1// SPDX-License-Identifier: GPL-2.0
2/*
3 * core function to access sclp interface
4 *
5 * Copyright IBM Corp. 1999, 2009
6 *
7 * Author(s): Martin Peschke <mpeschke@de.ibm.com>
8 * Martin Schwidefsky <schwidefsky@de.ibm.com>
9 */
10
11#include <linux/kernel_stat.h>
12#include <linux/export.h>
13#include <linux/module.h>
14#include <linux/err.h>
15#include <linux/panic_notifier.h>
16#include <linux/spinlock.h>
17#include <linux/interrupt.h>
18#include <linux/timer.h>
19#include <linux/reboot.h>
20#include <linux/jiffies.h>
21#include <linux/init.h>
22#include <linux/platform_device.h>
23#include <asm/types.h>
24#include <asm/irq.h>
25#include <asm/debug.h>
26
27#include "sclp.h"
28
29#define SCLP_HEADER "sclp: "
30
31struct sclp_trace_entry {
32 char id[4] __nonstring;
33 u32 a;
34 u64 b;
35};
36
37#define SCLP_TRACE_ENTRY_SIZE sizeof(struct sclp_trace_entry)
38#define SCLP_TRACE_MAX_SIZE 128
39#define SCLP_TRACE_EVENT_MAX_SIZE 64
40
41/* Debug trace area intended for all entries in abbreviated form. */
42DEFINE_STATIC_DEBUG_INFO(sclp_debug, "sclp", 8, 1, SCLP_TRACE_ENTRY_SIZE,
43 &debug_hex_ascii_view);
44
45/* Error trace area intended for full entries relating to failed requests. */
46DEFINE_STATIC_DEBUG_INFO(sclp_debug_err, "sclp_err", 4, 1,
47 SCLP_TRACE_ENTRY_SIZE, &debug_hex_ascii_view);
48
49/* Lock to protect internal data consistency. */
50static DEFINE_SPINLOCK(sclp_lock);
51
52/* Mask of events that we can send to the sclp interface. */
53static sccb_mask_t sclp_receive_mask;
54
55/* Mask of events that we can receive from the sclp interface. */
56static sccb_mask_t sclp_send_mask;
57
58/* List of registered event listeners and senders. */
59static LIST_HEAD(sclp_reg_list);
60
61/* List of queued requests. */
62static LIST_HEAD(sclp_req_queue);
63
64/* Data for read and init requests. */
65static struct sclp_req sclp_read_req;
66static struct sclp_req sclp_init_req;
67static void *sclp_read_sccb;
68static struct init_sccb *sclp_init_sccb;
69
70/* Number of console pages to allocate, used by sclp_con.c and sclp_vt220.c */
71int sclp_console_pages = SCLP_CONSOLE_PAGES;
72/* Flag to indicate if buffer pages are dropped on buffer full condition */
73bool sclp_console_drop = true;
74/* Number of times the console dropped buffer pages */
75unsigned long sclp_console_full;
76
77/* The currently active SCLP command word. */
78static sclp_cmdw_t active_cmd;
79
80static inline struct sccb_header *sclpint_to_sccb(u32 sccb_int)
81{
82 if (sccb_int)
83 return __va(sccb_int);
84 return NULL;
85}
86
87static inline void sclp_trace(int prio, char *id, u32 a, u64 b, bool err)
88{
89 struct sclp_trace_entry e;
90
91 memset(&e, 0, sizeof(e));
92 strtomem(e.id, id);
93 e.a = a;
94 e.b = b;
95 debug_event(&sclp_debug, prio, &e, sizeof(e));
96 if (err)
97 debug_event(&sclp_debug_err, 0, &e, sizeof(e));
98}
99
100static inline int no_zeroes_len(void *data, int len)
101{
102 char *d = data;
103
104 /* Minimize trace area usage by not tracing trailing zeroes. */
105 while (len > SCLP_TRACE_ENTRY_SIZE && d[len - 1] == 0)
106 len--;
107
108 return len;
109}
110
111static inline void sclp_trace_bin(int prio, void *d, int len, int errlen)
112{
113 debug_event(&sclp_debug, prio, d, no_zeroes_len(data: d, len));
114 if (errlen)
115 debug_event(&sclp_debug_err, 0, d, no_zeroes_len(data: d, len: errlen));
116}
117
118static inline int abbrev_len(sclp_cmdw_t cmd, struct sccb_header *sccb)
119{
120 struct evbuf_header *evbuf = (struct evbuf_header *)(sccb + 1);
121 int len = sccb->length, limit = SCLP_TRACE_MAX_SIZE;
122
123 /* Full SCCB tracing if debug level is set to max. */
124 if (sclp_debug.level == DEBUG_MAX_LEVEL)
125 return len;
126
127 /* Minimal tracing for console writes. */
128 if (cmd == SCLP_CMDW_WRITE_EVENT_DATA &&
129 (evbuf->type == EVTYP_MSG || evbuf->type == EVTYP_VT220MSG))
130 limit = SCLP_TRACE_ENTRY_SIZE;
131
132 return min(len, limit);
133}
134
135static inline void sclp_trace_sccb(int prio, char *id, u32 a, u64 b,
136 sclp_cmdw_t cmd, struct sccb_header *sccb,
137 bool err)
138{
139 sclp_trace(prio, id, a, b, err);
140 if (sccb) {
141 sclp_trace_bin(prio: prio + 1, d: sccb, len: abbrev_len(cmd, sccb),
142 errlen: err ? sccb->length : 0);
143 }
144}
145
146static inline void sclp_trace_evbuf(int prio, char *id, u32 a, u64 b,
147 struct evbuf_header *evbuf, bool err)
148{
149 sclp_trace(prio, id, a, b, err);
150 sclp_trace_bin(prio: prio + 1, d: evbuf,
151 min((int)evbuf->length, (int)SCLP_TRACE_EVENT_MAX_SIZE),
152 errlen: err ? evbuf->length : 0);
153}
154
155static inline void sclp_trace_req(int prio, char *id, struct sclp_req *req,
156 bool err)
157{
158 struct sccb_header *sccb = req->sccb;
159 union {
160 struct {
161 u16 status;
162 u16 response;
163 u16 timeout;
164 u16 start_count;
165 };
166 u64 b;
167 } summary;
168
169 summary.status = req->status;
170 summary.response = sccb ? sccb->response_code : 0;
171 summary.timeout = (u16)req->queue_timeout;
