// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) Microsoft Corporation * * Authors: * Thirupathaiah Annapureddy * * Description: * Device Driver for a firmware TPM as described here: * https://www.microsoft.com/en-us/research/publication/ftpm-software-implementation-tpm-chip/ * * A reference implementation is available here: * https://github.com/microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM/optee_ta/fTPM */ #include #include #include #include #include #include "tpm_tis.h" #include "tpm2_ftpm_tee.h" /** * ftpm_tee_transceive() - send fTPM commands and retrieve fTPM response. * @sendbuf - address of the data to send, byte by byte * @send_size - length of the data to send * @recvbuf - address where to read the response, byte by byte. * @recv_len - pointer to the size of buffer * * Return: * In case of success, returns 0. * On failure, -errno */ static int ftpm_tee_transceive(struct udevice *dev, const u8 *sendbuf, size_t send_size, u8 *recvbuf, size_t *recv_len) { struct ftpm_tee_private *context = dev_get_priv(dev); int rc = 0; size_t resp_len; u8 *resp_buf; struct tpm_output_header *resp_header; struct tee_invoke_arg transceive_args; struct tee_param command_params[4]; struct tee_shm *shm; if (send_size > MAX_COMMAND_SIZE) { debug("%s:send_size=%zd exceeds MAX_COMMAND_SIZE\n", __func__, send_size); return -EIO; } shm = context->shm; memset(&transceive_args, 0, sizeof(transceive_args)); memset(command_params, 0, sizeof(command_params)); /* Invoke FTPM_OPTEE_TA_SUBMIT_COMMAND function of fTPM TA */ transceive_args = (struct tee_invoke_arg) { .func = FTPM_OPTEE_TA_SUBMIT_COMMAND, .session = context->session, }; /* Fill FTPM_OPTEE_TA_SUBMIT_COMMAND parameters */ /* request */ command_params[0] = (struct tee_param) { .attr = TEE_PARAM_ATTR_TYPE_MEMREF_INPUT, .u.memref = { .shm = shm, .size = send_size, .shm_offs = 0, }, }; memset(command_params[0].u.memref.shm->addr, 0, (MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE)); memcpy(command_params[0].u.memref.shm->addr, sendbuf, send_size); /* response */ command_params[1] = (struct tee_param) { .attr = TEE_PARAM_ATTR_TYPE_MEMREF_INOUT, .u.memref = { .shm = shm, .size = MAX_RESPONSE_SIZE, .shm_offs = MAX_COMMAND_SIZE, }, }; rc = tee_invoke_func(context->tee_dev, &transceive_args, 4, command_params); if ((rc < 0) || (transceive_args.ret != 0)) { debug("%s:SUBMIT_COMMAND invoke error: 0x%x\n", __func__, transceive_args.ret); return (rc < 0) ? rc : transceive_args.ret; } resp_buf = command_params[1].u.memref.shm->addr + command_params[1].u.memref.shm_offs; resp_header = (struct tpm_output_header *)resp_buf; resp_len = be32_to_cpu(resp_header->length); /* sanity check resp_len*/ if (resp_len < TPM_HEADER_SIZE) { debug("%s:tpm response header too small\n", __func__); return -EIO; } if (resp_len > MAX_RESPONSE_SIZE) { debug("%s:resp_len=%zd exceeds MAX_RESPONSE_SIZE\n", __func__, resp_len); return -EIO; } if (resp_len > *recv_len) { debug("%s:response length is bigger than receive buffer\n", __func__); return -EIO; } /* sanity checks look good, copy the response */ memcpy(recvbuf, resp_buf, resp_len); *recv_len = resp_len; return 0; } static int ftpm_tee_open(struct udevice *dev) { struct ftpm_tee_private *context = dev_get_priv(dev); if (context->is_open) return -EBUSY; context->is_open = 1; return 0; } static int ftpm_tee_close(struct udevice *dev) { struct ftpm_tee_private *context = dev_get_priv(dev); if (context->is_open) context->is_open = 0; return 0; } static int ftpm_tee_desc(struct udevice *dev, char *buf, int size) { if (size < 32) return -ENOSPC; return snprintf(buf, size, "Microsoft OP-TEE fTPM"); } static int ftpm_tee_match(struct tee_version_data *vers, const void *data) { debug("%s:vers->gen_caps =0x%x\n", __func__, vers->gen_caps); /* * Currently this driver only support GP Complaint OPTEE based fTPM TA */ return vers->gen_caps & TEE_GEN_CAP_GP; } static int ftpm_tee_probe(struct udevice *dev) { int rc; struct tpm_chip_priv *priv = dev_get_uclass_priv(dev); struct ftpm_tee_private *context = dev_get_priv(dev); struct tee_open_session_arg sess_arg; const struct tee_optee_ta_uuid uuid = TA_FTPM_UUID; memset(context, 0, sizeof(*context)); /* Use the TPM v2 stack */ priv->version = TPM_V2; priv->pcr_count = 24; priv->pcr_select_min = 3; /* Find TEE device */ context->tee_dev = tee_find_device(NULL, ftpm_tee_match, NULL, NULL); if (!context->tee_dev) { debug("%s:tee_find_device failed\n", __func__); return -ENODEV; } /* Open a session with the fTPM TA */ memset(&sess_arg, 0, sizeof(sess_arg)); sess_arg.clnt_login = TEE_LOGIN_REE_KERNEL; tee_optee_ta_uuid_to_octets(sess_arg.uuid, &uuid); rc = tee_open_session(context->tee_dev, &sess_arg, 0, NULL); if ((rc < 0) || (sess_arg.ret != 0)) { debug("%s:tee_open_session failed, err=%x\n", __func__, sess_arg.ret); return -EIO; } context->session = sess_arg.session; /* Allocate dynamic shared memory with fTPM TA */ rc = tee_shm_alloc(context->tee_dev, MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE, 0, &context->shm); if (rc) { debug("%s:tee_shm_alloc failed with rc = %d\n", __func__, rc); goto out_shm_alloc; } return 0; out_shm_alloc: tee_close_session(context->tee_dev, context->session); return rc; } static int ftpm_tee_remove(struct udevice *dev) { struct ftpm_tee_private *context = dev_get_priv(dev); int rc; /* tee_pre_remove frees any leftover TEE shared memory */ /* close the existing session with fTPM TA*/ rc = tee_close_session(context->tee_dev, context->session); debug("%s: tee_close_session - rc =%d\n", __func__, rc); return 0; } static const struct tpm_ops ftpm_tee_ops = { .open = ftpm_tee_open, .close = ftpm_tee_close, .get_desc = ftpm_tee_desc, .xfer = ftpm_tee_transceive, }; static const struct udevice_id ftpm_tee_ids[] = { { .compatible = "microsoft,ftpm" }, { } }; U_BOOT_DRIVER(ftpm_tee) = { .name = "ftpm_tee", .id = UCLASS_TPM, .of_match = ftpm_tee_ids, .ops = &ftpm_tee_ops, .probe = ftpm_tee_probe, .remove = ftpm_tee_remove, .flags = DM_FLAG_OS_PREPARE, .priv_auto = sizeof(struct ftpm_tee_private), };