August 2026 - OP-TEE - lists.trustedfirmware.org

[PATCH v4 0/2] ufs: rpmb: make RPMB usable with OP-TEE key derivation

by Jorge Ramirez-Ortiz

This series makes UFS RPMB work out of the box with an OP-TEE that implements the standard eMMC RPMB key-derivation flow, without requiring any fundamental changes on the OP-TEE side. RPMB provides an authenticated, replay-protected storage area whose security relies on a secret authentication key. In our setup that key is never exposed to the kernel: OP-TEE derives it in the secure world from its hardware-unique key and a device identifier (dev_id) that the RPMB core hands down. OP-TEE's implementation targets eMMC, where dev_id is the 16-byte eMMC CID, and both the fixed length and the raw-CID layout are baked into its key derivation. Two things stand in the way of reusing that same, unmodified OP-TEE flow for UFS RPMB: 1. On a cold boot the very first frame sent to the RPMB well-known LU comes back with a power-on UNIT ATTENTION (ASC 0x29), which the SCSI core reports rather than retries. RPMB has no earlier guaranteed access that could clear the condition first, so RPMB fails on every power cycle. Patch 1 asks the SCSI core to retry the power-on UNIT ATTENTION on the RPMB WLUN. 2. The UFS RPMB id is "<device_id>-R<region>", which is variable length and longer than 16 bytes. Passing it verbatim would tie the derived key to a length OP-TEE does not expect and diverge from the fixed eMMC CID ABI. Patch 2 hashes it into a fixed 16-byte dev_id with blake2b, keeping the key stable and unique per region while matching the eMMC CID layout OP-TEE relies on. The hash algorithm and input string are thus part of the key-derivation ABI and must stay stable. With both patches, UFS RPMB is functional from the first access after a cold boot and derives keys through the existing eMMC-style OP-TEE flow, (requires minimal OP-TEE changes pending on the CID proposal done here). Tested on IQ-9075 with Open Firmware [1], pending OP-TEE changes [1]https://ldts.github.io/qcom-buildroot Dependencies: U-boot: https://lore.kernel.org/u-boot/20260720085202.537019-1-jorge.ramirez@oss.qu… OP-TEE: https://github.com/OP-TEE/optee_os/pull/7881 v4: * ufs: rpmb: retry power-on UNIT ATTENTION on the RPMB WLUN: open-code the power-on ASC 0x29 (with a naming comment) as the rest of the SCSI tree does, instead of a UFS_RPMB_ASC_POWER_ON define; add a UFS_RPMB_UA_RETRIES define for the retry count; reworded the commit message. * ufs: rpmb: use a fixed-length RPMB dev_id: reworded the commit message; no functional change. v3: * ufs: rpmb: use a fixed-length RPMB dev_id: hash into a stack buffer instead of a kzalloc'd one; rpmb_dev_register() copies dev_id, so the heap allocation and its cleanup were unnecessary. v2: * ufs: rpmb: replace blake2s with blake2b so that the same support can be added to u-boot (CRYPTO_LIB_BLAKE2B) * added links to U-boot and OP-TEE changes. v1: * ufs: rpmb: retry power-on UNIT ATTENTION on the RPMB WLUN: - fix using uses SCMD_FAILURE_ASC_ANY to retry any Unit Attention - fix unused variable * ufs: rpmb: use a fixed-length RPMB dev_id - fix selecting a non-existent Kconfig symbol Jorge Ramirez-Ortiz (2): ufs: rpmb: retry power-on UNIT ATTENTION on the RPMB WLUN ufs: rpmb: use a fixed-length RPMB dev_id drivers/ufs/Kconfig | 1 + drivers/ufs/core/ufs-rpmb.c | 29 ++++++++++++++++++++++++++--- 2 files changed, 27 insertions(+), 3 deletions(-) -- 2.54.0

