arm64: Do not mask out PTE_RDONLY in pte_same()

Following commit 8c5119144bd9 ("arm64: Move PTE_RDONLY bit handling out
of set_pte_at()"), the PTE_RDONLY bit is no longer managed by
set_pte_at() but built into the PAGE_* attribute definitions.
Consequently, pte_same() must include this bit when checking two PTEs
for equality.

Remove the arm64-specific pte_same() function, practically reverting
commit 09275901bcb1 ("arm64: Fix copy-on-write referencing in HugeTLB")

Fixes: 8c5119144bd9 ("arm64: Move PTE_RDONLY bit handling out of set_pte_at()")
Cc: <stable@vger.kernel.org> # 4.14.x-
Cc: Will Deacon <will@kernel.org>
Cc: Steve Capper <steve.capper@arm.com>
Reported-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 8330810f699e31bd01794f8dc5ad17dd419646f6..565aa45ef1344e481b0ad201194613305a39eb90 100644 (file)
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -283,23 +283,6 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
        set_pte(ptep, pte);
 }
 
-#define __HAVE_ARCH_PTE_SAME
-static inline int pte_same(pte_t pte_a, pte_t pte_b)
-{
-       pteval_t lhs, rhs;
-
-       lhs = pte_val(pte_a);
-       rhs = pte_val(pte_b);
-
-       if (pte_present(pte_a))
-               lhs &= ~PTE_RDONLY;
-
-       if (pte_present(pte_b))
-               rhs &= ~PTE_RDONLY;
-
-       return (lhs == rhs);
-}
-
 /*
  * Huge pte definitions.
  */