From: Lance Yang ioworker0@gmail.com
mainline inclusion from mainline-v6.10-rc1 commit 89e86854fb0aa6e20c0f3d88285fa9cedef4f4e0 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IAIHQO
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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The per-pte get_and_clear/modify/set approach would result in unfolding/refolding for contpte mappings on arm64. So we need to override clear_young_dirty_ptes() for arm64 to avoid it.
Link: https://lkml.kernel.org/r/20240418134435.6092-3-ioworker0@gmail.com Signed-off-by: Lance Yang ioworker0@gmail.com Suggested-by: Barry Song 21cnbao@gmail.com Suggested-by: Ryan Roberts ryan.roberts@arm.com Reviewed-by: Ryan Roberts ryan.roberts@arm.com Cc: David Hildenbrand david@redhat.com Cc: Jeff Xie xiehuan09@gmail.com Cc: Kefeng Wang wangkefeng.wang@huawei.com Cc: Michal Hocko mhocko@suse.com Cc: Minchan Kim minchan@kernel.org Cc: Muchun Song songmuchun@bytedance.com Cc: Peter Xu peterx@redhat.com Cc: Yang Shi shy828301@gmail.com Cc: Yin Fengwei fengwei.yin@intel.com Cc: Zach O'Keefe zokeefe@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Liu Shixin liushixin2@huawei.com --- arch/arm64/include/asm/pgtable.h | 55 ++++++++++++++++++++++++++++++++ arch/arm64/mm/contpte.c | 29 +++++++++++++++++ 2 files changed, 84 insertions(+)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 8d68d00de0a4..e4d6593dfa66 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -1036,6 +1036,46 @@ static inline void __wrprotect_ptes(struct mm_struct *mm, unsigned long address, __ptep_set_wrprotect(mm, address, ptep); }
+static inline void __clear_young_dirty_pte(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t pte, cydp_t flags) +{ + pte_t old_pte; + + do { + old_pte = pte; + + if (flags & CYDP_CLEAR_YOUNG) + pte = pte_mkold(pte); + if (flags & CYDP_CLEAR_DIRTY) + pte = pte_mkclean(pte); + + pte_val(pte) = cmpxchg_relaxed(&pte_val(*ptep), + pte_val(old_pte), pte_val(pte)); + } while (pte_val(pte) != pte_val(old_pte)); +} + +static inline void __clear_young_dirty_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr, cydp_t flags) +{ + pte_t pte; + + for (;;) { + pte = __ptep_get(ptep); + + if (flags == (CYDP_CLEAR_YOUNG | CYDP_CLEAR_DIRTY)) + __set_pte(ptep, pte_mkclean(pte_mkold(pte))); + else + __clear_young_dirty_pte(vma, addr, ptep, pte, flags); + + if (--nr == 0) + break; + ptep++; + addr += PAGE_SIZE; + } +} + #ifdef CONFIG_TRANSPARENT_HUGEPAGE #define __HAVE_ARCH_PMDP_SET_WRPROTECT static inline void pmdp_set_wrprotect(struct mm_struct *mm, @@ -1204,6 +1244,9 @@ extern void contpte_wrprotect_ptes(struct mm_struct *mm, unsigned long addr, extern int contpte_ptep_set_access_flags(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, pte_t entry, int dirty); +extern void contpte_clear_young_dirty_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr, cydp_t flags);
static __always_inline void contpte_try_fold(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte) @@ -1428,6 +1471,17 @@ static inline int ptep_set_access_flags(struct vm_area_struct *vma, return contpte_ptep_set_access_flags(vma, addr, ptep, entry, dirty); }
+#define clear_young_dirty_ptes clear_young_dirty_ptes +static inline void clear_young_dirty_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr, cydp_t flags) +{ + if (likely(nr == 1 && !pte_cont(__ptep_get(ptep)))) + __clear_young_dirty_ptes(vma, addr, ptep, nr, flags); + else + contpte_clear_young_dirty_ptes(vma, addr, ptep, nr, flags); +} + #else /* CONFIG_ARM64_CONTPTE */
#define ptep_get __ptep_get @@ -1447,6 +1501,7 @@ static inline int ptep_set_access_flags(struct vm_area_struct *vma, #define wrprotect_ptes __wrprotect_ptes #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS #define ptep_set_access_flags __ptep_set_access_flags +#define clear_young_dirty_ptes __clear_young_dirty_ptes
#endif /* CONFIG_ARM64_CONTPTE */
diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c index 1b64b4c3f8bf..9f9486de0004 100644 --- a/arch/arm64/mm/contpte.c +++ b/arch/arm64/mm/contpte.c @@ -361,6 +361,35 @@ void contpte_wrprotect_ptes(struct mm_struct *mm, unsigned long addr, } EXPORT_SYMBOL_GPL(contpte_wrprotect_ptes);
+void contpte_clear_young_dirty_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + unsigned int nr, cydp_t flags) +{ + /* + * We can safely clear access/dirty without needing to unfold from + * the architectures perspective, even when contpte is set. If the + * range starts or ends midway through a contpte block, we can just + * expand to include the full contpte block. While this is not + * exactly what the core-mm asked for, it tracks access/dirty per + * folio, not per page. And since we only create a contpte block + * when it is covered by a single folio, we can get away with + * clearing access/dirty for the whole block. + */ + unsigned long start = addr; + unsigned long end = start + nr; + + if (pte_cont(__ptep_get(ptep + nr - 1))) + end = ALIGN(end, CONT_PTE_SIZE); + + if (pte_cont(__ptep_get(ptep))) { + start = ALIGN_DOWN(start, CONT_PTE_SIZE); + ptep = contpte_align_down(ptep); + } + + __clear_young_dirty_ptes(vma, start, ptep, end - start, flags); +} +EXPORT_SYMBOL_GPL(contpte_clear_young_dirty_ptes); + int contpte_ptep_set_access_flags(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, pte_t entry, int dirty)