drivers/s390/char/sclp_sd.c

   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);