drivers/tee/optee/supp.c

   1 /*
   2  * Copyright (c) 2015, Linaro Limited
   3  *
   4  * This software is licensed under the terms of the GNU General Public
   5  * License version 2, as published by the Free Software Foundation, and
   6  * may be copied, distributed, and modified under those terms.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14 #include <linux/device.h>
  15 #include <linux/slab.h>
  16 #include <linux/uaccess.h>
  17 #include "optee_private.h"
  18
  19 struct optee_supp_req {
  20         struct list_head link;
  21
  22         bool in_queue;
  23         u32 func;
  24         u32 ret;
  25         size_t num_params;
  26         struct tee_param *param;
  27
  28         struct completion c;
  29 };
  30
  31 void optee_supp_init(struct optee_supp *supp)
  32 {
  33         memset(supp, 0, sizeof(*supp));
  34         mutex_init(&supp->mutex);
  35         init_completion(&supp->reqs_c);
  36         idr_init(&supp->idr);
  37         INIT_LIST_HEAD(&supp->reqs);
  38         supp->req_id = -1;
  39 }
  40
  41 void optee_supp_uninit(struct optee_supp *supp)
  42 {
  43         mutex_destroy(&supp->mutex);
  44         idr_destroy(&supp->idr);
  45 }
  46
  47 void optee_supp_release(struct optee_supp *supp)
  48 {
  49         int id;
  50         struct optee_supp_req *req;
  51         struct optee_supp_req *req_tmp;
  52
  53         mutex_lock(&supp->mutex);
  54
  55         /* Abort all request retrieved by supplicant */
  56         idr_for_each_entry(&supp->idr, req, id) {
  57                 idr_remove(&supp->idr, id);
  58                 req->ret = TEEC_ERROR_COMMUNICATION;
  59                 complete(&req->c);
  60         }
  61
  62         /* Abort all queued requests */
  63         list_for_each_entry_safe(req, req_tmp, &supp->reqs, link) {
  64                 list_del(&req->link);
  65                 req->in_queue = false;
  66                 req->ret = TEEC_ERROR_COMMUNICATION;
  67                 complete(&req->c);
  68         }
  69
  70         supp->ctx = NULL;
  71         supp->req_id = -1;
  72
  73         mutex_unlock(&supp->mutex);
  74 }
  75
  76 /**
  77  * optee_supp_thrd_req() - request service from supplicant
  78  * @ctx:        context doing the request
  79  * @func:       function requested
  80  * @num_params: number of elements in @param array
  81  * @param:      parameters for function
  82  *
  83  * Returns result of operation to be passed to secure world
  84  */
  85 u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
  86                         struct tee_param *param)
  87
  88 {
  89         struct optee *optee = tee_get_drvdata(ctx->teedev);
  90         struct optee_supp *supp = &optee->supp;
  91         struct optee_supp_req *req = kzalloc(sizeof(*req), GFP_KERNEL);
  92         bool interruptable;
  93         u32 ret;
  94
  95         if (!req)
  96                 return TEEC_ERROR_OUT_OF_MEMORY;
  97
  98         init_completion(&req->c);
  99         req->func = func;
 100         req->num_params = num_params;
 101         req->param = param;
 102
 103         /* Insert the request in the request list */
 104         mutex_lock(&supp->mutex);
 105         list_add_tail(&req->link, &supp->reqs);
 106         req->in_queue = true;
 107         mutex_unlock(&supp->mutex);
 108
 109         /* Tell an eventual waiter there's a new request */
 110         complete(&supp->reqs_c);
 111
 112         /*
 113          * Wait for supplicant to process and return result, once we've
 114          * returned from wait_for_completion(&req->c) successfully we have
 115          * exclusive access again.
 116          */
 117         while (wait_for_completion_interruptible(&req->c)) {
 118                 mutex_lock(&supp->mutex);
 119                 interruptable = !supp->ctx;
 120                 if (interruptable) {
 121                         /*
 122                          * There's no supplicant available and since the
 123                          * supp->mutex currently is held none can
 124                          * become available until the mutex released
 125                          * again.
 126                          *
 127                          * Interrupting an RPC to supplicant is only
 128                          * allowed as a way of slightly improving the user
 129                          * experience in case the supplicant hasn't been
 130                          * started yet. During normal operation the supplicant
 131                          * will serve all requests in a timely manner and
 132                          * interrupting then wouldn't make sense.
