*
* 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
* (Gerhard.Wichert@pdb.siemens.de)
+ *
+ * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
*/
#include <linux/kernel_stat.h>
#include <linux/swapops.h>
#include <linux/elf.h>
-#ifndef CONFIG_DISCONTIGMEM
+#ifndef CONFIG_NEED_MULTIPLE_NODES
/* use the per-pgdat data instead for discontigmem - mbligh */
unsigned long max_mapnr;
struct page *mem_map;
* and ZONE_HIGHMEM.
*/
void * high_memory;
-struct page *highmem_start_page;
unsigned long vmalloc_earlyreserve;
EXPORT_SYMBOL(num_physpages);
-EXPORT_SYMBOL(highmem_start_page);
EXPORT_SYMBOL(high_memory);
EXPORT_SYMBOL(vmalloc_earlyreserve);
+int randomize_va_space __read_mostly = 1;
+
+static int __init disable_randmaps(char *s)
+{
+ randomize_va_space = 0;
+ return 1;
+}
+__setup("norandmaps", disable_randmaps);
+
+
/*
- * We special-case the C-O-W ZERO_PAGE, because it's such
- * a common occurrence (no need to read the page to know
- * that it's zero - better for the cache and memory subsystem).
+ * If a p?d_bad entry is found while walking page tables, report
+ * the error, before resetting entry to p?d_none. Usually (but
+ * very seldom) called out from the p?d_none_or_clear_bad macros.
*/
-static inline void copy_cow_page(struct page * from, struct page * to, unsigned long address)
+
+void pgd_clear_bad(pgd_t *pgd)
{
- if (from == ZERO_PAGE(address)) {
- clear_user_highpage(to, address);
- return;
- }
- copy_user_highpage(to, from, address);
+ pgd_ERROR(*pgd);
+ pgd_clear(pgd);
+}
+
+void pud_clear_bad(pud_t *pud)
+{
+ pud_ERROR(*pud);
+ pud_clear(pud);
+}
+
+void pmd_clear_bad(pmd_t *pmd)
+{
+ pmd_ERROR(*pmd);
+ pmd_clear(pmd);
}
/*
* Note: this doesn't free the actual pages themselves. That
* has been handled earlier when unmapping all the memory regions.
*/
-static inline void free_one_pmd(struct mmu_gather *tlb, pmd_t * dir)
+static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
{
- struct page *page;
+ struct page *page = pmd_page(*pmd);
+ pmd_clear(pmd);
+ pte_lock_deinit(page);
+ pte_free_tlb(tlb, page);
+ dec_page_state(nr_page_table_pages);
+ tlb->mm->nr_ptes--;
+}
- if (pmd_none(*dir))
- return;
- if (unlikely(pmd_bad(*dir))) {
- pmd_ERROR(*dir);
- pmd_clear(dir);
+static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
+ unsigned long addr, unsigned long end,
+ unsigned long floor, unsigned long ceiling)
+{
+ pmd_t *pmd;
+ unsigned long next;
+ unsigned long start;
+
+ start = addr;
+ pmd = pmd_offset(pud, addr);
+ do {
+ next = pmd_addr_end(addr, end);
+ if (pmd_none_or_clear_bad(pmd))
+ continue;
+ free_pte_range(tlb, pmd);
+ } while (pmd++, addr = next, addr != end);
+
+ start &= PUD_MASK;
+ if (start < floor)
return;
+ if (ceiling) {
+ ceiling &= PUD_MASK;
+ if (!ceiling)
+ return;
}
- page = pmd_page(*dir);
- pmd_clear(dir);
- dec_page_state(nr_page_table_pages);
- pte_free_tlb(tlb, page);
+ if (end - 1 > ceiling - 1)
+ return;
+
+ pmd = pmd_offset(pud, start);
+ pud_clear(pud);
+ pmd_free_tlb(tlb, pmd);
}
-static inline void free_one_pgd(struct mmu_gather *tlb, pgd_t * dir)
+static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
+ unsigned long addr, unsigned long end,
+ unsigned long floor, unsigned long ceiling)
{
- int j;
- pmd_t * pmd;
+ pud_t *pud;
+ unsigned long next;
+ unsigned long start;
- if (pgd_none(*dir))
- return;
- if (unlikely(pgd_bad(*dir))) {
- pgd_ERROR(*dir);
- pgd_clear(dir);
+ start = addr;
+ pud = pud_offset(pgd, addr);
+ do {
+ next = pud_addr_end(addr, end);
+ if (pud_none_or_clear_bad(pud))
+ continue;
+ free_pmd_range(tlb, pud, addr, next, floor, ceiling);
+ } while (pud++, addr = next, addr != end);
+
+ start &= PGDIR_MASK;
+ if (start < floor)
return;
+ if (ceiling) {
+ ceiling &= PGDIR_MASK;
+ if (!ceiling)
+ return;
}
- pmd = pmd_offset(dir, 0);
- pgd_clear(dir);
- for (j = 0; j < PTRS_PER_PMD ; j++)
- free_one_pmd(tlb, pmd+j);
- pmd_free_tlb(tlb, pmd);
+ if (end - 1 > ceiling - 1)
+ return;
+
+ pud = pud_offset(pgd, start);
+ pgd_clear(pgd);
+ pud_free_tlb(tlb, pud);
}
/*
- * This function clears all user-level page tables of a process - this
- * is needed by execve(), so that old pages aren't in the way.
+ * This function frees user-level page tables of a process.
*
* Must be called with pagetable lock held.
*/
-void clear_page_tables(struct mmu_gather *tlb, unsigned long first, int nr)
+void free_pgd_range(struct mmu_gather **tlb,
+ unsigned long addr, unsigned long end,
+ unsigned long floor, unsigned long ceiling)
{
- pgd_t * page_dir = tlb->mm->pgd;
+ pgd_t *pgd;
+ unsigned long next;
+ unsigned long start;
+
+ /*
+ * The next few lines have given us lots of grief...
+ *
+ * Why are we testing PMD* at this top level? Because often
+ * there will be no work to do at all, and we'd prefer not to
+ * go all the way down to the bottom just to discover that.
+ *
+ * Why all these "- 1"s? Because 0 represents both the bottom
+ * of the address space and the top of it (using -1 for the
+ * top wouldn't help much: the masks would do the wrong thing).
+ * The rule is that addr 0 and floor 0 refer to the bottom of
+ * the address space, but end 0 and ceiling 0 refer to the top
+ * Comparisons need to use "end - 1" and "ceiling - 1" (though
+ * that end 0 case should be mythical).
+ *
+ * Wherever addr is brought up or ceiling brought down, we must
+ * be careful to reject "the opposite 0" before it confuses the
+ * subsequent tests. But what about where end is brought down
+ * by PMD_SIZE below? no, end can't go down to 0 there.
+ *
+ * Whereas we round start (addr) and ceiling down, by different
+ * masks at different levels, in order to test whether a table
+ * now has no other vmas using it, so can be freed, we don't
+ * bother to round floor or end up - the tests don't need that.
+ */
+
+ addr &= PMD_MASK;
+ if (addr < floor) {
+ addr += PMD_SIZE;
+ if (!addr)
+ return;
+ }
+ if (ceiling) {
+ ceiling &= PMD_MASK;
+ if (!ceiling)
+ return;
+ }
+ if (end - 1 > ceiling - 1)
+ end -= PMD_SIZE;
+ if (addr > end - 1)
+ return;
- page_dir += first;
+ start = addr;
+ pgd = pgd_offset((*tlb)->mm, addr);
do {
- free_one_pgd(tlb, page_dir);
- page_dir++;
- } while (--nr);
+ next = pgd_addr_end(addr, end);
+ if (pgd_none_or_clear_bad(pgd))
+ continue;
+ free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
+ } while (pgd++, addr = next, addr != end);
+
+ if (!(*tlb)->fullmm)
+ flush_tlb_pgtables((*tlb)->mm, start, end);
}
-pte_t fastcall * pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
+void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
+ unsigned long floor, unsigned long ceiling)
{
- if (!pmd_present(*pmd)) {
- struct page *new;
-
- spin_unlock(&mm->page_table_lock);
- new = pte_alloc_one(mm, address);
- spin_lock(&mm->page_table_lock);
- if (!new)
- return NULL;
+ while (vma) {
+ struct vm_area_struct *next = vma->vm_next;
+ unsigned long addr = vma->vm_start;
/*
- * Because we dropped the lock, we should re-check the
- * entry, as somebody else could have populated it..
+ * Hide vma from rmap and vmtruncate before freeing pgtables
*/
- if (pmd_present(*pmd)) {
- pte_free(new);
- goto out;
+ anon_vma_unlink(vma);
+ unlink_file_vma(vma);
+
+ if (is_vm_hugetlb_page(vma)) {
+ hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
+ floor, next? next->vm_start: ceiling);
+ } else {
+ /*
+ * Optimization: gather nearby vmas into one call down
+ */
+ while (next && next->vm_start <= vma->vm_end + PMD_SIZE
+ && !is_vm_hugetlb_page(next)) {
+ vma = next;
+ next = vma->vm_next;
+ anon_vma_unlink(vma);
+ unlink_file_vma(vma);
+ }
+ free_pgd_range(tlb, addr, vma->vm_end,
+ floor, next? next->vm_start: ceiling);
}
+ vma = next;
+ }
+}
+
+int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
+{
+ struct page *new = pte_alloc_one(mm, address);
+ if (!new)
+ return -ENOMEM;
+
+ pte_lock_init(new);
+ spin_lock(&mm->page_table_lock);
+ if (pmd_present(*pmd)) { /* Another has populated it */
+ pte_lock_deinit(new);
+ pte_free(new);
+ } else {
+ mm->nr_ptes++;
inc_page_state(nr_page_table_pages);
pmd_populate(mm, pmd, new);
}
-out:
- return pte_offset_map(pmd, address);
+ spin_unlock(&mm->page_table_lock);
+ return 0;
}
-pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
+int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
{
- if (!pmd_present(*pmd)) {
- pte_t *new;
+ pte_t *new = pte_alloc_one_kernel(&init_mm, address);
+ if (!new)
+ return -ENOMEM;
+
+ spin_lock(&init_mm.page_table_lock);
+ if (pmd_present(*pmd)) /* Another has populated it */
+ pte_free_kernel(new);
+ else
+ pmd_populate_kernel(&init_mm, pmd, new);
+ spin_unlock(&init_mm.page_table_lock);
+ return 0;
+}
- spin_unlock(&mm->page_table_lock);
- new = pte_alloc_one_kernel(mm, address);
- spin_lock(&mm->page_table_lock);
- if (!new)
+static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
+{
+ if (file_rss)
+ add_mm_counter(mm, file_rss, file_rss);
+ if (anon_rss)
+ add_mm_counter(mm, anon_rss, anon_rss);
+}
+
+/*
+ * This function is called to print an error when a bad pte
+ * is found. For example, we might have a PFN-mapped pte in
+ * a region that doesn't allow it.
+ *
+ * The calling function must still handle the error.
+ */
+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);
+ dump_stack();
+}
+
+static inline int is_cow_mapping(unsigned int flags)
+{
+ return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
+}
+
+/*
+ * This function gets the "struct page" associated with a pte.
+ *
+ * NOTE! Some mappings do not have "struct pages". A raw PFN mapping
+ * will have each page table entry just pointing to a raw page frame
+ * number, and as far as the VM layer is concerned, those do not have
+ * pages associated with them - even if the PFN might point to memory
+ * that otherwise is perfectly fine and has a "struct page".
+ *
+ * The way we recognize those mappings is through the rules set up
+ * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set,
+ * and the vm_pgoff will point to the first PFN mapped: thus every
+ * page that is a raw mapping will always honor the rule
+ *
+ * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
+ *
+ * and if that isn't true, the page has been COW'ed (in which case it
+ * _does_ have a "struct page" associated with it even if it is in a
+ * VM_PFNMAP range).
