#include <linux/swap.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
+#include <linux/ksm.h>
#include <linux/rmap.h>
#include <linux/module.h>
#include <linux/delayacct.h>
#include <linux/writeback.h>
#include <linux/memcontrol.h>
#include <linux/mmu_notifier.h>
+#include <linux/kallsyms.h>
+#include <linux/swapops.h>
+#include <linux/elf.h>
+#include <asm/io.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/pgtable.h>
-#include <linux/swapops.h>
-#include <linux/elf.h>
-
#include "internal.h"
#ifndef CONFIG_NEED_MULTIPLE_NODES
* Note: this doesn't free the actual pages themselves. That
* has been handled earlier when unmapping all the memory regions.
*/
-static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
+static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
+ unsigned long addr)
{
pgtable_t token = pmd_pgtable(*pmd);
pmd_clear(pmd);
- pte_free_tlb(tlb, token);
+ pte_free_tlb(tlb, token, addr);
tlb->mm->nr_ptes--;
}
next = pmd_addr_end(addr, end);
if (pmd_none_or_clear_bad(pmd))
continue;
- free_pte_range(tlb, pmd);
+ free_pte_range(tlb, pmd, addr);
} while (pmd++, addr = next, addr != end);
start &= PUD_MASK;
pmd = pmd_offset(pud, start);
pud_clear(pud);
- pmd_free_tlb(tlb, pmd);
+ pmd_free_tlb(tlb, pmd, start);
}
static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
pud = pud_offset(pgd, start);
pgd_clear(pgd);
- pud_free_tlb(tlb, pud);
+ pud_free_tlb(tlb, pud, start);
}
/*
*
* The calling function must still handle the error.
*/
-static void print_bad_pte(struct vm_area_struct *vma, pte_t pte,
- unsigned long vaddr)
-{
- printk(KERN_ERR "Bad pte = %08llx, process = %s, "
- "vm_flags = %lx, vaddr = %lx\n",
- (long long)pte_val(pte),
- (vma->vm_mm == current->mm ? current->comm : "???"),
- vma->vm_flags, vaddr);
+static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
+ pte_t pte, struct page *page)
+{
+ pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
+ pud_t *pud = pud_offset(pgd, addr);
+ pmd_t *pmd = pmd_offset(pud, addr);
+ struct address_space *mapping;
+ pgoff_t index;
+ static unsigned long resume;
+ static unsigned long nr_shown;
+ static unsigned long nr_unshown;
+
+ /*
+ * Allow a burst of 60 reports, then keep quiet for that minute;
+ * or allow a steady drip of one report per second.
+ */
+ if (nr_shown == 60) {
+ if (time_before(jiffies, resume)) {
+ nr_unshown++;
+ return;
+ }
+ if (nr_unshown) {
+ printk(KERN_ALERT
+ "BUG: Bad page map: %lu messages suppressed\n",
+ nr_unshown);
+ nr_unshown = 0;
+ }
+ nr_shown = 0;
+ }
+ if (nr_shown++ == 0)
+ resume = jiffies + 60 * HZ;
+
+ mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
+ index = linear_page_index(vma, addr);
+
+ printk(KERN_ALERT
+ "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
+ current->comm,
+ (long long)pte_val(pte), (long long)pmd_val(*pmd));
+ if (page) {
+ printk(KERN_ALERT
+ "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
+ page, (void *)page->flags, page_count(page),
+ page_mapcount(page), page->mapping, page->index);
+ }
+ printk(KERN_ALERT
+ "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
+ (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
+ /*
+ * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
+ */
+ if (vma->vm_ops)
+ print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n",
+ (unsigned long)vma->vm_ops->fault);
+ if (vma->vm_file && vma->vm_file->f_op)
+ print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n",
+ (unsigned long)vma->vm_file->f_op->mmap);
dump_stack();
+ add_taint(TAINT_BAD_PAGE);
}
static inline int is_cow_mapping(unsigned int flags)
struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
pte_t pte)
{
- unsigned long pfn;
+ unsigned long pfn = pte_pfn(pte);
if (HAVE_PTE_SPECIAL) {
- if (likely(!pte_special(pte))) {
- VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
- return pte_page(pte);
- }
- VM_BUG_ON(!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)));
+ if (likely(!pte_special(pte)))
+ goto check_pfn;
+ if (!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)))
+ print_bad_pte(vma, addr, pte, NULL);
return NULL;
}
/* !HAVE_PTE_SPECIAL case follows: */
- pfn = pte_pfn(pte);
-
if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
if (vma->vm_flags & VM_MIXEDMAP) {
if (!pfn_valid(pfn))
}
}
- VM_BUG_ON(!pfn_valid(pfn));
+check_pfn:
+ if (unlikely(pfn > highest_memmap_pfn)) {
+ print_bad_pte(vma, addr, pte, NULL);
+ return NULL;
+ }
/*
* NOTE! We still have PageReserved() pages in the page tables.
