Linus Torvalds writes: (Summary) wrote:
All the kernel entry code that is both in the user mapping and the kernel mapping should be marked G.
kernel mapping should be marked G.
We had missed a lot of it (and the impact is very small with PCID), but if you rebased on top of 4.17-rc1 you should have it fixed at least on 64-bit.
least on 64-bit.
See for example commit 8c06c7740d19 ("x86/pti: Leave kernel text global for !PCID") and in particular the performance numbers (that's an Atom microserver, but it was chosen due to lack of PCID).
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check what that is.All the kernel entry code that is both in the user mapping and the kernel mapping should be marked G.
kernel mapping should be marked G.
We had missed a lot of it (and the impact is very small with PCID), but if you rebased on top of 4.17-rc1 you should have it fixed at least on 64-bit.
least on 64-bit.
See for example commit 8c06c7740d19 ("x86/pti: Leave kernel text global for !PCID") and in particular the performance numbers (that's an Atom microserver, but it was chosen due to lack of PCID).