172 summary.start_count = (u16)req->start_count;
173
174 sclp_trace(prio, id, __pa(sccb), b: summary.b, err);
175}
176
177static inline void sclp_trace_register(int prio, char *id, u32 a, u64 b,
178 struct sclp_register *reg)
179{
180 struct {
181 u64 receive;
182 u64 send;
183 } d;
184
185 d.receive = reg->receive_mask;
186 d.send = reg->send_mask;
187
188 sclp_trace(prio, id, a, b, err: false);
189 sclp_trace_bin(prio, d: &d, len: sizeof(d), errlen: 0);
190}
191
192static int __init sclp_setup_console_pages(char *str)
193{
194 int pages, rc;
195
196 rc = kstrtoint(s: str, base: 0, res: &pages);
197 if (!rc && pages >= SCLP_CONSOLE_PAGES)
198 sclp_console_pages = pages;
199 return 1;
200}
201
202__setup("sclp_con_pages=", sclp_setup_console_pages);
203
204static int __init sclp_setup_console_drop(char *str)
205{
206 return kstrtobool(s: str, res: &sclp_console_drop) == 0;
207}
208
209__setup("sclp_con_drop=", sclp_setup_console_drop);
210
211/* Timer for request retries. */
212static struct timer_list sclp_request_timer;
213
214/* Timer for queued requests. */
215static struct timer_list sclp_queue_timer;
216
217/* Internal state: is a request active at the sclp? */
218static volatile enum sclp_running_state_t {
219 sclp_running_state_idle,
220 sclp_running_state_running,
221 sclp_running_state_reset_pending
222} sclp_running_state = sclp_running_state_idle;
223
224/* Internal state: is a read request pending? */
225static volatile enum sclp_reading_state_t {
226 sclp_reading_state_idle,
227 sclp_reading_state_reading
228} sclp_reading_state = sclp_reading_state_idle;
229
230/* Internal state: is the driver currently serving requests? */
231static volatile enum sclp_activation_state_t {
232 sclp_activation_state_active,
233 sclp_activation_state_deactivating,
234 sclp_activation_state_inactive,
235 sclp_activation_state_activating
236} sclp_activation_state = sclp_activation_state_active;
237
238/* Internal state: is an init mask request pending? */
239static volatile enum sclp_mask_state_t {
240 sclp_mask_state_idle,
241 sclp_mask_state_initializing
242} sclp_mask_state = sclp_mask_state_idle;
243
244/* Maximum retry counts */
245#define SCLP_INIT_RETRY 3
246#define SCLP_MASK_RETRY 3
247
248/* Timeout intervals in seconds.*/
249#define SCLP_BUSY_INTERVAL 10
250#define SCLP_RETRY_INTERVAL 30
251
252static void sclp_request_timeout(bool force_restart);
253static void sclp_process_queue(void);
254static void __sclp_make_read_req(void);
255static int sclp_init_mask(int calculate);
256
257static void
258__sclp_queue_read_req(void)
259{
260 if (sclp_reading_state == sclp_reading_state_idle) {
261 sclp_reading_state = sclp_reading_state_reading;
262 __sclp_make_read_req();
263 /* Add request to head of queue */
264 list_add(new: &sclp_read_req.list, head: &sclp_req_queue);
265 }
266}
267
268/* Set up request retry timer. Called while sclp_lock is locked. */
269static inline void
270__sclp_set_request_timer(unsigned long time, void (*cb)(struct timer_list *))
271{
272 timer_delete(timer: &sclp_request_timer);
273 sclp_request_timer.function = cb;
274 sclp_request_timer.expires = jiffies + time;
275 add_timer(timer: &sclp_request_timer);
276}
277
278static void sclp_request_timeout_restart(struct timer_list *unused)
279{
280 sclp_request_timeout(force_restart: true);
281}
282
283static void sclp_request_timeout_normal(struct timer_list *unused)
284{
285 sclp_request_timeout(force_restart: false);
286}
287
288/* Request timeout handler. Restart the request queue. If force_restart,
289 * force restart of running request. */
290static void sclp_request_timeout(bool force_restart)
291{
292 unsigned long flags;
293
294 /* TMO: A timeout occurred (a=force_restart) */
295 sclp_trace(prio: 2, id: "TMO", a: force_restart, b: 0, err: true);
296
297 spin_lock_irqsave(&sclp_lock, flags);
298 if (force_restart) {
299 if (sclp_running_state == sclp_running_state_running) {
300 /* Break running state and queue NOP read event request
301 * to get a defined interface state. */
302 __sclp_queue_read_req();
303 sclp_running_state = sclp_running_state_idle;
304 }
305 } else {
306 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
307 cb: sclp_request_timeout_normal);
308 }
309 spin_unlock_irqrestore(lock: &sclp_lock, flags);
310 sclp_process_queue();
311}
312
313/*
314 * Returns the expire value in jiffies of the next pending request timeout,
315 * if any. Needs to be called with sclp_lock.
316 */
317static unsigned long __sclp_req_queue_find_next_timeout(void)
318{
319 unsigned long expires_next = 0;
320 struct sclp_req *req;
321
322 list_for_each_entry(req, &sclp_req_queue, list) {
323 if (!req->queue_expires)
324 continue;
325 if (!expires_next ||
326 (time_before(req->queue_expires, expires_next)))
327 expires_next = req->queue_expires;
328 }
329 return expires_next;
330}
331
332/*
333 * Returns expired request, if any, and removes it from the list.
