Messages in this thread | | | Date | Mon, 23 Apr 2018 19:48:50 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH 28/37] x86/mm/pti: Map kernel-text to user-space on 32 bit kernels |
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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@8bytes.org> wrote: > > From: Joerg Roedel <jroedel@suse.de> > > > > 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@viggo.jf.intel.com
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
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