[linux-2.6-block.git] / mm / mprotect.c

/*
 *  mm/mprotect.c
 *
 *  (C) Copyright 1994 Linus Torvalds
 *  (C) Copyright 2002 Christoph Hellwig
 *
 *  Address space accounting code	<alan@lxorguk.ukuu.org.uk>
 *  (C) Copyright 2002 Red Hat Inc, All Rights Reserved
 */

#include <linux/mm.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 <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>

#ifndef pgprot_modify
static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
{
	return newprot;
}
#endif

static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
		unsigned long addr, unsigned long end, pgprot_t newprot,
		int dirty_accountable, int prot_numa, bool *ret_all_same_cpupid)
{
	struct mm_struct *mm = vma->vm_mm;
	pte_t *pte, oldpte;
	spinlock_t *ptl;
	unsigned long pages = 0;
	bool all_same_cpupid = true;
	int last_cpu = -1;
	int last_pid = -1;

	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
	arch_enter_lazy_mmu_mode();
	do {
		oldpte = *pte;
		if (pte_present(oldpte)) {
			pte_t ptent;
			bool updated = false;

			ptent = ptep_modify_prot_start(mm, addr, pte);
			if (!prot_numa) {
				ptent = pte_modify(ptent, newprot);
				updated = true;
			} else {
				struct page *page;

				page = vm_normal_page(vma, addr, oldpte);
				if (page) {
					int cpupid = page_cpupid_last(page);
					int this_cpu = cpupid_to_cpu(cpupid);
					int this_pid = cpupid_to_pid(cpupid);

					if (last_cpu == -1)
						last_cpu = this_cpu;
					if (last_pid == -1)
						last_pid = this_pid;
					if (last_cpu != this_cpu ||
					    last_pid != this_pid) {
						all_same_cpupid = false;
					}

					if (!pte_numa(oldpte)) {
						ptent = pte_mknuma(ptent);
						updated = true;
					}
				}
			}

			/*
			 * Avoid taking write faults for pages we know to be
			 * dirty.
			 */
			if (dirty_accountable && pte_dirty(ptent)) {
				ptent = pte_mkwrite(ptent);
				updated = true;
			}

			if (updated)
				pages++;
			ptep_modify_prot_commit(mm, addr, pte, ptent);
		} else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) {
			swp_entry_t entry = pte_to_swp_entry(oldpte);

			if (is_write_migration_entry(entry)) {
				/*
				 * A protection check is difficult so
				 * just be safe and disable write
				 */
				make_migration_entry_read(&entry);
				set_pte_at(mm, addr, pte,
					swp_entry_to_pte(entry));

				pages++;
			}
		}
	} while (pte++, addr += PAGE_SIZE, addr != end);
	arch_leave_lazy_mmu_mode();
	pte_unmap_unlock(pte - 1, ptl);

	*ret_all_same_cpupid = all_same_cpupid;
	return pages;
}

#ifdef CONFIG_NUMA_BALANCING
static inline void change_pmd_protnuma(struct mm_struct *mm, unsigned long addr,
				       pmd_t *pmd)
{
	spin_lock(&mm->page_table_lock);
	set_pmd_at(mm, addr & PMD_MASK, pmd, pmd_mknuma(*pmd));
	spin_unlock(&mm->page_table_lock);
}
#else
static inline void change_pmd_protnuma(struct mm_struct *mm, unsigned long addr,
				       pmd_t *pmd)
{
	BUG();
}
#endif /* CONFIG_NUMA_BALANCING */

static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
		pud_t *pud, unsigned long addr, unsigned long end,
		pgprot_t newprot, int dirty_accountable, int prot_numa)
{
	pmd_t *pmd;
	unsigned long next;
	unsigned long pages = 0;
	bool all_same_cpupid;

	pmd = pmd_offset(pud, addr);
	do {
		unsigned long this_pages;

		next = pmd_addr_end(addr, end);
		if (pmd_trans_huge(*pmd)) {
			if (next - addr != HPAGE_PMD_SIZE)
				split_huge_page_pmd(vma, addr, pmd);
			else {
				int nr_ptes = change_huge_pmd(vma, pmd, addr,
						newprot, prot_numa);

				if (nr_ptes) {
					if (nr_ptes == HPAGE_PMD_NR)
						pages++;

					continue;
				}
			}
			/* fall through */
		}
		if (pmd_none_or_clear_bad(pmd))
			continue;
		this_pages = change_pte_range(vma, pmd, addr, next, newprot,
				 dirty_accountable, prot_numa, &all_same_cpupid);
		pages += this_pages;

