| Date | Thu, 18 Jan 2018 11:44:53 -0800 | From | Tim Chen <> | Subject | Re: [PATCH 26/35] x86/enter: Create macros to stop/restart Indirect Branch Speculation |
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On Thu, Jan 18, 2018 at 02:48:26PM +0100, Peter Zijlstra wrote: > From: Tim Chen <tim.c.chen@linux.intel.com> > > + > +.macro STOP_IB_SPEC > + ALTERNATIVE "jmp .Lskip_\@", "", X86_FEATURE_IBRS
Peter,
Will it be possible to use static key here like STATIC_JUMP_IF_FALSE .Lskip_\@, specctrl_ibrs, def=0
In Thomas' original patchset, there is a specctrl_ibrs static key.
That will make a switch of static branch here easier if we want to change it later in boot or at run time.
Tim
> + PUSH_MSR_REGS > + WRMSR_ASM $MSR_IA32_SPEC_CTRL, $0, $SPEC_CTRL_ENABLE_IBRS > + POP_MSR_REGS > +.Lskip_\@: > +.endm > +
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