538 lines
16 KiB
C
538 lines
16 KiB
C
#ifndef _ASM_GENERIC_PGTABLE_H
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#define _ASM_GENERIC_PGTABLE_H
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#ifndef __ASSEMBLY__
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#ifdef CONFIG_MMU
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#include <linux/mm_types.h>
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#include <linux/bug.h>
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#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
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extern int ptep_set_access_flags(struct vm_area_struct *vma,
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unsigned long address, pte_t *ptep,
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pte_t entry, int dirty);
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#endif
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#ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
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extern int pmdp_set_access_flags(struct vm_area_struct *vma,
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unsigned long address, pmd_t *pmdp,
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pmd_t entry, int dirty);
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#endif
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#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
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static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
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unsigned long address,
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pte_t *ptep)
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{
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pte_t pte = *ptep;
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int r = 1;
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if (!pte_young(pte))
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r = 0;
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else
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set_pte_at(vma->vm_mm, address, ptep, pte_mkold(pte));
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return r;
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}
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#endif
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#ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
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unsigned long address,
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pmd_t *pmdp)
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{
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pmd_t pmd = *pmdp;
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int r = 1;
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if (!pmd_young(pmd))
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r = 0;
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else
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set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
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return r;
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}
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#else /* CONFIG_TRANSPARENT_HUGEPAGE */
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static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
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unsigned long address,
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pmd_t *pmdp)
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{
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BUG();
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return 0;
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}
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
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#endif
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#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
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int ptep_clear_flush_young(struct vm_area_struct *vma,
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unsigned long address, pte_t *ptep);
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#endif
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#ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
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int pmdp_clear_flush_young(struct vm_area_struct *vma,
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unsigned long address, pmd_t *pmdp);
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#endif
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#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
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static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
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unsigned long address,
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pte_t *ptep)
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{
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pte_t pte = *ptep;
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pte_clear(mm, address, ptep);
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return pte;
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}
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#endif
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#ifndef __HAVE_ARCH_PMDP_GET_AND_CLEAR
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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static inline pmd_t pmdp_get_and_clear(struct mm_struct *mm,
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unsigned long address,
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pmd_t *pmdp)
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{
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pmd_t pmd = *pmdp;
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pmd_clear(mm, address, pmdp);
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return pmd;
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}
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
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#endif
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#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
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static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
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unsigned long address, pte_t *ptep,
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int full)
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{
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pte_t pte;
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pte = ptep_get_and_clear(mm, address, ptep);
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return pte;
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}
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#endif
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/*
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* Some architectures may be able to avoid expensive synchronization
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* primitives when modifications are made to PTE's which are already
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* not present, or in the process of an address space destruction.
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*/
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#ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
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static inline void pte_clear_not_present_full(struct mm_struct *mm,
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unsigned long address,
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pte_t *ptep,
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int full)
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{
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pte_clear(mm, address, ptep);
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}
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#endif
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#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
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extern pte_t ptep_clear_flush(struct vm_area_struct *vma,
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unsigned long address,
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pte_t *ptep);
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#endif
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#ifndef __HAVE_ARCH_PMDP_CLEAR_FLUSH
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extern pmd_t pmdp_clear_flush(struct vm_area_struct *vma,
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unsigned long address,
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pmd_t *pmdp);
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#endif
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#ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
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struct mm_struct;
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static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
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{
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pte_t old_pte = *ptep;
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set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
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}
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#endif
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#ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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static inline void pmdp_set_wrprotect(struct mm_struct *mm,
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unsigned long address, pmd_t *pmdp)
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{
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pmd_t old_pmd = *pmdp;
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set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
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}
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#else /* CONFIG_TRANSPARENT_HUGEPAGE */
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static inline void pmdp_set_wrprotect(struct mm_struct *mm,
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unsigned long address, pmd_t *pmdp)
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{
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BUG();
