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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 9/9] mm: Use common huge_ptep_clear_flush() function for riscv/arm64
Date: Fri,  1 Mar 2024 10:14:55 +0100
Message-Id: <20240301091455.246686-10-alexghiti@rivosinc.com>
In-Reply-To: <20240301091455.246686-1-alexghiti@rivosinc.com>
References: <20240301091455.246686-1-alexghiti@rivosinc.com>
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After some adjustments, both architectures have the same implementation
so move it to the generic code.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/arm64/mm/hugetlbpage.c | 61 -------------------------------------
 arch/riscv/mm/hugetlbpage.c | 51 -------------------------------
 mm/contpte.c                | 15 +++++++++
 3 files changed, 15 insertions(+), 112 deletions(-)

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index d6ddaf282a94..8a273b9816d7 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -119,53 +119,6 @@ int find_num_contig(struct mm_struct *mm, unsigned long addr,
 	return CONT_PTES;
 }
 
-/*
- * Changing some bits of contiguous entries requires us to follow a
- * Break-Before-Make approach, breaking the whole contiguous set
- * before we can change any entries. See ARM DDI 0487A.k_iss10775,
- * "Misprogramming of the Contiguous bit", page D4-1762.
- *
- * This helper performs the break step.
- */
-static pte_t get_clear_contig(struct mm_struct *mm,
-			     unsigned long addr,
-			     pte_t *ptep,
-			     unsigned long pgsize,
-			     unsigned long ncontig)
-{
-	pte_t orig_pte = ptep_get(ptep);
-	unsigned long i;
-
-	for (i = 0; i < ncontig; i++, addr += pgsize, ptep++) {
-		pte_t pte = ptep_get_and_clear(mm, addr, ptep);
-
-		/*
-		 * If HW_AFDBM is enabled, then the HW could turn on
-		 * the dirty or accessed bit for any page in the set,
-		 * so check them all.
-		 */
-		if (pte_dirty(pte))
-			orig_pte = pte_mkdirty(orig_pte);
-
-		if (pte_young(pte))
-			orig_pte = pte_mkyoung(orig_pte);
-	}
-	return orig_pte;
-}
-
-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;
-}
-
 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
 		      unsigned long addr, unsigned long sz)
 {
@@ -284,20 +237,6 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
 	return entry;
 }
 
-pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
-			    unsigned long addr, pte_t *ptep)
-{
-	struct mm_struct *mm = vma->vm_mm;
-	size_t pgsize;
-	int ncontig;
-
-	if (!pte_cont(READ_ONCE(*ptep)))
-		return ptep_clear_flush(vma, addr, ptep);
-
-	ncontig = find_num_contig(mm, addr, ptep, &pgsize);
-	return get_clear_contig_flush(mm, addr, ptep, pgsize, ncontig);
-}
-
 static int __init hugetlbpage_init(void)
 {
 	if (pud_sect_supported())
diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
index e6cbb6fb2904..caf1db6f8f20 100644
--- a/arch/riscv/mm/hugetlbpage.c
+++ b/arch/riscv/mm/hugetlbpage.c
@@ -121,42 +121,6 @@ unsigned long hugetlb_mask_last_page(struct hstate *h)
 	return 0UL;
 }
 
-static pte_t get_clear_contig(struct mm_struct *mm,
-			      unsigned long addr,
-			      pte_t *ptep,
-			      unsigned long pte_num)
-{
-	pte_t orig_pte = ptep_get(ptep);
-	unsigned long i;
-
-	for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++) {
-		pte_t pte = ptep_get_and_clear(mm, addr, ptep);
-
-		if (pte_dirty(pte))
-			orig_pte = pte_mkdirty(orig_pte);
-
-		if (pte_young(pte))
-			orig_pte = pte_mkyoung(orig_pte);
-	}
-
-	return orig_pte;
-}
-
-static pte_t get_clear_contig_flush(struct mm_struct *mm,
-				    unsigned long addr,
-				    pte_t *ptep,
-				    unsigned long pte_num)
-{
-	pte_t orig_pte = get_clear_contig(mm, addr, ptep, pte_num);
-	struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
-	bool valid = !pte_none(orig_pte);
-
-	if (valid)
-		flush_tlb_range(&vma, addr, addr + (PAGE_SIZE * pte_num));
-
-	return orig_pte;
-}
-
 pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
 {
 	unsigned long order;
@@ -173,21 +137,6 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
 	return entry;
 }
 
-pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
-			    unsigned long addr,
-			    pte_t *ptep)
-{
-	pte_t pte = ptep_get(ptep);
-	int pte_num;
-
-	if (!pte_napot(pte))
-		return ptep_clear_flush(vma, addr, ptep);
-
-	pte_num = arch_contpte_get_num_contig(vma->vm_mm, addr, ptep, 0, NULL);
-
-	return get_clear_contig_flush(vma->vm_mm, addr, ptep, pte_num);
-}
-
 static bool is_napot_size(unsigned long size)
 {
 	unsigned long order;
diff --git a/mm/contpte.c b/mm/contpte.c
index f7f26d2cfa23..445e5ebe46b4 100644
--- a/mm/contpte.c
+++ b/mm/contpte.c
@@ -23,6 +23,7 @@
  * huge_ptep_get_and_clear()
  * huge_ptep_set_access_flags()
  * huge_ptep_set_wrprotect()
+ * huge_ptep_clear_flush()
  */
 
 pte_t huge_ptep_get(pte_t *ptep)
@@ -251,3 +252,17 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm,
 
 	set_contptes(mm, addr, ptep, pte, ncontig, pgsize);
 }
+
+pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
+			    unsigned long addr, pte_t *ptep)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	size_t pgsize;
+	int ncontig;
+
+	if (!pte_cont(ptep_get(ptep)))
+		return ptep_clear_flush(vma, addr, ptep);
+
+	ncontig = arch_contpte_get_num_contig(mm, addr, ptep, 0, &pgsize);
+	return get_clear_contig_flush(mm, addr, ptep, pgsize, ncontig);
+}
-- 
2.39.2