diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/design/firmware-design.rst | 7 | ||||
| -rw-r--r-- | docs/getting_started/user-guide.rst | 4 | ||||
| -rw-r--r-- | docs/plat/qemu_sbsa.rst | 48 |
3 files changed, 57 insertions, 2 deletions
diff --git a/docs/design/firmware-design.rst b/docs/design/firmware-design.rst index dc082082..2cbd9c94 100644 --- a/docs/design/firmware-design.rst +++ b/docs/design/firmware-design.rst @@ -2540,8 +2540,11 @@ Armv8.1-A This Architecture Extension is targeted when ``ARM_ARCH_MAJOR`` >= 8, or when ``ARM_ARCH_MAJOR`` == 8 and ``ARM_ARCH_MINOR`` >= 1. -- The Compare and Swap instruction is used to implement spinlocks. Otherwise, - the load-/store-exclusive instruction pair is used. +- By default, a load-/store-exclusive instruction pair is used to implement + spinlocks. The ``USE_SPINLOCK_CAS`` build option when set to 1 selects the + spinlock implementation using the ARMv8.1-LSE Compare and Swap instruction. + Notice this instruction is only available in AArch64 execution state, so + the option is only available to AArch64 builds. Armv8.2-A ~~~~~~~~~ diff --git a/docs/getting_started/user-guide.rst b/docs/getting_started/user-guide.rst index 6dad3105..e540fd06 100644 --- a/docs/getting_started/user-guide.rst +++ b/docs/getting_started/user-guide.rst @@ -817,6 +817,10 @@ Common build options reduces SRAM usage. Refer to `Library at ROM`_ for further details. Default is 0. +- ``USE_SPINLOCK_CAS``: Setting this build flag to 1 selects the spinlock + implementation variant using the ARMv8.1-LSE compare-and-swap instruction. + Notice this option is experimental and only available to AArch64 builds. + - ``V``: Verbose build. If assigned anything other than 0, the build commands are printed. Default is 0. diff --git a/docs/plat/qemu_sbsa.rst b/docs/plat/qemu_sbsa.rst new file mode 100644 index 00000000..e04a63c7 --- /dev/null +++ b/docs/plat/qemu_sbsa.rst @@ -0,0 +1,48 @@ +Trusted Firmware-A for QEMU SBSA target +======================================== + +Trusted Firmware-A (TF-A) implements the EL3 firmware layer for QEMU SBSA +Armv8-A. While running Qemu from command line, we need to supply two Flash +images. First Secure BootRom is supplied by -pflash argument. This Flash image +is made by EDK2 build system by composing BL1 and FIP. Second parameter for Qemu +is responsible for Non-secure rom which also given with -pflash argument and +contains of UEFI and EFI variables (also made by EDK2 build system). Semihosting +is not used + +When QEMU starts all CPUs are released simultaneously, BL1 selects a +primary CPU to handle the boot and the secondaries are placed in a polling +loop to be released by normal world via PSCI. + +BL2 edits the FDT, generated by QEMU at run-time to add a node describing PSCI +and also enable methods for the CPUs. + +Current limitations: + +- Only cold boot is supported +- No instructions for how to load a BL32 (Secure Payload) + +To build TF-A: + +:: + + git clone https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git tfa + cd tfa + export CROSS_COMPILE=aarch64-linux-gnu- + make PLAT=qemu_sbsa all fip + +Images will be placed at build/qemu_sbsa/release (bl1.bin and fip.bin). +Need to copy them into top directory for EDK2 compilation. + +:: + + cp build/qemu_sbsa/release/bl1.bin ../ + cp build/qemu_sbsa/release/fip.bin ../ + +Those images cannot be used by itself (no semihosing support). Flash images are built by +EDK2 build system, refer to edk2-platform repo for full build instructions. + +:: + + git clone https://github.com/tianocore/edk2-platforms.git + Platform/Qemu/SbsaQemu/Readme.md + |