From c4d56d668f682f7d0d77a2e02f4728b1299f406e Mon Sep 17 00:00:00 2001 From: Patrick Rudolph Date: Mon, 5 Aug 2019 08:23:52 +0200 Subject: Documentation: Advertise support for OpenSBI MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Change-Id: Ie990bb95fcdcfab0246e8c694704022d9b8b5195 Signed-off-by: Patrick Rudolph Reviewed-on: https://review.coreboot.org/c/coreboot/+/34690 Tested-by: build bot (Jenkins) Reviewed-by: Jonathan Neuschäfer Reviewed-by: Philipp Hug Reviewed-by: Xiang Wang --- Documentation/arch/riscv/index.md | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) (limited to 'Documentation/arch/riscv/index.md') diff --git a/Documentation/arch/riscv/index.md b/Documentation/arch/riscv/index.md index 9a5de34f09..ea6a5cd47e 100644 --- a/Documentation/arch/riscv/index.md +++ b/Documentation/arch/riscv/index.md @@ -23,8 +23,20 @@ On entry to a stage or payload (including SELF payloads), ## Additional payload handoff requirements The location of cbmem should be placed in a node in the FDT. +## OpenSBI +In case the payload doesn't install it's own SBI, like the [RISCV-PK] does, +[OpenSBI] can be used instead. +It's loaded into RAM after coreboot has finished loading the payload. +coreboot then will jump to OpenSBI providing a pointer to the real payload, +which OpenSBI will jump to once the SBI is installed. + +Besides providing SBI it also sets protected memory regions and provides +a platform independent console. + +The OpenSBI code is always run in M mode. + ## Trap delegation -Traps are delegated in the ramstage. +Traps are delegated to the payload. ## SMP within a stage At the beginning of each stage, all harts save 0 are spinning in a loop on @@ -44,3 +56,6 @@ The hart blocks until fn is non-null, and then calls it. If fn returns, we will panic if possible, but behavior is largely undefined. Only hart 0 runs through most of the code in each stage. + +[RISCV-PK]: https://github.com/riscv/riscv-pk +[OpenSBI]: https://github.com/riscv/opensbi -- cgit v1.2.3