+++ /dev/null
-/*
- * 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*/
-
git.openpandora.org / pandora-kernel.git / blobdiff