		/*
		 * If we are changing protections for NUMA hinting faults then
		 * set pmd_numa if the examined pages were all on the same
		 * node. This allows a regular PMD to be handled as one fault
		 * and effectively batches the taking of the PTL
		 */
		if (prot_numa && this_pages && all_same_cpupid)
			change_pmd_protnuma(vma->vm_mm, addr, pmd);
	} while (pmd++, addr = next, addr != end);

	return pages;
}

static inline unsigned long change_pud_range(struct vm_area_struct *vma,
		pgd_t *pgd, unsigned long addr, unsigned long end,
		pgprot_t newprot, int dirty_accountable, int prot_numa)
{
	pud_t *pud;
	unsigned long next;
	unsigned long pages = 0;

	pud = pud_offset(pgd, addr);
	do {
		next = pud_addr_end(addr, end);
		if (pud_none_or_clear_bad(pud))
			continue;
		pages += change_pmd_range(vma, pud, addr, next, newprot,
				 dirty_accountable, prot_numa);
	} while (pud++, addr = next, addr != end);

	return pages;
}

static unsigned long change_protection_range(struct vm_area_struct *vma,
		unsigned long addr, unsigned long end, pgprot_t newprot,
		int dirty_accountable, int prot_numa)
{
	struct mm_struct *mm = vma->vm_mm;
	pgd_t *pgd;
	unsigned long next;
	unsigned long start = addr;
	unsigned long pages = 0;

	BUG_ON(addr >= end);
	pgd = pgd_offset(mm, addr);
	flush_cache_range(vma, addr, end);
	do {
		next = pgd_addr_end(addr, end);
		if (pgd_none_or_clear_bad(pgd))
			continue;
		pages += change_pud_range(vma, pgd, addr, next, newprot,
				 dirty_accountable, prot_numa);
	} while (pgd++, addr = next, addr != end);

	/* Only flush the TLB if we actually modified any entries: */
	if (pages)
		flush_tlb_range(vma, start, end);

	return pages;
}

unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
		       unsigned long end, pgprot_t newprot,
		       int dirty_accountable, int prot_numa)
{
	struct mm_struct *mm = vma->vm_mm;
	unsigned long pages;

	mmu_notifier_invalidate_range_start(mm, start, end);
	if (is_vm_hugetlb_page(vma))
		pages = hugetlb_change_protection(vma, start, end, newprot);
	else
		pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa);
	mmu_notifier_invalidate_range_end(mm, start, end);

	return pages;
}

int
mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
	unsigned long start, unsigned long end, unsigned long newflags)
{
	struct mm_struct *mm = vma->vm_mm;
	unsigned long oldflags = vma->vm_flags;
	long nrpages = (end - start) >> PAGE_SHIFT;
	unsigned long charged = 0;
	pgoff_t pgoff;
	int error;
	int dirty_accountable = 0;

	if (newflags == oldflags) {
		*pprev = vma;
		return 0;
	}

	/*
	 * If we make a private mapping writable we increase our commit;
	 * but (without finer accounting) cannot reduce our commit if we
	 * make it unwritable again. hugetlb mapping were accounted for
	 * even if read-only so there is no need to account for them here
	 */
	if (newflags & VM_WRITE) {
		if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB|
						VM_SHARED|VM_NORESERVE))) {
			charged = nrpages;
			if (security_vm_enough_memory_mm(mm, charged))
				return -ENOMEM;
			newflags |= VM_ACCOUNT;
		}
	}

	/*
	 * First try to merge with previous and/or next vma.
	 */
	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
	*pprev = vma_merge(mm, *pprev, start, end, newflags,
			vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
	if (*pprev) {
		vma = *pprev;
		goto success;
	}

