1 /* 2 * System Trace Module (STM) master/channel allocation policy management 3 * Copyright (c) 2014, Intel Corporation. 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms and conditions of the GNU General Public License, 7 * version 2, as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 12 * more details. 13 * 14 * A master/channel allocation policy allows mapping string identifiers to 15 * master and channel ranges, where allocation can be done. 16 */ 17 18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 19 20 #include <linux/types.h> 21 #include <linux/module.h> 22 #include <linux/device.h> 23 #include <linux/configfs.h> 24 #include <linux/slab.h> 25 #include <linux/stm.h> 26 #include "stm.h" 27 28 /* 29 * STP Master/Channel allocation policy configfs layout. 30 */ 31 32 struct stp_policy { 33 struct config_group group; 34 struct stm_device *stm; 35 }; 36 37 struct stp_policy_node { 38 struct config_group group; 39 struct stp_policy *policy; 40 unsigned int first_master; 41 unsigned int last_master; 42 unsigned int first_channel; 43 unsigned int last_channel; 44 }; 45 46 static struct configfs_subsystem stp_policy_subsys; 47 48 void stp_policy_node_get_ranges(struct stp_policy_node *policy_node, 49 unsigned int *mstart, unsigned int *mend, 50 unsigned int *cstart, unsigned int *cend) 51 { 52 *mstart = policy_node->first_master; 53 *mend = policy_node->last_master; 54 *cstart = policy_node->first_channel; 55 *cend = policy_node->last_channel; 56 } 57 58 static inline char *stp_policy_node_name(struct stp_policy_node *policy_node) 59 { 60 return policy_node->group.cg_item.ci_name ? : "<none>"; 61 } 62 63 static inline struct stp_policy *to_stp_policy(struct config_item *item) 64 { 65 return item ? 66 container_of(to_config_group(item), struct stp_policy, group) : 67 NULL; 68 } 69 70 static inline struct stp_policy_node * 71 to_stp_policy_node(struct config_item *item) 72 { 73 return item ? 74 container_of(to_config_group(item), struct stp_policy_node, 75 group) : 76 NULL; 77 } 78 79 static ssize_t 80 stp_policy_node_masters_show(struct config_item *item, char *page) 81 { 82 struct stp_policy_node *policy_node = to_stp_policy_node(item); 83 ssize_t count; 84 85 count = sprintf(page, "%u %u\n", policy_node->first_master, 86 policy_node->last_master); 87 88 return count; 89 } 90 91 static ssize_t 92 stp_policy_node_masters_store(struct config_item *item, const char *page, 93 size_t count) 94 { 95 struct stp_policy_node *policy_node = to_stp_policy_node(item); 96 unsigned int first, last; 97 struct stm_device *stm; 98 char *p = (char *)page; 99 ssize_t ret = -ENODEV; 100 101 if (sscanf(p, "%u %u", &first, &last) != 2) 102 return -EINVAL; 103 104 mutex_lock(&stp_policy_subsys.su_mutex); 105 stm = policy_node->policy->stm; 106 if (!stm) 107 goto unlock; 108 109 /* must be within [sw_start..sw_end], which is an inclusive range */ 110 if (first > INT_MAX || last > INT_MAX || first > last || 111 first < stm->data->sw_start || 112 last > stm->data->sw_end) { 113 ret = -ERANGE; 114 goto unlock; 115 } 116 117 ret = count; 118 policy_node->first_master = first; 119 policy_node->last_master = last; 120 121 unlock: 122 mutex_unlock(&stp_policy_subsys.su_mutex); 123 124 return ret; 125 } 126 127 static ssize_t 128 stp_policy_node_channels_show(struct config_item *item, char *page) 129 { 130 struct stp_policy_node *policy_node = to_stp_policy_node(item); 131 ssize_t count; 132 133 count = sprintf(page, "%u %u\n", policy_node->first_channel, 134 policy_node->last_channel); 135 136 return count; 137 } 138 139 static ssize_t 140 stp_policy_node_channels_store(struct config_item *item, const char *page, 141 size_t count) 142 { 143 struct stp_policy_node *policy_node = to_stp_policy_node(item); 144 unsigned int first, last; 145 struct stm_device *stm; 146 char *p = (char *)page; 147 ssize_t ret = -ENODEV; 148 149 if (sscanf(p, "%u %u", &first, &last) != 2) 150 