xref: /openbmc/linux/drivers/crypto/ccp/ccp-dev.c (revision 23966841) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * AMD Cryptographic Coprocessor (CCP) driver
4  *
5  * Copyright (C) 2013,2019 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/module.h>
12 #include <linux/kernel.h>
13 #include <linux/kthread.h>
14 #include <linux/sched.h>
15 #include <linux/interrupt.h>
16 #include <linux/spinlock.h>
17 #include <linux/spinlock_types.h>
18 #include <linux/types.h>
19 #include <linux/mutex.h>
20 #include <linux/delay.h>
21 #include <linux/hw_random.h>
22 #include <linux/cpu.h>
23 #include <linux/atomic.h>
24 #ifdef CONFIG_X86
25 #include <asm/cpu_device_id.h>
26 #endif
27 #include <linux/ccp.h>
28 
29 #include "ccp-dev.h"
30 
31 #define MAX_CCPS 32
32 
33 /* Limit CCP use to a specifed number of queues per device */
34 static unsigned int nqueues = 0;
35 module_param(nqueues, uint, 0444);
36 MODULE_PARM_DESC(nqueues, "Number of queues per CCP (minimum 1; default: all available)");
37 
38 /* Limit the maximum number of configured CCPs */
39 static atomic_t dev_count = ATOMIC_INIT(0);
40 static unsigned int max_devs = MAX_CCPS;
41 module_param(max_devs, uint, 0444);
42 MODULE_PARM_DESC(max_devs, "Maximum number of CCPs to enable (default: all; 0 disables all CCPs)");
43 
44 struct ccp_tasklet_data {
45 	struct completion completion;
46 	struct ccp_cmd *cmd;
47 };
48 
49 /* Human-readable error strings */
50 #define CCP_MAX_ERROR_CODE	64
51 static char *ccp_error_codes[] = {
52 	"",
53 	"ILLEGAL_ENGINE",
54 	"ILLEGAL_KEY_ID",
55 	"ILLEGAL_FUNCTION_TYPE",
56 	"ILLEGAL_FUNCTION_MODE",
57 	"ILLEGAL_FUNCTION_ENCRYPT",
58 	"ILLEGAL_FUNCTION_SIZE",
59 	"Zlib_MISSING_INIT_EOM",
60 	"ILLEGAL_FUNCTION_RSVD",
61 	"ILLEGAL_BUFFER_LENGTH",
62 	"VLSB_FAULT",
63 	"ILLEGAL_MEM_ADDR",
64 	"ILLEGAL_MEM_SEL",
65 	"ILLEGAL_CONTEXT_ID",
66 	"ILLEGAL_KEY_ADDR",
67 	"0xF Reserved",
68 	"Zlib_ILLEGAL_MULTI_QUEUE",
69 	"Zlib_ILLEGAL_JOBID_CHANGE",
70 	"CMD_TIMEOUT",
71 	"IDMA0_AXI_SLVERR",
72 	"IDMA0_AXI_DECERR",
73 	"0x15 Reserved",
74 	"IDMA1_AXI_SLAVE_FAULT",
75 	"IDMA1_AIXI_DECERR",
76 	"0x18 Reserved",
77 	"ZLIBVHB_AXI_SLVERR",
78 	"ZLIBVHB_AXI_DECERR",
79 	"0x1B Reserved",
80 	"ZLIB_UNEXPECTED_EOM",
81 	"ZLIB_EXTRA_DATA",
82 	"ZLIB_BTYPE",
83 	"ZLIB_UNDEFINED_SYMBOL",
84 	"ZLIB_UNDEFINED_DISTANCE_S",
85 	"ZLIB_CODE_LENGTH_SYMBOL",
86 	"ZLIB _VHB_ILLEGAL_FETCH",
87 	"ZLIB_UNCOMPRESSED_LEN",
88 	"ZLIB_LIMIT_REACHED",
89 	"ZLIB_CHECKSUM_MISMATCH0",
90 	"ODMA0_AXI_SLVERR",
91 	"ODMA0_AXI_DECERR",
92 	"0x28 Reserved",
93 	"ODMA1_AXI_SLVERR",
94 	"ODMA1_AXI_DECERR",
95 };
96 
97 void ccp_log_error(struct ccp_device *d, unsigned int e)
98 {
99 	if (WARN_ON(e >= CCP_MAX_ERROR_CODE))
100 		return;
101 
102 	if (e < ARRAY_SIZE(ccp_error_codes))
103 		dev_err(d->dev, "CCP error %d: %s\n", e, ccp_error_codes[e]);
104 	else
105 		dev_err(d->dev, "CCP error %d: Unknown Error\n", e);
106 }
107 
108 /* List of CCPs, CCP count, read-write access lock, and access functions
109  *
110  * Lock structure: get ccp_unit_lock for reading whenever we need to
111  * examine the CCP list. While holding it for reading we can acquire
112  * the RR lock to update the round-robin next-CCP pointer. The unit lock
113  * must be acquired before the RR lock.
