[V11,RESEND] mm/debug: Add tests validating architecture page table helpers

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 <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Steven Price <Steven.Price@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sri Krishna chowdary <schowdary@nvidia.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-mips@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-ia64@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org

Tested-by: Christophe Leroy <christophe.leroy@c-s.fr>		#PPC32
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
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/20190628102003.GA56463@arrakis.emea.arm.com/

Needs to be applied on linux 5.5-rc2

Changes in V11:

- Rebased the patch on 5.5-rc2

Changes in V10: (https://patchwork.kernel.org/project/linux-mm/list/?series=205529)

- Always enable DEBUG_VM_PGTABLE when DEBUG_VM is enabled per Ingo
- Added tags from Ingo

Changes in V9: (https://patchwork.kernel.org/project/linux-mm/list/?series=201429)

- Changed feature support enumeration for powerpc platforms per Christophe
- Changed config wrapper for basic_[pmd|pud]_tests() to enable ARC platform
- Enabled the test on ARC platform

Changes in V8: (https://patchwork.kernel.org/project/linux-mm/list/?series=194297)

- 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()
- Slightly changed pr_fmt(fmt) information

Changes in V7: (https://patchwork.kernel.org/project/linux-mm/list/?series=193051)

- Memory allocation and free routines for mapped pages have been droped
- Mapped pfns are derived from standard kernel text symbol per Matthew
- Moved debug_vm_pgtaable() after page_alloc_init_late() per Michal and Qian 
- Updated the commit message per Michal
- Updated W=1 GCC warning problem on x86 per Qian Cai
- Addition of new alloc_contig_pages() helper has been submitted separately

Changes in V6: (https://patchwork.kernel.org/project/linux-mm/list/?series=187589)

- Moved alloc_gigantic_page_order() into mm/page_alloc.c per Michal
- Moved alloc_gigantic_page_order() within CONFIG_CONTIG_ALLOC in the test
- Folded Andrew's include/asm-generic/pgtable.h fix into the test patch 2/2

Changes in V5: (https://patchwork.kernel.org/project/linux-mm/list/?series=185991)

- Redefined and moved X86 mm_p4d_folded() into a different header per Kirill/Ingo
- Updated the config option comment per Ingo and dropped 'kernel module' reference
- Updated the commit message and dropped 'kernel module' reference
- Changed DEBUG_ARCH_PGTABLE_TEST into DEBUG_VM_PGTABLE per Ingo
- Moved config option from mm/Kconfig.debug into lib/Kconfig.debug
- Renamed core test function arch_pgtable_tests() as debug_vm_pgtable()
- Renamed mm/arch_pgtable_test.c as mm/debug_vm_pgtable.c
- debug_vm_pgtable() gets called from kernel_init_freeable() after init_mm_internals()
- Added an entry in Documentation/features/debug/ per Ingo
- Enabled the test on arm64 and x86 platforms for now

Changes in V4: (https://patchwork.kernel.org/project/linux-mm/list/?series=183465)

- Disable DEBUG_ARCH_PGTABLE_TEST for ARM and IA64 platforms

Changes in V3: (https://lore.kernel.org/patchwork/project/lkml/list/?series=411216)

- Changed test trigger from module format into late_initcall()
- Marked all functions with __init to be freed after completion
- Changed all __PGTABLE_PXX_FOLDED checks as mm_pxx_folded()
- Folded in PPC32 fixes from Christophe

Changes in V2:

https://lore.kernel.org/linux-mm/1568268173-31302-1-git-send-email-anshuman.khandual@arm.com/T/#t

