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