[PATCH v4 09/16] arm64/mm: ptep_clear_flush_young(): New layer to manage contig bit

[Ryan Roberts <ryan.roberts@arm.com>]

Create a new layer for the in-table PTE manipulation APIs. For now, The
existing API is prefixed with double underscore to become the
arch-private API and the public API is just a simple wrapper that calls
the private API.

The public API implementation will subsequently be used to transparently
manipulate the contiguous bit where appropriate. But since there are
already some contig-aware users (e.g. hugetlb, kernel mapper), we must
first ensure those users use the private API directly so that the future
contig-bit manipulations in the public API do not interfere with those
existing uses.

Tested-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
 arch/arm64/include/asm/pgtable.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 9b4a9909fd5b..fc1005222ee4 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -138,7 +138,7 @@ static inline pteval_t __phys_to_pte_val(phys_addr_t phys)
  * so that we don't erroneously return false for pages that have been
  * remapped as PROT_NONE but are yet to be flushed from the TLB.
  * Note that we can't make any assumptions based on the state of the access
- * flag, since ptep_clear_flush_young() elides a DSB when invalidating the
+ * flag, since __ptep_clear_flush_young() elides a DSB when invalidating the
  * TLB.
  */
 #define pte_accessible(mm, pte)	\
@@ -904,8 +904,7 @@ static inline int __ptep_test_and_clear_young(struct vm_area_struct *vma,
 	return pte_young(pte);
 }
 
-#define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
-static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
+static inline int __ptep_clear_flush_young(struct vm_area_struct *vma,
 					 unsigned long address, pte_t *ptep)
 {
 	int young = __ptep_test_and_clear_young(vma, address, ptep);
@@ -1119,6 +1118,8 @@ extern void ptep_modify_prot_commit(struct vm_area_struct *vma,
 #define ptep_get_and_clear			__ptep_get_and_clear
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 #define ptep_test_and_clear_young		__ptep_test_and_clear_young
+#define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
+#define ptep_clear_flush_young			__ptep_clear_flush_young
 
 #endif /* !__ASSEMBLY__ */
 
-- 
2.25.1