+ */
+struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
+{
+ unsigned long pfn = pte_pfn(pte);
+
+ if (unlikely(vma->vm_flags & VM_PFNMAP)) {
+ unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT;
+ if (pfn == vma->vm_pgoff + off)
return NULL;
+ if (!is_cow_mapping(vma->vm_flags))
+ return NULL;
+ }
- /*
- * Because we dropped the lock, we should re-check the
- * entry, as somebody else could have populated it..
- */
- if (pmd_present(*pmd)) {
- pte_free_kernel(new);
- goto out;
- }
- pmd_populate_kernel(mm, pmd, new);
+ /*
+ * Add some anal sanity checks for now. Eventually,
+ * we should just do "return pfn_to_page(pfn)", but
+ * in the meantime we check that we get a valid pfn,
+ * and that the resulting page looks ok.
+ */
+ if (unlikely(!pfn_valid(pfn))) {
+ if (!(vma->vm_flags & VM_RESERVED))
+ print_bad_pte(vma, pte, addr);
+ return NULL;
}
-out:
- return pte_offset_kernel(pmd, address);
+
+ /*
+ * NOTE! We still have PageReserved() pages in the page
+ * tables.
+ *
+ * The PAGE_ZERO() pages and various VDSO mappings can
+ * cause them to exist.
+ */
+ return pfn_to_page(pfn);
}
-#define PTE_TABLE_MASK ((PTRS_PER_PTE-1) * sizeof(pte_t))
-#define PMD_TABLE_MASK ((PTRS_PER_PMD-1) * sizeof(pmd_t))
/*
* copy one vm_area from one task to the other. Assumes the page tables
* already present in the new task to be cleared in the whole range
* covered by this vma.
- *
- * 08Jan98 Merged into one routine from several inline routines to reduce
- * variable count and make things faster. -jj
- *
- * dst->page_table_lock is held on entry and exit,
- * but may be dropped within pmd_alloc() and pte_alloc_map().
*/
-int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
- struct vm_area_struct *vma)
+
+static inline void
+copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+ pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
+ unsigned long addr, int *rss)
{
- pgd_t * src_pgd, * dst_pgd;
- unsigned long address = vma->vm_start;
- unsigned long end = vma->vm_end;
- unsigned long cow;
+ unsigned long vm_flags = vma->vm_flags;
+ pte_t pte = *src_pte;
+ struct page *page;
- if (is_vm_hugetlb_page(vma))
- return copy_hugetlb_page_range(dst, src, vma);
+ /* pte contains position in swap or file, so copy. */
+ if (unlikely(!pte_present(pte))) {
+ if (!pte_file(pte)) {
+ swap_duplicate(pte_to_swp_entry(pte));
+ /* make sure dst_mm is on swapoff's mmlist. */
+ if (unlikely(list_empty(&dst_mm->mmlist))) {
+ spin_lock(&mmlist_lock);
+ if (list_empty(&dst_mm->mmlist))
+ list_add(&dst_mm->mmlist,
+ &src_mm->mmlist);
+ spin_unlock(&mmlist_lock);
+ }
+ }
+ goto out_set_pte;
+ }
- cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
- src_pgd = pgd_offset(src, address)-1;
- dst_pgd = pgd_offset(dst, address)-1;
+ /*
+ * If it's a COW mapping, write protect it both
+ * in the parent and the child
+ */
+ if (is_cow_mapping(vm_flags)) {
+ ptep_set_wrprotect(src_mm, addr, src_pte);
+ pte = *src_pte;
+ }
- for (;;) {
- pmd_t * src_pmd, * dst_pmd;
+ /*
+ * If it's a shared mapping, mark it clean in
+ * the child
+ */
+ if (vm_flags & VM_SHARED)
+ pte = pte_mkclean(pte);
+ pte = pte_mkold(pte);
+
+ page = vm_normal_page(vma, addr, pte);
+ if (page) {
+ get_page(page);
+ page_dup_rmap(page);
+ rss[!!PageAnon(page)]++;
+ }
- src_pgd++; dst_pgd++;
-
- /* copy_pmd_range */
-
- if (pgd_none(*src_pgd))
- goto skip_copy_pmd_range;
- if (unlikely(pgd_bad(*src_pgd))) {
- pgd_ERROR(*src_pgd);
- pgd_clear(src_pgd);
-skip_copy_pmd_range: address = (address + PGDIR_SIZE) & PGDIR_MASK;
- if (!address || (address >= end))
- goto out;
+out_set_pte:
+ set_pte_at(dst_mm, addr, dst_pte, pte);
+}
+
+static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+ pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end)
+{
+ pte_t *src_pte, *dst_pte;
+ spinlock_t *src_ptl, *dst_ptl;
+ int progress = 0;
+ int rss[2];
+
+again:
+ rss[1] = rss[0] = 0;
+ dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
+ if (!dst_pte)
+ return -ENOMEM;
+ src_pte = pte_offset_map_nested(src_pmd, addr);
+ src_ptl = pte_lockptr(src_mm, src_pmd);
+ spin_lock(src_ptl);
+
+ do {
+ /*
+ * We are holding two locks at this point - either of them
+ * could generate latencies in another task on another CPU.
+ */
+ if (progress >= 32) {
+ progress = 0;
+ if (need_resched() ||
+ need_lockbreak(src_ptl) ||
+ need_lockbreak(dst_ptl))
+ break;
+ }
+ if (pte_none(*src_pte)) {
+ progress++;
continue;
}
+ copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
+ progress += 8;
+ } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
+
+ spin_unlock(src_ptl);
+ pte_unmap_nested(src_pte - 1);
+ add_mm_rss(dst_mm, rss[0], rss[1]);
+ pte_unmap_unlock(dst_pte - 1, dst_ptl);
+ cond_resched();
+ if (addr != end)
+ goto again;
+ return 0;
+}
- src_pmd = pmd_offset(src_pgd, address);
- dst_pmd = pmd_alloc(dst, dst_pgd, address);
- if (!dst_pmd)
- goto nomem;
+static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+ pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end)
+{
+ pmd_t *src_pmd, *dst_pmd;
+ unsigned long next;
- do {
- pte_t * src_pte, * dst_pte;
-
- /* copy_pte_range */
-
- if (pmd_none(*src_pmd))
- goto skip_copy_pte_range;
- if (unlikely(pmd_bad(*src_pmd))) {
- pmd_ERROR(*src_pmd);
- pmd_clear(src_pmd);
-skip_copy_pte_range:
- address = (address + PMD_SIZE) & PMD_MASK;
- if (address >= end)
- goto out;
- goto cont_copy_pmd_range;
- }
+ dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
+ if (!dst_pmd)
+ return -ENOMEM;
+ src_pmd = pmd_offset(src_pud, addr);
+ do {
+ next = pmd_addr_end(addr, end);
+ if (pmd_none_or_clear_bad(src_pmd))
+ continue;
+ if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
+ vma, addr, next))
+ return -ENOMEM;
+ } while (dst_pmd++, src_pmd++, addr = next, addr != end);
+ return 0;
+}
- dst_pte = pte_alloc_map(dst, dst_pmd, address);
- if (!dst_pte)
- goto nomem;
- spin_lock(&src->page_table_lock);
- src_pte = pte_offset_map_nested(src_pmd, address);
- do {
- pte_t pte = *src_pte;
- struct page *page;
- unsigned long pfn;
-
- if (!vx_rsspages_avail(dst, 1)) {
- spin_unlock(&src->page_table_lock);
- goto nomem;
- }
- /* copy_one_pte */
-
- if (pte_none(pte))
- goto cont_copy_pte_range_noset;
- /* pte contains position in swap, so copy. */
- if (!pte_present(pte)) {
- if (!pte_file(pte))
- swap_duplicate(pte_to_swp_entry(pte));
- set_pte(dst_pte, pte);
- goto cont_copy_pte_range_noset;
- }
- pfn = pte_pfn(pte);
- /* the pte points outside of valid memory, the
- * mapping is assumed to be good, meaningful
- * and not mapped via rmap - duplicate the
- * mapping as is.
- */
- page = NULL;
- if (pfn_valid(pfn))
- page = pfn_to_page(pfn);
+static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+ pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end)
+{
+ pud_t *src_pud, *dst_pud;
+ unsigned long next;
- if (!page || PageReserved(page)) {
- set_pte(dst_pte, pte);
- goto cont_copy_pte_range_noset;
- }
+ dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
+ if (!dst_pud)
+ return -ENOMEM;
+ src_pud = pud_offset(src_pgd, addr);
+ do {
+ next = pud_addr_end(addr, end);
+ if (pud_none_or_clear_bad(src_pud))
+ continue;
+ if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
+ vma, addr, next))
+ return -ENOMEM;
+ } while (dst_pud++, src_pud++, addr = next, addr != end);
+ return 0;
+}
- /*
- * If it's a COW mapping, write protect it both
- * in the parent and the child
- */
- if (cow) {
- ptep_set_wrprotect(src_pte);
- pte = *src_pte;
- }
+int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+ struct vm_area_struct *vma)
+{
+ pgd_t *src_pgd, *dst_pgd;
+ unsigned long next;
+ unsigned long addr = vma->vm_start;
+ unsigned long end = vma->vm_end;
- /*
- * If it's a shared mapping, mark it clean in
- * the child
- */
- if (vma->vm_flags & VM_SHARED)
- pte = pte_mkclean(pte);
- pte = pte_mkold(pte);
- get_page(page);
- // dst->rss++;
- vx_rsspages_inc(dst);
- set_pte(dst_pte, pte);
- page_dup_rmap(page);
-cont_copy_pte_range_noset:
- address += PAGE_SIZE;
- if (address >= end) {
- pte_unmap_nested(src_pte);
- pte_unmap(dst_pte);
- goto out_unlock;
- }
- src_pte++;
- dst_pte++;
- } while ((unsigned long)src_pte & PTE_TABLE_MASK);
- pte_unmap_nested(src_pte-1);
- pte_unmap(dst_pte-1);
- spin_unlock(&src->page_table_lock);
- cond_resched_lock(&dst->page_table_lock);
-cont_copy_pmd_range:
- src_pmd++;
- dst_pmd++;
- } while ((unsigned long)src_pmd & PMD_TABLE_MASK);
+ /*
+ * Don't copy ptes where a page fault will fill them correctly.
+ * Fork becomes much lighter when there are big shared or private
+ * readonly mappings. The tradeoff is that copy_page_range is more
+ * efficient than faulting.
