mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-24 21:24:00 +08:00
4fd39c23fe
These duplicate includes have been found with scripts/checkincludes.pl but they have been removed manually to avoid removing false positives. Link: http://lkml.kernel.org/r/1512580957-6071-1-git-send-email-pravin.shedge4linux@gmail.com Signed-off-by: Pravin Shedge <pravin.shedge4linux@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
576 lines
15 KiB
C
576 lines
15 KiB
C
/*
|
|
* mm/userfaultfd.c
|
|
*
|
|
* Copyright (C) 2015 Red Hat, Inc.
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2. See
|
|
* the COPYING file in the top-level directory.
|
|
*/
|
|
|
|
#include <linux/mm.h>
|
|
#include <linux/sched/signal.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/rmap.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/swapops.h>
|
|
#include <linux/userfaultfd_k.h>
|
|
#include <linux/mmu_notifier.h>
|
|
#include <linux/hugetlb.h>
|
|
#include <linux/shmem_fs.h>
|
|
#include <asm/tlbflush.h>
|
|
#include "internal.h"
|
|
|
|
static int mcopy_atomic_pte(struct mm_struct *dst_mm,
|
|
pmd_t *dst_pmd,
|
|
struct vm_area_struct *dst_vma,
|
|
unsigned long dst_addr,
|
|
unsigned long src_addr,
|
|
struct page **pagep)
|
|
{
|
|
struct mem_cgroup *memcg;
|
|
pte_t _dst_pte, *dst_pte;
|
|
spinlock_t *ptl;
|
|
void *page_kaddr;
|
|
int ret;
|
|
struct page *page;
|
|
|
|
if (!*pagep) {
|
|
ret = -ENOMEM;
|
|
page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, dst_vma, dst_addr);
|
|
if (!page)
|
|
goto out;
|
|
|
|
page_kaddr = kmap_atomic(page);
|
|
ret = copy_from_user(page_kaddr,
|
|
(const void __user *) src_addr,
|
|
PAGE_SIZE);
|
|
kunmap_atomic(page_kaddr);
|
|
|
|
/* fallback to copy_from_user outside mmap_sem */
|
|
if (unlikely(ret)) {
|
|
ret = -EFAULT;
|
|
*pagep = page;
|
|
/* don't free the page */
|
|
goto out;
|
|
}
|
|
} else {
|
|
page = *pagep;
|
|
*pagep = NULL;
|
|
}
|
|
|
|
/*
|
|
* The memory barrier inside __SetPageUptodate makes sure that
|
|
* preceeding stores to the page contents become visible before
|
|
* the set_pte_at() write.
|
|
*/
|
|
__SetPageUptodate(page);
|
|
|
|
ret = -ENOMEM;
|
|
if (mem_cgroup_try_charge(page, dst_mm, GFP_KERNEL, &memcg, false))
|
|
goto out_release;
|
|
|
|
_dst_pte = mk_pte(page, dst_vma->vm_page_prot);
|
|
if (dst_vma->vm_flags & VM_WRITE)
|
|
_dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte));
|
|
|
|
ret = -EEXIST;
|
|
dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
|
|
if (!pte_none(*dst_pte))
|
|
goto out_release_uncharge_unlock;
|
|
|
|
inc_mm_counter(dst_mm, MM_ANONPAGES);
|
|
page_add_new_anon_rmap(page, dst_vma, dst_addr, false);
|
|
mem_cgroup_commit_charge(page, memcg, false, false);
|
|
lru_cache_add_active_or_unevictable(page, dst_vma);
|
|
|
|
set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
|
|
|
|
/* No need to invalidate - it was non-present before */
|
|
update_mmu_cache(dst_vma, dst_addr, dst_pte);
|
|
|
|
pte_unmap_unlock(dst_pte, ptl);
|
|
ret = 0;
|
|
out:
|
|
return ret;
|
|
out_release_uncharge_unlock:
|
|
pte_unmap_unlock(dst_pte, ptl);
|
|
mem_cgroup_cancel_charge(page, memcg, false);
|
|
out_release:
|
|
put_page(page);
|
|
goto out;
|
|
}
|
|
|
|
static int mfill_zeropage_pte(struct mm_struct *dst_mm,
|
|
pmd_t *dst_pmd,
|
|
struct vm_area_struct *dst_vma,
|
|
unsigned long dst_addr)
|
|
{
|
|
pte_t _dst_pte, *dst_pte;
|
|
spinlock_t *ptl;
|
|
int ret;
|
|
|
|
_dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr),
|
|
dst_vma->vm_page_prot));
|
|
ret = -EEXIST;
|
|
dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
|
|
if (!pte_none(*dst_pte))
|
|
goto out_unlock;
|
|
set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
|
|
/* No need to invalidate - it was non-present before */
|
|
update_mmu_cache(dst_vma, dst_addr, dst_pte);
|
|
ret = 0;
|
|
out_unlock:
|
|
pte_unmap_unlock(dst_pte, ptl);
|
|
return ret;
|
|
}
|
|
|
|
static pmd_t *mm_alloc_pmd(struct mm_struct *mm, unsigned long address)
|
|
{
|
|
pgd_t *pgd;
|
|
p4d_t *p4d;
|
|
pud_t *pud;
|
|
|
|
pgd = pgd_offset(mm, address);
|
|
p4d = p4d_alloc(mm, pgd, address);
|
|
if (!p4d)
|
|
return NULL;
|
|
pud = pud_alloc(mm, p4d, address);
|
|
if (!pud)
|
|
return NULL;
|
|
/*
|
|
* Note that we didn't run this because the pmd was
|
|
* missing, the *pmd may be already established and in
|
|
* turn it may also be a trans_huge_pmd.
