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 pr_fmt(fmt) "sclp_sd: " fmt
9
10 #include <linux/completion.h>
11 #include <linux/jiffies.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/mutex.h>
19 #include <linux/pgalloc.h>
20
21 #include "sclp.h"
22
23 #define SD_EQ_STORE_DATA 0
24 #define SD_EQ_HALT 1
25 #define SD_EQ_SIZE 2
26
27 #define SD_DI_CONFIG 3
28
29 #define SD_TIMEOUT msecs_to_jiffies(30000)
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 */
sclp_sd_listener_add(struct sclp_sd_listener * listener)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 */
sclp_sd_listener_remove(struct sclp_sd_listener * listener)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 */
sclp_sd_listener_init(struct sclp_sd_listener * listener,u32 id)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 */
sclp_sd_receiver(struct evbuf_header * evbuf_hdr)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 */
sclp_sd_sync(unsigned long page,u8 eq,u8 di,u64 sat,u64 sa,u32 * dsize_ptr,u32 * esize_ptr)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 if (!sclp_sd_register.sclp_send_mask ||
198 !sclp_sd_register.sclp_receive_mask)
199 return -EIO;
200
201 sclp_sd_listener_init(&listener, __pa(sccb));
202 sclp_sd_listener_add(&listener);
203
204 /* Prepare SCCB */
205 memset(sccb, 0, PAGE_SIZE);
206 sccb->hdr.length = sizeof(sccb->hdr) + sizeof(sccb->evbuf);
207 evbuf = &sccb->evbuf;
208 evbuf->hdr.length = sizeof(*evbuf);
209 evbuf->hdr.type = EVTYP_STORE_DATA;
210 evbuf->eq = eq;
211 evbuf->di = di;
212 evbuf->id = listener.id;
213 evbuf->fmt = 1;
214 evbuf->sat = sat;
215 evbuf->sa = sa;
216 if (dsize_ptr)
217 evbuf->dsize = *dsize_ptr;
218
219 /* Perform command */
220 pr_debug("request (eq=%d, di=%d, id=0x%08x)\n", eq, di, listener.id);
221 rc = sclp_sync_request(SCLP_CMDW_WRITE_EVENT_DATA, sccb);
222 pr_debug("request done (rc=%d)\n", rc);
223 if (rc)
224 goto out;
225
226 /* Evaluate response */
227 if (sccb->hdr.response_code == 0x73f0) {
228 pr_debug("event not supported\n");
229 rc = -EIO;
230 goto out_remove;
231 }
232 if (sccb->hdr.response_code != 0x0020 || !(evbuf->hdr.flags & 0x80)) {
233 rc = -EIO;
234 goto out;
235 }
236 if (!(evbuf->rflags & 0x80)) {
237 rc = wait_for_completion_interruptible_timeout(&listener.completion, SD_TIMEOUT);
238 if (rc == 0)
239 rc = -ETIME;
240 if (rc < 0)
241 goto out;
242 rc = 0;
243 evbuf = &listener.evbuf;
244 }
245 switch (evbuf->status) {
246 case 0:
247 if (dsize_ptr)
248 *dsize_ptr = evbuf->dsize;
249 if (esize_ptr)
250 *esize_ptr = evbuf->esize;
251 pr_debug("success (dsize=%u, esize=%u)\n", evbuf->dsize,
252 evbuf->esize);
253 break;
254 case 3:
255 rc = -ENOENT;
256 break;
257 default:
258 rc = -EIO;
259 break;
260
261 }
262
263 out:
264 if (rc && rc != -ENOENT) {
265 /* Provide some information about what went wrong */
266 pr_warn("Store Data request failed (eq=%d, di=%d, "
267 "response=0x%04x, flags=0x%02x, status=%d, rc=%d)\n",
268 eq, di, sccb->hdr.response_code, evbuf->hdr.flags,
269 evbuf->status, rc);
270 }
271
272 out_remove:
273 sclp_sd_listener_remove(&listener);
274
275 return rc;
276 }
277
278 /**
279 * sclp_sd_store_data() - Obtain data for specified Store Data entity
280 * @result: Resulting data
281 * @di: DI value associated with this entity
282 *
283 * Perform a series of Store Data requests to obtain the size and contents of
284 * the specified Store Data entity.
285 *
286 * Return:
287 * %0: Success - result is stored in @result. @result->data must be
288 * released using vfree() after use.
