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/module.h>
13#include <linux/err.h>
14#include <linux/panic_notifier.h>
15#include <linux/spinlock.h>
16#include <linux/interrupt.h>
17#include <linux/timer.h>
18#include <linux/reboot.h>
19#include <linux/jiffies.h>
20#include <linux/init.h>
21#include <linux/platform_device.h>
22#include <asm/types.h>
23#include <asm/irq.h>
24#include <asm/debug.h>
25
26#include "sclp.h"
27
28#define SCLP_HEADER "sclp: "
29
30struct sclp_trace_entry {
31 char id[4] __nonstring;
32 u32 a;
33 u64 b;
34};
35
36#define SCLP_TRACE_ENTRY_SIZE sizeof(struct sclp_trace_entry)
37#define SCLP_TRACE_MAX_SIZE 128
38#define SCLP_TRACE_EVENT_MAX_SIZE 64
39
40/* Debug trace area intended for all entries in abbreviated form. */
41DEFINE_STATIC_DEBUG_INFO(sclp_debug, "sclp", 8, 1, SCLP_TRACE_ENTRY_SIZE,
42 &debug_hex_ascii_view);
43
44/* Error trace area intended for full entries relating to failed requests. */
45DEFINE_STATIC_DEBUG_INFO(sclp_debug_err, "sclp_err", 4, 1,
46 SCLP_TRACE_ENTRY_SIZE, &debug_hex_ascii_view);
47
48/* Lock to protect internal data consistency. */
49static DEFINE_SPINLOCK(sclp_lock);
50
51/* Mask of events that we can send to the sclp interface. */
52static sccb_mask_t sclp_receive_mask;
53
54/* Mask of events that we can receive from the sclp interface. */
55static sccb_mask_t sclp_send_mask;
56
57/* List of registered event listeners and senders. */
58static LIST_HEAD(sclp_reg_list);
59
60/* List of queued requests. */
61static LIST_HEAD(sclp_req_queue);
62
63/* Data for read and init requests. */
64static struct sclp_req sclp_read_req;
65static struct sclp_req sclp_init_req;
66static void *sclp_read_sccb;
67static struct init_sccb *sclp_init_sccb;
68
69/* Number of console pages to allocate, used by sclp_con.c and sclp_vt220.c */
70int sclp_console_pages = SCLP_CONSOLE_PAGES;
71/* Flag to indicate if buffer pages are dropped on buffer full condition */
72bool sclp_console_drop = true;
73/* Number of times the console dropped buffer pages */
74unsigned long sclp_console_full;
75
76/* The currently active SCLP command word. */
77static sclp_cmdw_t active_cmd;
78
79static inline void sclp_trace(int prio, char *id, u32 a, u64 b, bool err)
80{
81 struct sclp_trace_entry e;
82
83 memset(&e, 0, sizeof(e));
84 strtomem(e.id, id);
85 e.a = a;
86 e.b = b;
87 debug_event(&sclp_debug, prio, &e, sizeof(e));
88 if (err)
89 debug_event(&sclp_debug_err, 0, &e, sizeof(e));
90}
91
92static inline int no_zeroes_len(void *data, int len)
93{
94 char *d = data;
95
96 /* Minimize trace area usage by not tracing trailing zeroes. */
97 while (len > SCLP_TRACE_ENTRY_SIZE && d[len - 1] == 0)
98 len--;
99
100 return len;
101}
102
103static inline void sclp_trace_bin(int prio, void *d, int len, int errlen)
104{
105 debug_event(&sclp_debug, prio, d, no_zeroes_len(data: d, len));
106 if (errlen)
107 debug_event(&sclp_debug_err, 0, d, no_zeroes_len(data: d, len: errlen));
108}
109
110static inline int abbrev_len(sclp_cmdw_t cmd, struct sccb_header *sccb)
111{
112 struct evbuf_header *evbuf = (struct evbuf_header *)(sccb + 1);
113 int len = sccb->length, limit = SCLP_TRACE_MAX_SIZE;
114
115 /* Full SCCB tracing if debug level is set to max. */
116 if (sclp_debug.level == DEBUG_MAX_LEVEL)
117 return len;
118
119 /* Minimal tracing for console writes. */
120 if (cmd == SCLP_CMDW_WRITE_EVENT_DATA &&
121 (evbuf->type == EVTYP_MSG || evbuf->type == EVTYP_VT220MSG))
122 limit = SCLP_TRACE_ENTRY_SIZE;
123
124 return min(len, limit);
125}
126
127static inline void sclp_trace_sccb(int prio, char *id, u32 a, u64 b,
128 sclp_cmdw_t cmd, struct sccb_header *sccb,
129 bool err)
130{
131 sclp_trace(prio, id, a, b, err);
132 if (sccb) {
133 sclp_trace_bin(prio: prio + 1, d: sccb, len: abbrev_len(cmd, sccb),
134 errlen: err ? sccb->length : 0);
135 }
136}
137
138static inline void sclp_trace_evbuf(int prio, char *id, u32 a, u64 b,
139 struct evbuf_header *evbuf, bool err)
140{
141 sclp_trace(prio, id, a, b, err);
142 sclp_trace_bin(prio: prio + 1, d: evbuf,
143 min((int)evbuf->length, (int)SCLP_TRACE_EVENT_MAX_SIZE),
144 errlen: err ? evbuf->length : 0);
145}
146
147static inline void sclp_trace_req(int prio, char *id, struct sclp_req *req,
148 bool err)
149{
150 struct sccb_header *sccb = req->sccb;
151 union {
152 struct {
153 u16 status;
154 u16 response;
155 u16 timeout;
156 u16 start_count;
157 };
158 u64 b;
159 } summary;
160
161 summary.status = req->status;
162 summary.response = sccb ? sccb->response_code : 0;
163 summary.timeout = (u16)req->queue_timeout;
164 summary.start_count = (u16)req->start_count;
165
166 sclp_trace(prio, id, __pa(sccb), b: summary.b, err);
167}
168
169static inline void sclp_trace_register(int prio, char *id, u32 a, u64 b,
170 struct sclp_register *reg)
171{
172 struct {
173 u64 receive;
174 u64 send;
175 } d;
176
177 d.receive = reg->receive_mask;
178 d.send = reg->send_mask;
179
180 sclp_trace(prio, id, a, b, err: false);
181 sclp_trace_bin(prio, d: &d, len: sizeof(d), errlen: 0);
182}
183
184static int __init sclp_setup_console_pages(char *str)
185{
186 int pages, rc;
187
188 rc = kstrtoint(s: str, base: 0, res: &pages);
189 if (!rc && pages >= SCLP_CONSOLE_PAGES)