return -EINVAL; 151 152 mutex_lock(&stp_policy_subsys.su_mutex); 153 stm = policy_node->policy->stm; 154 if (!stm) 155 goto unlock; 156 157 if (first > INT_MAX || last > INT_MAX || first > last || 158 last >= stm->data->sw_nchannels) { 159 ret = -ERANGE; 160 goto unlock; 161 } 162 163 ret = count; 164 policy_node->first_channel = first; 165 policy_node->last_channel = last; 166 167 unlock: 168 mutex_unlock(&stp_policy_subsys.su_mutex); 169 170 return ret; 171 } 172 173 static void stp_policy_node_release(struct config_item *item) 174 { 175 kfree(to_stp_policy_node(item)); 176 } 177 178 static struct configfs_item_operations stp_policy_node_item_ops = { 179 .release = stp_policy_node_release, 180 }; 181 182 CONFIGFS_ATTR(stp_policy_node_, masters); 183 CONFIGFS_ATTR(stp_policy_node_, channels); 184 185 static struct configfs_attribute *stp_policy_node_attrs[] = { 186 &stp_policy_node_attr_masters, 187 &stp_policy_node_attr_channels, 188 NULL, 189 }; 190 191 static struct config_item_type stp_policy_type; 192 static struct config_item_type stp_policy_node_type; 193 194 static struct config_group * 195 stp_policy_node_make(struct config_group *group, const char *name) 196 { 197 struct stp_policy_node *policy_node, *parent_node; 198 struct stp_policy *policy; 199 200 if (group->cg_item.ci_type == &stp_policy_type) { 201 policy = container_of(group, struct stp_policy, group); 202 } else { 203 parent_node = container_of(group, struct stp_policy_node, 204 group); 205 policy = parent_node->policy; 206 } 207 208 if (!policy->stm) 209 return ERR_PTR(-ENODEV); 210 211 policy_node = kzalloc(sizeof(struct stp_policy_node), GFP_KERNEL); 212 if (!policy_node) 213 return ERR_PTR(-ENOMEM); 214 215 config_group_init_type_name(&policy_node->group, name, 216 &stp_policy_node_type); 217 218 policy_node->policy = policy; 219 220 /* default values for the attributes */ 221 policy_node->first_master = policy->stm->data->sw_start; 222 policy_node->last_master = policy->stm->data->sw_end; 223 policy_node->first_channel = 0; 224 policy_node->last_channel = policy->stm->data->sw_nchannels - 1; 225 226 return &policy_node->group; 227 } 228 229 static void 230 stp_policy_node_drop(struct config_group *group, struct config_item *item) 231 { 232 config_item_put(item); 233 } 234 235 static struct configfs_group_operations stp_policy_node_group_ops = { 236 .make_group = stp_policy_node_make, 237 .drop_item = stp_policy_node_drop, 238 }; 239 240 static struct config_item_type stp_policy_node_type = { 241 .ct_item_ops = &stp_policy_node_item_ops, 242 .ct_group_ops = &stp_policy_node_group_ops, 243 .ct_attrs = stp_policy_node_attrs, 244 .ct_owner = THIS_MODULE, 245 }; 246 247 /* 248 * Root group: policies. 249 */ 250 static ssize_t stp_policy_device_show(struct config_item *item, 251 char *page) 252 { 253 struct stp_policy *policy = to_stp_policy(item); 254 ssize_t count; 255 256 count = sprintf(page, "%s\n", 257 (policy && policy->stm) ? 258 policy->stm->data->name : 259 "<none>"); 260 261 return count; 262 } 263 264 CONFIGFS_ATTR_RO(stp_policy_, device); 265 266 static struct configfs_attribute *stp_policy_attrs[] = { 267 &stp_policy_attr_device, 268 NULL, 269 }; 270 271 void stp_policy_unbind(struct stp_policy *policy) 272 { 273 struct stm_device *stm = policy->stm; 274 275 if (WARN_ON_ONCE(!policy->stm)) 276 return; 277 278 mutex_lock(&stm->policy_mutex); 279 stm->policy = NULL; 280 mutex_unlock(&stm->policy_mutex); 281 282 policy->stm = NULL; 283 284 stm_put_device(stm); 285 } 286 287 static void stp_policy_release(struct config_item *item) 288 { 289 struct stp_policy *policy = to_stp_policy(item); 290 291 stp_policy_unbind(policy); 292 kfree(policy); 293 } 294 295 static struct configfs_item_operations stp_policy_item_ops = { 296 .release = stp_policy_release, 297 }; 298 299 static struct configfs_group_operations stp_policy_group_ops = { 300 .make_group = stp_policy_node_make, 301 }; 302 303 static struct config_item_type stp_policy_type = { 304 .ct_item_ops = &stp_policy_item_ops, 305 .ct_group_ops = &stp_policy_group_ops, 306 .ct_attrs = stp_policy_attrs, 307 .ct_owner = THIS_MODULE, 308 }; 309 310 static struct config_group * 311 stp_policies_make(struct config_group *group, const char *name) 312 { 313 struct config_group *ret; 314 struct stm_device *stm; 315 char *devname, *p; 316 317 devname = kasprintf(GFP_KERNEL, "%s", name); 318 if (!devname) 319 return ERR_PTR(-ENOMEM); 320 321 /* 322 * node must look like <device_name>.