On 10/28/2019 10:59 AM, Anshuman Khandual wrote:
> This adds tests which will validate architecture page table helpers and
> other accessors in their compliance with expected generic MM semantics.
> This will help various architectures in validating changes to existing
> page table helpers or addition of new ones.
>
> This test covers basic page table entry transformations including but not
> limited to old, young, dirty, clean, write, write protect etc at various
> level along with populating intermediate entries with next page table page
> and validating them.
>
> Test page table pages are allocated from system memory with required size
> and alignments. The mapped pfns at page table levels are derived from a
> real pfn representing a valid kernel text symbol. This test gets called
> right after page_alloc_init_late().
>
> This gets build and run when CONFIG_DEBUG_VM_PGTABLE is selected along with
> CONFIG_VM_DEBUG. Architectures willing to subscribe this test also need to
> select CONFIG_ARCH_HAS_DEBUG_VM_PGTABLE which for now is limited to x86 and
> arm64. Going forward, other architectures too can enable this after fixing
> build or runtime problems (if any) with their page table helpers.
>
> Folks interested in making sure that a given platform's page table helpers
> conform to expected generic MM semantics should enable the above config
> which will just trigger this test during boot. Any non conformity here will
> be reported as an warning which would need to be fixed. This test will help
> catch any changes to the agreed upon semantics expected from generic MM and
> enable platforms to accommodate it thereafter.
>
> Cc: Andrew Morton <[email protected]>
> Cc: Vlastimil Babka <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Mike Rapoport <[email protected]>
> Cc: Jason Gunthorpe <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Michal Hocko <[email protected]>
> Cc: Mark Rutland <[email protected]>
> Cc: Mark Brown <[email protected]>
> Cc: Steven Price <[email protected]>
> Cc: Ard Biesheuvel <[email protected]>
> Cc: Masahiro Yamada <[email protected]>
> Cc: Kees Cook <[email protected]>
> Cc: Tetsuo Handa <[email protected]>
> Cc: Matthew Wilcox <[email protected]>
> Cc: Sri Krishna chowdary <[email protected]>
> Cc: Dave Hansen <[email protected]>
> Cc: Russell King - ARM Linux <[email protected]>
> Cc: Michael Ellerman <[email protected]>
> Cc: Paul Mackerras <[email protected]>
> Cc: Martin Schwidefsky <[email protected]>
> Cc: Heiko Carstens <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Vineet Gupta <[email protected]>
> Cc: James Hogan <[email protected]>
> Cc: Paul Burton <[email protected]>
> Cc: Ralf Baechle <[email protected]>
> Cc: Kirill A. Shutemov <[email protected]>
> Cc: Gerald Schaefer <[email protected]>
> Cc: Christophe Leroy <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
>
> Tested-by: Christophe Leroy <[email protected]> #PPC32
> Suggested-by: Catalin Marinas <[email protected]>
> Signed-off-by: Andrew Morton <[email protected]>
> Signed-off-by: Christophe Leroy <[email protected]>
> Signed-off-by: Anshuman Khandual <[email protected]>
> ---
>
> This adds a test validation for architecture exported page table helpers.
> Patch adds basic transformation tests at various levels of the page table.
>
> This test was originally suggested by Catalin during arm64 THP migration
> RFC discussion earlier. Going forward it can include more specific tests
> with respect to various generic MM functions like THP, HugeTLB etc and
> platform specific tests.
>
> https://lore.kernel.org/linux-mm/[email protected]/
>
> Needs to be applied on linux-next (next-20191025).
>
> Changes in V8:
>
> - Enabled ARCH_HAS_DEBUG_VM_PGTABLE on PPC32 platform per Christophe
> - Updated feature documentation as DEBUG_VM_PGTABLE is now enabled on PPC32
> platform
> - Moved ARCH_HAS_DEBUG_VM_PGTABLE earlier to indent it with DEBUG_VM per
> Christophe
> - Added an information message in debug_vm_pgtable() per Christophe
> - Dropped random_vaddr boundary condition checks per Christophe and Qian
> - Replaced virt_addr_valid() check with pfn_valid() check in
> debug_vm_pgtable()
Hello Andrew,
Just wondering if this version looks okay or is there anything else which still
needs to be accommodated here first, before this test can be considered for
merging ?
Thank you.
- Anshuman
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