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    SubjectRe: [v3 03/12] x86/fsgsbase/64: Add intrinsics/macros for FSGSBASE instructions
    On Tue, Oct 23, 2018 at 11:43 AM Chang S. Bae <chang.seok.bae@intel.com> wrote:
    >
    > From: Andi Kleen <ak@linux.intel.com>
    >
    > Add C intrinsics and assembler macros for the new FSBASE and GSBASE
    > instructions.
    >
    > Very straight forward. Used in followon patches.
    >
    > [ luto: Rename the variables from FS and GS to FSBASE and GSBASE and
    > make <asm/fsgsbase.h> safe to include on 32-bit kernels. ]
    >
    > v2: Use __always_inline
    >
    > [ chang: Revise the changelog. Place them in <asm/fsgsbase.h>. Replace
    > the macros with GAS-compatible ones. ]
    >
    > If GCC supports it, we can add -mfsgsbase to CFLAGS and use the builtins
    > here for extra performance.

    Reviewed-by: Andy Lutomirski <luto@kernel.org> # C parts only

    With the caveat that I'm not convinced that the memory clobbers are
    needed. The __force_order trick in special_insns.h would probably be
    more appropriate.

    I don't feel qualified to review the asm part without some research.
    Whereas hpa or Boris could probably review it with their eyes closed.

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