[RFC PATCH] tee: tstee: Add initial Trusted Services TEE driver
Sumit Garg
sumit.garg at linaro.org
Tue Oct 3 08:42:13 PDT 2023
Hi Balint,
Thanks for your effort to put up this driver. It's interesting to see
how the TEE subsystem can be utilized to address different use-cases.
On Wed, 27 Sept 2023 at 20:56, Balint Dobszay <balint.dobszay at arm.com> wrote:
>
> The Trusted Services project provides a framework for developing and
> deploying device Root Of Trust services in FF-A Secure Partitions. The
> FF-A SPs are accessible through the FF-A driver, but this doesn't
> provide a user space interface. The goal of this TEE driver is to make
> Trusted Services SPs accessible for user space clients.
I am interested in exploring the user space library/applications. Do
you have a standard library implementation and some example user-space
applications leveraging this driver interface?
>
> All TS SPs have the same FF-A UUID, it identifies the RPC protocol used
> by TS. A TS SP can host one or more services, a service is identified by
> its service UUID. The same type of service cannot be present twice in
> the same SP. During SP boot each service in the SP gets assigned an
> interface ID, this is just a short ID to simplify message addressing.
> There is 1:1 mapping between TS SPs and TEE devices, i.e. a TEE device
> gets registered for each Trusted Services compatible FF-A device found
> on the FF-A bus. Opening the SP corresponds to opening the TEE dev and
> creating a TEE context. A TS SP hosts one or more services, opening a
> service corresponds to opening a session in the given tee_context.
>
> Signed-off-by: Balint Dobszay <balint.dobszay at arm.com>
> ---
>
> Hi All,
>
> This is an initial TEE driver implementation for Trusted Services [1].
> Trusted Services is a TrustedFirmware.org project that provides a
> framework for developing and deploying device Root Of Trust services in
> FF-A Secure Partitions. The project hosts the reference implementation
> of Arm Platform Security Architecture [2] for Arm A-profile devices.
>
> The FF-A Secure Partitions (SPs) are accessible through the FF-A driver
> in Linux. However, the FF-A driver doesn't have a user space interface
> so user space clients currently cannot access Trusted Services. The goal
> of this TEE driver is to bridge this gap and make Trusted Services
> functionality accessible from user space.
>
> The predecessor of this driver is an out-of-tree kernel module that we
> have been using for prototyping [3]. An integration of Trusted Services,
> OP-TEE as a S-EL1 SPMC, TF-A, Linux and this out-of-tree module is
> available as part of the OP-TEE project, please find the manifest file
> at [4].
>
> Some key points about the structure of Trusted Services (for more
> details please see the documentation at [5]):
> - A Trusted Services SP can host one or multiple services. All TS SPs
> have the same FF-A UUID, it identifies the RPC protocol used by TS.
> The protocol's register ABI definition is available at [6] and is
> implemented in tstee_private.h.
> - A service hosted by an SP is identified by its service UUID. The
> same type of service can be present in multiple SPs, but not twice in
> the same SP. During SP boot each service in the SP gets assigned an
> interface ID, this is just a short ID to simplify message addressing.
> - There is 1:1 mapping between TS SPs and TEE devices, i.e. a TEE device
> gets registered for each Trusted Services compatible FF-A device found
> on the FF-A bus.
> - Opening the SP corresponds to opening the TEE dev and creating a TEE
> context. A TS SP hosts one or more services, opening a service
> corresponds to opening a session in the given tee_context.
