Messages in this thread Patch in this message | | | Date | Mon, 26 Jul 2010 12:45:03 -0700 | From | Jeremy Fitzhardinge <> | Subject | [PATCH] x86/hugetlb: use set_pmd for huge pte operations |
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On x86, a huge pte is logically a pte, but structurally a pmd. Among other issues, pmds and ptes overload some flags for multiple uses (PAT vs PSE), so it is necessary to know which structural level a pagetable entry is in order interpret it properly.
When huge pages are used within a paravirtualized system, it is therefore appropriate to use the pmd set of function to operate on them, so that the hypervisor can correctly validate the update.
[ Add fix for 32-bit non-PAE with two-level pagetable - Jeremy ]
Signed-off-by: Dave McCracken<dave.mccracken@oracle.com> Signed-off-by: Jeremy Fitzhardinge<jeremy.fitzhardinge@citrix.com>
diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h index 439a9ac..bf88684 100644 --- a/arch/x86/include/asm/hugetlb.h +++ b/arch/x86/include/asm/hugetlb.h @@ -36,16 +36,28 @@ static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb, free_pgd_range(tlb, addr, end, floor, ceiling); }
+static inline pte_t huge_ptep_get(pte_t *ptep) +{ + return *ptep; +} + static inline void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte) { - set_pte_at(mm, addr, ptep, pte); +#if PAGETABLE_LEVELS>= 3 + set_pmd((pmd_t *)ptep, native_make_pmd(native_pte_val(pte))); +#else + set_pgd((pgd_t *)ptep, native_make_pgd(native_pte_val(pte))); +#endif }
static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { - return ptep_get_and_clear(mm, addr, ptep); + pte_t pte = huge_ptep_get(ptep); + + set_huge_pte_at(mm, addr, ptep, __pte(0)); + return pte; }
static inline void huge_ptep_clear_flush(struct vm_area_struct *vma, @@ -66,19 +78,25 @@ static inline pte_t huge_pte_wrprotect(pte_t pte) static inline void huge_ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { - ptep_set_wrprotect(mm, addr, ptep); + pte_t pte = huge_ptep_get(ptep); + + pte = pte_wrprotect(pte); + set_huge_pte_at(mm, addr, ptep, pte); }
static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, pte_t pte, int dirty) { - return ptep_set_access_flags(vma, addr, ptep, pte, dirty); -} + pte_t oldpte = huge_ptep_get(ptep); + int changed = !pte_same(oldpte, pte);
-static inline pte_t huge_ptep_get(pte_t *ptep) -{ - return *ptep; + if (changed&& dirty) { + set_huge_pte_at(vma->vm_mm, addr, ptep, pte); + flush_tlb_page(vma, addr); + } + + return changed; }
static inline int arch_prepare_hugepage(struct page *page)
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