190 sclp_console_pages = pages;
191 return 1;
192}
193
194__setup("sclp_con_pages=", sclp_setup_console_pages);
195
196static int __init sclp_setup_console_drop(char *str)
197{
198 return kstrtobool(s: str, res: &sclp_console_drop) == 0;
199}
200
201__setup("sclp_con_drop=", sclp_setup_console_drop);
202
203/* Timer for request retries. */
204static struct timer_list sclp_request_timer;
205
206/* Timer for queued requests. */
207static struct timer_list sclp_queue_timer;
208
209/* Internal state: is a request active at the sclp? */
210static volatile enum sclp_running_state_t {
211 sclp_running_state_idle,
212 sclp_running_state_running,
213 sclp_running_state_reset_pending
214} sclp_running_state = sclp_running_state_idle;
215
216/* Internal state: is a read request pending? */
217static volatile enum sclp_reading_state_t {
218 sclp_reading_state_idle,
219 sclp_reading_state_reading
220} sclp_reading_state = sclp_reading_state_idle;
221
222/* Internal state: is the driver currently serving requests? */
223static volatile enum sclp_activation_state_t {
224 sclp_activation_state_active,
225 sclp_activation_state_deactivating,
226 sclp_activation_state_inactive,
227 sclp_activation_state_activating
228} sclp_activation_state = sclp_activation_state_active;
229
230/* Internal state: is an init mask request pending? */
231static volatile enum sclp_mask_state_t {
232 sclp_mask_state_idle,
233 sclp_mask_state_initializing
234} sclp_mask_state = sclp_mask_state_idle;
235
236/* Maximum retry counts */
237#define SCLP_INIT_RETRY 3
238#define SCLP_MASK_RETRY 3
239
240/* Timeout intervals in seconds.*/
241#define SCLP_BUSY_INTERVAL 10
242#define SCLP_RETRY_INTERVAL 30
243
244static void sclp_request_timeout(bool force_restart);
245static void sclp_process_queue(void);
246static void __sclp_make_read_req(void);
247static int sclp_init_mask(int calculate);
248static int sclp_init(void);
249
250static void
251__sclp_queue_read_req(void)
252{
253 if (sclp_reading_state == sclp_reading_state_idle) {
254 sclp_reading_state = sclp_reading_state_reading;
255 __sclp_make_read_req();
256 /* Add request to head of queue */
257 list_add(new: &sclp_read_req.list, head: &sclp_req_queue);
258 }
259}
260
261/* Set up request retry timer. Called while sclp_lock is locked. */
262static inline void
263__sclp_set_request_timer(unsigned long time, void (*cb)(struct timer_list *))
264{
265 del_timer(timer: &sclp_request_timer);
266 sclp_request_timer.function = cb;
267 sclp_request_timer.expires = jiffies + time;
268 add_timer(timer: &sclp_request_timer);
269}
270
271static void sclp_request_timeout_restart(struct timer_list *unused)
272{
273 sclp_request_timeout(force_restart: true);
274}
275
276static void sclp_request_timeout_normal(struct timer_list *unused)
277{
278 sclp_request_timeout(force_restart: false);
279}
280
281/* Request timeout handler. Restart the request queue. If force_restart,
282 * force restart of running request. */
283static void sclp_request_timeout(bool force_restart)
284{
285 unsigned long flags;
286
287 /* TMO: A timeout occurred (a=force_restart) */
288 sclp_trace(prio: 2, id: "TMO", a: force_restart, b: 0, err: true);
289
290 spin_lock_irqsave(&sclp_lock, flags);
291 if (force_restart) {
292 if (sclp_running_state == sclp_running_state_running) {
293 /* Break running state and queue NOP read event request
294 * to get a defined interface state. */
295 __sclp_queue_read_req();
296 sclp_running_state = sclp_running_state_idle;
297 }
298 } else {
299 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
300 cb: sclp_request_timeout_normal);
301 }
302 spin_unlock_irqrestore(lock: &sclp_lock, flags);
303 sclp_process_queue();
304}
305
306/*
307 * Returns the expire value in jiffies of the next pending request timeout,
308 * if any. Needs to be called with sclp_lock.
309 */
310static unsigned long __sclp_req_queue_find_next_timeout(void)
311{
312 unsigned long expires_next = 0;
313 struct sclp_req *req;
314
315 list_for_each_entry(req, &sclp_req_queue, list) {
316 if (!req->queue_expires)
317 continue;
318 if (!expires_next ||
319 (time_before(req->queue_expires, expires_next)))
320 expires_next = req->queue_expires;
321 }
322 return expires_next;
323}
324
325/*
326 * Returns expired request, if any, and removes it from the list.
327 */
328static struct sclp_req *__sclp_req_queue_remove_expired_req(void)
329{
330 unsigned long flags, now;
331 struct sclp_req *req;
332
333 spin_lock_irqsave(&sclp_lock, flags);
334 now = jiffies;
335 /* Don't need list_for_each_safe because we break out after list_del */
336 list_for_each_entry(req, &sclp_req_queue, list) {
337 if (!req->queue_expires)
338 continue;
339 if (time_before_eq(req->queue_expires, now)) {
340 if (req->status == SCLP_REQ_QUEUED) {
341 req->status = SCLP_REQ_QUEUED_TIMEOUT;
342 list_del(entry: &req->list);
343 goto out;
344 }
345 }
346 }
347 req = NULL;
348out:
349 spin_unlock_irqrestore(lock: &sclp_lock, flags);
350 return req;
351}
352
353/*
354 * Timeout handler for queued requests. Removes request from list and
355 * invokes callback. This timer can be set per request in situations where
356 * waiting too long would be harmful to the system, e.g. during SE reboot.
