[PATCH v4 3/3] tee: add MbedTEE driver
Jens Wiklander
jens.wiklander at oss.qualcomm.com
Thu Aug 20 01:10:32 PDT 2026
Hi,
On Wed, Aug 19, 2026 at 10:37 AM Xing Loong <xing.xl.loong at gmail.com> wrote:
>
> This patch adds a Linux TEE driver that communicates with
> MbedTEE OS, a Trusted Execution Environment for embedded
> systems (https://github.com/mbedtee) via a fixed shared-memory
> RPC protocol over architecture-specific transports:
>
> - ARM/ARM64: SMCCC fast/yield calls for REE-to-TEE requests;
> TEE-to-REE notifications via a GIC SPI edge interrupt.
> - RISC-V: REE submits commands by writing to a shared-memory
> r2t-ring that the TEE polls; the TEE notifies the REE by
> writing to t2r-ring and raising a platform IMSIC MSI.
> No REE-to-TEE interrupt is used.
>
> The driver implements the TEE subsystem interface (tee_driver_ops)
> and provides GlobalPlatform TEE Client API support, dynamic shared
> memory registration, and tee-supplicant support.
>
> Signed-off-by: Xing Loong <xing.xl.loong at gmail.com>
I took a quick look at the mbedtee project, and it appears to be a
one-person hobby project. Sounds like fun, but I wonder how meaningful
it is to upstream a kernel driver if you're the only user.
Cheers,
Jens
> ---
> Changes in v4:
> - Harden ring and RPC handling against malformed input:
> - Validate both ring indices; bound async ring skip and resync
> the reader on corrupt framing
> - Enforce RPC handler modes (COMPLETE_REE async-only, supplicant
> commands sync-only)
> - Reference-count rpc_call objects; fix use-after-free on
> interrupted calls; abort and free leftover calls at teardown
> - Add XA_FLAGS_LOCK_IRQ to the rpc_calls xarray
> - Fix supp_recv/supp_abort_all race; malformed supp_send unblocks
> the worker instead of hanging it
> - Reject TEE-changed parameter attributes
> - Report the wire error on failed supplicant requests; fail
> oversized requests instead of requeueing them forever
> - Wait for R2T ring space with a bounded backoff; bound
> COMPLETE_TEE retries and stop them at teardown
> - Match the supplicant context when dispatching supp_send
> - Access complete_work_pending under ring_lock
> - Serialize RPC submission against shutdown and reject new
> calls once teardown starts
> - Quiesce all RPC activity before tee_device_unregister() so
> parked waiters cannot deadlock teardown
> - Bound non-interruptible RISC-V waits so a hung TEE cannot
> block ioctls forever
> - Track closing state on sessions; reject concurrent
> close/invoke/cancel races
> - Quarantine TEE-owned call objects at release instead of
> risking a cross-world use-after-free
>
> Changes in v3:
> - No changes (driver unchanged since v2)
>
> Changes in v2:
> - Fix supp_release incorrectly aborting unclaimed requests on close
> - Fix potential tee_shm double-free on supp_recv error path
> - Fix async RPC ring skip leaving orphaned payload bytes
> - Fix COMPLETE_TEE retry to also handle transient -ENOMEM on RISC-V
> - Fix session leak on close_session allocation failure:
> release kernel resources before sending RPC
>
> ---
> Documentation/tee/index.rst | 1 +
> Documentation/tee/mbedtee.rst | 155 ++++++
> MAINTAINERS | 9 +
> drivers/tee/Kconfig | 3 +-
> drivers/tee/Makefile | 1 +
> drivers/tee/mbedtee/Kconfig | 20 +
> drivers/tee/mbedtee/Makefile | 11 +
> drivers/tee/mbedtee/core.c | 260 +++++++++
> drivers/tee/mbedtee/mbedtee_drv.h | 289 ++++++++++
> drivers/tee/mbedtee/mbedtee_msg.h | 219 ++++++++
> drivers/tee/mbedtee/rpc_callee.c | 697 +++++++++++++++++++++++++
> drivers/tee/mbedtee/rpc_callee_arm.c | 91 ++++
> drivers/tee/mbedtee/rpc_callee_riscv.c | 203 +++++++
> drivers/tee/mbedtee/rpc_caller.c | 697 +++++++++++++++++++++++++
> drivers/tee/mbedtee/rpc_caller_arm.c | 70 +++
> drivers/tee/mbedtee/rpc_caller_riscv.c | 238 +++++++++
> drivers/tee/mbedtee/shm_pool.c | 105 ++++
> drivers/tee/mbedtee/shm_pool.h | 15 +
> drivers/tee/mbedtee/supp.c | 311 +++++++++++
> include/uapi/linux/tee.h | 1 +
> 20 files changed, 3395 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/tee/mbedtee.rst
> create mode 100644 drivers/tee/mbedtee/Kconfig
> create mode 100644 drivers/tee/mbedtee/Makefile
> create mode 100644 drivers/tee/mbedtee/core.c
> create mode 100644 drivers/tee/mbedtee/mbedtee_drv.h
> create mode 100644 drivers/tee/mbedtee/mbedtee_msg.h
> create mode 100644 drivers/tee/mbedtee/rpc_callee.c
> create mode 100644 drivers/tee/mbedtee/rpc_callee_arm.c
> create mode 100644 drivers/tee/mbedtee/rpc_callee_riscv.c
> create mode 100644 drivers/tee/mbedtee/rpc_caller.c
> create mode 100644 drivers/tee/mbedtee/rpc_caller_arm.c
> create mode 100644 drivers/tee/mbedtee/rpc_caller_riscv.c
> create mode 100644 drivers/tee/mbedtee/shm_pool.c
> create mode 100644 drivers/tee/mbedtee/shm_pool.h
> create mode 100644 drivers/tee/mbedtee/supp.c
>
> diff --git a/Documentation/tee/index.rst b/Documentation/tee/index.rst
> index 10c3cec..6415855 100644
> --- a/Documentation/tee/index.rst
> +++ b/Documentation/tee/index.rst
> @@ -12,3 +12,4 @@ TEE Subsystem
> amd-tee
> ts-tee
> qtee
> + mbedtee
> diff --git a/Documentation/tee/mbedtee.rst b/Documentation/tee/mbedtee.rst
> new file mode 100644
> index 0000000..dfb57b8
> --- /dev/null
> +++ b/Documentation/tee/mbedtee.rst
> @@ -0,0 +1,155 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +==============================================
> +MbedTEE (Trusted Execution Environment)
> +==============================================
> +
> +The MbedTEE driver supports MbedTEE-based TEEs on ARM TrustZone (SMC calls,
> +GIC SPI notifications) and RISC-V IMSIC (shared-memory polling, MSI
> +notifications) platforms.
> +
> +The driver requires the REE and TEE CPUs that share the RPC shared memory to
> +be hardware coherent. In practice, the REE/TEE CPUs are expected to be in the
> +same CPU cluster, with coherent caches and shared visibility for the ring and
> +payload buffers.
> +
> +Communication overview
> +======================
> +
> +The driver communicates with the TEE using a fixed shared-memory RPC protocol
> +layered above the architecture-specific call mechanism.
> +
> +ARM platforms (SMC)
> +-------------------
> +
> +On ARM and AArch64 platforms, the driver uses ARM SMC Calling Convention
> +(SMCCC) to issue fast calls and yield calls to the TEE:
> +
> +- **Fast calls** (MBEDTEE_RPC_OS_VERSION, MBEDTEE_RPC_SUPPORT_YIELD,
> + MBEDTEE_RPC_COMPLETE_TEE) are self-contained SMC calls that do
> + not rely on shared-memory RPC structures.
> +
> +- **Yield calls** post the physical address of an ``rpc_cmd`` structure
> + in shared memory to the TEE. The TEE may issue RPC requests back to the
> + driver before the call completes; kernel-directed RPCs are handled
> + directly, while supplicant RPCs (filesystem and RPMB) are forwarded to
> + tee-supplicant.
> +
> +TEE-to-REE notifications on ARM are delivered via a GIC SPI edge interrupt
> +specified in the device tree (``interrupts`` property).
> +
> +RISC-V platforms
> +----------------
> +
> +On RISC-V platforms, SMCCC is not available. Communication is split into two
> +directions:
> +
> +- **REE to TEE (R2T)**: The driver submits commands by writing the physical
> + address of an ``rpc_cmd`` structure to a REE-to-TEE ring buffer
> + (``r2t-ring``). The TEE polls that ring for new commands. No interrupt
> + notification is sent; the protocol relies on TEE-side polling.
> +
> +- **TEE to REE (T2R)**: The TEE writes an ``rpc_cmd`` into the TEE-to-REE
> + ring and raises an IMSIC MSI to notify the REE driver. The MSI is
> + allocated at runtime via the ``msi-parent`` DT property and its identity
> + is published in ``callee_imsic_id``; ``callee_hartid`` tracks the
> + target hart for migration during CPU hotplug. No SBI ecall is involved.
> +
> +RISC-V REE-to-TEE polling rationale
> +-----------------------------------
> +
> +The REE-to-TEE direction uses polling-only on RISC-V to avoid direct
> +notification interrupt writes from Linux to TEE-owned interrupt files.
> +This design is platform-independent and does not require ownership of
> +TEE-only hart interrupt files. The TEE-to-REE direction remains fully
> +functional via standard Linux MSI notifications and does not depend on
> +REE-to-TEE notification latency.
> +
> +Shared memory regions
> +=====================
> +
> +Two or three fixed shared memory regions are described in the device tree:
> +
> +``t2r-ring``
> + Ring buffer used by the TEE to post RPC request notifications to the REE
> + driver. Present on all platforms.
> +
> +``t2r-shm``
> + Shared memory region carrying the actual ``rpc_cmd`` payloads for
> + TEE-to-REE RPCs. Present on all platforms.
> +
> +``r2t-ring``
> + Ring buffer used by the REE driver to submit commands to the TEE on
> + RISC-V IMSIC platforms.
> +
> +RPC protocol
> +============
> +
> +The TEE and REE communicate through the ``rpc_cmd`` structure in shared memory
> +and ring buffers::
> +
> + struct rpc_cmd {
> + u32 id; /* RPC function ID */
> + u16 size; /* payload size in bytes */
> + u8 interrupted; /* set if wait was interrupted */
> + u8 reserved; /* explicit alignment padding */
> + s32 ret; /* return value */
> + u32 pad; /* explicit alignment padding */
> + u64 waiter_id; /* sync RPC request ID echoed on completion */
> + u64 shm; /* physical address of payload (sync RPC) */
> + u64 data[]; /* inline payload (async RPC) */
> + };
> +
> + struct rpc_ringbuf {
> + u32 wr; /* producer write pointer */
> + u32 rd; /* consumer read pointer */
> + u32 callee_ready; /* callee ready flag */
> + u32 callee_imsic_id; /* RISC-V only: IMSIC local interrupt id */
> + u32 callee_hartid; /* RISC-V only: target hart-id for T2R notification */
> + u32 reserved; /* padding, must be zero */
> + u8 mem[];
> + };
> +
> +For RISC-V T2R MSI, one MSI message targets one hart IMSIC file at a time.
> +The wire-visible state is split between ``callee_imsic_id`` and
> +``callee_hartid`` in the ring header; Linux may retarget the MSI across
> +online CPUs via ``irq_set_affinity()``, and the driver updates those fields
> +to match the selected hart.
> +
> +
> +
> +Architecture diagram::
> +
> + User space Kernel TEE side
> + ~~~~~~~~~~ ~~~~~~ ~~~~~~~~~~~~
> + +--------+ +--------------+
> + | Client | | Trusted App |
> + +--------+ +--------------+
> + /\ /\
> + || +------------+ ||
> + || | MbedTEE- | \/
> + || | supplicant | +--------------+
> + || +------------+ | TEE Internal |
> + \/ /\ | API |
> + +-------+ || +--------------+
> + | TEE | || +---------+---------------+ | MbedTEE |
> + | Client| || | TEE | MbedTEE | | Trusted OS |
> + | API | \/ | subsys | client driver | +--------------+
> + +-------+-------------+-----+--------+----------+----+ |
> + | Generic TEE API | | RPC (cmd/ring)| |
> + | IOCTL (TEE_IOC_*) | | SMC / IMSIC | |
> + +---------------------------+ +---------------+--------------+
> +
> +Device tree binding
> +===================
> +
> +See Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml for the
> +complete device tree binding specification, including the RISC-V
> +``msi-parent`` requirement.
> +
> +References
> +==========
> +
> +- [1] MbedTEE project: https://github.com/mbedtee
> +- [2] ARM SMC Calling Convention: https://developer.arm.com/architectures/system-architectures/software-standards/smccc
> +- [3] RISC-V IMSIC specification: https://github.com/riscv/riscv-aia
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c8d4b91..344b82b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -15920,6 +15920,15 @@ F: Documentation/devicetree/bindings/net/dsa/maxlinear,mxl862xx.yaml
> F: drivers/net/dsa/mxl862xx/
> F: net/dsa/tag_mxl862xx.c
>
> +MBEDTEE TEE DRIVER
> +M: Xing Loong <xing.xl.loong at gmail.com>
> +L: op-tee at lists.trustedfirmware.org (moderated for non-subscribers)
> +S: Maintained
> +W: https://github.com/mbedtee
> +F: Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml
> +F: Documentation/tee/mbedtee.rst
> +F: drivers/tee/mbedtee/
> +
> MCAN DEVICE DRIVER
> M: Markus Schneider-Pargmann <msp at baylibre.com>
> L: linux-can at vger.kernel.org
> diff --git a/drivers/tee/Kconfig b/drivers/tee/Kconfig
> index 98c3ad0..3dc3439 100644
> --- a/drivers/tee/Kconfig
> +++ b/drivers/tee/Kconfig
> @@ -2,7 +2,7 @@
> # Generic Trusted Execution Environment Configuration
> menuconfig TEE
> tristate "Trusted Execution Environment support"
> - depends on HAVE_ARM_SMCCC || COMPILE_TEST || CPU_SUP_AMD
> + depends on HAVE_ARM_SMCCC || RISCV || COMPILE_TEST || CPU_SUP_AMD
> select CRYPTO_LIB_SHA1
> select DMA_SHARED_BUFFER
> select GENERIC_ALLOCATOR
> @@ -21,5 +21,6 @@ source "drivers/tee/optee/Kconfig"
> source "drivers/tee/amdtee/Kconfig"
> source "drivers/tee/tstee/Kconfig"
> source "drivers/tee/qcomtee/Kconfig"
> +source "drivers/tee/mbedtee/Kconfig"
>
> endif
> diff --git a/drivers/tee/Makefile b/drivers/tee/Makefile
> index 3239b91..33117ea 100644
> --- a/drivers/tee/Makefile
> +++ b/drivers/tee/Makefile
> @@ -8,3 +8,4 @@ obj-$(CONFIG_OPTEE) += optee/
> obj-$(CONFIG_AMDTEE) += amdtee/
> obj-$(CONFIG_ARM_TSTEE) += tstee/
> obj-$(CONFIG_QCOMTEE) += qcomtee/
> +obj-$(CONFIG_MBEDTEE) += mbedtee/
> diff --git a/drivers/tee/mbedtee/Kconfig b/drivers/tee/mbedtee/Kconfig
> new file mode 100644
> index 0000000..b1fa38a
> --- /dev/null
> +++ b/drivers/tee/mbedtee/Kconfig
> @@ -0,0 +1,20 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +# MbedTEE Trusted Execution Environment Configuration
> +config MBEDTEE
> + tristate "MbedTEE"
> + depends on MMU && OF
> + depends on ((ARM || ARM64) && HAVE_ARM_SMCCC) || (RISCV && GENERIC_MSI_IRQ)
> + help
> + This enables the MbedTEE Trusted Execution Environment (TEE)
> + driver.
> +
> + The driver supports ARM TrustZone (SMC calls, GIC SPI notifications)
> + and RISC-V IMSIC (shared-memory polling, MSI notifications), with
> + GlobalPlatform client API via /dev/tee*.
> +
> + The DT node should be under a firmware node and have compatible =
> + "mbedtee,tee" with the RPC ring buffer addresses and,
> + for ARM/ARM64, an interrupt property for TEE-to-REE notifications.
> + See Documentation/tee/mbedtee.rst for protocol details.
> +
> + If unsure, say N.
