![Naoya Horiguchi](/assets/img/avatar_default.png)
Currently hugepage migration is available for all archs which support pmd-level hugepage, but testing is done only for x86_64 and there're bugs for other archs. So to avoid breaking such archs, this patch limits the availability strictly to x86_64 until developers of other archs get interested in enabling this feature. Simply disabling hugepage migration on non-x86_64 archs is not enough to fix the reported problem where sys_move_pages() hits the BUG_ON() in follow_page(FOLL_GET), so let's fix this by checking if hugepage migration is supported in vma_migratable(). Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Hugh Dickins <hughd@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Miller <davem@davemloft.net> Cc: <stable@vger.kernel.org> [3.12+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
377 lines
9.6 KiB
C
377 lines
9.6 KiB
C
/*
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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*
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* TILE Huge TLB Page Support for Kernel.
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* Taken from i386 hugetlb implementation:
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* Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
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*/
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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/slab.h>
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#include <linux/err.h>
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#include <linux/sysctl.h>
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#include <linux/mman.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/setup.h>
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#ifdef CONFIG_HUGETLB_SUPER_PAGES
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/*
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* Provide an additional huge page size (in addition to the regular default
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* huge page size) if no "hugepagesz" arguments are specified.
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* Note that it must be smaller than the default huge page size so
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* that it's possible to allocate them on demand from the buddy allocator.
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* You can change this to 64K (on a 16K build), 256K, 1M, or 4M,
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* or not define it at all.
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*/
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#define ADDITIONAL_HUGE_SIZE (1024 * 1024UL)
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/* "Extra" page-size multipliers, one per level of the page table. */
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int huge_shift[HUGE_SHIFT_ENTRIES] = {
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#ifdef ADDITIONAL_HUGE_SIZE
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#define ADDITIONAL_HUGE_SHIFT __builtin_ctzl(ADDITIONAL_HUGE_SIZE / PAGE_SIZE)
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[HUGE_SHIFT_PAGE] = ADDITIONAL_HUGE_SHIFT
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#endif
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};
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#endif
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pte_t *huge_pte_alloc(struct mm_struct *mm,
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unsigned long addr, unsigned long sz)
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{
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pgd_t *pgd;
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pud_t *pud;
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addr &= -sz; /* Mask off any low bits in the address. */
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pgd = pgd_offset(mm, addr);
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pud = pud_alloc(mm, pgd, addr);
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#ifdef CONFIG_HUGETLB_SUPER_PAGES
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if (sz >= PGDIR_SIZE) {
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BUG_ON(sz != PGDIR_SIZE &&
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sz != PGDIR_SIZE << huge_shift[HUGE_SHIFT_PGDIR]);
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return (pte_t *)pud;
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} else {
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pmd_t *pmd = pmd_alloc(mm, pud, addr);
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if (sz >= PMD_SIZE) {
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BUG_ON(sz != PMD_SIZE &&
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sz != (PMD_SIZE << huge_shift[HUGE_SHIFT_PMD]));
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return (pte_t *)pmd;
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}
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else {
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if (sz != PAGE_SIZE << huge_shift[HUGE_SHIFT_PAGE])
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panic("Unexpected page size %#lx\n", sz);
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return pte_alloc_map(mm, NULL, pmd, addr);
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}
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}
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#else
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BUG_ON(sz != PMD_SIZE);
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return (pte_t *) pmd_alloc(mm, pud, addr);
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#endif
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}
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static pte_t *get_pte(pte_t *base, int index, int level)
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{
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pte_t *ptep = base + index;
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#ifdef CONFIG_HUGETLB_SUPER_PAGES
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if (!pte_present(*ptep) && huge_shift[level] != 0) {
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unsigned long mask = -1UL << huge_shift[level];
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pte_t *super_ptep = base + (index & mask);
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pte_t pte = *super_ptep;
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if (pte_present(pte) && pte_super(pte))
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ptep = super_ptep;
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}
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#endif
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return ptep;
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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;
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#ifdef CONFIG_HUGETLB_SUPER_PAGES
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pte_t *pte;
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#endif
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/* Get the top-level page table entry. */
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pgd = (pgd_t *)get_pte((pte_t *)mm->pgd, pgd_index(addr), 0);
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/* We don't have four levels. */
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pud = pud_offset(pgd, addr);
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#ifndef __PAGETABLE_PUD_FOLDED
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# error support fourth page table level
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#endif
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if (!pud_present(*pud))
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return NULL;
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/* Check for an L0 huge PTE, if we have three levels. */
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#ifndef __PAGETABLE_PMD_FOLDED
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if (pud_huge(*pud))
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return (pte_t *)pud;
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pmd = (pmd_t *)get_pte((pte_t *)pud_page_vaddr(*pud),
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pmd_index(addr), 1);
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if (!pmd_present(*pmd))
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return NULL;
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#else
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pmd = pmd_offset(pud, addr);
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#endif
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/* Check for an L1 huge PTE. */
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if (pmd_huge(*pmd))
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return (pte_t *)pmd;
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#ifdef CONFIG_HUGETLB_SUPER_PAGES
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/* Check for an L2 huge PTE. */
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pte = get_pte((pte_t *)pmd_page_vaddr(*pmd), pte_index(addr), 2);
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if (!pte_present(*pte))
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return NULL;
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if (pte_super(*pte))
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return pte;
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#endif
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return NULL;
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}
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struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
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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_HUGE_PAGE);
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}
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int pud_huge(pud_t pud)
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{
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return !!(pud_val(pud) & _PAGE_HUGE_PAGE);
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}
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struct page *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 & ~PMD_MASK) >> PAGE_SHIFT);
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return page;
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}
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struct page *follow_huge_pud(struct mm_struct *mm, unsigned long address,
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pud_t *pud, int write)
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{
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struct page *page;
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page = pte_page(*(pte_t *)pud);
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if (page)
