buildroot bump to 2021.05-rc1, kernel.org linux 5.10.7, port for cva6…

Created by: eyssartk

This new version of cva6-sdk updates buildroot with the 2021.05-rc1 to support 32 bits RISC-V. I couldn't find the appropriate commit from the https://github.com/torvalds/linux so I used the kernel.org stable and use the patches at compile time.

The 32 or 64 bits configuration is set in the XLEN variable of the Makefile. It uses the 32 or 64 bits version of files in the configs folder.

Building with:

make all images

Tools and linux images will be located in install$(XLEN).

Status:

• 32bits version :
  • Working on Genesys with bitstream cva6 reorg 3ddf797
  • Booting but does not answer to terminal on Spike
• 64bits version :
  • Working on Genesys with bitstream cva6 reorg 3ddf797
  • Working on Spike