2 months, 1 week

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[PATCH v3 0/2] ufs: rpmb: make RPMB usable with OP-TEE key derivation

by Jorge Ramirez-Ortiz

This series makes UFS RPMB work out of the box with an OP-TEE that implements the standard eMMC RPMB key-derivation flow, without requiring any fundamental changes on the OP-TEE side. RPMB provides an authenticated, replay-protected storage area whose security relies on a secret authentication key. In our setup that key is never exposed to the kernel: OP-TEE derives it in the secure world from its hardware-unique key and a device identifier (dev_id) that the RPMB core hands down. OP-TEE's implementation targets eMMC, where dev_id is the 16-byte eMMC CID, and both the fixed length and the raw-CID layout are baked into its key derivation. Two things stand in the way of reusing that same, unmodified OP-TEE flow for UFS RPMB: 1. On a cold boot the very first frame sent to the RPMB well-known LU comes back with a power-on UNIT ATTENTION (ASC 0x29), which the SCSI core reports rather than retries. RPMB has no earlier guaranteed access that could clear the condition first, so RPMB fails on every power cycle. Patch 1 asks the SCSI core to retry the power-on UNIT ATTENTION on the RPMB WLUN. 2. The UFS RPMB id is "<device_id>-R<region>", which is variable length and longer than 16 bytes. Passing it verbatim would tie the derived key to a length OP-TEE does not expect and diverge from the fixed eMMC CID ABI. Patch 2 hashes it into a fixed 16-byte dev_id with blake2b, keeping the key stable and unique per region while matching the eMMC CID layout OP-TEE relies on. The hash algorithm and input string are thus part of the key-derivation ABI and must stay stable. With both patches, UFS RPMB is functional from the first access after a cold boot and derives keys through the existing eMMC-style OP-TEE flow, (requires minimal OP-TEE changes pending on the CID proposal done here). Tested on IQ-9075 with Open Firmware [1], pending OP-TEE changes [1]https://ldts.github.io/qcom-buildroot Dependencies: U-boot: https://lore.kernel.org/u-boot/20260720085202.537019-1-jorge.ramirez@oss.qu… OP-TEE: https://github.com/OP-TEE/optee_os/pull/7881 v3: * ufs: rpmb: use a fixed-length RPMB dev_id: hash into a stack buffer instead of a kzalloc'd one; rpmb_dev_register() copies dev_id, so the heap allocation and its cleanup were unnecessary. v2: * ufs: rpmb: replace blake2s with blake2b so that the same support can be added to u-boot (CRYPTO_LIB_BLAKE2B) * added links to U-boot and OP-TEE changes. v1: * ufs: rpmb: retry power-on UNIT ATTENTION on the RPMB WLUN: - fix using uses SCMD_FAILURE_ASC_ANY to retry any Unit Attention - fix unused variable * ufs: rpmb: use a fixed-length RPMB dev_id - fix selecting a non-existent Kconfig symbol Jorge Ramirez-Ortiz (2): ufs: rpmb: retry power-on UNIT ATTENTION on the RPMB WLUN ufs: rpmb: use a fixed-length RPMB dev_id drivers/ufs/Kconfig | 1 + drivers/ufs/core/ufs-rpmb.c | 29 ++++++++++++++++++++++++++--- 2 files changed, 27 insertions(+), 3 deletions(-) -- 2.54.0

2 months, 2 weeks

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[PATCH v2] tee: qcomtee: fix kernel-doc warnings