- *
* eg. VDSO mappings can cause them to exist.
*/
out:
page = vm_normal_page(vma, addr, pte);
if (page) {
get_page(page);
- page_dup_rmap(page, vma, addr);
+ page_dup_rmap(page);
rss[!!PageAnon(page)]++;
}
mark_page_accessed(page);
file_rss--;
}
- page_remove_rmap(page, vma);
+ page_remove_rmap(page);
+ if (unlikely(page_mapcount(page) < 0))
+ print_bad_pte(vma, addr, ptent, page);
tlb_remove_page(tlb, page);
continue;
}
*/
if (unlikely(details))
continue;
- if (!pte_file(ptent))
- free_swap_and_cache(pte_to_swp_entry(ptent));
+ if (pte_file(ptent)) {
+ if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
+ print_bad_pte(vma, addr, ptent, NULL);
+ } else if
+ (unlikely(!free_swap_and_cache(pte_to_swp_entry(ptent))))
+ print_bad_pte(vma, addr, ptent, NULL);
pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
} while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
if ((flags & FOLL_WRITE) &&
!pte_dirty(pte) && !PageDirty(page))
set_page_dirty(page);
+ /*
+ * pte_mkyoung() would be more correct here, but atomic care
+ * is needed to avoid losing the dirty bit: it is easier to use
+ * mark_page_accessed().
+ */
mark_page_accessed(page);
}
unlock:
int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, int len, int flags,
- struct page **pages, struct vm_area_struct **vmas)
+ unsigned long start, int nr_pages, int flags,
+ struct page **pages, struct vm_area_struct **vmas)
{
int i;
unsigned int vm_flags = 0;
int write = !!(flags & GUP_FLAGS_WRITE);
int force = !!(flags & GUP_FLAGS_FORCE);
int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS);
+ int ignore_sigkill = !!(flags & GUP_FLAGS_IGNORE_SIGKILL);
- if (len <= 0)
+ if (nr_pages <= 0)
return 0;
/*
* Require read or write permissions.
vmas[i] = gate_vma;
i++;
start += PAGE_SIZE;
- len--;
+ nr_pages--;
continue;
}
if (is_vm_hugetlb_page(vma)) {
i = follow_hugetlb_page(mm, vma, pages, vmas,
- &start, &len, i, write);
+ &start, &nr_pages, i, write);
continue;
}
struct page *page;
/*
- * If tsk is ooming, cut off its access to large memory
- * allocations. It has a pending SIGKILL, but it can't
- * be processed until returning to user space.
+ * If we have a pending SIGKILL, don't keep faulting
+ * pages and potentially allocating memory, unless
+ * current is handling munlock--e.g., on exit. In
+ * that case, we are not allocating memory. Rather,
+ * we're only unlocking already resident/mapped pages.