	*pprev = vma;

	if (start != vma->vm_start) {
		error = split_vma(mm, vma, start, 1);
		if (error)
			goto fail;
	}

	if (end != vma->vm_end) {
		error = split_vma(mm, vma, end, 0);
		if (error)
			goto fail;
	}

success:
	/*
	 * vm_flags and vm_page_prot are protected by the mmap_sem
	 * held in write mode.
	 */
	vma->vm_flags = newflags;
	vma->vm_page_prot = pgprot_modify(vma->vm_page_prot,
					  vm_get_page_prot(newflags));

	if (vma_wants_writenotify(vma)) {
		vma->vm_page_prot = vm_get_page_prot(newflags & ~VM_SHARED);
		dirty_accountable = 1;
	}

	change_protection(vma, start, end, vma->vm_page_prot,
			  dirty_accountable, 0);

	vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
	vm_stat_account(mm, newflags, vma->vm_file, nrpages);
	perf_event_mmap(vma);
	return 0;

fail:
	vm_unacct_memory(charged);
	return error;
}

SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
		unsigned long, prot)
{
	unsigned long vm_flags, nstart, end, tmp, reqprot;
	struct vm_area_struct *vma, *prev;
	int error = -EINVAL;
	const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
	prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
	if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
		return -EINVAL;

	if (start & ~PAGE_MASK)
		return -EINVAL;
	if (!len)
		return 0;
	len = PAGE_ALIGN(len);
	end = start + len;
	if (end <= start)
		return -ENOMEM;
	if (!arch_validate_prot(prot))
		return -EINVAL;

	reqprot = prot;
	/*
	 * Does the application expect PROT_READ to imply PROT_EXEC:
	 */
	if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
		prot |= PROT_EXEC;

	vm_flags = calc_vm_prot_bits(prot);

	down_write(&current->mm->mmap_sem);

	vma = find_vma(current->mm, start);
	error = -ENOMEM;
	if (!vma)
		goto out;
	prev = vma->vm_prev;
	if (unlikely(grows & PROT_GROWSDOWN)) {
		if (vma->vm_start >= end)
			goto out;
		start = vma->vm_start;
		error = -EINVAL;
		if (!(vma->vm_flags & VM_GROWSDOWN))
			goto out;
	} else {
		if (vma->vm_start > start)
			goto out;
		if (unlikely(grows & PROT_GROWSUP)) {
			end = vma->vm_end;
			error = -EINVAL;
			if (!(vma->vm_flags & VM_GROWSUP))
				goto out;
		}
	}
	if (start > vma->vm_start)
		prev = vma;

	for (nstart = start ; ; ) {
		unsigned long newflags;

		/* Here we know that vma->vm_start <= nstart < vma->vm_end. */

		newflags = vm_flags;
		newflags |= (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));

		/* newflags >> 4 shift VM_MAY% in place of VM_% */
		if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
			error = -EACCES;
			goto out;
		}

		error = security_file_mprotect(vma, reqprot, prot);
		if (error)
			goto out;

		tmp = vma->vm_end;
		if (tmp > end)
			tmp = end;
		error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
		if (error)
			goto out;
		nstart = tmp;

		if (nstart < prev->vm_end)
			nstart = prev->vm_end;
		if (nstart >= end)
			goto out;

