On Fri, Jun 22, 2018 at 7:28 AM Thomas Gleixner <[email protected]> wrote: > > On Wed, 20 Jun 2018, Chang S. Bae wrote: > > +void write_fsbase(unsigned long fsbase) > > +{ > > + /* set the selector to 0 to not confuse __switch_to */ > > 'to not confuse __switch_to' is not that helpful of a comment as it > requires to stare into __switch_to to figure out what might get confused > there. Please write it out why this needs to be done in technical terms. > > > + loadseg(FS, 0); > > + wrmsrl(MSR_FS_BASE, fsbase); > > +} > > + > > +void write_inactive_gsbase(unsigned long gsbase) > > +{ > > + /* set the selector to 0 to not confuse __switch_to */ > > Ditto > > > + loadseg(GS, 0); > > + wrmsrl(MSR_KERNEL_GS_BASE, gsbase); > > +} > > + > > +unsigned long read_task_fsbase(struct task_struct *task) > > +{ > > + unsigned long fsbase; > > + > > + if (task == current) { > > + fsbase = read_fsbase(); > > + } else { > > + /* > > + * XXX: This will not behave as expected if called > > + * if fsindex != 0. This preserves an existing bug > > + * that will be fixed. > > I'm late to this party, but let me ask the obvious question: > > Why is the existing bug not fixed as the first patch in the series?
IIRC that was how I did it in the old version of this code. I think it did it because it was less messy to fix the bug after cleaning up the code, but I could be remembering wrong.
