On 28 April 2020 17:14:49 BST, Peter Zijlstra <pet...@infradead.org> wrote:
>On Tue, Apr 28, 2020 at 02:41:33PM +0100, Andrew Cooper wrote:
>> Its fine to focus on userspace first, but the kernel is far more
>simple.
>>
>> Looking at that presentation, the only thing missing for kernel is
>the
>> notrack thunks, in the unlikely case that such code would be
>tolerated
>> (Frankly, I don't expect Xen or Linux to run with notrack enabled, as
>> there is no legacy code to be concerned with).
>
>Uhhh.. ftrace and kretprobes play dodgy games with the
>return stack, doesn't that make the CET thing slightly more
>interesting?
Sure, there is work to do to enable CET. But Andy's point is that we
deliberately fixed up retpoline to be register-based *specifically* for the
purpose of being CET-compatible, so it's somewhat daft for GCC to be claiming
they are incompatible.
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
