diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/leafops.h | 387 | ||||
| -rw-r--r-- | include/linux/mm_inline.h | 6 | ||||
| -rw-r--r-- | include/linux/mm_types.h | 25 | ||||
| -rw-r--r-- | include/linux/swapops.h | 28 | ||||
| -rw-r--r-- | include/linux/userfaultfd_k.h | 51 |
5 files changed, 417 insertions, 80 deletions
diff --git a/include/linux/leafops.h b/include/linux/leafops.h new file mode 100644 index 000000000000..cff9d94fd5d1 --- /dev/null +++ b/include/linux/leafops.h @@ -0,0 +1,387 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Describes operations that can be performed on software-defined page table + * leaf entries. These are abstracted from the hardware page table entries + * themselves by the softleaf_t type, see mm_types.h. + */ +#ifndef _LINUX_LEAFOPS_H +#define _LINUX_LEAFOPS_H + +#include <linux/mm_types.h> +#include <linux/swapops.h> +#include <linux/swap.h> + +#ifdef CONFIG_MMU + +/* Temporary until swp_entry_t eliminated. */ +#define LEAF_TYPE_SHIFT SWP_TYPE_SHIFT + +enum softleaf_type { + /* Fundamental types. */ + SOFTLEAF_NONE, + SOFTLEAF_SWAP, + /* Migration types. */ + SOFTLEAF_MIGRATION_READ, + SOFTLEAF_MIGRATION_READ_EXCLUSIVE, + SOFTLEAF_MIGRATION_WRITE, + /* Device types. */ + SOFTLEAF_DEVICE_PRIVATE_READ, + SOFTLEAF_DEVICE_PRIVATE_WRITE, + SOFTLEAF_DEVICE_EXCLUSIVE, + /* H/W posion types. */ + SOFTLEAF_HWPOISON, + /* Marker types. */ + SOFTLEAF_MARKER, +}; + +/** + * softleaf_mk_none() - Create an empty ('none') leaf entry. + * Returns: empty leaf entry. + */ +static inline softleaf_t softleaf_mk_none(void) +{ + return ((softleaf_t) { 0 }); +} + +/** + * softleaf_from_pte() - Obtain a leaf entry from a PTE entry. + * @pte: PTE entry. + * + * If @pte is present (therefore not a leaf entry) the function returns an empty + * leaf entry. Otherwise, it returns a leaf entry. + * + * Returns: Leaf entry. + */ +static inline softleaf_t softleaf_from_pte(pte_t pte) +{ + if (pte_present(pte) || pte_none(pte)) + return softleaf_mk_none(); + + /* Temporary until swp_entry_t eliminated. */ + return pte_to_swp_entry(pte); +} + +/** + * softleaf_is_none() - Is the leaf entry empty? + * @entry: Leaf entry. + * + * Empty entries are typically the result of a 'none' page table leaf entry + * being converted to a leaf entry. + * + * Returns: true if the entry is empty, false otherwise. + */ +static inline bool softleaf_is_none(softleaf_t entry) +{ + return entry.val == 0; +} + +/** + * softleaf_type() - Identify the type of leaf entry. + * @enntry: Leaf entry. + * + * Returns: the leaf entry type associated with @entry. + */ +static inline enum softleaf_type softleaf_type(softleaf_t entry) +{ + unsigned int type_num; + + if (softleaf_is_none(entry)) + return SOFTLEAF_NONE; + + type_num = entry.val >> LEAF_TYPE_SHIFT; + + if (type_num < MAX_SWAPFILES) + return SOFTLEAF_SWAP; + + switch (type_num) { +#ifdef CONFIG_MIGRATION + case SWP_MIGRATION_READ: + return SOFTLEAF_MIGRATION_READ; + case SWP_MIGRATION_READ_EXCLUSIVE: + return SOFTLEAF_MIGRATION_READ_EXCLUSIVE; + case SWP_MIGRATION_WRITE: + return SOFTLEAF_MIGRATION_WRITE; +#endif +#ifdef CONFIG_DEVICE_PRIVATE + case SWP_DEVICE_WRITE: + return SOFTLEAF_DEVICE_PRIVATE_WRITE; + case SWP_DEVICE_READ: + return SOFTLEAF_DEVICE_PRIVATE_READ; + case SWP_DEVICE_EXCLUSIVE: + return SOFTLEAF_DEVICE_EXCLUSIVE; +#endif +#ifdef CONFIG_MEMORY_FAILURE + case SWP_HWPOISON: + return SOFTLEAF_HWPOISON; +#endif + case SWP_PTE_MARKER: + return SOFTLEAF_MARKER; + } + + /* Unknown entry type. */ + VM_WARN_ON_ONCE(1); + return SOFTLEAF_NONE; +} + +/** + * softleaf_is_swap() - Is this leaf entry a swap entry? + * @entry: Leaf entry. + * + * Returns: true if the leaf entry is a swap entry, otherwise false. + */ +static inline bool softleaf_is_swap(softleaf_t entry) +{ + return softleaf_type(entry) == SOFTLEAF_SWAP; +} + +/** + * softleaf_is_migration() - Is this leaf entry a migration entry? + * @entry: Leaf entry. + * + * Returns: true if the leaf entry is a migration entry, otherwise false. + */ +static inline bool softleaf_is_migration(softleaf_t