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author | Atish Patra <atish.patra@wdc.com> | 2020-04-17 04:56:31 +0300 |
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committer | Anup Patel <anup@brainfault.org> | 2020-04-17 07:02:06 +0300 |
commit | 615587c336091140a515ff59fed932a2100814c2 (patch) | |
tree | 1cec0be10c905d7c186dabd135de20d7f5bcc847 /README.md | |
parent | 6c7922e23b85bef624ef84a8b05ed89495e1eb20 (diff) | |
download | opensbi-615587c336091140a515ff59fed932a2100814c2.tar.xz |
docs: Update README about supported SBI versions
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Diffstat (limited to 'README.md')
-rw-r--r-- | README.md | 21 |
1 files changed, 21 insertions, 0 deletions
@@ -39,6 +39,27 @@ OpenSBI also provides several runtime firmware examples built using the platform *riscv-pk* bootloader (aka BBL) and enable the use of well-known bootloaders such as [U-Boot] (https://git.denx.de/u-boot.git). +Supported SBI version +--------------------- +Currently, OpenSBI fully supports SBI specification *v0.2*. OpenSBI also +supports Hart State Management (HSM) SBI extension starting from OpenSBI v0.7. +HSM extension allows S-mode software to boot all the harts a defined order +rather than legacy method of random booting of harts. As a result, many +required features such as CPU hotplug, kexec/kdump can also be supported easily +in S-mode. HSM extension in OpenSBI is implemented in a non-backward compatible +manner to reduce the maintenance burden and avoid confusion. That's why, any +S-mode software using OpenSBI will not be able to boot more than 1 hart if HSM +extension is not supported in S-mode. + +Linux kernel already supports SBI v0.2 and HSM SBI extension starting from +**v5.7-rc1**. If you are using an Linux kernel older than **5.7-rc1** or any +other S-mode software without HSM SBI extension, you should stick to OpenSBI +v0.6 to boot all the harts. For a UMP systems, it doesn't matter. + +N.B. Any S-mode boot loader (i.e. U-Boot) doesn't need to support HSM extension, +as it doesn't need to boot all the harts. The operating system should be +capable enough to bring up all other non-booting harts using HSM extension. + Required Toolchain ------------------ |