Messages in this thread | | | Date | Mon, 1 Apr 2019 10:24:24 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH 18/24] x86/fpu: Prepare copy_fpstate_to_sigframe() for TIF_NEED_FPU_LOAD |
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On 2019-03-31 20:20:25 [+0200], Thomas Gleixner wrote: > > I think this should do the following: > > fpregs_lock(); > if (!test_thread_flag(TIF_NEED_FPU_LOAD)) { > pagefault_disable(); > ret = copy_fpu_to_user(...); > pagefault_enable(); > if (!res) > return 0; > copy_fpregs_to_fpstate(fpu); > } > fpregs_unlock(); > > The point is that in most cases the direct store from the FPU registers to > user space will succeed simply because the stack is accessible and you only > do the store in kernel memory and copy when that fails.
let me try that.
> Thanks, > > tglx >
Sebastian
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