[PATCH v3] arm64: hugetlb: enable __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE

[Kefeng Wang]

It is better to use huge page size instead of PAGE_SIZE
for stride when flush hugepage, which reduces the loop
in __flush_tlb_range().

Let's support arch's flush_hugetlb_tlb_range(), which is
used in hugetlb_unshare_all_pmds(), move_hugetlb_page_tables()
and hugetlb_change_protection() for now.

Note, for hugepages based on contiguous bit, it has to be
invalidated individually since the contiguous PTE bit is
just a hint, the hardware may or may not take it into account.

Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
v3: add tlb_level hint by using flush_pud/pmd_tlb_range,
    suggested by Catalin Marinas

 arch/arm64/include/asm/hugetlb.h | 21 +++++++++++++++++++++
 arch/arm64/include/asm/pgtable.h |  4 ++--
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
index 6a4a1ab8eb23..0acb1e8b41e9 100644
--- a/arch/arm64/include/asm/hugetlb.h
+++ b/arch/arm64/include/asm/hugetlb.h
@@ -60,4 +60,25 @@ extern void huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
 
 #include <asm-generic/hugetlb.h>
 
+#define __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
+static inline void flush_hugetlb_tlb_range(struct vm_area_struct *vma,
+					   unsigned long start,
+					   unsigned long end)
+{
+	unsigned long stride = huge_page_size(hstate_vma(vma));
+
+	switch (stride) {
+#ifndef __PAGETABLE_PMD_FOLDED
+	case PUD_SIZE:
+		flush_pud_tlb_range(vma, start, end);
+		break;
+#endif
+	case PMD_SIZE:
+		flush_pmd_tlb_range(vma, start, end);
+		break;
+	default:
+		__flush_tlb_range(vma, start, end, PAGE_SIZE, false, 0);
+	}
+}
+
 #endif /* __ASM_HUGETLB_H */
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 0bd18de9fd97..def402afcbe9 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -35,7 +35,7 @@
 #include <linux/sched.h>
 #include <linux/page_table_check.h>
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLB_PAGE)
 #define __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
 
 /* Set stride and tlb_level in flush_*_tlb_range */
@@ -43,7 +43,7 @@
 	__flush_tlb_range(vma, addr, end, PMD_SIZE, false, 2)
 #define flush_pud_tlb_range(vma, addr, end)	\
 	__flush_tlb_range(vma, addr, end, PUD_SIZE, false, 1)
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLB_PAGE */
 
 static inline bool arch_thp_swp_supported(void)
 {
-- 
2.41.0