*/
- if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE)))
- return i ? i : -ENOMEM;
+ if (unlikely(!ignore_sigkill &&
+ fatal_signal_pending(current)))
+ return i ? i : -ERESTARTSYS;
if (write)
foll_flags |= FOLL_WRITE;
cond_resched();
while (!(page = follow_page(vma, start, foll_flags))) {
int ret;
+
ret = handle_mm_fault(mm, vma, start,
- foll_flags & FOLL_WRITE);
+ (foll_flags & FOLL_WRITE) ?
+ FAULT_FLAG_WRITE : 0);
+
if (ret & VM_FAULT_ERROR) {
if (ret & VM_FAULT_OOM)
return i ? i : -ENOMEM;
vmas[i] = vma;
i++;
start += PAGE_SIZE;
- len--;
- } while (len && start < vma->vm_end);
- } while (len);
+ nr_pages--;
+ } while (nr_pages && start < vma->vm_end);
+ } while (nr_pages);
return i;
}
+/**
+ * get_user_pages() - pin user pages in memory
+ * @tsk: task_struct of target task
+ * @mm: mm_struct of target mm
+ * @start: starting user address
+ * @nr_pages: number of pages from start to pin
+ * @write: whether pages will be written to by the caller
+ * @force: whether to force write access even if user mapping is
+ * readonly. This will result in the page being COWed even
+ * in MAP_SHARED mappings. You do not want this.
+ * @pages: array that receives pointers to the pages pinned.
+ * Should be at least nr_pages long. Or NULL, if caller
+ * only intends to ensure the pages are faulted in.
+ * @vmas: array of pointers to vmas corresponding to each page.
+ * Or NULL if the caller does not require them.
+ *
+ * Returns number of pages pinned. This may be fewer than the number
+ * requested. If nr_pages is 0 or negative, returns 0. If no pages
+ * were pinned, returns -errno. Each page returned must be released
+ * with a put_page() call when it is finished with. vmas will only
+ * remain valid while mmap_sem is held.
+ *
+ * Must be called with mmap_sem held for read or write.
+ *
+ * get_user_pages walks a process's page tables and takes a reference to
+ * each struct page that each user address corresponds to at a given
+ * instant. That is, it takes the page that would be accessed if a user
+ * thread accesses the given user virtual address at that instant.
+ *
+ * This does not guarantee that the page exists in the user mappings when
+ * get_user_pages returns, and there may even be a completely different
+ * page there in some cases (eg. if mmapped pagecache has been invalidated
+ * and subsequently re faulted). However it does guarantee that the page
+ * won't be freed completely. And mostly callers simply care that the page
+ * contains data that was valid *at some point in time*. Typically, an IO
+ * or similar operation cannot guarantee anything stronger anyway because
+ * locks can't be held over the syscall boundary.
+ *
+ * If write=0, the page must not be written to. If the page is written to,
+ * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
+ * after the page is finished with, and before put_page is called.
+ *
+ * get_user_pages is typically used for fewer-copy IO operations, to get a
+ * handle on the memory by some means other than accesses via the user virtual
+ * addresses. The pages may be submitted for DMA to devices or accessed via
+ * their kernel linear mapping (via the kmap APIs). Care should be taken to
+ * use the correct cache flushing APIs.
+ *
+ * See also get_user_pages_fast, for performance critical applications.
+ */
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, int len, int write, int force,
+ unsigned long start, int nr_pages, int write, int force,
struct page **pages, struct vm_area_struct **vmas)
{
int flags = 0;
if (force)
flags |= GUP_FLAGS_FORCE;
- return __get_user_pages(tsk, mm,
- start, len, flags,
- pages, vmas);
+ return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
}
EXPORT_SYMBOL(get_user_pages);
unsigned long pfn)
{
int ret;
+ pgprot_t pgprot = vma->vm_page_prot;
/*
* Technically, architectures with pte_special can avoid all these
* restrictions (same for remap_pfn_range). However we would like
if (addr < vma->vm_start || addr >= vma->vm_end)
return -EFAULT;
- if (track_pfn_vma_new(vma, vma->vm_page_prot, pfn, PAGE_SIZE))
+ if (track_pfn_vma_new(vma, &pgprot, pfn, PAGE_SIZE))
return -EINVAL;
- ret = insert_pfn(vma, addr, pfn, vma->vm_page_prot);
+ ret = insert_pfn(vma, addr, pfn, pgprot);
if (ret)
untrack_pfn_vma(vma, pfn, PAGE_SIZE);
* behaviour that some programs depend on. We mark the "original"
* un-COW'ed pages by matching them up with "vma->vm_pgoff".
