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SubjectRe: [patch 00/11] x86/vdso: Cleanups, simmplifications and CLOCK_TAI support
On Fri, 14 Sep 2018, Florian Weimer wrote:

> On 09/14/2018 02:50 PM, Thomas Gleixner wrote:
> > Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime()
> > implementation, which extended the clockid switch case and added yet
> > another slightly different copy of the same code.
> >
> > Especially the extended switch case is problematic as the compiler tends to
> > generate a jump table which then requires to use retpolines.
>
> Does vDSO code really have to use retpolines? It's in userspace, after all.

Unless you have IBRS/STIPB enabled, you need user space ratpoutine as well.

Thanks,

tglx

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