1 files changed, 431 insertions, 0 deletions

diff --git a/arch/i386/mm/hugetlbpage.c b/arch/i386/mm/hugetlbpage.c
new file mode 100644
index 000000000000..a8c45143088b
--- /dev/null
+++ b/arch/i386/mm/hugetlbpage.c
@@ -0,0 +1,431 @@
+/*
+ * IA-32 Huge TLB Page Support for Kernel.
+ *
+ * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
+ */
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/pagemap.h>
+#include <linux/smp_lock.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 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
+{
+        pgd_t *pgd;
+        pud_t *pud;
+        pmd_t *pmd = NULL;
+
+        pgd = pgd_offset(mm, addr);
+        pud = pud_alloc(mm, pgd, addr);
+        pmd = pmd_alloc(mm, pud, addr);
+        return (pte_t *) pmd;
+}
+
+static 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);
+        pud = pud_offset(pgd, addr);
+        pmd = pmd_offset(pud, addr);
+        return (pte_t *) pmd;
+}
+
+static void set_huge_pte(struct mm_struct *mm, struct vm_area_struct *vma, struct page *page, pte_t * page_table, int write_access)
+{
+        pte_t entry;
+
+        add_mm_counter(mm, rss, HPAGE_SIZE / PAGE_SIZE);
+        if (write_access) {
+                entry =
+                    pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
+        } else
+                entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
+        entry = pte_mkyoung(entry);
+        mk_pte_huge(entry);
+        set_pte(page_table, entry);
+}
+
+/*
+ * This function checks for proper alignment of input addr and len parameters.
+ */
+int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
+{
+        if (len & ~HPAGE_MASK)
+                return -EINVAL;
+        if (addr & ~HPAGE_MASK)
+                return -EINVAL;
+        return 0;
+}
+
+int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
+                        struct vm_area_struct *vma)
+{
+        pte_t *src_pte, *dst_pte, entry;
+        struct page *ptepage;
+        unsigned long addr = vma->vm_start;
+        unsigned long end = vma->vm_end;
+
+        while (addr < end) {
+                dst_pte = huge_pte_alloc(dst, addr);
+                if (!dst_pte)
+                        goto nomem;
+                src_pte = huge_pte_offset(src, addr);
+                entry = *src_pte;
+                ptepage = pte_page(entry);
+                get_page(ptepage);
+                set_pte(dst_pte, entry);
+                add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
+                addr += HPAGE_SIZE;
+        }
+        return 0;
+
+nomem:
+        return -ENOMEM;
+}
+
+int
+follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
+                    struct page **pages, struct vm_area_struct **vmas,
+                    unsigned long *position, int *length, int i)
+{
+        unsigned long vpfn, vaddr = *position;
+        int remainder = *length;
+
+        WARN_ON(!is_vm_hugetlb_page(vma));
+
+        vpfn = vaddr/PAGE_SIZE;
+        while (vaddr < vma->vm_end && remainder) {
+
+                if (pages) {
+                        pte_t *pte;
+                        struct page *page;
+
+                        pte = huge_pte_offset(mm, vaddr);
+
+                        /* 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));
+
+                        get_page(page);
+                        pages[i] = page;
+                }
+
+                if (vmas)
+                        vmas[i] = vma;
+
+                vaddr += PAGE_SIZE;
+                ++vpfn;
+                --remainder;
+                ++i;
+        }
+
+        *length = remainder;
+        *position = vaddr;
+
+        return i;
+}
+
+#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
+
+void unmap_hugepage_range(struct vm_area_struct *vma,
+                unsigned long start, unsigned long end)
+{
+        struct mm_struct *mm = vma->vm_mm;
+        unsigned long address;
+        pte_t pte, *ptep;
+        struct page *page;
+
+        BUG_ON(start & (HPAGE_SIZE - 1));
+        BUG_ON(end & (HPAGE_SIZE - 1));
+
+        for (address = start; address < end; address += HPAGE_SIZE) {
+                ptep = huge_pte_offset(mm, address);
+                if (!ptep)
+                        continue;
+                pte = ptep_get_and_clear(mm, address, ptep);
+                if (pte_none(pte))
+                        continue;
+                page = pte_page(pte);
+                put_page(page);
+        }
+        add_mm_counter(mm ,rss, -((end - start) >> PAGE_SHIFT));
+        flush_tlb_range(vma, start, end);
+}
+
+int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
+{
+        struct mm_struct *mm = current->mm;
+        unsigned long addr;
+        int ret = 0;
+
+        BUG_ON(vma->vm_start & ~HPAGE_MASK);
+        BUG_ON(vma->vm_end & ~HPAGE_MASK);
+
+        spin_lock(&mm->page_table_lock);
+        for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
+                unsigned long idx;
+                pte_t *pte = huge_pte_alloc(mm, addr);
+                struct page *page;
+
+                if (!pte) {
+                        ret = -ENOMEM;
+                        goto out;
+                }
+
+                if (!pte_none(*pte)) {
+                        pmd_t *pmd = (pmd_t *) pte;
+
+                        page = pmd_page(*pmd);
+                        pmd_clear(pmd);
+                        mm->nr_ptes--;
+                        dec_page_state(nr_page_table_pages);
+                        page_cache_release(page);
+                }
+
+                idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
+                        + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
+                page = find_get_page(mapping, idx);
+                if (!page) {
+                        /* charge the fs quota first */
+                        if (hugetlb_get_quota(mapping)) {
+                                ret = -ENOMEM;
+                                goto out;
+                        }
+                        page = alloc_huge_page();
+                        if (!page) {
+                                hugetlb_put_quota(mapping);
+                                ret = -ENOMEM;
+                                goto out;
+                        }
+                        ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
+                        if (! ret) {
+                                unlock_page(page);
+                        } else {
+                                hugetlb_put_quota(mapping);
+                                free_huge_page(page);
+                                goto out;
+                        }
+                }
+                set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE);
+        }
+out:
+        spin_unlock(&mm->page_table_lock);
+        return ret;
+}
+
+/* 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;
+
+        start_addr = mm->free_area_cache;
+
+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;
+                                goto full_search;
+                        }
+                        return -ENOMEM;
+                }
+                if (!vma || addr + len <= vma->vm_start) {
+                        mm->free_area_cache = addr + len;
+                        return 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;
+        int first_time = 1;
+
+        /* don't allow allocations above current base */
+        if (mm->free_area_cache > base)
+                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 */
+                        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;
+
+                /* 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;
+                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;
+        addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
+                        len, pgoff, flags);
+
+        /*
+         * Restore the topdown base:
+         */
+        mm->free_area_cache = base;
+
+        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 (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*/
+