114  *
115  * If the unit-lock is acquired for writing, we have total control over
116  * the list, so there's no value in getting the RR lock.
117  */
118 static DEFINE_RWLOCK(ccp_unit_lock);
119 static LIST_HEAD(ccp_units);
120 
121 /* Round-robin counter */
122 static DEFINE_SPINLOCK(ccp_rr_lock);
123 static struct ccp_device *ccp_rr;
124 
125 /**
126  * ccp_add_device - add a CCP device to the list
127  *
128  * @ccp: ccp_device struct pointer
129  *
130  * Put this CCP on the unit list, which makes it available
131  * for use.
132  *
133  * Returns zero if a CCP device is present, -ENODEV otherwise.
134  */
135 void ccp_add_device(struct ccp_device *ccp)
136 {
137 	unsigned long flags;
138 
139 	write_lock_irqsave(&ccp_unit_lock, flags);
140 	list_add_tail(&ccp->entry, &ccp_units);
141 	if (!ccp_rr)
142 		/* We already have the list lock (we're first) so this
143 		 * pointer can't change on us. Set its initial value.
144 		 */
145 		ccp_rr = ccp;
146 	write_unlock_irqrestore(&ccp_unit_lock, flags);
147 }
148 
149 /**
150  * ccp_del_device - remove a CCP device from the list
151  *
152  * @ccp: ccp_device struct pointer
153  *
154  * Remove this unit from the list of devices. If the next device
155  * up for use is this one, adjust the pointer. If this is the last
156  * device, NULL the pointer.
157  */
158 void ccp_del_device(struct ccp_device *ccp)
159 {
160 	unsigned long flags;
161 
162 	write_lock_irqsave(&ccp_unit_lock, flags);
163 	if (ccp_rr == ccp) {
164 		/* ccp_unit_lock is read/write; any read access
165 		 * will be suspended while we make changes to the
166 		 * list and RR pointer.
167 		 */
168 		if (list_is_last(&ccp_rr->entry, &ccp_units))
169 			ccp_rr = list_first_entry(&ccp_units, struct ccp_device,
170 						  entry);
171 		else
172 			ccp_rr = list_next_entry(ccp_rr, entry);
173 	}
174 	list_del(&ccp->entry);
175 	if (list_empty(&ccp_units))
176 		ccp_rr = NULL;
177 	write_unlock_irqrestore(&ccp_unit_lock, flags);
178 }
179 
180 
181 
182 int ccp_register_rng(struct ccp_device *ccp)
183 {
184 	int ret = 0;
185 
186 	dev_dbg(ccp->dev, "Registering RNG...\n");
187 	/* Register an RNG */
188 	ccp->hwrng.name = ccp->rngname;
189 	ccp->hwrng.read = ccp_trng_read;
190 	ret = hwrng_register(&ccp->hwrng);
191 	if (ret)
192 		dev_err(ccp->dev, "error registering hwrng (%d)\n", ret);
193 
194 	return ret;
195 }
196 
197 void ccp_unregister_rng(struct ccp_device *ccp)
198 {
199 	if (ccp->hwrng.name)
200 		hwrng_unregister(&ccp->hwrng);
201 }
202 
203 static struct ccp_device *ccp_get_device(void)
204 {
205 	unsigned long flags;
206 	struct ccp_device *dp = NULL;
207 
208 	/* We round-robin through the unit list.
