Re: [PATCH] x86: add 'runtime constant' infrastructure

[Linus Torvalds]

On Mon, 10 Jun 2024 at 18:09, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> Doing it in general is actually very very painful. Feel free to try -
> but I can almost guarantee that you will throw out the "Keep It Simple
> Stupid" approach and your patch will be twice the size if you do some
> "rewrite the whole instruction" stuff.
>
> I really think there's a fundamental advantage to keeping things simple.

I guess the KISS approach would be to have a debug mode that just adds
an 'int3' instruction *after* the constant. And then the constant
rewriting rewrites the constant and just changes the 'int3' into the
standard single-byte 'nop' instruction.

That wouldn't be complicated, and the cost would be minimal. But I
don't see it being worth it, at least not for the current use where
the unrewritten constant will just cause an oops on use.

                Linus