by Babanpreet Singh

Fix kernel-doc issues present since the driver was added in commit d6e290837e50 ("tee: add Qualcomm TEE driver"): - async_release() documents its second parameter as @msg, but the parameter is named async_msg (msg is a local variable); - struct qcomtee_msg_object_invoke documents member @ctx, but the member is named cxt; - enum qcomtee_arg_type leaves QCOMTEE_ARG_TYPE_NR undescribed. The cxt spelling is part of the QTEE message format and is used throughout the driver; struct qcomtee_msg_callback in the same header already documents it as @cxt, so the comment is corrected rather than the member. No functional changes. Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver") Reviewed-by: Amirreza Zarrabi <amirreza.zarrabi(a)oss.qualcomm.com> Assisted-by: Claude:claude-opus-5 [kernel-doc] Signed-off-by: Babanpreet Singh <bbnpreetsingh(a)gmail.com> --- v2: - add the Fixes tag Jens asked for; no code changes - pick up Amirreza's Reviewed-by v1: https://lore.kernel.org/all/20260802003956.7-1-bbnpreetsingh@gmail.com/ drivers/tee/qcomtee/async.c | 4 ++-- drivers/tee/qcomtee/qcomtee_msg.h | 2 +- drivers/tee/qcomtee/qcomtee_object.h | 1 + 3 files changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/tee/qcomtee/async.c b/drivers/tee/qcomtee/async.c index 31bff4309e672..5849e51612033 100644 --- a/drivers/tee/qcomtee/async.c +++ b/drivers/tee/qcomtee/async.c @@ -97,10 +97,10 @@ static void qcomtee_get_async_buffer(struct qcomtee_object_invoke_ctx *oic, /** * async_release() - Process QTEE async release requests. * @oic: context used for the current invocation. - * @msg: async message for object release. + * @async_msg: async message for object release. * @size: size of the async buffer available. * - * Return: Size of the outbound buffer used when processing @msg. + * Return: Size of the outbound buffer used when processing @async_msg. */ static size_t async_release(struct qcomtee_object_invoke_ctx *oic, struct qcomtee_async_msg_hdr *async_msg, diff --git a/drivers/tee/qcomtee/qcomtee_msg.h b/drivers/tee/qcomtee/qcomtee_msg.h index 878f70178a5b6..5d7b21fdd3688 100644 --- a/drivers/tee/qcomtee/qcomtee_msg.h +++ b/drivers/tee/qcomtee/qcomtee_msg.h @@ -112,7 +112,7 @@ union qcomtee_msg_arg { /** * struct qcomtee_msg_object_invoke - Direct object invocation message. - * @ctx: object ID hosted in QTEE. + * @cxt: object ID hosted in QTEE. * @op: operation for the object. * @counts: number of different types of arguments in @args. * @args: array of arguments. diff --git a/drivers/tee/qcomtee/qcomtee_object.h b/drivers/tee/qcomtee/qcomtee_object.h index 8b4401ecad48c..d5de02dcef3b9 100644 --- a/drivers/tee/qcomtee/qcomtee_object.h +++ b/drivers/tee/qcomtee/qcomtee_object.h @@ -74,6 +74,7 @@ enum qcomtee_object_type { * @QCOMTEE_ARG_TYPE_OO: output object (OO). * @QCOMTEE_ARG_TYPE_IB: input buffer (IB). * @QCOMTEE_ARG_TYPE_IO: input object (IO). + * @QCOMTEE_ARG_TYPE_NR: number of argument types. * * Use the invalid type to specify the end of the argument array. */ base-commit: 2d2338c93da79b3bfe4b6099a931d9468d539952 -- 2.43.0

2 months, 2 weeks

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OP-TEE Contributions Forum, monthly meeting August 24

by Jens Wiklander

Hi, Tomorrow, Tuesday, it's time for another OP-TEE contributors' monthly meeting. For time and connection details, see the calendar at https://www.trustedfirmware.org/meetings/ Following up on some points from the last meeting: The OP-TEE 4.11.0 release is planned for October 16. We skipped the July 17 release earlier, so this release will be a bit larger than usual. During the last meeting, we discussed giving Etienne merge rights. He's already part of "THE REST" in the MAINTAINERS file, so this makes a lot of sense. It's also good to see how we can staff during holiday seasons. It would also be nice to have more people in "THE CORE REVIEWERS". Help reviewing vulnerability reports and their fixes is most welcome. We should probably take this offline. If someone can help review or even draft fixes, please drop me a note, and we'll figure out how to work together. Any other topics? Cheers, Jens

