On Tue 2020-09-15 11:36:13, Roman Kiryanov wrote: > On Tue, Sep 15, 2020 at 11:27 AM Borislav Petkov <[email protected]> wrote: > > > 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. > > > > If the kernel is at fault here and this same thing happens with GCC, > > sure, but this is a clang-specific fix. > > This is fair. Unfortunately I am not an x86 asm expert. I expect the proper > fix should land into arch/x86/kernel/acpi/wakeup_64.S to init %gs > (maybe some more registers) before "jmp restore_processor_state".
That would certainly be nicer / more acceptable solution than patch
being proposed here.
Code was written with assumption compiler random C code would not use
%gs. If that's no longer true, fixing it in wakeup_64.S _with comments
explaining what goes on_ might be solution.
Best regards,
Pavel
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