|
|
*/
|
|
return pmd_alloc(mm, pud, address);
|
|
}
|
|
|
|
#ifdef CONFIG_HUGETLB_PAGE
|
|
/*
|
|
* __mcopy_atomic processing for HUGETLB vmas. Note that this routine is
|
|
* called with mmap_sem held, it will release mmap_sem before returning.
|
|
*/
|
|
static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
|
|
struct vm_area_struct *dst_vma,
|
|
unsigned long dst_start,
|
|
unsigned long src_start,
|
|
unsigned long len,
|
|
bool zeropage)
|
|
{
|
|
int vm_alloc_shared = dst_vma->vm_flags & VM_SHARED;
|
|
int vm_shared = dst_vma->vm_flags & VM_SHARED;
|
|
ssize_t err;
|
|
pte_t *dst_pte;
|
|
unsigned long src_addr, dst_addr;
|
|
long copied;
|
|
struct page *page;
|
|
struct hstate *h;
|
|
unsigned long vma_hpagesize;
|
|
pgoff_t idx;
|
|
u32 hash;
|
|
struct address_space *mapping;
|
|
|
|
/*
|
|
* There is no default zero huge page for all huge page sizes as
|
|
* supported by hugetlb. A PMD_SIZE huge pages may exist as used
|
|
* by THP. Since we can not reliably insert a zero page, this
|
|
* feature is not supported.
|
|
*/
|
|
if (zeropage) {
|
|
up_read(&dst_mm->mmap_sem);
|
|
return -EINVAL;
|
|
}
|
|
|
|
src_addr = src_start;
|
|
dst_addr = dst_start;
|
|
copied = 0;
|
|
page = NULL;
|
|
vma_hpagesize = vma_kernel_pagesize(dst_vma);
|
|
|
|
/*
|
|
* Validate alignment based on huge page size
|
|
*/
|
|
err = -EINVAL;
|
|
if (dst_start & (vma_hpagesize - 1) || len & (vma_hpagesize - 1))
|
|
goto out_unlock;
|
|
|
|
retry:
|
|
/*
|
|
* On routine entry dst_vma is set. If we had to drop mmap_sem and
|
|
* retry, dst_vma will be set to NULL and we must lookup again.
|
|
*/
|
|
if (!dst_vma) {
|
|
err = -ENOENT;
|
|
dst_vma = find_vma(dst_mm, dst_start);
|
|
if (!dst_vma || !is_vm_hugetlb_page(dst_vma))
|
|
goto out_unlock;
|
|
/*
|
|
* Only allow __mcopy_atomic_hugetlb on userfaultfd
|
|
* registered ranges.
|
|
*/
|
|
if (!dst_vma->vm_userfaultfd_ctx.ctx)
|
|
goto out_unlock;
|
|
|
|
if (dst_start < dst_vma->vm_start ||
|
|
dst_start + len > dst_vma->vm_end)
|
|
goto out_unlock;
|
|
|
|
err = -EINVAL;
|
|
if (vma_hpagesize != vma_kernel_pagesize(dst_vma))
|
|
goto out_unlock;
|
|
|
|
vm_shared = dst_vma->vm_flags & VM_SHARED;
|
|
}
|
|
|
|
if (WARN_ON(dst_addr & (vma_hpagesize - 1) ||
|
|
(len - copied) & (vma_hpagesize - 1)))
|
|
goto out_unlock;
|
|
|
|
/*
|
|
* If not shared, ensure the dst_vma has a anon_vma.