357 */
358static void sclp_req_queue_timeout(struct timer_list *unused)
359{
360 unsigned long flags, expires_next;
361 struct sclp_req *req;
362
363 do {
364 req = __sclp_req_queue_remove_expired_req();
365
366 if (req) {
367 /* RQTM: Request timed out (a=sccb, b=summary) */
368 sclp_trace_req(prio: 2, id: "RQTM", req, err: true);
369 }
370
371 if (req && req->callback)
372 req->callback(req, req->callback_data);
373 } while (req);
374
375 spin_lock_irqsave(&sclp_lock, flags);
376 expires_next = __sclp_req_queue_find_next_timeout();
377 if (expires_next)
378 mod_timer(timer: &sclp_queue_timer, expires: expires_next);
379 spin_unlock_irqrestore(lock: &sclp_lock, flags);
380}
381
382static int sclp_service_call_trace(sclp_cmdw_t command, void *sccb)
383{
384 static u64 srvc_count;
385 int rc;
386
387 /* SRV1: Service call about to be issued (a=command, b=sccb address) */
388 sclp_trace_sccb(prio: 0, id: "SRV1", a: command, b: (u64)sccb, cmd: command, sccb, err: false);
389
390 rc = sclp_service_call(command, sccb);
391
392 /* SRV2: Service call was issued (a=rc, b=SRVC sequence number) */
393 sclp_trace(prio: 0, id: "SRV2", a: -rc, b: ++srvc_count, err: rc != 0);
394
395 if (rc == 0)
396 active_cmd = command;
397
398 return rc;
399}
400
401/* Try to start a request. Return zero if the request was successfully
402 * started or if it will be started at a later time. Return non-zero otherwise.
403 * Called while sclp_lock is locked. */
404static int
405__sclp_start_request(struct sclp_req *req)
406{
407 int rc;
408
409 if (sclp_running_state != sclp_running_state_idle)
410 return 0;
411 del_timer(timer: &sclp_request_timer);
412 rc = sclp_service_call_trace(command: req->command, sccb: req->sccb);
413 req->start_count++;
414
415 if (rc == 0) {
416 /* Successfully started request */
417 req->status = SCLP_REQ_RUNNING;
418 sclp_running_state = sclp_running_state_running;
419 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
420 cb: sclp_request_timeout_restart);
421 return 0;
422 } else if (rc == -EBUSY) {
423 /* Try again later */
424 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
425 cb: sclp_request_timeout_normal);
426 return 0;
427 }
428 /* Request failed */
429 req->status = SCLP_REQ_FAILED;
430 return rc;
431}
432
433/* Try to start queued requests. */
434static void
435sclp_process_queue(void)
436{
437 struct sclp_req *req;
438 int rc;
439 unsigned long flags;
440
441 spin_lock_irqsave(&sclp_lock, flags);
442 if (sclp_running_state != sclp_running_state_idle) {
443 spin_unlock_irqrestore(lock: &sclp_lock, flags);
444 return;
445 }
446 del_timer(timer: &sclp_request_timer);
447 while (!list_empty(head: &sclp_req_queue)) {
448 req = list_entry(sclp_req_queue.next, struct sclp_req, list);
449 rc = __sclp_start_request(req);
450 if (rc == 0)
451 break;
452 /* Request failed */
453 if (req->start_count > 1) {
454 /* Cannot abort already submitted request - could still
455 * be active at the SCLP */
456 __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ,
457 cb: sclp_request_timeout_normal);
458 break;
459 }
460 /* Post-processing for aborted request */
461 list_del(entry: &req->list);
462
463 /* RQAB: Request aborted (a=sccb, b=summary) */
464 sclp_trace_req(prio: 2, id: "RQAB", req, err: true);
465
466 if (req->callback) {
467 spin_unlock_irqrestore(lock: &sclp_lock, flags);
468 req->callback(req, req->callback_data);
469 spin_lock_irqsave(&sclp_lock, flags);
470 }
471 }
472 spin_unlock_irqrestore(lock: &sclp_lock, flags);
473}
474
475static int __sclp_can_add_request(struct sclp_req *req)
476{
477 if (req == &sclp_init_req)
478 return 1;
479 if (sclp_init_state != sclp_init_state_initialized)
480 return 0;
481 if (sclp_activation_state != sclp_activation_state_active)
482 return 0;
483 return 1;
484}
485
486/* Queue a new request. Return zero on success, non-zero otherwise. */
487int
488sclp_add_request(struct sclp_req *req)
489{
490 unsigned long flags;
491 int rc;
492
493 spin_lock_irqsave(&sclp_lock, flags);
494 if (!__sclp_can_add_request(req)) {
495 spin_unlock_irqrestore(lock: &sclp_lock, flags);
496 return -EIO;
497 }
498
499 /* RQAD: Request was added (a=sccb, b=caller) */
500 sclp_trace(prio: 2, id: "RQAD", __pa(req->sccb), _RET_IP_, err: false);
501
502 req->status = SCLP_REQ_QUEUED;