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}
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
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#endif
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#ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
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extern void pmdp_splitting_flush(struct vm_area_struct *vma,
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unsigned long address, pmd_t *pmdp);
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#endif
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#ifndef __HAVE_ARCH_PTE_SAME
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static inline int pte_same(pte_t pte_a, pte_t pte_b)
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{
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return pte_val(pte_a) == pte_val(pte_b);
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}
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#endif
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#ifndef __HAVE_ARCH_PMD_SAME
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
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{
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return pmd_val(pmd_a) == pmd_val(pmd_b);
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}
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#else /* CONFIG_TRANSPARENT_HUGEPAGE */
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static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
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{
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BUG();
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return 0;
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}
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
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#endif
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#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
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#define page_test_and_clear_dirty(pfn, mapped) (0)
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#endif
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#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
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#define pte_maybe_dirty(pte) pte_dirty(pte)
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#else
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#define pte_maybe_dirty(pte) (1)
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#endif
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#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
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#define page_test_and_clear_young(pfn) (0)
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#endif
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#ifndef __HAVE_ARCH_PGD_OFFSET_GATE
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#define pgd_offset_gate(mm, addr) pgd_offset(mm, addr)
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#endif
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#ifndef __HAVE_ARCH_MOVE_PTE
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#define move_pte(pte, prot, old_addr, new_addr) (pte)
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#endif
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#ifndef flush_tlb_fix_spurious_fault
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#define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
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#endif
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#ifndef pgprot_noncached
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#define pgprot_noncached(prot) (prot)
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#endif
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#ifndef pgprot_writecombine
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#define pgprot_writecombine pgprot_noncached
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#endif
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/*
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* When walking page tables, get the address of the next boundary,
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* or the end address of the range if that comes earlier. Although no
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* vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
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*/
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#define pgd_addr_end(addr, end) \
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({ unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK; \
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(__boundary - 1 < (end) - 1)? __boundary: (end); \
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})
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#ifndef pud_addr_end
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#define pud_addr_end(addr, end) \
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({ unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK; \
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(__boundary - 1 < (end) - 1)? __boundary: (end); \
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})
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#endif
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#ifndef pmd_addr_end
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#define pmd_addr_end(addr, end) \
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({ unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK; \
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(__boundary - 1 < (end) - 1)? __boundary: (end); \
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})
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#endif
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/*
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* When walking page tables, we usually want to skip any p?d_none entries;
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* and any p?d_bad entries - reporting the error before resetting to none.
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* Do the tests inline, but report and clear the bad entry in mm/memory.c.
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*/
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void pgd_clear_bad(pgd_t *);
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void pud_clear_bad(pud_t *);
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void pmd_clear_bad(pmd_t *);
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static inline int pgd_none_or_clear_bad(pgd_t *pgd)
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{
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if (pgd_none(*pgd))
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return 1;
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if (unlikely(pgd_bad(*pgd))) {
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pgd_clear_bad(pgd);
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return 1;
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}
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return 0;
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}
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static inline int pud_none_or_clear_bad(pud_t *pud)
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{
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if (pud_none(*pud))
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return 1;
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if (unlikely(pud_bad(*pud))) {
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pud_clear_bad(pud);
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return 1;
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}
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return 0;
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}
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static inline int pmd_none_or_clear_bad(pmd_t *pmd)
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{
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if (pmd_none(*pmd))
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return 1;
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if (unlikely(pmd_bad(*pmd))) {
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pmd_clear_bad(pmd);
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return 1;
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}
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return 0;
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}
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static inline pte_t __ptep_modify_prot_start(struct mm_struct *mm,
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unsigned long addr,
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pte_t *ptep)
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{
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/*
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* Get the current pte state, but zero it out to make it
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* non-present, preventing the hardware from asynchronously
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* updating it.
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*/
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return ptep_get_and_clear(mm, addr, ptep);
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}
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static inline void __ptep_modify_prot_commit(struct mm_struct *mm,
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unsigned long addr,
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pte_t *ptep, pte_t pte)
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{
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/*
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* The pte is non-present, so there's no hardware state to
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* preserve.
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*/
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set_pte_at(mm, addr, ptep, pte);
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}
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#ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
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/*
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* Start a pte protection read-modify-write transaction, which
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* protects against asynchronous hardware modifications to the pte.