> diff --git a/drivers/tee/mbedtee/Makefile b/drivers/tee/mbedtee/Makefile
> new file mode 100644
> index 0000000..309eb6d
> --- /dev/null
> +++ b/drivers/tee/mbedtee/Makefile
> @@ -0,0 +1,11 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +obj-$(CONFIG_MBEDTEE) += mbedtee.o
> +
> +mbedtee-y += core.o
> +mbedtee-y += supp.o
> +mbedtee-y += shm_pool.o
> +mbedtee-y += rpc_caller.o rpc_callee.o
> +mbedtee-$(CONFIG_ARM) += rpc_caller_arm.o rpc_callee_arm.o
> +mbedtee-$(CONFIG_ARM64) += rpc_caller_arm.o rpc_callee_arm.o
> +mbedtee-$(CONFIG_RISCV) += rpc_caller_riscv.o rpc_callee_riscv.o
> diff --git a/drivers/tee/mbedtee/core.c b/drivers/tee/mbedtee/core.c
> new file mode 100644
> index 0000000..4a027a7
> --- /dev/null
> +++ b/drivers/tee/mbedtee/core.c
> @@ -0,0 +1,260 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2020 Xing Loong <xing.xl.loong at gmail.com>
> + */
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/errno.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/string.h>
> +#include <linux/tee_drv.h>
> +#include <linux/types.h>
> +
> +#include "mbedtee_drv.h"
> +#include "shm_pool.h"
> +
> +int mbedtee_get_resource(struct device_node *node,
> + const char *name, struct resource *res)
> +{
> + struct device_node *rmem;
> + int idx;
> + int ret;
> +
> + idx = of_property_match_string(node, "memory-region-names", name);
> + if (idx < 0)
> + return idx;
> +
> + rmem = of_parse_phandle(node, "memory-region", idx);
> + if (!rmem)
> + return -ENODEV;
> +
> + ret = of_address_to_resource(rmem, 0, res);
> + of_node_put(rmem);
> +
> + if (ret)
> + return ret;
> +
> + res->name = name;
> + return 0;
> +}
> +
> +static void mbedtee_get_version(struct tee_device *teedev,
> + struct tee_ioctl_version_data *vers)
> +{
> + struct tee_ioctl_version_data v = {
> + .impl_id = TEE_IMPL_ID_MBEDTEE,
> + .impl_caps = 0,
> + .gen_caps = TEE_GEN_CAP_GP | TEE_GEN_CAP_REG_MEM |
> + TEE_GEN_CAP_MEMREF_NULL,
> + };
> +
> + *vers = v;
> +}
> +
> +static int mbedtee_open(struct tee_context *ctx)
> +{
> + struct mbedtee_context_data *ctxdata;
> +
> + ctxdata = kzalloc_obj(*ctxdata, GFP_KERNEL);
> + if (!ctxdata)
> + return -ENOMEM;
> +
> + mutex_init(&ctxdata->mutex);
> + INIT_LIST_HEAD(&ctxdata->sess_list);
> +
> + ctx->data = ctxdata;
> + ctx->cap_memref_null = true;
> +
> + return 0;
> +}
> +
> +static void mbedtee_release(struct tee_context *ctx)
> +{
> + struct mbedtee_device *mbedtee = tee_get_drvdata(ctx->teedev);
> + struct mbedtee_context_data *d = ctx->data;
> + struct mbedtee_session *s, *n;
> +
> + if (!d)
> + return;
> +
> + if (d->is_supp_ctx) {
> + mbedtee_supp_release(&mbedtee->supp, ctx);
> + } else {
> + list_for_each_entry_safe(s, n, &d->sess_list, list_node) {
> + u32 session_id = s->session_id;
> +
> + if (!mbedtee_close_session(ctx, session_id))
> + continue;
> +
> + /*
> + * A non-zero return can mean the session was already
> + * dropped (e.g. -ESHUTDOWN during teardown) or kept on a
> + * transient error. Re-look it up: kfree(NULL) is a no-op
> + * in the former case, a force-removal in the latter.
> + */
> + mutex_lock(&d->mutex);
> + s = mbedtee_find_session_locked(d, session_id);
> + if (s)
> + list_del(&s->list_node);
> + mutex_unlock(&d->mutex);
> + kfree(s);
> + }
> + }
> +
> + kfree(d);
> + ctx->data = NULL;
> +}
> +
> +static const struct tee_driver_ops mbedtee_ops = {
> + .get_version = mbedtee_get_version,
> + .open = mbedtee_open,
> + .release = mbedtee_release,
> + .open_session = mbedtee_open_session,
> + .close_session = mbedtee_close_session,
> + .invoke_func = mbedtee_invoke_func,
> + .cancel_req = mbedtee_cancel_req,
> + .supp_recv = mbedtee_supp_recv,
> + .supp_send = mbedtee_supp_send,
> + .shm_register = mbedtee_shm_register,
> + .shm_unregister = mbedtee_shm_unregister,
> +};
> +
> +static const struct tee_desc mbedtee_desc = {
> + .name = "mbedtee",
> + .ops = &mbedtee_ops,
> + .owner = THIS_MODULE,
> +};
> +
> +static int mbedtee_probe(struct platform_device *pdev)
> +{
> + int ret;
> + long version;
> + long yield;
> + struct tee_shm_pool *pool;
> + struct tee_device *teedev;
> + struct mbedtee_device *mbedtee;
> +
> + mbedtee = devm_kzalloc(&pdev->dev, sizeof(*mbedtee), GFP_KERNEL);
> + if (!mbedtee)
> + return -ENOMEM;
> +
> + mbedtee->dev = &pdev->dev;
> + xa_init_flags(&mbedtee->rpc_calls, XA_FLAGS_ALLOC1 | XA_FLAGS_LOCK_IRQ);
> + mutex_init(&mbedtee->rpc_calls_mutex);
> + mbedtee_supp_init(&mbedtee->supp);
> +
> + /*
> + * R2T must be ready before T2R is advertised: synchronous T2R RPC
> + * work replies with COMPLETE_TEE over the R2T path.
> + */
> + ret = mbedtee_r2t_init(mbedtee);
> + if (ret != 0)
> + goto err_supp;
> +
> + ret = mbedtee_rpc_init(mbedtee);
> + if (ret != 0)
> + goto err_r2t;
> +
> + version = mbedtee_rpc_fastcall(mbedtee, MBEDTEE_RPC_OS_VERSION, 0, 0, 0);
> + if (version < 0) {
> + dev_err(&pdev->dev, "MBEDTEE_RPC_OS_VERSION failed: %ld\n", version);
> + ret = version;
> + goto err_rpc;
> + }
> +
> + if (!MBEDTEE_VALID_VERSION(version)) {
> + dev_err(&pdev->dev, "mbedtee not present (version=0x%lx)\n",
> + version);
> + ret = -ENODEV;
> + goto err_rpc;
> + }
> +
> + yield = mbedtee_rpc_fastcall(mbedtee, MBEDTEE_RPC_SUPPORT_YIELD, 0, 0, 0);
> + dev_info(&pdev->dev, "version: 0x%06lx yield: %ld\n", version, yield);
> +
> + pool = mbedtee_shm_pool_alloc_pages();
> + if (IS_ERR(pool)) {
> + ret = PTR_ERR(pool);
> + goto err_rpc;
> + }
> +
> + teedev = tee_device_alloc(&mbedtee_desc, &pdev->dev, pool, mbedtee);
> + if (IS_ERR(teedev)) {
> + ret = PTR_ERR(teedev);
> + goto err_pool;
> + }
> +
> + ret = tee_device_register(teedev);
> + if (ret)
> + goto err_teedev;
> +
> + mbedtee->teedev = teedev;
> + mbedtee->version = version;
> + mbedtee->yield = !!yield;
> + mbedtee->pool = pool;
> + platform_set_drvdata(pdev, mbedtee);
> +
> + dev_dbg(&pdev->dev, "client initialized\n");
> + return 0;
> +
> +err_teedev:
> + tee_device_unregister(teedev);
> +err_pool:
> + tee_shm_pool_free(pool);
> +err_rpc:
> + mbedtee_rpc_uninit(mbedtee);
> +err_r2t:
> + mbedtee_r2t_uninit(mbedtee);
> +err_supp:
> + mbedtee_supp_uninit(&mbedtee->supp);
> + mbedtee_rpc_calls_release(mbedtee);
> + return ret;
> +}
> +
> +static void mbedtee_remove(struct platform_device *pdev)
> +{
> + struct mbedtee_device *mbedtee = platform_get_drvdata(pdev);
> +
> + /*
> + * Quiesce and wake all RPC waiters before tee_device_unregister(),
> + * which blocks until every context is released; a waiter still parked
> + * in a completion would otherwise deadlock teardown.
> + */
> + mbedtee_rpc_stop(mbedtee);
> + tee_device_unregister(mbedtee->teedev);
> + /*
> + * Drain T2R before tearing down R2T: queued RPC work may still need
> + * to send COMPLETE_TEE over R2T. Destroy the supplicant mutex only
> + * after RPC work can no longer enter mbedtee_supp_handler().
> + */
> + mbedtee_rpc_uninit(mbedtee);
> + mbedtee_r2t_uninit(mbedtee);
> + mbedtee_supp_uninit(&mbedtee->supp);
> + tee_shm_pool_free(mbedtee->pool);
> + mbedtee_rpc_calls_release(mbedtee);
> +}
> +
> +static const struct of_device_id mbedtee_dt_match[] = {
> + { .compatible = "mbedtee,tee" },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, mbedtee_dt_match);
> +
> +static struct platform_driver mbedtee_driver = {
> + .probe = mbedtee_probe,
> + .remove = mbedtee_remove,
> + .driver = {
> + .name = "mbedtee",
> + .of_match_table = mbedtee_dt_match,
> + },
> +};
> +module_platform_driver(mbedtee_driver);
> +
> +MODULE_AUTHOR("Xing Loong <xing.xl.loong at gmail.com>");
> +MODULE_DESCRIPTION("MbedTEE Trusted Execution Environment driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/tee/mbedtee/mbedtee_drv.h b/drivers/tee/mbedtee/mbedtee_drv.h
> new file mode 100644
> index 0000000..fe2bcfa
> --- /dev/null
> +++ b/drivers/tee/mbedtee/mbedtee_drv.h
> @@ -0,0 +1,289 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2020 Xing Loong <xing.xl.loong at gmail.com>
> + */
> +#ifndef MBEDTEE_DRV_H
> +#define MBEDTEE_DRV_H
> +
> +#include <linux/types.h>
> +#include <linux/errno.h>
> +#include <linux/atomic.h>
> +#include <linux/of.h>
> +#include <linux/ioport.h>
> +#include <linux/tee_drv.h>
> +#include <linux/tee_core.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +#include <linux/msi.h>
> +#include <linux/mutex.h>
> +#include <linux/workqueue.h>
> +#include <linux/cpuhotplug.h>
> +#include <linux/cpumask.h>
> +#include <linux/refcount.h>
> +#include <linux/xarray.h>
> +#include "mbedtee_msg.h"
> +#include "shm_pool.h"
> +
> +/*
> + * GlobalPlatform TEE Client API return codes/origins
> + * used by this driver. Only the codes actually
> + * referenced in the driver are defined here.
> + */
> +#define TEEC_SUCCESS 0x00000000
> +#define TEEC_ERROR_OUT_OF_MEMORY 0xFFFF000C
> +#define TEEC_ERROR_COMMUNICATION 0xFFFF000E
> +
> +#define TEEC_ORIGIN_COMMS 0x00000002
> +
> +#define MBEDTEE_VERSION_MAJOR 1
> +#define MBEDTEE_VALID_VERSION(x) (((x) >> 16) == MBEDTEE_VERSION_MAJOR)
> +
> +/* Maximum payload size for inline (async) RPC data. */
> +#define MBEDTEE_ASYNC_RPC_DATA_MAX 256
> +
> +struct rpc_transport_ops;
> +struct mbedtee_rpc_call;
> +struct mbedtee_supp_req;
> +struct mbedtee_device;
> +
> +struct rpc_work {
> + struct work_struct work;
> + struct mbedtee_device *mbedtee;
> + u64 waiter_id;
> + size_t size;
> + bool complete_only;
> + /* Points to ctx->rpc_data (async) or into t2r_shm (sync) */
> + void *data;
> + void (*func)(struct mbedtee_device *mbedtee, void *data, size_t size);
> +};
> +
> +struct mbedtee_t2r_ctx {
> + spinlock_t ring_lock; /* protects T2R ring producer/consumer state */
> + void *t2r_shm;
> + phys_addr_t t2r_shm_phys;
> + resource_size_t t2r_shm_sz;
> + struct rpc_ringbuf *t2r_ring;
> + u32 t2r_ring_sz;
> + u32 t2r_ring_rd;
> +
> + void (*rpc_handlers[MBEDTEE_RPC_MAX])(struct mbedtee_device *mbedtee,
> + void *data, size_t size);
> +
> + /*
> + * Inline buffer for async RPC payloads (waiter_id == 0).
> + * Sync RPC payloads (waiter_id != 0) live in shared memory (t2r_shm).
> + */
> + u8 rpc_data[MBEDTEE_ASYNC_RPC_DATA_MAX];
> +
> + /*
> + * CPU-hotplug tracking for T2R interrupt delivery.
> + * callee_cpus: shadow of cpu_online_mask maintained by the core
> + * callee layer (rpc_callee.c) for both ARM and RISC-V; used by
> + * ARM to feed irq_set_affinity() and by RISC-V as the gate for
> + * MSI migration decisions.
> + * callee_virq: single MSI virq currently pinned to one CPU
> + * (RISC-V IMSIC only; 0 for ARM).
> + * hp_node: per-instance node for cpuhp_setup_state_multi().
> + */
> + struct cpumask callee_cpus;
> + int callee_virq;
> + struct hlist_node hp_node;
> + bool cpuhp_added;
> + bool complete_work_pending;
> + bool pending_async;
> + bool stopping; /* set at teardown to stop COMPLETE_TEE retries */
> + u32 pending_size;
> + struct workqueue_struct *rpc_wq;
> + struct rpc_work complete_work;
> + void (*pending_func)(struct mbedtee_device *mbedtee,
> + void *data, size_t size);
> +};
> +
> +struct mbedtee_r2t_ctx {
> + spinlock_t lock; /* protects R2T ring write-side state */
> + struct rpc_ringbuf *ring;
> + u32 ring_sz;
> + u32 ring_wr;
> + bool stopping; /* set at teardown to abort ring-full waits */
> +};
> +
> +struct mbedtee_rpc_transport_ctx {
> + int rpc_notify_virq;
> + struct msi_msg rpc_msi_msg;
> +};
> +
> +struct mbedtee_supp {
> + struct mutex mutex; /* serializes supp request queue and active requests */
> + struct tee_context *ctx;
> + bool shutting_down;
> + struct list_head reqs;
> + struct list_head active_reqs;
> + struct completion reqs_c;
> +};
> +
> +struct mbedtee_device {
> + u32 version;
> + bool yield;
> + struct device *dev;
> + struct tee_device *teedev;
> + struct tee_shm_pool *pool;
> + struct mbedtee_supp supp;
> + struct xarray rpc_calls;
> + struct mutex rpc_calls_mutex; /* serializes submission and shutdown */
> + bool stopping;
> + atomic_long_t rpc_call_seq;
> + const struct rpc_transport_ops *rpc_ops;
> + struct mbedtee_t2r_ctx t2r;
> + struct mbedtee_r2t_ctx r2t;
> + struct mbedtee_rpc_transport_ctx transport;
> +};
> +
> +struct mbedtee_rpc_call {
> + struct completion c;
> + phys_addr_t rpc_phys;
> + u32 state;
> + /* One reference for the caller, one for the XArray entry. */
> + refcount_t refs;
> + /*
> + * Wire-format rpc_cmd with inline data[] payload.
> + * MUST be the last field: rpc.data[] is a flexible array.
> + */
> + struct rpc_cmd rpc;
> +};
> +
> +struct mbedtee_session {
> + struct list_head list_node;
> + u32 session_id;
> + bool closing;
> +};
> +
> +struct mbedtee_context_data {
> + bool is_supp_ctx;
> + struct mutex mutex; /* serializes session list updates */
> + struct list_head sess_list;
> +};
> +
> +struct mbedtee_session *
> +mbedtee_find_session_locked(struct mbedtee_context_data *ctxdata,
> + u32 session_id);
> +
> +static inline phys_addr_t mbedtee_virt_to_phys(void *va)
> +{
> + if (is_vmalloc_or_module_addr(va))
> + return page_to_phys(vmalloc_to_page(va)) +
> + offset_in_page(va);
> +
> + return virt_to_phys(va);
> +}
> +
> +int mbedtee_get_resource(struct device_node *node,
> + const char *name, struct resource *res);
> +
> +/*
> + * RPC transport operations -- implemented per-architecture.
> + *
> + * Caller (rpc_caller_{arm,riscv}.c) platform differences:
> + * fastcall: ARM/ARM64 - direct SMC (arm_smccc_smc), synchronous,
> + * never returns -ENOSPC.
> + * RISC-V - writes rpc_cmd phys addr to the r2t ring
> + * buffer, then waits for TEE completion via the t2r
> + * ring. Despite the "fastcall" name this is a
> + * synchronous ring-buffer round-trip; it may return
> + * -ENOSPC when the r2t ring is full, and the caller
> + * must retry (see rpc_routine() for the
> + * MBEDTEE_RPC_COMPLETE_TEE retry loop).
> + * yieldcall: ARM/ARM64 - one SMC posting rpc_cmd phys addr, waits
> + * for completion.
> + * RISC-V - writes rpc_cmd phys addr to r2t ring, waits
> + * for completion.
> + * Callee (rpc_callee_{arm,riscv}.c) platform differences:
> + * notify: ARM/ARM64 - GIC SPI; the TEE broadcasts via GIC
> + * hardware (GICv2 ITARGETS=0xFF, GICv3 IROUTER.IRM=1).
> + * Ring metadata unchanged on CPU affinity events.
> + * RISC-V - IMSIC MSI; the driver writes callee_hartid
> + * and callee_imsic_id into the ring so the TEE knows
> + * where to send the MSI. The affinity handler updates
> + * both ring fields when the callee CPU goes offline.
> + *
> + * init: Set up the interrupt delivery mechanism (MSI on RISC-V,
> + * GIC/OF-IRQ on ARM/ARM64) and, on RISC-V, write
> + * ring->callee_hartid and ring->callee_imsic_id. @handler
> + * is the hard-IRQ handler that drains the ring buffer and
> + * dispatches RPC commands.
> + * uninit: Tear down and free all interrupt resources.
> + * update_affinity: Migrate T2R interrupt delivery to @new_cpu. Called by the
> + * common cpuhp handler when the current callee CPU goes
> + * offline. On RISC-V IMSIC, must update ring->callee_hartid
> + * and ring->callee_imsic_id. ARM uses GIC hardware routing
> + * and requires no ring update.
> + *
> + * The getter is implemented per-architecture in rpc_callee_{arm,riscv}.c;
> + * only one is linked per build.
