xref: /openbmc/linux/drivers/crypto/ccp/ccp-dev.c (revision cf9441ad) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * AMD Cryptographic Coprocessor (CCP) driver
4  *
5  * Copyright (C) 2013,2017 Advanced Micro Devices, Inc.
6  *
7  * Author: Tom Lendacky <thomas.lendacky@amd.com>
8  * Author: Gary R Hook <gary.hook@amd.com>
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/kthread.h>
13 #include <linux/sched.h>
14 #include <linux/interrupt.h>
15 #include <linux/spinlock.h>
16 #include <linux/spinlock_types.h>
17 #include <linux/types.h>
18 #include <linux/mutex.h>
19 #include <linux/delay.h>
20 #include <linux/hw_random.h>
21 #include <linux/cpu.h>
22 #ifdef CONFIG_X86
23 #include <asm/cpu_device_id.h>
24 #endif
25 #include <linux/ccp.h>
26 
27 #include "ccp-dev.h"
28 
29 struct ccp_tasklet_data {
30 	struct completion completion;
31 	struct ccp_cmd *cmd;
32 };
33 
34 /* Human-readable error strings */
35 #define CCP_MAX_ERROR_CODE	64
36 static char *ccp_error_codes[] = {
37 	"",
38 	"ILLEGAL_ENGINE",
39 	"ILLEGAL_KEY_ID",
40 	"ILLEGAL_FUNCTION_TYPE",
41 	"ILLEGAL_FUNCTION_MODE",
42 	"ILLEGAL_FUNCTION_ENCRYPT",
43 	"ILLEGAL_FUNCTION_SIZE",
44 	"Zlib_MISSING_INIT_EOM",
45 	"ILLEGAL_FUNCTION_RSVD",
46 	"ILLEGAL_BUFFER_LENGTH",
47 	"VLSB_FAULT",
48 	"ILLEGAL_MEM_ADDR",
49 	"ILLEGAL_MEM_SEL",
50 	"ILLEGAL_CONTEXT_ID",
51 	"ILLEGAL_KEY_ADDR",
52 	"0xF Reserved",
53 	"Zlib_ILLEGAL_MULTI_QUEUE",
54 	"Zlib_ILLEGAL_JOBID_CHANGE",
55 	"CMD_TIMEOUT",
56 	"IDMA0_AXI_SLVERR",
57 	"IDMA0_AXI_DECERR",
58 	"0x15 Reserved",
59 	"IDMA1_AXI_SLAVE_FAULT",
60 	"IDMA1_AIXI_DECERR",
61 	"0x18 Reserved",
62 	"ZLIBVHB_AXI_SLVERR",
63 	"ZLIBVHB_AXI_DECERR",
64 	"0x1B Reserved",
65 	"ZLIB_UNEXPECTED_EOM",
66 	"ZLIB_EXTRA_DATA",
67 	"ZLIB_BTYPE",
68 	"ZLIB_UNDEFINED_SYMBOL",
69 	"ZLIB_UNDEFINED_DISTANCE_S",
70 	"ZLIB_CODE_LENGTH_SYMBOL",
71 	"ZLIB _VHB_ILLEGAL_FETCH",
72 	"ZLIB_UNCOMPRESSED_LEN",
73 	"ZLIB_LIMIT_REACHED",
74 	"ZLIB_CHECKSUM_MISMATCH0",
75 	"ODMA0_AXI_SLVERR",
76 	"ODMA0_AXI_DECERR",
77 	"0x28 Reserved",
78 	"ODMA1_AXI_SLVERR",
79 	"ODMA1_AXI_DECERR",
80 };
81 
82 void ccp_log_error(struct ccp_device *d, unsigned int e)
83 {
84 	if (WARN_ON(e >= CCP_MAX_ERROR_CODE))
85 		return;
86 
87 	if (e < ARRAY_SIZE(ccp_error_codes))
88 		dev_err(d->dev, "CCP error %d: %s\n", e, ccp_error_codes[e]);
89 	else
90 		dev_err(d->dev, "CCP error %d: Unknown Error\n", e);
91 }
92 
93 /* List of CCPs, CCP count, read-write access lock, and access functions
94  *
95  * Lock structure: get ccp_unit_lock for reading whenever we need to
96  * examine the CCP list. While holding it for reading we can acquire
97  * the RR lock to update the round-robin next-CCP pointer. The unit lock
98  * must be acquired before the RR lock.
99  *
100  * If the unit-lock is acquired for writing, we have total control over
101  * the list, so there's no value in getting the RR lock.