>
> Regards,
> Balint
>
> [1] https://www.trustedfirmware.org/projects/trusted-services/
> [2] https://www.arm.com/architecture/security-features/platform-security
> [3] https://gitlab.arm.com/linux-arm/linux-trusted-services
> [4] https://github.com/OP-TEE/manifest/blob/master/fvp-ts.xml
> [5] https://trusted-services.readthedocs.io
> [6] https://trusted-services.readthedocs.io/en/integration/developer/service-access-protocols.html#abi
>
> drivers/tee/Kconfig | 1 +
> drivers/tee/Makefile | 1 +
> drivers/tee/tstee/Kconfig | 11 +
> drivers/tee/tstee/Makefile | 3 +
> drivers/tee/tstee/core.c | 473 ++++++++++++++++++++++++++++++
> drivers/tee/tstee/shm_pool.c | 91 ++++++
> drivers/tee/tstee/tstee_private.h | 97 ++++++
> include/uapi/linux/tee.h | 1 +
> 8 files changed, 678 insertions(+)
> create mode 100644 drivers/tee/tstee/Kconfig
> create mode 100644 drivers/tee/tstee/Makefile
> create mode 100644 drivers/tee/tstee/core.c
> create mode 100644 drivers/tee/tstee/shm_pool.c
> create mode 100644 drivers/tee/tstee/tstee_private.h
>
> diff --git a/drivers/tee/Kconfig b/drivers/tee/Kconfig
> index 73a147202e88..61b507c18780 100644
> --- a/drivers/tee/Kconfig
> +++ b/drivers/tee/Kconfig
> @@ -15,5 +15,6 @@ if TEE
>
> source "drivers/tee/optee/Kconfig"
> source "drivers/tee/amdtee/Kconfig"
> +source "drivers/tee/tstee/Kconfig"
>
> endif
> diff --git a/drivers/tee/Makefile b/drivers/tee/Makefile
> index 68da044afbfa..5488cba30bd2 100644
> --- a/drivers/tee/Makefile
> +++ b/drivers/tee/Makefile
> @@ -5,3 +5,4 @@ tee-objs += tee_shm.o
> tee-objs += tee_shm_pool.o
> obj-$(CONFIG_OPTEE) += optee/
> obj-$(CONFIG_AMDTEE) += amdtee/
> +obj-$(CONFIG_ARM_TSTEE) += tstee/
> diff --git a/drivers/tee/tstee/Kconfig b/drivers/tee/tstee/Kconfig
> new file mode 100644
> index 000000000000..cd8d32586a77
> --- /dev/null
> +++ b/drivers/tee/tstee/Kconfig
> @@ -0,0 +1,11 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +config ARM_TSTEE
> + tristate "Arm Trusted Services TEE driver"
> + depends on ARM_FFA_TRANSPORT
> + default n
> + help
> + The Trusted Services project provides a framework for developing and
> + deploying device Root Of Trust services in FF-A Secure Partitions.
> + This driver provides an interface to make Trusted Services Secure
> + Partitions accessible for user space clients, since the FF-A driver
> + doesn't implement a user space interface directly.
> diff --git a/drivers/tee/tstee/Makefile b/drivers/tee/tstee/Makefile
> new file mode 100644
> index 000000000000..dd54b1f88652
> --- /dev/null
> +++ b/drivers/tee/tstee/Makefile
> @@ -0,0 +1,3 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +arm-tstee-objs := core.o shm_pool.o
> +obj-$(CONFIG_ARM_TSTEE) = arm-tstee.o
> diff --git a/drivers/tee/tstee/core.c b/drivers/tee/tstee/core.c
> new file mode 100644
> index 000000000000..c0194638b7da
> --- /dev/null
> +++ b/drivers/tee/tstee/core.c
> @@ -0,0 +1,473 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2023, Arm Limited
> + */
> +
> +#define DRIVER_NAME "Arm TSTEE"
> +#define pr_fmt(fmt) DRIVER_NAME ": " fmt
> +
> +#include <linux/arm_ffa.h>
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +#include <linux/kernel.h>
