+++ /dev/null
-From 493de1c4b0f2cd909169401da8c445f6c8a7e29d Mon Sep 17 00:00:00 2001
-From: Yu Zhao <yuzhao@google.com>
-Date: Sun, 18 Sep 2022 01:59:59 -0600
-Subject: [PATCH 02/29] mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-
-Some architectures support the accessed bit in non-leaf PMD entries, e.g.,
-x86 sets the accessed bit in a non-leaf PMD entry when using it as part of
-linear address translation [1]. Page table walkers that clear the
-accessed bit may use this capability to reduce their search space.
-
-Note that:
-1. Although an inline function is preferable, this capability is added
- as a configuration option for consistency with the existing macros.
-2. Due to the little interest in other varieties, this capability was
- only tested on Intel and AMD CPUs.
-
-Thanks to the following developers for their efforts [2][3].
- Randy Dunlap <rdunlap@infradead.org>
- Stephen Rothwell <sfr@canb.auug.org.au>
-
-[1]: Intel 64 and IA-32 Architectures Software Developer's Manual
- Volume 3 (June 2021), section 4.8
-[2] https://lore.kernel.org/r/bfdcc7c8-922f-61a9-aa15-7e7250f04af7@infradead.org/
-[3] https://lore.kernel.org/r/20220413151513.5a0d7a7e@canb.auug.org.au/
-
-Link: https://lkml.kernel.org/r/20220918080010.2920238-3-yuzhao@google.com
-Signed-off-by: Yu Zhao <yuzhao@google.com>
-Reviewed-by: Barry Song <baohua@kernel.org>
-Acked-by: Brian Geffon <bgeffon@google.com>
-Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
-Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name>
-Acked-by: Steven Barrett <steven@liquorix.net>
-Acked-by: Suleiman Souhlal <suleiman@google.com>
-Tested-by: Daniel Byrne <djbyrne@mtu.edu>
-Tested-by: Donald Carr <d@chaos-reins.com>
-Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
-Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
-Tested-by: Shuang Zhai <szhai2@cs.rochester.edu>
-Tested-by: Sofia Trinh <sofia.trinh@edi.works>
-Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
-Cc: Andi Kleen <ak@linux.intel.com>
-Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
-Cc: Catalin Marinas <catalin.marinas@arm.com>
-Cc: Dave Hansen <dave.hansen@linux.intel.com>
-Cc: Hillf Danton <hdanton@sina.com>
-Cc: Jens Axboe <axboe@kernel.dk>
-Cc: Johannes Weiner <hannes@cmpxchg.org>
-Cc: Jonathan Corbet <corbet@lwn.net>
-Cc: Linus Torvalds <torvalds@linux-foundation.org>
-Cc: Matthew Wilcox <willy@infradead.org>
-Cc: Mel Gorman <mgorman@suse.de>
-Cc: Miaohe Lin <linmiaohe@huawei.com>
-Cc: Michael Larabel <Michael@MichaelLarabel.com>
-Cc: Michal Hocko <mhocko@kernel.org>
-Cc: Mike Rapoport <rppt@kernel.org>
-Cc: Mike Rapoport <rppt@linux.ibm.com>
-Cc: Peter Zijlstra <peterz@infradead.org>
-Cc: Qi Zheng <zhengqi.arch@bytedance.com>
-Cc: Tejun Heo <tj@kernel.org>
-Cc: Vlastimil Babka <vbabka@suse.cz>
-Cc: Will Deacon <will@kernel.org>
-Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
----
- arch/Kconfig | 8 ++++++++
- arch/x86/Kconfig | 1 +
- arch/x86/include/asm/pgtable.h | 3 ++-
- arch/x86/mm/pgtable.c | 5 ++++-
- include/linux/pgtable.h | 4 ++--
- 5 files changed, 17 insertions(+), 4 deletions(-)
-
---- a/arch/Kconfig
-+++ b/arch/Kconfig
-@@ -1298,6 +1298,14 @@ config ARCH_HAS_ELFCORE_COMPAT
- config ARCH_HAS_PARANOID_L1D_FLUSH
- bool
-
-+config ARCH_HAS_NONLEAF_PMD_YOUNG
-+ bool
-+ help
-+ Architectures that select this option are capable of setting the
-+ accessed bit in non-leaf PMD entries when using them as part of linear
-+ address translations. Page table walkers that clear the accessed bit
-+ may use this capability to reduce their search space.
-+
- source "kernel/gcov/Kconfig"
-
- source "scripts/gcc-plugins/Kconfig"
---- a/arch/x86/Kconfig
-+++ b/arch/x86/Kconfig
-@@ -85,6 +85,7 @@ 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_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2
- select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
- select ARCH_HAS_COPY_MC if X86_64
- select ARCH_HAS_SET_MEMORY
---- a/arch/x86/include/asm/pgtable.h
-+++ b/arch/x86/include/asm/pgtable.h
-@@ -817,7 +817,8 @@ static inline unsigned long pmd_page_vad
-
- static inline int pmd_bad(pmd_t pmd)
- {
-- return (pmd_flags(pmd) & ~_PAGE_USER) != _KERNPG_TABLE;
-+ return (pmd_flags(pmd) & ~(_PAGE_USER | _PAGE_ACCESSED)) !=
-+ (_KERNPG_TABLE & ~_PAGE_ACCESSED);
- }
-
- static inline unsigned long pages_to_mb(unsigned long npg)
---- a/arch/x86/mm/pgtable.c
-+++ b/arch/x86/mm/pgtable.c
-@@ -550,7 +550,7 @@ int ptep_test_and_clear_young(struct vm_
- return ret;
- }
-
--#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG)
- int pmdp_test_and_clear_young(struct vm_area_struct *vma,
- unsigned long addr, pmd_t *pmdp)
- {
-@@ -562,6 +562,9 @@ int pmdp_test_and_clear_young(struct vm_
-
- return ret;
- }
-+#endif
-+
-+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- int pudp_test_and_clear_young(struct vm_area_struct *vma,
- unsigned long addr, pud_t *pudp)
- {
---- a/include/linux/pgtable.h
-+++ b/include/linux/pgtable.h
-@@ -212,7 +212,7 @@ static inline int ptep_test_and_clear_yo
- #endif
-
- #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
--#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG)
- static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
- unsigned long address,
- pmd_t *pmdp)
-@@ -233,7 +233,7 @@ static inline int pmdp_test_and_clear_yo
- BUILD_BUG();
- return 0;
- }
--#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-+#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG */
- #endif
-
- #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
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