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306 lines
7.3 KiB
306 lines
7.3 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 2018-2019 Linaro Ltd. |
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*/ |
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#include <linux/delay.h> |
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#include <linux/of.h> |
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#include <linux/hw_random.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/tee_drv.h> |
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#include <linux/uuid.h> |
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#define DRIVER_NAME "optee-rng" |
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#define TEE_ERROR_HEALTH_TEST_FAIL 0x00000001 |
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/* |
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* TA_CMD_GET_ENTROPY - Get Entropy from RNG |
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* |
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* param[0] (inout memref) - Entropy buffer memory reference |
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* param[1] unused |
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* param[2] unused |
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* param[3] unused |
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* |
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* Result: |
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* TEE_SUCCESS - Invoke command success |
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* TEE_ERROR_BAD_PARAMETERS - Incorrect input param |
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* TEE_ERROR_NOT_SUPPORTED - Requested entropy size greater than size of pool |
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* TEE_ERROR_HEALTH_TEST_FAIL - Continuous health testing failed |
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*/ |
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#define TA_CMD_GET_ENTROPY 0x0 |
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/* |
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* TA_CMD_GET_RNG_INFO - Get RNG information |
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* |
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* param[0] (out value) - value.a: RNG data-rate in bytes per second |
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* value.b: Quality/Entropy per 1024 bit of data |
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* param[1] unused |
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* param[2] unused |
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* param[3] unused |
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* |
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* Result: |
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* TEE_SUCCESS - Invoke command success |
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* TEE_ERROR_BAD_PARAMETERS - Incorrect input param |
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*/ |
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#define TA_CMD_GET_RNG_INFO 0x1 |
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#define MAX_ENTROPY_REQ_SZ (4 * 1024) |
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/** |
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* struct optee_rng_private - OP-TEE Random Number Generator private data |
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* @dev: OP-TEE based RNG device. |
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* @ctx: OP-TEE context handler. |
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* @session_id: RNG TA session identifier. |
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* @data_rate: RNG data rate. |
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* @entropy_shm_pool: Memory pool shared with RNG device. |
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* @optee_rng: OP-TEE RNG driver structure. |
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*/ |
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struct optee_rng_private { |
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struct device *dev; |
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struct tee_context *ctx; |
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u32 session_id; |
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u32 data_rate; |
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struct tee_shm *entropy_shm_pool; |
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struct hwrng optee_rng; |
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}; |
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#define to_optee_rng_private(r) \ |
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container_of(r, struct optee_rng_private, optee_rng) |
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static size_t get_optee_rng_data(struct optee_rng_private *pvt_data, |
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void *buf, size_t req_size) |
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{ |
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int ret = 0; |
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u8 *rng_data = NULL; |
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size_t rng_size = 0; |
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struct tee_ioctl_invoke_arg inv_arg; |
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struct tee_param param[4]; |
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memset(&inv_arg, 0, sizeof(inv_arg)); |
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memset(¶m, 0, sizeof(param)); |
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/* Invoke TA_CMD_GET_ENTROPY function of Trusted App */ |
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inv_arg.func = TA_CMD_GET_ENTROPY; |
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inv_arg.session = pvt_data->session_id; |
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inv_arg.num_params = 4; |
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/* Fill invoke cmd params */ |
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param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT; |
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param[0].u.memref.shm = pvt_data->entropy_shm_pool; |
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param[0].u.memref.size = req_size; |
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param[0].u.memref.shm_offs = 0; |
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ret = tee_client_invoke_func(pvt_data->ctx, &inv_arg, param); |
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if ((ret < 0) || (inv_arg.ret != 0)) { |
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dev_err(pvt_data->dev, "TA_CMD_GET_ENTROPY invoke err: %x\n", |
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inv_arg.ret); |
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return 0; |
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} |
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rng_data = tee_shm_get_va(pvt_data->entropy_shm_pool, 0); |
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if (IS_ERR(rng_data)) { |
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dev_err(pvt_data->dev, "tee_shm_get_va failed\n"); |
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return 0; |
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} |
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rng_size = param[0].u.memref.size; |
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memcpy(buf, rng_data, rng_size); |
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return rng_size; |
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} |
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static int optee_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) |
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{ |
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struct optee_rng_private *pvt_data = to_optee_rng_private(rng); |
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size_t read = 0, rng_size = 0; |
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int timeout = 1; |
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u8 *data = buf; |
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if (max > MAX_ENTROPY_REQ_SZ) |
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max = MAX_ENTROPY_REQ_SZ; |
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while (read < max) { |
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rng_size = get_optee_rng_data(pvt_data, data, (max - read)); |
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data += rng_size; |
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read += rng_size; |
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if (wait && pvt_data->data_rate) { |
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if ((timeout-- == 0) || (read == max)) |
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return read; |
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msleep((1000 * (max - read)) / pvt_data->data_rate); |
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} else { |
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return read; |
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} |
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} |
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return read; |
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} |
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static int optee_rng_init(struct hwrng *rng) |
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{ |
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struct optee_rng_private *pvt_data = to_optee_rng_private(rng); |
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struct tee_shm *entropy_shm_pool = NULL; |
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entropy_shm_pool = tee_shm_alloc(pvt_data->ctx, MAX_ENTROPY_REQ_SZ, |
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TEE_SHM_MAPPED | TEE_SHM_DMA_BUF); |
