bb5c47ced4
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 <anshuman.khandual@arm.com> Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390] Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Steven Price <steven.price@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
259 lines
18 KiB
ReStructuredText
259 lines
18 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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.. _arch_page_table_helpers:
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===============================
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Architecture Page Table Helpers
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===============================
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Generic MM expects architectures (with MMU) to provide helpers to create, access
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and modify page table entries at various level for different memory functions.
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These page table helpers need to conform to a common semantics across platforms.
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Following tables describe the expected semantics which can also be tested during
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boot via CONFIG_DEBUG_VM_PGTABLE option. All future changes in here or the debug
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test need to be in sync.
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======================
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PTE Page Table Helpers
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======================
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+---------------------------+--------------------------------------------------+
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| pte_same | Tests whether both PTE entries are the same |
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+---------------------------+--------------------------------------------------+
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| pte_bad | Tests a non-table mapped PTE |
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+---------------------------+--------------------------------------------------+
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| pte_present | Tests a valid mapped PTE |
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+---------------------------+--------------------------------------------------+
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| pte_young | Tests a young PTE |
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+---------------------------+--------------------------------------------------+
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| pte_dirty | Tests a dirty PTE |
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+---------------------------+--------------------------------------------------+
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| pte_write | Tests a writable PTE |
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+---------------------------+--------------------------------------------------+
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| pte_special | Tests a special PTE |
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+---------------------------+--------------------------------------------------+
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| pte_protnone | Tests a PROT_NONE PTE |
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+---------------------------+--------------------------------------------------+
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| pte_devmap | Tests a ZONE_DEVICE mapped PTE |
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+---------------------------+--------------------------------------------------+
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| pte_soft_dirty | Tests a soft dirty PTE |
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+---------------------------+--------------------------------------------------+
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| pte_swp_soft_dirty | Tests a soft dirty swapped PTE |
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+---------------------------+--------------------------------------------------+
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| pte_mkyoung | Creates a young PTE |
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+---------------------------+--------------------------------------------------+
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| pte_mkold | Creates an old PTE |
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+---------------------------+--------------------------------------------------+
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| pte_mkdirty | Creates a dirty PTE |
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+---------------------------+--------------------------------------------------+
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| pte_mkclean | Creates a clean PTE |
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+---------------------------+--------------------------------------------------+
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| pte_mkwrite | Creates a writable PTE |
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+---------------------------+--------------------------------------------------+
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| pte_wrprotect | Creates a write protected PTE |
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+---------------------------+--------------------------------------------------+
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| pte_mkspecial | Creates a special PTE |
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+---------------------------+--------------------------------------------------+
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| pte_mkdevmap | Creates a ZONE_DEVICE mapped PTE |
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+---------------------------+--------------------------------------------------+
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| pte_mksoft_dirty | Creates a soft dirty PTE |
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+---------------------------+--------------------------------------------------+
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| pte_clear_soft_dirty | Clears a soft dirty PTE |
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+---------------------------+--------------------------------------------------+
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| pte_swp_mksoft_dirty | Creates a soft dirty swapped PTE |
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+---------------------------+--------------------------------------------------+
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| pte_swp_clear_soft_dirty | Clears a soft dirty swapped PTE |
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+---------------------------+--------------------------------------------------+
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| pte_mknotpresent | Invalidates a mapped PTE |
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+---------------------------+--------------------------------------------------+
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| ptep_get_and_clear | Clears a PTE |
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+---------------------------+--------------------------------------------------+
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| ptep_get_and_clear_full | Clears a PTE |
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+---------------------------+--------------------------------------------------+
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| ptep_test_and_clear_young | Clears young from a PTE |
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+---------------------------+--------------------------------------------------+
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| ptep_set_wrprotect | Converts into a write protected PTE |
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+---------------------------+--------------------------------------------------+
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| ptep_set_access_flags | Converts into a more permissive PTE |
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+---------------------------+--------------------------------------------------+
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======================
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PMD Page Table Helpers
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======================
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+---------------------------+--------------------------------------------------+
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| pmd_same | Tests whether both PMD entries are the same |
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+---------------------------+--------------------------------------------------+
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| pmd_bad | Tests a non-table mapped PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_leaf | Tests a leaf mapped PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_huge | Tests a HugeTLB mapped PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_trans_huge | Tests a Transparent Huge Page (THP) at PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_present | Tests a valid mapped PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_young | Tests a young PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_dirty | Tests a dirty PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_write | Tests a writable PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_special | Tests a special PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_protnone | Tests a PROT_NONE PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_devmap | Tests a ZONE_DEVICE mapped PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_soft_dirty | Tests a soft dirty PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_swp_soft_dirty | Tests a soft dirty swapped PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_mkyoung | Creates a young PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_mkold | Creates an old PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_mkdirty | Creates a dirty PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_mkclean | Creates a clean PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_mkwrite | Creates a writable PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_wrprotect | Creates a write protected PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_mkspecial | Creates a special PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_mkdevmap | Creates a ZONE_DEVICE mapped PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_mksoft_dirty | Creates a soft dirty PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_clear_soft_dirty | Clears a soft dirty PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_swp_mksoft_dirty | Creates a soft dirty swapped PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_swp_clear_soft_dirty | Clears a soft dirty swapped PMD |
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+---------------------------+--------------------------------------------------+
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| pmd_mkinvalid | Invalidates a mapped PMD [1] |
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+---------------------------+--------------------------------------------------+
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| pmd_set_huge | Creates a PMD huge mapping |
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+---------------------------+--------------------------------------------------+
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| pmd_clear_huge | Clears a PMD huge mapping |
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+---------------------------+--------------------------------------------------+
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| pmdp_get_and_clear | Clears a PMD |
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+---------------------------+--------------------------------------------------+