> +#include <linux/limits.h>
> +#include <linux/list.h>
> +#include <linux/mm.h>
> +#include <linux/module.h>
> +#include <linux/scatterlist.h>
> +#include <linux/slab.h>
> +#include <linux/stat.h>
> +#include <linux/tee_drv.h>
> +#include <linux/types.h>
> +#include <linux/uaccess.h>
> +
> +#include "tstee_private.h"
> +
> +#define FFA_INVALID_MEM_HANDLE U64_MAX
> +
> +static void arg_list_to_ffa_data(const u32 *args, struct ffa_send_direct_data *data)
> +{
> + data->data0 = args[0];
> + data->data1 = args[1];
> + data->data2 = args[2];
> + data->data3 = args[3];
> + data->data4 = args[4];
> +}
> +
> +static void arg_list_from_ffa_data(const struct ffa_send_direct_data *data, u32 *args)
> +{
> + args[0] = lower_32_bits(data->data0);
> + args[1] = lower_32_bits(data->data1);
> + args[2] = lower_32_bits(data->data2);
> + args[3] = lower_32_bits(data->data3);
> + args[4] = lower_32_bits(data->data4);
> +}
> +
> +static void tstee_get_version(struct tee_device *teedev, struct tee_ioctl_version_data *vers)
> +{
> + struct tstee *tstee = tee_get_drvdata(teedev);
> + struct tee_ioctl_version_data v = {
> + .impl_id = TEE_IMPL_ID_TSTEE,
> + .impl_caps = tstee->ffa_dev->vm_id,
> + .gen_caps = 0,
> + };
> +
> + *vers = v;
> +}
> +
> +static int tstee_open(struct tee_context *ctx)
> +{
> + struct ts_context_data *ctxdata;
> +
> + ctxdata = kzalloc(sizeof(*ctxdata), GFP_KERNEL);
> + if (!ctxdata)
> + return -ENOMEM;
> +
> + mutex_init(&ctxdata->mutex);
> + idr_init(&ctxdata->sess_ids);
> + INIT_LIST_HEAD(&ctxdata->sess_list);
> +
> + ctx->data = ctxdata;
> +
> + return 0;
> +}
> +
> +static void tstee_release(struct tee_context *ctx)
> +{
> + struct ts_context_data *ctxdata = ctx->data;
> + struct ts_session *sess, *sess_tmp;
> +
> + if (!ctxdata)
> + return;
> +
> + list_for_each_entry_safe(sess, sess_tmp, &ctxdata->sess_list, list_node) {
> + list_del(&sess->list_node);
> + idr_remove(&ctxdata->sess_ids, sess->session_id);
> + kfree(sess);
> + }
> +
> + idr_destroy(&ctxdata->sess_ids);
> + mutex_destroy(&ctxdata->mutex);
> +
> + kfree(ctxdata);
> + ctx->data = NULL;
> +}
> +
> +static struct ts_session *find_session(struct ts_context_data *ctxdata, u32 session_id)
> +{
> + struct ts_session *sess;
> +
> + list_for_each_entry(sess, &ctxdata->sess_list, list_node)
> + if (sess->session_id == session_id)
> + return sess;
> +
> + return NULL;
> +}
> +
> +static int tstee_open_session(struct tee_context *ctx, struct tee_ioctl_open_session_arg *arg,
> + struct tee_param *param __always_unused)
> +{
> + struct tstee *tstee = tee_get_drvdata(ctx->teedev);
> + struct ffa_device *ffa_dev = tstee->ffa_dev;
> + struct ts_context_data *ctxdata = ctx->data;
> + struct ffa_send_direct_data ffa_data;
> + struct ts_session *sess = NULL;
> + u32 ffa_args[5] = {};
> + int sess_id;
> + int rc;
> +
> + ffa_args[TS_RPC_CTRL_REG] = TS_RPC_CTRL_PACK_IFACE_OPCODE(TS_RPC_MGMT_IFACE_ID,
> + TS_RPC_OP_SERVICE_INFO);
> +
> + memcpy((u8 *)(ffa_args + TS_RPC_SERVICE_INFO_UUID0), arg->uuid, UUID_SIZE);
> +
> + arg_list_to_ffa_data(ffa_args, &ffa_data);
> + rc = ffa_dev->ops->msg_ops->sync_send_receive(ffa_dev, &ffa_data);
> + if (rc)
> + return rc;
> +
