This version is two patches lighter than v16: mm: pagewalk: Add test_p?d callbacks x86: mm: Convert ptdump_walk_pgd_level_core() to take an mm_struct There is a new enum page_walk_action in struct mm_walk which allows the callbacks to decide whether to recurse (ACTION_SUBTREE - the default), skip (ACTION_CONTINUE) or to be called again (ACTION_AGAIN). These are introduced in patch 11 and used for hmm.c to adapt it to the new behaviour of the pud_entry() callback. The new page_walk_action means that we no longer need to test_p?d() callbacks as the p?d_entry() callbacks can simply return ACTION_CONTINUE to skip parts of the tree. The x86 patch is dropped because I've updated patch 20 to always use a 'fake_mm' structure which simplifies the code and avoids issues with potentially double locking the mmap_sem of the real mm. Previous description for the series ----------------------------------- 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". This series ends with a generic PTDUMP implemention for arm64 and x86. Mostly this is a clean up and there should be very little functional change. The exceptions are: * arm64 PTDUMP debugfs now displays pages which aren't present (patch 22). * 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. Also available as a git tree: git://linux-arm.org/linux-sp.git walk_page_range/v17 Changes since v16: https://lore.kernel.org/lkml/20191206135316.47703-1-steven.price@xxxxxxx/ * Introduced the ACTION_{SUBTREE,CONTINUE,AGAIN} concept suggested by Thomas Hellström * Reworked the KASAN support to avoid the need for test_p?d() callbacks by using ACTION_CONTINUE instead * powerpc: Use p?d_is_leaf rather than adding new functions * Simplify x86 changes by leaving ptdump_walk_pgd_level_core() taking a pgd Changes since v15: https://lore.kernel.org/lkml/20191101140942.51554-1-steven.price@xxxxxxx/ * Rebased onto Linus' tree, which includes the conflicting commit: ace88f1018b8 ("mm: pagewalk: Take the pagetable lock in walk_pte_range()") * New patch fixing conflict with above patch * Squashed in fix for ordering of "static const" * Squashed in fix checking p*d_present() * New patch fixing termination condition for walk_pte_range() Changes since v14: https://lore.kernel.org/lkml/20191028135910.33253-1-steven.price@xxxxxxx/ * Switch walk_page_range() into two functions, the existing walk_page_range() now still requires VMAs (and treats areas without a VMA as a 'hole'). The new walk_page_range_novma() ignores VMAs and will report the actual page table layout. This fixes the previous breakage of /proc/<pid>/pagemap * New patch at the end of the series which reduces the 'level' numbers by 1 to simplify the code slightly * Added tags Changes since v13: https://lore.kernel.org/lkml/20191024093716.49420-1-steven.price@xxxxxxx/ * Fixed typo in arc definition of pmd_leaf() spotted by the kbuild test robot * Added tags Changes since v12: https://lore.kernel.org/lkml/20191018101248.33727-1-steven.price@xxxxxxx/ * Correct code format in riscv pud_leaf()/pmd_leaf() * v12 may not have reached everyone because of mail server problems (which are now hopefully resolved!) Changes since v11: https://lore.kernel.org/lkml/20191007153822.16518-1-steven.price@xxxxxxx/ * Use "-1" as dummy depth parameter in patch 14. Changes since v10: https://lore.kernel.org/lkml/20190731154603.41797-1-steven.price@xxxxxxx/ * Rebased to v5.4-rc1 - mainly various updates to deal with the splitting out of ops from struct mm_walk. * Deal with PGD_LEVEL_MULT