> + */
> +struct rpc_transport_ops {
> + int (*init)(struct mbedtee_device *mbedtee, struct rpc_ringbuf *ring,
> + irq_handler_t handler);
> + void (*uninit)(struct mbedtee_device *mbedtee);
> + int (*update_affinity)(struct mbedtee_device *mbedtee,
> + unsigned int new_cpu);
> +};
> +
> +const struct rpc_transport_ops *mbedtee_get_rpc_transport_ops(void);
> +
> +/* rpc-callee.c */
> +int mbedtee_rpc_init(struct mbedtee_device *mbedtee);
> +void mbedtee_rpc_stop(struct mbedtee_device *mbedtee);
> +void mbedtee_rpc_uninit(struct mbedtee_device *mbedtee);
> +irqreturn_t mbedtee_rpc_irq_handler(int irq, void *dev_id);
> +
> +/* rpc_caller.c */
> +int mbedtee_rpc_call_alloc(struct mbedtee_device *mbedtee,
> + size_t payload_size, struct mbedtee_rpc_call **call);
> +void mbedtee_rpc_call_free(struct mbedtee_device *mbedtee,
> + struct mbedtee_rpc_call *call);
> +void mbedtee_rpc_complete_call(struct mbedtee_device *mbedtee,
> + u64 waiter_id);
> +void mbedtee_rpc_calls_abort(struct mbedtee_device *mbedtee);
> +void mbedtee_rpc_calls_release(struct mbedtee_device *mbedtee);
> +long mbedtee_rpc_wait_for_completion(struct mbedtee_device *mbedtee,
> + struct mbedtee_rpc_call *call, bool killable);
> +long mbedtee_rpc_wait_for_completion_timeout(struct mbedtee_device *mbedtee,
> + struct mbedtee_rpc_call *call,
> + unsigned long timeout);
> +int mbedtee_open_session(struct tee_context *ctx,
> + struct tee_ioctl_open_session_arg *arg,
> + struct tee_param *param);
> +int mbedtee_close_session(struct tee_context *ctx, u32 session);
> +int mbedtee_invoke_func(struct tee_context *ctx,
> + struct tee_ioctl_invoke_arg *arg,
> + struct tee_param *param);
> +int mbedtee_cancel_req(struct tee_context *ctx, u32 cancel_id,
> + u32 session);
> +int mbedtee_shm_register(struct tee_context *ctx, struct tee_shm *shm,
> + struct page **pages, size_t num_pages, unsigned long start);
> +int mbedtee_shm_unregister(struct tee_context *ctx, struct tee_shm *shm);
> +
> +/* rpc-caller-{arm,riscv}.c */
> +long mbedtee_rpc_yieldcall(struct mbedtee_device *mbedtee,
> + unsigned long fn, struct mbedtee_rpc_call *call,
> + bool interruptible);
> +long mbedtee_rpc_fastcall(struct mbedtee_device *mbedtee,
> + unsigned long fn, unsigned long a0,
> + unsigned long a1, unsigned long a2);
> +int mbedtee_r2t_init(struct mbedtee_device *mbedtee);
> +void mbedtee_r2t_stop(struct mbedtee_device *mbedtee);
> +void mbedtee_r2t_uninit(struct mbedtee_device *mbedtee);
> +
> +/* supp.c */
> +void mbedtee_supp_init(struct mbedtee_supp *supp);
> +void mbedtee_supp_uninit(struct mbedtee_supp *supp);
> +void mbedtee_supp_release(struct mbedtee_supp *supp, struct tee_context *ctx);
> +void mbedtee_supp_abort_all(struct mbedtee_supp *supp);
> +void mbedtee_supp_handler(struct mbedtee_device *mbedtee,
> + u32 func, void *data, size_t size);
> +int mbedtee_supp_recv(struct tee_context *ctx, u32 *func,
> + u32 *num_params, struct tee_param *param);
> +int mbedtee_supp_send(struct tee_context *ctx, u32 ret,
> + u32 num_params, struct tee_param *param);
> +
> +#endif /* MBEDTEE_DRV_H */
> diff --git a/drivers/tee/mbedtee/mbedtee_msg.h b/drivers/tee/mbedtee/mbedtee_msg.h
> new file mode 100644
> index 0000000..deb2d8c
> --- /dev/null
> +++ b/drivers/tee/mbedtee/mbedtee_msg.h
> @@ -0,0 +1,219 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2020 Xing Loong <xing.xl.loong at gmail.com>
> + *
> + * MbedTEE RPC wire protocol between REE (Linux) and TEE (MbedTEE OS).
> + *
> + * This header is the Linux-kernel mirror of
> + * mbedtee-os/drivers/rpc/include/rpc/rpc.h. Both copies MUST define
> + * identical struct layouts. The static_assert() checks at the bottom
> + * of this file (and the _Static_assert() checks in rpc.h) enforce this
> + * contract at compile time on every architecture.
> + *
> + * Type mapping (wire -> Linux kernel alias):
> + * uint8_t -> u8 -- boolean flag / padding byte
> + * uint16_t -> u16 -- byte-count field (< 64 KiB payload limit)
> + * uint32_t -> u32 -- 32-bit ID, counter, flag, or enum
> + * int32_t -> s32 -- function-defined signed result code
> + * uint64_t -> u64 -- physical address, kernel pointer token, or size
> + *
> + * Using u64 for all pointer-sized fields eliminates ABI width mismatches
> + * in mixed-width configurations (e.g. RV64 REE + RV32 TEE, or ARM32-LPAE
> + * REE + ARM32 TEE). It also prevents phys_addr_t/unsigned-long confusion
> + * when CONFIG_PHYS_ADDR_T_64BIT=y on a 32-bit REE kernel.
> + */
> +
> +#ifndef MBEDTEE_MSG_H
> +#define MBEDTEE_MSG_H
> +
> +#include <linux/bits.h>
> +#include <linux/build_bug.h>
> +#include <linux/types.h>
> +
> +/*
> + * Fastcall / yield-call classification
> + */
> +#define MBEDTEE_RPC_FASTCALL BIT(31)
> +#define MBEDTEE_RPC_IS_FASTCALL(fn) ((fn) & MBEDTEE_RPC_FASTCALL)
> +
> +/*
> + * REE -> TEE fast calls
> + */
> +#define MBEDTEE_RPC_OS_VERSION (0x0100 | MBEDTEE_RPC_FASTCALL)
> +#define MBEDTEE_RPC_SUPPORT_YIELD (0x0101 | MBEDTEE_RPC_FASTCALL)
> +#define MBEDTEE_RPC_COMPLETE_TEE (0x0102 | MBEDTEE_RPC_FASTCALL)
> +
> +/*
> + * REE -> TEE yield calls
> + */
> +#define MBEDTEE_RPC_OPEN_SESSION 1
> +#define MBEDTEE_RPC_INVOKE_SESSION 2
> +#define MBEDTEE_RPC_CLOSE_SESSION 3
> +#define MBEDTEE_RPC_REGISTER_SHM 5
> +#define MBEDTEE_RPC_UNREGISTER_SHM 6
> +#define MBEDTEE_RPC_CANCEL 7
> +
> +/*
> + * TEE -> REE RPC calls
> + */
> +#define MBEDTEE_RPC_COMPLETE_REE 0
> +#define MBEDTEE_RPC_REETIME 1
> +#define MBEDTEE_RPC_REEFS 2
> +#define MBEDTEE_RPC_RPMB 3
> +#define MBEDTEE_RPC_MAX 4
> +
> +/*
> + * Supplicant types (TEE -> REE -> tee-supplicant)
> + */
> +#define MBEDTEE_SUPP_REEFS 1
> +#define MBEDTEE_SUPP_RPMB 2
> +
> +/* MbedTEE RPC protocol uses 4 KiB page units regardless of host PAGE_SIZE. */
> +#define MBEDTEE_PAGE_SIZE 4096UL
> +
> +/*
> + * REE <-> TEE RPC call command (wire format, 32 bytes fixed header).
> + *
> + * Fixed layout:
> + * +0 id u32 - RPC function identifier
> + * +4 size u16 - inline payload byte count (0..65535)
> + * +6 interrupted u8 - set by REE when caller is interrupted
> + * +7 reserved u8 - must be zero (explicit alignment pad)
> + * +8 ret s32 - return value written by callee
> + * +12 pad u32 - must be zero (explicit alignment pad)
> + * +16 waiter_id u64 - sync RPC request ID echoed on completion
> + * +24 shm u64 - physical address of sync-RPC shared memory
> + * +32 data[] u64 - inline payload (waiter_id==0) or empty
> + *
> + * Yield-call contract:
> + * - Session/control RPCs return GlobalPlatform result codes here.
> + * - Host-local errno values must be translated before being put on the wire.
> + * - Fast calls may use function-specific return values.
> + */
> +struct rpc_cmd {
> + u32 id;
> + u16 size;
> + u8 interrupted;
> + u8 reserved;
> + s32 ret;
> + u32 pad;
> + u64 waiter_id;
> + u64 shm;
> + u64 data[];
> +};
> +
> +/*
> + * REE -> TEE pages for GP shared memory.
> + *
> + * All fields are u64 so the layout is identical when REE is 64-bit
> + * but TEE is 32-bit (physical addresses, sizes and counts use 64 bits).
> + */
> +struct rpc_memref {
> + u64 id;
> + u64 pages;
> + u64 offset;
> + u64 size;
> + u64 cnt;
> +};
> +
> +/*
> + * REE -> TEE parameter entry: value or shared memory reference.
> + */
> +union rpc_tee_param {
> + struct rpc_memref memref;
> +
> + struct {
> + u32 a;
> + u32 b;
> + } value;
> +};
> +
> +/*
> + * REE -> TEE parameters for RPC session operations
> + * (MBEDTEE_RPC_OPEN_SESSION / MBEDTEE_RPC_INVOKE_SESSION /
> + * MBEDTEE_RPC_CLOSE_SESSION).
> + */
> +struct rpc_param {
> + s32 session_id;
> + u32 cmd_id;
> + u32 ret_origin;
> + u32 params_type;
> + union rpc_tee_param params[4];
> + u8 uuid[16];
> + u8 clnt_uuid[16];
> +};
> +
> +/*
> + * REE -> TEE cancellation request (MBEDTEE_RPC_CANCEL).
> + */
> +struct rpc_cancel_req {
> + u32 session_id;
> + u32 cancel_id;
> +};
> +
> +/*
> + * TEE <-> REE supplicant payloads for REEFS and RPMB RPCs.
> + * Only the fixed headers are interpreted in the Linux driver.
> + */
> +/*
> + * Common supplicant command header. Both reefs_cmd and rpmb_cmd embed this
> + * as their first member so the kernel can write a status code through a
> + * single cast to (struct supp_cmd_hdr *) without caring about the full
> + * payload type. The wire layout is identical on every architecture.
> + */
> +struct supp_cmd_hdr {
> + s32 ret;
> + s32 op;
> +};
> +
> +struct reefs_cmd {
> + struct supp_cmd_hdr hdr;
> + s32 flags;
> + s32 fd;
> + u64 len;
> + u8 data[];
> +};
> +
> +struct rpmb_cmd {
> + struct supp_cmd_hdr hdr;
> + u32 nframes;
> + u8 data[];
> +};
> +
> +/*
> + * TEE <-> REE RPC ring buffer header (24 bytes fixed).
> + */
> +struct rpc_ringbuf {
> + u32 wr; /* producer write pointer */
> + u32 rd; /* consumer read pointer */
> + u32 callee_ready; /* callee ready flag */
> + u32 callee_imsic_id; /* RISC-V only: IMSIC local interrupt id */
> + u32 callee_hartid; /* RISC-V only: target hart-id for T2R notification */
> + u32 reserved; /* padding, must be zero */
> + u8 mem[];
> +};
> +
> +/*
> + * Compile-time ABI layout assertions.
> + * These must match the _Static_assert() checks in mbedtee-os rpc/rpc.h.
> + */
> +static_assert(sizeof(struct rpc_cmd) == 32,
> + "rpc_cmd wire size mismatch");
> +static_assert(offsetof(struct rpc_cmd, ret) == 8,
> + "rpc_cmd.ret offset mismatch");
> +static_assert(offsetof(struct rpc_cmd, waiter_id) == 16,
> + "rpc_cmd.waiter_id offset mismatch");
> +static_assert(offsetof(struct rpc_cmd, shm) == 24,
> + "rpc_cmd.shm offset mismatch");
> +static_assert(offsetof(struct rpc_cmd, data) == 32,
> + "rpc_cmd.data offset mismatch");
> +static_assert(sizeof(struct rpc_memref) == 40,
> + "rpc_memref wire size mismatch");
> +static_assert(sizeof(struct rpc_ringbuf) == 24,
> + "rpc_ringbuf header size mismatch");
> +static_assert(sizeof(struct rpc_param) == 208,
> + "rpc_param wire size mismatch");
> +static_assert(sizeof(struct rpc_cancel_req) == 8,
> + "rpc_cancel_req wire size mismatch");
> +
> +#endif /* MBEDTEE_MSG_H */
> diff --git a/drivers/tee/mbedtee/rpc_callee.c b/drivers/tee/mbedtee/rpc_callee.c
> new file mode 100644
> index 0000000..258f8d1
> --- /dev/null
> +++ b/drivers/tee/mbedtee/rpc_callee.c
> @@ -0,0 +1,697 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2020 Xing Loong <xing.xl.loong at gmail.com>
> + * TEE->REE callee-side: handles interrupts from TEE, processes RPC requests.
> + */
> +#include <linux/cpu.h>
> +#include <linux/cpuhotplug.h>
> +#include <linux/cpumask.h>
> +#include <linux/delay.h>
> +#include <linux/errno.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/jiffies.h>
> +#include <linux/ktime.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +#include <linux/tee_drv.h>
> +#include <linux/workqueue.h>
> +
> +#include "mbedtee_drv.h"
> +
> +/* Give up completing a sync RPC if the TEE stops draining its ring. */
> +#define MBEDTEE_RPC_COMPLETE_TIMEOUT (30 * HZ)
> +
> +/*
> + * CPU hotplug state shared across all mbedtee instances (registered once).
> + */
> +static int mbedtee_cpuhp_state = -EINVAL;
> +static unsigned int mbedtee_cpuhp_instances;
> +static DEFINE_MUTEX(mbedtee_cpuhp_mutex);
> +/* rpc_routine() runs on workqueue, re-drains ring on completion */
> +static void rpc_routine(struct work_struct *work);
> +
> +/*
> + * Common CPU-online handler: add the new CPU into the eligible T2R
> + * delivery set and let the transport re-apply affinity.
> + */
> +static int mbedtee_cpu_online(unsigned int cpu, struct hlist_node *node)
> +{
> + struct mbedtee_t2r_ctx *ctx =
> + hlist_entry(node, struct mbedtee_t2r_ctx, hp_node);
> + struct mbedtee_device *mbedtee =
> + container_of(ctx, struct mbedtee_device, t2r);
> + unsigned int target_cpu;
> +
> + if (!ctx->t2r_ring || cpumask_test_cpu(cpu, &ctx->callee_cpus))
> + return 0;
> +
> + cpumask_set_cpu(cpu, &ctx->callee_cpus);
> + target_cpu = cpumask_first(&ctx->callee_cpus);
> +
> + if (mbedtee->rpc_ops && mbedtee->rpc_ops->update_affinity)
> + mbedtee->rpc_ops->update_affinity(mbedtee, target_cpu);
> +
> + return 0;
> +}
> +
> +/*
> + * Common CPU-offline handler: migrates T2R interrupt delivery to another
> + * online CPU when the current callee CPU is being taken offline.
> + *
> + * The transport-specific update_affinity() callback handles the actual
> + * interrupt migration (e.g. irq_set_affinity + callee_hartid update for
> + * RISC-V IMSIC; irq_set_affinity only for ARM - no ring update needed).
> + */
> +static int mbedtee_cpu_offline(unsigned int cpu, struct hlist_node *node)
> +{
> + struct mbedtee_t2r_ctx *ctx =
> + hlist_entry(node, struct mbedtee_t2r_ctx, hp_node);
> + struct mbedtee_device *mbedtee =
> + container_of(ctx, struct mbedtee_device, t2r);
> + unsigned int new_cpu;
> +
> + if (!ctx->t2r_ring || !cpumask_test_cpu(cpu, &ctx->callee_cpus))
> + return 0;
> +
> + /*
> + * Remove the dying CPU from the eligible set. If the set is now
> + * empty (all CPUs going away at once -- highly unlikely but safe),
> + * fall back to CPU 0 which Linux guarantees to be the last offline.
> + */
> + cpumask_clear_cpu(cpu, &ctx->callee_cpus);
> + if (cpumask_empty(&ctx->callee_cpus))
> + cpumask_set_cpu(0, &ctx->callee_cpus);
> +
> + new_cpu = cpumask_first(&ctx->callee_cpus);
> +
> + if (mbedtee->rpc_ops && mbedtee->rpc_ops->update_affinity)
> + mbedtee->rpc_ops->update_affinity(mbedtee, new_cpu);
> + return 0;
> +}
> +
> +static inline size_t t2r_available_size(struct mbedtee_t2r_ctx *ctx)
> +{
> + u32 wr;
> + u32 rd;
> + u32 shm_size = ctx->t2r_ring_sz;
> +
> + /* Pair with producer release store after writing ring payload. */
> + wr = smp_load_acquire(&ctx->t2r_ring->wr);
> + rd = READ_ONCE(ctx->t2r_ring_rd);
> +
> + /* Corrupt indices mean the stream cannot be trusted. */
> + if (wr > shm_size || rd > shm_size)
> + return 0;
> +
> + if (wr >= rd)
> + return wr - rd;
> + return shm_size + wr - rd;
> +}
> +
> +static void t2r_ring_copy(struct mbedtee_t2r_ctx *ctx,
> + void *data, size_t size, u32 rd)
> +{
> + u32 remain;
> + u32 shm_size = ctx->t2r_ring_sz;
> + struct rpc_ringbuf *shm = ctx->t2r_ring;
> +
> + if (rd + size <= shm_size) {
> + memcpy(data, &shm->mem[rd], size);
> + } else {
> + remain = rd + size - shm_size;
> + memcpy(data, &shm->mem[rd], size - remain);
> + memcpy((u8 *)data + size - remain,
> + &shm->mem[0], remain);
> + }
> +}
> +
> +static void t2r_ring_advance(struct mbedtee_t2r_ctx *ctx, size_t size)
> +{
> + u32 rd = READ_ONCE(ctx->t2r_ring_rd);
> + u32 shm_size = ctx->t2r_ring_sz;
> + struct rpc_ringbuf *shm = ctx->t2r_ring;
> +
> + if (rd + size > shm_size)
> + rd = rd + size - shm_size;
> + else
> + rd += size;
> +
> + WRITE_ONCE(ctx->t2r_ring_rd, rd);
> + /* Publish updated consumer index after command parsing is complete. */
> + smp_store_release(&shm->rd, rd);
> +}
> +
> +/*
> + * Read and consume @size bytes from the TEE-to-REE ring buffer.
