From 71ce1ab54a505736786d9c5921e6c2718c7ec535 Mon Sep 17 00:00:00 2001 From: Kinsey Ho Date: Wed, 27 Dec 2023 14:12:01 +0000 Subject: mm/mglru: add CONFIG_ARCH_HAS_HW_PTE_YOUNG Patch series "mm/mglru: Kconfig cleanup", v4. This series is the result of the following discussion: https://lore.kernel.org/47066176-bd93-55dd-c2fa-002299d9e034@linux.ibm.com/ It mainly avoids building the code that walks page tables on CPUs that use it, i.e., those don't support hardware accessed bit. Specifically, it introduces a new Kconfig to guard some of functions added by commit bd74fdaea146 ("mm: multi-gen LRU: support page table walks") on CPUs like POWER9, on which the series was tested. This patch (of 5): Some architectures are able to set the accessed bit in PTEs when PTEs are used as part of linear address translations. Add CONFIG_ARCH_HAS_HW_PTE_YOUNG for such architectures to be able to override arch_has_hw_pte_young(). Link: https://lkml.kernel.org/r/20231227141205.2200125-1-kinseyho@google.com Link: https://lkml.kernel.org/r/20231227141205.2200125-2-kinseyho@google.com Signed-off-by: Kinsey Ho Co-developed-by: Aneesh Kumar K.V Signed-off-by: Aneesh Kumar K.V Tested-by: Donet Tom Acked-by: Yu Zhao Cc: kernel test robot Signed-off-by: Andrew Morton --- arch/Kconfig | 8 ++++++++ arch/arm64/Kconfig | 1 + arch/x86/Kconfig | 1 + arch/x86/include/asm/pgtable.h | 6 ------ include/linux/pgtable.h | 2 +- 5 files changed, 11 insertions(+), 7 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index f4b210ab0612..8c8901f80586 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -1470,6 +1470,14 @@ config DYNAMIC_SIGFRAME config HAVE_ARCH_NODE_DEV_GROUP bool +config ARCH_HAS_HW_PTE_YOUNG + bool + help + Architectures that select this option are capable of setting the + accessed bit in PTE entries when using them as part of linear address + translations. Architectures that require runtime check should select + this option and override arch_has_hw_pte_young(). + config ARCH_HAS_NONLEAF_PMD_YOUNG bool help diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 7b071a00425d..12d611f3da5d 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -36,6 +36,7 @@ config ARM64 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE select ARCH_HAS_PTE_DEVMAP select ARCH_HAS_PTE_SPECIAL + select ARCH_HAS_HW_PTE_YOUNG select ARCH_HAS_SETUP_DMA_OPS select ARCH_HAS_SET_DIRECT_MAP select ARCH_HAS_SET_MEMORY diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 1566748f16c4..04941a1ffc0a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -88,6 +88,7 @@ config X86 select ARCH_HAS_PMEM_API if X86_64 select ARCH_HAS_PTE_DEVMAP if X86_64 select ARCH_HAS_PTE_SPECIAL + select ARCH_HAS_HW_PTE_YOUNG select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 select ARCH_HAS_COPY_MC if X86_64 diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 57bab91bbf50..08b5cb22d9a6 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -1679,12 +1679,6 @@ static inline bool arch_has_pfn_modify_check(void) return boot_cpu_has_bug(X86_BUG_L1TF); } -#define arch_has_hw_pte_young arch_has_hw_pte_young -static inline bool arch_has_hw_pte_young(void) -{ - return true; -} - #define arch_check_zapped_pte arch_check_zapped_pte void arch_check_zapped_pte(struct vm_area_struct *vma, pte_t pte); diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index af7639c3b0a3..9ecc20fa6269 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -375,7 +375,7 @@ static inline bool arch_has_hw_nonleaf_pmd_young(void) */ static inline bool arch_has_hw_pte_young(void) { - return false; + return IS_ENABLED(CONFIG_ARCH_HAS_HW_PTE_YOUNG); } #endif -- cgit v1.2.3