209 	 * The (ccp_rr) pointer refers to the next unit to use.
210 	 */
211 	read_lock_irqsave(&ccp_unit_lock, flags);
212 	if (!list_empty(&ccp_units)) {
213 		spin_lock(&ccp_rr_lock);
214 		dp = ccp_rr;
215 		if (list_is_last(&ccp_rr->entry, &ccp_units))
216 			ccp_rr = list_first_entry(&ccp_units, struct ccp_device,
217 						  entry);
218 		else
219 			ccp_rr = list_next_entry(ccp_rr, entry);
220 		spin_unlock(&ccp_rr_lock);
221 	}
222 	read_unlock_irqrestore(&ccp_unit_lock, flags);
223 
224 	return dp;
225 }
226 
227 /**
228  * ccp_present - check if a CCP device is present
229  *
230  * Returns zero if a CCP device is present, -ENODEV otherwise.
231  */
232 int ccp_present(void)
233 {
234 	unsigned long flags;
235 	int ret;
236 
237 	read_lock_irqsave(&ccp_unit_lock, flags);
238 	ret = list_empty(&ccp_units);
239 	read_unlock_irqrestore(&ccp_unit_lock, flags);
240 
241 	return ret ? -ENODEV : 0;
242 }
243 EXPORT_SYMBOL_GPL(ccp_present);
244 
245 /**
246  * ccp_version - get the version of the CCP device
247  *
248  * Returns the version from the first unit on the list;
249  * otherwise a zero if no CCP device is present
250  */
251 unsigned int ccp_version(void)
252 {
253 	struct ccp_device *dp;
254 	unsigned long flags;
255 	int ret = 0;
256 
257 	read_lock_irqsave(&ccp_unit_lock, flags);
258 	if (!list_empty(&ccp_units)) {
259 		dp = list_first_entry(&ccp_units, struct ccp_device, entry);
260 		ret = dp->vdata->version;
261 	}
262 	read_unlock_irqrestore(&ccp_unit_lock, flags);
263 
264 	return ret;
265 }
266 EXPORT_SYMBOL_GPL(ccp_version);
267 
268 /**
269  * ccp_enqueue_cmd - queue an operation for processing by the CCP
270  *
271  * @cmd: ccp_cmd struct to be processed
272  *
273  * Queue a cmd to be processed by the CCP. If queueing the cmd
274  * would exceed the defined length of the cmd queue the cmd will
275  * only be queued if the CCP_CMD_MAY_BACKLOG flag is set and will
276  * result in a return code of -EBUSY.
277  *
278  * The callback routine specified in the ccp_cmd struct will be
279  * called to notify the caller of completion (if the cmd was not
280  * backlogged) or advancement out of the backlog. If the cmd has
281  * advanced out of the backlog the "err" value of the callback
282  * will be -EINPROGRESS. Any other "err" value during callback is
283  * the result of the operation.