+ */
+ if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
+ if (!vma->anon_vma)
+ return 0;
}
-out_unlock:
- spin_unlock(&src->page_table_lock);
-out:
+
+ if (is_vm_hugetlb_page(vma))
+ return copy_hugetlb_page_range(dst_mm, src_mm, vma);
+
+ dst_pgd = pgd_offset(dst_mm, addr);
+ src_pgd = pgd_offset(src_mm, addr);
+ do {
+ next = pgd_addr_end(addr, end);
+ if (pgd_none_or_clear_bad(src_pgd))
+ continue;
+ if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
+ vma, addr, next))
+ return -ENOMEM;
+ } while (dst_pgd++, src_pgd++, addr = next, addr != end);
return 0;
-nomem:
- return -ENOMEM;
}
-static void zap_pte_range(struct mmu_gather *tlb,
- pmd_t *pmd, unsigned long address,
- unsigned long size, struct zap_details *details)
+static unsigned long zap_pte_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, pmd_t *pmd,
+ unsigned long addr, unsigned long end,
+ long *zap_work, struct zap_details *details)
{
- unsigned long offset;
- pte_t *ptep;
+ struct mm_struct *mm = tlb->mm;
+ pte_t *pte;
+ spinlock_t *ptl;
+ int file_rss = 0;
+ int anon_rss = 0;
- if (pmd_none(*pmd))
- return;
- if (unlikely(pmd_bad(*pmd))) {
- pmd_ERROR(*pmd);
- pmd_clear(pmd);
- return;
- }
- ptep = pte_offset_map(pmd, address);
- offset = address & ~PMD_MASK;
- if (offset + size > PMD_SIZE)
- size = PMD_SIZE - offset;
- size &= PAGE_MASK;
- if (details && !details->check_mapping && !details->nonlinear_vma)
- details = NULL;
- for (offset=0; offset < size; ptep++, offset += PAGE_SIZE) {
- pte_t pte = *ptep;
- if (pte_none(pte))
+ pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+ do {
+ pte_t ptent = *pte;
+ if (pte_none(ptent)) {
+ (*zap_work)--;
continue;
- if (pte_present(pte)) {
- struct page *page = NULL;
- unsigned long pfn = pte_pfn(pte);
- if (pfn_valid(pfn)) {
- page = pfn_to_page(pfn);
- if (PageReserved(page))
- page = NULL;
- }
+ }
+
+ (*zap_work) -= PAGE_SIZE;
+
+ if (pte_present(ptent)) {
+ struct page *page;
+
+ page = vm_normal_page(vma, addr, ptent);
if (unlikely(details) && page) {
/*
* unmap_shared_mapping_pages() wants to
page->index > details->last_index))
continue;
}
- pte = ptep_get_and_clear(ptep);
- tlb_remove_tlb_entry(tlb, ptep, address+offset);
+ ptent = ptep_get_and_clear_full(mm, addr, pte,
+ tlb->fullmm);
+ tlb_remove_tlb_entry(tlb, pte, addr);
if (unlikely(!page))
continue;
if (unlikely(details) && details->nonlinear_vma
&& linear_page_index(details->nonlinear_vma,
- address+offset) != page->index)
- set_pte(ptep, pgoff_to_pte(page->index));
- if (pte_dirty(pte))
- set_page_dirty(page);
- if (pte_young(pte) && !PageAnon(page))
- mark_page_accessed(page);
- tlb->freed++;
+ addr) != page->index)
+ set_pte_at(mm, addr, pte,
+ pgoff_to_pte(page->index));
+ if (PageAnon(page))
+ anon_rss--;
+ else {
+ if (pte_dirty(ptent))
+ set_page_dirty(page);
+ if (pte_young(ptent))
+ mark_page_accessed(page);
+ file_rss--;
+ }
page_remove_rmap(page);
tlb_remove_page(tlb, page);
continue;
*/
if (unlikely(details))
continue;
- if (!pte_file(pte))
- free_swap_and_cache(pte_to_swp_entry(pte));
- pte_clear(ptep);
- }
- pte_unmap(ptep-1);
+ if (!pte_file(ptent))
+ free_swap_and_cache(pte_to_swp_entry(ptent));
+ pte_clear_full(mm, addr, pte, tlb->fullmm);
+ } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
+
+ add_mm_rss(mm, file_rss, anon_rss);
+ pte_unmap_unlock(pte - 1, ptl);
+
+ return addr;
}
-static void zap_pmd_range(struct mmu_gather *tlb,
- pgd_t * dir, unsigned long address,
- unsigned long size, struct zap_details *details)
+static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, pud_t *pud,
+ unsigned long addr, unsigned long end,
+ long *zap_work, struct zap_details *details)
{
- pmd_t * pmd;
- unsigned long end;
+ pmd_t *pmd;
+ unsigned long next;
- if (pgd_none(*dir))
- return;
- if (unlikely(pgd_bad(*dir))) {
- pgd_ERROR(*dir);
- pgd_clear(dir);
- return;
- }
- pmd = pmd_offset(dir, address);
- end = address + size;
- if (end > ((address + PGDIR_SIZE) & PGDIR_MASK))
- end = ((address + PGDIR_SIZE) & PGDIR_MASK);
+ pmd = pmd_offset(pud, addr);
do {
- zap_pte_range(tlb, pmd, address, end - address, details);
- address = (address + PMD_SIZE) & PMD_MASK;
- pmd++;
- } while (address && (address < end));
+ next = pmd_addr_end(addr, end);
+ if (pmd_none_or_clear_bad(pmd)) {
+ (*zap_work)--;
+ continue;
+ }
+ next = zap_pte_range(tlb, vma, pmd, addr, next,
+ zap_work, details);
+ } while (pmd++, addr = next, (addr != end && *zap_work > 0));
+
+ return addr;
}
-static void unmap_page_range(struct mmu_gather *tlb,
- struct vm_area_struct *vma, unsigned long address,
- unsigned long end, struct zap_details *details)
+static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, pgd_t *pgd,
+ unsigned long addr, unsigned long end,
+ long *zap_work, struct zap_details *details)
{
- pgd_t * dir;
+ pud_t *pud;
+ unsigned long next;
- BUG_ON(address >= end);
- dir = pgd_offset(vma->vm_mm, address);
- tlb_start_vma(tlb, vma);
+ pud = pud_offset(pgd, addr);
do {
- zap_pmd_range(tlb, dir, address, end - address, details);
- address = (address + PGDIR_SIZE) & PGDIR_MASK;
- dir++;
- } while (address && (address < end));
- tlb_end_vma(tlb, vma);
+ next = pud_addr_end(addr, end);
+ if (pud_none_or_clear_bad(pud)) {
+ (*zap_work)--;
+ continue;
+ }
+ next = zap_pmd_range(tlb, vma, pud, addr, next,
+ zap_work, details);
+ } while (pud++, addr = next, (addr != end && *zap_work > 0));
+
+ return addr;
}
-/* Dispose of an entire struct mmu_gather per rescheduling point */
-#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
-#define ZAP_BLOCK_SIZE (FREE_PTE_NR * PAGE_SIZE)
-#endif
+static unsigned long unmap_page_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end,
+ long *zap_work, struct zap_details *details)
+{
+ pgd_t *pgd;
+ unsigned long next;
-/* For UP, 256 pages at a time gives nice low latency */
-#if !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
-#define ZAP_BLOCK_SIZE (256 * PAGE_SIZE)
-#endif
+ if (details && !details->check_mapping && !details->nonlinear_vma)
+ details = NULL;
+
+ BUG_ON(addr >= end);
+ tlb_start_vma(tlb, vma);
+ pgd = pgd_offset(vma->vm_mm, addr);
+ do {
+ next = pgd_addr_end(addr, end);
+ if (pgd_none_or_clear_bad(pgd)) {
+ (*zap_work)--;
+ continue;
+ }
+ next = zap_pud_range(tlb, vma, pgd, addr, next,
+ zap_work, details);
+ } while (pgd++, addr = next, (addr != end && *zap_work > 0));
+ tlb_end_vma(tlb, vma);
+
+ return addr;
+}
+#ifdef CONFIG_PREEMPT
+# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
+#else
/* No preempt: go for improved straight-line efficiency */
-#if !defined(CONFIG_PREEMPT)
-#define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
+# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
#endif
/**
* unmap_vmas - unmap a range of memory covered by a list of vma's
* @tlbp: address of the caller's struct mmu_gather
- * @mm: the controlling mm_struct
* @vma: the starting vma
* @start_addr: virtual address at which to start unmapping
* @end_addr: virtual address at which to end unmapping
* @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
* @details: details of nonlinear truncation or shared cache invalidation
*
- * Returns the number of vma's which were covered by the unmapping.
+ * Returns the end address of the unmapping (restart addr if interrupted).
*
- * Unmap all pages in the vma list. Called under page_table_lock.
+ * Unmap all pages in the vma list.
*
- * We aim to not hold page_table_lock for too long (for scheduling latency
- * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
+ * We aim to not hold locks for too long (for scheduling latency reasons).
+ * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
* return the ending mmu_gather to the caller.
*
* Only addresses between `start' and `end' will be unmapped.
* ensure that any thus-far unmapped pages are flushed before unmap_vmas()
* drops the lock and schedules.
*/
-int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
+unsigned long unmap_vmas(struct mmu_gather **tlbp,
struct vm_area_struct *vma, unsigned long start_addr,
unsigned long end_addr, unsigned long *nr_accounted,
struct zap_details *details)
{
- unsigned long zap_bytes = ZAP_BLOCK_SIZE;
+ long zap_work = ZAP_BLOCK_SIZE;
unsigned long tlb_start = 0; /* For tlb_finish_mmu */
int tlb_start_valid = 0;
- int ret = 0;
- int atomic = details && details->atomic;
+ unsigned long start = start_addr;
+ spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
+ int fullmm = (*tlbp)->fullmm;
for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
- unsigned long start;
unsigned long end;
start = max(vma->vm_start, start_addr);
if (vma->vm_flags & VM_ACCOUNT)
*nr_accounted += (end - start) >> PAGE_SHIFT;
- ret++;
while (start != end) {
- unsigned long block;
-
if (!tlb_start_valid) {
tlb_start = start;
tlb_start_valid = 1;
}
- if (is_vm_hugetlb_page(vma)) {
- block = end - start;
+ if (unlikely(is_vm_hugetlb_page(vma))) {
unmap_hugepage_range(vma, start, end);
- } else {
- block = min(zap_bytes, end - start);
- unmap_page_range(*tlbp, vma, start,
- start + block, details);
+ zap_work -= (end - start) /
+ (HPAGE_SIZE / PAGE_SIZE);
+ start = end;
+ } else
+ start = unmap_page_range(*tlbp, vma,
+ start, end, &zap_work, details);
+
+ if (zap_work > 0) {
+ BUG_ON(start != end);
+ break;
}
- start += block;
- zap_bytes -= block;
- if ((long)zap_bytes > 0)
- continue;
- if (!atomic && need_resched()) {
- int fullmm = tlb_is_full_mm(*tlbp);
- tlb_finish_mmu(*tlbp, tlb_start, start);
- cond_resched_lock(&mm->page_table_lock);
- *tlbp = tlb_gather_mmu(mm, fullmm);
- tlb_start_valid = 0;
+ tlb_finish_mmu(*tlbp, tlb_start, start);
+
+ if (need_resched() ||
+ (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
+ if (i_mmap_lock) {
+ *tlbp = NULL;
+ goto out;
+ }
+ cond_resched();
}
- zap_bytes = ZAP_BLOCK_SIZE;
+
+ *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
+ tlb_start_valid = 0;
+ zap_work = ZAP_BLOCK_SIZE;
}
}
- return ret;
+out:
+ return start; /* which is now the end (or restart) address */
}
/**
* @size: number of bytes to zap
* @details: details of nonlinear truncation or shared cache invalidation
*/
-void zap_page_range(struct vm_area_struct *vma, unsigned long address,
+unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
unsigned long size, struct zap_details *details)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long end = address + size;
unsigned long nr_accounted = 0;
- if (is_vm_hugetlb_page(vma)) {
- zap_hugepage_range(vma, address, size);
- return;
- }
-
lru_add_drain();
- spin_lock(&mm->page_table_lock);
tlb = tlb_gather_mmu(mm, 0);
- unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details);
- tlb_finish_mmu(tlb, address, end);
- spin_unlock(&mm->page_table_lock);
+ update_hiwater_rss(mm);
+ end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
+ if (tlb)
+ tlb_finish_mmu(tlb, address, end);
+ return end;
}
/*
* Do a quick page-table lookup for a single page.
- * mm->page_table_lock must be held.
