3 ms·
The RISC-V ISA specifically allows for custom extensions. Unfortunately, the licensing model does require the implementations to be FLOSS. This encourages crea
by goodpoint 5y ago
The RISC-V ISA specifically allows for custom extensions.
Unfortunately, the licensing model does require the implementations to be FLOSS. This encourages creating a lot of closed stuff with different and incompatible extensions.
- rjsw 5y agoWhether RISC-V ISA extensions are allowed or not is unrelated to the problems seen with ARM SoCs putting peripheral devices at different addresses.
- a9h74j 5y agoCould a device table [for on-chip peripherals] be put right on chip?
- formerly_proven 5y agoYes, that's a devicetree. Those can be tacked onto the kernel image or dynamically loaded from the chip's firmware (which most likely gets it from the firmware flash).
- goodpoint 5y agoSure, but the question was about diversity explosion in general.
- brucehoult 5y agoIt doesn't matter. As long as they implement the core RV64GC instruction set correctly, standard software will run, and if they implement privileged architecture 1.10 or later correctly then the standard Linux kernel will run. Vendors are free to use custom extensions to implement the bootloader and SBI. Normal code and even the OS won't see that. They can also use custom extensions in hardware drivers. Even in libc, if they want, though that gives more maintenance work.