> + * Must be called with ctx->ring_lock held.
> + */
> +static void t2r_ring_read(struct mbedtee_t2r_ctx *ctx,
> + void *data, size_t size)
> +{
> + t2r_ring_copy(ctx, data, size, READ_ONCE(ctx->t2r_ring_rd));
> + t2r_ring_advance(ctx, size);
> +}
> +
> +static bool rpc_queue_complete_only(struct mbedtee_t2r_ctx *ctx,
> + u64 waiter_id)
> +{
> + /* Called with ctx->ring_lock held. */
> + if (ctx->complete_work_pending)
> + return false;
> +
> + ctx->complete_work_pending = true;
> + ctx->complete_work.waiter_id = waiter_id;
> + queue_work(ctx->rpc_wq, &ctx->complete_work.work);
> +
> + return true;
> +}
> +
> +/*
> + * Try to pick the next RPC command from the ring buffer.
> + *
> + * For asynchronous RPCs the data payload follows the cmd header in the
> + * ring. If the payload has not fully arrived yet the cmd header is still
> + * consumed (it was already read) but the entry is marked incomplete so
> + * that the next IRQ resumes reading the payload instead of re-reading
> + * a header.
> + *
> + * For synchronous RPCs (waiter_id != 0) the work descriptor is allocated
> + * BEFORE the ring header is consumed. This guarantees that if the
> + * allocator returns NULL the ring entry is left intact so the IRQ
> + * handler will retry on the next wake-up rather than leaving a TEE
> + * thread blocked with no response.
> + *
> + * Returns a work descriptor on success, or NULL when no complete entry
> + * is available.
> + */
> +static struct rpc_work *rpc_pick_next(struct mbedtee_device *mbedtee,
> + struct mbedtee_t2r_ctx *ctx, struct rpc_work *c)
> +{
> + struct rpc_cmd cmd;
> + void (*func)(struct mbedtee_device *mbedtee, void *data, size_t size);
> + struct rpc_work *new_work = NULL;
> + resource_size_t off;
> + phys_addr_t shm_phys;
> + u64 shm_wire;
> +
> + /* Resume reading payload of a previously incomplete async RPC */
> + if (ctx->pending_async) {
> + if (t2r_available_size(ctx) < ctx->pending_size)
> + return NULL;
> + ctx->pending_async = false;
> + t2r_ring_read(ctx, c->data, ctx->pending_size);
> + c->func = ctx->pending_func;
> + c->size = ctx->pending_size;
> + c->waiter_id = 0;
> + return c;
> + }
> +
> + if (t2r_available_size(ctx) < sizeof(cmd))
> + return NULL;
> +
> + /*
> + * Peek at the header without advancing the ring pointer.
> + * For sync RPCs we must pre-allocate before consuming the entry.
> + */
> + memset(&cmd, 0, sizeof(cmd));
> + t2r_ring_copy(ctx, &cmd, sizeof(cmd), READ_ONCE(ctx->t2r_ring_rd));
> +
> + if (cmd.id >= MBEDTEE_RPC_MAX)
> + goto skip;
> +
> + func = ctx->rpc_handlers[cmd.id];
> + if (!func)
> + goto skip;
> +
> + /*
> + * The TEE sends COMPLETE_REE asynchronously and the supplicant
> + * commands (REEFS/RPMB) synchronously. Reject inverted usage so
> + * that blocking supplicant handlers can never run inline in IRQ
> + * context while the ring lock is held.
> + */
> + switch (cmd.id) {
> + case MBEDTEE_RPC_COMPLETE_REE:
> + if (cmd.waiter_id != 0)
> + goto skip;
> + break;
> + case MBEDTEE_RPC_REETIME:
> + case MBEDTEE_RPC_REEFS:
> + case MBEDTEE_RPC_RPMB:
> + if (cmd.waiter_id == 0)
> + goto skip;
> + if ((cmd.id == MBEDTEE_RPC_REEFS ||
> + cmd.id == MBEDTEE_RPC_RPMB) &&
> + cmd.size < sizeof(struct supp_cmd_hdr))
> + goto skip;
> + break;
> + default:
> + break;
> + }
> +
> + if (cmd.waiter_id == 0) {
> + /* Async RPC: payload follows header in the ring */
> + if (cmd.size > sizeof(ctx->rpc_data))
> + goto skip;
> +
> + /* Consume the header now that we know it is valid */
> + t2r_ring_advance(ctx, sizeof(cmd));
> +
> + if (t2r_available_size(ctx) < cmd.size) {
> + /* Mark as incomplete, resume on next iteration */
> + ctx->pending_async = true;
> + ctx->pending_size = cmd.size;
> + ctx->pending_func = func;
> + return NULL;
> + }
> +
> + t2r_ring_read(ctx, c->data, cmd.size);
> + } else {
> + /* Sync RPC: data lives in the shared memory region */
> + shm_wire = cmd.shm;
> + shm_phys = (phys_addr_t)shm_wire;
> + if ((u64)shm_phys != shm_wire)
> + goto skip;
> +
> + if (shm_phys < ctx->t2r_shm_phys)
> + goto skip;
> +
> + off = shm_phys - ctx->t2r_shm_phys;
> + if (cmd.size == 0 || cmd.size > ctx->t2r_shm_sz)
> + goto skip;
> +
> + if (off > ctx->t2r_shm_sz - cmd.size)
> + goto skip;
> +
> + new_work = kzalloc_obj(*new_work, GFP_ATOMIC);
> + if (!new_work) {
> + /*
> + * Leave the header in place. The TEE re-notifies when
> + * its sync RPC retry timer fires, so this entry is
> + * retried on the next IRQ instead of being lost.
> + */
> + return NULL;
> + }
> +
> + t2r_ring_advance(ctx, sizeof(cmd));
> +
> + c = new_work;
> + c->mbedtee = mbedtee;
> + c->data = ctx->t2r_shm + off;
> + }
> +
> + c->func = func;
> + c->waiter_id = cmd.waiter_id;
> + c->size = cmd.size;
> +
> + return c;
> +
> +skip:
> + /*
> + * If this was a sync RPC (waiter_id != 0) we must notify the TEE
> + * thread so it does not wait forever. Defer the completion fastcall
> + * to process context because transport implementations may sleep.
> + * If the single deferred-completion slot is already in use, leave the
> + * header in place and retry after the pending completion has drained.
> + */
> + if (cmd.waiter_id != 0 && !rpc_queue_complete_only(ctx, cmd.waiter_id))
> + return NULL;
> +
> + /*
> + * Bad or unhandled entry: consume header plus any inline payload
> + * (async RPC payloads follow the header in the ring) to keep the
> + * ring moving. For sync RPCs payload is in t2r_shm, not the ring.
> + *
> + * An async payload must fit the ring and be fully published;
> + * otherwise the stream cannot be framed and no later entry can be
> + * trusted, so drop the whole pending snapshot instead of moving
> + * the reader past the producer.
> + */
> + if (cmd.waiter_id == 0 &&
> + (cmd.size > ctx->t2r_ring_sz - sizeof(cmd) ||
> + t2r_available_size(ctx) < sizeof(cmd) + cmd.size)) {
> + t2r_ring_advance(ctx, t2r_available_size(ctx));
> + return NULL;
> + }
> +
> + t2r_ring_advance(ctx, sizeof(cmd) + (cmd.waiter_id ? 0 : cmd.size));
> +
> + return NULL;
> +}
> +
> +static void rpc_drain_ring(struct mbedtee_device *mbedtee)
> +{
> + struct mbedtee_t2r_ctx *ctx = &mbedtee->t2r;
> + struct rpc_work rw = {}, *c = NULL;
> + unsigned long flags;
> +
> + if (!ctx->t2r_ring)
> + return;
> +
> + spin_lock_irqsave(&ctx->ring_lock, flags);
> + while (READ_ONCE(ctx->t2r_ring_rd) !=
> + /* Pair with producer store-release after ring write. */
> + smp_load_acquire(&ctx->t2r_ring->wr)) {
> + rw.data = ctx->rpc_data;
> + c = rpc_pick_next(mbedtee, ctx, &rw);
> + if (!c)
> + break;
> +
> + if (c->waiter_id == 0) {
> + c->func(mbedtee, c->data, c->size);
> + } else {
> + INIT_WORK(&c->work, rpc_routine);
> + queue_work(ctx->rpc_wq, &c->work);
> + }
> + }
> + spin_unlock_irqrestore(&ctx->ring_lock, flags);
> +}
> +
> +static void rpc_routine(struct work_struct *work)
> +{
> + struct rpc_work *c = container_of(work, struct rpc_work, work);
> + struct mbedtee_t2r_ctx *ctx = &c->mbedtee->t2r;
> + unsigned long deadline = jiffies + MBEDTEE_RPC_COMPLETE_TIMEOUT;
> + unsigned long flags;
> + long ret;
> +
> + if (!c->complete_only)
> + c->func(c->mbedtee, c->data, c->size);
> +
> + /*
> + * COMPLETE_TEE must reach the TEE thread that issued the sync RPC.
> + * On RISC-V the notification uses a shared ring buffer that may be
> + * transiently full when many RPCs are in flight concurrently.
> + * Keep retrying rather than silently dropping the completion, which
> + * would leave the TEE thread blocked in rpc_call_sync forever.
> + * On ARM the fastcall is a direct SMC so -ENOSPC never occurs.
> + * Stop retrying at teardown or when the deadline passes so a dead
> + * TEE cannot hang destroy_workqueue().
> + */
> + do {
> + if (READ_ONCE(ctx->stopping))
> + break;
> + ret = mbedtee_rpc_fastcall(c->mbedtee, MBEDTEE_RPC_COMPLETE_TEE,
> + (unsigned long)c->waiter_id, 0, 0);
> + if (ret != -ENOSPC && ret != -ENOMEM)
> + break;
> + if (time_after_eq(jiffies, deadline)) {
> + dev_err(c->mbedtee->dev,
> + "COMPLETE_TEE for waiter %llu timed out\n",
> + c->waiter_id);
> + break;
> + }
> + cond_resched();
> + } while (1);
> +
> + if (c != &ctx->complete_work) {
> + kfree(c);
> + return;
> + }
> +
> + /* complete_work_pending is always accessed under ring_lock. */
> + spin_lock_irqsave(&ctx->ring_lock, flags);
> + ctx->complete_work_pending = false;
> + spin_unlock_irqrestore(&ctx->ring_lock, flags);
> + if (!READ_ONCE(ctx->stopping))
> + rpc_drain_ring(c->mbedtee);
> +}
> +
> +/*
> + * Hard IRQ handler -- drains the TEE-to-REE ring buffer.
> + *
> + * Asynchronous RPCs (waiter_id == 0) are handled inline since all async
> + * handlers (complete(), ktime_get_real_ts64()) are non-blocking.
> + *
> + * Synchronous RPCs (waiter_id != 0) may block waiting for the
> + * tee-supplicant, so they are dispatched to a workqueue.
> + */
> +irqreturn_t mbedtee_rpc_irq_handler(int irq, void *dev_id)
> +{
> + struct mbedtee_device *mbedtee = dev_id;
> +
> + if (!mbedtee)
> + return IRQ_NONE;
> +
> + rpc_drain_ring(mbedtee);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static void mbedtee_rpc_complete(struct mbedtee_device *mbedtee,
> + void *data, size_t size)
> +{
> + u64 waiter_id;
> +
> + if (size < sizeof(waiter_id))
> + return;
> +
> + memcpy(&waiter_id, data, sizeof(waiter_id));
> + if (!waiter_id)
> + return;
> +
> + mbedtee_rpc_complete_call(mbedtee, waiter_id);
> +}
> +
> +static void mbedtee_ree_time(struct mbedtee_device *mbedtee,
> + void *data, size_t size)
> +{
> + struct timespec64 *ts = data;
> +
> + if (size < sizeof(*ts))
> + return;
> +
> + ktime_get_real_ts64(ts);
> +}
> +
> +static void mbedtee_reefs_supp(struct mbedtee_device *mbedtee,
> + void *data, size_t size)
> +{
> + mbedtee_supp_handler(mbedtee, MBEDTEE_SUPP_REEFS, data, size);
> +}
> +
> +static void mbedtee_rpmb_supp(struct mbedtee_device *mbedtee,
> + void *data, size_t size)
> +{
> + mbedtee_supp_handler(mbedtee, MBEDTEE_SUPP_RPMB, data, size);
> +}
> +
> +static void mbedtee_register_rpc(struct mbedtee_device *mbedtee,
> + u32 id, void (*func)(struct mbedtee_device *mbedtee,
> + void *data, size_t size))
> +{
> + struct mbedtee_t2r_ctx *ctx = &mbedtee->t2r;
> +
> + if (WARN_ON(id >= MBEDTEE_RPC_MAX || !func))
> + return;
> +
> + ctx->rpc_handlers[id] = func;
> +}
> +
> +int mbedtee_rpc_init(struct mbedtee_device *mbedtee)
> +{
> + struct mbedtee_t2r_ctx *ctx = &mbedtee->t2r;
> + struct device_node *node = mbedtee->dev->of_node;
> + struct resource res;
> + bool cpuhp_state_created = false;
> + int ret;
> +
> + memset(ctx, 0, sizeof(*ctx));
> + spin_lock_init(&ctx->ring_lock);
> + mbedtee->rpc_ops = mbedtee_get_rpc_transport_ops();
> + if (!mbedtee->rpc_ops)
> + return -EIO;
> +
> + ret = mbedtee_get_resource(node, "t2r-ring", &res);
> + if (ret) {
> + dev_err(mbedtee->dev, "t2r-ring not found in DT\n");
> + return ret;
> + }
> +
> + ctx->t2r_ring = memremap(res.start, resource_size(&res),
> + MEMREMAP_WB);
> + if (!ctx->t2r_ring) {
> + dev_err(mbedtee->dev, "failed to map t2r ring\n");
> + return -ENOMEM;
> + }
> + if (resource_size(&res) <= sizeof(struct rpc_ringbuf)) {
> + dev_err(mbedtee->dev, "t2r-ring too small\n");
> + memunmap(ctx->t2r_ring);
> + ctx->t2r_ring = NULL;
> + return -EINVAL;
> + }
> + ctx->t2r_ring_sz = resource_size(&res) - sizeof(struct rpc_ringbuf);
> + /* Observe latest producer index only after ring metadata is visible. */
> + WRITE_ONCE(ctx->t2r_ring_rd, smp_load_acquire(&ctx->t2r_ring->rd));
> +
> + dev_dbg(mbedtee->dev, "t2r-ring %pa\n", &res.start);
> +
> + ret = mbedtee_get_resource(node, "t2r-shm", &res);
> + if (ret) {
> + dev_err(mbedtee->dev, "t2r-shm not found in DT\n");
> + goto err_ring;
> + }
> +
> + ctx->t2r_shm_phys = res.start;
> + ctx->t2r_shm_sz = resource_size(&res);
> + ctx->t2r_shm = memremap(res.start, ctx->t2r_shm_sz,
> + MEMREMAP_WB);
> + if (!ctx->t2r_shm) {
> + dev_err(mbedtee->dev, "failed to map t2r shm\n");
> + ret = -ENOMEM;
> + goto err_ring;
> + }
> +
> + dev_dbg(mbedtee->dev, "t2r-shm %pa\n", &res.start);
> +
> + ctx->rpc_wq = alloc_workqueue("mbedtee-rpc", WQ_UNBOUND, 0);
> + if (!ctx->rpc_wq) {
> + dev_err(mbedtee->dev, "failed to create rpc workqueue\n");
> + ret = -ENOMEM;
> + goto err_shm;
> + }
> +
> + ctx->complete_work.mbedtee = mbedtee;
> + ctx->complete_work.complete_only = true;
> + INIT_WORK(&ctx->complete_work.work, rpc_routine);
> +
> + mbedtee_register_rpc(mbedtee, MBEDTEE_RPC_COMPLETE_REE, mbedtee_rpc_complete);
> + mbedtee_register_rpc(mbedtee, MBEDTEE_RPC_REETIME, mbedtee_ree_time);
> + mbedtee_register_rpc(mbedtee, MBEDTEE_RPC_REEFS, mbedtee_reefs_supp);
> + mbedtee_register_rpc(mbedtee, MBEDTEE_RPC_RPMB, mbedtee_rpmb_supp);
> +
> + /*
> + * Register cpuhp instance BEFORE enabling interrupts so that
> + * T2R delivery migration is in place before the first IRQ fires.
