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 sclp_sd_sync(page, SD_EQ_HALT, di, 0, 0, NULL, NULL); 325 vfree(data); 326 goto out; 327 } 328 329 out_result: 330 result->esize_bytes = (size_t) esize * PAGE_SIZE; 331 result->dsize_bytes = (size_t) dsize * PAGE_SIZE; 332 result->data = data; 333 334 out: 335 base_asce_free(asce); 336 free_page(page); 337 338 return rc; 339 } 340 341 /** 342 * sclp_sd_data_reset() - Reset Store Data result buffer 343 * @data: Data buffer to reset 344 * 345 * Reset @data to initial state and release associated memory. 346 */ 347 static void sclp_sd_data_reset(struct sclp_sd_data *data) 348 { 349 vfree(data->data); 350 data->data = NULL; 351 data->dsize_bytes = 0; 352 data->esize_bytes = 0; 353 } 354 355 /** 356 * sclp_sd_file_release() - Release function for sclp_sd_file object 357 * @kobj: Kobject embedded in sclp_sd_file object 358 */ 359 static void sclp_sd_file_release(struct kobject *kobj) 360 { 361 struct sclp_sd_file *sd_file = to_sd_file(kobj); 362 363 sclp_sd_data_reset(&sd_file->data); 364 kfree(sd_file); 365 } 366 367 /** 368 * sclp_sd_file_update() - Update contents of sclp_sd_file object 369 * @sd_file: Object to update 370 * 371 * Obtain the current version of data associated with the Store Data entity 372 * @sd_file. 373 * 374 * On success, return %0 and generate a KOBJ_CHANGE event to indicate that the 375 * data may have changed. Return non-zero otherwise. 376 */ 377 static int sclp_sd_file_update(struct sclp_sd_file *sd_file) 378 { 379 const char *name = kobject_name(&sd_file->kobj); 380 struct sclp_sd_data data; 381 int rc; 382 383 rc = sclp_sd_store_data(&data, sd_file->di); 384 if (rc) { 385 if (rc == -ENOENT) { 386 pr_info("No data is available for the %s data entity\n", 387 name); 388 } 389 return rc; 390 } 391 392 mutex_lock(&sd_file->data_mutex); 393 sclp_sd_data_reset(&sd_file->data); 394 sd_file->data = data; 395 mutex_unlock(&sd_file->data_mutex); 396 397 pr_info("A %zu-byte %s data entity was retrieved\n", data.dsize_bytes, 398 name); 399 kobject_uevent(&sd_file->kobj, KOBJ_CHANGE); 400 401 return 0; 402 } 403 404 /** 405 * sclp_sd_file_update_async() - Wrapper for asynchronous update call 406 * @data: Object to update 407 * @cookie: Unused 408 */ 409 static void sclp_sd_file_update_async(void *data, async_cookie_t cookie) 410 { 411 struct sclp_sd_file *sd_file = data; 412 413 sclp_sd_file_update(sd_file); 414 } 415 416 /** 417 * reload_store() - Store function for "reload" sysfs attribute 418 * @kobj: Kobject of sclp_sd_file object 419 * @attr: Reload attribute 420 * @buf: Data written to sysfs attribute 421 * @count: Count of bytes written 422 * 423 * Initiate a reload of the data associated with an sclp_sd_file object. 424 */ 425 static ssize_t reload_store(struct kobject *kobj, struct kobj_attribute *attr, 426 const char *buf, size_t count) 427 { 428 struct sclp_sd_file *sd_file = to_sd_file(kobj); 429 430 sclp_sd_file_update(sd_file); 431 432 return count; 433 } 434 435 static struct kobj_attribute reload_attr = __ATTR_WO(reload); 436 437 static struct attribute *sclp_sd_file_default_attrs[] = { 438 &reload_attr.attr, 439 NULL, 440 }; 441 442 static struct kobj_type sclp_sd_file_ktype = { 443 .sysfs_ops = &kobj_sysfs_ops, 444 .release = sclp_sd_file_release, 445 .default_attrs = sclp_sd_file_default_attrs, 446 }; 447 448 /** 449 * data_read() - Read function for "data" sysfs attribute 450 * @file: Open file pointer 451 * @kobj: Kobject of sclp_sd_file