Re: [PATCH v15 01/26] Documentation/x86: Add CET description

Yu, Yu-cheng
2020-11-30T19:48:31Z

On 11/30/2020 11:38 AM, Fāng-ruì Sòng wrote:
> On Mon, Nov 30, 2020 at 10:34 AM Yu, Yu-cheng <yu-cheng.yu@intel.com> wrote:
>>
>> On 11/30/2020 10:26 AM, Nick Desaulniers wrote:
>>> (In response to https://lore.kernel.org/lkml/20201110162211.9207-2-yu-cheng.yu@intel.com/)
>>>
>>>> These need to be enabled to build a CET-enabled kernel, and Binutils v2.31
>>>> and GCC v8.1 or later are required to build a CET kernel.
>>>
>>> What about LLVM? Surely CrOS might be of interest to ship this on (we ship the
>>> equivalent for aarch64 on Android).
>>>
>>
>> I have not built with LLVM, but think it probably will work as well. I
>> will test it.
>>
>>>> An application's CET capability is marked in its ELF header and can be
>>>> verified from the following command output, in the NT_GNU_PROPERTY_TYPE_0
>>>> field:
>>>>
>>>> readelf -n <application> | grep SHSTK
>>>> properties: x86 feature: IBT, SHSTK
>>>
>>> Same for llvm-readelf.
>>>
>>
>> I will add that to the document.
>>
>> Thanks,
>> Yu-cheng
>
> The baseline LLVM version is 10.0.1, which is good enough for clang
> -fcf-protection=full, llvm-readelf -n, LLD's .note.gnu.property
> handling (the LLD option is `-z force-ibt`, though)
>
>

Thanks!

Yu-cheng