rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 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 | void optee_supp_init(struct optee_supp *supp) |
| 20 | { |
| 21 | memset(supp, 0, sizeof(*supp)); |
| 22 | mutex_init(&supp->ctx_mutex); |
| 23 | mutex_init(&supp->thrd_mutex); |
| 24 | mutex_init(&supp->supp_mutex); |
| 25 | init_completion(&supp->data_to_supp); |
| 26 | init_completion(&supp->data_from_supp); |
| 27 | } |
| 28 | |
| 29 | void optee_supp_uninit(struct optee_supp *supp) |
| 30 | { |
| 31 | mutex_destroy(&supp->ctx_mutex); |
| 32 | mutex_destroy(&supp->thrd_mutex); |
| 33 | mutex_destroy(&supp->supp_mutex); |
| 34 | } |
| 35 | |
| 36 | /** |
| 37 | * optee_supp_thrd_req() - request service from supplicant |
| 38 | * @ctx: context doing the request |
| 39 | * @func: function requested |
| 40 | * @num_params: number of elements in @param array |
| 41 | * @param: parameters for function |
| 42 | * |
| 43 | * Returns result of operation to be passed to secure world |
| 44 | */ |
| 45 | u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params, |
| 46 | struct tee_param *param) |
| 47 | { |
| 48 | bool interruptable; |
| 49 | struct optee *optee = tee_get_drvdata(ctx->teedev); |
| 50 | struct optee_supp *supp = &optee->supp; |
| 51 | u32 ret; |
| 52 | |
| 53 | /* |
| 54 | * Other threads blocks here until we've copied our answer from |
| 55 | * supplicant. |
| 56 | */ |
| 57 | while (mutex_lock_interruptible(&supp->thrd_mutex)) { |
| 58 | /* See comment below on when the RPC can be interrupted. */ |
| 59 | mutex_lock(&supp->ctx_mutex); |
| 60 | interruptable = !supp->ctx; |
| 61 | mutex_unlock(&supp->ctx_mutex); |
| 62 | if (interruptable) |
| 63 | return TEEC_ERROR_COMMUNICATION; |
| 64 | } |
| 65 | |
| 66 | /* |
| 67 | * We have exclusive access now since the supplicant at this |
| 68 | * point is either doing a |
| 69 | * wait_for_completion_interruptible(&supp->data_to_supp) or is in |
| 70 | * userspace still about to do the ioctl() to enter |
| 71 | * optee_supp_recv() below. |
| 72 | */ |
| 73 | |
| 74 | supp->func = func; |
| 75 | supp->num_params = num_params; |
| 76 | supp->param = param; |
| 77 | supp->req_posted = true; |
| 78 | |
| 79 | /* Let supplicant get the data */ |
| 80 | complete(&supp->data_to_supp); |
| 81 | |
| 82 | /* |
| 83 | * Wait for supplicant to process and return result, once we've |
| 84 | * returned from wait_for_completion(data_from_supp) we have |
| 85 | * exclusive access again. |
| 86 | */ |
| 87 | while (wait_for_completion_interruptible(&supp->data_from_supp)) { |
| 88 | mutex_lock(&supp->ctx_mutex); |
| 89 | interruptable = !supp->ctx; |
| 90 | if (interruptable) { |
| 91 | /* |
| 92 | * There's no supplicant available and since the |
| 93 | * supp->ctx_mutex currently is held none can |
| 94 | * become available until the mutex released |
| 95 | * again. |
| 96 | * |
| 97 | * Interrupting an RPC to supplicant is only |
| 98 | * allowed as a way of slightly improving the user |
| 99 | * experience in case the supplicant hasn't been |
| 100 | * started yet. During normal operation the supplicant |
| 101 | * will serve all requests in a timely manner and |
| 102 | * interrupting then wouldn't make sense. |
| 103 | */ |
| 104 | supp->ret = TEEC_ERROR_COMMUNICATION; |
| 105 | init_completion(&supp->data_to_supp); |
| 106 | } |
| 107 | mutex_unlock(&supp->ctx_mutex); |
| 108 | if (interruptable) |
| 109 | break; |
| 110 | } |
| 111 | |
| 112 | ret = supp->ret; |
| 113 | supp->param = NULL; |
| 114 | supp->req_posted = false; |
| 115 | |
| 116 | /* We're done, let someone else talk to the supplicant now. */ |
| 117 | mutex_unlock(&supp->thrd_mutex); |
| 118 | |
| 119 | return ret; |
| 120 | } |
| 121 | |
| 122 | /** |
| 123 | * optee_supp_recv() - receive request for supplicant |
| 124 | * @ctx: context receiving the request |
| 125 | * @func: requested function in supplicant |
| 126 | * @num_params: number of elements allocated in @param, updated with number |
| 127 | * used elements |
| 128 | * @param: space for parameters for @func |
| 129 | * |
| 130 | * Returns 0 on success or <0 on failure |
| 131 | */ |
| 132 | int optee_supp_recv(struct tee_context *ctx, u32 *func, u32 *num_params, |
| 133 | struct tee_param *param) |
| 134 | { |
| 135 | struct tee_device *teedev = ctx->teedev; |
| 136 | struct optee *optee = tee_get_drvdata(teedev); |
| 137 | struct optee_supp *supp = &optee->supp; |
| 138 | int rc; |
| 139 | |
| 140 | /* |