> + */
> + mutex_lock(&mbedtee_cpuhp_mutex);
> + if (mbedtee_cpuhp_state < 0) {
> + mbedtee_cpuhp_state =
> + cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
> + "tee/mbedtee:rpc-callee",
> + mbedtee_cpu_online,
> + mbedtee_cpu_offline);
> + if (mbedtee_cpuhp_state < 0) {
> + ret = mbedtee_cpuhp_state;
> + mutex_unlock(&mbedtee_cpuhp_mutex);
> + goto err_wq;
> + }
> + cpuhp_state_created = true;
> + }
> +
> + ret = cpuhp_state_add_instance(mbedtee_cpuhp_state, &ctx->hp_node);
> + if (!ret) {
> + mbedtee_cpuhp_instances++;
> + ctx->cpuhp_added = true;
> + } else if (cpuhp_state_created) {
> + cpuhp_remove_multi_state(mbedtee_cpuhp_state);
> + mbedtee_cpuhp_state = -EINVAL;
> + }
> + mutex_unlock(&mbedtee_cpuhp_mutex);
> + if (ret != 0)
> + goto err_wq;
> +
> + ret = mbedtee->rpc_ops->init(mbedtee, ctx->t2r_ring,
> + mbedtee_rpc_irq_handler);
> + if (ret != 0)
> + goto err_cpuhp;
> +
> + /* Signal the TEE that the REE callee is ready to receive. */
> + smp_store_release(&ctx->t2r_ring->callee_ready, true);
> +
> + return 0;
> +
> +err_cpuhp:
> + mutex_lock(&mbedtee_cpuhp_mutex);
> + if (mbedtee_cpuhp_state >= 0 && ctx->cpuhp_added) {
> + cpuhp_state_remove_instance_nocalls(mbedtee_cpuhp_state,
> + &ctx->hp_node);
> + ctx->cpuhp_added = false;
> + if (mbedtee_cpuhp_instances)
> + mbedtee_cpuhp_instances--;
> + if (!mbedtee_cpuhp_instances) {
> + cpuhp_remove_multi_state(mbedtee_cpuhp_state);
> + mbedtee_cpuhp_state = -EINVAL;
> + }
> + }
> + mutex_unlock(&mbedtee_cpuhp_mutex);
> +err_wq:
> + destroy_workqueue(ctx->rpc_wq);
> + ctx->rpc_wq = NULL;
> +err_shm:
> + memunmap(ctx->t2r_shm);
> + ctx->t2r_shm = NULL;
> +err_ring:
> + memunmap(ctx->t2r_ring);
> + ctx->t2r_ring = NULL;
> + return ret;
> +}
> +
> +void mbedtee_rpc_uninit(struct mbedtee_device *mbedtee)
> +{
> + struct mbedtee_t2r_ctx *ctx;
> +
> + if (!mbedtee)
> + return;
> +
> + ctx = &mbedtee->t2r;
> + mbedtee_rpc_stop(mbedtee);
> +
> + /* Transport and workqueue resources can now be torn down safely. */
> +
> + mutex_lock(&mbedtee_cpuhp_mutex);
> + if (mbedtee_cpuhp_state >= 0 && ctx->cpuhp_added) {
> + cpuhp_state_remove_instance_nocalls(mbedtee_cpuhp_state,
> + &ctx->hp_node);
> + ctx->cpuhp_added = false;
> + if (mbedtee_cpuhp_instances)
> + mbedtee_cpuhp_instances--;
> + if (!mbedtee_cpuhp_instances) {
> + cpuhp_remove_multi_state(mbedtee_cpuhp_state);
> + mbedtee_cpuhp_state = -EINVAL;
> + }
> + }
> + mutex_unlock(&mbedtee_cpuhp_mutex);
> +
> + if (mbedtee->rpc_ops)
> + mbedtee->rpc_ops->uninit(mbedtee);
> +
> + if (ctx->rpc_wq) {
> + destroy_workqueue(ctx->rpc_wq);
> + ctx->rpc_wq = NULL;
> + }
> +
> + if (ctx->t2r_shm) {
> + memunmap(ctx->t2r_shm);
> + ctx->t2r_shm = NULL;
> + }
> +
> + if (ctx->t2r_ring) {
> + memunmap(ctx->t2r_ring);
> + ctx->t2r_ring = NULL;
> + }
> +}
> +
> +/*
> + * Quiesce all RPC activity: reject new submissions and wake every waiter.
> + * Idempotent -- called directly from remove() and again from rpc_uninit()
> + * (which the probe error path reaches without a prior stop).
> + */
> +void mbedtee_rpc_stop(struct mbedtee_device *mbedtee)
> +{
> + struct mbedtee_t2r_ctx *ctx;
> +
> + if (!mbedtee)
> + return;
> +
> + ctx = &mbedtee->t2r;
> + /* Stop advertising the REE callee before interrupt teardown. */
> + if (ctx->t2r_ring)
> + WRITE_ONCE(ctx->t2r_ring->callee_ready, false);
> + WRITE_ONCE(ctx->stopping, true);
> + mbedtee_r2t_stop(mbedtee);
> + mbedtee_supp_abort_all(&mbedtee->supp);
> + mbedtee_rpc_calls_abort(mbedtee);
> +}
> diff --git a/drivers/tee/mbedtee/rpc_callee_arm.c b/drivers/tee/mbedtee/rpc_callee_arm.c
> new file mode 100644
> index 0000000..871bba5
> --- /dev/null
> +++ b/drivers/tee/mbedtee/rpc_callee_arm.c
> @@ -0,0 +1,91 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2020 Xing Loong <xing.xl.loong at gmail.com>
> + * ARM/ARM64 GIC transport for the TEE->REE RPC callee.
> + *
> + * On ARM/ARM64 the TEE raises a rising-edge software-generated interrupt
> + * described by the "interrupts" property of the mbedtee DT node. This file
> + * obtains that virq via of_irq_get() and registers the hard IRQ handler
> + * supplied by the core callee layer.
> + */
> +#include <linux/interrupt.h>
> +#include <linux/cpu.h>
> +#include <linux/of.h>
> +#include <linux/of_irq.h>
> +
> +#include "mbedtee_drv.h"
> +
> +static int arm_transport_init(struct mbedtee_device *mbedtee,
> + struct rpc_ringbuf *ring, irq_handler_t handler)
> +{
> + struct mbedtee_t2r_ctx *ctx = &mbedtee->t2r;
> + struct mbedtee_rpc_transport_ctx *tctx = &mbedtee->transport;
> + int ret;
> +
> + tctx->rpc_notify_virq = of_irq_get(mbedtee->dev->of_node, 0);
> + if (tctx->rpc_notify_virq <= 0)
> + return tctx->rpc_notify_virq ? tctx->rpc_notify_virq : -ENODEV;
> +
> + ret = request_irq(tctx->rpc_notify_virq, handler,
> + 0, "mbedtee-rpc", mbedtee);
> + if (ret) {
> + dev_warn(mbedtee->dev, "request_irq %d failed: %d\n",
> + tctx->rpc_notify_virq, ret);
> + tctx->rpc_notify_virq = 0;
> + return ret;
> + }
> +
> + /*
> + * Spread the T2R SPI across all online CPUs in Linux.
> + * The TEE needs no CPU information from Linux: it broadcasts
> + * via GIC hardware (GICv2 ITARGETS=0xFF / GICv3 IROUTER.IRM=1).
> + */
> + cpumask_copy(&ctx->callee_cpus, cpu_online_mask);
> + if (irq_set_affinity(tctx->rpc_notify_virq, &ctx->callee_cpus))
> + dev_warn(mbedtee->dev, "irq_set_affinity failed\n");
> +
> + dev_dbg(mbedtee->dev, "t2r-irq %d\n", tctx->rpc_notify_virq);
> + return 0;
> +}
> +
> +static void arm_transport_uninit(struct mbedtee_device *mbedtee)
> +{
> + struct mbedtee_rpc_transport_ctx *tctx = &mbedtee->transport;
> +
> + if (tctx->rpc_notify_virq > 0) {
> + free_irq(tctx->rpc_notify_virq, mbedtee);
> + tctx->rpc_notify_virq = 0;
> + }
> +}
> +
> +/*
> + * ARM T2R uses a GIC SPI: the TEE broadcasts it via GIC hardware
> + * (GICv2 ITARGETS=0xFF or GICv3 IROUTER.IRM=1) to any alive CPU.
> + * TrustZone shares physical CPUs -- no ring update is ever needed.
> + *
> + * @new_cpu is ignored: the IRQ is re-affined to ctx->callee_cpus which
> + * the core callee layer keeps in sync (dying CPU already removed before
> + * this callback is invoked, so the mask is always accurate).
> + */
> +static int arm_update_affinity(struct mbedtee_device *mbedtee,
> + unsigned int new_cpu)
> +{
> + struct mbedtee_rpc_transport_ctx *tctx = &mbedtee->transport;
> +
> + if (tctx->rpc_notify_virq > 0 &&
> + irq_set_affinity(tctx->rpc_notify_virq, &mbedtee->t2r.callee_cpus))
> + dev_warn(mbedtee->dev, "irq_set_affinity failed\n");
> +
> + return 0;
> +}
> +
> +static const struct rpc_transport_ops arm_transport_ops = {
> + .init = arm_transport_init,
> + .uninit = arm_transport_uninit,
> + .update_affinity = arm_update_affinity,
> +};
> +
> +const struct rpc_transport_ops *mbedtee_get_rpc_transport_ops(void)
> +{
> + return &arm_transport_ops;
> +}
> diff --git a/drivers/tee/mbedtee/rpc_callee_riscv.c b/drivers/tee/mbedtee/rpc_callee_riscv.c
> new file mode 100644
> index 0000000..7ac0f8e
> --- /dev/null
> +++ b/drivers/tee/mbedtee/rpc_callee_riscv.c
> @@ -0,0 +1,203 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2025 Xing Loong <xing.xl.loong at gmail.com>
> + * RISC-V MSI transport for the TEE->REE RPC callee.
> + *
> + * On RISC-V the TEE wakes the REE by writing a Message Signalled Interrupt
> + * into the target hart's IMSIC (Incoming MSI Controller). This file allocates
> + * one platform MSI from the DT-provided MSI parent and registers the hard IRQ
> + * handler supplied by the core callee layer.
> + *
> + * CPU hotplug: the common mbedtee_cpu_offline() callback in rpc_callee.c
> + * detects when the callee CPU goes offline and calls riscv_update_affinity()
> + * to migrate the MSI to another online CPU.
> + */
> +#include <linux/interrupt.h>
> +#include <linux/msi.h>
> +#include <linux/of_irq.h>
> +#include <linux/smp.h>
> +
> +#include "mbedtee_drv.h"
> +
> +static int mbedtee_ring_set_hartid(struct mbedtee_device *mbedtee,
> + struct rpc_ringbuf *ring,
> + unsigned int cpu)
> +{
> + long hartid = cpuid_to_hartid_map(cpu);
> +
> + if (hartid < 0) {
> + dev_err(mbedtee->dev, "CPU%u has no valid hart-id\n", cpu);
> + return -ERANGE;
> + }
> +
> + WRITE_ONCE(ring->callee_hartid, (u32)hartid);
> + return 0;
> +}
> +
> +static void mbedtee_rpc_write_msi_msg(struct msi_desc *desc_msi,
> + struct msi_msg *msg)
> +{
> + struct mbedtee_device *mbedtee = dev_get_drvdata(desc_msi->dev);
> +
> + if (mbedtee)
> + mbedtee->transport.rpc_msi_msg = *msg;
> +}
> +
> +static int riscv_transport_init(struct mbedtee_device *mbedtee,
> + struct rpc_ringbuf *ring, irq_handler_t handler)
> +{
> + struct mbedtee_t2r_ctx *ctx = &mbedtee->t2r;
> + const struct cpumask *eff;
> + struct mbedtee_rpc_transport_ctx *tctx = &mbedtee->transport;
> + unsigned int cpu;
> + struct device *dev = mbedtee->dev;
> + int virq;
> + int ret;
> +
> + /*
> + * Set a bootstrap callee_hartid (hart 0) so the TEE can poll
> + * even if MSI setup fails below.
> + */
> + ret = mbedtee_ring_set_hartid(mbedtee, ring, 0);
> + if (ret)
> + return ret;
> +
> + dev_set_drvdata(dev, mbedtee);
> +
> + /*
> + * The MSI domain of an OF device is resolved only once, when the
> + * platform device is created (of_msi_configure() in of/platform.c).
> + * mbedtee's MSI parent is the IMSIC, whose MSI domain is created
> + * later, when the IMSIC builtin_platform_driver probes -- typically
> + * after this device has already been created with a NULL msi.domain.
> + *
> + * Deferred probing alone cannot recover from this: the driver core
> + * re-runs probe() but never re-runs of_msi_configure(), so the stale
> + * NULL domain would persist across every retry. Re-resolve it here
> + * and defer until the IMSIC driver is up. This mirrors the RISC-V
> + * APLIC/IOMMU platform-MSI drivers.
> + */
> + if (!dev_get_msi_domain(dev)) {
> + of_msi_configure(dev, dev->of_node);
> +
> + if (!dev_get_msi_domain(dev))
> + return -EPROBE_DEFER;
> + }
> +
> + ret = platform_device_msi_init_and_alloc_irqs(dev, 1,
> + mbedtee_rpc_write_msi_msg);
> + if (ret) {
> + dev_err(mbedtee->dev, "MSI alloc failed: %d\n", ret);
> + return ret;
> + }
> +
> + virq = msi_get_virq(dev, 0);
> + if (virq <= 0) {
> + dev_err(mbedtee->dev, "no MSI virq\n");
> + ret = -ENOENT;
> + goto err_msi;
> + }
> +
> + ret = request_irq(virq, handler, 0, "mbedtee-rpc", mbedtee);
> + if (ret) {
> + dev_err(mbedtee->dev, "request_irq %d failed: %d\n", virq, ret);
> + goto err_msi;
> + }
> +
> + eff = irq_get_effective_affinity_mask(virq);
> + cpu = eff ? cpumask_first(eff) : 0;
> +
> + dev_dbg(mbedtee->dev, "MSI addr 0x%x%08x data %d virq %d hart %ld\n",
> + tctx->rpc_msi_msg.address_hi, tctx->rpc_msi_msg.address_lo,
> + tctx->rpc_msi_msg.data, virq, cpuid_to_hartid_map(cpu));
> +
> + /* Inform TEE of the IMSIC identity used for T2R notifications. */
> + ret = mbedtee_ring_set_hartid(mbedtee, ring, cpu);
> + if (ret)
> + goto err_irq;
> + /* Ensure callee_hartid is visible before advertising MSI interrupt ID. */
> + smp_store_release(&ring->callee_imsic_id, tctx->rpc_msi_msg.data);
> +
> + /* Track the active callee CPU for hotplug migration. */
> + ctx->callee_virq = virq;
> + cpumask_set_cpu(cpu, &ctx->callee_cpus);
> +
> + return 0;
> +
> +err_irq:
> + free_irq(virq, mbedtee);
> +
> +err_msi:
> + platform_device_msi_free_irqs_all(dev);
> + return ret;
> +}
> +
> +static void riscv_transport_uninit(struct mbedtee_device *mbedtee)
> +{
> + struct mbedtee_t2r_ctx *ctx = &mbedtee->t2r;
> + int virq;
> +
> + virq = ctx->callee_virq;
> + ctx->callee_virq = 0;
> + if (virq > 0)
> + free_irq(virq, mbedtee);
> +
> + platform_device_msi_free_irqs_all(mbedtee->dev);
> +}
> +
> +/*
> + * Migrate the IMSIC MSI delivery to @new_cpu.
> + *
> + * Ordering guarantee for the TEE reader:
> + * 1. Clear callee_imsic_id to 0 -- TEE skips IMSIC path while we migrate.
> + * 2. Call irq_set_affinity() -- triggers mbedtee_rpc_write_msi_msg() which
> + * updates tctx->rpc_msi_msg with the new IMSIC identity.
> + * 3. Update callee_hartid (WRITE_ONCE inside mbedtee_ring_set_hartid());
> + * no explicit barrier needed here since the release store on
> + * callee_imsic_id in step 4 provides the ordering.
> + * 4. Publish new callee_imsic_id with smp_store_release -- TEE's
> + * smp_load_acquire on callee_imsic_id pairs with this store.
> + */
> +static int riscv_update_affinity(struct mbedtee_device *mbedtee,
> + unsigned int new_cpu)
> +{
> + struct mbedtee_t2r_ctx *ctx = &mbedtee->t2r;
> + struct mbedtee_rpc_transport_ctx *tctx = &mbedtee->transport;
> + struct rpc_ringbuf *ring = ctx->t2r_ring;
> + int virq = ctx->callee_virq;
> +
> + if (!virq)
> + return -ENODEV;
> +
> + /* Step 1: prevent TEE from using the stale IMSIC identity. */
> + smp_store_release(&ring->callee_imsic_id, 0);
> +
> + /* Step 2: retarget the MSI; write_msi_msg callback updates rpc_msi_msg. */
> + if (irq_set_affinity(virq, cpumask_of(new_cpu))) {
> + dev_warn(mbedtee->dev, "irq_set_affinity to CPU%u failed\n",
> + new_cpu);
> + return -EIO;
> + }
> +
> + /* Step 3: update callee_hartid. */
> + if (mbedtee_ring_set_hartid(mbedtee, ring, new_cpu))
> + return -ERANGE;
> +
> + /* Step 4: publish new IMSIC id with release barrier. */
> + smp_store_release(&ring->callee_imsic_id, tctx->rpc_msi_msg.data);
> +
> + dev_dbg(mbedtee->dev, "T2R callee migrated to CPU%u (hart %ld)\n",
> + new_cpu, cpuid_to_hartid_map(new_cpu));
> + return 0;
> +}
> +
> +static const struct rpc_transport_ops riscv_transport_ops = {
> + .init = riscv_transport_init,
> + .uninit = riscv_transport_uninit,
> + .update_affinity = riscv_update_affinity,
> +};
> +
> +const struct rpc_transport_ops *mbedtee_get_rpc_transport_ops(void)
> +{
> + return &riscv_transport_ops;
> +}
> diff --git a/drivers/tee/mbedtee/rpc_caller.c b/drivers/tee/mbedtee/rpc_caller.c
> new file mode 100644
> index 0000000..6aeb07c
> --- /dev/null
> +++ b/drivers/tee/mbedtee/rpc_caller.c
> @@ -0,0 +1,697 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2020 Xing Loong <xing.xl.loong at gmail.com>
> + * REE->TEE session management and yield-call interface.