> + arg_list_from_ffa_data(&ffa_data, ffa_args);
> +
> + if (ffa_args[TS_RPC_SERVICE_INFO_RPC_STATUS] != TS_RPC_OK)
> + return -ENODEV;
> +
> + if (ffa_args[TS_RPC_SERVICE_INFO_IFACE] > U8_MAX)
> + return -EINVAL;
> +
> + sess = kzalloc(sizeof(*sess), GFP_KERNEL);
> + if (!sess)
> + return -ENOMEM;
> +
> + sess_id = idr_alloc(&ctxdata->sess_ids, sess, 1, 0, GFP_KERNEL);
> + if (sess_id < 0) {
> + kfree(sess);
> + return sess_id;
> + }
> +
> + sess->session_id = sess_id;
> + sess->iface_id = ffa_args[TS_RPC_SERVICE_INFO_IFACE];
> +
> + mutex_lock(&ctxdata->mutex);
> + list_add(&sess->list_node, &ctxdata->sess_list);
> + mutex_unlock(&ctxdata->mutex);
> +
> + arg->session = sess_id;
> + arg->ret = 0;
> +
> + return 0;
> +}
> +
> +static int tstee_close_session(struct tee_context *ctx, u32 session)
> +{
> + struct ts_context_data *ctxdata = ctx->data;
> + struct ts_session *sess;
> +
> + mutex_lock(&ctxdata->mutex);
> + sess = find_session(ctxdata, session);
> + if (sess)
> + list_del(&sess->list_node);
> +
> + mutex_unlock(&ctxdata->mutex);
> +
> + if (!sess)
> + return -EINVAL;
> +
> + idr_remove(&ctxdata->sess_ids, sess->session_id);
> + kfree(sess);
> +
> + return 0;
> +}
> +
> +static int tstee_invoke_func(struct tee_context *ctx, struct tee_ioctl_invoke_arg *arg,
> + struct tee_param *param)
> +{
> + struct tstee *tstee = tee_get_drvdata(ctx->teedev);
> + struct ffa_device *ffa_dev = tstee->ffa_dev;
> + struct ts_context_data *ctxdata = ctx->data;
> + struct ffa_send_direct_data ffa_data;
> + struct tee_shm *shm = NULL;
> + struct ts_session *sess;
> + u32 req_len, ffa_args[5] = {};
> + int shm_id, rc;
> + u8 iface_id;
> + u64 handle;
> + u16 opcode;
> +
> + mutex_lock(&ctxdata->mutex);
> + sess = find_session(ctxdata, arg->session);
> +
> + /* Do this while holding the mutex to make sure that the session wasn't closed meanwhile */
> + if (sess)
> + iface_id = sess->iface_id;
> +
> + mutex_unlock(&ctxdata->mutex);
> + if (!sess)
> + return -EINVAL;
> +
> + opcode = lower_16_bits(arg->func);
> + shm_id = lower_32_bits(param[0].u.value.a);
> + req_len = lower_32_bits(param[0].u.value.b);
> +
> + if (shm_id != 0) {
> + shm = tee_shm_get_from_id(ctx, shm_id);
> + if (IS_ERR(shm))
> + return PTR_ERR(shm);
> +
> + if (shm->size < req_len) {
> + pr_err("request doesn't fit into shared memory buffer\n");
> + rc = -EINVAL;
> + goto out;
> + }
> +
> + handle = shm->sec_world_id;
> + } else {
> + handle = FFA_INVALID_MEM_HANDLE;
> + }
> +
> + ffa_args[TS_RPC_CTRL_REG] = TS_RPC_CTRL_PACK_IFACE_OPCODE(iface_id, opcode);
> + ffa_args[TS_RPC_SERVICE_MEM_HANDLE_LSW] = lower_32_bits(handle);
> + ffa_args[TS_RPC_SERVICE_MEM_HANDLE_MSW] = upper_32_bits(handle);
> + ffa_args[TS_RPC_SERVICE_REQ_LEN] = req_len;
> + ffa_args[TS_RPC_SERVICE_CLIENT_ID] = 0;
> +
> + arg_list_to_ffa_data(ffa_args, &ffa_data);
> + rc = ffa_dev->ops->msg_ops->sync_send_receive(ffa_dev, &ffa_data);
I haven't dug deeper into the ABI yet, which is something I will look
into. But these RPC commands caught my attention. Are these RPC calls
blocking in nature? Is there a possibility that these could cause CPU
stalls? Do the Linux interrupts remain unhandled until the RPC calls
return?
