Re: [PATCH] objtool: Detect non-relocated text references

[Josh Poimboeuf]

On Fri, Oct 04, 2024 at 08:54:16AM +0200, Ard Biesheuvel wrote:
> On Fri, 4 Oct 2024 at 02:31, Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
> > However there are some "lea xxx(%rip)" cases which don't use relocations
> > because they're referencing code in the same translation unit.
> 
> input section

"in the same translation unit and section" ?

> > However if we enable -fpie, the compiler would start generating them and
> > there would definitely be bugs in the IBT sealing.
> >
> 
> -fpie is guaranteed to break things, but even without it, Clang may
> issue RIP-relative LEA instructions (or LLD when it performs
> relaxations), so this is definitely worth addressing even if we don't
> enable -fpie.

I haven't seen this with Clang either.  Also, objtool runs before the
linker so LLD relaxations shouldn't matter.

-- 
Josh