*/
- if (addr == vma->vm_start && end == vma->vm_end)
+ if (addr == vma->vm_start && end == vma->vm_end) {
vma->vm_pgoff = pfn;
- else if (is_cow_mapping(vma->vm_flags))
+ vma->vm_flags |= VM_PFN_AT_MMAP;
+ } else if (is_cow_mapping(vma->vm_flags))
return -EINVAL;
vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
- err = track_pfn_vma_new(vma, prot, pfn, PAGE_ALIGN(size));
- if (err)
+ err = track_pfn_vma_new(vma, &prot, pfn, PAGE_ALIGN(size));
+ if (err) {
+ /*
+ * To indicate that track_pfn related cleanup is not
+ * needed from higher level routine calling unmap_vmas
+ */
+ vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
+ vma->vm_flags &= ~VM_PFN_AT_MMAP;
return -EINVAL;
+ }
BUG_ON(addr >= end);
pfn -= addr >> PAGE_SHIFT;
* Take out anonymous pages first, anonymous shared vmas are
* not dirty accountable.
*/
- if (PageAnon(old_page)) {
+ if (PageAnon(old_page) && !PageKsm(old_page)) {
if (!trylock_page(old_page)) {
page_cache_get(old_page);
pte_unmap_unlock(page_table, ptl);
}
page_cache_release(old_page);
}
- reuse = can_share_swap_page(old_page);
+ reuse = reuse_swap_page(old_page);
unlock_page(old_page);
} else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
(VM_WRITE|VM_SHARED))) {
* get_user_pages(.write=1, .force=1).
*/
if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
+ struct vm_fault vmf;
+ int tmp;
+
+ vmf.virtual_address = (void __user *)(address &
+ PAGE_MASK);
+ vmf.pgoff = old_page->index;
+ vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
+ vmf.page = old_page;
+
/*
* Notify the address space that the page is about to
* become writable so that it can prohibit this or wait
page_cache_get(old_page);
pte_unmap_unlock(page_table, ptl);
- if (vma->vm_ops->page_mkwrite(vma, old_page) < 0)
+ tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
+ if (unlikely(tmp &
+ (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
+ ret = tmp;
goto unwritable_page;
+ }
+ if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
+ lock_page(old_page);
+ if (!old_page->mapping) {
+ ret = 0; /* retry the fault */
+ unlock_page(old_page);
+ goto unwritable_page;
+ }
+ } else
+ VM_BUG_ON(!PageLocked(old_page));
/*
* Since we dropped the lock we need to revalidate
*/
page_table = pte_offset_map_lock(mm, pmd, address,
&ptl);
- page_cache_release(old_page);
- if (!pte_same(*page_table, orig_pte))
+ if (!pte_same(*page_table, orig_pte)) {
+ unlock_page(old_page);
+ page_cache_release(old_page);
goto unlock;
+ }
page_mkwrite = 1;
}
* Don't let another task, with possibly unlocked vma,
* keep the mlocked page.
*/
- if (vma->vm_flags & VM_LOCKED) {
+ if ((vma->vm_flags & VM_LOCKED) && old_page) {
lock_page(old_page); /* for LRU manipulation */
clear_page_mlock(old_page);
unlock_page(old_page);
cow_user_page(new_page, old_page, address, vma);
__SetPageUptodate(new_page);
- if (mem_cgroup_charge(new_page, mm, GFP_KERNEL))
+ if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
goto oom_free_new;
/*
* seen in the presence of one thread doing SMC and another
* thread doing COW.
