linux-toradex.git/mm/debug_vm_pgtable.c, branch v5.12-rc8

mm/debug_vm_pgtable/basic: iterate over entire protection_map[]

2021-02-24T21:38:27+00:00

Currently the basic tests just validate various page table transformations
after starting with vm_get_page_prot(VM_READ|VM_WRITE|VM_EXEC) protection.
Instead scan over the entire protection_map[] for better coverage.  It
also makes sure that all these basic page table tranformations checks hold
true irrespective of the starting protection value for the page table
entry.  There is also a slight change in the debug print format for basic
tests to capture the protection value it is being tested with.  The
modified output looks something like

[pte_basic_tests          ]: Validating PTE basic ()
[pte_basic_tests          ]: Validating PTE basic (read)
[pte_basic_tests          ]: Validating PTE basic (write)
[pte_basic_tests          ]: Validating PTE basic (read|write)
[pte_basic_tests          ]: Validating PTE basic (exec)
[pte_basic_tests          ]: Validating PTE basic (read|exec)
[pte_basic_tests          ]: Validating PTE basic (write|exec)
[pte_basic_tests          ]: Validating PTE basic (read|write|exec)
[pte_basic_tests          ]: Validating PTE basic (shared)
[pte_basic_tests          ]: Validating PTE basic (read|shared)
[pte_basic_tests          ]: Validating PTE basic (write|shared)
[pte_basic_tests          ]: Validating PTE basic (read|write|shared)
[pte_basic_tests          ]: Validating PTE basic (exec|shared)
[pte_basic_tests          ]: Validating PTE basic (read|exec|shared)
[pte_basic_tests          ]: Validating PTE basic (write|exec|shared)
[pte_basic_tests          ]: Validating PTE basic (read|write|exec|shared)

This adds a missing argument 'struct mm_struct *' in pud_basic_tests()
test .  This never got exposed before as PUD based THP is available only
on X86 platform where mm_pmd_folded(mm) call gets macro replaced without
requiring the mm_struct i.e __is_defined(__PAGETABLE_PMD_FOLDED).

Link: https://lkml.kernel.org/r/1611137241-26220-3-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual 
Tested-by: Gerald Schaefer  [s390]
Reviewed-by: Steven Price 
Suggested-by: Catalin Marinas 
Cc: Christophe Leroy 
Cc: Gerald Schaefer 
Cc: Paul Walmsley 
Cc: Vineet Gupta 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable/basic: add validation for dirtiness after write protect

2021-02-24T21:38:27+00:00

Patch series "mm/debug_vm_pgtable: Some minor updates", v3.

This series contains some cleanups and new test suggestions from Catalin
from an earlier discussion.

https://lore.kernel.org/linux-mm/20201123142237.GF17833@gaia/

This patch (of 2):

This adds validation tests for dirtiness after write protect conversion
for each page table level.  There are two new separate test types involved
here.

The first test ensures that a given page table entry does not become dirty
after pxx_wrprotect().  This is important for platforms like arm64 which
transfers and drops the hardware dirty bit (!PTE_RDONLY) to the software
dirty bit while making it an write protected one.  This test ensures that
no fresh page table entry could be created with hardware dirty bit set.
The second test ensures that a given page table entry always preserve the
dirty information across pxx_wrprotect().

This adds two previously missing PUD level basic tests and while here
fixes pxx_wrprotect() related typos in the documentation file.

Link: https://lkml.kernel.org/r/1611137241-26220-1-git-send-email-anshuman.khandual@arm.com
Link: https://lkml.kernel.org/r/1611137241-26220-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual 
Suggested-by: Catalin Marinas 
Tested-by: Gerald Schaefer  [s390]
Cc: Christophe Leroy 
Cc: Gerald Schaefer 
Cc: Vineet Gupta 
Cc: Paul Walmsley 
Cc: Steven Price 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable: avoid doing memory allocation with pgtable_t mapped.

2020-10-16T18:11:14+00:00

With highmem, pte_alloc_map() keep the level4 page table mapped using
kmap_atomic().  Avoid doing new memory allocation with page table mapped
like above.

[    9.409233] BUG: sleeping function called from invalid context at mm/page_alloc.c:4822
[    9.410557] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper
[    9.411932] no locks held by swapper/1.
[    9.412595] CPU: 0 PID: 1 Comm: swapper Not tainted 5.9.0-rc3-00323-gc50eb1ed654b5 #2
[    9.413824] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[    9.415207] Call Trace:
[    9.415651]  ? ___might_sleep.cold+0xa7/0xcc
[    9.416367]  ? __alloc_pages_nodemask+0x14c/0x5b0
[    9.417055]  ? swap_migration_tests+0x50/0x293
[    9.417704]  ? debug_vm_pgtable+0x4bc/0x708
[    9.418287]  ? swap_migration_tests+0x293/0x293
[    9.418911]  ? do_one_initcall+0x82/0x3cb
[    9.419465]  ? parse_args+0x1bd/0x280
[    9.419983]  ? rcu_read_lock_sched_held+0x36/0x60
[    9.420673]  ? trace_initcall_level+0x1f/0xf3
[    9.421279]  ? trace_initcall_level+0xbd/0xf3
[    9.421881]  ? do_basic_setup+0x9d/0xdd
[    9.422410]  ? do_basic_setup+0xc3/0xdd
[    9.422938]  ? kernel_init_freeable+0x72/0xa3
[    9.423539]  ? rest_init+0x134/0x134
[    9.424055]  ? kernel_init+0x5/0x12c
[    9.424574]  ? ret_from_fork+0x19/0x30