334 */
335static struct sclp_req *__sclp_req_queue_remove_expired_req(void)
336{
337 unsigned long flags, now;
338 struct sclp_req *req;
339
340 spin_lock_irqsave(&sclp_lock, flags);
341 now = jiffies;
342 /* Don't need list_for_each_safe because we break out after list_del */
343 list_for_each_entry(req, &sclp_req_queue, list) {
344 if (!req->queue_expires)
345 continue;
346 if (time_before_eq(req->queue_expires, now)) {
347 if (req->status == SCLP_REQ_QUEUED) {
348 req->status = SCLP_REQ_QUEUED_TIMEOUT;
349 list_del(entry: &req->list);
350 goto out;
351 }
352 }
353 }
354 req = NULL;
355out:
356 spin_unlock_irqrestore(lock: &sclp_lock, flags);
357 return req;
358}
359
360/*
361 * Timeout handler for queued requests. Removes request from list and
362 * invokes callback. This timer can be set per request in situations where
363 * waiting too long would be harmful to the system, e.g. during SE reboot.
364 */
365static void sclp_req_queue_timeout(struct timer_list *unused)
366{
367 unsigned long flags, expires_next;
368 struct sclp_req *req;
369
370 do {
371 req = __sclp_req_queue_remove_expired_req();
372
373 if (req) {
374 /* RQTM: Request timed out (a=sccb, b=summary) */
375 sclp_trace_req(prio: 2, id: "RQTM", req, err: true);
376 }
377
378 if (req && req->callback)
379 req->callback(req, req->callback_data);
380 } while (req);
381
382 spin_lock_irqsave(&sclp_lock, flags);
383 expires_next = __sclp_req_queue_find_next_timeout();
384 if (expires_next)
385 mod_timer(timer: &sclp_queue_timer, expires: expires_next);
386 spin_unlock_irqrestore(lock: &sclp_lock, flags);
387}
388
389static int sclp_service_call_trace(sclp_cmdw_t command, void *sccb)
390{
391 static u64 srvc_count;
392 int rc;
393
394 /* SRV1: Service call about to be issued (a=command, b=sccb address) */
395 sclp_trace_sccb(prio: 0, id: "SRV1", a: command, b: (u64)sccb, cmd: command, sccb, err: false);
396
397 rc = sclp_service_call(command, sccb);
398
399 /* SRV2: Service call was issued (a=rc, b=SRVC sequence number) */
400 sclp_trace(prio: 0, id: "SRV2", a: -rc, b: ++srvc_count, err: rc != 0);
401
402 if (rc == 0)
403 active_cmd = command;
404
405 return rc;
406}
407
408/* Try to start a request. Return zero if the request was successfully
409 * started or if it will be started at a later time. Return non-zero otherwise.
410 * Called while sclp_lock is locked. */
411static int
412__sclp_start_request(struct sclp_req *req)
413{
414 int rc;
415
416 if (sclp_running_state != sclp_running_state_idle)
417 return 0;
418 timer_delete(timer: &sclp_request_timer);
419 rc = sclp_service_call_trace(command: req->command, sccb: req->sccb);
420 req->start_count++;
421
422 if (rc == 0) {
423 /* Successfully started request */
424 req->status = SCLP_REQ_RUNNING;
425 sclp_running_state = sclp_running_state_running;
426 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
427 cb: sclp_request_timeout_restart);
428 return 0;
429 } else if (rc == -EBUSY) {
430 /* Try again later */
431 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
432 cb: sclp_request_timeout_normal);
433 return 0;
434 }
435 /* Request failed */
436 req->status = SCLP_REQ_FAILED;
437 return rc;
438}
439
440/* Try to start queued requests. */
441static void
442sclp_process_queue(void)
443{
444 struct sclp_req *req;
445 int rc;
446 unsigned long flags;
447
448 spin_lock_irqsave(&sclp_lock, flags);
449 if (sclp_running_state != sclp_running_state_idle) {
450 spin_unlock_irqrestore(lock: &sclp_lock, flags);
451 return;
452 }
453 timer_delete(timer: &sclp_request_timer);
454 while (!list_empty(head: &sclp_req_queue)) {
455 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
456 rc = __sclp_start_request(req);
457 if (rc == 0)
458 break;
459 /* Request failed */
460 if (req->start_count > 1) {
461 /* Cannot abort already submitted request - could still
462 * be active at the SCLP */
463 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
464 cb: sclp_request_timeout_normal);
465 break;
466 }
467 /* Post-processing for aborted request */
468 list_del(entry: &req->list);
469
470 /* RQAB: Request aborted (a=sccb, b=summary) */
471 sclp_trace_req(prio: 2, id: "RQAB", req, err: true);
472
473 if (req->callback) {
474 spin_unlock_irqrestore(lock: &sclp_lock, flags);
475 req->callback(req, req->callback_data);
476 spin_lock_irqsave(&sclp_lock, flags);
477 }
478 }
479 spin_unlock_irqrestore(lock: &sclp_lock, flags);
480}
481
482static int __sclp_can_add_request(struct sclp_req *req)
483{
484 if (req == &sclp_init_req)
485 return 1;
486 if (sclp_init_state != sclp_init_state_initialized)
487 return 0;
488 if (sclp_activation_state != sclp_activation_state_active)
489 return 0;
490 return 1;
491}
492
493/* Queue a new request. Return zero on success, non-zero otherwise. */