289 * %-ENOENT: No data available for this entity
290 * %<0: Other error
291 */
sclp_sd_store_data(struct sclp_sd_data * result,u8 di)292 static int sclp_sd_store_data(struct sclp_sd_data *result, u8 di)
293 {
294 u32 dsize = 0, esize = 0;
295 unsigned long page, asce = 0;
296 void *data = NULL;
297 int rc;
298
299 page = __get_free_page(GFP_KERNEL | GFP_DMA);
300 if (!page)
301 return -ENOMEM;
302
303 /* Get size */
304 rc = sclp_sd_sync(page, SD_EQ_SIZE, di, 0, 0, &dsize, &esize);
305 if (rc)
306 goto out;
307 if (dsize == 0)
308 goto out_result;
309
310 /* Allocate memory */
311 data = vzalloc(array_size((size_t)dsize, PAGE_SIZE));
312 if (!data) {
313 rc = -ENOMEM;
314 goto out;
315 }
316
317 /* Get translation table for buffer */
318 asce = base_asce_alloc((unsigned long) data, dsize);
319 if (!asce) {
320 vfree(data);
321 rc = -ENOMEM;
322 goto out;
323 }
324
325 /* Get data */
326 rc = sclp_sd_sync(page, SD_EQ_STORE_DATA, di, asce, (u64) data, &dsize,
327 &esize);
328 if (rc) {
329 /* Cancel running request if interrupted or timed out */
330 if (rc == -ERESTARTSYS || rc == -ETIME) {
331 if (sclp_sd_sync(page, SD_EQ_HALT, di, 0, 0, NULL, NULL)) {
332 pr_warn("Could not stop Store Data request - leaking at least %zu bytes\n",
333 (size_t)dsize * PAGE_SIZE);
334 data = NULL;
335 asce = 0;
336 }
337 }
338 vfree(data);
339 goto out;
340 }
341
342 out_result:
343 result->esize_bytes = (size_t) esize * PAGE_SIZE;
344 result->dsize_bytes = (size_t) dsize * PAGE_SIZE;
345 result->data = data;
346
347 out:
348 base_asce_free(asce);
349 free_page(page);
350
351 return rc;
352 }
353
354 /**
355 * sclp_sd_data_reset() - Reset Store Data result buffer
356 * @data: Data buffer to reset
357 *
358 * Reset @data to initial state and release associated memory.
359 */
sclp_sd_data_reset(struct sclp_sd_data * data)360 static void sclp_sd_data_reset(struct sclp_sd_data *data)
361 {
362 vfree(data->data);
363 data->data = NULL;
364 data->dsize_bytes = 0;
365 data->esize_bytes = 0;
366 }
367
368 /**
369 * sclp_sd_file_release() - Release function for sclp_sd_file object
370 * @kobj: Kobject embedded in sclp_sd_file object
371 */
sclp_sd_file_release(struct kobject * kobj)372 static void sclp_sd_file_release(struct kobject *kobj)
373 {
374 struct sclp_sd_file *sd_file = to_sd_file(kobj);
375
376 sclp_sd_data_reset(&sd_file->data);
377 kfree(sd_file);
378 }
379
380 /**
381 * sclp_sd_file_update() - Update contents of sclp_sd_file object
382 * @sd_file: Object to update
383 *
384 * Obtain the current version of data associated with the Store Data entity
385 * @sd_file.
386 *
387 * On success, return %0 and generate a KOBJ_CHANGE event to indicate that the
388 * data may have changed. Return non-zero otherwise.
389 */
sclp_sd_file_update(struct sclp_sd_file * sd_file)390 static int sclp_sd_file_update(struct sclp_sd_file *sd_file)
391 {
392 const char *name = kobject_name(&sd_file->kobj);
393 struct sclp_sd_data data;
394 int rc;
395
396 rc = sclp_sd_store_data(&data, sd_file->di);
397 if (rc) {
398 if (rc == -ENOENT) {
399 pr_info("No data is available for the %s data entity\n",
400 name);
401 }
402 return rc;
403 }
404
405 mutex_lock(&sd_file->data_mutex);
406 sclp_sd_data_reset(&sd_file->data);
407 sd_file->data = data;
408 mutex_unlock(&sd_file->data_mutex);
409
410 pr_info("A %zu-byte %s data entity was retrieved\n", data.dsize_bytes,
411 name);
412 kobject_uevent(&sd_file->kobj, KOBJ_CHANGE);
413
414 return 0;
415 }
416
417 /**
418 * sclp_sd_file_update_async() - Wrapper for asynchronous update call
419 * @data: Object to update
420 * @cookie: Unused
421 */
sclp_sd_file_update_async(void * data,async_cookie_t cookie)422 static void sclp_sd_file_update_async(void *data, async_cookie_t cookie)
423 {
424 struct sclp_sd_file *sd_file = data;
425
426 sclp_sd_file_update(sd_file);
427 }
428
429 /**
430 * reload_store() - Store function for "reload" sysfs attribute
431 * @kobj: Kobject of sclp_sd_file object
432 * @attr: Reload attribute
433 * @buf: Data written to sysfs attribute
434 * @count: Count of bytes written
435 *
436 * Initiate a reload of the data associated with an sclp_sd_file object.