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* The intention is not to prevent the hardware from making pte
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* updates, but to prevent any updates it may make from being lost.
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*
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* This does not protect against other software modifications of the
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* pte; the appropriate pte lock must be held over the transation.
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*
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* Note that this interface is intended to be batchable, meaning that
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* ptep_modify_prot_commit may not actually update the pte, but merely
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* queue the update to be done at some later time. The update must be
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* actually committed before the pte lock is released, however.
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*/
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static inline pte_t ptep_modify_prot_start(struct mm_struct *mm,
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unsigned long addr,
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pte_t *ptep)
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{
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return __ptep_modify_prot_start(mm, addr, ptep);
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}
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/*
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* Commit an update to a pte, leaving any hardware-controlled bits in
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* the PTE unmodified.
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*/
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static inline void ptep_modify_prot_commit(struct mm_struct *mm,
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unsigned long addr,
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pte_t *ptep, pte_t pte)
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{
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__ptep_modify_prot_commit(mm, addr, ptep, pte);
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}
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#endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
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#endif /* CONFIG_MMU */
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/*
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* A facility to provide lazy MMU batching. This allows PTE updates and
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* page invalidations to be delayed until a call to leave lazy MMU mode
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* is issued. Some architectures may benefit from doing this, and it is
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* beneficial for both shadow and direct mode hypervisors, which may batch
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* the PTE updates which happen during this window. Note that using this
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* interface requires that read hazards be removed from the code. A read
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* hazard could result in the direct mode hypervisor case, since the actual
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* write to the page tables may not yet have taken place, so reads though
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* a raw PTE pointer after it has been modified are not guaranteed to be
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* up to date. This mode can only be entered and left under the protection of
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* the page table locks for all page tables which may be modified. In the UP
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* case, this is required so that preemption is disabled, and in the SMP case,
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* it must synchronize the delayed page table writes properly on other CPUs.
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*/
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#ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
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#define arch_enter_lazy_mmu_mode() do {} while (0)
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#define arch_leave_lazy_mmu_mode() do {} while (0)
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#define arch_flush_lazy_mmu_mode() do {} while (0)
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#endif
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/*
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* A facility to provide batching of the reload of page tables and
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* other process state with the actual context switch code for
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* paravirtualized guests. By convention, only one of the batched
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* update (lazy) modes (CPU, MMU) should be active at any given time,
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* entry should never be nested, and entry and exits should always be
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* paired. This is for sanity of maintaining and reasoning about the
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* kernel code. In this case, the exit (end of the context switch) is
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* in architecture-specific code, and so doesn't need a generic
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* definition.
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*/
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#ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
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#define arch_start_context_switch(prev) do {} while (0)
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#endif
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#ifndef __HAVE_PFNMAP_TRACKING
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/*
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* Interface that can be used by architecture code to keep track of
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* memory type of pfn mappings (remap_pfn_range, vm_insert_pfn)
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*
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* track_pfn_vma_new is called when a _new_ pfn mapping is being established
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* for physical range indicated by pfn and size.
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*/
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static inline int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
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unsigned long pfn, unsigned long size)
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{
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return 0;
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}
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/*
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* Interface that can be used by architecture code to keep track of
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* memory type of pfn mappings (remap_pfn_range, vm_insert_pfn)
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*
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* track_pfn_vma_copy is called when vma that is covering the pfnmap gets
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* copied through copy_page_range().
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*/
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static inline int track_pfn_vma_copy(struct vm_area_struct *vma)
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{
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return 0;
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}
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/*
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* Interface that can be used by architecture code to keep track of
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* memory type of pfn mappings (remap_pfn_range, vm_insert_pfn)
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*
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* untrack_pfn_vma is called while unmapping a pfnmap for a region.
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* untrack can be called for a specific region indicated by pfn and size or
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* can be for the entire vma (in which case size can be zero).