 133                          */
 134                         if (req->in_queue) {
 135                                 list_del(&req->link);
 136                                 req->in_queue = false;
 137                         }
 138                 }
 139                 mutex_unlock(&supp->mutex);
 140
 141                 if (interruptable) {
 142                         req->ret = TEEC_ERROR_COMMUNICATION;
 143                         break;
 144                 }
 145         }
 146
 147         ret = req->ret;
 148         kfree(req);
 149
 150         return ret;
 151 }
 152
 153 static struct optee_supp_req  *supp_pop_entry(struct optee_supp *supp,
 154                                               int num_params, int *id)
 155 {
 156         struct optee_supp_req *req;
 157
 158         if (supp->req_id != -1) {
 159                 /*
 160                  * Supplicant should not mix synchronous and asnynchronous
 161                  * requests.
 162                  */
 163                 return ERR_PTR(-EINVAL);
 164         }
 165
 166         if (list_empty(&supp->reqs))
 167                 return NULL;
 168
 169         req = list_first_entry(&supp->reqs, struct optee_supp_req, link);
 170
 171         if (num_params < req->num_params) {
 172                 /* Not enough room for parameters */
 173                 return ERR_PTR(-EINVAL);
 174         }
 175
 176         *id = idr_alloc(&supp->idr, req, 1, 0, GFP_KERNEL);
 177         if (*id < 0)
 178                 return ERR_PTR(-ENOMEM);
 179
 180         list_del(&req->link);
 181         req->in_queue = false;
 182
 183         return req;
 184 }
 185
 186 static int supp_check_recv_params(size_t num_params, struct tee_param *params,
 187                                   size_t *num_meta)
 188 {
 189         size_t n;
 190
 191         if (!num_params)
 192                 return -EINVAL;
 193
 194         /*
 195          * If there's memrefs we need to decrease those as they where
 196          * increased earlier and we'll even refuse to accept any below.
 197          */
 198         for (n = 0; n < num_params; n++)
 199                 if (tee_param_is_memref(params + n) && params[n].u.memref.shm)
 200                         tee_shm_put(params[n].u.memref.shm);
 201
 202         /*
 203          * We only expect parameters as TEE_IOCTL_PARAM_ATTR_TYPE_NONE with
 204          * or without the TEE_IOCTL_PARAM_ATTR_META bit set.
 205          */
 206         for (n = 0; n < num_params; n++)
 207                 if (params[n].attr &&
 208                     params[n].attr != TEE_IOCTL_PARAM_ATTR_META)
 209                         return -EINVAL;
 210
 211         /* At most we'll need one meta parameter so no need to check for more */
 212         if (params->attr == TEE_IOCTL_PARAM_ATTR_META)
 213                 *num_meta = 1;
 214         else
 215                 *num_meta = 0;
 216
 217         return 0;
 218 }
 219
 220 /**
 221  * optee_supp_recv() - receive request for supplicant
 222  * @ctx:        context receiving the request
 223  * @func:       requested function in supplicant
 224  * @num_params: number of elements allocated in @param, updated with number
 225  *              used elements
 226  * @param:      space for parameters for @func
 227  *
 228  * Returns 0 on success or <0 on failure
 229  */
 230 int optee_supp_recv(struct tee_context *ctx, u32 *func, u32 *num_params,
 231                     struct tee_param *param)
 232 {
 233         struct tee_device *teedev = ctx->teedev;
 234         struct optee *optee = tee_get_drvdata(teedev);
 235         struct optee_supp *supp = &optee->supp;
 236         struct optee_supp_req *req = NULL;
 237         int id;
 238         size_t num_meta;
 239         int rc;
 240
 241         rc = supp_check_recv_params(*num_params, param, &num_meta);
 242         if (rc)
 243                 return rc;
 244
 245         while (true) {
 246                 mutex_lock(&supp->mutex);
 247                 req = supp_pop_entry(supp, *num_params - num_meta, &id);
 248                 mutex_unlock(&supp->mutex);
 249
 250                 if (req) {
 251                         if (IS_ERR(req))
 252                                 return PTR_ERR(req);
 253                         break;
 254                 }
 255
 256                 /*
 257                  * If we didn't get a request we'll block in
 258                  * wait_for_completion() to avoid needless spinning.