437 */
reload_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)438 static ssize_t reload_store(struct kobject *kobj, struct kobj_attribute *attr,
439 const char *buf, size_t count)
440 {
441 struct sclp_sd_file *sd_file = to_sd_file(kobj);
442
443 sclp_sd_file_update(sd_file);
444
445 return count;
446 }
447
448 static struct kobj_attribute reload_attr = __ATTR_WO(reload);
449
450 static struct attribute *sclp_sd_file_default_attrs[] = {
451 &reload_attr.attr,
452 NULL,
453 };
454 ATTRIBUTE_GROUPS(sclp_sd_file_default);
455
456 static struct kobj_type sclp_sd_file_ktype = {
457 .sysfs_ops = &kobj_sysfs_ops,
458 .release = sclp_sd_file_release,
459 .default_groups = sclp_sd_file_default_groups,
460 };
461
462 /**
463 * data_read() - Read function for "data" sysfs attribute
464 * @file: Open file pointer
465 * @kobj: Kobject of sclp_sd_file object
466 * @attr: Data attribute
467 * @buffer: Target buffer
468 * @off: Requested file offset
469 * @size: Requested number of bytes
470 *
471 * Store the requested portion of the Store Data entity contents into the
472 * specified buffer. Return the number of bytes stored on success, or %0
473 * on EOF.
474 */
data_read(struct file * file,struct kobject * kobj,const struct bin_attribute * attr,char * buffer,loff_t off,size_t size)475 static ssize_t data_read(struct file *file, struct kobject *kobj,
476 const struct bin_attribute *attr, char *buffer,
477 loff_t off, size_t size)
478 {
479 struct sclp_sd_file *sd_file = to_sd_file(kobj);
480 size_t data_size;
481 char *data;
482
483 mutex_lock(&sd_file->data_mutex);
484
485 data = sd_file->data.data;
486 data_size = sd_file->data.dsize_bytes;
487 if (!data || off >= data_size) {
488 size = 0;
489 } else {
490 if (off + size > data_size)
491 size = data_size - off;
492 memcpy(buffer, data + off, size);
493 }
494
495 mutex_unlock(&sd_file->data_mutex);
496
497 return size;
498 }
499
500 /**
501 * sclp_sd_file_create() - Add a sysfs file representing a Store Data entity
502 * @name: Name of file
503 * @di: DI value associated with this entity
504 *
505 * Create a sysfs directory with the given @name located under
506 *
507 * /sys/firmware/sclp_sd/
508 *
509 * The files in this directory can be used to access the contents of the Store
510 * Data entity associated with @DI.
511 *
512 * Return pointer to resulting sclp_sd_file object on success, %NULL otherwise.
513 * The object must be freed by calling kobject_put() on the embedded kobject
514 * pointer after use.
515 */
sclp_sd_file_create(const char * name,u8 di)516 static __init struct sclp_sd_file *sclp_sd_file_create(const char *name, u8 di)
517 {
518 struct sclp_sd_file *sd_file;
519 int rc;
520
521 sd_file = kzalloc(sizeof(*sd_file), GFP_KERNEL);
522 if (!sd_file)
523 return NULL;
524 sd_file->di = di;
525 mutex_init(&sd_file->data_mutex);
526
527 /* Create kobject located under /sys/firmware/sclp_sd/ */
528 sd_file->kobj.kset = sclp_sd_kset;
529 rc = kobject_init_and_add(&sd_file->kobj, &sclp_sd_file_ktype, NULL,
530 "%s", name);
531 if (rc) {
532 kobject_put(&sd_file->kobj);
533 return NULL;
534 }
535
536 sysfs_bin_attr_init(&sd_file->data_attr);
537 sd_file->data_attr.attr.name = "data";
538 sd_file->data_attr.attr.mode = 0444;
539 sd_file->data_attr.read = data_read;
540
541 rc = sysfs_create_bin_file(&sd_file->kobj, &sd_file->data_attr);
542 if (rc) {
543 kobject_put(&sd_file->kobj);
544 return NULL;
545 }
546
547 /*
548 * For completeness only - users interested in entity data should listen
549 * for KOBJ_CHANGE instead.
550 */
551 kobject_uevent(&sd_file->kobj, KOBJ_ADD);
552
553 /* Don't let a slow Store Data request delay further initialization */
554 async_schedule(sclp_sd_file_update_async, sd_file);
555
556 return sd_file;
557 }
558
559 /**
560 * sclp_sd_init() - Initialize sclp_sd support and register sysfs files
561 */
sclp_sd_init(void)562 static __init int sclp_sd_init(void)
563 {
564 int rc;
565
566 rc = sclp_register(&sclp_sd_register);
567 if (rc)
568 return rc;
569
570 /* Create kset named "sclp_sd" located under /sys/firmware/ */
571 rc = -ENOMEM;
572 sclp_sd_kset = kset_create_and_add("sclp_sd", NULL, firmware_kobj);
573 if (!sclp_sd_kset)
574 goto err_kset;
575
576 rc = -EINVAL;
577 config_file = sclp_sd_file_create("config", SD_DI_CONFIG);
578 if (!config_file)
579 goto err_config;
580
581 return 0;
582
583 err_config:
584 kset_unregister(sclp_sd_kset);
585 err_kset:
586 sclp_unregister(&sclp_sd_register);
587
588 return rc;
589 }
590 device_initcall(sclp_sd_init);
591