2 months, 2 weeks

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[PATCH v4 0/3] tee: add MbedTEE driver

by Xing Loong

This series adds a Linux TEE driver for MbedTEE, a Trusted Execution Environment for embedded systems (https://github.com/mbedtee). Two RPC transports are provided for systems where platform firmware or board configuration has already established the REE/TEE separation before Linux boots: - ARM/ARM64: SMC calls and GIC SPI notifications (TrustZone) - RISC-V: shared-memory ring buffers and IMSIC MSI notifications 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 for REE filesystem and RPMB operations. The series is structured as follows: [1/3] dt-bindings: vendor-prefixes: add mbedtee [2/3] dt-bindings: firmware: add mbedtee,tee binding [3/3] tee: add MbedTEE driver --- Changes in v4: - 0002: Move reserved-memory region descriptions into memory-region-names property (Rob) - 0002: Define memory-region-names item order at top level; keep per-branch name count constraints (maxItems: 2 / minItems: 3) (Rob) - 0003: 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 - Link to v3: https://lore.kernel.org/r/20260720073558.799755-1-xing.xl.loong@gmail.com/ Changes in v3: - 0002: Drop all phandle stub nodes from examples. - 0002: Remove redundant required: - interrupts from then branch. - 0002: Simplify title and description. - Link to v2: https://lore.kernel.org/r/20260702151115.544016-1-xing.xl.loong@gmail.com/ - Link to v1: https://lore.kernel.org/r/20260701132514.186953-1-xing.xl.loong@gmail.com/ Changes in v2: - 0002: Fix DT binding review comments from Krzysztof Kozlowski: - Drop $nodename, "YAML devicetree binding" wording, property descriptions - Rename compatible string to mbedtee,tee - Rename memory regions: rpc-t2r-ring -> t2r-ring, rpc-t2r-shm -> t2r-shm, rpc-r2t-ring -> r2t-ring - Add memory-region / memory-region-names to required - Simplify allOf constraints (drop redundant else-branch items) - Rewrite description to describe hardware/firmware, not the binding or driver - Drop all irrelevant platform nodes (gic, cpus, reserved-memory) - Add maxItems: 1 constraint to interrupts property (Sashiko AI review) - 0003: - 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 --- Xing Loong (3): dt-bindings: vendor-prefixes: add mbedtee dt-bindings: firmware: add mbedtee,tee binding tee: add MbedTEE driver .../bindings/firmware/mbedtee,tee.yaml | 102 +++ .../devicetree/bindings/vendor-prefixes.yaml | 2 + 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 + 22 files changed, 3499 insertions(+), 1 deletion(-) create mode 100644 Documentation/devicetree/bindings/firmware/mbedtee,tee.yaml 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 base-commit: 03e2778d1f11de9260543f969e9e888a1c2bf830 -- 2.43.0

2 months, 3 weeks

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[PATCH] tee: qcomtee: fix kernel-doc warnings

