From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Subject: powerpc/mm/autonuma: switch ppc64 to its own implementation of saved write 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. [aneesh.kumar@xxxxxxxxxxxxxxxxxx: v3] Link: http://lkml.kernel.org/r/1487498625-10891-4-git-send-email-aneesh.kumar@xxxxxxxxxxxxxxxxxx Link: http://lkml.kernel.org/r/1487050314-3892-3-git-send-email-aneesh.kumar@xxxxxxxxxxxxxxxxxx Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Acked-by: Michael Neuling <mikey@xxxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Michael Ellerman <michaele@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/powerpc/include/asm/book3s/64/pgtable.h | 52 ++++++++++++++--- 1 file changed, 45 insertions(+), 7 deletions(-) diff -puN arch/powerpc/include/asm/book3s/64/pgtable.h~powerpc-mm-autonuma-switch-ppc64-to-its-own-implementeation-of-saved-write arch/powerpc/include/asm/book3s/64/pgtable.h --- a/arch/powerpc/include/asm/book3s/64/pgtable.h~powerpc-mm-autonuma-switch-ppc64-to-its-own-implementeation-of-saved-write +++ a/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 <linux/mmdebug.h> +#endif /* * Common bits between hash and Radix page table */ @@ -434,15 +437,47 @@ static inline pte_t pte_clear_soft_dirty #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 */ @@ -873,6 +908,8 @@ static inline pte_t *pmdp_ptep(pmd_t *pm #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)) @@ -889,6 +926,7 @@ 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); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
