https://github.com/torvalds/linux
Tip revision: 519d81956ee277b4419c723adfb154603c2565ba authored by Linus Torvalds on 18 October 2021, 06:00:13 UTC
Linux 5.15-rc6
Linux 5.15-rc6
Tip revision: 519d819
arch_pgtable_helpers.rst
.. SPDX-License-Identifier: GPL-2.0
.. _arch_page_table_helpers:
===============================
Architecture Page Table Helpers
===============================
Generic MM expects architectures (with MMU) to provide helpers to create, access
and modify page table entries at various level for different memory functions.
These page table helpers need to conform to a common semantics across platforms.
Following tables describe the expected semantics which can also be tested during
boot via CONFIG_DEBUG_VM_PGTABLE option. All future changes in here or the debug
test need to be in sync.
======================
PTE Page Table Helpers
======================
+---------------------------+--------------------------------------------------+
| pte_same | Tests whether both PTE entries are the same |
+---------------------------+--------------------------------------------------+
| pte_bad | Tests a non-table mapped PTE |
+---------------------------+--------------------------------------------------+
| pte_present | Tests a valid mapped PTE |
+---------------------------+--------------------------------------------------+
| pte_young | Tests a young PTE |
+---------------------------+--------------------------------------------------+
| pte_dirty | Tests a dirty PTE |
+---------------------------+--------------------------------------------------+
| pte_write | Tests a writable PTE |
+---------------------------+--------------------------------------------------+
| pte_special | Tests a special PTE |
+---------------------------+--------------------------------------------------+
| pte_protnone | Tests a PROT_NONE PTE |
+---------------------------+--------------------------------------------------+
| pte_devmap | Tests a ZONE_DEVICE mapped PTE |
+---------------------------+--------------------------------------------------+
| pte_soft_dirty | Tests a soft dirty PTE |
+---------------------------+--------------------------------------------------+
| pte_swp_soft_dirty | Tests a soft dirty swapped PTE |
+---------------------------+--------------------------------------------------+
| pte_mkyoung | Creates a young PTE |
+---------------------------+--------------------------------------------------+
| pte_mkold | Creates an old PTE |
+---------------------------+--------------------------------------------------+
| pte_mkdirty | Creates a dirty PTE |
+---------------------------+--------------------------------------------------+
| pte_mkclean | Creates a clean PTE |
+---------------------------+--------------------------------------------------+
| pte_mkwrite | Creates a writable PTE |
+---------------------------+--------------------------------------------------+
| pte_wrprotect | Creates a write protected PTE |
+---------------------------+--------------------------------------------------+
| pte_mkspecial | Creates a special PTE |
+---------------------------+--------------------------------------------------+
| pte_mkdevmap | Creates a ZONE_DEVICE mapped PTE |
+---------------------------+--------------------------------------------------+
| pte_mksoft_dirty | Creates a soft dirty PTE |
+---------------------------+--------------------------------------------------+
| pte_clear_soft_dirty | Clears a soft dirty PTE |
+---------------------------+--------------------------------------------------+
| pte_swp_mksoft_dirty | Creates a soft dirty swapped PTE |
+---------------------------+--------------------------------------------------+
| pte_swp_clear_soft_dirty | Clears a soft dirty swapped PTE |
+---------------------------+--------------------------------------------------+
| pte_mknotpresent | Invalidates a mapped PTE |
+---------------------------+--------------------------------------------------+
| ptep_get_and_clear | Clears a PTE |
+---------------------------+--------------------------------------------------+
| ptep_get_and_clear_full | Clears a PTE |
+---------------------------+--------------------------------------------------+
| ptep_test_and_clear_young | Clears young from a PTE |
+---------------------------+--------------------------------------------------+
| ptep_set_wrprotect | Converts into a write protected PTE |
+---------------------------+--------------------------------------------------+
| ptep_set_access_flags | Converts into a more permissive PTE |
+---------------------------+--------------------------------------------------+
======================
PMD Page Table Helpers
======================
+---------------------------+--------------------------------------------------+
| pmd_same | Tests whether both PMD entries are the same |
+---------------------------+--------------------------------------------------+
| pmd_bad | Tests a non-table mapped PMD |
+---------------------------+--------------------------------------------------+
| pmd_leaf | Tests a leaf mapped PMD |