by Babanpreet Singh

Fix kernel-doc issues present since the driver was added in commit d6e290837e50 ("tee: add Qualcomm TEE driver"): - async_release() documents its second parameter as @msg, but the parameter is named async_msg (msg is a local variable); - struct qcomtee_msg_object_invoke documents member @ctx, but the member is named cxt; - enum qcomtee_arg_type leaves QCOMTEE_ARG_TYPE_NR undescribed. The cxt spelling is part of the QTEE message format and is used throughout the driver; struct qcomtee_msg_callback in the same header already documents it as @cxt, so the comment is corrected rather than the member. No functional changes. Assisted-by: Claude:claude-opus-5 [kernel-doc] Signed-off-by: Babanpreet Singh <bbnpreetsingh(a)gmail.com> --- drivers/tee/qcomtee/async.c | 4 ++-- drivers/tee/qcomtee/qcomtee_msg.h | 2 +- drivers/tee/qcomtee/qcomtee_object.h | 1 + 3 files changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/tee/qcomtee/async.c b/drivers/tee/qcomtee/async.c index 31bff4309e672..5849e51612033 100644 --- a/drivers/tee/qcomtee/async.c +++ b/drivers/tee/qcomtee/async.c @@ -97,10 +97,10 @@ static void qcomtee_get_async_buffer(struct qcomtee_object_invoke_ctx *oic, /** * async_release() - Process QTEE async release requests. * @oic: context used for the current invocation. - * @msg: async message for object release. + * @async_msg: async message for object release. * @size: size of the async buffer available. * - * Return: Size of the outbound buffer used when processing @msg. + * Return: Size of the outbound buffer used when processing @async_msg. */ static size_t async_release(struct qcomtee_object_invoke_ctx *oic, struct qcomtee_async_msg_hdr *async_msg, diff --git a/drivers/tee/qcomtee/qcomtee_msg.h b/drivers/tee/qcomtee/qcomtee_msg.h index 878f70178a5b6..5d7b21fdd3688 100644 --- a/drivers/tee/qcomtee/qcomtee_msg.h +++ b/drivers/tee/qcomtee/qcomtee_msg.h @@ -112,7 +112,7 @@ union qcomtee_msg_arg { /** * struct qcomtee_msg_object_invoke - Direct object invocation message. - * @ctx: object ID hosted in QTEE. + * @cxt: object ID hosted in QTEE. * @op: operation for the object. * @counts: number of different types of arguments in @args. * @args: array of arguments. diff --git a/drivers/tee/qcomtee/qcomtee_object.h b/drivers/tee/qcomtee/qcomtee_object.h index 8b4401ecad48c..d5de02dcef3b9 100644 --- a/drivers/tee/qcomtee/qcomtee_object.h +++ b/drivers/tee/qcomtee/qcomtee_object.h @@ -74,6 +74,7 @@ enum qcomtee_object_type { * @QCOMTEE_ARG_TYPE_OO: output object (OO). * @QCOMTEE_ARG_TYPE_IB: input buffer (IB). * @QCOMTEE_ARG_TYPE_IO: input object (IO). + * @QCOMTEE_ARG_TYPE_NR: number of argument types. * * Use the invalid type to specify the end of the argument array. */ -- 2.43.0

2 months, 3 weeks

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[PATCH v2] Documentation: Extend the real-time hardware bits with some firmware bits

