = EVTYP_STORE_DATA_MASK, 171 .receiver_fn = sclp_sd_receiver, 172 }; 173 174 /** 175 * sclp_sd_sync() - Perform Store Data request synchronously 176 * @page: Address of work page - must be below 2GB 177 * @eq: Input EQ value 178 * @di: Input DI value 179 * @sat: Input SAT value 180 * @sa: Input SA value used to specify the address of the target buffer 181 * @dsize_ptr: Optional pointer to input and output DSIZE value 182 * @esize_ptr: Optional pointer to output ESIZE value 183 * 184 * Perform Store Data request with specified parameters and wait for completion. 185 * 186 * Return %0 on success and store resulting DSIZE and ESIZE values in 187 * @dsize_ptr and @esize_ptr (if provided). Return non-zero on error. 188 */ 189 static int sclp_sd_sync(unsigned long page, u8 eq, u8 di, u64 sat, u64 sa, 190 u32 *dsize_ptr, u32 *esize_ptr) 191 { 192 struct sclp_sd_sccb *sccb = (void *) page; 193 struct sclp_sd_listener listener; 194 struct sclp_sd_evbuf *evbuf; 195 int rc; 196 197 sclp_sd_listener_init(&listener, __pa(sccb)); 198 sclp_sd_listener_add(&listener); 199 200 /* Prepare SCCB */ 201 memset(sccb, 0, PAGE_SIZE); 202 sccb->hdr.length = sizeof(sccb->hdr) + sizeof(sccb->evbuf); 203 evbuf = &sccb->evbuf; 204 evbuf->hdr.length = sizeof(*evbuf); 205 evbuf->hdr.type = EVTYP_STORE_DATA; 206 evbuf->eq = eq; 207 evbuf->di = di; 208 evbuf->id = listener.id; 209 evbuf->fmt = 1; 210 evbuf->sat = sat; 211 evbuf->sa = sa; 212 if (dsize_ptr) 213 evbuf->dsize = *dsize_ptr; 214 215 /* Perform command */ 216 pr_debug("request (eq=%d, di=%d, id=0x%08x)\n", eq, di, listener.id); 217 rc = sclp_sync_request(SCLP_CMDW_WRITE_EVENT_DATA, sccb); 218 pr_debug("request done (rc=%d)\n", rc); 219 if (rc) 220 goto out; 221 222 /* Evaluate response */ 223 if (sccb->hdr.response_code == 0x73f0) { 224 pr_debug("event not supported\n"); 225 rc = -EIO; 226 goto out_remove; 227 } 228 if (sccb->hdr.response_code != 0x0020 || !(evbuf->hdr.flags & 0x80)) { 229 rc = -EIO; 230 goto out; 231 } 232 if (!(evbuf->rflags & 0x80)) { 233 rc = wait_for_completion_interruptible(&listener.completion); 234 if (rc) 235 goto out; 236 evbuf = &listener.evbuf; 237 } 238 switch (evbuf->status) { 239 case 0: 240 if (dsize_ptr) 241 *dsize_ptr = evbuf->dsize; 242 if (esize_ptr) 243 *esize_ptr = evbuf->esize; 244 pr_debug("success (dsize=%u, esize=%u)\n", evbuf->dsize, 245 evbuf->esize); 246 break; 247 case 3: 248 rc = -ENOENT; 249 break; 250 default: 251 rc = -EIO; 252 break; 253 254 } 255 256 out: 257 if (rc && rc != -ENOENT) { 258 /* Provide some information about what went wrong */ 259 pr_warn("Store Data request failed (eq=%d, di=%d, " 260 "response=0x%04x, flags=0x%02x, status=%d, rc=%d)\n", 261 eq, di, sccb->hdr.response_code, evbuf->hdr.flags, 262 evbuf->status, rc); 263 } 264 265 out_remove: 266 sclp_sd_listener_remove(&listener); 267 268 return rc; 269 } 270 271 /** 272 * sclp_sd_store_data() - Obtain data for specified Store Data entity 273 * @result: Resulting data 274 * @di: DI value associated with this entity 275 * 276 * Perform a series of Store Data requests to obtain the size and contents of 277 * the specified Store Data entity. 278 * 279 * Return: 280 * %0: Success - result is stored in @result. @result->data must be 281 * released using vfree() after use. 282 * %-ENOENT: No data available for this entity 283 * %<0: Other error 284 */ 285 static int sclp_sd_store_data(struct sclp_sd_data *result, u8 di) 286 { 287 u32 dsize = 0, esize = 0; 288 unsigned long page, asce = 0; 289 void *data = NULL; 290 int rc; 291 292 page = __get_free_page(GFP_KERNEL | GFP_DMA); 293 if (!page) 294 return -ENOMEM; 295 296 /* Get size */ 297 rc = sclp_sd_sync(page, SD_EQ_SIZE, di, 0, 0, &dsize, &esize); 298 if (rc) 299 goto out; 300 if (dsize == 0) 301 goto out_result; 302 303 /* Allocate memory */ 