undefined instructions are expected to return SIGILL, while implemented
instructions that aren't available in CPL-3 are expected to SIGSEGV.
Noticed this while testing out CPU-Z, it installs a kernel module and
does a bunch of `RDMSR` and `OUTS` instructions. Decided to walk through
the rest of the instructions in the `System Instruction Reference`
section.
Turns out there's a bunch of oddities in there that we don't support.
First step is to go through all the explicitl SIGILL and SIGSEGV and
implement a test for them.
Next step will be implementing the remaining operations that are
considered "System" operations but are still available in CPL-3.
This list includes:
- lar
- lgdt
- lsl
- sidt
- sldt
- stac
- clac
- verr
- verw
Missed this instruction when implementing rdtscp. Returns the same ID
result in a register just like rdtscp, but without the cycle counter
results. Doesn't touch any flags just like rdtscp.
Reduces the ELF's VM size from 9.8MB down to 9.37MB and should reduce
initialization time a smidge.
Slammed this out while waiting for other PRs to get reviewed.
This has long since been unused. Originally implemented for some fuzzing
tests but has been abandoned and that should likely be implemented some
other way.
It is not an external component, and it makes paths needlessly long.
Ryan seemed amenable to this when we discussed on IRC earlier.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Ryan Houdek