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if (IS_ERR(entropy_shm_pool)) { |
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dev_err(pvt_data->dev, "tee_shm_alloc failed\n"); |
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return PTR_ERR(entropy_shm_pool); |
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} |
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pvt_data->entropy_shm_pool = entropy_shm_pool; |
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return 0; |
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} |
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static void optee_rng_cleanup(struct hwrng *rng) |
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{ |
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struct optee_rng_private *pvt_data = to_optee_rng_private(rng); |
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tee_shm_free(pvt_data->entropy_shm_pool); |
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} |
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static struct optee_rng_private pvt_data = { |
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.optee_rng = { |
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.name = DRIVER_NAME, |
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.init = optee_rng_init, |
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.cleanup = optee_rng_cleanup, |
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.read = optee_rng_read, |
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} |
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}; |
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static int get_optee_rng_info(struct device *dev) |
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{ |
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int ret = 0; |
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struct tee_ioctl_invoke_arg inv_arg; |
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struct tee_param param[4]; |
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memset(&inv_arg, 0, sizeof(inv_arg)); |
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memset(¶m, 0, sizeof(param)); |
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/* Invoke TA_CMD_GET_RNG_INFO function of Trusted App */ |
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inv_arg.func = TA_CMD_GET_RNG_INFO; |
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inv_arg.session = pvt_data.session_id; |
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inv_arg.num_params = 4; |
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/* Fill invoke cmd params */ |
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param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT; |
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ret = tee_client_invoke_func(pvt_data.ctx, &inv_arg, param); |
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if ((ret < 0) || (inv_arg.ret != 0)) { |
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dev_err(dev, "TA_CMD_GET_RNG_INFO invoke err: %x\n", |
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inv_arg.ret); |
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return -EINVAL; |
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} |
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pvt_data.data_rate = param[0].u.value.a; |
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pvt_data.optee_rng.quality = param[0].u.value.b; |
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return 0; |
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} |
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static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data) |
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{ |
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if (ver->impl_id == TEE_IMPL_ID_OPTEE) |
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return 1; |
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else |
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return 0; |
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} |
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static int optee_rng_probe(struct device *dev) |
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{ |
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struct tee_client_device *rng_device = to_tee_client_device(dev); |
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int ret = 0, err = -ENODEV; |
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struct tee_ioctl_open_session_arg sess_arg; |
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memset(&sess_arg, 0, sizeof(sess_arg)); |
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/* Open context with TEE driver */ |
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pvt_data.ctx = tee_client_open_context(NULL, optee_ctx_match, NULL, |
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NULL); |
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if (IS_ERR(pvt_data.ctx)) |
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return -ENODEV; |
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/* Open session with hwrng Trusted App */ |
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export_uuid(sess_arg.uuid, &rng_device->id.uuid); |
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sess_arg.clnt_login = TEE_IOCTL_LOGIN_PUBLIC; |
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sess_arg.num_params = 0; |
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ret = tee_client_open_session(pvt_data.ctx, &sess_arg, NULL); |
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if ((ret < 0) || (sess_arg.ret != 0)) { |
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dev_err(dev, "tee_client_open_session failed, err: %x\n", |
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sess_arg.ret); |
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err = -EINVAL; |
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goto out_ctx; |
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} |
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pvt_data.session_id = sess_arg.session; |
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err = get_optee_rng_info(dev); |
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if (err) |
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goto out_sess; |
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err = hwrng_register(&pvt_data.optee_rng); |
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if (err) { |
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dev_err(dev, "hwrng registration failed (%d)\n", err); |
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goto out_sess; |
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} |
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pvt_data.dev = dev; |
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return 0; |
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out_sess: |
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tee_client_close_session(pvt_data.ctx, pvt_data.session_id); |
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out_ctx: |
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tee_client_close_context(pvt_data.ctx); |
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return err; |
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} |
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static int optee_rng_remove(struct device *dev) |
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{ |
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hwrng_unregister(&pvt_data.optee_rng); |
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tee_client_close_session(pvt_data.ctx, pvt_data.session_id); |
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tee_client_close_context(pvt_data.ctx); |
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return 0; |
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} |
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static const struct tee_client_device_id optee_rng_id_table[] = { |
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{UUID_INIT(0xab7a617c, 0xb8e7, 0x4d8f, |
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0x83, 0x01, 0xd0, 0x9b, 0x61, 0x03, 0x6b, 0x64)}, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(tee, optee_rng_id_table); |
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static struct tee_client_driver optee_rng_driver = { |
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.id_table = optee_rng_id_table, |
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.driver = { |
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.name = DRIVER_NAME, |
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.bus = &tee_bus_type, |
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.probe = optee_rng_probe, |
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.remove = optee_rng_remove, |
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}, |
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}; |
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static int __init optee_rng_mod_init(void) |
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{ |
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return driver_register(&optee_rng_driver.driver); |
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} |
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static void __exit optee_rng_mod_exit(void) |
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{ |
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driver_unregister(&optee_rng_driver.driver); |
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} |
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module_init(optee_rng_mod_init); |
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module_exit(optee_rng_mod_exit); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_AUTHOR("Sumit Garg <[email protected]>"); |
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MODULE_DESCRIPTION("OP-TEE based random number generator driver");
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