494int
495sclp_add_request(struct sclp_req *req)
496{
497 unsigned long flags;
498 int rc;
499
500 spin_lock_irqsave(&sclp_lock, flags);
501 if (!__sclp_can_add_request(req)) {
502 spin_unlock_irqrestore(lock: &sclp_lock, flags);
503 return -EIO;
504 }
505
506 /* RQAD: Request was added (a=sccb, b=caller) */
507 sclp_trace(prio: 2, id: "RQAD", __pa(req->sccb), _RET_IP_, err: false);
508
509 req->status = SCLP_REQ_QUEUED;
510 req->start_count = 0;
511 list_add_tail(new: &req->list, head: &sclp_req_queue);
512 rc = 0;
513 if (req->queue_timeout) {
514 req->queue_expires = jiffies + req->queue_timeout * HZ;
515 if (!timer_pending(timer: &sclp_queue_timer) ||
516 time_after(sclp_queue_timer.expires, req->queue_expires))
517 mod_timer(timer: &sclp_queue_timer, expires: req->queue_expires);
518 } else
519 req->queue_expires = 0;
520 /* Start if request is first in list */
521 if (sclp_running_state == sclp_running_state_idle &&
522 req->list.prev == &sclp_req_queue) {
523 rc = __sclp_start_request(req);
524 if (rc)
525 list_del(entry: &req->list);
526 }
527 spin_unlock_irqrestore(lock: &sclp_lock, flags);
528 return rc;
529}
530
531EXPORT_SYMBOL(sclp_add_request);
532
533/* Dispatch events found in request buffer to registered listeners. Return 0
534 * if all events were dispatched, non-zero otherwise. */
535static int
536sclp_dispatch_evbufs(struct sccb_header *sccb)
537{
538 unsigned long flags;
539 struct evbuf_header *evbuf;
540 struct list_head *l;
541 struct sclp_register *reg;
542 int offset;
543 int rc;
544
545 spin_lock_irqsave(&sclp_lock, flags);
546 rc = 0;
547 for (offset = sizeof(struct sccb_header); offset < sccb->length;
548 offset += evbuf->length) {
549 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
550 /* Check for malformed hardware response */
551 if (evbuf->length == 0)
552 break;
553 /* Search for event handler */
554 reg = NULL;
555 list_for_each(l, &sclp_reg_list) {
556 reg = list_entry(l, struct sclp_register, list);
557 if (reg->receive_mask & SCLP_EVTYP_MASK(evbuf->type))
558 break;
559 else
560 reg = NULL;
561 }
562
563 /* EVNT: Event callback (b=receiver) */
564 sclp_trace_evbuf(prio: 2, id: "EVNT", a: 0, b: reg ? (u64)reg->receiver_fn : 0,
565 evbuf, err: !reg);
566
567 if (reg && reg->receiver_fn) {
568 spin_unlock_irqrestore(lock: &sclp_lock, flags);
569 reg->receiver_fn(evbuf);
570 spin_lock_irqsave(&sclp_lock, flags);
571 } else if (reg == NULL)
572 rc = -EOPNOTSUPP;
573 }
574 spin_unlock_irqrestore(lock: &sclp_lock, flags);
575 return rc;
576}
577
578/* Read event data request callback. */
579static void
580sclp_read_cb(struct sclp_req *req, void *data)
581{
582 unsigned long flags;
583 struct sccb_header *sccb;
584
585 sccb = (struct sccb_header *) req->sccb;
586 if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
587 sccb->response_code == 0x220))
588 sclp_dispatch_evbufs(sccb);
589 spin_lock_irqsave(&sclp_lock, flags);
590 sclp_reading_state = sclp_reading_state_idle;
591 spin_unlock_irqrestore(lock: &sclp_lock, flags);
592}
593
594/* Prepare read event data request. Called while sclp_lock is locked. */
595static void __sclp_make_read_req(void)
596{
597 struct sccb_header *sccb;
598
599 sccb = (struct sccb_header *) sclp_read_sccb;
600 clear_page(page: sccb);
601 memset(&sclp_read_req, 0, sizeof(struct sclp_req));
602 sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
603 sclp_read_req.status = SCLP_REQ_QUEUED;
604 sclp_read_req.start_count = 0;
605 sclp_read_req.callback = sclp_read_cb;
606 sclp_read_req.sccb = sccb;
607 sccb->length = PAGE_SIZE;
608 sccb->function_code = 0;
609 sccb->control_mask[2] = 0x80;
610}
611
612/* Search request list for request with matching sccb. Return request if found,
613 * NULL otherwise. Called while sclp_lock is locked. */
614static inline struct sclp_req *
615__sclp_find_req(u32 sccb)
616{
617 struct list_head *l;
618 struct sclp_req *req;
619
620 list_for_each(l, &sclp_req_queue) {
621 req = list_entry(l, struct sclp_req, list);
622 if (sccb == __pa(req->sccb))
623 return req;
624 }
625 return NULL;
626}
627
628static bool ok_response(u32 sccb_int, sclp_cmdw_t cmd)
629{
630 struct sccb_header *sccb = sclpint_to_sccb(sccb_int);
631 struct evbuf_header *evbuf;
632 u16 response;
633
634 if (!sccb)
635 return true;
636
637 /* Check SCCB response. */
638 response = sccb->response_code & 0xff;
639 if (response != 0x10 && response != 0x20)
640 return false;
641
642 /* Check event-processed flag on outgoing events. */
643 if (cmd == SCLP_CMDW_WRITE_EVENT_DATA) {
644 evbuf = (struct evbuf_header *)(sccb + 1);
645 if (!(evbuf->flags & 0x80))
646 return false;
647 }
648
649 return true;
650}
651
652/* Handler for external interruption. Perform request post-processing.
