i386: move mm

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 391 insertions, 0 deletions

diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
new file mode 100644
index 000000000000..6c06d9c0488e
--- /dev/null
+++ b/arch/x86/mm/hugetlbpage.c
@@ -0,0 +1,391 @@
+/*
+ * IA-32 Huge TLB Page Support for Kernel.
+ *
+ * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
+ */
+
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/sysctl.h>
+#include <asm/mman.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+
+static unsigned long page_table_shareable(struct vm_area_struct *svma,
+                                struct vm_area_struct *vma,
+                                unsigned long addr, pgoff_t idx)
+{
+        unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
+                                svma->vm_start;
+        unsigned long sbase = saddr & PUD_MASK;
+        unsigned long s_end = sbase + PUD_SIZE;
+
+        /*
+         * match the virtual addresses, permission and the alignment of the
+         * page table page.
+         */
+        if (pmd_index(addr) != pmd_index(saddr) ||
+            vma->vm_flags != svma->vm_flags ||
+            sbase < svma->vm_start || svma->vm_end < s_end)
+                return 0;
+
+        return saddr;
+}
+
+static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
+{
+        unsigned long base = addr & PUD_MASK;
+        unsigned long end = base + PUD_SIZE;
+
+        /*
+         * check on proper vm_flags and page table alignment
+         */
+        if (vma->vm_flags & VM_MAYSHARE &&
+            vma->vm_start <= base && end <= vma->vm_end)
+                return 1;
+        return 0;
+}
+
+/*
+ * search for a shareable pmd page for hugetlb.
+ */
+static void huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
+{
+        struct vm_area_struct *vma = find_vma(mm, addr);
+        struct address_space *mapping = vma->vm_file->f_mapping;
+        pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
+                        vma->vm_pgoff;
+        struct prio_tree_iter iter;
+        struct vm_area_struct *svma;
+        unsigned long saddr;
+        pte_t *spte = NULL;
+
+        if (!vma_shareable(vma, addr))
+                return;
+
+        spin_lock(&mapping->i_mmap_lock);
+        vma_prio_tree_foreach(svma, &iter, &mapping->i_mmap, idx, idx) {
+                if (svma == vma)
+                        continue;
+
+                saddr = page_table_shareable(svma, vma, addr, idx);
+                if (saddr) {
+                        spte = huge_pte_offset(svma->vm_mm, saddr);
+                        if (spte) {
+                                get_page(virt_to_page(spte));
+                                break;
+                        }
+                }
+        }
+
+        if (!spte)
+                goto out;
+
+        spin_lock(&mm->page_table_lock);
+        if (pud_none(*pud))
+                pud_populate(mm, pud, (unsigned long) spte & PAGE_MASK);
+        else
+                put_page(virt_to_page(spte));
+        spin_unlock(&mm->page_table_lock);
+out:
+        spin_unlock(&mapping->i_mmap_lock);
+}
+
+/*
+ * unmap huge page backed by shared pte.
+ *
+ * Hugetlb pte page is ref counted at the time of mapping.  If pte is shared
+ * indicated by page_count > 1, unmap is achieved by clearing pud and
+ * decrementing the ref count. If count == 1, the pte page is not shared.
+ *
+ * called with vma->vm_mm->page_table_lock held.
+ *
+ * returns: 1 successfully unmapped a shared pte page
+ *          0 the underlying pte page is not shared, or it is the last user
+ */
+int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
+{
+        pgd_t *pgd = pgd_offset(mm, *addr);
+        pud_t *pud = pud_offset(pgd, *addr);
+
+        BUG_ON(page_count(virt_to_page(ptep)) == 0);
+        if (page_count(virt_to_page(ptep)) == 1)
+                return 0;
+
+        pud_clear(pud);
+        put_page(virt_to_page(ptep));
+        *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
+        return 1;
+}
+
+pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pte_t *pte = NULL;
+
+        pgd = pgd_offset(mm, addr);
+        pud = pud_alloc(mm, pgd, addr);
+        if (pud) {
+                if (pud_none(*pud))
+                        huge_pmd_share(mm, addr, pud);
+                pte = (pte_t *) pmd_alloc(mm, pud, addr);
+        }
+        BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
+
+        return pte;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd = NULL;
+
+        pgd = pgd_offset(mm, addr);
+        if (pgd_present(*pgd)) {
+                pud = pud_offset(pgd, addr);
+                if (pud_present(*pud))
+                        pmd = pmd_offset(pud, addr);
+        }
+        return (pte_t *) pmd;
+}
+
+#if 0   /* This is just for testing */
+struct page *
+follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
+{
+        unsigned long start = address;
+        int length = 1;
+        int nr;
+        struct page *page;
+        struct vm_area_struct *vma;
+
+        vma = find_vma(mm, addr);
+        if (!vma || !is_vm_hugetlb_page(vma))
+                return ERR_PTR(-EINVAL);
+
+        pte = huge_pte_offset(mm, address);
+
+        /* hugetlb should be locked, and hence, prefaulted */
+        WARN_ON(!pte || pte_none(*pte));
+
+        page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
+
+        WARN_ON(!PageCompound(page));
+
+        return page;
+}
+
+int pmd_huge(pmd_t pmd)
+{
+        return 0;
+}
+
+struct page *
+follow_huge_pmd(struct mm_struct *mm, unsigned long address,
+                pmd_t *pmd, int write)
+{
+        return NULL;
+}
+
+#else
+
+struct page *
+follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
+{
+        return ERR_PTR(-EINVAL);
+}
+
+int pmd_huge(pmd_t pmd)
+{
+        return !!(pmd_val(pmd) & _PAGE_PSE);
+}
+
+struct page *
+follow_huge_pmd(struct mm_struct *mm, unsigned long address,
+                pmd_t *pmd, int write)
+{
+        struct page *page;
+
+        page = pte_page(*(pte_t *)pmd);
+        if (page)
+                page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
+        return page;
+}
+#endif
+
+/* x86_64 also uses this file */
+
+#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
+static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
+                unsigned long addr, unsigned long len,
+                unsigned long pgoff, unsigned long flags)
+{
+        struct mm_struct *mm = current->mm;
+        struct vm_area_struct *vma;
+        unsigned long start_addr;
+
+        if (len > mm->cached_hole_size) {
+                start_addr = mm->free_area_cache;
+        } else {
+                start_addr = TASK_UNMAPPED_BASE;
+                mm->cached_hole_size = 0;
+        }
+
+full_search:
+        addr = ALIGN(start_addr, HPAGE_SIZE);
+
+        for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
+                /* At this point:  (!vma || addr < vma->vm_end). */
+                if (TASK_SIZE - len < addr) {
+                        /*
+                         * Start a new search - just in case we missed
+                         * some holes.