|
|
*/
|
|
err = -ENOMEM;
|
|
if (!vm_shared) {
|
|
if (unlikely(anon_vma_prepare(dst_vma)))
|
|
goto out_unlock;
|
|
}
|
|
|
|
h = hstate_vma(dst_vma);
|
|
|
|
while (src_addr < src_start + len) {
|
|
pte_t dst_pteval;
|
|
|
|
BUG_ON(dst_addr >= dst_start + len);
|
|
VM_BUG_ON(dst_addr & ~huge_page_mask(h));
|
|
|
|
/*
|
|
* Serialize via hugetlb_fault_mutex
|
|
*/
|
|
idx = linear_page_index(dst_vma, dst_addr);
|
|
mapping = dst_vma->vm_file->f_mapping;
|
|
hash = hugetlb_fault_mutex_hash(h, dst_mm, dst_vma, mapping,
|
|
idx, dst_addr);
|
|
mutex_lock(&hugetlb_fault_mutex_table[hash]);
|
|
|
|
err = -ENOMEM;
|
|
dst_pte = huge_pte_alloc(dst_mm, dst_addr, huge_page_size(h));
|
|
if (!dst_pte) {
|
|
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
|
|
goto out_unlock;
|
|
}
|
|
|
|
err = -EEXIST;
|
|
dst_pteval = huge_ptep_get(dst_pte);
|
|
if (!huge_pte_none(dst_pteval)) {
|
|
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
|
|
goto out_unlock;
|
|
}
|
|
|
|
err = hugetlb_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma,
|
|
dst_addr, src_addr, &page);
|
|
|
|
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
|
|
vm_alloc_shared = vm_shared;
|
|
|
|
cond_resched();
|
|
|
|
if (unlikely(err == -EFAULT)) {
|
|
up_read(&dst_mm->mmap_sem);
|
|
BUG_ON(!page);
|
|
|
|
err = copy_huge_page_from_user(page,
|
|
(const void __user *)src_addr,
|
|
pages_per_huge_page(h), true);
|
|
if (unlikely(err)) {
|
|
err = -EFAULT;
|
|
goto out;
|
|
}
|
|
down_read(&dst_mm->mmap_sem);
|
|
|
|
dst_vma = NULL;
|
|
goto retry;
|
|
} else
|
|
BUG_ON(page);
|
|
|
|
if (!err) {
|
|
dst_addr += vma_hpagesize;
|
|
src_addr += vma_hpagesize;
|
|
copied += vma_hpagesize;
|
|
|
|
if (fatal_signal_pending(current))
|
|
err = -EINTR;
|
|
}
|
|
if (err)
|
|
break;
|
|
}
|
|
|
|
out_unlock:
|
|
up_read(&dst_mm->mmap_sem);
|
|
out:
|
|
if (page) {
|
|
/*
|
|
* We encountered an error and are about to free a newly
|
|
* allocated huge page.
|
|
*
|
|
* Reservation handling is very subtle, and is different for
|
|
* private and shared mappings. See the routine
|
|
* restore_reserve_on_error for details. Unfortunately, we
|
|
* can not call restore_reserve_on_error now as it would
|
|
* require holding mmap_sem.
|
|
*
|
|
* If a reservation for the page existed in the reservation
|
|
* map of a private mapping, the map was modified to indicate
|
|
* the reservation was consumed when the page was allocated.
|
|
* We clear the PagePrivate flag now so that the global
|
|
* reserve count will not be incremented in free_huge_page.
|
|
* The reservation map will still indicate the reservation
|
|
* was consumed and possibly prevent later page allocation.
|
|
* This is better than leaking a global reservation. If no
|
|
* reservation existed, it is still safe to clear PagePrivate
|
|
* as no adjustments to reservation counts were made during
|
|
* allocation.
|
|
*
|
|
* The reservation map for shared mappings indicates which
|
|
* pages have reservations. When a huge page is allocated
|
|
* for an address with a reservation, no change is made to
|
|
* the reserve map. In this case PagePrivate will be set
|
|
* to indicate that the global reservation count should be
|
|
* incremented when the page is freed. This is the desired
|
|
* behavior. However, when a huge page is allocated for an
|
|
* address without a reservation a reservation entry is added
|
|
* to the reservation map, and PagePrivate will not be set.
