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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 7/9] mm: Use common huge_ptep_set_access_flags() function for riscv/arm64
Date: Fri,  1 Mar 2024 10:14:53 +0100
Message-Id: <20240301091455.246686-8-alexghiti@rivosinc.com>
In-Reply-To: <20240301091455.246686-1-alexghiti@rivosinc.com>
References: <20240301091455.246686-1-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/mm/hugetlbpage.c | 29 ---------------
 mm/contpte.c                | 74 +++++++++++++++++++++++++++++++++++++
 3 files changed, 74 insertions(+), 94 deletions(-)

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index a2d33cbc7da5..b8abbd5ace4f 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -284,71 +284,6 @@ 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_pte_at(mm, addr, ptep, pfn_pte(pfn, hugeprot));
-
-	return 1;
-}
-
 void huge_ptep_set_wrprotect(struct mm_struct *mm,
 			     unsigned long addr, pte_t *ptep)
 {
diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
index 4c441664db8a..fdb633844d4b 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/mm/contpte.c b/mm/contpte.c
index 8d2ab391e0d8..3b65c49c6d4b 100644
--- a/mm/contpte.c
+++ b/mm/contpte.c
@@ -21,6 +21,7 @@
  * 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)
@@ -156,3 +157,76 @@ 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