653 * Prepare read event data request if necessary. Start processing of next
654 * request on queue. */
655static void sclp_interrupt_handler(struct ext_code ext_code,
656 unsigned int param32, unsigned long param64)
657{
658 struct sclp_req *req;
659 u32 finished_sccb;
660 u32 evbuf_pending;
661
662 inc_irq_stat(IRQEXT_SCP);
663 spin_lock(lock: &sclp_lock);
664 finished_sccb = param32 & 0xfffffff8;
665 evbuf_pending = param32 & 0x3;
666
667 /* INT: Interrupt received (a=intparm, b=cmd) */
668 sclp_trace_sccb(prio: 0, id: "INT", a: param32, b: active_cmd, cmd: active_cmd,
669 sccb: sclpint_to_sccb(sccb_int: finished_sccb),
670 err: !ok_response(sccb_int: finished_sccb, cmd: active_cmd));
671
672 if (finished_sccb) {
673 timer_delete(timer: &sclp_request_timer);
674 sclp_running_state = sclp_running_state_reset_pending;
675 req = __sclp_find_req(sccb: finished_sccb);
676 if (req) {
677 /* Request post-processing */
678 list_del(entry: &req->list);
679 req->status = SCLP_REQ_DONE;
680
681 /* RQOK: Request success (a=sccb, b=summary) */
682 sclp_trace_req(prio: 2, id: "RQOK", req, err: false);
683
684 if (req->callback) {
685 spin_unlock(lock: &sclp_lock);
686 req->callback(req, req->callback_data);
687 spin_lock(lock: &sclp_lock);
688 }
689 } else {
690 /* UNEX: Unexpected SCCB completion (a=sccb address) */
691 sclp_trace(prio: 0, id: "UNEX", a: finished_sccb, b: 0, err: true);
692 }
693 sclp_running_state = sclp_running_state_idle;
694 active_cmd = 0;
695 }
696 if (evbuf_pending &&
697 sclp_activation_state == sclp_activation_state_active)
698 __sclp_queue_read_req();
699 spin_unlock(lock: &sclp_lock);
700 sclp_process_queue();
701}
702
703/* Convert interval in jiffies to TOD ticks. */
704static inline u64
705sclp_tod_from_jiffies(unsigned long jiffies)
706{
707 return (u64) (jiffies / HZ) << 32;
708}
709
710/* Wait until a currently running request finished. Note: while this function
711 * is running, no timers are served on the calling CPU. */
712void
713sclp_sync_wait(void)
714{
715 unsigned long long old_tick;
716 struct ctlreg cr0, cr0_sync;
717 unsigned long flags;
718 static u64 sync_count;
719 u64 timeout;
720 int irq_context;
721
722 /* SYN1: Synchronous wait start (a=runstate, b=sync count) */
723 sclp_trace(prio: 4, id: "SYN1", a: sclp_running_state, b: ++sync_count, err: false);
724
725 /* We'll be disabling timer interrupts, so we need a custom timeout
726 * mechanism */
727 timeout = 0;
728 if (timer_pending(timer: &sclp_request_timer)) {
729 /* Get timeout TOD value */
730 timeout = get_tod_clock_monotonic() +
731 sclp_tod_from_jiffies(jiffies: sclp_request_timer.expires -
732 jiffies);
733 }
734 local_irq_save(flags);
735 /* Prevent bottom half from executing once we force interrupts open */
736 irq_context = in_interrupt();
737 if (!irq_context)
738 local_bh_disable();
739 /* Enable service-signal interruption, disable timer interrupts */
740 old_tick = local_tick_disable();
741 trace_hardirqs_on();
742 local_ctl_store(0, &cr0);
743 cr0_sync.val = cr0.val & ~CR0_IRQ_SUBCLASS_MASK;
744 cr0_sync.val |= 1UL << (63 - 54);
745 local_ctl_load(0, &cr0_sync);
746 arch_local_irq_enable_external();
747 /* Loop until driver state indicates finished request */
748 while (sclp_running_state != sclp_running_state_idle) {
749 /* Check for expired request timer */
750 if (get_tod_clock_monotonic() > timeout && timer_delete(timer: &sclp_request_timer))
751 sclp_request_timer.function(&sclp_request_timer);
752 cpu_relax();
753 }
754 local_irq_disable();
755 local_ctl_load(0, &cr0);
756 if (!irq_context)
757 _local_bh_enable();
758 local_tick_enable(old_tick);
759 local_irq_restore(flags);
760
761 /* SYN2: Synchronous wait end (a=runstate, b=sync_count) */
762 sclp_trace(prio: 4, id: "SYN2", a: sclp_running_state, b: sync_count, err: false);
763}
764EXPORT_SYMBOL(sclp_sync_wait);
765
766/* Dispatch changes in send and receive mask to registered listeners. */
767static void
768sclp_dispatch_state_change(void)
769{
770 struct list_head *l;
771 struct sclp_register *reg;
772 unsigned long flags;
773 sccb_mask_t receive_mask;
774 sccb_mask_t send_mask;
775
776 do {
777 spin_lock_irqsave(&sclp_lock, flags);
778 reg = NULL;
779 list_for_each(l, &sclp_reg_list) {
780 reg = list_entry(l, struct sclp_register, list);
781 receive_mask = reg->send_mask & sclp_receive_mask;
782 send_mask = reg->receive_mask & sclp_send_mask;
783 if (reg->sclp_receive_mask != receive_mask ||
784 reg->sclp_send_mask != send_mask) {
785 reg->sclp_receive_mask = receive_mask;
786 reg->sclp_send_mask = send_mask;
787 break;
788 } else
789 reg = NULL;
790 }
791 spin_unlock_irqrestore(lock: &sclp_lock, flags);
792 if (reg && reg->state_change_fn) {
793 /* STCG: State-change callback (b=callback) */
794 sclp_trace(prio: 2, id: "STCG", a: 0, b: (u64)reg->state_change_fn,
795 err: false);
796
797 reg->state_change_fn(reg);
798 }
799 } while (reg);
800}
801
802struct sclp_statechangebuf {
803 struct evbuf_header header;
804 u8 validity_sclp_active_facility_mask : 1;
805 u8 validity_sclp_receive_mask : 1;
806 u8 validity_sclp_send_mask : 1;
807 u8 validity_read_data_function_mask : 1;
808 u16 _zeros : 12;
809 u16 mask_length;
810 u64 sclp_active_facility_mask;
811 u8 masks[2 * 1021 + 4]; /* variable length */
812 /*
813 * u8 sclp_receive_mask[mask_length];
814 * u8 sclp_send_mask[mask_length];
815 * u32 read_data_function_mask;
816 */
817} __attribute__((packed));
818
819
820/* State change event callback. Inform listeners of changes. */
821static void
822sclp_state_change_cb(struct evbuf_header *evbuf)
823{
824 unsigned long flags;
825 struct sclp_statechangebuf *scbuf;
826
827 BUILD_BUG_ON(sizeof(struct sclp_statechangebuf) > PAGE_SIZE);
828
829 scbuf = (struct sclp_statechangebuf *) evbuf;
830 spin_lock_irqsave(&sclp_lock, flags);
831 if (scbuf->validity_sclp_receive_mask)
832 sclp_receive_mask = sccb_get_recv_mask(scbuf);
833 if (scbuf->validity_sclp_send_mask)
834 sclp_send_mask = sccb_get_send_mask(scbuf);
835 spin_unlock_irqrestore(lock: &sclp_lock, flags);
836 if (scbuf->validity_sclp_active_facility_mask)
837 sclp.facilities = scbuf->sclp_active_facility_mask;
838 sclp_dispatch_state_change();
839}
840
841static struct sclp_register sclp_state_change_event = {
842 .receive_mask = EVTYP_STATECHANGE_MASK,
843 .receiver_fn = sclp_state_change_cb
844};
845
846/* Calculate receive and send mask of currently registered listeners.
