324 lines
8.4 KiB
C
324 lines
8.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* include/linux/userfaultfd_k.h
|
|
*
|
|
* Copyright (C) 2015 Red Hat, Inc.
|
|
*
|
|
*/
|
|
|
|
#ifndef _LINUX_USERFAULTFD_K_H
|
|
#define _LINUX_USERFAULTFD_K_H
|
|
|
|
#ifdef CONFIG_USERFAULTFD
|
|
|
|
#include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */
|
|
|
|
#include <linux/fcntl.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/swapops.h>
|
|
#include <asm-generic/pgtable_uffd.h>
|
|
#include <linux/hugetlb_inline.h>
|
|
|
|
/* The set of all possible UFFD-related VM flags. */
|
|
#define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_WP | VM_UFFD_MINOR)
|
|
|
|
/*
|
|
* CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
|
|
* new flags, since they might collide with O_* ones. We want
|
|
* to re-use O_* flags that couldn't possibly have a meaning
|
|
* from userfaultfd, in order to leave a free define-space for
|
|
* shared O_* flags.
|
|
*/
|
|
#define UFFD_CLOEXEC O_CLOEXEC
|
|
#define UFFD_NONBLOCK O_NONBLOCK
|
|
|
|
#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
|
|
#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
|
|
|
|
extern int sysctl_unprivileged_userfaultfd;
|
|
|
|
extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason);
|
|
|
|
/*
|
|
* The mode of operation for __mcopy_atomic and its helpers.
|
|
*
|
|
* This is almost an implementation detail (mcopy_atomic below doesn't take this
|
|
* as a parameter), but it's exposed here because memory-kind-specific
|
|
* implementations (e.g. hugetlbfs) need to know the mode of operation.
|
|
*/
|
|
enum mcopy_atomic_mode {
|
|
/* A normal copy_from_user into the destination range. */
|
|
MCOPY_ATOMIC_NORMAL,
|
|
/* Don't copy; map the destination range to the zero page. */
|
|
MCOPY_ATOMIC_ZEROPAGE,
|
|
/* Just install pte(s) with the existing page(s) in the page cache. */
|
|
MCOPY_ATOMIC_CONTINUE,
|
|
};
|
|
|
|
extern int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
|
|
struct vm_area_struct *dst_vma,
|
|
unsigned long dst_addr, struct page *page,
|
|
bool newly_allocated, bool wp_copy);
|
|
|
|
extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
|
|
unsigned long src_start, unsigned long len,
|
|
atomic_t *mmap_changing, __u64 mode);
|
|
extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
|
|
unsigned long dst_start,
|
|
unsigned long len,
|
|
atomic_t *mmap_changing);
|
|
extern ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long dst_start,
|
|
unsigned long len, atomic_t *mmap_changing);
|
|
extern int mwriteprotect_range(struct mm_struct *dst_mm,
|
|
unsigned long start, unsigned long len,
|
|
bool enable_wp, atomic_t *mmap_changing);
|
|
|
|
/* mm helpers */
|
|
static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
|
|
struct vm_userfaultfd_ctx vm_ctx)
|
|
{
|
|
return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
|
|
}
|
|
|
|
/*
|
|
* Never enable huge pmd sharing on some uffd registered vmas:
|
|
*
|
|
* - VM_UFFD_WP VMAs, because write protect information is per pgtable entry.
|
|
*
|
|
* - VM_UFFD_MINOR VMAs, because otherwise we would never get minor faults for
|
|
* VMAs which share huge pmds. (If you have two mappings to the same
|
|
* underlying pages, and fault in the non-UFFD-registered one with a write,
|
|
* with huge pmd sharing this would *also* setup the second UFFD-registered
|
|
* mapping, and we'd not get minor faults.)
|
|
*/
|
|
static inline bool uffd_disable_huge_pmd_share(struct vm_area_struct *vma)
|
|
{
|
|
return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR);
|
|
}
|
|
|
|
/*
|
|
* Don't do fault around for either WP or MINOR registered uffd range. For
|
|
* MINOR registered range, fault around will be a total disaster and ptes can
|
|
* be installed without notifications; for WP it should mostly be fine as long
|
|
* as the fault around checks for pte_none() before the installation, however
|
|
* to be super safe we just forbid it.
