sivionfive平台的编译，opensbi代码架构，程序分析

The RISC-V Supervisor Binary Interface (SBI) is the recommended interface between: A platform-specific firmware running in M-mode and a bootloader, a hypervisor or a general-purpose OS executing in S-mode or HS-mode. A hypervisor running in HS-mode and a bootloader or a general-purpose OS executing in VS-mode.