object 452 * @attr: Data attribute 453 * @buffer: Target buffer 454 * @off: Requested file offset 455 * @size: Requested number of bytes 456 * 457 * Store the requested portion of the Store Data entity contents into the 458 * specified buffer. Return the number of bytes stored on success, or %0 459 * on EOF. 460 */ 461 static ssize_t data_read(struct file *file, struct kobject *kobj, 462 struct bin_attribute *attr, char *buffer, 463 loff_t off, size_t size) 464 { 465 struct sclp_sd_file *sd_file = to_sd_file(kobj); 466 size_t data_size; 467 char *data; 468 469 mutex_lock(&sd_file->data_mutex); 470 471 data = sd_file->data.data; 472 data_size = sd_file->data.dsize_bytes; 473 if (!data || off >= data_size) { 474 size = 0; 475 } else { 476 if (off + size > data_size) 477 size = data_size - off; 478 memcpy(buffer, data + off, size); 479 } 480 481 mutex_unlock(&sd_file->data_mutex); 482 483 return size; 484 } 485 486 /** 487 * sclp_sd_file_create() - Add a sysfs file representing a Store Data entity 488 * @name: Name of file 489 * @di: DI value associated with this entity 490 * 491 * Create a sysfs directory with the given @name located under 492 * 493 * /sys/firmware/sclp_sd/ 494 * 495 * The files in this directory can be used to access the contents of the Store 496 * Data entity associated with @DI. 497 * 498 * Return pointer to resulting sclp_sd_file object on success, %NULL otherwise. 499 * The object must be freed by calling kobject_put() on the embedded kobject 500 * pointer after use. 501 */ 502 static __init struct sclp_sd_file *sclp_sd_file_create(const char *name, u8 di) 503 { 504 struct sclp_sd_file *sd_file; 505 int rc; 506 507 sd_file = kzalloc(sizeof(*sd_file), GFP_KERNEL); 508 if (!sd_file) 509 return NULL; 510 sd_file->di = di; 511 mutex_init(&sd_file->data_mutex); 512 513 /* Create kobject located under /sys/firmware/sclp_sd/ */ 514 sd_file->kobj.kset = sclp_sd_kset; 515 rc = kobject_init_and_add(&sd_file->kobj, &sclp_sd_file_ktype, NULL, 516 "%s", name); 517 if (rc) { 518 kobject_put(&sd_file->kobj); 519 return NULL; 520 } 521 522 sysfs_bin_attr_init(&sd_file->data_attr); 523 sd_file->data_attr.attr.name = "data"; 524 sd_file->data_attr.attr.mode = 0444; 525 sd_file->data_attr.read = data_read; 526 527 rc = sysfs_create_bin_file(&sd_file->kobj, &sd_file->data_attr); 528 if (rc) { 529 kobject_put(&sd_file->kobj); 530 return NULL; 531 } 532 533 /* 534 * For completeness only - users interested in entity data should listen 535 * for KOBJ_CHANGE instead. 536 */ 537 kobject_uevent(&sd_file->kobj, KOBJ_ADD); 538 539 /* Don't let a slow Store Data request delay further initialization */ 540 async_schedule(sclp_sd_file_update_async, sd_file); 541 542 return sd_file; 543 } 544 545 /** 546 * sclp_sd_init() - Initialize sclp_sd support and register sysfs files 547 */ 548 static __init int sclp_sd_init(void) 549 { 550 int rc; 551 552 rc = sclp_register(&sclp_sd_register); 553 if (rc) 554 return rc; 555 556 /* Create kset named "sclp_sd" located under /sys/firmware/ */ 557 rc = -ENOMEM; 558 sclp_sd_kset = kset_create_and_add("sclp_sd", NULL, firmware_kobj); 559 if (!sclp_sd_kset) 560 goto err_kset; 561 562 rc = -EINVAL; 563 config_file = sclp_sd_file_create("config", SD_DI_CONFIG); 564 if (!config_file) 565 goto err_config; 566 567 return 0; 568 569 err_config: 570 kset_unregister(sclp_sd_kset); 571 err_kset: 572 sclp_unregister(&sclp_sd_register); 573 574 return rc; 575 } 576 device_initcall(sclp_sd_init); 577