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*/
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static inline void untrack_pfn_vma(struct vm_area_struct *vma,
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unsigned long pfn, unsigned long size)
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{
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}
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#else
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extern int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
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unsigned long pfn, unsigned long size);
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extern int track_pfn_vma_copy(struct vm_area_struct *vma);
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extern void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
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unsigned long size);
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#endif
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#ifdef CONFIG_MMU
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#ifndef CONFIG_TRANSPARENT_HUGEPAGE
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static inline int pmd_trans_huge(pmd_t pmd)
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{
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return 0;
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}
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static inline int pmd_trans_splitting(pmd_t pmd)
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{
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return 0;
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}
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#ifndef __HAVE_ARCH_PMD_WRITE
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static inline int pmd_write(pmd_t pmd)
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{
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BUG();
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return 0;
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}
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#endif /* __HAVE_ARCH_PMD_WRITE */
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
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#ifndef pmd_read_atomic
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static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
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{
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/*
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* Depend on compiler for an atomic pmd read. NOTE: this is
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* only going to work, if the pmdval_t isn't larger than
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* an unsigned long.
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*/
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return *pmdp;
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}
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#endif
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/*
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* This function is meant to be used by sites walking pagetables with
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* the mmap_sem hold in read mode to protect against MADV_DONTNEED and
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* transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
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* into a null pmd and the transhuge page fault can convert a null pmd
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* into an hugepmd or into a regular pmd (if the hugepage allocation
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* fails). While holding the mmap_sem in read mode the pmd becomes
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* stable and stops changing under us only if it's not null and not a
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* transhuge pmd. When those races occurs and this function makes a
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* difference vs the standard pmd_none_or_clear_bad, the result is
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* undefined so behaving like if the pmd was none is safe (because it
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* can return none anyway). The compiler level barrier() is critically
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* important to compute the two checks atomically on the same pmdval.
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*
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* For 32bit kernels with a 64bit large pmd_t this automatically takes
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* care of reading the pmd atomically to avoid SMP race conditions
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* against pmd_populate() when the mmap_sem is hold for reading by the
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* caller (a special atomic read not done by "gcc" as in the generic
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* version above, is also needed when THP is disabled because the page
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* fault can populate the pmd from under us).
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*/
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static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
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{
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pmd_t pmdval = pmd_read_atomic(pmd);
|
|
/*
|
|
* The barrier will stabilize the pmdval in a register or on
|
|
* the stack so that it will stop changing under the code.
|
|
*
|
|
* When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
|
|
* pmd_read_atomic is allowed to return a not atomic pmdval
|
|
* (for example pointing to an hugepage that has never been
|
|
* mapped in the pmd). The below checks will only care about
|
|
* the low part of the pmd with 32bit PAE x86 anyway, with the
|
|
* exception of pmd_none(). So the important thing is that if
|
|
* the low part of the pmd is found null, the high part will
|
|
* be also null or the pmd_none() check below would be
|
|
* confused.
|
|
*/
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
barrier();
|
|
#endif
|
|
if (pmd_none(pmdval))
|
|
return 1;
|
|
if (unlikely(pmd_bad(pmdval))) {
|
|
if (!pmd_trans_huge(pmdval))
|
|
pmd_clear_bad(pmd);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This is a noop if Transparent Hugepage Support is not built into
|
|
* the kernel. Otherwise it is equivalent to
|
|
* pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
|
|
* places that already verified the pmd is not none and they want to
|
|
* walk ptes while holding the mmap sem in read mode (write mode don't
|
|
* need this). If THP is not enabled, the pmd can't go away under the
|
|
* code even if MADV_DONTNEED runs, but if THP is enabled we need to
|
|
* run a pmd_trans_unstable before walking the ptes after
|
|
* split_huge_page_pmd returns (because it may have run when the pmd
|
|
* become null, but then a page fault can map in a THP and not a
|
|
* regular page).
|
|
*/
|
|
static inline int pmd_trans_unstable(pmd_t *pmd)
|
|
{
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
return pmd_none_or_trans_huge_or_clear_bad(pmd);
|
|
#else
|
|
return 0;
|
|
#endif
|
|
}
|
|
|
|
#endif /* CONFIG_MMU */
|
|
|
|
#endif /* !__ASSEMBLY__ */
|
|
|
|
#endif /* _ASM_GENERIC_PGTABLE_H */
|