284  *
285  * The cmd has been successfully queued if:
286  *   the return code is -EINPROGRESS or
287  *   the return code is -EBUSY and CCP_CMD_MAY_BACKLOG flag is set
288  */
289 int ccp_enqueue_cmd(struct ccp_cmd *cmd)
290 {
291 	struct ccp_device *ccp;
292 	unsigned long flags;
293 	unsigned int i;
294 	int ret;
295 
296 	/* Some commands might need to be sent to a specific device */
297 	ccp = cmd->ccp ? cmd->ccp : ccp_get_device();
298 
299 	if (!ccp)
300 		return -ENODEV;
301 
302 	/* Caller must supply a callback routine */
303 	if (!cmd->callback)
304 		return -EINVAL;
305 
306 	cmd->ccp = ccp;
307 
308 	spin_lock_irqsave(&ccp->cmd_lock, flags);
309 
310 	i = ccp->cmd_q_count;
311 
312 	if (ccp->cmd_count >= MAX_CMD_QLEN) {
313 		if (cmd->flags & CCP_CMD_MAY_BACKLOG) {
314 			ret = -EBUSY;
315 			list_add_tail(&cmd->entry, &ccp->backlog);
316 		} else {
317 			ret = -ENOSPC;
318 		}
319 	} else {
320 		ret = -EINPROGRESS;
321 		ccp->cmd_count++;
322 		list_add_tail(&cmd->entry, &ccp->cmd);
323 
324 		/* Find an idle queue */
325 		if (!ccp->suspending) {
326 			for (i = 0; i < ccp->cmd_q_count; i++) {
327 				if (ccp->cmd_q[i].active)
328 					continue;
329 
330 				break;
331 			}
332 		}
333 	}
334 
335 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
336 
337 	/* If we found an idle queue, wake it up */
338 	if (i < ccp->cmd_q_count)
339 		wake_up_process(ccp->cmd_q[i].kthread);
340 
341 	return ret;
342 }
343 EXPORT_SYMBOL_GPL(ccp_enqueue_cmd);
344 
345 static void ccp_do_cmd_backlog(struct work_struct *work)
346 {
347 	struct ccp_cmd *cmd = container_of(work, struct ccp_cmd, work);
348 	struct ccp_device *ccp = cmd->ccp;
349 	unsigned long flags;
350 	unsigned int i;
351 
352 	cmd->callback(cmd->data, -EINPROGRESS);
353 
354 	spin_lock_irqsave(&ccp->cmd_lock, flags);
355 
356 	ccp->cmd_count++;
357 	list_add_tail(&cmd->entry, &ccp->cmd);
358 
359 	/* Find an idle queue */
360 	for (i = 0; i < ccp->cmd_q_count; i++) {
361 		if (ccp->cmd_q[i].active)
362 			continue;
363 
364 		break;
365 	}
366 
367 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
368 
369 	/* If we found an idle queue, wake it up */
370 	if (i < ccp->cmd_q_count)
371 		wake_up_process(ccp->cmd_q[i].kthread);
372 }
373 
374 static struct ccp_cmd *ccp_dequeue_cmd(struct ccp_cmd_queue *cmd_q)
375 {
376 	struct ccp_device *ccp = cmd_q->ccp;
377 	struct ccp_cmd *cmd = NULL;
378 	struct ccp_cmd *backlog = NULL;
379 	unsigned long flags;
380 
381 	spin_lock_irqsave(&ccp->cmd_lock, flags);
382 
383 	cmd_q->active = 0;
384 
385 	if (ccp->suspending) {
386 		cmd_q->suspended = 1;
387 
388 		spin_unlock_irqrestore(&ccp->cmd_lock, flags);
389 		wake_up_interruptible(&ccp->suspend_queue);
390 
391 		return NULL;
392 	}
393 
394 	if (ccp->cmd_count) {
395 		cmd_q->active = 1;
396 
397 		cmd = list_first_entry(&ccp->cmd, struct ccp_cmd, entry);
398 		list_del(&cmd->entry);
399 
400 		ccp->cmd_count--;
401 	}
402 
403 	if (!list_empty(&ccp->backlog)) {
404 		backlog = list_first_entry(&ccp->backlog, struct ccp_cmd,
405 					   entry);
406 		list_del(&backlog->entry);