entry) +{ + switch (softleaf_type(entry)) { + case SOFTLEAF_MIGRATION_READ: + case SOFTLEAF_MIGRATION_READ_EXCLUSIVE: + case SOFTLEAF_MIGRATION_WRITE: + return true; + default: + return false; + } +} + +/** + * softleaf_is_device_private() - Is this leaf entry a device private entry? + * @entry: Leaf entry. + * + * Returns: true if the leaf entry is a device private entry, otherwise false. + */ +static inline bool softleaf_is_device_private(softleaf_t entry) +{ + switch (softleaf_type(entry)) { + case SOFTLEAF_DEVICE_PRIVATE_WRITE: + case SOFTLEAF_DEVICE_PRIVATE_READ: + return true; + default: + return false; + } +} + +/** + * softleaf_is_device_exclusive() - Is this leaf entry a device exclusive entry? + * @entry: Leaf entry. + * + * Returns: true if the leaf entry is a device exclusive entry, otherwise false. + */ +static inline bool softleaf_is_device_exclusive(softleaf_t entry) +{ + return softleaf_type(entry) == SOFTLEAF_DEVICE_EXCLUSIVE; +} + +/** + * softleaf_is_hwpoison() - Is this leaf entry a hardware poison entry? + * @entry: Leaf entry. + * + * Returns: true if the leaf entry is a hardware poison entry, otherwise false. + */ +static inline bool softleaf_is_hwpoison(softleaf_t entry) +{ + return softleaf_type(entry) == SOFTLEAF_HWPOISON; +} + +/** + * softleaf_is_marker() - Is this leaf entry a marker? + * @entry: Leaf entry. + * + * Returns: true if the leaf entry is a marker entry, otherwise false. + */ +static inline bool softleaf_is_marker(softleaf_t entry) +{ + return softleaf_type(entry) == SOFTLEAF_MARKER; +} + +/** + * softleaf_to_marker() - Obtain marker associated with leaf entry. + * @entry: Leaf entry, softleaf_is_marker(@entry) must return true. + * + * Returns: Marker associated with the leaf entry. + */ +static inline pte_marker softleaf_to_marker(softleaf_t entry) +{ + VM_WARN_ON_ONCE(!softleaf_is_marker(entry)); + + return swp_offset(entry) & PTE_MARKER_MASK; +} + +/** + * softleaf_has_pfn() - Does this leaf entry encode a valid PFN number? + * @entry: Leaf entry. + * + * A pfn swap entry is a special type of swap entry that always has a pfn stored + * in the swap offset. They can either be used to represent unaddressable device + * memory, to restrict access to a page undergoing migration or to represent a + * pfn which has been hwpoisoned and unmapped. + * + * Returns: true if the leaf entry encodes a PFN, otherwise false. + */ +static inline bool softleaf_has_pfn(softleaf_t entry) +{ + /* Make sure the swp offset can always store the needed fields. */ + BUILD_BUG_ON(SWP_TYPE_SHIFT < SWP_PFN_BITS); + + if (softleaf_is_migration(entry)) + return true; + if (softleaf_is_device_private(entry)) + return true; + if (softleaf_is_device_exclusive(entry)) + return true; + if (softleaf_is_hwpoison(entry)) + return true; + + return false; +} + +/** + * softleaf_to_pfn() - Obtain PFN encoded within leaf entry. + * @entry: Leaf entry, softleaf_has_pfn(@entry) must return true. + * + * Returns: The PFN associated with the leaf entry. + */ +static inline unsigned long softleaf_to_pfn(softleaf_t entry) +{ + VM_WARN_ON_ONCE(!softleaf_has_pfn(entry)); + + /* Temporary until swp_entry_t eliminated. */ + return swp_offset_pfn(entry); +} + +/** + * softleaf_to_page() - Obtains struct page for PFN encoded within leaf entry. + * @entry: Leaf entry, softleaf_has_pfn(@entry) must return true. + * + * Returns: Pointer to the struct page associated with the leaf entry's PFN. + */ +static inline struct page *softleaf_to_page(softleaf_t entry) +{ + VM_WARN_ON_ONCE(!softleaf_has_pfn(entry)); + + /* Temporary until swp_entry_t eliminated. */ + return pfn_swap_entry_to_page(entry); +} + +/** + * softleaf_to_folio() - Obtains struct folio for PFN encoded within leaf entry. + * @entry: Leaf entry, softleaf_has_pfn(@entry) must return true. + * + * Returns: Pointer to the struct folio associated with the leaf entry's PFN. + */ +static inline struct folio *softleaf_to_folio(softleaf_t entry) +{ + VM_WARN_ON_ONCE(!softleaf_has_pfn(entry)); + + /* Temporary until swp_entry_t eliminated. */ + return