[PATCH RFC] mm: arm64: advance pte for contpte_ptep_set_access_flags

[Barry Song]

From: Barry Song <v-songbaohua at oppo.com>

Hi Ryan, David,
it seems contpte_ptep_set_access_flags() has never advanced
pte pfn, and it is setting all entries' pfn to the first
subpage. But I feel quite strange we never have a bug reported.
Am I missing something?

Fixes: 4602e5757bcc ("arm64/mm: wire up PTE_CONT for user mappings")
Cc: Ard Biesheuvel <ardb at kernel.org>
Cc: John Hubbard <jhubbard at nvidia.com>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: David Hildenbrand <david at redhat.com>
Cc: Will Deacon <will at kernel.org>
Signed-off-by: Barry Song <v-songbaohua at oppo.com>
---
 arch/arm64/mm/contpte.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c
index a3edced29ac1..10dcd2641184 100644
--- a/arch/arm64/mm/contpte.c
+++ b/arch/arm64/mm/contpte.c
@@ -421,8 +421,10 @@ int contpte_ptep_set_access_flags(struct vm_area_struct *vma,
 		ptep = contpte_align_down(ptep);
 		start_addr = addr = ALIGN_DOWN(addr, CONT_PTE_SIZE);
 
-		for (i = 0; i < CONT_PTES; i++, ptep++, addr += PAGE_SIZE)
+		for (i = 0; i < CONT_PTES; i++, ptep++, addr += PAGE_SIZE) {
 			__ptep_set_access_flags(vma, addr, ptep, entry, 0);
+			entry = pte_advance_pfn(entry, 1);
+		}
 
 		if (dirty)
 			__flush_tlb_range(vma, start_addr, addr,
-- 
2.39.3 (Apple Git-146)