407 	}
408 
409 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
410 
411 	if (backlog) {
412 		INIT_WORK(&backlog->work, ccp_do_cmd_backlog);
413 		schedule_work(&backlog->work);
414 	}
415 
416 	return cmd;
417 }
418 
419 static void ccp_do_cmd_complete(unsigned long data)
420 {
421 	struct ccp_tasklet_data *tdata = (struct ccp_tasklet_data *)data;
422 	struct ccp_cmd *cmd = tdata->cmd;
423 
424 	cmd->callback(cmd->data, cmd->ret);
425 
426 	complete(&tdata->completion);
427 }
428 
429 /**
430  * ccp_cmd_queue_thread - create a kernel thread to manage a CCP queue
431  *
432  * @data: thread-specific data
433  */
434 int ccp_cmd_queue_thread(void *data)
435 {
436 	struct ccp_cmd_queue *cmd_q = (struct ccp_cmd_queue *)data;
437 	struct ccp_cmd *cmd;
438 	struct ccp_tasklet_data tdata;
439 	struct tasklet_struct tasklet;
440 
441 	tasklet_init(&tasklet, ccp_do_cmd_complete, (unsigned long)&tdata);
442 
443 	set_current_state(TASK_INTERRUPTIBLE);
444 	while (!kthread_should_stop()) {
445 		schedule();
446 
447 		set_current_state(TASK_INTERRUPTIBLE);
448 
449 		cmd = ccp_dequeue_cmd(cmd_q);
450 		if (!cmd)
451 			continue;
452 
453 		__set_current_state(TASK_RUNNING);
454 
455 		/* Execute the command */
456 		cmd->ret = ccp_run_cmd(cmd_q, cmd);
457 
458 		/* Schedule the completion callback */
459 		tdata.cmd = cmd;
460 		init_completion(&tdata.completion);
461 		tasklet_schedule(&tasklet);
462 		wait_for_completion(&tdata.completion);
463 	}
464 
465 	__set_current_state(TASK_RUNNING);
466 
467 	return 0;
468 }
469 
470 /**
471  * ccp_alloc_struct - allocate and initialize the ccp_device struct
472  *
473  * @dev: device struct of the CCP
474  */
475 struct ccp_device *ccp_alloc_struct(struct sp_device *sp)
476 {
477 	struct device *dev = sp->dev;
478 	struct ccp_device *ccp;
479 
480 	ccp = devm_kzalloc(dev, sizeof(*ccp), GFP_KERNEL);
481 	if (!ccp)
482 		return NULL;
483 	ccp->dev = dev;
484 	ccp->sp = sp;
485 	ccp->axcache = sp->axcache;
486 
487 	INIT_LIST_HEAD(&ccp->cmd);
488 	INIT_LIST_HEAD(&ccp->backlog);
489 
490 	spin_lock_init(&ccp->cmd_lock);
491 	mutex_init(&ccp->req_mutex);
492 	mutex_init(&ccp->sb_mutex);
493 	ccp->sb_count = KSB_COUNT;
494 	ccp->sb_start = 0;
495 
496 	/* Initialize the wait queues */
497 	init_waitqueue_head(&ccp->sb_queue);
498 	init_waitqueue_head(&ccp->suspend_queue);
499 
500 	snprintf(ccp->name, MAX_CCP_NAME_LEN, "ccp-%u", sp->ord);
501 	snprintf(ccp->rngname, MAX_CCP_NAME_LEN, "ccp-%u-rng", sp->ord);
502 
503 	return ccp;
504 }
505 
506 int ccp_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
507 {
508 	struct ccp_device *ccp = container_of(rng, struct ccp_device, hwrng);
509 	u32 trng_value;
510 	int len = min_t(int, sizeof(trng_value), max);
511 
512 	/* Locking is provided by the caller so we can update device
513 	 * hwrng-related fields safely
514 	 */
515 	trng_value = ioread32(ccp->io_regs + TRNG_OUT_REG);
516 	if (!trng_value) {
517 		/* Zero is returned if not data is available or if a
518 		 * bad-entropy error is present. Assume an error if
519 		 * we exceed TRNG_RETRIES reads of zero.