503 req->start_count = 0;
504 list_add_tail(new: &req->list, head: &sclp_req_queue);
505 rc = 0;
506 if (req->queue_timeout) {
507 req->queue_expires = jiffies + req->queue_timeout * HZ;
508 if (!timer_pending(timer: &sclp_queue_timer) ||
509 time_after(sclp_queue_timer.expires, req->queue_expires))
510 mod_timer(timer: &sclp_queue_timer, expires: req->queue_expires);
511 } else
512 req->queue_expires = 0;
513 /* Start if request is first in list */
514 if (sclp_running_state == sclp_running_state_idle &&
515 req->list.prev == &sclp_req_queue) {
516 rc = __sclp_start_request(req);
517 if (rc)
518 list_del(entry: &req->list);
519 }
520 spin_unlock_irqrestore(lock: &sclp_lock, flags);
521 return rc;
522}
523
524EXPORT_SYMBOL(sclp_add_request);
525
526/* Dispatch events found in request buffer to registered listeners. Return 0
527 * if all events were dispatched, non-zero otherwise. */
528static int
529sclp_dispatch_evbufs(struct sccb_header *sccb)
530{
531 unsigned long flags;
532 struct evbuf_header *evbuf;
533 struct list_head *l;
534 struct sclp_register *reg;
535 int offset;
536 int rc;
537
538 spin_lock_irqsave(&sclp_lock, flags);
539 rc = 0;
540 for (offset = sizeof(struct sccb_header); offset < sccb->length;
541 offset += evbuf->length) {
542 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
543 /* Check for malformed hardware response */
544 if (evbuf->length == 0)
545 break;
546 /* Search for event handler */
547 reg = NULL;
548 list_for_each(l, &sclp_reg_list) {
549 reg = list_entry(l, struct sclp_register, list);
550 if (reg->receive_mask & SCLP_EVTYP_MASK(evbuf->type))
551 break;
552 else
553 reg = NULL;
554 }
555
556 /* EVNT: Event callback (b=receiver) */
557 sclp_trace_evbuf(prio: 2, id: "EVNT", a: 0, b: reg ? (u64)reg->receiver_fn : 0,
558 evbuf, err: !reg);
559
560 if (reg && reg->receiver_fn) {
561 spin_unlock_irqrestore(lock: &sclp_lock, flags);
562 reg->receiver_fn(evbuf);
563 spin_lock_irqsave(&sclp_lock, flags);
564 } else if (reg == NULL)
565 rc = -EOPNOTSUPP;
566 }
567 spin_unlock_irqrestore(lock: &sclp_lock, flags);
568 return rc;
569}
570
571/* Read event data request callback. */
572static void
573sclp_read_cb(struct sclp_req *req, void *data)
574{
575 unsigned long flags;
576 struct sccb_header *sccb;
577
578 sccb = (struct sccb_header *) req->sccb;
579 if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 ||
580 sccb->response_code == 0x220))
581 sclp_dispatch_evbufs(sccb);
582 spin_lock_irqsave(&sclp_lock, flags);
583 sclp_reading_state = sclp_reading_state_idle;
584 spin_unlock_irqrestore(lock: &sclp_lock, flags);
585}
586
587/* Prepare read event data request. Called while sclp_lock is locked. */
588static void __sclp_make_read_req(void)
589{
590 struct sccb_header *sccb;
591
592 sccb = (struct sccb_header *) sclp_read_sccb;
593 clear_page(page: sccb);
594 memset(&sclp_read_req, 0, sizeof(struct sclp_req));
595 sclp_read_req.command = SCLP_CMDW_READ_EVENT_DATA;
596 sclp_read_req.status = SCLP_REQ_QUEUED;
597 sclp_read_req.start_count = 0;
598 sclp_read_req.callback = sclp_read_cb;
599 sclp_read_req.sccb = sccb;
600 sccb->length = PAGE_SIZE;
601 sccb->function_code = 0;
602 sccb->control_mask[2] = 0x80;
603}
604
605/* Search request list for request with matching sccb. Return request if found,
606 * NULL otherwise. Called while sclp_lock is locked. */
607static inline struct sclp_req *
608__sclp_find_req(u32 sccb)
609{
610 struct list_head *l;
611 struct sclp_req *req;
612
613 list_for_each(l, &sclp_req_queue) {
614 req = list_entry(l, struct sclp_req, list);
615 if (sccb == __pa(req->sccb))
616 return req;
617 }
618 return NULL;
619}
620
621static bool ok_response(u32 sccb_int, sclp_cmdw_t cmd)
622{
623 struct sccb_header *sccb = (struct sccb_header *)__va(sccb_int);
624 struct evbuf_header *evbuf;
625 u16 response;
626
627 if (!sccb)
628 return true;
629
630 /* Check SCCB response. */
631 response = sccb->response_code & 0xff;
632 if (response != 0x10 && response != 0x20)
633 return false;
634
635 /* Check event-processed flag on outgoing events. */
636 if (cmd == SCLP_CMDW_WRITE_EVENT_DATA) {
637 evbuf = (struct evbuf_header *)(sccb + 1);
638 if (!(evbuf->flags & 0x80))
639 return false;
640 }
641
642 return true;
643}
644
645/* Handler for external interruption. Perform request post-processing.
