106 строки
2.7 KiB
C
106 строки
2.7 KiB
C
/*
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* Copyright (C) 2006 Hollis Blanchard <hollisb@us.ibm.com>, IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/mm.h>
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static unsigned long kernel_virtual_offset;
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static int is_xencomm_initialized;
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/* for xen early printk. It uses console io hypercall which uses xencomm.
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* However early printk may use it before xencomm initialization.
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*/
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int
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xencomm_is_initialized(void)
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{
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return is_xencomm_initialized;
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}
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void
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xencomm_initialize(void)
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{
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kernel_virtual_offset = KERNEL_START - ia64_tpa(KERNEL_START);
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is_xencomm_initialized = 1;
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}
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/* Translate virtual address to physical address. */
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unsigned long
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xencomm_vtop(unsigned long vaddr)
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{
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struct page *page;
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struct vm_area_struct *vma;
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if (vaddr == 0)
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return 0UL;
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if (REGION_NUMBER(vaddr) == 5) {
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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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pte_t *ptep;
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/* On ia64, TASK_SIZE refers to current. It is not initialized
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during boot.
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Furthermore the kernel is relocatable and __pa() doesn't
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work on addresses. */
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if (vaddr >= KERNEL_START
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&& vaddr < (KERNEL_START + KERNEL_TR_PAGE_SIZE))
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return vaddr - kernel_virtual_offset;
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/* In kernel area -- virtually mapped. */
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pgd = pgd_offset_k(vaddr);
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if (pgd_none(*pgd) || pgd_bad(*pgd))
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return ~0UL;
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pud = pud_offset(pgd, vaddr);
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if (pud_none(*pud) || pud_bad(*pud))
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return ~0UL;
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pmd = pmd_offset(pud, vaddr);
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if (pmd_none(*pmd) || pmd_bad(*pmd))
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return ~0UL;
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ptep = pte_offset_kernel(pmd, vaddr);
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if (!ptep)
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return ~0UL;
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return (pte_val(*ptep) & _PFN_MASK) | (vaddr & ~PAGE_MASK);
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}
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if (vaddr > TASK_SIZE) {
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/* percpu variables */
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if (REGION_NUMBER(vaddr) == 7 &&
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REGION_OFFSET(vaddr) >= (1ULL << IA64_MAX_PHYS_BITS))
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ia64_tpa(vaddr);
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/* kernel address */
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return __pa(vaddr);
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}
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/* XXX double-check (lack of) locking */
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vma = find_extend_vma(current->mm, vaddr);
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if (!vma)
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return ~0UL;
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/* We assume the page is modified. */
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page = follow_page(vma, vaddr, FOLL_WRITE | FOLL_TOUCH);
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if (!page)
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return ~0UL;
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return (page_to_pfn(page) << PAGE_SHIFT) | (vaddr & ~PAGE_MASK);
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}
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