*/
-struct page *
-follow_page(struct mm_struct *mm, unsigned long address, int write)
+struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
+ unsigned int flags)
{
pgd_t *pgd;
+ pud_t *pud;
pmd_t *pmd;
pte_t *ptep, pte;
- unsigned long pfn;
+ spinlock_t *ptl;
struct page *page;
+ struct mm_struct *mm = vma->vm_mm;
- page = follow_huge_addr(mm, address, write);
- if (! IS_ERR(page))
- return page;
+ page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
+ if (!IS_ERR(page)) {
+ BUG_ON(flags & FOLL_GET);
+ goto out;
+ }
+ page = NULL;
pgd = pgd_offset(mm, address);
if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
- goto out;
+ goto no_page_table;
- pmd = pmd_offset(pgd, address);
- if (pmd_none(*pmd))
- goto out;
- if (pmd_huge(*pmd))
- return follow_huge_pmd(mm, address, pmd, write);
- if (unlikely(pmd_bad(*pmd)))
+ pud = pud_offset(pgd, address);
+ if (pud_none(*pud) || unlikely(pud_bad(*pud)))
+ goto no_page_table;
+
+ pmd = pmd_offset(pud, address);
+ if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
+ goto no_page_table;
+
+ if (pmd_huge(*pmd)) {
+ BUG_ON(flags & FOLL_GET);
+ page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
goto out;
+ }
- ptep = pte_offset_map(pmd, address);
+ ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
if (!ptep)
goto out;
pte = *ptep;
- pte_unmap(ptep);
- if (pte_present(pte)) {
- if (write && !pte_write(pte))
- goto out;
- pfn = pte_pfn(pte);
- if (pfn_valid(pfn)) {
- page = pfn_to_page(pfn);
- if (write && !pte_dirty(pte) && !PageDirty(page))
- set_page_dirty(page);
- mark_page_accessed(page);
- return page;
- }
+ if (!pte_present(pte))
+ goto unlock;
+ if ((flags & FOLL_WRITE) && !pte_write(pte))
+ goto unlock;
+ page = vm_normal_page(vma, address, pte);
+ if (unlikely(!page))
+ goto unlock;
+
+ if (flags & FOLL_GET)
+ get_page(page);
+ if (flags & FOLL_TOUCH) {
+ if ((flags & FOLL_WRITE) &&
+ !pte_dirty(pte) && !PageDirty(page))
+ set_page_dirty(page);
+ mark_page_accessed(page);
}
-
+unlock:
+ pte_unmap_unlock(ptep, ptl);
out:
- return NULL;
-}
-
-/*
- * Given a physical address, is there a useful struct page pointing to
- * it? This may become more complex in the future if we start dealing
- * with IO-aperture pages for direct-IO.
- */
-
-static inline struct page *get_page_map(struct page *page)
-{
- if (!pfn_valid(page_to_pfn(page)))
- return NULL;
return page;
-}
-
-
-static inline int
-untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma,
- unsigned long address)
-{
- pgd_t *pgd;
- pmd_t *pmd;
-
- /* Check if the vma is for an anonymous mapping. */
- if (vma->vm_ops && vma->vm_ops->nopage)
- return 0;
-
- /* Check if page directory entry exists. */
- pgd = pgd_offset(mm, address);
- if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
- return 1;
-
- /* Check if page middle directory entry exists. */
- pmd = pmd_offset(pgd, address);
- if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
- return 1;
- /* There is a pte slot for 'address' in 'mm'. */
- return 0;
+no_page_table:
+ /*
+ * When core dumping an enormous anonymous area that nobody
+ * has touched so far, we don't want to allocate page tables.
+ */
+ if (flags & FOLL_ANON) {
+ page = ZERO_PAGE(address);
+ if (flags & FOLL_GET)
+ get_page(page);
+ BUG_ON(flags & FOLL_WRITE);
+ }
+ return page;
}
-
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, int len, int write, int force,
struct page **pages, struct vm_area_struct **vmas)
{
int i;
- unsigned int flags;
+ unsigned int vm_flags;
/*
* Require read or write permissions.
* If 'force' is set, we only require the "MAY" flags.
*/
- flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
- flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
+ vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
+ vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
i = 0;
do {
- struct vm_area_struct * vma;
+ struct vm_area_struct *vma;
+ unsigned int foll_flags;
vma = find_extend_vma(mm, start);
if (!vma && in_gate_area(tsk, start)) {
unsigned long pg = start & PAGE_MASK;
struct vm_area_struct *gate_vma = get_gate_vma(tsk);
pgd_t *pgd;
+ pud_t *pud;
pmd_t *pmd;
pte_t *pte;
if (write) /* user gate pages are read-only */
return i ? : -EFAULT;
- pgd = pgd_offset_gate(mm, pg);
- if (!pgd)
- return i ? : -EFAULT;
- pmd = pmd_offset(pgd, pg);
- if (!pmd)
+ if (pg > TASK_SIZE)
+ pgd = pgd_offset_k(pg);
+ else
+ pgd = pgd_offset_gate(mm, pg);
+ BUG_ON(pgd_none(*pgd));
+ pud = pud_offset(pgd, pg);
+ BUG_ON(pud_none(*pud));
+ pmd = pmd_offset(pud, pg);
+ if (pmd_none(*pmd))
return i ? : -EFAULT;
pte = pte_offset_map(pmd, pg);
- if (!pte)
- return i ? : -EFAULT;
- if (!pte_present(*pte)) {
+ if (pte_none(*pte)) {
pte_unmap(pte);
return i ? : -EFAULT;
}
if (pages) {
- pages[i] = pte_page(*pte);
- get_page(pages[i]);
+ struct page *page = vm_normal_page(gate_vma, start, *pte);
+ pages[i] = page;
+ if (page)
+ get_page(page);
}
pte_unmap(pte);
if (vmas)
continue;
}
- if (!vma || (pages && (vma->vm_flags & VM_IO))
- || !(flags & vma->vm_flags))
+#ifdef CONFIG_XEN
+ if (vma && (vma->vm_flags & VM_FOREIGN)) {
+ struct page **map = vma->vm_private_data;
+ int offset = (start - vma->vm_start) >> PAGE_SHIFT;
+ if (map[offset] != NULL) {
+ if (pages) {
+ struct page *page = map[offset];
+
+ pages[i] = page;
+ get_page(page);
+ }
+ if (vmas)
+ vmas[i] = vma;
+ i++;
+ start += PAGE_SIZE;
+ len--;
+ continue;
+ }
+ }
+#endif
+ if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
+ || !(vm_flags & vma->vm_flags))
return i ? : -EFAULT;
if (is_vm_hugetlb_page(vma)) {
&start, &len, i);
continue;
}
- spin_lock(&mm->page_table_lock);
+
+ foll_flags = FOLL_TOUCH;
+ if (pages)
+ foll_flags |= FOLL_GET;
+ if (!write && !(vma->vm_flags & VM_LOCKED) &&
+ (!vma->vm_ops || !vma->vm_ops->nopage))
+ foll_flags |= FOLL_ANON;
+
do {
- struct page *map;
- int lookup_write = write;
- while (!(map = follow_page(mm, start, lookup_write))) {
+ struct page *page;
+
+ 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);
/*
- * Shortcut for anonymous pages. We don't want
- * to force the creation of pages tables for
- * insanly big anonymously mapped areas that
- * nobody touched so far. This is important
- * for doing a core dump for these mappings.
+ * The VM_FAULT_WRITE bit tells us that do_wp_page has
+ * broken COW when necessary, even if maybe_mkwrite
+ * decided not to set pte_write. We can thus safely do
+ * subsequent page lookups as if they were reads.
*/
- if (!lookup_write &&
- untouched_anonymous_page(mm,vma,start)) {
- map = ZERO_PAGE(start);
- break;
- }
- spin_unlock(&mm->page_table_lock);
- switch (handle_mm_fault(mm,vma,start,write)) {
+ if (ret & VM_FAULT_WRITE)
+ foll_flags &= ~FOLL_WRITE;
+
+ switch (ret & ~VM_FAULT_WRITE) {
case VM_FAULT_MINOR:
tsk->min_flt++;
break;
default:
BUG();
}
- /*
- * Now that we have performed a write fault
- * and surely no longer have a shared page we
- * shouldn't write, we shouldn't ignore an
- * unwritable page in the page table if
- * we are forcing write access.
- */
- lookup_write = write && !force;
- spin_lock(&mm->page_table_lock);
}
if (pages) {
- pages[i] = get_page_map(map);
- if (!pages[i]) {
- spin_unlock(&mm->page_table_lock);
- while (i--)
- page_cache_release(pages[i]);
- i = -EFAULT;
- goto out;
- }
- flush_dcache_page(pages[i]);
- if (!PageReserved(pages[i]))
- page_cache_get(pages[i]);
+ pages[i] = page;
+
+ flush_anon_page(page, start);
+ flush_dcache_page(page);
}
if (vmas)
vmas[i] = vma;
i++;
start += PAGE_SIZE;
len--;
- } while(len && start < vma->vm_end);
- spin_unlock(&mm->page_table_lock);
- } while(len);
-out:
+ } while (len && start < vma->vm_end);
+ } while (len);
return i;
}
-
EXPORT_SYMBOL(get_user_pages);
-static void zeromap_pte_range(pte_t * pte, unsigned long address,
- unsigned long size, pgprot_t prot)
+static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
+ unsigned long addr, unsigned long end, pgprot_t prot)
{
- unsigned long end;
+ pte_t *pte;
+ spinlock_t *ptl;
- address &= ~PMD_MASK;
- end = address + size;
- if (end > PMD_SIZE)
- end = PMD_SIZE;
+ pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
+ if (!pte)
+ return -ENOMEM;
do {
- pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(address), prot));
+ struct page *page = ZERO_PAGE(addr);
+ pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
+ page_cache_get(page);
+ page_add_file_rmap(page);
+ inc_mm_counter(mm, file_rss);
BUG_ON(!pte_none(*pte));
- set_pte(pte, zero_pte);
- address += PAGE_SIZE;
- pte++;
- } while (address && (address < end));
+ set_pte_at(mm, addr, pte, zero_pte);
+ } while (pte++, addr += PAGE_SIZE, addr != end);
+ pte_unmap_unlock(pte - 1, ptl);
+ return 0;
}
-static inline int zeromap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address,
- unsigned long size, pgprot_t prot)
+static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
+ unsigned long addr, unsigned long end, pgprot_t prot)
{
- unsigned long base, end;
+ pmd_t *pmd;
+ unsigned long next;
- base = address & PGDIR_MASK;
- address &= ~PGDIR_MASK;
- end = address + size;
- if (end > PGDIR_SIZE)
- end = PGDIR_SIZE;
+ pmd = pmd_alloc(mm, pud, addr);
+ if (!pmd)
+ return -ENOMEM;
do {
- pte_t * pte = pte_alloc_map(mm, pmd, base + address);
- if (!pte)
+ next = pmd_addr_end(addr, end);
+ if (zeromap_pte_range(mm, pmd, addr, next, prot))
return -ENOMEM;
- zeromap_pte_range(pte, base + address, end - address, prot);
- pte_unmap(pte);
- address = (address + PMD_SIZE) & PMD_MASK;
- pmd++;
- } while (address && (address < end));
+ } while (pmd++, addr = next, addr != end);
return 0;
}
-int zeromap_page_range(struct vm_area_struct *vma, unsigned long address, unsigned long size, pgprot_t prot)
+static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
+ unsigned long addr, unsigned long end, pgprot_t prot)
{
- int error = 0;
- pgd_t * dir;
- unsigned long beg = address;
- unsigned long end = address + size;
- struct mm_struct *mm = vma->vm_mm;
+ pud_t *pud;
+ unsigned long next;
- dir = pgd_offset(mm, address);
- flush_cache_range(vma, beg, end);
- if (address >= end)
- BUG();
+ pud = pud_alloc(mm, pgd, addr);
+ if (!pud)
+ return -ENOMEM;
+ do {
+ next = pud_addr_end(addr, end);
+ if (zeromap_pmd_range(mm, pud, addr, next, prot))
+ return -ENOMEM;
+ } while (pud++, addr = next, addr != end);
+ return 0;
+}
- spin_lock(&mm->page_table_lock);
+int zeromap_page_range(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long size, pgprot_t prot)
+{
+ pgd_t *pgd;
+ unsigned long next;
+ unsigned long end = addr + size;
+ struct mm_struct *mm = vma->vm_mm;
+ int err;
+
+ BUG_ON(addr >= end);
+ pgd = pgd_offset(mm, addr);
+ flush_cache_range(vma, addr, end);
do {
- pmd_t *pmd = pmd_alloc(mm, dir, address);
- error = -ENOMEM;
- if (!pmd)
- break;
- error = zeromap_pmd_range(mm, pmd, address, end - address, prot);
- if (error)
+ next = pgd_addr_end(addr, end);
+ err = zeromap_pud_range(mm, pgd, addr, next, prot);
+ if (err)
break;
- address = (address + PGDIR_SIZE) & PGDIR_MASK;
- dir++;
- } while (address && (address < end));
- /*
- * Why flush? zeromap_pte_range has a BUG_ON for !pte_none()
- */
- flush_tlb_range(vma, beg, end);
- spin_unlock(&mm->page_table_lock);
- return error;
+ } while (pgd++, addr = next, addr != end);
+ return err;
}
+pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl)
+{
+ pgd_t * pgd = pgd_offset(mm, addr);
+ pud_t * pud = pud_alloc(mm, pgd, addr);
+ if (pud) {
+ pmd_t * pmd = pmd_alloc(mm, pud, addr);
+ if (pmd)
+ return pte_alloc_map_lock(mm, pmd, addr, ptl);
+ }
+ return NULL;
+}
+
+/*
+ * This is the old fallback for page remapping.