304 data = vzalloc(array_size((size_t)dsize, PAGE_SIZE)); 305 if (!data) { 306 rc = -ENOMEM; 307 goto out; 308 } 309 310 /* Get translation table for buffer */ 311 asce = base_asce_alloc((unsigned long) data, dsize); 312 if (!asce) { 313 vfree(data); 314 rc = -ENOMEM; 315 goto out; 316 } 317 318 /* Get data */ 319 rc = sclp_sd_sync(page, SD_EQ_STORE_DATA, di, asce, (u64) data, &dsize, 320 &esize); 321 if (rc) { 322 /* Cancel running request if interrupted */ 323 if (rc == -ERESTARTSYS) { 324 if (sclp_sd_sync(page, SD_EQ_HALT, di, 0, 0, NULL, NULL)) { 325 pr_warn("Could not stop Store Data request - leaking at least %zu bytes\n", 326 (size_t)dsize * PAGE_SIZE); 327 data = NULL; 328 asce = 0; 329 } 330 } 331 vfree(data); 332 goto out; 333 } 334 335 out_result: 336 result->esize_bytes = (size_t) esize * PAGE_SIZE; 337 result->dsize_bytes = (size_t) dsize * PAGE_SIZE; 338 result->data = data; 339 340 out: 341 base_asce_free(asce); 342 free_page(page); 343 344 return rc; 345 } 346 347 /** 348 * sclp_sd_data_reset() - Reset Store Data result buffer 349 * @data: Data buffer to reset 350 * 351 * Reset @data to initial state and release associated memory. 352 */ 353 static void sclp_sd_data_reset(struct sclp_sd_data *data) 354 { 355 vfree(data->data); 356 data->data = NULL; 357 data->dsize_bytes = 0; 358 data->esize_bytes = 0; 359 } 360 361 /** 362 * sclp_sd_file_release() - Release function for sclp_sd_file object 363 * @kobj: Kobject embedded in sclp_sd_file object 364 */ 365 static void sclp_sd_file_release(struct kobject *kobj) 366 { 367 struct sclp_sd_file *sd_file = to_sd_file(kobj); 368 369 sclp_sd_data_reset(&sd_file->data); 370 kfree(sd_file); 371 } 372 373 /** 374 * sclp_sd_file_update() - Update contents of sclp_sd_file object 375 * @sd_file: Object to update 376 * 377 * Obtain the current version of data associated with the Store Data entity 378 * @sd_file. 379 * 380 * On success, return %0 and generate a KOBJ_CHANGE event to indicate that the 381 * data may have changed. Return non-zero otherwise. 382 */ 383 static int sclp_sd_file_update(struct sclp_sd_file *sd_file) 384 { 385 const char *name = kobject_name(&sd_file->kobj); 386 struct sclp_sd_data data; 387 int rc; 388 389 rc = sclp_sd_store_data(&data, sd_file->di); 390 if (rc) { 391 if (rc == -ENOENT) { 392 pr_info("No data is available for the %s data entity\n", 393 name); 394 } 395 return rc; 396 } 397 398 mutex_lock(&sd_file->data_mutex); 399 sclp_sd_data_reset(&sd_file->data); 400 sd_file->data = data; 401 mutex_unlock(&sd_file->data_mutex); 402 403 pr_info("A %zu-byte %s data entity was retrieved\n", data.dsize_bytes, 404 name); 405 kobject_uevent(&sd_file->kobj, KOBJ_CHANGE); 406 407 return 0; 408 } 409 410 /** 411 * sclp_sd_file_update_async() - Wrapper for asynchronous update call 412 * @data: Object to update 413 * @cookie: Unused 414 */ 415 static void sclp_sd_file_update_async(void *data, async_cookie_t cookie) 416 { 417 struct sclp_sd_file *sd_file = data; 418 419 sclp_sd_file_update(sd_file); 420 } 421 422 /** 423 * reload_store() - Store function for "reload" sysfs attribute 424 * @kobj: Kobject of sclp_sd_file object 425 * @attr: Reload attribute 426 * @buf: Data written to sysfs attribute 427 * @count: Count of bytes written 428 * 429 * Initiate a reload of the data associated with an sclp_sd_file object. 