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From: Alexandre Ghiti <alexghiti@rivosinc.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Ryan Roberts <ryan.roberts@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org,
	linux-mm@kvack.org
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Subject: [PATCH RESEND v2 7/9] mm: Use common huge_ptep_set_access_flags() function for riscv/arm64
Date: Wed,  8 May 2024 13:34:17 +0200
Message-Id: <20240508113419.18620-8-alexghiti@rivosinc.com>
In-Reply-To: <20240508113419.18620-1-alexghiti@rivosinc.com>
References: <20240508113419.18620-1-alexghiti@rivosinc.com>
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Both architectures have almost the same implementation:
__cont_access_flags_changed() is also correct on riscv and brings the
same benefits (ie don't do anything if the flags are unchanged).

As in the previous commit, get_clear_contig_flush() is duplicated in both
the arch and the generic codes, it will be removed from the arch code when
the last reference there gets moved to the generic code.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/arm64/mm/hugetlbpage.c      | 65 ---------------------------
 arch/riscv/include/asm/pgtable.h |  7 +--
 arch/riscv/mm/hugetlbpage.c      | 29 ------------
 arch/riscv/mm/pgtable.c          |  6 +--
 mm/contpte.c                     | 75 ++++++++++++++++++++++++++++++++
 5 files changed, 82 insertions(+), 100 deletions(-)

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 5ace4bf7ce35..052a5bf2926c 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -277,71 +277,6 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
 	return entry;
 }
 
-/*
- * huge_ptep_set_access_flags will update access flags (dirty, accesssed)
- * and write permission.
- *
- * For a contiguous huge pte range we need to check whether or not write
- * permission has to change only on the first pte in the set. Then for
- * all the contiguous ptes we need to check whether or not there is a
- * discrepancy between dirty or young.
- */
-static int __cont_access_flags_changed(pte_t *ptep, pte_t pte, int ncontig)
-{
-	int i;
-
-	if (pte_write(pte) != pte_write(__ptep_get(ptep)))
-		return 1;
-
-	for (i = 0; i < ncontig; i++) {
-		pte_t orig_pte = __ptep_get(ptep + i);
-
-		if (pte_dirty(pte) != pte_dirty(orig_pte))
-			return 1;
-
-		if (pte_young(pte) != pte_young(orig_pte))
-			return 1;
-	}
-
-	return 0;
-}
-
-int huge_ptep_set_access_flags(struct vm_area_struct *vma,
-			       unsigned long addr, pte_t *ptep,
-			       pte_t pte, int dirty)
-{
-	int ncontig, i;
-	size_t pgsize = 0;
-	unsigned long pfn = pte_pfn(pte), dpfn;
-	struct mm_struct *mm = vma->vm_mm;
-	pgprot_t hugeprot;
-	pte_t orig_pte;
-
-	if (!pte_cont(pte))
-		return __ptep_set_access_flags(vma, addr, ptep, pte, dirty);
-
-	ncontig = find_num_contig(mm, addr, ptep, &pgsize);
-	dpfn = pgsize >> PAGE_SHIFT;
-
-	if (!__cont_access_flags_changed(ptep, pte, ncontig))
-		return 0;
-
-	orig_pte = get_clear_contig_flush(mm, addr, ptep, pgsize, ncontig);
-
-	/* Make sure we don't lose the dirty or young state */
-	if (pte_dirty(orig_pte))
-		pte = pte_mkdirty(pte);
-
-	if (pte_young(orig_pte))
-		pte = pte_mkyoung(pte);
-
-	hugeprot = pte_pgprot(pte);
-	for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
-		__set_ptes(mm, addr, ptep, pfn_pte(pfn, hugeprot), 1);
-
-	return 1;
-}
-
 void huge_ptep_set_wrprotect(struct mm_struct *mm,
 			     unsigned long addr, pte_t *ptep)
 {
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index d976113a370d..20f62505d0bc 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -652,9 +652,8 @@ static inline void __pte_clear(struct mm_struct *mm,
 	__set_pte_at(mm, ptep, __pte(0));
 }
 
-#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS	/* defined in mm/pgtable.c */
-extern int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address,
-				 pte_t *ptep, pte_t entry, int dirty);
+extern int __ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address,
+				   pte_t *ptep, pte_t entry, int dirty);
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG	/* defined in mm/pgtable.c */
 extern int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long address,
 				     pte_t *ptep);
@@ -703,6 +702,8 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 #define ptep_get_and_clear	__ptep_get_and_clear
 #define pte_clear		__pte_clear
+#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
+#define ptep_set_access_flags	__ptep_set_access_flags
 
 #define pgprot_nx pgprot_nx
 static inline pgprot_t pgprot_nx(pgprot_t _prot)
diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
index a757e0b2f090..a59b776e9c8b 100644
--- a/arch/riscv/mm/hugetlbpage.c
+++ b/arch/riscv/mm/hugetlbpage.c
@@ -173,35 +173,6 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
 	return entry;
 }
 
