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.
