Messages in this thread | | | Date | Sun, 14 Jan 2018 16:28:47 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [tip:x86/pti] x86/retpoline: Fill return stack buffer on vmexit |
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On Sun, 14 Jan 2018, Borislav Petkov wrote:
> On Fri, Jan 12, 2018 at 03:37:49AM -0800, tip-bot for David Woodhouse wrote: > > Commit-ID: 117cc7a908c83697b0b737d15ae1eb5943afe35b > > Gitweb: https://git.kernel.org/tip/117cc7a908c83697b0b737d15ae1eb5943afe35b > > Author: David Woodhouse <dwmw@amazon.co.uk> > > AuthorDate: Fri, 12 Jan 2018 11:11:27 +0000 > > Committer: Thomas Gleixner <tglx@linutronix.de> > > CommitDate: Fri, 12 Jan 2018 12:33:37 +0100 > > > > x86/retpoline: Fill return stack buffer on vmexit > > ... > > > + /* > > + * A simpler FILL_RETURN_BUFFER macro. Don't make people use the CPP > > + * monstrosity above, manually. > > + */ > > +.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req > > +#ifdef CONFIG_RETPOLINE > > + ANNOTATE_NOSPEC_ALTERNATIVE > > + ALTERNATIVE "jmp .Lskip_rsb_\@", \ > > + __stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)) \ > > + \ftr > > +.Lskip_rsb_\@: > > +#endif > > +.endm > > Looks unused to me. Was it ever gound to be used? If not:
It's for the outstanding RSB fill after context switch.
Thanks,
tglx
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