| Subject | Re: [PATCH 00/23] KAISER: unmap most of the kernel from userspace page tables | From | Dave Hansen <> | Date | Thu, 2 Nov 2017 12:38:05 -0700 |
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On 11/02/2017 12:01 PM, Will Deacon wrote: > On Tue, Oct 31, 2017 at 03:31:46PM -0700, Dave Hansen wrote: >> KAISER makes it harder to defeat KASLR, but makes syscalls and >> interrupts slower. These patches are based on work from a team at >> Graz University of Technology posted here[1]. The major addition is >> support for Intel PCIDs which builds on top of Andy Lutomorski's PCID >> work merged for 4.14. PCIDs make KAISER's overhead very reasonable >> for a wide variety of use cases. > I just wanted to say that I've got a version of this up and running for > arm64. I'm still ironing out a few small details, but I hope to post it > after the merge window. We always use ASIDs, and the perf impact looks > like it aligns roughly with your findings for a PCID-enabled x86 system.
Welcome to the party!
I don't know if you've found anything different, but there been woefully little code that's really cross-architecture. The kernel task stack-mapping stuff _was_, but it's going away. The per-cpu-user-mapped section stuff might be common, I guess.
Is there any other common infrastructure that we can or should be sharing?
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