pfn_swap_entry_folio(entry); +} + +/** + * softleaf_is_poison_marker() - Is this leaf entry a poison marker? + * @entry: Leaf entry. + * + * The poison marker is set via UFFDIO_POISON. Userfaultfd-specific. + * + * Returns: true if the leaf entry is a poison marker, otherwise false. + */ +static inline bool softleaf_is_poison_marker(softleaf_t entry) +{ + if (!softleaf_is_marker(entry)) + return false; + + return softleaf_to_marker(entry) & PTE_MARKER_POISONED; +} + +/** + * softleaf_is_guard_marker() - Is this leaf entry a guard region marker? + * @entry: Leaf entry. + * + * Returns: true if the leaf entry is a guard marker, otherwise false. + */ +static inline bool softleaf_is_guard_marker(softleaf_t entry) +{ + if (!softleaf_is_marker(entry)) + return false; + + return softleaf_to_marker(entry) & PTE_MARKER_GUARD; +} + +/** + * softleaf_is_uffd_wp_marker() - Is this leaf entry a userfautlfd write protect + * marker? + * @entry: Leaf entry. + * + * Userfaultfd-specific. + * + * Returns: true if the leaf entry is a UFFD WP marker, otherwise false. + */ +static inline bool softleaf_is_uffd_wp_marker(softleaf_t entry) +{ + if (!softleaf_is_marker(entry)) + return false; + + return softleaf_to_marker(entry) & PTE_MARKER_UFFD_WP; +} + +/** + * pte_is_marker() - Does the PTE entry encode a marker leaf entry? + * @pte: PTE entry. + * + * Returns: true if this PTE is a marker leaf entry, otherwise false. + */ +static inline bool pte_is_marker(pte_t pte) +{ + return softleaf_is_marker(softleaf_from_pte(pte)); +} + +/** + * pte_is_uffd_wp_marker() - Does this PTE entry encode a userfaultfd write + * protect marker leaf entry? + * @pte: PTE entry. + * + * Returns: true if this PTE is a UFFD WP marker leaf entry, otherwise false. + */ +static inline bool pte_is_uffd_wp_marker(pte_t pte) +{ + const softleaf_t entry = softleaf_from_pte(pte); + + return softleaf_is_uffd_wp_marker(entry); +} + +/** + * pte_is_uffd_marker() - Does this PTE entry encode a userfault-specific marker + * leaf entry? + * @entry: Leaf entry. + * + * It's useful to be able to determine which leaf entries encode UFFD-specific + * markers so we can handle these correctly. + * + * Returns: true if this PTE entry is a UFFD-specific marker, otherwise false. + */ +static inline bool pte_is_uffd_marker(pte_t pte) +{ + const softleaf_t entry = softleaf_from_pte(pte); + + if (!softleaf_is_marker(entry)) + return false; + + /* UFFD WP, poisoned swap entries are UFFD-handled. */ + if (softleaf_is_uffd_wp_marker(entry)) + return true; + if (softleaf_is_poison_marker(entry)) + return true; + + return false; +} + +#endif /* CONFIG_MMU */ +#endif /* _LINUX_LEAFOPS_H */ diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h index f6a2b2d20016..ca7a18351797 100644 --- a/include/linux/mm_inline.h +++ b/include/linux/mm_inline.h @@ -8,7 +8,7 @@ #include <linux/swap.h> #include <linux/string.h> #include <linux/userfaultfd_k.h> -#include <linux/swapops.h> +#include <linux/leafops.h> /** * folio_is_file_lru - Should the folio be on a file LRU or anon LRU? @@ -541,9 +541,9 @@ static inline bool mm_tlb_flush_nested(const struct mm_struct *mm) * The caller should insert a new pte created with make_pte_marker(). */ static inline pte_marker copy_pte_marker( - swp_entry_t entry, struct vm_area_struct *dst_vma) + softleaf_t entry, struct vm_area_struct *dst_vma) { - pte_marker srcm = pte_marker_get(entry); + const pte_marker srcm = softleaf_to_marker(entry); /* Always copy error entries. */ pte_marker dstm = srcm & (PTE_MARKER_POISONED | PTE_MARKER_GUARD); diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 5021047485a9..4f66a3206a63 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -285,6 +285,31 @@ typedef struct { unsigned long val; } swp_entry_t; +/** + * typedef softleaf_t - Describes a page table software leaf entry, abstracted + * from its architecture-specific encoding. + * + * Page table leaf entries are those which do not reference any descendent page + * tables but rather either reference a data page, are an empty (or 'none' + * entry), or