*/
- ptep_clear_flush_notify(vma, address, page_table);
+ ptep_clear_flush(vma, address, page_table);
page_add_new_anon_rmap(new_page, vma, address);
- set_pte_at(mm, address, page_table, entry);
+ /*
+ * We call the notify macro here because, when using secondary
+ * mmu page tables (such as kvm shadow page tables), we want the
+ * new page to be mapped directly into the secondary page table.
+ */
+ set_pte_at_notify(mm, address, page_table, entry);
update_mmu_cache(vma, address, entry);
if (old_page) {
/*
* mapcount is visible. So transitively, TLBs to
* old page will be flushed before it can be reused.
*/
- page_remove_rmap(old_page, vma);
+ page_remove_rmap(old_page);
}
/* Free the old page.. */
unlock:
pte_unmap_unlock(page_table, ptl);
if (dirty_page) {
- if (vma->vm_file)
- file_update_time(vma->vm_file);
-
/*
* Yes, Virginia, this is actually required to prevent a race
* with clear_page_dirty_for_io() from clearing the page dirty
*
* do_no_page is protected similarly.
*/
- wait_on_page_locked(dirty_page);
- set_page_dirty_balance(dirty_page, page_mkwrite);
+ if (!page_mkwrite) {
+ wait_on_page_locked(dirty_page);
+ set_page_dirty_balance(dirty_page, page_mkwrite);
+ }
put_page(dirty_page);
+ if (page_mkwrite) {
+ struct address_space *mapping = dirty_page->mapping;
+
+ set_page_dirty(dirty_page);
+ unlock_page(dirty_page);
+ page_cache_release(dirty_page);
+ if (mapping) {
+ /*
+ * Some device drivers do not set page.mapping
+ * but still dirty their pages
+ */
+ balance_dirty_pages_ratelimited(mapping);
+ }
+ }
+
+ /* file_update_time outside page_lock */
+ if (vma->vm_file)
+ file_update_time(vma->vm_file);
}
return ret;
oom_free_new:
page_cache_release(new_page);
oom:
- if (old_page)
+ if (old_page) {
+ if (page_mkwrite) {
+ unlock_page(old_page);
+ page_cache_release(old_page);
+ }
page_cache_release(old_page);
+ }
return VM_FAULT_OOM;
unwritable_page:
page_cache_release(old_page);
- return VM_FAULT_SIGBUS;
+ return ret;
}
/*
*/
static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
- int write_access, pte_t orig_pte)
+ unsigned int flags, pte_t orig_pte)
{
spinlock_t *ptl;
struct page *page;
swp_entry_t entry;
pte_t pte;
+ struct mem_cgroup *ptr = NULL;
int ret = 0;
if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
delayacct_set_flag(DELAYACCT_PF_SWAPIN);
page = lookup_swap_cache(entry);
if (!page) {
- grab_swap_token(); /* Contend for token _before_ read-in */
+ grab_swap_token(mm); /* Contend for token _before_ read-in */
page = swapin_readahead(entry,
GFP_HIGHUSER_MOVABLE, vma, address);
if (!page) {
count_vm_event(PGMAJFAULT);
}
- mark_page_accessed(page);
-
lock_page(page);
delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
- if (mem_cgroup_charge(page, mm, GFP_KERNEL)) {
+ if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
ret = VM_FAULT_OOM;
- unlock_page(page);
- goto out;
+ goto out_page;
}
/*
goto out_nomap;
}
- /* The page isn't present yet, go ahead with the fault. */
+ /*
+ * The page isn't present yet, go ahead with the fault.
+ *
+ * Be careful about the sequence of operations here.
+ * To get its accounting right, reuse_swap_page() must be called
+ * while the page is counted on swap but not yet in mapcount i.e.
+ * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
+ * must be called after the swap_free(), or it will never succeed.
+ * Because delete_from_swap_page() may be called by reuse_swap_page(),
+ * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
+ * in page->private. In this case, a record in swap_cgroup is silently
+ * discarded at swap_free().
