Re: [PATCH v5 15/22] objtool: Add action to check for absence of absolute relocations

[Peter Zijlstra]

On Wed, Jul 16, 2025 at 08:26:55PM +1000, Ard Biesheuvel wrote:

> For robustness, we should actually check for all absolute relocations
> here, including R_X86_64_32S, which is not abstracted into a R_ABSxx
> type for objtool.
> 
> So perhaps this needs an arch hook where x86_64 can implement it as
> 
> bool arch_is_abs_reloc(reloc)
> {
>    switch (reloc_type(reloc)) {
>    case R_X86_64_32:
>    case R_X86_64_32S:
>    case R_X86_64_64:
>       return true;
>    }
>    return false;
> }
> 
> and the default just compares against R_ABS32 / R_ABS64 depending on
> the word size?

Yes, an arch hook like that makes sense. Perhaps make the signature:

bool arch_is_abs_reloc(struct elf *, struct reloc *);

Because the word size comes from elf_addr_size().