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Lu wrote: > On Wed, Mar 9, 2022 at 6:39 AM Jan Beulich wrote: >> >> On 09.03.2022 15:27, H.J. Lu wrote: >>> On Wed, Mar 9, 2022 at 12:21 AM Jan Beulich wrote: >>>> On 04.03.2022 15:18, H.J. Lu wrote: >>>>> On Fri, Mar 04, 2022 at 02:34:58PM +0100, Jan Beulich wrote: >>>>>> --- a/ld/ld.texi >>>>>> +++ b/ld/ld.texi >>>>>> @@ -1372,6 +1372,12 @@ missing properties in input files. @opt >>>>>> the linker issue an error for missing properties in input files. >>>>>> Supported for Linux/x86_64. >>>>>> >>>>>> +@item lax-pcrel-relocs >>>>>> +Relax relocation overflow checks for certain 32-bit PC-relative relocations >>>>>> +which, when used by 32-bit code inside a 64-bit object, may require a >>>>>> +larger range of values to be considered valid. >>>>>> +Supported for x86-64 ELF targets. >>>>>> + >>>>> >>>>> I think the check should be turned on automatically. Can you use a GNU >>>>> property bit to tell linker that a larger range of values should be >>>>> checked for R_X86_64_PC32 >>>> >>>> I'm not convinced that would be desirable - the relaxed checking, after >>>> all, also affects relocations to 64-bit mode. Hence certain overflows >>>> won't be detected anymore. Therefore I'd expect people to make use of >>>> the new option only if they really have any affected relocations in >>>> 32-bit code. Additionally there's no way I can see to set such a >>>> property indicator when encountering the relocations in question only >>>> in data definitions, unless you wanted to tie the setting of the >>>> indicator to the mere use of .code{16,32} anywhere in the source (which >>>> would feel way to aggressive to me). IMO this level of control can only >>>> be achieved via command line option (without (a) becoming much more >>>> intrusive or (b) introducing new relocation types). >>> >>> A new relocation type sounds better. >> >> We've been there before with PC16 - there are enough arguments against >> introducing new types. I also never had the intention to propose ABI >> extensions. >> > > A command-line option isn't user friendly. On the other hand, why > now? The issue has been there forever. Because earlier on no-one cared to think about the issue? This really should have been considered when the ABI was initially written. _That_ would then also have been the time to introduce separate relocation types. Now we need to apply workarounds ... Jan