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    SubjectRe: [PATCH v9 00/21] Generic page walk and ptdump
    On Mon, Jul 22, 2019 at 04:41:49PM +0100, Steven Price wrote:
    > This is a slight reworking and extension of my previous patch set
    > (Convert x86 & arm64 to use generic page walk), but I've continued the
    > version numbering as most of the changes are the same. In particular
    > this series ends with a generic PTDUMP implemention for arm64 and x86.
    >
    > Many architectures current have a debugfs file for dumping the kernel
    > page tables. Currently each architecture has to implement custom
    > functions for this because the details of walking the page tables used
    > by the kernel are different between architectures.
    >
    > This series extends the capabilities of walk_page_range() so that it can
    > deal with the page tables of the kernel (which have no VMAs and can
    > contain larger huge pages than exist for user space). A generic PTDUMP
    > implementation is the implemented making use of the new functionality of
    > walk_page_range() and finally arm64 and x86 are switch to using it,
    > removing the custom table walkers.
    >
    > To enable a generic page table walker to walk the unusual mappings of
    > the kernel we need to implement a set of functions which let us know
    > when the walker has reached the leaf entry. After a suggestion from Will
    > Deacon I've chosen the name p?d_leaf() as this (hopefully) describes
    > the purpose (and is a new name so has no historic baggage). Some
    > architectures have p?d_large macros but this is easily confused with
    > "large pages".
    >
    > Mostly this is a clean up and there should be very little functional
    > change. The exceptions are:
    >
    > * x86 PTDUMP debugfs output no longer display pages which aren't
    > present (patch 14).
    >
    > * arm64 has the ability to efficiently process KASAN pages (which
    > previously only x86 implemented). This means that the combination of
    > KASAN and DEBUG_WX is now useable.

    Are there any visible changes to the arm64 output?

    Could you dump a before/after example somewhere?

    Thanks,
    Mark.

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