Reported-by: kernel test robot 
Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Andrew Morton 
Link: https://lkml.kernel.org/r/20200913110327.645310-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable: avoid none pte in pte_clear_test

2020-10-16T18:11:14+00:00

pte_clear_tests operate on an existing pte entry.  Make sure that is not a
none pte entry.

[aneesh.kumar@linux.ibm.com: avoid kernel crash with riscv]
  Link: https://lkml.kernel.org/r/20201015033206.140550-1-aneesh.kumar@linux.ibm.com

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Andrew Morton 
Reviewed-by: Anshuman Khandual 
Cc: Christophe Leroy 
Cc: Michael Ellerman 
Cc: Nathan Chancellor 
Cc: Guenter Roeck 
Cc: Paul Walmsley 
Cc: Albert Ou 
Cc: Palmer Dabbelt 
Link: https://lkml.kernel.org/r/20200902114222.181353-14-aneesh.kumar@linux.ibm.com
Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable/hugetlb: disable hugetlb test on ppc64

2020-10-16T18:11:14+00:00

The seems to be missing quite a lot of details w.r.t allocating the
correct pgtable_t page (huge_pte_alloc()), holding the right lock
(huge_pte_lock()) etc.  The vma used is also not a hugetlb VMA.

ppc64 do have runtime checks within CONFIG_DEBUG_VM for most of these.
Hence disable the test on ppc64.

[anshuman.khandual@arm.com: drop hugetlb_advanced_tests()]
  Link: https://lore.kernel.org/lkml/289c3fdb-1394-c1af-bdc4-5542907089dc@linux.ibm.com/#t
  Link: https://lkml.kernel.org/r/1600914446-21890-1-git-send-email-anshuman.khandual@arm.com

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Anshuman Khandual 
Signed-off-by: Andrew Morton 
Cc: Christophe Leroy 
Cc: Michael Ellerman 
Link: https://lkml.kernel.org/r/20200902114222.181353-13-aneesh.kumar@linux.ibm.com
Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable/pmd_clear: don't use pmd/pud_clear on pte entries

2020-10-16T18:11:14+00:00

pmd_clear() should not be used to clear pmd level pte entries.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Andrew Morton 
Cc: Anshuman Khandual 
Cc: Christophe Leroy 
Cc: Michael Ellerman 
Link: https://lkml.kernel.org/r/20200902114222.181353-12-aneesh.kumar@linux.ibm.com
Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable/thp: use page table depost/withdraw with THP

2020-10-16T18:11:14+00:00

Architectures like ppc64 use deposited page table while updating the huge
pte entries.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Andrew Morton 
Reviewed-by: Anshuman Khandual 
Cc: Christophe Leroy 
Cc: Michael Ellerman 
Link: https://lkml.kernel.org/r/20200902114222.181353-11-aneesh.kumar@linux.ibm.com
Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable/locks: take correct page table lock

2020-10-16T18:11:14+00:00

Make sure we call pte accessors with correct lock held.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Andrew Morton 
Cc: Anshuman Khandual 
Cc: Christophe Leroy 
Cc: Michael Ellerman 
Link: https://lkml.kernel.org/r/20200902114222.181353-10-aneesh.kumar@linux.ibm.com
Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable/locks: move non page table modifying test together

2020-10-16T18:11:14+00:00

This will help in adding proper locks in a later patch

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Andrew Morton 
Cc: Anshuman Khandual 
Cc: Christophe Leroy 
Cc: Michael Ellerman 
Link: https://lkml.kernel.org/r/20200902114222.181353-9-aneesh.kumar@linux.ibm.com
Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable/set_pte/pmd/pud: don't use set_*_at to update an existing pte entry

2020-10-16T18:11:14+00:00

set_pte_at() should not be used to set a pte entry at locations that
already holds a valid pte entry.  Architectures like ppc64 don't do TLB
invalidate in set_pte_at() and hence expect it to be used to set locations
that are not a valid PTE.

Link: https://lkml.kernel.org/r/20200902114222.181353-8-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V 
Reviewed-by: Anshuman Khandual 
Cc: Christophe Leroy 
Cc: Michael Ellerman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds