Messages in this thread | | | Date | Mon, 2 May 2016 09:34:10 -0700 | From | Yu-cheng Yu <> | Subject | Re: [PATCH v4 04/10] x86/xsaves: Introduce a new check that allows correct xstates copy from kernel to user directly |
| |
On Mon, May 02, 2016 at 09:06:41AM -0700, Dave Hansen wrote: > On 05/02/2016 08:57 AM, Yu-cheng Yu wrote: > > On Fri, Apr 29, 2016 at 05:36:48PM -0700, Dave Hansen wrote: > >> If may_copy_fpregs_to_sigframe() were called from a slightly different > >> context, or if we change the call-site, what breaks? > >> > >> In other words. if we can still "may_copy_fpregs_to_sigframe()" no > >> matter the state of fpu.fpstate_active, then I don't think we should be > >> checking it in may_copy_fpregs_to_sigframe(). > > > > Do you mean, don't check fpu.fpstate_active here? > > Not really. I'm asking *why* the check is there.
If (fpu.fpstate_active == 0), then the task does not use FPU; we don't want to save these registers, right?
| |