278 lines
6.4 KiB
C
278 lines
6.4 KiB
C
/*
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* IA-32 Huge TLB Page Support for Kernel.
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*
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* Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
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*/
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#include <linux/config.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/pagemap.h>
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#include <linux/smp_lock.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include <linux/sysctl.h>
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#include <asm/mman.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgd;
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pud_t *pud;
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pte_t *pte = NULL;
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pgd = pgd_offset(mm, addr);
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pud = pud_alloc(mm, pgd, addr);
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if (pud)
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pte = (pte_t *) pmd_alloc(mm, pud, addr);
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BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
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return pte;
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}
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pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd = NULL;
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pgd = pgd_offset(mm, addr);
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if (pgd_present(*pgd)) {
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pud = pud_offset(pgd, addr);
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if (pud_present(*pud))
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pmd = pmd_offset(pud, addr);
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}
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return (pte_t *) pmd;
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}
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#if 0 /* This is just for testing */
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struct page *
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follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
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{
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unsigned long start = address;
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int length = 1;
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int nr;
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struct page *page;
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struct vm_area_struct *vma;
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vma = find_vma(mm, addr);
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if (!vma || !is_vm_hugetlb_page(vma))
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return ERR_PTR(-EINVAL);
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pte = huge_pte_offset(mm, address);
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/* hugetlb should be locked, and hence, prefaulted */
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WARN_ON(!pte || pte_none(*pte));
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page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
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WARN_ON(!PageCompound(page));
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return page;
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}
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int pmd_huge(pmd_t pmd)
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{
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return 0;
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}
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struct page *
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follow_huge_pmd(struct mm_struct *mm, unsigned long address,
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pmd_t *pmd, int write)
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{
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return NULL;
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}
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#else
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struct page *
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follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
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{
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return ERR_PTR(-EINVAL);
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}
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int pmd_huge(pmd_t pmd)
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{
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return !!(pmd_val(pmd) & _PAGE_PSE);
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}
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struct page *
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follow_huge_pmd(struct mm_struct *mm, unsigned long address,
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pmd_t *pmd, int write)
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{
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struct page *page;
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page = pte_page(*(pte_t *)pmd);
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if (page)
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page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
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return page;
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}
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#endif
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/* x86_64 also uses this file */
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#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
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static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
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unsigned long addr, unsigned long len,
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unsigned long pgoff, unsigned long flags)
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{
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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unsigned long start_addr;
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if (len > mm->cached_hole_size) {
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start_addr = mm->free_area_cache;
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} else {
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start_addr = TASK_UNMAPPED_BASE;
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mm->cached_hole_size = 0;
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}
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full_search:
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addr = ALIGN(start_addr, HPAGE_SIZE);
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for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
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/* At this point: (!vma || addr < vma->vm_end). */
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if (TASK_SIZE - len < addr) {
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/*
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* Start a new search - just in case we missed
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* some holes.
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*/
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if (start_addr != TASK_UNMAPPED_BASE) {
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start_addr = TASK_UNMAPPED_BASE;
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mm->cached_hole_size = 0;
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goto full_search;
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}
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return -ENOMEM;
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}
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if (!vma || addr + len <= vma->vm_start) {
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mm->free_area_cache = addr + len;
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return addr;
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}
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if (addr + mm->cached_hole_size < vma->vm_start)
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mm->cached_hole_size = vma->vm_start - addr;
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addr = ALIGN(vma->vm_end, HPAGE_SIZE);
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}
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}
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static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
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unsigned long addr0, unsigned long len,
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unsigned long pgoff, unsigned long flags)
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{
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma, *prev_vma;
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unsigned long base = mm->mmap_base, addr = addr0;
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unsigned long largest_hole = mm->cached_hole_size;
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int first_time = 1;
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/* don't allow allocations above current base */
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if (mm->free_area_cache > base)
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mm->free_area_cache = base;
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if (len <= largest_hole) {
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largest_hole = 0;
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mm->free_area_cache = base;
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}
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try_again:
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/* make sure it can fit in the remaining address space */
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if (mm->free_area_cache < len)
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goto fail;
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/* either no address requested or cant fit in requested address hole */
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addr = (mm->free_area_cache - len) & HPAGE_MASK;
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do {
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/*
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* Lookup failure means no vma is above this address,
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* i.e. return with success:
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*/
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if (!(vma = find_vma_prev(mm, addr, &prev_vma)))
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return addr;
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/*
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* new region fits between prev_vma->vm_end and
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* vma->vm_start, use it:
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*/
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if (addr + len <= vma->vm_start &&
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(!prev_vma || (addr >= prev_vma->vm_end))) {
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/* remember the address as a hint for next time */
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mm->cached_hole_size = largest_hole;
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return (mm->free_area_cache = addr);
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} else {
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/* pull free_area_cache down to the first hole */
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if (mm->free_area_cache == vma->vm_end) {
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mm->free_area_cache = vma->vm_start;
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mm->cached_hole_size = largest_hole;
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}
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}
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/* remember the largest hole we saw so far */
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if (addr + largest_hole < vma->vm_start)
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largest_hole = vma->vm_start - addr;
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/* try just below the current vma->vm_start */
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addr = (vma->vm_start - len) & HPAGE_MASK;
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} while (len <= vma->vm_start);
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fail:
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/*
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* if hint left us with no space for the requested
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* mapping then try again:
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*/
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if (first_time) {
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mm->free_area_cache = base;
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largest_hole = 0;
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first_time = 0;
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goto try_again;
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}
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/*
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* A failed mmap() very likely causes application failure,
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* so fall back to the bottom-up function here. This scenario
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* can happen with large stack limits and large mmap()
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* allocations.
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*/
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mm->free_area_cache = TASK_UNMAPPED_BASE;
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mm->cached_hole_size = ~0UL;
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addr = hugetlb_get_unmapped_area_bottomup(file, addr0,
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len, pgoff, flags);
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/*
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* Restore the topdown base:
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*/
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mm->free_area_cache = base;
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mm->cached_hole_size = ~0UL;
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return addr;
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}
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unsigned long
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hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
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unsigned long len, unsigned long pgoff, unsigned long flags)
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{
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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if (len & ~HPAGE_MASK)
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return -EINVAL;
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if (len > TASK_SIZE)
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return -ENOMEM;
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if (addr) {
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addr = ALIGN(addr, HPAGE_SIZE);
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vma = find_vma(mm, addr);
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if (TASK_SIZE - len >= addr &&
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(!vma || addr + len <= vma->vm_start))
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return addr;
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}
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if (mm->get_unmapped_area == arch_get_unmapped_area)
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return hugetlb_get_unmapped_area_bottomup(file, addr, len,
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pgoff, flags);
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else
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return hugetlb_get_unmapped_area_topdown(file, addr, len,
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pgoff, flags);
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}
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#endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/
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