-int huge_ptep_set_access_flags(struct vm_area_struct *vma,
-			       unsigned long addr,
-			       pte_t *ptep,
-			       pte_t pte,
-			       int dirty)
-{
-	struct mm_struct *mm = vma->vm_mm;
-	size_t pgsize;
-	pte_t orig_pte;
-	int pte_num;
-
-	if (!pte_napot(pte))
-		return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
-
-	pte_num = arch_contpte_get_num_contig(vma->vm_mm, addr, ptep, 0, &pgsize);
-
-	orig_pte = get_clear_contig_flush(mm, addr, ptep, pte_num);
-
-	if (pte_dirty(orig_pte))
-		pte = pte_mkdirty(pte);
-
-	if (pte_young(orig_pte))
-		pte = pte_mkyoung(pte);
-
-	set_ptes(mm, addr, ptep, pte, pte_num);
-
-	return true;
-}
-
 void huge_ptep_set_wrprotect(struct mm_struct *mm,
 			     unsigned long addr,
 			     pte_t *ptep)
diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c
index 533ec9055fa0..e86df7ef193c 100644
--- a/arch/riscv/mm/pgtable.c
+++ b/arch/riscv/mm/pgtable.c
@@ -5,9 +5,9 @@
 #include <linux/kernel.h>
 #include <linux/pgtable.h>
 
-int ptep_set_access_flags(struct vm_area_struct *vma,
-			  unsigned long address, pte_t *ptep,
-			  pte_t entry, int dirty)
+int __ptep_set_access_flags(struct vm_area_struct *vma,
+			    unsigned long address, pte_t *ptep,
+			    pte_t entry, int dirty)
 {
 	if (!pte_same(ptep_get(ptep), entry))
 		__set_pte_at(vma->vm_mm, ptep, entry);
diff --git a/mm/contpte.c b/mm/contpte.c
index 68eb1634b922..9c7a9f250bca 100644
--- a/mm/contpte.c
+++ b/mm/contpte.c
@@ -13,6 +13,7 @@
  *   - __set_ptes()
  *   - __ptep_get_and_clear()
  *   - __pte_clear()
+ *   - __ptep_set_access_flags()
  *   - pte_cont()
  *   - arch_contpte_get_num_contig()
  */
@@ -23,6 +24,7 @@
  *   - set_huge_pte_at()
  *   - huge_pte_clear()
  *   - huge_ptep_get_and_clear()
+ *   - huge_ptep_set_access_flags()
  */
 
 pte_t huge_ptep_get(pte_t *ptep)
@@ -158,3 +160,76 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 
 	return get_clear_contig(mm, addr, ptep, pgsize, ncontig);
 }
+
+/*
+ * huge_ptep_set_access_flags will update access flags (dirty, accesssed)
+ * and write permission.
+ *
+ * For a contiguous huge pte range we need to check whether or not write
+ * permission has to change only on the first pte in the set. Then for
+ * all the contiguous ptes we need to check whether or not there is a
+ * discrepancy between dirty or young.
+ */
+static int __cont_access_flags_changed(pte_t *ptep, pte_t pte, int ncontig)
+{
+	int i;
+
+	if (pte_write(pte) != pte_write(__ptep_get(ptep)))
+		return 1;
+
+	for (i = 0; i < ncontig; i++) {
+		pte_t orig_pte = __ptep_get(ptep + i);
+
+		if (pte_dirty(pte) != pte_dirty(orig_pte))
+			return 1;
+
+		if (pte_young(pte) != pte_young(orig_pte))
+			return 1;
+	}
+
+	return 0;
+}
+
+static pte_t get_clear_contig_flush(struct mm_struct *mm,
+				    unsigned long addr,
+				    pte_t *ptep,
+				    unsigned long pgsize,
+				    unsigned long ncontig)
+{
+	pte_t orig_pte = get_clear_contig(mm, addr, ptep, pgsize, ncontig);
+	struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
+
+	flush_tlb_range(&vma, addr, addr + (pgsize * ncontig));
+	return orig_pte;
+}
+
+int huge_ptep_set_access_flags(struct vm_area_struct *vma,
+			       unsigned long addr, pte_t *ptep,
+			       pte_t pte, int dirty)
+{
+	int ncontig;
+	size_t pgsize = 0;
+	struct mm_struct *mm = vma->vm_mm;
+	pte_t orig_pte;
+
+	if (!pte_cont(pte))
+		return __ptep_set_access_flags(vma, addr, ptep, pte, dirty);
+
+	ncontig = arch_contpte_get_num_contig(vma->vm_mm, addr, ptep, 0, &pgsize);
+
+	if (!__cont_access_flags_changed(ptep, pte, ncontig))
+		return 0;
+
+	orig_pte = get_clear_contig_flush(mm, addr, ptep, pgsize, ncontig);
+
+	/* Make sure we don't lose the dirty or young state */
+	if (pte_dirty(orig_pte))
+		pte = pte_mkdirty(pte);
+
+	if (pte_young(orig_pte))
+		pte = pte_mkyoung(pte);
+
+	set_contptes(mm, addr, ptep, pte, ncontig, pgsize);
+
+	return 1;
+}
-- 
2.39.2