> + */
> +#include <linux/mm.h>
> +#include <linux/errno.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/refcount.h>
> +#include "mbedtee_drv.h"
> +
> +#define MBEDTEE_RPC_CALL_ACTIVE 0
> +#define MBEDTEE_RPC_CALL_DONE 1
> +#define MBEDTEE_RPC_CALL_INTERRUPTED 2
> +#define MBEDTEE_RPC_CALL_ABORTED 3
> +
> +static void mbedtee_rpc_call_put(struct mbedtee_rpc_call *call)
> +{
> + if (refcount_dec_and_test(&call->refs))
> + kfree(call);
> +}
> +
> +int mbedtee_rpc_call_alloc(struct mbedtee_device *mbedtee,
> + size_t payload_size, struct mbedtee_rpc_call **call)
> +{
> + struct mbedtee_rpc_call *rcall;
> + unsigned long rpc_index;
> + int ret;
> +
> + if (sizeof(*rcall) + payload_size > PAGE_SIZE)
> + return -E2BIG;
> +
> + rcall = kzalloc(sizeof(*rcall) + payload_size, GFP_KERNEL);
> + if (!rcall)
> + return -ENOMEM;
> +
> + init_completion(&rcall->c);
> + rcall->state = MBEDTEE_RPC_CALL_ACTIVE;
> + /* One reference for the caller, one for the XArray entry. */
> + refcount_set(&rcall->refs, 2);
> + rcall->rpc.size = payload_size;
> + rcall->rpc.ret = -EOPNOTSUPP;
> + rcall->rpc_phys = mbedtee_virt_to_phys(&rcall->rpc);
> +
> + do {
> + rpc_index = atomic_long_inc_return(&mbedtee->rpc_call_seq);
> + } while (rpc_index == 0);
> +
> + mutex_lock(&mbedtee->rpc_calls_mutex);
> + if (mbedtee->stopping) {
> + mutex_unlock(&mbedtee->rpc_calls_mutex);
> + kfree(rcall);
> + return -ESHUTDOWN;
> + }
> + ret = xa_insert_irq(&mbedtee->rpc_calls, rpc_index, rcall, GFP_KERNEL);
> + mutex_unlock(&mbedtee->rpc_calls_mutex);
> + if (ret != 0) {
> + kfree(rcall);
> + return ret;
> + }
> +
> + rcall->rpc.waiter_id = rpc_index;
> + *call = rcall;
> +
> + return 0;
> +}
> +
> +void mbedtee_rpc_call_free(struct mbedtee_device *mbedtee,
> + struct mbedtee_rpc_call *call)
> +{
> + unsigned long flags;
> + unsigned long rpc_index;
> + bool drop_remote = false;
> +
> + if (!call)
> + return;
> +
> + rpc_index = (unsigned long)call->rpc.waiter_id;
> +
> + /*
> + * Interrupted calls remain reachable by the TEE, while aborted calls
> + * retain a quarantined remote reference. In both cases only release the
> + * caller reference here.
> + */
> + xa_lock_irqsave(&mbedtee->rpc_calls, flags);
> + if (call->state != MBEDTEE_RPC_CALL_INTERRUPTED &&
> + call->state != MBEDTEE_RPC_CALL_ABORTED &&
> + xa_load(&mbedtee->rpc_calls, rpc_index) == call) {
> + __xa_erase(&mbedtee->rpc_calls, rpc_index);
> + drop_remote = true;
> + }
> + xa_unlock_irqrestore(&mbedtee->rpc_calls, flags);
> +
> + if (drop_remote)
> + mbedtee_rpc_call_put(call);
> +
> + /* Drop the caller reference. */
> + mbedtee_rpc_call_put(call);
> +}
> +
> +/*
> + * Abort all outstanding calls at teardown: erase each entry and wake its
> + * waiter so that no workqueue item can remain blocked in a completion
> + * wait when destroy_workqueue() runs.
> + */
> +void mbedtee_rpc_calls_abort(struct mbedtee_device *mbedtee)
> +{
> + struct mbedtee_rpc_call *call;
> + unsigned long flags;
> + unsigned long idx;
> +
> + mutex_lock(&mbedtee->rpc_calls_mutex);
> + WRITE_ONCE(mbedtee->stopping, true);
> + /*
> + * Hold xa_lock across the whole walk so a concurrent
> + * mbedtee_rpc_complete_call() cannot erase entries mid-iteration.
> + * xa_for_each() only takes RCU internally, so it does not recurse
> + * on xa_lock.
> + */
> + xa_lock_irqsave(&mbedtee->rpc_calls, flags);
> + xa_for_each(&mbedtee->rpc_calls, idx, call) {
> + if (xchg(&call->state, MBEDTEE_RPC_CALL_ABORTED) ==
> + MBEDTEE_RPC_CALL_ACTIVE)
> + complete(&call->c);
> + }
> + xa_unlock_irqrestore(&mbedtee->rpc_calls, flags);
> + mutex_unlock(&mbedtee->rpc_calls_mutex);
> +}
> +
> +/*
> + * Release the XArray at teardown. Any entries left here are calls the TEE
> + * never completed; it may still hold their rpc_phys, so we deliberately
> + * leak (quarantine) them rather than risk a cross-world use-after-free.
> + */
> +void mbedtee_rpc_calls_release(struct mbedtee_device *mbedtee)
> +{
> + struct mbedtee_rpc_call *call;
> + unsigned long idx;
> + unsigned int quarantined = 0;
> +
> + xa_for_each(&mbedtee->rpc_calls, idx, call) {
> + xa_erase(&mbedtee->rpc_calls, idx);
> + /* No quiesce ACK exists, so retain the remote reference. */
> + quarantined++;
> + }
> + xa_destroy(&mbedtee->rpc_calls);
> + mutex_destroy(&mbedtee->rpc_calls_mutex);
> +
> + if (quarantined)
> + dev_warn(mbedtee->dev, "quarantined %u RPC calls at release\n",
> + quarantined);
> +}
> +
> +void mbedtee_rpc_complete_call(struct mbedtee_device *mbedtee,
> + u64 waiter_id)
> +{
> + struct mbedtee_rpc_call *call;
> + unsigned long rpc_index;
> + unsigned long flags;
> + unsigned int state;
> +
> + rpc_index = (unsigned long)waiter_id;
> + if ((u64)rpc_index != waiter_id)
> + return;
> +
> + xa_lock_irqsave(&mbedtee->rpc_calls, flags);
> + call = xa_load(&mbedtee->rpc_calls, rpc_index);
> + if (!call) {
> + xa_unlock_irqrestore(&mbedtee->rpc_calls, flags);
> + return;
> + }
> +
> + state = cmpxchg(&call->state, MBEDTEE_RPC_CALL_ACTIVE,
> + MBEDTEE_RPC_CALL_DONE);
> + __xa_erase(&mbedtee->rpc_calls, rpc_index);
> + xa_unlock_irqrestore(&mbedtee->rpc_calls, flags);
> +
> + /*
> + * Wake the waiter before dropping the XArray reference: a killed
> + * waiter that found the entry erased may release its own reference
> + * concurrently, so the put must be the last touch of the call.
> + */
> + if (state == MBEDTEE_RPC_CALL_ACTIVE)
> + complete(&call->c);
> + mbedtee_rpc_call_put(call);
> +}
> +
> +long mbedtee_rpc_wait_for_completion(struct mbedtee_device *mbedtee,
> + struct mbedtee_rpc_call *call, bool killable)
> +{
> + long ret;
> + unsigned int state;
> + unsigned long flags;
> + unsigned long rpc_index;
> +
> + if (!killable) {
> + wait_for_completion(&call->c);
> + return READ_ONCE(call->state) == MBEDTEE_RPC_CALL_ABORTED ?
> + -ESHUTDOWN : 0;
> + }
> +
> + rpc_index = (unsigned long)call->rpc.waiter_id;
> +
> + ret = wait_for_completion_killable(&call->c);
> + if (ret == 0)
> + return READ_ONCE(call->state) == MBEDTEE_RPC_CALL_ABORTED ?
> + -ESHUTDOWN : 0;
> +
> + /*
> + * Synchronize with mbedtee_rpc_complete_call() via the
> + * xa_lock. If complete_call already consumed this entry
> + * before we acquired the lock, the entry is already gone
> + * from the xarray and the TEE already completed (or freed)
> + * the call -- treat as success since the RPC is finished.
> + * If the entry is still present, we hold the lock so
> + * complete_call cannot race with our state transition.
> + */
> + xa_lock_irqsave(&mbedtee->rpc_calls, flags);
> + if (xa_load(&mbedtee->rpc_calls, rpc_index) != call) {
> + state = READ_ONCE(call->state);
> + xa_unlock_irqrestore(&mbedtee->rpc_calls, flags);
> + return state == MBEDTEE_RPC_CALL_ABORTED ? -ESHUTDOWN : 0;
> + }
> +
> + state = cmpxchg(&call->state, MBEDTEE_RPC_CALL_ACTIVE,
> + MBEDTEE_RPC_CALL_INTERRUPTED);
> + if (state == MBEDTEE_RPC_CALL_DONE) {
> + xa_unlock_irqrestore(&mbedtee->rpc_calls, flags);
> + return 0;
> + }
> +
> + if (state == MBEDTEE_RPC_CALL_ACTIVE) {
> + /* Publish interruption state before the TEE waiter reads it. */
> + smp_store_release(&call->rpc.interrupted, true);
> + xa_unlock_irqrestore(&mbedtee->rpc_calls, flags);
> + return ret;
> + }
> +
> + xa_unlock_irqrestore(&mbedtee->rpc_calls, flags);
> + return state == MBEDTEE_RPC_CALL_ABORTED ? -ESHUTDOWN : ret;
> +}
> +
> +/*
> + * Non-interruptible wait bounded by @timeout: on expiry the call is marked
> + * INTERRUPTED (remote ref retained) and -ETIMEDOUT is returned, so a hung
> + * TEE cannot block the caller forever.
> + */
> +long mbedtee_rpc_wait_for_completion_timeout(struct mbedtee_device *mbedtee,
> + struct mbedtee_rpc_call *call,
> + unsigned long timeout)
> +{
> + unsigned long flags;
> + unsigned long rpc_index;
> + unsigned int state;
> +
> + if (wait_for_completion_timeout(&call->c, timeout))
> + return READ_ONCE(call->state) == MBEDTEE_RPC_CALL_ABORTED ?
> + -ESHUTDOWN : 0;
> +
> + rpc_index = (unsigned long)call->rpc.waiter_id;
> + xa_lock_irqsave(&mbedtee->rpc_calls, flags);
> + if (xa_load(&mbedtee->rpc_calls, rpc_index) != call) {
> + state = READ_ONCE(call->state);
> + xa_unlock_irqrestore(&mbedtee->rpc_calls, flags);
> + return state == MBEDTEE_RPC_CALL_ABORTED ? -ESHUTDOWN : 0;
> + }
> +
> + state = cmpxchg(&call->state, MBEDTEE_RPC_CALL_ACTIVE,
> + MBEDTEE_RPC_CALL_INTERRUPTED);
> + if (state == MBEDTEE_RPC_CALL_ACTIVE)
> + /* Publish interruption before the TEE observes the request. */
> + smp_store_release(&call->rpc.interrupted, true);
> + xa_unlock_irqrestore(&mbedtee->rpc_calls, flags);
> +
> + if (state == MBEDTEE_RPC_CALL_ACTIVE)
> + return -ETIMEDOUT;
> +
> + return state == MBEDTEE_RPC_CALL_ABORTED ? -ESHUTDOWN : 0;
> +}
> +
> +/* Local helpers for encoding/decoding the 4-bit-per-parameter type field. */
> +static inline u32 mbedtee_param_type_get(u32 types, unsigned int idx)
> +{
> + return (types >> (idx * 4)) & 0xF;
> +}
> +
> +static inline u32 mbedtee_param_type_set(u32 type, unsigned int idx)
> +{
> + return (type & 0xF) << (idx * 4);
> +}
> +
> +static int mbedtee_param_decode(struct tee_param *params,
> + size_t num_params, const struct rpc_param *rp)
> +{
> + size_t n;
> +
> + if (num_params > ARRAY_SIZE(rp->params))
> + return -EINVAL;
> +
> + for (n = 0; n < num_params; n++) {
> + struct tee_param *p = params + n;
> + const union rpc_tee_param *rtp = rp->params + n;
> + u32 attr = mbedtee_param_type_get(rp->params_type, n);
> +
> + /*
> + * The TEE must not change the parameter type: the generic
> + * TEE layer releases memrefs based on the attributes the
> + * client supplied, so a type change here would leak the
> + * shared memory reference.
> + */
> + if (attr != p->attr)
> + return -EINVAL;
> +
> + switch (attr) {
> + case TEE_IOCTL_PARAM_ATTR_TYPE_NONE:
> + memset(&p->u, 0, sizeof(p->u));
> + break;
> + case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT:
> + case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
> + case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
> + p->u.value.a = rtp->value.a;
> + p->u.value.b = rtp->value.b;
> + break;
> + case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
> + case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
> + case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
> + p->u.memref.size = rtp->memref.size;
> + break;
> + default:
> + return -EINVAL;
> + }
> + }
> + return 0;
> +}
> +
> +static int mbedtee_param_encode(struct rpc_param *rp,
> + size_t num_params, const struct tee_param *params)
> +{
> + size_t n;
> +
> + if (num_params > ARRAY_SIZE(rp->params))
> + return -EINVAL;
> +
> + rp->params_type = TEE_IOCTL_PARAM_ATTR_TYPE_NONE;
> +
> + for (n = 0; n < num_params; n++) {
> + const struct tee_param *p = params + n;
> + union rpc_tee_param *rtp = rp->params + n;
> +
> + rp->params_type |= mbedtee_param_type_set(p->attr, n);
> +
> + switch (p->attr) {
> + case TEE_IOCTL_PARAM_ATTR_TYPE_NONE:
> + memset(rtp, 0, sizeof(*rtp));
> + break;
> + case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT:
> + case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
> + case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
> + rtp->value.a = p->u.value.a;
> + rtp->value.b = p->u.value.b;
> + break;
> + case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
> + case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
> + case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
> + if (p->u.memref.shm)
> + rtp->memref.id = p->u.memref.shm->sec_world_id;
> + else
> + rtp->memref.id = 0; /* invalid-id @ mbedtee */
> + rtp->memref.size = p->u.memref.size;
> + rtp->memref.offset = p->u.memref.shm_offs;
> + break;
> + default:
> + return -EINVAL;
> + }
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * cancel_req() and shm_{register,unregister} still return Linux errno to the
> + * kernel TEE core. Preserve any local transport failure in @ret; otherwise
> + * fold a non-success TEE-side GP status into the generic -EIO expected by
> + * these internal-only hooks.