+ */
inc_mm_counter(mm, anon_rss);
pte = mk_pte(page, vma->vm_page_prot);
- if (write_access && can_share_swap_page(page)) {
+ if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
pte = maybe_mkwrite(pte_mkdirty(pte), vma);
- write_access = 0;
+ flags &= ~FAULT_FLAG_WRITE;
}
-
flush_icache_page(vma, page);
set_pte_at(mm, address, page_table, pte);
page_add_anon_rmap(page, vma, address);
+ /* It's better to call commit-charge after rmap is established */
+ mem_cgroup_commit_charge_swapin(page, ptr);
swap_free(entry);
if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
- remove_exclusive_swap_page(page);
+ try_to_free_swap(page);
unlock_page(page);
- if (write_access) {
+ if (flags & FAULT_FLAG_WRITE) {
ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
if (ret & VM_FAULT_ERROR)
ret &= VM_FAULT_ERROR;
out:
return ret;
out_nomap:
- mem_cgroup_uncharge_page(page);
+ mem_cgroup_cancel_charge_swapin(ptr);
pte_unmap_unlock(page_table, ptl);
+out_page:
unlock_page(page);
page_cache_release(page);
return ret;
*/
static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
- int write_access)
+ unsigned int flags)
{
struct page *page;
spinlock_t *ptl;
goto oom;
__SetPageUptodate(page);
- if (mem_cgroup_charge(page, mm, GFP_KERNEL))
+ if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
goto oom_free_page;
entry = mk_pte(page, vma->vm_page_prot);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
- if (!pte_none(*page_table))
+ if (!pte_none(*page_table) || ksm_test_exit(mm))
goto release;
+
inc_mm_counter(mm, anon_rss);
page_add_new_anon_rmap(page, vma, address);
set_pte_at(mm, address, page_table, entry);
ret = VM_FAULT_OOM;
goto out;
}
- if (mem_cgroup_charge(page, mm, GFP_KERNEL)) {
+ if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
ret = VM_FAULT_OOM;
page_cache_release(page);
goto out;
* to become writable
*/
if (vma->vm_ops->page_mkwrite) {
+ int tmp;
+
unlock_page(page);
- if (vma->vm_ops->page_mkwrite(vma, page) < 0) {
- ret = VM_FAULT_SIGBUS;
- anon = 1; /* no anon but release vmf.page */
- goto out_unlocked;
- }
- lock_page(page);
- /*
- * XXX: this is not quite right (racy vs
- * invalidate) to unlock and relock the page
- * like this, however a better fix requires
- * reworking page_mkwrite locking API, which
- * is better done later.
- */
- if (!page->mapping) {
- ret = 0;
- anon = 1; /* no anon but release vmf.page */
- goto out;
+ vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
+ tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
+ if (unlikely(tmp &
+ (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
+ ret = tmp;
+ goto unwritable_page;
}
+ if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
+ lock_page(page);
+ if (!page->mapping) {
+ ret = 0; /* retry the fault */
+ unlock_page(page);
+ goto unwritable_page;
+ }
+ } else
+ VM_BUG_ON(!PageLocked(page));
page_mkwrite = 1;
}
}
* due to the bad i386 page protection. But it's valid
* for other architectures too.
*
- * Note that if write_access is true, we either now have
+ * Note that if FAULT_FLAG_WRITE is set, we either now have
* an exclusive copy of the page, or this is a shared mapping,
* so we can make it writable and dirty to avoid having to
* handle that later.
