Messages in this thread Patch in this message | | | From | Christophe Leroy <> | Subject | [PATCH 2/4] powerpc32: properly clear page table when 0 is not a good default PTE value | Date | Wed, 10 Dec 2014 19:00:37 +0100 (CET) |
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Some HW invert some PTE bits. In some case, __pte(0) is not 0 so the PTEs shall be properly set prior to being used.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
--- arch/powerpc/mm/pgtable_32.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c index a349089..71a2821 100644 --- a/arch/powerpc/mm/pgtable_32.c +++ b/arch/powerpc/mm/pgtable_32.c @@ -96,6 +96,14 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd) #endif } +static inline void pte_alloc_clear(pte_t *pte) +{ + int i; + + for (i = 0; i < PTRS_PER_PTE; i++) + pte[i] = __pte(0); +} + __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) { pte_t *pte; @@ -109,18 +117,24 @@ __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long add if (pte) clear_page(pte); } + if (pte && !pte_none(*pte)) + pte_alloc_clear(pte); return pte; } pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address) { struct page *ptepage; + pte_t *pte; gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO; ptepage = alloc_pages(flags, 0); if (!ptepage) return NULL; + pte = (pte_t *)pfn_to_kaddr(page_to_pfn(ptepage)); + if (!pte_none(*pte)) + pte_alloc_clear(pte); if (!pgtable_page_ctor(ptepage)) { __free_page(ptepage); return NULL; -- 2.1.0
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