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Subject[PATCH] mm/memory.c: Remove pte_sw_mkyoung()
Date
Commit 83d116c53058 ("mm: fix double page fault on arm64 if PTE_AF
is cleared") introduced arch_faults_on_old_pte() helper to identify
platforms that don't set page access bit in HW and require a page
fault to set it.

Commit 44bf431b47b4 ("mm/memory.c: Add memory read privilege on page
fault handling") added pte_sw_mkyoung() which is yet another way to
manage platforms that don't set page access bit in HW and require a
page fault to set it.

Remove that pte_sw_mkyoung() helper and use the already existing
arch_faults_on_old_pte() helper together with pte_mkyoung() instead.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/mips/include/asm/pgtable.h | 2 --
include/linux/pgtable.h | 16 ----------------
mm/memory.c | 9 ++++++---
3 files changed, 6 insertions(+), 21 deletions(-)

diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 4f9c37616d42..3275495adccb 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -406,8 +406,6 @@ static inline pte_t pte_mkyoung(pte_t pte)
return pte;
}

-#define pte_sw_mkyoung pte_mkyoung
-
#ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
static inline int pte_huge(pte_t pte) { return pte_val(pte) & _PAGE_HUGE; }

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 8fcdfa52eb4b..70d04931dff4 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -424,22 +424,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
}
#endif

-/*
- * On some architectures hardware does not set page access bit when accessing
- * memory page, it is responsibilty of software setting this bit. It brings
- * out extra page fault penalty to track page access bit. For optimization page
- * access bit can be set during all page fault flow on these arches.
- * To be differentiate with macro pte_mkyoung, this macro is used on platforms
- * where software maintains page access bit.
- */
-#ifndef pte_sw_mkyoung
-static inline pte_t pte_sw_mkyoung(pte_t pte)
-{
- return pte;
-}
-#define pte_sw_mkyoung pte_sw_mkyoung
-#endif
-
#ifndef pte_savedwrite
#define pte_savedwrite pte_write
#endif
diff --git a/mm/memory.c b/mm/memory.c
index feff48e1465a..46fab785f7b3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2890,7 +2890,8 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
}
flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
entry = mk_pte(new_page, vma->vm_page_prot);
- entry = pte_sw_mkyoung(entry);
+ if (arch_faults_on_old_pte())
+ entry = pte_mkyoung(entry);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);

/*
@@ -3548,7 +3549,8 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
__SetPageUptodate(page);

entry = mk_pte(page, vma->vm_page_prot);
- entry = pte_sw_mkyoung(entry);
+ if (arch_faults_on_old_pte())
+ entry = pte_mkyoung(entry);
if (vma->vm_flags & VM_WRITE)
entry = pte_mkwrite(pte_mkdirty(entry));

@@ -3824,7 +3826,8 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct page *page)

flush_icache_page(vma, page);
entry = mk_pte(page, vma->vm_page_prot);
- entry = pte_sw_mkyoung(entry);
+ if (arch_faults_on_old_pte())
+ entry = pte_mkyoung(entry);
if (write)
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
/* copy-on-write page */
--
2.25.0
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