847 * Called while sclp_lock is locked. */
848static inline void
849__sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
850{
851 struct list_head *l;
852 struct sclp_register *t;
853
854 *receive_mask = 0;
855 *send_mask = 0;
856 list_for_each(l, &sclp_reg_list) {
857 t = list_entry(l, struct sclp_register, list);
858 *receive_mask |= t->receive_mask;
859 *send_mask |= t->send_mask;
860 }
861}
862
863/* Register event listener. Return 0 on success, non-zero otherwise. */
864int
865sclp_register(struct sclp_register *reg)
866{
867 unsigned long flags;
868 sccb_mask_t receive_mask;
869 sccb_mask_t send_mask;
870 int rc;
871
872 /* REG: Event listener registered (b=caller) */
873 sclp_trace_register(prio: 2, id: "REG", a: 0, _RET_IP_, reg);
874
875 rc = sclp_init();
876 if (rc)
877 return rc;
878 spin_lock_irqsave(&sclp_lock, flags);
879 /* Check event mask for collisions */
880 __sclp_get_mask(receive_mask: &receive_mask, send_mask: &send_mask);
881 if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
882 spin_unlock_irqrestore(lock: &sclp_lock, flags);
883 return -EBUSY;
884 }
885 /* Trigger initial state change callback */
886 reg->sclp_receive_mask = 0;
887 reg->sclp_send_mask = 0;
888 list_add(new: &reg->list, head: &sclp_reg_list);
889 spin_unlock_irqrestore(lock: &sclp_lock, flags);
890 rc = sclp_init_mask(calculate: 1);
891 if (rc) {
892 spin_lock_irqsave(&sclp_lock, flags);
893 list_del(entry: &reg->list);
894 spin_unlock_irqrestore(lock: &sclp_lock, flags);
895 }
896 return rc;
897}
898
899EXPORT_SYMBOL(sclp_register);
900
901/* Unregister event listener. */
902void
903sclp_unregister(struct sclp_register *reg)
904{
905 unsigned long flags;
906
907 /* UREG: Event listener unregistered (b=caller) */
908 sclp_trace_register(prio: 2, id: "UREG", a: 0, _RET_IP_, reg);
909
910 spin_lock_irqsave(&sclp_lock, flags);
911 list_del(entry: &reg->list);
912 spin_unlock_irqrestore(lock: &sclp_lock, flags);
913 sclp_init_mask(calculate: 1);
914}
915
916EXPORT_SYMBOL(sclp_unregister);
917
918/* Remove event buffers which are marked processed. Return the number of
919 * remaining event buffers. */
920int
921sclp_remove_processed(struct sccb_header *sccb)
922{
923 struct evbuf_header *evbuf;
924 int unprocessed;
925 u16 remaining;
926
927 evbuf = (struct evbuf_header *) (sccb + 1);
928 unprocessed = 0;
929 remaining = sccb->length - sizeof(struct sccb_header);
930 while (remaining > 0) {
931 remaining -= evbuf->length;
932 if (evbuf->flags & 0x80) {
933 sccb->length -= evbuf->length;
934 memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
935 remaining);
936 } else {
937 unprocessed++;
938 evbuf = (struct evbuf_header *)
939 ((addr_t) evbuf + evbuf->length);
940 }
941 }
942 return unprocessed;
943}
944
945EXPORT_SYMBOL(sclp_remove_processed);
946
947/* Prepare init mask request. Called while sclp_lock is locked. */
948static inline void
949__sclp_make_init_req(sccb_mask_t receive_mask, sccb_mask_t send_mask)
950{
951 struct init_sccb *sccb = sclp_init_sccb;
952
953 clear_page(page: sccb);
954 memset(&sclp_init_req, 0, sizeof(struct sclp_req));
955 sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
956 sclp_init_req.status = SCLP_REQ_FILLED;
957 sclp_init_req.start_count = 0;
958 sclp_init_req.callback = NULL;
959 sclp_init_req.callback_data = NULL;
960 sclp_init_req.sccb = sccb;
961 sccb->header.length = sizeof(*sccb);
962 if (sclp_mask_compat_mode)
963 sccb->mask_length = SCLP_MASK_SIZE_COMPAT;
964 else
965 sccb->mask_length = sizeof(sccb_mask_t);
966 sccb_set_recv_mask(sccb, receive_mask);
967 sccb_set_send_mask(sccb, send_mask);
968 sccb_set_sclp_recv_mask(sccb, 0);
969 sccb_set_sclp_send_mask(sccb, 0);
970}
971
972/* Start init mask request. If calculate is non-zero, calculate the mask as
973 * requested by registered listeners. Use zero mask otherwise. Return 0 on
974 * success, non-zero otherwise. */
975static int
976sclp_init_mask(int calculate)
977{
978 unsigned long flags;
979 struct init_sccb *sccb = sclp_init_sccb;
980 sccb_mask_t receive_mask;
981 sccb_mask_t send_mask;
982 int retry;
983 int rc;
984 unsigned long wait;
985
986 spin_lock_irqsave(&sclp_lock, flags);
987 /* Check if interface is in appropriate state */
988 if (sclp_mask_state != sclp_mask_state_idle) {
989 spin_unlock_irqrestore(lock: &sclp_lock, flags);
990 return -EBUSY;
991 }
992 if (sclp_activation_state == sclp_activation_state_inactive) {
993 spin_unlock_irqrestore(lock: &sclp_lock, flags);
994 return -EINVAL;
995 }
996 sclp_mask_state = sclp_mask_state_initializing;
997 /* Determine mask */
998 if (calculate)
999 __sclp_get_mask(receive_mask: &receive_mask, send_mask: &send_mask);
1000 else {
1001 receive_mask = 0;