by Sebastian Andrzej Siewior

I have been reviewing how OP‑TEE is implemented and how secure‑world invocations behave. The goal was to determine whether an OP‑TEE call can delay the Linux side and introduce latency depending on the time spent in the secure world. Similar latency effects are already known for EFI runtime services, but this was not documented. To mitigate the impact, EFI runtime invocations can be restricted to specific CPUs so that real‑time workloads on other CPUs remain unaffected. This mechanism, however, is only described in the commit that introduced it. This change adds a firmware section that documents these behaviours explicitly. It highlights cases where firmware can delay the kernel, information that may be unfamiliar to some users and surprising-or concerning-to others. Assisted-by: Microsoft-Copilot Signed-off-by: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de> --- v1…v2: https://lore.kernel.org/all/20260701091226.7SWW4TrT@linutronix.de - Rewrote the OP-TEE bits after some feedback from Ilias and Jens. Added a link to the TF-A/OP-TEE documentation. The main difference is that in contrast to my initial belief, OP-TEE can disable normal-world's interrupts and it is not guaranteed that normal world can always preempt the secure world. Documentation/core-api/real-time/hardware.rst | 104 ++++++++++++++++++ 1 file changed, 104 insertions(+) diff --git a/Documentation/core-api/real-time/hardware.rst b/Documentation/core-api/real-time/hardware.rst index 19f9bb3786e03..9f95e75e6aa18 100644 --- a/Documentation/core-api/real-time/hardware.rst +++ b/Documentation/core-api/real-time/hardware.rst @@ -130,3 +130,107 @@ https://github.com/Linutronix/RTC-Testbench. The goal of this project is to validate real-time network communication. It can be thought of as a "cyclictest" for networking and also serves as a starting point for application development. + +Firmware +-------- + +The firmware often plays a significant role in system operation because it can +perform tasks that the kernel cannot directly access, and in some cases it can +even preempt or intercept the kernel. + +A common example of firmware assisting the kernel is when it provides a generic +interface to a resource. Instead of accessing an RTC chip through an I2C host +controller, the kernel may query the firmware for the current time, and the +firmware then accesses the RTC behind the scenes. + +Firmware can also intercept kernel execution by providing services that +temporarily take control of the system. One example is memory scrubbing, where +the firmware periodically pauses the kernel, reads back portions of system +memory, and then returns control. During this time, the kernel is effectively +interrupted. +In contrast, some systems provide hardware-based memory scrubbing, which +operates independently of firmware or software. See +Documentation/edac/scrub.rst for details. + +If the kernel is intercepted for longer periods then these periods can be made +visible with the hardware latency detector. See +Documentation/trace/hwlat_detector.rst. + +The kernel can also be intercepted in response to specific events, such as +overheating. In this case, the firmware may throttle the CPU or shut it down +immediately to prevent hardware damage. + +Unless the firmware is well documented, it should be thoroughly tested to +uncover any unexpected behaviour. + +EFI +~~~~ + +EFI provides runtime services that act as a communication interface between the +firmware and the operating system. One such service is reading and writing EFI +variables, which are used, for example, to determine the boot source. + +Invoking a runtime service may require the architecture to disable kernel +preemption or interrupts during the call. This means the duration of a service +invocation directly affects the system’s observable latency. There is also +nothing that prevents a service call from disabling interrupts internally while +it runs. + +For these reasons, EFI runtime services are disabled by default on a PREEMPT_RT +kernel. They can still be enabled at boot time or via a Kconfig option if +required. +The native EFI runtime service implementation (where both the EFI service and +the kernel are either 32-bit or 64-bit executables) uses a wrapper mechanism +that invokes the service through a dedicated workqueue. This workqueue is named +efi_runtime, and it can be restricted to a housekeeping CPU using the +``/sys/devices/virtual/workqueue/efi_runtime/cpumask`` sysfs file. Assigning it +to a housekeeping CPU ensures that potentially long service invocations do not +impact the real-time workload which is restricted to other CPUs. + +It must also be verified that the runtime services behave as expected. Some +implementations on the x86 architecture pause all other CPUs while one CPU +performs the service call. In such cases, the interruption affects all CPUs, +and restricting the workqueue to a single CPU provides no benefit. + +OP-TEE (ARM) +~~~~~~~~~~~~ + +Execution flows from the normal world (Linux) into the secure world (OP-TEE) +through the secure monitor at EL3. The transition is initiated by the `smc` +(Secure Monitor Call) opcode or the `hvc` (Hypervisor Call) opcode together +with a function identifier. The calling convention defines two types of calls: +**yielding calls** and **fast calls**: + +- A **yielding call** unmasks interrupts before handling the requested service, + allowing normal world interrupts to occur. +- A **fast call** handles the requested service atomically, without allowing + interrupts from either the normal world or the secure world. + +In addition, the secure world (EL3 and OP-TEE) can receive interrupts routed to +the secure world. While a secure world interrupt is being serviced, +normal world interrupts are masked and cannot preempt the operation. + +The transition from normal world to secure monitor to OP-TEE and back introduces +additional latency due to world switching and context save/restore. This +overhead is typically a few microseconds and usually remains within the noise +floor. + +It is worth noting that the normal world cannot mask secure interrupts, while +the secure world can mask normal-world interrupts during execution. How OP-TEE +affects real-time workloads depends on whether secure interrupts are enabled +and which OP-TEE services are invoked. + +A practical concern is any fast call that runs longer than expected, for +example a function that occasionally performs a long-running cryptographic +computation. Another example that may block in an unexpected way are OP-TEE +drivers that issue RPC requests. An OP-TEE service in the secure world (RPMB +for instance) may need to issue a request back to the normal world (the Linux +driver) in order to complete the operation. While Linux remains preemptible, +the thread that issued the request stays blocked until the RPC completes and +the secure function call returns. + +The TF-A project provides documentation on interrupt management: +https://trustedfirmware-a.readthedocs.io/en/latest/design/interrupt-framework-design.html#interrupt-management-framework + +The OP-TEE project provides documentation on how interrupts are handled: +https://optee.readthedocs.io/en/latest/architecture/core.html#interrupt-handling -- 2.53.0