+ *
+ * For historical reasons, it only allows reserved pages. Only
+ * old drivers should use this, and they needed to mark their
+ * pages reserved for the old functions anyway.
+ */
+static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot)
+{
+ int retval;
+ pte_t *pte;
+ spinlock_t *ptl;
+
+ retval = -EINVAL;
+ if (PageAnon(page))
+ goto out;
+ retval = -ENOMEM;
+ flush_dcache_page(page);
+ pte = get_locked_pte(mm, addr, &ptl);
+ if (!pte)
+ goto out;
+ retval = -EBUSY;
+ if (!pte_none(*pte))
+ goto out_unlock;
+
+ /* Ok, finally just insert the thing.. */
+ get_page(page);
+ inc_mm_counter(mm, file_rss);
+ page_add_file_rmap(page);
+ set_pte_at(mm, addr, pte, mk_pte(page, prot));
+
+ retval = 0;
+out_unlock:
+ pte_unmap_unlock(pte, ptl);
+out:
+ return retval;
+}
+
+/*
+ * This allows drivers to insert individual pages they've allocated
+ * into a user vma.
+ *
+ * The page has to be a nice clean _individual_ kernel allocation.
+ * If you allocate a compound page, you need to have marked it as
+ * such (__GFP_COMP), or manually just split the page up yourself
+ * (see split_page()).
+ *
+ * NOTE! Traditionally this was done with "remap_pfn_range()" which
+ * took an arbitrary page protection parameter. This doesn't allow
+ * that. Your vma protection will have to be set up correctly, which
+ * means that if you want a shared writable mapping, you'd better
+ * ask for a shared writable mapping!
+ *
+ * The page does not need to be reserved.
+ */
+int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page)
+{
+ if (addr < vma->vm_start || addr >= vma->vm_end)
+ return -EFAULT;
+ if (!page_count(page))
+ return -EINVAL;
+ vma->vm_flags |= VM_INSERTPAGE;
+ return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot);
+}
+EXPORT_SYMBOL(vm_insert_page);
+
/*
* maps a range of physical memory into the requested pages. the old
* mappings are removed. any references to nonexistent pages results
* in null mappings (currently treated as "copy-on-access")
*/
-static inline void remap_pte_range(pte_t * pte, unsigned long address, unsigned long size,
- unsigned long phys_addr, pgprot_t prot)
+static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
+ unsigned long addr, unsigned long end,
+ unsigned long pfn, pgprot_t prot)
{
- unsigned long end;
- unsigned long pfn;
+ pte_t *pte;
+ spinlock_t *ptl;
- address &= ~PMD_MASK;
- end = address + size;
- if (end > PMD_SIZE)
- end = PMD_SIZE;
- pfn = phys_addr >> PAGE_SHIFT;
+ pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
+ if (!pte)
+ return -ENOMEM;
do {
BUG_ON(!pte_none(*pte));
- if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn)))
- set_pte(pte, pfn_pte(pfn, prot));
- address += PAGE_SIZE;
+ set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
pfn++;
- pte++;
- } while (address && (address < end));
+ } while (pte++, addr += PAGE_SIZE, addr != end);
+ pte_unmap_unlock(pte - 1, ptl);
+ return 0;
}
-static inline int remap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address, unsigned long size,
- unsigned long phys_addr, pgprot_t prot)
+static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
+ unsigned long addr, unsigned long end,
+ unsigned long pfn, pgprot_t prot)
{
- unsigned long base, end;
+ pmd_t *pmd;
+ unsigned long next;
- base = address & PGDIR_MASK;
- address &= ~PGDIR_MASK;
- end = address + size;
- if (end > PGDIR_SIZE)
- end = PGDIR_SIZE;
- phys_addr -= address;
+ pfn -= addr >> PAGE_SHIFT;
+ pmd = pmd_alloc(mm, pud, addr);
+ if (!pmd)
+ return -ENOMEM;
do {
- pte_t * pte = pte_alloc_map(mm, pmd, base + address);
- if (!pte)
+ next = pmd_addr_end(addr, end);
+ if (remap_pte_range(mm, pmd, addr, next,
+ pfn + (addr >> PAGE_SHIFT), prot))
return -ENOMEM;
- remap_pte_range(pte, base + address, end - address, address + phys_addr, prot);
- pte_unmap(pte);
- address = (address + PMD_SIZE) & PMD_MASK;
- pmd++;
- } while (address && (address < end));
+ } while (pmd++, addr = next, addr != end);
+ return 0;
+}
+
+static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
+ unsigned long addr, unsigned long end,
+ unsigned long pfn, pgprot_t prot)
+{
+ pud_t *pud;
+ unsigned long next;
+
+ pfn -= addr >> PAGE_SHIFT;
+ pud = pud_alloc(mm, pgd, addr);
+ if (!pud)
+ return -ENOMEM;
+ do {
+ next = pud_addr_end(addr, end);
+ if (remap_pmd_range(mm, pud, addr, next,
+ pfn + (addr >> PAGE_SHIFT), prot))
+ return -ENOMEM;
+ } while (pud++, addr = next, addr != end);
return 0;
}
/* Note: this is only safe if the mm semaphore is held when called. */
-int remap_page_range(struct vm_area_struct *vma, unsigned long from, unsigned long phys_addr, unsigned long size, pgprot_t prot)
+int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long pfn, unsigned long size, pgprot_t prot)
{
- int error = 0;
- pgd_t * dir;
- unsigned long beg = from;
- unsigned long end = from + size;
+ pgd_t *pgd;
+ unsigned long next;
+ unsigned long end = addr + PAGE_ALIGN(size);
struct mm_struct *mm = vma->vm_mm;
+ int err;
+
+ /*
+ * Physically remapped pages are special. Tell the
+ * rest of the world about it:
+ * VM_IO tells people not to look at these pages
+ * (accesses can have side effects).
+ * VM_RESERVED is specified all over the place, because
+ * in 2.4 it kept swapout's vma scan off this vma; but
+ * in 2.6 the LRU scan won't even find its pages, so this
+ * flag means no more than count its pages in reserved_vm,
+ * and omit it from core dump, even when VM_IO turned off.
+ * VM_PFNMAP tells the core MM that the base pages are just
+ * raw PFN mappings, and do not have a "struct page" associated
+ * with them.
+ *
+ * There's a horrible special case to handle copy-on-write
+ * behaviour that some programs depend on. We mark the "original"
+ * un-COW'ed pages by matching them up with "vma->vm_pgoff".
+ */
+ if (is_cow_mapping(vma->vm_flags)) {
+ if (addr != vma->vm_start || end != vma->vm_end)
+ return -EINVAL;
+ vma->vm_pgoff = pfn;
+ }
+
+ vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
+
+ BUG_ON(addr >= end);
+ pfn -= addr >> PAGE_SHIFT;
+ pgd = pgd_offset(mm, addr);
+ flush_cache_range(vma, addr, end);
+ do {
+ next = pgd_addr_end(addr, end);
+ err = remap_pud_range(mm, pgd, addr, next,
+ pfn + (addr >> PAGE_SHIFT), prot);
+ if (err)
+ break;
+ } while (pgd++, addr = next, addr != end);
+ return err;
+}
+EXPORT_SYMBOL(remap_pfn_range);
+
+#ifdef CONFIG_XEN
+static inline int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
+ unsigned long addr, unsigned long end,
+ pte_fn_t fn, void *data)
+{
+ pte_t *pte;
+ int err;
+ struct page *pmd_page;
+ spinlock_t *ptl;
+
+ pte = (mm == &init_mm) ?
+ pte_alloc_kernel(pmd, addr) :
+ pte_alloc_map_lock(mm, pmd, addr, &ptl);
+ if (!pte)
+ return -ENOMEM;
+
+ BUG_ON(pmd_huge(*pmd));
- phys_addr -= from;
- dir = pgd_offset(mm, from);
- flush_cache_range(vma, beg, end);
- if (from >= end)
- BUG();
+ pmd_page = pmd_page(*pmd);
+
+ do {
+ err = fn(pte, pmd_page, addr, data);
+ if (err)
+ break;
+ } while (pte++, addr += PAGE_SIZE, addr != end);
+
+ if (mm != &init_mm)
+ pte_unmap_unlock(pte-1, ptl);
+ return err;
+}
+
+static inline int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
+ unsigned long addr, unsigned long end,
+ pte_fn_t fn, void *data)
+{
+ pmd_t *pmd;
+ unsigned long next;
+ int err;
+
+ pmd = pmd_alloc(mm, pud, addr);
+ if (!pmd)
+ return -ENOMEM;
+ do {
+ next = pmd_addr_end(addr, end);
+ err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
+ if (err)
+ break;
+ } while (pmd++, addr = next, addr != end);
+ return err;
+}
+
+static inline int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
+ unsigned long addr, unsigned long end,
+ pte_fn_t fn, void *data)
+{
+ pud_t *pud;
+ unsigned long next;
+ int err;
+
+ pud = pud_alloc(mm, pgd, addr);
+ if (!pud)
+ return -ENOMEM;
+ do {
+ next = pud_addr_end(addr, end);
+ err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
+ if (err)
+ break;
+ } while (pud++, addr = next, addr != end);
+ return err;
+}
+
+/*
+ * Scan a region of virtual memory, filling in page tables as necessary
+ * and calling a provided function on each leaf page table.
+ */
+int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
+ unsigned long size, pte_fn_t fn, void *data)
+{
+ pgd_t *pgd;
+ unsigned long next;
+ unsigned long end = addr + size;
+ int err;
- spin_lock(&mm->page_table_lock);
+ BUG_ON(addr >= end);
+ pgd = pgd_offset(mm, addr);
do {
- pmd_t *pmd = pmd_alloc(mm, dir, from);
- error = -ENOMEM;
- if (!pmd)
- break;
- error = remap_pmd_range(mm, pmd, from, end - from, phys_addr + from, prot);
- if (error)
+ next = pgd_addr_end(addr, end);
+ err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
+ if (err)
break;
- from = (from + PGDIR_SIZE) & PGDIR_MASK;
- dir++;
- } while (from && (from < end));
- /*
- * Why flush? remap_pte_range has a BUG_ON for !pte_none()
- */
- flush_tlb_range(vma, beg, end);
- spin_unlock(&mm->page_table_lock);
- return error;
+ } while (pgd++, addr = next, addr != end);
+ return err;
}
+EXPORT_SYMBOL_GPL(apply_to_page_range);
+#endif
-EXPORT_SYMBOL(remap_page_range);
+/*
+ * handle_pte_fault chooses page fault handler according to an entry
+ * which was read non-atomically. Before making any commitment, on
+ * those architectures or configurations (e.g. i386 with PAE) which
+ * might give a mix of unmatched parts, do_swap_page and do_file_page
+ * must check under lock before unmapping the pte and proceeding
+ * (but do_wp_page is only called after already making such a check;
+ * and do_anonymous_page and do_no_page can safely check later on).
+ */
+static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
+ pte_t *page_table, pte_t orig_pte)
+{
+ int same = 1;
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
+ if (sizeof(pte_t) > sizeof(unsigned long)) {
+ spinlock_t *ptl = pte_lockptr(mm, pmd);
+ spin_lock(ptl);
+ same = pte_same(*page_table, orig_pte);
+ spin_unlock(ptl);
+ }
+#endif
+ pte_unmap(page_table);
+ return same;
+}
/*
* Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
return pte;
}
-/*
- * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock
- */
-static inline void break_cow(struct vm_area_struct * vma, struct page * new_page, unsigned long address,
- pte_t *page_table)
+static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va)
{
- pte_t entry;
+ /*
+ * If the source page was a PFN mapping, we don't have
+ * a "struct page" for it. We do a best-effort copy by
+ * just copying from the original user address. If that
+ * fails, we just zero-fill it. Live with it.