		vma = prev->vm_next;
		if (!vma || vma->vm_start != nstart) {
			error = -ENOMEM;
			goto out;
		}
	}
out:
	up_write(&current->mm->mmap_sem);
	return error;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* mm/mprotect.c
	3	*
	4	* (C) Copyright 1994 Linus Torvalds
	5	* (C) Copyright 2002 Christoph Hellwig
	6	*
046c6884	7	* Address space accounting code <alan@lxorguk.ukuu.org.uk>
1da177e4 LT	8	* (C) Copyright 2002 Red Hat Inc, All Rights Reserved
	9	*/
	10
	11	#include <linux/mm.h>
	12	#include <linux/hugetlb.h>
1da177e4 LT	13	#include <linux/shm.h>
	14	#include <linux/mman.h>
	15	#include <linux/fs.h>
	16	#include <linux/highmem.h>
	17	#include <linux/security.h>
	18	#include <linux/mempolicy.h>
	19	#include <linux/personality.h>
	20	#include <linux/syscalls.h>
0697212a CL	21	#include <linux/swap.h>
0697212a CL	22	#include <linux/swapops.h>
cddb8a5c	23	#include <linux/mmu_notifier.h>
64cdd548	24	#include <linux/migrate.h>
cdd6c482	25	#include <linux/perf_event.h>
1da177e4 LT	26	#include <asm/uaccess.h>
	27	#include <asm/pgtable.h>
	28	#include <asm/cacheflush.h>
	29	#include <asm/tlbflush.h>
	30
1c12c4cf VP	31	#ifndef pgprot_modify
	32	static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
	33	{
	34	return newprot;
	35	}
	36	#endif
	37
4b10e7d5	38	static unsigned long change_pte_range(struct vm_area_struct vma, pmd_t pmd,
c1e6098b	39	unsigned long addr, unsigned long end, pgprot_t newprot,
90572890	40	int dirty_accountable, int prot_numa, bool *ret_all_same_cpupid)
1da177e4	41	{
4b10e7d5	42	struct mm_struct *mm = vma->vm_mm;
0697212a	43	pte_t *pte, oldpte;
705e87c0	44	spinlock_t *ptl;
7da4d641	45	unsigned long pages = 0;
90572890 PZ	46	bool all_same_cpupid = true;
90572890 PZ	47	int last_cpu = -1;
b795854b	48	int last_pid = -1;
1da177e4	49
705e87c0	50	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
6606c3e0	51	arch_enter_lazy_mmu_mode();
1da177e4	52	do {
0697212a CL	53	oldpte = *pte;
0697212a CL	54	if (pte_present(oldpte)) {
1da177e4	55	pte_t ptent;
4b10e7d5	56	bool updated = false;
1da177e4	57
1ea0704e	58	ptent = ptep_modify_prot_start(mm, addr, pte);
4b10e7d5 MG	59	if (!prot_numa) {
	60	ptent = pte_modify(ptent, newprot);
	61	updated = true;
	62	} else {
	63	struct page *page;
	64
	65	page = vm_normal_page(vma, addr, oldpte);
	66	if (page) {
90572890 PZ	67	int cpupid = page_cpupid_last(page);
	68	int this_cpu = cpupid_to_cpu(cpupid);
	69	int this_pid = cpupid_to_pid(cpupid);
b795854b	70
90572890 PZ	71	if (last_cpu == -1)
90572890 PZ	72	last_cpu = this_cpu;
b795854b MG	73	if (last_pid == -1)
b795854b MG	74	last_pid = this_pid;
90572890	75	if (last_cpu != this_cpu \|\|
b795854b	76	last_pid != this_pid) {
90572890	77	all_same_cpupid = false;
b795854b	78	}
9532fec1	79
1bc115d8	80	if (!pte_numa(oldpte)) {
4b10e7d5 MG	81	ptent = pte_mknuma(ptent);
	82	updated = true;
	83	}
	84	}
	85	}
1ea0704e	86
c1e6098b PZ	87	/*
	88	* Avoid taking write faults for pages we know to be
	89	* dirty.
	90	*/
4b10e7d5	91	if (dirty_accountable && pte_dirty(ptent)) {
c1e6098b	92	ptent = pte_mkwrite(ptent);
4b10e7d5 MG	93	updated = true;
4b10e7d5 MG	94	}
1ea0704e	95
4b10e7d5 MG	96	if (updated)
4b10e7d5 MG	97	pages++;
1ea0704e	98	ptep_modify_prot_commit(mm, addr, pte, ptent);
ce1744f4	99	} else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) {
0697212a CL	100	swp_entry_t entry = pte_to_swp_entry(oldpte);
	101
	102	if (is_write_migration_entry(entry)) {
	103	/*
	104	* A protection check is difficult so
