mirror of
https://github.com/ARM-software/arm-trusted-firmware.git
synced 2025-04-26 14:55:16 +00:00
No description
c2d32a5f85
For SoCs which do not implement RAS, use DSB as a barrier to synchronize pending external aborts at the entry and exit of exception handlers. This is needed to isolate the SErrors to appropriate context. However, this introduces an unintended side effect as discussed in the https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/3440 A summary of the side effect and a quick workaround is provided as part of this patch and summarized here: The explicit DSB at the entry of various exception vectors in BL31 for handling exceptions from lower ELs can inadvertently trigger an SError exception in EL3 due to pending asyncrhonouus aborts in lower ELs. This will end up being handled by serror_sp_elx in EL3 which will ultimately panic and die. The way to workaround is to update a flag to indicate if the exception truly came from EL3. This flag is allocated in the cpu_context structure. This is not a bullet proof solution to the problem at hand because we assume the instructions following "isb" that help to update the flag (lines 100-102 & 139-141) execute without causing further exceptions. Change-Id: I4d345b07d746a727459435ddd6abb37fda24a9bf Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com> |
||
|---|---|---|
| bl1 | ||
| bl2 | ||
| bl2u | ||
| bl31 | ||
| bl32 | ||
| common | ||
| docs | ||
| drivers | ||
| fdts | ||
| include | ||
| lib | ||
| make_helpers | ||
| plat | ||
| services | ||
| tools | ||
| .checkpatch.conf | ||
| .editorconfig | ||
| .gitignore | ||
| .gitreview | ||
| dco.txt | ||
| license.rst | ||
| Makefile | ||
| readme.rst | ||
Trusted Firmware-A ================== Trusted Firmware-A (TF-A) is a reference implementation of secure world software for `Arm A-Profile architectures`_ (Armv8-A and Armv7-A), including an Exception Level 3 (EL3) `Secure Monitor`_. It provides a suitable starting point for productization of secure world boot and runtime firmware, in either the AArch32 or AArch64 execution states. TF-A implements Arm interface standards, including: - `Power State Coordination Interface (PSCI)`_ - `Trusted Board Boot Requirements CLIENT (TBBR-CLIENT)`_ - `SMC Calling Convention`_ - `System Control and Management Interface (SCMI)`_ - `Software Delegated Exception Interface (SDEI)`_ The code is designed to be portable and reusable across hardware platforms and software models that are based on the Armv8-A and Armv7-A architectures. In collaboration with interested parties, we will continue to enhance TF-A with reference implementations of Arm standards to benefit developers working with Armv7-A and Armv8-A TrustZone technology. Users are encouraged to do their own security validation, including penetration testing, on any secure world code derived from TF-A. More Info and Documentation --------------------------- To find out more about Trusted Firmware-A, please `view the full documentation`_ that is available through `trustedfirmware.org`_. -------------- *Copyright (c) 2013-2019, Arm Limited and Contributors. All rights reserved.* .. _Armv7-A and Armv8-A: https://developer.arm.com/products/architecture/a-profile .. _Secure Monitor: http://www.arm.com/products/processors/technologies/trustzone/tee-smc.php .. _Power State Coordination Interface (PSCI): PSCI_ .. _PSCI: http://infocenter.arm.com/help/topic/com.arm.doc.den0022d/Power_State_Coordination_Interface_PDD_v1_1_DEN0022D.pdf .. _Trusted Board Boot Requirements CLIENT (TBBR-CLIENT): https://developer.arm.com/docs/den0006/latest/trusted-board-boot-requirements-client-tbbr-client-armv8-a .. _SMC Calling Convention: http://infocenter.arm.com/help/topic/com.arm.doc.den0028b/ARM_DEN0028B_SMC_Calling_Convention.pdf .. _System Control and Management Interface (SCMI): SCMI_ .. _SCMI: http://infocenter.arm.com/help/topic/com.arm.doc.den0056a/DEN0056A_System_Control_and_Management_Interface.pdf .. _Software Delegated Exception Interface (SDEI): SDEI_ .. _SDEI: http://infocenter.arm.com/help/topic/com.arm.doc.den0054a/ARM_DEN0054A_Software_Delegated_Exception_Interface.pdf .. _Arm A-Profile architectures: https://developer.arm.com/architectures/cpu-architecture/a-profile .. _view the full documentation: https://www.trustedfirmware.org/docs/tf-a .. _trustedfirmware.org: http://www.trustedfirmware.org