+ */
+ if (unlikely(!src)) {
+ void *kaddr = kmap_atomic(dst, KM_USER0);
+ void __user *uaddr = (void __user *)(va & PAGE_MASK);
- flush_cache_page(vma, address);
- entry = maybe_mkwrite(pte_mkdirty(mk_pte(new_page, vma->vm_page_prot)),
- vma);
- ptep_establish(vma, address, page_table, entry);
- update_mmu_cache(vma, address, entry);
+ /*
+ * This really shouldn't fail, because the page is there
+ * in the page tables. But it might just be unreadable,
+ * in which case we just give up and fill the result with
+ * zeroes.
+ */
+ if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
+ memset(kaddr, 0, PAGE_SIZE);
+ kunmap_atomic(kaddr, KM_USER0);
+ return;
+
+ }
+ copy_user_highpage(dst, src, va);
}
/*
* to a shared page. It is done by copying the page to a new address
* and decrementing the shared-page counter for the old page.
*
- * Goto-purists beware: the only reason for goto's here is that it results
- * in better assembly code.. The "default" path will see no jumps at all.
- *
* Note that this routine assumes that the protection checks have been
* done by the caller (the low-level page fault routine in most cases).
* Thus we can safely just mark it writable once we've done any necessary
* change only once the write actually happens. This avoids a few races,
* and potentially makes it more efficient.
*
- * We hold the mm semaphore and the page_table_lock on entry and exit
- * with the page_table_lock released.
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), with pte both mapped and locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
-static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma,
- unsigned long address, pte_t *page_table, pmd_t *pmd, pte_t pte)
+static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, pte_t *page_table, pmd_t *pmd,
+ spinlock_t *ptl, pte_t orig_pte)
{
struct page *old_page, *new_page;
- unsigned long pfn = pte_pfn(pte);
pte_t entry;
+ int ret = VM_FAULT_MINOR;
- if (unlikely(!pfn_valid(pfn))) {
- /*
- * This should really halt the system so it can be debugged or
- * at least the kernel stops what it's doing before it corrupts
- * data, but for the moment just pretend this is OOM.
- */
- pte_unmap(page_table);
- printk(KERN_ERR "do_wp_page: bogus page at address %08lx\n",
- address);
- spin_unlock(&mm->page_table_lock);
- return VM_FAULT_OOM;
- }
- old_page = pfn_to_page(pfn);
+ old_page = vm_normal_page(vma, address, orig_pte);
+ if (!old_page)
+ goto gotten;
- if (!TestSetPageLocked(old_page)) {
+ if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
int reuse = can_share_swap_page(old_page);
unlock_page(old_page);
if (reuse) {
- flush_cache_page(vma, address);
- entry = maybe_mkwrite(pte_mkyoung(pte_mkdirty(pte)),
- vma);
+ flush_cache_page(vma, address, pte_pfn(orig_pte));
+ entry = pte_mkyoung(orig_pte);
+ entry = maybe_mkwrite(pte_mkdirty(entry), vma);
ptep_set_access_flags(vma, address, page_table, entry, 1);
update_mmu_cache(vma, address, entry);
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
- return VM_FAULT_MINOR;
+ lazy_mmu_prot_update(entry);
+ ret |= VM_FAULT_WRITE;
+ goto unlock;
}
}
- pte_unmap(page_table);
/*
* Ok, we need to copy. Oh, well..
*/
- if (!PageReserved(old_page))
- page_cache_get(old_page);
- spin_unlock(&mm->page_table_lock);
+ page_cache_get(old_page);
+gotten:
+ pte_unmap_unlock(page_table, ptl);
if (unlikely(anon_vma_prepare(vma)))
- goto no_new_page;
- new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
- if (!new_page)
- goto no_new_page;
- copy_cow_page(old_page,new_page,address);
+ goto oom;
+ if (old_page == ZERO_PAGE(address)) {
+ new_page = alloc_zeroed_user_highpage(vma, address);
+ if (!new_page)
+ goto oom;
+ } else {
+ new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
+ if (!new_page)
+ goto oom;
+ cow_user_page(new_page, old_page, address);
+ }
/*
* Re-check the pte - we dropped the lock
*/
- spin_lock(&mm->page_table_lock);
- page_table = pte_offset_map(pmd, address);
- if (likely(pte_same(*page_table, pte))) {
- if (PageReserved(old_page))
- // ++mm->rss;
- vx_rsspages_inc(mm);
- else
+ page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+ if (likely(pte_same(*page_table, orig_pte))) {
+ if (old_page) {
page_remove_rmap(old_page);
- break_cow(vma, new_page, address, page_table);
+ if (!PageAnon(old_page)) {
+ dec_mm_counter(mm, file_rss);
+ inc_mm_counter(mm, anon_rss);
+ }
+ } else
+ inc_mm_counter(mm, anon_rss);
+ flush_cache_page(vma, address, pte_pfn(orig_pte));
+ entry = mk_pte(new_page, vma->vm_page_prot);
+ entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+ ptep_establish(vma, address, page_table, entry);
+ update_mmu_cache(vma, address, entry);
+ lazy_mmu_prot_update(entry);
lru_cache_add_active(new_page);
- page_add_anon_rmap(new_page, vma, address);
+ page_add_new_anon_rmap(new_page, vma, address);
/* Free the old page.. */
new_page = old_page;
+ ret |= VM_FAULT_WRITE;
}
- pte_unmap(page_table);
- page_cache_release(new_page);
- page_cache_release(old_page);
- spin_unlock(&mm->page_table_lock);
- return VM_FAULT_MINOR;
-
-no_new_page:
- page_cache_release(old_page);
+ if (new_page)
+ page_cache_release(new_page);
+ if (old_page)
+ page_cache_release(old_page);
+unlock:
+ pte_unmap_unlock(page_table, ptl);
+ return ret;
+oom:
+ if (old_page)
+ page_cache_release(old_page);
return VM_FAULT_OOM;
}
/*
- * Helper function for unmap_mapping_range().
+ * Helper functions for unmap_mapping_range().
+ *
+ * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
+ *
+ * We have to restart searching the prio_tree whenever we drop the lock,
+ * since the iterator is only valid while the lock is held, and anyway
+ * a later vma might be split and reinserted earlier while lock dropped.
+ *
+ * The list of nonlinear vmas could be handled more efficiently, using
+ * a placeholder, but handle it in the same way until a need is shown.
+ * It is important to search the prio_tree before nonlinear list: a vma
+ * may become nonlinear and be shifted from prio_tree to nonlinear list
+ * while the lock is dropped; but never shifted from list to prio_tree.
+ *
+ * In order to make forward progress despite restarting the search,
+ * vm_truncate_count is used to mark a vma as now dealt with, so we can
+ * quickly skip it next time around. Since the prio_tree search only
+ * shows us those vmas affected by unmapping the range in question, we
+ * can't efficiently keep all vmas in step with mapping->truncate_count:
+ * so instead reset them all whenever it wraps back to 0 (then go to 1).
+ * mapping->truncate_count and vma->vm_truncate_count are protected by
+ * i_mmap_lock.
+ *
+ * In order to make forward progress despite repeatedly restarting some
+ * large vma, note the restart_addr from unmap_vmas when it breaks out:
+ * and restart from that address when we reach that vma again. It might
+ * have been split or merged, shrunk or extended, but never shifted: so
+ * restart_addr remains valid so long as it remains in the vma's range.
+ * unmap_mapping_range forces truncate_count to leap over page-aligned
+ * values so we can save vma's restart_addr in its truncate_count field.
*/
-static inline void unmap_mapping_range_list(struct prio_tree_root *root,
+#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
+
+static void reset_vma_truncate_counts(struct address_space *mapping)
+{
+ struct vm_area_struct *vma;
+ struct prio_tree_iter iter;
+
+ vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
+ vma->vm_truncate_count = 0;
+ list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
+ vma->vm_truncate_count = 0;
+}
+
+static int unmap_mapping_range_vma(struct vm_area_struct *vma,
+ unsigned long start_addr, unsigned long end_addr,
+ struct zap_details *details)
+{
+ unsigned long restart_addr;
+ int need_break;
+
+again:
+ restart_addr = vma->vm_truncate_count;
+ if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
+ start_addr = restart_addr;
+ if (start_addr >= end_addr) {
+ /* Top of vma has been split off since last time */
+ vma->vm_truncate_count = details->truncate_count;
+ return 0;
+ }
+ }
+
+ restart_addr = zap_page_range(vma, start_addr,
+ end_addr - start_addr, details);
+ need_break = need_resched() ||
+ need_lockbreak(details->i_mmap_lock);
+
+ if (restart_addr >= end_addr) {
+ /* We have now completed this vma: mark it so */
+ vma->vm_truncate_count = details->truncate_count;
+ if (!need_break)
+ return 0;
+ } else {
+ /* Note restart_addr in vma's truncate_count field */
+ vma->vm_truncate_count = restart_addr;
+ if (!need_break)
+ goto again;
+ }
+
+ spin_unlock(details->i_mmap_lock);
+ cond_resched();
+ spin_lock(details->i_mmap_lock);
+ return -EINTR;
+}
+
+static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
struct zap_details *details)
{
struct vm_area_struct *vma;
struct prio_tree_iter iter;
pgoff_t vba, vea, zba, zea;
+restart:
vma_prio_tree_foreach(vma, &iter, root,
details->first_index, details->last_index) {
+ /* Skip quickly over those we have already dealt with */
+ if (vma->vm_truncate_count == details->truncate_count)
+ continue;
+
vba = vma->vm_pgoff;
vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
/* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
zea = details->last_index;
if (zea > vea)
zea = vea;
- zap_page_range(vma,
+
+ if (unmap_mapping_range_vma(vma,
((zba - vba) << PAGE_SHIFT) + vma->vm_start,
- (zea - zba + 1) << PAGE_SHIFT, details);
+ ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
+ details) < 0)
+ goto restart;
+ }
+}
+
+static inline void unmap_mapping_range_list(struct list_head *head,
+ struct zap_details *details)
+{
+ struct vm_area_struct *vma;
+
+ /*
+ * In nonlinear VMAs there is no correspondence between virtual address
+ * offset and file offset. So we must perform an exhaustive search
+ * across *all* the pages in each nonlinear VMA, not just the pages
+ * whose virtual address lies outside the file truncation point.
+ */
+restart:
+ list_for_each_entry(vma, head, shared.vm_set.list) {
+ /* Skip quickly over those we have already dealt with */
+ if (vma->vm_truncate_count == details->truncate_count)
+ continue;
+ details->nonlinear_vma = vma;
+ if (unmap_mapping_range_vma(vma, vma->vm_start,
+ vma->vm_end, details) < 0)
+ goto restart;
}
}
* unmap_mapping_range - unmap the portion of all mmaps
* in the specified address_space corresponding to the specified
* page range in the underlying file.
- * @address_space: the address space containing mmaps to be unmapped.
+ * @mapping: the address space containing mmaps to be unmapped.
* @holebegin: byte in first page to unmap, relative to the start of
* the underlying file. This will be rounded down to a PAGE_SIZE
* boundary. Note that this is different from vmtruncate(), which
details.nonlinear_vma = NULL;
details.first_index = hba;
details.last_index = hba + hlen - 1;
- details.atomic = 1; /* A spinlock is held */
if (details.last_index < details.first_index)
details.last_index = ULONG_MAX;
+ details.i_mmap_lock = &mapping->i_mmap_lock;
spin_lock(&mapping->i_mmap_lock);
- /* Protect against page fault */
- atomic_inc(&mapping->truncate_count);
-
- if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
- unmap_mapping_range_list(&mapping->i_mmap, &details);
+ /* serialize i_size write against truncate_count write */
+ smp_wmb();
+ /* Protect against page faults, and endless unmapping loops */
+ mapping->truncate_count++;
/*
- * In nonlinear VMAs there is no correspondence between virtual address
- * offset and file offset. So we must perform an exhaustive search
- * across *all* the pages in each nonlinear VMA, not just the pages
- * whose virtual address lies outside the file truncation point.