-Sumit
> + if (rc)
> + goto out;
> +
> + arg_list_from_ffa_data(&ffa_data, ffa_args);
> +
> + if (ffa_args[TS_RPC_SERVICE_RPC_STATUS] != TS_RPC_OK) {
> + pr_err("invoke_func rpc status: %d\n", ffa_args[TS_RPC_SERVICE_RPC_STATUS]);
> + rc = -EINVAL;
> + goto out;
> + }
> +
> + arg->ret = ffa_args[TS_RPC_SERVICE_STATUS];
> + if (shm && shm->size >= ffa_args[TS_RPC_SERVICE_RESP_LEN])
> + param[0].u.value.a = ffa_args[TS_RPC_SERVICE_RESP_LEN];
> +
> +out:
> + if (shm)
> + tee_shm_put(shm);
> +
> + return rc;
> +}
> +
> +static int tstee_cancel_req(struct tee_context *ctx __always_unused, u32 cancel_id __always_unused,
> + u32 session __always_unused)
> +{
> + return -EINVAL;
> +}
> +
> +int tstee_shm_register(struct tee_context *ctx, struct tee_shm *shm, struct page **pages,
> + size_t num_pages, unsigned long start __always_unused)
> +{
> + struct tstee *tstee = tee_get_drvdata(ctx->teedev);
> + struct ffa_device *ffa_dev = tstee->ffa_dev;
> + struct ffa_mem_region_attributes mem_attr = {
> + .receiver = tstee->ffa_dev->vm_id,
> + .attrs = FFA_MEM_RW,
> + .flag = 0,
> + };
> + struct ffa_mem_ops_args mem_args = {
> + .attrs = &mem_attr,
> + .use_txbuf = true,
> + .nattrs = 1,
> + .flags = 0,
> + };
> + struct ffa_send_direct_data ffa_data;
> + struct sg_table sgt;
> + u32 ffa_args[5] = {};
> + int rc;
> +
> + rc = sg_alloc_table_from_pages(&sgt, pages, num_pages, 0, num_pages * PAGE_SIZE,
> + GFP_KERNEL);
> + if (rc)
> + return rc;
> +
> + mem_args.sg = sgt.sgl;
> + rc = ffa_dev->ops->mem_ops->memory_share(&mem_args);
> + sg_free_table(&sgt);
> + if (rc)
> + return rc;
> +
> + shm->sec_world_id = mem_args.g_handle;
> +
> + ffa_args[TS_RPC_CTRL_REG] = TS_RPC_CTRL_PACK_IFACE_OPCODE(TS_RPC_MGMT_IFACE_ID,
> + TS_RPC_OP_RETRIEVE_MEM);
> + ffa_args[TS_RPC_RETRIEVE_MEM_HANDLE_LSW] = lower_32_bits(shm->sec_world_id);
> + ffa_args[TS_RPC_RETRIEVE_MEM_HANDLE_MSW] = upper_32_bits(shm->sec_world_id);
> + ffa_args[TS_RPC_RETRIEVE_MEM_TAG_LSW] = 0;
> + ffa_args[TS_RPC_RETRIEVE_MEM_TAG_MSW] = 0;
> +
> + arg_list_to_ffa_data(ffa_args, &ffa_data);
> + rc = ffa_dev->ops->msg_ops->sync_send_receive(ffa_dev, &ffa_data);
> + if (rc) {
> + (void)ffa_dev->ops->mem_ops->memory_reclaim(shm->sec_world_id, 0);
> + return rc;
> + }
> +
> + arg_list_from_ffa_data(&ffa_data, ffa_args);
> +
> + if (ffa_args[TS_RPC_RETRIEVE_MEM_RPC_STATUS] != TS_RPC_OK) {
> + pr_err("shm_register rpc status: %d\n", ffa_args[TS_RPC_RETRIEVE_MEM_RPC_STATUS]);
> + ffa_dev->ops->mem_ops->memory_reclaim(shm->sec_world_id, 0);
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +int tstee_shm_unregister(struct tee_context *ctx, struct tee_shm *shm)
> +{
> + struct tstee *tstee = tee_get_drvdata(ctx->teedev);
> + struct ffa_device *ffa_dev = tstee->ffa_dev;
> + struct ffa_send_direct_data ffa_data;
> + u32 ffa_args[5] = {};
> + int rc;
> +
> + ffa_args[TS_RPC_CTRL_REG] = TS_RPC_CTRL_PACK_IFACE_OPCODE(TS_RPC_MGMT_IFACE_ID,
> + TS_RPC_OP_RELINQ_MEM);
> + ffa_args[TS_RPC_RELINQ_MEM_HANDLE_LSW] = lower_32_bits(shm->sec_world_id);
> + ffa_args[TS_RPC_RELINQ_MEM_HANDLE_MSW] = upper_32_bits(shm->sec_world_id);
> +
> + arg_list_to_ffa_data(ffa_args, &ffa_data);