*/
/* Only go through if we didn't race with anybody else... */
- if (likely(pte_same(*page_table, orig_pte))) {
+ if (likely(pte_same(*page_table, orig_pte) && !ksm_test_exit(mm))) {
flush_icache_page(vma, page);
entry = mk_pte(page, vma->vm_page_prot);
if (flags & FAULT_FLAG_WRITE)
pte_unmap_unlock(page_table, ptl);
out:
- unlock_page(vmf.page);
-out_unlocked:
- if (anon)
- page_cache_release(vmf.page);
- else if (dirty_page) {
- if (vma->vm_file)
- file_update_time(vma->vm_file);
+ if (dirty_page) {
+ struct address_space *mapping = page->mapping;
- set_page_dirty_balance(dirty_page, page_mkwrite);
+ if (set_page_dirty(dirty_page))
+ page_mkwrite = 1;
+ unlock_page(dirty_page);
put_page(dirty_page);
+ if (page_mkwrite && mapping) {
+ /*
+ * Some device drivers do not set page.mapping but still
+ * dirty their pages
+ */
+ balance_dirty_pages_ratelimited(mapping);
+ }
+
+ /* file_update_time outside page_lock */
+ if (vma->vm_file)
+ file_update_time(vma->vm_file);
+ } else {
+ unlock_page(vmf.page);
+ if (anon)
+ page_cache_release(vmf.page);
}
return ret;
+
+unwritable_page:
+ page_cache_release(page);
+ return ret;
}
static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
- int write_access, pte_t orig_pte)
+ unsigned int flags, pte_t orig_pte)
{
pgoff_t pgoff = (((address & PAGE_MASK)
- vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
- unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0);
pte_unmap(page_table);
return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
*/
static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
- int write_access, pte_t orig_pte)
+ unsigned int flags, pte_t orig_pte)
{
- unsigned int flags = FAULT_FLAG_NONLINEAR |
- (write_access ? FAULT_FLAG_WRITE : 0);
pgoff_t pgoff;
+ flags |= FAULT_FLAG_NONLINEAR;
+
if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
return 0;
- if (unlikely(!(vma->vm_flags & VM_NONLINEAR) ||
- !(vma->vm_flags & VM_CAN_NONLINEAR))) {
+ if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
/*
* Page table corrupted: show pte and kill process.
*/
- print_bad_pte(vma, orig_pte, address);
+ print_bad_pte(vma, address, orig_pte, NULL);
return VM_FAULT_OOM;
}
*/
static inline int handle_pte_fault(struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long address,
- pte_t *pte, pmd_t *pmd, int write_access)
+ pte_t *pte, pmd_t *pmd, unsigned int flags)
{
pte_t entry;
spinlock_t *ptl;
if (vma->vm_ops) {
if (likely(vma->vm_ops->fault))
return do_linear_fault(mm, vma, address,
- pte, pmd, write_access, entry);
+ pte, pmd, flags, entry);
}
return do_anonymous_page(mm, vma, address,
- pte, pmd, write_access);
+ pte, pmd, flags);
}
if (pte_file(entry))
return do_nonlinear_fault(mm, vma, address,
- pte, pmd, write_access, entry);
+ pte, pmd, flags, entry);
return do_swap_page(mm, vma, address,
- pte, pmd, write_access, entry);
+ pte, pmd, flags, entry);
}
ptl = pte_lockptr(mm, pmd);
spin_lock(ptl);
if (unlikely(!pte_same(*pte, entry)))
goto unlock;
- if (write_access) {
+ if (flags & FAULT_FLAG_WRITE) {
if (!pte_write(entry))
return do_wp_page(mm, vma, address,
pte, pmd, ptl, entry);
entry = pte_mkdirty(entry);
}
entry = pte_mkyoung(entry);
- if (ptep_set_access_flags(vma, address, pte, entry, write_access)) {
+ if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
update_mmu_cache(vma, address, entry);
} else {
/*
* This still avoids useless tlb flushes for .text page faults
* with threads.
