November 2024 - OP-TEE - lists.trustedfirmware.org

[PATCH RFC 0/3] Introduce orphan tee_shm and default tee_context

by Amirreza Zarrabi

The TEE subsystem manages three main structures: tee_device, the device that represents the TEE; tee_context, the context that represents the TEE client; and tee_shm, which represents the shared memory with the TEE. When a tee_device is opened, it creates a tee_context instance. The tee_shm is created for the tee_device when allocating shared memory with the TEE but is linked to a context. The lifespan of the device is determined by the presence of context and shared memory, while the lifespan of a context depends on the client closing the device. This behavior has been modified, making the lifespan of context dependent on shared memory. If a client closes the device but doesn’t release the shared memory, the linked context will remain active, preventing the release callback from freeing resources in the TEE. This could lead to a deadlock if the TEE holds a reference to the shared memory and relies on the release callback to remove the reference. In this pachset we introduce orphan tee_shm and default tee_context. When a shared memory becomes orphan because its associated context is released, it no longer has a tee_context. One method to differentiate between orphaned and regular shared memory is to use NULL as the linked context. However, this can cause issues if releasing the shared memory triggers additional calls, like those to the supplicant, which require a valid context. Instead of using NULL, an internal tee_context for the driver can be used. The driver relies on tee_device_unregister which is a blocking calls waiting for all context to be released and all shared memory to be freed before unloading the driver. This means that all contexts, including internal context, should be closed before tee_device_unregister can proceed. This can introduce a short window where there is no valid context to use when releasing the shared memory. The default tee_context has lifespan similar to the device. For an orphan tee_shm, default context is used. This has not been tested. Looking for feedback if this is a reasonable change. Signed-off-by: Amirreza Zarrabi <quic_azarrabi(a)quicinc.com> --- Amirreza Zarrabi (3): tee: revert removal of redundant teedev in struct tee_shm tee: revert removal of linked list of struct tee_shm tee: introduce orphan tee_shm and default context drivers/tee/optee/core.c | 2 +- drivers/tee/optee/ffa_abi.c | 2 +- drivers/tee/optee/smc_abi.c | 2 +- drivers/tee/tee_core.c | 84 +++++++++++++++++++++++++++++---------------- drivers/tee/tee_private.h | 3 -- drivers/tee/tee_shm.c | 41 ++++++++++++---------- include/linux/tee_core.h | 15 ++++++++ include/linux/tee_drv.h | 13 ++++--- 8 files changed, 100 insertions(+), 62 deletions(-) --- base-commit: ae58226b89ac0cffa05ba7357733776542e40216 change-id: 20241120-fix-tee_shm-refcount-upstream-c671b89fbe67 Best regards, -- Amirreza Zarrabi <quic_azarrabi(a)quicinc.com>

3 hours, 44 minutes

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[PATCH v13 0/7] Introduction of a remoteproc tee to load signed firmware