| 141 | * In case two threads in one supplicant is calling this function |
| 142 | * simultaneously we need to protect the data with a mutex which |
| 143 | * we'll release before returning. |
| 144 | */ |
| 145 | mutex_lock(&supp->supp_mutex); |
| 146 | |
| 147 | if (supp->supp_next_send) { |
| 148 | /* |
| 149 | * optee_supp_recv() has been called again without |
| 150 | * a optee_supp_send() in between. Supplicant has |
| 151 | * probably been restarted before it was able to |
| 152 | * write back last result. Abort last request and |
| 153 | * wait for a new. |
| 154 | */ |
| 155 | if (supp->req_posted) { |
| 156 | supp->ret = TEEC_ERROR_COMMUNICATION; |
| 157 | supp->supp_next_send = false; |
| 158 | complete(&supp->data_from_supp); |
| 159 | } |
| 160 | } |
| 161 | |
| 162 | /* |
| 163 | * This is where supplicant will be hanging most of the |
| 164 | * time, let's make this interruptable so we can easily |
| 165 | * restart supplicant if needed. |
| 166 | */ |
| 167 | if (wait_for_completion_interruptible(&supp->data_to_supp)) { |
| 168 | rc = -ERESTARTSYS; |
| 169 | goto out; |
| 170 | } |
| 171 | |
| 172 | /* We have exlusive access to the data */ |
| 173 | |
| 174 | if (*num_params < supp->num_params) { |
| 175 | /* |
| 176 | * Not enough room for parameters, tell supplicant |
| 177 | * it failed and abort last request. |
| 178 | */ |
| 179 | supp->ret = TEEC_ERROR_COMMUNICATION; |
| 180 | rc = -EINVAL; |
| 181 | complete(&supp->data_from_supp); |
| 182 | goto out; |
| 183 | } |
| 184 | |
| 185 | *func = supp->func; |
| 186 | *num_params = supp->num_params; |
| 187 | memcpy(param, supp->param, |
| 188 | sizeof(struct tee_param) * supp->num_params); |
| 189 | |
| 190 | /* Allow optee_supp_send() below to do its work */ |
| 191 | supp->supp_next_send = true; |
| 192 | |
| 193 | rc = 0; |
| 194 | out: |
| 195 | mutex_unlock(&supp->supp_mutex); |
| 196 | return rc; |
| 197 | } |
| 198 | |
| 199 | /** |
| 200 | * optee_supp_send() - send result of request from supplicant |
| 201 | * @ctx: context sending result |
| 202 | * @ret: return value of request |
| 203 | * @num_params: number of parameters returned |
| 204 | * @param: returned parameters |
| 205 | * |
| 206 | * Returns 0 on success or <0 on failure. |
| 207 | */ |
| 208 | int optee_supp_send(struct tee_context *ctx, u32 ret, u32 num_params, |
| 209 | struct tee_param *param) |
| 210 | { |
| 211 | struct tee_device *teedev = ctx->teedev; |
| 212 | struct optee *optee = tee_get_drvdata(teedev); |
| 213 | struct optee_supp *supp = &optee->supp; |
| 214 | size_t n; |
| 215 | int rc = 0; |
| 216 | |
| 217 | /* |
| 218 | * We still have exclusive access to the data since that's how we |
| 219 | * left it when returning from optee_supp_read(). |
| 220 | */ |
| 221 | |
| 222 | /* See comment on mutex in optee_supp_read() above */ |
| 223 | mutex_lock(&supp->supp_mutex); |
| 224 | |
| 225 | if (!supp->supp_next_send) { |
| 226 | /* |
| 227 | * Something strange is going on, supplicant shouldn't |
| 228 | * enter optee_supp_send() in this state |
| 229 | */ |
| 230 | rc = -ENOENT; |
| 231 | goto out; |
| 232 | } |
| 233 | |
| 234 | if (num_params != supp->num_params) { |
| 235 | /* |
| 236 | * Something is wrong, let supplicant restart. Next call to |
| 237 | * optee_supp_recv() will give an error to the requesting |
| 238 | * thread and release it. |
| 239 | */ |
| 240 | rc = -EINVAL; |
| 241 | goto out; |
| 242 | } |
| 243 | |
| 244 | /* Update out and in/out parameters */ |
| 245 | for (n = 0; n < num_params; n++) { |
| 246 | struct tee_param *p = supp->param + n; |
| 247 | |
| 248 | switch (p->attr) { |
| 249 | case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT: |
| 250 | case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT: |
| 251 | p->u.value.a = param[n].u.value.a; |
| 252 | p->u.value.b = param[n].u.value.b; |
| 253 | p->u.value.c = param[n].u.value.c; |
| 254 | break; |
| 255 | case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT: |
| 256 | case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT: |
| 257 | p->u.memref.size = param[n].u.memref.size; |
| 258 | break; |
| 259 | default: |
| 260 | break; |
| 261 | } |
| 262 | } |
| 263 | supp->ret = ret; |
| 264 | |
| 265 | /* Allow optee_supp_recv() above to do its work */ |
| 266 | supp->supp_next_send = false; |
| 267 | |
| 268 | /* Let the requesting thread continue */ |
| 269 | complete(&supp->data_from_supp); |
| 270 | out: |
| 271 | mutex_unlock(&supp->supp_mutex); |
| 272 | return rc; |
| 273 | } |