> + */
> +static int mbedtee_rpc_gp_ret_to_errno(int ret, s32 gp_ret)
> +{
> + if (ret)
> + return ret;
> +
> + return gp_ret == TEEC_SUCCESS ? 0 : -EIO;
> +}
> +
> +struct mbedtee_session *
> +mbedtee_find_session_locked(struct mbedtee_context_data *ctxdata,
> + u32 session_id)
> +{
> + struct mbedtee_session *sess;
> +
> + list_for_each_entry(sess, &ctxdata->sess_list, list_node)
> + if (sess->session_id == session_id)
> + return sess;
> +
> + return NULL;
> +}
> +
> +int mbedtee_open_session(struct tee_context *ctx,
> + struct tee_ioctl_open_session_arg *arg,
> + struct tee_param *param)
> +{
> + int ret;
> + u32 session_id = 0;
> + struct mbedtee_context_data *ctxdata = ctx->data;
> + struct mbedtee_device *mbedtee = tee_get_drvdata(ctx->teedev);
> + struct mbedtee_rpc_call *call;
> + struct rpc_param *rp;
> + struct mbedtee_session *sess;
> +
> + sess = kzalloc_obj(*sess, GFP_KERNEL);
> + if (!sess)
> + return -ENOMEM;
> +
> + ret = mbedtee_rpc_call_alloc(mbedtee, sizeof(*rp), &call);
> + if (ret != 0) {
> + kfree(sess);
> + return ret;
> + }
> +
> + rp = (struct rpc_param *)call->rpc.data;
> +
> + ret = mbedtee_param_encode(rp, arg->num_params, param);
> + if (ret) {
> + kfree(sess);
> + mbedtee_rpc_call_free(mbedtee, call);
> + return ret;
> + }
> +
> + memcpy(rp->uuid, arg->uuid, sizeof(arg->uuid));
> + memcpy(rp->clnt_uuid, arg->clnt_uuid, sizeof(arg->clnt_uuid));
> + rp->ret_origin = TEEC_ORIGIN_COMMS;
> +
> + ret = mbedtee_rpc_yieldcall(mbedtee, MBEDTEE_RPC_OPEN_SESSION, call, false);
> +
> + dev_dbg(mbedtee->dev, "open session ret %d gp_ret %d\n", ret,
> + call->rpc.ret);
> +
> + if (ret == 0 && call->rpc.ret == TEEC_SUCCESS) {
> + session_id = rp->session_id;
> + sess->session_id = session_id;
> + mutex_lock(&ctxdata->mutex);
> + list_add(&sess->list_node, &ctxdata->sess_list);
> + mutex_unlock(&ctxdata->mutex);
> + } else {
> + kfree(sess);
> + }
> +
> + if (ret != 0) {
> + arg->ret = TEEC_ERROR_COMMUNICATION;
> + arg->ret_origin = TEEC_ORIGIN_COMMS;
> + } else if (mbedtee_param_decode(param, arg->num_params, rp)) {
> + arg->ret = TEEC_ERROR_COMMUNICATION;
> + arg->ret_origin = TEEC_ORIGIN_COMMS;
> + if (call->rpc.ret == TEEC_SUCCESS)
> + mbedtee_close_session(ctx, session_id);
> + } else {
> + arg->session = rp->session_id;
> + arg->ret = (u32)call->rpc.ret;
> + arg->ret_origin = rp->ret_origin;
> + }
> +
> + mbedtee_rpc_call_free(mbedtee, call);
> + return 0;
> +}
> +
> +int mbedtee_invoke_func(struct tee_context *ctx,
> + struct tee_ioctl_invoke_arg *arg,
> + struct tee_param *param)
> +{
> + int ret;
> + struct mbedtee_context_data *ctxdata = ctx->data;
> + struct mbedtee_device *mbedtee = tee_get_drvdata(ctx->teedev);
> + struct mbedtee_rpc_call *call;
> + struct rpc_param *rp;
> + struct mbedtee_session *sess;
> +
> + mutex_lock(&ctxdata->mutex);
> + sess = mbedtee_find_session_locked(ctxdata, arg->session);
> + if (!sess || sess->closing) {
> + mutex_unlock(&ctxdata->mutex);
> + return -EINVAL;
> + }
> + mutex_unlock(&ctxdata->mutex);
> +
> + ret = mbedtee_rpc_call_alloc(mbedtee, sizeof(*rp), &call);
> + if (ret != 0)
> + return ret;
> +
> + rp = (struct rpc_param *)call->rpc.data;
> +
> + rp->session_id = arg->session;
> + rp->cmd_id = arg->func;
> + rp->ret_origin = TEEC_ORIGIN_COMMS;
> +
> + ret = mbedtee_param_encode(rp, arg->num_params, param);
> + if (ret) {
> + mbedtee_rpc_call_free(mbedtee, call);
> + return ret;
> + }
> +
> + ret = mbedtee_rpc_yieldcall(mbedtee, MBEDTEE_RPC_INVOKE_SESSION, call, true);
> +
> + if (ret != 0) {
> + /*
> + * On -ERESTARTSYS/-ETIMEDOUT/-ESHUTDOWN the call is INTERRUPTED
> + * or ABORTED, so free() drops only the caller reference; the
> + * XArray keeps the remote reference until the TEE completes it.
> + */
> + arg->ret = TEEC_ERROR_COMMUNICATION;
> + arg->ret_origin = TEEC_ORIGIN_COMMS;
> + mbedtee_rpc_call_free(mbedtee, call);
> + return 0;
> + }
> +
> + dev_dbg(mbedtee->dev, "invoke session ret %d gp_ret %d\n", ret,
> + call->rpc.ret);
> +
> + if (mbedtee_param_decode(param, arg->num_params, rp)) {
> + arg->ret = TEEC_ERROR_COMMUNICATION;
> + arg->ret_origin = TEEC_ORIGIN_COMMS;
> + } else {
> + arg->ret = (u32)call->rpc.ret;
> + arg->ret_origin = rp->ret_origin;
> + }
> +
> + mbedtee_rpc_call_free(mbedtee, call);
> + return 0;
> +}
> +
> +int mbedtee_close_session(struct tee_context *ctx, u32 session)
> +{
> + int ret;
> + struct mbedtee_context_data *ctxdata = ctx->data;
> + struct mbedtee_device *mbedtee = tee_get_drvdata(ctx->teedev);
> + struct mbedtee_rpc_call *call;
> + struct rpc_param *rp;
> + struct mbedtee_session *sess;
> + bool remove;
> +
> + mutex_lock(&ctxdata->mutex);
> + sess = mbedtee_find_session_locked(ctxdata, session);
> + if (!sess) {
> + mutex_unlock(&ctxdata->mutex);
> + return -EINVAL;
> + }
> + if (sess->closing) {
> + mutex_unlock(&ctxdata->mutex);
> + return -EBUSY;
> + }
> + sess->closing = true;
> + mutex_unlock(&ctxdata->mutex);
> +
> + ret = mbedtee_rpc_call_alloc(mbedtee, sizeof(*rp), &call);
> + if (ret != 0)
> + goto out_session;
> +
> + rp = (struct rpc_param *)call->rpc.data;
> + rp->session_id = session;
> +
> + ret = mbedtee_rpc_yieldcall(mbedtee, MBEDTEE_RPC_CLOSE_SESSION, call, false);
> +
> + mbedtee_rpc_call_free(mbedtee, call);
> +
> +out_session:
> + remove = ret == 0 || READ_ONCE(mbedtee->stopping);
> + mutex_lock(&ctxdata->mutex);
> + sess = mbedtee_find_session_locked(ctxdata, session);
> + if (sess) {
> + if (remove)
> + list_del(&sess->list_node);
> + else
> + sess->closing = false;
> + }
> + mutex_unlock(&ctxdata->mutex);
> + if (remove)
> + kfree(sess);
> +
> + return ret;
> +}
> +
> +int mbedtee_cancel_req(struct tee_context *ctx,
> + u32 cancel_id, u32 session)
> +{
> + int ret;
> + struct mbedtee_context_data *ctxdata = ctx->data;
> + struct mbedtee_device *mbedtee = tee_get_drvdata(ctx->teedev);
> + struct mbedtee_rpc_call *call;
> + struct rpc_cancel_req *cancel;
> + struct mbedtee_session *sess;
> +
> + mutex_lock(&ctxdata->mutex);
> + sess = mbedtee_find_session_locked(ctxdata, session);
> + if (!sess || sess->closing) {
> + mutex_unlock(&ctxdata->mutex);
> + return -EINVAL;
> + }
> + mutex_unlock(&ctxdata->mutex);
> +
> + ret = mbedtee_rpc_call_alloc(mbedtee, sizeof(*cancel), &call);
> + if (ret != 0)
> + return ret;
> +
> + cancel = (struct rpc_cancel_req *)call->rpc.data;
> + cancel->session_id = session;
> + cancel->cancel_id = cancel_id;
> +
> + ret = mbedtee_rpc_yieldcall(mbedtee, MBEDTEE_RPC_CANCEL, call, false);
> + ret = mbedtee_rpc_gp_ret_to_errno(ret, call->rpc.ret);
> +
> + mbedtee_rpc_call_free(mbedtee, call);
> +
> + return ret;
> +}
> +
> +int mbedtee_shm_register(struct tee_context *ctx, struct tee_shm *shm,
> + struct page **pages, size_t nr_pages, unsigned long start)
> +{
> + int ret;
> + size_t i, j;
> + u64 *pagearray;
> + struct mbedtee_device *mbedtee = tee_get_drvdata(ctx->teedev);
> + struct mbedtee_rpc_call *call;
> + struct rpc_memref *memref;
> + /* Multiple: number of MBEDTEE_PAGE_SIZE pages per Linux page. */
> + const size_t multiple = PAGE_SIZE / MBEDTEE_PAGE_SIZE;
> +
> + BUILD_BUG_ON(PAGE_SIZE < MBEDTEE_PAGE_SIZE);
> +
> + ret = mbedtee_rpc_call_alloc(mbedtee, sizeof(*memref), &call);
> + if (ret != 0)
> + return ret;
> +
> + memref = (struct rpc_memref *)call->rpc.data;
> +
> + pagearray = kcalloc(nr_pages * multiple, sizeof(*pagearray), GFP_KERNEL);
> + if (!pagearray) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + for (i = 0; i < nr_pages; i++) {
> + for (j = 0; j < multiple; j++)
> + pagearray[i * multiple + j] = MBEDTEE_PAGE_SIZE * j +
> + page_to_phys(pages[i]);
> + }
> +
> + memref->size = tee_shm_get_size(shm);
> + memref->offset = tee_shm_get_page_offset(shm);
> + memref->pages = mbedtee_virt_to_phys(pagearray);
> + memref->cnt = nr_pages * multiple;
> + ret = mbedtee_rpc_yieldcall(mbedtee, MBEDTEE_RPC_REGISTER_SHM, call, false);
> + ret = mbedtee_rpc_gp_ret_to_errno(ret, call->rpc.ret);
> +
> + if (ret == 0)
> + shm->sec_world_id = memref->id;
> +
> + kfree(pagearray);
> +
> +out:
> + mbedtee_rpc_call_free(mbedtee, call);
> + return ret;
> +}
> +
> +int mbedtee_shm_unregister(struct tee_context *ctx,
> + struct tee_shm *shm)
> +{
> + int ret;
> + struct mbedtee_device *mbedtee = tee_get_drvdata(ctx->teedev);
> + struct mbedtee_rpc_call *call;
> + struct rpc_memref *memref;
> +
> + ret = mbedtee_rpc_call_alloc(mbedtee, sizeof(*memref), &call);
> + if (ret != 0)
> + return ret;
> +
> + memref = (struct rpc_memref *)call->rpc.data;
> + memref->id = shm->sec_world_id;
> +
> + ret = mbedtee_rpc_yieldcall(mbedtee, MBEDTEE_RPC_UNREGISTER_SHM, call, false);
> + ret = mbedtee_rpc_gp_ret_to_errno(ret, call->rpc.ret);
> +
> + mbedtee_rpc_call_free(mbedtee, call);
> +
> + return ret;
> +}
> diff --git a/drivers/tee/mbedtee/rpc_caller_arm.c b/drivers/tee/mbedtee/rpc_caller_arm.c
> new file mode 100644
> index 0000000..520b57d
> --- /dev/null
> +++ b/drivers/tee/mbedtee/rpc_caller_arm.c
> @@ -0,0 +1,70 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2020 Xing Loong <xing.xl.loong at gmail.com>
> + * ARM RPC calls to TEE - relies on SMC
> + *
> + * Uses arm_smccc_smc() with SMCCC-compatible calling convention:
> + * Fast call : r0/x0 = fn (bit 31 set), r1-r3/x1-x3 = args.
> + * Yield call : r0/x0 = fn (bit 31 clear), r1/x1 = phys(rpc_cmd).
> + *
> + * ARM fast calls are synchronous SMC instructions.
> + */
> +#include <linux/mm.h>
> +#include <linux/errno.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/arm-smccc.h>
> +#include "mbedtee_drv.h"
> +
> +long mbedtee_rpc_yieldcall(struct mbedtee_device *mbedtee,
> + unsigned long fn, struct mbedtee_rpc_call *call,
> + bool interruptible)
> +{
> + long ret;
> + struct arm_smccc_res res;
> +
> + if (MBEDTEE_RPC_IS_FASTCALL(fn))
> + return -EINVAL;
> +
> + call->rpc.id = fn;
> +
> + arm_smccc_smc(fn, call->rpc_phys,
> + 0, 0, 0, 0, 0, 0, &res);
> + ret = res.a0;
> + if (ret != 0)
> + return ret;
> +
> + return mbedtee_rpc_wait_for_completion(mbedtee, call, interruptible);
> +}
> +
> +long mbedtee_rpc_fastcall(struct mbedtee_device *mbedtee,
> + unsigned long fn, unsigned long a0,
> + unsigned long a1, unsigned long a2)
> +{
> + struct arm_smccc_res res;
> +
> + if (!MBEDTEE_RPC_IS_FASTCALL(fn))
> + return -EINVAL;
> +
> + arm_smccc_smc(fn, a0, a1, a2, 0, 0, 0, 0, &res);
> +
> + return (long)res.a0;
> +}
> +
> +/*
> + * ARM uses direct SMC; no caller-side ring buffer initialisation needed.
> + */
> +int mbedtee_r2t_init(struct mbedtee_device *mbedtee)
> +{
> + return 0;
> +}
> +
> +void mbedtee_r2t_stop(struct mbedtee_device *mbedtee)
> +{
> +}
> +
> +void mbedtee_r2t_uninit(struct mbedtee_device *mbedtee)
> +{
> +}
> diff --git a/drivers/tee/mbedtee/rpc_caller_riscv.c b/drivers/tee/mbedtee/rpc_caller_riscv.c
> new file mode 100644
> index 0000000..98f8cd3
> --- /dev/null
> +++ b/drivers/tee/mbedtee/rpc_caller_riscv.c
> @@ -0,0 +1,238 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2025 Xing Loong <xing.xl.loong at gmail.com>
> + * REE->TEE RPC calls for RISC-V (IMSIC)
> + */
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/mm.h>
> +#include <linux/errno.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/jiffies.h>
> +#include <linux/of_address.h>
> +#include <linux/io.h>
> +#include <linux/sizes.h>
> +
> +#include "mbedtee_drv.h"
> +
> +/*
> + * Time the writer may wait for ring space before giving up. Transient
> + * fullness is common under high concurrency; permanent fullness means
> + * the TEE is no longer draining and must not hang ioctls forever.
> + */
> +#define MBEDTEE_R2T_FULL_TIMEOUT (10 * HZ)
> +#define MBEDTEE_R2T_CALL_TIMEOUT (30 * HZ)
> +
> +static bool rpc_ring_enough(struct mbedtee_r2t_ctx *ctx, size_t size)
> +{
> + u32 wr;
> + u32 rd;
> + u32 remain;
> +
> + wr = READ_ONCE(ctx->ring_wr);
> + /* Pair with callee release store when publishing ring->rd */
> + rd = smp_load_acquire(&ctx->ring->rd);
> +
> + if (rd > ctx->ring_sz || wr > ctx->ring_sz)
> + return false;
> +
> + if (rd <= wr)
> + remain = ctx->ring_sz + rd - wr;
> + else
> + remain = rd - wr;
> +
> + return remain > size;
> +}
> +
> +static void rpc_ring_write(struct mbedtee_r2t_ctx *ctx,
> + void *data, size_t size)
> +{
> + struct rpc_ringbuf *shm = ctx->ring;
> + u32 remain;
> + u32 wr = READ_ONCE(ctx->ring_wr);
> +
> + if (wr + size > ctx->ring_sz) {
> + remain = wr + size - ctx->ring_sz;
> + memcpy(&shm->mem[wr], data, size - remain);
> + memcpy(&shm->mem[0], (char *)data + size - remain, remain);
> + wr = remain;
> + } else {
> + memcpy(&shm->mem[wr], data, size);
> + wr += size;
> + }
> +
> + WRITE_ONCE(ctx->ring_wr, wr);
> + /* Publish writer index after payload bytes become visible. */
> + smp_store_release(&shm->wr, wr);
> +}
> +
> +/*
> + * Wait for @size bytes of space in the R2T ring, then write @data
> + * atomically under the ring lock. Returns 0 on success.