by Arnaud Pouliquen

Main updates from version V12[1]: Fix warning build by fixing the inline declaration in remoteproc_tee.h (when CONFIG_REMOTEPROC_TEE is not set). Reported-by: kernel test robot <lkp(a)intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202410262040.PWNrKv2Q-lkp@intel.com/ Main updates from version V11[2]: - rename structures, functions, and variables from "tee_rproc_xxx" to "rproc_tee_xxx", - update rproc_tee_register to return an error instead of "struct rproc_tee *" pointer [1] https://lore.kernel.org/lkml/20241025205924.2087768-1-arnaud.pouliquen@foss… [2] https://lore.kernel.org/lkml/ZxZ4cBilIlpf3IPw@p14s/T/ Tested-on: commit 42f7652d3eb5 ("Linux 6.12-rc4") Description of the feature: -------------------------- This series proposes the implementation of a remoteproc tee driver to communicate with a TEE trusted application responsible for authenticating and loading the remoteproc firmware image in an Arm secure context. 1) Principle: The remoteproc tee driver provides services to communicate with the OP-TEE trusted application running on the Trusted Execution Context (TEE). The trusted application in TEE manages the remote processor lifecycle: - authenticating and loading firmware images, - isolating and securing the remote processor memories, - supporting multi-firmware (e.g., TF-M + Zephyr on a Cortex-M33), - managing the start and stop of the firmware by the TEE. 2) Format of the signed image: Refer to: https://github.com/OP-TEE/optee_os/blob/master/ta/remoteproc/src/remoteproc… 3) OP-TEE trusted application API: Refer to: https://github.com/OP-TEE/optee_os/blob/master/ta/remoteproc/include/ta_rem… 4) OP-TEE signature script Refer to: https://github.com/OP-TEE/optee_os/blob/master/scripts/sign_rproc_fw.py Example of usage: sign_rproc_fw.py --in <fw1.elf> --in <fw2.elf> --out <signed_fw.sign> --key ${OP-TEE_PATH}/keys/default.pem 5) Impact on User space Application No sysfs impact. The user only needs to provide the signed firmware image instead of the ELF image. For more information about the implementation, a presentation is available here (note that the format of the signed image has evolved between the presentation and the integration in OP-TEE). https://resources.linaro.org/en/resource/6c5bGvZwUAjX56fvxthxds Arnaud Pouliquen (7): remoteproc: core: Introduce rproc_pa_to_va helper remoteproc: Add TEE support remoteproc: core: Refactor resource table cleanup into rproc_release_fw remoteproc: Introduce release_fw optional operation dt-bindings: remoteproc: Add compatibility for TEE support remoteproc: stm32: Create sub-functions to request shutdown and release remoteproc: stm32: Add support of an OP-TEE TA to load the firmware .../bindings/remoteproc/st,stm32-rproc.yaml | 58 +- drivers/remoteproc/Kconfig | 10 + drivers/remoteproc/Makefile | 1 + drivers/remoteproc/remoteproc_core.c | 72 ++- drivers/remoteproc/remoteproc_tee.c | 510 ++++++++++++++++++ drivers/remoteproc/stm32_rproc.c | 139 +++-- include/linux/remoteproc.h | 8 + include/linux/remoteproc_tee.h | 105 ++++ 8 files changed, 848 insertions(+), 55 deletions(-) create mode 100644 drivers/remoteproc/remoteproc_tee.c create mode 100644 include/linux/remoteproc_tee.h base-commit: 42f7652d3eb527d03665b09edac47f85fb600924 -- 2.25.1

1 day, 22 hours

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Dynamic shared memory

by Patryk

Hello, I've been currently looking at the possibility of storing u-boot environment variables in RPMB and I've stumbled upon this article: https://www.linaro.org/blog/protected-uefi-variables-with-u-boot/ which briefly describes what needs to be done in order to achieve this. Unfortunately there is no comment section in this article so I cannot ask the author so I decided to try here. The article mentions that for that purpose, my board should support dynamic shared memory, therefore the OP-TEE port for my board should register that memory in platform main using the "register_ddr" function. For my platform (ls1028ardb) I do not see anything like this, thus I assume it's not supported. However, I'm wondering - is it my platform's hardware limitation or missing software implementation? Making this question more generic - does dynamic shared memory depend on hardware, meaning that there is no way to register dynamic shared memory if hardware does not support some particular features? I would be grateful for some hints. Best regards Patryk

2 days, 1 hour

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tee-supplicant priority

by Matteo Facchinetti

Hi, I have a doubt about the correct priority that tee-supplicant should have in the system. In detail, we have 2 user-space applications (user-pkcs11-0, user-pkcs11-1) that use the same PKCS11 services from OPTEE-OS (access to RPDB partition for private key). For project reason we use the following nice priority values: user-pkcs11-0, nice=-5 user-pkcs11-1, nice=-10 .... tee-supplcant, nice=0 ... a lot of other services with nice=0 ... Unfortunately, in some strange case when CPU is overload (booting).... appear a strange problem in user-pkcs11-1: occasionally the time for the certificate's signature check explode to 400ms. Due to the problem to replicate this defect, I have try to investigate in theory if could be verify a starvation/race-condition between tee-supplicant and user-pkcs11-1 or other-services. In this scenario, what is the correct priority value that tee-supplicant should have? I suspect that we should change the priority of tee-supplcant = user-pkcs11-1 = -10 Is it make sense for you, or maybe better to search the problem from an other side :-) ? Thanks in advance for your attention BR Matteo Facchinetti