- Fixed small typo error in MODULE_DESCRIPTION()
- Fixed m64k build problems for lvalue concerns in pmd_xxx_tests()
- Fixed dynamic page table level folding problems on x86 as per Kirril
- Fixed second pointers during pxx_populate_tests() per Kirill and Gerald
- Allocate and free pte table with pte_alloc_one/pte_free per Kirill
- Modified pxx_clear_tests() to accommodate s390 lower 12 bits situation
- Changed RANDOM_NZVALUE value from 0xbe to 0xff
- Changed allocation, usage, free sequence for saved_ptep
- Renamed VMA_FLAGS as VMFLAGS
- Implemented a new method for random vaddr generation
- Implemented some other cleanups
- Dropped extern reference to mm_alloc()
- Created and exported new alloc_gigantic_page_order()
- Dropped the custom allocator and used new alloc_gigantic_page_order()

Changes in V1:

https://lore.kernel.org/linux-mm/1567497706-8649-1-git-send-email-anshuman.khandual@arm.com/

- Added fallback mechanism for PMD aligned memory allocation failure

Changes in RFC V2:

https://lore.kernel.org/linux-mm/1565335998-22553-1-git-send-email-anshuman.khandual@arm.com/T/#u

- Moved test module and it's config from lib/ to mm/
- Renamed config TEST_ARCH_PGTABLE as DEBUG_ARCH_PGTABLE_TEST
- Renamed file from test_arch_pgtable.c to arch_pgtable_test.c
- Added relevant MODULE_DESCRIPTION() and MODULE_AUTHOR() details
- Dropped loadable module config option
- Basic tests now use memory blocks with required size and alignment
- PUD aligned memory block gets allocated with alloc_contig_range()
- If PUD aligned memory could not be allocated it falls back on PMD aligned
  memory block from page allocator and pud_* tests are skipped
- Clear and populate tests now operate on real in memory page table entries
- Dummy mm_struct gets allocated with mm_alloc()
- Dummy page table entries get allocated with [pud|pmd|pte]_alloc_[map]()
- Simplified [p4d|pgd]_basic_tests(), now has random values in the entries

Original RFC V1:

https://lore.kernel.org/linux-mm/1564037723-26676-1-git-send-email-anshuman.khandual@arm.com/

 .../debug/debug-vm-pgtable/arch-support.txt   |  35 ++
 arch/arc/Kconfig                              |   1 +
 arch/arm64/Kconfig                            |   1 +
 arch/powerpc/Kconfig                          |   1 +
 arch/x86/Kconfig                              |   1 +
 arch/x86/include/asm/pgtable_64.h             |   6 +
 include/asm-generic/pgtable.h                 |   6 +
 init/main.c                                   |   1 +
 lib/Kconfig.debug                             |  22 +
 mm/Makefile                                   |   1 +
 mm/debug_vm_pgtable.c                         | 388 ++++++++++++++++++
 11 files changed, 463 insertions(+)
 create mode 100644 Documentation/features/debug/debug-vm-pgtable/arch-support.txt
 create mode 100644 mm/debug_vm_pgtable.c

Message ID	1577162322-30303-1-git-send-email-anshuman.khandual@arm.com
State	New
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Shutemov" <kirill@shutemov.name>, Dan Williams <dan.j.williams@intel.com>, Vlastimil Babka <vbabka@suse.cz>, Christophe Leroy <christophe.leroy@c-s.fr>, Sri Krishna chowdary <schowdary@nvidia.com>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, linux-mips@vger.kernel.org, Ralf Baechle <ralf@linux-mips.org>, linux-kernel@vger.kernel.org, Paul Burton <paul.burton@mips.com>, Mike Rapoport <rppt@linux.vnet.ibm.com>, Vineet Gupta <vgupta@synopsys.com>, Martin Schwidefsky <schwidefsky@de.ibm.com>, Andrew Morton <akpm@linux-foundation.org>, linuxppc-dev@lists.ozlabs.org, "David S. Miller" <davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-snps-arc" <linux-snps-arc-bounces@lists.infradead.org> Errors-To: linux-snps-arc-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org
Series	[V11,RESEND] mm/debug: Add tests validating architecture page table helpers \| expand [V11,RESEND] mm/debug: Add tests validating architecture page table helpers

[V11,RESEND] mm/debug: Add tests validating architecture page table helpers

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