2 months, 4 weeks

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[GIT PULL] QCOMTEE update for v7.3

by Jens Wiklander

Hello soc maintainers, Please pull this small update for the QCOMTEE driver. Thanks, Jens The following changes since commit dc59e4fea9d83f03bad6bddf3fa2e52491777482: Linux 7.2-rc1 (2026-06-28 12:01:31 -0700) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/jenswi/linux-tee.git tags/qcomtee-for-v7.3 for you to fetch changes up to d92f87f3e7c79f58cc6d6edad4bf1c96f795aa7b: tee: qcomtee: Drop unused assignment of platform_device_id driver data (2026-06-29 07:53:26 +0200) ---------------------------------------------------------------- Drop unused assignment of platform_device_id driver data ---------------------------------------------------------------- Uwe Kleine-König (The Capable Hub) (1): tee: qcomtee: Drop unused assignment of platform_device_id driver data drivers/tee/qcomtee/call.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)

3 months

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[GIT PULL] OP-TEE fix for v7.2

by Jens Wiklander

Hello soc maintainers, Please pull this small OP-TEE fix for the OP-TEE drivers. Thanks, Jens The following changes since commit dc59e4fea9d83f03bad6bddf3fa2e52491777482: Linux 7.2-rc1 (2026-06-28 12:01:31 -0700) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/jenswi/linux-tee.git tags/optee-fix-for-v7.2 for you to fetch changes up to 650c88738ae8976f46ba71b24dd8aa311adc6fde: optee: ffa: Add NULL check in optee_ffa_lend_protmem (2026-06-29 08:04:45 +0200) ---------------------------------------------------------------- Add NULL check in optee_ffa_lend_protmem() ---------------------------------------------------------------- Mostafa Saleh (1): optee: ffa: Add NULL check in optee_ffa_lend_protmem drivers/tee/optee/ffa_abi.c | 3 +++ 1 file changed, 3 insertions(+)

3 months

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ufs: rpmb: make RPMB usable with OP-TEE key derivation

by Jorge Ramirez-Ortiz

This series makes UFS RPMB work out of the box with an OP-TEE that implements the standard eMMC RPMB key-derivation flow, without requiring any fundamental changes on the OP-TEE side. RPMB provides an authenticated, replay-protected storage area whose security relies on a secret authentication key. In our setup that key is never exposed to the kernel: OP-TEE derives it in the secure world from its hardware-unique key and a device identifier (dev_id) that the RPMB core hands down. OP-TEE's implementation targets eMMC, where dev_id is the 16-byte eMMC CID, and both the fixed length and the raw-CID layout are baked into its key derivation. Two things stand in the way of reusing that same, unmodified OP-TEE flow for UFS RPMB: 1. On a cold boot the very first frame sent to the RPMB well-known LU comes back with a power-on UNIT ATTENTION (ASC 0x29), which the SCSI core reports rather than retries. RPMB has no earlier guaranteed access that could clear the condition first, so RPMB fails on every power cycle. Patch 1 asks the SCSI core to retry the power-on UNIT ATTENTION on the RPMB WLUN. 2. The UFS RPMB id is "<device_id>-R<region>", which is variable length and longer than 16 bytes. Passing it verbatim would tie the derived key to a length OP-TEE does not expect and diverge from the fixed eMMC CID ABI. Patch 2 hashes it into a fixed 16-byte dev_id with blake2s, keeping the key stable and unique per region while matching the eMMC CID layout OP-TEE relies on. The hash algorithm and input string are thus part of the key-derivation ABI and must stay stable. With both patches, UFS RPMB is functional from the first access after a cold boot and derives keys through the existing eMMC-style OP-TEE flow, (requires minimal OP-TEE changes). Jorge Ramirez-Ortiz (2): ufs: rpmb: retry power-on UNIT ATTENTION on the RPMB WLUN ufs: rpmb: use a fixed-length RPMB dev_id drivers/ufs/Kconfig | 1 + drivers/ufs/core/ufs-rpmb.c | 41 ++++++++++++++++++++++++++++++++++--- 2 files changed, 39 insertions(+), 3 deletions(-)

3 months, 1 week

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OP-TEE August 2026