+---------------------------+--------------------------------------------------+
| pmd_huge | Tests a HugeTLB mapped PMD |
+---------------------------+--------------------------------------------------+
| pmd_trans_huge | Tests a Transparent Huge Page (THP) at PMD |
+---------------------------+--------------------------------------------------+
| pmd_present | Tests a valid mapped PMD |
+---------------------------+--------------------------------------------------+
| pmd_young | Tests a young PMD |
+---------------------------+--------------------------------------------------+
| pmd_dirty | Tests a dirty PMD |
+---------------------------+--------------------------------------------------+
| pmd_write | Tests a writable PMD |
+---------------------------+--------------------------------------------------+
| pmd_special | Tests a special PMD |
+---------------------------+--------------------------------------------------+
| pmd_protnone | Tests a PROT_NONE PMD |
+---------------------------+--------------------------------------------------+
| pmd_devmap | Tests a ZONE_DEVICE mapped PMD |
+---------------------------+--------------------------------------------------+
| pmd_soft_dirty | Tests a soft dirty PMD |
+---------------------------+--------------------------------------------------+
| pmd_swp_soft_dirty | Tests a soft dirty swapped PMD |
+---------------------------+--------------------------------------------------+
| pmd_mkyoung | Creates a young PMD |
+---------------------------+--------------------------------------------------+
| pmd_mkold | Creates an old PMD |
+---------------------------+--------------------------------------------------+
| pmd_mkdirty | Creates a dirty PMD |
+---------------------------+--------------------------------------------------+
| pmd_mkclean | Creates a clean PMD |
+---------------------------+--------------------------------------------------+
| pmd_mkwrite | Creates a writable PMD |
+---------------------------+--------------------------------------------------+
| pmd_wrprotect | Creates a write protected PMD |
+---------------------------+--------------------------------------------------+
| pmd_mkspecial | Creates a special PMD |
+---------------------------+--------------------------------------------------+
| pmd_mkdevmap | Creates a ZONE_DEVICE mapped PMD |
+---------------------------+--------------------------------------------------+
| pmd_mksoft_dirty | Creates a soft dirty PMD |
+---------------------------+--------------------------------------------------+
| pmd_clear_soft_dirty | Clears a soft dirty PMD |
+---------------------------+--------------------------------------------------+
| pmd_swp_mksoft_dirty | Creates a soft dirty swapped PMD |
+---------------------------+--------------------------------------------------+
| pmd_swp_clear_soft_dirty | Clears a soft dirty swapped PMD |
+---------------------------+--------------------------------------------------+
| pmd_mkinvalid | Invalidates a mapped PMD [1] |
+---------------------------+--------------------------------------------------+
| pmd_set_huge | Creates a PMD huge mapping |
+---------------------------+--------------------------------------------------+
| pmd_clear_huge | Clears a PMD huge mapping |
+---------------------------+--------------------------------------------------+
| pmdp_get_and_clear | Clears a PMD |
+---------------------------+--------------------------------------------------+
| pmdp_get_and_clear_full | Clears a PMD |
+---------------------------+--------------------------------------------------+
| pmdp_test_and_clear_young | Clears young from a PMD |
+---------------------------+--------------------------------------------------+
| pmdp_set_wrprotect | Converts into a write protected PMD |
+---------------------------+--------------------------------------------------+
| pmdp_set_access_flags | Converts into a more permissive PMD |
+---------------------------+--------------------------------------------------+
======================
PUD Page Table Helpers
======================
+---------------------------+--------------------------------------------------+
| pud_same | Tests whether both PUD entries are the same |
+---------------------------+--------------------------------------------------+
| pud_bad | Tests a non-table mapped PUD |
+---------------------------+--------------------------------------------------+
| pud_leaf | Tests a leaf mapped PUD |
+---------------------------+--------------------------------------------------+
| pud_huge | Tests a HugeTLB mapped PUD |
+---------------------------+--------------------------------------------------+
| pud_trans_huge | Tests a Transparent Huge Page (THP) at PUD |
+---------------------------+--------------------------------------------------+
| pud_present | Tests a valid mapped PUD |
+---------------------------+--------------------------------------------------+
| pud_young | Tests a young PUD |
+---------------------------+--------------------------------------------------+
| pud_dirty | Tests a dirty PUD |
+---------------------------+--------------------------------------------------+