102  */
103 static DEFINE_RWLOCK(ccp_unit_lock);
104 static LIST_HEAD(ccp_units);
105 
106 /* Round-robin counter */
107 static DEFINE_SPINLOCK(ccp_rr_lock);
108 static struct ccp_device *ccp_rr;
109 
110 /**
111  * ccp_add_device - add a CCP device to the list
112  *
113  * @ccp: ccp_device struct pointer
114  *
115  * Put this CCP on the unit list, which makes it available
116  * for use.
117  *
118  * Returns zero if a CCP device is present, -ENODEV otherwise.
119  */
120 void ccp_add_device(struct ccp_device *ccp)
121 {
122 	unsigned long flags;
123 
124 	write_lock_irqsave(&ccp_unit_lock, flags);
125 	list_add_tail(&ccp->entry, &ccp_units);
126 	if (!ccp_rr)
127 		/* We already have the list lock (we're first) so this
128 		 * pointer can't change on us. Set its initial value.
129 		 */
130 		ccp_rr = ccp;
131 	write_unlock_irqrestore(&ccp_unit_lock, flags);
132 }
133 
134 /**
135  * ccp_del_device - remove a CCP device from the list
136  *
137  * @ccp: ccp_device struct pointer
138  *
139  * Remove this unit from the list of devices. If the next device
140  * up for use is this one, adjust the pointer. If this is the last
141  * device, NULL the pointer.
142  */
143 void ccp_del_device(struct ccp_device *ccp)
144 {
145 	unsigned long flags;
146 
147 	write_lock_irqsave(&ccp_unit_lock, flags);
148 	if (ccp_rr == ccp) {
149 		/* ccp_unit_lock is read/write; any read access
150 		 * will be suspended while we make changes to the
151 		 * list and RR pointer.
152 		 */
153 		if (list_is_last(&ccp_rr->entry, &ccp_units))
154 			ccp_rr = list_first_entry(&ccp_units, struct ccp_device,
155 						  entry);
156 		else
157 			ccp_rr = list_next_entry(ccp_rr, entry);
158 	}
159 	list_del(&ccp->entry);
160 	if (list_empty(&ccp_units))
161 		ccp_rr = NULL;
162 	write_unlock_irqrestore(&ccp_unit_lock, flags);
163 }
164 
165 
166 
167 int ccp_register_rng(struct ccp_device *ccp)
168 {
169 	int ret = 0;
170 
171 	dev_dbg(ccp->dev, "Registering RNG...\n");
172 	/* Register an RNG */
173 	ccp->hwrng.name = ccp->rngname;
174 	ccp->hwrng.read = ccp_trng_read;
175 	ret = hwrng_register(&ccp->hwrng);
176 	if (ret)
177 		dev_err(ccp->dev, "error registering hwrng (%d)\n", ret);
178 
179 	return ret;
180 }
181 
182 void ccp_unregister_rng(struct ccp_device *ccp)
183 {
184 	if (ccp->hwrng.name)
185 		hwrng_unregister(&ccp->hwrng);
186 }
187 
188 static struct ccp_device *ccp_get_device(void)
189 {
190 	unsigned long flags;
191 	struct ccp_device *dp = NULL;
192 
193 	/* We round-robin through the unit list.
194 	 * The (ccp_rr) pointer refers to the next unit to use.
195 	 */
196 	read_lock_irqsave(&ccp_unit_lock, flags);
197 	if (!list_empty(&ccp_units)) {
198 		spin_lock(&ccp_rr_lock);
199 		dp = ccp_rr;
200 		if (list_is_last(&ccp_rr->entry, &ccp_units))
201 			ccp_rr = list_first_entry(&ccp_units, struct ccp_device,
202 						  entry);
203 		else
204 			ccp_rr = list_next_entry(ccp_rr, entry);
205 		spin_unlock(&ccp_rr_lock);
206 	}
207 	read_unlock_irqrestore(&ccp_unit_lock, flags);
208 
209 	return dp;
210 }
211 
212 /**
213  * ccp_present - check if a CCP device is present
214  *
215  * Returns zero if a CCP device is present, -ENODEV otherwise.
