Re:RISC-V OS Using Rust: Memory Management Unit
by comex on Monday November 04, 2019 @04:48PM
(#21446876)
> Obviously, I wasn't consulted when this was kicked around, and I haven't done my due diligence to look up potential reasons. So, I risk embarrassment to preserve my time :(.
TL;DR: You're expected to still use the bits as access/dirty flags, but instead of the hardware automagically setting them, you set them yourself from the page fault handler. (Or if you don't need to track those things, you just set the flags to 1 from the start.)
If anyone's wondering, I explained the reason:
https://github.com/pavehawk2007/osblog/issues/11
TL;DR: You're expected to still use the bits as access/dirty flags, but instead of the hardware automagically setting them, you set them yourself from the page fault handler. (Or if you don't need to track those things, you just set the flags to 1 from the start.)