646 * Prepare read event data request if necessary. Start processing of next
647 * request on queue. */
648static void sclp_interrupt_handler(struct ext_code ext_code,
649 unsigned int param32, unsigned long param64)
650{
651 struct sclp_req *req;
652 u32 finished_sccb;
653 u32 evbuf_pending;
654
655 inc_irq_stat(IRQEXT_SCP);
656 spin_lock(lock: &sclp_lock);
657 finished_sccb = param32 & 0xfffffff8;
658 evbuf_pending = param32 & 0x3;
659
660 /* INT: Interrupt received (a=intparm, b=cmd) */
661 sclp_trace_sccb(prio: 0, id: "INT", a: param32, b: active_cmd, cmd: active_cmd,
662 sccb: (struct sccb_header *)__va(finished_sccb),
663 err: !ok_response(sccb_int: finished_sccb, cmd: active_cmd));
664
665 if (finished_sccb) {
666 del_timer(timer: &sclp_request_timer);
667 sclp_running_state = sclp_running_state_reset_pending;
668 req = __sclp_find_req(sccb: finished_sccb);
669 if (req) {
670 /* Request post-processing */
671 list_del(entry: &req->list);
672 req->status = SCLP_REQ_DONE;
673
674 /* RQOK: Request success (a=sccb, b=summary) */
675 sclp_trace_req(prio: 2, id: "RQOK", req, err: false);
676
677 if (req->callback) {
678 spin_unlock(lock: &sclp_lock);
679 req->callback(req, req->callback_data);
680 spin_lock(lock: &sclp_lock);
681 }
682 } else {
683 /* UNEX: Unexpected SCCB completion (a=sccb address) */
684 sclp_trace(prio: 0, id: "UNEX", a: finished_sccb, b: 0, err: true);
685 }
686 sclp_running_state = sclp_running_state_idle;
687 active_cmd = 0;
688 }
689 if (evbuf_pending &&
690 sclp_activation_state == sclp_activation_state_active)
691 __sclp_queue_read_req();
692 spin_unlock(lock: &sclp_lock);
693 sclp_process_queue();
694}
695
696/* Convert interval in jiffies to TOD ticks. */
697static inline u64
698sclp_tod_from_jiffies(unsigned long jiffies)
699{
700 return (u64) (jiffies / HZ) << 32;
701}
702
703/* Wait until a currently running request finished. Note: while this function
704 * is running, no timers are served on the calling CPU. */
705void
706sclp_sync_wait(void)
707{
708 unsigned long long old_tick;
709 struct ctlreg cr0, cr0_sync;
710 unsigned long flags;
711 static u64 sync_count;
712 u64 timeout;
713 int irq_context;
714
715 /* SYN1: Synchronous wait start (a=runstate, b=sync count) */
716 sclp_trace(prio: 4, id: "SYN1", a: sclp_running_state, b: ++sync_count, err: false);
717
718 /* We'll be disabling timer interrupts, so we need a custom timeout
719 * mechanism */
720 timeout = 0;
721 if (timer_pending(timer: &sclp_request_timer)) {
722 /* Get timeout TOD value */
723 timeout = get_tod_clock_fast() +
724 sclp_tod_from_jiffies(jiffies: sclp_request_timer.expires -
725 jiffies);
726 }
727 local_irq_save(flags);
728 /* Prevent bottom half from executing once we force interrupts open */
729 irq_context = in_interrupt();
730 if (!irq_context)
731 local_bh_disable();
732 /* Enable service-signal interruption, disable timer interrupts */
733 old_tick = local_tick_disable();
734 trace_hardirqs_on();
735 local_ctl_store(0, &cr0);
736 cr0_sync.val = cr0.val & ~CR0_IRQ_SUBCLASS_MASK;
737 cr0_sync.val |= 1UL << (63 - 54);
738 local_ctl_load(0, &cr0_sync);
739 __arch_local_irq_stosm(0x01);
740 /* Loop until driver state indicates finished request */
741 while (sclp_running_state != sclp_running_state_idle) {
742 /* Check for expired request timer */
743 if (get_tod_clock_fast() > timeout && del_timer(timer: &sclp_request_timer))
744 sclp_request_timer.function(&sclp_request_timer);
745 cpu_relax();
746 }
747 local_irq_disable();
748 local_ctl_load(0, &cr0);
749 if (!irq_context)
750 _local_bh_enable();
751 local_tick_enable(old_tick);
752 local_irq_restore(flags);
753
754 /* SYN2: Synchronous wait end (a=runstate, b=sync_count) */
755 sclp_trace(prio: 4, id: "SYN2", a: sclp_running_state, b: sync_count, err: false);
756}
757EXPORT_SYMBOL(sclp_sync_wait);
758
759/* Dispatch changes in send and receive mask to registered listeners. */
760static void
761sclp_dispatch_state_change(void)
762{
763 struct list_head *l;
764 struct sclp_register *reg;
765 unsigned long flags;
766 sccb_mask_t receive_mask;
767 sccb_mask_t send_mask;
768
769 do {
770 spin_lock_irqsave(&sclp_lock, flags);
771 reg = NULL;
772 list_for_each(l, &sclp_reg_list) {
773 reg = list_entry(l, struct sclp_register, list);
774 receive_mask = reg->send_mask & sclp_receive_mask;
775 send_mask = reg->receive_mask & sclp_send_mask;
776 if (reg->sclp_receive_mask != receive_mask ||
777 reg->sclp_send_mask != send_mask) {
778 reg->sclp_receive_mask = receive_mask;
779 reg->sclp_send_mask = send_mask;
780 break;
781 } else
782 reg = NULL;
783 }
784 spin_unlock_irqrestore(lock: &sclp_lock, flags);
785 if (reg && reg->state_change_fn) {
786 /* STCG: State-change callback (b=callback) */
787 sclp_trace(prio: 2, id: "STCG", a: 0, b: (u64)reg->state_change_fn,
788 err: false);
789
790 reg->state_change_fn(reg);
791 }
792 } while (reg);
793}
794
795struct sclp_statechangebuf {
796 struct evbuf_header header;
797 u8 validity_sclp_active_facility_mask : 1;
798 u8 validity_sclp_receive_mask : 1;
799 u8 validity_sclp_send_mask : 1;
800 u8 validity_read_data_function_mask : 1;
801 u16 _zeros : 12;
802 u16 mask_length;
803 u64 sclp_active_facility_mask;
804 u8 masks[2 * 1021 + 4]; /* variable length */
805 /*
806 * u8 sclp_receive_mask[mask_length];
807 * u8 sclp_send_mask[mask_length];
808 * u32 read_data_function_mask;
809 */
810} __attribute__((packed));
811
812
813/* State change event callback. Inform listeners of changes. */
814static void
815sclp_state_change_cb(struct evbuf_header *evbuf)
816{
817 unsigned long flags;
818 struct sclp_statechangebuf *scbuf;
819
820 BUILD_BUG_ON(sizeof(struct sclp_statechangebuf) > PAGE_SIZE);
821
822 scbuf = (struct sclp_statechangebuf *) evbuf;
823 spin_lock_irqsave(&sclp_lock, flags);
824 if (scbuf->validity_sclp_receive_mask)
825 sclp_receive_mask = sccb_get_recv_mask(scbuf);
826 if (scbuf->validity_sclp_send_mask)
827 sclp_send_mask = sccb_get_send_mask(scbuf);
828 spin_unlock_irqrestore(lock: &sclp_lock, flags);
829 if (scbuf->validity_sclp_active_facility_mask)
830 sclp.facilities = scbuf->sclp_active_facility_mask;
831 sclp_dispatch_state_change();
832}
833
834static struct sclp_register sclp_state_change_event = {
835 .receive_mask = EVTYP_STATECHANGE_MASK,
836 .receiver_fn = sclp_state_change_cb
837};
838
839/* Calculate receive and send mask of currently registered listeners.
