[PATCH v5 9/9] mm: Use common huge_ptep_clear_flush() function for riscv/arm64

[Alexandre Ghiti <alexghiti@rivosinc.com>]

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/include/asm/hugetlb.h |  3 --
 arch/arm64/mm/hugetlbpage.c      | 60 --------------------------------
 arch/riscv/include/asm/hugetlb.h |  7 +---
 arch/riscv/mm/hugetlbpage.c      | 54 ----------------------------
 include/linux/hugetlb_contpte.h  |  4 +++
 mm/hugetlb_contpte.c             | 14 ++++++++
 6 files changed, 19 insertions(+), 123 deletions(-)

diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
index f568467e8ba2..368600764127 100644
--- a/arch/arm64/include/asm/hugetlb.h
+++ b/arch/arm64/include/asm/hugetlb.h
@@ -35,9 +35,6 @@ static inline void arch_clear_hugetlb_flags(struct folio *folio)
 
 pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags);
 #define arch_make_huge_pte arch_make_huge_pte
-#define __HAVE_ARCH_HUGE_PTEP_CLEAR_FLUSH
-extern pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
-				   unsigned long addr, pte_t *ptep);
 
 void __init arm64_hugetlb_cma_reserve(void);
 
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 17f1ed34356d..08316cf4b104 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -82,52 +82,6 @@ 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 pte, tmp_pte;
-	bool present;
-
-	pte = __ptep_get_and_clear(mm, addr, ptep);
-	present = pte_present(pte);
-	while (--ncontig) {
-		ptep++;
-		addr += pgsize;
-		tmp_pte = __ptep_get_and_clear(mm, addr, ptep);
-		if (present) {
-			if (pte_dirty(tmp_pte))
-				pte = pte_mkdirty(pte);
-			if (pte_young(tmp_pte))
-				pte = pte_mkyoung(pte);
-		}
-	}
-	return 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)
 {
@@ -260,20 +214,6 @@ 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(__ptep_get(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)
 {
 	/*
diff --git a/arch/riscv/include/asm/hugetlb.h b/arch/riscv/include/asm/hugetlb.h
index 4c692dd82779..63c7e4fa342a 100644
--- a/arch/riscv/include/asm/hugetlb.h
+++ b/arch/riscv/include/asm/hugetlb.h
@@ -20,14 +20,9 @@ bool arch_hugetlb_migration_supported(struct hstate *h);
 #endif
 
 #ifdef CONFIG_RISCV_ISA_SVNAPOT
-#define __HAVE_ARCH_HUGE_PTEP_CLEAR_FLUSH
-pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
-			    unsigned long addr, pte_t *ptep);
-
 pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags);
 #define arch_make_huge_pte arch_make_huge_pte
-
-#endif /*CONFIG_RISCV_ISA_SVNAPOT*/
+#endif /* CONFIG_RISCV_ISA_SVNAPOT */
 
 #include <asm-generic/hugetlb.h>
 
diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
index db13f7bcdd54..a6176415432a 100644
--- a/arch/riscv/mm/hugetlbpage.c
+++ b/arch/riscv/mm/hugetlbpage.c
@@ -121,45 +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 ncontig)
-{
-	pte_t pte, tmp_pte;
-	bool present;
-
-	pte = ptep_get_and_clear(mm, addr, ptep);
-	present = pte_present(pte);
-	while (--ncontig) {
-		ptep++;
-		addr += PAGE_SIZE;
-		tmp_pte = ptep_get_and_clear(mm, addr, ptep);
-		if (present) {
-			if (pte_dirty(tmp_pte))
-				pte = pte_mkdirty(pte);
-			if (pte_young(tmp_pte))
-				pte = pte_mkyoung(pte);
-		}
-	}
-	return 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;
@@ -176,21 +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/include/linux/hugetlb_contpte.h b/include/linux/hugetlb_contpte.h
index 9ec8792a2f4d..e217a3412b13 100644
--- a/include/linux/hugetlb_contpte.h
+++ b/include/linux/hugetlb_contpte.h
@@ -32,4 +32,8 @@ extern int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 extern void huge_ptep_set_wrprotect(struct mm_struct *mm,
 				    unsigned long addr, pte_t *ptep);
 
+#define __HAVE_ARCH_HUGE_PTEP_CLEAR_FLUSH
+extern pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
+				   unsigned long addr, pte_t *ptep);
+
 #endif /* _LINUX_HUGETLB_CONTPTE_H */
diff --git a/mm/hugetlb_contpte.c b/mm/hugetlb_contpte.c
index 629878765081..1dc211d6fbe1 100644
--- a/mm/hugetlb_contpte.c
+++ b/mm/hugetlb_contpte.c
@@ -242,3 +242,17 @@ 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