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page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
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return page;
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}
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int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
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{
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return 0;
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}
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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 hstate *h = hstate_file(file);
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struct vm_unmapped_area_info info;
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info.flags = 0;
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info.length = len;
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info.low_limit = TASK_UNMAPPED_BASE;
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info.high_limit = TASK_SIZE;
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info.align_mask = PAGE_MASK & ~huge_page_mask(h);
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info.align_offset = 0;
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return vm_unmapped_area(&info);
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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 hstate *h = hstate_file(file);
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struct vm_unmapped_area_info info;
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unsigned long addr;
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info.flags = VM_UNMAPPED_AREA_TOPDOWN;
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info.length = len;
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info.low_limit = PAGE_SIZE;
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info.high_limit = current->mm->mmap_base;
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info.align_mask = PAGE_MASK & ~huge_page_mask(h);
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info.align_offset = 0;
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addr = vm_unmapped_area(&info);
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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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if (addr & ~PAGE_MASK) {
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VM_BUG_ON(addr != -ENOMEM);
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info.flags = 0;
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info.low_limit = TASK_UNMAPPED_BASE;
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info.high_limit = TASK_SIZE;
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addr = vm_unmapped_area(&info);
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}
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return addr;
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}
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unsigned long 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 hstate *h = hstate_file(file);
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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 & ~huge_page_mask(h))
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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 (flags & MAP_FIXED) {
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if (prepare_hugepage_range(file, addr, len))
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return -EINVAL;
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return addr;
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}
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if (addr) {
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addr = ALIGN(addr, huge_page_size(h));
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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 (current->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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#ifdef CONFIG_HUGETLB_SUPER_PAGES
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static __init int __setup_hugepagesz(unsigned long ps)
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{
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int log_ps = __builtin_ctzl(ps);
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int level, base_shift;
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if ((1UL << log_ps) != ps || (log_ps & 1) != 0) {
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pr_warn("Not enabling %ld byte huge pages;"
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" must be a power of four.\n", ps);
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return -EINVAL;
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}
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if (ps > 64*1024*1024*1024UL) {
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pr_warn("Not enabling %ld MB huge pages;"
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" largest legal value is 64 GB .\n", ps >> 20);
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return -EINVAL;
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} else if (ps >= PUD_SIZE) {
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static long hv_jpage_size;
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if (hv_jpage_size == 0)
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hv_jpage_size = hv_sysconf(HV_SYSCONF_PAGE_SIZE_JUMBO);
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if (hv_jpage_size != PUD_SIZE) {
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pr_warn("Not enabling >= %ld MB huge pages:"
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" hypervisor reports size %ld\n",
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PUD_SIZE >> 20, hv_jpage_size);
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return -EINVAL;
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}
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level = 0;
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base_shift = PUD_SHIFT;
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} else if (ps >= PMD_SIZE) {
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level = 1;
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base_shift = PMD_SHIFT;
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} else if (ps > PAGE_SIZE) {
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level = 2;
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base_shift = PAGE_SHIFT;
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} else {
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pr_err("hugepagesz: huge page size %ld too small\n", ps);
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return -EINVAL;
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}
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if (log_ps != base_shift) {
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int shift_val = log_ps - base_shift;
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if (huge_shift[level] != 0) {
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int old_shift = base_shift + huge_shift[level];
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pr_warn("Not enabling %ld MB huge pages;"
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" already have size %ld MB.\n",
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ps >> 20, (1UL << old_shift) >> 20);
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return -EINVAL;
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}
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if (hv_set_pte_super_shift(level, shift_val) != 0) {
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pr_warn("Not enabling %ld MB huge pages;"
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" no hypervisor support.\n", ps >> 20);
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return -EINVAL;
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}
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printk(KERN_DEBUG "Enabled %ld MB huge pages\n", ps >> 20);
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huge_shift[level] = shift_val;
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}
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hugetlb_add_hstate(log_ps - PAGE_SHIFT);
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return 0;
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}
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static bool saw_hugepagesz;
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static __init int setup_hugepagesz(char *opt)
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{
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if (!saw_hugepagesz) {
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saw_hugepagesz = true;
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memset(huge_shift, 0, sizeof(huge_shift));
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}
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return __setup_hugepagesz(memparse(opt, NULL));
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}
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__setup("hugepagesz=", setup_hugepagesz);
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#ifdef ADDITIONAL_HUGE_SIZE
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/*
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* Provide an additional huge page size if no "hugepagesz" args are given.
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* In that case, all the cores have properly set up their hv super_shift
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* already, but we need to notify the hugetlb code to enable the
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* new huge page size from the Linux point of view.
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*/
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static __init int add_default_hugepagesz(void)
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{
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if (!saw_hugepagesz) {
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BUILD_BUG_ON(ADDITIONAL_HUGE_SIZE >= PMD_SIZE ||
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ADDITIONAL_HUGE_SIZE <= PAGE_SIZE);
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BUILD_BUG_ON((PAGE_SIZE << ADDITIONAL_HUGE_SHIFT) !=
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ADDITIONAL_HUGE_SIZE);
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BUILD_BUG_ON(ADDITIONAL_HUGE_SHIFT & 1);
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hugetlb_add_hstate(ADDITIONAL_HUGE_SHIFT);
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}
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return 0;
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}
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arch_initcall(add_default_hugepagesz);
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#endif
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#endif /* CONFIG_HUGETLB_SUPER_PAGES */
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