	105	* just be safe and disable write
	106	*/
	107	make_migration_entry_read(&entry);
	108	set_pte_at(mm, addr, pte,
	109	swp_entry_to_pte(entry));
e920e14c MG	110
e920e14c MG	111	pages++;
0697212a	112	}
1da177e4 LT	113	}
1da177e4 LT	114	} while (pte++, addr += PAGE_SIZE, addr != end);
6606c3e0	115	arch_leave_lazy_mmu_mode();
705e87c0	116	pte_unmap_unlock(pte - 1, ptl);
7da4d641	117
90572890	118	*ret_all_same_cpupid = all_same_cpupid;
7da4d641	119	return pages;
1da177e4 LT	120	}
1da177e4 LT	121
4b10e7d5 MG	122	#ifdef CONFIG_NUMA_BALANCING
4b10e7d5 MG	123	static inline void change_pmd_protnuma(struct mm_struct *mm, unsigned long addr,
7d12efae	124	pmd_t *pmd)
4b10e7d5 MG	125	{
	126	spin_lock(&mm->page_table_lock);
	127	set_pmd_at(mm, addr & PMD_MASK, pmd, pmd_mknuma(*pmd));
	128	spin_unlock(&mm->page_table_lock);
	129	}
	130	#else
	131	static inline void change_pmd_protnuma(struct mm_struct *mm, unsigned long addr,
7d12efae	132	pmd_t *pmd)
4b10e7d5 MG	133	{
4b10e7d5 MG	134	BUG();
1da177e4	135	}
4b10e7d5	136	#endif /* CONFIG_NUMA_BALANCING */
1da177e4	137
7d12efae AM	138	static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
	139	pud_t *pud, unsigned long addr, unsigned long end,
	140	pgprot_t newprot, int dirty_accountable, int prot_numa)
1da177e4 LT	141	{
	142	pmd_t *pmd;
	143	unsigned long next;
7da4d641	144	unsigned long pages = 0;
90572890	145	bool all_same_cpupid;
1da177e4 LT	146
	147	pmd = pmd_offset(pud, addr);
	148	do {
25cbbef1 MG	149	unsigned long this_pages;
25cbbef1 MG	150
1da177e4	151	next = pmd_addr_end(addr, end);
cd7548ab JW	152	if (pmd_trans_huge(*pmd)) {
cd7548ab JW	153	if (next - addr != HPAGE_PMD_SIZE)
e180377f	154	split_huge_page_pmd(vma, addr, pmd);
f123d74a MG	155	else {
	156	int nr_ptes = change_huge_pmd(vma, pmd, addr,
	157	newprot, prot_numa);
	158
	159	if (nr_ptes) {
	160	if (nr_ptes == HPAGE_PMD_NR)
	161	pages++;
	162
	163	continue;
	164	}
7da4d641	165	}
cd7548ab JW	166	/* fall through */
cd7548ab JW	167	}
1da177e4 LT	168	if (pmd_none_or_clear_bad(pmd))
1da177e4 LT	169	continue;
25cbbef1	170	this_pages = change_pte_range(vma, pmd, addr, next, newprot,
90572890	171	dirty_accountable, prot_numa, &all_same_cpupid);
25cbbef1	172	pages += this_pages;
4b10e7d5	173
9532fec1 MG	174	/*
	175	* If we are changing protections for NUMA hinting faults then
	176	* set pmd_numa if the examined pages were all on the same
	177	* node. This allows a regular PMD to be handled as one fault
	178	* and effectively batches the taking of the PTL
	179	*/
90572890	180	if (prot_numa && this_pages && all_same_cpupid)
4b10e7d5	181	change_pmd_protnuma(vma->vm_mm, addr, pmd);
1da177e4	182	} while (pmd++, addr = next, addr != end);
7da4d641 PZ	183
7da4d641 PZ	184	return pages;
1da177e4 LT	185	}
1da177e4 LT	186
7d12efae AM	187	static inline unsigned long change_pud_range(struct vm_area_struct *vma,
	188	pgd_t *pgd, unsigned long addr, unsigned long end,
	189	pgprot_t newprot, int dirty_accountable, int prot_numa)
1da177e4 LT	190	{
	191	pud_t *pud;
	192	unsigned long next;
7da4d641	193	unsigned long pages = 0;
1da177e4 LT	194
	195	pud = pud_offset(pgd, addr);
	196	do {
	197	next = pud_addr_end(addr, end);
	198	if (pud_none_or_clear_bad(pud))
	199	continue;
7da4d641	200	pages += change_pmd_range(vma, pud, addr, next, newprot,
4b10e7d5	201	dirty_accountable, prot_numa);
1da177e4	202	} while (pud++, addr = next, addr != end);
7da4d641 PZ	203
7da4d641 PZ	204	return pages;
1da177e4 LT	205	}
1da177e4 LT	206