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| pmdp_get_and_clear_full | Clears a PMD |
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+---------------------------+--------------------------------------------------+
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| pmdp_test_and_clear_young | Clears young from a PMD |
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+---------------------------+--------------------------------------------------+
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| pmdp_set_wrprotect | Converts into a write protected PMD |
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+---------------------------+--------------------------------------------------+
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| pmdp_set_access_flags | Converts into a more permissive PMD |
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+---------------------------+--------------------------------------------------+
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======================
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PUD Page Table Helpers
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======================
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+---------------------------+--------------------------------------------------+
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| pud_same | Tests whether both PUD entries are the same |
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+---------------------------+--------------------------------------------------+
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| pud_bad | Tests a non-table mapped PUD |
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+---------------------------+--------------------------------------------------+
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| pud_leaf | Tests a leaf mapped PUD |
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+---------------------------+--------------------------------------------------+
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| pud_huge | Tests a HugeTLB mapped PUD |
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+---------------------------+--------------------------------------------------+
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| pud_trans_huge | Tests a Transparent Huge Page (THP) at PUD |
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+---------------------------+--------------------------------------------------+
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| pud_present | Tests a valid mapped PUD |
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+---------------------------+--------------------------------------------------+
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| pud_young | Tests a young PUD |
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+---------------------------+--------------------------------------------------+
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| pud_dirty | Tests a dirty PUD |
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+---------------------------+--------------------------------------------------+
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| pud_write | Tests a writable PUD |
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+---------------------------+--------------------------------------------------+
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| pud_devmap | Tests a ZONE_DEVICE mapped PUD |
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+---------------------------+--------------------------------------------------+
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| pud_mkyoung | Creates a young PUD |
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+---------------------------+--------------------------------------------------+
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| pud_mkold | Creates an old PUD |
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+---------------------------+--------------------------------------------------+
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| pud_mkdirty | Creates a dirty PUD |
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+---------------------------+--------------------------------------------------+
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| pud_mkclean | Creates a clean PUD |
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+---------------------------+--------------------------------------------------+
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| pud_mkwrite | Creates a writable PUD |
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+---------------------------+--------------------------------------------------+
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| pud_wrprotect | Creates a write protected PUD |
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+---------------------------+--------------------------------------------------+
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| pud_mkdevmap | Creates a ZONE_DEVICE mapped PUD |
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+---------------------------+--------------------------------------------------+
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| pud_mkinvalid | Invalidates a mapped PUD [1] |
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+---------------------------+--------------------------------------------------+
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| pud_set_huge | Creates a PUD huge mapping |
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+---------------------------+--------------------------------------------------+
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| pud_clear_huge | Clears a PUD huge mapping |
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+---------------------------+--------------------------------------------------+
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| pudp_get_and_clear | Clears a PUD |
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+---------------------------+--------------------------------------------------+
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| pudp_get_and_clear_full | Clears a PUD |
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+---------------------------+--------------------------------------------------+
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| pudp_test_and_clear_young | Clears young from a PUD |
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+---------------------------+--------------------------------------------------+
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| pudp_set_wrprotect | Converts into a write protected PUD |
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+---------------------------+--------------------------------------------------+
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| pudp_set_access_flags | Converts into a more permissive PUD |
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+---------------------------+--------------------------------------------------+
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==========================
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HugeTLB Page Table Helpers
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==========================
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+---------------------------+--------------------------------------------------+
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| pte_huge | Tests a HugeTLB |
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+---------------------------+--------------------------------------------------+
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| pte_mkhuge | Creates a HugeTLB |
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+---------------------------+--------------------------------------------------+
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| huge_pte_dirty | Tests a dirty HugeTLB |
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+---------------------------+--------------------------------------------------+
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| huge_pte_write | Tests a writable HugeTLB |
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+---------------------------+--------------------------------------------------+
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| huge_pte_mkdirty | Creates a dirty HugeTLB |
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+---------------------------+--------------------------------------------------+
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| huge_pte_mkwrite | Creates a writable HugeTLB |
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+---------------------------+--------------------------------------------------+
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| huge_pte_wrprotect | Creates a write protected HugeTLB |
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+---------------------------+--------------------------------------------------+
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| huge_ptep_get_and_clear | Clears a HugeTLB |
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+---------------------------+--------------------------------------------------+
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| huge_ptep_set_wrprotect | Converts into a write protected HugeTLB |
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+---------------------------+--------------------------------------------------+
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| huge_ptep_set_access_flags | Converts into a more permissive HugeTLB |
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+---------------------------+--------------------------------------------------+
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========================
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SWAP Page Table Helpers
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========================
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+---------------------------+--------------------------------------------------+
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| __pte_to_swp_entry | Creates a swapped entry (arch) from a mapped PTE |
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+---------------------------+--------------------------------------------------+
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| __swp_to_pte_entry | Creates a mapped PTE from a swapped entry (arch) |
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+---------------------------+--------------------------------------------------+
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| __pmd_to_swp_entry | Creates a swapped entry (arch) from a mapped PMD |
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+---------------------------+--------------------------------------------------+
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| __swp_to_pmd_entry | Creates a mapped PMD from a swapped entry (arch) |
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+---------------------------+--------------------------------------------------+
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| is_migration_entry | Tests a migration (read or write) swapped entry |
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+---------------------------+--------------------------------------------------+
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| is_write_migration_entry | Tests a write migration swapped entry |
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+---------------------------+--------------------------------------------------+
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| make_migration_entry_read | Converts into read migration swapped entry |
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+---------------------------+--------------------------------------------------+
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| make_migration_entry | Creates a migration swapped entry (read or write)|
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+---------------------------+--------------------------------------------------+
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[1] https://lore.kernel.org/linux-mm/20181017020930.GN30832@redhat.com/
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