summaryrefslogtreecommitdiffstats
path: root/drivers/hwtracing/stm/policy.c
blob: 33e9a1b6ea7c2b9571574dc7a971085b043813a8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
/*
 * System Trace Module (STM) master/channel allocation policy management
 * Copyright (c) 2014, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * A master/channel allocation policy allows mapping string identifiers to
 * master and channel ranges, where allocation can be done.
 */

#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

#include <linux/types.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/configfs.h>
#include <linux/slab.h>
#include <linux/stm.h>
#include "stm.h"

/*
 * STP Master/Channel allocation policy configfs layout.
 */

struct stp_policy {
	struct config_group	group;
	struct stm_device	*stm;
};

struct stp_policy_node {
	struct config_group	group;
	struct stp_policy	*policy;
	unsigned int		first_master;
	unsigned int		last_master;
	unsigned int		first_channel;
	unsigned int		last_channel;
};

static struct configfs_subsystem stp_policy_subsys;

void stp_policy_node_get_ranges(struct stp_policy_node *policy_node,
				unsigned int *mstart, unsigned int *mend,
				unsigned int *cstart, unsigned int *cend)
{
	*mstart	= policy_node->first_master;
	*mend	= policy_node->last_master;
	*cstart	= policy_node->first_channel;
	*cend	= policy_node->last_channel;
}

static inline char *stp_policy_node_name(struct stp_policy_node *policy_node)
{
	return policy_node->group.cg_item.ci_name ? : "<none>";
}

static inline struct stp_policy *to_stp_policy(struct config_item *item)
{
	return item ?
		container_of(to_config_group(item), struct stp_policy, group) :
		NULL;
}

static inline struct stp_policy_node *
to_stp_policy_node(struct config_item *item)
{
	return item ?
		container_of(to_config_group(item), struct stp_policy_node,
			     group) :
		NULL;
}

static ssize_t
stp_policy_node_masters_show(struct config_item *item, char *page)
{
	struct stp_policy_node *policy_node = to_stp_policy_node(item);
	ssize_t count;

	count = sprintf(page, "%u %u\n", policy_node->first_master,
			policy_node->last_master);

	return count;
}

static ssize_t
stp_policy_node_masters_store(struct config_item *item, const char *page,
			      size_t count)
{
	struct stp_policy_node *policy_node = to_stp_policy_node(item);
	unsigned int first, last;
	struct stm_device *stm;
	char *p = (char *)page;
	ssize_t ret = -ENODEV;

	if (sscanf(p, "%u %u", &first, &last) != 2)
		return -EINVAL;

	mutex_lock(&stp_policy_subsys.su_mutex);
	stm = policy_node->policy->stm;
	if (!stm)
		goto unlock;

	/* must be within [sw_start..sw_end], which is an inclusive range */
	if (first > last || first < stm->data->sw_start ||
	    last > stm->data->sw_end) {
		ret = -ERANGE;
		goto unlock;
	}

	ret = count;
	policy_node->first_master = first;
	policy_node->last_master = last;

unlock:
	mutex_unlock(&stp_policy_subsys.su_mutex);

	return ret;
}

static ssize_t
stp_policy_node_channels_show(struct config_item *item, char *page)
{
	struct stp_policy_node *policy_node = to_stp_policy_node(item);
	ssize_t count;

	count = sprintf(page, "%u %u\n", policy_node->first_channel,
			policy_node->last_channel);

	return count;
}

static ssize_t
stp_policy_node_channels_store(struct config_item *item, const char *page,
			       size_t count)
{
	struct stp_policy_node *policy_node = to_stp_policy_node(item);
	unsigned int first, last;
	struct stm_device *stm;
	char *p = (char *)page;
	ssize_t ret = -ENODEV;

	if (sscanf(p, "%u %u", &first, &last) != 2)
		return -EINVAL;

	mutex_lock(&stp_policy_subsys.su_mutex);
	stm = policy_node->policy->stm;
	if (!stm)
		goto unlock;

	if (first > INT_MAX || last > INT_MAX || first > last ||
	    last >= stm->data->sw_nchannels) {
		ret = -ERANGE;
		goto unlock;
	}

	ret = count;
	policy_node->first_channel = first;
	policy_node->last_channel = last;

unlock:
	mutex_unlock(&stp_policy_subsys.su_mutex);

	return ret;
}

static void stp_policy_node_release(struct config_item *item)
{
	kfree(to_stp_policy_node(item));
}

static struct configfs_item_operations stp_policy_node_item_ops = {
	.release		= stp_policy_node_release,
};

CONFIGFS_ATTR(stp_policy_node_, masters);
CONFIGFS_ATTR(stp_policy_node_, channels);

static struct configfs_attribute *stp_policy_node_attrs[] = {
	&stp_policy_node_attr_masters,
	&stp_policy_node_attr_channels,
	NULL,
};

static const struct config_item_type stp_policy_type;
static const struct config_item_type stp_policy_node_type;

static struct config_group *
stp_policy_node_make(struct config_group *group, const char *name)
{
	struct stp_policy_node *policy_node, *parent_node;
	struct stp_policy *policy;

	if (group->cg_item.ci_type == &stp_policy_type) {
		policy = container_of(group, struct stp_policy, group);
	} else {
		parent_node = container_of(group, struct stp_policy_node,
					   group);
		policy = parent_node->policy;
	}

	if (!policy->stm)
		return ERR_PTR(-ENODEV);

	policy_node = kzalloc(sizeof(struct stp_policy_node), GFP_KERNEL);
	if (!policy_node)
		return ERR_PTR(-ENOMEM);

	config_group_init_type_name(&policy_node->group, name,
				    &stp_policy_node_type);

	policy_node->policy = policy;

	/* default values for the attributes */
	policy_node->first_master = policy->stm->data->sw_start;
	policy_node->last_master = policy->stm->data->sw_end;
	policy_node->first_channel = 0;
	policy_node->last_channel = policy->stm->data->sw_nchannels - 1;

	return &policy_node->group;
}

static void
stp_policy_node_drop(struct config_group *group, struct config_item *item)
{
	config_item_put(item);
}

static struct configfs_group_operations stp_policy_node_group_ops = {
	.make_group	= stp_policy_node_make,
	.drop_item	= stp_policy_node_drop,
};

static const struct config_item_type stp_policy_node_type = {
	.ct_item_ops	= &stp_policy_node_item_ops,
	.ct_group_ops	= &stp_policy_node_group_ops,
	.ct_attrs	= stp_policy_node_attrs,
	.ct_owner	= THIS_MODULE,
};

/*
 * Root group: policies.
 */
static ssize_t stp_policy_device_show(struct config_item *item,
				      char *page)
{
	struct stp_policy *policy = to_stp_policy(item);
	ssize_t count;

	count = sprintf(page, "%s\n",
			(policy && policy->stm) ?
			policy->stm->data->name :
			"<none>");

	return count;
}

CONFIGFS_ATTR_RO(stp_policy_, device);

static struct configfs_attribute *stp_policy_attrs[] = {
	&stp_policy_attr_device,
	NULL,
};

void stp_policy_unbind(struct stp_policy *policy)
{
	struct stm_device *stm = policy->stm;

	/*
	 * stp_policy_release() will not call here if the policy is already
	 * unbound; other users should not either, as no link exists between
	 * this policy and anything else in that case
	 */
	if (WARN_ON_ONCE(!policy->stm))
		return;

	lockdep_assert_held(&stm->policy_mutex);

	stm->policy = NULL;
	policy->stm = NULL;

	stm_put_device(stm);
}

static void stp_policy_release(struct config_item *item)
{
	struct stp_policy *policy = to_stp_policy(item);
	struct stm_device *stm = policy->stm;

	/* a policy *can* be unbound and still exist in configfs tree */
	if (!stm)
		return;

	mutex_lock(&stm->policy_mutex);
	stp_policy_unbind(policy);
	mutex_unlock(&stm->policy_mutex);

	kfree(policy);
}

static struct configfs_item_operations stp_policy_item_ops = {
	.release		= stp_policy_release,
};

static struct configfs_group_operations stp_policy_group_ops = {
	.make_group	= stp_policy_node_make,
};

static const struct config_item_type stp_policy_type = {
	.ct_item_ops	= &stp_policy_item_ops,
	.ct_group_ops	= &stp_policy_group_ops,
	.ct_attrs	= stp_policy_attrs,
	.ct_owner	= THIS_MODULE,
};

static struct config_group *
stp_policies_make(struct config_group *group, const char *name)
{
	struct config_group *ret;
	struct stm_device *stm;
	char *devname, *p;

	devname = kasprintf(GFP_KERNEL, "%s", name);
	if (!devname)
		return ERR_PTR(-ENOMEM);

	/*
	 * node must look like <device_name>.<policy_name>, where
	 * <device_name> is the name of an existing stm device; may
	 *               contain dots;
	 * <policy_name> is an arbitrary string; may not contain dots
	 */
	p = strrchr(devname, '.');
	if (!p) {
		kfree(devname);
		return ERR_PTR(-EINVAL);
	}

	*p = '\0';

	stm = stm_find_device(devname);
	kfree(devname);

	if (!stm)
		return ERR_PTR(-ENODEV);

	mutex_lock(&stm->policy_mutex);
	if (stm->policy) {
		ret = ERR_PTR(-EBUSY);
		goto unlock_policy;
	}

	stm->policy = kzalloc(sizeof(*stm->policy), GFP_KERNEL);
	if (!stm->policy) {
		ret = ERR_PTR(-ENOMEM);
		goto unlock_policy;
	}

	config_group_init_type_name(&stm->policy->group, name,
				    &stp_policy_type);
	stm->policy->stm = stm;

	ret = &stm->policy->group;

unlock_policy:
	mutex_unlock(&stm->policy_mutex);

	if (IS_ERR(ret))
		stm_put_device(stm);

	return ret;
}

static struct configfs_group_operations stp_policies_group_ops = {
	.make_group	= stp_policies_make,
};

static const struct config_item_type stp_policies_type = {
	.ct_group_ops	= &stp_policies_group_ops,
	.ct_owner	= THIS_MODULE,
};

static struct configfs_subsystem stp_policy_subsys = {
	.su_group = {
		.cg_item = {
			.ci_namebuf	= "stp-policy",
			.ci_type	= &stp_policies_type,
		},
	},
};

/*
 * Lock the policy mutex from the outside
 */
static struct stp_policy_node *
__stp_policy_node_lookup(struct stp_policy *policy, char *s)
{
	struct stp_policy_node *policy_node, *ret;
	struct list_head *head = &policy->group.cg_children;
	struct config_item *item;
	char *start, *end = s;

	if (list_empty(head))
		return NULL;

	/* return the first entry if everything else fails */
	item = list_entry(head->next, struct config_item, ci_entry);
	ret = to_stp_policy_node(item);

next:
	for (;;) {
		start = strsep(&end, "/");
		if (!start)
			break;

		if (!*start)
			continue;

		list_for_each_entry(item, head, ci_entry) {
			policy_node = to_stp_policy_node(item);

			if (!strcmp(start,
				    policy_node->group.cg_item.ci_name)) {
				ret = policy_node;

				if (!end)
					goto out;

				head = &policy_node->group.cg_children;
				goto next;
			}
		}
		break;
	}

out:
	return ret;
}


struct stp_policy_node *
stp_policy_node_lookup(struct stm_device *stm, char *s)
{
	struct stp_policy_node *policy_node = NULL;

	mutex_lock(&stp_policy_subsys.su_mutex);

	mutex_lock(&stm->policy_mutex);
	if (stm->policy)
		policy_node = __stp_policy_node_lookup(stm->policy, s);
	mutex_unlock(&stm->policy_mutex);

	if (policy_node)
		config_item_get(&policy_node->group.cg_item);
	mutex_unlock(&stp_policy_subsys.su_mutex);

	return policy_node;
}

void stp_policy_node_put(struct stp_policy_node *policy_node)
{
	config_item_put(&policy_node->group.cg_item);
}

int __init stp_configfs_init(void)
{
	int err;

	config_group_init(&stp_policy_subsys.su_group);
	mutex_init(&stp_policy_subsys.su_mutex);
	err = configfs_register_subsystem(&stp_policy_subsys);

	return err;
}

void __exit stp_configfs_exit(void)
{
	configfs_unregister_subsystem(&stp_policy_subsys);
}