840 * Called while sclp_lock is locked. */
841static inline void
842__sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
843{
844 struct list_head *l;
845 struct sclp_register *t;
846
847 *receive_mask = 0;
848 *send_mask = 0;
849 list_for_each(l, &sclp_reg_list) {
850 t = list_entry(l, struct sclp_register, list);
851 *receive_mask |= t->receive_mask;
852 *send_mask |= t->send_mask;
853 }
854}
855
856/* Register event listener. Return 0 on success, non-zero otherwise. */
857int
858sclp_register(struct sclp_register *reg)
859{
860 unsigned long flags;
861 sccb_mask_t receive_mask;
862 sccb_mask_t send_mask;
863 int rc;
864
865 /* REG: Event listener registered (b=caller) */
866 sclp_trace_register(prio: 2, id: "REG", a: 0, _RET_IP_, reg);
867
868 rc = sclp_init();
869 if (rc)
870 return rc;
871 spin_lock_irqsave(&sclp_lock, flags);
872 /* Check event mask for collisions */
873 __sclp_get_mask(receive_mask: &receive_mask, send_mask: &send_mask);
874 if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
875 spin_unlock_irqrestore(lock: &sclp_lock, flags);
876 return -EBUSY;
877 }
878 /* Trigger initial state change callback */
879 reg->sclp_receive_mask = 0;
880 reg->sclp_send_mask = 0;
881 list_add(new: &reg->list, head: &sclp_reg_list);
882 spin_unlock_irqrestore(lock: &sclp_lock, flags);
883 rc = sclp_init_mask(calculate: 1);
884 if (rc) {
885 spin_lock_irqsave(&sclp_lock, flags);
886 list_del(entry: &reg->list);
887 spin_unlock_irqrestore(lock: &sclp_lock, flags);
888 }
889 return rc;
890}
891
892EXPORT_SYMBOL(sclp_register);
893
894/* Unregister event listener. */
895void
896sclp_unregister(struct sclp_register *reg)
897{
898 unsigned long flags;
899
900 /* UREG: Event listener unregistered (b=caller) */
901 sclp_trace_register(prio: 2, id: "UREG", a: 0, _RET_IP_, reg);
902
903 spin_lock_irqsave(&sclp_lock, flags);
904 list_del(entry: &reg->list);
905 spin_unlock_irqrestore(lock: &sclp_lock, flags);
906 sclp_init_mask(calculate: 1);
907}
908
909EXPORT_SYMBOL(sclp_unregister);
910
911/* Remove event buffers which are marked processed. Return the number of
912 * remaining event buffers. */
913int
914sclp_remove_processed(struct sccb_header *sccb)
915{
916 struct evbuf_header *evbuf;
917 int unprocessed;
918 u16 remaining;
919
920 evbuf = (struct evbuf_header *) (sccb + 1);
921 unprocessed = 0;
922 remaining = sccb->length - sizeof(struct sccb_header);
923 while (remaining > 0) {
924 remaining -= evbuf->length;
925 if (evbuf->flags & 0x80) {
926 sccb->length -= evbuf->length;
927 memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
928 remaining);
929 } else {
930 unprocessed++;
931 evbuf = (struct evbuf_header *)
932 ((addr_t) evbuf + evbuf->length);
933 }
934 }
935 return unprocessed;
936}
937
938EXPORT_SYMBOL(sclp_remove_processed);
939
940/* Prepare init mask request. Called while sclp_lock is locked. */
941static inline void
942__sclp_make_init_req(sccb_mask_t receive_mask, sccb_mask_t send_mask)
943{
944 struct init_sccb *sccb = sclp_init_sccb;
945
946 clear_page(page: sccb);
947 memset(&sclp_init_req, 0, sizeof(struct sclp_req));
948 sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
949 sclp_init_req.status = SCLP_REQ_FILLED;
950 sclp_init_req.start_count = 0;
951 sclp_init_req.callback = NULL;
952 sclp_init_req.callback_data = NULL;
953 sclp_init_req.sccb = sccb;
954 sccb->header.length = sizeof(*sccb);
955 if (sclp_mask_compat_mode)
956 sccb->mask_length = SCLP_MASK_SIZE_COMPAT;
957 else
958 sccb->mask_length = sizeof(sccb_mask_t);
959 sccb_set_recv_mask(sccb, receive_mask);
960 sccb_set_send_mask(sccb, send_mask);
961 sccb_set_sclp_recv_mask(sccb, 0);
962 sccb_set_sclp_send_mask(sccb, 0);
963}
964
965/* Start init mask request. If calculate is non-zero, calculate the mask as
966 * requested by registered listeners. Use zero mask otherwise. Return 0 on
967 * success, non-zero otherwise. */
968static int
969sclp_init_mask(int calculate)
970{
971 unsigned long flags;
972 struct init_sccb *sccb = sclp_init_sccb;
973 sccb_mask_t receive_mask;
974 sccb_mask_t send_mask;
975 int retry;
976 int rc;
977 unsigned long wait;
978
979 spin_lock_irqsave(&sclp_lock, flags);
980 /* Check if interface is in appropriate state */
981 if (sclp_mask_state != sclp_mask_state_idle) {
982 spin_unlock_irqrestore(lock: &sclp_lock, flags);
983 return -EBUSY;
984 }
985 if (sclp_activation_state == sclp_activation_state_inactive) {
986 spin_unlock_irqrestore(lock: &sclp_lock, flags);
987 return -EINVAL;
988 }
989 sclp_mask_state = sclp_mask_state_initializing;
990 /* Determine mask */
991 if (calculate)
992 __sclp_get_mask(receive_mask: &receive_mask, send_mask: &send_mask);
993 else {
994 receive_mask = 0;