> + rc = ffa_dev->ops->msg_ops->sync_send_receive(ffa_dev, &ffa_data);
> + if (rc)
> + return rc;
> + arg_list_from_ffa_data(&ffa_data, ffa_args);
> +
> + if (ffa_args[TS_RPC_RELINQ_MEM_RPC_STATUS] != TS_RPC_OK) {
> + pr_err("shm_unregister rpc status: %d\n", ffa_args[TS_RPC_RELINQ_MEM_RPC_STATUS]);
> + return -EINVAL;
> + }
> +
> + rc = ffa_dev->ops->mem_ops->memory_reclaim(shm->sec_world_id, 0);
> +
> + return rc;
> +}
> +
> +static const struct tee_driver_ops tstee_ops = {
> + .get_version = tstee_get_version,
> + .open = tstee_open,
> + .release = tstee_release,
> + .open_session = tstee_open_session,
> + .close_session = tstee_close_session,
> + .invoke_func = tstee_invoke_func,
> + .cancel_req = tstee_cancel_req,
> + .shm_register = tstee_shm_register,
> + .shm_unregister = tstee_shm_unregister,
> +};
> +
> +static const struct tee_desc tstee_desc = {
> + .name = "tstee-clnt",
> + .ops = &tstee_ops,
> + .owner = THIS_MODULE,
> +};
> +
> +static bool tstee_check_rpc_compatible(struct ffa_device *ffa_dev)
> +{
> + struct ffa_send_direct_data ffa_data;
> + u32 ffa_args[5] = {};
> +
> + ffa_args[TS_RPC_CTRL_REG] = TS_RPC_CTRL_PACK_IFACE_OPCODE(TS_RPC_MGMT_IFACE_ID,
> + TS_RPC_OP_GET_VERSION);
> +
> + arg_list_to_ffa_data(ffa_args, &ffa_data);
> + if (ffa_dev->ops->msg_ops->sync_send_receive(ffa_dev, &ffa_data))
> + return false;
> +
> + arg_list_from_ffa_data(&ffa_data, ffa_args);
> +
> + return ffa_args[TS_RPC_GET_VERSION_RESP] == TS_RPC_PROTOCOL_VERSION;
> +}
> +
> +static void tstee_deinit_common(struct tstee *tstee)
> +{
> + tee_device_unregister(tstee->teedev);
> + if (tstee->pool)
> + tee_shm_pool_free(tstee->pool);
> +
> + kfree(tstee);
> +}
> +
> +static int tstee_probe(struct ffa_device *ffa_dev)
> +{
> + struct tstee *tstee;
> + int rc;
> +
> + ffa_dev->ops->msg_ops->mode_32bit_set(ffa_dev);
> +
> + if (!tstee_check_rpc_compatible(ffa_dev))
> + return -EINVAL;
> +
> + tstee = kzalloc(sizeof(*tstee), GFP_KERNEL);
> + if (!tstee)
> + return -ENOMEM;
> +
> + tstee->ffa_dev = ffa_dev;
> +
> + tstee->pool = tstee_create_shm_pool();
> + if (IS_ERR(tstee->pool)) {
> + rc = PTR_ERR(tstee->pool);
> + tstee->pool = NULL;
> + goto err;
> + }
> +
> + tstee->teedev = tee_device_alloc(&tstee_desc, NULL, tstee->pool, tstee);
> + if (IS_ERR(tstee->teedev)) {
> + rc = PTR_ERR(tstee->teedev);
> + tstee->teedev = NULL;
> + goto err;
> + }
> +
> + rc = tee_device_register(tstee->teedev);
> + if (rc)
> + goto err;
> +
> + ffa_dev_set_drvdata(ffa_dev, tstee);
> +
> + pr_info("driver initialized for endpoint 0x%x\n", ffa_dev->vm_id);
> +
> + return 0;
> +
> +err:
> + tstee_deinit_common(tstee);
> + return rc;
> +}
> +
> +static void tstee_remove(struct ffa_device *ffa_dev)
> +{
> + tstee_deinit_common(ffa_dev->dev.driver_data);
> +}
> +
> +static const struct ffa_device_id tstee_device_ids[] = {
> + /* TS RPC protocol UUID: bdcd76d7-825e-4751-963b-86d4f84943ac */
> + { TS_RPC_UUID },
> + {}
> +};
> +
> +static struct ffa_driver tstee_driver = {
> + .name = "arm_tstee",
> + .probe = tstee_probe,
> + .remove = tstee_remove,
> + .id_table = tstee_device_ids,
> +};
> +
> +static int __init mod_init(void)
