linux/mm/mprotect.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  mm/mprotect.c
 *
 *  (C) Copyright 1994 Linus Torvalds
 *  (C) Copyright 2002 Christoph Hellwig
 *
 *  Address space accounting code	<[email protected]>
 *  (C) Copyright 2002 Red Hat Inc, All Rights Reserved
 */

#include <linux/pagewalk.h>
#include <linux/hugetlb.h>
#include <linux/shm.h>
#include <linux/mman.h>
#include <linux/fs.h>
#include <linux/highmem.h>
#include <linux/security.h>
#include <linux/mempolicy.h>
#include <linux/personality.h>
#include <linux/syscalls.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/mmu_notifier.h>
#include <linux/migrate.h>
#include <linux/perf_event.h>
#include <linux/pkeys.h>
#include <linux/ksm.h>
#include <linux/uaccess.h>
#include <linux/mm_inline.h>
#include <linux/pgtable.h>
#include <linux/sched/sysctl.h>
#include <linux/userfaultfd_k.h>
#include <linux/memory-tiers.h>
#include <uapi/linux/mman.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/tlb.h>

#include "internal.h"

bool can_change_pte_writable(struct vm_area_struct *vma, unsigned long addr,
			     pte_t pte)
{ … }

static long change_pte_range(struct mmu_gather *tlb,
		struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr,
		unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{ … }

/*
 * Return true if we want to split THPs into PTE mappings in change
 * protection procedure, false otherwise.
 */
static inline bool
pgtable_split_needed(struct vm_area_struct *vma, unsigned long cp_flags)
{ … }

/*
 * Return true if we want to populate pgtables in change protection
 * procedure, false otherwise
 */
static inline bool
pgtable_populate_needed(struct vm_area_struct *vma, unsigned long cp_flags)
{ … }

/*
 * Populate the pgtable underneath for whatever reason if requested.
 * When {pte|pmd|...}_alloc() failed we treat it the same way as pgtable
 * allocation failures during page faults by kicking OOM and returning
 * error.
 */
#define change_pmd_prepare(vma, pmd, cp_flags) …

/*
 * This is the general pud/p4d/pgd version of change_pmd_prepare(). We need to
 * have separate change_pmd_prepare() because pte_alloc() returns 0 on success,
 * while {pmd|pud|p4d}_alloc() returns the valid pointer on success.
 */
#define change_prepare(vma, high, low, addr, cp_flags) …

static inline long change_pmd_range(struct mmu_gather *tlb,
		struct vm_area_struct *vma, pud_t *pud, unsigned long addr,
		unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{ … }

static inline long change_pud_range(struct mmu_gather *tlb,
		struct vm_area_struct *vma, p4d_t *p4d, unsigned long addr,
		unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{ … }

static inline long change_p4d_range(struct mmu_gather *tlb,
		struct vm_area_struct *vma, pgd_t *pgd, unsigned long addr,
		unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{ … }

static long change_protection_range(struct mmu_gather *tlb,
		struct vm_area_struct *vma, unsigned long addr,
		unsigned long end, pgprot_t newprot, unsigned long cp_flags)
{ … }

long change_protection(struct mmu_gather *tlb,
		       struct vm_area_struct *vma, unsigned long start,
		       unsigned long end, unsigned long cp_flags)
{ … }

static int prot_none_pte_entry(pte_t *pte, unsigned long addr,
			       unsigned long next, struct mm_walk *walk)
{ … }

static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask,
				   unsigned long addr, unsigned long next,
				   struct mm_walk *walk)
{ … }

static int prot_none_test(unsigned long addr, unsigned long next,
			  struct mm_walk *walk)
{ … }

static const struct mm_walk_ops prot_none_walk_ops = …;

int
mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,
	       struct vm_area_struct *vma, struct vm_area_struct **pprev,
	       unsigned long start, unsigned long end, unsigned long newflags)
{ … }

/*
 * pkey==-1 when doing a legacy mprotect()
 */
static int do_mprotect_pkey(unsigned long start, size_t len,
		unsigned long prot, int pkey)
{ … }

SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
		unsigned long, prot)
{ … }

#ifdef CONFIG_ARCH_HAS_PKEYS

SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
		unsigned long, prot, int, pkey)
{ … }

SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)
{ … }

SYSCALL_DEFINE1(pkey_free, int, pkey)
{ … }

#endif /* CONFIG_ARCH_HAS_PKEYS */