216  */
217 int ccp_present(void)
218 {
219 	unsigned long flags;
220 	int ret;
221 
222 	read_lock_irqsave(&ccp_unit_lock, flags);
223 	ret = list_empty(&ccp_units);
224 	read_unlock_irqrestore(&ccp_unit_lock, flags);
225 
226 	return ret ? -ENODEV : 0;
227 }
228 EXPORT_SYMBOL_GPL(ccp_present);
229 
230 /**
231  * ccp_version - get the version of the CCP device
232  *
233  * Returns the version from the first unit on the list;
234  * otherwise a zero if no CCP device is present
235  */
236 unsigned int ccp_version(void)
237 {
238 	struct ccp_device *dp;
239 	unsigned long flags;
240 	int ret = 0;
241 
242 	read_lock_irqsave(&ccp_unit_lock, flags);
243 	if (!list_empty(&ccp_units)) {
244 		dp = list_first_entry(&ccp_units, struct ccp_device, entry);
245 		ret = dp->vdata->version;
246 	}
247 	read_unlock_irqrestore(&ccp_unit_lock, flags);
248 
249 	return ret;
250 }
251 EXPORT_SYMBOL_GPL(ccp_version);
252 
253 /**
254  * ccp_enqueue_cmd - queue an operation for processing by the CCP
255  *
256  * @cmd: ccp_cmd struct to be processed
257  *
258  * Queue a cmd to be processed by the CCP. If queueing the cmd
259  * would exceed the defined length of the cmd queue the cmd will
260  * only be queued if the CCP_CMD_MAY_BACKLOG flag is set and will
261  * result in a return code of -EBUSY.
262  *
263  * The callback routine specified in the ccp_cmd struct will be
264  * called to notify the caller of completion (if the cmd was not
265  * backlogged) or advancement out of the backlog. If the cmd has
266  * advanced out of the backlog the "err" value of the callback
267  * will be -EINPROGRESS. Any other "err" value during callback is
268  * the result of the operation.
269  *
270  * The cmd has been successfully queued if:
271  *   the return code is -EINPROGRESS or
272  *   the return code is -EBUSY and CCP_CMD_MAY_BACKLOG flag is set
273  */
274 int ccp_enqueue_cmd(struct ccp_cmd *cmd)
275 {
276 	struct ccp_device *ccp;
277 	unsigned long flags;
278 	unsigned int i;
279 	int ret;
280 
281 	/* Some commands might need to be sent to a specific device */
282 	ccp = cmd->ccp ? cmd->ccp : ccp_get_device();
283 
284 	if (!ccp)
285 		return -ENODEV;
286 
287 	/* Caller must supply a callback routine */
288 	if (!cmd->callback)
289 		return -EINVAL;
290 
291 	cmd->ccp = ccp;
292 
293 	spin_lock_irqsave(&ccp->cmd_lock, flags);
294 
295 	i = ccp->cmd_q_count;
296 
297 	if (ccp->cmd_count >= MAX_CMD_QLEN) {
298 		if (cmd->flags & CCP_CMD_MAY_BACKLOG) {
299 			ret = -EBUSY;
300 			list_add_tail(&cmd->entry, &ccp->backlog);
301 		} else {
302 			ret = -ENOSPC;
303 		}
304 	} else {
305 		ret = -EINPROGRESS;
306 		ccp->cmd_count++;
307 		list_add_tail(&cmd->entry, &ccp->cmd);
308 
309 		/* Find an idle queue */
310 		if (!ccp->suspending) {
311 			for (i = 0; i < ccp->cmd_q_count; i++) {
312 				if (ccp->cmd_q[i].active)
313 					continue;
314 
315 				break;
316 			}
317 		}
318 	}
319 
320 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
321 
322 	/* If we found an idle queue, wake it up */
323 	if (i < ccp->cmd_q_count)
324 		wake_up_process(ccp->cmd_q[i].kthread);
325 
326 	return ret;
327 }
328 EXPORT_SYMBOL_GPL(ccp_enqueue_cmd);
329 
330 static void ccp_do_cmd_backlog(struct work_struct *work)
331 {
332 	struct ccp_cmd *cmd = container_of(work, struct ccp_cmd, work);
333 	struct ccp_device *ccp = cmd->ccp;
334 	unsigned long flags;
335 	unsigned int i;
336 
337 	cmd->callback(cmd->data, -EINPROGRESS);
338 
339 	spin_lock_irqsave(&ccp->cmd_lock, flags);
340 
341 	ccp->cmd_count++;
342 	list_add_tail(&cmd->entry, &ccp->cmd);
343 
344 	/* Find an idle queue */
345 	for (i = 0; i < ccp->cmd_q_count; i++) {
346 		if (ccp->cmd_q[i].active)
347 			continue;
348 
349 		break;
350 	}
351 
352 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
353 
354 	/* If we found an idle queue, wake it up */
355 	if (i < ccp->cmd_q_count)
356 		wake_up_process(ccp->cmd_q[i].kthread);
357 }
358 
