Re: [PATCH] arch: x86: power: cpu: init %gs before __restore_processor_state (clang)

[Roman Kiryanov]

On Tue, Sep 15, 2020 at 10:46 AM Borislav Petkov <bp@xxxxxxxxx> wrote:

Hi Borislav, thank you for a quick response.

> Ok, google guys, pls make sure you Cc LKML too as this is where *all*
> patches and discussions are archived. Adding it now to Cc.

Thank you, I did not know this.

> Ok, so why is the kernel supposed to take yet another ugly workaround
> because there's a bug in the compiler?

I believe the kernel makes a questionable assumption on how clang
uses registers (gs will not be used if stack protection is disabled).
Both kernel and clang behaves unfortunate here.

> disable LTO

CFI depends on LTO.