7da4d641	207	static unsigned long change_protection_range(struct vm_area_struct *vma,
c1e6098b	208	unsigned long addr, unsigned long end, pgprot_t newprot,
4b10e7d5	209	int dirty_accountable, int prot_numa)
1da177e4 LT	210	{
	211	struct mm_struct *mm = vma->vm_mm;
	212	pgd_t *pgd;
	213	unsigned long next;
	214	unsigned long start = addr;
7da4d641	215	unsigned long pages = 0;
1da177e4 LT	216
	217	BUG_ON(addr >= end);
	218	pgd = pgd_offset(mm, addr);
	219	flush_cache_range(vma, addr, end);
1da177e4 LT	220	do {
	221	next = pgd_addr_end(addr, end);
	222	if (pgd_none_or_clear_bad(pgd))
	223	continue;
7da4d641	224	pages += change_pud_range(vma, pgd, addr, next, newprot,
4b10e7d5	225	dirty_accountable, prot_numa);
1da177e4	226	} while (pgd++, addr = next, addr != end);
7da4d641	227
1233d588 IM	228	/* Only flush the TLB if we actually modified any entries: */
	229	if (pages)
	230	flush_tlb_range(vma, start, end);
7da4d641 PZ	231
	232	return pages;
	233	}
	234
	235	unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
	236	unsigned long end, pgprot_t newprot,
4b10e7d5	237	int dirty_accountable, int prot_numa)
7da4d641 PZ	238	{
	239	struct mm_struct *mm = vma->vm_mm;
	240	unsigned long pages;
	241
	242	mmu_notifier_invalidate_range_start(mm, start, end);
	243	if (is_vm_hugetlb_page(vma))
	244	pages = hugetlb_change_protection(vma, start, end, newprot);
	245	else
4b10e7d5	246	pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa);
7da4d641 PZ	247	mmu_notifier_invalidate_range_end(mm, start, end);
	248
	249	return pages;
1da177e4 LT	250	}
1da177e4 LT	251
b6a2fea3	252	int
1da177e4 LT	253	mprotect_fixup(struct vm_area_struct vma, struct vm_area_struct *pprev,
	254	unsigned long start, unsigned long end, unsigned long newflags)
	255	{
	256	struct mm_struct *mm = vma->vm_mm;
	257	unsigned long oldflags = vma->vm_flags;
	258	long nrpages = (end - start) >> PAGE_SHIFT;
	259	unsigned long charged = 0;
1da177e4 LT	260	pgoff_t pgoff;
1da177e4 LT	261	int error;
c1e6098b	262	int dirty_accountable = 0;
1da177e4 LT	263
	264	if (newflags == oldflags) {
	265	*pprev = vma;
	266	return 0;
	267	}
	268
	269	/*
	270	* If we make a private mapping writable we increase our commit;
	271	* but (without finer accounting) cannot reduce our commit if we
5a6fe125 MG	272	* make it unwritable again. hugetlb mapping were accounted for
5a6fe125 MG	273	* even if read-only so there is no need to account for them here
1da177e4 LT	274	*/
1da177e4 LT	275	if (newflags & VM_WRITE) {
5a6fe125	276	if (!(oldflags & (VM_ACCOUNT\|VM_WRITE\|VM_HUGETLB\|
cdfd4325	277	VM_SHARED\|VM_NORESERVE))) {
1da177e4	278	charged = nrpages;
191c5424	279	if (security_vm_enough_memory_mm(mm, charged))
1da177e4 LT	280	return -ENOMEM;
	281	newflags \|= VM_ACCOUNT;
	282	}
	283	}
	284
1da177e4 LT	285	/*
	286	* First try to merge with previous and/or next vma.
	287	*/
	288	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
	289	pprev = vma_merge(mm, pprev, start, end, newflags,
	290	vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
	291	if (*pprev) {
	292	vma = *pprev;
	293	goto success;
	294	}
	295
	296	*pprev = vma;
	297
	298	if (start != vma->vm_start) {
	299	error = split_vma(mm, vma, start, 1);
	300	if (error)
	301	goto fail;
	302	}
	303
	304	if (end != vma->vm_end) {
	305	error = split_vma(mm, vma, end, 0);
	306	if (error)
	307	goto fail;
	308	}
	309
	310	success:
	311	/*
	312	* vm_flags and vm_page_prot are protected by the mmap_sem
	313	* held in write mode.
	314	*/