359 static struct ccp_cmd *ccp_dequeue_cmd(struct ccp_cmd_queue *cmd_q)
360 {
361 	struct ccp_device *ccp = cmd_q->ccp;
362 	struct ccp_cmd *cmd = NULL;
363 	struct ccp_cmd *backlog = NULL;
364 	unsigned long flags;
365 
366 	spin_lock_irqsave(&ccp->cmd_lock, flags);
367 
368 	cmd_q->active = 0;
369 
370 	if (ccp->suspending) {
371 		cmd_q->suspended = 1;
372 
373 		spin_unlock_irqrestore(&ccp->cmd_lock, flags);
374 		wake_up_interruptible(&ccp->suspend_queue);
375 
376 		return NULL;
377 	}
378 
379 	if (ccp->cmd_count) {
380 		cmd_q->active = 1;
381 
382 		cmd = list_first_entry(&ccp->cmd, struct ccp_cmd, entry);
383 		list_del(&cmd->entry);
384 
385 		ccp->cmd_count--;
386 	}
387 
388 	if (!list_empty(&ccp->backlog)) {
389 		backlog = list_first_entry(&ccp->backlog, struct ccp_cmd,
390 					   entry);
391 		list_del(&backlog->entry);
392 	}
393 
394 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
395 
396 	if (backlog) {
397 		INIT_WORK(&backlog->work, ccp_do_cmd_backlog);
398 		schedule_work(&backlog->work);
399 	}
400 
401 	return cmd;
402 }
403 
404 static void ccp_do_cmd_complete(unsigned long data)
405 {
406 	struct ccp_tasklet_data *tdata = (struct ccp_tasklet_data *)data;
407 	struct ccp_cmd *cmd = tdata->cmd;
408 
409 	cmd->callback(cmd->data, cmd->ret);
410 
411 	complete(&tdata->completion);
412 }
413 
414 /**
415  * ccp_cmd_queue_thread - create a kernel thread to manage a CCP queue
416  *
417  * @data: thread-specific data
418  */
419 int ccp_cmd_queue_thread(void *data)
420 {
421 	struct ccp_cmd_queue *cmd_q = (struct ccp_cmd_queue *)data;
422 	struct ccp_cmd *cmd;
423 	struct ccp_tasklet_data tdata;
424 	struct tasklet_struct tasklet;
425 
426 	tasklet_init(&tasklet, ccp_do_cmd_complete, (unsigned long)&tdata);
427 
428 	set_current_state(TASK_INTERRUPTIBLE);
429 	while (!kthread_should_stop()) {
430 		schedule();
431 
432 		set_current_state(TASK_INTERRUPTIBLE);
433 
434 		cmd = ccp_dequeue_cmd(cmd_q);
435 		if (!cmd)
436 			continue;
437 
438 		__set_current_state(TASK_RUNNING);
439 
440 		/* Execute the command */
441 		cmd->ret = ccp_run_cmd(cmd_q, cmd);
442 
443 		/* Schedule the completion callback */
444 		tdata.cmd = cmd;
445 		init_completion(&tdata.completion);
446 		tasklet_schedule(&tasklet);
447 		wait_for_completion(&tdata.completion);
448 	}
449 
450 	__set_current_state(TASK_RUNNING);
451 
452 	return 0;
453 }
454 
455 /**
456  * ccp_alloc_struct - allocate and initialize the ccp_device struct
457  *
458  * @dev: device struct of the CCP
459  */
460 struct ccp_device *ccp_alloc_struct(struct sp_device *sp)
461 {
462 	struct device *dev = sp->dev;
463 	struct ccp_device *ccp;
464 
465 	ccp = devm_kzalloc(dev, sizeof(*ccp), GFP_KERNEL);
466 	if (!ccp)
467 		return NULL;
468 	ccp->dev = dev;
469 	ccp->sp = sp;
470 	ccp->axcache = sp->axcache;
471 
472 	INIT_LIST_HEAD(&ccp->cmd);
473 	INIT_LIST_HEAD(&ccp->backlog);
474 
475 	spin_lock_init(&ccp->cmd_lock);
476 	mutex_init(&ccp->req_mutex);
477 	mutex_init(&ccp->sb_mutex);
478 	ccp->sb_count = KSB_COUNT;
479 	ccp->sb_start = 0;
480 
481 	/* Initialize the wait queues */
482 	init_waitqueue_head(&ccp->sb_queue);
483 	init_waitqueue_head(&ccp->suspend_queue);
484 
485 	snprintf(ccp->name, MAX_CCP_NAME_LEN, "ccp-%u", sp->ord);
486 	snprintf(ccp->rngname, MAX_CCP_NAME_LEN, "ccp-%u-rng", sp->ord);
487 
488 	return ccp;
489 }
490 
491 int ccp_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
492 {
493 	struct ccp_device *ccp = container_of(rng, struct ccp_device, hwrng);
494 	u32 trng_value;
495 	int len = min_t(int, sizeof(trng_value), max);
496 
497 	/* Locking is provided by the caller so we can update device
498 	 * hwrng-related fields safely
499 	 */
500 	trng_value = ioread32(ccp->io_regs + TRNG_OUT_REG);
501 	if (!trng_value) {
502 		/* Zero is returned if not data is available or if a
503 		 * bad-entropy error is present. Assume an error if
504 		 * we exceed TRNG_RETRIES reads of zero.