> +{
> + return ffa_register(&tstee_driver);
> +}
> +module_init(mod_init)
> +
> +static void __exit mod_exit(void)
> +{
> + ffa_unregister(&tstee_driver);
> +}
> +module_exit(mod_exit)
> +
> +MODULE_ALIAS("arm-tstee");
> +MODULE_AUTHOR("Balint Dobszay <balint.dobszay at arm.com>");
> +MODULE_DESCRIPTION("Arm Trusted Services TEE driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/tee/tstee/shm_pool.c b/drivers/tee/tstee/shm_pool.c
> new file mode 100644
> index 000000000000..518c10dd0735
> --- /dev/null
> +++ b/drivers/tee/tstee/shm_pool.c
> @@ -0,0 +1,91 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2023, Arm Limited
> + */
> +
> +#include <linux/arm_ffa.h>
> +#include <linux/device.h>
> +#include <linux/dma-buf.h>
> +#include <linux/genalloc.h>
> +#include <linux/slab.h>
> +#include <linux/tee_drv.h>
> +
> +#include "tstee_private.h"
> +
> +static int pool_op_alloc(struct tee_shm_pool *pool __always_unused, struct tee_shm *shm,
> + size_t size, size_t align __always_unused)
> +{
> + unsigned int order, nr_pages, i;
> + struct page *page, **pages;
> + int rc;
> +
> + if (size == 0)
> + return -EINVAL;
> +
> + order = get_order(size);
> + nr_pages = 1 << order;
> +
> + page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
> + if (!page)
> + return -ENOMEM;
> +
> + shm->kaddr = page_address(page);
> + shm->paddr = page_to_phys(page);
> + shm->size = PAGE_SIZE << order;
> +
> + pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL);
> + if (!pages) {
> + rc = -ENOMEM;
> + goto err;
> + }
> +
> + for (i = 0; i < nr_pages; i++)
> + pages[i] = page + i;
> +
> + rc = tstee_shm_register(shm->ctx, shm, pages, nr_pages, (unsigned long)shm->kaddr);
> + kfree(pages);
> + if (rc)
> + goto err;
> +
> + return 0;
> +
> +err:
> + __free_pages(page, order);
> + return rc;
> +}
> +
> +static void pool_op_free(struct tee_shm_pool *pool __always_unused, struct tee_shm *shm)
> +{
> + int rc;
> +
> + rc = tstee_shm_unregister(shm->ctx, shm);
> + if (rc)
> + pr_err("shm id 0x%llx unregister rc %d\n", shm->sec_world_id, rc);
> +
> + free_pages((unsigned long)shm->kaddr, get_order(shm->size));
> + shm->kaddr = NULL;
> +}
> +
> +static void pool_op_destroy_pool(struct tee_shm_pool *pool)
> +{
> + kfree(pool);
> +}
> +
> +static const struct tee_shm_pool_ops pool_ops = {
> + .alloc = pool_op_alloc,
> + .free = pool_op_free,
> + .destroy_pool = pool_op_destroy_pool,
> +};
> +
> +struct tee_shm_pool *tstee_create_shm_pool(void)
> +{
> + struct tee_shm_pool *pool;
> +
> + pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> + if (!pool)
> + return ERR_PTR(-ENOMEM);
> +
> + pool->ops = &pool_ops;
> +
> + return pool;
> +}
> diff --git a/drivers/tee/tstee/tstee_private.h b/drivers/tee/tstee/tstee_private.h
> new file mode 100644
> index 000000000000..2ea266804ccf
> --- /dev/null
> +++ b/drivers/tee/tstee/tstee_private.h
> @@ -0,0 +1,97 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2023, Arm Limited
> + */
> +
> +#ifndef TSTEE_PRIVATE_H
> +#define TSTEE_PRIVATE_H
> +
> +#include <linux/arm_ffa.h>
> +#include <linux/bitops.h>
> +#include <linux/idr.h>
> +#include <linux/tee_drv.h>