| pud_write | Tests a writable PUD |
+---------------------------+--------------------------------------------------+
| pud_devmap | Tests a ZONE_DEVICE mapped PUD |
+---------------------------+--------------------------------------------------+
| pud_mkyoung | Creates a young PUD |
+---------------------------+--------------------------------------------------+
| pud_mkold | Creates an old PUD |
+---------------------------+--------------------------------------------------+
| pud_mkdirty | Creates a dirty PUD |
+---------------------------+--------------------------------------------------+
| pud_mkclean | Creates a clean PUD |
+---------------------------+--------------------------------------------------+
| pud_mkwrite | Creates a writable PUD |
+---------------------------+--------------------------------------------------+
| pud_wrprotect | Creates a write protected PUD |
+---------------------------+--------------------------------------------------+
| pud_mkdevmap | Creates a ZONE_DEVICE mapped PUD |
+---------------------------+--------------------------------------------------+
| pud_mkinvalid | Invalidates a mapped PUD [1] |
+---------------------------+--------------------------------------------------+
| pud_set_huge | Creates a PUD huge mapping |
+---------------------------+--------------------------------------------------+
| pud_clear_huge | Clears a PUD huge mapping |
+---------------------------+--------------------------------------------------+
| pudp_get_and_clear | Clears a PUD |
+---------------------------+--------------------------------------------------+
| pudp_get_and_clear_full | Clears a PUD |
+---------------------------+--------------------------------------------------+
| pudp_test_and_clear_young | Clears young from a PUD |
+---------------------------+--------------------------------------------------+
| pudp_set_wrprotect | Converts into a write protected PUD |
+---------------------------+--------------------------------------------------+
| pudp_set_access_flags | Converts into a more permissive PUD |
+---------------------------+--------------------------------------------------+
==========================
HugeTLB Page Table Helpers
==========================
+---------------------------+--------------------------------------------------+
| pte_huge | Tests a HugeTLB |
+---------------------------+--------------------------------------------------+
| pte_mkhuge | Creates a HugeTLB |
+---------------------------+--------------------------------------------------+
| huge_pte_dirty | Tests a dirty HugeTLB |
+---------------------------+--------------------------------------------------+
| huge_pte_write | Tests a writable HugeTLB |
+---------------------------+--------------------------------------------------+
| huge_pte_mkdirty | Creates a dirty HugeTLB |
+---------------------------+--------------------------------------------------+
| huge_pte_mkwrite | Creates a writable HugeTLB |
+---------------------------+--------------------------------------------------+
| huge_pte_wrprotect | Creates a write protected HugeTLB |
+---------------------------+--------------------------------------------------+
| huge_ptep_get_and_clear | Clears a HugeTLB |
+---------------------------+--------------------------------------------------+
| huge_ptep_set_wrprotect | Converts into a write protected HugeTLB |
+---------------------------+--------------------------------------------------+
| huge_ptep_set_access_flags | Converts into a more permissive HugeTLB |
+---------------------------+--------------------------------------------------+
========================
SWAP Page Table Helpers
========================
+---------------------------+--------------------------------------------------+
| __pte_to_swp_entry | Creates a swapped entry (arch) from a mapped PTE |
+---------------------------+--------------------------------------------------+
| __swp_to_pte_entry | Creates a mapped PTE from a swapped entry (arch) |
+---------------------------+--------------------------------------------------+
| __pmd_to_swp_entry | Creates a swapped entry (arch) from a mapped PMD |
+---------------------------+--------------------------------------------------+
| __swp_to_pmd_entry | Creates a mapped PMD from a swapped entry (arch) |
+---------------------------+--------------------------------------------------+
| is_migration_entry | Tests a migration (read or write) swapped entry |
+---------------------------+--------------------------------------------------+
| is_write_migration_entry | Tests a write migration swapped entry |
+---------------------------+--------------------------------------------------+
| make_migration_entry_read | Converts into read migration swapped entry |
+---------------------------+--------------------------------------------------+
| make_migration_entry | Creates a migration swapped entry (read or write)|
+---------------------------+--------------------------------------------------+
[1] https://lore.kernel.org/linux-mm/20181017020930.GN30832@redhat.com/