[v3,4/9] mm: Use common set_huge_pte_at() function for riscv/arm64

Commit Message

Alexandre Ghiti Aug. 2, 2024, 3:14 p.m. UTC

After some adjustments, both architectures have the same implementation
so move it to the generic code.

Signed-off-by: Alexandre Ghiti <[e-mail]>
---
 arch/arm64/include/asm/hugetlb.h |  3 --
 arch/arm64/mm/hugetlbpage.c      | 56 -----------------------------
 arch/riscv/include/asm/hugetlb.h |  5 ---
 arch/riscv/include/asm/pgtable.h |  8 +++--
 arch/riscv/mm/hugetlbpage.c      | 62 --------------------------------
 include/linux/hugetlb_contpte.h  |  5 +++
 mm/hugetlb_contpte.c             | 59 ++++++++++++++++++++++++++++++
 7 files changed, 69 insertions(+), 129 deletions(-)

Patch

diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
index 80d25b4eff25..d35093b7ab59 100644
--- a/arch/arm64/include/asm/hugetlb.h
+++ b/arch/arm64/include/asm/hugetlb.h
@@ -27,9 +27,6 @@  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_SET_HUGE_PTE_AT
-extern void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
-			    pte_t *ptep, pte_t pte, unsigned long sz);
 #define __HAVE_ARCH_HUGE_PTEP_SET_ACCESS_FLAGS
 extern int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 				      unsigned long addr, pte_t *ptep,
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 58cb5e06dcb2..c7130d1f07c4 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -145,62 +145,6 @@  static pte_t get_clear_contig_flush(struct mm_struct *mm,
 	return orig_pte;
 }
 
-/*
- * 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 for use cases where the
- * original pte is not needed.
- */
-static void clear_flush(struct mm_struct *mm,
-			     unsigned long addr,
-			     pte_t *ptep,
-			     unsigned long pgsize,
-			     unsigned long ncontig)
-{
-	struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
-	unsigned long i, saddr = addr;
-
-	for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
-		__ptep_get_and_clear(mm, addr, ptep);
-
-	flush_tlb_range(&vma, saddr, addr);
-}
-
-void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
-			    pte_t *ptep, pte_t pte, unsigned long sz)
-{
-	size_t pgsize;
-	int i;
-	int ncontig;
-	unsigned long pfn, dpfn;
-	pgprot_t hugeprot;
-
-	ncontig = arch_contpte_get_num_contig(ptep, sz, &pgsize);
-
-	if (!pte_present(pte)) {
-		for (i = 0; i < ncontig; i++, ptep++, addr += pgsize)
-			__set_ptes(mm, addr, ptep, pte, 1);
-		return;
-	}
-
-	if (!pte_cont(pte)) {
-		__set_ptes(mm, addr, ptep, pte, 1);
-		return;
-	}
-
-	pfn = pte_pfn(pte);
-	dpfn = pgsize >> PAGE_SHIFT;
-	hugeprot = pte_pgprot(pte);
-
-	clear_flush(mm, addr, ptep, pgsize, ncontig);
-
-	for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
-		__set_ptes(mm, addr, ptep, pfn_pte(pfn, hugeprot), 1);
-}
-
 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
 		      unsigned long addr, unsigned long sz)
 {
diff --git a/arch/riscv/include/asm/hugetlb.h b/arch/riscv/include/asm/hugetlb.h
index d9f9bfb84908..28cbf5d761e1 100644
--- a/arch/riscv/include/asm/hugetlb.h
+++ b/arch/riscv/include/asm/hugetlb.h
@@ -24,11 +24,6 @@  bool arch_hugetlb_migration_supported(struct hstate *h);
 void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
 		    pte_t *ptep, unsigned long sz);
 
-#define __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT
-void set_huge_pte_at(struct mm_struct *mm,
-		     unsigned long addr, pte_t *ptep, pte_t pte,
-		     unsigned long sz);
-
 #define __HAVE_ARCH_HUGE_PTEP_GET_AND_CLEAR
 pte_t huge_ptep_get_and_clear(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 412ccebcdee9..46b409e558b3 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -628,9 +628,8 @@  extern int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long addre
 extern int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long address,
 				     pte_t *ptep);
 
-#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
-static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
-				       unsigned long address, pte_t *ptep)
+static inline pte_t __ptep_get_and_clear(struct mm_struct *mm,
+					 unsigned long address, pte_t *ptep)
 {
 	pte_t pte = __pte(atomic_long_xchg((atomic_long_t *)ptep, 0));
 
@@ -730,6 +729,9 @@  static inline pte_t ptep_get(pte_t *ptep)
 #define ptep_get			__ptep_get
 #endif /* CONFIG_RISCV_ISA_SVNAPOT */
 
+#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
+#define ptep_get_and_clear	__ptep_get_and_clear
+
 #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 d51863824540..0ecb2846c3f0 100644
--- a/arch/riscv/mm/hugetlbpage.c
+++ b/arch/riscv/mm/hugetlbpage.c
@@ -173,68 +173,6 @@  pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
 	return entry;
 }
 