520 		 */
521 		if (ccp->hwrng_retries++ > TRNG_RETRIES)
522 			return -EIO;
523 
524 		return 0;
525 	}
526 
527 	/* Reset the counter and save the rng value */
528 	ccp->hwrng_retries = 0;
529 	memcpy(data, &trng_value, len);
530 
531 	return len;
532 }
533 
534 #ifdef CONFIG_PM
535 bool ccp_queues_suspended(struct ccp_device *ccp)
536 {
537 	unsigned int suspended = 0;
538 	unsigned long flags;
539 	unsigned int i;
540 
541 	spin_lock_irqsave(&ccp->cmd_lock, flags);
542 
543 	for (i = 0; i < ccp->cmd_q_count; i++)
544 		if (ccp->cmd_q[i].suspended)
545 			suspended++;
546 
547 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
548 
549 	return ccp->cmd_q_count == suspended;
550 }
551 
552 int ccp_dev_suspend(struct sp_device *sp, pm_message_t state)
553 {
554 	struct ccp_device *ccp = sp->ccp_data;
555 	unsigned long flags;
556 	unsigned int i;
557 
558 	spin_lock_irqsave(&ccp->cmd_lock, flags);
559 
560 	ccp->suspending = 1;
561 
562 	/* Wake all the queue kthreads to prepare for suspend */
563 	for (i = 0; i < ccp->cmd_q_count; i++)
564 		wake_up_process(ccp->cmd_q[i].kthread);
565 
566 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
567 
568 	/* Wait for all queue kthreads to say they're done */
569 	while (!ccp_queues_suspended(ccp))
570 		wait_event_interruptible(ccp->suspend_queue,
571 					 ccp_queues_suspended(ccp));
572 
573 	return 0;
574 }
575 
576 int ccp_dev_resume(struct sp_device *sp)
577 {
578 	struct ccp_device *ccp = sp->ccp_data;
579 	unsigned long flags;
580 	unsigned int i;
581 
582 	spin_lock_irqsave(&ccp->cmd_lock, flags);
583 
584 	ccp->suspending = 0;
585 
586 	/* Wake up all the kthreads */
587 	for (i = 0; i < ccp->cmd_q_count; i++) {
588 		ccp->cmd_q[i].suspended = 0;
589 		wake_up_process(ccp->cmd_q[i].kthread);
590 	}
591 
592 	spin_unlock_irqrestore(&ccp->cmd_lock, flags);
593 
594 	return 0;
595 }
596 #endif
597 
598 int ccp_dev_init(struct sp_device *sp)
599 {
600 	struct device *dev = sp->dev;
601 	struct ccp_device *ccp;
602 	int ret;
603 
604 	/*
605 	 * Check how many we have so far, and stop after reaching
606 	 * that number
607 	 */
608 	if (atomic_inc_return(&dev_count) > max_devs)
609 		return 0; /* don't fail the load */
610 
611 	ret = -ENOMEM;
612 	ccp = ccp_alloc_struct(sp);
613 	if (!ccp)
614 		goto e_err;
615 	sp->ccp_data = ccp;
616 
617 	if (!nqueues || (nqueues > MAX_HW_QUEUES))
618 		ccp->max_q_count = MAX_HW_QUEUES;
619 	else
620 		ccp->max_q_count = nqueues;
621 
622 	ccp->vdata = (struct ccp_vdata *)sp->dev_vdata->ccp_vdata;
623 	if (!ccp->vdata || !ccp->vdata->version) {
624 		ret = -ENODEV;
625 		dev_err(dev, "missing driver data\n");
626 		goto e_err;
627 	}
628 
629 	ccp->use_tasklet = sp->use_tasklet;
630 
631 	ccp->io_regs = sp->io_map + ccp->vdata->offset;
632 	if (ccp->vdata->setup)
633 		ccp->vdata->setup(ccp);
634 
635 	ret = ccp->vdata->perform->init(ccp);
636 	if (ret)
637 		goto e_err;
638 
639 	dev_notice(dev, "ccp enabled\n");
640 
641 	return 0;
642 
643 e_err:
644 	sp->ccp_data = NULL;
645 
646 	dev_notice(dev, "ccp initialization failed\n");
647 
648 	return ret;
649 }
650 
651 void ccp_dev_destroy(struct sp_device *sp)
652 {
653 	struct ccp_device *ccp = sp->ccp_data;
654 
655 	if (!ccp)
656 		return;
657 
658 	ccp->vdata->perform->destroy(ccp);
659 }
660