<policy_name>, where 323 * <device_name> is the name of an existing stm device and 324 * <policy_name> is an arbitrary string 325 */ 326 p = strchr(devname, '.'); 327 if (!p) { 328 kfree(devname); 329 return ERR_PTR(-EINVAL); 330 } 331 332 *p++ = '\0'; 333 334 stm = stm_find_device(devname); 335 kfree(devname); 336 337 if (!stm) 338 return ERR_PTR(-ENODEV); 339 340 mutex_lock(&stm->policy_mutex); 341 if (stm->policy) { 342 ret = ERR_PTR(-EBUSY); 343 goto unlock_policy; 344 } 345 346 stm->policy = kzalloc(sizeof(*stm->policy), GFP_KERNEL); 347 if (!stm->policy) { 348 ret = ERR_PTR(-ENOMEM); 349 goto unlock_policy; 350 } 351 352 config_group_init_type_name(&stm->policy->group, name, 353 &stp_policy_type); 354 stm->policy->stm = stm; 355 356 ret = &stm->policy->group; 357 358 unlock_policy: 359 mutex_unlock(&stm->policy_mutex); 360 361 if (IS_ERR(ret)) 362 stm_put_device(stm); 363 364 return ret; 365 } 366 367 static struct configfs_group_operations stp_policies_group_ops = { 368 .make_group = stp_policies_make, 369 }; 370 371 static struct config_item_type stp_policies_type = { 372 .ct_group_ops = &stp_policies_group_ops, 373 .ct_owner = THIS_MODULE, 374 }; 375 376 static struct configfs_subsystem stp_policy_subsys = { 377 .su_group = { 378 .cg_item = { 379 .ci_namebuf = "stp-policy", 380 .ci_type = &stp_policies_type, 381 }, 382 }, 383 }; 384 385 /* 386 * Lock the policy mutex from the outside 387 */ 388 static struct stp_policy_node * 389 __stp_policy_node_lookup(struct stp_policy *policy, char *s) 390 { 391 struct stp_policy_node *policy_node, *ret; 392 struct list_head *head = &policy->group.cg_children; 393 struct config_item *item; 394 char *start, *end = s; 395 396 if (list_empty(head)) 397 return NULL; 398 399 /* return the first entry if everything else fails */ 400 item = list_entry(head->next, struct config_item, ci_entry); 401 ret = to_stp_policy_node(item); 402 403 next: 404 for (;;) { 405 start = strsep(&end, "/"); 406 if (!start) 407 break; 408 409 if (!*start) 410 continue; 411 412 list_for_each_entry(item, head, ci_entry) { 413 policy_node = to_stp_policy_node(item); 414 415 if (!strcmp(start, 416 policy_node->group.cg_item.ci_name)) { 417 ret = policy_node; 418 419 if (!end) 420 goto out; 421 422 head = &policy_node->group.cg_children; 423 goto next; 424 } 425 } 426 break; 427 } 428 429 out: 430 return ret; 431 } 432 433 434 struct stp_policy_node * 435 stp_policy_node_lookup(struct stm_device *stm, char *s) 436 { 437 struct stp_policy_node *policy_node = NULL; 438 439 mutex_lock(&stp_policy_subsys.su_mutex); 440 441 mutex_lock(&stm->policy_mutex); 442 if (stm->policy) 443 policy_node = __stp_policy_node_lookup(stm->policy, s); 444 mutex_unlock(&stm->policy_mutex); 445 446 if (policy_node) 447 config_item_get(&policy_node->group.cg_item); 448 mutex_unlock(&stp_policy_subsys.su_mutex); 449 450 return policy_node; 451 } 452 453 void stp_policy_node_put(struct stp_policy_node *policy_node) 454 { 455 config_item_put(&policy_node->group.cg_item); 456 } 457 458 int __init stp_configfs_init(void) 459 { 460 int err; 461 462 config_group_init(&stp_policy_subsys.su_group); 463 mutex_init(&stp_policy_subsys.su_mutex); 464 err = configfs_register_subsystem(&stp_policy_subsys); 465 466 return err; 467 } 468 469 void __exit stp_configfs_exit(void) 470 { 471 configfs_unregister_subsystem(&stp_policy_subsys); 472 } 473