contain a non-present entry. + * + * If referencing another page table or a data page then the page table entry is + * pertinent to hardware - that is it tells the hardware how to decode the page + * table entry. + * + * Otherwise it is a software-defined leaf page table entry, which this type + * describes. See leafops.h and specifically @softleaf_type for a list of all + * possible kinds of software leaf entry. + * + * A softleaf_t entry is abstracted from the hardware page table entry, so is + * not architecture-specific. + * + * NOTE: While we transition from the confusing swp_entry_t type used for this + * purpose, we simply alias this type. This will be removed once the + * transition is complete. + */ +typedef swp_entry_t softleaf_t; + #if defined(CONFIG_MEMCG) || defined(CONFIG_SLAB_OBJ_EXT) /* We have some extra room after the refcount in tail pages. */ #define NR_PAGES_IN_LARGE_FOLIO diff --git a/include/linux/swapops.h b/include/linux/swapops.h index d1f665935cfc..0a4b3f51ecf5 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -426,21 +426,6 @@ static inline swp_entry_t make_pte_marker_entry(pte_marker marker) return swp_entry(SWP_PTE_MARKER, marker); } -static inline bool is_pte_marker_entry(swp_entry_t entry) -{ - return swp_type(entry) == SWP_PTE_MARKER; -} - -static inline pte_marker pte_marker_get(swp_entry_t entry) -{ - return swp_offset(entry) & PTE_MARKER_MASK; -} - -static inline bool is_pte_marker(pte_t pte) -{ - return is_swap_pte(pte) && is_pte_marker_entry(pte_to_swp_entry(pte)); -} - static inline pte_t make_pte_marker(pte_marker marker) { return swp_entry_to_pte(make_pte_marker_entry(marker)); @@ -451,24 +436,11 @@ static inline swp_entry_t make_poisoned_swp_entry(void) return make_pte_marker_entry(PTE_MARKER_POISONED); } -static inline int is_poisoned_swp_entry(swp_entry_t entry) -{ - return is_pte_marker_entry(entry) && - (pte_marker_get(entry) & PTE_MARKER_POISONED); - -} - static inline swp_entry_t make_guard_swp_entry(void) { return make_pte_marker_entry(PTE_MARKER_GUARD); } -static inline int is_guard_swp_entry(swp_entry_t entry) -{ - return is_pte_marker_entry(entry) && - (pte_marker_get(entry) & PTE_MARKER_GUARD); -} - static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry) { struct page *p = pfn_to_page(swp_offset_pfn(entry)); diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index da0b4fcc566f..983c860a00f1 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -16,7 +16,7 @@ #include <linux/fcntl.h> #include <linux/mm.h> #include <linux/swap.h> -#include <linux/swapops.h> +#include <linux/leafops.h> #include <asm-generic/pgtable_uffd.h> #include <linux/hugetlb_inline.h> @@ -434,32 +434,6 @@ static inline bool userfaultfd_wp_use_markers(struct vm_area_struct *vma) return userfaultfd_wp_unpopulated(vma); } -static inline bool pte_marker_entry_uffd_wp(swp_entry_t entry) -{ -#ifdef CONFIG_PTE_MARKER_UFFD_WP - return is_pte_marker_entry(entry) && - (pte_marker_get(entry) & PTE_MARKER_UFFD_WP); -#else - return false; -#endif -} - -static inline bool pte_marker_uffd_wp(pte_t pte) -{ -#ifdef CONFIG_PTE_MARKER_UFFD_WP - swp_entry_t entry; - - if (!is_swap_pte(pte)) - return false; - - entry = pte_to_swp_entry(pte); - - return pte_marker_entry_uffd_wp(entry); -#else - return false; -#endif -} - /* * Returns true if this is a swap pte and was uffd-wp wr-protected in either * forms (pte marker or a normal swap pte), false otherwise. @@ -473,31 +447,10 @@ static inline bool pte_swp_uffd_wp_any(pte_t pte) if (pte_swp_uffd_wp(pte)) return true; - if (pte_marker_uffd_wp(pte)) + if (pte_is_uffd_wp_marker(pte)) return true; #endif return false; } - -static inline bool is_uffd_pte_marker(pte_t pte) -{ - swp_entry_t entry; - - if (pte_present(pte)) - return false; - - entry = pte_to_swp_entry(pte); - if (!is_pte_marker_entry(entry)) - return false; - - /* UFFD WP, poisoned swap entries are UFFD handled. */ - if (pte_marker_entry_uffd_wp(entry)) - return true; - if (is_poisoned_swp_entry(entry)) - return true; - - return false; -} - #endif /* _LINUX_USERFAULTFD_K_H */ |