1002 send_mask = 0;
1003 }
1004 rc = -EIO;
1005 for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
1006 /* Prepare request */
1007 __sclp_make_init_req(receive_mask, send_mask);
1008 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1009 if (sclp_add_request(&sclp_init_req)) {
1010 /* Try again later */
1011 wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
1012 while (time_before(jiffies, wait))
1013 sclp_sync_wait();
1014 spin_lock_irqsave(&sclp_lock, flags);
1015 continue;
1016 }
1017 while (sclp_init_req.status != SCLP_REQ_DONE &&
1018 sclp_init_req.status != SCLP_REQ_FAILED)
1019 sclp_sync_wait();
1020 spin_lock_irqsave(&sclp_lock, flags);
1021 if (sclp_init_req.status == SCLP_REQ_DONE &&
1022 sccb->header.response_code == 0x20) {
1023 /* Successful request */
1024 if (calculate) {
1025 sclp_receive_mask = sccb_get_sclp_recv_mask(sccb);
1026 sclp_send_mask = sccb_get_sclp_send_mask(sccb);
1027 } else {
1028 sclp_receive_mask = 0;
1029 sclp_send_mask = 0;
1030 }
1031 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1032 sclp_dispatch_state_change();
1033 spin_lock_irqsave(&sclp_lock, flags);
1034 rc = 0;
1035 break;
1036 }
1037 }
1038 sclp_mask_state = sclp_mask_state_idle;
1039 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1040 return rc;
1041}
1042
1043/* Deactivate SCLP interface. On success, new requests will be rejected,
1044 * events will no longer be dispatched. Return 0 on success, non-zero
1045 * otherwise. */
1046int
1047sclp_deactivate(void)
1048{
1049 unsigned long flags;
1050 int rc;
1051
1052 spin_lock_irqsave(&sclp_lock, flags);
1053 /* Deactivate can only be called when active */
1054 if (sclp_activation_state != sclp_activation_state_active) {
1055 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1056 return -EINVAL;
1057 }
1058 sclp_activation_state = sclp_activation_state_deactivating;
1059 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1060 rc = sclp_init_mask(calculate: 0);
1061 spin_lock_irqsave(&sclp_lock, flags);
1062 if (rc == 0)
1063 sclp_activation_state = sclp_activation_state_inactive;
1064 else
1065 sclp_activation_state = sclp_activation_state_active;
1066 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1067 return rc;
1068}
1069
1070EXPORT_SYMBOL(sclp_deactivate);
1071
1072/* Reactivate SCLP interface after sclp_deactivate. On success, new
1073 * requests will be accepted, events will be dispatched again. Return 0 on
1074 * success, non-zero otherwise. */
1075int
1076sclp_reactivate(void)
1077{
1078 unsigned long flags;
1079 int rc;
1080
1081 spin_lock_irqsave(&sclp_lock, flags);
1082 /* Reactivate can only be called when inactive */
1083 if (sclp_activation_state != sclp_activation_state_inactive) {
1084 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1085 return -EINVAL;
1086 }
1087 sclp_activation_state = sclp_activation_state_activating;
1088 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1089 rc = sclp_init_mask(calculate: 1);
1090 spin_lock_irqsave(&sclp_lock, flags);
1091 if (rc == 0)
1092 sclp_activation_state = sclp_activation_state_active;
1093 else
1094 sclp_activation_state = sclp_activation_state_inactive;
1095 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1096 return rc;
1097}
1098
1099EXPORT_SYMBOL(sclp_reactivate);
1100
1101/* Handler for external interruption used during initialization. Modify
1102 * request state to done. */
1103static void sclp_check_handler(struct ext_code ext_code,
1104 unsigned int param32, unsigned long param64)
1105{
1106 u32 finished_sccb;
1107
1108 inc_irq_stat(IRQEXT_SCP);
1109 finished_sccb = param32 & 0xfffffff8;
1110 /* Is this the interrupt we are waiting for? */
1111 if (finished_sccb == 0)
1112 return;
1113 if (finished_sccb != __pa(sclp_init_sccb))
1114 panic(fmt: "sclp: unsolicited interrupt for buffer at 0x%x\n",
1115 finished_sccb);
1116 spin_lock(lock: &sclp_lock);
1117 if (sclp_running_state == sclp_running_state_running) {
1118 sclp_init_req.status = SCLP_REQ_DONE;
1119 sclp_running_state = sclp_running_state_idle;
1120 }
1121 spin_unlock(lock: &sclp_lock);
1122}
1123
1124/* Initial init mask request timed out. Modify request state to failed. */
1125static void
1126sclp_check_timeout(struct timer_list *unused)
1127{
1128 unsigned long flags;
1129
1130 spin_lock_irqsave(&sclp_lock, flags);
1131 if (sclp_running_state == sclp_running_state_running) {
1132 sclp_init_req.status = SCLP_REQ_FAILED;
1133 sclp_running_state = sclp_running_state_idle;
1134 }
1135 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1136}
1137
1138/* Perform a check of the SCLP interface. Return zero if the interface is
1139 * available and there are no pending requests from a previous instance.
