Linux on S31

[GrieferPig]

Just want to show that MMU linux on s31 is possible: https://github.com/GrieferPig/esp32-s31-linux

Both OpenSBI and Linux are patched to accomodate for S31's CLIC-centric (I presume?) interrupt architecture and XIP support. Not much are usable atm, but it reaches init and shell.

You can download the kernel, bootloader and OpenSBI on the Release page: https://github.com/GrieferPig/esp32-s31 ... ag/initial

Some outputs:

Code: Select all

~ # grep -E '^isa|^mmu' /proc/cpuinfo
isa             : rv32imafc_zicntr_zicsr_zifencei_zca_zcf_zbb
mmu             : sv32
~ # free -h
              total        used        free      shared  buff/cache   available
Mem:          14.7M        3.0M        8.9M           0        2.8M        8.2M
Swap:             0           0           0
~ # coremark | grep teration
Iterations/Sec   : 8.278146
Iterations       : 110

[hehongbo]

Holy shit, why are u so fast
I am still struggling with u-boot

[andylinpersonal]

For such an XIP kernel and constrained 16MiB device, we can skip u-boot entirely and jump into kernel from OpenSBI directly.
But u-boot may be useful to load a normal kernel from external device if later s31 SoC comes with larger PSRAM.

[eriksl]

How do you handle the (too) simple MMU v.s. the required virtual memory of Unix/Linux?

[Sprite]

How do you handle the (too) simple MMU v.s. the required virtual memory of Unix/Linux?

S31 has a fully-fledged Sv32 MMU.

[eriksl]

Yeah I read it one minute later! Nice!

[andylinpersonal]

Official Linux for S31 has been released !!