+                         */
+                        if (start_addr != TASK_UNMAPPED_BASE) {
+                                start_addr = TASK_UNMAPPED_BASE;
+                                mm->cached_hole_size = 0;
+                                goto full_search;
+                        }
+                        return -ENOMEM;
+                }
+                if (!vma || addr + len <= vma->vm_start) {
+                        mm->free_area_cache = addr + len;
+                        return addr;
+                }
+                if (addr + mm->cached_hole_size < vma->vm_start)
+                        mm->cached_hole_size = vma->vm_start - addr;
+                addr = ALIGN(vma->vm_end, HPAGE_SIZE);
+        }
+}
+
+static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
+                unsigned long addr0, unsigned long len,
+                unsigned long pgoff, unsigned long flags)
+{
+        struct mm_struct *mm = current->mm;
+        struct vm_area_struct *vma, *prev_vma;
+        unsigned long base = mm->mmap_base, addr = addr0;
+        unsigned long largest_hole = mm->cached_hole_size;
+        int first_time = 1;
+
+        /* don't allow allocations above current base */
+        if (mm->free_area_cache > base)
+                mm->free_area_cache = base;
+
+        if (len <= largest_hole) {
+                largest_hole = 0;
+                mm->free_area_cache  = base;
+        }
+try_again:
+        /* make sure it can fit in the remaining address space */
+        if (mm->free_area_cache < len)
+                goto fail;
+
+        /* either no address requested or cant fit in requested address hole */
+        addr = (mm->free_area_cache - len) & HPAGE_MASK;
+        do {
+                /*
+                 * Lookup failure means no vma is above this address,
+                 * i.e. return with success:
+                 */
+                if (!(vma = find_vma_prev(mm, addr, &prev_vma)))
+                        return addr;
+
+                /*
+                 * new region fits between prev_vma->vm_end and
+                 * vma->vm_start, use it:
+                 */
+                if (addr + len <= vma->vm_start &&
+                            (!prev_vma || (addr >= prev_vma->vm_end))) {
+                        /* remember the address as a hint for next time */
+                        mm->cached_hole_size = largest_hole;
+                        return (mm->free_area_cache = addr);
+                } else {
+                        /* pull free_area_cache down to the first hole */
+                        if (mm->free_area_cache == vma->vm_end) {
+                                mm->free_area_cache = vma->vm_start;
+                                mm->cached_hole_size = largest_hole;
+                        }
+                }
+
+                /* remember the largest hole we saw so far */
+                if (addr + largest_hole < vma->vm_start)
+                        largest_hole = vma->vm_start - addr;
+
+                /* try just below the current vma->vm_start */
+                addr = (vma->vm_start - len) & HPAGE_MASK;
+        } while (len <= vma->vm_start);
+
+fail:
+        /*
+         * if hint left us with no space for the requested
+         * mapping then try again:
+         */
+        if (first_time) {
+                mm->free_area_cache = base;
+                largest_hole = 0;
+                first_time = 0;
+                goto try_again;
+        }
+        /*
+         * A failed mmap() very likely causes application failure,
+         * so fall back to the bottom-up function here. This scenario
+         * can happen with large stack limits and large mmap()
+         * allocations.
+         */
+        mm->free_area_cache = TASK_UNMAPPED_BASE;
+        mm->cached_hole_size = ~0UL;
+        addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
+                        len, pgoff, flags);
+
+        /*
+         * Restore the topdown base:
+         */
+        mm->free_area_cache = base;
+        mm->cached_hole_size = ~0UL;
+
+        return addr;
+}
+
+unsigned long
+hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
+                unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+        struct mm_struct *mm = current->mm;
+        struct vm_area_struct *vma;
+
+        if (len & ~HPAGE_MASK)
+                return -EINVAL;
+        if (len > TASK_SIZE)
+                return -ENOMEM;
+
+        if (flags & MAP_FIXED) {
+                if (prepare_hugepage_range(addr, len))
+                        return -EINVAL;
+                return addr;
+        }
+
+        if (addr) {
+                addr = ALIGN(addr, HPAGE_SIZE);
+                vma = find_vma(mm, addr);
+                if (TASK_SIZE - len >= addr &&
+                    (!vma || addr + len <= vma->vm_start))
+                        return addr;
+        }
+        if (mm->get_unmapped_area == arch_get_unmapped_area)
+                return hugetlb_get_unmapped_area_bottomup(file, addr, len,
+                                pgoff, flags);
+        else
+                return hugetlb_get_unmapped_area_topdown(file, addr, len,
+                                pgoff, flags);
+}
+
+#endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
+