+ * For archs where spin_lock has inclusive semantics like ia64
+ * this smp_mb() will prevent to read pagetable contents
+ * before the truncate_count increment is visible to
+ * other cpus.
*/
- if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) {
- struct vm_area_struct *vma;
- list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
- shared.vm_set.list) {
- details.nonlinear_vma = vma;
- zap_page_range(vma, vma->vm_start,
- vma->vm_end - vma->vm_start, &details);
- }
+ smp_mb();
+ if (unlikely(is_restart_addr(mapping->truncate_count))) {
+ if (mapping->truncate_count == 0)
+ reset_vma_truncate_counts(mapping);
+ mapping->truncate_count++;
}
+ details.truncate_count = mapping->truncate_count;
+
+ if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
+ unmap_mapping_range_tree(&mapping->i_mmap, &details);
+ if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
+ unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
spin_unlock(&mapping->i_mmap_lock);
}
EXPORT_SYMBOL(unmap_mapping_range);
goto out_truncate;
do_expand:
- limit = current->rlim[RLIMIT_FSIZE].rlim_cur;
+ limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
if (limit != RLIM_INFINITY && offset > limit)
goto out_sig;
if (offset > inode->i_sb->s_maxbytes)
out_busy:
return -ETXTBSY;
}
-
EXPORT_SYMBOL(vmtruncate);
+int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
+{
+ struct address_space *mapping = inode->i_mapping;
+
+ /*
+ * If the underlying filesystem is not going to provide
+ * a way to truncate a range of blocks (punch a hole) -
+ * we should return failure right now.
+ */
+ if (!inode->i_op || !inode->i_op->truncate_range)
+ return -ENOSYS;
+
+ mutex_lock(&inode->i_mutex);
+ down_write(&inode->i_alloc_sem);
+ unmap_mapping_range(mapping, offset, (end - offset), 1);
+ truncate_inode_pages_range(mapping, offset, end);
+ inode->i_op->truncate_range(inode, offset, end);
+ up_write(&inode->i_alloc_sem);
+ mutex_unlock(&inode->i_mutex);
+
+ return 0;
+}
+EXPORT_SYMBOL(vmtruncate_range);
+
/*
* Primitive swap readahead code. We simply read an aligned block of
* (1 << page_cluster) entries in the swap area. This method is chosen
}
/*
- * We hold the mm semaphore and the page_table_lock on entry and
- * should release the pagetable lock on exit..
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
-static int do_swap_page(struct mm_struct * mm,
- struct vm_area_struct * vma, unsigned long address,
- pte_t *page_table, pmd_t *pmd, pte_t orig_pte, int write_access)
+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)
{
+ spinlock_t *ptl;
struct page *page;
- swp_entry_t entry = pte_to_swp_entry(orig_pte);
+ swp_entry_t entry;
pte_t pte;
int ret = VM_FAULT_MINOR;
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
+ if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
+ goto out;
+
+ entry = pte_to_swp_entry(orig_pte);
+again:
page = lookup_swap_cache(entry);
if (!page) {
swapin_readahead(entry, address, vma);
page = read_swap_cache_async(entry, vma, address);
if (!page) {
/*
- * Back out if somebody else faulted in this pte while
- * we released the page table lock.
+ * Back out if somebody else faulted in this pte
+ * while we released the pte lock.
*/
- spin_lock(&mm->page_table_lock);
- page_table = pte_offset_map(pmd, address);
+ page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
if (likely(pte_same(*page_table, orig_pte)))
ret = VM_FAULT_OOM;
- else
- ret = VM_FAULT_MINOR;
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
- goto out;
+ goto unlock;
}
/* Had to read the page from swap area: Major fault */
}
mark_page_accessed(page);
lock_page(page);
+ if (!PageSwapCache(page)) {
+ /* Page migration has occured */
+ unlock_page(page);
+ page_cache_release(page);
+ goto again;
+ }
/*
- * Back out if somebody else faulted in this pte while we
- * released the page table lock.
+ * Back out if somebody else already faulted in this pte.
*/
- spin_lock(&mm->page_table_lock);
- page_table = pte_offset_map(pmd, address);
- if (unlikely(!pte_same(*page_table, orig_pte))) {
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
- unlock_page(page);
- page_cache_release(page);
- ret = VM_FAULT_MINOR;
- goto out;
+ page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+ if (unlikely(!pte_same(*page_table, orig_pte)))
+ goto out_nomap;
+
+ if (unlikely(!PageUptodate(page))) {
+ ret = VM_FAULT_SIGBUS;
+ goto out_nomap;
}
/* The page isn't present yet, go ahead with the fault. */
-
- swap_free(entry);
- if (vm_swap_full())
- remove_exclusive_swap_page(page);
- // mm->rss++;
- vx_rsspages_inc(mm);
+ inc_mm_counter(mm, anon_rss);
pte = mk_pte(page, vma->vm_page_prot);
if (write_access && can_share_swap_page(page)) {
pte = maybe_mkwrite(pte_mkdirty(pte), vma);
write_access = 0;
}
- unlock_page(page);
flush_icache_page(vma, page);
- set_pte(page_table, pte);
+ set_pte_at(mm, address, page_table, pte);
page_add_anon_rmap(page, vma, address);
+ swap_free(entry);
+ if (vm_swap_full())
+ remove_exclusive_swap_page(page);
+ unlock_page(page);
+
if (write_access) {
if (do_wp_page(mm, vma, address,
- page_table, pmd, pte) == VM_FAULT_OOM)
+ page_table, pmd, ptl, pte) == VM_FAULT_OOM)
ret = VM_FAULT_OOM;
goto out;
}
/* No need to invalidate - it was non-present before */
update_mmu_cache(vma, address, pte);
- pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
+ lazy_mmu_prot_update(pte);
+unlock:
+ pte_unmap_unlock(page_table, ptl);
out:
return ret;
+out_nomap:
+ pte_unmap_unlock(page_table, ptl);
+ unlock_page(page);
+ page_cache_release(page);
+ return ret;
}
/*
- * We are called with the MM semaphore and page_table_lock
- * spinlock held to protect against concurrent faults in
- * multithreaded programs.
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
-static int
-do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
- pte_t *page_table, pmd_t *pmd, int write_access,
- unsigned long addr)
+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)
{
+ struct page *page;
+ spinlock_t *ptl;
pte_t entry;
- struct page * page = ZERO_PAGE(addr);
- /* Read-only mapping of ZERO_PAGE. */
- entry = pte_wrprotect(mk_pte(ZERO_PAGE(addr), vma->vm_page_prot));
-
- /* ..except if it's a write access */
if (write_access) {
/* Allocate our own private page. */
pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
- if (unlikely(anon_vma_prepare(vma)))
- goto no_mem;
if (!vx_rsspages_avail(mm, 1))
- goto no_mem;
-
- page = alloc_page_vma(GFP_HIGHUSER, vma, addr);
+ goto oom;
+ if (unlikely(anon_vma_prepare(vma)))
+ goto oom;
+ page = alloc_zeroed_user_highpage(vma, address);
if (!page)
- goto no_mem;
- clear_user_highpage(page, addr);
+ goto oom;
- spin_lock(&mm->page_table_lock);
- page_table = pte_offset_map(pmd, addr);
+ entry = mk_pte(page, vma->vm_page_prot);
+ entry = maybe_mkwrite(pte_mkdirty(entry), vma);
- if (!pte_none(*page_table)) {
- pte_unmap(page_table);
- page_cache_release(page);
- spin_unlock(&mm->page_table_lock);
- goto out;
- }
- // mm->rss++;
- vx_rsspages_inc(mm);
- entry = maybe_mkwrite(pte_mkdirty(mk_pte(page,
- vma->vm_page_prot)),
- vma);
+ page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+ if (!pte_none(*page_table))
+ goto release;
+ inc_mm_counter(mm, anon_rss);
lru_cache_add_active(page);
- mark_page_accessed(page);
- page_add_anon_rmap(page, vma, addr);
+ page_add_new_anon_rmap(page, vma, address);
+ } else {
+ /* Map the ZERO_PAGE - vm_page_prot is readonly */
+ page = ZERO_PAGE(address);
+ page_cache_get(page);
+ entry = mk_pte(page, vma->vm_page_prot);
+
+ ptl = pte_lockptr(mm, pmd);
+ spin_lock(ptl);
+ if (!pte_none(*page_table))
+ goto release;
+ inc_mm_counter(mm, file_rss);
+ page_add_file_rmap(page);
}
- set_pte(page_table, entry);
- pte_unmap(page_table);
+ set_pte_at(mm, address, page_table, entry);
/* No need to invalidate - it was non-present before */
- update_mmu_cache(vma, addr, entry);
- spin_unlock(&mm->page_table_lock);
-out:
+ update_mmu_cache(vma, address, entry);
+ lazy_mmu_prot_update(entry);
+unlock:
+ pte_unmap_unlock(page_table, ptl);
return VM_FAULT_MINOR;
-no_mem:
+release:
+ page_cache_release(page);
+ goto unlock;
+oom:
return VM_FAULT_OOM;
}
* As this is called only for pages that do not currently exist, we
* do not need to flush old virtual caches or the TLB.
*
- * This is called with the MM semaphore held and the page table
- * spinlock held. Exit with the spinlock released.
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
-static int
-do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
+static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, pte_t *page_table, pmd_t *pmd,
+ int write_access)
{
- struct page * new_page;
+ spinlock_t *ptl;
+ struct page *new_page;
struct address_space *mapping = NULL;
pte_t entry;
- int sequence = 0;
+ unsigned int sequence = 0;
int ret = VM_FAULT_MINOR;
int anon = 0;
- if (!vma->vm_ops || !vma->vm_ops->nopage)
- return do_anonymous_page(mm, vma, page_table,
- pmd, write_access, address);
pte_unmap(page_table);
- spin_unlock(&mm->page_table_lock);
+ BUG_ON(vma->vm_flags & VM_PFNMAP);
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
- sequence = atomic_read(&mapping->truncate_count);
+ sequence = mapping->truncate_count;
+ smp_rmb(); /* serializes i_size against truncate_count */
}
- smp_rmb(); /* Prevent CPU from reordering lock-free ->nopage() */
retry:
+ /* FIXME: is that check useful here? */
+ if (!vx_rsspages_avail(mm, 1))
+ return VM_FAULT_OOM;
new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
+ /*
+ * No smp_rmb is needed here as long as there's a full
+ * spin_lock/unlock sequence inside the ->nopage callback
+ * (for the pagecache lookup) that acts as an implicit
+ * smp_mb() and prevents the i_size read to happen
+ * after the next truncate_count read.
+ */
/* no page was available -- either SIGBUS or OOM */
if (new_page == NOPAGE_SIGBUS)
return VM_FAULT_SIGBUS;
if (new_page == NOPAGE_OOM)
return VM_FAULT_OOM;
- if (!vx_rsspages_avail(mm, 1))
- return VM_FAULT_OOM;
/*
* Should we do an early C-O-W break?
anon = 1;
}
- spin_lock(&mm->page_table_lock);
+ page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
/*
* For a file-backed vma, someone could have truncated or otherwise
* invalidated this page. If unmap_mapping_range got called,
* retry getting the page.
