Messages in this thread | | | Date | Mon, 9 May 2016 16:44:17 -0700 | From | Yu-cheng Yu <> | Subject | Re: [PATCH v5 11/13] x86/xsaves: Add WARN_ON_FPU() when a disabled xstate component offset is requested for a compacted format |
| |
On Mon, May 09, 2016 at 04:31:18PM -0700, Dave Hansen wrote: > On 05/09/2016 01:46 PM, Yu-cheng Yu wrote: > > Add a warning in case a disabled (not existing) xstate component offset > > is requested. > ... > > diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c > > index 350814c..2e6dbfe 100644 > > --- a/arch/x86/kernel/fpu/xstate.c > > +++ b/arch/x86/kernel/fpu/xstate.c > > @@ -756,6 +756,7 @@ void *__raw_xsave_addr(struct xregs_state *xsave, int xstate_feature_mask) > > { > > int feature_nr = fls64(xstate_feature_mask) - 1; > > > > + WARN_ON_FPU(using_compacted_format() && !xfeature_enabled(feature_nr)); > > return (void *)xsave + xstate_comp_offsets[feature_nr]; > > } > > Why the using_compacted_format()? Shouldn't this be an error, regardless.
If the kernel is not using compacted format, I can get a component offset, no?
> > Also, what is xstate_comp_offsets[feature_nr] in this case? Isn't it > -1? Should we be returning NULL along with WARN()ing?
NULL makes sense. I will change it.
| |