|
|
*/
|
|
static inline bool uffd_disable_fault_around(struct vm_area_struct *vma)
|
|
{
|
|
return vma->vm_flags & (VM_UFFD_WP | VM_UFFD_MINOR);
|
|
}
|
|
|
|
static inline bool userfaultfd_missing(struct vm_area_struct *vma)
|
|
{
|
|
return vma->vm_flags & VM_UFFD_MISSING;
|
|
}
|
|
|
|
static inline bool userfaultfd_wp(struct vm_area_struct *vma)
|
|
{
|
|
return vma->vm_flags & VM_UFFD_WP;
|
|
}
|
|
|
|
static inline bool userfaultfd_minor(struct vm_area_struct *vma)
|
|
{
|
|
return vma->vm_flags & VM_UFFD_MINOR;
|
|
}
|
|
|
|
static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
|
|
pte_t pte)
|
|
{
|
|
return userfaultfd_wp(vma) && pte_uffd_wp(pte);
|
|
}
|
|
|
|
static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
|
|
pmd_t pmd)
|
|
{
|
|
return userfaultfd_wp(vma) && pmd_uffd_wp(pmd);
|
|
}
|
|
|
|
static inline bool userfaultfd_armed(struct vm_area_struct *vma)
|
|
{
|
|
return vma->vm_flags & __VM_UFFD_FLAGS;
|
|
}
|
|
|
|
static inline bool vma_can_userfault(struct vm_area_struct *vma,
|
|
unsigned long vm_flags)
|
|
{
|
|
if (vm_flags & VM_UFFD_MINOR)
|
|
return is_vm_hugetlb_page(vma) || vma_is_shmem(vma);
|
|
|
|
#ifndef CONFIG_PTE_MARKER_UFFD_WP
|
|
/*
|
|
* If user requested uffd-wp but not enabled pte markers for
|
|
* uffd-wp, then shmem & hugetlbfs are not supported but only
|
|
* anonymous.
|
|
*/
|
|
if ((vm_flags & VM_UFFD_WP) && !vma_is_anonymous(vma))
|
|
return false;
|
|
#endif
|
|
return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
|
|
vma_is_shmem(vma);
|
|
}
|
|
|
|
extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
|
|
extern void dup_userfaultfd_complete(struct list_head *);
|
|
|
|
extern void mremap_userfaultfd_prep(struct vm_area_struct *,
|
|
struct vm_userfaultfd_ctx *);
|
|
extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
|
|
unsigned long from, unsigned long to,
|
|
unsigned long len);
|
|
|
|
extern bool userfaultfd_remove(struct vm_area_struct *vma,
|
|
unsigned long start,
|
|
unsigned long end);
|
|
|
|
extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
|
|
unsigned long start, unsigned long end,
|
|
struct list_head *uf);
|
|
extern void userfaultfd_unmap_complete(struct mm_struct *mm,
|
|
struct list_head *uf);
|
|
|
|
#else /* CONFIG_USERFAULTFD */
|
|
|
|
/* mm helpers */
|
|
static inline vm_fault_t handle_userfault(struct vm_fault *vmf,
|
|
unsigned long reason)
|
|
{
|
|
return VM_FAULT_SIGBUS;
|
|
}
|
|
|
|
static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
|
|
struct vm_userfaultfd_ctx vm_ctx)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
static inline bool userfaultfd_missing(struct vm_area_struct *vma)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static inline bool userfaultfd_wp(struct vm_area_struct *vma)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static inline bool userfaultfd_minor(struct vm_area_struct *vma)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma,
|
|
pte_t pte)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static inline bool userfaultfd_huge_pmd_wp(struct vm_area_struct *vma,
|
|
pmd_t pmd)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
|
|
static inline bool userfaultfd_armed(struct vm_area_struct *vma)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static inline int dup_userfaultfd(struct vm_area_struct *vma,
|
|
struct list_head *l)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void dup_userfaultfd_complete(struct list_head *l)
|
|
{
|
|
}
|
|
|
|
static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
|
|
struct vm_userfaultfd_ctx *ctx)
|
|
{
|
|
}
|
|
|
|
static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
|
|
unsigned long from,
|
|
unsigned long to,
|
|
unsigned long len)
|
|
{
|
|
}
|
|
|
|
static inline bool userfaultfd_remove(struct vm_area_struct *vma,
|
|
unsigned long start,
|
|
unsigned long end)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma,
|
|
unsigned long start, unsigned long end,
|
|
struct list_head *uf)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
|
|
struct list_head *uf)
|
|
{
|
|
}
|
|
|
|
static inline bool uffd_disable_fault_around(struct vm_area_struct *vma)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
#endif /* CONFIG_USERFAULTFD */
|
|
|
|
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.
|
|
*/
|
|
static inline bool pte_swp_uffd_wp_any(pte_t pte)
|
|
{
|
|
#ifdef CONFIG_PTE_MARKER_UFFD_WP
|
|
if (!is_swap_pte(pte))
|
|
return false;
|
|
|
|
if (pte_swp_uffd_wp(pte))
|
|
return true;
|
|
|
|
if (pte_marker_uffd_wp(pte))
|
|
return true;
|
|
#endif
|
|
return false;
|
|
}
|
|
|
|
#endif /* _LINUX_USERFAULTFD_K_H */
|