4 ms·
> Could this a debugging instruction Highly unlikely. It's an actual vector instruction that you would otherwise use. The problem is it bypasses page table p
by akira2501 2y ago
> Could this a debugging instruction
Highly unlikely. It's an actual vector instruction that you would otherwise use. The problem is it bypasses page table protections when invoked with memory operands. There is no debugging utility in this mechanism.
- dpeckett 2y agoSecondly the extension is explicitly marked as experimental and is disabled on pretty much all kernel builds. Some of these platforms are incredibly janky atm, so I'm not at all surprised that something like this could slip through. The real surprise is scaleway rushing them into production.
- devit 2y agoIt seems it's an invalid encoding if I understand the article correctly. There seems to be some debugging utility in such a mechanism, e.g. you could use it to run CPU tests, benchmarks or debug code in userspace of a stock OS and then directly communicate with serial port MMIO without needing to pollute the CPU state with a system call or change the kernel to directly map the MMIO into userspace.