> + */
> +static int r2t_ring_write_wait(struct mbedtee_r2t_ctx *ctx,
> + void *data, size_t size)
> +{
> + unsigned long deadline = jiffies + MBEDTEE_R2T_FULL_TIMEOUT;
> + unsigned long flags;
> +
> + for (;;) {
> + spin_lock_irqsave(&ctx->lock, flags);
> + if (READ_ONCE(ctx->stopping)) {
> + spin_unlock_irqrestore(&ctx->lock, flags);
> + return -ESHUTDOWN;
> + }
> + if (rpc_ring_enough(ctx, size)) {
> + rpc_ring_write(ctx, data, size);
> + spin_unlock_irqrestore(&ctx->lock, flags);
> + return 0;
> + }
> + spin_unlock_irqrestore(&ctx->lock, flags);
> +
> + if (time_after_eq(jiffies, deadline))
> + return -ENOSPC;
> + usleep_range(1000, 2000);
> + }
> +}
> +
> +long mbedtee_rpc_yieldcall(struct mbedtee_device *mbedtee,
> + unsigned long fn, struct mbedtee_rpc_call *call,
> + bool interruptible)
> +{
> + struct mbedtee_r2t_ctx *ctx = &mbedtee->r2t;
> + u64 phys;
> + int ret;
> +
> + if (!ctx->ring)
> + return -ENXIO;
> +
> + if (MBEDTEE_RPC_IS_FASTCALL(fn))
> + return -EINVAL;
> +
> + call->rpc.id = fn;
> +
> + phys = call->rpc_phys;
> + ret = r2t_ring_write_wait(ctx, &phys, sizeof(phys));
> + if (ret != 0) {
> + dev_err_ratelimited(mbedtee->dev, "rpc ring full\n");
> + return ret;
> + }
> +
> + if (interruptible)
> + return mbedtee_rpc_wait_for_completion(mbedtee, call, true);
> +
> + return mbedtee_rpc_wait_for_completion_timeout(mbedtee, call,
> + MBEDTEE_R2T_CALL_TIMEOUT);
> +}
> +
> +long mbedtee_rpc_fastcall(struct mbedtee_device *mbedtee,
> + unsigned long fn, unsigned long a0,
> + unsigned long a1, unsigned long a2)
> +{
> + struct mbedtee_r2t_ctx *ctx = &mbedtee->r2t;
> + struct mbedtee_rpc_call *call;
> + u64 phys;
> + int ret;
> +
> + if (!ctx->ring)
> + return -ENXIO;
> +
> + if (!MBEDTEE_RPC_IS_FASTCALL(fn))
> + return -EINVAL;
> +
> + ret = mbedtee_rpc_call_alloc(mbedtee, 3 * sizeof(u64), &call);
> + if (ret != 0)
> + return ret;
> +
> + call->rpc.id = fn;
> + call->rpc.size = 3 * sizeof(u64);
> + call->rpc.data[0] = a0;
> + call->rpc.data[1] = a1;
> + call->rpc.data[2] = a2;
> +
> + phys = call->rpc_phys;
> + ret = r2t_ring_write_wait(ctx, &phys, sizeof(phys));
> + if (ret != 0) {
> + dev_err_ratelimited(mbedtee->dev, "rpc ring full\n");
> + mbedtee_rpc_call_free(mbedtee, call);
> + return ret;
> + }
> +
> + ret = mbedtee_rpc_wait_for_completion_timeout(mbedtee, call,
> + MBEDTEE_R2T_CALL_TIMEOUT);
> + if (ret != 0) {
> + mbedtee_rpc_call_free(mbedtee, call);
> + return ret;
> + }
> +
> + ret = call->rpc.ret;
> + mbedtee_rpc_call_free(mbedtee, call);
> +
> + return ret;
> +}
> +
> +int mbedtee_r2t_init(struct mbedtee_device *mbedtee)
> +{
> + struct mbedtee_r2t_ctx *ctx = &mbedtee->r2t;
> + struct device_node *node = mbedtee->dev->of_node;
> + struct resource res;
> + int ret;
> +
> + memset(ctx, 0, sizeof(*ctx));
> + spin_lock_init(&ctx->lock);
> +
> + ret = mbedtee_get_resource(node, "r2t-ring", &res);
> + if (ret)
> + return ret;
> +
> + if (resource_size(&res) <= sizeof(struct rpc_ringbuf)) {
> + dev_err(mbedtee->dev, "r2t-ring too small\n");
> + return -EINVAL;
> + }
> +
> + ctx->ring = memremap(res.start, resource_size(&res),
> + MEMREMAP_WB);
> + if (!ctx->ring) {
> + dev_err(mbedtee->dev, "failed to map r2t ring at %pa\n",
> + &res.start);
> + return -ENOMEM;
> + }
> + ctx->ring_sz = resource_size(&res) - sizeof(struct rpc_ringbuf);
> + /* Read initial writer index with acquire for coherent ring bootstrap. */
> + WRITE_ONCE(ctx->ring_wr, smp_load_acquire(&ctx->ring->wr));
> +
> + dev_dbg(mbedtee->dev, "r2t-ring %pa\n", &res.start);
> +
> + return 0;
> +}
> +
> +void mbedtee_r2t_stop(struct mbedtee_device *mbedtee)
> +{
> + struct mbedtee_r2t_ctx *ctx = &mbedtee->r2t;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ctx->lock, flags);
> + WRITE_ONCE(ctx->stopping, true);
> + spin_unlock_irqrestore(&ctx->lock, flags);
> +}
> +
> +void mbedtee_r2t_uninit(struct mbedtee_device *mbedtee)
> +{
> + struct mbedtee_r2t_ctx *ctx;
> +
> + if (!mbedtee)
> + return;
> +
> + ctx = &mbedtee->r2t;
> + if (ctx->ring) {
> + /* r2t_init() failure lands here with no prior stop; flag first. */
> + mbedtee_r2t_stop(mbedtee);
> + memunmap(ctx->ring);
> + ctx->ring = NULL;
> + ctx->ring_sz = 0;
> + ctx->ring_wr = 0;
> + }
> +}
> diff --git a/drivers/tee/mbedtee/shm_pool.c b/drivers/tee/mbedtee/shm_pool.c
> new file mode 100644
> index 0000000..708ab24
> --- /dev/null
> +++ b/drivers/tee/mbedtee/shm_pool.c
> @@ -0,0 +1,105 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2015, Linaro Limited
> + * Copyright (c) 2017, EPAM Systems
> + * Copyright (c) 2020 Xing Loong <xing.xl.loong at gmail.com>
> + */
> +#include <linux/device.h>
> +#include <linux/genalloc.h>
> +#include <linux/slab.h>
> +
> +#include "mbedtee_drv.h"
> +
> +static int pool_op_alloc(struct tee_shm_pool *pool,
> + struct tee_shm *shm, size_t size, size_t align)
> +{
> + unsigned int order = get_order(size);
> + struct page *page;
> + int rc = 0;
> +
> + 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;
> +
> + if (!(shm->flags & TEE_SHM_PRIV)) {
> + struct mbedtee_device *mbedtee = tee_get_drvdata(shm->ctx->teedev);
> +
> + if (mbedtee->yield) {
> + unsigned int nr_pages = 1 << order;
> + unsigned int i;
> + struct page **pages;
> +
> + pages = kmalloc_array(nr_pages, sizeof(*pages), GFP_KERNEL);
> + if (!pages) {
> + rc = -ENOMEM;
> + goto err_pages;
> + }
> +
> + for (i = 0; i < nr_pages; i++)
> + pages[i] = page + i;
> +
> + rc = mbedtee_shm_register(shm->ctx, shm, pages,
> + nr_pages,
> + (unsigned long)shm->kaddr);
> + kfree(pages);
> + if (rc)
> + goto err_pages;
> + }
> + }
> +
> + return 0;
> +
> +err_pages:
> + free_pages((unsigned long)shm->kaddr, get_order(shm->size));
> + shm->kaddr = NULL;
> + return rc;
> +}
> +
> +static void pool_op_free(struct tee_shm_pool *pool,
> + struct tee_shm *shm)
> +{
> + if (!(shm->flags & TEE_SHM_PRIV)) {
> + struct mbedtee_device *mbedtee = tee_get_drvdata(shm->ctx->teedev);
> +
> + if (mbedtee->yield && shm->sec_world_id)
> + mbedtee_shm_unregister(shm->ctx, shm);
> + }
> +
> + 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,
> +};
> +
> +/**
> + * mbedtee_shm_pool_alloc_pages() - create page-based allocator pool
> + *
> + * This pool is used when MbedTEE supports dynamic shared memory. Command
> + * buffers and similar structures are allocated from kernel's own memory.
> + *
> + * Return: pointer to a tee_shm_pool or ERR_PTR on failure
> + */
> +struct tee_shm_pool *mbedtee_shm_pool_alloc_pages(void)
> +{
> + struct tee_shm_pool *pool = kzalloc_obj(*pool, GFP_KERNEL);
> +
> + if (!pool)
> + return ERR_PTR(-ENOMEM);
> +
> + pool->ops = &pool_ops;
> +
> + return pool;
> +}
> diff --git a/drivers/tee/mbedtee/shm_pool.h b/drivers/tee/mbedtee/shm_pool.h
> new file mode 100644
> index 0000000..4510676
> --- /dev/null
> +++ b/drivers/tee/mbedtee/shm_pool.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2015, Linaro Limited
> + * Copyright (c) 2016, EPAM Systems
> + * Copyright (c) 2020 Xing Loong <xing.xl.loong at gmail.com>
> + */
> +
> +#ifndef SHM_POOL_H
> +#define SHM_POOL_H
> +
> +#include <linux/tee_drv.h>
> +
> +struct tee_shm_pool *mbedtee_shm_pool_alloc_pages(void);
> +
> +#endif
> diff --git a/drivers/tee/mbedtee/supp.c b/drivers/tee/mbedtee/supp.c
> new file mode 100644
> index 0000000..1408403
> --- /dev/null
> +++ b/drivers/tee/mbedtee/supp.c
> @@ -0,0 +1,311 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2015, Linaro Limited
> + * Copyright (c) 2020 Xing Loong <xing.xl.loong at gmail.com>
> + */
> +#include <linux/device.h>
> +#include <linux/sched.h>
> +#include <linux/slab.h>
> +#include <linux/uaccess.h>
> +
> +#include "mbedtee_drv.h"
> +
> +struct mbedtee_supp_req {
> + u32 func;
> +
> + struct list_head node;
> + struct task_struct *worker;
> + struct tee_context *ctx; /* owning supplicant context */
> +
> + struct tee_shm *shm;
> + void *data;
> + size_t size;
> +
> + struct completion c;
> +};
> +
> +static int mbedtee_supp_check_recv_params(size_t num_params,
> + struct tee_param *params)
> +{
> + if (num_params != 1)
> + return -EINVAL;
> +
> + if (!tee_param_is_memref(params) || !params->u.memref.shm)
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +void mbedtee_supp_init(struct mbedtee_supp *supp)
> +{
> + memset(supp, 0, sizeof(*supp));
> + mutex_init(&supp->mutex);
> + init_completion(&supp->reqs_c);
> + INIT_LIST_HEAD(&supp->reqs);
> + INIT_LIST_HEAD(&supp->active_reqs);
> +}
> +
> +void mbedtee_supp_uninit(struct mbedtee_supp *supp)
> +{
> + mutex_destroy(&supp->mutex);
> +}
> +
> +static void mbedtee_supp_complete_req(struct mbedtee_supp_req *r)
> +{
> + list_del_init(&r->node);
> + if (r->shm)
> + tee_shm_put(r->shm);
> + r->shm = NULL;
> + /* Tell the TEE that the request failed, not stale success data. */
> + if (r->data && r->size >= sizeof(struct supp_cmd_hdr))
> + ((struct supp_cmd_hdr *)r->data)->ret = TEEC_ERROR_COMMUNICATION;
> + complete(&r->c);
> +}
> +
> +void mbedtee_supp_release(struct mbedtee_supp *supp, struct tee_context *ctx)
> +{
> + struct mbedtee_supp_req *r, *n;
> +
> + mutex_lock(&supp->mutex);
> +
> + /*
> + * Cancel only requests owned by @ctx. Unclaimed requests and
> + * requests owned by other supplicant contexts are left alone.
> + */
> + list_for_each_entry_safe(r, n, &supp->reqs, node) {
> + if (r->ctx != ctx)
> + continue;
> + mbedtee_supp_complete_req(r);
> + }
> +
> + list_for_each_entry_safe(r, n, &supp->active_reqs, node) {
> + if (r->ctx != ctx)
> + continue;
> + mbedtee_supp_complete_req(r);
> + }
> +
> + if (supp->ctx == ctx)
> + supp->ctx = NULL;
> +
> + mutex_unlock(&supp->mutex);
> +}
> +
> +void mbedtee_supp_abort_all(struct mbedtee_supp *supp)
> +{
> + struct mbedtee_supp_req *r, *n;
> +
> + mutex_lock(&supp->mutex);
> + supp->shutting_down = true;
> +
> + list_for_each_entry_safe(r, n, &supp->reqs, node)
> + mbedtee_supp_complete_req(r);
> +
> + list_for_each_entry_safe(r, n, &supp->active_reqs, node)
> + mbedtee_supp_complete_req(r);
> +
> + supp->ctx = NULL;
> +
> + mutex_unlock(&supp->mutex);
> + complete_all(&supp->reqs_c);
> +}
> +
> +static int supp_enqueue_req(struct mbedtee_supp *supp,
> + struct mbedtee_supp_req *req)
> +{
> + int ret = 0;
> +
> + mutex_lock(&supp->mutex);
> + if (supp->shutting_down)
> + ret = -ESHUTDOWN;
> + else
> + list_add_tail(&req->node, &supp->reqs);
> + mutex_unlock(&supp->mutex);
> +
> + return ret;
> +}
> +
> +/*
> + * Receive an RPC request from TEE and dispatch it to supplicant.
> + * Blocks until the supplicant sends back the result.
> + */
> +void mbedtee_supp_handler(struct mbedtee_device *mbedtee,
> + u32 func, void *data, size_t size)
> +{
> + struct mbedtee_supp *supp = &mbedtee->supp;
> + struct mbedtee_supp_req *req = kzalloc_obj(*req, GFP_KERNEL);
> + struct supp_cmd_hdr *cmd = data;
> + int ret;
> +
> + if (!req) {
> + if (cmd && size >= sizeof(*cmd))
> + cmd->ret = TEEC_ERROR_OUT_OF_MEMORY;
> + return;
> + }
> +
> + init_completion(&req->c);
> + req->func = func;
> + req->data = data;
> + req->size = size;
> +
> + ret = supp_enqueue_req(supp, req);
> + if (ret != 0) {
> + if (cmd && size >= sizeof(*cmd))
> + cmd->ret = TEEC_ERROR_COMMUNICATION;
> + kfree(req);
> + return;
> + }
> +
> + /* Wake up the supplicant daemon to handle this request. */
> + complete(&supp->reqs_c);
> +
> + /*
> + * Wait for the supplicant to process and return the result, like
> + * OP-TEE does. If the supplicant dies, mbedtee_supp_release()
> + * completes the request, so this cannot block forever.
> + */
> + wait_for_completion(&req->c);
> +
> + kfree(req);
> +}
> +
> +/*
> + * Called by supplicant to receive the next pending request.
> + */
> +int mbedtee_supp_recv(struct tee_context *ctx,
> + u32 *func, u32 *num_params, struct tee_param *param)
> +{
> + struct tee_device *teedev = ctx->teedev;
> + struct mbedtee_device *mbedtee = tee_get_drvdata(teedev);
> + struct mbedtee_supp *supp = &mbedtee->supp;
> + struct mbedtee_supp_req *req;
> + struct mbedtee_context_data *d = ctx->data;
> + struct tee_shm *shm;
> + int ret;
> +
> + ret = mbedtee_supp_check_recv_params(*num_params, param);
> + if (ret != 0)
> + return ret;
> +
> + shm = param->u.memref.shm;
> + shm = tee_shm_get_from_id(ctx, shm->id);
> + tee_shm_put(param->u.memref.shm);
> + if (IS_ERR(shm)) {
> + param->u.memref.shm = NULL;
> + return PTR_ERR(shm);
> + }
> + param->u.memref.shm = shm;
> +
> + d->is_supp_ctx = true;
> +
> + /*
> + * Pop, own and validate the request in one critical section so that
> + * a concurrent supp_abort_all() can never free the request while
> + * it is being prepared here.
> + */
> + while (true) {
> + mutex_lock(&supp->mutex);
> + if (supp->shutting_down) {
> + mutex_unlock(&supp->mutex);
> + ret = -ESHUTDOWN;
> + goto err;
> + }
> +
> + req = list_first_entry_or_null(&supp->reqs,
> + struct mbedtee_supp_req, node);
> + if (!req) {
> + mutex_unlock(&supp->mutex);
> + if (wait_for_completion_interruptible(&supp->reqs_c)) {
> + ret = -ERESTARTSYS;
> + goto err;
> + }
> + continue;
> + }
> +
> + list_del_init(&req->node);
> + req->worker = current;
> + req->ctx = ctx;
> + list_add_tail(&req->node, &supp->active_reqs);
> +
> + if (req->size > param->u.memref.size) {
> + /*
> + * The supplicant cannot grow its buffer dynamically, so
> + * requeueing would retry this request forever. Complete it
> + * with a transport error and keep this ioctl waiting for the
> + * next request instead of terminating a supplicant worker.
> + */
> + mbedtee_supp_complete_req(req);
> + mutex_unlock(&supp->mutex);
> + continue;
> + }
> +
> + req->shm = shm;
> + *func = req->func;
> + memcpy(shm->kaddr, req->data, req->size);
> + param->u.memref.size = req->size;
> + mutex_unlock(&supp->mutex);
> +
> + return 0;
> + }
> +
> +err:
> + tee_shm_put(shm);
> + param->u.memref.shm = NULL;
> + return ret;
> +}
> +
> +/*
> + * Called by supplicant to send back the result of a request.
> + */
> +int mbedtee_supp_send(struct tee_context *ctx, u32 ret, u32 num_params,
> + struct tee_param *param)
> +{
> + struct tee_device *teedev = ctx->teedev;
> + struct mbedtee_device *mbedtee = tee_get_drvdata(teedev);
> + struct mbedtee_supp *supp = &mbedtee->supp;
> + struct mbedtee_supp_req *req;
> + struct mbedtee_supp_req *_req;
> + bool invalid;
> +
> + /*
> + * Find and detach the active request belonging to this worker thread
> + * and to this supplicant context. Each worker is identified by its
> + * task_struct pointer, which was recorded when supp_recv() dispatched
> + * the request.
> + */
> + mutex_lock(&supp->mutex);
> + req = NULL;
> + list_for_each_entry(_req, &supp->active_reqs, node) {
> + if (_req->worker == current && _req->ctx == ctx) {
> + req = _req;
> + list_del_init(&req->node);
> + break;
> + }
> + }
> + mutex_unlock(&supp->mutex);
> +
> + if (!req)
> + return -ENOENT;
> +
> + /*
> + * Complete the request even on malformed input: the worker waiting
> + * in mbedtee_supp_handler() must not hang because a broken
> + * supplicant sent invalid parameters.
> + */
> + invalid = num_params != 1 || !tee_param_is_memref(param) ||
> + param->u.memref.size > req->size;
> + if (invalid) {
> + if (req->data && req->size >= sizeof(struct supp_cmd_hdr))
> + ((struct supp_cmd_hdr *)req->data)->ret =
> + TEEC_ERROR_COMMUNICATION;
> + } else {
> + memcpy(req->data, req->shm->kaddr, param->u.memref.size);
> + }
> + if (req->shm)
> + tee_shm_put(req->shm);
> + req->shm = NULL;
> +
> + /* Wake up mbedtee_supp_handler(). */
> + complete(&req->c);
> +
> + return invalid ? -EINVAL : 0;
> +}
> diff --git a/include/uapi/linux/tee.h b/include/uapi/linux/tee.h
> index 5203977..2d30296 100644
> --- a/include/uapi/linux/tee.h
> +++ b/include/uapi/linux/tee.h
> @@ -60,6 +60,7 @@
> #define TEE_IMPL_ID_AMDTEE 2
> #define TEE_IMPL_ID_TSTEE 3
> #define TEE_IMPL_ID_QTEE 4
> +#define TEE_IMPL_ID_MBEDTEE 5
>
> /*
> * OP-TEE specific capabilities
> --
> 2.43.0
>
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