*/
- if (write_access)
+ if (flags & FAULT_FLAG_WRITE)
flush_tlb_page(vma, address);
}
unlock:
* By the time we get here, we already hold the mm semaphore
*/
int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long address, int write_access)
+ unsigned long address, unsigned int flags)
{
pgd_t *pgd;
pud_t *pud;
count_vm_event(PGFAULT);
if (unlikely(is_vm_hugetlb_page(vma)))
- return hugetlb_fault(mm, vma, address, write_access);
+ return hugetlb_fault(mm, vma, address, flags);
pgd = pgd_offset(mm, address);
pud = pud_alloc(mm, pgd, address);
if (!pte)
return VM_FAULT_OOM;
- return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
+ return handle_pte_fault(mm, vma, address, pte, pmd, flags);
}
#ifndef __PAGETABLE_PUD_FOLDED
#endif /* __HAVE_ARCH_GATE_AREA */
-#ifdef CONFIG_HAVE_IOREMAP_PROT
-int follow_phys(struct vm_area_struct *vma,
- unsigned long address, unsigned int flags,
- unsigned long *prot, resource_size_t *phys)
+static int follow_pte(struct mm_struct *mm, unsigned long address,
+ pte_t **ptepp, spinlock_t **ptlp)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
- pte_t *ptep, pte;
- spinlock_t *ptl;
- resource_size_t phys_addr = 0;
- struct mm_struct *mm = vma->vm_mm;
- int ret = -EINVAL;
-
- if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
- goto out;
+ pte_t *ptep;
pgd = pgd_offset(mm, address);
if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
if (pmd_huge(*pmd))
goto out;
- ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
+ ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
if (!ptep)
goto out;
+ if (!pte_present(*ptep))
+ goto unlock;
+ *ptepp = ptep;
+ return 0;
+unlock:
+ pte_unmap_unlock(ptep, *ptlp);
+out:
+ return -EINVAL;
+}
+
+/**
+ * follow_pfn - look up PFN at a user virtual address
+ * @vma: memory mapping
+ * @address: user virtual address
+ * @pfn: location to store found PFN
+ *
+ * Only IO mappings and raw PFN mappings are allowed.
+ *
+ * Returns zero and the pfn at @pfn on success, -ve otherwise.
+ */
+int follow_pfn(struct vm_area_struct *vma, unsigned long address,
+ unsigned long *pfn)
+{
+ int ret = -EINVAL;
+ spinlock_t *ptl;
+ pte_t *ptep;
+
+ if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+ return ret;
+
+ ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
+ if (ret)
+ return ret;
+ *pfn = pte_pfn(*ptep);
+ pte_unmap_unlock(ptep, ptl);
+ return 0;
+}
+EXPORT_SYMBOL(follow_pfn);
+
+#ifdef CONFIG_HAVE_IOREMAP_PROT
+int follow_phys(struct vm_area_struct *vma,
+ unsigned long address, unsigned int flags,
+ unsigned long *prot, resource_size_t *phys)
+{
+ int ret = -EINVAL;
+ pte_t *ptep, pte;
+ spinlock_t *ptl;
+
+ if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+ goto out;
+ if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
+ goto out;
pte = *ptep;
- if (!pte_present(pte))
- goto unlock;
+
if ((flags & FOLL_WRITE) && !pte_write(pte))
goto unlock;
- phys_addr = pte_pfn(pte);
- phys_addr <<= PAGE_SHIFT; /* Shift here to avoid overflow on PAE */
*prot = pgprot_val(pte_pgprot(pte));
- *phys = phys_addr;
- ret = 0;
+ *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
+ ret = 0;
unlock:
pte_unmap_unlock(ptep, ptl);
out:
{
resource_size_t phys_addr;
unsigned long prot = 0;
- void *maddr;
+ void __iomem *maddr;
int offset = addr & (PAGE_SIZE-1);
if (follow_phys(vma, addr, write, &prot, &phys_addr))
#ifdef CONFIG_PROVE_LOCKING
void might_fault(void)
{
+ /*
+ * Some code (nfs/sunrpc) uses socket ops on kernel memory while
+ * holding the mmap_sem, this is safe because kernel memory doesn't
+ * get paged out, therefore we'll never actually fault, and the
+ * below annotations will generate false positives.
+ */
+ if (segment_eq(get_fs(), KERNEL_DS))
+ return;
+
might_sleep();
/*
* it would be nicer only to annotate paths which are not under
Code Review / linux-2.6.git / blobdiff