|
|
* When the page is freed, the global reserve count will NOT
|
|
* be incremented and it will appear as though we have leaked
|
|
* reserved page. In this case, set PagePrivate so that the
|
|
* global reserve count will be incremented to match the
|
|
* reservation map entry which was created.
|
|
*
|
|
* Note that vm_alloc_shared is based on the flags of the vma
|
|
* for which the page was originally allocated. dst_vma could
|
|
* be different or NULL on error.
|
|
*/
|
|
if (vm_alloc_shared)
|
|
SetPagePrivate(page);
|
|
else
|
|
ClearPagePrivate(page);
|
|
put_page(page);
|
|
}
|
|
BUG_ON(copied < 0);
|
|
BUG_ON(err > 0);
|
|
BUG_ON(!copied && !err);
|
|
return copied ? copied : err;
|
|
}
|
|
#else /* !CONFIG_HUGETLB_PAGE */
|
|
/* fail at build time if gcc attempts to use this */
|
|
extern ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
|
|
struct vm_area_struct *dst_vma,
|
|
unsigned long dst_start,
|
|
unsigned long src_start,
|
|
unsigned long len,
|
|
bool zeropage);
|
|
#endif /* CONFIG_HUGETLB_PAGE */
|
|
|
|
static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm,
|
|
pmd_t *dst_pmd,
|
|
struct vm_area_struct *dst_vma,
|
|
unsigned long dst_addr,
|
|
unsigned long src_addr,
|
|
struct page **page,
|
|
bool zeropage)
|
|
{
|
|
ssize_t err;
|
|
|
|
if (vma_is_anonymous(dst_vma)) {
|
|
if (!zeropage)
|
|
err = mcopy_atomic_pte(dst_mm, dst_pmd, dst_vma,
|
|
dst_addr, src_addr, page);
|
|
else
|
|
err = mfill_zeropage_pte(dst_mm, dst_pmd,
|
|
dst_vma, dst_addr);
|
|
} else {
|
|
if (!zeropage)
|
|
err = shmem_mcopy_atomic_pte(dst_mm, dst_pmd,
|
|
dst_vma, dst_addr,
|
|
src_addr, page);
|
|
else
|
|
err = shmem_mfill_zeropage_pte(dst_mm, dst_pmd,
|
|
dst_vma, dst_addr);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm,
|
|
unsigned long dst_start,
|
|
unsigned long src_start,
|
|
unsigned long len,
|
|
bool zeropage)
|
|
{
|
|
struct vm_area_struct *dst_vma;
|
|
ssize_t err;
|
|
pmd_t *dst_pmd;
|
|
unsigned long src_addr, dst_addr;
|
|
long copied;
|
|
struct page *page;
|
|
|
|
/*
|
|
* Sanitize the command parameters:
|
|
*/
|
|
BUG_ON(dst_start & ~PAGE_MASK);
|
|
BUG_ON(len & ~PAGE_MASK);
|
|
|
|
/* Does the address range wrap, or is the span zero-sized? */
|
|
BUG_ON(src_start + len <= src_start);
|
|
BUG_ON(dst_start + len <= dst_start);
|
|
|
|
src_addr = src_start;
|
|
dst_addr = dst_start;
|
|
copied = 0;
|
|
page = NULL;
|
|
retry:
|
|
down_read(&dst_mm->mmap_sem);
|
|
|
|
/*
|
|
* Make sure the vma is not shared, that the dst range is
|
|
* both valid and fully within a single existing vma.
|
|
*/
|
|
err = -ENOENT;
|
|
dst_vma = find_vma(dst_mm, dst_start);
|
|
if (!dst_vma)
|
|
goto out_unlock;
|
|
/*
|
|
* Be strict and only allow __mcopy_atomic on userfaultfd
|
|
* registered ranges to prevent userland errors going
|
|
* unnoticed. As far as the VM consistency is concerned, it
|
|
* would be perfectly safe to remove this check, but there's
|
|
* no useful usage for __mcopy_atomic ouside of userfaultfd
|
|
* registered ranges. This is after all why these are ioctls
|
|
* belonging to the userfaultfd and not syscalls.
