[PATCH, BFD, LD, AArch64, 0/4] Add support for AArch64 BTI and PAC in the linker
Nick Clifton
nickc@redhat.com
Mon Mar 11 12:30:00 GMT 2019
Hi Sudi,
>>>> does -z ibt warn on x86_64?
>>>
>>> No - it does not.Â
>> Maybe that comes automatically from the compiler driver though a quick
>> grep doesn't find me anything in the x86 backend.
Hmm, true - I cannot find it either.
> My understanding on this is a bit different though! Take
> property-x86-ibt4.d test for example where a source without IBT note is
> linked with -z ibt and it gives out an IBT note (and no error/warning).
> Have I missed something?
Nope, it must be me.
>>> Â * With --bti specified, BTI is enabled in the output provided that
>>>    the BTI note was found in all of the input files. If one or more
>> I feel this option is superfluous.
Hmm, OK,
> I agree that --force-bti looks like a more appropriate name for the
> option. I am open to the idea of dropping --bti-nowarn
> (--force-bti-nowarn) assuming that if need be, users can ignore the
> warnings and go on doing what they want anyway.
>
> @Nick, I hope that even though staying co-ordinated with x86_64 is
> desirable (to me as well in my personal opinion), our reasoning on the
> differences is convincing enough!
It is. :-)
OK, lets go with enabling BTI automatically, providing that all of
the inputs have the required notes. The --force-bti option does
what it says, but generates warnings for any input that does not
have a note.
I still think that --force-bti-nowarn would be a dangerous option
to have, but if your toolchain guys really think that it is necessary
then I am not going to object to it any longer.
Patch series with the revised option name(s) approved.
Cheers
Nick
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