*/
- if (mapping &&
- (unlikely(sequence != atomic_read(&mapping->truncate_count)))) {
- sequence = atomic_read(&mapping->truncate_count);
- spin_unlock(&mm->page_table_lock);
+ if (mapping && unlikely(sequence != mapping->truncate_count)) {
+ pte_unmap_unlock(page_table, ptl);
page_cache_release(new_page);
+ cond_resched();
+ sequence = mapping->truncate_count;
+ smp_rmb();
goto retry;
}
- page_table = pte_offset_map(pmd, address);
/*
* This silly early PAGE_DIRTY setting removes a race
*/
/* Only go through if we didn't race with anybody else... */
if (pte_none(*page_table)) {
- if (!PageReserved(new_page))
- // ++mm->rss;
- vx_rsspages_inc(mm);
flush_icache_page(vma, new_page);
entry = mk_pte(new_page, vma->vm_page_prot);
if (write_access)
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
- set_pte(page_table, entry);
+ set_pte_at(mm, address, page_table, entry);
if (anon) {
+ inc_mm_counter(mm, anon_rss);
lru_cache_add_active(new_page);
- page_add_anon_rmap(new_page, vma, address);
- } else
+ page_add_new_anon_rmap(new_page, vma, address);
+ } else {
+ inc_mm_counter(mm, file_rss);
page_add_file_rmap(new_page);
- pte_unmap(page_table);
+ }
} else {
/* One of our sibling threads was faster, back out. */
- pte_unmap(page_table);
page_cache_release(new_page);
- spin_unlock(&mm->page_table_lock);
- goto out;
+ goto unlock;
}
/* no need to invalidate: a not-present page shouldn't be cached */
update_mmu_cache(vma, address, entry);
- spin_unlock(&mm->page_table_lock);
-out:
+ lazy_mmu_prot_update(entry);
+unlock:
+ pte_unmap_unlock(page_table, ptl);
return ret;
oom:
page_cache_release(new_page);
- ret = VM_FAULT_OOM;
- goto out;
+ return VM_FAULT_OOM;
}
/*
* Fault of a previously existing named mapping. Repopulate the pte
* from the encoded file_pte if possible. This enables swappable
* nonlinear vmas.
+ *
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
-static int do_file_page(struct mm_struct * mm, struct vm_area_struct * vma,
- unsigned long address, int write_access, pte_t *pte, pmd_t *pmd)
+static int do_file_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 long pgoff;
+ pgoff_t pgoff;
int err;
- BUG_ON(!vma->vm_ops || !vma->vm_ops->nopage);
- /*
- * Fall back to the linear mapping if the fs does not support
- * ->populate:
- */
- if (!vma->vm_ops || !vma->vm_ops->populate ||
- (write_access && !(vma->vm_flags & VM_SHARED))) {
- pte_clear(pte);
- return do_no_page(mm, vma, address, write_access, pte, pmd);
- }
-
- pgoff = pte_to_pgoff(*pte);
+ if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
+ return VM_FAULT_MINOR;
- pte_unmap(pte);
- spin_unlock(&mm->page_table_lock);
+ if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
+ /*
+ * Page table corrupted: show pte and kill process.
+ */
+ print_bad_pte(vma, orig_pte, address);
+ return VM_FAULT_OOM;
+ }
+ /* We can then assume vm->vm_ops && vma->vm_ops->populate */
- err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, vma->vm_page_prot, pgoff, 0);
+ pgoff = pte_to_pgoff(orig_pte);
+ err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE,
+ vma->vm_page_prot, pgoff, 0);
if (err == -ENOMEM)
return VM_FAULT_OOM;
if (err)
* with external mmu caches can use to update those (ie the Sparc or
* PowerPC hashed page tables that act as extended TLBs).
*
- * Note the "page_table_lock". It is to protect against kswapd removing
- * pages from under us. Note that kswapd only ever _removes_ pages, never
- * adds them. As such, once we have noticed that the page is not present,
- * we can drop the lock early.
- *
- * The adding of pages is protected by the MM semaphore (which we hold),
- * so we don't need to worry about a page being suddenly been added into
- * our VM.
- *
- * We enter with the pagetable spinlock held, we are supposed to
- * release it when done.
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
static inline int handle_pte_fault(struct mm_struct *mm,
- struct vm_area_struct * vma, unsigned long address,
- int write_access, pte_t *pte, pmd_t *pmd)
+ struct vm_area_struct *vma, unsigned long address,
+ pte_t *pte, pmd_t *pmd, int write_access)
{
pte_t entry;
+ pte_t old_entry;
+ spinlock_t *ptl;
- entry = *pte;
+ old_entry = entry = *pte;
if (!pte_present(entry)) {
- /*
- * If it truly wasn't present, we know that kswapd
- * and the PTE updates will not touch it later. So
- * drop the lock.
- */
- if (pte_none(entry))
- return do_no_page(mm, vma, address, write_access, pte, pmd);
+ if (pte_none(entry)) {
+ if (!vma->vm_ops || !vma->vm_ops->nopage)
+ return do_anonymous_page(mm, vma, address,
+ pte, pmd, write_access);
+ return do_no_page(mm, vma, address,
+ pte, pmd, write_access);
+ }
if (pte_file(entry))
- return do_file_page(mm, vma, address, write_access, pte, pmd);
- return do_swap_page(mm, vma, address, pte, pmd, entry, write_access);
+ return do_file_page(mm, vma, address,
+ pte, pmd, write_access, entry);
+ return do_swap_page(mm, vma, address,
+ pte, pmd, write_access, entry);
}
+ ptl = pte_lockptr(mm, pmd);
+ spin_lock(ptl);
+ if (unlikely(!pte_same(*pte, entry)))
+ goto unlock;
if (write_access) {
if (!pte_write(entry))
- return do_wp_page(mm, vma, address, pte, pmd, entry);
-
+ return do_wp_page(mm, vma, address,
+ pte, pmd, ptl, entry);
entry = pte_mkdirty(entry);
}
entry = pte_mkyoung(entry);
- ptep_set_access_flags(vma, address, pte, entry, write_access);
- update_mmu_cache(vma, address, entry);
- pte_unmap(pte);
- spin_unlock(&mm->page_table_lock);
+ if (!pte_same(old_entry, entry)) {
+ ptep_set_access_flags(vma, address, pte, entry, write_access);
+ update_mmu_cache(vma, address, entry);
+ lazy_mmu_prot_update(entry);
+ } else {
+ /*
+ * This is needed only for protection faults but the arch code
+ * is not yet telling us if this is a protection fault or not.
+ * This still avoids useless tlb flushes for .text page faults
+ * with threads.
+ */
+ if (write_access)
+ flush_tlb_page(vma, address);
+ }
+unlock:
+ pte_unmap_unlock(pte, ptl);
return VM_FAULT_MINOR;
}
/*
* 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)
+int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, int write_access)
{
pgd_t *pgd;
+ pud_t *pud;
pmd_t *pmd;
+ pte_t *pte;
__set_current_state(TASK_RUNNING);
- pgd = pgd_offset(mm, address);
inc_page_state(pgfault);
- if (is_vm_hugetlb_page(vma))
- return VM_FAULT_SIGBUS; /* mapping truncation does this. */
+ if (unlikely(is_vm_hugetlb_page(vma)))
+ return hugetlb_fault(mm, vma, address, write_access);
- /*
- * We need the page table lock to synchronize with kswapd
- * and the SMP-safe atomic PTE updates.
- */
- spin_lock(&mm->page_table_lock);
- pmd = pmd_alloc(mm, pgd, address);
+ pgd = pgd_offset(mm, address);
+ pud = pud_alloc(mm, pgd, address);
+ if (!pud)
+ return VM_FAULT_OOM;
+ pmd = pmd_alloc(mm, pud, address);
+ if (!pmd)
+ return VM_FAULT_OOM;
+ pte = pte_alloc_map(mm, pmd, address);
+ if (!pte)
+ return VM_FAULT_OOM;
- if (pmd) {
- pte_t * pte = pte_alloc_map(mm, pmd, address);
- if (pte)
- return handle_pte_fault(mm, vma, address, write_access, pte, pmd);
- }
- spin_unlock(&mm->page_table_lock);
- return VM_FAULT_OOM;
+ return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
}
+EXPORT_SYMBOL_GPL(__handle_mm_fault);
+
+#ifndef __PAGETABLE_PUD_FOLDED
/*
- * Allocate page middle directory.
- *
- * We've already handled the fast-path in-line, and we own the
- * page table lock.
- *
- * On a two-level page table, this ends up actually being entirely
- * optimized away.
+ * Allocate page upper directory.
+ * We've already handled the fast-path in-line.
*/
-pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
+int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
{
- pmd_t *new;
+ pud_t *new = pud_alloc_one(mm, address);
+ if (!new)
+ return -ENOMEM;
- spin_unlock(&mm->page_table_lock);
- new = pmd_alloc_one(mm, address);
spin_lock(&mm->page_table_lock);
+ if (pgd_present(*pgd)) /* Another has populated it */
+ pud_free(new);
+ else
+ pgd_populate(mm, pgd, new);
+ spin_unlock(&mm->page_table_lock);
+ return 0;
+}
+#else
+/* Workaround for gcc 2.96 */
+int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
+{
+ return 0;
+}
+#endif /* __PAGETABLE_PUD_FOLDED */
+
+#ifndef __PAGETABLE_PMD_FOLDED
+/*
+ * Allocate page middle directory.
+ * We've already handled the fast-path in-line.
+ */
+int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
+{
+ pmd_t *new = pmd_alloc_one(mm, address);
if (!new)
- return NULL;
+ return -ENOMEM;
- /*
- * Because we dropped the lock, we should re-check the
- * entry, as somebody else could have populated it..
- */
- if (pgd_present(*pgd)) {
+ spin_lock(&mm->page_table_lock);
+#ifndef __ARCH_HAS_4LEVEL_HACK
+ if (pud_present(*pud)) /* Another has populated it */
pmd_free(new);
- goto out;
- }
- pgd_populate(mm, pgd, new);
-out:
- return pmd_offset(pgd, address);
+ else
+ pud_populate(mm, pud, new);
+#else
+ if (pgd_present(*pud)) /* Another has populated it */
+ pmd_free(new);
+ else
+ pgd_populate(mm, pud, new);
+#endif /* __ARCH_HAS_4LEVEL_HACK */
+ spin_unlock(&mm->page_table_lock);
+ return 0;
+}
+#else
+/* Workaround for gcc 2.96 */
+int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
+{
+ return 0;
}
+#endif /* __PAGETABLE_PMD_FOLDED */
int make_pages_present(unsigned long addr, unsigned long end)
{
if (!vma)
return -1;
write = (vma->vm_flags & VM_WRITE) != 0;
- if (addr >= end)
- BUG();
- if (end > vma->vm_end)
- BUG();
+ BUG_ON(addr >= end);
+ BUG_ON(end > vma->vm_end);
len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
ret = get_user_pages(current, current->mm, addr,
len, write, 0, NULL, NULL);
unsigned long addr = (unsigned long) vmalloc_addr;
struct page *page = NULL;
pgd_t *pgd = pgd_offset_k(addr);
+ pud_t *pud;
pmd_t *pmd;
pte_t *ptep, pte;
if (!pgd_none(*pgd)) {
- pmd = pmd_offset(pgd, addr);
- if (!pmd_none(*pmd)) {
- preempt_disable();
- ptep = pte_offset_map(pmd, addr);
- pte = *ptep;
- if (pte_present(pte))
- page = pte_page(pte);
- pte_unmap(ptep);
- preempt_enable();
+ pud = pud_offset(pgd, addr);
+ if (!pud_none(*pud)) {
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_none(*pmd)) {
+ ptep = pte_offset_map(pmd, addr);
+ pte = *ptep;
+ if (pte_present(pte))
+ page = pte_page(pte);
+ pte_unmap(ptep);
+ }
}
}
return page;
EXPORT_SYMBOL(vmalloc_to_page);
-#if !defined(CONFIG_ARCH_GATE_AREA)
+/*
+ * Map a vmalloc()-space virtual address to the physical page frame number.
+ */
+unsigned long vmalloc_to_pfn(void * vmalloc_addr)
+{
+ return page_to_pfn(vmalloc_to_page(vmalloc_addr));
+}
+
+EXPORT_SYMBOL(vmalloc_to_pfn);
+
+#if !defined(__HAVE_ARCH_GATE_AREA)
#if defined(AT_SYSINFO_EHDR)
-struct vm_area_struct gate_vma;
+static struct vm_area_struct gate_vma;
static int __init gate_vma_init(void)
{
#endif
}
-int in_gate_area(struct task_struct *task, unsigned long addr)
+int in_gate_area_no_task(unsigned long addr)
{
#ifdef AT_SYSINFO_EHDR
if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
return 0;
}
-#endif
+#endif /* __HAVE_ARCH_GATE_AREA */
git://git.onelab.eu / linux-2.6.git / blobdiff