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Violators will be prosecuted for from ; Sun, 19 Feb 2017 03:04:28 -0700 From: "Aneesh Kumar K.V" Subject: [PATCH V3 3/3] powerpc/mm/autonuma: Switch ppc64 to its own implementeation of saved write Date: Sun, 19 Feb 2017 15:33:45 +0530 In-Reply-To: <1487498625-10891-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1487498625-10891-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Message-Id: <1487498625-10891-4-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, Rik van Riel , Mel Gorman , paulus@ozlabs.org, benh@kernel.crashing.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, "Aneesh Kumar K.V" With this our protnone becomes a present pte with READ/WRITE/EXEC bit cleared. By default we also set _PAGE_PRIVILEGED on such pte. This is now used to help us identify a protnone pte that as saved write bit. For such pte, we will clear the _PAGE_PRIVILEGED bit. The pte still remain non-accessible from both user and kernel. Acked-By: Michael Neuling Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/include/asm/book3s/64/pgtable.h | 52 ++++++++++++++++++++++++---- 1 file changed, 45 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index 6a55bbe91556..d87bee85fc44 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -1,6 +1,9 @@ #ifndef _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ #define _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ +#ifndef __ASSEMBLY__ +#include +#endif /* * Common bits between hash and Radix page table */ @@ -428,15 +431,47 @@ static inline pte_t pte_clear_soft_dirty(pte_t pte) #endif /* CONFIG_HAVE_ARCH_SOFT_DIRTY */ #ifdef CONFIG_NUMA_BALANCING -/* - * These work without NUMA balancing but the kernel does not care. See the - * comment in include/asm-generic/pgtable.h . On powerpc, this will only - * work for user pages and always return true for kernel pages. - */ static inline int pte_protnone(pte_t pte) { - return (pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_PRIVILEGED)) == - cpu_to_be64(_PAGE_PRESENT | _PAGE_PRIVILEGED); + return (pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_PTE | _PAGE_RWX)) == + cpu_to_be64(_PAGE_PRESENT | _PAGE_PTE); +} + +#define pte_mk_savedwrite pte_mk_savedwrite +static inline pte_t pte_mk_savedwrite(pte_t pte) +{ + /* + * Used by Autonuma subsystem to preserve the write bit + * while marking the pte PROT_NONE. Only allow this + * on PROT_NONE pte + */ + VM_BUG_ON((pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_RWX | _PAGE_PRIVILEGED)) != + cpu_to_be64(_PAGE_PRESENT | _PAGE_PRIVILEGED)); + return __pte(pte_val(pte) & ~_PAGE_PRIVILEGED); +} + +#define pte_clear_savedwrite pte_clear_savedwrite +static inline pte_t pte_clear_savedwrite(pte_t pte) +{ + /* + * Used by KSM subsystem to make a protnone pte readonly. + */ + VM_BUG_ON(!pte_protnone(pte)); + return __pte(pte_val(pte) | _PAGE_PRIVILEGED); +} + +#define pte_savedwrite pte_savedwrite +static inline bool pte_savedwrite(pte_t pte) +{ + /* + * Saved write ptes are prot none ptes that doesn't have + * privileged bit sit. We mark prot none as one which has + * present and pviliged bit set and RWX cleared. To mark + * protnone which used to have _PAGE_WRITE set we clear + * the privileged bit. + */ + VM_BUG_ON(!pte_protnone(pte)); + return !(pte_raw(pte) & cpu_to_be64(_PAGE_RWX | _PAGE_PRIVILEGED)); } #endif /* CONFIG_NUMA_BALANCING */ @@ -867,6 +902,8 @@ static inline pte_t *pmdp_ptep(pmd_t *pmd) #define pmd_mkclean(pmd) pte_pmd(pte_mkclean(pmd_pte(pmd))) #define pmd_mkyoung(pmd) pte_pmd(pte_mkyoung(pmd_pte(pmd))) #define pmd_mkwrite(pmd) pte_pmd(pte_mkwrite(pmd_pte(pmd))) +#define pmd_mk_savedwrite(pmd) pte_pmd(pte_mk_savedwrite(pmd_pte(pmd))) +#define pmd_clear_savedwrite(pmd) pte_pmd(pte_clear_savedwrite(pmd_pte(pmd))) #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY #define pmd_soft_dirty(pmd) pte_soft_dirty(pmd_pte(pmd)) @@ -883,6 +920,7 @@ static inline int pmd_protnone(pmd_t pmd) #define __HAVE_ARCH_PMD_WRITE #define pmd_write(pmd) pte_write(pmd_pte(pmd)) +#define pmd_savedwrite(pmd) pte_savedwrite(pmd_pte(pmd)) #ifdef CONFIG_TRANSPARENT_HUGEPAGE extern pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot); -- 2.7.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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