Messages in this thread | | | Subject | Re: [PATCH v4 04/10] x86/xsaves: Introduce a new check that allows correct xstates copy from kernel to user directly | From | Dave Hansen <> | Date | Mon, 2 May 2016 14:32:14 -0700 |
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On 05/02/2016 02:24 PM, Yu-cheng Yu wrote: > On Mon, May 02, 2016 at 02:18:17PM -0700, Yu-cheng Yu wrote: >> > Before Linux gets into copy_fpstate_to_sigframe(), >> > current->thread.fpu.fpstate_active must be true. >> > For eagerfpu, fpregs_active() must also be true. >> > For lazyfpu, once we try to do FSAVE/FXSAVE/XSAVE, >> > fpregs_active() will become true as well. >> > >> > We should have not based on boot_cpu_has(X86_FEATURE_XSAVES) >> > at all. >> > >> > Why don't we make it simple and always copy_fpregs_to_signal_frame()? >> > Or, only for the lazy case, i.e. !fpregs_active(), we do __copy_to_user(). > For (lazy && not XSAVES) actually!
I think we're off in the weeds here.
Please just send an updated patch for what you want to do here.
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