505 		 */
506 		if (ccp->hwrng_retries++ > TRNG_RETRIES)
507 			return -EIO;
508 
509 		return 0;
510 	}
511 
512 	/* Reset the counter and save the rng value */
513 	ccp->hwrng_retries = 0;
514 	memcpy(data, &trng_value, len);
515 
516 	return len;
517 }
518 
519 #ifdef CONFIG_PM
520 bool ccp_queues_suspended(struct ccp_device *ccp)
521 {
522 	unsigned int suspended = 0;
523 	unsigned long flags;
524 	unsigned int i;
525 
526 	spin_lock_irqsave(&ccp->cmd_lock, flags);
527 
528 	for (i = 0; i < ccp->cmd_q_count; i++)
529 		if (ccp->cmd_q[i].suspended)
530 			suspended++;
531 
532 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
533 
534 	return ccp->cmd_q_count == suspended;
535 }
536 
537 int ccp_dev_suspend(struct sp_device *sp, pm_message_t state)
538 {
539 	struct ccp_device *ccp = sp->ccp_data;
540 	unsigned long flags;
541 	unsigned int i;
542 
543 	spin_lock_irqsave(&ccp->cmd_lock, flags);
544 
545 	ccp->suspending = 1;
546 
547 	/* Wake all the queue kthreads to prepare for suspend */
548 	for (i = 0; i < ccp->cmd_q_count; i++)
549 		wake_up_process(ccp->cmd_q[i].kthread);
550 
551 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
552 
553 	/* Wait for all queue kthreads to say they're done */
554 	while (!ccp_queues_suspended(ccp))
555 		wait_event_interruptible(ccp->suspend_queue,
556 					 ccp_queues_suspended(ccp));
557 
558 	return 0;
559 }
560 
561 int ccp_dev_resume(struct sp_device *sp)
562 {
563 	struct ccp_device *ccp = sp->ccp_data;
564 	unsigned long flags;
565 	unsigned int i;
566 
567 	spin_lock_irqsave(&ccp->cmd_lock, flags);
568 
569 	ccp->suspending = 0;
570 
571 	/* Wake up all the kthreads */
572 	for (i = 0; i < ccp->cmd_q_count; i++) {
573 		ccp->cmd_q[i].suspended = 0;
574 		wake_up_process(ccp->cmd_q[i].kthread);
575 	}
576 
577 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
578 
579 	return 0;
580 }
581 #endif
582 
583 int ccp_dev_init(struct sp_device *sp)
584 {
585 	struct device *dev = sp->dev;
586 	struct ccp_device *ccp;
587 	int ret;
588 
589 	ret = -ENOMEM;
590 	ccp = ccp_alloc_struct(sp);
591 	if (!ccp)
592 		goto e_err;
593 	sp->ccp_data = ccp;
594 
595 	ccp->vdata = (struct ccp_vdata *)sp->dev_vdata->ccp_vdata;
596 	if (!ccp->vdata || !ccp->vdata->version) {
597 		ret = -ENODEV;
598 		dev_err(dev, "missing driver data\n");
599 		goto e_err;
600 	}
601 
602 	ccp->use_tasklet = sp->use_tasklet;
603 
604 	ccp->io_regs = sp->io_map + ccp->vdata->offset;
605 	if (ccp->vdata->setup)
606 		ccp->vdata->setup(ccp);
607 
608 	ret = ccp->vdata->perform->init(ccp);
609 	if (ret)
610 		goto e_err;
611 
612 	dev_notice(dev, "ccp enabled\n");
613 
614 	return 0;
615 
616 e_err:
617 	sp->ccp_data = NULL;
618 
619 	dev_notice(dev, "ccp initialization failed\n");
620 
621 	return ret;
622 }
623 
624 void ccp_dev_destroy(struct sp_device *sp)
625 {
626 	struct ccp_device *ccp = sp->ccp_data;
627 
628 	if (!ccp)
629 		return;
630 
631 	ccp->vdata->perform->destroy(ccp);
632 }
633