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https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
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016b33c495
The implementation of huge_ptep_set_wrprotect() directly calls ptep_set_wrprotect() to mark a hugepte write protected. However this call is not appropriate on ppc64 kernels as this is a small page only implementation. This can lead to the hash not being flushed correctly when a mapping is being converted to COW, allowing processes to continue using the original copy. Currently huge_ptep_set_wrprotect() unconditionally calls ptep_set_wrprotect(). This is fine on ppc32 kernels as this call is generic. On 64 bit this is implemented as: pte_update(mm, addr, ptep, _PAGE_RW, 0); On ppc64 this last parameter is the page size and is passed directly on to hpte_need_flush(): hpte_need_flush(mm, addr, ptep, old, huge); And this directly affects the page size we pass to flush_hash_page(): flush_hash_page(vaddr, rpte, psize, ssize, 0); As this changes the way the hash is calculated we will flush the wrong pages, potentially leaving live hashes to the original page. Move the definition of huge_ptep_set_wrprotect() to the 32/64 bit specific headers. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
73 lines
1.6 KiB
C
73 lines
1.6 KiB
C
#ifndef _ASM_POWERPC_HUGETLB_H
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#define _ASM_POWERPC_HUGETLB_H
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#include <asm/page.h>
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int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
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unsigned long len);
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void hugetlb_free_pgd_range(struct mmu_gather **tlb, unsigned long addr,
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unsigned long end, unsigned long floor,
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unsigned long ceiling);
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void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep, pte_t pte);
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pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep);
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/*
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* If the arch doesn't supply something else, assume that hugepage
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* size aligned regions are ok without further preparation.
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*/
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static inline int prepare_hugepage_range(unsigned long addr, unsigned long len)
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{
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if (len & ~HPAGE_MASK)
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return -EINVAL;
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if (addr & ~HPAGE_MASK)
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return -EINVAL;
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return 0;
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}
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static inline void hugetlb_prefault_arch_hook(struct mm_struct *mm)
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{
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}
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static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
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unsigned long addr, pte_t *ptep)
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{
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}
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static inline int huge_pte_none(pte_t pte)
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{
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return pte_none(pte);
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}
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static inline pte_t huge_pte_wrprotect(pte_t pte)
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{
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return pte_wrprotect(pte);
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}
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static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
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unsigned long addr, pte_t *ptep,
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pte_t pte, int dirty)
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{
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return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
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}
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static inline pte_t huge_ptep_get(pte_t *ptep)
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{
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return *ptep;
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}
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static inline int arch_prepare_hugepage(struct page *page)
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{
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return 0;
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}
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static inline void arch_release_hugepage(struct page *page)
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{
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}
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#endif /* _ASM_POWERPC_HUGETLB_H */
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