	315	vma->vm_flags = newflags;
1c12c4cf VP	316	vma->vm_page_prot = pgprot_modify(vma->vm_page_prot,
	317	vm_get_page_prot(newflags));
	318
c1e6098b	319	if (vma_wants_writenotify(vma)) {
1ddd439e	320	vma->vm_page_prot = vm_get_page_prot(newflags & ~VM_SHARED);
c1e6098b PZ	321	dirty_accountable = 1;
c1e6098b PZ	322	}
d08b3851	323
7d12efae AM	324	change_protection(vma, start, end, vma->vm_page_prot,
7d12efae AM	325	dirty_accountable, 0);
7da4d641	326
ab50b8ed HD	327	vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
ab50b8ed HD	328	vm_stat_account(mm, newflags, vma->vm_file, nrpages);
63bfd738	329	perf_event_mmap(vma);
1da177e4 LT	330	return 0;
	331
	332	fail:
	333	vm_unacct_memory(charged);
	334	return error;
	335	}
	336
6a6160a7 HC	337	SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
6a6160a7 HC	338	unsigned long, prot)
1da177e4 LT	339	{
	340	unsigned long vm_flags, nstart, end, tmp, reqprot;
	341	struct vm_area_struct vma, prev;
	342	int error = -EINVAL;
	343	const int grows = prot & (PROT_GROWSDOWN\|PROT_GROWSUP);
	344	prot &= ~(PROT_GROWSDOWN\|PROT_GROWSUP);
	345	if (grows == (PROT_GROWSDOWN\|PROT_GROWSUP)) /* can't be both */
	346	return -EINVAL;
	347
	348	if (start & ~PAGE_MASK)
	349	return -EINVAL;
	350	if (!len)
	351	return 0;
	352	len = PAGE_ALIGN(len);
	353	end = start + len;
	354	if (end <= start)
	355	return -ENOMEM;
b845f313	356	if (!arch_validate_prot(prot))
1da177e4 LT	357	return -EINVAL;
	358
	359	reqprot = prot;
	360	/*
	361	* Does the application expect PROT_READ to imply PROT_EXEC:
	362	*/
b344e05c	363	if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
1da177e4 LT	364	prot \|= PROT_EXEC;
	365
	366	vm_flags = calc_vm_prot_bits(prot);
	367
	368	down_write(&current->mm->mmap_sem);
	369
097d5910	370	vma = find_vma(current->mm, start);
1da177e4 LT	371	error = -ENOMEM;
	372	if (!vma)
	373	goto out;
097d5910	374	prev = vma->vm_prev;
1da177e4 LT	375	if (unlikely(grows & PROT_GROWSDOWN)) {
	376	if (vma->vm_start >= end)
	377	goto out;
	378	start = vma->vm_start;
	379	error = -EINVAL;
	380	if (!(vma->vm_flags & VM_GROWSDOWN))
	381	goto out;
7d12efae	382	} else {
1da177e4 LT	383	if (vma->vm_start > start)
	384	goto out;
	385	if (unlikely(grows & PROT_GROWSUP)) {
	386	end = vma->vm_end;
	387	error = -EINVAL;
	388	if (!(vma->vm_flags & VM_GROWSUP))
	389	goto out;
	390	}
	391	}
	392	if (start > vma->vm_start)
	393	prev = vma;
	394
	395	for (nstart = start ; ; ) {
	396	unsigned long newflags;
	397
7d12efae	398	/* Here we know that vma->vm_start <= nstart < vma->vm_end. */
1da177e4	399
7d12efae AM	400	newflags = vm_flags;
7d12efae AM	401	newflags \|= (vma->vm_flags & ~(VM_READ \| VM_WRITE \| VM_EXEC));
1da177e4	402
7e2cff42 PBG	403	/* newflags >> 4 shift VM_MAY% in place of VM_% */
7e2cff42 PBG	404	if ((newflags & ~(newflags >> 4)) & (VM_READ \| VM_WRITE \| VM_EXEC)) {
1da177e4 LT	405	error = -EACCES;
	406	goto out;
	407	}
	408
	409	error = security_file_mprotect(vma, reqprot, prot);
	410	if (error)
	411	goto out;
	412
	413	tmp = vma->vm_end;
	414	if (tmp > end)
	415	tmp = end;
	416	error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
	417	if (error)
	418	goto out;
	419	nstart = tmp;
	420
	421	if (nstart < prev->vm_end)
	422	nstart = prev->vm_end;
	423	if (nstart >= end)
	424	goto out;
	425
	426	vma = prev->vm_next;
	427	if (!vma \|\| vma->vm_start != nstart) {
	428	error = -ENOMEM;
	429	goto out;
	430	}
	431	}
	432	out:
	433	up_write(&current->mm->mmap_sem);
	434	return error;
	435	}