995 send_mask = 0;
996 }
997 rc = -EIO;
998 for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
999 /* Prepare request */
1000 __sclp_make_init_req(receive_mask, send_mask);
1001 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1002 if (sclp_add_request(&sclp_init_req)) {
1003 /* Try again later */
1004 wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
1005 while (time_before(jiffies, wait))
1006 sclp_sync_wait();
1007 spin_lock_irqsave(&sclp_lock, flags);
1008 continue;
1009 }
1010 while (sclp_init_req.status != SCLP_REQ_DONE &&
1011 sclp_init_req.status != SCLP_REQ_FAILED)
1012 sclp_sync_wait();
1013 spin_lock_irqsave(&sclp_lock, flags);
1014 if (sclp_init_req.status == SCLP_REQ_DONE &&
1015 sccb->header.response_code == 0x20) {
1016 /* Successful request */
1017 if (calculate) {
1018 sclp_receive_mask = sccb_get_sclp_recv_mask(sccb);
1019 sclp_send_mask = sccb_get_sclp_send_mask(sccb);
1020 } else {
1021 sclp_receive_mask = 0;
1022 sclp_send_mask = 0;
1023 }
1024 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1025 sclp_dispatch_state_change();
1026 spin_lock_irqsave(&sclp_lock, flags);
1027 rc = 0;
1028 break;
1029 }
1030 }
1031 sclp_mask_state = sclp_mask_state_idle;
1032 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1033 return rc;
1034}
1035
1036/* Deactivate SCLP interface. On success, new requests will be rejected,
1037 * events will no longer be dispatched. Return 0 on success, non-zero
1038 * otherwise. */
1039int
1040sclp_deactivate(void)
1041{
1042 unsigned long flags;
1043 int rc;
1044
1045 spin_lock_irqsave(&sclp_lock, flags);
1046 /* Deactivate can only be called when active */
1047 if (sclp_activation_state != sclp_activation_state_active) {
1048 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1049 return -EINVAL;
1050 }
1051 sclp_activation_state = sclp_activation_state_deactivating;
1052 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1053 rc = sclp_init_mask(calculate: 0);
1054 spin_lock_irqsave(&sclp_lock, flags);
1055 if (rc == 0)
1056 sclp_activation_state = sclp_activation_state_inactive;
1057 else
1058 sclp_activation_state = sclp_activation_state_active;
1059 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1060 return rc;
1061}
1062
1063EXPORT_SYMBOL(sclp_deactivate);
1064
1065/* Reactivate SCLP interface after sclp_deactivate. On success, new
1066 * requests will be accepted, events will be dispatched again. Return 0 on
1067 * success, non-zero otherwise. */
1068int
1069sclp_reactivate(void)
1070{
1071 unsigned long flags;
1072 int rc;
1073
1074 spin_lock_irqsave(&sclp_lock, flags);
1075 /* Reactivate can only be called when inactive */
1076 if (sclp_activation_state != sclp_activation_state_inactive) {
1077 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1078 return -EINVAL;
1079 }
1080 sclp_activation_state = sclp_activation_state_activating;
1081 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1082 rc = sclp_init_mask(calculate: 1);
1083 spin_lock_irqsave(&sclp_lock, flags);
1084 if (rc == 0)
1085 sclp_activation_state = sclp_activation_state_active;
1086 else
1087 sclp_activation_state = sclp_activation_state_inactive;
1088 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1089 return rc;
1090}
1091
1092EXPORT_SYMBOL(sclp_reactivate);
1093
1094/* Handler for external interruption used during initialization. Modify
1095 * request state to done. */
1096static void sclp_check_handler(struct ext_code ext_code,
1097 unsigned int param32, unsigned long param64)
1098{
1099 u32 finished_sccb;
1100
1101 inc_irq_stat(IRQEXT_SCP);
1102 finished_sccb = param32 & 0xfffffff8;
1103 /* Is this the interrupt we are waiting for? */
1104 if (finished_sccb == 0)
1105 return;
1106 if (finished_sccb != __pa(sclp_init_sccb))
1107 panic(fmt: "sclp: unsolicited interrupt for buffer at 0x%x\n",
1108 finished_sccb);
1109 spin_lock(lock: &sclp_lock);
1110 if (sclp_running_state == sclp_running_state_running) {
1111 sclp_init_req.status = SCLP_REQ_DONE;
1112 sclp_running_state = sclp_running_state_idle;
1113 }
1114 spin_unlock(lock: &sclp_lock);
1115}
1116
1117/* Initial init mask request timed out. Modify request state to failed. */
1118static void
1119sclp_check_timeout(struct timer_list *unused)
1120{
1121 unsigned long flags;
1122
1123 spin_lock_irqsave(&sclp_lock, flags);
1124 if (sclp_running_state == sclp_running_state_running) {
1125 sclp_init_req.status = SCLP_REQ_FAILED;
1126 sclp_running_state = sclp_running_state_idle;
1127 }
1128 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1129}
1130
1131/* Perform a check of the SCLP interface. Return zero if the interface is
1132 * available and there are no pending requests from a previous instance.