430 */ 431 static ssize_t reload_store(struct kobject *kobj, struct kobj_attribute *attr, 432 const char *buf, size_t count) 433 { 434 struct sclp_sd_file *sd_file = to_sd_file(kobj); 435 436 sclp_sd_file_update(sd_file); 437 438 return count; 439 } 440 441 static struct kobj_attribute reload_attr = __ATTR_WO(reload); 442 443 static struct attribute *sclp_sd_file_default_attrs[] = { 444 &reload_attr.attr, 445 NULL, 446 }; 447 ATTRIBUTE_GROUPS(sclp_sd_file_default); 448 449 static struct kobj_type sclp_sd_file_ktype = { 450 .sysfs_ops = &kobj_sysfs_ops, 451 .release = sclp_sd_file_release, 452 .default_groups = sclp_sd_file_default_groups, 453 }; 454 455 /** 456 * data_read() - Read function for "data" sysfs attribute 457 * @file: Open file pointer 458 * @kobj: Kobject of sclp_sd_file object 459 * @attr: Data attribute 460 * @buffer: Target buffer 461 * @off: Requested file offset 462 * @size: Requested number of bytes 463 * 464 * Store the requested portion of the Store Data entity contents into the 465 * specified buffer. Return the number of bytes stored on success, or %0 466 * on EOF. 467 */ 468 static ssize_t data_read(struct file *file, struct kobject *kobj, 469 struct bin_attribute *attr, char *buffer, 470 loff_t off, size_t size) 471 { 472 struct sclp_sd_file *sd_file = to_sd_file(kobj); 473 size_t data_size; 474 char *data; 475 476 mutex_lock(&sd_file->data_mutex); 477 478 data = sd_file->data.data; 479 data_size = sd_file->data.dsize_bytes; 480 if (!data || off >= data_size) { 481 size = 0; 482 } else { 483 if (off + size > data_size) 484 size = data_size - off; 485 memcpy(buffer, data + off, size); 486 } 487 488 mutex_unlock(&sd_file->data_mutex); 489 490 return size; 491 } 492 493 /** 494 * sclp_sd_file_create() - Add a sysfs file representing a Store Data entity 495 * @name: Name of file 496 * @di: DI value associated with this entity 497 * 498 * Create a sysfs directory with the given @name located under 499 * 500 * /sys/firmware/sclp_sd/ 501 * 502 * The files in this directory can be used to access the contents of the Store 503 * Data entity associated with @DI. 504 * 505 * Return pointer to resulting sclp_sd_file object on success, %NULL otherwise. 506 * The object must be freed by calling kobject_put() on the embedded kobject 507 * pointer after use. 508 */ 509 static __init struct sclp_sd_file *sclp_sd_file_create(const char *name, u8 di) 510 { 511 struct sclp_sd_file *sd_file; 512 int rc; 513 514 sd_file = kzalloc(sizeof(*sd_file), GFP_KERNEL); 515 if (!sd_file) 516 return NULL; 517 sd_file->di = di; 518 mutex_init(&sd_file->data_mutex); 519 520 /* Create kobject located under /sys/firmware/sclp_sd/ */ 521 sd_file->kobj.kset = sclp_sd_kset; 522 rc = kobject_init_and_add(&sd_file->kobj, &sclp_sd_file_ktype, NULL, 523 "%s", name); 524 if (rc) { 525 kobject_put(&sd_file->kobj); 526 return NULL; 527 } 528 529 sysfs_bin_attr_init(&sd_file->data_attr); 530 sd_file->data_attr.attr.name = "data"; 531 sd_file->data_attr.attr.mode = 0444; 532 sd_file->data_attr.read = data_read; 533 534 rc = sysfs_create_bin_file(&sd_file->kobj, &sd_file->data_attr); 535 if (rc) { 536 kobject_put(&sd_file->kobj); 537 return NULL; 538 } 539 540 /* 541 * For completeness only - users interested in entity data should listen 542 * for KOBJ_CHANGE instead. 543 */ 544 kobject_uevent(&sd_file->kobj, KOBJ_ADD); 545 546 /* Don't let a slow Store Data request delay further initialization */ 547 async_schedule(sclp_sd_file_update_async, sd_file); 548 549 return sd_file; 550 } 551 552 /** 553 * sclp_sd_init() - Initialize sclp_sd support and register sysfs files 554 */ 555 static __init int sclp_sd_init(void) 556 { 557 int rc; 558 559 rc = sclp_register(&sclp_sd_register); 560 if (rc) 561 return rc; 562 563 /* Create kset named "sclp_sd" located under /sys/firmware/ */ 564 rc = -ENOMEM; 565 sclp_sd_kset = kset_create_and_add("sclp_sd", NULL, firmware_kobj); 566 if (!sclp_sd_kset) 567 goto err_kset; 568 569 rc = -EINVAL; 570 config_file = sclp_sd_file_create("config", SD_DI_CONFIG); 571 if (!config_file) 572 goto err_config; 573 574 return 0; 575 576 err_config: 577 kset_unregister(sclp_sd_kset); 578 err_kset: 579 sclp_unregister(&sclp_sd_register); 580 581 return rc; 582 } 583 device_initcall(sclp_sd_init); 584