-static void clear_flush(struct mm_struct *mm,
-			unsigned long addr,
-			pte_t *ptep,
-			unsigned long pgsize,
-			unsigned long ncontig)
-{
-	struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
-	unsigned long i, saddr = addr;
-
-	for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
-		ptep_get_and_clear(mm, addr, ptep);
-
-	flush_tlb_range(&vma, saddr, addr);
-}
-
-/*
- * When dealing with NAPOT mappings, the privileged specification indicates that
- * "if an update needs to be made, the OS generally should first mark all of the
- * PTEs invalid, then issue SFENCE.VMA instruction(s) covering all 4 KiB regions
- * within the range, [...] then update the PTE(s), as described in Section
- * 4.2.1.". That's the equivalent of the Break-Before-Make approach used by
- * arm64.
- */
-void set_huge_pte_at(struct mm_struct *mm,
-		     unsigned long addr,
-		     pte_t *ptep,
-		     pte_t pte,
-		     unsigned long sz)
-{
-	unsigned long hugepage_shift, pgsize;
-	int i, pte_num;
-
-	if (sz >= PGDIR_SIZE)
-		hugepage_shift = PGDIR_SHIFT;
-	else if (sz >= P4D_SIZE)
-		hugepage_shift = P4D_SHIFT;
-	else if (sz >= PUD_SIZE)
-		hugepage_shift = PUD_SHIFT;
-	else if (sz >= PMD_SIZE)
-		hugepage_shift = PMD_SHIFT;
-	else
-		hugepage_shift = PAGE_SHIFT;
-
-	pte_num = sz >> hugepage_shift;
-	pgsize = 1 << hugepage_shift;
-
-	if (!pte_present(pte)) {
-		for (i = 0; i < pte_num; i++, ptep++, addr += pgsize)
-			set_ptes(mm, addr, ptep, pte, 1);
-		return;
-	}
-
-	if (!pte_napot(pte)) {
-		set_ptes(mm, addr, ptep, pte, 1);
-		return;
-	}
-
-	clear_flush(mm, addr, ptep, pgsize, pte_num);
-
-	set_ptes(mm, addr, ptep, pte, pte_num);
-}
-
 int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 			       unsigned long addr,
 			       pte_t *ptep,
diff --git a/include/linux/hugetlb_contpte.h b/include/linux/hugetlb_contpte.h
index ec4189cd65b8..7acd734a75e8 100644
--- a/include/linux/hugetlb_contpte.h
+++ b/include/linux/hugetlb_contpte.h
@@ -9,4 +9,9 @@ 
 #define __HAVE_ARCH_HUGE_PTEP_GET
 extern pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep);
 
+#define __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT
+extern void set_huge_pte_at(struct mm_struct *mm,
+			    unsigned long addr, pte_t *ptep, pte_t pte,
+			    unsigned long sz);
+
 #endif /* _LINUX_HUGETLB_CONTPTE_H */
diff --git a/mm/hugetlb_contpte.c b/mm/hugetlb_contpte.c
index 0e3ba6f97c58..9a3a376784b0 100644
--- a/mm/hugetlb_contpte.c
+++ b/mm/hugetlb_contpte.c
@@ -10,6 +10,8 @@ 
 /*
  * Any arch that wants to use that needs to define:
  *   - __ptep_get()
+ *   - __set_ptes()
+ *   - __ptep_get_and_clear()
  *   - pte_cont()
  *   - arch_contpte_get_num_contig()
  */
@@ -17,6 +19,7 @@ 
 /*
  * This file implements the following contpte aware API:
  *   - huge_ptep_get()
+ *   - set_huge_pte_at()
  */
 
 pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
@@ -42,3 +45,59 @@  pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 	}
 	return orig_pte;
 }
+
+/*
+ * ARM64: 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.
+ *
+ * RISCV: When dealing with NAPOT mappings, the privileged specification
+ * indicates that "if an update needs to be made, the OS generally should first
+ * mark all of the PTEs invalid, then issue SFENCE.VMA instruction(s) covering
+ * all 4 KiB regions within the range, [...] then update the PTE(s), as
+ * described in Section 4.2.1.". That's the equivalent of the Break-Before-Make
+ * approach used by arm64.
+ *
+ * This helper performs the break step for use cases where the
+ * original pte is not needed.
+ */
+static void clear_flush(struct mm_struct *mm,
+			unsigned long addr,
+			pte_t *ptep,
+			unsigned long pgsize,
+			unsigned long ncontig)
+{
+	struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
+	unsigned long i, saddr = addr;
+
+	for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
+		__ptep_get_and_clear(mm, addr, ptep);
+
+	flush_tlb_range(&vma, saddr, addr);
+}
+
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+		     pte_t *ptep, pte_t pte, unsigned long sz)
+{
+	size_t pgsize;
+	int i;
+	int ncontig;
+
+	ncontig = arch_contpte_get_num_contig(ptep, sz, &pgsize);
+
+	if (!pte_present(pte)) {
+		for (i = 0; i < ncontig; i++, ptep++, addr += pgsize)
+			__set_ptes(mm, addr, ptep, pte, 1);
+		return;
+	}
+
+	if (!pte_cont(pte)) {
+		__set_ptes(mm, addr, ptep, pte, 1);
+		return;
+	}
+
+	clear_flush(mm, addr, ptep, pgsize, ncontig);
+
+	set_contptes(mm, addr, ptep, pte, ncontig, pgsize);
+}