Building on the work of Christophe, Aneesh and Balbir, I've ported KASAN to 64-bit Book3S kernels running on the Radix MMU. v10 rebases on top of next-20210125, fixing things up to work on top of the latest changes, and fixing some review comments from Christophe. I have tested host and guest with 64k pages for this spin. It does not apply to powerpc/next, sorry: there are conflicting kasan changes staged in next. There is now only 1 failing KUnit test: kasan_global_oob - gcc puts the ASAN init code in a section called '.init_array'. Powerpc64 module loading code goes through and _renames_ any section beginning with '.init' to begin with '_init' in order to avoid some complexities around our 24-bit indirect jumps. This means it renames '.init_array' to '_init_array', and the generic module loading code then fails to recognise the section as a constructor and thus doesn't run it. This hack dates back to 2003 and so I'm not going to try to unpick it in this series. (I suspect this may have previously worked if the code ended up in .ctors rather than .init_array but I don't keep my old binaries around so I have no real way of checking.) (The previously failing stack tests are now skipped due to more accurate configuration settings.) Details from v9: This is a significant reworking of the previous versions. Instead of the previous approach which supported inline instrumentation, this series provides only outline instrumentation. To get around the problem of accessing the shadow region inside code we run with translations off (in 'real mode'), we we restrict checking to when translations are enabled. This is done via a new hook in the kasan core and by excluding larger quantites of arch code from instrumentation. The upside is that we no longer require that you be able to specify the amount of physically contiguous memory on the system at compile time. Hopefully this is a better trade-off. More details in patch 6. kexec works. Both 64k and 4k pages work. Running as a KVM host works, but nothing in arch/powerpc/kvm is instrumented. It's also potentially a bit fragile - if any real mode code paths call out to instrumented code, things will go boom. Kind regards, Daniel
