[PATCH V2 0/3] mm/debug: Add more arch page table helper tests

[Anshuman Khandual]

This series adds more arch page table helper tests. The new tests here are
either related to core memory functions and advanced arch pgtable helpers.
This also creates a documentation file enlisting all expected semantics as
suggested by Mike Rapoport (https://lkml.org/lkml/2020/1/30/40).

This series has been tested on arm64 and x86 platforms. There is just one
expected failure on arm64 that will be fixed when we enable THP migration.

[   21.741634] WARNING: CPU: 0 PID: 1 at mm/debug_vm_pgtable.c:782

which corresponds to

WARN_ON(!pmd_present(pmd_mknotpresent(pmd_mkhuge(pmd))))

There are many TRANSPARENT_HUGEPAGE and ARCH_HAS_TRANSPARENT_HUGEPAGE_PUD
ifdefs scattered across the test. But consolidating all the fallback stubs
is not very straight forward because ARCH_HAS_TRANSPARENT_HUGEPAGE_PUD is
not explicitly dependent on ARCH_HAS_TRANSPARENT_HUGEPAGE.

This series has been build tested on many platforms including the ones that
subscribe the test through ARCH_HAS_DEBUG_VM_PGTABLE.

This series is based on v5.6-rc7 after applying these following patches.

1. https://patchwork.kernel.org/patch/11431277/
2. https://patchwork.kernel.org/patch/11452185/

Changes in V2:

- Dropped CONFIG_ARCH_HAS_PTE_SPECIAL per Christophe
- Dropped CONFIG_NUMA_BALANCING per Christophe
- Dropped CONFIG_HAVE_ARCH_SOFT_DIRTY per Christophe
- Dropped CONFIG_MIGRATION per Christophe
- Replaced CONFIG_S390 with __HAVE_ARCH_PMDP_INVALIDATE
- Moved page allocation & free inside swap_migration_tests() per Christophe
- Added CONFIG_TRANSPARENT_HUGEPAGE to protect pfn_pmd()
- Added CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD to protect pfn_pud()
- Added a patch for other arch advanced page table helper tests
- Added a patch creating a documentation for page table helper semantics

Changes in V1: (https://patchwork.kernel.org/patch/11408253/)

Cc: Jonathan Corbet <corbet at lwn.net>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Mike Rapoport <rppt at linux.ibm.com>
Cc: Vineet Gupta <vgupta at synopsys.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Cc: Paul Mackerras <paulus at samba.org>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens at de.ibm.com>
Cc: Vasily Gorbik <gor at linux.ibm.com>
Cc: Christian Borntraeger <borntraeger at de.ibm.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Ingo Molnar <mingo at redhat.com>
Cc: Borislav Petkov <bp at alien8.de>
Cc: "H. Peter Anvin" <hpa at zytor.com>
Cc: Kirill A. Shutemov <kirill at shutemov.name>
Cc: Paul Walmsley <paul.walmsley at sifive.com>
Cc: Palmer Dabbelt <palmer at dabbelt.com>
Cc: linux-snps-arc at lists.infradead.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linuxppc-dev at lists.ozlabs.org
Cc: linux-s390 at vger.kernel.org
Cc: linux-riscv at lists.infradead.org
Cc: x86 at kernel.org
Cc: linux-doc at vger.kernel.org
Cc: linux-arch at vger.kernel.org
Cc: linux-kernel at vger.kernel.org

Anshuman Khandual (3):
  mm/debug: Add tests validating arch page table helpers for core features
  mm/debug: Add tests validating arch advanced page table helpers
  Documentation/mm: Add descriptions for arch page table helpers

 Documentation/vm/arch_pgtable_helpers.rst | 256 ++++++++++
 mm/debug_vm_pgtable.c                     | 594 +++++++++++++++++++++-
 2 files changed, 839 insertions(+), 11 deletions(-)
 create mode 100644 Documentation/vm/arch_pgtable_helpers.rst

-- 
2.20.1