|
|
*/
|
|
if (!dst_vma->vm_userfaultfd_ctx.ctx)
|
|
goto out_unlock;
|
|
|
|
if (dst_start < dst_vma->vm_start ||
|
|
dst_start + len > dst_vma->vm_end)
|
|
goto out_unlock;
|
|
|
|
err = -EINVAL;
|
|
/*
|
|
* shmem_zero_setup is invoked in mmap for MAP_ANONYMOUS|MAP_SHARED but
|
|
* it will overwrite vm_ops, so vma_is_anonymous must return false.
|
|
*/
|
|
if (WARN_ON_ONCE(vma_is_anonymous(dst_vma) &&
|
|
dst_vma->vm_flags & VM_SHARED))
|
|
goto out_unlock;
|
|
|
|
/*
|
|
* If this is a HUGETLB vma, pass off to appropriate routine
|
|
*/
|
|
if (is_vm_hugetlb_page(dst_vma))
|
|
return __mcopy_atomic_hugetlb(dst_mm, dst_vma, dst_start,
|
|
src_start, len, zeropage);
|
|
|
|
if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma))
|
|
goto out_unlock;
|
|
|
|
/*
|
|
* Ensure the dst_vma has a anon_vma or this page
|
|
* would get a NULL anon_vma when moved in the
|
|
* dst_vma.
|
|
*/
|
|
err = -ENOMEM;
|
|
if (vma_is_anonymous(dst_vma) && unlikely(anon_vma_prepare(dst_vma)))
|
|
goto out_unlock;
|
|
|
|
while (src_addr < src_start + len) {
|
|
pmd_t dst_pmdval;
|
|
|
|
BUG_ON(dst_addr >= dst_start + len);
|
|
|
|
dst_pmd = mm_alloc_pmd(dst_mm, dst_addr);
|
|
if (unlikely(!dst_pmd)) {
|
|
err = -ENOMEM;
|
|
break;
|
|
}
|
|
|
|
dst_pmdval = pmd_read_atomic(dst_pmd);
|
|
/*
|
|
* If the dst_pmd is mapped as THP don't
|
|
* override it and just be strict.
|
|
*/
|
|
if (unlikely(pmd_trans_huge(dst_pmdval))) {
|
|
err = -EEXIST;
|
|
break;
|
|
}
|
|
if (unlikely(pmd_none(dst_pmdval)) &&
|
|
unlikely(__pte_alloc(dst_mm, dst_pmd, dst_addr))) {
|
|
err = -ENOMEM;
|
|
break;
|
|
}
|
|
/* If an huge pmd materialized from under us fail */
|
|
if (unlikely(pmd_trans_huge(*dst_pmd))) {
|
|
err = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
BUG_ON(pmd_none(*dst_pmd));
|
|
BUG_ON(pmd_trans_huge(*dst_pmd));
|
|
|
|
err = mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr,
|
|
src_addr, &page, zeropage);
|
|
cond_resched();
|
|
|
|
if (unlikely(err == -EFAULT)) {
|
|
void *page_kaddr;
|
|
|
|
up_read(&dst_mm->mmap_sem);
|
|
BUG_ON(!page);
|
|
|
|
page_kaddr = kmap(page);
|
|
err = copy_from_user(page_kaddr,
|
|
(const void __user *) src_addr,
|
|
PAGE_SIZE);
|
|
kunmap(page);
|
|
if (unlikely(err)) {
|
|
err = -EFAULT;
|
|
goto out;
|
|
}
|
|
goto retry;
|
|
} else
|
|
BUG_ON(page);
|
|
|
|
if (!err) {
|
|
dst_addr += PAGE_SIZE;
|
|
src_addr += PAGE_SIZE;
|
|
copied += PAGE_SIZE;
|
|
|
|
if (fatal_signal_pending(current))
|
|
err = -EINTR;
|
|
}
|
|
if (err)
|
|
break;
|
|
}
|
|
|
|
out_unlock:
|
|
up_read(&dst_mm->mmap_sem);
|
|
out:
|
|
if (page)
|
|
put_page(page);
|
|
BUG_ON(copied < 0);
|
|
BUG_ON(err > 0);
|
|
BUG_ON(!copied && !err);
|
|
return copied ? copied : err;
|
|
}
|
|
|
|
ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
|
|
unsigned long src_start, unsigned long len)
|
|
{
|
|
return __mcopy_atomic(dst_mm, dst_start, src_start, len, false);
|
|
}
|
|
|
|
ssize_t mfill_zeropage(struct mm_struct *dst_mm, unsigned long start,
|
|
unsigned long len)
|
|
{
|
|
return __mcopy_atomic(dst_mm, start, 0, len, true);
|
|
}
|