> +#include <linux/types.h>
> +#include <linux/uuid.h>
> +
> +/* UUID of this protocol */
> +#define TS_RPC_UUID UUID_INIT(0xbdcd76d7, 0x825e, 0x4751, \
> + 0x96, 0x3b, 0x86, 0xd4, 0xf8, 0x49, 0x43, 0xac)
> +
> +/* Protocol version*/
> +#define TS_RPC_PROTOCOL_VERSION (1)
> +
> +/* Status codes */
> +#define TS_RPC_OK (0)
> +
> +/* RPC control register */
> +#define TS_RPC_CTRL_REG (0)
> +#define OPCODE_MASK GENMASK(15, 0)
> +#define IFACE_ID_MASK GENMASK(23, 16)
> +#define TS_RPC_CTRL_OPCODE(x) ((u16)(FIELD_GET(OPCODE_MASK, (x))))
> +#define TS_RPC_CTRL_IFACE_ID(x) ((u8)(FIELD_GET(IFACE_ID_MASK, (x))))
> +#define TS_RPC_CTRL_PACK_IFACE_OPCODE(i, o) \
> + (FIELD_PREP(IFACE_ID_MASK, (i)) | FIELD_PREP(OPCODE_MASK, (o)))
> +#define TS_RPC_CTRL_SAP_RC BIT(30)
> +#define TS_RPC_CTRL_SAP_ERR BIT(31)
> +
> +/* Interface ID for RPC management operations */
> +#define TS_RPC_MGMT_IFACE_ID (0xff)
> +
> +/* Management calls */
> +#define TS_RPC_OP_GET_VERSION (0x0000)
> +#define TS_RPC_GET_VERSION_RESP (1)
> +
> +#define TS_RPC_OP_RETRIEVE_MEM (0x0001)
> +#define TS_RPC_RETRIEVE_MEM_HANDLE_LSW (1)
> +#define TS_RPC_RETRIEVE_MEM_HANDLE_MSW (2)
> +#define TS_RPC_RETRIEVE_MEM_TAG_LSW (3)
> +#define TS_RPC_RETRIEVE_MEM_TAG_MSW (4)
> +#define TS_RPC_RETRIEVE_MEM_RPC_STATUS (1)
> +
> +#define TS_RPC_OP_RELINQ_MEM (0x0002)
> +#define TS_RPC_RELINQ_MEM_HANDLE_LSW (1)
> +#define TS_RPC_RELINQ_MEM_HANDLE_MSW (2)
> +#define TS_RPC_RELINQ_MEM_RPC_STATUS (1)
> +
> +#define TS_RPC_OP_SERVICE_INFO (0x0003)
> +#define TS_RPC_SERVICE_INFO_UUID0 (1)
> +#define TS_RPC_SERVICE_INFO_UUID1 (2)
> +#define TS_RPC_SERVICE_INFO_UUID2 (3)
> +#define TS_RPC_SERVICE_INFO_UUID3 (4)
> +#define TS_RPC_SERVICE_INFO_RPC_STATUS (1)
> +#define TS_RPC_SERVICE_INFO_IFACE (2)
> +
> +/* Service call */
> +#define TS_RPC_SERVICE_MEM_HANDLE_LSW (1)
> +#define TS_RPC_SERVICE_MEM_HANDLE_MSW (2)
> +#define TS_RPC_SERVICE_REQ_LEN (3)
> +#define TS_RPC_SERVICE_CLIENT_ID (4)
> +#define TS_RPC_SERVICE_RPC_STATUS (1)
> +#define TS_RPC_SERVICE_STATUS (2)
> +#define TS_RPC_SERVICE_RESP_LEN (3)
> +
> +struct tstee {
> + struct ffa_device *ffa_dev;
> + struct tee_device *teedev;
> + struct tee_shm_pool *pool;
> +};
> +
> +struct ts_session {
> + struct list_head list_node;
> + u32 session_id;
> + u8 iface_id;
> +};
> +
> +struct ts_context_data {
> + struct list_head sess_list;
> + struct idr sess_ids;
> + /* Serializes access to this struct */
> + struct mutex mutex;
> +};
> +
> +struct tee_shm_pool *tstee_create_shm_pool(void);
> +int tstee_shm_register(struct tee_context *ctx, struct tee_shm *shm, struct page **pages,
> + size_t num_pages, unsigned long start);
> +int tstee_shm_unregister(struct tee_context *ctx, struct tee_shm *shm);
> +
> +#endif /* TSTEE_PRIVATE_H */
> diff --git a/include/uapi/linux/tee.h b/include/uapi/linux/tee.h
> index 23e57164693c..d0430bee8292 100644
> --- a/include/uapi/linux/tee.h
> +++ b/include/uapi/linux/tee.h
> @@ -56,6 +56,7 @@
> */
> #define TEE_IMPL_ID_OPTEE 1
> #define TEE_IMPL_ID_AMDTEE 2
> +#define TEE_IMPL_ID_TSTEE 3
>
> /*
> * OP-TEE specific capabilities
> --
> 2.34.1
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