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Lu wrote: > On Wed, Mar 9, 2022 at 7:17 AM Jan Beulich wrote: >> >> On 09.03.2022 16:08, H.J. 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 ... >> > > If there is a real issue, we should fix it without a command-line > option. Can you use the input section name/flags to check it? I don't see how - it's overwhelmingly likely all in .text. Jan