1140 * Return non-zero otherwise. */
1141static int
1142sclp_check_interface(void)
1143{
1144 struct init_sccb *sccb;
1145 unsigned long flags;
1146 int retry;
1147 int rc;
1148
1149 spin_lock_irqsave(&sclp_lock, flags);
1150 /* Prepare init mask command */
1151 rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
1152 if (rc) {
1153 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1154 return rc;
1155 }
1156 for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
1157 __sclp_make_init_req(receive_mask: 0, send_mask: 0);
1158 sccb = (struct init_sccb *) sclp_init_req.sccb;
1159 rc = sclp_service_call_trace(command: sclp_init_req.command, sccb);
1160 if (rc == -EIO)
1161 break;
1162 sclp_init_req.status = SCLP_REQ_RUNNING;
1163 sclp_running_state = sclp_running_state_running;
1164 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
1165 cb: sclp_check_timeout);
1166 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1167 /* Enable service-signal interruption - needs to happen
1168 * with IRQs enabled. */
1169 irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1170 /* Wait for signal from interrupt or timeout */
1171 sclp_sync_wait();
1172 /* Disable service-signal interruption - needs to happen
1173 * with IRQs enabled. */
1174 irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
1175 spin_lock_irqsave(&sclp_lock, flags);
1176 timer_delete(timer: &sclp_request_timer);
1177 rc = -EBUSY;
1178 if (sclp_init_req.status == SCLP_REQ_DONE) {
1179 if (sccb->header.response_code == 0x20) {
1180 rc = 0;
1181 break;
1182 } else if (sccb->header.response_code == 0x74f0) {
1183 if (!sclp_mask_compat_mode) {
1184 sclp_mask_compat_mode = true;
1185 retry = 0;
1186 }
1187 }
1188 }
1189 }
1190 unregister_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
1191 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1192 return rc;
1193}
1194
1195/* Reboot event handler. Reset send and receive mask to prevent pending SCLP
1196 * events from interfering with rebooted system. */
1197static int
1198sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
1199{
1200 sclp_deactivate();
1201 return NOTIFY_DONE;
1202}
1203
1204static struct notifier_block sclp_reboot_notifier = {
1205 .notifier_call = sclp_reboot_event,
1206 .priority = INT_MIN,
1207};
1208
1209static ssize_t con_pages_show(struct device_driver *dev, char *buf)
1210{
1211 return sysfs_emit(buf, fmt: "%i\n", sclp_console_pages);
1212}
1213
1214static DRIVER_ATTR_RO(con_pages);
1215
1216static ssize_t con_drop_store(struct device_driver *dev, const char *buf, size_t count)
1217{
1218 int rc;
1219
1220 rc = kstrtobool(s: buf, res: &sclp_console_drop);
1221 return rc ?: count;
1222}
1223
1224static ssize_t con_drop_show(struct device_driver *dev, char *buf)
1225{
1226 return sysfs_emit(buf, fmt: "%i\n", sclp_console_drop);
1227}
1228
1229static DRIVER_ATTR_RW(con_drop);
1230
1231static ssize_t con_full_show(struct device_driver *dev, char *buf)
1232{
1233 return sysfs_emit(buf, fmt: "%lu\n", sclp_console_full);
1234}
1235
1236static DRIVER_ATTR_RO(con_full);
1237
1238static struct attribute *sclp_drv_attrs[] = {
1239 &driver_attr_con_pages.attr,
1240 &driver_attr_con_drop.attr,
1241 &driver_attr_con_full.attr,
1242 NULL,
1243};
1244static struct attribute_group sclp_drv_attr_group = {
1245 .attrs = sclp_drv_attrs,
1246};
1247static const struct attribute_group *sclp_drv_attr_groups[] = {
1248 &sclp_drv_attr_group,
1249 NULL,
1250};
1251
1252static struct platform_driver sclp_pdrv = {
1253 .driver = {
1254 .name = "sclp",
1255 .groups = sclp_drv_attr_groups,
1256 },
1257};
1258
1259/* Initialize SCLP driver. Return zero if driver is operational, non-zero
1260 * otherwise. */
1261int sclp_init(void)
1262{
1263 unsigned long flags;
1264 int rc = 0;
1265
1266 spin_lock_irqsave(&sclp_lock, flags);
1267 /* Check for previous or running initialization */
1268 if (sclp_init_state != sclp_init_state_uninitialized)
1269 goto fail_unlock;
1270 sclp_init_state = sclp_init_state_initializing;
1271 sclp_read_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
1272 sclp_init_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
1273 BUG_ON(!sclp_read_sccb || !sclp_init_sccb);
1274 /* Set up variables */
1275 list_add(new: &sclp_state_change_event.list, head: &sclp_reg_list);
1276 timer_setup(&sclp_request_timer, NULL, 0);
1277 timer_setup(&sclp_queue_timer, sclp_req_queue_timeout, 0);
1278 /* Check interface */
1279 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1280 rc = sclp_check_interface();
1281 spin_lock_irqsave(&sclp_lock, flags);
1282 if (rc)
1283 goto fail_init_state_uninitialized;
1284 /* Register reboot handler */
1285 rc = register_reboot_notifier(&sclp_reboot_notifier);
1286 if (rc)
1287 goto fail_init_state_uninitialized;
1288 /* Register interrupt handler */
1289 rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_interrupt_handler);
1290 if (rc)
1291 goto fail_unregister_reboot_notifier;
1292 sclp_init_state = sclp_init_state_initialized;
1293 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1294 /* Enable service-signal external interruption - needs to happen with
1295 * IRQs enabled. */
1296 irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1297 sclp_init_mask(calculate: 1);
1298 return 0;
1299
1300fail_unregister_reboot_notifier:
1301 unregister_reboot_notifier(&sclp_reboot_notifier);
1302fail_init_state_uninitialized:
1303 list_del(entry: &sclp_state_change_event.list);
1304 sclp_init_state = sclp_init_state_uninitialized;
1305 free_page((unsigned long) sclp_read_sccb);
1306 free_page((unsigned long) sclp_init_sccb);
1307fail_unlock:
1308 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1309 return rc;
1310}
1311
1312static __init int sclp_initcall(void)
1313{
1314 return platform_driver_register(&sclp_pdrv);
1315}
1316
1317arch_initcall(sclp_initcall);
1318

source code of linux/drivers/s390/char/sclp.c