1133 * Return non-zero otherwise. */
1134static int
1135sclp_check_interface(void)
1136{
1137 struct init_sccb *sccb;
1138 unsigned long flags;
1139 int retry;
1140 int rc;
1141
1142 spin_lock_irqsave(&sclp_lock, flags);
1143 /* Prepare init mask command */
1144 rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
1145 if (rc) {
1146 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1147 return rc;
1148 }
1149 for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
1150 __sclp_make_init_req(receive_mask: 0, send_mask: 0);
1151 sccb = (struct init_sccb *) sclp_init_req.sccb;
1152 rc = sclp_service_call_trace(command: sclp_init_req.command, sccb);
1153 if (rc == -EIO)
1154 break;
1155 sclp_init_req.status = SCLP_REQ_RUNNING;
1156 sclp_running_state = sclp_running_state_running;
1157 __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
1158 cb: sclp_check_timeout);
1159 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1160 /* Enable service-signal interruption - needs to happen
1161 * with IRQs enabled. */
1162 irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1163 /* Wait for signal from interrupt or timeout */
1164 sclp_sync_wait();
1165 /* Disable service-signal interruption - needs to happen
1166 * with IRQs enabled. */
1167 irq_subclass_unregister(IRQ_SUBCLASS_SERVICE_SIGNAL);
1168 spin_lock_irqsave(&sclp_lock, flags);
1169 del_timer(timer: &sclp_request_timer);
1170 rc = -EBUSY;
1171 if (sclp_init_req.status == SCLP_REQ_DONE) {
1172 if (sccb->header.response_code == 0x20) {
1173 rc = 0;
1174 break;
1175 } else if (sccb->header.response_code == 0x74f0) {
1176 if (!sclp_mask_compat_mode) {
1177 sclp_mask_compat_mode = true;
1178 retry = 0;
1179 }
1180 }
1181 }
1182 }
1183 unregister_external_irq(EXT_IRQ_SERVICE_SIG, sclp_check_handler);
1184 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1185 return rc;
1186}
1187
1188/* Reboot event handler. Reset send and receive mask to prevent pending SCLP
1189 * events from interfering with rebooted system. */
1190static int
1191sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
1192{
1193 sclp_deactivate();
1194 return NOTIFY_DONE;
1195}
1196
1197static struct notifier_block sclp_reboot_notifier = {
1198 .notifier_call = sclp_reboot_event
1199};
1200
1201static ssize_t con_pages_show(struct device_driver *dev, char *buf)
1202{
1203 return sysfs_emit(buf, fmt: "%i\n", sclp_console_pages);
1204}
1205
1206static DRIVER_ATTR_RO(con_pages);
1207
1208static ssize_t con_drop_store(struct device_driver *dev, const char *buf, size_t count)
1209{
1210 int rc;
1211
1212 rc = kstrtobool(s: buf, res: &sclp_console_drop);
1213 return rc ?: count;
1214}
1215
1216static ssize_t con_drop_show(struct device_driver *dev, char *buf)
1217{
1218 return sysfs_emit(buf, fmt: "%i\n", sclp_console_drop);
1219}
1220
1221static DRIVER_ATTR_RW(con_drop);
1222
1223static ssize_t con_full_show(struct device_driver *dev, char *buf)
1224{
1225 return sysfs_emit(buf, fmt: "%lu\n", sclp_console_full);
1226}
1227
1228static DRIVER_ATTR_RO(con_full);
1229
1230static struct attribute *sclp_drv_attrs[] = {
1231 &driver_attr_con_pages.attr,
1232 &driver_attr_con_drop.attr,
1233 &driver_attr_con_full.attr,
1234 NULL,
1235};
1236static struct attribute_group sclp_drv_attr_group = {
1237 .attrs = sclp_drv_attrs,
1238};
1239static const struct attribute_group *sclp_drv_attr_groups[] = {
1240 &sclp_drv_attr_group,
1241 NULL,
1242};
1243
1244static struct platform_driver sclp_pdrv = {
1245 .driver = {
1246 .name = "sclp",
1247 .groups = sclp_drv_attr_groups,
1248 },
1249};
1250
1251/* Initialize SCLP driver. Return zero if driver is operational, non-zero
1252 * otherwise. */
1253static int
1254sclp_init(void)
1255{
1256 unsigned long flags;
1257 int rc = 0;
1258
1259 spin_lock_irqsave(&sclp_lock, flags);
1260 /* Check for previous or running initialization */
1261 if (sclp_init_state != sclp_init_state_uninitialized)
1262 goto fail_unlock;
1263 sclp_init_state = sclp_init_state_initializing;
1264 sclp_read_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
1265 sclp_init_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
1266 BUG_ON(!sclp_read_sccb || !sclp_init_sccb);
1267 /* Set up variables */
1268 list_add(new: &sclp_state_change_event.list, head: &sclp_reg_list);
1269 timer_setup(&sclp_request_timer, NULL, 0);
1270 timer_setup(&sclp_queue_timer, sclp_req_queue_timeout, 0);
1271 /* Check interface */
1272 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1273 rc = sclp_check_interface();
1274 spin_lock_irqsave(&sclp_lock, flags);
1275 if (rc)
1276 goto fail_init_state_uninitialized;
1277 /* Register reboot handler */
1278 rc = register_reboot_notifier(&sclp_reboot_notifier);
1279 if (rc)
1280 goto fail_init_state_uninitialized;
1281 /* Register interrupt handler */
1282 rc = register_external_irq(EXT_IRQ_SERVICE_SIG, sclp_interrupt_handler);
1283 if (rc)
1284 goto fail_unregister_reboot_notifier;
1285 sclp_init_state = sclp_init_state_initialized;
1286 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1287 /* Enable service-signal external interruption - needs to happen with
1288 * IRQs enabled. */
1289 irq_subclass_register(IRQ_SUBCLASS_SERVICE_SIGNAL);
1290 sclp_init_mask(calculate: 1);
1291 return 0;
1292
1293fail_unregister_reboot_notifier:
1294 unregister_reboot_notifier(&sclp_reboot_notifier);
1295fail_init_state_uninitialized:
1296 sclp_init_state = sclp_init_state_uninitialized;
1297 free_page((unsigned long) sclp_read_sccb);
1298 free_page((unsigned long) sclp_init_sccb);
1299fail_unlock:
1300 spin_unlock_irqrestore(lock: &sclp_lock, flags);
1301 return rc;
1302}
1303
1304static __init int sclp_initcall(void)
1305{
1306 int rc;
1307
1308 rc = platform_driver_register(&sclp_pdrv);
1309 if (rc)
1310 return rc;
1311
1312 return sclp_init();
1313}
1314
1315arch_initcall(sclp_initcall);
1316

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