not always being constant on x86. Changes since v9: https://lore.kernel.org/lkml/20190722154210.42799-1-steven.price@xxxxxxx/ * Moved generic macros to first page in the series and explained the macro naming in the commit message. * mips: Moved macros to pgtable.h as they are now valid for both 32 and 64 bit * x86: Dropped patch which changed the debugfs output for x86, instead we have... * new patch adding 'depth' parameter to pte_hole. This is used to provide the necessary information to output lines for 'holes' in the debugfs files * new patch changing arm64 debugfs output to include holes to match x86 * generic ptdump KASAN handling has been simplified and now works with CONFIG_DEBUG_VIRTUAL. Changes since v8: https://lore.kernel.org/lkml/20190403141627.11664-1-steven.price@xxxxxxx/ * Rename from p?d_large() to p?d_leaf() * Dropped patches migrating arm64/x86 custom walkers to walk_page_range() in favour of adding a generic PTDUMP implementation and migrating arm64/x86 to that instead. * Rebased to v5.3-rc1 Steven Price (23): mm: Add generic p?d_leaf() macros arc: mm: Add p?d_leaf() definitions arm: mm: Add p?d_leaf() definitions arm64: mm: Add p?d_leaf() definitions mips: mm: Add p?d_leaf() definitions powerpc: mm: Add p?d_leaf() definitions riscv: mm: Add p?d_leaf() definitions s390: mm: Add p?d_leaf() definitions sparc: mm: Add p?d_leaf() definitions x86: mm: Add p?d_leaf() definitions mm: pagewalk: Add p4d_entry() and pgd_entry() mm: pagewalk: Allow walking without vma mm: pagewalk: Don't lock PTEs for walk_page_range_novma() mm: pagewalk: fix termination condition in walk_pte_range() mm: pagewalk: Add 'depth' parameter to pte_hole x86: mm: Point to struct seq_file from struct pg_state x86: mm+efi: Convert ptdump_walk_pgd_level() to take a mm_struct x86: mm: Convert ptdump_walk_pgd_level_debugfs() to take an mm_struct mm: Add generic ptdump x86: mm: Convert dump_pagetables to use walk_page_range arm64: mm: Convert mm/dump.c to use walk_page_range() arm64: mm: Display non-present entries in ptdump mm: ptdump: Reduce level numbers by 1 in note_page() arch/arc/include/asm/pgtable.h | 1 + arch/arm/include/asm/pgtable-2level.h | 1 + arch/arm/include/asm/pgtable-3level.h | 1 + arch/arm64/Kconfig | 1 + arch/arm64/Kconfig.debug | 19 +- arch/arm64/include/asm/pgtable.h | 2 + arch/arm64/include/asm/ptdump.h | 8 +- arch/arm64/mm/Makefile | 4 +- arch/arm64/mm/dump.c | 148 ++++----- arch/arm64/mm/mmu.c | 4 +- arch/arm64/mm/ptdump_debugfs.c | 2 +- arch/mips/include/asm/pgtable.h | 5 + arch/powerpc/include/asm/book3s/64/pgtable.h | 3 + arch/riscv/include/asm/pgtable-64.h | 7 + arch/riscv/include/asm/pgtable.h | 7 + arch/s390/include/asm/pgtable.h | 2 + arch/sparc/include/asm/pgtable_64.h | 2 + arch/x86/Kconfig | 1 + arch/x86/Kconfig.debug | 20 +- arch/x86/include/asm/pgtable.h | 10 +- arch/x86/mm/Makefile | 4 +- arch/x86/mm/debug_pagetables.c | 8 +- arch/x86/mm/dump_pagetables.c | 320 +++++-------------- arch/x86/platform/efi/efi_32.c | 2 +- arch/x86/platform/efi/efi_64.c | 4 +- drivers/firmware/efi/arm-runtime.c | 2 +- fs/proc/task_mmu.c | 4 +- include/asm-generic/pgtable.h | 20 ++ include/linux/pagewalk.h | 46 ++- include/linux/ptdump.h | 22 ++ mm/Kconfig.debug | 21 ++ mm/Makefile | 1 + mm/hmm.c | 59 ++-- mm/migrate.c | 5 +- mm/mincore.c | 1 + mm/pagewalk.c | 156 ++++++--- mm/ptdump.c | 139 ++++++++ 37 files changed, 596 insertions(+), 466 deletions(-) create mode 100644 include/linux/ptdump.h create mode 100644 mm/ptdump.c -- 2.20.1