 259                  *
 260                  * This is where supplicant will be hanging most of
 261                  * the time, let's make this interruptable so we
 262                  * can easily restart supplicant if needed.
 263                  */
 264                 if (wait_for_completion_interruptible(&supp->reqs_c))
 265                         return -ERESTARTSYS;
 266         }
 267
 268         if (num_meta) {
 269                 /*
 270                  * tee-supplicant support meta parameters -> requsts can be
 271                  * processed asynchronously.
 272                  */
 273                 param->attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT |
 274                               TEE_IOCTL_PARAM_ATTR_META;
 275                 param->u.value.a = id;
 276                 param->u.value.b = 0;
 277                 param->u.value.c = 0;
 278         } else {
 279                 mutex_lock(&supp->mutex);
 280                 supp->req_id = id;
 281                 mutex_unlock(&supp->mutex);
 282         }
 283
 284         *func = req->func;
 285         *num_params = req->num_params + num_meta;
 286         memcpy(param + num_meta, req->param,
 287                sizeof(struct tee_param) * req->num_params);
 288
 289         return 0;
 290 }
 291
 292 static struct optee_supp_req *supp_pop_req(struct optee_supp *supp,
 293                                            size_t num_params,
 294                                            struct tee_param *param,
 295                                            size_t *num_meta)
 296 {
 297         struct optee_supp_req *req;
 298         int id;
 299         size_t nm;
 300         const u32 attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT |
 301                          TEE_IOCTL_PARAM_ATTR_META;
 302
 303         if (!num_params)
 304                 return ERR_PTR(-EINVAL);
 305
 306         if (supp->req_id == -1) {
 307                 if (param->attr != attr)
 308                         return ERR_PTR(-EINVAL);
 309                 id = param->u.value.a;
 310                 nm = 1;
 311         } else {
 312                 id = supp->req_id;
 313                 nm = 0;
 314         }
 315
 316         req = idr_find(&supp->idr, id);
 317         if (!req)
 318                 return ERR_PTR(-ENOENT);
 319
 320         if ((num_params - nm) != req->num_params)
 321                 return ERR_PTR(-EINVAL);
 322
 323         idr_remove(&supp->idr, id);
 324         supp->req_id = -1;
 325         *num_meta = nm;
 326
 327         return req;
 328 }
 329
 330 /**
 331  * optee_supp_send() - send result of request from supplicant
 332  * @ctx:        context sending result
 333  * @ret:        return value of request
 334  * @num_params: number of parameters returned
 335  * @param:      returned parameters
 336  *
 337  * Returns 0 on success or <0 on failure.
 338  */
 339 int optee_supp_send(struct tee_context *ctx, u32 ret, u32 num_params,
 340                     struct tee_param *param)
 341 {
 342         struct tee_device *teedev = ctx->teedev;
 343         struct optee *optee = tee_get_drvdata(teedev);
 344         struct optee_supp *supp = &optee->supp;
 345         struct optee_supp_req *req;
 346         size_t n;
 347         size_t num_meta;
 348
 349         mutex_lock(&supp->mutex);
 350         req = supp_pop_req(supp, num_params, param, &num_meta);
 351         mutex_unlock(&supp->mutex);
 352
 353         if (IS_ERR(req)) {
 354                 /* Something is wrong, let supplicant restart. */
 355                 return PTR_ERR(req);
 356         }
 357
 358         /* Update out and in/out parameters */
 359         for (n = 0; n < req->num_params; n++) {
 360                 struct tee_param *p = req->param + n;
 361
 362                 switch (p->attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) {
 363                 case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
 364                 case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
 365                         p->u.value.a = param[n + num_meta].u.value.a;
 366                         p->u.value.b = param[n + num_meta].u.value.b;
 367                         p->u.value.c = param[n + num_meta].u.value.c;
 368                         break;
 369                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
 370                 case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
 371                         p->u.memref.size = param[n + num_meta].u.memref.size;
 372                         break;
 373                 default:
 374                         break;
 375                 }
 376         }
 377         req->ret = ret;
 378
 379         /* Let the requesting thread continue */
 380         complete(&req->c);
 381
 382         return 0;
 383 }