5 days, 7 hours

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optee-based efi runtime variable service on TI j784s4 platforms

by Enric Balletbo i Serra

Hi all, I'm looking for any advice/clue to help me to progress on enabling TEE-base EFI Runtime Variable Service on TI a j784s4 platforms. I basically followed the steps described in u-boot documentation [1], I enabled some debugging messages but I think I'm at the point that the problem might be in the StandaloneMM application, and I'm not sure how to debug it. What I see is that when I run the tee-supplicant daemon, it looks like the tee_client_open_session() call loops forever and the tee_stmm_efi driver never ends to probe. With debug enabled I got the following messages. # tee-supplicant D/TC:? 0 tee_ta_init_session_with_context:557 Re-open trusted service 7011a688-ddde-4053-a5a9-7b3c4ddf13b8 D/TC:? 0 load_stmm:297 stmm load address 0x40004000 D/TC:? 0 spm_handle_scall:859 Received FFA version D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request D/TC:? 0 spm_handle_scall:867 Received FFA direct request And tracing the function calls gives me that: tee_stmm_efi_probe() { tee_client_open_context() { optee_get_version() { tee_get_drvdata(); (ret=0xffff000002e55800) } (ret=0xd) tee_ctx_match(); (ret=0x1) optee_smc_open() { tee_get_drvdata(); (ret=0xffff000002e55800) optee_open() { tee_get_drvdata(); (ret=0xffff000002e55800) } (ret=0x0) } (ret=0x0) } (ret=0xffff000004e71c80) tee_client_open_session() { optee_open_session() { tee_get_drvdata(); (ret=0xffff000002e55800) optee_get_msg_arg() { tee_get_drvdata(); (ret=0xffff000002e55800) tee_shm_get_va(); (ret=0xffff000002909000) } (ret=0xffff000002909000) tee_session_calc_client_uuid(); (ret=0x0) optee_to_msg_param(); (ret=0x0) optee_smc_do_call_with_arg() { tee_get_drvdata(); (ret=0xffff000002e55800) tee_shm_get_va(); (ret=0xffff000002909000) tee_shm_get_va(); (ret=0xffff000002909060) optee_cq_wait_init(); (ret=0xffff000002e55910) optee_smccc_smc(); (ret=0xffff0004) tee_get_drvdata(); (ret=0xffff000002e55800) optee_smccc_smc(); (ret=0xffff0004) tee_get_drvdata(); (ret=0xffff000002e55800) optee_smccc_smc(); (ret=0xffff0004) tee_get_drvdata(); (ret=0xffff000002e55800) optee_smccc_smc(); (ret=0xffff0004) tee_get_drvdata(); (ret=0xffff000002e55800) optee_smccc_smc(); (ret=0xffff0004) ... continues sending this forever ... ... Hit ^C to stop recording ... tee_get_drvdata(); (ret=0xffff000002e55800) optee_smccc_smc() { [1] https://docs.u-boot.org/en/latest/develop/uefi/uefi.html#using-op-tee-for-e… Thanks in advance, Enric

1 week, 3 days

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Linux user-level implementation of OP-TEE

by Jork Loeser (he/him)

Hello, I am Jork Loeser from Microsoft, and we are looking into providing the OP-TEE internal core API from Linux user-level, as well as hosting a derivative of OP-TEE OS in Linux user-level. Can you say is something like this has been attempted in the past, and perhaps provide pointers? How interesting would it be for OP-TEE to have such an implementation - e.g., for early/rapid-development purposes? Best, Jork

1 week, 3 days

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OP-TEE November 2024