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    SubjectRe: [RFC PATCH v2 25/27] x86/cet: Add PTRACE interface for CET
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    On Thu, 2018-07-12 at 16:03 +0200, Ingo Molnar wrote:
    > * Yu-cheng Yu <yu-cheng.yu@intel.com> wrote:
    >
    > >
    > > >
    > > > >
    > > > > diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
    > > > > index e2ee403865eb..ac2bc3a18427 100644
    > > > > --- a/arch/x86/kernel/ptrace.c
    > > > > +++ b/arch/x86/kernel/ptrace.c
    > > > > @@ -49,7 +49,9 @@ enum x86_regset {
    > > > >   REGSET_IOPERM64 = REGSET_XFP,
    > > > >   REGSET_XSTATE,
    > > > >   REGSET_TLS,
    > > > > + REGSET_CET64 = REGSET_TLS,
    > > > >   REGSET_IOPERM32,
    > > > > + REGSET_CET32,
    > > > >  };
    > > > Why does REGSET_CET64 alias on REGSET_TLS?
    > > In x86_64_regsets[], there is no [REGSET_TLS].  The core dump code
    > > cannot handle holes in the array.
    > Is there a fundamental (ABI) reason for that?

    What I did was, ran Linux with 'slub_debug', and forced a core dump
    (kill -abrt <pid>), then there was a red zone warning in the dmesg.
    My feeling is there could be issues in the core dump code.  These
    enum's are only local to arch/x86/kernel/ptrace.c and not exported.
    I am not aware this is in the ABI.

    >
    > >
    > > >
    > > > to "CET" (which is a well-known acronym for "Central European Time"),
    > > > not to CFE?
    > > >
    > > I don't know if I can change that, will find out.
    > So what I'd suggest is something pretty simple: to use CFT/cft in kernel internal 
    > names, except for the Intel feature bit and any MSR enumeration which can be CET 
    > if Intel named it that way, and a short comment explaining the acronym difference.
    >
    > Or something like that.

    Ok, I will make changes in the next version and probably revise
    from that if still not optimal.

    Yu-cheng

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