On Mon, Apr 23, 2018 at 10:09:19AM -0700, Kees Cook wrote: > On Mon, Apr 23, 2018 at 8:47 AM, Joerg Roedel <joro@xxxxxxxxxx> wrote: > > From: Joerg Roedel <jroedel@xxxxxxx> > > > > Keeping the kernel text mapped with G bit set keeps its > > entries in the TLB across kernel entry/exit and improved the > > performance. The 64 bit x86 kernels already do this when > > there is no PCID, so do this in 32 bit as well since PCID is > > not even supported there. > > I think this should keep at least part of the logic as 64-bit since > there are other reasons to turn off the Global flag: > > https://lkml.kernel.org/r/20180420222026.D0B4AAC9@xxxxxxxxxxxxxxxxxx That patch you linked is for function pti_kernel_image_global_ok() which is used on 32 bit too. So any logic implemented for 64 bit to turn off the global bit will automatically be used on 32 bit. Regards, Joerg
