On Fri, May 18, 2018 at 11:46:54AM +0800, 王翔 wrote: [...]
Is coreboot's payload a bootloader running in m-mode ? If not, how does the SBI interrupt service be implemented ?
Previously, coreboot implemented the SBI, and launched the payload in S-mode. The SBI implementation implemented the old version of the SBI (a page mapped at a certain virtual address), so I removed it in commit 3ca8b598ed ("arch/riscv: Remove the current SBI implementation")[3]. The payload is still launched in S-mode, because noone has changed that.
So the new version of the SBI needs to be implemented.
There are two options:
1. Implement the new SBI in coreboot, and keep launching the payload in S-mode.
2. Implement the new SBI in a payload or some other kind of module, akin to ARM Trusted Firmware[1] or bbl[2]; Launch the code that implements the SBI in M-mode.
Jonathan Neuschäfer
[1]: https://github.com/ARM-software/arm-trusted-firmware/ [2]: https://github.com/riscv/riscv-pk/tree/master/bbl [3]: https://review.coreboot.org/cgit/coreboot.git/commit/?h=3ca8b598ed4ea16fd55d...