On 10/26/2017 06:52 AM, Brian Gerst wrote: > On Thu, Oct 26, 2017 at 4:26 AM, Andy Lutomirski <[email protected]> wrote: >> All of the code paths that ended up doing IRET to usermode did >> SWAPGS immediately beforehand. Move the SWAPGS into the common >> code. >> >> Signed-off-by: Andy Lutomirski <[email protected]> > >> +GLOBAL(swapgs_restore_regs_and_return_to_usermode) > > Is adding swapgs to the label really necessary? It's redundant with > the usermode part. I'm noticing a trend towards absurdly verbose > labels lately.
I kinda appreciate the verbosity. When I see a jump to such a label, I know explicitly what the jumper has to do. While it's possible that every "return to usermode" spot in the kernel does a swapgs, it's not patently obvious to me that every last one does that in every last situation. There are also places where we do register restoring after swapgs and then return to userspace. It's nice to know what mode we are in and what we are supposed to to just from the label.
