Re: [patch 2/9] x86/process: Unify copy_thread_tls()

Thomas Gleixner
2019-11-10T12:36:16Z

On Sat, 9 Nov 2019, Thomas Gleixner wrote:
> On Fri, 8 Nov 2019, Andy Lutomirski wrote:
> > On 11/6/19 11:35 AM, Thomas Gleixner wrote:
> > > +static inline int copy_io_bitmap(struct task_struct *tsk)
> > > +{
> > > + if (likely(!test_tsk_thread_flag(current, TIF_IO_BITMAP)))
> > > + return 0;
> > > +
> > > + tsk->thread.io_bitmap_ptr = kmemdup(current->thread.io_bitmap_ptr,
> > > + IO_BITMAP_BYTES, GFP_KERNEL);
> >
> > tsk->thread.io_bitmap_max = current->thread.io_bitmap_max?
> >
> > I realize you inherited this from the code you're refactoring, but it
> > does seem to be missing.
>
> It already got copied with the task struct :)
>
> > > +#ifdef CONFIG_X86_64
> > > + savesegment(gs, p->thread.gsindex);
> > > + p->thread.gsbase = p->thread.gsindex ? 0 : current->thread.gsbase;
> > > + savesegment(fs, p->thread.fsindex);
> > > + p->thread.fsbase = p->thread.fsindex ? 0 : current->thread.fsbase;
> > > + savesegment(es, p->thread.es);
> > > + savesegment(ds, p->thread.ds);
> > > +#else
> > > + /* Clear all status flags including IF and set fixed bit. */
> > > + frame->flags = X86_EFLAGS_FIXED;
> > > +#endif
> >
> > Want to do another commit to make the eflags fixup unconditional? I'm
> > wondering if we have a bug.
>
> Let me look at that.

64bit does not have flags in the inactive_task_frame ...

Thanks,

tglx